bright_id
stringlengths 11
257
| bright_doc
stringlengths 25
9.18M
| bright_split
stringclasses 8
values | scandi_id
stringlengths 3
7
| scandi_url
stringlengths 31
143
| scandi_title
stringlengths 1
79
| scandi_text
stringlengths 15
118k
| scandi_language
stringclasses 4
values | scandi_dist
float64 0.2
1.75
|
|---|---|---|---|---|---|---|---|---|
organism_learn/277716.txt |
Dismiss FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
Dismiss FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
Dismiss FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
Dismiss FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
Dismiss FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
FutureLearn uses cookies to enhance your experience of the website. All but strictly necessary cookies are currently disabled for this browser. Turn on JavaScript to exercise your cookie preferences for all non-essential cookies. You can read FutureLearn's Cookie policy here .
Browse all subjects Business & Management Creative Arts & Media Healthcare & Medicine History IT & Computer Science Language Law Literature Nature & Environment Politics & Society Psychology & Mental Health Science, Engineering & Maths Study Skills Teaching Back to subjects Business & Management Topics Big Data & Analytics Business Ethics Business Strategy Communication Construction CRM Data Analytics Data Visualisation Decision-making Digital Marketing Entrepreneurship Excel View all Business & Management Courses Featured Short Course Communication and Interpersonal Skills at Work Short Course Introduction to Content Design Back to subjects Creative Arts & Media Topics Architecture Cooking Design Digital Media Fashion Interior Design Journalism Music Photography & Visual Arts UX Writing View all Creative Arts & Media Courses Featured Short Course Start Writing Fiction Short Course Innovation: the Fashion Industry Back to subjects Healthcare & Medicine Topics Anatomy Antimicrobial & Antibiotic Resistance Cancer Care Clinical Research Coronavirus Dentistry Diabetes Diagnostics Disease Outbreak Prevention View all Healthcare & Medicine Courses Featured Short Course Food and Mood : Improving Mental Health Through Diet and Nutrition Short Course Exercise in Medicine: From Functional Evaluation to Adapted Exercise Training Back to subjects History Topics Ancient History Archaeology British History Irish History Medieval History Military History Roman History Social History View all History Courses Featured Short Course Historic Landscape Archaeology: Approaches, Methods and Beneficiaries Short Course Railway History: The Rise of the Railway Station Back to subjects IT & Computer Science Topics AI & Robotics Artificial Intelligence (AI) AWS Business Technology Cloud Computing Coding & Programming Cyber Security DevOps Django Ethical Hacking Game Development Generative AI View all IT & Computer Science Courses Featured Short Course Begin Robotics Short Course Computer Programming for Everyone Back to subjects Language Topics IELTS Learn Chinese Learn English Learn French Learn Irish Learn Norwegian Learn Spanish Linguistics View all Language Courses Featured Short Course Introduction to Dutch Short Course English for Academic Study Back to subjects Law Topics Civil Law Criminal Law GDPR Human Rights Law Medical Law View all Law Courses Featured Short Course Exploring Law: Studying Law at University Short Course Introduction to the Rule of Law Back to subjects Nature & Environment Topics Agriculture Climate Change Ecology Food Tech Sustainability View all Nature & Environment Courses Featured Short Course Ecology and Wildlife Conservation Short Course Animal Feed Production: Feed Quality Back to subjects Politics & Society Topics Crime & Criminology Diversity & Inclusion Gender & Feminism Geopolitics Religion Social Issues View all Politics & Society Courses Featured Short Course Why Do People Migrate? Facts Short Course Cultural Diplomacy Back to subjects Psychology & Mental Health Topics Anxiety & Depression Autism Courses & Awareness Training Dementia Emotional Intelligence Mental Health First Aid Mindfulness & Wellbeing Personal Development Personal Training Psychology Self Improvement Sports Psychology Stress Management View all Psychology & Mental Health Courses Featured Short Course Teaching Students Who Have Suffered Complex Trauma Short Course Pupillometry: The Eye as a Window Into the Mind Back to subjects Science, Engineering & Maths Topics Biology & Biotechnology Chemistry Data Science Earth Science Economics Engineering Forensic Science Maths Physics Statistics View all Science, Engineering & Maths Courses Featured Short Course Applications of AI Technology Short Course The Role of Hydrogen in the Clean Energy Transition Back to subjects Teaching Topics Adult Education Curriculum and Learning Design Early Childhood Education Educational Leadership & Administration How to Teach Online Inclusive Teaching Language Teaching Primary Education Teaching Professional Development for Teachers Secondary Education Teaching SEN Education STEM Teaching View all Teaching Courses Featured Short Course The Online Educator: People and Pedagogy Short Course Understanding Multilingual Children’s Language Development Featured Short Course Using Creative Problem Solving Short Course Edward Jenner: 0 – An Introduction to Personal Development Short Course Introduction to Thermodynamics Short Course Blended and Online Learning Design
Browse all subjects Business & Management Creative Arts & Media Healthcare & Medicine History IT & Computer Science Language Law Literature Nature & Environment Politics & Society Psychology & Mental Health Science, Engineering & Maths Study Skills Teaching Back to subjects Business & Management Topics Big Data & Analytics Business Ethics Business Strategy Communication Construction CRM Data Analytics Data Visualisation Decision-making Digital Marketing Entrepreneurship Excel View all Business & Management Courses Featured Short Course Communication and Interpersonal Skills at Work Short Course Introduction to Content Design Back to subjects Creative Arts & Media Topics Architecture Cooking Design Digital Media Fashion Interior Design Journalism Music Photography & Visual Arts UX Writing View all Creative Arts & Media Courses Featured Short Course Start Writing Fiction Short Course Innovation: the Fashion Industry Back to subjects Healthcare & Medicine Topics Anatomy Antimicrobial & Antibiotic Resistance Cancer Care Clinical Research Coronavirus Dentistry Diabetes Diagnostics Disease Outbreak Prevention View all Healthcare & Medicine Courses Featured Short Course Food and Mood : Improving Mental Health Through Diet and Nutrition Short Course Exercise in Medicine: From Functional Evaluation to Adapted Exercise Training Back to subjects History Topics Ancient History Archaeology British History Irish History Medieval History Military History Roman History Social History View all History Courses Featured Short Course Historic Landscape Archaeology: Approaches, Methods and Beneficiaries Short Course Railway History: The Rise of the Railway Station Back to subjects IT & Computer Science Topics AI & Robotics Artificial Intelligence (AI) AWS Business Technology Cloud Computing Coding & Programming Cyber Security DevOps Django Ethical Hacking Game Development Generative AI View all IT & Computer Science Courses Featured Short Course Begin Robotics Short Course Computer Programming for Everyone Back to subjects Language Topics IELTS Learn Chinese Learn English Learn French Learn Irish Learn Norwegian Learn Spanish Linguistics View all Language Courses Featured Short Course Introduction to Dutch Short Course English for Academic Study Back to subjects Law Topics Civil Law Criminal Law GDPR Human Rights Law Medical Law View all Law Courses Featured Short Course Exploring Law: Studying Law at University Short Course Introduction to the Rule of Law Back to subjects Nature & Environment Topics Agriculture Climate Change Ecology Food Tech Sustainability View all Nature & Environment Courses Featured Short Course Ecology and Wildlife Conservation Short Course Animal Feed Production: Feed Quality Back to subjects Politics & Society Topics Crime & Criminology Diversity & Inclusion Gender & Feminism Geopolitics Religion Social Issues View all Politics & Society Courses Featured Short Course Why Do People Migrate? Facts Short Course Cultural Diplomacy Back to subjects Psychology & Mental Health Topics Anxiety & Depression Autism Courses & Awareness Training Dementia Emotional Intelligence Mental Health First Aid Mindfulness & Wellbeing Personal Development Personal Training Psychology Self Improvement Sports Psychology Stress Management View all Psychology & Mental Health Courses Featured Short Course Teaching Students Who Have Suffered Complex Trauma Short Course Pupillometry: The Eye as a Window Into the Mind Back to subjects Science, Engineering & Maths Topics Biology & Biotechnology Chemistry Data Science Earth Science Economics Engineering Forensic Science Maths Physics Statistics View all Science, Engineering & Maths Courses Featured Short Course Applications of AI Technology Short Course The Role of Hydrogen in the Clean Energy Transition Back to subjects Teaching Topics Adult Education Curriculum and Learning Design Early Childhood Education Educational Leadership & Administration How to Teach Online Inclusive Teaching Language Teaching Primary Education Teaching Professional Development for Teachers Secondary Education Teaching SEN Education STEM Teaching View all Teaching Courses Featured Short Course The Online Educator: People and Pedagogy Short Course Understanding Multilingual Children’s Language Development Featured Short Course Using Creative Problem Solving Short Course Edward Jenner: 0 – An Introduction to Personal Development Short Course Introduction to Thermodynamics Short Course Blended and Online Learning Design
Browse all subjects Business & Management Creative Arts & Media Healthcare & Medicine History IT & Computer Science Language Law Literature Nature & Environment Politics & Society Psychology & Mental Health Science, Engineering & Maths Study Skills Teaching
Back to subjects Business & Management Topics Big Data & Analytics Business Ethics Business Strategy Communication Construction CRM Data Analytics Data Visualisation Decision-making Digital Marketing Entrepreneurship Excel View all Business & Management Courses Featured Short Course Communication and Interpersonal Skills at Work Short Course Introduction to Content Design
Back to subjects Business & Management Topics Big Data & Analytics Business Ethics Business Strategy Communication Construction CRM Data Analytics Data Visualisation Decision-making Digital Marketing Entrepreneurship Excel View all Business & Management Courses
Featured Short Course Communication and Interpersonal Skills at Work Short Course Introduction to Content Design
Featured Short Course Communication and Interpersonal Skills at Work Short Course Introduction to Content Design
Back to subjects Creative Arts & Media Topics Architecture Cooking Design Digital Media Fashion Interior Design Journalism Music Photography & Visual Arts UX Writing View all Creative Arts & Media Courses Featured Short Course Start Writing Fiction Short Course Innovation: the Fashion Industry
Back to subjects Creative Arts & Media Topics Architecture Cooking Design Digital Media Fashion Interior Design Journalism Music Photography & Visual Arts UX Writing View all Creative Arts & Media Courses
Back to subjects Healthcare & Medicine Topics Anatomy Antimicrobial & Antibiotic Resistance Cancer Care Clinical Research Coronavirus Dentistry Diabetes Diagnostics Disease Outbreak Prevention View all Healthcare & Medicine Courses Featured Short Course Food and Mood : Improving Mental Health Through Diet and Nutrition Short Course Exercise in Medicine: From Functional Evaluation to Adapted Exercise Training
Back to subjects Healthcare & Medicine Topics Anatomy Antimicrobial & Antibiotic Resistance Cancer Care Clinical Research Coronavirus Dentistry Diabetes Diagnostics Disease Outbreak Prevention View all Healthcare & Medicine Courses
Featured Short Course Food and Mood : Improving Mental Health Through Diet and Nutrition Short Course Exercise in Medicine: From Functional Evaluation to Adapted Exercise Training
Featured Short Course Food and Mood : Improving Mental Health Through Diet and Nutrition Short Course Exercise in Medicine: From Functional Evaluation to Adapted Exercise Training
Back to subjects History Topics Ancient History Archaeology British History Irish History Medieval History Military History Roman History Social History View all History Courses Featured Short Course Historic Landscape Archaeology: Approaches, Methods and Beneficiaries Short Course Railway History: The Rise of the Railway Station
Back to subjects History Topics Ancient History Archaeology British History Irish History Medieval History Military History Roman History Social History View all History Courses
Featured Short Course Historic Landscape Archaeology: Approaches, Methods and Beneficiaries Short Course Railway History: The Rise of the Railway Station
Featured Short Course Historic Landscape Archaeology: Approaches, Methods and Beneficiaries Short Course Railway History: The Rise of the Railway Station
Back to subjects IT & Computer Science Topics AI & Robotics Artificial Intelligence (AI) AWS Business Technology Cloud Computing Coding & Programming Cyber Security DevOps Django Ethical Hacking Game Development Generative AI View all IT & Computer Science Courses Featured Short Course Begin Robotics Short Course Computer Programming for Everyone
Back to subjects IT & Computer Science Topics AI & Robotics Artificial Intelligence (AI) AWS Business Technology Cloud Computing Coding & Programming Cyber Security DevOps Django Ethical Hacking Game Development Generative AI View all IT & Computer Science Courses
Back to subjects Language Topics IELTS Learn Chinese Learn English Learn French Learn Irish Learn Norwegian Learn Spanish Linguistics View all Language Courses Featured Short Course Introduction to Dutch Short Course English for Academic Study
Back to subjects Language Topics IELTS Learn Chinese Learn English Learn French Learn Irish Learn Norwegian Learn Spanish Linguistics View all Language Courses
Back to subjects Law Topics Civil Law Criminal Law GDPR Human Rights Law Medical Law View all Law Courses Featured Short Course Exploring Law: Studying Law at University Short Course Introduction to the Rule of Law
Featured Short Course Exploring Law: Studying Law at University Short Course Introduction to the Rule of Law
Featured Short Course Exploring Law: Studying Law at University Short Course Introduction to the Rule of Law
Back to subjects Nature & Environment Topics Agriculture Climate Change Ecology Food Tech Sustainability View all Nature & Environment Courses Featured Short Course Ecology and Wildlife Conservation Short Course Animal Feed Production: Feed Quality
Back to subjects Nature & Environment Topics Agriculture Climate Change Ecology Food Tech Sustainability View all Nature & Environment Courses
Featured Short Course Ecology and Wildlife Conservation Short Course Animal Feed Production: Feed Quality
Featured Short Course Ecology and Wildlife Conservation Short Course Animal Feed Production: Feed Quality
Back to subjects Politics & Society Topics Crime & Criminology Diversity & Inclusion Gender & Feminism Geopolitics Religion Social Issues View all Politics & Society Courses Featured Short Course Why Do People Migrate? Facts Short Course Cultural Diplomacy
Back to subjects Politics & Society Topics Crime & Criminology Diversity & Inclusion Gender & Feminism Geopolitics Religion Social Issues View all Politics & Society Courses
Back to subjects Psychology & Mental Health Topics Anxiety & Depression Autism Courses & Awareness Training Dementia Emotional Intelligence Mental Health First Aid Mindfulness & Wellbeing Personal Development Personal Training Psychology Self Improvement Sports Psychology Stress Management View all Psychology & Mental Health Courses Featured Short Course Teaching Students Who Have Suffered Complex Trauma Short Course Pupillometry: The Eye as a Window Into the Mind
Back to subjects Psychology & Mental Health Topics Anxiety & Depression Autism Courses & Awareness Training Dementia Emotional Intelligence Mental Health First Aid Mindfulness & Wellbeing Personal Development Personal Training Psychology Self Improvement Sports Psychology Stress Management View all Psychology & Mental Health Courses
Featured Short Course Teaching Students Who Have Suffered Complex Trauma Short Course Pupillometry: The Eye as a Window Into the Mind
Featured Short Course Teaching Students Who Have Suffered Complex Trauma Short Course Pupillometry: The Eye as a Window Into the Mind
Back to subjects Science, Engineering & Maths Topics Biology & Biotechnology Chemistry Data Science Earth Science Economics Engineering Forensic Science Maths Physics Statistics View all Science, Engineering & Maths Courses Featured Short Course Applications of AI Technology Short Course The Role of Hydrogen in the Clean Energy Transition
Back to subjects Science, Engineering & Maths Topics Biology & Biotechnology Chemistry Data Science Earth Science Economics Engineering Forensic Science Maths Physics Statistics View all Science, Engineering & Maths Courses
Featured Short Course Applications of AI Technology Short Course The Role of Hydrogen in the Clean Energy Transition
Featured Short Course Applications of AI Technology Short Course The Role of Hydrogen in the Clean Energy Transition
Back to subjects Teaching Topics Adult Education Curriculum and Learning Design Early Childhood Education Educational Leadership & Administration How to Teach Online Inclusive Teaching Language Teaching Primary Education Teaching Professional Development for Teachers Secondary Education Teaching SEN Education STEM Teaching View all Teaching Courses Featured Short Course The Online Educator: People and Pedagogy Short Course Understanding Multilingual Children’s Language Development
Back to subjects Teaching Topics Adult Education Curriculum and Learning Design Early Childhood Education Educational Leadership & Administration How to Teach Online Inclusive Teaching Language Teaching Primary Education Teaching Professional Development for Teachers Secondary Education Teaching SEN Education STEM Teaching View all Teaching Courses
Featured Short Course The Online Educator: People and Pedagogy Short Course Understanding Multilingual Children’s Language Development
Featured Short Course The Online Educator: People and Pedagogy Short Course Understanding Multilingual Children’s Language Development
Featured Short Course Using Creative Problem Solving Short Course Edward Jenner: 0 – An Introduction to Personal Development Short Course Introduction to Thermodynamics Short Course Blended and Online Learning Design
Short Online Courses Explore Courses with Unlimited ExpertTracks Premium Courses All Short Online Courses Get Unlimited Learning Online Certifications Microcredentials Bootcamps All Online Certifications Online Degrees Business & Management Degrees MBA Degrees Psychology Degrees Teaching Degrees IT & Computer Science Degrees All Online Degrees
Short Online Courses Explore Courses with Unlimited ExpertTracks Premium Courses All Short Online Courses Get Unlimited Learning Online Certifications Microcredentials Bootcamps All Online Certifications Online Degrees Business & Management Degrees MBA Degrees Psychology Degrees Teaching Degrees IT & Computer Science Degrees All Online Degrees
Home / Psychology & Mental Health / Biology & Biotechnology / Research Methods in Psychology: Using Animal Models to Understand Human Behaviour / Mechanisms of learning Learn more about this course. Mechanisms of learning How did psychologists demonstrate these simple but robust mechanisms of learning © University of Padova In the last step, we asked the question: “How did psychologists demonstrate these simple but robust mechanisms of learning?” To answer this question we need to go back to 1913, when Watson wrote an article entitled Psychology as the behaviorist views it, with a number of assumptions regarding methodology and behavioural analysis. “Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158). This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled. Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course The Skinner Box One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned. With respect to the latter issue, different schedules were investigated: Fixed-ratio schedule : Animals receive a pellet after they touch the key a certain number of times; for example, they would receive a pellet after every five touches. Variable-ratio schedule : Subjects receive reinforcement after a random number of responses (see video 3.10 on “intermittent reinforcement”). Fixed-interval schedule : Subjects receive a pellet after a designated period of time has elapsed; for example, every 3 minutes. Variable-interval schedule : Subjects receive a pellet at random intervals of time. Application to humans Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour. This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020). Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick? The carrot or the stick According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue. For that, we would need to ask rats! We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course Share this See other articles from this course This article is from the online course: Research Methods in Psychology: Using Animal Models to Understand Human Behaviour Created by Join Now
Home / Psychology & Mental Health / Biology & Biotechnology / Research Methods in Psychology: Using Animal Models to Understand Human Behaviour / Mechanisms of learning Learn more about this course. Mechanisms of learning How did psychologists demonstrate these simple but robust mechanisms of learning © University of Padova In the last step, we asked the question: “How did psychologists demonstrate these simple but robust mechanisms of learning?” To answer this question we need to go back to 1913, when Watson wrote an article entitled Psychology as the behaviorist views it, with a number of assumptions regarding methodology and behavioural analysis. “Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158). This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled. Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course The Skinner Box One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned. With respect to the latter issue, different schedules were investigated: Fixed-ratio schedule : Animals receive a pellet after they touch the key a certain number of times; for example, they would receive a pellet after every five touches. Variable-ratio schedule : Subjects receive reinforcement after a random number of responses (see video 3.10 on “intermittent reinforcement”). Fixed-interval schedule : Subjects receive a pellet after a designated period of time has elapsed; for example, every 3 minutes. Variable-interval schedule : Subjects receive a pellet at random intervals of time. Application to humans Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour. This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020). Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick? The carrot or the stick According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue. For that, we would need to ask rats! We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course Share this See other articles from this course This article is from the online course: Research Methods in Psychology: Using Animal Models to Understand Human Behaviour Created by Join Now
Home / Psychology & Mental Health / Biology & Biotechnology / Research Methods in Psychology: Using Animal Models to Understand Human Behaviour / Mechanisms of learning
Mechanisms of learning How did psychologists demonstrate these simple but robust mechanisms of learning © University of Padova In the last step, we asked the question: “How did psychologists demonstrate these simple but robust mechanisms of learning?” To answer this question we need to go back to 1913, when Watson wrote an article entitled Psychology as the behaviorist views it, with a number of assumptions regarding methodology and behavioural analysis. “Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158). This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled. Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course The Skinner Box One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned. With respect to the latter issue, different schedules were investigated: Fixed-ratio schedule : Animals receive a pellet after they touch the key a certain number of times; for example, they would receive a pellet after every five touches. Variable-ratio schedule : Subjects receive reinforcement after a random number of responses (see video 3.10 on “intermittent reinforcement”). Fixed-interval schedule : Subjects receive a pellet after a designated period of time has elapsed; for example, every 3 minutes. Variable-interval schedule : Subjects receive a pellet at random intervals of time. Application to humans Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour. This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020). Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick? The carrot or the stick According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue. For that, we would need to ask rats! We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course Share this See other articles from this course This article is from the online course: Research Methods in Psychology: Using Animal Models to Understand Human Behaviour Created by Join Now
Mechanisms of learning How did psychologists demonstrate these simple but robust mechanisms of learning © University of Padova In the last step, we asked the question: “How did psychologists demonstrate these simple but robust mechanisms of learning?” To answer this question we need to go back to 1913, when Watson wrote an article entitled Psychology as the behaviorist views it, with a number of assumptions regarding methodology and behavioural analysis. “Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158). This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled. Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course The Skinner Box One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned. With respect to the latter issue, different schedules were investigated: Fixed-ratio schedule : Animals receive a pellet after they touch the key a certain number of times; for example, they would receive a pellet after every five touches. Variable-ratio schedule : Subjects receive reinforcement after a random number of responses (see video 3.10 on “intermittent reinforcement”). Fixed-interval schedule : Subjects receive a pellet after a designated period of time has elapsed; for example, every 3 minutes. Variable-interval schedule : Subjects receive a pellet at random intervals of time. Application to humans Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour. This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020). Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick? The carrot or the stick According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue. For that, we would need to ask rats! We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course Share this See other articles from this course
Mechanisms of learning How did psychologists demonstrate these simple but robust mechanisms of learning © University of Padova In the last step, we asked the question: “How did psychologists demonstrate these simple but robust mechanisms of learning?” To answer this question we need to go back to 1913, when Watson wrote an article entitled Psychology as the behaviorist views it, with a number of assumptions regarding methodology and behavioural analysis. “Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158). This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled. Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course The Skinner Box One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned. With respect to the latter issue, different schedules were investigated: Fixed-ratio schedule : Animals receive a pellet after they touch the key a certain number of times; for example, they would receive a pellet after every five touches. Variable-ratio schedule : Subjects receive reinforcement after a random number of responses (see video 3.10 on “intermittent reinforcement”). Fixed-interval schedule : Subjects receive a pellet after a designated period of time has elapsed; for example, every 3 minutes. Variable-interval schedule : Subjects receive a pellet at random intervals of time. Application to humans Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour. This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020). Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick? The carrot or the stick According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue. For that, we would need to ask rats! We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course Share this See other articles from this course
In the last step, we asked the question: “How did psychologists demonstrate these simple but robust mechanisms of learning?” To answer this question we need to go back to 1913, when Watson wrote an article entitled Psychology as the behaviorist views it, with a number of assumptions regarding methodology and behavioural analysis. “Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158). This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled. Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course The Skinner Box One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned. With respect to the latter issue, different schedules were investigated: Fixed-ratio schedule : Animals receive a pellet after they touch the key a certain number of times; for example, they would receive a pellet after every five touches. Variable-ratio schedule : Subjects receive reinforcement after a random number of responses (see video 3.10 on “intermittent reinforcement”). Fixed-interval schedule : Subjects receive a pellet after a designated period of time has elapsed; for example, every 3 minutes. Variable-interval schedule : Subjects receive a pellet at random intervals of time. Application to humans Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour. This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020). Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick? The carrot or the stick According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue. For that, we would need to ask rats! We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
In the last step, we asked the question: “How did psychologists demonstrate these simple but robust mechanisms of learning?” To answer this question we need to go back to 1913, when Watson wrote an article entitled Psychology as the behaviorist views it, with a number of assumptions regarding methodology and behavioural analysis. “Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158). This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled. Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course The Skinner Box One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned. With respect to the latter issue, different schedules were investigated: Fixed-ratio schedule : Animals receive a pellet after they touch the key a certain number of times; for example, they would receive a pellet after every five touches. Variable-ratio schedule : Subjects receive reinforcement after a random number of responses (see video 3.10 on “intermittent reinforcement”). Fixed-interval schedule : Subjects receive a pellet after a designated period of time has elapsed; for example, every 3 minutes. Variable-interval schedule : Subjects receive a pellet at random intervals of time. Application to humans Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour. This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020). Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick? The carrot or the stick According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue. For that, we would need to ask rats! We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
To answer this question we need to go back to 1913, when Watson wrote an article entitled Psychology as the behaviorist views it, with a number of assumptions regarding methodology and behavioural analysis. “Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158). This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled. Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course The Skinner Box One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned. With respect to the latter issue, different schedules were investigated: Fixed-ratio schedule : Animals receive a pellet after they touch the key a certain number of times; for example, they would receive a pellet after every five touches. Variable-ratio schedule : Subjects receive reinforcement after a random number of responses (see video 3.10 on “intermittent reinforcement”). Fixed-interval schedule : Subjects receive a pellet after a designated period of time has elapsed; for example, every 3 minutes. Variable-interval schedule : Subjects receive a pellet at random intervals of time. Application to humans Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour. This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020). Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick? The carrot or the stick According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue. For that, we would need to ask rats! We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
“Psychology as a behaviorist views it, is a purely objective experimental branch of natural science. Its theoretical goal is … prediction and control.” (p. 158).
This perspective, called behaviourism , is primarily concerned with observable behaviour, as opposed to internal events like thinking and emotion of previous psychoanalysts. To bring learning studies into the field of natural science, controlled laboratory studies were necessary. As behaviourists did not believe there were fundamental (qualitative) distinctions between human and animal behaviour, research was mainly carried out on animals. Consequently, rats and pigeons became the primary source of data, as their environments could be easily controlled.
Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Want to keep learning? This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
This content is taken from University of Padova online course, Research Methods in Psychology: Using Animal Models to Understand Human Behaviour
One of the most influential authors in this field was B.F. Skinner (1904-1990). This scientist invented an operant conditioning apparatus to study learning mechanisms in rats and pigeons, the so-called Skinner box (1938). This box is an enclosed apparatus containing a bar or key that an animal can manipulate in order to obtain reinforcement. The chamber also has a device that records each response provided by the subject as well as the unique schedule of reinforcement that the animal was assigned.
Animal studies are fundamental in understanding the most effective types of learning that won’t be easily forgotten. Such learning schedules are commonly applied to humans, both in normal and abnormal behaviours. For instance, Applied Behavioural Analysis (ABA) is a range of different strategies and techniques that are commonly used to teach autistic people new skills and reduce their difficult behaviour.
This is entirely based on the learning mechanisms investigated in pigeons and rats by Skinner and collaborators. ABA can help increase functional skills or decrease problematic behaviours. Some examples of behaviours that ABA can help increase include communication skills and social skills. ABA can help decrease behaviours such as aggression, property destruction, and self-injurious behaviour. How? By coping with (positive/negative) rewards and (positive/negative) punishments. Research has shown that ABA is effective in reducing disruptive behaviours typically observed in individuals with a diagnosis of autism spectrum disorder, thus making it the most important therapy for this heterogeneous range of neurodevelopmental disorders (Yu et al., 2020).
Last but not the least… at the end of this reading you may ask: which is more effective, reward or punishment? Simply put: the carrot or the stick?
According to a recent study, the effects of punishments on choice behaviour can be about three times more potent than the effects of rewards (see Kubanek et al., 2015). This data was collected from humans, published in an important journal in the field of cognition, and received lots of media coverage—but guess what? More than one century ago (Hoge & Stocking, 1912) we already had an initial answer to this issue.
We’ll find out more in the next step. References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
References Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Hoge, M. A., & Stocking, R. J. (1912). A note on the relative value of punishment and reward as motives. Journal of Animal Behavior, 2(1), 43. Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Kubanek, J., Snyder, L. H., & Abrams, R. A. (2015). Reward and punishment act as distinct factors in guiding behavior. Cognition, 139, 154-167. Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Skinner, B. F. (1938). Behavior of organisms. New York: Appleton-Century-Crofts. Watson, J. B. (1913). Psychology as the behaviorist views it. Psychological Review, 20(2), 158–177. Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Yu, Q., Li, E., Li, L., & Liang, W. (2020). Efficacy of interventions based on applied behavior analysis for autism spectrum disorder: A meta-analysis. Psychiatry investigation, 17(5), 432. © University of Padova Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
Want to keep learning? This content is taken from University of Padova online course Research Methods in Psychology: Using Animal Models to Understand Human Behaviour View Course
This article is from the online course: Research Methods in Psychology: Using Animal Models to Understand Human Behaviour Created by Join Now
This article is from the online course: Research Methods in Psychology: Using Animal Models to Understand Human Behaviour Created by Join Now
This article is from the online course: Research Methods in Psychology: Using Animal Models to Understand Human Behaviour Created by Join Now
This article is from the free online Research Methods in Psychology: Using Animal Models to Understand Human Behaviour Created by Join Now
This article is from the free online Research Methods in Psychology: Using Animal Models to Understand Human Behaviour Created by Join Now
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now
Reach your personal and professional goals Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates. Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas. Start Learning now
Unlock access to hundreds of expert online courses and degrees from top universities and educators to gain accredited qualifications and professional CV-building certificates.
Join over 18 million learners to launch, switch or build upon your career, all at your own pace, across a wide range of topic areas.
Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Register to receive updates Create an account to receive our newsletter, course recommendations and promotions. Register for free
Subjects Find the ideal course for you Short courses Learn new skills with a flexible online course ExpertTracks Upskill with a series of specialist courses Microcredentials Earn professional or academic accreditation Online degrees Study flexibly online as you build to a degree
Subjects Find the ideal course for you Short courses Learn new skills with a flexible online course ExpertTracks Upskill with a series of specialist courses Microcredentials Earn professional or academic accreditation Online degrees Study flexibly online as you build to a degree
Expert Tracks Train the Trainer: Certificate in Corporate Training Advanced Cyber Security Training Project Management and its Role in Effective Business Short Courses People Management Skills Computer Programming for Everyone Train the Healthcare Trainer The Freelance Bible: How to Be a Freelancer in Any Industry Microcredentials Degrees MBAs Business & Management degrees Healthcare degrees IT & Computer Science degrees Psychology degrees
Expert Tracks Train the Trainer: Certificate in Corporate Training Advanced Cyber Security Training Project Management and its Role in Effective Business Short Courses People Management Skills Computer Programming for Everyone Train the Healthcare Trainer The Freelance Bible: How to Be a Freelancer in Any Industry Microcredentials Degrees MBAs Business & Management degrees Healthcare degrees IT & Computer Science degrees Psychology degrees
Expert Tracks Train the Trainer: Certificate in Corporate Training Advanced Cyber Security Training Project Management and its Role in Effective Business
Short Courses People Management Skills Computer Programming for Everyone Train the Healthcare Trainer The Freelance Bible: How to Be a Freelancer in Any Industry
Degrees MBAs Business & Management degrees Healthcare degrees IT & Computer Science degrees Psychology degrees
Join FutureLearn today Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Join FutureLearn today Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Join FutureLearn today Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Join FutureLearn today Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Join FutureLearn today Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Join FutureLearn today Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Join FutureLearn today Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Join FutureLearn today Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox. Sign up now
Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox.
Register for a FutureLearn account to get personalised course recommendations and offers straight to your inbox.
About FutureLearn Our values Our advisory board Our partners Become a partner Work at FutureLearn Futurelearn Scholarship Press Blog Using FutureLearn Using our platform Learning Guide Certificates Unlimited Microcredentials ExpertTracks Need Some Help? FAQs Child Safety Help Centre Contact Popular Subjects Business and Management Healthcare and Medicine Teaching Psychology and Mental Health IT and Computer Science Featured Courses Developing Skills FutureLearn for Business FutureLearn Schools Healthcare Training Course Collections Career Advice Small Print T&Cs Privacy policy Cookie policy Code of conduct Accessibility policy Sitemap Open steps sitemap
About FutureLearn Our values Our advisory board Our partners Become a partner Work at FutureLearn Futurelearn Scholarship Press Blog Using FutureLearn Using our platform Learning Guide Certificates Unlimited Microcredentials ExpertTracks Need Some Help? FAQs Child Safety Help Centre Contact Popular Subjects Business and Management Healthcare and Medicine Teaching Psychology and Mental Health IT and Computer Science Featured Courses Developing Skills FutureLearn for Business FutureLearn Schools Healthcare Training Course Collections Career Advice Small Print T&Cs Privacy policy Cookie policy Code of conduct Accessibility policy Sitemap Open steps sitemap
About FutureLearn Our values Our advisory board Our partners Become a partner Work at FutureLearn Futurelearn Scholarship Press Blog Using FutureLearn Using our platform Learning Guide Certificates Unlimited Microcredentials ExpertTracks Need Some Help? FAQs Child Safety Help Centre Contact Popular Subjects Business and Management Healthcare and Medicine Teaching Psychology and Mental Health IT and Computer Science Featured Courses Developing Skills FutureLearn for Business FutureLearn Schools Healthcare Training Course Collections Career Advice Small Print T&Cs Privacy policy Cookie policy Code of conduct Accessibility policy Sitemap Open steps sitemap
About FutureLearn Our values Our advisory board Our partners Become a partner Work at FutureLearn Futurelearn Scholarship Press Blog
Our values Our advisory board Our partners Become a partner Work at FutureLearn Futurelearn Scholarship Press Blog
Popular Subjects Business and Management Healthcare and Medicine Teaching Psychology and Mental Health IT and Computer Science Featured Courses
Business and Management Healthcare and Medicine Teaching Psychology and Mental Health IT and Computer Science Featured Courses
Developing Skills FutureLearn for Business FutureLearn Schools Healthcare Training Course Collections Career Advice
Small Print T&Cs Privacy policy Cookie policy Code of conduct Accessibility policy Sitemap Open steps sitemap | biology | 387471 | https://da.wikipedia.org/wiki/Action%20Learning | Action Learning | Action Learning er en dialogbaseret læringsmetode og undervisningsform, der er baseret dels på David Kolb’s læringscyklus, dels på Action Learning metoden, der blev udviklet af professor ved Cambridge University, Reg Revans. Action Learning som undervisningsform ses anvendt i større og større grad – ofte på lederuddannelser og enkelte steder også på længerevarende, videregående uddannelser.
Læringscyklus
Action Learning tager bl.a. afsæt i David A. Kolb's teorier om læring – herunder hans læringscyklus.
Kolbs teori er, at for at læring finder sted, skal man gennemgå en fire trins cyklus: Oplevelse → refleksion/observation → abstrakt konceptualisering → aktiv eksperimentering. Forandrende læring forekommer, når man kommer hele vejen rundt gennem cirklen.
Ud fra Kolbs model er der udviklet læringsmetoder, der aktivt engagerer deltagerne til at anvende teori, viden og begreber – ikke kun i tests og prøver, men også i konkrete oplevelser og i refleksion.
Action Learning – filosofi, teori og metode
Ophavsmanden til Action Learning er Reg Revans. Action Learning er en læringsproces, hvor deltageren undersøger egne handlinger og erfaringer for at forbedre sine præstationer. Dette gøres i samarbejde med andre og i mindre grupper – også kaldet Action Learning Sets. Det er Revans tese, at vi lærer mest og bedst ved at arbejde med aktuelle problemer i situationer, hvor man modtager en hurtig og klar feedback på beslutninger – helst i samarbejde med andre, der er i en lignende situation.
Vigtige teoretiske pointer
Revans skelnede mellem ’teoretiske problemstillinger’ og ’virkelige problemer’, hvor Action Learning er i stand til at løse virkelige problemer ved eksempelvis at forbedre produktivitet og moral blandt medarbejdere frem for at løse teoretiske problemstillinger i produktion af årsregnskaber, statusrapporter mv. Han fandt også frem til, at der var forskel på intelligens og visdom, som kommer til udtryk gennem indsigtsfulde spørgsmål. Han demonstrerede, at den effektive læring opstår i samspil med andre. Netop på den baggrund bliver ’Action Learning Sets’ benyttet flittigt i forskellige Action Learning forløb.
Andre nøgleforfattere
Nøgleforfattere i England er Mike Paedler og Alan Mumford, og i USA er emnet behandlet af forfattere som Michael Marquardt og Joe Raelin. Revans opnåede stor anerkendelse i Belgien, hvor han kombinerede højere uddannelsesforløb med industrien, hvilket skabte resultater i form af et fornyet boost til nationaløkonomien. Revans’ teori om Action Learning blev citeret af Stuart Crainer som en af de 75 største ‘Management Decisions Ever Made’ i hans bog af samme navn.
En utraditionel metode
Action Learning står i kontrast til mere traditionelle læringsmetoder, som fokuserer på demonstration af viden og færdigheder. Metoden har i højere grad fokus på at generere ny viden gennem konkrete handlinger, som fører til nye og forbedrede kompetencer og præstationer. Action Learning flytter dermed fokus fra underviseren over på deltageren.
Optimering af uformelle læringsprocesser
Action Learning har fokus på den uformelle læring, og hvordan den kan styrkes på en bevidst måde ved at lade læringen foregå i en fælles, genkendelig og struktureret ramme. Det gør den enkelte i stand til at udvikle sig i den retning og med den hastighed, som er optimalt for ham/hende. Uformel læring er personlig, da det er individet, der tager ansvar for egen udvikling og læring.
Action Learning på formel – at stille spørgsmål skaber viden
Q består af 4 'hovedspørgsmålstyper':
Hvor
Hvem
Hvornår
Hvad
Og tre mindre spørgsmålstyper:
Hvorfor
Hvor mange
Hvor meget?
Fundamentet for et Action Learning læringsmiljø
For at Action Learning processer kan fungere optimalt, skal følgende grundelementer være tilstede i læringsmiljøet:
Problem/spørgsmål
Hver deltager skal have formuleret et problem eller ‘spørgsmål’, som er væsentligt nok til retfærdiggøre, at det også er i organisationens interesse som helhed at få løst det pågældende problem
Sets
Begrebet ‘set’ benyttes i Action Learning teorien som betegnelse for gruppen af deltagere. En Action Learning gruppe består typisk af 20-40 personer. Hvert set er yderligere opdelt i undergrupper bestående af 5-7 deltagere hver. Hovedparten af læringen foregår i undergrupperne. Hovedgruppen mødes typisk med jævne mellemrum – hver 6.-8. uge – og undergrupperne i intervalerne mellem de fælles møder.
Spørgeteknik
Noget af det centrale i Action Learning forløbet er den sokratiske spørgeform. Undergrupperne støtter hinanden i den individuelle problemløsning og læringsproces ved hjælp af denne spørgeteknik.
Læring
For at læring skal kunne finde sted under Action Learning forløbet, skal der være tid til refleksion. Det er undervisernes opgave at sikre, at løbende refleksion – og dokumentation af disse – finder sted i grupperne. Derfor skal deltagerne blandt andet løbende nedfælde deres refleksioner i en såkaldt ‘learning log’, som fungerer som en slags personlig dagbog over forløbet.
Underviser
Underviseren fungerer som coach eller facilitator for gruppen. Han eller hun støtter deltagerne i at arbejde med Action Learning ved at guide deltagerne i spørgeteknik og opmuntre dem til refleksion over og dokumentation af deres erfaringer.
Eksterne henvisninger
Experiental Learning
David A. Kolb
Action Learning Reg Revans
Engelsk wikipedia om Reg Revans
Ledelse
Læring | danish | 0.536942 |
organism_learn/05_Mechanisms_of_Learning.htm.txt |
Розділ в розробці Тести КРОК Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти актуальні тести КРОК та допомогу в їх розвязанні. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти актуальні тести КРОК та допомогу в їх розвязанні. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти актуальні тести КРОК та допомогу в їх розвязанні.
Розділ в розробці Теорія Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти теорію. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти теорію. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Розділ в розробці Конференції Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти інформацію про конференції. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти інформацію про конференції. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти інформацію про конференції.
Розділ в розробці Форум Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти медичний форум. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти медичний форум. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Розділ в розробці Університети Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти інформацію про університети. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти інформацію про університети. Отримайте повідомлення коли цей розділ буде запущено! Ваша пошта:
Наразі цей розділ знаходиться в розробці. У майбутньому - тут ви зможете знайти інформацію про університети.
MECHANISMS OF LEARNING Learning Learning is a relatively permanent change in an organism’s behavior due to experience. In associative learning, we learn to associate two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning). In observational learning, we learn by watching others’ experiences and examples. Learned associations also feed our habitual behaviors . As we repeat behaviors in a given context—the sleeping posture we associate with bed, our walking routes on campus, our eating popcorn in a movie theater —the behaviors become associated with the contexts. Our next experience of the context then automatically triggers the habitual response. Such associations can make it hard to kick a smoking habit; when back in the smoking context, the urge to light up can be powerful. By linking two events that occur close together, both the sea slug and the seals exhibit associative learning. The sea slug associates the squirt with an impending shock; the seal associates slapping and barking with a herring treat. Each animal has learned something important to its survival: predicting the immediate future. Conditioning is the process of learning associations. In classical conditioning, we learn to associate two stimuli and thus to anticipate events. We learn that a flash of lightning signals an impending crack of thunder, so when lightning flashes nearby, we start to brace ourselves. In operant conditioning, we learn to associate a response (our behavior ) and its consequence and thus to repeat acts followed by good results and avoid acts followed by bad results. Conditioning is not the only form of learning. Through observational learning, we learn from others’ experiences. Chimpanzees, too, may learn behaviors merely by watching others perform them. If one sees another solve a puzzle and gain a food reward, the observer may perform the trick more quickly. By conditioning and by observation we humans learn and adapt to our environments. We learn to expect and prepare for significant events such as food or pain (classical conditioning). We also learn to repeat acts that bring good results and to avoid acts that bring bad results (operant conditioning). By watching others we learn new behaviors (observational learning). And through language, we also learn things we have neither experienced nor observed. Classical Conditioning. Classical conditioning is a type of learning in which an organism comes to associate stimuli. Pavlov’s work on classical conditioning laid the foundation for behaviorism , the view that psychology should be an objective science that studies behavior without reference to mental processes. Although learning by association had been discussed for centuries, it remained for Ivan Pavlov to capture the phenomenon in his classic experiments on conditioning. In classical conditioning, a unconditional reflex (UR) is an event that occurs naturally (such as salivation), in response to some stimulus. A unconditional stimulus (US) is something that naturally and automatically (without learning) triggers the unlearned response (as food in the mouth triggers salivation). A conditional stimulus (CS) is a previously irrelevant stimulus (such as a bell) that, through learning, comes to be associated with some unlearned response (salivating). A conditional reflex (CR) is the learned response (salivating) to the originally irrelevant but now conditioned stimulus. In classical conditioning, acquisition is associating a CS with the US. Acquisition occurs most readily when a CS is presented just before (ideally, about a half-second before) a US, preparing the organism for the upcoming event. This finding supports the view that classical conditioning is biologically adaptive. Extinction is diminished responding when the CS no longer signals an impending US. Spontaneous recovery is the appearance of a formerly extinguished response, following a rest period. Generalization is the tendency to respond to stimuli that are similar to a CS. Discrimination is the learned ability to distinguish between a CS and other irrelevant stimuli. The behaviorists’ optimism that in any species, any response can be conditioned to any stimulus has been tempered. Conditioning principles, we now know, are cognitively and biologically constrained. In classical conditioning, animals learn when to expect a US, and they may be aware of the link between stimuli and responses. Moreover, because of biological predispositions, learning some associations is easier than learning others. Learning is adaptive: Each species learns behaviors that aid its survival. Pavlov taught us that significant psychological phenomena can be studied objectively, and that classical conditioning is a basic form of learning that applies to all species. Later research modified this finding somewhat by showing that in many species cognition and biological predispositions place some limits on conditioning. Classical conditioning techniques are used in treatment programs for those recovering from cocaine and other drug abuse and to condition more appropriate responses in therapy for emotional disorders. The body’s immune system also appears to respond to classical conditioning. Pavlov’s Experiments. Pavlov was driven by a lifelong passion for research. After setting aside his initial plan to follow his father into the Russian Orthodox priesthood, Pavlov received a medical degree at age 33 and spent the next two decades studying the digestive system. This work earned him Russia’s first Nobel prize in 1904. But it was his novel experiments on learning, to which he devoted the last three decades of his life, that earned this feisty scientist his place in history. Pavlov’s new direction came when his creative mind seized on an incidental observation. Without fail, putting food in a dog’s mouth caused the animal to salivate. Moreover, the dog began salivating not only to the taste of the food, but also to the mere sight of the food, or the food dish, or the person delivering the food, or even the sound of that person’s approaching footsteps. At first, Pavlov considered these “psychic secretions” an annoyance—until he realized they pointed to a simple but important form of learning. Pavlov and his assistants tried to imagine what the dog was thinking and feeling as it drooled in anticipation of the food. This only led them into fruitless debates. So, to explore the phenomenon more objectively, they experimented. To eliminate other possible influences, they isolated the dog in a small room, secured it in a harness, and attached a device to divert its saliva to a measuring instrument. From the next room, they presented food—first by sliding in a food bowl, later by blowing meat powder into the dog’s mouth at a precise moment. They then paired various neutral events—something the dog could see or hear but didn’t associate with food—with food in the dog’s mouth. If a sight or sound regularly signaled the arrival of food, would the dog learn the link? If so, would it begin salivating in anticipation of the food? The answers proved to be yes and yes. Just before placing food in the dog’s mouth to produce salivation, Pavlov sounded a tone. After several pairings of tone and food, the dog, anticipating the meat powder, began salivating to the tone alone. In later experiments, a buzzer, a light, a touch on the leg, even the sight of a circle set off the drooling. (This procedure works with people, too. When hungry young Londoners viewed abstract figures before smelling peanut butter or vanilla, their brains soon were responding in anticipation to the abstract images alone). Because salivation in response to food in the mouth was unlearned, Pavlov called it an unconditioned response (UR). Food in the mouth automatically, unconditionally, triggers a dog’s salivary reflex. Thus, Pavlov called the food stimulus an unconditioned stimulus (US). Pavlov repeatedly presented a neutral stimulus (such as a tone) just before an unconditioned stimulus (UCS, food) that triggered an unconditioned response (UCR, salivation). After several repetitions, the tone alone (now the conditioned stimulus, CS) triggered a conditioned response (CR, salivation). Further experiments on acquisition revealed that classical conditioning was usually greatest when the CS was presented just before the UCS, thus preparing the organism for what was coming. Other experiments explored the phenomena of acquisition, extinction, spontaneous recovery, generalization, and discrimination. Salivation in response to the tone was conditional upon the dog’s learning the association between the tone and the food. Today we call this learned response the conditioned response (CR). The previously neutral (in this context) tone stimulus that now triggered the conditional salivation we call the conditioned stimulus (CS). Distinguishing these two kinds of stimuli and responses is easy: Conditioned =learned; unconditioned = unlearned. Pavlov’s work laid a foundation for John B. Watson’s emerging belief that psychology, to be an objective science, should study only overt behavior , without considering unobservable mental activity. Watson called this position behaviorism . Extending Pavlov’s Understanding . The behaviorists’ optimism that learning principles would generalize from one response to another and from one species to another has been tempered. Conditioning principles, we now know, are cognitively influenced and biologically constrained. In classical conditioning, animals learn when to "expect" an unconditioned stimulus. Moreover, animals are biologically predisposed to learn associations between, say, a peculiar taste and a drink that will make them sick, which they will then avoid. They don’t, however, learn to avoid a sickening drink announced by a noise. To understand the acquisition, or initial learning, of the stimulus-response relationship, Pavlov and his associates had to confront the question of timing: How much time should elapse between presenting the neutral stimulus (the tone, the light, the touch) and the unconditioned stimulus? In most cases, not much—half a second usually works well. What do you suppose would happen if the food (US) appeared before the tone (CS) rather than after? Would conditioning occur? Not likely. With but a few exceptions, conditioning doesn’t happen when the CS follows the US. Remember, classical conditioning is biologically adaptive because it helps humans and other animals prepare for good or bad events. To Pavlov’s dogs, the tone (CS) signaled an important biological event—the arrival of food (US). To deer in the forest, the snapping of a twig (CS) may signal a predator’s approach (US). If the good or bad event had already occurred, the CS would not likely signal anything significant. Extinction and Spontaneous Recovery After conditioning, what happens if the CS occurs repeatedly without the US? Will the CS continue to elicit the CR? Pavlov discovered that when he sounded the tone again and again without presenting food, the dogs salivated less and less. Their declining salivation illustrates extinction , the diminished responding that occurs when the CS (tone) no longer signals an impending US (food). Pavlov found, however, that if he allowed several hours to elapse before sounding the tone again, the salivation to the tone would reappear spontaneously. This spontaneous recovery—the reappearance of a (weakened) CR after a pause—suggested to Pavlov that extinction was suppressing the CR rather than eliminating it. After breaking up with his fire-breathing heartthrob, Tirrell also experienced extinction and spontaneous recovery. He recalls that “the smell of onion breath (CS), no longer paired with the kissing (US), lost its ability to shiver my timbers. Occasionally, though, after not sensing the aroma for a long while, smelling onion breath awakens a small version of the emotional response I once felt.” Generalization Pavlov and his students noticed that a dog conditioned to the sound of one tone also responded somewhat to the sound of a different tone that had never been paired with food. Likewise, a dog conditioned to salivate when rubbed would also drool a bit when scratched or when touched on a different body part. This tendency to respond to stimuli similar to the CS is called generalization. Generalization can be adaptive, as when toddlers taught to fear moving cars also become afraid of moving trucks and motorcycles. So automatic is generalization that one Argentine writer who underwent torture still recoils with fear when he sees black shoes—his first glimpse of his torturers as they approached his cell. Generalization of anxiety reactions has been demonstrated in laboratory studies comparing abused with nonabused children. Shown an angry face on a computer screen, abused children’s brain-wave responses are dramatically stronger and longer lasting. Because of generalization, stimuli similar to naturally disgusting or appealing objects will, by association, evoke some disgust or liking. Normally desirable foods, such as fudge, are unappealing when shaped to resemble dog feces . Adults with childlike facial features (round face, large forehead, small chin, large eyes) are perceived as having childlike warmth, submissiveness, and naiveté. In both cases, people’s emotional reactions to one stimulus generalize to similar stimuli. Discrimination Pavlov’s dogs also learned to respond to the sound of a particular tone and not to other tones. Discrimination is the learned ability to distinguish between a conditioned stimulus (which predicts the US) and other irrelevant stimuli. Being able to recognize differences is adaptive. Slightly different stimuli can be followed by vastly different consequences. Confronted by a pit bull, your heart may race; confronted by a golden retriever, it probably will not. Pavlov’s Legacy. Pavlov taught us that principles of learning apply across species that significant psychological phenomena can be studied objectively, and that conditioning principles have important practical applications. Through higher-order conditioning, a new neutral stimulus can become a new conditioned stimulus. All that’s required is for it to become associated with a previously conditioned stimulus. If a tone regularly signals food and produces salivation, then a light that becomes associated with the tone may also begin to trigger salivation. Although this higher-order conditioning (also called second-order conditioning) tends to be weaker than first-stage conditioning, it influences our everyday lives. Imagine that something makes us very afraid (perhaps a pit bull dog associated with a previous dog bite). If something else, such as the sound of a barking dog, brings to mind that pit bull, the bark alone may make us feel a little afraid. Associations can influence attitudes. As Andy Field showed British children novel cartoon characters alongside either ice cream (Yum!) or Brussels sprouts (Yuk!), the children came to like best the ice-cream–associated characters. Michael Olson and Russell Fazio classically conditioned adults’ attitudes, using little-known Pokémon characters. The participants, playing the role of a security guard monitoring a video screen, viewed a stream of words, images, and Pokémon characters. Their task, they were told, was to respond to one target Pokémon character by pressing a button. Unnoticed by the participants, when two other Pokémon characters appeared on the screen, one was consistently associated with various positive words and images (such as awesome or a hot fudge sundae); the other appeared with negative words and images (such as awful or a cockroach). Without any conscious memory for the pairings, the participants formed more gut-level positive attitudes for the characters associated with the positive stimuli. Follow-up studies indicate that conditioned likes and dislikes are even stronger when people notice and are aware of the associations they have learned. Operant Conditioning. Classical conditioning and operant conditioning are both forms of associativelearning , yet their difference is straightforward: • Classical conditioning forms associations between stimuli (a CS and the US it signals). It also involves respondent behavior —actions that are automatic responses to a stimulus (such as salivating in response to meat powder and later in response to a tone). • In operant conditioning, organisms associate their own actions with consequences. Actions followed by reinforcers increase; those followed by punishers decrease. Behavior that operates on the environment to produce rewarding or punishing stimuli is called operant behavior . In operant conditioning, an organism learns associations between its own behavior and resulting events; this form of conditioning involves operant behavior ( behavior that operates on the environment, producing consequences). In classical conditioning, the organism forms associations between stimuli— behaviors it does not control; this form of conditioning involves respondent behavior (automatic responses to some stimulus). Expanding on Edward Thorndike’s law of effect, B. F. Skinner and others found that the behavior of rats or pigeons placed in an operant chamber (Skinner box) can be shaped by using reinforcers to guide closer and closer approximations of the desired behavior . Through operant conditioning, organisms learn to produce behaviors that are followed by reinforcing stimuli and to suppress behaviors that are followed by punishing stimuli. Positive reinforcement adds something desirable to increase the frequency of a behavior . Negative reinforcement removes something undesirable to increase the frequency of a behavior . Primary reinforcers (such as receiving food when hungry or having nausea end during an illness) are innately satisfying—no learning is required. Conditioned (or secondary) reinforcers (such as cash) are satisfying because we have learned to associate them with more basic rewards (such as the food or medicine we buy with them). Immediate reinforcers (such as unprotected sex) offer immediate payback; delayed reinforcers (such as a weekly paycheck ) require the ability to delay gratification. In continuous reinforcement (reinforcing desired responses every time they occur), learning is rapid, but so is extinction if rewards cease. In partial (intermittent) reinforcement, initial learning is slower, but the behavior is much more resistant to extinction. Fixed-ratio schedules offer rewards after a set number of responses; variable-ratio schedules, after an unpredictable number. Fixed-interval schedules offer rewards after set time periods; variable-interval schedules, after unpredictable time periods. Punishment attempts to decrease the frequency of a behavior (a child’s disobedience) by administering an undesirable consequence (such as spanking) or withdrawing something desirable (such as taking away a favorite toy). Undesirable side effects can include suppressing rather than changing unwanted behaviors , teaching aggression, creating fear, encouraging discrimination (so that the undesirable behavior appears when the punisher is not present), and fostering depression and feelings of helplessness. Skinner underestimated the limits that cognitive and biological constraints place on conditioning. Research on cognitive mapping and latent learning demonstrate the importance of cognitive processes in learning. Excessive rewards can undermine intrinsic motivation. Training that attempts to override biological constraints will probably not endure because the animals will revert to their predisposed patterns. In school, teachers can use shaping techniques to guide students’ behaviors , and they can use interactive software and Web sites to provide immediate feedback. In sports, coaches can build players’ skills and self-confidence by rewarding small improvements. At work, managers can boost productivity and morale by rewarding well-defined and achievable behaviors . At home, parents can reward behaviors they consider desirable, but not those that are undesirable. We can shape our own behaviors by stating our goals, monitoring the frequency of desired behaviors , reinforcing desired behaviors , and cutting back on incentives as behaviors become habitual. Skinner’s Experiments. B. F. Skinner (1904–1990) was a college English major and an aspiring writer who, seeking a new direction, entered graduate school in psychology. He went on to become modern behaviorism’s most influential and controversial figure. Skinner’s work elaborated what psychologist Edward L. Thorndike called the law of effect: Rewarded behavior is likely to recur. Using Thorndike’s law of effect as a starting point, Skinner developed a behavioral technology that revealed principles of behavior control. These principles also enabled him to teach pigeons such unpigeonlike behaviors as walking in a figure 8, playing Ping-Pong, and keeping a missile on course by pecking at a screen target. For his pioneering studies, Skinner designed an operant chamber, popularly known as a Skinner box. The box has a bar or key that an animal presses or pecks to release a reward of food or water, and a device that records these responses. Operant conditioning experiments have done far more than teach us how to pull habits out of a rat. They have explored the precise conditions that foster efficient and enduring learning. Shaping Behavior In his experiments, Skinner used shaping, a procedure in which reinforcers , such as food, gradually guide an animal’s actions toward a desired behavior . Imagine that you wanted to condition a hungry rat to press a bar. First, you would watch how the animal naturally behaves, so that you could build on its existing behaviors . You might give the rat a food reward each time it approaches the bar. Once the rat is approaching regularly, you would require it to move closer before rewarding it, then closer still. Finally, you would require it to touch the bar before you gave it the food. With this method of successive approximations, you reward responses that are ever-closer to the final desired behavior , and you ignore all other responses. By making rewards contingent on desired behaviors , researchers and animal trainers gradually shape complex behaviors . Skinner showed that when placed in an operant chamber, rats or pigeons can be shaped to display successively closer approximations of a desired behavior . Researchers have also studied the effects of primary and secondary reinforcers , and of immediate and delayed reinforcers . Partial reinforcement schedules (fixed-ratio, variable-ratio, fixed-interval, and variable-interval) produce slower acquisition of the target behavior than does continuous reinforcement, but they also create more resistance to extinction. Punishment is most effective when it is strong, immediate, and consistent. However, it can have undesirable side effects. Shaping can also help us understand what nonverbal organisms perceive. Can a dog distinguish red and green? Can a baby hear the difference between lower- and higher-pitched tones? If we can shape them to respond to one stimulus and not to another, then we know they can perceive the difference. Such experiments have even shown that some animals can form concepts. If an experimenter reinforces a pigeon for pecking after seeing a human face, but not after seeing other images, the pigeon learns to recognize human faces. In this experiment, a face is a discriminative stimulus; like a green traffic light, it signals that a response will be reinforced. After being trained to discriminate among flowers, people, cars, and chairs, pigeons can usually identify the category in which a new pictured object belongs. They have even been trained to discriminate between Bach’s music and Stravinsky’s. Extending Skinner’s Understanding . Skinner’s emphasis on external control of behavior made him both influential and controversial. Many psychologists criticized Skinner (as they did Pavlov) for underestimating the importance of cognitive and biological constraints. For example, research on latent learning and motivation, both intrinsic and extrinsic, further indicates the importance of cognition in learning. Skinner and his collaborators compared four schedules of partial reinforcement. Some are rigidly fixed, some unpredictably variable. Fixed-ratio schedules reinforce behavior after a set number of responses. Just as coffee shops reward us with a free drink after every 10 purchased, laboratory animals may be reinforced on a fixed ratio of, say, one reinforcer for every 30 responses. Once conditioned, the animal will pause only briefly after a reinforcer and will then return to a high rate of responding. Variable-ratio schedules provide reinforcers after an unpredictable number of responses. This is what slot-machine players and fly-casting anglers experience—unpredictable reinforcement—and what makes gambling and fly fishing so hard to extinguish even when both are getting nothing for something. Like the fixed-ratio schedule, the variable-ratio schedule produces high rates of responding, because reinforcers increase as the number of responses increases. Fixed-interval schedules reinforce the first response after a fixed time period. Like people checking more frequently for the mail as the delivery time approaches, or checking to see if the Jell-O has set, pigeons on a fixed-interval schedule peck a key more frequently as the anticipated time for reward draws near, producing a choppy stop-start pattern rather than a steady rate of response. Variable-interval schedules reinforce the first response after varying time intervals. Like the “You’ve got mail” that finally rewards persistence in rechecking for e-mail, variable-interval schedules tend to produce slow, steady responding. This makes sense, because there is no knowing when the waiting will be over. Animal behaviors differ, yet Skinner contended that the reinforcement principles of operant conditioning are universal. It matters little, he said, what response, what reinforcer , or what species you use. The effect of a given reinforcement schedule is pretty much the same: “Pigeon, rat, monkey, which is which? It doesn’t matter. Behavior shows astonishingly similar properties.” Skinner’s Legacy. Skinner’s ideas that operant principles should be used to influence people were extremely controversial. Critics felt he ignored personal freedoms and sought to control people. Today, his techniques are applied in schools, sports, workplaces, and homes. Shaping behavior by reinforcing successes is effective. Learning by Observation. In observational learning, we observe and imitate others. Mirror neurons, located in the brain’s frontal lobes, demonstrate a neural basis for observational learning. They fire when we perform certain actions (such as responding to pain or moving our mouth to form words), or when we observe someone else performing those actions. Another important type of learning, especially among humans, is what Albert Bandura and others call observational learning. In experiments, children tend to imitate what a model both does and says, whether the behavior is social or antisocial. Such experiments have stimulated research on social modeling in the home, within peer groups, and in the media. Children are especially likely to imitate those they perceive to be like them, successful, or admirable. Mirror Neurons in the Brain. Having earlier observed the same weird result when the monkey watched humans or other monkeys move peanuts to their mouths, the flabbergasted researchers, led by Giacomo Rizzolatti , eventually surmised that they had stumbled onto a previously unknown type of neuron: mirror neurons, whose activity provides a neural basis for imitation and observational learning. When a monkey grasps, holds, or tears something, these neurons fire. And they likewise fire when the monkey observes another doing so. When one monkey sees, these neurons mirror what another monkey does. Imitation shapes even very young humans’ behavior . Shortly after birth, a baby may imitate an adult who sticks out his tongue. By 8 to 16 months, infants imitate various novel gestures. By age 12 months, they begin looking where an adult is looking. And by age 14 months, children imitate acts modeled on TV. Children see, children do. PET scans of different brain areas reveal that humans, like monkeys, have a mirror neuron system that supports empathy and imitation. As we observe another’s action, our brain generates an inner simulation, enabling us to experience the other’s experience within ourselves. Mirror neurons help give rise to children’s empathy and to their ability to infer another’s mental state, an ability known as theory of mind. People with autism display reduced imitative yawning and mirror neuron activity—“broken mirrors,” some have said. Bandura’s Experiments. Albert Bandura is the pioneering researcher of observational learning. A preschool child works on a drawing. An adult in another part of the room is building with Tinkertoys . As the child watches, the adult gets up and for nearly 10 minutes pounds, kicks, and throws around the room a large inflated Bobo doll, yelling, “Sock him in the nose. . . . Hit him down. . . . Kick him.” The child is then taken to another room filled with appealing toys. Soon the experimenter returns and tells the child she has decided to save these good toys “for the other children.” She takes the now-frustrated child to a third adjacent room containing a few toys, including a Bobo doll. Left alone, what does the child do? Compared with children not exposed to the adult model, those who viewed the model’s actions were much more likely to lash out at the doll. Apparently, observing the aggressive outburst lowered their inhibitions. But something more was also at work, for the children imitated the very acts they had observed and used the very words they had heard. Applications of Observational Learning. Children tend to imitate what a model does and says, whether the behavior being modeled is prosocial (positive, constructive, and helpful) or antisocial. If a model’s actions and words are inconsistent, children may imitate the hypocrisy they observe. The big news from Bandura’s studies is that we look and we learn. Models—in one’s family or neighborhood , or on TV—may have effects—good or bad. Many business organizations effectively use behavior modeling to train communications, sales, and customer service skills (Taylor et al., 2005). Trainees gain skills faster when they not only are told the needed skills but also are able to observe the skills being modeled effectively by experienced workers (or actors simulating them). The good news is that prosocial (positive, helpful) models can have prosocial effects. To encourage children to read, read to them and surround them with books and people who read. To increase the odds that your children will practice your religion, worship and attend religious activities with them. People who exemplify nonviolent, helpful behavior can prompt similar behavior in others. The bad news is that observational learning may have antisocial effects. This helps us understand why abusive parents might have aggressive children, and why many men who beat their wives had wife-battering fathers ( Stith et al., 2000). Critics note that being aggressive could be passed along by parents’ genes. The violence-viewing effect seems to stem from at least two factors. One is imitation. As we noted earlier, children as young as 14 months will imitate acts they observe on TV. As they watch, their mirror neurons simulate the behavior , and after this inner rehearsal they become more likely to act it out. rolonged exposure to violence also desensitizes viewers; they become more indifferent to it when later viewing a brawl, whether on TV or in real life.
MECHANISMS OF LEARNING Learning Learning is a relatively permanent change in an organism’s behavior due to experience. In associative learning, we learn to associate two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning). In observational learning, we learn by watching others’ experiences and examples. Learned associations also feed our habitual behaviors . As we repeat behaviors in a given context—the sleeping posture we associate with bed, our walking routes on campus, our eating popcorn in a movie theater —the behaviors become associated with the contexts. Our next experience of the context then automatically triggers the habitual response. Such associations can make it hard to kick a smoking habit; when back in the smoking context, the urge to light up can be powerful. By linking two events that occur close together, both the sea slug and the seals exhibit associative learning. The sea slug associates the squirt with an impending shock; the seal associates slapping and barking with a herring treat. Each animal has learned something important to its survival: predicting the immediate future. Conditioning is the process of learning associations. In classical conditioning, we learn to associate two stimuli and thus to anticipate events. We learn that a flash of lightning signals an impending crack of thunder, so when lightning flashes nearby, we start to brace ourselves. In operant conditioning, we learn to associate a response (our behavior ) and its consequence and thus to repeat acts followed by good results and avoid acts followed by bad results. Conditioning is not the only form of learning. Through observational learning, we learn from others’ experiences. Chimpanzees, too, may learn behaviors merely by watching others perform them. If one sees another solve a puzzle and gain a food reward, the observer may perform the trick more quickly. By conditioning and by observation we humans learn and adapt to our environments. We learn to expect and prepare for significant events such as food or pain (classical conditioning). We also learn to repeat acts that bring good results and to avoid acts that bring bad results (operant conditioning). By watching others we learn new behaviors (observational learning). And through language, we also learn things we have neither experienced nor observed. Classical Conditioning. Classical conditioning is a type of learning in which an organism comes to associate stimuli. Pavlov’s work on classical conditioning laid the foundation for behaviorism , the view that psychology should be an objective science that studies behavior without reference to mental processes. Although learning by association had been discussed for centuries, it remained for Ivan Pavlov to capture the phenomenon in his classic experiments on conditioning. In classical conditioning, a unconditional reflex (UR) is an event that occurs naturally (such as salivation), in response to some stimulus. A unconditional stimulus (US) is something that naturally and automatically (without learning) triggers the unlearned response (as food in the mouth triggers salivation). A conditional stimulus (CS) is a previously irrelevant stimulus (such as a bell) that, through learning, comes to be associated with some unlearned response (salivating). A conditional reflex (CR) is the learned response (salivating) to the originally irrelevant but now conditioned stimulus. In classical conditioning, acquisition is associating a CS with the US. Acquisition occurs most readily when a CS is presented just before (ideally, about a half-second before) a US, preparing the organism for the upcoming event. This finding supports the view that classical conditioning is biologically adaptive. Extinction is diminished responding when the CS no longer signals an impending US. Spontaneous recovery is the appearance of a formerly extinguished response, following a rest period. Generalization is the tendency to respond to stimuli that are similar to a CS. Discrimination is the learned ability to distinguish between a CS and other irrelevant stimuli. The behaviorists’ optimism that in any species, any response can be conditioned to any stimulus has been tempered. Conditioning principles, we now know, are cognitively and biologically constrained. In classical conditioning, animals learn when to expect a US, and they may be aware of the link between stimuli and responses. Moreover, because of biological predispositions, learning some associations is easier than learning others. Learning is adaptive: Each species learns behaviors that aid its survival. Pavlov taught us that significant psychological phenomena can be studied objectively, and that classical conditioning is a basic form of learning that applies to all species. Later research modified this finding somewhat by showing that in many species cognition and biological predispositions place some limits on conditioning. Classical conditioning techniques are used in treatment programs for those recovering from cocaine and other drug abuse and to condition more appropriate responses in therapy for emotional disorders. The body’s immune system also appears to respond to classical conditioning. Pavlov’s Experiments. Pavlov was driven by a lifelong passion for research. After setting aside his initial plan to follow his father into the Russian Orthodox priesthood, Pavlov received a medical degree at age 33 and spent the next two decades studying the digestive system. This work earned him Russia’s first Nobel prize in 1904. But it was his novel experiments on learning, to which he devoted the last three decades of his life, that earned this feisty scientist his place in history. Pavlov’s new direction came when his creative mind seized on an incidental observation. Without fail, putting food in a dog’s mouth caused the animal to salivate. Moreover, the dog began salivating not only to the taste of the food, but also to the mere sight of the food, or the food dish, or the person delivering the food, or even the sound of that person’s approaching footsteps. At first, Pavlov considered these “psychic secretions” an annoyance—until he realized they pointed to a simple but important form of learning. Pavlov and his assistants tried to imagine what the dog was thinking and feeling as it drooled in anticipation of the food. This only led them into fruitless debates. So, to explore the phenomenon more objectively, they experimented. To eliminate other possible influences, they isolated the dog in a small room, secured it in a harness, and attached a device to divert its saliva to a measuring instrument. From the next room, they presented food—first by sliding in a food bowl, later by blowing meat powder into the dog’s mouth at a precise moment. They then paired various neutral events—something the dog could see or hear but didn’t associate with food—with food in the dog’s mouth. If a sight or sound regularly signaled the arrival of food, would the dog learn the link? If so, would it begin salivating in anticipation of the food? The answers proved to be yes and yes. Just before placing food in the dog’s mouth to produce salivation, Pavlov sounded a tone. After several pairings of tone and food, the dog, anticipating the meat powder, began salivating to the tone alone. In later experiments, a buzzer, a light, a touch on the leg, even the sight of a circle set off the drooling. (This procedure works with people, too. When hungry young Londoners viewed abstract figures before smelling peanut butter or vanilla, their brains soon were responding in anticipation to the abstract images alone). Because salivation in response to food in the mouth was unlearned, Pavlov called it an unconditioned response (UR). Food in the mouth automatically, unconditionally, triggers a dog’s salivary reflex. Thus, Pavlov called the food stimulus an unconditioned stimulus (US). Pavlov repeatedly presented a neutral stimulus (such as a tone) just before an unconditioned stimulus (UCS, food) that triggered an unconditioned response (UCR, salivation). After several repetitions, the tone alone (now the conditioned stimulus, CS) triggered a conditioned response (CR, salivation). Further experiments on acquisition revealed that classical conditioning was usually greatest when the CS was presented just before the UCS, thus preparing the organism for what was coming. Other experiments explored the phenomena of acquisition, extinction, spontaneous recovery, generalization, and discrimination. Salivation in response to the tone was conditional upon the dog’s learning the association between the tone and the food. Today we call this learned response the conditioned response (CR). The previously neutral (in this context) tone stimulus that now triggered the conditional salivation we call the conditioned stimulus (CS). Distinguishing these two kinds of stimuli and responses is easy: Conditioned =learned; unconditioned = unlearned. Pavlov’s work laid a foundation for John B. Watson’s emerging belief that psychology, to be an objective science, should study only overt behavior , without considering unobservable mental activity. Watson called this position behaviorism . Extending Pavlov’s Understanding . The behaviorists’ optimism that learning principles would generalize from one response to another and from one species to another has been tempered. Conditioning principles, we now know, are cognitively influenced and biologically constrained. In classical conditioning, animals learn when to "expect" an unconditioned stimulus. Moreover, animals are biologically predisposed to learn associations between, say, a peculiar taste and a drink that will make them sick, which they will then avoid. They don’t, however, learn to avoid a sickening drink announced by a noise. To understand the acquisition, or initial learning, of the stimulus-response relationship, Pavlov and his associates had to confront the question of timing: How much time should elapse between presenting the neutral stimulus (the tone, the light, the touch) and the unconditioned stimulus? In most cases, not much—half a second usually works well. What do you suppose would happen if the food (US) appeared before the tone (CS) rather than after? Would conditioning occur? Not likely. With but a few exceptions, conditioning doesn’t happen when the CS follows the US. Remember, classical conditioning is biologically adaptive because it helps humans and other animals prepare for good or bad events. To Pavlov’s dogs, the tone (CS) signaled an important biological event—the arrival of food (US). To deer in the forest, the snapping of a twig (CS) may signal a predator’s approach (US). If the good or bad event had already occurred, the CS would not likely signal anything significant. Extinction and Spontaneous Recovery After conditioning, what happens if the CS occurs repeatedly without the US? Will the CS continue to elicit the CR? Pavlov discovered that when he sounded the tone again and again without presenting food, the dogs salivated less and less. Their declining salivation illustrates extinction , the diminished responding that occurs when the CS (tone) no longer signals an impending US (food). Pavlov found, however, that if he allowed several hours to elapse before sounding the tone again, the salivation to the tone would reappear spontaneously. This spontaneous recovery—the reappearance of a (weakened) CR after a pause—suggested to Pavlov that extinction was suppressing the CR rather than eliminating it. After breaking up with his fire-breathing heartthrob, Tirrell also experienced extinction and spontaneous recovery. He recalls that “the smell of onion breath (CS), no longer paired with the kissing (US), lost its ability to shiver my timbers. Occasionally, though, after not sensing the aroma for a long while, smelling onion breath awakens a small version of the emotional response I once felt.” Generalization Pavlov and his students noticed that a dog conditioned to the sound of one tone also responded somewhat to the sound of a different tone that had never been paired with food. Likewise, a dog conditioned to salivate when rubbed would also drool a bit when scratched or when touched on a different body part. This tendency to respond to stimuli similar to the CS is called generalization. Generalization can be adaptive, as when toddlers taught to fear moving cars also become afraid of moving trucks and motorcycles. So automatic is generalization that one Argentine writer who underwent torture still recoils with fear when he sees black shoes—his first glimpse of his torturers as they approached his cell. Generalization of anxiety reactions has been demonstrated in laboratory studies comparing abused with nonabused children. Shown an angry face on a computer screen, abused children’s brain-wave responses are dramatically stronger and longer lasting. Because of generalization, stimuli similar to naturally disgusting or appealing objects will, by association, evoke some disgust or liking. Normally desirable foods, such as fudge, are unappealing when shaped to resemble dog feces . Adults with childlike facial features (round face, large forehead, small chin, large eyes) are perceived as having childlike warmth, submissiveness, and naiveté. In both cases, people’s emotional reactions to one stimulus generalize to similar stimuli. Discrimination Pavlov’s dogs also learned to respond to the sound of a particular tone and not to other tones. Discrimination is the learned ability to distinguish between a conditioned stimulus (which predicts the US) and other irrelevant stimuli. Being able to recognize differences is adaptive. Slightly different stimuli can be followed by vastly different consequences. Confronted by a pit bull, your heart may race; confronted by a golden retriever, it probably will not. Pavlov’s Legacy. Pavlov taught us that principles of learning apply across species that significant psychological phenomena can be studied objectively, and that conditioning principles have important practical applications. Through higher-order conditioning, a new neutral stimulus can become a new conditioned stimulus. All that’s required is for it to become associated with a previously conditioned stimulus. If a tone regularly signals food and produces salivation, then a light that becomes associated with the tone may also begin to trigger salivation. Although this higher-order conditioning (also called second-order conditioning) tends to be weaker than first-stage conditioning, it influences our everyday lives. Imagine that something makes us very afraid (perhaps a pit bull dog associated with a previous dog bite). If something else, such as the sound of a barking dog, brings to mind that pit bull, the bark alone may make us feel a little afraid. Associations can influence attitudes. As Andy Field showed British children novel cartoon characters alongside either ice cream (Yum!) or Brussels sprouts (Yuk!), the children came to like best the ice-cream–associated characters. Michael Olson and Russell Fazio classically conditioned adults’ attitudes, using little-known Pokémon characters. The participants, playing the role of a security guard monitoring a video screen, viewed a stream of words, images, and Pokémon characters. Their task, they were told, was to respond to one target Pokémon character by pressing a button. Unnoticed by the participants, when two other Pokémon characters appeared on the screen, one was consistently associated with various positive words and images (such as awesome or a hot fudge sundae); the other appeared with negative words and images (such as awful or a cockroach). Without any conscious memory for the pairings, the participants formed more gut-level positive attitudes for the characters associated with the positive stimuli. Follow-up studies indicate that conditioned likes and dislikes are even stronger when people notice and are aware of the associations they have learned. Operant Conditioning. Classical conditioning and operant conditioning are both forms of associativelearning , yet their difference is straightforward: • Classical conditioning forms associations between stimuli (a CS and the US it signals). It also involves respondent behavior —actions that are automatic responses to a stimulus (such as salivating in response to meat powder and later in response to a tone). • In operant conditioning, organisms associate their own actions with consequences. Actions followed by reinforcers increase; those followed by punishers decrease. Behavior that operates on the environment to produce rewarding or punishing stimuli is called operant behavior . In operant conditioning, an organism learns associations between its own behavior and resulting events; this form of conditioning involves operant behavior ( behavior that operates on the environment, producing consequences). In classical conditioning, the organism forms associations between stimuli— behaviors it does not control; this form of conditioning involves respondent behavior (automatic responses to some stimulus). Expanding on Edward Thorndike’s law of effect, B. F. Skinner and others found that the behavior of rats or pigeons placed in an operant chamber (Skinner box) can be shaped by using reinforcers to guide closer and closer approximations of the desired behavior . Through operant conditioning, organisms learn to produce behaviors that are followed by reinforcing stimuli and to suppress behaviors that are followed by punishing stimuli. Positive reinforcement adds something desirable to increase the frequency of a behavior . Negative reinforcement removes something undesirable to increase the frequency of a behavior . Primary reinforcers (such as receiving food when hungry or having nausea end during an illness) are innately satisfying—no learning is required. Conditioned (or secondary) reinforcers (such as cash) are satisfying because we have learned to associate them with more basic rewards (such as the food or medicine we buy with them). Immediate reinforcers (such as unprotected sex) offer immediate payback; delayed reinforcers (such as a weekly paycheck ) require the ability to delay gratification. In continuous reinforcement (reinforcing desired responses every time they occur), learning is rapid, but so is extinction if rewards cease. In partial (intermittent) reinforcement, initial learning is slower, but the behavior is much more resistant to extinction. Fixed-ratio schedules offer rewards after a set number of responses; variable-ratio schedules, after an unpredictable number. Fixed-interval schedules offer rewards after set time periods; variable-interval schedules, after unpredictable time periods. Punishment attempts to decrease the frequency of a behavior (a child’s disobedience) by administering an undesirable consequence (such as spanking) or withdrawing something desirable (such as taking away a favorite toy). Undesirable side effects can include suppressing rather than changing unwanted behaviors , teaching aggression, creating fear, encouraging discrimination (so that the undesirable behavior appears when the punisher is not present), and fostering depression and feelings of helplessness. Skinner underestimated the limits that cognitive and biological constraints place on conditioning. Research on cognitive mapping and latent learning demonstrate the importance of cognitive processes in learning. Excessive rewards can undermine intrinsic motivation. Training that attempts to override biological constraints will probably not endure because the animals will revert to their predisposed patterns. In school, teachers can use shaping techniques to guide students’ behaviors , and they can use interactive software and Web sites to provide immediate feedback. In sports, coaches can build players’ skills and self-confidence by rewarding small improvements. At work, managers can boost productivity and morale by rewarding well-defined and achievable behaviors . At home, parents can reward behaviors they consider desirable, but not those that are undesirable. We can shape our own behaviors by stating our goals, monitoring the frequency of desired behaviors , reinforcing desired behaviors , and cutting back on incentives as behaviors become habitual. Skinner’s Experiments. B. F. Skinner (1904–1990) was a college English major and an aspiring writer who, seeking a new direction, entered graduate school in psychology. He went on to become modern behaviorism’s most influential and controversial figure. Skinner’s work elaborated what psychologist Edward L. Thorndike called the law of effect: Rewarded behavior is likely to recur. Using Thorndike’s law of effect as a starting point, Skinner developed a behavioral technology that revealed principles of behavior control. These principles also enabled him to teach pigeons such unpigeonlike behaviors as walking in a figure 8, playing Ping-Pong, and keeping a missile on course by pecking at a screen target. For his pioneering studies, Skinner designed an operant chamber, popularly known as a Skinner box. The box has a bar or key that an animal presses or pecks to release a reward of food or water, and a device that records these responses. Operant conditioning experiments have done far more than teach us how to pull habits out of a rat. They have explored the precise conditions that foster efficient and enduring learning. Shaping Behavior In his experiments, Skinner used shaping, a procedure in which reinforcers , such as food, gradually guide an animal’s actions toward a desired behavior . Imagine that you wanted to condition a hungry rat to press a bar. First, you would watch how the animal naturally behaves, so that you could build on its existing behaviors . You might give the rat a food reward each time it approaches the bar. Once the rat is approaching regularly, you would require it to move closer before rewarding it, then closer still. Finally, you would require it to touch the bar before you gave it the food. With this method of successive approximations, you reward responses that are ever-closer to the final desired behavior , and you ignore all other responses. By making rewards contingent on desired behaviors , researchers and animal trainers gradually shape complex behaviors . Skinner showed that when placed in an operant chamber, rats or pigeons can be shaped to display successively closer approximations of a desired behavior . Researchers have also studied the effects of primary and secondary reinforcers , and of immediate and delayed reinforcers . Partial reinforcement schedules (fixed-ratio, variable-ratio, fixed-interval, and variable-interval) produce slower acquisition of the target behavior than does continuous reinforcement, but they also create more resistance to extinction. Punishment is most effective when it is strong, immediate, and consistent. However, it can have undesirable side effects. Shaping can also help us understand what nonverbal organisms perceive. Can a dog distinguish red and green? Can a baby hear the difference between lower- and higher-pitched tones? If we can shape them to respond to one stimulus and not to another, then we know they can perceive the difference. Such experiments have even shown that some animals can form concepts. If an experimenter reinforces a pigeon for pecking after seeing a human face, but not after seeing other images, the pigeon learns to recognize human faces. In this experiment, a face is a discriminative stimulus; like a green traffic light, it signals that a response will be reinforced. After being trained to discriminate among flowers, people, cars, and chairs, pigeons can usually identify the category in which a new pictured object belongs. They have even been trained to discriminate between Bach’s music and Stravinsky’s. Extending Skinner’s Understanding . Skinner’s emphasis on external control of behavior made him both influential and controversial. Many psychologists criticized Skinner (as they did Pavlov) for underestimating the importance of cognitive and biological constraints. For example, research on latent learning and motivation, both intrinsic and extrinsic, further indicates the importance of cognition in learning. Skinner and his collaborators compared four schedules of partial reinforcement. Some are rigidly fixed, some unpredictably variable. Fixed-ratio schedules reinforce behavior after a set number of responses. Just as coffee shops reward us with a free drink after every 10 purchased, laboratory animals may be reinforced on a fixed ratio of, say, one reinforcer for every 30 responses. Once conditioned, the animal will pause only briefly after a reinforcer and will then return to a high rate of responding. Variable-ratio schedules provide reinforcers after an unpredictable number of responses. This is what slot-machine players and fly-casting anglers experience—unpredictable reinforcement—and what makes gambling and fly fishing so hard to extinguish even when both are getting nothing for something. Like the fixed-ratio schedule, the variable-ratio schedule produces high rates of responding, because reinforcers increase as the number of responses increases. Fixed-interval schedules reinforce the first response after a fixed time period. Like people checking more frequently for the mail as the delivery time approaches, or checking to see if the Jell-O has set, pigeons on a fixed-interval schedule peck a key more frequently as the anticipated time for reward draws near, producing a choppy stop-start pattern rather than a steady rate of response. Variable-interval schedules reinforce the first response after varying time intervals. Like the “You’ve got mail” that finally rewards persistence in rechecking for e-mail, variable-interval schedules tend to produce slow, steady responding. This makes sense, because there is no knowing when the waiting will be over. Animal behaviors differ, yet Skinner contended that the reinforcement principles of operant conditioning are universal. It matters little, he said, what response, what reinforcer , or what species you use. The effect of a given reinforcement schedule is pretty much the same: “Pigeon, rat, monkey, which is which? It doesn’t matter. Behavior shows astonishingly similar properties.” Skinner’s Legacy. Skinner’s ideas that operant principles should be used to influence people were extremely controversial. Critics felt he ignored personal freedoms and sought to control people. Today, his techniques are applied in schools, sports, workplaces, and homes. Shaping behavior by reinforcing successes is effective. Learning by Observation. In observational learning, we observe and imitate others. Mirror neurons, located in the brain’s frontal lobes, demonstrate a neural basis for observational learning. They fire when we perform certain actions (such as responding to pain or moving our mouth to form words), or when we observe someone else performing those actions. Another important type of learning, especially among humans, is what Albert Bandura and others call observational learning. In experiments, children tend to imitate what a model both does and says, whether the behavior is social or antisocial. Such experiments have stimulated research on social modeling in the home, within peer groups, and in the media. Children are especially likely to imitate those they perceive to be like them, successful, or admirable. Mirror Neurons in the Brain. Having earlier observed the same weird result when the monkey watched humans or other monkeys move peanuts to their mouths, the flabbergasted researchers, led by Giacomo Rizzolatti , eventually surmised that they had stumbled onto a previously unknown type of neuron: mirror neurons, whose activity provides a neural basis for imitation and observational learning. When a monkey grasps, holds, or tears something, these neurons fire. And they likewise fire when the monkey observes another doing so. When one monkey sees, these neurons mirror what another monkey does. Imitation shapes even very young humans’ behavior . Shortly after birth, a baby may imitate an adult who sticks out his tongue. By 8 to 16 months, infants imitate various novel gestures. By age 12 months, they begin looking where an adult is looking. And by age 14 months, children imitate acts modeled on TV. Children see, children do. PET scans of different brain areas reveal that humans, like monkeys, have a mirror neuron system that supports empathy and imitation. As we observe another’s action, our brain generates an inner simulation, enabling us to experience the other’s experience within ourselves. Mirror neurons help give rise to children’s empathy and to their ability to infer another’s mental state, an ability known as theory of mind. People with autism display reduced imitative yawning and mirror neuron activity—“broken mirrors,” some have said. Bandura’s Experiments. Albert Bandura is the pioneering researcher of observational learning. A preschool child works on a drawing. An adult in another part of the room is building with Tinkertoys . As the child watches, the adult gets up and for nearly 10 minutes pounds, kicks, and throws around the room a large inflated Bobo doll, yelling, “Sock him in the nose. . . . Hit him down. . . . Kick him.” The child is then taken to another room filled with appealing toys. Soon the experimenter returns and tells the child she has decided to save these good toys “for the other children.” She takes the now-frustrated child to a third adjacent room containing a few toys, including a Bobo doll. Left alone, what does the child do? Compared with children not exposed to the adult model, those who viewed the model’s actions were much more likely to lash out at the doll. Apparently, observing the aggressive outburst lowered their inhibitions. But something more was also at work, for the children imitated the very acts they had observed and used the very words they had heard. Applications of Observational Learning. Children tend to imitate what a model does and says, whether the behavior being modeled is prosocial (positive, constructive, and helpful) or antisocial. If a model’s actions and words are inconsistent, children may imitate the hypocrisy they observe. The big news from Bandura’s studies is that we look and we learn. Models—in one’s family or neighborhood , or on TV—may have effects—good or bad. Many business organizations effectively use behavior modeling to train communications, sales, and customer service skills (Taylor et al., 2005). Trainees gain skills faster when they not only are told the needed skills but also are able to observe the skills being modeled effectively by experienced workers (or actors simulating them). The good news is that prosocial (positive, helpful) models can have prosocial effects. To encourage children to read, read to them and surround them with books and people who read. To increase the odds that your children will practice your religion, worship and attend religious activities with them. People who exemplify nonviolent, helpful behavior can prompt similar behavior in others. The bad news is that observational learning may have antisocial effects. This helps us understand why abusive parents might have aggressive children, and why many men who beat their wives had wife-battering fathers ( Stith et al., 2000). Critics note that being aggressive could be passed along by parents’ genes. The violence-viewing effect seems to stem from at least two factors. One is imitation. As we noted earlier, children as young as 14 months will imitate acts they observe on TV. As they watch, their mirror neurons simulate the behavior , and after this inner rehearsal they become more likely to act it out. rolonged exposure to violence also desensitizes viewers; they become more indifferent to it when later viewing a brawl, whether on TV or in real life.
Learning is a relatively permanent change in an organism’s behavior due to experience. In associative learning, we learn to associate two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning). In observational learning, we learn by watching others’ experiences and examples. Learned associations also feed our habitual behaviors . As we repeat behaviors in a given context—the sleeping posture we associate with bed, our walking routes on campus, our eating popcorn in a movie theater —the behaviors become associated with the contexts. Our next experience of the context then automatically triggers the habitual response. Such associations can make it hard to kick a smoking habit; when back in the smoking context, the urge to light up can be powerful. By linking two events that occur close together, both the sea slug and the seals exhibit associative learning. The sea slug associates the squirt with an impending shock; the seal associates slapping and barking with a herring treat. Each animal has learned something important to its survival: predicting the immediate future. Conditioning is the process of learning associations. In classical conditioning, we learn to associate two stimuli and thus to anticipate events. We learn that a flash of lightning signals an impending crack of thunder, so when lightning flashes nearby, we start to brace ourselves. In operant conditioning, we learn to associate a response (our behavior ) and its consequence and thus to repeat acts followed by good results and avoid acts followed by bad results.
Learning is a relatively permanent change in an organism’s behavior due to experience. In associative learning, we learn to associate two stimuli (as in classical conditioning) or a response and its consequences (as in operant conditioning). In observational learning, we learn by watching others’ experiences and examples. Learned associations also feed our habitual behaviors . As we repeat behaviors in a given context—the sleeping posture we associate with bed, our walking routes on campus, our eating popcorn in a movie theater —the behaviors become associated with the contexts. Our next experience of the context then automatically triggers the habitual response. Such associations can make it hard to kick a smoking habit; when back in the smoking context, the urge to light up can be powerful. By linking two events that occur close together, both the sea slug and the seals exhibit associative learning. The sea slug associates the squirt with an impending shock; the seal associates slapping and barking with a herring treat. Each animal has learned something important to its survival: predicting the immediate future. Conditioning is the process of learning associations. In classical conditioning, we learn to associate two stimuli and thus to anticipate events. We learn that a flash of lightning signals an impending crack of thunder, so when lightning flashes nearby, we start to brace ourselves. In operant conditioning, we learn to associate a response (our behavior ) and its consequence and thus to repeat acts followed by good results and avoid acts followed by bad results.
Conditioning is not the only form of learning. Through observational learning, we learn from others’ experiences. Chimpanzees, too, may learn behaviors merely by watching others perform them. If one sees another solve a puzzle and gain a food reward, the observer may perform the trick more quickly.
Conditioning is not the only form of learning. Through observational learning, we learn from others’ experiences. Chimpanzees, too, may learn behaviors merely by watching others perform them. If one sees another solve a puzzle and gain a food reward, the observer may perform the trick more quickly.
By conditioning and by observation we humans learn and adapt to our environments. We learn to expect and prepare for significant events such as food or pain (classical conditioning). We also learn to repeat acts that bring good results and to avoid acts that bring bad results (operant conditioning). By watching others we learn new behaviors (observational learning). And through language, we also learn things we have neither experienced nor observed.
By conditioning and by observation we humans learn and adapt to our environments. We learn to expect and prepare for significant events such as food or pain (classical conditioning). We also learn to repeat acts that bring good results and to avoid acts that bring bad results (operant conditioning). By watching others we learn new behaviors (observational learning). And through language, we also learn things we have neither experienced nor observed.
Classical conditioning is a type of learning in which an organism comes to associate stimuli. Pavlov’s work on classical conditioning laid the foundation for behaviorism , the view that psychology should be an objective science that studies behavior without reference to mental processes. Although learning by association had been discussed for centuries, it remained for Ivan Pavlov to capture the phenomenon in his classic experiments on conditioning.
Classical conditioning is a type of learning in which an organism comes to associate stimuli. Pavlov’s work on classical conditioning laid the foundation for behaviorism , the view that psychology should be an objective science that studies behavior without reference to mental processes. Although learning by association had been discussed for centuries, it remained for Ivan Pavlov to capture the phenomenon in his classic experiments on conditioning.
In classical conditioning, a unconditional reflex (UR) is an event that occurs naturally (such as salivation), in response to some stimulus. A unconditional stimulus (US) is something that naturally and automatically (without learning) triggers the unlearned response (as food in the mouth triggers salivation). A conditional stimulus (CS) is a previously irrelevant stimulus (such as a bell) that, through learning, comes to be associated with some unlearned response (salivating). A conditional reflex (CR) is the learned response (salivating) to the originally irrelevant but now conditioned stimulus.
In classical conditioning, a unconditional reflex (UR) is an event that occurs naturally (such as salivation), in response to some stimulus. A unconditional stimulus (US) is something that naturally and automatically (without learning) triggers the unlearned response (as food in the mouth triggers salivation). A conditional stimulus (CS) is a previously irrelevant stimulus (such as a bell) that, through learning, comes to be associated with some unlearned response (salivating). A conditional reflex (CR) is the learned response (salivating) to the originally irrelevant but now conditioned stimulus.
In classical conditioning, acquisition is associating a CS with the US. Acquisition occurs most readily when a CS is presented just before (ideally, about a half-second before) a US, preparing the organism for the upcoming event. This finding supports the view that classical conditioning is biologically adaptive. Extinction is diminished responding when the CS no longer signals an impending US. Spontaneous recovery is the appearance of a formerly extinguished response, following a rest period. Generalization is the tendency to respond to stimuli that are similar to a CS. Discrimination is the learned ability to distinguish between a CS and other irrelevant stimuli.
In classical conditioning, acquisition is associating a CS with the US. Acquisition occurs most readily when a CS is presented just before (ideally, about a half-second before) a US, preparing the organism for the upcoming event. This finding supports the view that classical conditioning is biologically adaptive. Extinction is diminished responding when the CS no longer signals an impending US. Spontaneous recovery is the appearance of a formerly extinguished response, following a rest period. Generalization is the tendency to respond to stimuli that are similar to a CS. Discrimination is the learned ability to distinguish between a CS and other irrelevant stimuli.
The behaviorists’ optimism that in any species, any response can be conditioned to any stimulus has been tempered. Conditioning principles, we now know, are cognitively and biologically constrained. In classical conditioning, animals learn when to expect a US, and they may be aware of the link between stimuli and responses. Moreover, because of biological predispositions, learning some associations is easier than learning others. Learning is adaptive: Each species learns behaviors that aid its survival.
The behaviorists’ optimism that in any species, any response can be conditioned to any stimulus has been tempered. Conditioning principles, we now know, are cognitively and biologically constrained. In classical conditioning, animals learn when to expect a US, and they may be aware of the link between stimuli and responses. Moreover, because of biological predispositions, learning some associations is easier than learning others. Learning is adaptive: Each species learns behaviors that aid its survival.
Pavlov taught us that significant psychological phenomena can be studied objectively, and that classical conditioning is a basic form of learning that applies to all species. Later research modified this finding somewhat by showing that in many species cognition and biological predispositions place some limits on conditioning.
Pavlov taught us that significant psychological phenomena can be studied objectively, and that classical conditioning is a basic form of learning that applies to all species. Later research modified this finding somewhat by showing that in many species cognition and biological predispositions place some limits on conditioning.
Classical conditioning techniques are used in treatment programs for those recovering from cocaine and other drug abuse and to condition more appropriate responses in therapy for emotional disorders. The body’s immune system also appears to respond to classical conditioning.
Classical conditioning techniques are used in treatment programs for those recovering from cocaine and other drug abuse and to condition more appropriate responses in therapy for emotional disorders. The body’s immune system also appears to respond to classical conditioning.
Pavlov was driven by a lifelong passion for research. After setting aside his initial plan to follow his father into the Russian Orthodox priesthood, Pavlov received a medical degree at age 33 and spent the next two decades studying the digestive system. This work earned him Russia’s first Nobel prize in 1904. But it was his novel experiments on learning, to which he devoted the last three decades of his life, that earned this feisty scientist his place in history.
Pavlov was driven by a lifelong passion for research. After setting aside his initial plan to follow his father into the Russian Orthodox priesthood, Pavlov received a medical degree at age 33 and spent the next two decades studying the digestive system. This work earned him Russia’s first Nobel prize in 1904. But it was his novel experiments on learning, to which he devoted the last three decades of his life, that earned this feisty scientist his place in history.
Pavlov’s new direction came when his creative mind seized on an incidental observation. Without fail, putting food in a dog’s mouth caused the animal to salivate. Moreover, the dog began salivating not only to the taste of the food, but also to the mere sight of the food, or the food dish, or the person delivering the food, or even the sound of that person’s approaching footsteps. At first, Pavlov considered these “psychic secretions” an annoyance—until he realized they pointed to a simple but important form of learning.
Pavlov’s new direction came when his creative mind seized on an incidental observation. Without fail, putting food in a dog’s mouth caused the animal to salivate. Moreover, the dog began salivating not only to the taste of the food, but also to the mere sight of the food, or the food dish, or the person delivering the food, or even the sound of that person’s approaching footsteps. At first, Pavlov considered these “psychic secretions” an annoyance—until he realized they pointed to a simple but important form of learning.
Pavlov and his assistants tried to imagine what the dog was thinking and feeling as it drooled in anticipation of the food. This only led them into fruitless debates. So, to explore the phenomenon more objectively, they experimented. To eliminate other possible influences, they isolated the dog in a small room, secured it in a harness, and attached a device to divert its saliva to a measuring instrument. From the next room, they presented food—first by sliding in a food bowl, later by blowing meat powder into the dog’s mouth at a precise moment. They then paired various neutral events—something the dog could see or hear but didn’t associate with food—with food in the dog’s mouth. If a sight or sound regularly signaled the arrival of food, would the dog learn the link? If so, would it begin salivating in anticipation of the food?
Pavlov and his assistants tried to imagine what the dog was thinking and feeling as it drooled in anticipation of the food. This only led them into fruitless debates. So, to explore the phenomenon more objectively, they experimented. To eliminate other possible influences, they isolated the dog in a small room, secured it in a harness, and attached a device to divert its saliva to a measuring instrument. From the next room, they presented food—first by sliding in a food bowl, later by blowing meat powder into the dog’s mouth at a precise moment. They then paired various neutral events—something the dog could see or hear but didn’t associate with food—with food in the dog’s mouth. If a sight or sound regularly signaled the arrival of food, would the dog learn the link? If so, would it begin salivating in anticipation of the food?
The answers proved to be yes and yes. Just before placing food in the dog’s mouth to produce salivation, Pavlov sounded a tone. After several pairings of tone and food, the dog, anticipating the meat powder, began salivating to the tone alone. In later experiments, a buzzer, a light, a touch on the leg, even the sight of a circle set off the drooling. (This procedure works with people, too. When hungry young Londoners viewed abstract figures before smelling peanut butter or vanilla, their brains soon were responding in anticipation to the abstract images alone).
The answers proved to be yes and yes. Just before placing food in the dog’s mouth to produce salivation, Pavlov sounded a tone. After several pairings of tone and food, the dog, anticipating the meat powder, began salivating to the tone alone. In later experiments, a buzzer, a light, a touch on the leg, even the sight of a circle set off the drooling. (This procedure works with people, too. When hungry young Londoners viewed abstract figures before smelling peanut butter or vanilla, their brains soon were responding in anticipation to the abstract images alone).
Because salivation in response to food in the mouth was unlearned, Pavlov called it an unconditioned response (UR). Food in the mouth automatically, unconditionally, triggers a dog’s salivary reflex. Thus, Pavlov called the food stimulus an unconditioned stimulus (US).
Because salivation in response to food in the mouth was unlearned, Pavlov called it an unconditioned response (UR). Food in the mouth automatically, unconditionally, triggers a dog’s salivary reflex. Thus, Pavlov called the food stimulus an unconditioned stimulus (US).
Pavlov repeatedly presented a neutral stimulus (such as a tone) just before an unconditioned stimulus (UCS, food) that triggered an unconditioned response (UCR, salivation). After several repetitions, the tone alone (now the conditioned stimulus, CS) triggered a conditioned response (CR, salivation). Further experiments on acquisition revealed that classical conditioning was usually greatest when the CS was presented just before the UCS, thus preparing the organism for what was coming. Other experiments explored the phenomena of acquisition, extinction, spontaneous recovery, generalization, and discrimination.
Pavlov repeatedly presented a neutral stimulus (such as a tone) just before an unconditioned stimulus (UCS, food) that triggered an unconditioned response (UCR, salivation). After several repetitions, the tone alone (now the conditioned stimulus, CS) triggered a conditioned response (CR, salivation). Further experiments on acquisition revealed that classical conditioning was usually greatest when the CS was presented just before the UCS, thus preparing the organism for what was coming. Other experiments explored the phenomena of acquisition, extinction, spontaneous recovery, generalization, and discrimination.
After several repetitions, the tone alone (now the conditioned stimulus, CS) triggered a conditioned response (CR, salivation).
Salivation in response to the tone was conditional upon the dog’s learning the association between the tone and the food. Today we call this learned response the conditioned response (CR). The previously neutral (in this context) tone stimulus that now triggered the conditional salivation we call the conditioned stimulus (CS). Distinguishing these two kinds of stimuli and responses is easy: Conditioned =learned; unconditioned = unlearned.
Salivation in response to the tone was conditional upon the dog’s learning the association between the tone and the food. Today we call this learned response the conditioned response (CR). The previously neutral (in this context) tone stimulus that now triggered the conditional salivation we call the conditioned stimulus (CS). Distinguishing these two kinds of stimuli and responses is easy: Conditioned =learned; unconditioned = unlearned.
Pavlov’s work laid a foundation for John B. Watson’s emerging belief that psychology, to be an objective science, should study only overt behavior , without considering unobservable mental activity. Watson called this position behaviorism .
Pavlov’s work laid a foundation for John B. Watson’s emerging belief that psychology, to be an objective science, should study only overt behavior , without considering unobservable mental activity. Watson called this position behaviorism .
The behaviorists’ optimism that learning principles would generalize from one response to another and from one species to another has been tempered. Conditioning principles, we now know, are cognitively influenced and biologically constrained. In classical conditioning, animals learn when to "expect" an unconditioned stimulus. Moreover, animals are biologically predisposed to learn associations between, say, a peculiar taste and a drink that will make them sick, which they will then avoid. They don’t, however, learn to avoid a sickening drink announced by a noise.
The behaviorists’ optimism that learning principles would generalize from one response to another and from one species to another has been tempered. Conditioning principles, we now know, are cognitively influenced and biologically constrained. In classical conditioning, animals learn when to "expect" an unconditioned stimulus. Moreover, animals are biologically predisposed to learn associations between, say, a peculiar taste and a drink that will make them sick, which they will then avoid. They don’t, however, learn to avoid a sickening drink announced by a noise.
To understand the acquisition, or initial learning, of the stimulus-response relationship, Pavlov and his associates had to confront the question of timing: How much time should elapse between presenting the neutral stimulus (the tone, the light, the touch) and the unconditioned stimulus? In most cases, not much—half a second usually works well.
To understand the acquisition, or initial learning, of the stimulus-response relationship, Pavlov and his associates had to confront the question of timing: How much time should elapse between presenting the neutral stimulus (the tone, the light, the touch) and the unconditioned stimulus? In most cases, not much—half a second usually works well.
What do you suppose would happen if the food (US) appeared before the tone (CS) rather than after? Would conditioning occur? Not likely. With but a few exceptions, conditioning doesn’t happen when the CS follows the US. Remember, classical conditioning is biologically adaptive because it helps humans and other animals prepare for good or bad events. To Pavlov’s dogs, the tone (CS) signaled an important biological event—the arrival of food (US). To deer in the forest, the snapping of a twig (CS) may signal a predator’s approach (US). If the good or bad event had already occurred, the CS would not likely signal anything significant.
What do you suppose would happen if the food (US) appeared before the tone (CS) rather than after? Would conditioning occur? Not likely. With but a few exceptions, conditioning doesn’t happen when the CS follows the US. Remember, classical conditioning is biologically adaptive because it helps humans and other animals prepare for good or bad events. To Pavlov’s dogs, the tone (CS) signaled an important biological event—the arrival of food (US). To deer in the forest, the snapping of a twig (CS) may signal a predator’s approach (US). If the good or bad event had already occurred, the CS would not likely signal anything significant.
After conditioning, what happens if the CS occurs repeatedly without the US? Will the CS continue to elicit the CR? Pavlov discovered that when he sounded the tone again and again without presenting food, the dogs salivated less and less. Their declining salivation illustrates extinction , the diminished responding that occurs when the CS (tone) no longer signals an impending US (food).
After conditioning, what happens if the CS occurs repeatedly without the US? Will the CS continue to elicit the CR? Pavlov discovered that when he sounded the tone again and again without presenting food, the dogs salivated less and less. Their declining salivation illustrates extinction , the diminished responding that occurs when the CS (tone) no longer signals an impending US (food).
Pavlov found, however, that if he allowed several hours to elapse before sounding the tone again, the salivation to the tone would reappear spontaneously. This spontaneous recovery—the reappearance of a (weakened) CR after a pause—suggested to Pavlov that extinction was suppressing the CR rather than eliminating it.
Pavlov found, however, that if he allowed several hours to elapse before sounding the tone again, the salivation to the tone would reappear spontaneously. This spontaneous recovery—the reappearance of a (weakened) CR after a pause—suggested to Pavlov that extinction was suppressing the CR rather than eliminating it.
After breaking up with his fire-breathing heartthrob, Tirrell also experienced extinction and spontaneous recovery. He recalls that “the smell of onion breath (CS), no longer paired with the kissing (US), lost its ability to shiver my timbers. Occasionally, though, after not sensing the aroma for a long while, smelling onion breath awakens a small version of the emotional response I once felt.”
After breaking up with his fire-breathing heartthrob, Tirrell also experienced extinction and spontaneous recovery. He recalls that “the smell of onion breath (CS), no longer paired with the kissing (US), lost its ability to shiver my timbers. Occasionally, though, after not sensing the aroma for a long while, smelling onion breath awakens a small version of the emotional response I once felt.”
Pavlov and his students noticed that a dog conditioned to the sound of one tone also responded somewhat to the sound of a different tone that had never been paired with food. Likewise, a dog conditioned to salivate when rubbed would also drool a bit when scratched or when touched on a different body part. This tendency to respond to stimuli similar to the CS is called generalization. Generalization can be adaptive, as when toddlers taught to fear moving cars also become afraid of moving trucks and motorcycles. So automatic is generalization that one Argentine writer who underwent torture still recoils with fear when he sees black shoes—his first glimpse of his torturers as they approached his cell.
Pavlov and his students noticed that a dog conditioned to the sound of one tone also responded somewhat to the sound of a different tone that had never been paired with food. Likewise, a dog conditioned to salivate when rubbed would also drool a bit when scratched or when touched on a different body part. This tendency to respond to stimuli similar to the CS is called generalization. Generalization can be adaptive, as when toddlers taught to fear moving cars also become afraid of moving trucks and motorcycles. So automatic is generalization that one Argentine writer who underwent torture still recoils with fear when he sees black shoes—his first glimpse of his torturers as they approached his cell.
Generalization of anxiety reactions has been demonstrated in laboratory studies comparing abused with nonabused children. Shown an angry face on a computer screen, abused children’s brain-wave responses are dramatically stronger and longer lasting. Because of generalization, stimuli similar to naturally disgusting or appealing objects will, by association, evoke some disgust or liking. Normally desirable foods, such as fudge, are unappealing when shaped to resemble dog feces . Adults with childlike facial features (round face, large forehead, small chin, large eyes) are perceived as having childlike warmth, submissiveness, and naiveté. In both cases, people’s emotional reactions to one stimulus generalize to similar stimuli.
Generalization of anxiety reactions has been demonstrated in laboratory studies comparing abused with nonabused children. Shown an angry face on a computer screen, abused children’s brain-wave responses are dramatically stronger and longer lasting. Because of generalization, stimuli similar to naturally disgusting or appealing objects will, by association, evoke some disgust or liking. Normally desirable foods, such as fudge, are unappealing when shaped to resemble dog feces . Adults with childlike facial features (round face, large forehead, small chin, large eyes) are perceived as having childlike warmth, submissiveness, and naiveté. In both cases, people’s emotional reactions to one stimulus generalize to similar stimuli.
Pavlov’s dogs also learned to respond to the sound of a particular tone and not to other tones. Discrimination is the learned ability to distinguish between a conditioned stimulus (which predicts the US) and other irrelevant stimuli. Being able to recognize differences is adaptive. Slightly different stimuli can be followed by vastly different consequences. Confronted by a pit bull, your heart may race; confronted by a golden retriever, it probably will not.
Pavlov’s dogs also learned to respond to the sound of a particular tone and not to other tones. Discrimination is the learned ability to distinguish between a conditioned stimulus (which predicts the US) and other irrelevant stimuli. Being able to recognize differences is adaptive. Slightly different stimuli can be followed by vastly different consequences. Confronted by a pit bull, your heart may race; confronted by a golden retriever, it probably will not.
Pavlov taught us that principles of learning apply across species that significant psychological phenomena can be studied objectively, and that conditioning principles have important practical applications.
Pavlov taught us that principles of learning apply across species that significant psychological phenomena can be studied objectively, and that conditioning principles have important practical applications.
Through higher-order conditioning, a new neutral stimulus can become a new conditioned stimulus. All that’s required is for it to become associated with a previously conditioned stimulus. If a tone regularly signals food and produces salivation, then a light that becomes associated with the tone may also begin to trigger salivation. Although this higher-order conditioning (also called second-order conditioning) tends to be weaker than first-stage conditioning, it influences our everyday lives.
Through higher-order conditioning, a new neutral stimulus can become a new conditioned stimulus. All that’s required is for it to become associated with a previously conditioned stimulus. If a tone regularly signals food and produces salivation, then a light that becomes associated with the tone may also begin to trigger salivation. Although this higher-order conditioning (also called second-order conditioning) tends to be weaker than first-stage conditioning, it influences our everyday lives.
Imagine that something makes us very afraid (perhaps a pit bull dog associated with a previous dog bite). If something else, such as the sound of a barking dog, brings to mind that pit bull, the bark alone may make us feel a little afraid.
Imagine that something makes us very afraid (perhaps a pit bull dog associated with a previous dog bite). If something else, such as the sound of a barking dog, brings to mind that pit bull, the bark alone may make us feel a little afraid.
Associations can influence attitudes. As Andy Field showed British children novel cartoon characters alongside either ice cream (Yum!) or Brussels sprouts (Yuk!), the children came to like best the ice-cream–associated characters. Michael Olson and Russell Fazio classically conditioned adults’ attitudes, using little-known Pokémon characters. The participants, playing the role of a security guard monitoring a video screen, viewed a stream of words, images, and Pokémon characters. Their task, they were told, was to respond to one target Pokémon character by pressing a button. Unnoticed by the participants, when two other Pokémon characters appeared on the screen, one was consistently associated with various positive words and images (such as awesome or a hot fudge sundae); the other appeared with negative words and images (such as awful or a cockroach). Without any conscious memory for the pairings, the participants formed more gut-level positive attitudes for the characters associated with the positive stimuli. Follow-up studies indicate that conditioned likes and dislikes are even stronger when people notice and are aware of the associations they have learned.
Associations can influence attitudes. As Andy Field showed British children novel cartoon characters alongside either ice cream (Yum!) or Brussels sprouts (Yuk!), the children came to like best the ice-cream–associated characters. Michael Olson and Russell Fazio classically conditioned adults’ attitudes, using little-known Pokémon characters. The participants, playing the role of a security guard monitoring a video screen, viewed a stream of words, images, and Pokémon characters. Their task, they were told, was to respond to one target Pokémon character by pressing a button. Unnoticed by the participants, when two other Pokémon characters appeared on the screen, one was consistently associated with various positive words and images (such as awesome or a hot fudge sundae); the other appeared with negative words and images (such as awful or a cockroach). Without any conscious memory for the pairings, the participants formed more gut-level positive attitudes for the characters associated with the positive stimuli. Follow-up studies indicate that conditioned likes and dislikes are even stronger when people notice and are aware of the associations they have learned.
Classical conditioning and operant conditioning are both forms of associativelearning , yet their difference is straightforward:
Classical conditioning and operant conditioning are both forms of associativelearning , yet their difference is straightforward:
• Classical conditioning forms associations between stimuli (a CS and the US it signals). It also involves respondent behavior —actions that are automatic responses to a stimulus (such as salivating in response to meat powder and later in response to a tone).
• Classical conditioning forms associations between stimuli (a CS and the US it signals). It also involves respondent behavior —actions that are automatic responses to a stimulus (such as salivating in response to meat powder and later in response to a tone).
• In operant conditioning, organisms associate their own actions with consequences. Actions followed by reinforcers increase; those followed by punishers decrease. Behavior that operates on the environment to produce rewarding or punishing stimuli is called operant behavior .
• In operant conditioning, organisms associate their own actions with consequences. Actions followed by reinforcers increase; those followed by punishers decrease. Behavior that operates on the environment to produce rewarding or punishing stimuli is called operant behavior .
In operant conditioning, an organism learns associations between its own behavior and resulting events; this form of conditioning involves operant behavior ( behavior that operates on the environment, producing consequences). In classical conditioning, the organism forms associations between stimuli— behaviors it does not control; this form of conditioning involves respondent behavior (automatic responses to some stimulus).
In operant conditioning, an organism learns associations between its own behavior and resulting events; this form of conditioning involves operant behavior ( behavior that operates on the environment, producing consequences). In classical conditioning, the organism forms associations between stimuli— behaviors it does not control; this form of conditioning involves respondent behavior (automatic responses to some stimulus).
Expanding on Edward Thorndike’s law of effect, B. F. Skinner and others found that the behavior of rats or pigeons placed in an operant chamber (Skinner box) can be shaped by using reinforcers to guide closer and closer approximations of the desired behavior . Through operant conditioning, organisms learn to produce behaviors that are followed by reinforcing stimuli and to suppress behaviors that are followed by punishing stimuli.
Expanding on Edward Thorndike’s law of effect, B. F. Skinner and others found that the behavior of rats or pigeons placed in an operant chamber (Skinner box) can be shaped by using reinforcers to guide closer and closer approximations of the desired behavior . Through operant conditioning, organisms learn to produce behaviors that are followed by reinforcing stimuli and to suppress behaviors that are followed by punishing stimuli.
Positive reinforcement adds something desirable to increase the frequency of a behavior . Negative reinforcement removes something undesirable to increase the frequency of a behavior . Primary reinforcers (such as receiving food when hungry or having nausea end during an illness) are innately satisfying—no learning is required. Conditioned (or secondary) reinforcers (such as cash) are satisfying because we have learned to associate them with more basic rewards (such as the food or medicine we buy with them). Immediate reinforcers (such as unprotected sex) offer immediate payback; delayed reinforcers (such as a weekly paycheck ) require the ability to delay gratification.
Positive reinforcement adds something desirable to increase the frequency of a behavior . Negative reinforcement removes something undesirable to increase the frequency of a behavior . Primary reinforcers (such as receiving food when hungry or having nausea end during an illness) are innately satisfying—no learning is required. Conditioned (or secondary) reinforcers (such as cash) are satisfying because we have learned to associate them with more basic rewards (such as the food or medicine we buy with them). Immediate reinforcers (such as unprotected sex) offer immediate payback; delayed reinforcers (such as a weekly paycheck ) require the ability to delay gratification.
In continuous reinforcement (reinforcing desired responses every time they occur), learning is rapid, but so is extinction if rewards cease. In partial (intermittent) reinforcement, initial learning is slower, but the behavior is much more resistant to extinction. Fixed-ratio schedules offer rewards after a set number of responses; variable-ratio schedules, after an unpredictable number. Fixed-interval schedules offer rewards after set time periods; variable-interval schedules, after unpredictable time periods.
In continuous reinforcement (reinforcing desired responses every time they occur), learning is rapid, but so is extinction if rewards cease. In partial (intermittent) reinforcement, initial learning is slower, but the behavior is much more resistant to extinction. Fixed-ratio schedules offer rewards after a set number of responses; variable-ratio schedules, after an unpredictable number. Fixed-interval schedules offer rewards after set time periods; variable-interval schedules, after unpredictable time periods.
Punishment attempts to decrease the frequency of a behavior (a child’s disobedience) by administering an undesirable consequence (such as spanking) or withdrawing something desirable (such as taking away a favorite toy). Undesirable side effects can include suppressing rather than changing unwanted behaviors , teaching aggression, creating fear, encouraging discrimination (so that the undesirable behavior appears when the punisher is not present), and fostering depression and feelings of helplessness.
Punishment attempts to decrease the frequency of a behavior (a child’s disobedience) by administering an undesirable consequence (such as spanking) or withdrawing something desirable (such as taking away a favorite toy). Undesirable side effects can include suppressing rather than changing unwanted behaviors , teaching aggression, creating fear, encouraging discrimination (so that the undesirable behavior appears when the punisher is not present), and fostering depression and feelings of helplessness.
Skinner underestimated the limits that cognitive and biological constraints place on conditioning. Research on cognitive mapping and latent learning demonstrate the importance of cognitive processes in learning. Excessive rewards can undermine intrinsic motivation. Training that attempts to override biological constraints will probably not endure because the animals will revert to their predisposed patterns.
Skinner underestimated the limits that cognitive and biological constraints place on conditioning. Research on cognitive mapping and latent learning demonstrate the importance of cognitive processes in learning. Excessive rewards can undermine intrinsic motivation. Training that attempts to override biological constraints will probably not endure because the animals will revert to their predisposed patterns.
In school, teachers can use shaping techniques to guide students’ behaviors , and they can use interactive software and Web sites to provide immediate feedback. In sports, coaches can build players’ skills and self-confidence by rewarding small improvements. At work, managers can boost productivity and morale by rewarding well-defined and achievable behaviors . At home, parents can reward behaviors they consider desirable, but not those that are undesirable. We can shape our own behaviors by stating our goals, monitoring the frequency of desired behaviors , reinforcing desired behaviors , and cutting back on incentives as behaviors become habitual.
In school, teachers can use shaping techniques to guide students’ behaviors , and they can use interactive software and Web sites to provide immediate feedback. In sports, coaches can build players’ skills and self-confidence by rewarding small improvements. At work, managers can boost productivity and morale by rewarding well-defined and achievable behaviors . At home, parents can reward behaviors they consider desirable, but not those that are undesirable. We can shape our own behaviors by stating our goals, monitoring the frequency of desired behaviors , reinforcing desired behaviors , and cutting back on incentives as behaviors become habitual.
B. F. Skinner (1904–1990) was a college English major and an aspiring writer who, seeking a new direction, entered graduate school in psychology. He went on to become modern behaviorism’s most influential and controversial figure. Skinner’s work elaborated what psychologist Edward L. Thorndike called the law of effect: Rewarded behavior is likely to recur. Using Thorndike’s law of effect as a starting point, Skinner developed a behavioral technology that revealed principles of behavior control. These principles also enabled him to teach pigeons such unpigeonlike behaviors as walking in a figure 8, playing Ping-Pong, and keeping a missile on course by pecking at a screen target.
B. F. Skinner (1904–1990) was a college English major and an aspiring writer who, seeking a new direction, entered graduate school in psychology. He went on to become modern behaviorism’s most influential and controversial figure. Skinner’s work elaborated what psychologist Edward L. Thorndike called the law of effect: Rewarded behavior is likely to recur. Using Thorndike’s law of effect as a starting point, Skinner developed a behavioral technology that revealed principles of behavior control. These principles also enabled him to teach pigeons such unpigeonlike behaviors as walking in a figure 8, playing Ping-Pong, and keeping a missile on course by pecking at a screen target.
For his pioneering studies, Skinner designed an operant chamber, popularly known as a Skinner box. The box has a bar or key that an animal presses or pecks to release a reward of food or water, and a device that records these responses. Operant conditioning experiments have done far more than teach us how to pull habits out of a rat. They have explored the precise conditions that foster efficient and enduring learning.
For his pioneering studies, Skinner designed an operant chamber, popularly known as a Skinner box. The box has a bar or key that an animal presses or pecks to release a reward of food or water, and a device that records these responses. Operant conditioning experiments have done far more than teach us how to pull habits out of a rat. They have explored the precise conditions that foster efficient and enduring learning.
In his experiments, Skinner used shaping, a procedure in which reinforcers , such as food, gradually guide an animal’s actions toward a desired behavior . Imagine that you wanted to condition a hungry rat to press a bar. First, you would watch how the animal naturally behaves, so that you could build on its existing behaviors . You might give the rat a food reward each time it approaches the bar. Once the rat is approaching regularly, you would require it to move closer before rewarding it, then closer still.
In his experiments, Skinner used shaping, a procedure in which reinforcers , such as food, gradually guide an animal’s actions toward a desired behavior . Imagine that you wanted to condition a hungry rat to press a bar. First, you would watch how the animal naturally behaves, so that you could build on its existing behaviors . You might give the rat a food reward each time it approaches the bar. Once the rat is approaching regularly, you would require it to move closer before rewarding it, then closer still.
Finally, you would require it to touch the bar before you gave it the food. With this method of successive approximations, you reward responses that are ever-closer to the final desired behavior , and you ignore all other responses. By making rewards contingent on desired behaviors , researchers and animal trainers gradually shape complex behaviors .
Finally, you would require it to touch the bar before you gave it the food. With this method of successive approximations, you reward responses that are ever-closer to the final desired behavior , and you ignore all other responses. By making rewards contingent on desired behaviors , researchers and animal trainers gradually shape complex behaviors .
Skinner showed that when placed in an operant chamber, rats or pigeons can be shaped to display successively closer approximations of a desired behavior . Researchers have also studied the effects of primary and secondary reinforcers , and of immediate and delayed reinforcers . Partial reinforcement schedules (fixed-ratio, variable-ratio, fixed-interval, and variable-interval) produce slower acquisition of the target behavior than does continuous reinforcement, but they also create more resistance to extinction. Punishment is most effective when it is strong, immediate, and consistent. However, it can have undesirable side effects.
Skinner showed that when placed in an operant chamber, rats or pigeons can be shaped to display successively closer approximations of a desired behavior . Researchers have also studied the effects of primary and secondary reinforcers , and of immediate and delayed reinforcers . Partial reinforcement schedules (fixed-ratio, variable-ratio, fixed-interval, and variable-interval) produce slower acquisition of the target behavior than does continuous reinforcement, but they also create more resistance to extinction. Punishment is most effective when it is strong, immediate, and consistent. However, it can have undesirable side effects.
Shaping can also help us understand what nonverbal organisms perceive. Can a dog distinguish red and green? Can a baby hear the difference between lower- and higher-pitched tones? If we can shape them to respond to one stimulus and not to another, then we know they can perceive the difference. Such experiments have even shown that some animals can form concepts. If an experimenter reinforces a pigeon for pecking after seeing a human face, but not after seeing other images, the pigeon learns to recognize human faces. In this experiment, a face is a discriminative stimulus; like a green traffic light, it signals that a response will be reinforced. After being trained to discriminate among flowers, people, cars, and chairs, pigeons can usually identify the category in which a new pictured object belongs. They have even been trained to discriminate between Bach’s music and Stravinsky’s.
Shaping can also help us understand what nonverbal organisms perceive. Can a dog distinguish red and green? Can a baby hear the difference between lower- and higher-pitched tones? If we can shape them to respond to one stimulus and not to another, then we know they can perceive the difference. Such experiments have even shown that some animals can form concepts. If an experimenter reinforces a pigeon for pecking after seeing a human face, but not after seeing other images, the pigeon learns to recognize human faces. In this experiment, a face is a discriminative stimulus; like a green traffic light, it signals that a response will be reinforced. After being trained to discriminate among flowers, people, cars, and chairs, pigeons can usually identify the category in which a new pictured object belongs. They have even been trained to discriminate between Bach’s music and Stravinsky’s.
Skinner’s emphasis on external control of behavior made him both influential and controversial. Many psychologists criticized Skinner (as they did Pavlov) for underestimating the importance of cognitive and biological constraints. For example, research on latent learning and motivation, both intrinsic and extrinsic, further indicates the importance of cognition in learning.
Skinner’s emphasis on external control of behavior made him both influential and controversial. Many psychologists criticized Skinner (as they did Pavlov) for underestimating the importance of cognitive and biological constraints. For example, research on latent learning and motivation, both intrinsic and extrinsic, further indicates the importance of cognition in learning.
Skinner and his collaborators compared four schedules of partial reinforcement. Some are rigidly fixed, some unpredictably variable.
Skinner and his collaborators compared four schedules of partial reinforcement. Some are rigidly fixed, some unpredictably variable.
Fixed-ratio schedules reinforce behavior after a set number of responses. Just as coffee shops reward us with a free drink after every 10 purchased, laboratory animals may be reinforced on a fixed ratio of, say, one reinforcer for every 30 responses. Once conditioned, the animal will pause only briefly after a reinforcer and will then return to a high rate of responding.
reinforce behavior after a set number of responses. Just as coffee shops reward us with a free drink after every 10 purchased, laboratory animals may be reinforced on a fixed ratio of, say, one reinforcer for every 30 responses. Once conditioned, the animal will pause only briefly after a reinforcer and will then return to a high rate of responding.
Variable-ratio schedules provide reinforcers after an unpredictable number of responses. This is what slot-machine players and fly-casting anglers experience—unpredictable reinforcement—and what makes gambling and fly fishing so hard to extinguish even when both are getting nothing for something. Like the fixed-ratio schedule, the variable-ratio schedule produces high rates of responding, because reinforcers increase as the number of responses increases.
provide reinforcers after an unpredictable number of responses. This is what slot-machine players and fly-casting anglers experience—unpredictable reinforcement—and what makes gambling and fly fishing so hard to extinguish even when both are getting nothing for something. Like the fixed-ratio schedule, the variable-ratio schedule produces high rates of responding, because reinforcers increase as the number of responses increases.
Fixed-interval schedules reinforce the first response after a fixed time period. Like people checking more frequently for the mail as the delivery time approaches, or checking to see if the Jell-O has set, pigeons on a fixed-interval schedule peck a key more frequently as the anticipated time for reward draws near, producing a choppy stop-start pattern rather than a steady rate of response.
reinforce the first response after a fixed time period. Like people checking more frequently for the mail as the delivery time approaches, or checking to see if the Jell-O has set, pigeons on a fixed-interval schedule peck a key more frequently as the anticipated time for reward draws near, producing a choppy stop-start pattern rather than a steady rate of response.
Variable-interval schedules reinforce the first response after varying time intervals. Like the “You’ve got mail” that finally rewards persistence in rechecking for e-mail, variable-interval schedules tend to produce slow, steady responding. This makes sense, because there is no knowing when the waiting will be over.
reinforce the first response after varying time intervals. Like the “You’ve got mail” that finally rewards persistence in rechecking for e-mail, variable-interval schedules tend to produce slow, steady responding. This makes sense, because there is no knowing when the waiting will be over.
Animal behaviors differ, yet Skinner contended that the reinforcement principles of operant conditioning are universal. It matters little, he said, what response, what reinforcer , or what species you use. The effect of a given reinforcement schedule is pretty much the same: “Pigeon, rat, monkey, which is which? It doesn’t matter. Behavior shows astonishingly similar properties.”
Animal behaviors differ, yet Skinner contended that the reinforcement principles of operant conditioning are universal. It matters little, he said, what response, what reinforcer , or what species you use. The effect of a given reinforcement schedule is pretty much the same: “Pigeon, rat, monkey, which is which? It doesn’t matter. Behavior shows astonishingly similar properties.”
Skinner’s ideas that operant principles should be used to influence people were extremely controversial. Critics felt he ignored personal freedoms and sought to control people. Today, his techniques are applied in schools, sports, workplaces, and homes. Shaping behavior by reinforcing successes is effective.
Skinner’s ideas that operant principles should be used to influence people were extremely controversial. Critics felt he ignored personal freedoms and sought to control people. Today, his techniques are applied in schools, sports, workplaces, and homes. Shaping behavior by reinforcing successes is effective.
In observational learning, we observe and imitate others. Mirror neurons, located in the brain’s frontal lobes, demonstrate a neural basis for observational learning. They fire when we perform certain actions (such as responding to pain or moving our mouth to form words), or when we observe someone else performing those actions. Another important type of learning, especially among humans, is what Albert Bandura and others call observational learning. In experiments, children tend to imitate what a model both does and says, whether the behavior is social or antisocial. Such experiments have stimulated research on social modeling in the home, within peer groups, and in the media. Children are especially likely to imitate those they perceive to be like them, successful, or admirable.
In observational learning, we observe and imitate others. Mirror neurons, located in the brain’s frontal lobes, demonstrate a neural basis for observational learning. They fire when we perform certain actions (such as responding to pain or moving our mouth to form words), or when we observe someone else performing those actions. Another important type of learning, especially among humans, is what Albert Bandura and others call observational learning. In experiments, children tend to imitate what a model both does and says, whether the behavior is social or antisocial. Such experiments have stimulated research on social modeling in the home, within peer groups, and in the media. Children are especially likely to imitate those they perceive to be like them, successful, or admirable.
Having earlier observed the same weird result when the monkey watched humans or other monkeys move peanuts to their mouths, the flabbergasted researchers, led by Giacomo Rizzolatti , eventually surmised that they had stumbled onto a previously unknown type of neuron: mirror neurons, whose activity provides a neural basis for imitation and observational learning. When a monkey grasps, holds, or tears something, these neurons fire. And they likewise fire when the monkey observes another doing so. When one monkey sees, these neurons mirror what another monkey does.
Having earlier observed the same weird result when the monkey watched humans or other monkeys move peanuts to their mouths, the flabbergasted researchers, led by Giacomo Rizzolatti , eventually surmised that they had stumbled onto a previously unknown type of neuron: mirror neurons, whose activity provides a neural basis for imitation and observational learning. When a monkey grasps, holds, or tears something, these neurons fire. And they likewise fire when the monkey observes another doing so. When one monkey sees, these neurons mirror what another monkey does.
Imitation shapes even very young humans’ behavior . Shortly after birth, a baby may imitate an adult who sticks out his tongue. By 8 to 16 months, infants imitate various novel gestures. By age 12 months, they begin looking where an adult is looking. And by age 14 months, children imitate acts modeled on TV. Children see, children do. PET scans of different brain areas reveal that humans, like monkeys, have a mirror neuron system that supports empathy and imitation. As we observe another’s action, our brain generates an inner simulation, enabling us to experience the other’s experience within ourselves. Mirror neurons help give rise to children’s empathy and to their ability to infer another’s mental state, an ability known as theory of mind. People with autism display reduced imitative yawning and mirror neuron activity—“broken mirrors,” some have said.
Imitation shapes even very young humans’ behavior . Shortly after birth, a baby may imitate an adult who sticks out his tongue. By 8 to 16 months, infants imitate various novel gestures. By age 12 months, they begin looking where an adult is looking. And by age 14 months, children imitate acts modeled on TV. Children see, children do. PET scans of different brain areas reveal that humans, like monkeys, have a mirror neuron system that supports empathy and imitation. As we observe another’s action, our brain generates an inner simulation, enabling us to experience the other’s experience within ourselves. Mirror neurons help give rise to children’s empathy and to their ability to infer another’s mental state, an ability known as theory of mind. People with autism display reduced imitative yawning and mirror neuron activity—“broken mirrors,” some have said.
Albert Bandura is the pioneering researcher of observational learning. A preschool child works on a drawing. An adult in another part of the room is building with Tinkertoys . As the child watches, the adult gets up and for nearly 10 minutes pounds, kicks, and throws around the room a large inflated Bobo doll, yelling, “Sock him in the nose. . . . Hit him down. . . . Kick him.”
Albert Bandura is the pioneering researcher of observational learning. A preschool child works on a drawing. An adult in another part of the room is building with Tinkertoys . As the child watches, the adult gets up and for nearly 10 minutes pounds, kicks, and throws around the room a large inflated Bobo doll, yelling, “Sock him in the nose. . . . Hit him down. . . . Kick him.”
The child is then taken to another room filled with appealing toys. Soon the experimenter returns and tells the child she has decided to save these good toys “for the other children.” She takes the now-frustrated child to a third adjacent room containing a few toys, including a Bobo doll. Left alone, what does the child do?
The child is then taken to another room filled with appealing toys. Soon the experimenter returns and tells the child she has decided to save these good toys “for the other children.” She takes the now-frustrated child to a third adjacent room containing a few toys, including a Bobo doll. Left alone, what does the child do?
Compared with children not exposed to the adult model, those who viewed the model’s actions were much more likely to lash out at the doll. Apparently, observing the aggressive outburst lowered their inhibitions. But something more was also at work, for the children imitated the very acts they had observed and used the very words they had heard.
Compared with children not exposed to the adult model, those who viewed the model’s actions were much more likely to lash out at the doll. Apparently, observing the aggressive outburst lowered their inhibitions. But something more was also at work, for the children imitated the very acts they had observed and used the very words they had heard.
Children tend to imitate what a model does and says, whether the behavior being modeled is prosocial (positive, constructive, and helpful) or antisocial. If a model’s actions and words are inconsistent, children may imitate the hypocrisy they observe.
Children tend to imitate what a model does and says, whether the behavior being modeled is prosocial (positive, constructive, and helpful) or antisocial. If a model’s actions and words are inconsistent, children may imitate the hypocrisy they observe.
The big news from Bandura’s studies is that we look and we learn. Models—in one’s family or neighborhood , or on TV—may have effects—good or bad. Many business organizations effectively use behavior modeling to train communications, sales, and customer service skills (Taylor et al., 2005). Trainees gain skills faster when they not only are told the needed skills but also are able to observe the skills being modeled effectively by experienced workers (or actors simulating them).
The big news from Bandura’s studies is that we look and we learn. Models—in one’s family or neighborhood , or on TV—may have effects—good or bad. Many business organizations effectively use behavior modeling to train communications, sales, and customer service skills (Taylor et al., 2005). Trainees gain skills faster when they not only are told the needed skills but also are able to observe the skills being modeled effectively by experienced workers (or actors simulating them).
The good news is that prosocial (positive, helpful) models can have prosocial effects. To encourage children to read, read to them and surround them with books and people who read. To increase the odds that your children will practice your religion, worship and attend religious activities with them. People who exemplify nonviolent, helpful behavior can prompt similar behavior in others.
The good news is that prosocial (positive, helpful) models can have prosocial effects. To encourage children to read, read to them and surround them with books and people who read. To increase the odds that your children will practice your religion, worship and attend religious activities with them. People who exemplify nonviolent, helpful behavior can prompt similar behavior in others.
The bad news is that observational learning may have antisocial effects. This helps us understand why abusive parents might have aggressive children, and why many men who beat their wives had wife-battering fathers ( Stith et al., 2000). Critics note that being aggressive could be passed along by parents’ genes.
The bad news is that observational learning may have antisocial effects. This helps us understand why abusive parents might have aggressive children, and why many men who beat their wives had wife-battering fathers ( Stith et al., 2000). Critics note that being aggressive could be passed along by parents’ genes.
The violence-viewing effect seems to stem from at least two factors. One is imitation. As we noted earlier, children as young as 14 months will imitate acts they observe on TV. As they watch, their mirror neurons simulate the behavior , and after this inner rehearsal they become more likely to act it out. rolonged exposure to violence also desensitizes viewers; they become more indifferent to it when later viewing a brawl, whether on TV or in real life.
The violence-viewing effect seems to stem from at least two factors. One is imitation. As we noted earlier, children as young as 14 months will imitate acts they observe on TV. As they watch, their mirror neurons simulate the behavior , and after this inner rehearsal they become more likely to act it out. rolonged exposure to violence also desensitizes viewers; they become more indifferent to it when later viewing a brawl, whether on TV or in real life. | biology | 90629 | https://no.wikipedia.org/wiki/Behaviorisme | Behaviorisme | Behaviorisme er en psykologisk tilnærming der atferd defineres som psykologiens tema. Behaviorismen ble utviklet i USA tidlig på 1900-tallet som en reaksjon mot datidens bevissthetspsykologi. Viktige forløpere for behaviorismen var Ivan Pavlov, som påviste klassisk betinging og Edward Lee Thorndike som beskrev effektloven. Ingen av disse var imidlertid behaviorister. Den behavioristiske skolen startet i ca. 1910 med John B. Watson (1878–1958), som avviste introspektive metoder og argumenterte for å begrense psykologi til studiet av atferd. B.F. Skinner (1904–1990) inkluderte bevissthet og andre ikke-observerbare forhold, såkalte «private hendelser», i vitenskapelig analyse, og utviklet radikalbehaviorisme.
Behaviorismen var lenge en svært populær psykologisk tilnærming. Denne arven ses i dag ved at psykologien har en sterk forankring i atferd, både i sin definisjon og i fokus for forskning og praksis. I dag er atferdsperspektivet et av flere innenfor psykologien. Anvendt atferdsanalyse og atferdsterapi har etablert seg som viktige anvendte/kliniske intervensjonsformer.
Tilnærminger
Innen behaviorisme er det ulike tilnærminger som vektlegger forskjellige forhold. Noen behaviorister hevder at observerbar atferd er den eneste mulighet for å undersøke psykologiske fenomener. Andre mener at atferd i seg selv er det eneste riktige tema for psykologi, og at vanlige psykologiske termer som tro, tanke, hukommelse osv. bare viser til atferd. De siste omtaler ofte sitt studiefelt som atferdsanalyse eller atferdsvitenskap i stedet for psykologi.
Ulike former for behaviorisme
Dette er ikke allmenne klassifikasjoner, og listen er heller ikke uttømmende.
Klassisk behaviorisme er Watsons behaviorisme. Det er den objektive studien av atferd, uten mentale forklaringer og uten henvisninger til indre tilstander. Tanker fremstilles som "skjult" snakking.
Metodologisk behaviorisme er en atferdsorientert tilnærming der antatte medierende hjelpebegreper er viktig. Et eksempel er Tolmans kognitive kart.
Radikalbehaviorisme er en skinneriansk form for behaviorisme. Den har et atferdsperpektiv -- ikke et mekanistisk syn -- på «mentalt liv». Forklaringer ved å henvise til hypotetiske indre tilstander, forkastes.
Teleologisk behaviorisme: Post-Skinneriansk, purposive, close to microeconomics.
Teoretisk behaviorisme: Post-Skinneriansk, godtar observerbare indre tilstander; dynamisk, men eklektisk i valg av teoretiske strukturer, vektlegger parsimoni.
John B. Watson
John B. Watson (1878–1958) mente at det ikke var noen pålitelig måte å validere introspektive rapporter på, slik samtidige psykologer arbeidet med mennesker. Tidlig på 1900-tallet argumenterte Watson, i boken Psychology from the Standpoint of a Behaviorist for at psykologien skulle fokusere på observerbar atferd og ikke på bevissthet. Dette var et betydelig brudd med den «strukturelle» psykologien som hersket, som benyttet introspeksjon som metode og som anså studiet av atferd som betydningsløst. Watson studerte organismers tilpasning til miljøet, nærmere bestemt de enkelte stimuli som ledet organismer til responser. Det meste av Watsons arbeid var komparativ psykologi, m.a.o. studiet av dyrs atferd. Watsons tilnærming var i stor grad påvirket av arbeidet til den russiske fysiologen Ivan Pavlov som tilfeldig oppdaget fenomenet klassisk betinging (lærte reflekser) da han studerte fordøyelsen hos hunder, og deretter studerte fenomenet i detalj. Watsons tilnærming vektla fysiologi og stimulienes betydning i dannelse av betingede responser – han forklarte de fleste eller alle funksjoner med referanse til reflekser. Av den grunn beskrives Watson ofte som en S-R (stimulus-respons) psykolog.
Metodologisk behaviorisme
Watsons behavioristiske manifest overbeviste de fleste akademiske forskere innen eksperimentell psykologi om betydningen av å studere atferd. Det ble godt mottatt av forskere som blant annet Edward Thorndike (som hadde studert katters evne til å komme seg ut av «problembokser»). Men de fleste psykologer tok den stilling som nå kalles metodologisk behaviorisme; de anerkjente at atferd enten var den eneste eller den enkleste metode for observasjon innen psykologi, men mente at den kunne brukes for å trekke konklusjoner om modeller eller konstrukter som medierte relasjoner mellom stimulus (S) og respons (R). Blant mange velkjente behaviorister som tok denne stillingen var Clark L. Hull, som beskrev sin posisjon som «neo-behaviorisme», og Edward C. Tolman, som utviklet mye av det som senere ble til kognitiv psykologi. Tolman mente rotter dannet kognitive kart over labyrintene, at de lærte også fravær av forsterkning, og at relasjonen mellom stimulus og respons (S → R) ble mediert ved en tredje term - organismen (S → O → R).
Skinner og radikalbehaviorisme
B.F. Skinner, som hovedsakelig gjorde eksperimenter innen komparativ psykologi fra 1930-tallet frem til 1950-tallet, er fortsatt behaviorismens mest kjente teoretiker og den fremste eksponenten frem til sin død i 1990. Han stod for en egen behavioristisk filosofi, som kalles radikalbehaviorisme. Han er også anerkjent for å ha grunnlagt en ny form for psykologisk vitenskap, som er kjent som atferdsanalyse (behavior analysis) eller eksperimentell atferdsanalyse (experimental analysis of behavior) fra tittelen på boken fra 1938 The Behavior of Organism: An Experimental Analysis Of Behavior.
«Men act upon the world, and change it, and are changed in turn by the consequences of their action». B.F. Skinner (1957) Verbal Behavior, s. 1.
Definisjoner
Skinner hadde stor påvirkning på definisjonen av radikalbehaviorisme, en filosofi som danner grunnlaget for vitenskapelig analyse av atferd (eksperimentell atferdsanalyse, EA). Mens EA er annerledes enn andre tilnærminger til behavioristisk forskning, så er radikalbehaviorisme mest ulik ved at den godtar behandling av følelser, indre tilstander og introspeksjon (selv-rapportering) som eksisterende og vitenskapelig tilgjengelig. Dette kan gjøres ved å identifisere fenomenet som ikke-dualistisk, med noen hendelser som kroppslige tilstander og andre som komplisert atferd. Men, radikalbehaviorisme godtar ikke følelser som årsak til atferd. Radikalbehaviorismen skiller seg også ut ved at den ikke aksepterer reflekser som en modell for all atferd, og den ser på atferdsvitenskap som komplimentær men uavhengig av fysiologi.
Eksperimentelle og konseptuelle nyvinninger
Denne essensielle filosofiske posisjon ble styrket ved suksessen til Skinners tidlige eksperimentelle arbeid med rotter og duer, bl.a. oppsummert i bøkene The Behavior of Organisms (1938), Schedules of Reinforcement (1957), med C.B. Ferster) og andre. Av særskilt betydning var hans konsept om operant betinging. En operant er en klasse av strukturelt forskjellige men funksjonelt ekvivalente responser. For eksempel kan en rotte trykke ned en spak med venstre fot, høyre fot eller halen, alle disse responsene opererer på verden på samme måte og har samme konsekvenser.
Skinners empiriske arbeid utviklet seg fra tidlig forskning på rotters atferd i labyrinter til undersøkelse av «frie operanter» (fordi dyret nå hadde mulighet til å respondere i sitt eget tempo) i «operant kammer» (også kalt «Skinner boks»). Med denne metoden gjorde Skinner grundige eksperimentelle undersøkelser av effekten ulike «forsterkningsskjemaer» har på frekvens av operant atferd hos rotter og duer. Han hadde betydelig suksess i å trene dyr til å vise uventede responser, til ekstremt høye frekvenser av atferd og demonstrerte mange empiriske sammenhenger på atferdsnivå. Dette ga hans innfallsvinkel troverdighet.
Språk
Etterhvert som Skinner konsentrerte seg mer om de filosofiske grunnleggende prinsipper for atferdsvitenskap, vendte også hans oppmerksomhet seg mer mot språk. Hans bok Verbal Behavior (1957) definerte et vokabular og en teori for funksjonell analyse av verbal atferd.
Selv om den fikk en hard (men omstridt) kritikk av Noam Chomsky, har Skinners teorier om verbal atferd blitt anvendt med stor suksess på flere områder, inkludert behandling av barn med autisme. Som en lingvistisk teori har imidlertid Skinners idéer hatt svært begrenset innflytelse.
Det viktige for analyse av menneskets atferd var ikke så mye språktilegnelse, som interaksjonen mellom språk og observerbar atferd. I et essay publisert i boken Contingencies of Reinforcement (1969) klargjorde Skinner innfallsvinkelen at mennesker kan konstruere lingvistiske stimuli som videre kan oppnå kontroll over atferd på samme måte som eksterne stimuli kan. Muligheten for en slik «instrukskontroll» (regelstyring) av atferd betyr at forsterkningskontingenser ikke alltid vil lede til de samme effekter hos mennesker som de pålitelig gjør hos dyr. Fokuset hos atferdsanalytikere skiftet dermed til å forsøke å forstå interaksjonen mellom «instrukskontroll» og «kontingenskontroll», og også å forstå den atferdsprosessen som bestemmer hvilke regler som dannes og hvilken kontroll de oppnår over atferd. Viktige personer i dette arbeidet har vært A. Charles Catania, C. Fergus Lowe og Steven C. Hayes.
Behaviorisme i filosofien
Behaviorisme er både en psykologisk og filosofisk retning. De grunnleggende premisser for radikal behaviorisme er at studiet av atferd skal være en naturvitenskap, på samme måte som kjemi og fysikk, uten referanser til hypotetiske indre tilstander. Andre variasjoner, som teoretisk behaviorisme, tillater indre tilstander, men fordrer ikke at de er mentale eller er på noen måte en subjektiv opplevelse. Behaviorisme har et funksjonelt syn på atferd.
Det er visse syn innen analytisk filosofi som kaller seg, eller kalles, behavioristisk. I logisk behaviorisme forstås fysiologiske uttalelser som en bekreftelse på tilstander, som består av observerbar atferd. W. V. Quine anvendte en variasjon av behaviorisme, påvirket av noen av Skinners ideer, i sett eget arbeid om språk. Gilbert Ryle forsvarte en bestemt retning av filosofisk behaviorisme, beskrevet i hans bok The Concept of Mind. Ryles sentrale påstand var at dualisme representerer kategorifeil, og derfor egentlig er misforståelser i bruken av vanlig språk.
Det blir av og til hevdet at Ludwig Wittgenstein forsvarte en behavioristisk posisjon, og det er flere viktige overlapper mellom hans filosofi, logisk behaviorisme og radikalbehaviorisme. Men Wittgenstein var ikke en behaviorist, og hans verker er så rundt skrevet at de kan tolkes på flere måter. Matematikeren Alan Turing er også noen ganger ansett som en behaviorist, men selv gjorde han aldri den identifikasjonen.
Læring fra et behavioristisk perspektiv
Behaviorismen kan sees som en samlebetegnelse på ulike psykologiske retninger som går ut fra at atferd kan og skal studeres vitenskapelig. Her er ikke atferd begrenset til det organismer gjør som kan observeres, men også private prosesser som tenking og føling. Av historiske årsaker blir det gjort et skille mellom forklaringer på atferdsnivå og forklaringer på fysiologisk nivå. Når behaviorister snakker om at de ikke er opptatt av indre prosesser, er det fysiologiske prosesser de mener.
Behaviorister er i utgangspunktet enige om at det de er interessert i, er å kartlegge de funksjonelle sammenhengene mellom organisme og omgivelser. Skinner var opptatt av å finne lovmessigheter som gjelder for alle organismer, mens andre behaviorister som f.eks. A. Charles Catania også har vært opptatt av å studere arts-spesifikk atferd. En atferd sies å være lagt under kontroll når man vet hva som skal til for at den skal finne sted og endres.
Operant psykologi
Skinners muligens viktigste bidrag til psykologien er operant psykologi, som han påbegynte på midten av 1930-tallet, og som avløste
stimulus-respons-psykologien som bl.a. Pavlov sto for. Skinner innførte et skille mellom utløsende stimuli, hvor et stimulus umiddelbart følges av en atferd, og diskriminativ stimulus, hvor et stimulus gjør en atferd sannsynlig.
Operant psykologi gjør det mulig å beskrive mye mer avansert læring enn den enkle stimulus-respons-psykologien. Innen operant psykologi beskrives endring i atferd funksjonelt på fire måter:
En stimulus er noe som påvirker organismen på en eller annen måte. Det kan være et resultat av ei handling eller det kan være noe som er tilført av noen andre. Dette kalles tretermerskontingensen:
Forsterkningsskjema
På denne måten er det mulig å beskrive hva som skjer når læring finner sted. Læring skjer vanligvis ikke ved presentasjon (eller fjerning) av
første stimulus, stimulus må presenteres gjentatte ganger. Hvor mye og hvor ofte beskrives i forsterkningsskjema. De enkleste er konstant forsterkning, hvor stimulus presenteres (eller fjernes) hver gang atferden finner sted. Det er også vanlig å eksperimentere med å ha stimulus tilgjengelig bare av og til, slik at stimulus presenteres (eller fjernes) bare dersom atferden finner sted på bestemte tidspunkt. Ute i naturen hvor man ikke har kontroll over sånt, er forserkningsskjemaene vanligvis langt mer kompliserte.
Kompliserende faktorer
Ut fra dette er det lett å få inntrykk av at læring skjer ved straff eller belønning av den atferden som skal endres. Det er mer komplisert enn som så. Straff er f.eks. problematisk fordi straff har uheldige bivirkninger. Heller enn å straffe uønsket atferd, kan det være mer effektivt å forsterke atferd som er ønsket og som gjør den uønskede atferden umulig. Det er også slik at forsterkere endrer verdi. Det som forsterker en atferd i dag er ikke nødvendigvis det som forsterker atferden i morgen. Videre er den mest effektive forsterker ofte den som produseres av individet. Hvis man går inn for å belønne atferd hvor organismen produserer sine egne forsterkere (såkalt indre motivert atferd), risikerer man at organismen til slutt bare utfører atferden dersom den blir forsterket utenfra.
Undervisning
Det finnes ingen egen behavioristisk teori om undervisning. Behaviorisme er en teori som sier noe om hvordan atferd skal studeres, ikke hva man må forvente å finne. Behaviorister, blant annet B.F. Skinner, Ogden R. Lindsley og Siegfried E. Engelmann har imidlertid bygget opp modeller for hvordan effektiv undervisning bør foregå. De har vist at
læring er mest effektiv når
eleven deltar aktivt
tilbakemelding skjer umiddelbart
nytt stoff presenteres i en hastighet som er tilpasset eleven
Behavioristisk forskning forklarer altså hvorfor klasseromsundervisning med elever som følger samme tidsskjema, med prøver hvor resultatet
kommer dager eller uker etterpå, ikke fungerer særlig bra.
Metoder
De mest kjente undervisningsmetodene som er utviklet med utgangspunkt i behavioristisk perspektiv er direkteinstruksjon og presisjonsopplæring. Metodene går ut på å dele det som skal læres, ned i så små komponenter som mulig, og så presentere disse for elevene på forskjellige måter. Metodene innebærer at elevene er aktive deltagere i læringa, at de lærer i eget tempo, og at tilbakemelding er individuell og umiddelbar. Disse metodene vinner regelmessig konkurranser i USA om de mest effektive undervisningsmetodene. De er best egnet til å lære inn nytt materiale.
Kjente behaviorister
Ledende forløpere (*) og representanter for behaviorisme:
C. Lloyd Morgan *
Ivan Pavlov *
Edward Thorndike *
John B. Watson
Edward C. Tolman
Clark L. Hull
J.R. Kantor
B.F. Skinner
A. Charles Catania
Sigrid S. Glenn
C. Fergus Lowe
Howard Rachlin
J. E. R. Staddon
Richard Herrnstein
Se også
Atferdspsykologi
Referanser
Litteratur
Baum, W.M. (2005): Understanding behaviorism: Behavior, Culture and Evolution. Blackwell.
Ferster, C.B., & Skinner, B.F. (1957): Schedules of reinforcement. New York: Appleton-Century-Crofts.
Mills, John A. (2000): Control: A History of Behavioral Psychology, Paperback Edition, New York University Press
Lattal, K.A & Chase, P.N. (2003): Behavior Theory and Philosophy. Plenum
Rachlin, H. (1991) Introduction to modern behaviorism. (3. utg) New York: Freeman.
Skinner,B.F. (2002): Beyond Freedom & Dignity, Hackett Publishing Co, Inc
Skinner, B.F. (1938): The behavior of organisms. New York: Appleton-Century-Crofts.
Skinner, B.F. (1945): «The operational analysis of psychological terms» i: Psychological Review. s. 52, 270-277, 290-294.
Skinner, B.F. (1953): Science and Human Behavior, ISBN 0-02-929040-6
Skinner, B.F. (1957): Verbal behavior. Englewood Cliffs, NJ: Prentice-Hall.
Skinner, B.F. (1969): Contingencies of reinforcement: a theoretical analysis. New York: Appleton-Century-Crofts
Skinner, B.F. (1981): «Selection by consequences» i: Science, 213, s. 501-514.
Staddon, J. (2001): The new behaviorism: Mind, mechanism and society. Philadelphia, PA: Psychology Press. Pp. xiii, 1-211.
Watson, J.B. (1913): «Psychology as the behaviorist views it» i: Psychological Review, 20, s. 158-177. (online)
Watson, J.B. (1919): Psychology from the Standpoint of a Behaviorist
Zuriff, G.E. (1985): Behaviorism: A Conceptual Reconstruction , Columbia University Press
Eksterne lenker
Dictionary of the History of Ideas: Behaviorism
Books and Journal Articles On Behaviorism
www.bfskinner.org
www.behavior.org
Are theories of learning necessary?
Stanford Encyclopedia of Philosophy entry
Association for Behavior Analysis
Den norske atferdsanalytiske foreningen
behaviorMachine.com – Behavior Analysis for Everyone
Pedagogikk
Psykologi
Læring
Sinn
Psykologiens filosofi | norwegian_bokmål | 0.643654 |
organism_learn/adaptive_prediction.txt | ARTICLES
Adaptive prediction of environmental
changes by microorganisms
Amir Mitchell1
, Gal H. Romano2
, Bella Groisman1
, Avihu Yona1
, Erez Dekel3
, Martin Kupiec2
, Orna Dahan1
*
& Yitzhak Pilpel1,4*
Natural habitats of some microorganisms may fluctuate erratically, whereas others, which are more predictable, offer the
opportunity to prepare in advance for the next environmental change. In analogy to classical Pavlovian conditioning,
microorganisms may have evolved to anticipate environmental stimuli by adapting to their temporal order of appearance.
Here we present evidence for environmental change anticipation in two model microorganisms, Escherichia coli and
Saccharomyces cerevisiae. We show that anticipation is an adaptive trait, because pre-exposure to the stimulus that typically
appears early in the ecology improves the organism’s fitness when encountered with a second stimulus. Additionally, we
observe loss of the conditioned response in E. coli strains that were repeatedly exposed in a laboratory evolution experiment
only to the first stimulus. Focusing on the molecular level reveals that the natural temporal order of stimuli is embedded in the
wiring of the regulatory network—early stimuli pre-induce genes that would be needed for later ones, yet later stimuli only
induce genes needed to cope with them. Our work indicates that environmental anticipation is an adaptive trait that was
repeatedly selected for during evolution and thus may be ubiquitous in biology.
Microorganisms are constantly faced with environmental stimuli and
stresses. The cellular response to such challenges has been intensively
studied in several model organisms1–4. The simplest response strategy
to a stimulus is to monitor the environment and to respond directly
to it using designated mechanisms (Fig. 1). The environmental stress
response in yeast represents a more complicated strategy in which the
responses to many stresses are partially overlapping1,2. Theoretical
work has shown that when a population of microorganisms evolves
under erratic environmental fluctuations, cells may not effectively
monitor the environment, but rather use stochasticity to randomly
alternate between potential states5 (Fig. 1). Stochastic switching
might thus ensure that a portion of the population is prepared in
advance for the unpredicted challenge6,7. However, other, more predictable, environments offer organisms the opportunity to adopt an
alternative regulation strategy of anticipating an environmental
change based on a preceding signal. The capacity of some complex
multicellular eukaryotes to capture the statistics that govern the temporal connection between events in their environment, known as
classical Pavlovian conditioning, serves as a central paradigm in the
study of learning8
. Here we ask whether genetic regulatory networks
of microorganisms adaptively evolved to capture the temporal connections between subsequent stimuli in their environment. Most
recently, ‘anticipatory regulation’ was discovered9 (Fig. 1)—an association between environmental changes in bacteria. Specifically, this
study investigated the response of E. coli to temperature increase that
is followed by a drop in oxygen availability upon its entry to the
digestive tract. Interestingly, these two signals show a symmetrical
associative regulation pattern—each signal affects the expression of
genes needed to cope with both (Fig. 1). Remarkably, the authors
successfully decoupled the two responses during a laboratory evolution experiment in which the two signals were presented out-ofphase from one another. The ability to decouple the two responses
is an indication that the coupling seen in the wild type is not a trivial
combined response to the two stresses.
Here we show that biological systems that react to a unidirectional
temporal order of environmental changes may manifest a more elaborate predictive capacity. This capacity is reflected in a corresponding
asymmetric response strategy between subsequent stimuli, denoted S1
and S2 hereafter, and their designated responses R1 and R2, respectively. The first stimulus, S1, activates both responses, R1 and R2, yet
because the second stimulus, S2, does not predict the appearance of S1,
it only activates its own response (Fig. 1). We propose three criteria to
determine whether the observed cross-regulation pattern forms an
adaptive anticipatory response strategy that could be selected for by
evolution. First, asymmetric fitness advantage: pre-exposure to S1
increases the fitness under S2, yet pre-exposure to S2 should not
enhance fitness upon subsequent growth on S1. This ensures that
the natural order of stimuli was captured during evolution. Second,
1
Department of Molecular Genetics, Weizmann Institute of Science Rehovot 76100, Israel. 2
Department of Molecular Microbiology and Biotechnology, Tel Aviv University, Tel Aviv
69978, Israel. 3
Department of Molecular Cell Biology, Weizmann Institute of Science Rehovot 76100, Israel. 4
Department of Systems Biology, Harvard Medical School, Boston,
Massachusetts 02115, USA.
*These authors contributed equally to this work.
S1 S2
R1 R2
Direct
regulation
S1 S2
R1 R2
Stochastic
switching
R1 R2
S1 S2
R1 R2
Symmetrical
anticipatory
regulation
S1 S2
R1 R2
Asymmetrical
anticipatory
regulation
Figure 1 | Four possible regulation strategies in response to environmental
stimuli. Under direct regulation, each of the stimuli, S1 and S2, activates
exclusively the responses R1 and R2, respectively. Under stochastic
switching, cells randomly sample either R1 or R2 in response to either S1 or
S2. Under symmetrical anticipatory regulation, each of the stimuli activates
both responses. Under asymmetrical anticipatory regulation, the stimulus
that usually appears first in the ecology activates both responses, whereas the
stimulus that appears later induces only the second response.
Vol 460| 9 July 2009| doi:10.1038/nature08112
220
©2009 Macmillan Publishers Limited. All rights reserved
cost of preparation: pre-induction of genes needed to cope with S2 is
costly and not beneficial during S1. This indicates that early induction
is preserved due to a future benefit that is expected to exceed the cost,
upon encounter with S2. Third, specificity: the conditioned response is
specific to S1 and not to other unrelated stimuli, suggesting that anticipation evolved in response to the specific conditions of the ecological niche.
E. coli carbon source switch
During its life cycle E. coli alternates between two principal habitats,
intestines of mammals and water, sediment and soil10 (Supplementary Information). Focusing on the intestinal ecology reveals a predictable metabolic environment. Specifically, during passage along the
digestive tract, exposure to lactose precedes exposure to another sugar,
maltose11. We thus expect that this environment can select for asymmetric anticipation, so that bacteria that link the presence of lactose
with future exposure to maltose are expected to activate the maltose
genes already upon encounter with lactose. Such pre-induction is
expected to allow cells to better use maltose upon its encounter.
We start by examination of anticipatory behaviour at the molecular level. To test systematically the promoter activity of all relevant
operons in the presence of maltose and lactose we used an E. coli
promoter-fused green fluorescent protein (GFP) library previously
described12. Our experiments revealed the unidirectional regulation
pattern expected under a conditioned response strategy (Fig. 2a and
Supplementary Figs 1–4). Maltose operons, which are induced by
maltose, are also induced, but to a lower level, by lactose. We note
that the basic responsiveness of some of the maltose operons to
lactose is not restricted only to the E. coli strain used in our study13.
In contrast, and as expected by our hypothesis, the lactose operon
shows no response to maltose (Fig. 2a and Supplementary Figs 1–4).
The crucial question is whether the observed asymmetric response
strategy that implies anticipation is indeed adaptive—that is, whether
it could be selected for during evolution. Following the criteria outlined previously, we first validated that the conditioned response
indeed provides an asymmetric fitness advantage in an alternating
sugar environment. We monitored cell growth on maltose after an
initial growth phase on lactose. Reassuringly, we observed that the
wild-type strain displays a fitness advantage if growth on maltose was
preceded by growth on lactose (Fig. 3). We ensured that this advantage does not originate from the metabolic contribution of lactose as
a carbon source (Supplementary Information). In addition, and as
required by our first principle, we found that pre-exposure to maltose
before growth on lactose does not improve fitness (Fig. 3).
Our second criterion for adaptiveness requires that pre-induction
of the maltose genes is maladaptive or neutral during growth on
lactose. This criterion is crucial to rule out the possibility that the
maltose genes are induced during exposure to lactose simply because
they are needed during that phase. Built into the classical conditioning paradigm from the cognitive context is the possible extinction of
the association. To put in present case terms, it is expected that
repeated exposure to lactose without consequent arrival of maltose
would select for weakening of the conditioned response due to the
futile cost of preparation. Accordingly, we have examined laboratory-evolved strains of E. coli, which grew for 500 generations on
high levels of lactose yet without exposure to maltose14. We measured
the promoter activity of relevant operons in three lineages that
evolved independently under various lactose concentrations.
Notably, we found that, in all three lines, the maltose operons show
almost no activity in response to lactose (Fig. 2b and Supplementary
Fig. 5). Reassuringly, the strains seem to have preserved the ability to
activate the maltose genes in response to maltose itself (Supplementary Fig. 6), indicating that only the asymmetrical cross talk between
the two pathways was removed during this laboratory evolution
period. These results imply that the conditioning observed in the
wild-type strain is costly and that without a subsequent benefit that
should exceed this cost, purifying selection acts to eliminate this cross
talk. Consistent with the second criterion, the growth advantage LacZ MalE MalK MalP MalS MalZ
LacZ MalE MalK MalP MalS MalZ
0
0.25
0.50
0.75
1.00
Normalized promoter activity
Wild-type strain
Added sugar:
Lactose
Maltose
None
a
0
0.25
0.50
0.75
1.00
GFP-fused promoter
b Evolved strain
Figure 2 | Conditioned response in E. coli sugar metabolism. Promoter
activity in wild type (a) and the evolved strain (b). Colours mark the added
sugar. Error bars denote standard deviation of four repeats. Promoter
activities of four out of five maltose operons in wild type are significantly
higher under lactose relative to the untreated culture (t-test, P , 0.01
according to a Bonferroni adjustment). In contrast, none of the promoters
show increased activity in the evolved strain. The experiment was done in
M9-Glu medium and was repeated using glycerol as a background carbon
source (Supplementary Fig. 3) and further verified using quantitative
polymerase chain reaction with reverse transcription (RT–PCR)
(Supplementary Figs 2 and 4).
Evolved
0.98
0.99
1.00
1.01
1.02
1.03
1.04
Fitness advantage
Observed effect:
Directionality
Specificity
Extinction
Lac
Mal
Mal
Lac
Gal
Mal
Suc
Mal
Lac
Mal
Wild type
Figure 3 | Fitness in an alternating sugar environment. Two isogenic
populations were grown on M9-Gly either supplemented with a sugar as S1
(treated) or not (untreated). An equal amount of cells was diluted into media
containing the second sugar (S2) as a sole carbon source. The ratio treated/
untreated (after 2 h) represents the fitness advantage originating from preexposure to S1. The error bars denote standard deviation of three repeats. All
ratios are normalized to the ratio measured in a control experiment in which
S2 was glycerol (Methods). A significant fitness advantage was observed only
in the transfer of wild-type cells from lactose to maltose (P 5 0.02, t-test).
NATURE| Vol 460| 9 July 2009 ARTICLES
221
©2009 Macmillan Publishers Limited. All rights reserved
observed in the wild type due to exposure to lactose before maltose is
lost in the evolved strain that features extinction (Fig. 3).
Finally, as required by the specificity criterion, we ensured that
pre-exposure to other sugars does not improve growth of cells upon
transfer to maltose. As can be seen in Fig. 3, two alternative related
carbon sources, galactose and sucrose, cannot substitute lactose as a
preceding signal before maltose. This indicates that the observed
anticipation evolved in response to the specific stimuli pair that is
presented to the organism in its ecological niche. In summary, we
conclude that anticipation of subsequent carbon source changes is an
adaptive trait that has been selected by the natural ecology of E. coli.
The shift from fermentation to respiration in yeast
We next proceeded to a more complicated case that may also manifest environmental change anticipation. We examined how environmental anticipation is encoded in the regulatory network of
S. cerevisiae, and whether this response strategy has been selected
for because of a net fitness advantage it entails. We examined conditions that emulate some of the stresses that occur during the process
of alcoholic brew production, such as wine, by yeast15: Fig. 4a
describes this process, which starts at a highly osmotic and low pH
environment, followed by potentially lethal temperature raise due to
vigorous fermentation and accumulation of ethanol, culminating in
the diauxic shift—the exhaustion of fermentable sugars (for example,
glucose) and the switch to oxidative respiration16–19. Respiration is
challenging to the cell because it eventually generates oxygen radicals20. We checked whether yeast cells can cope better with these
stresses provided that they appear in their natural temporal order,
that is, whether yeasts use early stresses as predictive signals for the
likely arrival of later stresses. Such behaviour would indicate that
yeast cells are preparing for later challenges even before they arise.
To address these questions we systematically studied the survival
of S. cerevisiae under stresses that comprise the switch from its
preferred catabolic state, fermentation, to the alternative one, respiration (Fig. 4). As a potential manifestation of anticipation, we
focused on the cross-protection phenotype between different stress
pairs21,22. A cross-protection phenotype between two stresses exists if
pre-exposure to one stress improves the survival of cells under a
subsequent stress. Under our hypothesis we expect an asymmetrical
cross-protection phenotype between stress pairs. Particularly, we
predict that directionality of cross-protection will be in accordance
with the order of events during the transition from fermentation to
respiration. For example, because heat shock and ethanol accumulation precede oxidative stress in the ecology, we expect improved
survival under oxidative stress if it is preceded by either heat shock
or ethanol stress, yet we do not expect cross-protection if the stresses
are applied in the reverse order. Figure 4a shows the measured protection phenotype systematically tested for stresses that occur before
and after the diauxic shift. In accordance with our hypothesis, we
observe that the cross-protection phenotype is indeed extremely
asymmetric and, most importantly, that the directionality of protection fits the natural temporal context. Specifically, for each stress pair
protection is always stronger in the direction found in the natural
environment, thus fulfilling the asymmetric fitness advantage criterion. In a more faithful emulation of the natural habitat we have
also applied the three stresses, heat shock, ethanol and oxidative
stress, sequentially and observed an equally high cross-protection
activity (Supplementary Information). Note that activation of the
Nitrogen depletion
High osmolarity
Glucose depletion
46
1.5
3
29
0.001
Grape must Fermentation Respiration
4 5 19
Wine production process (time)
31
Diauxic
shift
Low pH
Heat Ethanol Oxidative stress
a
0
Fold cross-protection
Copper Low
pH
High
osmolarity
Heat Ethanol Acetic
acid
High
pH
50
40
30
20
10
b
Figure 4 | Cross-protection in the context of the diauxic shift. a, Stress
sequence in the process of wine production and measured cross-protection
phenotype. ‘Must’ is the medium in the beginning of the wine production
process. The values denote the fold protection gained by pre-exposure to a
mild stress followed by a severe stress. Red and blue arrows mark crossprotection when stress order is in accordance with the ecology or in reverse
order, respectively. Green arrows denote auto-protection. b, Specificity of
cross-protection against oxidative stress. The columns mark the observed
fold cross-protection provided by exposure to mild stress before severe
oxidative stress. Error bars donate standard deviations of three repeats.
Normalized survival ratio
b
0.70 0.75 0.80 0.85 0.90 0.95 1.00
0
5
10
15
Number of strains
Acquired cluster
Required dynamics
15 30 45 60 75 90
0
0.5
1.0
15 30 45 60 75 90
0
0
0
Induction
Time (min)
Stimuli setup:
YPD OX
HS OX
HS YPD
OS OX
OS YPD
S1 S2
S1 S2
S1 S2
a
Figure 5 | Candidate genes underlying the asymmetrical protection
between heat and oxidative stresses. a, Genome-wide expression was
measured in response to sequential stress pairs (untreated, YPD; osmotic
stress, OS; heat shock, HS; oxidative stress, OX). The top panel marks the
expression dynamics of an ideal gene that may facilitate cross-protection
against oxidative stress. The bottom panel marks the mean profile of 300
genes matching the desired pattern (Methods). b, A histogram of sensitivity
values of 29 deletion strains to heat (orange) and oxidative (purple) stresses.
The survival of each strain was normalized to the survival of the wild type to
test for increased sensitivity (individual strain sensitivity is shown in
Supplementary Fig. 7 and Supplementary Table 5).
ARTICLES NATURE| Vol 460| 9 July 2009
222
©2009 Macmillan Publishers Limited. All rights reserved
environmental stress response1,2, namely a set of genes that are transcribed in response to a wide spectrum of stresses, is less likely to
explain the observed cross-protection activity. Whereas the environmental stress response is more likely to result in a symmetrical
protection, we observe a very asymmetric effect. Furthermore, and as
required by the third criterion, we observe that protection against
oxidative stress is specific to stresses that precede respiration in the
natural environment, whereas stresses unrelated to the process do not
provide cross-protection (Fig. 4b).
We next investigated a potential molecular mechanism that might
account for the observed cross-protection capacity. We focused on
the pair of stresses that exhibits the strongest cross-protection phenotype, heat shock and oxidative stress, and measured genome-wide
gene expression in response to these stresses when they were introduced in isolation or one after the other. In particular, we applied a
heat shock as the first stress (S1), followed by an oxidative stress (S2).
As a control we also examined the response to oxidative stress that is
preceded by an osmotic stress, a condition we found not to crossprotect significantly against oxidative stress (Fig. 4b). We used these
series of events to define an ideal expression profile of genes that can
underlie the cross-protection phenotype and ultimately the anticipation capacity (Fig. 5a, see Methods for profile details). We also
defined a control profile, using the control osmotic stress (instead
of heat shock) as an early stimulus. Our search revealed a cluster of
300 genes with the desired profile (Fig. 5a). Consistent with asymmetric anticipation, this cluster shows a significant overlap with a set
of genes that are annotated in the literature (Proteome database) as
essential in oxidative stress but not in heat shock (P 5 0.013).
However, this cluster does not overlap significantly with a set of genes
that are annotated as essential in heat shock and not in oxidative
stress (P 5 0.2). Analysis of functional enrichment using Gene
Ontology annotations23 revealed a similar trend—a significant
enrichment of oxidative stress categories (Supplementary Table 3),
such as oxidoreductase activity, and many mitochondria-related categories, consistent with a known role of mitochondria for coping
with oxidative stress in yeasts24. However, no heat-shock-related categories were found to be enriched in this cluster. Reassuringly, the
genes that corresponded to the control profile (in which we still used
oxidative stress as an S2, yet with osmotic stress as an unprotective S1)
did not yield similar enrichment for oxidative-related activities
(Supplementary Table 4). This indicates that whereas an S1 stimulus
that provides cross-protection increases in advance the expression
level of genes relevant for the R2 response, a control S1 signal does
not affect these R2 genes.
We then tested whether induction of the conditioned gene set is
neutral in heat shock, as required by the second criterion. Towards
this aim we collected 29 strains, each of which is deleted for one of the
genes from the cluster described above, and tested their sensitivity to
heat shock and oxidative stress (Methods). Analysis of survival ratios
reveals that whereas 65% of the strains show increased sensitivity to
oxidative stress, none shows a significantly increased sensitivity to
heat shock relative to the wild-type strain (Fig. 5b and Supplementary
Fig. 7). This is a direct indication that the expression of many of the
heat-induced genes is at least neutral, if not maladaptive, under heat
shock. Taken together with the fact that these genes are essential
under oxidative stress, this experiment corroborates the claim that
an early preparation to oxidative stress during heat shock is adaptive
in this system.
Future outlook
An open question is how prevalent anticipatory regulation is in the
world of microorganisms. One way to address this issue is to develop
a mathematical framework that estimates the potential advantage of a
conditioned response in a given ecology. Intuitively, the added value
from anticipation depends both on environmental and on biological
parameters. Two cellular parameters, gain and cost, should be considered. A conditioned response is beneficial provided that benefit
gained from anticipation exceeds the cost of early preparation. These
parameters are in turn dependent on the typical time constants of the
environment, for example, the time gap between the appearances of
the two stimuli. Additionally, predictable environments in which
the stimuli are often sequentially coupled promote anticipation. A
simple equation captures the relationship between these variables
and their effect on the net fitness:
DF 5 p(B(Dt) 2 C(Dt)) 2 (1 2 p)(C(tS1)),
where DF is the difference in fitness between an anticipating cell and a
cell that adheres to direct regulation (Fig. 1), p is the probability that
S2 will occur given that S1 occurred, and B and C are functions
describing the benefit and cost of early preparation, respectively. Dt
is the length of the time interval between the appearance of S1 and S2,
and tS1 is the duration of the first stimulus. The dependence of fitness
on the interplay between the key factors is shown in Supplementary
Fig. 8. We note that quantitative predictions from the above phenomenological equation can be drawn by incorporating into the
model biologically meaningful and realistic parameters, such as measurable gain, cost and timescales (A.M. et al. in preparation).
To conclude, as we observed that anticipation at the cellular level
appears to be adaptive both in prokaryotes (E. coli) and eukaryotes
(S. cerevisiae), and under remote systems such as sugar metabolism
and stress response, we propose that it may be prevalent in a diverse
range of species. Asymmetric anticipation, along with associative
learning9
, memory25 and physiological adaptation26, represent a
powerful set of tools used by microorganisms to achieve a sophisticated environmental response.
METHODS SUMMARY
Strains. E. coli MG1655 was used for most experiments. An E. coli GFP reporter
library12 was used to monitor operon expression. The evolved E. coli strains were
described previously14
S. cerevisiae BY4741 (MATa; his3D1; leu2D0; met15D0; ura3D0) was used in all
yeast experiments. All deletion strains were obtained from the Saccharomyces
Genome Deletion Project27.
S. cerevisiae cross-protection. An overnight culture was diluted into fresh YPD
medium and grown to a concentration of 2 3 106 cells per ml. Cells were diluted
1:2 into the first stress (S1). Transfer into the second stress (S2) was done by
adding treated medium after centrifugation. Stresses were calibrated to achieve a
mild effect (,50% survival) for S1 and a severe effect (,0.5% survival) for S2
(Supplementary Table 1). Samples were taken from cultures at the end of each
treatment and plated. Each experiment was carried out in three repeats. The fold
protection was calculated as described in Supplementary Equation (1).
E. coli fitness advantage. Overnight cultures were diluted into M9-Gly plus S1
(for example, lactose; treated) or M9-Gly (untreated). After 3 h, population size
was determined and used to dilute (,1:100) an equal amount of cells into a new
growth medium containing low levels of S2 (for example, maltose) as a sole
carbon source. To account for a potential metabolic effect of residual S1, an
identical trace amount of S1 was added to the untreated growth medium. The
ratio treated/untreated after 2 h of growth was used as an indication of fitness
advantage originating from pre-exposure to S1. To rule out the possibility that
the growth advantage observed due to early exposure to lactose originates from
its metabolic value rather than its rule as a conditioning signal, we preformed a
control experiment (Supplementary Information).
Full Methods and any associated references are available in the online version of
the paper at www.nature.com/nature.
Received 25 March; accepted 7 May 2009.
Published online 17 June 2009.
1. Causton, H. C. et al. Remodeling of yeast genome expression in response to
environmental changes. Mol. Biol. Cell 12, 323–337 (2001).
2. Gasch, A. P. et al. Genomic expression programs in the response of yeast cells to
environmental changes. Mol. Biol. Cell 11, 4241–4257 (2000).
3. Cheung, K. J. et al. A microarray-based antibiotic screen identifies a regulatory
role for supercoiling in the osmotic stress response of Escherichia coli. Genome Res.
13, 206–215 (2003).
4. Tirosh, I., Weinberger, A., Carmi, M. & Barkai, N. A genetic signature of
interspecies variations in gene expression. Nature Genet. 38, 830–834 (2006).
NATURE| Vol 460| 9 July 2009 ARTICLES
223
©2009 Macmillan Publishers Limited. All rights reserved
5. Kussell, E. & Leibler, S. Phenotypic diversity, population growth, and information in
fluctuating environments. Science 309, 2075–2078 (2005).
6. Acar, M., Mettetal, J. T. & van Oudenaarden, A. Stochastic switching as a survival
strategy in fluctuating environments. Nature Genet. 40, 471–475 (2008).
7. Balaban, N. Q. et al. Bacterial persistence as a phenotypic switch. Science 305,
1622–1625 (2004).
8. Pavlov, I. P. Conditioned Reflexes (Oxford Univ. Press, 1927).
9. Tagkopoulos, I., Liu, Y. C. & Tavazoie, S. Predictive behavior within microbial
genetic networks. Science 320, 1313–1317 (2008).
10. Savageau, M. A. Escherichia coli habitats, cell-types, and molecular mechanisms of
gene control. Am. Nat. 122, 732–744 (1983).
11. Savageau, M. A. Demand theory of gene regulation. II. Quantitative application to
the lactose andmaltose operons of Escherichia coli. Genetics149,1677–1691 (1998).
12. Zaslaver, A. et al. A comprehensive library of fluorescent transcriptional reporters
for Escherichia coli. Nature Methods 3, 623–628 (2006).
13. Soupene, E. et al. Physiological studies of Escherichia coli strain MG1655: Growth
defects and apparent cross-regulation of gene expression. J. Bacteriol. 185,
5611–5626 (2003).
14. Oxman, E., Alon, U. & Dekel, E. Defined order of evolutionary adaptations:
experimental evidence. Evolution 62, 1547–1554 (2008).
15. Mortimer, R. K. Evolution and variation of the yeast (Saccharomyces) genome.
Genome Res. 10, 403–409 (2000).
16. Sablayrolles, J. M. & Barre, P. Kinetics of alcoholic fermentation under
anisothermal enological conditions. Am. J. Enol. Vitic. 44, 127–133 (1993).
17. Johnston, M. & Carlson, M. in The Molecular Biology of the Yeast Saccharomyces:
Gene Expression (eds Jones, E. W., Pringle, J. R. & Broach, J. R.) 193–282 (Cold
Spring Harbor Laboratory, 1992).
18. Bauer, F. F. & Pretorius, I. S. Yeast stress response and fermentation efficiency:
How to survive the making of wine - a review. SAJEV 21, 27–51 (2000).
19. Pretorius, I. S. Tailoring wine yeast for the new millennium: novel approaches to
the ancient art of winemaking. Yeast 16, 675–729 (2000).
20. Maris, A. F. et al.Diauxic shift-induced stress resistance against hydroperoxides in
Saccharomyces cerevisiae is not an adaptive stress response and does not depend
on functional mitochondria. Curr. Genet. 39, 137–149 (2001).
21. Sanchez, Y., Taulien, J., Borkovich, K. A. & Lindquist, S. Hsp104 is required for
tolerance to many forms of stress. EMBO J. 11, 2357–2364 (1992).
22. Berry, D. B. & Gasch, A. P. Stress-activated genomic expression changes serve a
preparative role for impending stress in yeast. Mol. Biol. Cell 19, 4580–4587
(2008).
23. Harris, M. A. et al. The Gene Ontology (GO) database and informatics resource.
Nucleic Acids Res. 32 (Database issue), D258–D261 (2004).
24. Grant, C. M., MacIver, F. H. & Dawes, I. W. Mitochondrial function is required for
resistance to oxidative stress in the yeast Saccharomyces cerevisiae. FEBS Lett. 410,
219–222 (1997).
25. Zacharioudakis, I., Gligoris, T. & Tzamarias, D. A yeast catabolic enzyme controls
transcriptional memory. Curr. Biol. 17, 2041–2046 (2007).
26. Braun, E. & Brenner, N. Transient responses and adaptation to steady state in a
eukaryotic gene regulation system. Phys. Biol. 1, 67–76 (2004).
27. Winzeler, E. A. et al. Functional characterization of the S. cerevisiae genome by
gene deletion and parallel analysis. Science 285, 901–906 (1999).
Supplementary Information is linked to the online version of the paper at
www.nature.com/nature.
Acknowledgements We thank S. Trattner–Frenkel and Z. Bloom for their help and
support in the yeast microarray experiments. We thank members of the Pilpel
laboratory for many discussions. We thank E. Schneidman, E. Ben-Jacob,
M. Springer, A. Tanay, U. Alon and D. Cavalieri for discussions and advice. We
thank U. Alon for providing the promoter–GFP fused plasmids. We thank the
Tauber Foundation, the Minerva Foundation, the Israel Science Foundation ‘Bikura
program’, the European Research Council ‘Ideas Program’ and the Ben May
Foundation for grant support. M.K. was supported from grants from the Israel
Science Foundation and the Israeli Ministry of Science and Technology.
Author Contributions A.M. raised the original idea and performed all the
experiments; G.R., B.G. and A.Y. participated in experiments; E.D. evolved the E. coli
strain; A.M., O.D. and Y.P. designed the experiments; A.M., M.K., O.D. and Y.P.
analysed the data; O.D. and Y.P. supervised the project; A.M., O.D. and Y.P.
interpreted the results and wrote the manuscript.
Author Information Reprints and permissions information is available at
www.nature.com/reprints. Correspondence and requests for materials should be
addressed to Y.P. ([email protected]).
ARTICLES NATURE| Vol 460| 9 July 2009
224
©2009 Macmillan Publishers Limited. All rights reserved
METHODS
S. cerevisiae media. All experiments were carried out in YPD medium (2% yeast
extract, 1% peptone, 1% dextrose) at 30 uC.
Sensitivity of deleted S. cerevisiae strains to heat and oxidative stress. To
examine the importance of the conditioned gene cluster under heat and oxidative stresses, 29 genes were chosen for additional experiments. This subset of
genes exhibited a two-phase induction profile: initial induction under heat shock
that further increased under oxidative stress. We then used strains in which each
of the 29 genes was deleted to check for increased stress sensitivity as follows.
Cultures were grown to stationary phase in a 96-well plate, diluted (1:20) into
fresh YPD medium and grown for additional 3 h. Cells were then diluted into
either mild heat shock (37 uC for 30 min) or mild oxidative stress (H2O2 1 mM
for 30 min). The stresses were calibrated to achieve 90% survival in the wild-type
strain. As a control, untreated cultures were diluted into YPD. All cultures were
then diluted (1:20) into fresh YPD and grown for 6 h. Population size was
monitored using a multi-well spectrophotometer at 595 nm. Survival ratio was
calculated by dividing the optical density of stress-treated cultures by the optical
density of untreated cultures. A t-test was used to determine whether the difference in the survival ratio of a deletion strain and the wild type is statistically
significant in a given stress.
Genome-wide expression experiments. An overnight culture was diluted into
fresh YPD and grown to concentration of 2.5 3 107 cells per ml. Cells were
diluted 3:4 into a fresh medium containing S1 (KCl 0.8 M, heat shock 40 uC or
YPD) and grown for 45 min. Cells were then diluted 1:10 into S2 (H2O2 0.66 mM
or YPD). Stress levels were calibrated to have relatively minor effects on survival.
Aliquots were removed 0, 30 and 45 min after the addition of S1 whereas in S2
aliquots were removed after 15, 30 and 45 min. RNA was extracted using
MasterPure, followed by hybridization to Affymetrix yeast 2.0 microarrays.
The expression data set was deposited in the GEO database (GSE15936).
Identifying candidate genes that facilitate conditioning. We defined an ideal
expression profile of a gene that can facilitate the observed cross-protection
phenotype (heat shock but not osmotic stress protects against oxidative stress).
The profile is defined accordingly: (1) induction in response to heat shock is 0.2
or higher in log2 scale; (2) induction in response to oxidative stress is 0.2 or
higher in log2 scale; (3) induction under osmotic stress is significantly lower than
in heat shock, 0.4 in log2 scale; (4) induction is maintained higher in the transfer
from heat shock to oxidative stress relative to transferring from heat shock to
YPD.
A control profile is similarly defined by using osmotic stress instead of heat
shock in the above requirements. The results are qualitatively similar under
alternative cut-off values (not shown).
E. coli media. All experiments were done in M9 medium (1 mM MgSO4, 0.1 mM
CaCl2, 0.05% casamino acids and 5 ng ml21 thiamine), supplemented with the
appropriate carbon source.
Three basic media were used: M9, M9-Gly (0.1% glycerol) and M9-Glu (0.1%
glucose plus 20 mM cAMP; cAMP was added to avoid glucose repression28).
To test the effect of various treatments the media were supplemented with the
following: 10 mM lactose, 5 mM maltose (these concentrations allow maximal
growth), 10 mM galactose, 10 mM sucrose (these concentrations are equal to the
concentration of lactose), 0.15 mM IPTG (this concentration achieves saturation
of the lactose operon induction29) and 25 mg ml21 kanamycin.
Monitoring operon transcription using the promtor-fused GFP library.
Overnight cultures, each carrying a unique plasmid with a specific promoter
fused to GFP, were diluted into fresh M9-Glu media, grown for 1 h at 37 uC and
then treated with sugars. Expression and cell growth (at 30 uC) were monitored
simultaneously using a multi-well reader (fluorescence at 495/520 nm, optical
density at 595 nm). The normalized GFP level and promoter activity were calculated similarly to in ref. 28. Briefly, the GFP signal was calculated after subtraction of the medium fluorescence and cell autofluorescence. GFP per cell was
calculated dividing the GFP by the optical density. Promoter activity ((dGFP/
dt)/optical density) was taken as the average promoter activity measured in a
time window of 1 h of exponential growth.
The following operons were examined in our research: MalEFG, MalK-lamBmalM, MalPQ, MalS, MalZ, LacZYA (referred to by the name of the first gene).
MalT was not included in our analysis because it shows no responsiveness to
maltose.
Monitoring operon transcription using the quantitative RT–PCR. Overnight
cultures were diluted into either M9-Gly or M9-Glu, alone or supplemented with
either lactose or maltose, and grown until the logarithmic phase was reached.
RNA was extracted using RNeasy Mini kit and used as a template for quantitative
RT–PCR (LightCycler 480 system).
28. Kaplan, S. et al. Diverse two-dimensional input functions control bacterial sugar
genes. Mol. Cell 29, 786–792 (2008).
29. Dekel, E. & Alon, U. Optimality and evolutionary tuning of the expression level of a
protein. Nature 436, 588–592 (2005).
doi:10.1038/nature08112
©2009 Macmillan Publishers Limited. All rights reserved | biology | 998 | https://da.wikipedia.org/wiki/Art | Art | Arten (species, forkortet sp., flertal: spp.) er den grundlæggende systematiske enhed inden for biologien. Arten defineres ofte som en naturlig gruppe af populationer, hvor udveksling af gener finder sted (eller kan finde sted) og som i forhold til forplantning er isoleret fra andre grupper. Det vil sige at kun individer inden for samme art kan parre sig og få forplantningsdygtigt afkom. Dette kaldes det biologiske artsbegreb. For organismer, der formerer sig ukønnet eller ved selvbestøvning, må arter afgrænses ud fra ligheder og forskelle mellem forskellige individer. Nogle dyrearter kan i fangenskab hybridisere og få fertilt afkom, men da dette ikke vil ske i naturen, selv om de mødes her, betragtes de som forskellige arter.
Eksempel
To heste kan parre sig og få et føl, der igen kan få føl med andre heste – hestene tilhører derfor samme art. En hest og et æsel kan også parre sig og deres unger kaldes enten muldyr eller mulæsel, afhængig af hvem der er moren, men muldyret eller mulæselet kan (normalt) ikke få unger, da de oftest er sterile. Af den grund regnes hest og æsel som to forskellige arter. Det samme princip gælder også for planterne. Denne naturskabte afgrænsning mellem to arter kaldes en artsbarriere. Den kan af og til gennembrydes, når ellers sterile krydsninger spontant eller kunstigt får gennemført en kromosomfordobling. Se f.eks. Vadegræs (Spartina pectinata).
Arter over for hybrider
Man kan dog godt komme ud for, at arter kan krydses og får blandet afkom, men hybriden vil kun kunne bestå på steder, hvor ingen af forældrearterne kan klare sig. Dette er et særligt udpræget problem med Rododendron (Rhododendron) og Tjørn (Crataegus), fordi disse slægter breder sig voldsomt efter skovbrand eller stormfald. Da hybriderne bliver frugtbare i en yngre alder end arterne, kan de dominere i en periode, men når skoven lukker sig, så fortrænges hybriderne og kun de specialiserede arter kan overleve i skovens dybe skygge eller ude i lyset i sumpe, på ur og i kalksten, m.m.
Flere artsbegreber
Fordi det biologiske artsbegreb kan være besværligt at anvende i praksis, er der efterhånden skabt en række andre artsbegreber:
Morfologisk artsbegreb Arterne adskiller sig fra hinanden ved deres bygning. Dette begreb er blevet meget anvendt gennem tiden.
Økologisk artsbegreb Definerer en art som en gruppe af organismer, der udfylder samme niche. Krydsninger mellem to nærtstående arter vil ikke være optimalt tilpasset til forældrearternes nicher og vil ikke klare sig i konkurrencen.
Evolutionære artsbegreb Også kaldet det kladistiske eller fylogenetiske artsbegreb. Naturen er dynamisk, ikke statisk - alle arter ændrer sig med tiden og bliver, hvis de ikke uddør som følge af konkurrence, naturkatastrofer m.v., til én eller flere nye arter. Det evolutionære artsbegreb minder om det biologiske, men inddrager tidsdimensionen, det vil sige at en art udvikler sig over tid og at nye arter opstår ved artsdannelse. Individer der fylogenetisk har samme stamfader tilhører samme art.
Pluralistisk artsbegreb En art er et samfund af populationer, der formerer sig og lever inden for en bestemt niche i naturen.
Se også
Systematik
Evolutionsteori
Kilder
Lars Skipper: Hvad er en art? Citat: "...Arten er den eneste [klassifikations-kategori] der eksisterer i virkeligheden, alle andre (slægter, familier, ordener m.v.) er indført for overskuelighedens skyld..."
Eksterne henvisninger
2003-12-31, ScienceDaily: Working On The 'Porsche Of Its Time': New Model For Species Determination Offered Citat: "...two species of dinosaur that are members of the same genera varied from each other by just 2.2 percent. Translation of the percentage into an actual number results in an average of just three skeletal differences out of the total 338 bones in the body. Amazingly, 58 percent of these differences occurred in the skull alone. "This is a lot less variation than I'd expected," said Novak..."
2003-08-08, ScienceDaily: Cross-species Mating May Be Evolutionarily Important And Lead To Rapid Change, Say Indiana University Researchers Citat: "...the sudden mixing of closely related species may occasionally provide the energy to impel rapid evolutionary change..."
2004-01-09 ScienceDaily: Mayo Researchers Observe Genetic Fusion Of Human, Animal Cells; May Help Explain Origin Of AIDS Citat: "...The researchers have discovered conditions in which pig cells and human cells can fuse together in the body to yield hybrid cells that contain genetic material from both species..."What we found was completely unexpected," says Jeffrey Platt, M.D..."
2000-09-18, ScienceDaily: Scientists Unravel Ancient Evolutionary History Of Photosynthesis Citat: "...gene-swapping was common among ancient bacteria early in evolution..."
2004-06-07, Sciencedaily: Parting Genomes: University Of Arizona Biologists Discover Seeds Of Speciation Citat: "...There's a huge amount of biodiversity out there, and we don't know where it comes from. Evolutionary biologists are excited to figure out what causes what we see out there--the relative forces of selection and drift--whether things are adapting to their environment or variation is random..."
2005-07-05, Sciencedaily: Trees, Vines And Nets -- Microbial Evolution Changes Its Face Citat: "... EBI researchers have changed our view of 4 billion years of microbial evolution...In all, more than 600,000 vertical transfers are observed, coupled with 90,000 gene loss events and approximately 40,000 horizontal gene transfers...A few species, including beneficial nitrogen-fixing soil bacteria, appear to be 'champions'of horizontal gene transfer; "it's entirely possible that apparently harmless organisms are quietly spreading antibiotic resistance under our feet," concludes Christos Ouzounis..."
2005-11-11, Sciencedaily: Lateral Thinking Produces First Map Of Gene Transmission Citat: "...Their results clearly show genetic modification of organisms by lateral transfer is a widespread natural phenomenon, and it can occur even between distantly related organisms... it was assumed that transfer of genes could only be vertical, i.e. from parents to offspring..."
Økologi
Biologi | danish | 0.791178 |
ring_finger_not_move/ulnarnerveentrapment.txt | 
[ from the American Academy of Orthopaedic Surgeons ](https://www.aaos.org/)
[  ](/)
[ Diseases & Conditions ](/en/diseases--conditions/)
Popular Topics
[ Arthritis ](/en/diseases--conditions/?topic=Arthritis) [ Broken Bones
](/en/diseases--conditions/?topic=BrokenBones) [ Osteoporosis ](/en/diseases--
conditions/?topic=Osteoporosis) [ Sports Injuries ](/en/diseases--
conditions/?topic=SportsInjuries) [ Tumors ](/en/diseases--
conditions/?topic=Tumors) [ Children's Conditions ](/en/diseases--
conditions/?topic=ChildrensConditions) [ Ortho-pinion Blog ](/en/diseases--
conditions/?topic=Orthopinion)
[ View All Topics ](/en/diseases--conditions/)
By Body Part
[ Neck ](/en/diseases--conditions/?bodyPart=Neck) [ Back ](/en/diseases--
conditions/?bodyPart=Back) [ Shoulder ](/en/diseases--
conditions/?bodyPart=Shoulder) [ Elbow ](/en/diseases--
conditions/?bodyPart=Elbow) [ Hand & Wrist ](/en/diseases--
conditions/?bodyPart=HandWrist) [ Hip & Thigh ](/en/diseases--
conditions/?bodyPart=HipThigh) [ Knee & Lower Leg ](/en/diseases--
conditions/?bodyPart=KneeLowerLeg) [ Foot & Ankle ](/en/diseases--
conditions/?bodyPart=FootAnkle)
Featured
[ 
Patellofemoral Pain Syndrome
](/en/diseases--conditions/patellofemoral-pain-syndrome/) [ 
Clavicle Fracture (Broken Collarbone)
](/en/diseases--conditions/clavicle-fracture-broken-collarbone/)
[ Treatment ](/en/treatment/)
Popular Topics
[ Arthroscopy ](/en/treatment/?topic=Arthroscopy) [ Joint Replacement
](/en/treatment/?topic=JointReplacement) [ Preparing for Surgery
](/en/treatment/?topic=PreparingForSurgery) [ Nonsurgical Treatments
](/en/treatment/?topic=NonsurgicalTreatments) [ Diagnostic Tests
](/en/treatment/?topic=DiagnosticTests) [ Ortho-pinion Blog
](/en/treatment/?topic=Orthopinion)
[ View All Topics ](/en/treatment/)
By Body Part
[ Neck ](/en/treatment/?bodyPart=Neck) [ Back ](/en/treatment/?bodyPart=Back)
[ Shoulder ](/en/treatment/?bodyPart=Shoulder) [ Elbow
](/en/treatment/?bodyPart=Elbow) [ Hand & Wrist
](/en/treatment/?bodyPart=HandWrist) [ Hip & Thigh
](/en/treatment/?bodyPart=HipThigh) [ Knee & Lower Leg
](/en/treatment/?bodyPart=KneeLowerLeg) [ Foot & Ankle
](/en/treatment/?bodyPart=FootAnkle)
Featured
[ 
Knee Arthroscopy
](/en/treatment/knee-arthroscopy/) [ 
Total Hip Replacement
](/en/treatment/total-hip-replacement/)
[ Recovery ](/en/recovery/)
Popular Topics
[ Recovery from Surgery ](/en/recovery/?topic=RecoveryFromSurgery) [
Rehabilitation Exercise Handouts ](/en/recovery/?topic=RehabilitationExercise)
[ Pain Management ](/en/recovery/?topic=PainManagement) [ Ortho-pinion Blog
](/en/recovery/?topic=Orthopinion)
[ View All Topics ](/en/recovery/)
By Body Part
[ Neck ](/en/recovery/?bodyPart=Neck) [ Back ](/en/recovery/?bodyPart=Back) [
Shoulder ](/en/recovery/?bodyPart=Shoulder) [ Elbow
](/en/recovery/?bodyPart=Elbow) [ Hand & Wrist
](/en/recovery/?bodyPart=HandWrist) [ Hip & Thigh
](/en/recovery/?bodyPart=HipThigh) [ Knee & Lower Leg
](/en/recovery/?bodyPart=KneeLowerLeg) [ Foot & Ankle
](/en/recovery/?bodyPart=FootAnkle)
Featured
[ 
Activities After Total Knee Replacement
](/en/recovery/activities-after-knee-replacement/) [ 
Rotator Cuff and Shoulder Conditioning Program
](/en/recovery/rotator-cuff-and-shoulder-conditioning-program/)
[ Staying Healthy ](/en/staying-healthy/)
Popular Topics
[ Bone Health ](/en/staying-healthy/?topic=BoneHealth) [ Fitness & Exercise
](/en/staying-healthy/?topic=FitnessExercise) [ Sports Injury Prevention
](/en/staying-healthy/?topic=SportsInjuryPrevention) [ Home & Recreational
Safety ](/en/staying-healthy/?topic=HomeRecreationalSafety) [ Ortho-pinion
Blog ](/en/staying-healthy/?topic=Orthopinion) [ Diet & Nutrition
](/en/staying-healthy/?topic=DietNutrition)
[ View All Topics ](/en/staying-healthy/)
By Body Part
[ Neck ](/en/staying-healthy/?bodyPart=Neck) [ Back ](/en/staying-
healthy/?bodyPart=Back) [ Shoulder ](/en/staying-healthy/?bodyPart=Shoulder) [
Elbow ](/en/staying-healthy/?bodyPart=Elbow) [ Hand & Wrist ](/en/staying-
healthy/?bodyPart=HandWrist) [ Hip & Thigh ](/en/staying-
healthy/?bodyPart=HipThigh) [ Knee & Lower Leg ](/en/staying-
healthy/?bodyPart=KneeLowerLeg) [ Foot & Ankle ](/en/staying-
healthy/?bodyPart=FootAnkle)
Featured
[ 
A Guide to Safety for Young Athletes
](/en/staying-healthy/a-guide-to-safety-for-young-athletes/) [ 
Bone Health Basics
](/en/staying-healthy/bone-health-basics/)
# Our knowledge of orthopaedics. Your best health.
 
[   ](/)
 
[ from the American Academy of Orthopaedic Surgeons ](https://www.aaos.org/)
Diseases & Conditions
[ View All Topics ](/en/diseases--conditions/)
[ By Body Part ](/en/diseases--conditions/?bodyPart=Neck)
Featured
Popular Topics
[ Arthritis ](/en/diseases--conditions/?topic=Arthritis) [ Broken Bones
](/en/diseases--conditions/?topic=BrokenBones) [ Osteoporosis ](/en/diseases--
conditions/?topic=Osteoporosis) [ Sports Injuries ](/en/diseases--
conditions/?topic=SportsInjuries) [ Tumors ](/en/diseases--
conditions/?topic=Tumors) [ Children's Conditions ](/en/diseases--
conditions/?topic=ChildrensConditions) [ Ortho-pinion Blog ](/en/diseases--
conditions/?topic=Orthopinion)
Treatment
[ View All Topics ](/en/treatment/)
[ By Body Part ](/en/treatment/?bodyPart=Neck)
Featured
Popular Topics
[ Arthroscopy ](/en/treatment/?topic=Arthroscopy) [ Joint Replacement
](/en/treatment/?topic=JointReplacement) [ Preparing for Surgery
](/en/treatment/?topic=PreparingForSurgery) [ Nonsurgical Treatments
](/en/treatment/?topic=NonsurgicalTreatments) [ Diagnostic Tests
](/en/treatment/?topic=DiagnosticTests) [ Ortho-pinion Blog
](/en/treatment/?topic=Orthopinion)
Recovery
[ View All Topics ](/en/recovery/)
[ By Body Part ](/en/recovery/?bodyPart=Neck)
Featured
Popular Topics
[ Recovery from Surgery ](/en/recovery/?topic=RecoveryFromSurgery) [
Rehabilitation Exercise Handouts ](/en/recovery/?topic=RehabilitationExercise)
[ Pain Management ](/en/recovery/?topic=PainManagement) [ Ortho-pinion Blog
](/en/recovery/?topic=Orthopinion)
Staying Healthy
[ View All Topics ](/en/staying-healthy/)
[ By Body Part ](/en/staying-healthy/?bodyPart=Neck)
Featured
Popular Topics
[ Bone Health ](/en/staying-healthy/?topic=BoneHealth) [ Fitness & Exercise
](/en/staying-healthy/?topic=FitnessExercise) [ Sports Injury Prevention
](/en/staying-healthy/?topic=SportsInjuryPrevention) [ Home & Recreational
Safety ](/en/staying-healthy/?topic=HomeRecreationalSafety) [ Ortho-pinion
Blog ](/en/staying-healthy/?topic=Orthopinion) [ Diet & Nutrition
](/en/staying-healthy/?topic=DietNutrition)
Print
Email
Facebook
Twitter
English
[ español ](/es/diseases--conditions/atrapamiento-del-nervio-cubital-en-el-
codo-sindrome-del-tunel-cubital-ulnar-nerve-entrapment-at-the-elbow/)
###### Diseases & Conditions
Ulnar Nerve Entrapment at the Elbow (Cubital Tunnel Syndrome)
Ulnar nerve entrapment occurs when the ulnar nerve in the arm becomes
compressed (squeezed or restricted) or irritated.
The ulnar nerve is one of the three main nerves in your arm. It travels from
your neck down into your hand and can be constricted in several places along
the way, such as beneath the collarbone or at the wrist. The most common place
for compression of the nerve is behind the inside part of the elbow. Ulnar
nerve compression at the elbow is called cubital tunnel syndrome.
Numbness and tingling in the pinky and ring fingers are common symptoms of
cubital tunnel syndrome.
* In most cases, symptoms can be managed with nonsurgical treatments like changes in activities and bracing.
* If nonsurgical methods do not improve your symptoms, or if the nerve compression is causing muscle weakness or damage in your hand, your doctor may recommend surgery to take pressure off the nerve and allow it to move more freely.
This illustration of the bones in the shoulder, arm, and hand shows the path
of the ulnar nerve.
_**Reproduced from Mundanthanam GJ, Anderson RB, Day C: Ulnar nerve palsy.
Orthopaedic Knowledge Online 2009. Accessed August 2011.** _
## Anatomy
At the elbow, the ulnar nerve travels through a tunnel of tissue (the cubital
tunnel) that runs under a bump of bone at the inside of your elbow. This bony
bump is called the medial epicondyle. The spot where the nerve runs under the
medial epicondyle is commonly referred to as the "funny bone." At the funny
bone, the nerve is close to your skin, and bumping it causes a shock-like
feeling.
The ulnar nerve runs behind the medial epicondyle on the inside of the elbow.
Beyond the elbow, the ulnar nerve travels under muscles on the inside of your
forearm and into your hand on the side of the palm with the pinky finger. As
the nerve enters the hand, it travels through another tunnel (Guyon's canal).
The ulnar nerve gives feeling to the little finger and half of the ring
finger. It also controls most of the little muscles in the hand that help with
fine movements, and some of the bigger muscles in the forearm that help you
make a strong grip.
The ulnar nerve gives sensation (feeling) to the little finger and to half of
the ring finger on both the palm and back side of the hand.
Related Articles
[
###### Diseases & Conditions
Carpal Tunnel Syndrome
](/en/diseases--conditions/carpal-tunnel-syndrome/) [
###### Treatment
Electrodiagnostic Testing
](/en/treatment/electrodiagnostic-testing/) [
###### Diseases & Conditions
Elbow Dislocation
](/en/diseases--conditions/elbow-dislocation/)
## Cause
In many cases of cubital tunnel syndrome, the exact cause is not known.
The ulnar nerve is especially vulnerable to compression at the elbow because
it must travel through a narrow space with very little soft tissue to protect
it. Also, when you bend your elbow, you slightly compress and stretch the
nerve and decrease its blood supply. This is often why the symptoms of cubital
tunnel syndrome get worse when the elbow is bent.
### _Common Causes of Compression_
There are several things that can cause pressure on the nerve at the elbow:
* When you bend your elbow, the ulnar nerve must stretch around the bony ridge of the medial epicondyle. Because this stretching can irritate the nerve and decrease its blood supply, keeping your elbow bent for long periods or repeatedly bending your elbow can cause painful symptoms. For example, many people sleep with their elbows bent, which can aggravate symptoms of ulnar nerve compression and cause you to wake up at night or in the morning with your fingers asleep.
* In some people, the nerve slides out from behind the medial epicondyle when the elbow is bent. Over time, this sliding back and forth may irritate the nerve.
* Leaning on your elbow for long periods of time can put pressure on the nerve.
* Fluid buildup in the elbow can cause swelling that may compress the nerve.
* A direct blow to the inside of the elbow can cause pain, electric shock sensation, and numbness in the little and ring fingers. This is commonly called "hitting your funny bone."
* Throwing a baseball puts a large amount of stress on the inside of the elbow and can sometimes lead to ulnar nerve irritation.
### _Risk Factors_
Some factors put you more at risk for developing cubital tunnel syndrome.
These include:
* Prior [ fracture ](/en/diseases--conditions/elbow-olecranon-fractures/ "Elbow \(Olecranon\) Fractures") or [ dislocation ](/en/diseases--conditions/elbow-dislocation/ "Elbow Dislocation") of the elbow
* [ Bone spurs/arthritis of the elbow ](/en/diseases--conditions/osteoarthritis-of-the-elbow/ "Arthritis of the Elbow")
* Swelling of the elbow joint
* Cysts near the elbow joint
* Repetitive or prolonged activities that require the elbow to be bent or flexed
* Baseball pitching
To Top
## Symptoms
Cubital tunnel syndrome can cause an aching pain on the inside of the elbow.
Most of the symptoms, however, occur in your hand.
* Numbness and tingling in the ring finger and little finger are common symptoms of ulnar nerve entrapment. Often, these symptoms come and go. They happen more often when the elbow is bent, such as when driving or holding the phone. Some people wake up at night because their fingers are numb.
* The feeling of "falling asleep" in the ring finger and little finger, especially when your elbow is bent. In some cases, it may be harder to move your fingers in and out, or to manipulate objects.
* Weakening of the grip and difficulty with finger coordination (such as typing or playing an instrument) may occur. These symptoms are usually seen in more severe cases of nerve compression.
* If the nerve is very compressed or has been compressed for a long time, muscle wasting in the hand can occur. Once this happens, muscle wasting cannot be reversed. For this reason, it is important to see your doctor:
* If symptoms are severe, or
* If symptoms are less severe but have been present for more than 6 weeks
**(Left)** Photo shows the appearance of normal muscle between the thumb and
index finger when the fingers are pinched. **(Right)** In this photo, muscle
wasting has occurred due to long-term ulnar nerve entrapment.
## Home Remedies
There are many things you can do at home to help relieve symptoms. If your
symptoms interfere with normal activities or last more than a few weeks, be
sure to schedule an appointment with your doctor.
* Avoid activities that require you to keep your arm bent for long periods of time.
* If you use a computer frequently, make sure that your chair is not too low. Do not rest your elbow on the armrest.
* Avoid leaning on your elbow or putting pressure on the inside of your arm. For example, do not drive with your arm resting on the open window.
* Keep your elbow straight at night when you are sleeping. This can be done by wrapping a towel around your straight elbow or wearing an elbow pad backwards.
Loosely wrapping a towel around your arm with tape can help you remember not
to bend your elbow during the night.
## Doctor Examination
### _Medical History and Physical Examination_
Your doctor will discuss your medical history and general health. They may
also ask about your work, your activities, and what medications you are
taking.
After discussing your symptoms and medical history, your doctor will examine
your elbow and hand to determine which nerve is compressed and where it is
compressed. The doctor may also do a neck exam, as pinched nerves in the neck
can cause similar symptoms.
Some of the physical examination tests your doctor may do include:
* Tap over the nerve at the funny bone. If the nerve is irritated, tapping can cause a shock into the little finger and ring finger (Tinel's sign) — although this can happen when the nerve is normal as well.
* Check whether the ulnar nerve slides out of normal position when you bend your elbow.
* Move your neck, shoulder, elbow, and wrist to see if different positions cause symptoms.
* Check for feeling and strength in your hand and fingers.
To perform Tinel's test for nerve damage, your doctor will lightly tap along
the inside of the elbow joint, directly over the ulnar nerve.
### _Tests_
**X-rays.** X-rays provide detailed pictures of bone. Most causes of
compression of the ulnar nerve cannot be seen on an X-ray. However, your
doctor may take X-rays of your elbow or wrist to look for bone spurs,
arthritis, or other places that the bone may be compressing the nerve.
**Nerve conduction studies.** These tests can determine how well the nerve is
working and help identify where it is being compressed. The test sends an
electric current down the arm and looks to see if the current gets slowed
along its path. If the current gets slowed down, this is likely an area of
nerve compression. This can also help the doctor determine whether the pinched
nerve is at the elbow, wrist, or neck.
Nerves are like electrical cables that travel through your body carrying
messages between your brain and muscles. When a nerve is not working well, it
takes longer for it to conduct.
Nerve conduction studies can also determine whether the compression is causing
muscle damage. During the test, small needles are put into some of the muscles
that the ulnar nerve controls. Muscle damage (especially with wasting) is a
sign of more severe nerve compression.
Nerve conduction studies measure the signals travelling in the nerves of your
arm and hand.
To Top
## Treatment
Unless your nerve compression has caused disability or any muscle wasting,
your doctor will most likely recommend trying nonsurgical treatment first.
### _Nonsurgical Treatment_
**Nonsteroidal anti-inflammatory drugs (NSAIDs).** If your symptoms have just
started, your doctor may recommend an anti-inflammatory medicine, such as
ibuprofen or naproxen, to help reduce swelling around the nerve.
Although steroids, such as cortisone, are very effective anti-inflammatory
medicines, steroid injections are generally not used to treat cubital tunnel
syndrome because there is a risk of damage to the nerve. However, sometimes
your doctor will prescribe a short course of oral steroids (taken by mouth) to
help relieve the inflammation around the nerve.
**Bracing or splinting.** Your doctor may prescribe a padded brace or splint
to wear at night to keep your elbow in a straight position.
**Nerve gliding exercises.** Some doctors think that exercises to help the
ulnar nerve slide through the cubital tunnel at the elbow and the Guyon's
canal at the wrist can improve symptoms. These exercises may also help prevent
stiffness in the arm and wrist.
Examples of nerve gliding exercises. With your arm in front of you and the
elbow straight, curl your wrist and fingers toward your body, then extend them
away from you, and then bend your elbow.
### _Surgical Treatment_
Your doctor may recommend surgery to take pressure off of the nerve if:
* Nonsurgical methods have not improved your condition
* The ulnar nerve is very compressed
* Nerve compression has caused muscle weakness or damage
There are a few surgical procedures that will relieve pressure on the ulnar
nerve at the elbow. Your orthopaedic surgeon will talk with you about the
option that would be best for you.
These procedures are generally done on an outpatient basis (where you go home
the same day as your surgery).
**Cubital tunnel release.** In this operation, the ligament roof of the
cubital tunnel is cut and divided. This increases the size of the tunnel and
decreases pressure on the nerve.
This illustration shows the path of the ulnar nerve through the cubital
tunnel. Structures that may compress the nerve — such as the medial epicondyle
and ulnar collateral ligament — are also shown.
_** Reproduced from J Bernstein, ed: Musculoskeletal Medicine. Rosemont, IL,
American Academy of Orthopaedic Surgeons, 2003. ** _
After the procedure, the ligament begins to heal, and new tissue grows across
the division. The new growth heals the ligament and allows more space for the
ulnar nerve to slide through.
Cubital tunnel release tends to work best when the nerve compression is mild
or moderate and the nerve does not slide out from behind the bony ridge of the
medial epicondyle when the elbow is bent.
In this surgical photo, a cubital tunnel release has been performed to
decompress, or relieve pressure on, the ulnar nerve. The arrow shows the
portion of the nerve that has become narrowed over time due to compression.
**Ulnar nerve anterior transposition.** In most cases, the nerve is moved from
its place behind the medial epicondyle to a new place in front of it. Moving
the nerve to the front of the medial epicondyle keeps it from getting caught
on the bony ridge and stretching when you bend your elbow. It allows a more
direct path for the nerve and removes the compression on the nerve when you
bend your elbow. This procedure is called an anterior transposition of the
ulnar nerve.
The nerve can be moved to lie:
* Under the skin and fat but on top of the muscle (subcutaneous transposition)
* Within the muscle (intermuscular transposition)
* Under the muscle (submuscular transposition)
For anterior transposition of the ulnar nerve, an incision is made along the
inside of the elbow (pictured) or along the back side of the elbow.
### _Surgical Recovery_
* Depending on the type of surgery you have, you may need to wear a splint for a few days to weeks after the operation. A submuscular transposition usually requires a longer time (3 to 6 weeks) in a splint.
* Most patients are allowed to move their elbow right away to prevent any scarring of the nerve.
* While motion often starts immediately, you will avoid any heavy lifting with the arm for a few weeks.
* Your surgeon may recommend physical therapy exercises to help you regain strength and motion in your arm. They will also talk with you about when it will be safe to return to all your normal activities.
### _Surgical Outcome_
The results of surgery are generally good. Each method of surgery has a
similar success rate for routine cases of nerve compression.
If the nerve is very badly compressed or if there is muscle wasting, the nerve
may not be able to return to normal, and some symptoms may remain even after
the surgery. Nerves recover slowly, and it may take a long time to know how
well the nerve will do after surgery.
To Top
Reviewed by members of
[ ASES (American Shoulder and Elbow Surgeons) ](https://www.ases-assn.org/)
Last Reviewed
April 2024
Contributed and/or Updated by
[ Brandon Erickson, MD, FAAOS
](https://disclosure.aaos.org/getsummary/000001186232/04-27-2023) [ William R.
Aibinder, MD ](https://disclosure.aaos.org/getsummary/000000699998/10-21-2023)
[ George S. Athwal, MD
](https://disclosure.aaos.org/getsummary/000000210281/06-02-2020) [ Jay D.
Keener, MD, FAAOS
](https://disclosure.aaos.org/getsummary/000000155030/06-04-2010)
Peer-Reviewed by
[ Thomas Ward Throckmorton, MD, FAAOS
](https://disclosure.aaos.org/getsummary/000000212026/09-23-2023) [ Stuart J.
Fischer, MD, FAAOS
](https://disclosure.aaos.org/getsummary/000000017539/07-26-2020) [ J. Michael
Wiater, MD, FAAOS
](https://disclosure.aaos.org/getsummary/000000135708/03-06-2011)
AAOS does not endorse any treatments, procedures, products, or physicians
referenced herein. This information is provided as an educational service and
is not intended to serve as medical advice. Anyone seeking specific
orthopaedic advice or assistance should consult his or her orthopaedic
surgeon, or locate one in your area through the AAOS [ Find an Orthopaedist
](http://www7.aaos.org/member/directory/search.aspx?directory=public) program
on this website.
[ About OrthoInfo ](/en/about-orthoinfo/) [ Editorial Board ](/en/editorial-
board/) [ Our Contributors ](/en/about-orthoinfo/contributors/) [ Our
Subspecialty Partners ](/en/about-orthoinfo/specialty-partners/) [ Contact Us
](/en/about-orthoinfo/contact-us/)
[ Terms & Privacy Policy ](/en/about-orthoinfo/terms-and-conditions/ "Terms &
Conditions and Privacy Policy") [ Linking (Free Use) Policy ](/en/about-
orthoinfo/linking-policy/ "Linking \(Free Use\) Policy") [ Content Licensing
](https://www.aaos.org/about/corporate-engagement/corporate-engagement-
opportunities/orthoinfo-licensing-opportunities/ "OrthoInfo Licensing
Opportunities") [ Advertising ](https://mwomedia.com/orthoinfo/) **[ Find an
FAAOS Surgeon
](https://www7.aaos.org/member/directory/search.aspx?directory=public) **
[  ](/en/)
[  ](https://www.aaos.org/)
Copyright ©1995-2023 by the American Academy of Orthopaedic Surgeons. All
material on this website is protected by copyright. All rights reserved. This
website also contains material copyrighted by third parties.
X
[ https://embed.questionpro.com ](https://embed.questionpro.com)
| biology | 603068 | https://sv.wikipedia.org/wiki/Muskelatrofi | Muskelatrofi | Muskelatrofi innebär att musklernas vävnad minskar eller förtvinas helt. Det finns två huvudtyper av muskelatrofi. Inaktivitetsatrofi orsakas av brist på fysisk aktivitet då musklerna inte ofta används eller har begränsad rörelse. Den andra, allvarligare, typen av muskelatrofi är neurogen atrofi. Den orsakas då en sjukdom eller skada påverkar nerven som fäster till musklen och kan uppstå väldigt plötsligt.
Beroende på orsak kan muskelatrofi uppstå i en muskel, en grupp av muskler eller i hela kroppen, och kan medfölja domningar, smärta och svullnad och andra neuromuskulära symptom och hudsymptom.
Orsaker
Vanliga orsaker till inaktivitetsatrofi är lite eller ingen fysisk rörelse eller en stillasittande livsstil. Men även sjukdomar, som reumatoid artrit (RA) och artros, och skador, som benskador och brännskador, som påverkar en individs rörelseförmåga kan vara orsaker till inaktivitetsatrofi. Åldrande kan även leda till en långsam men progressiv muskelatrofi.
Neurogen atrofi orsakas av skadade nerver. Neuromuskulära sjukdomar som spinal muskelatrofi (SMA), multipel skleros (MS), amyotrofisk lateralskleros (ALS) och Guillain-Barrés syndrom (GBS) är vanliga orsaker till neurogen muskelatrofi. Diabetisk neuropati, en nervskada associerad med diabetes, kan även bidra till muskelatrofi.
Symtom
Den första symptomen som uppstår vid muskelatrofi är att musklerna blir svaga och slappa. Detta upptäcks oftast då musklerna inte sitter där de brukar eller att det är svårare att utöva vardagliga rörelser som annars är relativt enkla.
Vid neurogen atrofi kan en patient se en krokig hållning vid den skadade muskeln. Denna hållning tenderar att bli mer tydlig med tiden då skadan försämras.
Båda formerna av muskelatrofi kan ge symptom som ständig ryggsmärta och svårigheter att gå. Även symptom som begränsad nackrörelse (nackspärr) och stel ryggrad utvecklas då patientens tillstånd förvärras.
I extrema fall kan patienter utveckla hjärtsvikt på grund av muskelatrofi. När musklerna blir svaga blir det svårare för hjärtat att pumpa lika effektivt och kommer till sluta att svikta.
Behandling
Beroende på vilken typ av muskelatrofi varierar behandlingen betydligt. I de flesta fall av inaktivitetsatrofi hjälper träning och motion patienterna att förbättra sina muskler, men vid neurogen atrofi behövs en eller flera behandlingsmetoder. Ibland ordineras mediciner och ibland krävs kirurgiska ingrepp. Dessa mediciner innehåller oftast antiinflammatoriska medel som kortikosteroider för att minska eventuell inflammation och avbelasta de påverkade nerverna. Men vid exempelvis diskbråck är kirurgiska ingrepp mer lämpligt. Vid neurogen muskelatrofi kan även manipulering av muskler och skelett behövas för att avbelasta nerver vid ryggraden.
Se även
Stillasittande
Förslitningsskador
Träningsintolerans
Myalgi, artralgi, neuralgi
Referenser
Fotnoter
Muskelsjukdomar
Medicinska symtom
Atrofi | swedish | 0.795717 |
ring_finger_not_move/Littlefinger.txt | Jump to content
Main menu
Main menu
move to sidebar hide
Navigation
* [ Main page ](/wiki/Main_Page "Visit the main page \[z\]")
* [ Contents ](/wiki/Wikipedia:Contents "Guides to browsing Wikipedia")
* [ Current events ](/wiki/Portal:Current_events "Articles related to current events")
* [ Random article ](/wiki/Special:Random "Visit a randomly selected article \[x\]")
* [ About Wikipedia ](/wiki/Wikipedia:About "Learn about Wikipedia and how it works")
* [ Contact us ](//en.wikipedia.org/wiki/Wikipedia:Contact_us "How to contact Wikipedia")
* [ Donate ](https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en "Support us by donating to the Wikimedia Foundation")
Contribute
* [ Help ](/wiki/Help:Contents "Guidance on how to use and edit Wikipedia")
* [ Learn to edit ](/wiki/Help:Introduction "Learn how to edit Wikipedia")
* [ Community portal ](/wiki/Wikipedia:Community_portal "The hub for editors")
* [ Recent changes ](/wiki/Special:RecentChanges "A list of recent changes to Wikipedia \[r\]")
* [ Upload file ](/wiki/Wikipedia:File_upload_wizard "Add images or other media for use on Wikipedia")
[ 
 
](/wiki/Main_Page)
[ Search ](/wiki/Special:Search "Search Wikipedia \[f\]")
Search
* [ Create account ](/w/index.php?title=Special:CreateAccount&returnto=Little+finger "You are encouraged to create an account and log in; however, it is not mandatory")
* [ Log in ](/w/index.php?title=Special:UserLogin&returnto=Little+finger "You're encouraged to log in; however, it's not mandatory. \[o\]")
Personal tools
* [ Create account ](/w/index.php?title=Special:CreateAccount&returnto=Little+finger "You are encouraged to create an account and log in; however, it is not mandatory")
* [ Log in ](/w/index.php?title=Special:UserLogin&returnto=Little+finger "You're encouraged to log in; however, it's not mandatory. \[o\]")
Pages for logged out editors [ learn more ](/wiki/Help:Introduction)
* [ Contributions ](/wiki/Special:MyContributions "A list of edits made from this IP address \[y\]")
* [ Talk ](/wiki/Special:MyTalk "Discussion about edits from this IP address \[n\]")
## Contents
move to sidebar hide
* (Top)
* 1 Etymology
* 2 Nerves and muscles
* 3 Cultural significance Toggle Cultural significance subsection
* 3.1 Gestures
* 3.2 Rings
* 3.3 Utility
* 4 See also
* 5 References
* 6 External links
Toggle the table of contents
# Little finger
74 languages
* [ العربية ](https://ar.wikipedia.org/wiki/%D8%AE%D9%86%D8%B5%D8%B1 "خنصر – Arabic")
* [ Aragonés ](https://an.wikipedia.org/wiki/Curr%C3%ADn "Currín – Aragonese")
* [ ܐܪܡܝܐ ](https://arc.wikipedia.org/wiki/%DC%9A%DC%A8%DC%AA%DC%90 "ܚܨܪܐ – Aramaic")
* [ अवधी ](https://awa.wikipedia.org/wiki/%E0%A4%95%E0%A4%A8%E0%A4%BF%E0%A4%B7%E0%A5%8D%E0%A4%A0%E0%A4%BE "कनिष्ठा – Awadhi")
* [ Авар ](https://av.wikipedia.org/wiki/%D0%93%D1%8C%D0%B8%D1%82%D3%80%D0%B8%D0%BD%D0%BA%D0%B8%D0%BB%D0%B8%D1%89 "ГьитӀинкилищ – Avaric")
* [ বাংলা ](https://bn.wikipedia.org/wiki/%E0%A6%95%E0%A6%A8%E0%A6%BF%E0%A6%B7%E0%A7%8D%E0%A6%A0%E0%A6%BE "কনিষ্ঠা – Bangla")
* [ 閩南語 / Bân-lâm-gú ](https://zh-min-nan.wikipedia.org/wiki/B%C3%B3e-ch%C3%A1i%E2%81%BF "Bóe-cháiⁿ – Minnan")
* [ Bikol Central ](https://bcl.wikipedia.org/wiki/Gigis "Gigis – Central Bikol")
* [ Български ](https://bg.wikipedia.org/wiki/%D0%9A%D1%83%D1%82%D1%80%D0%B5 "Кутре – Bulgarian")
* [ Bosanski ](https://bs.wikipedia.org/wiki/Mali_prst "Mali prst – Bosnian")
* [ Brezhoneg ](https://br.wikipedia.org/wiki/Biz-bihan "Biz-bihan – Breton")
* [ Català ](https://ca.wikipedia.org/wiki/Dit_petit "Dit petit – Catalan")
* [ Чӑвашла ](https://cv.wikipedia.org/wiki/%D0%9A%D0%B0%D1%87%D0%B0_%D0%BF%D3%B3%D1%80%D0%BD%D0%B5 "Кача пӳрне – Chuvash")
* [ Čeština ](https://cs.wikipedia.org/wiki/Mal%C3%AD%C4%8Dek "Malíček – Czech")
* [ Deutsch ](https://de.wikipedia.org/wiki/Kleiner_Finger "Kleiner Finger – German")
* [ ދިވެހިބަސް ](https://dv.wikipedia.org/wiki/%DE%86%DE%AA%DE%91%DE%A6%DE%88%DE%A6%DE%87%DE%A8_%DE%87%DE%A8%DE%82%DE%8E%DE%A8%DE%8D%DE%A8 "ކުޑަވައި އިނގިލި – Divehi")
* [ Эрзянь ](https://myv.wikipedia.org/wiki/%D0%92%D0%B5%D0%B6%D0%B0%D1%81%D1%8C%D0%BA%D0%B5 "Вежаське – Erzya")
* [ Español ](https://es.wikipedia.org/wiki/Me%C3%B1ique_de_la_mano "Meñique de la mano – Spanish")
* [ Esperanto ](https://eo.wikipedia.org/wiki/Etfingro "Etfingro – Esperanto")
* [ Euskara ](https://eu.wikipedia.org/wiki/Hatz_txiki "Hatz txiki – Basque")
* [ فارسی ](https://fa.wikipedia.org/wiki/%D8%A7%D9%86%DA%AF%D8%B4%D8%AA_%DA%A9%D9%88%DA%86%DA%A9 "انگشت کوچک – Persian")
* [ Français ](https://fr.wikipedia.org/wiki/Auriculaire_\(anatomie\) "Auriculaire \(anatomie\) – French")
* [ Frysk ](https://fy.wikipedia.org/wiki/Pink "Pink – Western Frisian")
* [ Gaeilge ](https://ga.wikipedia.org/wiki/L%C3%BAid%C3%ADn "Lúidín – Irish")
* [ Gàidhlig ](https://gd.wikipedia.org/wiki/L%C3%B9dag "Lùdag – Scottish Gaelic")
* [ Galego ](https://gl.wikipedia.org/wiki/Dedo_maimi%C3%B1o "Dedo maimiño – Galician")
* [ ગુજરાતી ](https://gu.wikipedia.org/wiki/%E0%AA%95%E0%AA%A8%E0%AB%80%E0%AA%B7%E0%AB%8D%E0%AA%A0%E0%AA%BF%E0%AA%95%E0%AA%BE "કનીષ્ઠિકા – Gujarati")
* [ 한국어 ](https://ko.wikipedia.org/wiki/%EC%83%88%EB%81%BC%EC%86%90%EA%B0%80%EB%9D%BD "새끼손가락 – Korean")
* [ Հայերեն ](https://hy.wikipedia.org/wiki/%D5%83%D5%AF%D5%B8%D6%82%D5%B5%D5%A9 "Ճկույթ – Armenian")
* [ हिन्दी ](https://hi.wikipedia.org/wiki/%E0%A4%95%E0%A4%A8%E0%A4%BF%E0%A4%B7%E0%A5%8D%E0%A4%A0%E0%A4%BE "कनिष्ठा – Hindi")
* [ Bahasa Indonesia ](https://id.wikipedia.org/wiki/Jari_kelingking "Jari kelingking – Indonesian")
* [ Italiano ](https://it.wikipedia.org/wiki/Mignolo "Mignolo – Italian")
* [ עברית ](https://he.wikipedia.org/wiki/%D7%96%D7%A8%D7%AA "זרת – Hebrew")
* [ Jawa ](https://jv.wikipedia.org/wiki/Jenthik "Jenthik – Javanese")
* [ Kiswahili ](https://sw.wikipedia.org/wiki/Kidole_cha_mwisho "Kidole cha mwisho – Swahili")
* [ Кырык мары ](https://mrj.wikipedia.org/wiki/%D0%9A%D3%93%D0%B7%D3%93%D0%B2%D0%B0%D1%80%D0%BD%D1%8F "Кӓзӓварня – Western Mari")
* [ Лакку ](https://lbe.wikipedia.org/wiki/%D0%91%D0%B8%D1%82%D3%80%D1%8F_%D0%BA%D3%80%D0%B8%D1%81%D1%81%D0%B0 "БитӀя кӀисса – Lak")
* [ Latina ](https://la.wikipedia.org/wiki/Digitus_minimus "Digitus minimus – Latin")
* [ Latviešu ](https://lv.wikipedia.org/wiki/Mazais_pirksti%C5%86%C5%A1 "Mazais pirkstiņš – Latvian")
* [ Ligure ](https://lij.wikipedia.org/wiki/Marmelin "Marmelin – Ligurian")
* [ Lombard ](https://lmo.wikipedia.org/wiki/Didin "Didin – Lombard")
* [ മലയാളം ](https://ml.wikipedia.org/wiki/%E0%B4%9A%E0%B5%86%E0%B4%B1%E0%B4%BF%E0%B4%AF_%E0%B4%B5%E0%B4%BF%E0%B4%B0%E0%B5%BD "ചെറിയ വിരൽ – Malayalam")
* [ मराठी ](https://mr.wikipedia.org/wiki/%E0%A4%95%E0%A4%B0%E0%A4%82%E0%A4%97%E0%A4%B3%E0%A5%80 "करंगळी – Marathi")
* [ Bahasa Melayu ](https://ms.wikipedia.org/wiki/Jari_kelengkeng "Jari kelengkeng – Malay")
* [ Nederlands ](https://nl.wikipedia.org/wiki/Pink_\(vinger\) "Pink \(vinger\) – Dutch")
* [ नेपाली ](https://ne.wikipedia.org/wiki/%E0%A4%95%E0%A4%BE%E0%A4%A8%E0%A5%8D%E0%A4%9B%E0%A5%80_%E0%A4%94%E0%A4%81%E0%A4%B2%E0%A4%BE "कान्छी औँला – Nepali")
* [ 日本語 ](https://ja.wikipedia.org/wiki/%E5%B0%8F%E6%8C%87 "小指 – Japanese")
* [ Norsk bokmål ](https://no.wikipedia.org/wiki/Lillefinger "Lillefinger – Norwegian Bokmål")
* [ Occitan ](https://oc.wikipedia.org/wiki/Det_pichon "Det pichon – Occitan")
* [ Pangasinan ](https://pag.wikipedia.org/wiki/Kiking "Kiking – Pangasinan")
* [ پنجابی ](https://pnb.wikipedia.org/wiki/%DA%86%DB%8C%DA%86%DB%8C "چیچی – Western Punjabi")
* [ Polski ](https://pl.wikipedia.org/wiki/Palec_ma%C5%82y "Palec mały – Polish")
* [ Português ](https://pt.wikipedia.org/wiki/Dedo_m%C3%ADnimo "Dedo mínimo – Portuguese")
* [ Русский ](https://ru.wikipedia.org/wiki/%D0%9C%D0%B8%D0%B7%D0%B8%D0%BD%D0%B5%D1%86 "Мизинец – Russian")
* [ संस्कृतम् ](https://sa.wikipedia.org/wiki/%E0%A4%95%E0%A4%A8%E0%A4%BF%E0%A4%B7%E0%A5%8D%E0%A4%A0%E0%A4%BF%E0%A4%95%E0%A4%BE "कनिष्ठिका – Sanskrit")
* [ ᱥᱟᱱᱛᱟᱲᱤ ](https://sat.wikipedia.org/wiki/%E1%B1%A5%E1%B1%A4%E1%B1%A1_%E1%B1%A0%E1%B1%9F%E1%B1%B9%E1%B1%B4%E1%B1%A9%E1%B1%B5 "ᱥᱤᱡ ᱠᱟᱹᱴᱩᱵ – Santali")
* [ Slovenčina ](https://sk.wikipedia.org/wiki/Mal%C3%AD%C4%8Dek "Malíček – Slovak")
* [ Soomaaliga ](https://so.wikipedia.org/wiki/Faryar "Faryar – Somali")
* [ کوردی ](https://ckb.wikipedia.org/wiki/%D8%AA%D9%88%D8%AA%DB%95 "توتە – Central Kurdish")
* [ Српски / srpski ](https://sr.wikipedia.org/wiki/%D0%9C%D0%B0%D0%BB%D0%B8_%D0%BF%D1%80%D1%81%D1%82 "Мали прст – Serbian")
* [ Sunda ](https://su.wikipedia.org/wiki/Cingir "Cingir – Sundanese")
* [ Suomi ](https://fi.wikipedia.org/wiki/Pikkusormi "Pikkusormi – Finnish")
* [ Svenska ](https://sv.wikipedia.org/wiki/Lillfinger "Lillfinger – Swedish")
* [ தமிழ் ](https://ta.wikipedia.org/wiki/%E0%AE%9A%E0%AF%81%E0%AE%A3%E0%AF%8D%E0%AE%9F%E0%AF%81_%E0%AE%B5%E0%AE%BF%E0%AE%B0%E0%AE%B2%E0%AF%8D "சுண்டு விரல் – Tamil")
* [ Türkçe ](https://tr.wikipedia.org/wiki/Ser%C3%A7e_parmak "Serçe parmak – Turkish")
* [ Тыва дыл ](https://tyv.wikipedia.org/wiki/%D0%A8%D1%8B%D0%BC%D0%B0%D1%88_%D1%8D%D1%80%D0%B3%D0%B5%D0%BA "Шымаш эргек – Tuvinian")
* [ Українська ](https://uk.wikipedia.org/wiki/%D0%9C%D1%96%D0%B7%D0%B8%D0%BD%D0%B5%D1%86%D1%8C "Мізинець – Ukrainian")
* [ اردو ](https://ur.wikipedia.org/wiki/%D8%AE%D9%86%D8%B5%D8%B1 "خنصر – Urdu")
* [ ئۇيغۇرچە / Uyghurche ](https://ug.wikipedia.org/wiki/%DA%86%D9%89%D9%85%DB%95%D9%84%D8%AA%DB%95%D9%83 "چىمەلتەك – Uyghur")
* [ Tiếng Việt ](https://vi.wikipedia.org/wiki/Ng%C3%B3n_tay_%C3%BAt "Ngón tay út – Vietnamese")
* [ Winaray ](https://war.wikipedia.org/wiki/Tamuyingking "Tamuyingking – Waray")
* [ 吴语 ](https://wuu.wikipedia.org/wiki/%E5%B0%8F%E6%8C%87 "小指 – Wu")
* [ 粵語 ](https://zh-yue.wikipedia.org/wiki/%E6%89%8B%E6%8C%87%E5%B1%98 "手指屘 – Cantonese")
* [ 中文 ](https://zh.wikipedia.org/wiki/%E5%B0%8F%E6%8C%87 "小指 – Chinese")
[ Edit links
](https://www.wikidata.org/wiki/Special:EntityPage/Q228027#sitelinks-wikipedia
"Edit interlanguage links")
* [ Article ](/wiki/Little_finger "View the content page \[c\]")
* [ Talk ](/wiki/Talk:Little_finger "Discuss improvements to the content page \[t\]")
English
* [ Read ](/wiki/Little_finger)
* [ Edit ](/w/index.php?title=Little_finger&action=edit "Edit this page \[e\]")
* [ View history ](/w/index.php?title=Little_finger&action=history "Past revisions of this page \[h\]")
Tools
Tools
move to sidebar hide
Actions
* [ Read ](/wiki/Little_finger)
* [ Edit ](/w/index.php?title=Little_finger&action=edit "Edit this page \[e\]")
* [ View history ](/w/index.php?title=Little_finger&action=history)
General
* [ What links here ](/wiki/Special:WhatLinksHere/Little_finger "List of all English Wikipedia pages containing links to this page \[j\]")
* [ Related changes ](/wiki/Special:RecentChangesLinked/Little_finger "Recent changes in pages linked from this page \[k\]")
* [ Upload file ](/wiki/Wikipedia:File_Upload_Wizard "Upload files \[u\]")
* [ Special pages ](/wiki/Special:SpecialPages "A list of all special pages \[q\]")
* [ Permanent link ](/w/index.php?title=Little_finger&oldid=1216431396 "Permanent link to this revision of this page")
* [ Page information ](/w/index.php?title=Little_finger&action=info "More information about this page")
* [ Cite this page ](/w/index.php?title=Special:CiteThisPage&page=Little_finger&id=1216431396&wpFormIdentifier=titleform "Information on how to cite this page")
* [ Get shortened URL ](/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FLittle_finger)
* [ Download QR code ](/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FLittle_finger)
* [ Wikidata item ](https://www.wikidata.org/wiki/Special:EntityPage/Q228027 "Structured data on this page hosted by Wikidata \[g\]")
Print/export
* [ Download as PDF ](/w/index.php?title=Special:DownloadAsPdf&page=Little_finger&action=show-download-screen "Download this page as a PDF file")
* [ Printable version ](/w/index.php?title=Little_finger&printable=yes "Printable version of this page \[p\]")
In other projects
* [ Wikimedia Commons ](https://commons.wikimedia.org/wiki/Category:Little_fingers)
From Wikipedia, the free encyclopedia
Smallest finger of the human hand
For the fictional character from _A Song of Ice and Fire_ and _Game of
Thrones_ , see [ Littlefinger ](/wiki/Littlefinger "Littlefinger") .
Little finger
---
[
 ](/wiki/File:Little_finger.jpg)
Human little finger
Details
[ Artery ](/wiki/Artery "Artery") | [ Proper palmar digital arteries
](/wiki/Proper_palmar_digital_arteries "Proper palmar digital arteries") ,
[ dorsal digital arteries ](/wiki/Dorsal_digital_arteries_of_hand "Dorsal
digital arteries of hand")
[ Vein ](/wiki/Vein "Vein") | [ Palmar digital veins
](/wiki/Palmar_digital_veins "Palmar digital veins") ,
[ dorsal digital veins ](/wiki/Dorsal_digital_veins_of_the_hand "Dorsal
digital veins of the hand")
[ Nerve ](/wiki/Nerve "Nerve") | [ Dorsal digital nerves of ulnar nerve
](/wiki/Dorsal_digital_nerves_of_ulnar_nerve "Dorsal digital nerves of ulnar
nerve")
[ Lymph ](/wiki/Lymph "Lymph") | [ supratrochlear
](/wiki/Supratrochlear_lymph_nodes "Supratrochlear lymph nodes")
Identifiers
[ Latin ](/wiki/Latin "Latin") | _digitus minimus manus,
digitus quintus manus,
digitus V manus _
[ TA98 ](/wiki/Terminologia_Anatomica "Terminologia Anatomica") | [
A01.1.00.057
](https://ifaa.unifr.ch/Public/EntryPage/TA98%20Tree/Entity%20TA98%20EN/01.1.00.057%20Entity%20TA98%20EN.htm)
[ TA2 ](/wiki/Terminologia_Anatomica "Terminologia Anatomica") | [ 155
](https://ta2viewer.openanatomy.org/?id=155)
[ FMA ](/wiki/Foundational_Model_of_Anatomy "Foundational Model of Anatomy") |
[ 24949
](https://bioportal.bioontology.org/ontologies/FMA/?p=classes&conceptid=http%3A%2F%2Fpurl.org%2Fsig%2Font%2Ffma%2Ffma24949)
[ Anatomical terminology ](/wiki/Anatomical_terminology "Anatomical
terminology")
[ [ edit on Wikidata ](https://www.wikidata.org/wiki/Q228027 "d:Q228027") ]
The **little finger** or **pinkie** , also known as the **baby finger** ,
**fifth digit** , or **pinky finger** , is the most [ ulnar
](/wiki/Anatomical_terms_of_location#Hands_and_feet "Anatomical terms of
location") and smallest digit of the human [ hand ](/wiki/Hand "Hand") , and
next to the [ ring finger ](/wiki/Ring_finger "Ring finger") .
## Etymology [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=1 "Edit section:
Etymology") ]
The word "pinkie" is derived from the [ Dutch ](/wiki/Dutch_language "Dutch
language") word [ _pink_ ](https://en.wiktionary.org/wiki/pink#Dutch
"wikt:pink") , meaning "little finger".
The earliest recorded use of the term "pinkie" is from [ Scotland
](/wiki/Scotland "Scotland") in 1808. [1] The term (sometimes spelled
"pinky") is common in [ Scottish English ](/wiki/Scottish_English "Scottish
English") [2] and [ American English ](/wiki/American_English "American
English") , [3] and is also used extensively in other Commonwealth countries
such as New Zealand, Canada, and Australia. [4] [5]
## Nerves and muscles [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=2 "Edit section: Nerves
and muscles") ]
The little finger is nearly impossible for most people to bend independently
(without also bending the ring finger), due to the nerves for each digit being
intertwined. [ _[ citation needed ](/wiki/Wikipedia:Citation_needed
"Wikipedia:Citation needed") _ ] There are also nine muscles that control the
fifth digit: Three in the [ hypothenar eminence ](/wiki/Hypothenar_eminence
"Hypothenar eminence") , two extrinsic flexors, two extrinsic extensors, and
two more intrinsic muscles:
* Hypothenar eminence:
* [ Opponens digiti minimi muscle ](/wiki/Opponens_digiti_minimi_muscle "Opponens digiti minimi muscle")
* [ Abductor minimi digiti muscle ](/wiki/Abductor_minimi_digiti_muscle_\(hand\) "Abductor minimi digiti muscle \(hand\)") ( [ adduction ](/wiki/Adduction "Adduction") from third [ palmar interossei ](/wiki/Palmar_interossei_muscles "Palmar interossei muscles") )
* [ Flexor digiti minimi brevis ](/wiki/Flexor_digiti_minimi_brevis_\(hand\) "Flexor digiti minimi brevis \(hand\)") (the "longus" is absent in most humans)
* Two extrinsic flexors:
* [ Flexor digitorum superficialis ](/wiki/Flexor_digitorum_superficialis "Flexor digitorum superficialis")
* [ Flexor digitorum profundus ](/wiki/Flexor_digitorum_profundus "Flexor digitorum profundus")
* Two extrinsic extensors:
* [ Extensor digiti minimi muscle ](/wiki/Extensor_digiti_minimi_muscle "Extensor digiti minimi muscle")
* [ Extensor digitorum ](/wiki/Extensor_digitorum "Extensor digitorum")
* Two intrinsic hand muscles:
* Fourth [ lumbrical muscle ](/wiki/Lumbricals_of_the_hand "Lumbricals of the hand")
* Third [ palmar interosseous muscle ](/wiki/Palmar_interossei "Palmar interossei")
_Note: the[ dorsal interossei of the hand
](/wiki/Dorsal_interossei_of_the_hand "Dorsal interossei of the hand") muscles
do not have an attachment to the fifth digit _
## Cultural significance [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=3 "Edit section:
Cultural significance") ]
### Gestures [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=4 "Edit section:
Gestures") ]
[
 ](/wiki/File:Pinky_swear.JPG) Pinky promise
Among American children, a " [ pinky swear ](/wiki/Pinky_swear "Pinky swear")
" or "pinky promise" is made when a person wraps one of their pinky fingers
around another person's pinky and makes a [ promise ](/wiki/Promise "Promise")
. [6] Something similar is also seen in China and Korea, where people link
their pinky fingers and then stamp their thumbs together to make a _yaksok_
(promise).
Among members of the [ Japanese ](/wiki/Japan "Japan") _[ yakuza
](/wiki/Yakuza "Yakuza") _ (gangsters), the penalty for various offenses is
removal of parts of the little finger (known as _[ yubitsume ](/wiki/Yubitsume
"Yubitsume") _ ). [7]
It is a common misconception that one should extend their little finger when
drinking from a teacup. This practice is generally deprecated by etiquette
guides as a sign of snobbery amongst the socially inferior, [8] [9] with
various cultural theories as to the origin of the practice including the idea
that finger food should be eaten with only the first three digits. [10]
The messaging application Teams from Microsoft [11] has an emoji which is a
representation of a closed hand with the little finger raised. The description
is "Nature's call" which is a polite euphemism used when someone feels a need
to urinate or defecate. [12]
### Rings [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=5 "Edit section:
Rings") ]
[
 ](/wiki/File:Signet_and_Wedding_rings.jpg)
Signet ring (little finger) and wedding ring (ring finger) on a left hand
The [ signet ring ](/wiki/Signet_ring "Signet ring") is traditionally worn on
the little finger of a gentleman's left hand, a practice still common
especially in the [ United Kingdom ](/wiki/United_Kingdom "United Kingdom") ,
[ Australia ](/wiki/Australia "Australia") , and European cultures. A signet
ring is considered part of the regalia of many European monarchies, and also
of the Pope, with the ring always worn on the left little finger. In modern
times the location of the signet ring has relaxed, with examples worn on
various different digits, although little fingers still tend to be the most
usual.
The [ Iron Ring ](/wiki/Iron_Ring "Iron Ring") is a symbolic ring worn by most
[ Canadian engineers ](/wiki/Canadian_engineers "Canadian engineers") . The
Ring is a symbol of both pride and humility for the engineering profession,
and is always worn on the little finger of the [ dominant hand
](/wiki/Dominant_hand "Dominant hand") . In the [ United States
](/wiki/United_States "United States") , the [ Engineer's Ring
](/wiki/Engineer%27s_Ring "Engineer's Ring") is a [ stainless steel
](/wiki/Stainless_steel "Stainless steel") ring worn on the fifth digit of the
working hand by engineers who belong to the [ Order of the Engineer
](/wiki/Order_of_the_Engineer "Order of the Engineer") [13] and have accepted
the Obligation of an Engineer. [14]
### Utility [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=6 "Edit section:
Utility") ]
The little finger is often used as a support when [ smartphone
](/wiki/Smartphone "Smartphone") users type one-handed. The little finger is
positioned underneath the phone, allowing it to be propped with the three
middle fingers, and the user to type with their thumb. [15]
Some users reported dents on their little finger and pain in the hand after
prolonged use in this way, doctors referred to this as "iPhone pinky" or
"smartphone pinky". The skin indentations were reported to be nothing of
alarm, as they disappeared on their own after a short while without cell phone
use. [15] [16]
## See also [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=7 "Edit section: See
also") ]
* [ Finger numbering ](/wiki/Finger_numbering "Finger numbering")
* [ Fifth metacarpal bone ](/wiki/Fifth_metacarpal_bone "Fifth metacarpal bone") , the bone in the hand proximal to the little finger
* [ Pinky ring ](/wiki/Pinky_ring "Pinky ring") , a ring worn on the little finger
* [ Red string of fate ](/wiki/Red_string_of_fate "Red string of fate") , a Chinese belief that soulmates are bound by a string attached to the little finger
## References [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=8 "Edit section:
References") ]
1. ** ^ ** [ "Pinkie" ](http://www.worldwidewords.org/qa/qa-pin1.htm) . World Wide Words . Retrieved 25 July 2018 .
2. ** ^ ** [ "Scots word of the season: pinkie" ](https://www.thebottleimp.org.uk/2008/05/scots-word-of-the-season-pinkie/) . Association for Scottish Literary Studies. May 2008 . Retrieved 28 January 2020 .
3. ** ^ ** [ "Little Finger" ](https://dictionary.cambridge.org/dictionary/english/little-finger) . Cambridge English Dictionary . Retrieved 26 July 2019 .
4. ** ^ ** Arthurs, Deborah; Gladwell, Hattie (21 January 2016). [ "Has your smartphone given you 'smartphone pinky'?" ](https://metro.co.uk/2016/01/21/has-your-smartphone-given-you-smartphone-pinky-5636739/) . _Metro_ . Retrieved 6 April 2020 .
5. ** ^ ** Barrie, Joshua (15 February 2018). [ "Woman cuts off finger, names it 'Wiggles' and wears it as pendant necklace" ](https://www.mirror.co.uk/news/weird-news/woman-cuts-finger-names-wiggles-12033539) . _The Mirror_ . Retrieved 6 April 2020 . " A woman cut off half her pinky finger and now wears it as a pendant around her neck. "
6. ** ^ ** Roud, Steve. [ The Lore of the Playground ](https://books.google.com/books?id=HY9I1e21AJcC&dq=%22pinky+promise%22+finger&pg=PA371) . Random House. 2010.
7. ** ^ ** Hill, Peter B. E.: "The Japanese Mafia: Yakuza, law, and the state", p. 75. [ Oxford Univ. Press ](/wiki/Oxford_University_Press "Oxford University Press") , 2003
8. ** ^ ** [ "Tea Etiquette" ](http://www.tealaden.com/teaweb/etiquette.htm) . Tea Laden . Retrieved 28 July 2018 .
9. ** ^ ** [ "Etiquette and History of Afternoon Tea" ](https://web.archive.org/web/20180729012827/https://www.afternoontoremember.com/learn/etiquette) . An Afternoon to Remember. Archived from [ the original ](https://www.afternoontoremember.com/learn/etiquette) on Jul 29, 2018 . Retrieved 28 July 2018 .
10. ** ^ ** Arden (2014-11-21). [ "Raised pinky fingers, scone slicing and other tea faux pas" ](https://www.cliseetiquette.com/raised-pinky-fingers-scone-slicing-tea-faux-pas/) . _Clise Etiquette_ . Retrieved 2020-03-10 .
11. ** ^ ** [ "View all available emojis in Microsoft Teams (free)" ](https://support.microsoft.com/en-us/office/view-all-available-emojis-b9c2ccda-9ad9-4dbb-a25d-bbcebf6311ae) . _Microsoft Support_ . Retrieved 2021-06-02 .
12. ** ^ ** Mark_N13 (8 Feb 2018). [ "Emoji" ](https://answers.microsoft.com/en-us/skype/forum/all/emoji/232bd680-e84f-44cf-8532-71129070dc91) . _Microsoft Community_ . [ Archived ](https://web.archive.org/web/20231215222643/https://answers.microsoft.com/en-us/skype/forum/all/emoji/232bd680-e84f-44cf-8532-71129070dc91) from the original on Dec 15, 2023 . Retrieved 2022-03-27 .
13. ** ^ ** [ "Engineer's Ring" ](https://web.archive.org/web/20200216095337/http://www.order-of-the-engineer.org/?page_id=10) . _Order Of The Engineer_ . Archived from [ the original ](http://www.order-of-the-engineer.org/?page_id=10) on Feb 16, 2020.
14. ** ^ ** [ "Obligation" ](https://web.archive.org/web/20200214213805/http://www.order-of-the-engineer.org:80/?page_id=6) . _Order Of The Engineer_ . Archived from [ the original ](http://www.order-of-the-engineer.org/?page_id=6) on Feb 14, 2020.
15. ^ _**a** _ _**b** _ Schlitz, Heather (Nov 6, 2021). [ "People are sharing pictures of their dented 'smartphone pinky' after holding their phones, so asked doctors what the deal is" ](https://www.businessinsider.com/smartphone-pinky-finger-dents-not-permanent-damaging-doctors-say-2021-11) . _Business Insider_ . Retrieved 2022-04-13 .
16. ** ^ ** Chiu, Allyson (Oct 29, 2021). [ "How to avoid 'smartphone pinkie' and other pains and problems from being glued to your phone" ](https://www.washingtonpost.com/lifestyle/2021/10/29/smartphone-pinky-hand-pain/) . _Washington Post_ . [ ISSN ](/wiki/ISSN_\(identifier\) "ISSN \(identifier\)") [ 0190-8286 ](https://www.worldcat.org/issn/0190-8286) . [ Archived ](https://web.archive.org/web/20230306221037/https://www.washingtonpost.com/lifestyle/2021/10/29/smartphone-pinky-hand-pain/) from the original on Mar 6, 2023 . Retrieved 2022-04-13 .
## External links [ [ edit
](/w/index.php?title=Little_finger&action=edit§ion=9 "Edit section:
External links") ]
* [  ](/wiki/File:Commons-logo.svg) Media related to [ Little fingers ](https://commons.wikimedia.org/wiki/Category:Little_fingers "commons:Category:Little fingers") at Wikimedia Commons
* [  ](/wiki/File:Wiktionary-logo-en-v2.svg) The dictionary definition of [ _little finger_ ](https://en.wiktionary.org/wiki/Special:Search/little_finger "wiktionary:Special:Search/little finger") at Wiktionary
* [ v ](/wiki/Template:Human_regional_anatomy "Template:Human regional anatomy")
* [ t ](/wiki/Template_talk:Human_regional_anatomy "Template talk:Human regional anatomy")
* [ e ](/wiki/Special:EditPage/Template:Human_regional_anatomy "Special:EditPage/Template:Human regional anatomy")
[ Human regional anatomy ](/wiki/Human_body#Regional_groups "Human body")
---
[ Body ](/wiki/Human_body "Human body") |
[ Skin ](/wiki/Human_skin "Human skin")
[ Head ](/wiki/Human_head "Human head") |
* [ Hair ](/wiki/Hair "Hair")
* [ Face ](/wiki/Face "Face")
* [ Forehead ](/wiki/Forehead "Forehead")
* [ Cheek ](/wiki/Cheek "Cheek")
* [ Chin ](/wiki/Chin "Chin")
* [ Eyebrow ](/wiki/Eyebrow "Eyebrow")
* [ Eye ](/wiki/Human_eye "Human eye")
* [ Eyelid ](/wiki/Eyelid "Eyelid")
* [ Nose ](/wiki/Human_nose "Human nose")
* [ Mouth ](/wiki/Human_mouth "Human mouth")
* [ Lip ](/wiki/Lip "Lip")
* [ Tongue ](/wiki/Tongue "Tongue")
* [ Teeth ](/wiki/Human_tooth "Human tooth")
* [ Ear ](/wiki/Ear "Ear")
* [ Jaw ](/wiki/Jaw "Jaw")
* [ Mandible ](/wiki/Mandible "Mandible")
* [ Occiput ](/wiki/Occipital_bone "Occipital bone")
* [ Scalp ](/wiki/Scalp "Scalp")
* [ Temple ](/wiki/Temple_\(anatomy\) "Temple \(anatomy\)")
[ Neck ](/wiki/Neck "Neck") |
* [ Adam's apple ](/wiki/Adam%27s_apple "Adam's apple")
* [ Throat ](/wiki/Throat "Throat")
* [ Nape ](/wiki/Nape "Nape")
[ Torso ](/wiki/Torso "Torso") (Trunk) |
* [ Abdomen ](/wiki/Abdomen "Abdomen")
* [ Waist ](/wiki/Waist "Waist")
* [ Midriff ](/wiki/Midriff "Midriff")
* [ Navel ](/wiki/Navel "Navel")
* [ Vertebral column ](/wiki/Vertebral_column "Vertebral column")
* [ Back ](/wiki/Human_back "Human back")
* [ Thorax ](/wiki/Thorax "Thorax")
* [ Breast ](/wiki/Breast "Breast")
* [ Nipple ](/wiki/Nipple "Nipple")
* [ Pelvis ](/wiki/Pelvis "Pelvis")
* [ Genitalia ](/wiki/Sex_organ "Sex organ")
* [ Penis ](/wiki/Human_penis "Human penis")
* [ Scrotum ](/wiki/Scrotum "Scrotum")
* [ Vulva ](/wiki/Vulva "Vulva")
* [ Anus ](/wiki/Human_anus "Human anus")
[ Limbs ](/wiki/Limb_\(anatomy\) "Limb \(anatomy\)") |
| [ Arm ](/wiki/Arm "Arm") |
* [ Shoulder ](/wiki/Shoulder "Shoulder")
* [ Axilla ](/wiki/Axilla "Axilla")
* [ Elbow ](/wiki/Elbow "Elbow")
* [ Forearm ](/wiki/Forearm "Forearm")
* [ Wrist ](/wiki/Wrist "Wrist")
* [ Hand ](/wiki/Hand "Hand")
* [ Finger ](/wiki/Finger "Finger")
* [ Fingernail ](/wiki/Nail_\(anatomy\) "Nail \(anatomy\)")
* [ Thumb ](/wiki/Thumb "Thumb")
* [ Index ](/wiki/Index_finger "Index finger")
* [ Middle ](/wiki/Middle_finger "Middle finger")
* [ Ring ](/wiki/Ring_finger "Ring finger")
* Little
---|---
[ Leg ](/wiki/Human_leg "Human leg") |
* [ Buttocks ](/wiki/Buttocks "Buttocks")
* [ Hip ](/wiki/Hip "Hip")
* [ Thigh ](/wiki/Thigh "Thigh")
* [ Knee ](/wiki/Knee "Knee")
* [ Calf ](/wiki/Calf_\(leg\) "Calf \(leg\)")
* [ Foot ](/wiki/Foot "Foot")
* [ Ankle ](/wiki/Ankle "Ankle")
* [ Heel ](/wiki/Heel "Heel")
* [ Toe ](/wiki/Toe "Toe")
* [ Toenail ](/wiki/Nail_\(anatomy\) "Nail \(anatomy\)")
* [ Sole ](/wiki/Sole_\(foot\) "Sole \(foot\)")
[ Authority control databases ](/wiki/Help:Authority_control "Help:Authority
control") [ 
](https://www.wikidata.org/wiki/Q228027#identifiers "Edit this at Wikidata") |
* [ Terminologia Anatomica ](http://tools.wmflabs.org/wikidata-externalid-url/?p=1323&url_prefix=https:%2F%2Fwww.unifr.ch%2Fifaa%2FPublic%2FEntryPage%2FTA98%20Tree%2FEntity%20TA98%20EN%2F&url_suffix=%20Entity%20TA98%20EN.htm&id=A01.1.00.057)
---|---
Retrieved from " [
https://en.wikipedia.org/w/index.php?title=Little_finger&oldid=1216431396
](https://en.wikipedia.org/w/index.php?title=Little_finger&oldid=1216431396) "
[ Categories ](/wiki/Help:Category "Help:Category") :
* [ Fingers ](/wiki/Category:Fingers "Category:Fingers")
* [ Human anatomy ](/wiki/Category:Human_anatomy "Category:Human anatomy")
Hidden categories:
* [ Articles with short description ](/wiki/Category:Articles_with_short_description "Category:Articles with short description")
* [ Short description matches Wikidata ](/wiki/Category:Short_description_matches_Wikidata "Category:Short description matches Wikidata")
* [ All articles with unsourced statements ](/wiki/Category:All_articles_with_unsourced_statements "Category:All articles with unsourced statements")
* [ Articles with unsourced statements from October 2021 ](/wiki/Category:Articles_with_unsourced_statements_from_October_2021 "Category:Articles with unsourced statements from October 2021")
* [ Commons category link is on Wikidata ](/wiki/Category:Commons_category_link_is_on_Wikidata "Category:Commons category link is on Wikidata")
* [ Articles with TA98 identifiers ](/wiki/Category:Articles_with_TA98_identifiers "Category:Articles with TA98 identifiers")
* This page was last edited on 30 March 2024, at 23:45 (UTC) .
* Text is available under the [ Creative Commons Attribution-ShareAlike License 4.0 ](//en.wikipedia.org/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License) [ ](//en.wikipedia.org/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License) ; additional terms may apply. By using this site, you agree to the [ Terms of Use ](//foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use) and [ Privacy Policy ](//foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy) . Wikipedia® is a registered trademark of the [ Wikimedia Foundation, Inc. ](//www.wikimediafoundation.org/) , a non-profit organization.
* [ Privacy policy ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy)
* [ About Wikipedia ](/wiki/Wikipedia:About)
* [ Disclaimers ](/wiki/Wikipedia:General_disclaimer)
* [ Contact Wikipedia ](//en.wikipedia.org/wiki/Wikipedia:Contact_us)
* [ Code of Conduct ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct)
* [ Developers ](https://developer.wikimedia.org)
* [ Statistics ](https://stats.wikimedia.org/#/en.wikipedia.org)
* [ Cookie statement ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement)
* [ Mobile view ](//en.m.wikipedia.org/w/index.php?title=Little_finger&mobileaction=toggle_view_mobile)
* [  ](https://wikimediafoundation.org/)
* [  ](https://www.mediawiki.org/)
* Toggle limited content width
*[
v
]: View this template
*[
t
]: Discuss this template
*[
e
]: Edit this template
| biology | 16215 | https://sv.wikipedia.org/wiki/Wikiprogramvara | Wikiprogramvara | Wikiprogramvara är den serverprogramvara som används för att driva en wiki på en webbplats. Programvaran anropas vanligen av själva webbservern genom CGI-gränssnittet, och innehåller funktioner som gör att det är lätt att ändra i webbsidorna, se hur en viss webbsida utvecklats, och återställa äldre versioner.
Den första wikiprogramvaran skapades av Ward Cunningham. Idag finns det ett stort antal olika.
Ett alternativ till att installera wikiprogramvara på en egen server är att använda ett wikihotell (eng. wiki farm eller wiki hosting service). Exempel på wikihotell med svenskt användargränssnitt är Wikia, Mindtouch, Zoho Wiki och skolwiki.
Exempel på wikiprogram
De mest populära indelade efter programspråk.
ASP
LambdaWiki
OpenWiki
PHP
WikkaWiki - http://wikkawiki.org/
PHP Wiki - http://phpwiki.sourceforge.net/
Tavi -
WackoWiki - http://wackowiki.org/
Wakka -
MediaWiki -
DokuWiki - https://web.archive.org/web/20080419135955/http://wiki.splitbrain.org/wiki:dokuwiki
PmWiki - http://www.pmwiki.org/
Perl
Chiq chaq -
Twiki - http://twiki.org
UseModWiki
Oddmuse
Python
MoinMoin - http://moinmoin.wikiwikiweb.de/
Zim - https://zim-wiki.org/
Övriga (programspråk)
Swiki - https://web.archive.org/web/20030806052355/http://minnow.cc.gatech.edu/swiki/ Squeak Smalltalk
CFWiki - Cold Fusion
och JavaScript
CLiki - Common Lisp
JSPWiki - JSP
Pike Wiki - Pike
InterWiki - http://www.usemod.com/cgi-bin/mb.pl?InterWiki
TipiWiki - https://web.archive.org/web/20030607014855/http://andi.dasstellenwirinsinternet.de/tipiwiki/index.php?wiki=FrontPage
Zwiki - http://www.zwiki.org/
SnipSnap - http://www.snipsnap.org
Generic Applications Server
Se även
Wiki
de:Wiki-Software | swedish | 0.969618 |
ring_finger_not_move/Extrinsic_extensor_muscles_of_the_hand.txt | The extrinsic extensor muscles of the hand are located in the back of the forearm and have long tendons connecting them to bones in the hand, where they exert their action. Extrinsic denotes their location outside the hand. Extensor denotes their action which is to extend, or open flat, joints in the hand. They include the extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB), extensor digitorum (ED), extensor digiti minimi (EDM), extensor carpi ulnaris (ECU), abductor pollicis longus (APL), extensor pollicis brevis (EPB), extensor pollicis longus (EPL), and extensor indicis (EI).
Origin[edit]
The extensor carpi radialis longus (ECRL) has the most proximal origin of the extrinsic hand extensors. It originates just distal to the brachioradialis at the lateral supracondylar ridge of the humerus, the lateral intermuscular septum, and by a few fibers at the lateral epicondyle of the humerus. Distal to this, the extensor carpi radialis brevis (ECRB), extensor digitorum, extensor digiti minimi, and extensor carpi ulnaris (ECU) originate from the lateral epicondyle via the common extensor tendon. The ECRB has additional origins from the radial collateral ligament, the ECU from the dorsal border of the ulna (shared with the flexor carpi ulnaris and flexor digitorum profundus), and all four also originate from various fascia. Moving distally, there are the abductor pollicis longus (APL), extensor pollicis brevis (EPB), extensor pollicis longus (EPL), and extensor indicis (EI). The APL originates from the lateral part of the dorsal surface of the body of the ulna below the insertion of the anconeus and from the middle third of the dorsal surface of the body of the radius. The EPB arises from the radius distal to the APL and from the dorsal surface of the radius. The EPL arises from the dorsal surface of the ulna and the EI from the distal third of the dorsal part of the body of ulna. The APL, EPB, EPL, and EI all have an additional origin at the interosseus membrane.
Course[edit]
The ECRL and ECRB, (with the brachioradialis) form the lateral compartment. Their muscle fibers end at the upper third and the mid forearm respectively, continuing as flat tendons along the lateral border of the radius, beneath the APL and EPB. They then pass beneath the extensor retinaculum and dorsal carpal ligament, where they lie in a groove on the back of the radius, immediately behind the styloid process, and continue into the second tendon compartment. The ED divides into four tendons which, with the EI tendons, go through the fourth tendon compartment of the dorsal carpal ligament. On the back of the hand, the ED tendons diverge to follow the fingers and the EI tendon joins the ulnar side of one of the ED tendons along the back of the index finger. The EDM takes a similar course as the EI except it follows the ED tendon along the little finger. The ECU crosses from the lateral to the medial side of the forearm. The APL and EPB pass obliquely down and lateral, ending in tendons which run through a groove on the lateral side of the lower end of the radius. The EPL tendon passes through the third compartment and lies in a narrow, oblique groove on the back of the lower end of the radius.
Extensor digitorum tendons[edit]
The ED tendons are more complex in their course. Opposite the metacarpophalangeal joint each tendon is bound by fasciculi to the collateral ligaments and serves as the dorsal ligament of this joint; after having crossed the joint, it spreads out into a broad aponeurosis, which covers the dorsal surface of the first phalanx and is reinforced, in this situation, by the tendons of the Interossei and Lumbricalis.
Opposite the first interphalangeal joints this aponeurosis divides into three slips; an intermediate and two collateral: the former is inserted into the base of the second phalanx; and the two collateral, which are continued onward along the sides of the second phalanx, unite by their contiguous margins, and are inserted into the dorsal surface of the last phalanx. As the tendons cross the interphalangeal joints, they furnish them with dorsal ligaments. The tendon to the index finger is accompanied by the EI, which lies on its ulnar side. On the back of the hand, the tendons to the middle, ring, and little fingers are connected by two obliquely placed bands, one from the third tendon passing downward and lateralward to the second tendon, and the other passing from the same tendon downward and medialward to the fourth.
Occasionally the first tendon is connected to the second by a thin transverse band. Collectively, these are known as the sagittal bands; they serve to maintain the central alignment of the extensor tendons over the metacarpal head, thus increasing the available leverage. Injuries (such as by an external flexion force during active extension) may allow the tendon to dislocate into the intermetacarpal space; the extensor tendon then acts as a flexor and the finger may no longer be actively extended. This may be corrected surgically by using a slip of the extensor tendon to replace the damaged ligamentous band
Anatomical snuff box[edit]
Main article: anatomical snuff box
The EPL tendon crosses obliquely the tendons of the ECRL and ECRB, and is separated from the EPB by a triangular interval, the anatomical snuff box, in which the radial artery is found.
Insertion and action[edit]
Insertions
The ECRL inserts into the dorsal surface of the base of the second metacarpal bone on its radial side to extend and abduct the wrist. The ECRB inserts into the lateral dorsal surface of the base of the third metacarpal bone, with a few fibres inserting into the medial dorsal surface of the second metacarpal bone, also to extend and abduct the wrist. The ED inserts into the middle and distal phalanges to extend the fingers and wrist. Opposite the head of the second metacarpal bone, the EI joins the ulnar side of the ED tendon to extend the index finger. The EDM has a similar role for the little finger. The ECU inserts at the base of the 5th metacarpal to extend and adduct the wrist. The APL inserts into the radial side of the base of the first metacarpal bone to abduct the thumb at the carpometacarpal joint and may continue to abduct the wrist. The EPB inserts into the base of the first phalanx of the thumb to extend and abduct the thumb at the carpometacarpal and MCP joints.
The EPL inserts on the base of the distal phalanx of the thumb. It uses the dorsal tubercle on the radius as fulcrum to help the EPB with its action as well as extending the distal phalanx of the thumb. Because the index finger and little finger have separate extensors, these fingers can be moved more independently than the other fingers.
Neurovascular supply[edit]
The ECU is supplied by the ulnar artery. The APL, EPB, EPL, EI, ED, and EDM are supplied by the Posterior interosseous artery, a branch of the ulnar artery. The ECRL and ECRB receive blood from the radial artery.
The ECRL is supplied by the radial nerve and the ECRB by its deep branch. The remaining extrinsic hand extensors are supplied by the posterior interosseus nerve, another branch of the radial nerve.
Summary table[edit]
Muscle
Origin
Insertion
Artery
Nerve
Action
Antagonist
Gray's
Extensor carpi radialis longus
lateral supracondylar ridge
2nd metacarpal, base
radial
radial
extends, abducts wrist
FCRM
s125p452
Extensor carpi radialis brevis
common extensor tendon
3rd metacarpal, base
radial nerve, deep branch
Extensor digitorum
extensor expansion of 2nd–5th middle, distal phalanges
posterior interosseus
posterior interosseus
extends fingers, wrist
FDS, FDP
s125p451
Extensor digiti minimi
extensor expansion, base of proximal phalanx, little finger
extends little finger at all joints
FDMB
Extensor carpi ulnaris
common extensor tendon, ulna
5th metacarpal, base
ulnar
extends, adducts wrist
FCU
s125p454
Abductor pollicis longus
ulna, radius, interosseous membrane
first metacarpal, base
posterior interosseus
abducts, extends thumb
AP
s125p455
Extensor pollicis brevis
proximal phalanx, thumb
extends thumb at MCP joint
FPL, FPB
Extensor pollicis longus
ulna, interosseous membrane
thumb, distal phalanx
extends thumb at MCP and IP joint
FPL, FPB
Extensor indicis
index finger, extensor hood
extends index finger, wrist
See also[edit]
Extensor digitorum reflex | biology | 2390293 | https://sv.wikipedia.org/wiki/Etropus%20ectenes | Etropus ectenes | Etropus ectenes är en fiskart som beskrevs av Jordan, 1889. Etropus ectenes ingår i släktet Etropus och familjen Paralichthyidae. IUCN kategoriserar arten globalt som livskraftig. Inga underarter finns listade i Catalogue of Life.
Källor
Plattfiskar
ectenes | swedish | 0.928252 |
ring_finger_not_move/Ringfinger.txt | Jump to content
Main menu
Main menu
move to sidebar hide
Navigation
* [ Main page ](/wiki/Main_Page "Visit the main page \[z\]")
* [ Contents ](/wiki/Wikipedia:Contents "Guides to browsing Wikipedia")
* [ Current events ](/wiki/Portal:Current_events "Articles related to current events")
* [ Random article ](/wiki/Special:Random "Visit a randomly selected article \[x\]")
* [ About Wikipedia ](/wiki/Wikipedia:About "Learn about Wikipedia and how it works")
* [ Contact us ](//en.wikipedia.org/wiki/Wikipedia:Contact_us "How to contact Wikipedia")
* [ Donate ](https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en "Support us by donating to the Wikimedia Foundation")
Contribute
* [ Help ](/wiki/Help:Contents "Guidance on how to use and edit Wikipedia")
* [ Learn to edit ](/wiki/Help:Introduction "Learn how to edit Wikipedia")
* [ Community portal ](/wiki/Wikipedia:Community_portal "The hub for editors")
* [ Recent changes ](/wiki/Special:RecentChanges "A list of recent changes to Wikipedia \[r\]")
* [ Upload file ](/wiki/Wikipedia:File_upload_wizard "Add images or other media for use on Wikipedia")
[ 
 
](/wiki/Main_Page)
[ Search ](/wiki/Special:Search "Search Wikipedia \[f\]")
Search
* [ Create account ](/w/index.php?title=Special:CreateAccount&returnto=Ring+finger "You are encouraged to create an account and log in; however, it is not mandatory")
* [ Log in ](/w/index.php?title=Special:UserLogin&returnto=Ring+finger "You're encouraged to log in; however, it's not mandatory. \[o\]")
Personal tools
* [ Create account ](/w/index.php?title=Special:CreateAccount&returnto=Ring+finger "You are encouraged to create an account and log in; however, it is not mandatory")
* [ Log in ](/w/index.php?title=Special:UserLogin&returnto=Ring+finger "You're encouraged to log in; however, it's not mandatory. \[o\]")
Pages for logged out editors [ learn more ](/wiki/Help:Introduction)
* [ Contributions ](/wiki/Special:MyContributions "A list of edits made from this IP address \[y\]")
* [ Talk ](/wiki/Special:MyTalk "Discussion about edits from this IP address \[n\]")
## Contents
move to sidebar hide
* (Top)
* 1 Etymology
* 2 History
* 3 Contemporary customs Toggle Contemporary customs subsection
* 3.1 Western customs
* 3.2 Middle Eastern, Jewish, and Asian customs
* 4 See also
* 5 References
* 6 External links
Toggle the table of contents
# Ring finger
66 languages
* [ अंगिका ](https://anp.wikipedia.org/wiki/%E0%A4%85%E0%A4%A8%E0%A4%BE%E0%A4%AE%E0%A4%BF%E0%A4%95%E0%A4%BE_%E0%A4%94%E0%A4%82%E0%A4%97%E0%A4%B0%E0%A5%80 "अनामिका औंगरी – Angika")
* [ العربية ](https://ar.wikipedia.org/wiki/%D8%A8%D9%86%D8%B5%D8%B1 "بنصر – Arabic")
* [ Aragonés ](https://an.wikipedia.org/wiki/Dido_anular "Dido anular – Aragonese")
* [ ܐܪܡܝܐ ](https://arc.wikipedia.org/wiki/%DC%92%DC%A8%DC%AA%DC%90_\(%DC%A8%DC%92%DC%A5%DC%90\) "ܒܨܪܐ \(ܨܒܥܐ\) – Aramaic")
* [ अवधी ](https://awa.wikipedia.org/wiki/%E0%A4%85%E0%A4%A8%E0%A4%BE%E0%A4%AE%E0%A4%BF%E0%A4%95%E0%A4%BE "अनामिका – Awadhi")
* [ বাংলা ](https://bn.wikipedia.org/wiki/%E0%A6%85%E0%A6%A8%E0%A6%BE%E0%A6%AE%E0%A6%BF%E0%A6%95%E0%A6%BE_\(%E0%A6%B6%E0%A6%BE%E0%A6%B0%E0%A7%80%E0%A6%B0%E0%A6%B8%E0%A7%8D%E0%A6%A5%E0%A6%BE%E0%A6%A8\) "অনামিকা \(শারীরস্থান\) – Bangla")
* [ 閩南語 / Bân-lâm-gú ](https://zh-min-nan.wikipedia.org/wiki/B%C3%B3e-j%C4%AB-ch%C3%A1i%E2%81%BF "Bóe-jī-cháiⁿ – Minnan")
* [ Bikol Central ](https://bcl.wikipedia.org/wiki/Singsingan "Singsingan – Central Bikol")
* [ Български ](https://bg.wikipedia.org/wiki/%D0%91%D0%B5%D0%B7%D0%B8%D0%BC%D0%B5%D0%BD_%D0%BF%D1%80%D1%8A%D1%81%D1%82 "Безимен пръст – Bulgarian")
* [ Bosanski ](https://bs.wikipedia.org/wiki/Prstenjak "Prstenjak – Bosnian")
* [ Brezhoneg ](https://br.wikipedia.org/wiki/Biz-gwalenn "Biz-gwalenn – Breton")
* [ Català ](https://ca.wikipedia.org/wiki/Anular "Anular – Catalan")
* [ Чӑвашла ](https://cv.wikipedia.org/wiki/%D0%AF%D1%82%D1%81%C4%83%D1%80_%D0%BF%D3%B3%D1%80%D0%BD%D0%B5 "Ятсăр пӳрне – Chuvash")
* [ Čeština ](https://cs.wikipedia.org/wiki/Prsten%C3%ADk "Prsteník – Czech")
* [ Deutsch ](https://de.wikipedia.org/wiki/Ringfinger "Ringfinger – German")
* [ ދިވެހިބަސް ](https://dv.wikipedia.org/wiki/%DE%86%DE%A6%DE%81%DE%A8_%DE%87%DE%A8%DE%82%DE%8E%DE%A8%DE%8D%DE%A8 "ކަށި އިނގިލި – Divehi")
* [ Español ](https://es.wikipedia.org/wiki/Dedo_anular "Dedo anular – Spanish")
* [ Esperanto ](https://eo.wikipedia.org/wiki/Ringofingro "Ringofingro – Esperanto")
* [ Euskara ](https://eu.wikipedia.org/wiki/Hatz_nagi "Hatz nagi – Basque")
* [ فارسی ](https://fa.wikipedia.org/wiki/%D8%A7%D9%86%DA%AF%D8%B4%D8%AA_%D8%AD%D9%84%D9%82%D9%87 "انگشت حلقه – Persian")
* [ Français ](https://fr.wikipedia.org/wiki/Annulaire_\(anatomie\) "Annulaire \(anatomie\) – French")
* [ Frysk ](https://fy.wikipedia.org/wiki/Ringfinger "Ringfinger – Western Frisian")
* [ Gàidhlig ](https://gd.wikipedia.org/wiki/Mac_an_aba "Mac an aba – Scottish Gaelic")
* [ Galego ](https://gl.wikipedia.org/wiki/Dedo_anular "Dedo anular – Galician")
* [ ગુજરાતી ](https://gu.wikipedia.org/wiki/%E0%AA%85%E0%AA%A8%E0%AA%BE%E0%AA%AE%E0%AA%BF%E0%AA%95%E0%AA%BE "અનામિકા – Gujarati")
* [ 한국어 ](https://ko.wikipedia.org/wiki/%EC%95%BD%EC%86%90%EA%B0%80%EB%9D%BD "약손가락 – Korean")
* [ Հայերեն ](https://hy.wikipedia.org/wiki/%D5%84%D5%A1%D5%BF%D5%B6%D5%A5%D5%B4%D5%A1%D5%BF "Մատնեմատ – Armenian")
* [ हिन्दी ](https://hi.wikipedia.org/wiki/%E0%A4%85%E0%A4%A8%E0%A4%BE%E0%A4%AE%E0%A4%BF%E0%A4%95%E0%A4%BE_\(%E0%A4%85%E0%A4%82%E0%A4%97%E0%A5%81%E0%A4%B2%E0%A5%80\) "अनामिका \(अंगुली\) – Hindi")
* [ Bahasa Indonesia ](https://id.wikipedia.org/wiki/Jari_manis "Jari manis – Indonesian")
* [ Italiano ](https://it.wikipedia.org/wiki/Anulare "Anulare – Italian")
* [ עברית ](https://he.wikipedia.org/wiki/%D7%A7%D7%9E%D7%99%D7%A6%D7%94_\(%D7%90%D7%A6%D7%91%D7%A2\) "קמיצה \(אצבע\) – Hebrew")
* [ Jawa ](https://jv.wikipedia.org/wiki/Driji_manis "Driji manis – Javanese")
* [ Kiswahili ](https://sw.wikipedia.org/wiki/Kidole_cha_kati_cha_kando "Kidole cha kati cha kando – Swahili")
* [ Latina ](https://la.wikipedia.org/wiki/Anularius "Anularius – Latin")
* [ Latviešu ](https://lv.wikipedia.org/wiki/Zeltnesis "Zeltnesis – Latvian")
* [ Ligure ](https://lij.wikipedia.org/wiki/Anul%C3%A2 "Anulâ – Ligurian")
* [ Lombard ](https://lmo.wikipedia.org/wiki/Sposin "Sposin – Lombard")
* [ मराठी ](https://mr.wikipedia.org/wiki/%E0%A4%85%E0%A4%A8%E0%A4%BE%E0%A4%AE%E0%A4%BF%E0%A4%95%E0%A4%BE "अनामिका – Marathi")
* [ Bahasa Melayu ](https://ms.wikipedia.org/wiki/Jari_manis "Jari manis – Malay")
* [ Nederlands ](https://nl.wikipedia.org/wiki/Ringvinger "Ringvinger – Dutch")
* [ नेपाली ](https://ne.wikipedia.org/wiki/%E0%A4%B8%E0%A4%BE%E0%A4%B9%E0%A4%BF%E0%A4%B2%E0%A5%80_%E0%A4%94%E0%A4%81%E0%A4%B2%E0%A4%BE "साहिली औँला – Nepali")
* [ 日本語 ](https://ja.wikipedia.org/wiki/%E8%96%AC%E6%8C%87 "薬指 – Japanese")
* [ Norsk bokmål ](https://no.wikipedia.org/wiki/Ringfinger "Ringfinger – Norwegian Bokmål")
* [ Occitan ](https://oc.wikipedia.org/wiki/Anular_\(anatomia\) "Anular \(anatomia\) – Occitan")
* [ Polski ](https://pl.wikipedia.org/wiki/Palec_serdeczny "Palec serdeczny – Polish")
* [ Português ](https://pt.wikipedia.org/wiki/Anular "Anular – Portuguese")
* [ Русский ](https://ru.wikipedia.org/wiki/%D0%91%D0%B5%D0%B7%D1%8B%D0%BC%D1%8F%D0%BD%D0%BD%D1%8B%D0%B9_%D0%BF%D0%B0%D0%BB%D0%B5%D1%86 "Безымянный палец – Russian")
* [ संस्कृतम् ](https://sa.wikipedia.org/wiki/%E0%A4%85%E0%A4%A8%E0%A4%BE%E0%A4%AE%E0%A4%BF%E0%A4%95%E0%A4%BE "अनामिका – Sanskrit")
* [ ᱥᱟᱱᱛᱟᱲᱤ ](https://sat.wikipedia.org/wiki/%E1%B1%A2%E1%B1%A9%E1%B1%AB%E1%B1%9F%E1%B1%B9%E1%B1%A2_%E1%B1%A0%E1%B1%9F%E1%B1%B9%E1%B1%B4%E1%B1%A9%E1%B1%B5 "ᱢᱩᱫᱟᱹᱢ ᱠᱟᱹᱴᱩᱵ – Santali")
* [ Slovenčina ](https://sk.wikipedia.org/wiki/Prstenn%C3%ADk "Prstenník – Slovak")
* [ Soomaaliga ](https://so.wikipedia.org/wiki/Faraanti_galis_\(far\) "Faraanti galis \(far\) – Somali")
* [ کوردی ](https://ckb.wikipedia.org/wiki/%D8%A8%D8%B1%D8%A7%DB%8C_%D8%AA%D9%88%D8%AA%DB%95 "برای توتە – Central Kurdish")
* [ Српски / srpski ](https://sr.wikipedia.org/wiki/%D0%94%D0%BE%D0%BC%D0%B0%D0%BB%D0%B8_%D0%BF%D1%80%D1%81%D1%82 "Домали прст – Serbian")
* [ Sunda ](https://su.wikipedia.org/wiki/Jariji "Jariji – Sundanese")
* [ Suomi ](https://fi.wikipedia.org/wiki/Nimet%C3%B6n "Nimetön – Finnish")
* [ Svenska ](https://sv.wikipedia.org/wiki/Ringfinger "Ringfinger – Swedish")
* [ தமிழ் ](https://ta.wikipedia.org/wiki/%E0%AE%AE%E0%AF%8B%E0%AE%A4%E0%AE%BF%E0%AE%B0_%E0%AE%B5%E0%AE%BF%E0%AE%B0%E0%AE%B2%E0%AF%8D "மோதிர விரல் – Tamil")
* [ ไทย ](https://th.wikipedia.org/wiki/%E0%B8%99%E0%B8%B4%E0%B9%89%E0%B8%A7%E0%B8%99%E0%B8%B2%E0%B8%87 "นิ้วนาง – Thai")
* [ Türkçe ](https://tr.wikipedia.org/wiki/Y%C3%BCz%C3%BCk_parma%C4%9F%C4%B1 "Yüzük parmağı – Turkish")
* [ Українська ](https://uk.wikipedia.org/wiki/%D0%9F%D1%96%D0%B4%D0%BC%D1%96%D0%B7%D0%B8%D0%BD%D0%BD%D0%B8%D0%B9_%D0%BF%D0%B0%D0%BB%D0%B5%D1%86%D1%8C "Підмізинний палець – Ukrainian")
* [ اردو ](https://ur.wikipedia.org/wiki/%DA%86%D9%88%D8%AA%DA%BE%DB%8C_%D8%A7%D9%86%DA%AF%D9%84%DB%8C "چوتھی انگلی – Urdu")
* [ ئۇيغۇرچە / Uyghurche ](https://ug.wikipedia.org/wiki/%D9%86%D8%A7%D9%85%D8%B3%D9%89%D8%B2_%D8%A8%D8%A7%D8%B1%D9%85%D8%A7%D9%82 "نامسىز بارماق – Uyghur")
* [ Winaray ](https://war.wikipedia.org/wiki/Singsingan "Singsingan – Waray")
* [ 吴语 ](https://wuu.wikipedia.org/wiki/%E6%97%A0%E5%90%8D%E6%8C%87 "无名指 – Wu")
* [ 粵語 ](https://zh-yue.wikipedia.org/wiki/%E7%84%A1%E5%90%8D%E6%8C%87 "無名指 – Cantonese")
* [ 中文 ](https://zh.wikipedia.org/wiki/%E7%84%A1%E5%90%8D%E6%8C%87 "無名指 – Chinese")
[ Edit links
](https://www.wikidata.org/wiki/Special:EntityPage/Q192298#sitelinks-wikipedia
"Edit interlanguage links")
* [ Article ](/wiki/Ring_finger "View the content page \[c\]")
* [ Talk ](/wiki/Talk:Ring_finger "Discuss improvements to the content page \[t\]")
English
* [ Read ](/wiki/Ring_finger)
* [ Edit ](/w/index.php?title=Ring_finger&action=edit "Edit this page \[e\]")
* [ View history ](/w/index.php?title=Ring_finger&action=history "Past revisions of this page \[h\]")
Tools
Tools
move to sidebar hide
Actions
* [ Read ](/wiki/Ring_finger)
* [ Edit ](/w/index.php?title=Ring_finger&action=edit "Edit this page \[e\]")
* [ View history ](/w/index.php?title=Ring_finger&action=history)
General
* [ What links here ](/wiki/Special:WhatLinksHere/Ring_finger "List of all English Wikipedia pages containing links to this page \[j\]")
* [ Related changes ](/wiki/Special:RecentChangesLinked/Ring_finger "Recent changes in pages linked from this page \[k\]")
* [ Upload file ](/wiki/Wikipedia:File_Upload_Wizard "Upload files \[u\]")
* [ Special pages ](/wiki/Special:SpecialPages "A list of all special pages \[q\]")
* [ Permanent link ](/w/index.php?title=Ring_finger&oldid=1218888187 "Permanent link to this revision of this page")
* [ Page information ](/w/index.php?title=Ring_finger&action=info "More information about this page")
* [ Cite this page ](/w/index.php?title=Special:CiteThisPage&page=Ring_finger&id=1218888187&wpFormIdentifier=titleform "Information on how to cite this page")
* [ Get shortened URL ](/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FRing_finger)
* [ Download QR code ](/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FRing_finger)
* [ Wikidata item ](https://www.wikidata.org/wiki/Special:EntityPage/Q192298 "Structured data on this page hosted by Wikidata \[g\]")
Print/export
* [ Download as PDF ](/w/index.php?title=Special:DownloadAsPdf&page=Ring_finger&action=show-download-screen "Download this page as a PDF file")
* [ Printable version ](/w/index.php?title=Ring_finger&printable=yes "Printable version of this page \[p\]")
In other projects
* [ Wikimedia Commons ](https://commons.wikimedia.org/wiki/Category:Ring_fingers)
From Wikipedia, the free encyclopedia
Third from the thumb finger of a human hand
[  ](/wiki/File:Question_book-new.svg)
|
This article **needs additional citations for[ verification
](/wiki/Wikipedia:Verifiability "Wikipedia:Verifiability") ** . Please help [
improve this article ](/wiki/Special:EditPage/Ring_finger
"Special:EditPage/Ring finger") by [ adding citations to reliable sources
](/wiki/Help:Referencing_for_beginners "Help:Referencing for beginners") .
Unsourced material may be challenged and removed.
_Find sources:_ [ "Ring finger"
](https://www.google.com/search?as_eq=wikipedia&q=%22Ring+finger%22) – [ news
](https://www.google.com/search?tbm=nws&q=%22Ring+finger%22+-wikipedia&tbs=ar:1)
**·** [ newspapers
](https://www.google.com/search?&q=%22Ring+finger%22&tbs=bkt:s&tbm=bks) **·**
[ books
](https://www.google.com/search?tbs=bks:1&q=%22Ring+finger%22+-wikipedia)
**·** [ scholar ](https://scholar.google.com/scholar?q=%22Ring+finger%22)
**·** [ JSTOR
](https://www.jstor.org/action/doBasicSearch?Query=%22Ring+finger%22&acc=on&wc=on)
_( December 2022 ) _ _( [ Learn how and when to remove this message
](/wiki/Help:Maintenance_template_removal "Help:Maintenance template removal")
) _
---|---
Ring finger
---
[
 ](/wiki/File:Ringvinger.jpg)
A left human hand with the ring finger extended
Details
[ Artery ](/wiki/Artery "Artery") | [ Proper palmar digital arteries
](/wiki/Proper_palmar_digital_arteries "Proper palmar digital arteries") ,
[ dorsal digital arteries ](/wiki/Dorsal_digital_arteries_of_hand "Dorsal
digital arteries of hand")
[ Vein ](/wiki/Vein "Vein") | [ Palmar digital veins
](/wiki/Palmar_digital_veins "Palmar digital veins") , [ dorsal digital veins
](/wiki/Dorsal_venous_network_of_hand "Dorsal venous network of hand")
[ Nerve ](/wiki/Nerve "Nerve") | [ Dorsal digital nerves of radial nerve
](/wiki/Dorsal_digital_nerves_of_radial_nerve "Dorsal digital nerves of radial
nerve") ,
[ Dorsal digital nerves of ulnar nerve
](/wiki/Dorsal_digital_nerves_of_ulnar_nerve "Dorsal digital nerves of ulnar
nerve") ,
[ Proper palmar digital nerves of median nerve
](/wiki/Proper_palmar_digital_nerves_of_median_nerve "Proper palmar digital
nerves of median nerve")
Identifiers
[ Latin ](/wiki/Latin "Latin") | _digitus IV manus, digitus quartus manus,
digitus annularis manus, digitus medicinalis_
[ TA98 ](/wiki/Terminologia_Anatomica "Terminologia Anatomica") | [
A01.1.00.056
](https://ifaa.unifr.ch/Public/EntryPage/TA98%20Tree/Entity%20TA98%20EN/01.1.00.056%20Entity%20TA98%20EN.htm)
[ TA2 ](/wiki/Terminologia_Anatomica "Terminologia Anatomica") | [ 154
](https://ta2viewer.openanatomy.org/?id=154)
[ FMA ](/wiki/Foundational_Model_of_Anatomy "Foundational Model of Anatomy") |
[ 24948
](https://bioportal.bioontology.org/ontologies/FMA/?p=classes&conceptid=http%3A%2F%2Fpurl.org%2Fsig%2Font%2Ffma%2Ffma24948)
[ Anatomical terminology ](/wiki/Anatomical_terminology "Anatomical
terminology")
[ [ edit on Wikidata ](https://www.wikidata.org/wiki/Q192298 "d:Q192298") ]
The **ring finger** , **third finger** , [1] **fourth finger** , [2] [3]
**leech finger** , [4] or **annulary** is the fourth digit of the human
hand, located between the [ middle finger ](/wiki/Middle_finger "Middle
finger") and the [ little finger ](/wiki/Little_finger "Little finger") . [5]
Sometimes the term **ring finger** only refers to the fourth digit of a
**left-hand** , so named for its traditional association with [ wedding rings
](/wiki/Wedding_ring "Wedding ring") in many societies, although not all use
this digit as the ring finger. Traditionally, a wedding ring was worn only by
the bride or wife, but in recent times more men also wear a wedding ring. It
is also the custom in some societies to wear an [ engagement ring
](/wiki/Engagement_ring "Engagement ring") on the ring finger.
In [ anatomy ](/wiki/Anatomy "Anatomy") , the ring finger is called _digitus
medicinalis_ , _the fourth digit_ , _digitus annularis_ , _digitus quartus_ ,
or _digitus IV_ . In Latin, the word _anulus_ means "ring", _digitus_ means
"digit", and _quartus_ means "fourth".
## Etymology [ [ edit
](/w/index.php?title=Ring_finger&action=edit§ion=1 "Edit section:
Etymology") ]
The origin of the selection of the fourth digit as the ring finger is not
definitively known. According to László A. Magyar, the names of the ring
finger in many languages reflect an ancient belief that it is a magical
finger. It is named after magic or rings, or called _nameless_ (for example,
in [ Chinese ](/wiki/Chinese_language "Chinese language") : 無名指 / 无名指 ; [
pinyin ](/wiki/Pinyin "Pinyin") : _ wúmíng zhǐ _ ; lit. 'unnamed finger').
[6]
In [ Japanese ](/wiki/Japanese_language "Japanese language") , it is called
薬指 ( _kusuri yubi_ , "medicine finger"), deriving its name from the fact that
it was frequently used when taking [ traditional powdered medicine
](/wiki/Kampo "Kampo") , as it was rarely used otherwise and hence was
considered the cleanest of all. [7]
In other languages such as [ Sanskrit ](/wiki/Sanskrit "Sanskrit") , [ Finnish
](/wiki/Finnish_language "Finnish language") , and [ Russian
](/wiki/Russian_language "Russian language") , the ring finger is called
"Anamika", "nimetön", and "Безымянный" ( _bezymianny_ , "nameless"),
respectively.
In Semitic languages such as [ Arabic ](/wiki/Arabic_language "Arabic
language") and [ Hebrew ](/wiki/Hebrew_language "Hebrew language") , the ring
finger is called _bansur_ (meaning "victory") and _kmitsa_ (meaning "taking a
handful"), respectively.
## History [ [ edit ](/w/index.php?title=Ring_finger&action=edit§ion=2
"Edit section: History") ]
Main article: [ Wedding ring ](/wiki/Wedding_ring "Wedding ring")
Before [ medical science ](/wiki/Medical_science "Medical science") discovered
how the [ circulatory system ](/wiki/Circulatory_system "Circulatory system")
functioned, people believed that a vein ran directly from the fourth digit on
the left hand to the heart. [8] Because of the hand–heart connection, they
chose the descriptive name [ vena amoris ](/wiki/Vena_amoris "Vena amoris") ,
Latin for the vein of love, for this particular vein. [9]
Based upon this name, their contemporaries, purported experts in the field of
matrimonial etiquette, wrote that it would only be fitting that the wedding
ring be worn on this digit. By wearing the ring on the fourth digit of the
left hand, a married couple symbolically declares their eternal love for each
other.
In Britain, only women tended to wear a wedding ring until after the [ World
Wars ](/wiki/World_Wars "World Wars") , when married male soldiers started to
wear rings to remind them of their wife. [10]
## Contemporary customs [ [ edit
](/w/index.php?title=Ring_finger&action=edit§ion=3 "Edit section:
Contemporary customs") ]
[  ](/wiki/File:Question_book-new.svg)
|
This section **needs additional citations for[ verification
](/wiki/Wikipedia:Verifiability "Wikipedia:Verifiability") ** . Please help [
improve this article ](/wiki/Special:EditPage/Ring_finger
"Special:EditPage/Ring finger") by [ adding citations to reliable sources
](/wiki/Help:Referencing_for_beginners "Help:Referencing for beginners") in
this section. Unsourced material may be challenged and removed.
_Find sources:_ [ "Ring finger"
](https://www.google.com/search?as_eq=wikipedia&q=%22Ring+finger%22) – [ news
](https://www.google.com/search?tbm=nws&q=%22Ring+finger%22+-wikipedia&tbs=ar:1)
**·** [ newspapers
](https://www.google.com/search?&q=%22Ring+finger%22&tbs=bkt:s&tbm=bks) **·**
[ books
](https://www.google.com/search?tbs=bks:1&q=%22Ring+finger%22+-wikipedia)
**·** [ scholar ](https://scholar.google.com/scholar?q=%22Ring+finger%22)
**·** [ JSTOR
](https://www.jstor.org/action/doBasicSearch?Query=%22Ring+finger%22&acc=on&wc=on)
_( January 2024 ) _ _( [ Learn how and when to remove this message
](/wiki/Help:Maintenance_template_removal "Help:Maintenance template removal")
) _
---|---
### Western customs [ [ edit
](/w/index.php?title=Ring_finger&action=edit§ion=4 "Edit section: Western
customs") ]
[
](/wiki/File:Man_putting_engagement_ring_on_woman%27s_finger.jpg) A man
putting engagement ring on woman's finger
In [ Western cultures ](/wiki/Western_culture "Western culture") , a wedding
ring is traditionally worn on the fourth digit, commonly called the "ring
finger". This developed from the Roman _anulus pronubis_ , when a man would
give a ring to the woman at their betrothal ceremony. Blessing the wedding
ring and putting it on the bride's finger dates from the 11th century.
In medieval Europe, during the [ Christian ](/wiki/Christianity
"Christianity") wedding ceremony, the ring was placed in sequence on the
thumb, index, middle, and ring fingers of the left hand. The ring was then
left on the ring finger.
In a few European countries, the ring is worn on the left hand prior to
marriage, then transferred to the right during the ceremony. For example, an [
Eastern Orthodox Church ](/wiki/Eastern_Orthodox_Church "Eastern Orthodox
Church") bride wears the ring on the left hand prior to the ceremony, then
moves it to the right hand after the wedding. In England, the 1549 Prayer Book
declared "the ring shall be placed on the left hand". By the 17th and 18th
centuries, the ring could be found on any digit after the ceremony — even on
the thumb.
The wedding ring is generally worn on the ring finger of the left hand in the
former British Empire, certain parts of Western Europe, certain parts of
Catholic Mexico, Bolivia, Chile, and Central and Eastern Europe. These
include: Australia, Botswana, Canada, Egypt, Ireland, New Zealand, South
Africa, the UK, and the US, [11] as well as France, Italy, Portugal, Sweden,
Finland, Czech Republic, Slovakia, Switzerland, Netherlands [if Catholic],
Croatia, Slovenia, Romania, Catalonia, Valencia, and the Balearic Islands. In
Spain, the ring is generally worn on the right hand.
The wedding ring is worn on the ring finger of the right hand in some Orthodox
and a small number of Catholic European countries, some Protestant Western
European, as well as some Central and South American Catholic countries. [12]
In Eastern Europe, these include Belarus, Bulgaria, Georgia, Latvia,
Lithuania, North Macedonia, Russia, Serbia, and Ukraine. In Central or Western
Europe, these include Austria, Belgium, Denmark, Germany, Greece, Hungary,
Poland, the Netherlands (if not Catholic), Norway, and Spain (except in the
Catalan-speaking regions). In Central or South America, these include
Colombia, Cuba, Peru, and Venezuela.
In Turkey, Lebanon, Syria, Romania, and Brazil, the ring is worn on the right
hand until the actual wedding day, when it is moved to the left hand.
In western guitar music, "I-M-A" is a style of plucking guitar strings, where
"I" means index finger, "M" means middle finger, and "A" means ring finger.
This is a popular type of "finger style" guitar playing, where the "A" comes
from Latin, where the word anulus means ring. [13]
### Middle Eastern, Jewish, and Asian customs [ [ edit
](/w/index.php?title=Ring_finger&action=edit§ion=5 "Edit section: Middle
Eastern, Jewish, and Asian customs") ]
In [ Sinhalese ](/wiki/Sinhalese_people "Sinhalese people") and [ Tamil
](/wiki/Tamil_people "Tamil people") culture, the groom wears the wedding ring
on his right hand, but the bride wears it on her left hand ring finger. This
can be seen in countries like [ Sri Lanka ](/wiki/Sri_Lanka "Sri Lanka") ,
which has a rich Sinhalese and Tamil cultural influence on the society. [14]
A wedding ring is not a traditional part of the religious [ Muslim wedding
](/wiki/Muslim_wedding "Muslim wedding") , and wedding rings are not included
in most [ Islamic ](/wiki/Islam "Islam") countries. If a wedding ring is worn
in an Islamic country, however, it may be worn on either the left (such is the
custom in [ Iran ](/wiki/Iran "Iran") ) and for example (in Jordan the right
ring finger for engagement and the left ring finger for marriage). As opposed
to the wedding ring, use of a ring to denote [ _betrothal or engagement_
](/wiki/Engagement_ring "Engagement ring") is quite prevalent in Muslim
countries, especially those in West and Asia. These rings may be worn on the
ring finger of either the right or left hand by both men and women.
In a traditional [ Jewish wedding ](/wiki/Jewish_wedding "Jewish wedding")
ceremony, the wedding ring is placed on the bride's right-hand index finger,
[15] but other traditions place it on the middle finger or the thumb, most
commonly in recent times. [16] Today, the ring usually is moved to the left
hand ring finger after the ceremony. Some Jewish grooms have adopted wearing a
wedding ring, but in [ Orthodox Judaism ](/wiki/Orthodox_Judaism "Orthodox
Judaism") , most men do not wear wedding rings.
Rings are not traditional in an [ Indian wedding ](/wiki/Indian_wedding
"Indian wedding") , but in modern society, it is becoming a practice to wear
rings for engagements if not for actual marriage. Although the left hand is
considered inauspicious for religious activities, a ring (which is not called
a wedding ring) is still worn on the left hand. Men generally wear the rings
on the right hand and women on the left hands.
## See also [ [ edit
](/w/index.php?title=Ring_finger&action=edit§ion=6 "Edit section: See
also") ]
* [ Digit ratio ](/wiki/Digit_ratio "Digit ratio") , comparative lengths of the index finger and ring finger and androgen levels in utero
* [ Finger numbering ](/wiki/Finger_numbering "Finger numbering")
## References [ [ edit
](/w/index.php?title=Ring_finger&action=edit§ion=7 "Edit section:
References") ]
1. ** ^ ** [ "Synonyms of ring finger | Thesaurus.com" ](https://www.thesaurus.com/browse/ring%20finger) . _www.thesaurus.com_ . Retrieved 17 August 2022 .
2. ** ^ ** [ "ring finger" ](https://www.collinsdictionary.com/us/dictionary/english/fourth-finger) . _[ Collins English Dictionary ](/wiki/Collins_English_Dictionary "Collins English Dictionary") _ . Retrieved 17 August 2022 .
3. ** ^ ** [ "fourth finger" ](https://medical-dictionary.thefreedictionary.com/fourth+finger) . _Medical Dictionary_ . Retrieved 17 August 2022 .
4. ** ^ ** [ "How the 'Ring Finger' Got Its Name" ](https://www.merriam-webster.com/words-at-play/how-the-ring-finger-got-its-name) . _[ Merriam Webster Dictionary ](/wiki/Webster%27s_Dictionary "Webster's Dictionary") _ . Retrieved 17 August 2022 .
5. ** ^ ** [ "Synonyms of annulary | Thesaurus.com" ](https://www.thesaurus.com/browse/annulary) . _www.thesaurus.com_ . Retrieved 17 August 2022 .
6. ** ^ ** Magyar, László A. (1990). [ "Digitus Medicinalis — the Etymology of the Name" ](https://web.archive.org/web/20080123085956/http://semmelweis.tripod.com/digitus.html) . _Actes du Congr. Intern. d'Hist. de Med. XXXII., Antwerpen_ . pp. 175–179. Archived from [ the original ](http://semmelweis.tripod.com/digitus.html) on 23 January 2008 . Retrieved 2 September 2009 .
7. ** ^ ** [ "Japanese Vocabularies: Talking about human body" ](https://crunchynihongo.com/japanese-vocabularies-talking-about-human-body/) . _Crunchy Nihongo!_ . 17 September 2017.
8. ** ^ ** Kunz, George Frederick (1917). [ _Rings for the finger: from the earliest known times, to the present, with full descriptions of the origin, early making, materials, the archaeology, history, for affection, for love, for engagement, for wedding, commemorative, mourning, etc_ ](https://books.google.com/books?id=a4FCAQAAIAAJ&pg=PA194) . J. B. Lippincott company. pp. 193–194.
9. ** ^ ** Mukherji, Subha (2006), [ _Law and Representation in Early Modern Drama_ ](https://books.google.com/books?id=EO0K6F5xDv0C&pg=PA36) , Cambridge University Press, pp. 35–36, [ ISBN ](/wiki/ISBN_\(identifier\) "ISBN \(identifier\)") [ 0521850355 ](/wiki/Special:BookSources/0521850355 "Special:BookSources/0521850355")
10. ** ^ ** [ "Wedding rings: Have men always worn them?" ](https://www.bbc.co.uk/news/magazine-12986535) . _BBC_ . 8 April 2011. " World War II is considered to have heralded a seismic shift, as many Western men fighting overseas chose to wear wedding rings as a comforting reminder of their wives and families back home. "
11. ** ^ ** [ "What hand does a wedding ring go on for a man" ](https://alpinerings.com/blogs/news/what-hand-does-a-wedding-ring-go-on-for-a-man) . _Alpine Rings_ .
12. ** ^ ** [ "Why in the Orthodox tradition do we wear the wedding ring on the left hand?" ](http://www.antiochian.org/1286) . _antiochian.org_ .
13. ** ^ ** [ "Right Hand Planting Technique" ](https://douglasniedt.com/Tech_Tip_Right_Hand_Planting_Technique_Arpeggios.html) . _douglasniedt.com_ .
14. ** ^ ** [ "A Sri Lankan Tamil Hindu Wedding" ](https://web.archive.org/web/20120903212847/http://tamilculturewaterloo.org/documents/tamil_culture/srilankan_wedding_rituals.pdf) (PDF) . Archived from [ the original ](http://www.tamilculturewaterloo.org/documents/tamil_culture/srilankan_wedding_rituals.pdf) (PDF) on 3 September 2012.
15. ** ^ ** [ "Guide to the Jewish Wedding" ](http://www.aish.com/jl/l/m/48969841.html) . _aish.com_ . 9 May 2009.
16. ** ^ ** Sperber, David (1995). _Minhagei Yisrael, Jerusalem (Hebrew)_ . Vol. 4. pp. 92–93.
## External links [ [ edit
](/w/index.php?title=Ring_finger&action=edit§ion=8 "Edit section: External
links") ]
Wikimedia Commons has media related to [ Ring fingers
](https://commons.wikimedia.org/wiki/Category:Ring_fingers
"commons:Category:Ring fingers") .
Look up _**[ ring finger
](https://en.wiktionary.org/wiki/Special:Search/ring_finger
"wiktionary:Special:Search/ring finger") ** _ in Wiktionary, the free
dictionary.
* [ Archive of a 1998 article in a Flemish newspaper about the place of the wedding ring in the Low Countries ](http://s2.ned.univie.ac.at/NoN/landeskunde/be/h2/link3.htm)
* [ v ](/wiki/Template:Human_regional_anatomy "Template:Human regional anatomy")
* [ t ](/wiki/Template_talk:Human_regional_anatomy "Template talk:Human regional anatomy")
* [ e ](/wiki/Special:EditPage/Template:Human_regional_anatomy "Special:EditPage/Template:Human regional anatomy")
[ Human regional anatomy ](/wiki/Human_body#Regional_groups "Human body")
---
[ Body ](/wiki/Human_body "Human body") |
[ Skin ](/wiki/Human_skin "Human skin")
[ Head ](/wiki/Human_head "Human head") |
* [ Hair ](/wiki/Hair "Hair")
* [ Face ](/wiki/Face "Face")
* [ Forehead ](/wiki/Forehead "Forehead")
* [ Cheek ](/wiki/Cheek "Cheek")
* [ Chin ](/wiki/Chin "Chin")
* [ Eyebrow ](/wiki/Eyebrow "Eyebrow")
* [ Eye ](/wiki/Human_eye "Human eye")
* [ Eyelid ](/wiki/Eyelid "Eyelid")
* [ Nose ](/wiki/Human_nose "Human nose")
* [ Mouth ](/wiki/Human_mouth "Human mouth")
* [ Lip ](/wiki/Lip "Lip")
* [ Tongue ](/wiki/Tongue "Tongue")
* [ Teeth ](/wiki/Human_tooth "Human tooth")
* [ Ear ](/wiki/Ear "Ear")
* [ Jaw ](/wiki/Jaw "Jaw")
* [ Mandible ](/wiki/Mandible "Mandible")
* [ Occiput ](/wiki/Occipital_bone "Occipital bone")
* [ Scalp ](/wiki/Scalp "Scalp")
* [ Temple ](/wiki/Temple_\(anatomy\) "Temple \(anatomy\)")
[ Neck ](/wiki/Neck "Neck") |
* [ Adam's apple ](/wiki/Adam%27s_apple "Adam's apple")
* [ Throat ](/wiki/Throat "Throat")
* [ Nape ](/wiki/Nape "Nape")
[ Torso ](/wiki/Torso "Torso") (Trunk) |
* [ Abdomen ](/wiki/Abdomen "Abdomen")
* [ Waist ](/wiki/Waist "Waist")
* [ Midriff ](/wiki/Midriff "Midriff")
* [ Navel ](/wiki/Navel "Navel")
* [ Vertebral column ](/wiki/Vertebral_column "Vertebral column")
* [ Back ](/wiki/Human_back "Human back")
* [ Thorax ](/wiki/Thorax "Thorax")
* [ Breast ](/wiki/Breast "Breast")
* [ Nipple ](/wiki/Nipple "Nipple")
* [ Pelvis ](/wiki/Pelvis "Pelvis")
* [ Genitalia ](/wiki/Sex_organ "Sex organ")
* [ Penis ](/wiki/Human_penis "Human penis")
* [ Scrotum ](/wiki/Scrotum "Scrotum")
* [ Vulva ](/wiki/Vulva "Vulva")
* [ Anus ](/wiki/Human_anus "Human anus")
[ Limbs ](/wiki/Limb_\(anatomy\) "Limb \(anatomy\)") |
| [ Arm ](/wiki/Arm "Arm") |
* [ Shoulder ](/wiki/Shoulder "Shoulder")
* [ Axilla ](/wiki/Axilla "Axilla")
* [ Elbow ](/wiki/Elbow "Elbow")
* [ Forearm ](/wiki/Forearm "Forearm")
* [ Wrist ](/wiki/Wrist "Wrist")
* [ Hand ](/wiki/Hand "Hand")
* [ Finger ](/wiki/Finger "Finger")
* [ Fingernail ](/wiki/Nail_\(anatomy\) "Nail \(anatomy\)")
* [ Thumb ](/wiki/Thumb "Thumb")
* [ Index ](/wiki/Index_finger "Index finger")
* [ Middle ](/wiki/Middle_finger "Middle finger")
* Ring
* [ Little ](/wiki/Little_finger "Little finger")
---|---
[ Leg ](/wiki/Human_leg "Human leg") |
* [ Buttocks ](/wiki/Buttocks "Buttocks")
* [ Hip ](/wiki/Hip "Hip")
* [ Thigh ](/wiki/Thigh "Thigh")
* [ Knee ](/wiki/Knee "Knee")
* [ Calf ](/wiki/Calf_\(leg\) "Calf \(leg\)")
* [ Foot ](/wiki/Foot "Foot")
* [ Ankle ](/wiki/Ankle "Ankle")
* [ Heel ](/wiki/Heel "Heel")
* [ Toe ](/wiki/Toe "Toe")
* [ Toenail ](/wiki/Nail_\(anatomy\) "Nail \(anatomy\)")
* [ Sole ](/wiki/Sole_\(foot\) "Sole \(foot\)")
[ Authority control databases ](/wiki/Help:Authority_control "Help:Authority
control") [ 
](https://www.wikidata.org/wiki/Q192298#identifiers "Edit this at Wikidata") |
* [ Terminologia Anatomica ](http://tools.wmflabs.org/wikidata-externalid-url/?p=1323&url_prefix=https:%2F%2Fwww.unifr.ch%2Fifaa%2FPublic%2FEntryPage%2FTA98%20Tree%2FEntity%20TA98%20EN%2F&url_suffix=%20Entity%20TA98%20EN.htm&id=A01.1.00.056)
---|---
Retrieved from " [
https://en.wikipedia.org/w/index.php?title=Ring_finger&oldid=1218888187
](https://en.wikipedia.org/w/index.php?title=Ring_finger&oldid=1218888187) "
[ Category ](/wiki/Help:Category "Help:Category") :
* [ Fingers ](/wiki/Category:Fingers "Category:Fingers")
Hidden categories:
* [ Articles with short description ](/wiki/Category:Articles_with_short_description "Category:Articles with short description")
* [ Short description is different from Wikidata ](/wiki/Category:Short_description_is_different_from_Wikidata "Category:Short description is different from Wikidata")
* [ Use dmy dates from December 2022 ](/wiki/Category:Use_dmy_dates_from_December_2022 "Category:Use dmy dates from December 2022")
* [ Articles needing additional references from December 2022 ](/wiki/Category:Articles_needing_additional_references_from_December_2022 "Category:Articles needing additional references from December 2022")
* [ All articles needing additional references ](/wiki/Category:All_articles_needing_additional_references "Category:All articles needing additional references")
* [ Articles containing Chinese-language text ](/wiki/Category:Articles_containing_Chinese-language_text "Category:Articles containing Chinese-language text")
* [ Articles containing Japanese-language text ](/wiki/Category:Articles_containing_Japanese-language_text "Category:Articles containing Japanese-language text")
* [ Articles needing additional references from January 2024 ](/wiki/Category:Articles_needing_additional_references_from_January_2024 "Category:Articles needing additional references from January 2024")
* [ Commons category link is on Wikidata ](/wiki/Category:Commons_category_link_is_on_Wikidata "Category:Commons category link is on Wikidata")
* [ Articles with TA98 identifiers ](/wiki/Category:Articles_with_TA98_identifiers "Category:Articles with TA98 identifiers")
* This page was last edited on 14 April 2024, at 13:09 (UTC) .
* Text is available under the [ Creative Commons Attribution-ShareAlike License 4.0 ](//en.wikipedia.org/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License) [ ](//en.wikipedia.org/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License) ; additional terms may apply. By using this site, you agree to the [ Terms of Use ](//foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use) and [ Privacy Policy ](//foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy) . Wikipedia® is a registered trademark of the [ Wikimedia Foundation, Inc. ](//www.wikimediafoundation.org/) , a non-profit organization.
* [ Privacy policy ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy)
* [ About Wikipedia ](/wiki/Wikipedia:About)
* [ Disclaimers ](/wiki/Wikipedia:General_disclaimer)
* [ Contact Wikipedia ](//en.wikipedia.org/wiki/Wikipedia:Contact_us)
* [ Code of Conduct ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct)
* [ Developers ](https://developer.wikimedia.org)
* [ Statistics ](https://stats.wikimedia.org/#/en.wikipedia.org)
* [ Cookie statement ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement)
* [ Mobile view ](//en.m.wikipedia.org/w/index.php?title=Ring_finger&mobileaction=toggle_view_mobile)
* [  ](https://wikimediafoundation.org/)
* [  ](https://www.mediawiki.org/)
* Toggle limited content width
*[
lit.
]: Literal translation
*[
v
]: View this template
*[
t
]: Discuss this template
*[
e
]: Edit this template
| biology | 3010413 | https://sv.wikipedia.org/wiki/Euriphene%20ampedusa | Euriphene ampedusa | Euriphene ampedusa är en fjärilsart som beskrevs av William Chapman Hewitson 1866. Euriphene ampedusa ingår i släktet Euriphene och familjen praktfjärilar. Inga underarter finns listade i Catalogue of Life.
Bildgalleri
Källor
Externa länkar
Praktfjärilar
ampedusa | swedish | 1.345218 |
ring_finger_not_move/NBK279362.txt | **Warning:** The NCBI web site requires JavaScript to function. [ more...
](/guide/browsers/#enablejs "Learn how to enable JavaScript")
An official website of the United States government
Here's how you know
**The .gov means it's official.**
Federal government websites often end in .gov or .mil. Before sharing
sensitive information, make sure you're on a federal government site.
**The site is secure.**
The **https://** ensures that you are connecting to the official website and
that any information you provide is encrypted and transmitted securely.
[ 
](/)
[ Log in ](https://account.ncbi.nlm.nih.gov) Show account info
Close
#### Account
Logged in as:
** username **
* [ Dashboard ](/myncbi/)
* [ Publications ](/myncbi/collections/bibliography/)
* [ Account settings ](/account/settings/)
* [ Log out ](/account/signout/)
[ Access keys ](https://www.ncbi.nlm.nih.gov/guide/browsers/#ncbi_accesskeys)
[ NCBI Homepage ](https://www.ncbi.nlm.nih.gov) [ MyNCBI Homepage ](/myncbi/)
Main Content Main Navigation
# [ Bookshelf ](/books/ "Bookshelf home")
##
Search database Books All Databases Assembly Biocollections BioProject
BioSample Books ClinVar Conserved Domains dbGaP dbVar Gene Genome GEO
DataSets GEO Profiles GTR Identical Protein Groups MedGen MeSH NLM
Catalog Nucleotide OMIM PMC PopSet Protein Protein Clusters Protein
Family Models PubChem BioAssay PubChem Compound PubChem Substance PubMed
SNP SRA Structure Taxonomy ToolKit ToolKitAll ToolKitBookgh
Search term
Search
* [ Browse Titles ](/books/browse/)
* [ Advanced ](/books/advanced/)
* [ Help ](/books/NBK3833/)
* [ Disclaimer ](https://www.ncbi.nlm.nih.gov/books/about/disclaimer/)
NCBI Bookshelf. A service of the National Library of Medicine, National
Institutes of Health.
InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and
Efficiency in Health Care (IQWiG); 2006-.
[  ](/books/n/pmh_iqwig/ "Table of Contents Page")
## InformedHealth.org [Internet].
Show details
Cologne, Germany: [ Institute for Quality and Efficiency in Health Care
(IQWiG) ](https://www.informedhealth.org/) ; 2006-.
* [ Contents ](/books/n/pmh_iqwig/)
Search term
[ < Prev ](/books/n/pmh_iqwig/i2221/ "Previous page in this title") [ Next >
](/books/n/pmh_iqwig/i2224/ "Next page in this title")
# In brief: How do hands work?
Last Update: May 20, 2021 ; Next update: 2024.
Hands have a very delicate and complex structure. This gives muscles and
joints in the hand a great range of movement and precision. The different
forces are also distributed in the best possible way. Thanks to this
structure, you can do a wide range of things with your hands, such as grip
objects tightly and lift heavy weights, as well as guide a fine thread through
the tiny eye of a needle.
Hands are also quite vulnerable, though: [ Tendons
](/books/n/pmh_iqwig/i3219/) , [ nerve fibers ](/books/n/pmh_iqwig/i2247/) ,
blood vessels and fairly thin bones are all positioned right under the [ skin
](/books/n/pmh_iqwig/i2101/) and are only protected by a thin layer of muscle
and fat. Only the palm is protected by a strong pad of tendons (aponeurosis),
enabling a powerful grip. Our hands are put through quite a lot every day, and
often come into contact with potentially harmful tools. As a result, hand
injuries and problems due to wear and tear are very common.
The right and left hand are each controlled by the opposite side of the [
brain ](/books/n/pmh_iqwig/i2143/) . Usually one hand is preferred for
carrying out fine and complex movements, so we often say people are either
right-handed or left-handed.
## Bones and joints
The human hand is made up of a total of 27 individual bones: 8 carpal bones
(in the base of the hand), 5 metacarpal bones (in the middle part of the hand)
and 14 phalanges (finger bones) are connected by [ joints
](/books/n/pmh_iqwig/i2224/) and [ ligaments ](/books/n/pmh_iqwig/i3218/) .
About one quarter of all our body’s bones are found in our hands. The hand can
be divided up into three different areas based on the joints:
* Carpus (wrist bones)
* Metacarpus
* Fingers
### Wrist
The wrist is made up of two parts of a joint that work as one functional unit.
It allows us to flex (bend) or extend (stretch) our hands. We can also tilt
our hands sideways, towards our little finger or thumb.
### Carpus
The eight carpal bones are held together tightly by ligaments, and are more or
less fixed in place. They are positioned in two rows of four carpal bones
each. Together with the radius bone in the forearm, two of the carpal bones
(the scaphoid bone and the lunate bone) form the lower part of the wrist
joint, which is very important for hand movements. The ulna bone in the
forearm is separated from the carpal bones by a cartilage disc. The other part
of the joint is located between the two rows of carpal bones.
### Metacarpus
After the second row of carpal bones comes the metacarpus. This middle part of
the hand consists of five long metacarpal bones. You can feel them quite
clearly on the back of your hand. One of the carpal bones and the long thumb
bone come together to form the basal joint of the thumb. Known as the
carpometacarpal joint, it enables the thumb to be particularly flexible.
### Fingers
The freely movable part of our hand is made up of five digits (four fingers
and one thumb). Each finger has three individual bones, and the thumb only has
two. The fingers have three joints each, which can only be bent and stretched
in one direction. The thumb is the only digit that can twist, thanks to the
saddle-shaped carpometacarpal joint.
## Muscles
There are over 30 muscles in the hand, working together in a highly complex
way. Movements of the hand are mostly started by muscles in the forearm. Only
the thin tendons of these muscles are found directly in the hand: the extensor
tendons used for stretching the hand run through the back of the hand to the
tips of the fingers, and the flexor (bending) tendons run through the palms to
the fingers.
### Short muscles of the hand
There are short muscles between the individual metacarpal bones of the hand.
They allow us to spread our fingers (abduction) and then pull them back
together (adduction). They also help to bend and stretch the fingers.
### The thenar eminence and the hypothenar eminence muscles
Two groups of more powerful muscles in the hand itself make up the thenar
eminence (at the base of the thumb) and the hypothenar eminence (controlling
the movement of the little finger). Among other things, the thenar muscles
enable the thumb and the tips of the four fingers to touch each other
(opposable thumb). A separate muscle (the adductor pollicis) is used to pull
the thumb towards the palm. The hypothenar eminence muscles are mainly used
for sticking out the little finger and pulling it inwards again, and for
tightening the skin that covers the hypothenar eminence.
### Lumbricals
The lumbricals of the hand are four thin, worm-like muscles that help bend the
metacarpophalangeal joints and extend the fingers.
## Connective tissue and tendons
Some parts of the long flexor and extensor tendons of the forearm muscles are
surrounded by protective layers called [ tendon sheaths
](/books/n/pmh_iqwig/i3213/) . Tendon sheaths contain a fluid that acts as a
lubricant. This allows the tendons to slide smoothly through the [ sheaths
](/books/n/pmh_iqwig/i3219/) , without friction.
Muscle tendons, nerves and blood vessels running from the forearm to the hand
pass through a tunnel-like passageway on the palm side of the wrist. Known as
the [ carpal tunnel ](/books/n/pmh_iqwig/i2708/) , this passageway is made up
of strong connective tissue and carpal bones.
The carpal tunnel (seen from the palm side of the hand)
## Function of the muscles: Power, touch and precision
Our hands can grasp and move objects in two different ways: with a power grip
or precision grip. The object's size, shape, weight and ease of handling
determines which of these two approaches is used. The power grip is better
suited for large, heavy objects, and the precision grip is used for small,
delicate objects.
### Power grip
The power grip is used to do things like carry heavy bags or hold on to a
handle. In the power grip, the object is held in the palm of the hand, and the
long flexor tendons pull the fingers and the thumb so that they can tightly
grasp the object. This grip is made possible by the four other fingers flexing
(bending) and, most importantly, the ability of the thumb to be positioned
opposite the fingers. With the hand in this position, larger objects such as a
stone or a heavy bottle can be held and moved in a controlled way. The heavier
the weight and the smoother the surface is, the more strength is needed to
hold and move the object.
### Precision grip
The precision grip is important for moving small and delicate objects, for
example when writing, sewing or drawing. When using the precision grip, the
thumb and the index (“pointer”) finger work like tweezers: The thumb is
opposite one or more fingertips, allowing the hand to grip even very small
objects – like pencils or delicate instruments – in a controlled way.
## Blood supply
The hand is supplied with [ blood ](/books/n/pmh_iqwig/i2249/) through two
main arteries: one on the same side as the thumb, and one on the same side as
the little finger. These two arteries each curve around in an arch shape where
the palm is, so that the hand is supplied with oxygen-rich blood through a
double loop. These loops have branches of blood vessels leading off into the
individual fingers. Each artery is accompanied by veins and nerves: In total,
each finger is supplied by four bundles of nerves and blood vessels.
Location of the main nerves and blood vessels in the hand
## Nerves
The muscles and skin of the hand are supplied by three [ nerves
](/books/n/pmh_iqwig/i2247/) :
* the radial nerve (nervus radialis),
* the median nerve (nervus medianus), and
* the ulnar nerve (nervus ulnaris).
The ulnar nerve moves the muscles of the hypothenar eminence, the muscles
between the bones of the metacarpus, the muscle that pulls the thumb inwards
(adductor pollicis) and two of the lumbrical muscles between fingers. This
nerve also picks up sensations from the area below the little finger and the
side of the ring finger closest to it.
The median nerve is responsible for the movement of the thenar eminence
muscles and the rest of the lumbricals. It is also responsible for the
perception of skin sensations on the palm, thumb, index finger, and middle
finger, as well as sensations on the side of the ring finger closest to the
middle finger.
The radial nerve activates the finger extensors and the muscles in the wrist
that are responsible for extending the hand. It also carries sensations from
the skin on the back of the hand and the back of the thumb to the brain.
## The sense of touch
The fingers on each hand are bent and stretched about 25 million times over
the course of a lifetime. Our hands also have very sensitive “antennae” for
receiving information from the environment: There are a total of 17,000 touch
receptors and free nerve endings in the palm. These pick up sensations of
pressure, movement and vibration. So it is with good reason that the sense of
touch is often associated with the hands. The skin on our fingertips is
especially sensitive to touch.
## Sources
* Brandes R, Lang F, Schmidt R (Ed). Physiologie des Menschen: mit Pathophysiologie. Berlin: Springer; 2019.
* Lippert H. Lehrbuch Anatomie. München: Urban und Fischer; 2003.
* Menche N (Ed). Biologie Anatomie Physiologie. München: Urban und Fischer; 2012.
* Pschyrembel. Klinisches Wörterbuch. Berlin: De Gruyter; 2017.
* IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.
Because IQWiG is a German institute, some of the information provided here is
specific to the German health care system. The suitability of any of the
described options in an individual case can be determined by talking to a
doctor. informedhealth.org can provide support for talks with doctors and
other medical professionals, but cannot replace them. We do not offer
individual consultations.
Our information is based on the results of good-quality studies. It is written
by a team of health care professionals, scientists and editors, and reviewed
by external experts. You can find a detailed description of how our health
information is produced and updated in our methods.
© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK279362
[ Contents ](/books/n/pmh_iqwig/)
[ < Prev ](/books/n/pmh_iqwig/i2221/ "Previous page in this title") [ Next >
](/books/n/pmh_iqwig/i2224/ "Next page in this title")
Share
### Views
* [ PubReader ](/books/NBK279362/?report=reader)
* [ Print View ](/books/NBK279362/?report=printable)
* Cite this Page
InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and
Efficiency in Health Care (IQWiG); 2006-. In brief: How do hands work?
[Updated 2021 May 20].
### In this Page
* Bones and joints
* Muscles
* Connective tissue and tendons
* Function of the muscles: Power, touch and precision
* Blood supply
* Nerves
* The sense of touch
* Sources
### Informed Health Links
* [ About ](https://www.informedhealth.org/informed-health.2169.en.html)
### Recent Activity
[ Clear ](javascript:historyDisplayState\('ClearHT'\)) [ Turn Off
](javascript:historyDisplayState\('HTOff'\)) [ Turn On
](javascript:historyDisplayState\('HTOn'\))
* [ In brief: How do hands work? - InformedHealth.org ](/portal/utils/pageresolver.fcgi?recordid=6630410612fea5609a8aebf1)
In brief: How do hands work? - InformedHealth.org
Your browsing activity is empty.
Activity recording is turned off.
[ Turn recording back on ](javascript:historyDisplayState\('HTOn'\))
[ See more... ](/sites/myncbi/recentactivity)
Follow NCBI
[ Twitter ](https://twitter.com/ncbi) [ Facebook
](https://www.facebook.com/ncbi.nlm) [ LinkedIn
](https://www.linkedin.com/company/ncbinlm) [ GitHub
](https://github.com/ncbi) [ NCBI Insights Blog
](https://ncbiinsights.ncbi.nlm.nih.gov/)
[ Connect with NLM ](https://www.nlm.nih.gov/socialmedia/index.html)
* [ Twitter ](https://twitter.com/NLM_NIH)
* [ Facebook ](https://www.facebook.com/nationallibraryofmedicine)
* [ Youtube ](https://www.youtube.com/user/NLMNIH)
National Library of Medicine
[ 8600 Rockville Pike
Bethesda, MD 20894
](https://www.google.com/maps/place/8600+Rockville+Pike,+Bethesda,+MD+20894/@38.9959508,-77.101021,17z/data=!3m1!4b1!4m5!3m4!1s0x89b7c95e25765ddb:0x19156f88b27635b8!8m2!3d38.9959508!4d-77.0988323)
[ Web Policies ](https://www.nlm.nih.gov/web_policies.html)
[ FOIA ](https://www.nih.gov/institutes-nih/nih-office-director/office-
communications-public-liaison/freedom-information-act-office)
[ HHS Vulnerability Disclosure ](https://www.hhs.gov/vulnerability-disclosure-
policy/index.html)
[ Help ](https://support.nlm.nih.gov/)
[ Accessibility ](https://www.nlm.nih.gov/accessibility.html)
[ Careers ](https://www.nlm.nih.gov/careers/careers.html)
* [ NLM ](//www.nlm.nih.gov/)
* [ NIH ](https://www.nih.gov/)
* [ HHS ](https://www.hhs.gov/)
* [ USA.gov ](https://www.usa.gov/)
| biology | 2115667 | https://sv.wikipedia.org/wiki/Ischnomesus%20norvegicus | Ischnomesus norvegicus | Ischnomesus norvegicus är en kräftdjursart som beskrevs av Jörundur Svavarsson 1984. Ischnomesus norvegicus ingår i släktet Ischnomesus och familjen Ischnomesidae. Inga underarter finns listade i Catalogue of Life.
Källor
Externa länkar
Gråsuggor och tånglöss
norvegicus | swedish | 1.207834 |
insects_attracted_to_light/Light.txt |
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).
In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum, and polarization. Its speed in vacuum, 299792458 m/s, is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and particles. The study of light, known as optics, is an important research area in modern physics.
The main source of natural light on Earth is the Sun. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight.
Electromagnetic spectrum and visible light
The electromagnetic spectrum, with the visible portion highlighted. The bottom graph (Visible spectrum) is wavelength in units of nanometres (nm).
Main article: Electromagnetic spectrum
Generally, electromagnetic radiation (EMR) is classified by wavelength into radio waves, microwaves, infrared, the visible spectrum that we perceive as light, ultraviolet, X-rays and gamma rays. The designation "radiation" excludes static electric, magnetic and near fields.
The behavior of EMR depends on its wavelength. Higher frequencies have shorter wavelengths and lower frequencies have longer wavelengths. When EMR interacts with single atoms and molecules, its behavior depends on the amount of energy per quantum it carries.
EMR in the visible light region consists of quanta (called photons) that are at the lower end of the energies that are capable of causing electronic excitation within molecules, which leads to changes in the bonding or chemistry of the molecule. At the lower end of the visible light spectrum, EMR becomes invisible to humans (infrared) because its photons no longer have enough individual energy to cause a lasting molecular change (a change in conformation) in the visual molecule retinal in the human retina, which change triggers the sensation of vision.
There exist animals that are sensitive to various types of infrared, but not by means of quantum-absorption. Infrared sensing in snakes depends on a kind of natural thermal imaging, in which tiny packets of cellular water are raised in temperature by the infrared radiation. EMR in this range causes molecular vibration and heating effects, which is how these animals detect it.
Above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nm and the internal lens below 400 nm. Furthermore, the rods and cones located in the retina of the human eye cannot detect the very short (below 360 nm) ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses (such as insects and shrimp) are able to detect ultraviolet, by quantum photon-absorption mechanisms, in much the same chemical way that humans detect visible light.
Various sources define visible light as narrowly as 420–680 nm to as broadly as 380–800 nm. Under ideal laboratory conditions, people can see infrared up to at least 1,050 nm; children and young adults may perceive ultraviolet wavelengths down to about 310–313 nm.
Plant growth is also affected by the colour spectrum of light, a process known as photomorphogenesis.
Speed of light
Main article: Speed of light
Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily
The speed of light in vacuum is defined to be exactly 299 792 458 m/s (approx. 186,282 miles per second). The fixed value of the speed of light in SI units results from the fact that the metre is now defined in terms of the speed of light. All forms of electromagnetic radiation move at exactly this same speed in vacuum.
Different physicists have attempted to measure the speed of light throughout history. Galileo attempted to measure the speed of light in the seventeenth century. An early experiment to measure the speed of light was conducted by Ole Rømer, a Danish physicist, in 1676. Using a telescope, Rømer observed the motions of Jupiter and one of its moons, Io. Noting discrepancies in the apparent period of Io's orbit, he calculated that light takes about 22 minutes to traverse the diameter of Earth's orbit. However, its size was not known at that time. If Rømer had known the diameter of the Earth's orbit, he would have calculated a speed of 227000000 m/s.
Another more accurate measurement of the speed of light was performed in Europe by Hippolyte Fizeau in 1849. Fizeau directed a beam of light at a mirror several kilometers away. A rotating cog wheel was placed in the path of the light beam as it traveled from the source, to the mirror and then returned to its origin. Fizeau found that at a certain rate of rotation, the beam would pass through one gap in the wheel on the way out and the next gap on the way back. Knowing the distance to the mirror, the number of teeth on the wheel and the rate of rotation, Fizeau was able to calculate the speed of light as 313000000 m/s.
Léon Foucault carried out an experiment which used rotating mirrors to obtain a value of 298 000 000 m/s in 1862. Albert A. Michelson conducted experiments on the speed of light from 1877 until his death in 1931. He refined Foucault's methods in 1926 using improved rotating mirrors to measure the time it took light to make a round trip from Mount Wilson to Mount San Antonio in California. The precise measurements yielded a speed of 299 796 000 m/s.
The effective velocity of light in various transparent substances containing ordinary matter, is less than in vacuum. For example, the speed of light in water is about 3/4 of that in vacuum.
Two independent teams of physicists were said to bring light to a "complete standstill" by passing it through a Bose–Einstein condensate of the element rubidium, one team at Harvard University and the Rowland Institute for Science in Cambridge, Massachusetts and the other at the Harvard–Smithsonian Center for Astrophysics, also in Cambridge. However, the popular description of light being "stopped" in these experiments refers only to light being stored in the excited states of atoms, then re-emitted at an arbitrary later time, as stimulated by a second laser pulse. During the time it had "stopped", it had ceased to be light.
Optics
Main article: Optics
The study of light and the interaction of light and matter is termed optics. The observation and study of optical phenomena such as rainbows and the aurora borealis offer many clues as to the nature of light.
A transparent object allows light to transmit or pass through. Conversely, an opaque object does not allow light to transmit through and instead reflecting or absorbing the light it receives. Most objects do not reflect or transmit light specularly and to some degree scatters the incoming light, which is called glossiness. Surface scatterance is caused by the surface roughness of the reflecting surfaces, and internal scatterance is caused by the difference of refractive index between the particles and medium inside the object. Like transparent objects, translucent objects allow light to transmit through, but translucent objects also scatter certain wavelength of light via internal scatterance.
Refraction
Main article: Refraction
Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.
Refraction is the bending of light rays when passing through a surface between one transparent material and another. It is described by Snell's Law:
n
1
sin
θ
1
=
n
2
sin
θ
2
.
{\displaystyle n_{1}\sin \theta _{1}=n_{2}\sin \theta _{2}\ .}
where θ1 is the angle between the ray and the surface normal in the first medium, θ2 is the angle between the ray and the surface normal in the second medium and n1 and n2 are the indices of refraction, n = 1 in a vacuum and n > 1 in a transparent substance.
When a beam of light crosses the boundary between a vacuum and another medium, or between two different media, the wavelength of the light changes, but the frequency remains constant. If the beam of light is not orthogonal (or rather normal) to the boundary, the change in wavelength results in a change in the direction of the beam. This change of direction is known as refraction.
The refractive quality of lenses is frequently used to manipulate light in order to change the apparent size of images. Magnifying glasses, spectacles, contact lenses, microscopes and refracting telescopes are all examples of this manipulation.
Light sources
"Lightsource" redirects here. For the solar energy developer named Lightsource, see Lightsource Renewable Energy. For a particle accelerator used to generate X-rays, see Synchrotron light source.
Further information: List of light sources
There are many sources of light. A body at a given temperature emits a characteristic spectrum of black-body radiation. A simple thermal source is sunlight, the radiation emitted by the chromosphere of the Sun at around 6,000 K (5,730 °C; 10,340 °F). Solar radiation peaks in the visible region of the electromagnetic spectrum when plotted in wavelength units, and roughly 44% of the radiation that reaches the ground is visible. Another example is incandescent light bulbs, which emit only around 10% of their energy as visible light and the remainder as infrared. A common thermal light source in history is the glowing solid particles in flames, but these also emit most of their radiation in the infrared and only a fraction in the visible spectrum.
The peak of the black-body spectrum is in the deep infrared, at about 10 micrometre wavelength, for relatively cool objects like human beings. As the temperature increases, the peak shifts to shorter wavelengths, producing first a red glow, then a white one and finally a blue-white colour as the peak moves out of the visible part of the spectrum and into the ultraviolet. These colours can be seen when metal is heated to "red hot" or "white hot". Blue-white thermal emission is not often seen, except in stars (the commonly seen pure-blue colour in a gas flame or a welder's torch is in fact due to molecular emission, notably by CH radicals emitting a wavelength band around 425 nm and is not seen in stars or pure thermal radiation).
Atoms emit and absorb light at characteristic energies. This produces "emission lines" in the spectrum of each atom. Emission can be spontaneous, as in light-emitting diodes, gas discharge lamps (such as neon lamps and neon signs, mercury-vapor lamps, etc.) and flames (light from the hot gas itself—so, for example, sodium in a gas flame emits characteristic yellow light). Emission can also be stimulated, as in a laser or a microwave maser.
Deceleration of a free charged particle, such as an electron, can produce visible radiation: cyclotron radiation, synchrotron radiation and bremsstrahlung radiation are all examples of this. Particles moving through a medium faster than the speed of light in that medium can produce visible Cherenkov radiation. Certain chemicals produce visible radiation by chemoluminescence. In living things, this process is called bioluminescence. For example, fireflies produce light by this means and boats moving through water can disturb plankton which produce a glowing wake.
Certain substances produce light when they are illuminated by more energetic radiation, a process known as fluorescence. Some substances emit light slowly after excitation by more energetic radiation. This is known as phosphorescence. Phosphorescent materials can also be excited by bombarding them with subatomic particles. Cathodoluminescence is one example. This mechanism is used in cathode-ray tube television sets and computer monitors.
Hong Kong illuminated by colourful artificial lighting
Certain other mechanisms can produce light:
Bioluminescence
Cherenkov radiation
Electroluminescence
Scintillation
Sonoluminescence
Triboluminescence
When the concept of light is intended to include very-high-energy photons (gamma rays), additional generation mechanisms include:
Particle–antiparticle annihilation
Radioactive decay
Measurement
Main articles: Photometry (optics) and Radiometry
Light is measured with two main alternative sets of units: radiometry consists of measurements of light power at all wavelengths, while photometry measures light with wavelength weighted with respect to a standardized model of human brightness perception. Photometry is useful, for example, to quantify Illumination (lighting) intended for human use.
The photometry units are different from most systems of physical units in that they take into account how the human eye responds to light. The cone cells in the human eye are of three types which respond differently across the visible spectrum and the cumulative response peaks at a wavelength of around 555 nm. Therefore, two sources of light which produce the same intensity (W/m) of visible light do not necessarily appear equally bright. The photometry units are designed to take this into account and therefore are a better representation of how "bright" a light appears to be than raw intensity. They relate to raw power by a quantity called luminous efficacy and are used for purposes like determining how to best achieve sufficient illumination for various tasks in indoor and outdoor settings. The illumination measured by a photocell sensor does not necessarily correspond to what is perceived by the human eye and without filters which may be costly, photocells and charge-coupled devices (CCD) tend to respond to some infrared, ultraviolet or both.
Light pressure
Main article: Radiation pressure
Light exerts physical pressure on objects in its path, a phenomenon which can be deduced by Maxwell's equations, but can be more easily explained by the particle nature of light: photons strike and transfer their momentum. Light pressure is equal to the power of the light beam divided by c, the speed of light. Due to the magnitude of c, the effect of light pressure is negligible for everyday objects. For example, a one-milliwatt laser pointer exerts a force of about 3.3 piconewtons on the object being illuminated; thus, one could lift a U.S. penny with laser pointers, but doing so would require about 30 billion 1-mW laser pointers. However, in nanometre-scale applications such as nanoelectromechanical systems (NEMS), the effect of light pressure is more significant and exploiting light pressure to drive NEMS mechanisms and to flip nanometre-scale physical switches in integrated circuits is an active area of research. At larger scales, light pressure can cause asteroids to spin faster, acting on their irregular shapes as on the vanes of a windmill. The possibility of making solar sails that would accelerate spaceships in space is also under investigation.
Although the motion of the Crookes radiometer was originally attributed to light pressure, this interpretation is incorrect; the characteristic Crookes rotation is the result of a partial vacuum. This should not be confused with the Nichols radiometer, in which the (slight) motion caused by torque (though not enough for full rotation against friction) is directly caused by light pressure.
As a consequence of light pressure, Einstein in 1909 predicted the existence of "radiation friction" which would oppose the movement of matter. He wrote, "radiation will exert pressure on both sides of the plate. The forces of pressure exerted on the two sides are equal if the plate is at rest. However, if it is in motion, more radiation will be reflected on the surface that is ahead during the motion (front surface) than on the back surface. The backwardacting force of pressure exerted on the front surface is thus larger than the force of pressure acting on the back. Hence, as the resultant of the two forces, there remains a force that counteracts the motion of the plate and that increases with the velocity of the plate. We will call this resultant 'radiation friction' in brief."
Usually light momentum is aligned with its direction of motion. However, for example in evanescent waves momentum is transverse to direction of propagation.
Historical theories about light, in chronological order
Classical Greece and Hellenism
In the fifth century BC, Empedocles postulated that everything was composed of four elements; fire, air, earth and water. He believed that Aphrodite made the human eye out of the four elements and that she lit the fire in the eye which shone out from the eye making sight possible. If this were true, then one could see during the night just as well as during the day, so Empedocles postulated an interaction between rays from the eyes and rays from a source such as the sun.
In about 300 BC, Euclid wrote Optica, in which he studied the properties of light. Euclid postulated that light travelled in straight lines and he described the laws of reflection and studied them mathematically. He questioned that sight is the result of a beam from the eye, for he asks how one sees the stars immediately, if one closes one's eyes, then opens them at night. If the beam from the eye travels infinitely fast this is not a problem.
In 55 BC, Lucretius, a Roman who carried on the ideas of earlier Greek atomists, wrote that "The light & heat of the sun; these are composed of minute atoms which, when they are shoved off, lose no time in shooting right across the interspace of air in the direction imparted by the shove." (from On the nature of the Universe). Despite being similar to later particle theories, Lucretius's views were not generally accepted. Ptolemy (c. second century) wrote about the refraction of light in his book Optics.
Classical India
In ancient India, the Hindu schools of Samkhya and Vaisheshika, from around the early centuries AD developed theories on light. According to the Samkhya school, light is one of the five fundamental "subtle" elements (tanmatra) out of which emerge the gross elements. The atomicity of these elements is not specifically mentioned and it appears that they were actually taken to be continuous.
The Vishnu Purana refers to sunlight as "the seven rays of the sun".
The Indian Buddhists, such as Dignāga in the fifth century and Dharmakirti in the seventh century, developed a type of atomism that is a philosophy about reality being composed of atomic entities that are momentary flashes of light or energy. They viewed light as being an atomic entity equivalent to energy.
Descartes
René Descartes (1596–1650) held that light was a mechanical property of the luminous body, rejecting the "forms" of Ibn al-Haytham and Witelo as well as the "species" of Bacon, Grosseteste and Kepler. In 1637 he published a theory of the refraction of light that assumed, incorrectly, that light travelled faster in a denser medium than in a less dense medium. Descartes arrived at this conclusion by analogy with the behaviour of sound waves. Although Descartes was incorrect about the relative speeds, he was correct in assuming that light behaved like a wave and in concluding that refraction could be explained by the speed of light in different media.
Descartes is not the first to use the mechanical analogies but because he clearly asserts that light is only a mechanical property of the luminous body and the transmitting medium, Descartes's theory of light is regarded as the start of modern physical optics.
Particle theory
Main article: Corpuscular theory of light
Pierre Gassendi
Pierre Gassendi (1592–1655), an atomist, proposed a particle theory of light which was published posthumously in the 1660s. Isaac Newton studied Gassendi's work at an early age and preferred his view to Descartes's theory of the plenum. He stated in his Hypothesis of Light of 1675 that light was composed of corpuscles (particles of matter) which were emitted in all directions from a source. One of Newton's arguments against the wave nature of light was that waves were known to bend around obstacles, while light travelled only in straight lines. He did, however, explain the phenomenon of the diffraction of light (which had been observed by Francesco Grimaldi) by allowing that a light particle could create a localised wave in the aether.
Newton's theory could be used to predict the reflection of light, but could only explain refraction by incorrectly assuming that light accelerated upon entering a denser medium because the gravitational pull was greater. Newton published the final version of his theory in his Opticks of 1704. His reputation helped the particle theory of light to hold sway during the eighteenth century. The particle theory of light led Laplace to argue that a body could be so massive that light could not escape from it. In other words, it would become what is now called a black hole. Laplace withdrew his suggestion later, after a wave theory of light became firmly established as the model for light (as has been explained, neither a particle or wave theory is fully correct). A translation of Newton's essay on light appears in The large scale structure of space-time, by Stephen Hawking and George F. R. Ellis.
The fact that light could be polarized was for the first time qualitatively explained by Newton using the particle theory. Étienne-Louis Malus in 1810 created a mathematical particle theory of polarization. Jean-Baptiste Biot in 1812 showed that this theory explained all known phenomena of light polarization. At that time the polarization was considered as the proof of the particle theory.
Wave theory
To explain the origin of colours, Robert Hooke (1635–1703) developed a "pulse theory" and compared the spreading of light to that of waves in water in his 1665 work Micrographia ("Observation IX"). In 1672 Hooke suggested that light's vibrations could be perpendicular to the direction of propagation. Christiaan Huygens (1629–1695) worked out a mathematical wave theory of light in 1678 and published it in his Treatise on Light in 1690. He proposed that light was emitted in all directions as a series of waves in a medium called the luminiferous aether. As waves are not affected by gravity, it was assumed that they slowed down upon entering a denser medium.
Christiaan Huygens
Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.
The wave theory predicted that light waves could interfere with each other like sound waves (as noted around 1800 by Thomas Young). Young showed by means of a diffraction experiment that light behaved as waves. He also proposed that different colours were caused by different wavelengths of light and explained colour vision in terms of three-coloured receptors in the eye. Another supporter of the wave theory was Leonhard Euler. He argued in Nova theoria lucis et colorum (1746) that diffraction could more easily be explained by a wave theory. In 1816 André-Marie Ampère gave Augustin-Jean Fresnel an idea that the polarization of light can be explained by the wave theory if light were a transverse wave.
Later, Fresnel independently worked out his own wave theory of light and presented it to the Académie des Sciences in 1817. Siméon Denis Poisson added to Fresnel's mathematical work to produce a convincing argument in favor of the wave theory, helping to overturn Newton's corpuscular theory. By the year 1821, Fresnel was able to show via mathematical methods that polarization could be explained by the wave theory of light if and only if light was entirely transverse, with no longitudinal vibration whatsoever.
The weakness of the wave theory was that light waves, like sound waves, would need a medium for transmission. The existence of the hypothetical substance luminiferous aether proposed by Huygens in 1678 was cast into strong doubt in the late nineteenth century by the Michelson–Morley experiment.
Newton's corpuscular theory implied that light would travel faster in a denser medium, while the wave theory of Huygens and others implied the opposite. At that time, the speed of light could not be measured accurately enough to decide which theory was correct. The first to make a sufficiently accurate measurement was Léon Foucault, in 1850. His result supported the wave theory and the classical particle theory was finally abandoned, only to partly re-emerge in the twentieth century.
Electromagnetic theory
Main article: Electromagnetic radiation
A linearly polarized electromagnetic wave traveling along the z-axis, with E denoting the electric field and perpendicular B denoting magnetic field
In 1845, Michael Faraday discovered that the plane of polarization of linearly polarized light is rotated when the light rays travel along the magnetic field direction in the presence of a transparent dielectric, an effect now known as Faraday rotation. This was the first evidence that light was related to electromagnetism. In 1846 he speculated that light might be some form of disturbance propagating along magnetic field lines. Faraday proposed in 1847 that light was a high-frequency electromagnetic vibration, which could propagate even in the absence of a medium such as the ether.
Faraday's work inspired James Clerk Maxwell to study electromagnetic radiation and light. Maxwell discovered that self-propagating electromagnetic waves would travel through space at a constant speed, which happened to be equal to the previously measured speed of light. From this, Maxwell concluded that light was a form of electromagnetic radiation: he first stated this result in 1862 in On Physical Lines of Force. In 1873, he published A Treatise on Electricity and Magnetism, which contained a full mathematical description of the behavior of electric and magnetic fields, still known as Maxwell's equations. Soon after, Heinrich Hertz confirmed Maxwell's theory experimentally by generating and detecting radio waves in the laboratory and demonstrating that these waves behaved exactly like visible light, exhibiting properties such as reflection, refraction, diffraction and interference. Maxwell's theory and Hertz's experiments led directly to the development of modern radio, radar, television, electromagnetic imaging and wireless communications.
In the quantum theory, photons are seen as wave packets of the waves described in the classical theory of Maxwell. The quantum theory was needed to explain effects even with visual light that Maxwell's classical theory could not (such as spectral lines).
Quantum theory
In 1900 Max Planck, attempting to explain black-body radiation, suggested that although light was a wave, these waves could gain or lose energy only in finite amounts related to their frequency. Planck called these "lumps" of light energy "quanta" (from a Latin word for "how much"). In 1905, Albert Einstein used the idea of light quanta to explain the photoelectric effect and suggested that these light quanta had a "real" existence. In 1923 Arthur Holly Compton showed that the wavelength shift seen when low intensity X-rays scattered from electrons (so called Compton scattering) could be explained by a particle-theory of X-rays, but not a wave theory. In 1926 Gilbert N. Lewis named these light quanta particles photons.
Eventually the modern theory of quantum mechanics came to picture light as (in some sense) both a particle and a wave and (in another sense), as a phenomenon which is neither a particle nor a wave (which actually are macroscopic phenomena, such as baseballs or ocean waves). Instead, modern physics sees light as something that can be described sometimes with mathematics appropriate to one type of macroscopic metaphor (particles) and sometimes another macroscopic metaphor (water waves), but is actually something that cannot be fully imagined. As in the case for radio waves and the X-rays involved in Compton scattering, physicists have noted that electromagnetic radiation tends to behave more like a classical wave at lower frequencies, but more like a classical particle at higher frequencies, but never completely loses all qualities of one or the other. Visible light, which occupies a middle ground in frequency, can easily be shown in experiments to be describable using either a wave or particle model, or sometimes both.
In February 2018, scientists reported, for the first time, the discovery of a new form of light, which may involve polaritons, that could be useful in the development of quantum computers.
Use for light on Earth
Sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the energy used by living things. Some species of animals generate their own light, a process called bioluminescence. For example, fireflies use light to locate mates and vampire squid use it to hide themselves from prey.
See also
Physics portalScience portal
Automotive lighting
Ballistic photon
Colour temperature
Fermat's principle
Huygens' principle
Journal of Luminescence
Light art
Light beam – in particular about light beams visible from the side
Light Fantastic (TV series)
Light mill
Light painting
Light pollution
Light therapy
Lighting
List of light sources
Luminescence: The Journal of Biological and Chemical Luminescence
Photic sneeze reflex
Right to light
Risks and benefits of sun exposure
Spectroscopy
Notes
| biology | 19358 | https://da.wikipedia.org/wiki/Foton | Foton | Fotonen er den elementarpartikel, der er ansvarlig for elektromagnetiske fænomener, eksempelvis elektromagnetisk stråling som røntgenstråling, ultraviolet lys, synligt lys, infrarødt lys, mikrobølger og radiobølger.
Fotonen adskiller sig fra andre elementarpartikler, f.eks. elektroner eller kvarker, ved at den ikke besidder nogen hvilemasse. I vakuum bevæger den sig med lysets hastighed, c = 299.792.458 m/s eller tæt på 300.000 km/s.
Som alle kvanter besidder fotonen både bølge- og partikelegenskaber (Partikel-bølge dualitet). Bølgeegenskaberne inkluderer brydning i linser og interferens. At fotonen også besidder partikelegenskaber kommer til udtryk ved, at den kun kan vekselvirke med stof ved at overføre en kvantiseret mængde energi givet ved
hvor h er Plancks konstant og er fotonernes bølgelængde. I modsætning hertil kan en almindelig bølge overføre eller modtage vilkårlige mængder af energi.
For synligt lys er en enkelt fotons energi mellem 2,8 × 10-19 og 5 × 10-19 J eller 1,8 og 3,1 eV, en relativt lille energi, men nok til at excitere et enkelt molekyle i øjets fotoreceptorer og dermed bidrage til synssansen. Til sammenligning skal anføres at fotonenergien af UV-stråling er mellem 3.10 og 12.4 eV, tilstrækkeligt til at bryde en kemisk binding og danne radikaler.
Udover at have en energi har fotoner også en impuls og en polarisering. Eftersom fotonen følger kvantemekanikkens love, er det ofte tilfældet, at dens egenskaber ikke har veldefinerede værdier. Derimod er de beskrevet ved en sandsynlighed for at måle en bestemt polarisering, position eller impuls. Selvom en foton er i stand til at excitere et enkelt molekyle, er det f.eks. ofte ikke muligt på forhånd at bestemme hvilket molekyle, der bliver exciteret.
Fysikere benytter ofte beskrivelsen af en foton, som en partikel der bærer elektromagnetisk stråling. Indenfor teoretisk fysik kan fotonen dog også betragtes som formidler af enhver type elektromagnetisk vekselvirkning, eksempelvis magnetfelter og elektrisk frastødning/tiltrækning mellem elektrisk ladede partikler.
Fotonen som koncept, blev udviklet gradvis omkring årene 1905-1907 af Albert Einstein for at forklare eksperimentelle observationer, der ikke stemte overens med den klassiske bølgebeskrivelse af lys. Specifikt forklarede foton-modellen lysets energis afhængighed af frekvens, samt at stof og stråling kan være i termisk ligevægt. Andre fysikere forsøgte at forklare disse observationer med semiklassiske modeller, hvor lys stadig blev beskrevet ved Maxwells ligninger, men hvor de materialer der udsendte og absorberede lyset var kvantiserede. Disse modeller medvirkede til udvikling af kvantemekanikken, men yderligere forsøg underbyggede Einsteins hypotese om at lyset er kvantiseret. Lyskvanterne er fotoner.
Fotonkonceptet har ført til store fremskridt i både eksperimentel og teoretisk fysik, f.eks. lasere, Bose-Einstein-kondensat og kvantefeltteori. Ifølge standardmodellen for partikelfysik, ligger fotoner til grund for alle elektriske og magnetiske felter og er selv et produkt af kravet om, at de fysiske love har visse symmetrier for ethvert punkt i rumtiden. Fotonens indbyggede egenskaber, som f.eks ladning, spin og (fravær af) masse, er bestemt ud fra disse symmetrier.
I 2007 lykkedes det at fastholde og måle tilstedeværelsen af en mikrobølgefoton i op til et halvt sekund mellem to superledende spejle.
Se også
Elementarpartikel
Kvantemekanik
Fotonisk krystal
Orbitalt impulsmoment (bølge)
Ultraviolet lys
Referencer
Eksterne henvisninger
Webarchive backup: En lyspartikel med identitetsproblemer (humoristisk tegning)
Number 523 #2, February 1, 2001, AIP: How Light Gets Through Tiny Holes Citat: "...Now, two research collaborations independently explain the results by showing that plasmons (themselves collective objects) and the photons of light form a composite object, known as a "surface plasmon polariton."..."
'Energy-sucking' Radio Antennas, N. Tesla's Power Receiver Citat: "...The truth is quite strange...By manipulating the EM fields, we can force an electrically-small receiving antenna to behave as if it was very, VERY large...In theory a tiny loop antenna can work as well as a longwire 1/2-wave antenna which is 10KM long...The energy doesn't vanish, instead it ends up INSIDE the atom. By resonantly creating an "anti-wave", the tiny atom has "sucked energy" out of the enormously long light waves as they go by...When all is said and done, our oscillating coil has absorbed half of the incoming EM energy and re-emitted (or "scattered") the rest..."
C. F. Bohren, "How can a particle absorb more than the light incident on it?", Am J Phys, 51 #4, pp323 Apr 1983 Citat: "...A particle can indeed absorb more than the light incident on it...In the former, strong absorption is associated with excitation of surfaces plasmons; in the latter it is associated with excitation of surface phonons. In both instances, the target area a particle presents to incident light can be much greater than its geometrical cross-sectional area...."
Regeneration revisited. The Tesla Connection by Gary L. Peterson Citat: "...So it may be said that Tesla anticipated the technique of regenerative feedback to increase detector sensitivity...A detailed description of how the negative resistance, negative inductance circuit works, including a differential form of the active antenna circuit and other pertinent information, can be found in U.S. Patent No. 5,296,866, Mar. 22, 199..."
Gaugebosoner
Kvantemekanik
Kvanteelektrodynamik | danish | 0.752863 |
insects_attracted_to_light/Proximate_and_ultimate_causation.txt | A proximate cause is an event which is closest to, or immediately responsible for causing, some observed result. This exists in contrast to a higher-level ultimate cause (or distal cause) which is usually thought of as the "real" reason something occurred.
The concept is used in many fields of research and analysis, including data science and ethology.
In most situations, an ultimate cause may itself be a proximate cause in comparison to a further ultimate cause. Hence we can continue the above example as follows:
In biology[edit]
Ultimate causation explains traits in terms of evolutionary forces acting on them.
Example: female animals often display preferences among male display traits, such as song. An ultimate explanation based on sexual selection states that females who display preferences have more vigorous or more attractive male offspring.
Proximate causation explains biological function in terms of immediate physiological or environmental factors.
Example: a female animal chooses to mate with a particular male during a mate choice trial. A possible proximate explanation states that one male produced a more intense signal, leading to elevated hormone levels in the female producing copulatory behaviour.
Although the behavior in these two examples is the same, the explanations are based on different sets of factors incorporating evolutionary versus physiological factors.
These can be further divided, for example proximate causes may be given in terms of local muscle movements or in terms of developmental biology (see Tinbergen's four questions).
In philosophy[edit]
In analytic philosophy, notions of cause adequacy are employed in the causal model. In order to explain the genuine cause of an effect, one would have to satisfy adequacy conditions, which include, among others, the ability to distinguish between:
Genuine causal relationships and accidents.
Causes and effects.
Causes and effects from a common cause.
One famous example of the importance of this is the Duhem–Quine thesis, which demonstrates that it is impossible to test a hypothesis in isolation, because an empirical test of the hypothesis requires one or more background assumptions. One way to solve this issue is to employ contrastive explanations. Several philosophers of science, such as Lipton, argue that contrastive explanations are able to detect genuine causes. An example of a contrastive explanation is a cohort study that includes a control group, where one can determine the cause from observing two otherwise identical samples. This view also circumvents the problem of infinite regression of "why" questions that proximate causes create.
In sociology[edit]
Sociologists use the related pair of terms "proximal causation" and "distal causation".
Proximal causation: explanation of human social behaviour by considering the immediate factors, such as symbolic interaction, understanding (Verstehen), and individual milieu that influence that behaviour. Most sociologists recognize that proximal causality is the first type of power humans experience; however, while factors such as family relationships may initially be meaningful, they are not as permanent, underlying, or determining as other factors such as institutions and social networks (Naiman 2008: 5).
Distal causation: explanation of human social behaviour by considering the larger context in which individuals carry out their actions. Proponents of the distal view of power argue that power operates at a more abstract level in the society as a whole (e.g. between economic classes) and that "all of us are affected by both types of power throughout our lives" (ibid). Thus, while individuals occupy roles and statuses relative to each other, it is the social structure and institutions in which these exist that are the ultimate cause of behaviour. A human biography can only be told in relation to the social structure, yet it also must be told in relation to unique individual experiences in order to reveal the complete picture (Mills 1959).
See also[edit]
Abductive reasoning
Causality
Causal model
Cause/Manner of death
Five whys
Four causes
Occam's razor
Pathology
Teleology | biology | 215048 | https://sv.wikipedia.org/wiki/Evolutionspsykologi | Evolutionspsykologi | Evolutionär psykologi eller evolutionspsykologi är ett teoretiskt perspektiv inom psykologin som tittar på kognition och beteende ur ett modernt evolutionärt perspektiv. Målet är att identifiera mänskliga psykologiska adaptioner som utvecklades för att hantera specifika problem som våra förfäder ställdes inför under evolutionen. Inom ramverket är psykologiska egenskaper och mekanismer antagligen funktionella produkter av det naturliga och sexuella urvalet, biprodukter som följde med funktionella adaptioner, eller ”noise” (till exempel slumpmässiga mutationer eller extrema miljöförändringar med mera, som påverkat den evolutionära processen).
Ett adaptionistiskt tänkande är vanligt inom evolutionär biologi när man tittar på fysiologiska mekanismer, så som till exempel hjärtat, lungorna och levern. Evolutionärpsykologer applicerar samma sätt att tänka men för psykologi, de argumenterar för att på samma sätt som hjärtat utvecklades för att pumpa blod, och levern för att avgifta kroppen, så finns det en modularitet i vårt sinne där olika psykologiska mekanismer utvecklades för att hantera olika adaptiva problem. Evolutionärpsykologer anser att mycket av det mänskliga beteendet helt enkelt är en output av psykologiska adaptioner som utvecklades för att hantera specifika problem i människans uråldriga miljö. Till exempel rovdjur, att få tag på föda, att undvika sjukdomar, konkurrens inom gruppen, konkurrens mellan grupper, föräldraskap.
En del evolutionärpsykologer argumenterar för att evolutionsteorin kan bidra till ett fundamentalt, metateoretiskt ramverk som integrerar all annan psykologi på samma sätt som evolutionär biologi utgör en ram för all biologi.
Evolutionärpsykologer anser att ett beteende eller en egenskap som existerar universellt för alla människor oavsett kultur, är goda kandidater för att vara evolutionära adaptioner. Detta inkluderar förmågan att förstå andras känslor, att skilja släktingar från icke släktingar, att identifiera och attraheras av hälsosammare partners och att samarbeta med andra. Forskningsresultat rörande mänskligt socialt beteende visar universalitet relaterat till barnadråp, intelligens, äktenskapstendenser, promiskuitet, uppfattning angående attraktivitet och föräldrainvestering i avkomma. Teorierna och empirin från evolutionär psykologi har tvärvetenskapligt applicerats på flera håll inom akademin, till exempel inom ekonomi, miljöpolitik, juridik, management, psykiatri, politik och litteratur.
Omfattning
Grundläggande principer
Evolutionär psykologi är ett tillvägagångssätt som ser den mänskliga naturen som en produkt av en universell uppsättning utvecklade psykologiska anpassningar till återkommande problem våra förfäders miljö. Förespråkare föreslår att evolutionspsykologin försöker integrera psykologin i resten av naturvetenskapen, förankra den i den organiserande biologiska teorin (evolutionsteorin), och därmed förstå psykologi som en gren av biologin. Antropologen John Tooby och psykologen Leda Cosmides säger:
”Evolutionary psychology is the long-forestalled scientific attempt to assemble out of the disjointed, fragmentary, and mutually contradictory human disciplines a single, logically integrated research framework for the psychological, social, and behavioral sciences – a framework that not only incorporates the evolutionary sciences on a full and equal basis, but that systematically works out all of the revisions in existing belief and research practice that such a synthesis requires.”
Precis som mänsklig fysiologi och evolutionär fysiologi har arbetat för att identifiera fysiska anpassningar av kroppen som representerar "mänsklig fysiologisk natur", så är syftet med evolutionär psykologi att identifiera utvecklade emotionella och kognitiva anpassningar som representerar "mänsklig psykologisk natur". Steven Pinker säger att evolutionärpsykologin "inte en enda teori utan en stor uppsättning hypoteser" och han säger även att evolutionärpsykologin har kommit att hänvisa till ett speciellt sätt att tillämpa evolutionsteori på sinnet, med tonvikt på anpassning, selektion på gennivå och modularitet. Evolutionspsykologi antar en förståelse av sinnet som är baserad på ”the computational theory of mind”. Den beskriver mentala processer som beräkningsoperationer, så att till exempel en rädslereaktion beskrivs som härrörande från en neurologisk beräkning som matar in perceptionsdata, t.ex. en visuell bild av en spindel, och matar ut lämplig reaktion, t.ex. rädsla för möjligen farlig djur. Enligt detta synsätt är all domängenerell inlärning omöjlig på grund av den kombinatoriska explosionen (the combinatorial explosion). Evolutionspsykologi specificerar domänen som problemet med överlevnad och reproduktion.
Medan filosofer i allmänhet har ansett att det mänskliga sinnet inkluderar breda förmågor, såsom förnuft och lust, beskriver evolutionära psykologer utvecklade psykologiska mekanismer som snävt fokuserade för att hantera specifika frågor, som att upptäcka free-riders eller välja partners. Disciplinen ser den mänskliga hjärnan som omfattande många funktionella mekanismer som kallas psykologiska adaptioner eller utvecklade kognitiva mekanismer/ kognitiva moduler, designade genom det naturligt urvalet. Exempel inkluderar språkinlärningsmoduler, mekanismer för att undvika incest, mekanismer för upptäckt av free-riders, intelligens och könsspecifika parningspreferenser, att få tag på föda, mekanism för att spåra ingruppsmedlemmar, agentdetekteringsmekanismer med fler. Vissa mekanismer, benämnda domänspecifika, hanterar återkommande adaptiva problem under loppet av människans evolutionära historia. Domängenerella mekanismer, å andra sidan, föreslås för att hantera nya uppkomna evolutionära problem.
Evolutionspsykologi har sina rötter i kognitiv psykologi och evolutionär biologi men bygger också på beteendeekologi, artificiell intelligens, genetik, etologi, antropologi, arkeologi, biologi och zoologi. Det är nära kopplat till sociobiologi, men det finns viktiga skillnader mellan dem, inklusive betoningen på domänspecifika snarare än domängenerella mekanismer, relevansen av mätningar av aktuell ”fitness”, vikten av missmatchningsteori och psykologi snarare än beteende.
Nikolaas Tinbergens fyra frågekategorier kan bidra till att tydliggöra skillnaderna mellan flera olika, men kompletterande, typer av förklaringar. Evolutionär psykologi fokuserar främst på "varför?" frågor, medan traditionell psykologi fokuserar på "hur?" frågor.
Premisser
Evolutionspsykologi bygger på flera grundläggande premisser
Hjärnan är en informationsbehandlingsenhet, och den producerar beteende som svar på externa och interna inputs.
Hjärnans adaptiva mekanismer formades av naturligt och sexuellt urval.
Olika neurologiska mekanismer är specialiserade för att lösa problem som funnits i mänsklighetens evolutionära förflutna.
Hjärnan har utvecklat specialiserade neurologiska mekanismer som designades för att lösa problem som återkom under hela evolutionen, vilket ger moderna människor ”stenålderssinnen”.
De flesta processer i hjärnan är omedvetna; och de flesta mentala problem som är till synes lätta att lösa är egentligen mer komplexa och hanteras omedvetet av komplexa neurologiska mekanismer.
Människans psykologi består av många specialiserade mekanismer, var och en känslig för olika typer av information eller input. Dessa mekanismer kombineras för att producera manifest beteende.
Historia
Den evolutionärpsykologiska historien började med Charles Darwin, som sa att människor har sociala instinkter som utvecklats av det naturella urvalet. Darwin´s arbete inspirerade därefter psykologer som William James och Sigmund Freud men för majoriteten av 1900-talet fokuserade psykologer mest på behaviorism och proximala förklaringar för mänskligt beteende. Edward O. Wilsons banbrytande bok Sociobiology (1975), syntetiserade nya teoretiska framsteg inom evolutionsteori för att förklara socialt beteende hos djur, inklusive människor. Jerome Barkow, Leda Cosmides och John Tooby gjorde termen ”evolutionär psykologi” populär i deras bok år 1992 The adapted mind: Evolutionary Psychology and The Generation of Culture.
1800-talet
Efter Charles Darwins betydelsefulla arbete i att utveckla teorin om den naturella selektionen, ägnade han sina sista år i livet till att studera djurs känslor och psykologi. Han skrev två böcker år 1871; The Descent of man, och Selection in Relation to Sex. År 1872 skrev han The expression of the emotions in man and animals som relaterade till ämnen som kan relateras till evolutionär psykologi. Han introducerade teorier angående ”group selection och ”kin selection” för att förklara altruism. Darwin funderade över varför människor och djur så ofta är generösa till sina gruppmedlemmar. Han drog slutsatsen att medan generositet minskar fitness för en individ, så ökar det det total fitness för hela gruppen. Detta innebär att altruism uppstod på grund av konkurrens mellan grupper. Följande citat, från Darwins Origin of Species, tolkas ofta av evolutionära psykologer som en indikation på att han förebådar fältets framväxt:
"I en avlägsen framtid ser jag öppna fält för mycket viktigare forskning. Psykologi kommer att baseras på en ny grund, den nödvändiga förvärvandet av varje mental kraft och kapacitet genom gradering."
— Darwin, Charles (1859). The Origin of Species
1900-talet
Darwins Teori inspirerade William James funktionalistiska approach till psykologi. Kärnan i hans teori var ett system av ”instikter”. James skrev att människor hade många instinkter, till och med fler än andra djur. Han sa, att dessa instinkter, kunde åsidosättas av erfarenhet och av varandra, eftersom många av instinkterna faktiskt var i konflikt med varandra.
I sin Evolutionary Psychology Primer noterar Tooby och Cosmides James perspektiv och citerar även honom:
"Vi inser inte att "normalt" beteende alls behöver förklaras. Denna "instinktblindhet" gör studiet av psykologi svårt. För att komma förbi detta problem föreslog James att vi skulle försöka få det "naturliga att verka konstigt":
Det krävs ... ett sinne som är utsvävat av att lära sig att bära processen att få det naturliga att verka konstigt, så långt att man frågar om varför varje instinktiv mänsklig handling. Enbart för metafysikern kan sådana frågor uppstå som: Varför ler vi när vi är nöjda och inte stirrar? Varför kan vi inte prata med en folkmassa när vi pratar med en enda vän? Varför vänder en viss jungfru vårt förstånd så upp och ner? Den gemene mannen kan bara säga: Självklart ler vi, naturligtvis hjärtklappar vårt hjärta vid åsynen av folkmassan, visst älskar vi jungfrun, den vackra själen klädd i den perfekta formen, så påtagligt och flagrant gjord för all evighet älskade!
Och så, förmodligen, känner varje djur om de särskilda saker som det tenderar att göra i närvaro av särskilda föremål. ... För lejonet är det lejoninnan som är gjord för att bli älskad; till björnen, hon-björnen. För den ruggiga hönan skulle antagligen föreställningen tyckas monstruös att det skulle finnas en varelse i världen för vilken ett bo med ägg inte var det helt fascinerande och dyrbara och aldrig-att-bli-för-mycket-satt-på-objektet som det är. till henne.
Så vi kan vara säkra på att, hur mystiska vissa djurs instinkter än kan verka för oss, kommer våra instinkter att framstå som inte mindre mystiska för dem. (William James, 1890)
De anser att William James hade rätt angående evolutionär psykologi. Att framställa det naturliga som onaturligt är i sig själv onaturligt.
Enligt Noam Chomsky kan den anarkistiska filosofen Pjotr Kropotkin eventuellt vara grundaren av evolutionär psykologi då han i sin bok Mutual Aid: A Factor of Evolution (1902) argumenterar för att mänsklig instinkt till samarbete och altruism kan ses som härstammande från evolutionär adaption.
William McDougall gjorde en referens till evolutionär psykologi i sin bok An Introduction to Social Psychology(1919) där han sa: "It is only a comparative and evolutionary psychology that can provide the needed basis (for psychology); and this could not be created before the work of Darwin had convinced men of the continuity of human with animal evolution as regards all bodily characters, and had prepared the way for the quickly following recognition of the similar continuity of man’s mental evolution with that of the animal world." (p. 16)".
Efter andra världskriget
Medan Darwins teorier angående det naturliga urvalet fick en ökad acceptans under den första halvan av 1900-talet, så blev hans teorier angående evolutionär psykologi i stort sätt ignorerad. Endast efter det andra världskriget, på 1950-talet ökade intresset för ett systematiskt studerande av djurs beteende. Det var under denna period som den moderna etologin växte fram. Konrad Lorenz och Nikolaas Tinbergen var pionjärer inom utvecklandet av det teoretiska ramverket för etologi, vilket ledde till att de fick ett nobelpris år 1973.
Sociobiologi
År 1975 byggde E.O. Wilson vidare på arbetet från Lorenz och Tinbergen genom att kombinera studier av djurs beteende, socialt beteende och evolutionär teori i sin bok Sociobiology: The new Synthesis. Wilson inkluderade ett kapitel om mänskligt beteende. Hans applicering av evolutionär analys på mänskligt var dock inte helt utan upprörda reaktioner.
Genom publiceringen av Sociobiology hade evolutionärt tänkande för första gången en uppenbar närvaro inom psykologin. E.O. Wilson argumenterade för att forskningsfältet evolutionär psykologi essentiellt är samma sak som ”mänsklig sociobiologi”.
Edward H. Hagen skriver i The Handbook of Evolutionary Psychology att sociobiologi, trots det kontroversiella i att applicera den på människor är: "one of the scientific triumphs of the twentieth century." "Sociobiology is now part of the core research and curriculum of virtually all biology departments, and it is a foundation of the work of almost all field biologists". Sociobiologisk forskning på icke mänskliga organismer har ökat dramatiskt och syns konsekvent i världens mest respekterade tidskrifter som Nature och Science. Den mer generella termen beteendeekologi används vanligen som ett substitut för termen sociobiologi då sociobiologi fått ett dåligt rykte av dess kritiker.
Modern användning av termen ”evolutionär psykologi”
Termen evolutionär psykologi användes av den amerikanska biologen Michael Ghiselin i en artikel skriven år 1973. Jerome Barkow, Leda Cosmides och John Tooby gjorde termen evolutionär psykologi populär i sin bok år 1992 The Adapted mind: Evolutionary Psychology and The Generation of culture. Termen förkortas ibland till ”EvoPsych”, evo-psch”, EP etc.
I kontrats till sociobiologi och beteendeekologi, betonar evolutionärpsykologer att organismer är ”adaption executioners” snarare än ”fitness maximizers”. I andra ord så har organismer emotionella, motivationsbaserade och kognitiva adaptioner som generellt ökade organismens fitness under dess evolution, men adaptionen behöver inte göra det idag. Denna skillnad kan förklara vissa maladaptiva beteendet som är ett resultat av "fitness lags" mellan uråldriga och moderna miljöer. Till exempel har människor utvecklat sug efter mat som innehåller fett, socker och salt samt förmågan att bygga upp reserver då man får i sig ett överskott. Denna förmåga har varit fundamentalt viktig för vår överlevnad, men i dagens samhälle där dessa finns tillgängliga i obegränsat utbud leder adaptionen istället till hälsoproblem för oss.
Även, i kontrast till sociobiologi och beteendeekologi (som framförallt studerar icke-mänskliga djurs beteenden), snarare än att fokusera på det explicita beteendet som de gör, så försöker EP att identifiera underliggande psykologiska adaptioner (inkluderat emotionella, motivationsdrivna och kognitiva mekanismer), och även hur dessa mekanismer interagerar med moderna mänskliga miljöer samt mänsklig utveckling för att producera beteenden hos människor.
Innan 1990 pratade knapp introducerande läroböcker inom psykologi knappt på Darwin. På 1990-talet blev evolutionärpsykologin betraktad som en utkantsteori och läroböckernas bevakning var semifientlig. Men idag har det förändrats och evolutionärpsykologer idag anser att läroböckernas täckning är att betrakta som neutral och balanserad.
Närvaron som evolutionsteorin har inom psykologin är stabil och ökande. Idag anser dess förespråkare att evolutionärpsykologin numera ockuperar en central del inom den psykologiska vetenskapen, i riktning till hur det ser ut med evolutionsteorin inom biologin.
Den teoretiska grunden för evolutionär psykologi
Det teoretiska fundamentet för evolutionär psykologi är de generella och de specifika teorierna som förklarar de ultimata ursprunget till psykologiska egenskaper, detta i evolutionära termer. Teorierna har sitt ursprung med Charles Darwin´s forskargärning, inkluderat hans spekulation angående ett evolutionärt ursprung till människans sociala instinkter. Modern evolutionär psykologi må tilläggas är dock endast möjlig på grund av framsteg som gjort inom evolutionsteorin på 1900-talet.
Evolutionärpsykologi säger att det naturliga urvalet har försett människan med flera psykologiska adaptioner, på liknade sätt som den bidragit till människans anatomiska och fysiologiska adaptioner. På samma sätt som för adaptioner generellt, anses psykologiska adaptioner vara specialiserade till den miljö där organismen utvecklades, på engelska ”The environment of evolutionary adaptedness (EEA). Sexuell selektion leder ger organismen adaptioner relaterade till parning. För manliga däggdjur, som har relativt snabb reproduktionsförmåga, leder det sexuella urvalet till anpassningar som hjälper dem att konkurrera om honorna. För kvinnliga däggdjur som har en relativt långsam reproduktionshastighet, leder det sexuella urvalet till att de tvingas välja mer eftertänksamt, vilket hjälper honor att välja partners av högre kvalitet. Charles Darwin beskrev både naturellt och sexuellt urval, men han förlitade sig på ”group selection” för att förklara utvecklingen av altruistiskt beteende. Men ”Group selection” är en svag förklaring, för i en grupp visar det sig att i en grupp kommer mindre altruistiska individer att bli mer troliga att överleva vilket evolutionärt gör grupper mindre altruistiska.
1964 föreslog William D. Hamilton ”inclusive fitness theory”, som betonar en gencentrerad syn på evolution. Hamilton noterade att individer kan öka replikeringen av sina gener till nästa generation genom att hjälpa nära släktingar med vilka de delar gener att överleva och fortplanta sig. Enligt ”hamiltons regel”, kan ett självuppoffrande beteende utvecklas om det hjälper nära släktingar så mycket att det kompenserar för den individuella förlusten av fitness (Om det blir en nettovinst för generna när man tagit vinst för gener i släktingar minus gener för individen själv). Inclusive fitness theory löser frågan angående hur ”altruism” utvecklades. Andra teorier förklarar också utvecklingen av altruistiskt beteende, evolutionär spelteori, tit-for-tat reciprocity (ömsesidighet) och generell ömsesidighet. Teorierna förklarar inte bara evolutionen av altruistiskt beteende, utan redogör också för fientligheten mot fuskare/ free-riders (individer som utnyttjar och drar fördel av andras altruism).
Flera evolutionsteorier på mellannivå hjälper den evolutionära psykologin. r/K selection theory föreslår att vissa arter blomstrar genom att ha flera avkommor medan andra följer strategin att ha färre avkommor men göra en betydligt större investering i varje. Här följer människor den andra strategin. Parental investment Parental investment theory förklarar hur investeringen av tid, energi och resurser som en föräldrar allokerar till en avkommor påverkas av den potentiella vinsten och kostnaden för deras egen reproduktiva framgång. Detta leder till att den reproduktiva strategin och beteendet hos män och kvinnor har skiljt sig under evolutionen på grund i dess olika roller i att producera avkomma. Detta förklarar även varför könsskillnader uppstått mellan män och kvinnor. Enligt Triver-Willard hypotesen tenderar föräldrar i goda förhållanden att investera mer i söner (som är mer benägna att utnyttja goda förhållanden på grund av deras förmåga en högre kvantitet i fortplantningen), medan föräldrar med sämre möjligheter tenderar att investera mer i döttrar (som generellt har en högre framgång även i dåliga förhållanden). Enligt life history theory utvecklar djur genom evolutionen livshistorier som matchar deras miljöer, livshistorierna bestämmer till exempel ålder vid första reproduktion och antal avkommor. Dual inheritance theory (DIT), även kallat gene-culture coevolution theory eller biocultural evoluton, hävdar att gener och mänsklig kultur är integrerat, med gener som påverkar utvecklingen av kultur och kultur i sin tur påverkar mänsklig evolution på en genetisk nivå. DIT kan jämföras med Baldwin effekten, som beskriver hur inlärda beteenden eller egenskaper blir alltmer medfödda genom naturligt urval, vilket så småningom leder till genetiska förändringar av en art.
Kritiker av evolutionspsykologin har ibland utmanat denna teoretiska grund och sagt att människor aldrig utvecklat kraftfulla sociala instinkter genom naturligt urval och att evolutionära hypoteser bara är ”just so stories”.
Allmän evolutionsteori
På samma sätt som att evolutionsteorin grunden för biologin som man alltid måste förhålla sig till så är evolutionsteorin även grunden för evolutionär psykologi. Evolutionspsykologer använder i första teorierna rörande naturligt urval, sexuellt urval och inclusive fitness för att förklara evolution och psykologiska adaptioner
Evolutionär psykologi kan ses som mer än bara en underdisciplin till psykologin utan som en metateoretisk ram där hela psykologin kan undersökas.
Naturligt urval
Evolutionspsykologer anser att Charles Darwins teori om det naturliga urvalet är viktigt för att förstå psykologi. Naturligt urval sker på grund av att enskilda organismer som är genetiskt bättre lämpade för den nuvarande miljön lämnar mer avkomma, och deras gener sprids genom populationen, vilket förklarar varför organismer passar in så bra i deras naturliga miljöer. Denna process är långsam och kumulativ, där nya egenskaper lägger sig i lager över äldre. De fördelar som skapas av naturligt urval kallas adaptioner. Evolutionspsykologer säger att djur, på samma sätt som att de utvecklar fysiska adaptioner, även utvecklar psykologiska adaptioner.
Evolutionspsykologer betonar att naturligt urval oftast genererar specialiserade adaptioner, som är mer effektiva än allmänna än generella adaptioner. De poängterar att det naturliga urvalet fungerar långsamt, och att anpassningar ibland är inaktuella nr miljön förändras snabbt. När det gäller människor säger evolutionärpsykologer att mycket av den mänskliga naturen formades under stenåldern och kanske inte matchar vår samtida miljö.
Sexuellt urval
Det sexuella urvalet gynnar egenskaper som ger parningsfördelar, såsom påfågelns svans, även om dessa egenskaper kan vara ett hinder. Evolutionspsykologer påpekar att, till skillnad från naturligt urval, leder sexuellt urval vanligtvis till utvecklingen av könsskillnader. Könsskillnader gör vanligtvis fortplantningen snabbare för det ena könet och långsammare för det andra, i vilket fall det är relativt partners för könet med snabbare fortplantning. Sexuellt urval gynnar egenskaper som ökar antalet partners för det snabba könet och som ökar kvaliteten för det långsamma könet. För däggdjur har honor den långsammare reproduktionshastigheten. Hanar utvecklar vanligtvis antingen egenskaper för att hjälpa dem bekämpa andra män eller egenskaper för att imponera och attrahera honor. Honor utvecklar vanligtvis förmågor för att urskilja hanarnas egenskaper, såsom att vara mer kräsna (choosiness) vid parning.
Inkluderande fitness (Inclusive fitness)
Inclusive fitness, föreslaget av William D. Hamilton, betonade ett ”genperspektiv” på evolutionen. Hamilton noterade att det som evolutionen i slutändan väljer ut är gener, inte grupper eller arter. Ur detta perspektiv kan individen öka replikeringen av sina gener till nästa generation, inte bara direkt via reproduktion, utan även genom att indirekt hjälpa nära släktingar som de delar gener med att överleva och fortplanta sig. Allmän evolutionsteori, i sin moderna form, är i huvudsak inkluderande fitnessteori.
Inkluderande fitnessteori löste frågan angående hur ”altruism” utvecklades. Den dominerande pre-Hamilton-uppfattningen var att altruism utvecklades genom gruppurval (group selection). Föreställningen att altruism utvecklades till gruppens fördel. Problemet med detta var att om en organism i en grupp ådrog sig en kostnad i fitness på sig själv till förmån för andra i gruppen (dvs agerade altruistiskt), då skulle den organismen minska sin egen förmåga att överleva och/eller fortplanta sig, och ädrav minska sina chanser att före vidare sina altruistiska egenskaper till nästa generation.
Dessutom skulle den organism som gynnades av den altruistiska handlingen och bara agerade för sin egen fitness öka sina chanser att överleva och/eller fortplanta sig, och därmed öka sina chanser att föra sina ”egoistiska” gener vidare. Inkluderande fitness löste ”problemet med altruism” genom uppvisandet att altruism kan utvecklas via anhörigurval (kin selection) vilket uttrycks genom Hamiltons regel:
kostnad < släktskap × nytta
Med andra ord kan altruism utvecklas så länge som fitnesskostnaden för den altruistiska givaren är lägre än (graden av genetiskt släktskap) x (fitnesvinsten för mottagaren). Detta perspektiv återspeglar vad som kallas den gen-centriska synen på evolution och det förklarar varför gruppselektion är en mycket svag selektiv kraft.
Teoretiska grunder
Evolutionsteorier på medelnivå (middle-level evolutionary theories)
Evolutionsteorier på medelnivå överensstämmer med allmän evolutionsteori, men fokuserar på vissa funktionsdomäner. Specifika evolutionära psykologiska hypoteser kan härledas från en teori på medelnivå. Viktiga bidragare till middle-level theories har varit Robert Trivers, Robert MacArthur och E. O Wilson.
Parent-offspring conflict handlar om faktumet att även om en förälder och hens avkomma är 50% genetisk släkt, så är de också 50% genetiskt olika. Med allt annat lika skulle en förälder vilja fördela sina resurser lika mellan sina avkommor, medan varje avkomma kan vilja ha mer än 50% åt sig själv. Dessutom kan en avkomma vilja ha mer resurser från föräldern än vad föräldern är villig att ge. I huvudsak avser konflikt mellan föräldrar och avkomma en konflikt av adaptiva intressen mellan förälder och avkomma. Men om allt inte är lika kan en förälder ägna sig åt diskriminerande investeringar mot den ena eller andra könet, beroende på förälderns tillstånd.
The Trivers-Willard hypothesis, som föreslår att föräldrar kommer att investera mer i det kön som ger dem den största reproduktiva utdelningen (barnbarn) med ökande eller marginella investeringar. Honor är de tyngre föräldrainvesterarna i vår art, på grund av det har honor en bättre chans att fortplanta sig minst en gång jämfört med hanarna, men hanar i goda förhållanden har en bättre chans att producera ett stort antal avkommor jämfört med honor i goda förhållanden. Av den anledningen enligt Trivers-Willard-hypotesen förutsägs föräldrar i gott skick gynna investeringar i söner och föräldrar i sämre skick förutsägs gynna investering i döttrar.
r/K selection theory, som inom ekologin relaterar till selektion av egenskaper som leder till framgång i specifika miljöer. "R-selected species" dvs arter i instabila och i förutsägbara miljöer, producerar en högre kvantitet avkommor, där varje individ har en låg sannolikhet att överleva till vuxenlivet. Som kontrast "K-selected species" innebär att arter i stabila och förutsägbara miljöer, kommer investera mer i ett fåtal avkommor, där varje avkomma har en högre sannolikhet att överleva till vuxenlivet.
Live history theory hävdar att schemat och varaktigheten av nyckelhändelser under en organisms livstid formas av naturligt urval för att producera största möjliga antal överlevande avkommor. För en given individ är tillgängliga resurser i en viss miljö ändliga. Tid, ansträngning och energi som används för ett syfta minskar den tid, ansträngning och energi som finns tillgänglig för ett annat. Exempel på några viktiga livshistoriedelar inkluderar: ålder vid första fortplantningen, reproduktiv livslängd och åldrande samt storlek på avkomman. Variationer i dess egenskaper återspeglar olika allokeringar av en individs resurser (dvs tid, ansträngning och energiförbrukning) till konkurrerande allokeringar (biologisk alternativkostnad). Till exempel anknytningsteorin föreslå att uppmärksamheten man får av föräldern i den tidiga barndomen kan avgöra ens eget förhållande till anknytning. Till exempel finns en studie för att om pappan är frånvarande från hemmet, når flickor den första menstruationen tidigare och har även mer kortvariga sexuella relationer som kvinnor.
Utvecklade psykologiska mekanismer
Evolutionsteorin bygger på antagandet att kognitionen, på samma sätt som hjärtat, lungor, lever, njurar och immunsystem, har en funktionell struktur som har en genetisk grund och därför har utvecklats genom naturligt urval. Liksom att andra organ och vävnader är universellt för en art bör även denna funktionella struktur vara universell för arten och bör lösa viktiga problem rörande överlevnad och reproduktion.
Evolutionspsykologer försöker förstå psykologiska mekanismer genom att förstå de överlevnadsfunktioner och reproduktiva funktioner mekanismerna gav under dess evolutionära historia- Dessa kan ha inkluderat att uppfatta andras känslor, urskilja släktingar från icke släktingar, identifiera släktingar, identifiera och föredra friskare hälsosammare partners, samarbete, och att följa eller sluta följa en ledare. I enlighet med teorin om det naturliga urvalet, ser evolutionärpsykologer att människor ofta är i konflikter med varandra, inkluderat med partners och släktingar. Till exempel kan en mamma vilja avvänja sin avkomma från amning tidigare än hennes spädbarn, vilket gör att mamman kan investera i ytterligare avkommor. Evolutionärpsykologer ser även vikten av anhörigurval (kin selection) och ömsesidighet (reciprocity) i utvecklandet av prosociala egenskaper som altruism. På samma sätt schimpanser och bonoboer har människor subtila och flexibla sociala instinkter, vilket gör att de kan bilda utökade familjer, livslånga vänskaper och politiska allianser.
Ett annat exempel kan vara den utvecklade mekanismen som verkar vid stress och depressioner. Klinisk depression är något maladaptivt, enligt evolutionärpsykologer finns det evolutionära förklaringar till att dessa adaptiva mekanismer finns. Genom evolutionen har människor och djur alltid ha blivit tvungna att kämpa för sin överlevad, vilket har fått våra fight or flight-sinnen välutvecklade och de mekanismerna kan felaktigt aktiveras i vår moderna vardag.
Produkter av evolution: adaptioner, exaptationer, biprodukter och slumpmässig variation
Alla egenskaper hos organismer är inte evolutionära adaptioner. Som kan noteras i tabellen nedan kan egenskaper också vara expationer, biprodukter av anpassningar (ibland kallas ”spandrels” på engelska) eller slumpmässig variation mellan individer.
Psykologiska anpassningar antas vara medfödda eller relativt lätta att lära sig och manifesteras i kulturer över hela världen. Till exempel är förmågan för småbarn att lära sig ett språk med praktiskt taget ingen träning sannolikt en psykologisk anpassning Å andra sidan läste eller skrev våra förfäders människor inte, så idag kräver lärande att läsa och skriva omfattande träning, och antagligen involverar det återanvändning av andra kognitiva förmågor som utvecklats på grund av urvalstryck men till något annat än just till skriftspråk. Variationer till manifest beteende kan dock vara ett resultat av att universella mänskliga mekanismer integreras i olika unika lokala miljöer. Till exempel kommer en person som flyttar närmare eller längre ifrån ekvatorn att få en mörkare/ ljusare hud. Det handlar då inte om att mekanismerna som reglerar pigmentering förändras, utan snarare att inputen till dessa mekanismer förändras, vilket leder till en annan output.
En av den evolutionära psykologins uppgifter är att identifiera vilka psykologiska egenskaper som sannolikt är adaptioner, biprodukter eller slumpmässig variation. George C. Williams föreslog att en ”adaption är ett speciellt och betungande koncept som bara bör användas där det verkligen är nödvändigt”- Som noterats av Williams och andra kan adaptioner identifieras genom deras osannolika komplexitet, artuniversialitet och adaptiv funktionalitet.
Obligatoriska och fakultativa adaptioner
En fråga som kan ställas angående en adaption är, om den är generell obligatorisk (robust inför typisk miljövariation), eller fakultativ (känslig för typisk miljövariation)- Den söta smaken av socker och märtan av att slå knäet mot betong är resultatet av ganska obligatoriska psykologiska adaptioner; typiska miljövariationer under utvecklingen påverkar inte deras funktion mycket- Som kontrast kan fakultativa adaptioner jämföras med ”if-then statements” (om X händer -> i så fall händer Y). Till exempel är vuxnas förhållande till anknytning väldigt känsliga för tidiga upplevelser i barndomen. Som vuxna är benägenheten att utveckla nära, förtroendefulla band med andra som vuxen är beroende på om vårdgivaren under den tidiga barndomen gav individen pålitlig/konsekvent/stabil hjälp och uppmärksamhet. Adaptionen för solbränna är beroende av exponering av solljus, vilket är ett annat exempel på en fakultativ anpassning. När psykologisk anpassning är fakultativ bryr sig evolutionspsykologer om hur inputs från utveckling och miljöfaktorer påverkar adaptionerna som syns hos människor. Ett tredje exempel är en studie som tittar på aggressivitet hos individer, där kombinationen av genetiskt anlag och provocerande input från miljön ledde till högra grad av aggressivitet hos individer (förenklat: anlag + ingen input= ingen aggression, inga anlag + input = ingen aggression, anlag + input= aggression).
Kulturella universaler (cultural universals)
Evolutionspsykologer anser att beteenden eller förekommande egenskaper som finns universellt i alla kulturer är goda kandidater för att vara evolutionära adaptioner. Kulturella universaler inkluderar beteenden relaterat till språk, kognition, soicala roller, könsroller och teknologi. Utvecklade psykologiska adaptioner (såsom förmågan att lära sig ett språk) interagerar med kulturella inputs för att producera specifika beteenden (t.ex. det specifika språket som lärs in).
Grundläggande könsskillnader, såsom större sexuell ivrighet bland män och en större kräsenhet i att välja partner bland kvinnor, förklaras som sexuellt dimorfa psykologiska anpassningar som återspeglar de olika reproduktiva strategierna hos män och kvinnor.
Evolutionspsykologi är en kontrast till vad de kallar ”the standard social science model” (social konstruktivism, relativism och kulturell determinism) som antar att sinnets kognition är av allmän karaktär och att nästan helt kan formas av kulturen. Istället anser evolutionspsykologin att olika kognitiva mekanismer har utformats evolutionärt för att hantera specifika ändamål och som sagt så blir det i slutändan en kombination med de genetiska faktorerna och den unika miljön/ kulturen där individen verkar.
Miljön för den evolutionära adaptionen
Evolutionspsykologin argumenterar för att om man korrekt vill förstå hjärnans funktioner, måste man förstå egenskaperna i miljön där hjärnan utvecklades. Denna miljö kallas ofta ”miljön för evolutionär adaption” (environment of evolutionary adaptedness).
Idén om en miljö av evolutionär adaption utforskades först som en del av anknytningsteorin a John Bowlby. Detta är miljön i vilken en specifik utvecklad mekanism är anpassad till. Med specifikt definieras miljön för evolutionär adaption som den uppsättning av historiskt återkommande urvalstryck som bildade en given adaption, även de aspekter av miljön som var nödvändiga för en korrekt utveckling och funktionering av adaptionen.
Människor, som består av släktet homo, dök upp för mellan 1,5 och 2,5 miljoner år sedan. Eftersom pleistocen (den geologiska epoken) upphörde för bara 12 000 år sedan, utvecklades de flesta mänskliga adaptioner antingen nyligen under pleistocen eller upprätthölls genom ett stabiliserande evolutionärt urval under pleistocen. Evolutionär psykologi föreslår därför att majoriteten av mänskliga psykologiska mekanismer är adapterade till reproduktionsproblem som ofta förekom i just pleistocena miljöer. I stora termer inkluderar dessa problem tillväxt, utveckling, differentiering, underhåll, parning, föräldraskap och sociala relationer.
Miljön för evolutionär adaption skiljer sig väsentligt från det moderna samhället. De moderna människornas förfäder levde i mindre grupper, hade sammanhållna kulturer och hade mer stabila och rika sammanhang för identitet och mening. Forskare kan ofta studera de få överlevande jägare-samlare-samhällena för att få ledtrådar om hur miljön för evolutionär adaption såg ut för jägare-samlare. Tyvärr är de få överlevande jägare- och samlarsamhällena olika varandra och har trängts ut från ursprungsområdet till tuffa miljöer, så det är inte klart hur nära de återspeglar våra förfäders kultur. Runt om i världen erbjuder dock små band av jägare-samlare till exempel ett liknande utvecklingssystem för unga (”hunter-gatherer childgood model” Konner, 2005; och ”evolved developmental niche,” Narvaez et al,. 2013). Egenskaperna för nischen är i stort sett desamma som för sociala däggdjur, som utvecklades för över 30 miljoner år sedan; lugnande perinatal upplevelse (för barn), flera år av amning på begäran, nästan konstant tillgivenhet eller fysisk närhet, lyhördhet för behov, självstyrd lek och för människor framförallt flera lyhörda vårdgivare. Studier visar betydelsen av dessa komponenter i det tidiga livet för positiva utfall för barn.
Evolutonspsykologer vänder sig ibland till schimpanser, bonoboer och andra människoapor för att lära sig om mänskliga förfäders beteende.
Evolutionära felmatchningar (Evolutionary mismatches)
Eftersom organismer var adapterade till dess förfäders miljö, kan en ny och annorlunda miljö skapa en felmatchning. Eftersom människor mestadels adapterats till den pleistocena miljön (som varade från för 2,6 miljoner år sedan till för ca 11 700 år sedan), ger psykologiska mekanismer ibland ”felmatchningar” i den moderna miljön. Ett exempel är det faktum att även om cirka 10 000 människor årligen dödas med vapen i USA, medan spindlar och ormar bara dödar en handfull, lär sig ändå människor lika enkelt att vara rädda för spindlar och ormar som för skarpladdade vapen, och de är ungefär lika rädda för ett oladdat vapen som de är för en kanin eller en blomma. En potentiell förklaring är att spindlar och ormar var ett hot mot mänskliga förfäder under hela pleistocen, medan vapen inte var det. Det finns alltså en bristande överensstämmelse mellan människans utvecklade rädsleinlärnings-psykologi och den moderna miljön.
Denna felmatchning visar sig också i fenomenen med ”the supernormal stimulus”, en stimulans som framkallar ett starkare svar än vad som hade varit möjligt i en stenåldersmiljö. Termen myntades av Nikolaas Tinbergen för att hänvisa till andra djurs beteende, men psykologen Deidre Barett sa att övernaturlig stimulering styr beteenden hos människan lika kraftfullt som för andra djur. Hon förklarade skräpmat som en överdriven stimulans till sug efter salt, socker och fett, och hon säger att TV överdriver sociala signaler såsom skratt, leende, ansikten och uppmärksamhetsfångande "action". Skräpmat aktiverar instinkter som var avsedda för en miljö där fett var ett sällsynt och livsviktigt näringsämne. På samma sätt är drogproblem en evolutionär felmatchning, då vi är adapterade till att gilla det som känns bra och aktiverar våra belöningssystem. Psykologen Mark van Vugt hävdade nyligen att modernt organisatoriskt ledarskap är en felmatchning. Hans argument är att människor inte är anpassade till att arbeta i stora, anonyma, byråkratiska strukturer med formella hierarkier. Det mänskliga sinnet reagerar fortfarande på personligt, karismatiskt ledarskap främst i samband med informella, jämlika miljöer. Därav det missnöje och utanförskap som många anställda upplever. Löner, bonusar och andra privilegier utnyttjar instinkter för relevant status, vilket lockar särskilt män till ledande befattningar.
Forskningsmetoder
Evolutionsteorin är heuristisk genom att den kan generera hypoteser som kanske inte utvecklas från andra teoretiska teoretiska approacher. DVS man använder sig av en kombination av empiriska observationer och intuitiv teoribildning. Ett av huvudmålen med adaptionistisk forskning är att identifiera vilka organismgemenskaper som sannolikt är anpassningar och vilka som är biprodukter eller slumpmässiga variationer. Som nämnts tidigare förväntas adaptioner visa tecken på komplexitet, funktionalitet och artuniversalitet, medan biprodukter eller slumpmässig variation inte kommer göra det. Dessutom förväntas adaptioner manifestera sig som närliggande mekanismer som interagerar med miljön på antingen ett allmänt obligatoriskt eller på ett fakulativt sätt (se ovan). Evolutionspsykologer är också intresserade av att identifiera dessa proximativa mekanismer (ibland kallat ”mentala mekanismer eller ”psykologiska adaptioner”) och vilken typ av information de tas som input, hur de bearbetar den informationen och i slutändan output(Om X händer -> kognition -> output Y). Evolutionär utvecklingspsykologi, eller ”evo-devo” (på engelska), fokuserar på hur anpassningar kan aktiveras vid vissa utvecklingstillfällen (t.ex. att tappa mjölktänder, bli tonnåring etc) eller hur händelser under utvecklingen av en individ kan förändra livshistoriens bana.
Evolutionärpsykologer använder flera strategier för att utveckla och testa hypoteser om huruvida en psykologisk egenskap sannolikt är en utvecklad adaption. Buss (2011) noterar att dessa metoder inkluderar:
Tvärkulturell konsistens (cross-cultural consistency). Egenskaper som har visat sig vara tvärkulturella mänskliga universaler såsom leede, gråta, ansiktsuttryck antas vara utvecklade psykologiska adaptioner. Flera evolutionära psykologer har samlat in enorma datamängder från kulturer rumt om i världen för att bedöma tvärkulturell universalitet. Ett exempel där tvärkulturella universella drag som gås igenom är Brown (1991)
Funktion till form (eller ”problem till lösning”). Det faktum att män men inte kvinnor, riskerar potentiell felaktig identifiering av genetisk avkomma (på engelska ”paternity uncertainty”) fick evolutionära psykologer att anta att manlig svartsjuka, jämfört med kvinnor, skulle vara med fokuserad på sexuell, snarare än känslomässig otrorohet. Exempel på en studie som visar detta är Buss et al (1992)
Form till funktion (reverse-engineering, eller ”lösning på problem)”. Morgonillamående, och tillhörande motvilja mot vissa typer av mat, under graviditeten verkade ha egenskaperna hos en utvecklad adaption (den var komplex och universell för kvinnor i hela världen). Margie Profet antog att funktionen var för att undvika intag av gifter under tidig graviditet som kan skada fostret (men som annars sannolikt är ofarliga för friska icke-gravida kvinnor).
Motsvarande neurologiska moduler (corresponding neurological modules). Evolutionspsykologi och kognitiv neuropsykologi är ömsesidigt kompatibla: evolutionär psykologi hjälper att identifiera psykologiska adaptioner och deras ultimata evolutionära funktioner, medan neuropsykologer hjälper till att identifiera de proximativa manifestationerna av dessa adaptioner. Exempel på studie är (Kanwisher (2000)
Aktuell evolutionär adaptivitet (current evolutionary adaptiveness). Förutom evolutionära modeller som typer på att evolution sker över stora tidsperioder, har ny forskning visat att vissa evolutionära forändringar kan vara snabba och dramatiska. Följaktligen har vissa evolutionärpsykologer fokuserat på effekterna av psykologiska egenskaper i den nuvarande miljön. Sådan forskning kan användas för att informera om uppskattningar av förekomsten av egenskaper över tid. Sådant arbete har varit informativt för att studera evolutionär psykopatologi. En studie som till exempel tittar på depression i vår nuvarande miljö och hur det relaterar till adaptioner på grund av historiskt evolutionärt tryck är Nettle (2004).
Evolutionärpsykologer använder också datakällor för testning, inklusive experiment, arkeologiska register, data från jägare-samlare, observationsstudier, neurovetenskapliga data, självrapporter och undersökningar, offentliga register och mänskliga produkter. Nyligen har ytterligare metoder och verktyg introducerats baserade på fiktiva scenarier, matematiska modeller och ”multi-agent computer simulations”.
Huvudområden för forskning inom ämnet
Grundläggande forskningsområden inom evolutionär psykologi kan delas in i de breda kategorier av adaptiva problem som uppstår direkt ur evolutionsteorin: Parning, föräldraskap, familj och släktskap, interaktioner med icke-släktingar och kulturell evolution.
Överlevnad och psykologiska adaptioner på individnivå
Överlevnadsproblem är tydliga mål för evolutionen av fysiska och psykologiska adaptioner. Stora problem som förfäderna till dagens människor stod inför inkluderar, val och förvärv av föda, val av territorium, samt att undvika rovdjur och andra hot från miljön.
Medvetande
Medvetandet uppfyller George Williams kriterier för artens universalitet, komplexitet och funktionalitet, och det är en egenskap som uppenbarligen ökar graden av fitness.
I sin artikel ”Evolution of consciousness” hävdar John Eccles att speciella anatomiska och fysiska Adaptioner av hjärnbarken (cereblar cortex) hos däggdjur gav upphov till medvetande. I motsats härtill har andra hävdat att de rekursiva kretsar som är grunden för medvetandet är mycket mer primitiva, efter att ha utvecklats initialt i pre-däggdjursarter eftersom de förbättrar förmågan till interaktion med både sociala och naturliga miljöer genom att tillhandahålla en energibesparande ”neutral” förmåga i en annars högt energikonsumerande motor-outputs-maskin. Väl på plats kan denna rekursiva krets mycket väl ha gett en grund för den efterföljande utvecklingen av många av de funktioner som medvetandet underlättar i högre organismer, som beskrivits av Bernard J. Baars. Richard Dawkins föreslog att människor utvecklade medvetandet för att göra sig själva till föremål för tanken. Daniel Povinelli föreslog att stora, trädklättrande apor utvecklade medvetande för att ta hänsyn till sin egen massa när de rör sig bland trädgrenar. I överensstämmelse med denna hypotes fann Gordon Gallup att schimpanser och orangutanger, men inte små apor eller marklevande gorillor, visade självmedvetenhet i spegeltestet.
Begreppet medvetande kan syfta på frivillig handling, medvetenhet, eller vakenhet. Men även frivilligt beteende involverar omedvetna mekanismer. Många kognitiva processer äger rum i det kognitiva omedvetna, otillgängliga för medveten medvetenhet. Vissa beteenden är medvetna när de lärs in men blir sedan omedvetna, till synes automatiska. Inlärning, särskilt inlärning av en färdighet, kan ske utanför medvetandet. Till exempel vet många människor hur man svänger till höger när de cyklar, men väldigt få kan exakt förklara hur de faktiskt gör det. Evolutionär psykologi närmar sig även självbedrägeri som en anpassning som kan förbättra resultatet i sociala utbyten.
Sömnen kan ha utvecklats för att spara energi när aktivitet skulle vara mindre fruktsamt eller farligare, som på natten, och under vintersäsongen.
Sensation och perception
Många experter, så som Jerry Fodor, anser att syftet med perception är kunskap, men evolutionära psykologer menar att dess primära syfte är att vägleda handling. Till exempel säger de att den djupa perceptionen inte tycks ha utvecklats för att hjälpa oss veta avstånden till andra objekt utan snarare för att hjälpa oss att röra oss i en tredimensionell miljö. Evolutionära psykologer säger att djur allt ifrån spelmanskrabbor till människor använder synen för att undvika kollisioner, vilket tyder på att syn i grunden finns för att styra handling, och inte för att ge kunskap.
Att bygga och underhålla sinnesorgan är metaboliskt dyrt, så dessa organ utvecklades endast när de förbättrar en organisms fitness. Mer än halva hjärnan används för att bearbeta sensorisk information, och själva hjärnan förbrukar ungefär en fjärdedel av de metabola resurserna, så sinnena måste ge exceptionella fördelar för en organisms fitness. Perception speglar världen exakt; djurs sinnen ger därför dem användbar och korrekt information om omvärlden.
Forskare som studerar perception och sensation har länge förstått de mänskliga sinnena som adaptioner till deras omgivande miljö. Djup perception består av att bearbeta ett antal signaler, som var och en är baserad på en regelbundenhet i den fysiska världen. Synen utvecklades för att reagera på det smala intervallet elektromagnetisk energi som är riklig och som inte passerar genom föremål. Ljudvågor kan gå runt hörn och interagera med hinder, vilket skapar ett komplext mönster som innehåller användbar information om källorna till och avstånden till objekt. Större djur ger naturligt ifrån sig lägre/ djupare ljud som en konsekvens av sin storlek. Intervallet av ljud som ett djur kommer kunna uppfatta styrs däremot av adaption. Målduvor, till exempel, kan höra det mycket låga ljudet (infraljud) som kan nå stora avstånd, även om de flesta mindre djur upptäcker högre ljud. Smak och lukt reagerar på kemikalier i miljön som tros ha haft betydelse för fitness i miljön för ett djurs evolutionära adaption. Till exempel var salt och socker tydligen både värdefulla för de mänskliga eller pre-mänskliga invånarna i miljön av evolutionär adaption, vilket resulterar i att dagens människor har ett inneboende sug efter salta och söta smaker. Sinnet känsel är egentligen flera sinnen, inklusive tryck, värme, kyla, kittling och smärta. Smärta, även om den är obehaglig är adaptiv. En viktig anpassning för sinnena är räckviddsförskjutning, varigenom organismen tillfälligt blir mer eller mindre känslig för sensation. Till exempel anpassar ögonen sig automatiskt till svagt eller starkt omgivande ljus. Sensoriska förmågor hos olika organismer utvecklades ofta samtidigt, vilket är fallet med hörseln av ekolokaliserande fladdermöss och den hos nattfjärilar som har utvecklats som en reaktion till ljudet som fladdermössen gör (för att undvika predation).
Evolutionspsykologer hävdar att perception demonstrerar principen om modularitet, med specialiserade mekanismer som hanterar särskilda perceptionsuppgifter. Till exempel har personer med skada på en viss del av hjärnan den specifika defekten att inte kan känna igen ansikten (prosopangnosia). Evolutionspsykologer antyder att detta indiktera en så kallad ansiktsläsningsmodul (face-reading module).
Lärande och fakultativa adaptioner
Inom evolutionär psykologi sägs lärande åstadkommas genom utvecklade kapaciteter, särskilt fakultativa adaptioner. Fakultativa adaptioner uttrycker sig olika beroende på input från miljön. Ibland kommer input under utvecklingen och hjälper till att forma den. Till exempel lär sig flyttfåglar att orientera sig efter stjärnorna under en kritisk period i sin mognad. Evolutionspsykologer tror att människor också lär sig språk genom ett utvecklat program, även med kritiska perioder. Inmatningen (input) kan också komma under dagliga uppgifter, vilket hjälper organismen att hantera förändrande miljöförhållanden. Till exempel utvecklade djur pavloviansk betingning (klassisk betingning) för att lösa problem om orsakssamband (t.ex. att ett spädbarn testar att släppa eller kasta leksaker). Djur löser inlärningsuppgifter enklast när de liknar de problem som de ställdes inför i sitt evolutionära förflutna, såsom en råtta som lär sig var man kan hitta mat eller vatten. Inlärningsförmåga visar ibland skillnader mellan könen. Hos många djurarter till exempel, kan hanar lösa spatiala problem snabbare och mer exakt än honor, på grund av effekter av manligt hormon under utvecklingen. Detsamma kan vara sant för människor.
Känslor och motivation
Motivationer styr och stimulerar beteende, medan känslor ger den affektiva komponenten till motivation, positiv eller negativ. I början av 1970-talet började Paul Ekman och hans kollegor ett forskningsfält som antyder att många känslor är universella. Han fann bevis för att människor delar minst fem grundläggande känslor: rädsla, sorg, lycka, ilska och avsky. Sociala känslor utvecklades uppenbarligen för att motivera sociala beteenden som var gynnsamma i miljön av vår evolutionära adaption. Till exempel skam och stolthet kan motivera beteenden som hjälper en individ att behålla sin ställning i ett samhälle, och självkänsla är ens uppskattning av ens status. Motivation har en neurobiologisk grund i hjärnans belöningssystem. Nyligen har det föreslagits att belöningssystem kan utvecklas på såtant sätt att det kan finnas en inneboende eller oundviklig avvägning i motivationssystemet för aktiviteter av kort eller lång varaktighet.
Kognition
Kognition avser interna representationer av världen och intern informationsbehandling. Ur ett evolutionärt psykologiskt perspektiv har kognition inte ett ”allmänt syfte”, utan använder heuristik, eller strategier, som generellt ökar sannolikheten att lösa ett problem som våra förfäder rutinmässigt stod inför. Till exempel är dagens människor mycket mer benägna att lösa logiska problem som involverar att upptäcka fusk (vanligt problem i den evolutionära miljön och i sociala miljöer), jämfört med samma logiska problem uttryck i rent abstrakta termer. Eftersom våra förfäder inte stötte på riktigt slumpmässiga händelser, kan dagens människor vara kognitivt predisponerade för att felaktigt identifiera mönster i slumpmässiga sekvenser. ”Gambler´s fallacy” är ett exempel på detta, spelare kan felaktigt tro att de har träffat en ”lyckoserie” även när varje resultat faktiskt är slumpmässigt och oberoende av tidigare försök. De flesta tror att om ett mynt kastats nio gånger och det blivit krona varje gång, så är det på det tionde kastet en större sannolikhet än 50 % att få klave. Människor har mycket lättare att ställa diagnoser eller förutsägelser med hjälp av frekvensdata än när samma information presenteras som sannolikheter eller procentsatser, förmodligen eftersom förfäderna till dagens människor levde i relativt små stammar (vanligtvis med färre än 150 personer) där frekvensinformation var mer lättillgänglig.
Personlighet
Evolutionspsykologi är främst intresserad av att hitta gemensamma drag mellan människor, eller grundläggande mänsklig psykologisk natur. Ur ett evolutionärt perspektiv är det faktum att människor har grundläggande skillnader i personlighetsdrag initialt något av ett pussel. (Notera: området beteendegenetik handlar om att statistiskt fördela skillnader mellan människor i genetiska och miljömässiga varianskällor. Det kan dock vara svårt att förstå begreppet ärftlighet – ärftlighet avser bara skillnaderna mellan människor, aldrig i vilken grad egenskaper hos en individ beror på miljömässiga eller genetiska faktorer, eftersom egenskaper alltid är en komplex sammanvävning av båda.)
Personlighetsdrag föreställs av evolutionärpsykologer som beroende på normal variation kring ett optimum, på grund av frekvensberoende urval (behavioural polymorphism), eller som fakultativa adaptioner. Liksom variationer i kroppslängd kan vissa personlighetsdrag helt enkelt återspegla inter-individuell variation kring ett allmänt optimum. Eller så kan personlighetsdrag representera olika genetiska predisponerade ”beteendemorfer” – alternativa beteendestrategier som beror på frekvensen av konkurrerande beteendestrategier i befolkningen. Till exempel, om de flesta i en befolkning generellt är förtroendefulla och godtrogna, kan beteendetypen att vara en ”fuskare” (eller i extreme fall en sociopat) vara fördelaktigt. Slutligen, liksom många andra psykologiska adaptioner, kan personlighetsdrag vara fakultativa – känsliga för typiska variationer i den sociala miljön, särskilt under den tidiga utvecklingen. Till exempel är senare födda barn mer benägna än förstfödda att vara upproriska, mindre samvetsgranna och mer öppna för nya upplevelser, vilket kan vara fördelaktigt för dem med tanke på deras speciella nisch i familjestrukturen. Det är viktigt att notera att delad miljöpåverkan (för syskon) spelar en roll för personligheten och inte behöver vara mindre betydande än genetiska faktorer. Effekten av delad miljöpåverkan minskar ofta efter tonåren men försvinner inte helt.
Språk
Enligt Steven Pinker, som bygger på Noam Chomskys arbete, innebär den universella mänskliga förmågan att lära sig prata i åldrarna 1-4, i princip utan träning, att språkinlärning är en distinkt mänsklig psykologisk adaption (se särskilt, Pinkers bok: The language instinct). Pinker och Bloom (1990) hävdar att språket som mental förmåga delar många likheter med kroppens komplexa organ, vilket tyder på att språket, liksom dessa har utvecklats som en adaption, eftersom detta är den enda kända processen för utvecklingen av såpass komplexa organ i organismer.
Pinker följer Chomsky och hävdar att, det faktum att barn kan lära sig vilket mänskligt språk som helst utan någon explicit instruktion tyder på att språket, inklusive det mesta av grammatiken, i grunden är medfött och att det bara behöver aktiveras genom interaktion. Chomsky själv tror inte att språket har utvecklats som en adaption, men anytder att det troligen har utvecklats som en biprodukt av någon annan adaption (en så kallas ”spandrel”). Men Pinker och Bloom hävdar att språkets organiska natur talar starkt för att det har ett adaptivt ursprung.
Evolutionspsykologer anser att FOXP2-genen mycket vär kan vara associerad med utvecklingen av mänskligt språk. På 1980-talet identifierade psykolingvistikern Myrna Gopnik en dominant gen som orsakade språkstörningar i "KE familjen" i Storbritannien. Denna gen visade sig vara en mutation av FOXP2-genen. Människor har en unik allel av denna gen, som annars har varit nära bevarad genom större delen av däggdjurs evolutionära historia. Denna unika allel verkar ha uppstått för första gången för mellan 100 och 200 tusen år sedan, och är nu nästan universell hos människor. Men den en gång så populära idén att FOXP2 är en ”gramatikgen” eller att den utlöste framväxten av språk i Homo sapiens är nu allmänt avfärdad.
För närvarande finns det flera konkurrerande teorier om språkets evolutionära ursprung och ingen allmän konsensus. Forskare av spåkinlärning hos primater och människor som Michael Tomasello och Talmy Givón, hävdar att det innatiska ramverket har underskattat rollen av imitation i inlärning och att det inte alls är nödvändigt att påstå att det finns en medfödd grammatikmodul som förklarar mänskligt språk. Tomasello hävdar att studier av hur barn och primater faktiskt förvärvar kommunikativa färdigheter tyder på att människor lär sig komplext beteende genom erfarenhet, så att istället för en modul specifik tillägnad språkinlärning, förvärvas språk av samma kognitiva mekanismer som används för att förvärva alla andra slag av socialt överfört beteende.
När det gäller frågan om huruvida språk bäst ses som att ha utvecklats som en adaption eller som en biprodukt, hävdar evolutionsbiologen W. Tecumseh Fitch att det är obefogat att anta att varje aspekt av språket är en adaption, eller att språket som helhet är en adaption. Han kritiserar vissa delar av den evolutionära psykologin för att antyda en pan-adaptionistisk syn på evolutionen (ett antagande att alla egenskaper finns på grund av naturligt urval), och han avfärdar Pinker och Blooms fråga om huruvida ”språk har utvecklats som en adaption” som vilseledande. Han hävdar istället att ur en biologisk synvinkel är språkets evolutionära ursprung bäst konceptualiserat som det troliga resultatet av en konvergens av många separata adaptioner till ett komplext system. Ett liknande argument framförs av Terrence Deacon som i boken ”The symbolic Species” hävdar att språkets olika egenskaper har utvecklats tillsammans med sinnets och att förmågan att använda symbolisk kommunikation är integrerad i alla andra kognitiva processer.
Om teorin angående att språket kunde utvecklats som en enda adaption accepteras, blir frågan vilken av dess flera funktioner som har legat till grund för adaptionen. Flera evolutionära hypoteser har ställts: att språket utvecklats till syfte för social gemenskap, att det utvecklades som ett sätt att visa parningspotential eller att det utvecklades för att bilda sociala kontrakt. Evolutionspsykologer inser att alla dessa teorier är spekulativa och att det krävs mycket mer bevis för att förstå hur språket kan ha blivit evolutionärt adapterat.
Parning
Eftersom sexuell reproduktion är det sätt på vilket gener förökas till framtida generationer, spelar sexuellt urval en stor roll i människans evolution. Människors parning är alltså av intresse för evolutionspsykologer som syftar till att undersöka utvecklade mekanismer för att attrahera och säkra partners. Flera forskningslinjer har utgått från detta, såsom studier av partnerval, mate poaching, kvarhållande av partners och konflikt mellan könen.
1972 publicerade Robert Trivers en inflytelserik artikel om könsskillnader som nu kallas föräldrainvesteringsteorin (parental investment theory). Storleksskillnaden mellan könsceller (anisogami) är den grundläggande, definierande skillnaden mellan män (små könsceller – spermier) och kvinnor (stora könsceller – ägg). Trivers noterade att anisogami vanligtvis resulterar i olika nivåer av föräldrainvestering i avkomman mellan könen, dä kvinnor initialt investerar mer. Trivers föreslog att skillnaden i föräldrarainvestering leder till sexuell selektion av olika reproduktiva strategier och även till sexuella konflikter. Till exempel föreslog han att det kön som investerar mindre i avkomman i allmänhet kommer tävla om tillgång till det högre investerande könet för att öka sin egen inkluderande fitness. Trivers hävdade att skillnader i föräldrainvestering ledde till utvecklingen av sexuell dimorfism inom partnerval, intra- och intersexuell konkurrens samt uppvaktning. Hos däggdjur inklusive människor, gör honor en mycket större föräldrainvestering än män (dvs dräktighet följt av förlossning och amning). Föräldrainvesteringsteorin är en del av ”livshistorieteorin” (life history theory).
Buss och Schmitts (1993) Sexual Strategies Theory föreslog att människor, på grund av olika föräldrainvestering, har utvecklat sexuellt dimorfa adaptioner relaterade till ”sexuell tillgänglighet” (sexual accessibility), fertilitetsbedömning, engagemangssökande eller undvikande, omedelbar och bestående resurssanskaffning, faderskapssäkerhet, bedömning av partnerns reproduktionsvärde och föräldrainvestering. Deras strategic Interference Theory föreslog att konflikter mellan könen uppstår när det ena könets föredragna reproduktionsstrategi krockar med det andra könets och, vilket resulterar i känslomässiga reaktioner som ilska eller svartsjuka.
Kvinnor är i allmänhet mer selektiva än män när de väljer partner, särskilt under långvariga parningsförhållanden. Men under vissa omständigheter kan kortvarig parning också ge fördelar för kvinnor, såsom fertilitetsförsäkring, för att ”byta till sig” bättre gener, minskad risk för inavel och försäkringsskydd för avkomman.
Manlig osäkerhet kring faderskapet, har resulterat i könsskillnader när det kommer till sexuell svartsjuka. Kvinnor reagerar generellt mer negativt på känslomässig otrohet och män kommer att reagera mer på sexuell otrohet. Detta speciella mönster förutsägs eftersom kostnaderna för parning är olika. Kvinnor föredrar i allmänhet en partner som kan erbjuda resurser (t.ex. ekonomiska, eller i form av engagemang) och förlorar resurser med en partner som begår känslomässig otrohet. Män å andra sidan, har aldrig under evolutionen varit säkra på det genetiska faderskapet eftersom de inte bär sin avkomma själv. Detta antyder att sexuell otrohet i allmänhet skulle väcka starkare känslor för män på grund av att en investering av resurser i en annan mans avkomma inte leder till spridning av deras egna gener.
En annan intressant forskningslinje är den som undersöker kvinnors partnerpreferenser över ägglossningscykeln. Den teoretiska grunden för denna forskning är att kvinnliga förfäder skulle ha utvecklat mekanismer för att välja partners med vissa egenskaper beroende på deras hormonella status. Hypotesen om ägglossningsförskjutning (the ovulatory shift hypothesis), hävdar att under ägglossningsfasen (ca dag 10-15 av cykeln) skulle en kvinna som parat sig med en hane med hög genetisk kvalitet ha högre sannolikhet för att producera och föda en frisk avkomma än en kvinna som parat sig med en hane med låg genetisk kvalitet. Dessa förmodade preferenser förutspås vara särskilt uppenbara för kortvariga parningsdomäner eftersom en potentiell manlig partner bara skulle erbjuda gener till en potentiell avkomma och inget mer. Hypotesen låter forskare undersöka om kvinnor väljer partners med egenskaper som indikerar hög genetisk kvalitet under den del ägglossningscykeln som har högst fertilitet. Studier har visat att kvinnors preferenser varierar över ägglossningscykeln. I synnerhet visar Haselton och Miller (2006) att mycket fertila kvinnor föredrar kreativa men fattiga män som kortvariga partners efrersom kreativitet kan vara en indikation på bra gener. Forskning av Gangestad et al. (2004) indikerar att mycket fertila kvinnor föredrar män med social närvaro och intrasexuell konkurrens; dessa egenskaper kan fungera som ledtrådar som hjälper kvinnor att förutsäga vilka män som kan ha, eller skulle kunna skaffa henne resurser.
Föräldraskap
Reproduktion är alltid kostsamt för kvinnor, och kan också vara det för män. Individer är begränsade i vilken grad de kan ägna tid och resurser till att producera och föda upp sina unga, och sådana utgifter kan också vara skadliga för deras framtida tillstånd, överlevnad och ytterligare reproduktiv produktion. Föräldrarnas investering är alla de utgifter (tid, energi etc.) som gynnar en avkomma till en kostnad för föräldrarnas förmåga att investera i andra komponenter av sin fitness (Clutton-Brock 1991: 9; Trivers 1972). Fitnesskomponenter inkluderar välbefinnande hos befintliga avkommor, föräldrarnas framtida reproduktion och fitness med hjälp av anhöriga (Hamilton 1964). Föräldrainvesteringsteorin (parental investment theory) är en gren av ”livshistoria” (life history theory).
Fördelarna med föräldrarnas investeringar för avkomman är stora och förknippade med effekterna på kondition, tillväxt, överlevnad och i slutändan på avkommans reproduktiva förmåga. Dessa fördelar kan dock komma på bekostnad av förälderns förmåga att fortplanta sig i framtiden t.ex. genom en ökad risk för skador vid försvar av avkomman mot rovdjur, förlust av parningsmöjligheter vid uppfödning av avkomma och förlängning av tiden till nästa reproduktion. Sammantaget väljs föräldrar ut (av det naturliga urvalet) för att maximera skillnaderna fördelarna och kostsnaderna, och föräldravården kommer sannolik att utvecklas när fördelarna överstiger kostnaderna.
Askungseffekten (the cinderella effect) är en påstådd hög förekomst av att styvbarn blir utatta för fysiska, känslomässiga eller sexuella övergrepp, eller blir försummade, mördade eller på annat sätt misshandlade av sina styvföräldrar i betydligt högre grad än deras genetiska motsvarighet. Den har fått sitt namn efter sagofiguren askungen, som blev grymt misshandlad av sin styvmor och styvsystrar. Daly och Wilson (1996) noterade:
”Evolutionärt tänkande ledde till upptäckten av den viktigaste riskfaktorn för barnmord – närvaron av en styvförälder. Föräldrarnas ansträngningar och investeringar är värdefulla resurser, och naturligt urval gynnar de föräldrars psyken som allokerar ansträngningar effektivt till att främja sin egen inkluderande fitness (gens eye evolution). De adaptiva problem som utmanar föräldrarnas beslut inkluderar både korrekt identifiering av avkomman och allokering av ens resurser, bland dem lyhördhet för deras behov och förmåga att omvandla föräldrarnas investering till ökning av fitness. Styvbarn var sällan eller aldrig så värdefulla för ens förväntade fitness som den egen avkomman skulle vara, och de föräldrar som drogs till att hjälpa vilken unge som helst (i ett primitivt scenario under evolutionen) måste ha ådragit sig en selektiv nackdel” (Daly & Wilson, 1996).
De konstaterade dock att inte alla styvföräldrar kommer att ”vilja” misshandla sin partners barn och att genetiskt förldraskap inte är någon försäkring mot övergrepp. De ser stsyvföräldravården som primärt en ”parningsansträngning” (mating effort) gentemot den genetiska föräldern.
Familj och släkt
Inkluderande fitness är summan av en organisms klassiska fitness (hur många av sin egen avkomma den producerar och försörjer) och antalet ekvivalenter av sin egen avkomma den kan lägga till populationen genom att stödja andra. Den första komponenten kallas klassisk fitness av Hamilton (1964).
Ur genens perspektiv beror evolutionär framgång i slutändan på att man lämnar bakom sig det maximala antalet kopior av sig själv i befolkningen. Fram till 1964 trodde man allmänt att gener endast uppnådde detta genom att få individen att lämna det maximala antalet livskraftiga avkommor. Men 1964 bevisade W.D. Hamilton matematiskt att, eftersom nära släktingar till en organism delar några identiska gener, kan en gen också öka sin evolutionära framgång genom att främja reproduktionen och överlevnaden av dessa besläktade eller på annat sätt liknande individer. Hamilton drog slutsatsen att detta leder till att naturligt urval gynnar organismer som skulle bete sig på ett sätt som maximerar deras inkluderande fitness. Det är också sant att naturligt urval gynnar beteende som maximerar personlig fitness.
Hamiltons regel beskriver matematiskt hur en gen för altruistiskt beteende kommer att spridas i en population eller inte:
rb > c
Där
c är reproduktionskostnaden för altruismen
b är den reproduktiva fördelen för mottagaren av det altruistiska beteendet
c är sannolikheten över populationsgenomsnittet för individer som delar en altruistisk gen – vanligen sett som ”grad av släktskap”
Konceptet tjänar till att förklara hur naturligt urval kan upprätthålla altruism. Om det finns en ”altruismgen” (eller ett komplex av gener) som påverkar en organisms beteende för att vara hjälpsam och skyddande för släktingar och deras avkomma, ökar detta beteende också andelen av altruismgenen i befolkningen, eftersom släktingar sannolikt delar gener med den som är altruistisk på grund av gemensam härkomst. Altruister kan också ha något sätt att känna igen altruistiskt beteende hos obesläktade individer ock vara benägna att stödja dem. Som Dawkins påpekar i ”The selfish Gene (kapitel 6) och ”the extended phenotype, måste detta särskiljas från the green-beard effect (se engelska Wikipedia).
Även om människor generellt settvtenderar att vara mer altruistiska mot sina anhöriga än mot icke-släktingar, har de relevanta närliggande mekanismerna som förmedlar detta samarbete diskuterats. Det finnss vissa som hävdar att anhörigstatus bestäms främst via sociala och kulturella faktorer (som co-residance, maternal association of siblings etc), medan andra hävdar att släktigenkännande också kan förmedlas av biologiska faktorer som ansiktslikhet och immunogenetisk likhet med stora histokompatibilitetskomplexet (MHC). Se Lieberman, Tooby och Cosmides (2007) för en diskussion om interaktionen mellan dessa sociala och biologiska faktorer för släktigenkänning.
Oavsett de proximativa mekanismerna för släktigenkänning finnss det betydande bevis för att människor i allmänhet agerar altruistiskt gentemot nära genetiska släktingar jämfört med genetiska icke-släktingar.
Interaktion med icke-släktingar/ ömsesidighet (reciprocity)
Även om interaktioner med icke-släktingar i allmänhet är mindre altruistiska jämfört med interaktioner med anhöriga, kan samarbete upprätthållas med icke-släktingar via ömsesidigt fördelaktig ömsesidighet (mutually beneficial reciprocity) som föreslogs av Robert Trivers (1971). Om det finns upprepade möten mellan samma två spelare i ett evolutionärt spel där var och en av dem kan välja att antingen ”samarbeta” eller ”bedra”, så kan en strategi för ömsesidigt samarbete gynnas även om det lönar sig för varje spelare på kort sikt, att hoppa bedra när den andra samarbetar. Direkt ömsesidighet kan leda till utveckling av samarbete endast om sannolikheten, ”w”, för ett annat möte mellan samma två individer överstiger kostnads-nyttoförhållandet (cost-to-benefit ratio) för den altruistiska handlingen:
w > c/b
Ömsesidighet kan också vara indirekt om information rörande tidigare interaktioner delas. Rykten tillåter utveckling av samarbete genom indirekt ömsesidighet. Naturligt urval gynnar strategier som baserar beslutet att hjälpa på mottagarens rykte: studier visar att människor som är mer hjälpsamma är mer benägna att få hjälp. Beräkningarna av ömsesidighet är komplicerade och endast en liten bråkdel av detta har avslöjats, men återigen har en enkel regel dykt upp. indirekt ömsesidighet kan bara främja samarbete om sannolikheten, ”q” för att känna till någons rykte överstiger kostnads-nyttoförhållandet för den altruistiska handlingen:
q > c/b
Ett viktigt problem med denna förklaring är att individer eventuellt kan utveckla förmågan att dölja sitt rykte, vilket minskar sannolikheten, ”q”, att det kommer bli känt.
Trivers hävdar att vänskap och olika sociala känslor utvecklades för att hantera ömsesidighet. Att tycka om eller att ogilla någon har enligt Trivers utvecklats för att hjälpa våra förfäder att bilda koalitioner med andra som var ömsesidigt hjälpsamma och utesluta dem som inte var det. Moralisk indignation kan ha utvecklats för att förhindra att ens altruism utnyttjas av fuskare, och tacksamhet kan ha motiverat våra förfäder att återgälda på lämpligt sätt efter att ha dragit nytta av andras altruism. Likaså känner dagens människor skuld när de misslyckas med att återgälda. Dessa sociala motiv matchar vad evolutionära psykologer förväntas se i adaptioner som utvecklats för att maximera fördelarna och minimera nackdelarna med ömsesidighet.
Evolutionspsykologer anser att människor har psykologiska adaptioner som utvecklats specifikt för att hjälpa oss att identifiera icke-ömsesidiga personer (nonreciprocators), vanligen kallade ”fuskare”. År 1993 fann Robert Frank och hans medarbetare att deltagare i ett fångarnas dilemma-scenario ofta kunde förutsäga om deras partner skulle fuska baserat på en halvtimmes ostrukturerad social interaktion. I ett experiment från 1996 fann Linda Mealey och hennes kollegor till exempel att människor var bättre på att komma ihåg andras ansikten när de var förknippade med berättelser om individerna som fuskare.
Stark ömsesidighet (Strong reciprocity or ”tribal reciprocity”)
Människor kan ha en uppsättning av psyologiska adaptioner som predisponerar dem för att i vissa situationer vara mer samarbetsvilliga än vad som vanligtvis förväntas för medlemmar av en tribal in-grupp, och mer fientlig mot medlemmar av en tribal out-group. Dessa adaptioner kan ha varit en konsekvens av stamkrigföring. Då krig och konflikt mellan grupper har varit en central del av människans miljö för evolutionär adaption antar evolutionspsykologin att dessa adaptioner finns. Wrangham och Glowacki (2012) fann till exempel tydliga likheter i hur krigföring bedrivs genom jämförande av hur schimpanser och mänskliga jägare-samlare: hanar skapade koalitioner med syfta att attackera andra grupper ofta med dödlig utgång, territoriala konflikter med andra grupper för att försvara sitt territorium eller utvidga det, smygattacker som att göra skada på outgroups med en låg risk, och ”costly signaling” där individer deltar för att öka sin status och respekt i gruppen.
Människor kan också ha anlag för altruistisk bestraffning (”altruistic punishment”) – att straffa medlemmar i gruppen som bryter mot reglerna i gruppen, även när detta altruistiska beteende inte kan motiveras i termer av att hjälpa dem de är släkt med (kin selection), att samarbeta med dem som de kommer att interagera med igen (direct reciprocity), eller samarbeta för att förbättra sitt rykte hos andra (indirect reciprocity). Neurologiska experiment av De Quervain et al (2004) visade att områden i hjärnan kopplade till belöning aktiverades då människor straffade andra som de upplevde vara ”fuskare”.
Evolutionär psykologi och kultur
Även om evolutionär psykologi traditionellt fokuserat på beteenden på individnivå, bestämt arttypiska psykologiska adaptioner, har avsevärt arbete gjorts på hur dessa adaptioner formar och i slutändan styr kulturen. Tooby och Cosmides (1989) menade att sinnet består av många domänspecifika psykologiska adaptioner, av vilka några kan begränsa vilket kulturellt material som lärs ut.i motsats till ett domängenerellt kulturellt (mentalt) förvärvsprogram, där en individ passivt tar emot kulturellt överfört material från gruppen, hävdar bland annat Tooby och Cosmides (1989) att:
”psyket utvecklades för att generera adaptivt snarare än repetitivt beteende, och analyserar därför kritiskt beteenden hos dem som omger det på mycket strukturerade och mönstrade sätt, för att användas som en rik (men inte på något sätt den enda) informationskällan för att konstruera en ”privat kultur” eller ett individuellt anpassat adaptivt system; Följaktiglen kan detta system spegla andras beteende i någon givet avseende eller inte.” (Tooby and Cosmides 1989)
Biologiska förklaringar av mänsklig kultur förde också kritik mot evolutionär psykologi: Evolutionspsykologer ser det mänskliga psyket och fysiologin som en genetisk produkt och antar att gener innehåller informationen för utveckling och kontroll av organismen och att denna information överförs från en generation till den nästa via gener. Evolutionspsykologer ser därmed fysiska och psykologiska egenskaper hos människor som genetiskt programmerade. Även då evolutionära psykologer erkänner miljöns inflytande på mänsklig utveckling, förstår de miljön endast som en aktivator eller utlösare för de programmerade utvecklingsinstruktionerna kodade i gener.
Evolutionspsykologer tror till exempel att den mänskliga hjärnan är uppbyggd av medfödda moduler, som var och en är specialiserad endast för mycket specifika uppgifter, t.ex en ångestmodul. Enligt evolutionspsykologer ger dessa moduler innan organismen faktiskt utvecklats och aktiveras sedan av någon miljöhändelse. Kritiker invänder att denna uppfattning är reduktionistisk och att kognitiv specialisering endast kommer till stånd genom interaktion mellan människor och sin verkliga miljö, snarare än miljön hos avlägsna förfäder. Tvärvetenskapliga tillvägagångssätt strävar i allt högre grad efter att förmedla mellan dessa motsatta synpunkter och att framhäva att biologiska och kulturella orsaker inte behöver vara antitetiska när det gäller att förklara mänskligt beteende och till och med komplexa kulturella prestationer.
Två exempel för hur evolutionär psykologi kan förklara kultur
Ett exempel på hur evolutionspsykologer kan förklara kultur är exemplet med matpreferenser. Under hela mänsklighetens historia behövde våra förfäder identifiera vilka livsmedel som var säkra att äta och vilka som var potentiellt skadliga. Förmågan att skilja mellan dessa alternativ var avgörande för överlevnaden, och individer som effektivt kunde analysera och anpassa sig till sin miljö hade en bättre chans att föra sina gener vidare.
I detta sammanhang är den "privata kulturen" individens förmåga att lära av andras beteenden i sitt samhälle samtidigt som den anpassar sig till sina specifika omständigheter. Till exempel kan en person observera andra i sin grupp som konsumerar en viss typ av frukt och undviker en annan. Genom att observera detta mönster kan individen dra slutsatsen att den föredragna frukten är säker att äta och den andra inte. Men den här personen kan också ha personliga erfarenheter som formar deras preferenser, såsom en allergi eller ett positivt möte med en tidigare undviken mat. Detta skulle leda till skapandet av en "privat kultur" eller individuellt anpassat adaptivt system som kan skilja sig från gruppens allmänna praxis.
Ursprungsbefolkningen på Trobriandöarna
Ett annat exempel som stödjer den evolutionära psykologiska synen på kultur kan ses i kularingsystemet, det bytessystem som praktiseras av Trobriands invånare i södra Stilla havet. Kularingsystemet en är ett komplext system för ceremoniellt gåvoutbyte som involverar handel med värdefulla föremål, såsom skalhalsband och armband, bland ett nätverk av öar.
Det evolutionära psykologiska perspektivet skulle hävda att systemet uppstod eftersom det gav adaptiva fördelar för de deltagande individerna och grupperna. Genom att delta i detta gåvoutbyte kunde Trobriands invånare etablera och upprätthålla sociala relationer, bilda allianser och visa sin sociala status. Dessa interaktioner ökade samarbetet, minskade konflikter och underlättade delning av resurser, vilket i slutändan främjade överlevnad och reproduktion av individer inom dessa grupper.
I det här exemplet kan kulturen för hela gruppen (eller stammen) ses som ett adaptivt system som uppstod för att lösa specifika sociala och ekologiska utmaningar som Trobriands invånare ställs inför. Bytessystemet har utvecklats över tiden för att passa de specifika behoven i denna gemenskap, och är ett exempel på hur kultur kan formas av principerna för evolutionär psykologi.
Delområden inom psykologi
Utvecklingspsykologi
Evolutionär utvecklingspsykologi (EDP) är ett forskningsparadigm som tillämpar de grundläggande principerna för evolution genom naturligt urval, för att förstå utvecklingen av mänskligt beteende och kognition. Detta involverar studer av både de genetiska och miljömässiga mekanismerna som ligger till grund för utvecklingen av sociala och kognitiva kompetenser, såvär som de epigenetiska processer som anpassar dessa kompetenser till lokala förhållanden.
De viktigaste för principerna för evolutionär utvecklingspsykologi är:
Evolutionärt ursprung: EDP antar att mänskligt beteende och kognition har formats av naturligt urval under miljontals år av evolution. Det syftar till att identifiera de adaptiva funktionerna hos psykologiska egenskaper, som har gått fört fram genom det naturliga urvalet
Interaktion mellan gener och miljö: EDP antar att mänskligt beteende är resultatet av komplexa interaktioner mellan genetiskt anlag och miljö. Den studerar hur dessa interaktioner bidrar till utvecklingen av psykologiska egenskaper under en individs livslängd
Medfödda predispositioner: EDP hävdar att människor föds med vissa kognitiva och emotionella anlag, som har utvecklats för att hjälpa dem att lösa specifika adaptiva problem. Dessa anlag är inte fixerade utan interagerar med omgivningen för att producera olika beteenderesultat
Känsliga perioder: EDP hävdar att det finns vissa kritiska eller känsliga perioder i utvecklingen när vissa upplevelser har en större inveckan på en individs psykologiska utveckling. Dessa perioder kan ha utvecklats för att de optimerar individens förmåga att anpassa sig till specifika miljöutmaningar
Domänspecifika inlärningsmekanismer: EDP föreslår att människor har specialiserade kognitiva mekanismer som har utvecklats för att bearbeta specifika typer av information.
Enligt Paul Baltes minskar fördelarna med evolutionärt urval med åldern. Naturligt urval har inte eliminerat flera skadliga tillstånd och icke-adaptiva egenskaper som förekommer bland äldre vuxna, såsom Alzheimers. Om det var en sjukdom som dödade 20-åringar istället för 70-åringar kan detta ha varit en sjukdom som naturligt urval kunde ha eliminerat för evigheter sedan. Således utan hjälp av evolutionära påtryckningar mot icke-adaptiva förhållanden, lider moderna människor av åldrandets värt, smärta och svagheter och eftersom fördelarna med evolutionärt urval minskar med åldern, ökar behovet av moderna teknologiska medier mot icke-adaptiva förhållanden.
Socialpsykologi
Eftersom människor är en mycket social art finns det många adaptiva problem förknippade med att navigera i den sociala världen (t.ex. att upprätthålla alliderade, hantera statushierarkier, integrera med utgruppsmedlemmar, koordinera sociala aktiviteter, kollektivt beslutsfattande). Forskare inom det framväxande området evolutionär socialpsykologi har gjort många upptäckter som hänfört sig till ämnen som traditionellt studerats av socialpsykologer. Inklusive personuppfattning, social kognition, attityder, altruism, känslor, gruppdynamik, ledarskap, motivation, fördomar, intergruppsrelationer och tvärkulturella skillnader.
När man strävar efter att lösa ett problem visar människor i tidig ålder beslutsamhet medan schimanser inte har något jämförbart ansiktsuttryck. Forskare misstänker att det mänskliga uttrucket har utvecklats på grund av att när en människa bestämt arbetar med ett problem kommer andra människor ofta och hjälper till.
Onormal/ Abnormal psykologi
Adaptionistiska hypoteser angående etiologin av psykologiska störningar är ofta baserade på analogier mellan fysiologiska och psykologiska dysfunktioner, som noteras i tabellen nedan. Framstående teoretiker och evolutionspsykiatriker inkluderar Michael T. McGuire, Anthony Stevens och Randolph M. Nesse. De tre, med fler, antyder att psykiska störningar beror på de interaktiva effekterna av både gener och miljö (”nature and nurture”), och ofta har flera bidragande orsaker.
Evolutionspsykologer har föreslagit att schizofreni och bipolär sjukdom kan återspegla en bieffekt av gener med fitnessfördelar, såsom ökad kreativitet. Vissa individer med bipolär sjukdom är särskilt kreativa under sina maniska faser och nära släktingar till personer med schizofreni har visat sig vara med benägna att ha kreativa yrken. En rapport från 1994 från American Psychiatry Association fann ungeffär samma frekvens av personer med schizofreni i västerländska och icke-västerländska kulturer, och i industrialiserade och pastorala samhällen, vilket tyder på att schizofreni inte är en civilisationssjukdom eller en godtycklig social uppfinning utan en bieffekt av en stabil egenskap som bevisligen klarar det naturliga urvalet.
Sociopati kan representera en evolutionärt stabil strategi, genom vilken ett litet antal människor vid fuskar på sociala kontrakt gynnas i ett samhälle som mestadels består av icke-sociopater. Mild depression kan vara ett adaptivt svar för att dra sig tillbaka från, och omvärdera, situationer som har lett till ofördelaktiga resultat (the analytical rumination hypothesis) (se (eng wikipedia ”Evolutionary approaches to depression).
En del av dessa spekulationer har ännu inte utvecklats till helt testbara hypoteser, och det krävs en hel del forskning för att bekräfta deras giltighet.
Antisocialt och kriminellt beteende
Evolutionär psykologi har blivit applicerat för att förklara brott och andra typer av omoraliskt beteende som adaptivt eller relaterat till adaptivt beteende. Män är generellt mer aggressiva än kvinnor, som är mer selektiva i sitt val av partners på grund av deras betydligt högre invstering i att producera avkomma. Att män är mer aggressiva antas bero på ett de på grund av att vara det mindre investerande könet hamnar i en mer intensiv konkurrens med varandra. Det kan ha varit evolutionärt fördelaktigt att ägna sig åt mycket riskfyllt och våldsamt aggressivt beteende för att öka sin status och därmed sin reproduktiva framgång. Detta kan förklara varför män i allmänhet är inblandade i fler brott, och varför män av låg status samt ogifta män är mer förknippade med kriminalitet. Dessutom hävdas konkurrensen om kvinnor att ha varit särskilt intensiv i sena tonåren och ung vuxen ålder, vilket ses som en förklaring till att brottsligheten är särskilt hög under denna period.
Sociologen Lee Ellis i hans (Evolutionary neuroandrogenic theory) ENA, hävdar att olika exponering av androgener är anledningen till kriminellt beteende. Ramverket försöker förstå könsskillnader i mänskligt beteende och deras evolutionära grund. ENA-teorin hävdar att könsskillnader i beteende har utvecklats som ett resultat av olika urvalstryck för män och kvinnor. Dessa skillnader tros ha format uttrycket och funktionen av androgener i hjärnan, vilket i sin tur påverkar beteenden såsom aggression, risktagande och vilja att tävla. Teorin betonar androgenernas roll som förmedlare av dessa beteendeskillnader, och kopplar utvecklingen av könsspecifika beteenden till de hormoner som reglerar dem.
Nyckelaspekter:
1. Evolutionärt tryck: hanar och honor har mött olika urvalstryck genom evolutionen, vilket har lett till utvecklingen av könsspecifika beteenden. Till exempel antas män ha mött större konkurrens om partners och resurser, vilket leder till utveckling av ökad aggression och risktagande.
2. Androgenexponering: Variationer av androgennivåer, särskilt testosteron, under prenatal utveckling och senare i livet tros påverka uttrycket av könsspecifika beteenden.
Många konflikter som leder till skada och död involverar status, rykte och till synes triviala förolämpningar. Steven Pinker hävdar i sin book The better angels of our nature att i icke-statliga samhällen utan polis var det mycket viktigt att ha en trovärdig avskräckning mot aggrssion. Därför var det viktigt att uppfattas som att ha ett trovärdigt rykte för vedergällning, vilket resulterade i att människor utvecklade hämndinstinkter att skydda ryktet (hedern). Pinker hävdar att utvecklingen av staten och polisen dramatiskt har minskat våldsnivåerna jämfört med förfädernas miljö. Om statens våldsmonopol slutar att fungera, vilket kan vara lokalt i en stats fattiga områden, organiserar sig människor igen i grupper för skydd och aggression. Koncept som våldsam hämnd och upprätthållande av heder blir återigen väldigt viktigt.
Evolutionspsykologin för religion
Religionens evolutionära psykologi är studiet av religiös tro med hjälp av evolutionära psykologiska mekanismer. Forskare hålle i allmänhet med om tanken på att benägenhet att engagera sig i religiöst beteende utvecklades tidigt i mänskligheten historia. Det rådet dock oenighet om de exakta mekanismerna som drev utvecklingen av det religiösa sinnet.
Det finns två skolor. Den ena är att religionen själv utvecklades på grund av naturligt urval och är en adaption, i vilket fall religionen gav någon form av evolutionär fördel. Den andra är att religiösa ögertygelser och beteenden, såsom konceptet med en protogud, kan ha uppstått som en biprodukt av andra adaptiva egenskaper utan att först väljas ut på grund av sina egna fördelar. Ett tredje förslag är att olika aspekter av religion kräver olika evolutionära förklaringar men också att olika evolutionära förklaringar kan gälla flera aspekter av religion.
Religiöst beteende innebär ofta betydande kostnader – inklusive ekonomiska kostnader, celibat, farliga ritualer eller att spendera tid som skulle kunna användas på annat sätt. Detta skulle typa på att naturligt urval bör agera mot att religiöst beteende skulle utvecklas såvida det inte det eller andra förklaringar gör att religiöst beteende har betydande fördelar.
Religion som en adaption
Ytterligare information (engelska Wikipedia): ”Psychological adaption”, ”handicap principle”, ”Signalling theory”
Richard Sosis och Candace Alcorta har granskat flera av de framstående teorierna för religionens adaptiva värde. Många är ”sociala solidaritetsteorier”, som anser att religion har utvecklats för att förbättra samarbete och sammanhållning inom grupper. Gruppmedlemskap ger i sin tur fördelar som kan öka en individs chanser till överlevnad och reproduktion. Dessa fördelar sträcker sig från samordningsfördelar till att underlägga kostsamma beteenderegler.
Sosis undersökte också 200 utopiska kommuner i 1800-talets USA, både religiösa och sekulära (mestadels socialistiska). 39 % av de religiösa kommunerna fungerade fortfarande 20 år efter grundandet medan endast 6 % av de sekulära kommunerna gjorde det. Antalet kostsamma uppoffringar som en religiös kommun krävde av sina medlemmar hade en linjär effekt på dess livslängd, medan kraven på kostsamma uppoffringar i sekulära kommuner inte korrelerade med livslängden och majoriteten av de sekulära kommunerna misslyckades inom 8 år. Sosis citerar antropologen Roy Rappaport för att hävda att rigualer och lagar är mer effektiva när de sekraliseras. Socialpsykologen Jonathan Haidit citerar Sosis forskning i sin bok The righteous mind (2012) som det bästa beviset på att religion är en adaptiv lösning på ”the free-rider problem” genom att möjliggöra samarbete utan släktskap. Evolutionsmedicinforskaren Randolph M. Nesse och den teoretiska biologen Mary Jane West-Eberhard har istället hävdat att eftersom människor med altruistiska tendenser föredras som sociala parter får de fitnessfördelar genom socialt urval, med Nesse som vidare argumenterar att sociala urval möjliggjorde människor som en art att bli utomordentligt samarbetsvilliga och kapabla till att skapa kultur.
Edward O. Wilsons teori om ”eusocialitet” (eusociality) pekar starkt på gruppsammanhållning som drivkraften för religionens utveckling. Wilson hävdar att individerna av en liten andel arter (inklusive Homo sapiens, myror, termir, bin och några fler) replikerar sina gener genom att ansluta sig till en av ett antal konkurrerande grupper. Han postulerar vidare att det hos Homo sapiens tack vare deras stora frontallob, utvecklade ett komplext samspel mellan grupputveckling och individuell utveckling inom en grupp.
Dessa sociala solidaritetsteorier kan hjälpa till att förklara den smärtsamma eller farliga naturen hos många religiösa rigualer. Teori om kostsam signalering tyder på att sådana ritualer kan fungera som offentliga och ”hard-to-fake” signaler om att en idivids engagemeang för en grupp är uppriktig. Eftersom det skulle vara en avsevärd fördel med att försöka lura systemet – att drafördel av grupplivsförmåner utan att ta på sig några eventuella kostnader – skulle rigualen inte vara något enkelt som kan tas lätt på. Krigföring är ett bra exempel på en grupplevnadskostnad, och Richard Sosis, Howard C. Kresso ch James S. Boster genomförde en tvärkulturell undersökning som visade att män i samhällen som engagerar sig i krig underkastar sig de dyraste ritualerna.
Studier som visar mer direkta positiva samband mellan religiös utövning och hälsa och livslängd är mer kontroversiella. Harold G. KOenig och Harvey J. Cohen sammanfattade och bedömde resultaten av 100 evidensbaserade studier som systematiskt undersökte sambandet mellan religion och mänskligt välbefinnande, och fan att 79% visade ett positivt inflytande. En annan studie av Gail Ironson visade att tro på gud och en stark känsla av andlighet korrelerar med en lägre grad av infektion och förbättrade immuncellsnivåer hos HIV-patienter. Men en debatt pågår fortfarande och korrelationsfynden visar nödvändigtvis inte en direkt kausalitetssamband mellan religion och hälsa. Mark Stibich hävdar att det finns en tydlig korrelation men att orsaken till det fortfrande är oklar. En kritik mot sådana praceboeffekter, såväl som fördelen med att religion ger en känsla av mening, är att det verkar troligt att mindre komplexa mekanismer än religiöst beteende skulle uppnå sådana mål.
Religion som en biprodukt
Stephen Jay Gould nämner religion som ett exempel på en expatation eller spandrel, men han väjer inte själv en bestämd egenskap som han tror att det naturliga urvalet faktiskt har agerat på. Han tar dock upp Freuds förslag att våra stora hjärnor, som utvecklats av andra skäl, ledde till medvetande. Medvetandets början tvingade människor att ta itu med begreppet personlig dödlighet. Religion kan ha varit en lösning på detta problem.
Andra forskare har föreslagit specifika psykologiska processer som naturligt urval kan ha främjat vid sidan av religionen. Sådana mekanismer kan inkludera förmågan att sluta sig vid närvaron av organismer som kan göra skada (agentdetektering), förmågan att komma med orsaksberättelser för naturhändelser (etiologi) och förmågan att känna igen att andra människor har sina egna sinnen med sina egna övertygelser och avsikter (theory of mind). Dessa tre anpassningar (bland andra) tillåter människor att föreställa sig målmedvetna agenter bakom många observationer som inte lätt kunde förklaras på annat sätt, t.ex. åska, blixtar, planeternas rörelser, livets komplexitet.
Pascal Boyer föreslår i sin bok Religion Explained (2001) att det inte finns någon enkel förklaring till religiöst medvetande. Han bygger på idéerna från de kognitiva antropologerna Dan Sperber och Scott Atran, somn hävdade att religiös kognition representerar en biprodukt av olika evolutionära adaptioner, inklusive folkpsykologi. Han menar att en sådan faktor är att det i de flesta fall har varit fördelaktigt för människor att komma ihåg ”minimalt kontraintuitiva” begrepp som skiljer sig något från den dagliga rutinen och som bryter mot medfödda förväntningar om hur världen är uppbyggd. En gud som i många aspekter är som en människa men mycket mer kraftfull är ett sådant koncept, medan den ofta mycket mer abstrakta guden som diskuteras utförligt av teologer ofta är för kontraintuitiv. Experiment stödjer att religiösa människor tänker på sin gud i antropomorfa termer även om detta strider mot de mer komplexa teologiska doktrinerna i deras religion.
Pierre Leinard och Pascal Boyer föreslår att människor utvecklat ett ”hazard-precaution system” som gjorde det möjligt för dem att upptäcka potentiella hot i miljön och försöka reagera på lämpligt sätt. Flera drag av rituella beteenden, ofta ett viktigt inslag i religion, anses utlösa detta system. Dessa inkluderar tillfället för ritualen (ofta förebyggande eller eliminering av fara eller ondska), den skada som tros vara resultatet av att ritualen inte utförs och de detaljerade anvisningarna för korrekt genomförande av ritualen. Leinard och Boyer diskuterar möjligheten att ett känsligt ”hazard-precaution system” i sig kan ha gett fitnessfördelar, och att religionen sedan ”associerar individuell, ohanterlig ångest med att samordna handlingar med andra och därigenom göra dem mer hanterbara och meningsfulla.
Justin L. Barret i Why Would nyone Believe in God? (2004) föreslår att tron på grud är naturlig eftersom den beror på mentala verktyg som alla människor besitter. Han föreslår att strukturen och utvecklingen av mänskliga sinnen gör tron på existensen av en gud (med egenskaper som att vara allvetande, allmäktig och odödlig), mycket attraktiv. Han jämför också tro på Gud med tro på andra sinnen, och ägnar ett kapitel åt att titta på ateismens evolutionära psykologi. Han föreslår att en av de grundläggande mentala modulerna i hjärnan är ”Hyperactive Agency Detection Device” (HADD), ett annat potentiellt system för att identifiera fara. HADD kan ge en överlevnadsfördel även om den är överkänslig: det är bättre att undvika ett inbillat rovdjur än att bli dödad av ett på riktigt. Detta skulle tendera att uppmuntra tro på fantiserade saker såsom spöken och andar.
Även om hominider antagligen började använda sin framväxande kognitiva förmåga för att tillgodose grundläggande behov som näring och parning, hävdar Terror management theory att detta hände innan de hade nått den punkt där betydande självmedenhet uppstod. Medvetenhet om döden blev en mycket störande biprodukt av tidigare adaptiova funktioner. Den resulterande ångesten hotade att undergräva just dessa funktioner och behövde därför hanteras. Varje social formation eller praxis som skulle accepteras allmänt av massorna behövde tillhandahålla ett sätt att hantera sådan terror. den huvudsakliga strategin för att göra det var att ”bli en individ av värde i en värld av mening” och att ”förvärva självkänsla via skapade och upprätthållande av en kultur”, eftersom detta skulle motverka känslan av obetydlighet som representerades av döden. Samt ge: 1) symbolisk odödlighet genom arvet från kultur som lever vidare bortom det fysiska jaget (jordisk betydelse), och 2)bokstavlig odödlighet, löftet om ett liv efter detta eller fortsatt existens som förekommer religioner (kosmisk betydelse).
Religion som ett ”Meme”
Richard Dawkins föreslår i The Selfish Gene (1976) att kulturella memes fungerar som gener genom att de är föremål för naturligt urval. I The God Delusion (2006) hänvar Dawkins vidare att eftersom religiösa sanningar inte kan ifrågasättas, uppmuntrar deras natur att de sprider sig som ”mentala virus”. I en sådan uppfattning är det nödvändigt att de individer som inte kan ifrågasätta sin tro är mer biologiskt fit än de individer som är kapabla att ifrågasätta sin tro. Således kunde man dra slutsatsen att heliga skrifter eller muntliga traditioner skapade ett beteendemönster som höjde den biologiska lämpligheten för troende individer. Individer som var kapabla att utmana sådana föreställningar, även om trosuppfattningarna var oberhört osannolika, blev sällsyntare och sällsyntare i befolkningen. (se eng Wikipedia: ”denialism”)
Denna modell hävdar att religion är en biprodukt av de kognitiva modulerna i den mänskliga hjärnan som uppstod i det evolutionära förflutna för att hantera problem med överlevnad och reproduktion. Initiala begrepp om övernaturliga medel kan uppstå i människors tendens att ”överupptäcka” närvaron av andra människor eller rovdjur (till exempel: att tillfälligt missta en pinne för en orm). Till exempel kan en man rapportera att han kände någon smyga sig på, men det försvann när han såg sig omkring.
Berättelser om dessa upplevelser kommer särskilt sannolikt att återberättas, föras vidare och försköna på grund av deras beskrivningar av standardontologiska kategorier (person, artefakt, djur, växt, naturligt objekt) med kontraintuitiva egenskaper (människor som är osynliga, hus som minns vad som hände dem etc.). Dessa berättelser blir ännu mer framträdande när de åtföljs av aktivering av icke-kränkta förväntningar på den ontologiska kategorin (hus som ”minns” aktiverar vår intuitiva sinnespsykologi; d.v.s. vi tillskriver dem automatiskt tankeprocesser).
Ett av attributen för vår intuitiva sinnespsykologi är att människor är intresserade av andra människors angelägenhet. Detta kan resultera i en tendens för begrepp om övernaturliga agenter att oundvikligen korskoppla med mänskliga intuitiva moraliska känslor (evolutionära beteenderiktlinjer). Dessutom skapar närvaron av döda kroppar ett obekvämt kognitivt tillstånd där drömmar och andra mentala moduler (personifiering och beteendeförutsägelse) förtsätter att köra frikopplat från verkligheten, vilket producerar oförenliga intuitioner att de döda på något sätt fortfarande finns kvar. När detta är kopplat till den mänskliga predispositionen att se olycka som en social händelse (som någons ansvar snarare än ett resultat av mekaniska processer) kan det aktivera den intuitiva modulen ”villighet att göra utbyten” i den mänskliga teorin om sinnen, vilket tvingar de sörjande att försöka integrera och förhandla med övernaturliga medel (ritual).
I en tillräckligt stor grupp kommer vissa individer att verka bättre skickliga på dessa ritualer än andra och kommer att bli specialister. När samhällen växer och möter andra samhällen kommer konkurrens att uppstå och en ”survival of the fittest”-effekt kan få utövarna att modifiera sina koncept för att ge en mer abstrakt, mer allmänt acceptabel version. Så småningom bildar specialistutövarna en sammanhållen grupp enner skrå med åtföljande politiska mål (religion).
Koalitionspsykologi
Koalitionspsykologi är en approach för att förklara politiska beteenden mellan olika koalitioner och villkorligheten i dessa beteenden, ur ett evolutionärt psykologiskt perspektiv. Detta tillvägagångssätt förutsätter att sedan människor dök upp på jorden har det utvecklats till att leva i grupper istället för att leva som individer för att uppnå fördelar, som fler parningsmöjligheter, säkerhet och ökad status. Människan tänker och handlar naturligt på ett sätt som hanterar gruppdynamik.
Koalitionspsykologi erbjuder falsifierbara ex ante prediktioner genom att ställa fem hypoteser angående hur denna psykologiska adaption fungerar:
Människor representerar grupper som en speciell kategori av individer, instabilar och ofta kortsiktiga.
Politiska entreprenörer manipulerar strategiskt den koalitionsmässiga miljön för att inspirera till kollektiv handling.
Relativa vinster dominerar relationen mellan fiender, men absoluta vinster kännetecknar relationer mellan allierade.
Koalitionsstorlek och manligt fysisk styrka kommer positivt att förutsäga individuellt stöd för aggressiv utrikespolitik.
Individer med barn, särskilt kvinnor, kommer att variera i ett anta aggressiv utrikespolitik än de som är utan avkomma.
Mottagande och kritik
Kritiker av evolutionär psykologi anklagar den för att främja genetisk determinism, pan-adaptionism (tanken att alla beteenden och anatomiska egenskaper är adaptioner), icke falsifierbara hypoteser, distala eller ultimata förklaringar för beteende när proximativa förklaringar anses bättre, och att det kan gynna illvilliga politiska idéer.
Etiska implikationer
Kritiker hävdar att evolutionär psykologi kan användas för att rättfärdiga existerande sociala hierarkier och reaktionär politik. Det har också föreslagits av kritiker att evolutionärpsykologers teorier och tolkningar av empiriska data i hög grad bygger på ideologiska antaganden om etnicitet och kön.
I respons till sådan kritik varnar evolutionära psykologer ofta för att begå det naturalistiska felslutet – antagandet att ”det som är naturligt” nödvändigtvis är det moraliskt goda. Evolutionspsykologer menar inte att till exempel aggression är en bra sak bara för att de förklarar det som något naturligt förekommande, tvärt om anser de att man med förståelsen om vad man har att göra med bättre kan hantera och förebygga dessa typer av problem. Men kritikerna återigen anklagar evolutionspsykologerna för att gömma sig bakom det naturalistiska felslutsargumentet för att kväva en legitim nödvändig etisk diskussion angående ämnet.
Motsägelser i modeller
En del kritik av evolutionär psykologi pekar på motsättningar mellan olika aspekter av adaptiva scenarier som evolutionär psykologi ställer. Ett exempel är den evolutionära psykologiska modellen för utökade sociala grupper som selekteras för moderna mänskliga hjärnor, en motsägelse är att den synaptiska funktionen hos moderna mänskliga hjärnor kräver höga mängder av många specifika essentiella näringsämnentt en sådan övergång till högre krav på samma essentiella näringsämnen delas av alla individer i en population skulle minska möjligheten att bilda stora grupper på grund av flaskhals-mat med sällsynta essentiella näringsämnen som begränsar gruppstorleken. Det nämns att vissa insekter har samhällen med olika rangordning för vajre individ och att apor förblir socialt fungerande efter att större delen av hjärnan tagits bort som ytterligare argument mot att stora hjärnor främjar socialt nätverkande. Modellen med hanar som försörjare och beskyddare kritiseras för att det är omöjligt att var apå två ställen samtidigt, hanen kan inte både skydda sin familj hemma och vara ute och jaga samtidigt. I fallet med påståendet att en man som försörjer sin familj kunde köpa skyddstjänster för sin familj av andra män genom att byta mat som han jagat, pekar kritiker på det faktum att den mest värdefulla maten (maten som innehöll de mest sällsynta essentiella näringsämnena) olika i olika ekologier och i vissa geografiska områden och djur i andra, vilket gör det omöjligt för jaktstilar som förlitar sig på fysisk styrka eller risktagande att vara universellt av liknande värde i byteshandel och istället för att göra det oundvikligt att i vissa delar i Afrika skulle mat som samlats in utan behov av större fysisk styrka vara den mest värdefulla att byta mot skydd. En motsägelse mellan evolutionspsykologins påståense om att män måste vara mer sexuellt visuella än kvinnor för att snabbt kunna bedöma kvinnors fertilitet än kvinnor behövde för att kunna bedöma mannens gener och dess påstående om manlig sexuell svartsjuka som skyddar mot otrohet, pekas också på, som det skulle vara meningslöst för en hane att vara snabb att bedöma kvinnlig fertilitet om han behövde bedöma risken för att det finns en svartsjuk manlig partner och i såfall hans chanser att besegra honom innan parning ändå (menignslöshet att bedöma ett nödvändigt tillstånd snabbare än ett annat nödvändigt tillstånd kan möjligen bedömas)
Standard social science model
Evolutionspsykologi har intrasslats i de större filosofiska och samhällsvetenskapliga kontroverserna relaterade till debatten om natur kontra näring (nature vs nurture). Evolutionspsykologer kontrasterar vanligtvis evolutionär psykologi med vad de kallar den standardiserade samhällsvetenskapliga modellen (SSSM). De karakteriserar SSSM som ett perspektiv av ”blank slate”, ”relativism”, ”social konstruktivism”, och ”kulturell determinism” som de säger dominerade samhällsvetenskaperna under hela 1900-talet där man antog att sinnet nästan helt formats av kultur.
Kritiker har hävdat att evolutionära psykologer skapade en falsk dikotomi mellan sin egen uppfattning och karikatyren av SSSM. Andra kritiker betraktar SSSM som ett retoriskt redskap eller en straw man och menar att de vetenskapsmän som evolutionära psykologer associerar med SSSM inte trodde att sinne var ett vitt blad utan några naturliga anlag.
Reduktionism och determinism
Vissa kritiker ser evolutionär psykologi som en form av genetisk reduktionism och genetisk determinism, en vanlig kritik är att evolutionär psykologi inte tar upp komplexiteten i en individuell utveckling och erfarenhet och misslyckas med att förklara geners påverkan på beteenden i individuella fall. Evolutionspsykologer svarar att de arbetar inom ett natur-miljö-interaktionistiskt ramverk (nature-nurture interactionist framework) som antar att många psykologiska adaptioner är fakultativa (mänskliga för miljövariationer under individuell utveckling). Discipninen är i allmänhet inte fokuserad på närliggande analyser av beteende, utan dess fokus är snarare på studiet av distal/ ultimat kausalitet (utvecklingen av psykologiska adaptioner). Området beteendegenetik är fokuserat på studiet av geners proximala inflytande på beteende.
Provning av hypoteser
En frekvent kritik är att hypoteserna inom evolutionär psykologi ofta är godtyckliga och svåra eller omöjliga att testa på ett adekvat sätt, vilket ifrågasätter dess status som en faktisk vetenskaplig disciplin, till exempel för att många nuvarande egenskaper förmodligen utvecklats till att fylla andra funktioner än de gör nu. Eftersom det potentiellt kan finnas ett oändligt antal alternativa förklaringar till varför en egenskap har utvecklats, hävdar kritiker att det är omöjligt att fastställa den exakta förklaringen. Även om evolutionärpsykologiska hypoteser är svåra att testa, hävdar evolutionära psykologer att det inte är omöjligt. En del av kritiken av den vetenskapliga basen för evolutionär psykologi inkluderar en kritik av begreppet Environment of Evolutionary Adaptation (EEA). Vissa kritiker hävdar att forskningen vet så lite om den miljö där Homo sapiens utvecklades att det blir mycket spekulativt att förklara specifika egenskaper som en adaption till den mijön. Evolutionspsykologer hävdar att de vet många saker om denna miljö, inklusive fakta om att dagens människors förfäder var jägare-samlare, att de i allmänhet levde i små stammar, etc. Edward Hagen hävdar att människans forntida miljöer inte var radikalt annorlunda på samma sätt som karbon- eller juraperioden och att eran av djur- och växttaxa liknade den moderna världens, liksom geologin och ekologin. Hagen hävdar att få skulle förneka att andra organ utvecklades inom EES (till exempel lungor som utvecklades i en syrerik atmosfär) men kritiker ifrågasätter huruvida hjärnans EEA verkligen är kännbar eller inte, vilket han hävdar utgör selektiv skepsis. Hagen hävdar också att den största delen av den evolutionära psykologiska forskningen baseras på det faktum att kvinnor kan bli gravida och män inte kan det, vilket Hagen observerar också var sant inom EEA.
John Alcock beskriver detta som ”no time machine-argumentet”, eftersom kritiker hävdar att eftersom det inte är möjligt att resa tillbaka i tiden till ESS, så går det inte att avgöra vad som pågick där och därmed vad som vad adaptivt. Alcock hävdar att dagens bevis gör det möjligt för forskare att vara någorlunda säkra på villkoren för EEA och det faktum att så många mänskliga beteenden är adaptiva i den nuvarande miljön är ett bevis för att människors förfäders miljö hade mycket gemensamt med den nuvarande, eftersom dessa beteenden skulle ha utvecklats i våra förfäders miljö. Således drar Alcock slutsatsen att forskare kan göra förutsägelser om egenskapernas adaptiva värde. På liknande sätt hävdar Dominic Murphy att alternativa förklaringar inte bara kan vidarebefordras utan istället behöver sina egna bevis och förutsägelser – om en förklaring gör förutsägelser som de andra inte kan, är det rimligt att lita på den förklaringen. Dessutom hävdar Murphy att andra historiska vetenskaper också gör förutsägelser om moderna fenomen för att komma med förklaringar om tidigare fenomen, till exempel letar kosmologer efter bevis för vad vi skulle förvänta oss att se i nutiden om Big Band var sann, medan geologer gör förutsägelser om moderna fenomen för att avgöra om en asteroid utplånade dinosaurierna. Murphy hävdar att om andra historiska discipliner kan genomföra tester utan en tidsmaskin så måste kritikerna visa varför evolutionär psykologi inte kan testas, eftersom "metoder bör bedömas över hela linjen", inte ifrågasättas i speciella sammanhang.
Modularitet i sinnet
Evolutionspsykologer antar i allmänhet att sinnet, liksom kroppen, består av många utvecklade modulära adaptioner. Även om det finns en viss oenighet inom disciplinen angående graden av generell plasticitet, eller ”allmänhet”, för vissa moduler. Det har föreslagits att modularitet utvecklades eftersom det, jämfört med icke-modulära nätveck, skulle ha gett en fördel i form av fitness och eftersom avslutningskostnaderna är lägre.
Däremot hävdar vissa akademiker att det är onödigt att påstå att det finns högt domänspecifika moduler, och föreslår att hjärnans neurala anatomi stödjer en modell baserad på mer allmänna fakulteter och processer inom området. Dessutom härrör empiriskt stöd för den domänspecifika teorin närstan helt från prestanda på variationer av ”wason selection task” vilket är extremt begränsat i omfattning eftersom den bara testar en subtyp av deduktiva resonemang.
Kulturell snarare än genetisk utveckling av kognitiva verktyg
Psykologen Cecilia Heyes har hävdat att bilden som presenteras av en del evolutionärpsykologi av det mänskliga sinnet som en del samling kognitiva instinkter – tankeorgan formade av genetisk evolution under mycket långa tidsperioder – inte passar forskningsresultat. Hon hävdar istället att människor har kognitiva verktyg – ”tankerogan för speciella ändamål” byggda under utvecklingen genom social interaktion. Liknande kritik artikuleras av Subrena E. Smitch vid University of New Hampshire.
Svar från evolutionära psykologer
Evolutionspsykologer har vänt sig till många av sina kritiker (till exempel i böcker av Segerstråle (2000), Barkow (2005), och Alcock (2001)). Deras motbevisningar bland annat att en del kritik är straw-man argument, baserade på felaktig dikotomi rörande nature vs nurture eller helt enkelt på grundläggande missförstånd av disciplinen.
Robert Kurzban föreslog att (engelsk citat): ”Critics of the field, when they err, are not slightly missing the mark. Their confusion is deep and profound. It´s not like they are marksmen who can´t quite hit the center of the target; they´re holding the gun backwards.”
Det finns flera som har skrivit specifikt för att avhjälpa grundläggande missuppfattningar.
Se även
Arv och miljö
Evolutionsbiologi
Evolutionär utvecklingsbiologi
Humanekologi
Psykologisk nativism
Sociobiologi
Neurologi
Batemans princip
Referenser
Vidare läsning
Buss, D. M. (1995). "Evolutionary psychology: A new paradigm for psychological science". Psychological Inquiry. 6: 1–30. https://doi.org/10.1207%2Fs15327965pli0601_1
Confer, J.C.; Easton, J.A.; Fleischman, D.S.; Goetz, C. D.; Lewis, D.M.G.; Perilloux, C.; Buss, D. M. (2010). "Evolutionary Psychology: Controversies, Questions, Prospects, and Limitations". American Psychologist. 65 (2): 110–26. CiteSeerX 10.1.1.601.8691. https://doi.org/10.1037%2Fa0018413
Cosmides, Leda; Tooby, John (2008). "Evolutionary Psychology". In Hamowy, Ronald (ed.). Evolution Psychology. The Encyclopedia of Libertarianism. Thousand Oaks, CA: SAGE; Cato Institute. pp. 158–61. doi:10.4135/9781412965811.n99. . LCCN 2008009151. OCLC 750831024. https://doi.org/10.4135%2F9781412965811.n99
Heylighen F. (2012). "Evolutionary Psychology", in: A. Michalos (ed.): Encyclopedia of Quality of Life Research (Springer, Berlin).
Kennair, L. E. O. (2002). "Evolutionary psychology: An emerging integrative perspective within the science and practice of psychology". Human Nature Review. 2: 17–61.
Medicus, G. (2005). "Evolutionary Theory of Human Sciences". pp. 9, 10, 11. Retrieved 8 september 2009.http://pcp.vub.ac.be/Papers/EvolutionaryPsychology-QOL.pdf
Gerhard Medicus (2015). Being Human – Bridging the Gap between the Sciences of Body and Mind. Berlin: VWB
Oikkonen, Venla: Gender, Sexuality and Reproduction in Evolutionary Narratives. London: Routledge, 2013.
Delområden inom psykologi
Tvärvetenskap | swedish | 0.497632 |
insects_attracted_to_light/Phototaxis.txt |
Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from a stimulus of light. This is advantageous for phototrophic organisms as they can orient themselves most efficiently to receive light for photosynthesis. Phototaxis is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite.
Two types of positive phototaxis are observed in prokaryotes. The first is called scotophobotaxis (from the word "scotophobia"), which is observed only under a microscope. This occurs when a bacterium swims by chance out of the area illuminated by the microscope. Entering darkness signals the cell to reverse flagella rotation direction and reenter the light. The second type of phototaxis is true phototaxis, which is a directed movement up a gradient to an increasing amount of light. This is analogous to positive chemotaxis except that the attractant is light rather than a chemical.
Phototactic responses are observed in many organisms such as Serratia marcescens, Tetrahymena, and Euglena. Each organism has its own specific biological cause for a phototactic response, many of which are incidental and serve no end purpose.
Phototaxis in bacteria and archea[edit]
Part of a series onMicrobial and microbot movement
Microswimmers
Taxa
Bacterial motility
run-and-tumble
twitching
gliding
Protist locomotion
amoeboids
Taxis
Aerotaxis (oxygen)
Anemotaxis (wind)
Chemotaxis (chemicals)
Electrotaxis(electric current)
Gravitaxis (gravity)
Magnetotaxis (magnetic field)
Phototaxis (light)
Rheotaxis (fluid flow)
Thermotaxis (temperature)
Kinesis
Kinesis
chemokinesis
photokinesis
Microbots and particles
Microbotics
Nanorobotics
Nanomotors
DNA machine
Microparticle
Nanoparticle
Janus particles
Self-propelled particles
Swarm robotics
Biohybrids
Biohybrid microswimmers
bacterial biohybrids
protist biohybrids
robotic sperm
Collective motion
Active matter
Bacteria collective motion
Collective cell migration
Quorum sensing
Swarming motility
Molecular motors
Biological motors
Flagellum
archaellum
cilium
axoneme
motor switch
intraflagellar
evolution
Motor proteins
myosin
kinesin
dynein
Synthetic motors
Synthetic molecular motor
Molecular modelling
Molecular propeller
molecular sensor
molecular shuttle
Molecular tweezers
Related
Brownian motor
Biochip
Endocytosis
Axophilic migration
Cytoskeleton
prokaryotic
eukaryotic
cytoplasmic streaming
Gray goo
Mucilage
Molecular biophysics
Molecular machine
Nanoengineering
Non-motile bacteria
Virophysics
Categoryvte
Phototaxis can be advantageous for phototrophic bacteria as they can orient themselves most efficiently to receive light for photosynthesis. Phototaxis is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite.
Two types of positive phototaxis are observed in prokaryotes (bacteria and archea). The first is called "scotophobotaxis" (from the word "scotophobia"), which is observed only under a microscope. This occurs when a bacterium swims by chance out of the area illuminated by the microscope. Entering darkness signals the cell to reverse flagella rotation direction and reenter the light. The second type of phototaxis is true phototaxis, which is a directed movement up a gradient to an increasing amount of light. This is analogous to positive chemotaxis except that the attractant is light rather than a chemical.
Phototactic responses are observed in a number of bacteria and archae, such as Serratia marcescens. Photoreceptor proteins are light-sensitive proteins involved in the sensing and response to light in a variety of organisms. Some examples are bacteriorhodopsin and bacteriophytochromes in some bacteria. See also: phytochrome and phototropism.
Most prokaryotes (bacteria and archaea) are unable to sense the direction of light, because at such a small scale it is very difficult to make a detector that can distinguish a single light direction. Still, prokaryotes can measure light intensity and move in a light-intensity gradient. Some gliding filamentous prokaryotes can even sense light direction and make directed turns, but their phototactic movement is very slow. Some bacteria and archaea are phototactic.
In most cases the mechanism of phototaxis is a biased random walk, analogous to bacterial chemotaxis. Halophilic archaea, such as Halobacterium salinarum, use sensory rhodopsins (SRs) for phototaxis. Rhodopsins are 7 transmembrane proteins that bind retinal as a chromophore. Light triggers the isomerization of retinal, which leads to phototransductory signalling via a two-component phosphotransfer relay system. Halobacterium salinarum has two SRs, SRI and SRII, which signal via the transducer proteins Htr1 and Htr2 (halobacterial transducers for SRs I and II), respectively. The downstream signalling in phototactic archaebacteria involves CheA, a histidine kinase, which phosphorylates the response regulator, CheY. Phosphorylated CheY induces swimming reversals. The two SRs in Halobacterium have different functions. SRI acts as an attractant receptor for orange light and, through a two-photon reaction, a repellent receptor for near-UV light, while SRII is a repellent receptor for blue light. Depending on which receptor is expressed, if a cell swims up or down a steep light gradient, the probability of flagellar switch will be low. If light intensity is constant or changes in the wrong direction, a switch in the direction of flagellar rotation will reorient the cell in a new, random direction. As the length of the tracks is longer when the cell follows a light gradient, cells will eventually get closer to or further away from the light source. This strategy does not allow orientation along the light vector and only works if a steep light gradient is present (i.e. not in open water).
Some cyanobacteria (e.g. Anabaena, Synechocystis) can slowly orient along a light vector. This orientation occurs in filaments or colonies, but only on surfaces and not in suspension. The filamentous cyanobacterium Synechocystis is capable of both positive and negative two-dimensional phototactic orientation. The positive response is probably mediated by a bacteriophytochrome photoreceptor, TaxD1. This protein has two chromophore-binding GAF domains, which bind biliverdin chromophore, and a C-terminal domain typical for bacterial taxis receptors (MCP signal domain). TaxD1 also has two N-terminal transmembrane segments that anchor the protein to the membrane. The photoreceptor and signalling domains are cytoplasmic and signal via a CheA/CheY-type signal transduction system to regulate motility by type IV pili. TaxD1 is localized at the poles of the rod-shaped cells of Synechococcus elongatus, similarly to MCP containing chemosensory receptors in bacteria and archaea. How the steering of the filaments is achieved is not known. The slow steering of these cyanobacterial filaments is the only light-direction sensing behaviour prokaryotes could evolve owing to the difficulty in detecting light direction at this small scale.
Types of photobehavior found in prokaryotes Top: photophobic and scotophobic responses involving random tumbling or 180° motility reversals induced by sudden changes in the light environment experienced by the cells.Middle: photokinesis involving changes in speed induced by changing light intensity. In patchy light environments, positive photokinesis results in accumulation in low light areas (and vice versa for negative photokinesis).Bottom: true phototaxis results in movement towards or away from a light source, but is not a response to a light gradient. Direction of parallel illumination is indicated by the yellow arrows. Spaces between the filled circles represent equal time intervals.
The ability to link light perception to control of motility is found in a very wide variety of prokaryotes, indicating that this ability must confer a range of physiological advantages. Most directly, the light environment is crucial to phototrophs as their energy source. Phototrophic prokaryotes are extraordinarily diverse, with a likely role for horizontal gene transfer in spreading phototrophy across multiple phyla. Thus, different groups of phototrophic prokaryotes may have little in common apart from their exploitation of light as an energy source, but it should be advantageous for any phototroph to be able to relocate in search of better light environments for photosynthesis. To do this efficiently requires the ability to control motility in response to integrated information on the intensity of light, the spectral quality of light and the physiological status of the cell. A second major reason for light-controlled motility is to avoid light at damaging intensities or wavelengths: this factor is not confined to photosynthetic bacteria since light (especially in the UV region) can be dangerous to all prokaryotes, primarily because of DNA and protein damage and inhibition of the translation machinery by light-generated reactive oxygen species.
Finally, light signals potentially contain rich and complex information about the environment, and the possibility should not be excluded that bacteria make sophisticated use of this information to optimize their location and behavior. For example, plant or animal pathogens could use light information to control their location and interaction with their hosts, and in fact light signals are known to regulate development and virulence in several non-phototrophic prokaryotes. Phototrophs could also benefit from sophisticated information processing, since their optimal environment is defined by a complex combination of factors including light intensity, light quality, day and night cycles, the availability of raw materials and alternative energy sources, other beneficial or harmful physical and chemical factors and sometimes the presence of symbiotic partners. Light quality strongly influences specialized developmental pathways in certain filamentous cyanobacteria, including the development of motile hormogonia and nitrogen-fixing heterocysts. Since hormogonia are important for establishing symbiotic partnerships between cyanobacteria and plants, and heterocysts are essential for nitrogen fixation in those partnerships, it is tempting to speculate that the cyanobacteria may be using light signals as one way to detect the proximity of a plant symbiotic partner. Within a complex and heterogeneous environment such as a phototrophic biofilm, many factors crucial for growth could vary dramatically even within the limited region that a single motile cell could explore. We should therefore expect that prokaryotes living in such environments might control their motility in response to a complex signal transduction network linking a range of environmental cues.
The photophobic response is a change in the direction of motility in response to a relatively sudden increase in illumination: classically, the response is to a temporal change in light intensity, which the bacterium may experience as it moves into a brightly illuminated region. The directional switch may consist of a random selection of a new direction (‘tumbling’) or it may be a simple reversal in the direction of motility. Either has the effect of repelling cells from a patch of unfavorable light. Photophobic responses have been observed in prokaryotes as diverse as Escherichia coli, purple photosynthetic bacteria and haloarchaea.
The scotophobic (fear of darkness) response is the converse of the photophobic response described above: a change in direction (tumbling or reversal) is induced when the cell experiences a relatively sudden drop in light intensity. Photophobic and scotophobic responses both cause cells to accumulate in regions of specific (presumably favorable) light intensity and spectral quality. Scotophobic responses have been well documented in purple photosynthetic bacteria, starting with the classic observations of Engelmann in 1883, and in cyanobacteria. Scotophobic/photophobic responses in flagellated bacteria closely resemble the classic ‘biased random walk’ mode of bacterial chemotaxis, which links perception of temporal changes in the concentration of a chemical attractant or repellent to the frequency of tumbling. The only significant distinction is that the scotophobic/photophobic responses involve perception of temporal changes in light intensity rather than the concentration of a chemical.
Photokinesis is a light-induced change in the speed (but not direction) of movement. Photokinesis may be negative (light-induced reduction of motility) or positive (light-induced stimulation of motility). Photokinesis can cause cells to accumulate in regions of favorable illumination: they linger in such regions or accelerate out of regions of unfavorable illumination. Photokinesis has been documented in cyanobacteria and purple photosynthetic bacteria.
True phototaxis consists of directional movement which may be either towards a light source (positive phototaxis) or away from a light source (negative phototaxis). In contrast to the photophobic/scotophobic responses, true phototaxis is not a response to a temporal change in light intensity. Generally, it seems to involve direct sensing of the direction of illumination rather than a spatial gradient of light intensity. True phototaxis in prokaryotes is sometimes combined with social motility, which involves the concerted movement of an entire colony of cells towards or away from the light source. This phenomenon could also be described as community phototaxis. True phototaxis is widespread in eukaryotic green algae, but among the prokaryotes it has been documented only in cyanobacteria, and in social motility of colonies of the purple photosynthetic bacterium Rhodocista centenaria.
Phototaxis in protists[edit]
Diversity of phototactic protists (a) green alga (b) heterokont zoospore (c) cryptomonad alga(d) dinoflagellate (e) Euglena
See also: Eyespot apparatus
Phototactic movements in the green algae Volvox rousseletii (a) Straight-ahead swimming in the dark(b) A sudden dark-light switch causes the flagellar beating to reverse in the anterior hemisphere and the deceleration of the spheroid's forward movement (photophobic response)(c) After approximately 2 seconds, only cells on the illuminated side of the anterior hemisphere of the rotating spheroid show the reversed flagellar beating direction, resulting in an acceleration of the spheroid's forward movement and turning toward the light source. Gravity assists the phototactic movements because it pulls more on the posterior hemisphere due to an anisotropic mass distribution caused by the denser daughter spheroids within the posterior hemisphere and probably also by the closer spacing of the somatic cells in the posterior hemisphere
Some protists (unicellular eukaryotes) can also move toward or away from light, by coupling their locomotion strategy with a light-sensing organ. Eukaryotes evolved for the first time in the history of life the ability to follow light direction in three dimensions in open water. The strategy of eukaryotic sensory integration, sensory processing and the speed and mechanics of tactic responses is fundamentally different from that found in prokaryotes.
Both single-celled and multi-cellular eukaryotic phototactic organisms have a fixed shape, are polarized, swim in a spiral and use cilia for swimming and phototactic steering. Signalling can happen via direct light-triggered ion currents, adenylyl cyclases or trimeric G-proteins. The photoreceptors used can also be very different (see below). However, signalling in all cases eventually modifies the beating activity of cilia. The mechanics of phototactic orientation is analogous in all eukaryotes. A photosensor with a restricted view angle rotates to scan the space and signals periodically to the cilia to alter their beating, which will change the direction of the helical swimming trajectory. Three-dimensional phototaxis can be found in five out of the six eukaryotic major groups (opisthokonts, Amoebozoa, plants, chromalveolates, excavates, rhizaria).
Pelagic phototaxis is present in green algae – it is not present in glaucophyte algae or red algae. Green algae have a "stigma" located in the outermost portion of the chloroplast, directly underneath the two chloroplast membranes. The stigma is made of tens to several hundreds of lipid globules, which often form hexagonal arrays and can be arranged in one or more rows. The lipid globules contain a complex mixture of carotenoid pigments, which provide the screening function and the orange-red colour, as well as proteins that stabilize the globules. The stigma is located laterally, in a fixed plane relative to the cilia, but not directly adjacent to the basal bodies. The fixed position is ensured by the attachment of the chloroplast to one of the ciliary roots. The pigmented stigma is not to be confused with the photoreceptor. The stigma only provides directional shading for the adjacent membrane-inserted photoreceptors (the term "eyespot" is therefore misleading). Stigmata can also reflect and focus light like a concave mirror, thereby enhancing sensitivity.
In the best-studied green alga, Chlamydomonas reinhardtii, phototaxis is mediated by a rhodopsin pigment, as first demonstrated by the restoration of normal photobehaviour in a blind mutant by analogues of the retinal chromophore. Two archaebacterial-type rhodopsins, channelrhodopsin-1 and -2, were identified as phototaxis receptors in Chlamydomonas. Both proteins have an N-terminal 7-transmembrane portion, similar to archaebacterial rhodopsins, followed by an approximately 400 residue C-terminal membrane-associated portion. CSRA and CSRB act as light-gated cation channels and trigger depolarizing photocurrents. CSRA was shown to localize to the stigma region using immunofluorescence analysis (Suzuki et al. 2003). Individual RNAi depletion of both CSRA and CSRB modified the light-induced currents and revealed that CSRA mediates a fast, high-saturating current while CSRB a slow, low-saturating one. Both currents are able to trigger photophobic responses and can have a role in phototaxis, although the exact contribution of the two receptors is not yet clear.
As in all bikonts (plants, chromalveolates, excavates, rhizaria), green algae have two cilia, which are not identical. The anterior cilium is always younger than the posterior one. In every cell cycle, one daughter cell receives the anterior cilium and transforms it into a posterior one. The other daughter inherits the posterior, mature cilium. Both daughters then grow a new anterior cilium.
As all other ciliary swimmers, green algae always swim in a spiral. The handedness of the spiral is robust and is guaranteed by the chirality of the cilia. The two cilia of green algae have different beat patterns and functions. In Chlamydomonas, the phototransduction cascade alters the stroke pattern and beating speed of the two cilia differentially in a complex pattern. This results in the reorientation of the helical swimming trajectory as long as the helical swimming axis is not aligned with the light vector.
Phototaxis in invertebrates[edit]
Jellyfish[edit]
Positive and negative phototaxis can be found in several species of jellyfish such as those from the genus Polyorchis. Jellyfish use ocelli to detect the presence and absence of light, which is then translated into anti-predatory behaviour in the case of a shadow being cast over the ocelli, or feeding behaviour in the case of the presence of light. Many tropical jellyfish have a symbiotic relationship with photosynthetic zooxanthellae that they harbor within their cells. The zooxanthellae nourish the jellyfish, while the jellyfish protects them, and moves them toward light sources such as the sun to maximize their light-exposure for efficient photosynthesis. In a shadow, the jellyfish can either remain still, or quickly move away in bursts to avoid predation and also re-adjust toward a new light source.
This motor response to light and absence of light is facilitated by a chemical response from the ocelli, which results in a motor response causing the organism to swim toward a light source.
Marine ragworm[edit]
Phototaxis and UV-avoidance of Platynereis dumerilii larvae responding to UV-light (380 nm) from above See text body for further explanation.
Phototaxis has been well studied in the marine ragworm Platynereis dumerilii. Both Platynereis dumerilii trochophore and its metatrochophore larvae are positively phototactic. Phototaxis is mediated by simple eyespots that consists of a pigment cell and a photoreceptor cell. The photoreceptor cell synapses directly onto ciliated cells, which are used for swimming. The eyespots do not give spatial resolution, therefore the larvae are rotating to scan their environment for the direction where the light is coming from.
Platynereis dumerilii larvae (nectochaete) can switch between positive and negative phototaxis. Phototaxis there is mediated by two pairs of more complex pigment cup eyes. These eyes contain more photoreceptor cells that are shaded by pigment cells forming a cup. The photoreceptor cells do not synapse directly onto ciliated cells or muscle cells but onto inter-neurons of a processing center. This way the information of all four eye cups can be compared and a low-resolution image of four pixels can be created telling the larvae where the light is coming from. This way the larva does not need to scan its environment by rotating. This is an adaption for living on the bottom of the sea the lifestyle of the larva while scanning rotation is more suited for living in the open water column, the lifestyle of the trochophore larva. Phototaxis in the Platynereis dumerilii larva has a broad spectral range which is at least covered by three opsins that are expressed by the cup eyes: Two rhabdomeric opsins and a Go-opsin.
Platynereis dumerilii
However, not every behavior that looks like phototaxis is phototaxis: Platynereis dumerilii nechtochate and metatrochophore larvae swim up first when they are stimulated with UV-light from above. But after a while, they change the direction and avoid the UV-light by swimming down. This looks like a change from positive to negative phototaxis (see video left), but the larvae also swim down if UV-light comes non-directionally from the side. And so they do not swim to or away from the light, but swim down, this means to the center of gravity. Thus this is a UV-induced positive gravitaxis. Positive phototaxis (swimming to the light from the surface) and positive gravitaxis (swimming to the center of gravity) are induced by different ranges of wavelengths and cancel out each other at a certain ratio of wavelengths. Since the wavelengths compositions change in water with depth: Short (UV, violet) and long (red) wavelengths are lost first, phototaxis and gravitaxis form a ratio-chromatic depth gauge, which allows the larvae to determine their depth by the color of the surrounding water. This has the advantage over a brightness based depth gauge that the color stays almost constant independent of the time of the day or whether it is cloudy.
In the diagram on the right, the larvae start swimming upwards when UV-light switched on (marked by the violet square). But later, they are swimming downward. The larval tracks are color coded: Red for upward and blue for downward swimming larvae. The video runs at double speed.
Phototaxis of Platynereis dumerilii larvae: Some larvae show positive phototaxis by swimming towards the light. Other larvae show negative phototaxis by swimming away from the light. First, the light comes from left and then from the right side. When the light direction is switched the larvae turn. The side where the light is coming from is indicated by a white bar. The larvae display mixed phototaxis, some negatively phototactic larvae are tracked. The scale bar represents 2 mm.
Phototaxis of Platynereis dumerilii larvae: The larvae turn when the light coming from the left is switched on. While the larvae turn they bend their body with their longitudinal muscles. The larvae show two dots on the head, which are the shading pigment of their adult cup eyes that mediate phototaxis. The direction where the light is coming from is indicated by white bars.
Insects[edit]
Moths are positively phototactic
Positive phototaxis can be found in many flying insects such as moths, grasshoppers, and flies. Drosophila melanogaster has been studied extensively for its innate positive phototactic response to light sources, using controlled experiments to help understand the connection between airborne locomotion toward a light source. This innate response is common among insects that fly primarily during the night utilizing transverse orientation vis-à-vis the light of the moon for orientation. Artificial lighting in cities and populated areas results in a more pronounced positive response compared to that with the distant light of the moon, resulting in the organism repeatedly responding to this new supernormal stimulus and innately flying toward it.
Evidence for the innate response of positive phototaxis in Drosophila melanogaster was carried out by altering the wings of several individual specimens, both physically (via removal) and genetically (via mutation). In both cases there was a noticeable lack of positive phototaxis, demonstrating that flying toward light sources is an innate response to the organisms' photoreceptors receiving a positive response.
Negative phototaxis can be observed in larval drosophila melanogaster within the first three developmental instar stages, despite adult insects displaying positive phototaxis. This behaviour is common among other species of insects which possess a flightless larval and adult stage in their life cycles, only switching to positive phototaxis when searching for pupation sites. Tenebrio molitor by comparison is one species which carries its negative phototaxis into adulthood.
Relation to magnetic fields[edit]
Under experimental conditions, organisms that use positive phototaxis have also shown a correlation with light and magnetic fields. Under homogeneous light conditions with a shifting magnetic field, Drosophila melanogaster larvae reorient themselves toward predicted directions of greater or lesser light intensities as expected by a rotating magnetic field. In complete darkness, the larvae orient randomly without any notable preference. This suggests the larvae can observe a visible pattern in combination with light.
See also[edit]
Wikimedia Commons has media related to Phototaxis.
Photokinesis
Phototropism (more relevant to plants and fungi) | biology | 24270 | https://da.wikipedia.org/wiki/Fotonisk%20krystal | Fotonisk krystal | Fotoniske krystaller er metamaterialer, der udgøres af periodiske dielektriske eller metal-dielektriske (nano)strukturer som er designet til at påvirke elektromagnetiske bølgers (EM) udbredelse på den samme måde som det periodiske potential i et halvledende krystal påvirker elektronernes bevægelse ved at definere tilladte og forbudte elektriske energibånd.
Fraværet af tilladte udbredelsesenergibånd indeni strukturen for et interval af bølgelængder kaldes et fotonisk båndgab, som forårsager bemærkelsesværdige optiske fænomener, som bl.a. resulterer i; spontan udsendelse, generering af alle regnbuens farver ud fra infrarødt-lys, højreflekterende spejle som virker i alle retninger og lysleder med lavt tab, og materialer med negativt brydningsindeks.
Fotonisk krystal er grundlæggende set baseret på det fysiske fænomen diffraktion.
Kilder/referencer
Se også
Kvantemekanik
Optik
Nanoteknologi
Kvanteø
Opal
Eksterne henvisninger
Webarchive backup: Ingeniøren nr. -3/1999: Dansk gennembrud i fiberoptik Danske og engelske forskere har sammen bevist, at optisk fiber med huller i kan transportere lys over lange afstande.
Vejviser: Photonic Crystal and Photonic Band Gap Links
Cnet, August 31, 2000, Why photonics? Citat: "...Demand for photonic equipment is skyrocketing. Internet traffic on the backbone networks has been doubling every three months and shows no sign of abating. Companies are laying fiber in just about every cross-country right-of-way they can find. First it was along the railways, and now it's the gas pipelines, sewers and just about any conduit you can think of... "
November 3, 2000, Sandia LabNews: Cheesecloth-like photonics device bends light with little loss Citat: "...the cheesecloth-like structure can be considered essentially a wire for light...Because of the very small light loss, the technique offers the potential of ultimately replacing electronic chips with faster, cooler photonic chips...two-dimensional crystals are cheaper and far easier to build..."
Number 646 #1, July 16, 2003, AIP: Photonic Crystal Shifts Energy Citat: "...Shawn Lin and his Sandia colleagues, in the course of their studies of photonic crystals, have seemed to challenge the venerable formulation, made by Max Planck a hundred years ago, of what kind of emission spectrum a body should have..."
CERN Courier: Photonic crystal makes flat lens Citat: "...The key to creating the flat lens lies with the recent advent of materials – photonic crystals – that effectively have a negative index of refraction...the principle could herald a revolution in optics..."
BBC News: 3 January, 2001, Sea mouse promises bright future Citat: "...The sea mouse, or Aphrodita, has spines that normally appear deep red in colour. But when light falls on a spine perpendicular to its axis, stripes of different colours appear – strong blues and greens..."The simple structure responsible for this effect is a remarkable example of photonic engineering by a living organism."..."These structures may have application in photonic communications, where there is much interest in fabricating photonic crystal fibres with similar morphology."..."
Metamaterialer
Fotonik | danish | 0.653631 |
insects_attracted_to_light/Entomology.txt | Entomology (from Ancient Greek ἔντομον (entomon) 'insect', and -λογία (-logia) 'study') is the scientific study of insects, a branch of zoology. In the past the term insect was less specific, and historically the definition of entomology would also include the study of animals in other arthropod groups, such as arachnids, myriapods, and crustaceans. This wider meaning may still be encountered in informal use.
Like several of the other fields that are categorized within zoology, entomology is a taxon-based category; any form of scientific study in which there is a focus on insect-related inquiries is, by definition, entomology. Entomology, therefore, overlaps with a cross-section of topics as diverse as molecular genetics, behavior, neuroscience, biomechanics, biochemistry, systematics, physiology, developmental biology, ecology, morphology, and paleontology.
Over 1.3 million insect species have been described, more than two-thirds of all known species. Some insect species date back to around 400 million years ago. They have many kinds of interactions with humans and other forms of life on Earth.
History[edit]
For a chronological guide, see Timeline of entomology.
Plate from Transactions of the Entomological Society, 1848
These 100 Trigonopterus species were described simultaneously using DNA barcoding.
Entomology is rooted in nearly all human cultures from prehistoric times, primarily in the context of agriculture (especially biological control and beekeeping). The natural philosopher Pliny the Elder (23–79 CE) wrote a book on the kinds of insects, while the scientist of Kufa, Ibn al-A'rābī (760–845 CE) wrote a book on flies, Kitāb al-Dabāb (كتاب الذباب). However scientific study in the modern sense began only relatively recently, in the 16th century. Ulisse Aldrovandi's De Animalibus Insectis (Concerning Insect Animals) was published in 1602. Microscopist Jan Swammerdam published History of Insects, correctly describing the reproductive organs of insects and metamorphosis. In 1705, Maria Sibylla Merian published the book Metamorphosis Insectorum Surinamensium about the tropical insects of Dutch Surinam.
Early entomological works associated with the naming and classification of species followed the practice of maintaining cabinets of curiosity, predominantly in Europe. This collecting fashion led to the formation of natural history societies, exhibitions of private collections, and journals for recording communications and the documentation of new species. Many of the collectors tended to be from the aristocracy, and there developed a trade involving collectors around the world and traders. This has been called the "era of heroic entomology." William Kirby is widely considered as the father of entomology in England. In collaboration with William Spence, he published a definitive entomological encyclopedia, Introduction to Entomology, regarded as the subject's foundational text. He also helped found the Royal Entomological Society in London in 1833, one of the earliest such societies in the world; earlier antecedents, such as the Aurelian society date back to the 1740s. In the late 19th century, the growth of agriculture, and colonial trade spawned the "era of economic entomology" which created the professional entomologist associated with the rise of the university and training in the field of biology.
Entomology developed rapidly in the 19th and 20th centuries and was studied by large numbers of people, including such notable figures as Charles Darwin, Jean-Henri Fabre, Vladimir Nabokov, Karl von Frisch (winner of the 1973 Nobel Prize in Physiology or Medicine), and twice Pulitzer Prize winner E. O. Wilson.
There has also been a history of people becoming entomologists through museum curation and research assistance, such as Sophie Lutterlough at the Smithsonian National Museum of Natural History. Insect identification is an increasingly common hobby, with butterflies and dragonflies being the most popular.
Most insects can easily be allocated to order, such as Hymenoptera (bees, wasps, and ants) or Coleoptera (beetles). However, identifying to genus or species is usually only possible through the use of identification keys and monographs. Because the class Insecta contains a very large number of species (over 330,000 species of beetles alone) and the characteristics distinguishing them are unfamiliar, and often subtle (or invisible without a microscope), this is often very difficult even for a specialist. This has led to the development of automated species identification systems targeted on insects, for example, Daisy, ABIS, SPIDA and Draw-wing.
In pest control[edit]
In 1994, the Entomological Society of America launched a new professional certification program for the pest control industry called the Associate Certified Entomologist (ACE). To qualify as a "true entomologist" an individual would normally require an advanced degree, with most entomologists pursuing a PhD. While not true entomologists in the traditional sense, individuals who attain the ACE certification may be referred to as ACEs or Associate Certified Entomologists.
As such, there are also other credential programs managed by the Entomological Society of America, that have varying credential requirements. These other programs, are known as Public Health Entomology (PHE), Certified IPM Technicians (CITs), and Board Certified Entomologists (BCEs) (ESA Certification Corporation). To be qualified in Public Health Entomology (PHE), one must succeed in passing an exam, that refers to the types of arthropods that have the capability, of being able to spread diseases and lead to medical complications (ESA Certification Corporation). Along with this, these individuals also have to "agree to ascribe to a code of ethical behavior" (ESA Certification Corporation). Individuals who are planning to become Certified IPM Technicians (CITs), need to obtain at around 1-4 years of experience in pest management and successfully pass an exam, that is based on the information, that they are acquainted with (ESA Certification Corporation). Like in Public Health Entomology (PHE), those who want to become Certified IPM Technicians (CITs), also have to "agree to ascribe to a code of ethical behavior" (ESA Certification Corporation). Additionally, these individuals have to be approved on being able to use pesticides (ESA Certification Corporation). In respects to those, who plan on becoming Board Certified Entomologists (BCEs), these individuals have to pass two exams and "agree to ascribe to a code of ethical behavior" (ESA Certification Corporation). As with this, they also have to fulfill a certain amount of educational requirements, every 12 months (ESA Certification Corporation).
Subdisciplines[edit]
Example of a collection barcode on a pinned beetle specimen
Many entomologists specialize in a single order or even a family of insects, and a number of these subspecialties are given their own informal names, typically (but not always) derived from the scientific name of the group:
Coleopterology – beetles
Dipterology – flies
Odonatology – dragonflies and damselflies
Hemipterology – true bugs
Isopterology – termites
Lepidopterology – moths and butterflies
Melittology (or Apiology) – bees
Myrmecology – ants
Orthopterology – grasshoppers, crickets, etc.
Trichopterology – caddisflies
Vespology – social wasps
Entomologists[edit]
Main article: List of entomologists
"The butterfly catcher", painting by Carl Spitzweg
Organizations[edit]
Like other scientific specialties, entomologists have a number of local, national, and international organizations. There are also many organizations specializing in specific subareas.
Amateur Entomologists' Society
Entomological Society of America
Entomological Society of Canada
Entomological Society of Japan
Entomologischer Verein Krefeld
Entomological Society of India
International Union for the Study of Social Insects
Netherlands Entomological Society
Royal Belgian Entomological Society
Royal Entomological Society of London
Russian Entomological Society
Senckenberg Deutsches Entomologisches Institut
Société entomologique de France
Australian Entomological Society
Entomological Society of New Zealand
Research collection[edit]
Here is a list of selected very large insect collections, housed in museums, universities, or research institutes.
Asia[edit]
Zoological Survey of India
Insect Museum, Tamil Nadu Agricultural University, Coimbatore, Tamil Nadu, India
National Pusa Collection, Division of Entomology, Indian Agricultural Research Institute, New Delhi, India
Pakistan Museum of Natural History Garden Avenue, Shakarparian, Islamabad, Pakistan
Museum Zoologicum Bogoriense, Indonesia
Africa[edit]
Natal Museum, Pietermaritzburg, South Africa
Australasia[edit]
The Entomology Research Collection at Lincoln University, New Zealand, with curator John Marris
Lincoln University Entomology Research Collection, Lincoln, New Zealand
Museum of New Zealand Te Papa Tongarewa, Wellington, New Zealand
New Zealand Arthropod Collection, Landcare Research Manaaki Whenua, Auckland, New Zealand
Europe[edit]
Bavarian State Collection of Zoology, Zoologische Staatssammlung München
Museu de Ciències Naturals de Barcelona, Barcelona, Spain
Muséum national d'histoire naturelle, Paris, France
Museum für Naturkunde, Berlin, Germany
Kelvingrove Art Gallery, Glasgow, Scotland
Natural History Museum, Budapest Hungarian Natural History Museum
Natural History Museum, Geneva
Natural History Museum, Leiden, the Netherlands
Natural History Museum, London, United Kingdom
Natural History Museum, Oslo Norway
Natural History Museum, St. Petersburg Zoological Collection of the Russian Academy of Science
Naturhistorisches Museum, Vienna, Austria
Oxford University Museum of Natural History, Oxford
Royal Museum for Central Africa, Brussels, Belgium
Swedish Museum of Natural History, Stockholm, Sweden
World Museum Liverpool, the Bug House
United States[edit]
Academy of Natural Sciences of Philadelphia
American Museum of Natural History, New York City
Auburn University Museum of Natural History, Auburn, Alabama
Audubon Insectarium, New Orleans
Bohart Museum of Entomology, Davis, California
California Academy of Sciences, San Francisco
Carnegie Museum of Natural History, Pittsburgh
Cleveland Museum of Natural History, Cleveland
Entomology Research Museum, University of California, Riverside
Essig Museum of Entomology, Berkeley, California
Field Museum of Natural History, Chicago
Florida Museum of Natural History, University of Florida, Gainesville, Florida
Illinois Natural History Survey, Champaign, Illinois
J. Gordon Edwards Museum, San Jose, California
Museum of Comparative Zoology, Cambridge, Massachusetts
Natural History Museum of Los Angeles County, Los Angeles
National Museum of Natural History, Washington, D.C.
New Mexico State University Arthropod Museum
North Carolina State University Insect Museum, Raleigh, North Carolina
Peabody Museum of Natural History, New Haven, Connecticut
San Diego Natural History Museum, San Diego, California
The National Museum of Play, Rochester, New York
Texas A&M University, College Station, Texas
University of Minnesota, St. Paul campus (UMSP), Minnesota
University of Kansas Natural History Museum, Lawrence, Kansas
University of Nebraska State Museum, Lincoln, Nebraska
University of Missouri Enns Entomology Museum, University of Missouri, Columbia, Missouri
Canada[edit]
Canadian Museum of Nature, Ottawa, Ontario
Canadian National Collection of Insects, Arachnids and Nematodes, Ottawa, Ontario
E.H. Strickland Entomological Museum, University of Alberta, Edmonton, Alberta
Lyman Entomological Museum, Macdonald Campus of McGill University, Sainte-Anne-de-Bellevue, Quebec
Montreal Insectarium, Montreal, Quebec
Newfoundland Insectarium, Reidville, Newfoundland and Labrador
Royal Alberta Museum, Edmonton, Alberta
Royal Ontario Museum, Toronto, Ontario
University of Guelph Insect Collection, Guelph, Ontario
Victoria Bug Zoo, Victoria, British Columbia
J. B. Wallis / R. E. Roughley Museum of Entomology, Winnipeg, Manitoba
See also[edit]
Biology portalInsects portal
Arachnology
Carcinology
Cultural entomology
Ethnoentomology
Forensic entomology
Forensic entomologist
Forensic entomology and the law
Insect thermoregulation
Insects on stamps
List of entomological journals
Medical entomology
Myriapodology
Timeline of entomology – 1800–1850
Timeline of entomology – 1850–1900
Timeline of entomology since 1900 | biology | 1238240 | https://sv.wikipedia.org/wiki/Thomas%20Nuttall | Thomas Nuttall | Thomas Nuttall, född 5 januari 1786 i Long Preston vid Settle i Yorkshire, död 10 september 1859 i Nutgrove vid Rainhill i Lancashire, var en engelsk botaniker och zoolog. Han var pionjär inom botanisk utforskning av okända trakter i USA.
Biografi
Nuttall började i unga år som lärling i tryckeri, troligen i Liverpool, där han hade släktingar i samma bransch. Sökte sedan olönsamt arbete i London; hade ständigt ekonomiska bekymmer. Utvandrade därför 1808 till USA för att söka bättre lycka där. Fartyget Halcyon, där han var passagerare, landsatte honom i Philadelphia, där han stannade till 1810.
Genom självstudier hade han skaffat sig vissa kunskaper i latin och grekiska. Till en början var hans intresse riktat åt mineralogi. Kunskaper och intresse i detta ämne framskymtar i några av hans senare insamlingsresor, som utöver mängder av växter, även omfattade några mineralprover.
I Philadelphia blev han bekant med botanikern Benjamin Smith Barton som föreslog honom att studera botanik och bli växtsamlare. Nuttall slog till.
1810 till 1812 gjorde han insamlingsexkursioner från St Louis och genom Missouri, för att under perioden 1812 – 1815 vara i England. 1815 – 1818 var han huvudsakligen verksam i Philadelphia. Han blev fellow i London Linnean Society. 1817 belv han invald i American Philosophical Society och korresponderande medlem i Philadelphia Academy of Natural Sciences. Under 1818 – 1820 gjorde han resor i Arkansas i områden aldrig tidigare blivit i vetenskapliga ärenden besökta, men hävdade av indianstammar. 1821 – 1822 tillbringade han i Philadelphia och engagerades 1822 vid Harvard University i Cambridge, Massachusetts för att fylla en professurvakans. Emellertid fanns inte tillräckliga medel för att finansiera en professortjänst, så Nuttall utnämndes i stället till Curator of the Botanic Garden. Under denna tid gav han bara få föreläsningar för studenterna, och ägnade sig mest åt att odla sällsynta växter samt studera mineralogi och ornitologi. Tiden 1823 – 1833 tillbringade han i Cambridge, Massachusetts för att 1833 åter vara i Philadelphia. 1834 – 1836 gjorde han resor i fjärran väst och Cape Horn, Kanada och 1835 besökte han Sandwichöarna, samlade växter och snäckor. Därefter tog sig Nuttall till Boston. 1836 – 1841 var han åter i Philadelphiaoch arbetade vid Academy of Natural Sciences
1841 återvände han till England för att ta den genom testamente ärvda egendomen Nutgrove i närheten av Liverpool i besittning. I testamentet fanns ett villkor att Nuttall måste vistas där i minst 9 månader om året. Nuttall var tveksam inför detta, ty han hade fortfarande intressen kvar i Philadelphia. Genom att slå ihop tre månader i slutet av 1847 med tre månader i början av 1848 kunde Nuttall i alla fall verka ett halvår i Philadelphia. Därefter vistades han i England till sin död.
Trots att det europeiska fastlandet låg så nära, besökte han det aldrig.
Eponym
Nuttallia Raf., 1817
Nuttallae Raf., 1818
Nuttallia Spreng., 1820
Nuttallia W.P.C.Barton, 1822
Nuttallia Torr., 1828
Nuttallia Torr. & Gray ex Hook. & Arn., 1838
Nuttallia cerasiformis Torr. & Gray, 1839
Bibliografi
1813 A catalogue of new and interesting plants collected in Upper Lousiana, principally on the River Missouri
1817 Observations on the genus Eriogenum, and order Polygonaceae
1817 An account of two new genera of Plants; of a species of Tillea, and another of Limosella, recently discovered on the banks of the Delaware in the vicinity of Philadelphia
1817 Description of Collisia, a new genus of plants med dedikation till Z. Collins
1818 The genera of North American plants and catalogue of the species, to the year of 1817, två band (Faksimilutgåva 1971)
1821 Journey into the Interior of Arkansas in 1818 and 1819 with occasional observations on the manners of the aboriginers
Appendix (1) An account of the ancient aboriginal Population of the Banks of the Mississippi
Appendix (2) A History of the Natches
Appendix (3) Observations on the Chickasawas and Choctaws
Appendix (4) Meteorological Observations
1820 – 1822
A geographical Description of the Valley of the Mississippi
Description of the rare Plants recently introduced into the Gardens of Philadelphia
Observations on the genus Orysopsis
Remarks on the Species of Corallorhiza indigenous to the United States
On the Serpentine Rocks of Hoboken, and the Minerals which they contain
1825 Description of two new genera of the natural order Crociferae
1827 utgåva 1: An introduktion to systematic and physiological botany. 360 sidor, 12 litografier
1830 Utgåva 2: An introduktion to systematic and physiological botany. jämte tillägg, 363 sidor, 12 litografier
1832 Manual of the Ornithology of the United States and Canada. 2 band om vardera ca 600 sidor, illustrerade med utomordentliga träsnitt
Ca 1832
Introduction to Systematic and Physiological Botany
A Catalogue of Plants from Florida
Remarks on the Minerals of Paterson and Sparta, New Jersey
Reply to Mr. Seybert
Remarks and Inquiries concerning the Birds of Massachusetts
A Description of a new Species of Sarracenia
An account of the Jalap Plant as an Ipomæa Ca 1833 A Catalogue of Plants collected chiefly in the Valleys
1834 A catalogue of Plants collected chiefly in the Valleys of the Rocky Mountains towards the sources of the Columbia River, by Mr. Nathaniel B. Wyeth, and described by T. Nuttall 1834 Descriptions of some the Rarer Plants indigenous to the United States
1835 Collections towards a flora of the Territory of Arkansas
1840 New genera and species of plants 1840 Description of new species and genera of plants in the natural order of the Composite, collected on a tour across the continent to the Pacific, a residence in Oregon, and a visit to the Sandwich Islands and Upper California during the years 1834 and 1835
1842 Description and notices of new and rare plants in the natural orders of Lobeliaceae, Campanulaceae, Vaccineae and Ericaceæ collected in a journey across the Continent of North America, and during a visit to the Sandwich Islands and Upper California
1842 – 1846 The North American sylva
1849 Description of plants collected by Mr. William Gambel in the Rocky Mountains and Upper California
1853 Descriptions and observations on some species of Rhododendron, collected in Assam and Bootan by Thomas J. Booth''
Källor
Brittiska botaniker
Brittiska zoologer
Engelska forskare
Födda 1786
Avlidna 1859
Män
Personer från Yorkshire
Ledamöter av American Philosophical Society
Autodidakter
Personer verksamma vid Harvard University | swedish | 0.526402 |
insects_attracted_to_light/Insect.txt |
Insects (from Latin insectum) are hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of jointed legs, compound eyes, and a pair of antennae. Insects are the most diverse group of animals, with more than a million described species; they represent more than half of all animal species.
The insect nervous system consists of a brain and a ventral nerve cord. Most insects reproduce by laying eggs. Insects breathe air through a system of paired openings along their sides, connected to small tubes that take air directly to the tissues. The blood therefore does not carry oxygen; it is only partly contained in vessels, and some circulates in an open hemocoel. Insect vision is mainly through their compound eyes, with additional small ocelli. Many insects can hear, using tympanal organs, which may be on the legs or other parts of the body. Their sense of smell is via receptors, usually on the antennae and the mouthparts.
Nearly all insects hatch from eggs. Insect growth is constrained by the inelastic exoskeleton, so development involves a series of molts. The immature stages often differ from the adults in structure, habit and habitat. Groups that undergo four-stage metamorphosis often have a nearly immobile pupa. Insects that undergo three-stage metamorphosis lack a pupa, developing through a series of increasingly adult-like nymphal stages. The higher level relationship of the insects is unclear. Fossilized insects of enormous size have been found from the Paleozoic Era, including giant dragonfly-like insects with wingspans of 55 to 70 cm (22 to 28 in). The most diverse insect groups appear to have coevolved with flowering plants.
Adult insects typically move about by walking and flying; some can swim. Insects are the only invertebrates that can achieve sustained powered flight; insect flight evolved just once. Many insects are at least partly aquatic, and have larvae with gills; in some species, the adults too are aquatic. Some species, such as water striders, can walk on the surface of water. Insects are mostly solitary, but some, such as bees, ants and termites, are social and live in large, well-organized colonies. Others, such as earwigs, provide maternal care, guarding their eggs and young. Insects can communicate with each other in a variety of ways. Male moths can sense the pheromones of female moths over great distances. Other species communicate with sounds: crickets stridulate, or rub their wings together, to attract a mate and repel other males. Lampyrid beetles communicate with light.
Humans regard many insects as pests, especially those that damage crops, and attempt to control them using insecticides and other techniques. Others are parasitic, and may act as vectors of diseases. Insect pollinators are essential to the reproduction of many flowering plants and so to their ecosystems. Many insects are ecologically beneficial as predators of pest insects, while a few provide direct economic benefit. Two species in particular are economically important and were domesticated many centuries ago: silkworms for silk and honey bees for honey. Insects are consumed as food in 80% of the world's nations, by people in roughly 3000 ethnic groups. Human activities are having serious effects on insect biodiversity.
Etymology
The word insect comes from the Latin word inseco, from in, "to cut up", as insects appear to be cut into three parts. The Latin word was introduced by Pliny the Elder who calqued the Ancient Greek word ἔντομον éntomon "insect" (as in entomology) from ἔντομος éntomos "cut in pieces"; this was Aristotle's term for this class of life in his biology, also in reference to their notched bodies. The English word insect first appears in 1601 in Philemon Holland's translation of Pliny.
Insects and other bugs
Distinguishing features
In common speech, insects and other terrestrial arthropods are often called bugs. Entomologists to some extent reserve the name "bugs" for a narrow category of "true bugs", insects of the order Hemiptera, such as cicadas and shield bugs. Other terrestrial arthropods, such as centipedes, millipedes, woodlice, spiders, mites and scorpions, are sometimes confused with insects, since they have a jointed exoskeleton. Adult insects are the only arthropods that ever have wings, with up to two pairs on the thorax. Whether winged or not, adult insects can be distinguished by their three-part body plan, with head, thorax, and abdomen; they have three pairs of legs on the thorax.
Insects and other bugs that could be confused with them
Insect: Six legs, three-part body(head, thorax, abdomen),up to two pairs of wings
Spider: eight legs,two-part body
Woodlouse: seven pairs of legs, seven body segments (plus head and tail)
Centipede: many legs,one pair per segment
Millipede: many legs,two pairs per segment
Diversity
Main article: Insect biodiversity
About half of all eukaryotes are insects (left side of diagram).
Estimates of the total number of insect species vary considerably, suggesting that there are perhaps some 5.5 million insect species in existence, of which about one million have been described and named. These constitute around half of all eukaryote species, including animals, plants, and fungi. The most diverse insect orders are the Hemiptera (true bugs), Lepidoptera (butterflies and moths), Diptera (true flies), Hymenoptera (wasps, ants, and bees), and Coleoptera (beetles), each with more than 100,000 described species.
Insects are extremely diverse. Five groups each have over 100,000 described species.
True bugs(Hemiptera)
Butterflies and moths(Lepidoptera)
Flies(Diptera)
Wasps(Hymenoptera)
Beetles(Coleoptera)
Distribution and habitats
Insects occur in habitats as varied as snow, freshwater, the tropics, desert, and even the sea.
The snow scorpionfly Boreus hyemalis on snow
The great diving beetle Dytiscus marginalis larva in a pond
The green orchid bee Euglossa dilemma of Central America
The desert locust Schistocerca gregaria laying eggs in sand
Sea skater Halobates on a Hawaii beach
Insects are distributed over every continent and almost every terrestrial habitat. There are many more species in the tropics, especially in rainforests, than in temperate zones. The world's regions have received widely differing amounts of attention from entomologists. The British Isles have been thoroughly surveyed, so that Gullan and Cranston 2014 state that the total of around 22,500 species is probably within 5% of the actual number there; they comment that Canada's list of 30,000 described species is surely over half of the actual total. They add that the 3000 species of the American Arctic must be broadly accurate. In contrast, a large majority of the insect species of the tropics and the southern hemisphere are probably undescribed. Some 30–40,000 species inhabit freshwater; very few insects, perhaps a hundred species, are marine. Insects such as snow scorpionflies flourish in cold habitats including the Arctic and at high altitude. Insects such as desert locusts, ants, beetles, and termites are adapted to some of the hottest and driest environments on earth, such as the Sonoran Desert.
Phylogeny and evolution
External phylogeny
Insects form a clade, a natural group with a common ancestor, among the arthropods. A phylogenetic analysis by Kjer et al. (2016) places the insects among the Hexapoda, six-legged animals with segmented bodies; their closest relatives are the Diplura (bristletails).
Hexapoda
Collembola (springtails)
Protura (coneheads)
Diplura (two-pronged bristletails)
Insecta (=Ectognatha)
Internal phylogeny
The internal phylogeny is based on the works of Wipfler et al. 2019 for the Polyneoptera, Johnson et al. 2018 for the Paraneoptera, and Kjer et al. 2016 for the Holometabola. The numbers of described extant species (boldface for groups with over 100,000 species) are from Stork 2018.
Insecta
Monocondylia
Archaeognatha (hump-backed/jumping bristletails, 513 spp)
Dicondylia
Zygentoma (silverfish, firebrats, fishmoths, 560 spp)
Pterygota
Palaeoptera
Odonata (dragonflies and damselflies, 5,899 spp)
Ephemeroptera (mayflies, 3,240 spp)
Neoptera
Polyneoptera
Zoraptera (angel insects, 37 spp)
Dermaptera (earwigs, 1,978 spp)
Plecoptera (stoneflies, 3,743 spp)
Orthoptera (grasshoppers, crickets, katydids, 23,855 spp)
Grylloblattodea (ice crawlers, 34 spp)
Mantophasmatodea (gladiators, 15 spp)
Phasmatodea (stick insects, 3,014 spp)
Embioptera (webspinners, 463 spp)
Dictyoptera
Mantodea (mantises, 2,400 spp)
Blattodea (cockroaches and termites, 7,314 spp)
Eumetabola
Paraneoptera
Psocodea (book lice, barklice and sucking lice, 11,000 spp)
Hemiptera (true bugs, 103,590 spp)
Thysanoptera (thrips, 5,864 spp)
Holometabola
Hymenoptera (sawflies, wasps, bees, ants, 116,861 spp)
Neuropteroidea
Coleopterida
Strepsiptera (twisted-wing flies, 609 spp)
Coleoptera (beetles, 386,500 spp)
Neuropterida
Raphidioptera (snakeflies, 254 spp)
Neuroptera (lacewings, 5,868 spp)
Megaloptera (alderflies and dobsonflies, 354 spp)
Panorpida
Amphiesmenoptera
Lepidoptera (butterflies and moths, 157,338 spp)
Trichoptera (caddisflies, 14,391 spp)
Antliophora
Diptera (true flies, 155,477 spp)
Mecoptera (scorpionflies, 757 spp)
Siphonaptera (fleas, 2,075 spp)
larvae, pupae
wings flex over abdomen
wings
Taxonomy
Early
Further information: Aristotle's biology § Classification, and Insecta in the 10th edition of Systema Naturae
Diagram of Linnaeus's key to his seven orders of insect, 1758
Aptera
wingless
Diptera
2‑winged
Coleoptera
forewings fully hardened
Hemiptera
forewings partly hardened
dissimilar pairs
Lepidoptera
wings scaly
Neuroptera
no sting
Hymenoptera
sting
wings membranous
similar pairs
4‑winged
winged
Insecta
Aristotle was the first to describe the insects as a distinct group. He placed them as the second-lowest level of animals on his scala naturae, above the spontaneously generating sponges and worms, but below the hard-shelled marine snails. His classification remained in use for many centuries.
In 1758, in his Systema Naturae, Carl Linnaeus divided the animal kingdom into six classes including Insecta. He created seven orders of insect according to the structure of their wings. These were the wingless Aptera, the 2-winged Diptera, and five 4-winged orders: the Coleoptera with fully-hardened forewings; the Hemiptera with partly-hardened forewings; the Lepidoptera with scaly wings; the Neuroptera with membranous wings but no sting; and the Hymenoptera, with membranous wings and a sting.
Jean-Baptiste de Lamarck, in his 1809 Philosophie Zoologique, treated the insects as one of nine invertebrate phyla. In his 1817 Le Règne Animal, Georges Cuvier grouped all animals into four embranchements ("branches" with different body plans), one of which was the articulated animals, containing arthropods and annelids. This arrangement was followed by the embryologist Karl Ernst von Baer in 1828, the zoologist Louis Agassiz in 1857, and the comparative anatomist Richard Owen in 1860. In 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, one of which was Metazoa for the multicellular animals. It had five phyla, including the articulates.
Modern
See also: Category:Insect orders and Category:Insect families
Traditional morphology-based systematics have usually given the Hexapoda the rank of superclass, and identified four groups within it: insects (Ectognatha), Collembola, Protura, and Diplura, the latter three being grouped together as the Entognatha on the basis of internalized mouth parts.
The use of phylogenetic data has brought about numerous changes in relationships above the level of orders. Insects can be divided into two groups historically treated as subclasses: wingless insects or Apterygota, and winged insects or Pterygota. The Apterygota traditionally consisted of the primitively wingless orders Archaeognatha (jumping bristletails) and Zygentoma (silverfish). However, Apterygota is not monophyletic, as Archaeognatha are sister to all other insects, based on the arrangement of their mandibles, while the Pterygota, the winged insects, emerged from within the Dicondylia, alongside the Zygentoma.
The Pterygota (Palaeoptera and Neoptera) are winged and have hardened plates on the outside of their body segments; the Neoptera have muscles that allow their wings to fold flat over the abdomen. Neoptera can be divided into groups with incomplete metamorphosis (Polyneoptera and Paraneoptera) and those with complete metamorphosis (Holometabola). The molecular finding that the traditional louse orders Mallophaga and Anoplura are within Psocoptera has led to the new taxon Psocodea. Phasmatodea and Embiidina have been suggested to form the Eukinolabia. Mantodea, Blattodea, and Isoptera form a monophyletic group, Dictyoptera. Fleas are now thought to be closely related to boreid mecopterans.
Evolutionary history
Main article: Evolution of insects
The oldest fossil that may be a primitive wingless insect is Leverhulmia from the Early Devonian Windyfield chert. The oldest known flying insects are from the mid-Carboniferous, around 328–324 million years ago. The group subsequently underwent a rapid explosive diversification. Claims that they originated substantially earlier, during the Silurian or Devonian (some 400 million years ago) based on molecular clock estimates, are unlikely to be correct, given the fossil record.
Four large-scale radiations of insects have occurred: beetles (from about 300 million years ago), flies (from about 250 million years ago), moths and wasps (both from about 150 million years ago).
The remarkably successful Hymenoptera (wasps, bees, and ants) appeared some 200 million years ago in the Triassic period, but achieved their wide diversity more recently in the Cenozoic era, which began 66 million years ago. Some highly successful insect groups evolved in conjunction with flowering plants, a powerful illustration of coevolution. Insects were among the earliest terrestrial herbivores and acted as major selection agents on plants. Plants evolved chemical defenses against this herbivory and the insects, in turn, evolved mechanisms to deal with plant toxins. Many insects make use of these toxins to protect themselves from their predators. Such insects often advertise their toxicity using warning colors.
The giant dragonfly-like insect Meganeura monyi grew to wingspans of 75 cm (2 ft 6 in) in the late Carboniferous, around 300 million years ago.
Beetle Moravocoleus permianus, fossil and reconstruction, from the Early Permian
Hymenoptera such as this Iberomaimetsha from the Early Cretaceous, around 100 million years ago.
Morphology and physiology
Main article: Insect morphology
External
Insect morphology A- Head B- Thorax C- Abdomen antennaocellus (lower)ocellus (upper)compound eyebrain (cerebral ganglia)prothoraxdorsal blood vesseltracheal tubes (trunk with spiracle)mesothoraxmetathoraxforewinghindwingmidgut (stomach)dorsal tube (heart)ovaryhindgut (intestine, rectum, anus)anusoviductnerve cord (abdominal ganglia)Malpighian tubulestarsal padsclawstarsustibiafemurtrochanterforegut (crop, gizzard)thoracic ganglioncoxasalivary glandsubesophageal ganglionmouthparts
Three-part body
Insects have a segmented body supported by an exoskeleton, the hard outer covering made mostly of chitin. The body is organized into three interconnected units: the head, thorax and abdomen. The head supports a pair of sensory antennae, a pair of compound eyes, zero to three simple eyes (or ocelli) and three sets of variously modified appendages that form the mouthparts. The thorax carries the three pairs of legs and up to two pairs of wings. The abdomen contains most of the digestive, respiratory, excretory and reproductive structures.
Segmentation
Further information: Insect morphology
The head is enclosed in a hard, heavily sclerotized, unsegmented head capsule, which contains most of the sensing organs, including the antennae, compound eyes, ocelli, and mouthparts. The thorax is composed of three sections named (from front to back) the prothorax, mesothorax and metathorax. The prothorax carries the first pair of legs. The mesothorax carries the second pair of legs and the front wings. The metathorax carries the third pair of legs and the hind wings. The abdomen is the largest part of the insect, typically with 11–12 segments, and is less strongly sclerotized than the head or thorax. Each segment of the abdomen has sclerotized upper and lower plates (the tergum and sternum), connected to adjacent sclerotized parts by membranes. Each segment carries a pair of spiracles.
Exoskeleton
Main article: Arthropod cuticle
The outer skeleton, the cuticle, is made up of two layers: the epicuticle, a thin and waxy water-resistant outer layer without chitin, and a lower layer, the thick chitinous procuticle. The procuticle has two layers: an outer exocuticle and an inner endocuticle. The tough and flexible endocuticle is built from numerous layers of fibrous chitin and proteins, criss-crossing each other in a sandwich pattern, while the exocuticle is rigid and sclerotized. As an adaptation to life on land, insects have an enzyme that uses atmospheric oxygen to harden their cuticle, unlike crustaceans which use heavy calcium compounds for the same purpose. This makes the insect exoskeleton a lightweight material.
Internal systems
Main article: Insect physiology
Nervous
The nervous system of an insect consists of a brain and a ventral nerve cord. The head capsule is made up of six fused segments, each with either a pair of ganglia, or a cluster of nerve cells outside of the brain. The first three pairs of ganglia are fused into the brain, while the three following pairs are fused into a structure of three pairs of ganglia under the insect's esophagus, called the subesophageal ganglion. The thoracic segments have one ganglion on each side, connected into a pair per segment. This arrangement is also seen in the first eight segments of the abdomen. Many insects have fewer ganglia than this. Insects are capable of learning.
Digestive
An insect uses its digestive system to extract nutrients and other substances from the food it consumes. There is extensive variation among different orders, life stages, and even castes in the digestive system of insects. The gut runs lengthwise through the body. It has three sections, with paired salivary glands and salivary reservoirs. By moving its mouthparts the insect mixes its food with saliva. Some insects, like flies, expel digestive enzymes onto their food to break it down, but most insects digest their food in the gut. The foregut is lined with cuticule as protection from tough food. It includes the mouth, pharynx, and crop which stores food. Digestion starts in the mouth with enzymes in the saliva. Strong muscles in the pharynx pump fluid into the mouth, lubricating the food, and enabling certain insects to feed on blood or from the xylem and phloem transport vessels of plants. Once food leaves the crop, it passes to the midgut, where the majority of digestion takes place. Microscopic projections, microvilli, increase the surface area of the wall to absorb nutrients. In the hindgut, undigested food particles are joined by uric acid to form fecal pellets; most of the water is absorbed, leaving a dry pellet to be eliminated. Insects may have one to hundreds of Malpighian tubules. These remove nitrogenous wastes from the hemolymph of the insect and regulate osmotic balance. Wastes and solutes are emptied directly into the alimentary canal, at the junction between the midgut and hindgut.
Reproductive
Main article: Insect reproductive system
The reproductive system of female insects consist of a pair of ovaries, accessory glands, one or more spermathecae to store sperm, and ducts connecting these parts. The ovaries are made up of a variable number of egg tubes, ovarioles. Female insects make eggs, receive and store sperm, manipulate sperm from different males, and lay eggs. Accessory glands produce substances to maintain sperm and to protect the eggs. They can produce glue and protective substances for coating eggs, or tough coverings for a batch of eggs called oothecae.
For males, the reproductive system consists of one or two testes, suspended in the body cavity by tracheae. The testes contain sperm tubes or follicles in a membranous sac. These connect to a duct that leads to the outside. The terminal portion of the duct may be sclerotized to form the intromittent organ, the aedeagus.
Respiratory
Main article: Respiratory system of insects
The tube-like heart (green) of the mosquito Anopheles gambiae extends horizontally across the body, interlinked with the diamond-shaped wing muscles (also green) and surrounded by pericardial cells (red). Blue depicts cell nuclei.
Insect respiration is accomplished without lungs. Instead, insects have a system of internal tubes and sacs through which gases either diffuse or are actively pumped, delivering oxygen directly to tissues that need it via their tracheae and tracheoles. In most insects, air is taken in through paired spiracles, openings on the sides of the abdomen and thorax. The respiratory system limits the size of insects. As insects get larger, gas exchange via spiracles becomes less efficient, and thus the heaviest insect currently weighs less than 100 g. However, with increased atmospheric oxygen levels, as were present in the late Paleozoic, larger insects were possible, such as dragonflies with wingspans of more than two feet (60 cm). Gas exchange patterns in insects range from continuous and diffusive ventilation, to discontinuous.
Circulatory
Further information: Insect physiology § Circulatory system
Because oxygen is delivered directly to tissues via tracheoles, the circulatory system is not used to carry oxygen, and is therefore greatly reduced. The insect circulatory system is open; it has no veins or arteries, and instead consists of little more than a single, perforated dorsal tube that pulses peristaltically. This dorsal blood vessel is divided into two sections: the heart and aorta. The dorsal blood vessel circulates the hemolymph, arthropods' fluid analog of blood, from the rear of the body cavity forward. Hemolymph is composed of plasma in which hemocytes are suspended. Nutrients, hormones, wastes, and other substances are transported throughout the insect body in the hemolymph. Hemocytes include many types of cells that are important for immune responses, wound healing, and other functions. Hemolymph pressure may be increased by muscle contractions or by swallowing air into the digestive system to aid in molting.
Sensory
Further information: Insect physiology § Sensory organs
Most insects have a pair of large compound eyes and other sensory organs such as antennae able to detect movements and chemical stimuli on their heads.
Many insects possess numerous specialized sensory organs able to detect stimuli including limb position (proprioception) by campaniform sensilla, light, water, chemicals (senses of taste and smell), sound, and heat. Some insects such as bees can perceive ultraviolet wavelengths, or detect polarized light, while the antennae of male moths can detect the pheromones of female moths over distances of over a kilometer. There is a trade-off between visual acuity and chemical or tactile acuity, such that most insects with well-developed eyes have reduced or simple antennae, and vice versa. Insects perceive sound by different mechanisms, such as thin vibrating membranes (tympana). Insects were the earliest organisms to produce and sense sounds. Hearing has evolved independently at least 19 times in different insect groups.
Most insects, except some cave crickets, are able to perceive light and dark. Many have acute vision capable of detecting small and rapid movements. The eyes may include simple eyes or ocelli as well as larger compound eyes. Many species can detect light in the infrared, ultraviolet and visible light wavelengths, with color vision. Phylogenetic analysis suggests that UV-green-blue trichromacy existed from at least the Devonian period, some 400 million years ago.
The individual lenses in compound eyes are immobile, but fruit flies have photoreceptor cells underneath each lens which move rapidly in and out of focus, in a series of movements called photoreceptor microsaccades. This gives them, and possibly many other insects, a much clearer image of the world than previously assumed.
An insect's sense of smell is via chemical receptors, usually on the antennae and the mouthparts. These detect both airborne volatile compounds and odorants on surfaces, including pheromones from other insects and compounds released by food plants. Insects use olfaction to locate mating partners, food, and places to lay eggs, and to avoid predators. It is thus an extremely important sense, enabling insects to discriminate between thousands of volatile compounds.
Some insects are capable of magnetoreception; ants and bees navigate using it both locally (near their nests) and when migrating. The Brazilian stingless bee detects magnetic fields using the hair-like sensilla on its antennae.
Reproduction and development
Life-cycles
Butterflies mating
The majority of insects hatch from eggs. The fertilization and development takes place inside the egg, enclosed by a shell (chorion) that consists of maternal tissue. In contrast to eggs of other arthropods, most insect eggs are drought resistant. This is because inside the chorion two additional membranes develop from embryonic tissue, the amnion and the serosa. This serosa secretes a cuticle rich in chitin that protects the embryo against desiccation. Some species of insects, like aphids and tsetse flies, are ovoviviparous: their eggs develop entirely inside the female, and then hatch immediately upon being laid. Some other species, such as in the cockroach genus Diploptera, are viviparous, gestating inside the mother and born alive. Some insects, like parasitoid wasps, are polyembryonic, meaning that a single fertilized egg divides into many separate embryos. Insects may be univoltine, bivoltine or multivoltine, having one, two or many broods in a year.
Aphid giving birth to live female young by parthenogenesis from unfertilized eggs
Other developmental and reproductive variations include haplodiploidy, polymorphism, paedomorphosis or peramorphosis, sexual dimorphism, parthenogenesis, and more rarely hermaphroditism. In haplodiploidy, which is a type of sex-determination system, the offspring's sex is determined by the number of sets of chromosomes an individual receives. This system is typical in bees and wasps.
Some insects are parthenogenetic, meaning that the female can reproduce and give birth without having the eggs fertilized by a male. Many aphids undergo a cyclical form of parthenogenesis in which they alternate between one or many generations of asexual and sexual reproduction. In summer, aphids are generally female and parthenogenetic; in the autumn, males may be produced for sexual reproduction. Other insects produced by parthenogenesis are bees, wasps and ants; in their haplodiploid system, diploid females spawn many females and a few haploid males.
Metamorphosis
Metamorphosis in insects is the process of development that converts young to adults. There are two forms of metamorphosis: incomplete and complete.
Incomplete
Main article: Hemimetabolism
Incomplete metamorphosis in a locust with multiple instars. Egg is not shown. The largest specimen is adult.
Hemimetabolous insects, those with incomplete metamorphosis, change gradually after hatching from the egg by undergoing a series of molts through stages called instars, until the final, adult, stage is reached. An insect molts when it outgrows its exoskeleton, which does not stretch and would otherwise restrict the insect's growth. The molting process begins as the insect's epidermis secretes a new epicuticle inside the old one. After this new epicuticle is secreted, the epidermis releases a mixture of enzymes that digests the endocuticle and thus detaches the old cuticle. When this stage is complete, the insect makes its body swell by taking in a large quantity of water or air, which makes the old cuticle split along predefined weaknesses where the old exocuticle was thinnest.
Complete
Main article: Holometabolism
Life-cycle of butterfly, undergoing complete metamorphosis from egg through caterpillar larvae to pupa and adult
Holometabolism, or complete metamorphosis, is where the insect changes in four stages, an egg or embryo, a larva, a pupa and the adult or imago. In these species, an egg hatches to produce a larva, which is generally worm-like in form. This can be eruciform (caterpillar-like), scarabaeiform (grub-like), campodeiform (elongated, flattened and active), elateriform (wireworm-like) or vermiform (maggot-like). The larva grows and eventually becomes a pupa, a stage marked by reduced movement. There are three types of pupae: obtect, exarate or coarctate. Obtect pupae are compact, with the legs and other appendages enclosed. Exarate pupae have their legs and other appendages free and extended. Coarctate pupae develop inside the larval skin. Insects undergo considerable change in form during the pupal stage, and emerge as adults. Butterflies are well-known for undergoing complete metamorphosis; most insects use this life cycle. Some insects have evolved this system to hypermetamorphosis. Complete metamorphosis is a trait of the most diverse insect group, the Endopterygota.
Communication
Insects that produce sound can generally hear it. Most insects can hear only a narrow range of frequencies related to the frequency of the sounds they can produce. Mosquitoes can hear up to 2 kilohertz. Certain predatory and parasitic insects can detect the characteristic sounds made by their prey or hosts, respectively. Likewise, some nocturnal moths can perceive the ultrasonic emissions of bats, which helps them avoid predation.
Light production
A few insects, such as Mycetophilidae (Diptera) and the beetle families Lampyridae, Phengodidae, Elateridae and Staphylinidae are bioluminescent. The most familiar group are the fireflies, beetles of the family Lampyridae. Some species are able to control this light generation to produce flashes. The function varies with some species using them to attract mates, while others use them to lure prey. Cave dwelling larvae of Arachnocampa (Mycetophilidae, fungus gnats) glow to lure small flying insects into sticky strands of silk. Some fireflies of the genus Photuris mimic the flashing of female Photinus species to attract males of that species, which are then captured and devoured. The colors of emitted light vary from dull blue (Orfelia fultoni, Mycetophilidae) to the familiar greens and the rare reds (Phrixothrix tiemanni, Phengodidae).
Sound production
Insects make sounds mostly by mechanical action of appendages. In grasshoppers and crickets, this is achieved by stridulation. Cicadas make the loudest sounds among the insects by producing and amplifying sounds with special modifications to their body to form tymbals and associated musculature. The African cicada Brevisana brevis has been measured at 106.7 decibels at a distance of 50 cm (20 in). Some insects, such as the Helicoverpa zea moths, hawk moths and Hedylid butterflies, can hear ultrasound and take evasive action when they sense that they have been detected by bats. Some moths produce ultrasonic clicks that warn predatory bats of their unpalatability (acoustic aposematism), while some palatable moths have evolved to mimic these calls (acoustic Batesian mimicry). The claim that some moths can jam bat sonar has been revisited. Ultrasonic recording and high-speed infrared videography of bat-moth interactions suggest the palatable tiger moth really does defend against attacking big brown bats using ultrasonic clicks that jam bat sonar.
Grasshopper stridulation
Several unidentified grasshoppers stridulating
Problems playing this file? See media help.
Very low sounds are produced in various species of Coleoptera, Hymenoptera, Lepidoptera, Mantodea and Neuroptera. These low sounds are produced by the insect's movement, amplified by stridulatory structures on the insect's muscles and joints; these sounds can be used to warn or communicate with other insects. Most sound-making insects also have tympanal organs that can perceive airborne sounds. Some hemipterans, such as the water boatmen, communicate via underwater sounds.
Cricket in garage with familiar call
Communication using surface-borne vibrational signals is more widespread among insects because of size constraints in producing air-borne sounds. Insects cannot effectively produce low-frequency sounds, and high-frequency sounds tend to disperse more in a dense environment (such as foliage), so insects living in such environments communicate primarily using substrate-borne vibrations.
Some species use vibrations for communicating, such as to attract mates as in the songs of the shield bug Nezara viridula. Vibrations can also be used to communicate between species; lycaenid caterpillars, which form a mutualistic association with ants communicate with ants in this way. The Madagascar hissing cockroach has the ability to press air through its spiracles to make a hissing noise as a sign of aggression; the death's-head hawkmoth makes a squeaking noise by forcing air out of their pharynx when agitated, which may also reduce aggressive worker honey bee behavior when the two are close.
Chemical communication
Main articles: Chemical communication in insects and Insect olfaction
Social insects such as ants have multiple types of pheromonal glands, producing different semiochemicals for communication with other insects.
Many insects have evolved chemical means for communication. These semiochemicals are often derived from plant metabolites including those meant to attract, repel and provide other kinds of information. Pheromones are used for attracting mates of the opposite sex, for aggregating conspecific individuals of both sexes, for deterring other individuals from approaching, to mark a trail, and to trigger aggression in nearby individuals. Allomones benefit their producer by the effect they have upon the receiver. Kairomones benefit their receiver instead of their producer. Synomones benefit the producer and the receiver. While some chemicals are targeted at individuals of the same species, others are used for communication across species. The use of scents is especially well-developed in social insects. Cuticular hydrocarbons are nonstructural materials produced and secreted to the cuticle surface to fight desiccation and pathogens. They are important, too, as pheromones, especially in social insects.
Social behavior
Main article: Eusociality
A cathedral mound created by eusocial mound-building termites.Honey bee's figure-eight waggle dance. An orientation 45° to the right of ‘up' on the comb indicates food 45° to the right of the sun. The dancer's rapid waggling blurs her abdomen.
Social insects, such as termites, ants and many bees and wasps, are eusocial. They live together in such large well-organized colonies of genetically similar individuals that they are sometimes considered superorganisms. In particular, reproduction is largely limited to a queen caste; other females are workers, prevented from reproducing by worker policing. Honey bees have evolved a system of abstract symbolic communication where a behavior is used to represent and convey specific information about the environment. In this communication system, called dance language, the angle at which a bee dances represents a direction relative to the sun, and the length of the dance represents the distance to be flown. Bumblebees too have some social communication behaviors. Bombus terrestris, for example, more rapidly learns about visiting unfamiliar, yet rewarding flowers, when they can see a conspecific foraging on the same species.
Only insects that live in nests or colonies possess fine-scale spatial orientation. Some can navigate unerringly to a single hole a few millimeters in diameter among thousands of similar holes, after a trip of several kilometers. In philopatry, insects that hibernate are able to recall a specific location up to a year after last viewing the area of interest. A few insects seasonally migrate large distances between different geographic regions, as in the continent-wide monarch butterfly migration.
Care of young
Eusocial insects build nests, guard eggs, and provide food for offspring full-time. Most insects, however, lead short lives as adults, and rarely interact with one another except to mate or compete for mates. A small number provide parental care, where they at least guard their eggs, and sometimes guard their offspring until adulthood, possibly even feeding them. Many wasps and bees construct a nest or burrow, store provisions in it, and lay an egg upon those provisions, providing no further care.
Locomotion
Flight
Main article: Insect flight
Insects such as hoverflies are capable of rapid and agile flight.
Insects are the only group of invertebrates to have developed flight. The ancient groups of insects in the Palaeoptera, the dragonflies, damselflies and mayflies, operate their wings directly by paired muscles attached to points on each wing base that raise and lower them. This can only be done at a relatively slow rate. All other insects, the Neoptera, have indirect flight, in which the flight muscles cause rapid oscillation of the thorax: there can be more wingbeats than nerve impulses commanding the muscles. One pair of flight muscles is aligned vertically, contracting to pull the top of the thorax down, and the wings up. The other pair runs longitudinally, contracting to force the top of the thorax up and the wings down. Most insects gain aerodynamic lift by creating a spiralling vortex at the leading edge of the wings. Small insects like thrips with tiny feathery wings gain lift using the clap and fling mechanism; the wings are clapped together and pulled apart, flinging vortices into the air at the leading edges and at the wingtips.
The evolution of insect wings has been a subject of debate; it has been suggested they came from modified gills, flaps on the spiracles, or an appendage, the epicoxa, at the base of the legs. More recently, entomologists have favored evolution of wings from lobes of the notum, of the pleuron, or more likely both.
In the Carboniferous age, the dragonfly-like Meganeura had as much as a 50 cm (20 in) wide wingspan. The appearance of gigantic insects is consistent with high atmospheric oxygen at that time, as the respiratory system of insects constrains their size. The largest flying insects today are much smaller, with the largest wingspan belonging to the white witch moth (Thysania agrippina), at approximately 28 cm (11 in).
Unlike birds, small insects are swept along by the prevailing winds although many larger insects migrate. Aphids are transported long distances by low-level jet streams.
Walking
Further information: Walking § Insects
Spatial and temporal stepping pattern of walking desert ants performing an alternating tripod gait. Recording rate: 500 fps, Playback rate: 10 fps.
Many adult insects use six legs for walking, with an alternating tripod gait. This allows for rapid walking with a stable stance; it has been studied extensively in cockroaches and ants. For the first step, the middle right leg and the front and rear left legs are in contact with the ground and move the insect forward, while the front and rear right leg and the middle left leg are lifted and moved forward to a new position. When they touch the ground to form a new stable triangle, the other legs can be lifted and brought forward in turn. The purest form of the tripedal gait is seen in insects moving at high speeds. However, this type of locomotion is not rigid and insects can adapt a variety of gaits. For example, when moving slowly, turning, avoiding obstacles, climbing or slippery surfaces, four (tetrapodal) or more feet (wave-gait) may be touching the ground. Cockroaches are among the fastest insect runners and, at full speed, adopt a bipedal run. More sedate locomotion is seen in the well-camouflaged stick insects (Phasmatodea). A small number of species such as Water striders can move on the surface of water; their claws are recessed in a special groove, preventing the claws from piercing the water's surface film. The ocean-skaters in the genus Halobates even live on the surface of open oceans, a habitat that has few insect species.
Swimming
Main article: Aquatic insects
The backswimmer Notonecta glauca underwater, showing its paddle-like hindleg adaptation
A large number of insects live either part or the whole of their lives underwater. In many of the more primitive orders of insect, the immature stages are aquatic. In some groups, such as water beetles, the adults too are aquatic.
Many of these species are adapted for under-water locomotion. Water beetles and water bugs have legs adapted into paddle-like structures. Dragonfly naiads use jet propulsion, forcibly expelling water out of their rectal chamber. Other insects such as the rove beetle Stenus emit pygidial gland surfactant secretions that reduce surface tension; this enables them to move on the surface of water by Marangoni propulsion.
Ecology
Main article: Insect ecology
Insects play many critical roles in ecosystems, including soil turning and aeration, dung burial, pest control, pollination and wildlife nutrition. For instance, termites modify the environment around their nests, encouraging grass growth; many beetles are scavengers; dung beetles recycle biological materials into forms useful to other organisms. Insects are responsible for much of the process by which topsoil is created.
Defense
Main article: Defense in insects
Reduvius personatus, the masked hunter bug nymph, camouflages itself with sand grains to avoid predators.
Insects are mostly small, soft bodied, and fragile compared to larger lifeforms. The immature stages are small, move slowly or are immobile, and so all stages are exposed to predation and parasitism. Insects accordingly employ multiple defensive strategies, including camouflage, mimicry, toxicity and active defense.
Many insects rely on camouflage to avoid being noticed by their predators or prey. It is common among leaf beetles and weevils that feed on wood or vegetation. Stick insects mimic the forms of sticks and leaves.
Many insects use mimicry to deceive predators into avoiding them. In Batesian mimicry, edible species, such as of hoverflies (the mimics), gain a survival advantage by resembling inedible species (the models). In Müllerian mimicry, inedible species, such as of wasps and bees, resemble each other so as to reduce the sampling rate by predators who need to learn that those insects are inedible. Heliconius butterflies, many of which are toxic, form Müllerian complexes, advertising their inedibility.
Chemical defense is common among Coleoptera and Lepidoptera, usually being advertised by bright warning colors (aposematism), as in the monarch butterfly. As larvae, they obtain their toxicity by sequestering chemicals from the plants they eat into their own tissues. Some manufacture their own toxins. Predators that eat poisonous butterflies and moths may vomit violently, learning not to eat insects with similar markings; this is the basis of Müllerian mimicry.
Some ground beetles of the family Carabidae actively defend themselves, spraying chemicals from their abdomen with great accuracy, to repel predators.
Pollination
Main article: Entomophily
European honey bee carrying pollen in a pollen basket back to the hive
Pollination is the process by which pollen is transferred in the reproduction of plants, thereby enabling fertilisation and sexual reproduction. Most flowering plants require an animal to do the transportation. The majority of pollination is by insects. Because insects usually receive benefit for the pollination in the form of energy rich nectar it is a mutualism. The various flower traits, such as bright colors and pheromones that coevolved with their pollinators, have been called pollination syndromes, though around one third of flowers cannot be assigned to a single syndrome.
Parasitism
Further information: Parasitism and Parasitoid wasp
Many insects are parasitic. The largest group, with over 100,000 species and perhaps over a million, consists of a single clade of parasitoid wasps among the Hymenoptera. These are parasites of other insects, eventually killing their hosts. Some are hyper-parasites, as their hosts are other parasitoid wasps. Several groups of insects can be considered as either micropredators or external parasites; for example, many hemipteran bugs have piercing and sucking mouthparts, adapted for feeding on plant sap, while species in groups such as fleas, lice, and mosquitoes are hematophagous, feeding on the blood of animals.
A parasitoid wasp ovipositing into an aphid
Plant parasite or micropredator: a coreid bug sucking plant sap
Human head-lice are directly transmitted obligate ectoparasites.
Relationship to humans
Main article: Human interactions with insects
As pests
Aedes aegypti, the yellow fever mosquito, is a vector of several diseases.
Main article: Pest insect
Many insects are considered pests by humans. These include parasites of people and livestock, such as lice and bed bugs; mosquitoes act as vectors of several diseases. Other pests include insects like termites that damage wooden structures; herbivorous insects such as locusts, aphids, and thrips that destroy agricultural crops, or like wheat weevils damage stored agricultural produce. Farmers have often attempted to control insects with chemical insecticides, but increasingly rely on biological pest control. This uses one organism to reduce the population density of a pest organism; it is a key element of integrated pest management. Biological control is favored because insecticides can cause harm to ecosystems far beyond the intended pest targets.
In beneficial roles
See also: Economic entomology § Beneficial insects
Silkworms were domesticated for silk for over 5000 years. Here, silk cocoons are being unrolled.
Pollination of flowering plants by insects including bees, butterflies, flies, and beetles, is economically important. The value of insect pollination of crops and fruit trees was estimated in 2021 to be about $34 billion in the US alone.
Insects produce useful substances such as honey, wax, lacquer and silk. Honey bees have been cultured by humans for thousands of years for honey. Beekeeping in pottery vessels began about 9,000 years ago in North Africa. The silkworm has greatly affected human history, as silk-driven trade established relationships between China and the rest of the world.
Insects that feed on or parasitise other insects are beneficial to humans if they thereby reduce damage to agriculture and human structures. For example, aphids feed on crops, causing economic loss, but ladybugs feed on aphids, and can be used to control them. Insects account for the vast majority of insect consumption.
Fly larvae (maggots) were formerly used to treat wounds to prevent or stop gangrene, as they would only consume dead flesh. This treatment is finding modern usage in some hospitals. Insects have gained attention as potential sources of drugs and other medicinal substances. Adult insects, such as crickets and insect larvae of various kinds, are commonly used as fishing bait.
Population declines
Main article: Decline in insect populations
At least 66 insect species extinctions have been recorded since 1500, many of them on oceanic islands. Declines in insect abundance have been attributed to human activity in the form of artificial lighting, land use changes such as urbanization or farming, pesticide use, and invasive species. A 2019 research review suggested that a large proportion of insect species is threatened with extinction in the 21st century, though the details have been disputed. A larger 2020 meta-study, analyzing data from 166 long-term surveys, suggested that populations of terrestrial insects are indeed decreasing rapidly, by about 9% per decade.
In research
The fruit fly Drosophila melanogaster is a widely used model organism.
Insects play important roles in biological research. For example, because of its small size, short generation time and high fecundity, the common fruit fly Drosophila melanogaster is a model organism for studies in the genetics of eukaryotes, including genetic linkage, interactions between genes, chromosomal genetics, development, behavior and evolution. Because genetic systems are well conserved among eukaryotes, understanding basic cellular processes like DNA replication or transcription in fruit flies can help to understand those processes in other eukaryotes, including humans. The genome of D. melanogaster was sequenced in 2000, reflecting the organism's important role in biological research. It was found that 70% of the fly genome is similar to the human genome, supporting the theory of evolution.
As food
Main article: Insects as food
Witchetty grubs are prized as high-protein foods by Aboriginal Australians.
Insects are consumed as food in 80% of the world's nations, by people in roughly 3000 ethnic groups. In Africa, locally abundant species of locusts and termites are a common traditional human food source. Some, especially deep-fried cicadas, are considered to be delicacies. Insects have a high protein content for their mass, and some authors suggest their potential as a major source of protein in human nutrition. In most first-world countries, however, entomophagy (the eating of insects), is taboo. They are also recommended by armed forces as a survival food for troops in adversity. Because of the abundance of insects and a worldwide concern of food shortages, the Food and Agriculture Organization of the United Nations considers that people throughout the world may have to eat insects as a food staple. Insects are noted for their nutrients, having a high content of protein, minerals and fats and are already regularly eaten by one-third of the world's population.
In other products
Black soldier fly larvae can provide protein and fats for use in cosmetics. Insect cooking oil, insect butter and fatty alcohols can be made from such insects as the superworm (Zophobas morio). Insect species including the black soldier fly or the housefly in their maggot forms, and beetle larvae such as mealworms, can be processed and used as feed for farmed animals including chicken, fish and pigs. Many species of insects are sold and kept as pets.
In religion and folklore
Further information: Insects in mythology
Ancient Egyptian scarab with separate wings, c. 712-342 BC
Scarab beetles held religious and cultural symbolism in ancient Egypt, Greece and some shamanistic Old World cultures. The ancient Chinese regarded cicadas as symbols of rebirth or immortality. In Mesopotamian literature, the epic poem of Gilgamesh has allusions to Odonata that signify the impossibility of immortality. Among the Aborigines of Australia of the Arrernte language groups, honey ants and witchetty grubs served as personal clan totems. In the case of the 'San' bush-men of the Kalahari, it is the praying mantis that holds much cultural significance including creation and zen-like patience in waiting.
See also
Entomology
Ethnoentomology
Flying and gliding animals
Insect-borne diseases
Notes
^ The Museum of New Zealand notes that "in everyday conversation", bug "refers to land arthropods with at least six legs, such as insects, spiders, and centipedes". In a chapter on "Bugs That Are Not Insects", entomologist Gilbert Walbauer specifies centipedes, millipedes, arachnids (spiders, daddy longlegs, scorpions, mites, chiggers and ticks) as well as the few terrestrial crustaceans (sowbugs and pillbugs). | biology | 91321 | https://no.wikipedia.org/wiki/Biologisk%20vektor | Biologisk vektor | Biologisk vektor er betegnelsen på organismer som forårsaker spredning av patogen (biologiske agenter som kan forårsake sykdommer). En biologisk vektor vil ikke nødvendigvis bli infisert av smitten. Ofte vil insekt som flått og mygg være biologisk vektor. Også mennesket kan være en biologisk vektor, eksempelvis ved at det kan bære viruset som fremskaffer munn- og klovsyke (da uten å bli infisert selv). Innen genterapi kan et virus være biologisk vektor, idet det brukes til å avlevere patogen til andre organismer. Også innen genetikk bruker man begrepet biologisk vektor, om DNA-konstruksjoner som brukes i byggingen av andre.
Mikrobiologi | norwegian_bokmål | 0.796582 |
insescts_six_legs/Arthropodleg.txt | Jump to content
Main menu
Main menu
move to sidebar hide
Navigation
* [ Main page ](/wiki/Main_Page "Visit the main page \[z\]")
* [ Contents ](/wiki/Wikipedia:Contents "Guides to browsing Wikipedia")
* [ Current events ](/wiki/Portal:Current_events "Articles related to current events")
* [ Random article ](/wiki/Special:Random "Visit a randomly selected article \[x\]")
* [ About Wikipedia ](/wiki/Wikipedia:About "Learn about Wikipedia and how it works")
* [ Contact us ](//en.wikipedia.org/wiki/Wikipedia:Contact_us "How to contact Wikipedia")
* [ Donate ](https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en "Support us by donating to the Wikimedia Foundation")
Contribute
* [ Help ](/wiki/Help:Contents "Guidance on how to use and edit Wikipedia")
* [ Learn to edit ](/wiki/Help:Introduction "Learn how to edit Wikipedia")
* [ Community portal ](/wiki/Wikipedia:Community_portal "The hub for editors")
* [ Recent changes ](/wiki/Special:RecentChanges "A list of recent changes to Wikipedia \[r\]")
* [ Upload file ](/wiki/Wikipedia:File_upload_wizard "Add images or other media for use on Wikipedia")
[ 
 
](/wiki/Main_Page)
[ Search ](/wiki/Special:Search "Search Wikipedia \[f\]")
Search
* [ Create account ](/w/index.php?title=Special:CreateAccount&returnto=Arthropod+leg "You are encouraged to create an account and log in; however, it is not mandatory")
* [ Log in ](/w/index.php?title=Special:UserLogin&returnto=Arthropod+leg "You're encouraged to log in; however, it's not mandatory. \[o\]")
Personal tools
* [ Create account ](/w/index.php?title=Special:CreateAccount&returnto=Arthropod+leg "You are encouraged to create an account and log in; however, it is not mandatory")
* [ Log in ](/w/index.php?title=Special:UserLogin&returnto=Arthropod+leg "You're encouraged to log in; however, it's not mandatory. \[o\]")
Pages for logged out editors [ learn more ](/wiki/Help:Introduction)
* [ Contributions ](/wiki/Special:MyContributions "A list of edits made from this IP address \[y\]")
* [ Talk ](/wiki/Special:MyTalk "Discussion about edits from this IP address \[n\]")
## Contents
move to sidebar hide
* (Top)
* 1 Biramous and uniramous
* 2 Chelicerata
* 3 Crustacea
* 4 Myriapoda
* 5 Insects Toggle Insects subsection
* 5.1 Fundamental morphology of insect legs
* 5.1.1 Coxa
* 5.1.2 Trochanter
* 5.1.3 Femur
* 5.1.4 Tibia
* 5.1.5 Tarsus
* 5.2 Variations in functional anatomy of insect legs
* 6 Evolution and homology of arthropod legs Toggle Evolution and homology of arthropod legs subsection
* 6.1 Leg modification classifications
* 7 See also
* 8 References
Toggle the table of contents
# Arthropod leg
13 languages
* [ Català ](https://ca.wikipedia.org/wiki/Ap%C3%A8ndix_\(artr%C3%B2podes\) "Apèndix \(artròpodes\) – Catalan")
* [ Español ](https://es.wikipedia.org/wiki/Pata_\(artr%C3%B3podos\) "Pata \(artrópodos\) – Spanish")
* [ فارسی ](https://fa.wikipedia.org/wiki/%D9%BE%D8%A7%DB%8C_%D8%A8%D9%86%D8%AF%D9%BE%D8%A7%DB%8C%D8%A7%D9%86 "پای بندپایان – Persian")
* [ Français ](https://fr.wikipedia.org/wiki/Patte_des_arthropodes "Patte des arthropodes – French")
* [ Galego ](https://gl.wikipedia.org/wiki/Pata_\(artr%C3%B3podos\) "Pata \(artrópodos\) – Galician")
* [ 한국어 ](https://ko.wikipedia.org/wiki/%EA%B0%80%EC%8A%B4%EB%8B%A4%EB%A6%AC "가슴다리 – Korean")
* [ עברית ](https://he.wikipedia.org/wiki/%D7%A8%D7%92%D7%9C_\(%D7%A4%D7%A8%D7%95%D7%A7%D7%99-%D7%A8%D7%92%D7%9C%D7%99%D7%99%D7%9D\) "רגל \(פרוקי-רגליים\) – Hebrew")
* [ Nederlands ](https://nl.wikipedia.org/wiki/Coxa "Coxa – Dutch")
* [ 日本語 ](https://ja.wikipedia.org/wiki/%E9%96%A2%E7%AF%80%E8%82%A2 "関節肢 – Japanese")
* [ Português ](https://pt.wikipedia.org/wiki/Pata_\(artr%C3%B3podes\) "Pata \(artrópodes\) – Portuguese")
* [ Русский ](https://ru.wikipedia.org/wiki/%D0%9D%D0%BE%D0%B3%D0%B8_%D0%BD%D0%B0%D1%81%D0%B5%D0%BA%D0%BE%D0%BC%D1%8B%D1%85 "Ноги насекомых – Russian")
* [ Українська ](https://uk.wikipedia.org/wiki/%D0%9D%D0%BE%D0%B3%D0%B8_%D0%BA%D0%BE%D0%BC%D0%B0%D1%85 "Ноги комах – Ukrainian")
* [ 中文 ](https://zh.wikipedia.org/wiki/%E8%85%BF_\(%E8%8A%82%E8%82%A2%E5%8A%A8%E7%89%A9\) "腿 \(节肢动物\) – Chinese")
[ Edit links
](https://www.wikidata.org/wiki/Special:EntityPage/Q3133438#sitelinks-
wikipedia "Edit interlanguage links")
* [ Article ](/wiki/Arthropod_leg "View the content page \[c\]")
* [ Talk ](/wiki/Talk:Arthropod_leg "Discuss improvements to the content page \[t\]")
English
* [ Read ](/wiki/Arthropod_leg)
* [ Edit ](/w/index.php?title=Arthropod_leg&action=edit "Edit this page \[e\]")
* [ View history ](/w/index.php?title=Arthropod_leg&action=history "Past revisions of this page \[h\]")
Tools
Tools
move to sidebar hide
Actions
* [ Read ](/wiki/Arthropod_leg)
* [ Edit ](/w/index.php?title=Arthropod_leg&action=edit "Edit this page \[e\]")
* [ View history ](/w/index.php?title=Arthropod_leg&action=history)
General
* [ What links here ](/wiki/Special:WhatLinksHere/Arthropod_leg "List of all English Wikipedia pages containing links to this page \[j\]")
* [ Related changes ](/wiki/Special:RecentChangesLinked/Arthropod_leg "Recent changes in pages linked from this page \[k\]")
* [ Upload file ](/wiki/Wikipedia:File_Upload_Wizard "Upload files \[u\]")
* [ Special pages ](/wiki/Special:SpecialPages "A list of all special pages \[q\]")
* [ Permanent link ](/w/index.php?title=Arthropod_leg&oldid=1221090000 "Permanent link to this revision of this page")
* [ Page information ](/w/index.php?title=Arthropod_leg&action=info "More information about this page")
* [ Cite this page ](/w/index.php?title=Special:CiteThisPage&page=Arthropod_leg&id=1221090000&wpFormIdentifier=titleform "Information on how to cite this page")
* [ Get shortened URL ](/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FArthropod_leg)
* [ Download QR code ](/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FArthropod_leg)
* [ Wikidata item ](https://www.wikidata.org/wiki/Special:EntityPage/Q3133438 "Structured data on this page hosted by Wikidata \[g\]")
Print/export
* [ Download as PDF ](/w/index.php?title=Special:DownloadAsPdf&page=Arthropod_leg&action=show-download-screen "Download this page as a PDF file")
* [ Printable version ](/w/index.php?title=Arthropod_leg&printable=yes "Printable version of this page \[p\]")
From Wikipedia, the free encyclopedia
Form of jointed appendage of arthropods
The **arthropod leg** is a form of jointed [ appendage ](/wiki/Appendage
"Appendage") of [ arthropods ](/wiki/Arthropod "Arthropod") , usually used for
[ walking ](/wiki/Walking "Walking") . Many of the terms used for arthropod
leg segments (called **podomeres** ) are of [ Latin ](/wiki/Latin "Latin")
origin, and may be confused with terms for bones: _coxa_ (meaning [ hip
](/wiki/Hip_\(anatomy\) "Hip \(anatomy\)") , pl. : _coxae_ ), _trochanter_ ,
_femur_ ( pl. : _femora_ ), _tibia_ ( pl. : _tibiae_ ), _tarsus_ ( pl. :
_tarsi_ ), _ischium_ ( pl. : _ischia_ ), _metatarsus_ , _carpus_ ,
_dactylus_ (meaning [ finger ](/wiki/Finger "Finger") ), _patella_ ( pl. :
_patellae_ ).
[ Homologies ](/wiki/Homology_\(biology\) "Homology \(biology\)") of leg
segments between groups are difficult to prove and are the source of much
argument. Some authors posit up to eleven segments per leg for the [ most
recent common ancestor ](/wiki/Most_recent_common_ancestor "Most recent common
ancestor") of [ extant ](/wiki/Neontology "Neontology") arthropods [1] but
modern arthropods have eight or fewer. It has been argued [2] [3] that the
ancestral leg need not have been so complex, and that other events, such as
successive loss of function of a [ _Hox_ -gene ](/wiki/Homeobox "Homeobox") ,
could result in [ parallel ](/wiki/Parallel_evolution "Parallel evolution")
gains of leg segments.
In arthropods, each of the leg segments articulates with the next segment in a
[ hinge joint ](/wiki/Hinge_joint "Hinge joint") and may only bend in one
plane. This means that a greater number of segments is required to achieve the
same kinds of movements that are possible in vertebrate animals, which have
rotational [ ball-and-socket joints ](/wiki/Ball-and-socket_joint "Ball-and-
socket joint") at the base of the fore and hind limbs. [4]
## Biramous and uniramous [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=1 "Edit section:
Biramous and uniramous") ]
[
](/wiki/File:20200213_arthropod_uniramous_arthropodized_appendage_morphology_en.png)
Uniramous
[
](/wiki/File:20211214_arthropod_biramous_arthropodized_appendage_morphology_en.png)
Biramous
Generalized external morphology of uniramous and biramous appendages
The appendages of arthropods may be either **biramous** or **uniramous** . A
uniramous limb comprises a single series of segments attached end-to-end. A
biramous limb, however, branches into two, and each branch consists of a
series of segments attached end-to-end.
The external branch (ramus) of the appendages of [ crustaceans
](/wiki/Crustaceans "Crustaceans") is known as the **exopod** or **exopodite**
, while the internal branch is known as the **endopod** or **endopodite** .
Other structures aside from the latter two are termed **exites** (outer
structures) and **endites** (inner structures). Exopodites can be easily
distinguished from exites by the possession of internal musculature. The
exopodites can sometimes be missing in some crustacean groups ( [ amphipods
](/wiki/Amphipod "Amphipod") and [ isopods ](/wiki/Isopod "Isopod") ), and
they are completely absent in insects. [5]
The legs of [ insects ](/wiki/Insect "Insect") and [ myriapods
](/wiki/Myriapoda "Myriapoda") are uniramous. In crustaceans, the first
antennae are uniramous, but the second antennae are biramous, as are the legs
in most species.
For a time, possession of uniramous limbs was believed to be a shared, [
derived character ](/wiki/Cladistics "Cladistics") , so uniramous arthropods
were grouped into a taxon called [ Uniramia ](/wiki/Uniramia "Uniramia") . It
is now believed that several groups of arthropods evolved uniramous limbs
independently from ancestors with biramous limbs, so this taxon is no longer
used.
## Chelicerata [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=2 "Edit section:
Chelicerata") ]
See also: [ Spider anatomy ](/wiki/Spider_anatomy "Spider anatomy") and [
Glossary of spider terms ](/wiki/Glossary_of_spider_terms "Glossary of spider
terms")
[
](/wiki/File:Spider_external_anatomy_appendages_en.png) Diagram of a spider
leg and pedipalp – the pedipalp has one fewer segment
[ Arachnid ](/wiki/Arachnid "Arachnid") legs differ from those of insects by
the addition of two segments on either side of the tibia, the patella between
the femur and the tibia, and the metatarsus (sometimes called basitarsus)
between the tibia and the tarsus (sometimes called telotarsus), making a total
of seven segments.
The tarsus of spiders have claws at the end as well as a hook that helps with
web-spinning. Spider legs can also serve sensory functions, with hairs that
serve as touch receptors, as well as an organ on the tarsus that serves as a
humidity receptor, known as the [ tarsal organ
](/wiki/Glossary_of_spider_terms#tarsal_organ "Glossary of spider terms") .
[6]
The situation is identical in [ scorpions ](/wiki/Scorpion "Scorpion") , but
with the addition of a pre-tarsus beyond the tarsus. The claws of the scorpion
are not truly legs, but are [ pedipalps ](/wiki/Pedipalp "Pedipalp") , a
different kind of [ appendage ](/wiki/Appendage "Appendage") that is also
found in spiders and is specialised for predation and mating.
In _[ Limulus ](/wiki/Horseshoe_crab "Horseshoe crab") _ , there are no
metatarsi or pretarsi, leaving six segments per leg.
## Crustacea [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=3 "Edit section:
Crustacea") ]
[
 ](/wiki/File:Crustaceanleg.jpg) The leg of a [ squat
lobster ](/wiki/Squat_lobster "Squat lobster") , showing the segments; the
ischium and merus are fused in many [ decapods ](/wiki/Decapoda "Decapoda")
The legs of [ crustaceans ](/wiki/Crustacean "Crustacean") are divided
primitively into seven segments, which do not follow the naming system used in
the other groups. They are: coxa, basis, ischium, merus, carpus, propodus, and
dactylus. In some groups, some of the limb segments may be fused together. The
claw ( [ chela ](/wiki/Chela_\(organ\) "Chela \(organ\)") ) of a lobster or
crab is formed by the articulation of the dactylus against an outgrowth of the
propodus. Crustacean limbs also differ in being biramous, whereas all other
extant arthropods have uniramous limbs.
## Myriapoda [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=4 "Edit section:
Myriapoda") ]
[
](/wiki/File:Scutigera_coleoptrata_205306445.jpg) Seven-segmented legs of _[
Scutigera coleoptrata ](/wiki/Scutigera_coleoptrata "Scutigera coleoptrata") _
[ Myriapods ](/wiki/Myriapod "Myriapod") ( [ millipedes ](/wiki/Millipede
"Millipede") , [ centipedes ](/wiki/Centipede "Centipede") and their
relatives) have seven-segmented walking legs, comprising coxa, trochanter,
prefemur, femur, tibia, tarsus, and a tarsal claw. Myriapod legs show a
variety of modifications in different groups. In all centipedes, the first
pair of legs is modified into a pair of venomous fangs called forcipules. In
most millipedes, one or two pairs of walking legs in adult males are modified
into sperm-transferring structures called [ gonopods
](/wiki/Gonopod_\(millipedes\) "Gonopod \(millipedes\)") . In some millipedes,
the first leg pair in males may be reduced to tiny hooks or stubs, while in
others the first pair may be enlarged.
## Insects [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=5 "Edit section:
Insects") ]
[
](/wiki/File:Tettigoniidae_Zabalius_aridus_True_Leaf_Katydid_2012_06_04_6713.JPG)
_[ Zabalius ](/wiki/Zabalius "Zabalius") aridus _ showing full leg anatomy,
including plantulae under each tarsomere
See also: [ Insect morphology ](/wiki/Insect_morphology "Insect morphology")
Insects and their relatives are hexapods, having six legs, connected to the [
thorax ](/wiki/Thorax_\(insect_anatomy\) "Thorax \(insect anatomy\)") , each
with five components. In order from the body they are the coxa, trochanter,
femur, tibia, and tarsus. Each is a single segment, except the tarsus which
can be from three to seven segments, each referred to as a _tarsomere_ .
Except in species in which legs have been lost or become vestigial through
evolutionary adaptation, adult insects have six legs, one pair attached to
each of the three segments of the thorax. They have paired appendages on some
other segments, in particular, [ mouthparts ](/wiki/Insect_mouthparts "Insect
mouthparts") , [ antennae ](/wiki/Antenna_\(biology\) "Antenna \(biology\)")
and [ cerci ](/wiki/Cercus "Cercus") , all of which are derived from paired
legs on each segment of some [ common ancestor ](/wiki/Onychophora#Evolution
"Onychophora") .
Some [ larval ](/wiki/Larva "Larva") insects do however have extra walking
legs on their abdominal segments; these extra legs are called [ prolegs
](/wiki/Proleg "Proleg") . They are found most frequently on the larvae of
moths and sawflies. Prolegs do not have the same structure as modern adult
insect legs, and there has been a great deal of debate as to whether they are
homologous with them. [7] Current evidence suggests that they are indeed
homologous up to a very primitive stage in their embryological development,
[8] but that their emergence in modern insects was not homologous between the
[ Lepidoptera ](/wiki/Lepidoptera "Lepidoptera") and [ Symphyta ](/wiki/Sawfly
"Sawfly") . [9] Such concepts are pervasive in current interpretations of
phylogeny. [10]
In general, the legs of larval insects, particularly in the [ Endopterygota
](/wiki/Endopterygota "Endopterygota") , vary more than in the adults. As
mentioned, some have prolegs as well as "true" thoracic legs. Some have no
externally visible legs at all (though they have internal rudiments that
emerge as adult legs at the final [ ecdysis ](/wiki/Ecdysis "Ecdysis") ).
Examples include the maggots of [ flies ](/wiki/Diptera "Diptera") or grubs of
[ weevils ](/wiki/Curculionidae "Curculionidae") . In contrast, the larvae of
other [ Coleoptera ](/wiki/Coleoptera "Coleoptera") , such as the [
Scarabaeidae ](/wiki/Scarabaeidae "Scarabaeidae") and [ Dytiscidae
](/wiki/Dytiscidae "Dytiscidae") have thoracic legs, but no prolegs. Some
insects that exhibit [ hypermetamorphosis ](/wiki/Hypermetamorphosis
"Hypermetamorphosis") begin their metamorphosis as [ planidia
](/wiki/Planidium "Planidium") , specialised, active, legged larvae, but they
end their larval stage as legless maggots, for example the [ Acroceridae
](/wiki/Acroceridae "Acroceridae") .
Among the [ Exopterygota ](/wiki/Exopterygota "Exopterygota") , the legs of
larvae tend to resemble those of the adults in general, except in adaptations
to their respective modes of life. For example, the legs of most immature [
Ephemeroptera ](/wiki/Mayfly "Mayfly") are adapted to scuttling beneath
underwater stones and the like, whereas the adults have more gracile legs that
are less of a burden during flight. Again, the young of the [ Coccoidea
](/wiki/Scale_insect "Scale insect") are called "crawlers" and they crawl
around looking for a good place to feed, where they settle down and stay for
life. Their later [ instars ](/wiki/Instar "Instar") have no functional legs
in most species. Among the [ Apterygota ](/wiki/Apterygota "Apterygota") , the
legs of immature specimens are in effect smaller versions of the adult legs.
[ _[ citation needed ](/wiki/Wikipedia:Citation_needed "Wikipedia:Citation
needed") _ ]
### Fundamental morphology of insect legs [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=6 "Edit section:
Fundamental morphology of insect legs") ]
[  ](/wiki/File:InsectLeg.svg) Diagram of a typical insect leg
A representative insect leg, such as that of a [ housefly ](/wiki/Housefly
"Housefly") or [ cockroach ](/wiki/Cockroach "Cockroach") , has the following
parts, in sequence from most [ proximal ](/wiki/Anatomical_terms_of_location
"Anatomical terms of location") to most [ distal
](/wiki/Anatomical_terms_of_location "Anatomical terms of location") :
* coxa
* trochanter
* femur
* tibia
* tarsus
* pretarsus.
Associated with the leg itself there are various [ sclerites ](/wiki/Sclerite
"Sclerite") around its base. Their functions are [ articular
](https://en.wiktionary.org/wiki/articular "wiktionary:articular") and have to
do with how the leg attaches to the main exoskeleton of the insect. Such
sclerites differ considerably between unrelated insects. [7]
#### Coxa [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=7 "Edit section: Coxa")
]
The coxa is the proximal segment and functional base of the leg. It
articulates with the [ pleuron ](/wiki/Pleuron_\(insect_anatomy\) "Pleuron
\(insect anatomy\)") and associated sclerites of its thoracic segment, and in
some species it articulates with the edge of the sternite as well. The
homologies of the various basal sclerites are open to debate. Some authorities
suggest that they derive from an ancestral subcoxa. In many species, the coxa
has two lobes where it articulates with the pleuron. The posterior lobe is the
[ meron ](/wiki/Insect_morphology "Insect morphology") which is usually the
larger part of the coxa. A meron is well developed in Periplaneta, the
Isoptera, Neuroptera and Lepidoptera.
#### Trochanter [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=8 "Edit section:
Trochanter") ]
The trochanter articulates with the coxa but usually is attached rigidly to
the femur. In some insects, its appearance may be confusing; for example it
has two subsegments in the Odonata. In parasitic Hymenoptera, the base of the
femur has the appearance of a second trochanter.
#### Femur [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=9 "Edit section:
Femur") ]
[
](/wiki/File:Acanthacris_ruficornis_Acrididae_IMG_2127s.jpg) _[ Acanthacris
](/wiki/Acanthacris "Acanthacris") ruficornis _ , legs saltatorial, femora
with [ bipennate muscle ](/wiki/Bipennate_muscle "Bipennate muscle")
attachments, spines on tibiae painfully effective in a defensive kick
In most insects, the femur is the largest region of the leg; it is especially
conspicuous in many insects with [ saltatorial
](/wiki/Glossary_of_entomology_terms "Glossary of entomology terms") legs
because the typical leaping mechanism is to straighten the joint between the
femur and the tibia, and the femur contains the necessary massive [ bipennate
](/wiki/Bipennate_muscle "Bipennate muscle") musculature.
#### Tibia [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=10 "Edit section:
Tibia") ]
The tibia is the fourth section of the typical insect leg. As a rule, the
tibia of an insect is slender in comparison to the femur, but it generally is
at least as long and often longer. Near the distal end, there is generally a
tibial spur, often two or more. In the [ Apocrita ](/wiki/Apocrita "Apocrita")
, the tibia of the foreleg bears a large apical spur that fits over a
semicircular gap in the first segment of the tarsus. The gap is lined with
comb-like bristles, and the insect cleans its antennae by drawing them
through.
#### Tarsus [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=11 "Edit section:
Tarsus") ]
[
 ](/wiki/File:Pegesimallus_sp_robberfly.jpg)
Robber fly ( [ Asilidae ](/wiki/Asilidae "Asilidae") ), showing tarsomeres and
pretarsi with ungues, pulvilli and empodia
See also: [ Tarsal formula ](/wiki/Tarsal_formula "Tarsal formula")
The ancestral tarsus was a single segment and in the extant [ Protura
](/wiki/Protura "Protura") , [ Diplura ](/wiki/Diplura "Diplura") and certain
insect larvae the tarsus also is single-segmented. Most modern insects have
tarsi divided into subsegments (tarsomeres), usually about five. The actual
number varies with the [ taxon ](/wiki/Taxon "Taxon") , which may be useful
for diagnostic purposes. For example, the [ Pterogeniidae
](/wiki/Pterogeniidae "Pterogeniidae") characteristically have 5-segmented
fore- and mid-tarsi, but 4-segmented hind tarsi, whereas the [ Cerylonidae
](/wiki/Cerylonidae "Cerylonidae") have four tarsomeres on each tarsus.
The distal segment of the typical insect leg is the pretarsus. In the [
Collembola ](/wiki/Springtail "Springtail") , Protura and many insect larvae,
the pretarsus is a single claw. On the pretarsus most insects have a pair of
claws ( [ _ungues_ , singular _unguis_
](/wiki/Glossary_of_entomology_terms#unguis "Glossary of entomology terms") ).
Between the ungues, a median unguitractor plate supports the pretarsus. The
plate is attached to the [ apodeme ](/wiki/Exoskeleton "Exoskeleton") of the
flexor muscle of the ungues. In the [ Neoptera ](/wiki/Neoptera "Neoptera") ,
the parempodia are a symmetrical pair of structures arising from the outside
(distal) surface of the unguitractor plate between the claws. [11] It is
present in many Hemiptera and almost all [ Heteroptera ](/wiki/Heteroptera
"Heteroptera") . [11] Usually, the parempodia are bristly (setiform), but in
a few species they are fleshy. [12] Sometimes the parempodia are reduced in
size so as to almost disappear. [13] Above the unguitractor plate, the
pretarsus expands forward into a median lobe, the **arolium** .
[
](/wiki/File:Embia_major_female_front_leg_showing_enlarged_tarsomere.jpg) [
Webspinner ](/wiki/Webspinner "Webspinner") , _[ Embia major
](/w/index.php?title=Embia_major&action=edit&redlink=1 "Embia major \(page
does not exist\)") _ , front leg showing enlarged tarsomere, which contains
the silk-spinning organs
Webspinners ( [ Embioptera ](/wiki/Embioptera "Embioptera") ) have an enlarged
basal tarsomere on each of the front legs, containing the [ silk ](/wiki/Silk
"Silk") -producing glands. [14]
Under their pretarsi, members of the [ Diptera ](/wiki/Diptera "Diptera")
generally have paired lobes or pulvilli, meaning "little cushions". There is a
single pulvillus below each unguis. The pulvilli often have an arolium between
them or otherwise a median bristle or **empodium** , meaning the meeting place
of the pulvilli. On the underside of the tarsal segments, there frequently are
pulvillus-like organs or **plantulae** . The arolium, plantulae and pulvilli
are adhesive organs enabling their possessors to climb smooth or steep
surfaces. They all are outgrowths of the exoskeleton and their cavities
contain blood. Their structures are covered with tubular tenent hairs, the
apices of which are moistened by a glandular secretion. The organs are adapted
to apply the hairs closely to a smooth surface so that adhesion occurs through
surface molecular forces. [7] [15]
Insects control the ungues through muscle tension on a long tendon, the
"retractor unguis" or "long tendon". In insect models of locomotion and motor
control, such as _[ Drosophila ](/wiki/Drosophila_melanogaster "Drosophila
melanogaster") _ ( [ Diptera ](/wiki/Diptera "Diptera") ), [ locusts
](/wiki/Locust "Locust") ( [ Acrididae ](/wiki/Acrididae "Acrididae") ), or
stick insects ( [ Phasmatodea ](/wiki/Phasmatodea "Phasmatodea") ), the long
tendon courses through the tarsus and tibia before reaching the femur. Tension
on the long tendon is controlled by two muscles, one in the femur and one in
the tibia, which can operate differently depending on how the leg is bent.
Tension on the long tendon controls the claw, but also bends the tarsus and
likely affects its stiffness during walking. [16]
### Variations in functional anatomy of insect legs [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=12 "Edit section:
Variations in functional anatomy of insect legs") ]
[
](/wiki/File:Starr_020615-0037_Erythrina_sandwicensis.jpg) Bruchine with
powerful femora used for escape from hard-shelled seed
The typical thoracic leg of an adult insect is adapted for running, rather
than for digging, leaping, swimming, predation, or other similar activities.
The legs of most [ cockroaches ](/wiki/Cockroach "Cockroach") are good
examples. However, there are many specialized adaptations, including:
* The forelegs of the [ Gryllotalpidae ](/wiki/Mole_cricket "Mole cricket") and some [ Scarabaeidae ](/wiki/Scarabaeidae "Scarabaeidae") are adapted to burrowing in earth.
* The forelegs of the [ Mantispidae ](/wiki/Mantispidae "Mantispidae") , [ Mantodea ](/wiki/Mantodea "Mantodea") , and [ Phymatinae ](/wiki/Phymatinae "Phymatinae") are adapted to seizing and holding prey in one way, while those of the [ Gyrinidae ](/wiki/Gyrinidae "Gyrinidae") are long and adapted for grasping food or prey in quite a different way.
* The forelegs of some butterflies, such as many [ Nymphalidae ](/wiki/Nymphalidae "Nymphalidae") , are reduced so greatly that only two pairs of functional walking legs remain.
* In most [ Orthoptera ](/wiki/Orthoptera "Orthoptera") , the hind legs are [ saltatorial ](/wiki/Saltatorial "Saltatorial") ; they have heavily bipinnately muscled femora and straight, long tibiae adapted to leaping and to some extent to defence by kicking. [ Flea beetles ](/wiki/Flea_beetle "Flea beetle") also have powerful hind femora that enable them to leap spectacularly.
* Other beetles with spectacularly muscular hind femora may not be saltatorial at all, but very clumsy; for example, particular species of [ Bruchinae ](/wiki/Bruchinae "Bruchinae") use their swollen hind legs for forcing their way out of the hard-shelled seeds of plants such as _[ Erythrina ](/wiki/Erythrina "Erythrina") _ in which they grew to adulthood.
* The legs of the [ Odonata ](/wiki/Odonata "Odonata") , the [ dragonflies ](/wiki/Dragonflies "Dragonflies") and [ damselflies ](/wiki/Damselflies "Damselflies") , are adapted for seizing prey that the insects feed on while flying or while sitting still on a plant; they are nearly incapable of using them for walking. [7]
* The majority of aquatic insects use their legs only for swimming, though many species of immature insects swim by other means such as by wriggling, undulating, or expelling water in jets.
[
](/wiki/File:Arthropod_segment_Hox_gene_expression.svg) Expression of [ Hox
genes ](/wiki/Hox_gene "Hox gene") in the [ body segments
](/wiki/Segmentation_\(biology\) "Segmentation \(biology\)") of different
groups of [ arthropod ](/wiki/Arthropod "Arthropod") , as traced by [
evolutionary developmental biology ](/wiki/Evolutionary_developmental_biology
"Evolutionary developmental biology") . The [ Hox genes ](/wiki/Hox_gene "Hox
gene") 7, 8, and 9 correspond in these groups but are shifted (by [
heterochrony ](/wiki/Heterochrony "Heterochrony") ) by up to three segments.
Segments with maxillopeds have Hox gene 7. Fossil [ trilobites
](/wiki/Trilobite "Trilobite") probably had three body regions, each with a
unique combination of Hox genes.
## Evolution and homology of arthropod legs [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=13 "Edit section:
Evolution and homology of arthropod legs") ]
The embryonic body segments ( [ somites ](/wiki/Somite "Somite") ) of
different [ arthropods ](/wiki/Arthropod "Arthropod") taxa have diverged from
a simple body plan with many similar appendages which are serially homologous,
into a variety of body plans with fewer segments equipped with specialised
appendages. [17] The homologies between these have been discovered by
comparing [ genes ](/wiki/Gene "Gene") in [ evolutionary developmental biology
](/wiki/Evolutionary_developmental_biology "Evolutionary developmental
biology") . [18]
[ Somite ](/wiki/Somite "Somite")
(body
segment) | [ Trilobite ](/wiki/Trilobite "Trilobite")
( [ Trilobitomorpha ](/wiki/Trilobitomorpha "Trilobitomorpha") )
[
](/wiki/File:202003_Trilobite.svg) | [ Spider ](/wiki/Spider "Spider")
( [ Chelicerata ](/wiki/Chelicerata "Chelicerata") )
[
](/wiki/File:202201_Common_house_spider.svg) | [ Centipede ](/wiki/Centipede
"Centipede")
( [ Myriapoda ](/wiki/Myriapoda "Myriapoda") )
[
](/wiki/File:Scolopendra_subspinipes_japonica_\(no_background\).png) | [
Insect ](/wiki/Insect "Insect")
( [ Hexapoda ](/wiki/Hexapoda "Hexapoda") )
[
](/wiki/File:202101_Chrysodeixis_eriosoma.svg) | [ Shrimp ](/wiki/Shrimp
"Shrimp")
( [ Crustacea ](/wiki/Crustacea "Crustacea") )
[
](/wiki/File:202112_Japanese_tiger_prawn.svg)
---|---|---|---|---|---
1 | antennae | [ chelicerae ](/wiki/Chelicerae "Chelicerae") (jaws and
fangs) | antennae | antennae | 1st antennae
2 | 1st legs | [ pedipalps ](/wiki/Pedipalps "Pedipalps") | \- | \- |
2nd antennae
3 | 2nd legs | 1st legs | [ mandibles
](/wiki/Mandible_\(arthropod_mouthpart\) "Mandible \(arthropod mouthpart\)") |
mandibles | mandibles (jaws)
4 | 3rd legs | 2nd legs | 1st [ maxillae
](/wiki/Maxilla_\(arthropod_mouthpart\) "Maxilla \(arthropod mouthpart\)") |
1st maxillae | 1st maxillae
5 | 4th legs | 3rd legs | 2nd maxillae | 2nd maxillae | 2nd maxillae
6 | 5th legs | 4th legs | collum (no legs) | 1st legs | 1st legs
7 | 6th legs | \- | 1st legs | 2nd legs | 2nd legs
8 | 7th legs | \- | 2nd legs | 3rd legs | 3rd legs
9 | 8th legs | \- | 3rd legs | \- | 4th legs
10 | 9th legs | \- | 4th legs | \- | 5th legs
### Leg modification classifications [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=14 "Edit section: Leg
modification classifications") ]
* [ Fossorial ](/wiki/Fossorial "Fossorial") legs are modified for [ digging ](/wiki/Digging "Digging") and [ burrowing ](/wiki/Burrow "Burrow") . For example: [ mole crickets ](/wiki/Mole_cricket "Mole cricket") have fossorial forelegs
* [ Saltatorial ](/wiki/Saltatorial "Saltatorial") legs are modified for [ jumping ](/wiki/Jumping "Jumping") and leaping. For example: many [ orthopterans ](/wiki/Orthoptera "Orthoptera") have saltatory hindlegs
* Natatorial legs are modified for [ swimming ](/wiki/Aquatic_locomotion "Aquatic locomotion") . For example: [ whirligig beetles ](/wiki/Whirligig_beetle "Whirligig beetle") have natatorial mesothoracic and metathoracic legs
* [ Cursorial ](/wiki/Cursorial "Cursorial") legs are modified for [ running ](/wiki/Terrestrial_locomotion#Legged_locomotion "Terrestrial locomotion") . For example: lots of [ cockroaches ](/wiki/Cockroach "Cockroach") have very sensitive cursorial legs
* [ Raptorial ](/wiki/Raptorial "Raptorial") legs are modified for [ grasping ](/wiki/Grasp "Grasp") , usually a hunting adaptation. For example: [ mantids ](/wiki/Mantidae "Mantidae") use their raptorial forelegs to hunt
## See also [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=15 "Edit section: See
also") ]
* [ Limb ](/wiki/Limb_\(anatomy\) "Limb \(anatomy\)")
* [ Tentacle ](/wiki/Tentacle "Tentacle")
* [ Tube foot ](/wiki/Tube_foot "Tube foot")
## References [ [ edit
](/w/index.php?title=Arthropod_leg&action=edit§ion=16 "Edit section:
References") ]
1. ** ^ ** Kukalova-Peck, J. (1992). "The "Uniramia" do not exist - the ground plan of the Pterygota as revealed by Permian Diaphanopterodea from Russia (Insecta, Paleodictyopteroidea)". _Canadian Journal of Zoology_ . **70** (2): 236–255. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1139/z92-037 ](https://doi.org/10.1139%2Fz92-037) .
2. ** ^ ** Fryer, G. (1996). [ "Reflections on arthropod evolution" ](https://doi.org/10.1111%2Fj.1095-8312.1996.tb01659.x) . _Biol. J. Linn. Soc_ . **58** (1): 1–55. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1111/j.1095-8312.1996.tb01659.x ](https://doi.org/10.1111%2Fj.1095-8312.1996.tb01659.x) .
3. ** ^ ** [ Schram, F. R. ](/wiki/Frederick_Schram "Frederick Schram") & S. Koenemann (2001). "Developmental genetics and arthropod evolution: part I, on legs". _Evolution & Development _ . **3** (5): 343–354. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1046/j.1525-142X.2001.01038.x ](https://doi.org/10.1046%2Fj.1525-142X.2001.01038.x) . [ PMID ](/wiki/PMID_\(identifier\) "PMID \(identifier\)") [ 11710766 ](https://pubmed.ncbi.nlm.nih.gov/11710766) . [ S2CID ](/wiki/S2CID_\(identifier\) "S2CID \(identifier\)") [ 25997101 ](https://api.semanticscholar.org/CorpusID:25997101) .
4. ** ^ ** Pat Willmer; Graham Stone; Ian Johnston (12 March 2009). [ _Environmental Physiology of Animals_ ](https://books.google.com/books?id=r9gvbjRFyRgC&pg=PA329) . John Wiley & Sons. p. 329. [ ISBN ](/wiki/ISBN_\(identifier\) "ISBN \(identifier\)") [ 978-1-4443-0922-5 ](/wiki/Special:BookSources/978-1-4443-0922-5 "Special:BookSources/978-1-4443-0922-5") .
5. ** ^ ** Geoff A. Boxshall & Damià Jaume (2009). [ "Exopodites, Epipodites and Gills in Crustaceans" ](https://research.nhm.org/pdfs/31363/31363.pdf) (PDF) . _Arthropod Systematics & Phylogeny _ . **67** (2). Museum für Tierkunde Dresden: 229–254. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.3897/asp.67.e31699 ](https://doi.org/10.3897%2Fasp.67.e31699) . [ Archived ](https://web.archive.org/web/20190426152013/http://www.arthropod-systematics.de/ASP_67_2/ASP_67_2_Boxshall_229-254.pdf) (PDF) from the original on 2019-04-26 . Retrieved 2012-01-14 .
6. ** ^ ** Pechmann, Matthias (November 2010). [ "Patterning mechanisms and morphological diversity of spider appendages and their importance for spider evolution" ](https://www.sciencedirect.com/science/article/pii/S1467803910000551) . _Arthropod Structure & Development _ . **39** (6): 453–467. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1016/j.asd.2010.07.007 ](https://doi.org/10.1016%2Fj.asd.2010.07.007) . [ PMID ](/wiki/PMID_\(identifier\) "PMID \(identifier\)") [ 20696272 ](https://pubmed.ncbi.nlm.nih.gov/20696272) . Retrieved 20 August 2020 .
7. ^ _**a** _ _**b** _ _**c** _ _**d** _ Richards, O. W.; Davies, R.G. (1977). _Imms' General Textbook of Entomology: Volume 1: Structure, Physiology and Development Volume 2: Classification and Biology_ . Berlin: Springer. [ ISBN ](/wiki/ISBN_\(identifier\) "ISBN \(identifier\)") [ 0-412-61390-5 ](/wiki/Special:BookSources/0-412-61390-5 "Special:BookSources/0-412-61390-5") .
8. ** ^ ** Panganiban, Grace; Nagy, Lisa; [ Carroll, Sean B. ](/wiki/Sean_B._Carroll "Sean B. Carroll") (1994). "The role of the Distal-less gene in the development and evolution of insect limbs". _Current Biology_ . **4** (8): 671–675. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1016/S0960-9822(00)00151-2 ](https://doi.org/10.1016%2FS0960-9822%2800%2900151-2) . [ PMID ](/wiki/PMID_\(identifier\) "PMID \(identifier\)") [ 7953552 ](https://pubmed.ncbi.nlm.nih.gov/7953552) . [ S2CID ](/wiki/S2CID_\(identifier\) "S2CID \(identifier\)") [ 22980014 ](https://api.semanticscholar.org/CorpusID:22980014) .
9. ** ^ ** Suzuki, Y; Palopoli, MF (Oct 2001). "Evolution of insect abdominal appendages: are prolegs homologous or convergent traits?". _Dev Genes Evol_ . **211** (10): 486–92. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1007/s00427-001-0182-3 ](https://doi.org/10.1007%2Fs00427-001-0182-3) . [ PMID ](/wiki/PMID_\(identifier\) "PMID \(identifier\)") [ 11702198 ](https://pubmed.ncbi.nlm.nih.gov/11702198) . [ S2CID ](/wiki/S2CID_\(identifier\) "S2CID \(identifier\)") [ 1163446 ](https://api.semanticscholar.org/CorpusID:1163446) .
10. ** ^ ** Galis, Frietson (1996). "The evolution of insects and vertebrates: homeobox genes and homology". _Trends in Ecology & Evolution _ . **11** (10): 402–403. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1016/0169-5347(96)30038-4 ](https://doi.org/10.1016%2F0169-5347%2896%2930038-4) . [ PMID ](/wiki/PMID_\(identifier\) "PMID \(identifier\)") [ 21237897 ](https://pubmed.ncbi.nlm.nih.gov/21237897) .
11. ^ _**a** _ _**b** _ Friedemann, Katrin; Spangenberg, Rico; Yoshizawa, Kazunor; Beutel, Rolf G. (2013). [ "Evolution of attachment structures in the highly diverse Acercaria (Hexapoda)" ](https://web.archive.org/web/20140125061403/http://insect3.agr.hokudai.ac.jp/psoco-web/pdf/2013clad.pdf) (PDF) . _Cladistics_ . **30** (2): 170–201. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1111/cla.12030 ](https://doi.org/10.1111%2Fcla.12030) . [ PMID ](/wiki/PMID_\(identifier\) "PMID \(identifier\)") [ 34781597 ](https://pubmed.ncbi.nlm.nih.gov/34781597) . [ S2CID ](/wiki/S2CID_\(identifier\) "S2CID \(identifier\)") [ 86195785 ](https://api.semanticscholar.org/CorpusID:86195785) . Archived from [ the original ](http://insect3.agr.hokudai.ac.jp/psoco-web/pdf/2013clad.pdf) (PDF) on 25 January 2014 . Retrieved 25 January 2014 .
12. ** ^ ** Schuh, Randall T. & Slater, James Alexander (1995). _True Bugs of the World (Hemiptera:Heteroptera): Classification and Natural History_ . Ithaca, New York: Cornell University Press. p. [ 46 ](https://books.google.com/books?id=wmSc-2KDmZ4C&pg=PA46) . [ ISBN ](/wiki/ISBN_\(identifier\) "ISBN \(identifier\)") [ 978-0-8014-2066-5 ](/wiki/Special:BookSources/978-0-8014-2066-5 "Special:BookSources/978-0-8014-2066-5") .
13. ** ^ ** Goel, S. C. (1972). "Notes on the structure of the unguitractor plate in Heteroptera (Hemiptera)". _Journal of Entomology Series A, General Entomology_ . **46** (2): 167–173. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1111/j.1365-3032.1972.tb00124.x ](https://doi.org/10.1111%2Fj.1365-3032.1972.tb00124.x) .
14. ** ^ ** Ross, Edward S. (1991). "Embioptera". In Naumann, I. D.; Carne, P. B.; et al. (eds.). _The Insects of Australia. Volume 1_ (2 ed.). Melbourne University Press. pp. 405–409.
15. ** ^ ** Stanislav N Gorb. "Biological attachment devices: exploring nature's diversity for biomimetics Phil. _Trans. R. Soc. A_ 2008; 366(1870): 1557-1574 doi:10.1098/rsta.2007.2172 1471-2962
16. ** ^ ** RADNIKOW, G.; BÄSSLER, U. (1991-05-01). [ "Function of a Muscle Whose Apodeme Travels Through a Joint Moved by Other Muscles: Why the Retractor Unguis Muscle in Stick Insects is Tripartite and has no Antagonist" ](https://doi.org/10.1242/jeb.157.1.87) . _Journal of Experimental Biology_ . **157** (1): 87–99. [ doi ](/wiki/Doi_\(identifier\) "Doi \(identifier\)") : [ 10.1242/jeb.157.1.87 ](https://doi.org/10.1242%2Fjeb.157.1.87) . [ ISSN ](/wiki/ISSN_\(identifier\) "ISSN \(identifier\)") [ 0022-0949 ](https://www.worldcat.org/issn/0022-0949) .
17. ** ^ ** Novartis Foundation; Hall, Brian (2008). [ _Homology_ ](https://books.google.com/books?id=vptaNfbkd8sC&pg=PA29) . John Wiley. p. 29. [ ISBN ](/wiki/ISBN_\(identifier\) "ISBN \(identifier\)") [ 978-0-470-51566-2 ](/wiki/Special:BookSources/978-0-470-51566-2 "Special:BookSources/978-0-470-51566-2") .
18. ** ^ ** Brusca, R.C.; Brusca, G.J. (1990). [ _Invertebrates_ ](https://archive.org/details/invertebrates0000brus) . Sinauer Associates. p. [ 669 ](https://archive.org/details/invertebrates0000brus/page/669) .
* [  ](/wiki/File:Cercophonius_squama.jpg) [ Arthropods portal ](/wiki/Portal:Arthropods "Portal:Arthropods")
* [ v ](/wiki/Template:Locomotion "Template:Locomotion")
* [ t ](/wiki/Template_talk:Locomotion "Template talk:Locomotion")
* [ e ](/wiki/Special:EditPage/Template:Locomotion "Special:EditPage/Template:Locomotion")
[ Animal locomotion on land ](/wiki/Terrestrial_locomotion "Terrestrial
locomotion")
---
[ Gait ](/wiki/Gait "Gait") class |
| Legged |
* [ Arboreal locomotion ](/wiki/Arboreal_locomotion "Arboreal locomotion") ( [ Brachiation ](/wiki/Brachiation "Brachiation") )
* [ Hand-walking ](/wiki/Hand_walking "Hand walking")
* [ Jumping ](/wiki/Jumping "Jumping")
* [ Knuckle-walking ](/wiki/Knuckle-walking "Knuckle-walking")
* [ Running ](/wiki/Running "Running")
* [ Walking ](/wiki/Walking "Walking")
---|---
Legless |
* [ Concertina movement ](/wiki/Concertina_movement "Concertina movement")
* [ Undulatory locomotion ](/wiki/Undulatory_locomotion "Undulatory locomotion")
* [ Rectilinear locomotion ](/wiki/Rectilinear_locomotion "Rectilinear locomotion")
* [ Rolling ](/wiki/Rotating_locomotion_in_living_systems "Rotating locomotion in living systems")
* [ Sidewinding ](/wiki/Sidewinding "Sidewinding")
* [ Other modes ](/wiki/Terrestrial_locomotion#Limbless_locomotion "Terrestrial locomotion")
[ Anatomy ](/wiki/Anatomy "Anatomy") |
* [ Comparative foot morphology ](/wiki/Comparative_foot_morphology "Comparative foot morphology")
* Arthropod leg
* [ Digitigrade ](/wiki/Digitigrade "Digitigrade")
* [ Plantigrade ](/wiki/Plantigrade "Plantigrade")
* [ Unguligrade ](/wiki/Ungulate "Ungulate")
* [ Uniped ](/wiki/Unipedalism "Unipedalism")
* [ Biped ](/wiki/Bipedalism "Bipedalism") ( [ Facultative ](/wiki/Facultative_bipedalism "Facultative bipedalism") )
* [ Triped ](/wiki/Tripedalism "Tripedalism")
* [ Quadruped ](/wiki/Quadrupedalism "Quadrupedalism")
Specific |
* [ Canine gait ](/wiki/Canine_gait "Canine gait")
* [ Horse gait ](/wiki/Horse_gait "Horse gait")
* [ Human gait ](/wiki/Gait_\(human\) "Gait \(human\)")
* [ Animal locomotion on the water surface ](/wiki/Animal_locomotion_on_the_water_surface "Animal locomotion on the water surface")
* [ Fish locomotion ](/wiki/Fish_locomotion "Fish locomotion")
* [ Volant animals ](/wiki/Flying_and_gliding_animals "Flying and gliding animals")
Retrieved from " [
https://en.wikipedia.org/w/index.php?title=Arthropod_leg&oldid=1221090000
](https://en.wikipedia.org/w/index.php?title=Arthropod_leg&oldid=1221090000) "
[ Categories ](/wiki/Help:Category "Help:Category") :
* [ Arthropod morphology ](/wiki/Category:Arthropod_morphology "Category:Arthropod morphology")
* [ Animal locomotion ](/wiki/Category:Animal_locomotion "Category:Animal locomotion")
* [ Spider anatomy ](/wiki/Category:Spider_anatomy "Category:Spider anatomy")
* [ Trilobite anatomy ](/wiki/Category:Trilobite_anatomy "Category:Trilobite anatomy")
Hidden categories:
* [ Articles with short description ](/wiki/Category:Articles_with_short_description "Category:Articles with short description")
* [ Short description is different from Wikidata ](/wiki/Category:Short_description_is_different_from_Wikidata "Category:Short description is different from Wikidata")
* [ Pages using multiple image with auto scaled images ](/wiki/Category:Pages_using_multiple_image_with_auto_scaled_images "Category:Pages using multiple image with auto scaled images")
* [ All articles with unsourced statements ](/wiki/Category:All_articles_with_unsourced_statements "Category:All articles with unsourced statements")
* [ Articles with unsourced statements from December 2017 ](/wiki/Category:Articles_with_unsourced_statements_from_December_2017 "Category:Articles with unsourced statements from December 2017")
* This page was last edited on 27 April 2024, at 20:29 (UTC) .
* Text is available under the [ Creative Commons Attribution-ShareAlike License 4.0 ](//en.wikipedia.org/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License) [ ](//en.wikipedia.org/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License) ; additional terms may apply. By using this site, you agree to the [ Terms of Use ](//foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use) and [ Privacy Policy ](//foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy) . Wikipedia® is a registered trademark of the [ Wikimedia Foundation, Inc. ](//www.wikimediafoundation.org/) , a non-profit organization.
* [ Privacy policy ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy)
* [ About Wikipedia ](/wiki/Wikipedia:About)
* [ Disclaimers ](/wiki/Wikipedia:General_disclaimer)
* [ Contact Wikipedia ](//en.wikipedia.org/wiki/Wikipedia:Contact_us)
* [ Code of Conduct ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct)
* [ Developers ](https://developer.wikimedia.org)
* [ Statistics ](https://stats.wikimedia.org/#/en.wikipedia.org)
* [ Cookie statement ](https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement)
* [ Mobile view ](//en.m.wikipedia.org/w/index.php?title=Arthropod_leg&mobileaction=toggle_view_mobile)
* [  ](https://wikimediafoundation.org/)
* [  ](https://www.mediawiki.org/)
* Toggle limited content width
*[
pl.
]: plural form
*[
v
]: View this template
*[
t
]: Discuss this template
*[
e
]: Edit this template
| biology | 2777004 | https://sv.wikipedia.org/wiki/Stictopleurus%20punctatonervosus | Stictopleurus punctatonervosus | Stictopleurus punctatonervosus är en insektsart som först beskrevs av Johann August Ephraim Goeze 1778. Stictopleurus punctatonervosus ingår i släktet Stictopleurus, och familjen smalkantskinnbaggar. Arten är reproducerande i Sverige.
Bildgalleri
Källor
Externa länkar
Smalkantskinnbaggar
punctatonervosus | swedish | 1.452573 |
insescts_six_legs/Week2007a20Legspdf.txt | INSECT MORPHOLOGY - LEGS 1
* The fact that arthropods are and have been serially metameric animals from their very early beginnings has
provided an evolutionary platform from which great diversity has been achieved. The presence of similar
appendages on each of the metameres which were presumably primitively designed for walking has in great
part been responsible for the great diversity seen today.
* Today the segmental appendages serve many functions. Walking, swimming, jumping, carrying, digging, grasping,
feeding, etc.
* The most primitive arthropods known, the trilobites had segmental appendages which were fully segmented in
available fossils. Note the labrum over the mouth and the 18 pairs of segmental appendages (4+3+11)
which are all similar and apparently function for walking. The fossil record does not extend further back to
the trilobite ancestors to allow us a glimpse of how arthropod legs arrived at a primitively 8-segmented
condition. So, we must turn to embryology and comparative anatomy to gain insight into phylogenetic
relationships among the arthropods. We still will gain very little understanding into the phylogenetic
development of arthropod limbs.
* Embryological evidence shows that regardless of the final adult form, all arthropod appendages have the same
origin in the embryo, namely, from paired, lateroventral bud-like lobes of the body segments. Also, the
embryonic development of the legs in the arthropods is very similar to that seen in the onychophorans,
suggesting that they are homologous. The musculature of the 2 groups also supports their being
homologous.
* The leg is a tubular outgrowth of the body wall. Its movable sections are called podomeres, and are merely the
sclerotized parts of the tube, and the joints are short unsclerotized parts between them. Snodgrass equates
podomeres and podites, but this is no longer true. In fact, in later writings of Snodgrass he admits that there
is a difference. A podomere is simply a segment of a limb. A podite is a true segment of the limb that can
be recognized by have muscles inserted on the walls of the segment. A podite is a type of podomere. The
true segments may be subdivided into subsegments. This is especially true in the tarsus where up to 5
subsegments are recognized. These are more correctly called tarsomeres. The only known case where true
tarsal segments are known is in the male pycnogonid where individual tarsomeres are individually
musculated.
* To limit the movement at the intersegmental limb joint, the ends of the adjoining segments are specifically
articulated on each other. An articulation is usually formed by the extension of an articular process from
the base of the distal segment through the joint membrane and is received in a socket on the end of the
proximal segment. The hinge is sometimes vertical; sometimes horizontal and as in B, there may only be
one articulation. Articulations are generally absent between non-musculated subsegments, allowing free
movement in all directions.
* The joint between the coxa and the body wall may be monocondylic, dicondylic, or even more complicated. It
may articulate with any one of several small sclerites, with the pleura, and/or the sternum. The joint
between the coxa and the trochanter is always a dicondylic joint with motion restricted to a forward and
backward direction. The joint between the trochanter and the femur is usually fairly firmly attached or with
only a small amount of movement posible. The joint between the femur and the tibia is another dicondylic
joint similar to the coxo-trochanteral joint.
* The joints are named in a special way. When naming them use the more proximal part as the first part of a
compound adjective and the more distal part as the second part. The first part ends in "o" and the second
part in "al" as:
coxo-trochanteral joint, femoro-tibial, etc.
INSECT MORPHOLOGY - LEGS 2
* The primitive limb probably had 8 segments as in the trilobites. Zoologists give special names to them not often
used by entomologists.
* The limb can first be divided into a basis (the coxopodite) and a distal arm, the telopodite.
1. COXOpodite Coxa + subcoxa
2. BASIpodite 1st trochanter
3. ISCHIOpodite 2nd trochanter
4. MEROpodite femur
5. patella patella
6. CARPOpodite tibia
7. PROpodite tarsus
8. DACTYLOpodite pretarsus
* TRILOBITES - Fig. 19A. All segments about equal except for the small 3-clawed pretarsus. The patella is
present in trilobites.
* EURYPTERIDS - Fig. 19B. The last 2 pairs of legs appear to be 9-segmented but two rings following coxa may
be subdivision because they are not present on other legs.
* PYCNOGONIDS - Fig. 19C. What appears to be a leg segment is part of the body wall. Three-clawed pretarsus
is present.
* SOME ARACHNIDS (SOLPUGIDS AND ACARINA) - Fig. 19D. Same 8 segments present. Second
trochanter may be reduced.
* OTHER ARACHNIDS (SCORPIONS AND MOST OTHERS) - Fig. 19E. Have only 7 segments by
elimination of one of the trochanters. The tarsus is subdivided to include 2 subsegments. The patella is
characteristically present in all Chelicerata, including Xiphosurida, which also has only one trochanter.
* MANDIBULATA - Figs. 19F-I. Typically lacks a patella, but 2 trochanters are present in most species.
Therefore the Crustacea (F) and myriapods typically have 7-segmented legs. The trochanters vary in size.
* The differentiation of the primitive arthropod leg into organs for purposes other than walking or running has been
due in large part to the development of outgrowths of various kinds from the outer and inner surfaces of the
limb segments. Outgrowths from the outer surface are called exites, outgrowths from the inner surface are
called endites. Coxal exites are always called epipodites regardless of their function. They can be seen in
trilobites where they probably served in respiration as gills (Figd. 19A, 21B in overhead).
* Crustacea, expecially larval forms, have an exite on the 2nd leg segment (basipodite or first trochanter) which is
always called an exopodite (Fig. 21A). The presence of the crustacean exopodite has led to this limb being
called biramous. In many crustaceans, these exopodites serve as temporary swimming organs. They are
often reduced in gnathal segments when the pleopods (swimming leg) of the adult assume a swimming
function. The pleopods usually retain the biramous form, but never have the structure or segmentation of
functional legs, suggesting that their growth is arrested at an early stage of development, if they ever were
functional legs.
* The distal parts of limbs may have endites as well. In the crustacea, a chela is formed by an endite process of the
tarsus (propodite) opposed to the movable pretarsus (dactylopodite) (Fig. 21L). In the scorpion, the
movable member of the chela is the tarsus. The tarsus and pretarsus are fused; the endite is formed from the
tibia (carpopodite) (Fig. 21K).
INSECT MORPHOLOGY - LEGS 3
* INSECTS - Fig. 19J. Insect legs are typically 6-segmented (coxa, trochanter, femur, tibia, tarsus, pretarsus)
usually having only one trochanter and lacking a patella. The tarsus is subdivided and there is typically a 2-
clawed pretarsus. A 2-segmented trochanter (only one is musculated) occurs in the Odonata and in some
Hymenoptera, but the second trochanter actually appears to be a part of the femur.
* Coxae - The first segment of the insect leg is the coxa. It may be variously shaped, but is often in the form of a
cone that articulates with the body wall proximally, and with the trochanter distally. The articulation with
the body wall may be singular (fig. 8.2a) - this allows for a lot of flexibility, but is not as strong. The
articulation may be dicondylic, one articulation with the body wall, and another with the trochantin (fig.
8.2b); this limits flexibility a little, but since the trochantin, itself, is flexibly articulated with the episternum,
there is still some freedom of movement. The coxa may have two articulations with the body wall, a pleural
articulation and a sternal articulation (fig. 8.2c) - this makes for a stronger joint, but limits articulation to
one plane of movement. Finally, in some groups, the hind coxae are fused to the body wall (Coleoptera:
Adephaga) or both the middle and hind coxae are fused to the body wall (Lepidoptera).
* Sometimes the basal portion of the coxae is subdivided from the rest of the coxa by a suture, the basicostal suture;
this suture forms an internal ridge that strengthens the basal area of the coxa for the above articulations.
The resulting narrow sclerite at the coxal base is called the basicoxite, in some cases, the basicoxite may
have a smaller anterior part, and a larger posterior part, this enlarged posterior part is called the meron.
* Trochanter - This is usually a small segment, it has a dicondylic articulation with the coxa which limits movement
to the vertical plane (fig. 81b). See above notes about double trochanters in Hymenoptera and Odonata.
* Femur - Often small in larval insects, but usually the largest and strongest leg segment in adult insects. It is
usually more or less fused with the trochanter, sometimes there is a little flexion between the two segments.
* Tibia - Often a long narrow segment, with a dicondylic articulation with the femur - moves in a vertical plane (fig.
8.1c). The proximal end of the tibia is often bent so that when the tibia is folded inward, it can lie up
against the femur.
* Tarsus - The tarsi comprise the foot or contact surface of the leg. The tarsus, in most insects, is subdivided into
from two to five tarsomeres, but never exceeds five. These tarsomeres are not true segments as they lack
individual musculature as seen in the other segments. The basal segment, the basitarsus, has a
monocondylic articulation with the tibia; the rest of the joints lack true articulatory structures, they are
freely moveable in the membranous joints. In a few groups, the tarsus is unsegmented and/or fused with the
tibia. A pad-like ventral surface or euplantula (sometimes called pulvilli) on the tarsal segments may
enhance the traction of the animal.
* Pretarsus - The pretarsus of most insects consists of a membranous base supporting a median lobe, the arolium,
and a pair of tarsal claws. The claws (sometimes called ungues) articulate with a median process of the
last tarsomere called the unguifer. There is a ventral plate, called the unguitractor, and between this plate
and the claws are small plates called auxilliae. There is no arolium in most Diptera, but rather a
membranous pulvillus arises from the base of each auxillia, while a median empodium arises from the
unguitractor (may be spine-like or lobe-like). In most insects, the tarsal claws are rather uniform in size and
shape, but in others one claw may be more highly developed than the other, and in some groups there is a
single claw.
* General Comments on Leg Musculature - Another way muscles can be categorized: extrinsic (arising from
outside the leg) and intrinsic (occurring totally within the leg, and running from one segment to the next).
The coxa is moved by extrinsic muscles, arising in the thorax. The remaining segments are moved by pairs
of antagonistic muscles in each segment. There may be extensor and flexor muscles, or levator and
depressor muscles. There are no muscles within the tarsus moving the tarsomeres. The pretarsus does have
INSECT MORPHOLOGY - LEGS 4
a depressor muscle, but no levator muscle; levation of the pretarsus results from the elasticity of the basal
parts. This depressor muscle is composed of small fibers arising in the femur and tibia which combine to
form a long apodeme that inserts onto the unguitractor plate.
* Specialized leg types and structures. I am not going over these. Like the different antennal types, I expect you
to already know the basic leg types (raptorial, natatorial, ambulatory, saltatorial, cursorial, fossorial,
etc.).
* Terms related to the movement of legs:
protraction - forward movement of the entire limb.
promotion - movement of the coxa resulting in protraction.
retraction - posterior movement of the entire limb.
remotion - movement of the coxa resulting in retraction.
adduction - movement towards the body, or midline of the body.
abduction - movement away from the body, or midline of the body.
levation - the raising of the leg or a part of the leg.
depression - the lowering of the leg or a part of the leg.
extension - an increase in the angle between two leg segments.
flexion - a decrease in the angle between two leg segments.
* Simple leg movement - At slower speeds, the legs may move in different patterns, but in general, and at higher
speeds, insects use an alternating tripod type of movement. By this I mean that the foreleg and hindleg on
one side of the body, and the middle leg on the other side of the body will all three be lifted and moved
forward at the same time. They then come to rest on the ground and the other three legs are lifted in moved
forward. This means that there are always three legs on the ground at a time, and in the shape of a triangle
or tripod - this is a fairly stable arrangement.
| biology | 1121602 | https://sv.wikipedia.org/wiki/Tibialis%20posterior | Tibialis posterior | Musculus tibialis posterior är en djupt liggande skelettmuskel belägen på baksidan av underbenet. Den har två huvudfunktioner: att böja foten nedåt, plantarflektion, och att vrida fotsulan inåt, inversion. Muskeln tar sitt ursprung från tre platser: den övre tredjedelen av fibulas bakre och inre sida, den övre delen av tibia, och membranet som skiljer fibula och tibia.
Muskeln sträcker sig längs underbenet och övergår i en sena som rundar den inre fotknölen, även kallad mediala malleolen. Denna sena delar upp sig i tre delar:
Den första delen fäster i os naviculare och den plantara delen av os cuneiforme mediale.
Den andra delen fäster i basen av de andra, tredje och fjärde metatarsalbenen, samt i de andra och tredje cuneiformebenen och i os cuboideum.
Den tredje och sista delen fäster i sustentaculum tali i calcaneus
Denna anatomiska struktur är känd som tarsaltunneln. Musculus tibialis posterior är en av sju muskler i underbenets bakre muskelfack (kompartment). De andra musklerna i detta kompartment är:
musculus gastrocnemius
flexor hallucis longus soleus
musculus plantaris
musculus popliteus
musculus flexor digitorum longus
musculus tibialis posterior.
Funktion
Musculus tibialis posterior och musculus tibialis anterior är de primära musklerna som inverterar foten. Denna rörelse äger huvudsakligen rum i två synovialleder: subtalarleden och de midtarsala lederna, som är de leder som förbinder mellanfotsbenen (metatarsalben) med fotens tarsalben. Musculus tibialis posterior, som löper längs baksidan av underbenet och foten, bidrar även till plantarflexion i samarbete med musculus gastrocnemius, musculus soleus och musculus plantaris.
Muskelns fäste under foten gör att den spelar en viktig roll i att upprätthålla det mediala längsgående fotvalvet. Detta valv är normalt högre än det laterala och stöds av följande tarsalben: calcaneus, talus, naviculare, de tre cuneiformebenen och de tre första metatarsalbenen.
Blodförsörjning
Musculus tibilais posterior får främst sin blodförsörjning från arteria tibialis posterior, som springer ur arteria poplitea. Arteria tibialis posteriors löper djupt inne i underbenets bakre kompartment och blodförsörjer alla muskler i området. Löper vidare runt den mediala malleolen och vidare ner under foten tillsammans med musculus tibilais posterior, musculur flexor digitorum, musculus flexor hallucis longus och nervus tibialis posterior.
Innervation
Musculus tibialis posterior får sin nervförsörjning av nervus tibialis. Olika benämningar används på denna nervstruktur, nervus tibialis är vanligast, men nervus tibialis posterior är också frekvent förekommande. Nervus tibialis springer ur ischiasnerven. Strax ovan knävecket, precis vid övre delen av fossa poplitea, förgrenar sig ischiasnerven i nervus tibialis och nervus peroneus communis. Nervus tibialis fortsätter ner i underbenet där den till slut rundar mediala malleolen (inre fotknölen), genom tarsaltunneln, och sedan löper in under foten och grenar upp sig i nervus plantaris medialis och nervus plantaris lateralis.
Skador
Överansträngningsskador kan uppstå i musculus tibialis posterior vid olika typer av aktiviteter som innebär hoppande och springande som exempelvis:
basket
löpning
tennis
fotboll
joggning.
Besvär med smärta från musculus tibialis posterior förkommer ofta tillsammans med olika förändringar av fotens mekanik. Initialt sker successivt tapp av det längsgående fotvalvet, vilket äventyrar fotens dynamiska stabilisatorer. Detta kan med tiden leda till nedsatt funktion och påfrestning på de passiva stabilisatorerna av bakre delen av foten (talus och calcaneus), vilket innefattar ligamentum calcaneonaviculalare, plantarfascian och plantara stödjande ligamentstrukturer. Vid detta tillstånd står ofta calcaneus i valgus samt främre delen av foten abduceras (vinklas utåt).
Åtgärder
Vid överansträngning av musculus tibialis posterior har ofta inlägg i skor god effekt. Inläggets syfte är att stötta det längsgående fotvalvet och på så sätt avlasta musculus tibialis posterior. Utöver inlägg kan stretch och övningar för denna muskel minska smärtan ytterligare.
Bildgalleri
Referenser
Skelettmuskler
nedre extremitetens anatomi | swedish | 0.521084 |
insescts_six_legs/S1467803908000650.txt | Skip to main contentSkip to article
Elsevier logo
Journals & Books
Search ScienceDirect
Search ScienceDirect
Article preview
Abstract
Introduction
Section snippets
References (54)
Cited by (19)
Elsevier
Arthropod Structure & Development
Volume 38, Issue 1, January 2009, Pages 16-30
Arthropod Structure & Development
Gimbals in the insect leg
Author links open overlay panelLeonid Frantsevich a, Weiying Wang b
Show more
Add to Mendeley
Share
Cite
https://doi.org/10.1016/j.asd.2008.06.002
Get rights and content
Abstract
We studied the common kinematic features of the coxa and trochanter in cursorial and raptorial legs, which are the short size of the podomers, predominantly monoaxial joints, and the approximate orthogonality of adjacent joint axes. The chain coxa-trochanter with its short elements and serial orthogonality of joint axes resembles the gimbals which combine versatility and tolerance to external perturbations.
The geometry of legs was studied in 23 insect species of 12 orders. Insects with monoaxial joints were selected. The joint between the trochanter and the femur (TFJ) is defined either by two vestigial condyles or by a straight anterior hinge. Direction of the joint axes in the two basal podomers was assessed by 3D measurements or by goniometry in two planes. Length of the coxa is <15% (mostly <8%) of the total length of the cursorial leg, that of the trochanter <10%. Angles between the proximal and distal joint axes in the middle coxa range from 124 to 84° (mean 97 ± 14°), in the trochanter (in all legs studied) from 125 to 72° (mean 90 ± 13°). Vectors of the distal axis in the coxa are concentrated about the normal to the plane defined by the proximal axis and the midpoint between the distal condyles. These vectors in the trochanter lie at various angles to the normal; angles are correlated with the direction of the TFJ relative to the femur. Range of reduction about the TFJ is over 60° in the foreleg of Ranatra linearis, Mantispa lobata and the hind leg in Carabus coriaceus (confirming observations of previous authors), 40–60° in the foreleg of Vespa crabro and in the middle one in Ammophila campestris, 10–30° in other studied specimens. The special role of the trochanter in autotomy and in active propulsion in some insect groups is discussed. The majority of insects possess small trochanters and slightly movable TFJs with the joint axis laying in the femur-tibia plane. We pose the hypothesis that the TFJ damps external forces, the vectors of which lie off the femur-tibia plane, the reductor muscle acting as a spring. Thus the TFJ contributes to dynamic stability of legged locomotion.
Introduction
Each textbook in entomology describes many types of leg specialization (saltatory, raptorial, swimming, etc.). However, the basic type, the cursorial one, lacks a detailed description. It is just described as the most common among insects and lacking evident specialization, besides attachment devices. We think that there are common kinematic features of two proximal podomers, the coxa and the trochanter, which are essential to understand the functional morphology of the ground plan of the insect leg. The first is the small size of both podomers. Secondly, the joints between the coxa and the trochanter as well as between the trochanter and the femur are hinges with one degree of rotational freedom; in many insects, at least in their middle and hind legs, the thoracico-coxal joint is also monoaxial: either it is bicondylic or the coxa rotates inside a cylindrical coxal cavity. Thirdly, in the case of monocondylic joints, the angle between the proximal and distal joint axis within each podomer is approximately 90°. Working these features for their limits, one obtains a kinematic chain with two elements of zero length and orthogonal disposition of serial joint axes; hence, three joint axes cross at the common point. Together they have three rotational degrees of freedom.
Such features characterize a spherical mechanism, a universal joint constructed by gimbals (Cardan transmission in a car, gyroscopic suspension in navigation devices). The gimbals have wide spatial versatility and are resistant to disturbances. A short coxa (or coxopodit, in crustaceans) was recognized as an analog of the universal joint (Chao, 1953, Hessler, 1982). The next short podomer, the trochanter, was usually neglected, and its functions in most insects remain enigmatic.
We studied 3D geometry of the coxa and trochanter in cursorial legs and demonstrate how closely they approach the ideal universal joint. We agree that the pair of basal podomers provides the advantage of kinematic versatility. Moreover, we suppose that the distal joint of this pair, namely the TFJ, facilitates dynamic stability, counteracting external disturbances the vectors of which lie out of the leg plane.
We selected insects of various orders, preferably of large size and with definite markers of the coxo-thoracical suspension. Among them were wingless firebrats, beetles, the stick insect, the desert ant. A winged sphecid wasp, Ammophila, and a muscid fly, Lispe, are known as agile walkers. Some insects possess trochanters of special shape and function: autotomizing, versatile (especially in raptorial legs) or apparently paired. Small insects were inspected only superficially, without 3D reconstruction. Middle legs were preferred as they are less specialized, compared to the front legs (often palpatory) or hind legs (sometimes saltatory or with limited motility of the coxa).
Section snippets
Insects
Insects were collected in the vicinities of Kiev (Ukraine) or Nanjing (China), sacrificed by freezing, fixed and stored in 70° ethyl alcohol without impairment of joint flexibility. Some species were donated by colleagues from their laboratory colonies or collections.
The list of investigated species is as follows:
Thermobia domestica Packard, 1837 (Zygentoma, Lepismatidae)
Aeschna affinis v. d. Linden, 1820 (Odonata, Aeschnidae)
Anax imperator Leach, 1815 (Odonata, Aeschnidae)
Nauphoeta cinerea
Body-fixed reference system
We retain the designations X, Y, Z for coordinate axes of some external reference, e.g. the field of view of a microscope. The transverse body axis q is perpendicular to the plane of symmetry, i.e. the medial plane. The choice of two other axes for the body-fixed system is arbitrary. One can construct the long axis p through any two conspicuous medial landmarks or in parallel to some straight edge (as stated in Table 2). The vertical axis v is perpendicular to q and p. Doing so, we neglect the
Size of podomers
Photographs of cursorial legs, inspected by us, are depicted in Fig. 4. The length of basal podomers (between joint midpoints), related to the total leg chain length, is shown in Table 1. Pretarsal structures were not included in the chain. We did not measure repetitive specimens and did not estimate intraspecific variability, because our task was to reveal the general tendency. The precision of our estimates lies within the order of magnitude.
The length of a podomer between joint midpoints
The universal joint
This joint belongs to the class of spherical mechanisms where all their points move along concentric spherical surfaces (Artobolevski, 1975). All axes of rotation in the spherical mechanism intersect at one common point. A ball and socket joint is the simplest spherical mechanism. A monocondylar thoracico-coxal articulation in the pleural process approaches the ball and socket joint in versatility. It has three degrees of freedom: protraction–retraction, abduction–adduction, and axial rotation.
Conclusions
Testing of the last hypothesis needs: (i) kinematic studies of the TFJ during maneuvers: walking on inclines, on rough ground, towing a load, turning, righting, etc.; (ii) evaluation of the effects of immobilization of the TFJ; (iii) measurements of angular span and force of reduction excited by electrical stimulation; (iv) recording of electrical activity in the reductor muscle during level and loaded walking. Promising objects are cockroaches, large beetles (Carabus, Geotrupes spp.,
Acknowledgements
Our thanks to colleagues who donated specimens from their collections and cultures: L. Chernyi, V. Tolkanits, T. Pushkar, A. Radchenko (Schmalhausen-Institute of Zoology, Kiev), N. Matushkina (National Shevchenko-University, Kiev), V. Richter (Zoological Institute, St Peterburg), A. Exter (Bielefeld University, Bielefeld). Two unknown reviewers greatly improved the logic of the presentation and made inevitable language corrections.
References (54)
P.W. Bateman et al.
Direct and indirect costs of limb autotomy in field crickets Gryllus bimaculatus
Animal Behaviour
(2005)
H. Cruse et al.
Movements of joint angles in the legs of a walking insect Carausius morosus
Journal of Comparative Physiology A
(1995)
L.I. Frantsevich et al.
The stick insect, Obrimus asperrimus (Phasmida, Bacillidae) walking on different substrates
Journal of Insect Physiology
(1997)
L. Frantsevich et al.
Leg coordination during turning on an extremely narrow substrate in a bug, Mesocerus marginatus (Heteroptera, Coreidae)
Journal of Insect Physiology
(2005)
K.E. Personius et al.
Control of muscle degeneration following autotomy of a hindleg in the grasshopper, Barytettix humphreysii
Journal of Insect Physiology
(2002)
S. Zill et al.
Load sensing and control of posture and locomotion
Arthropod Structure and Development
(2004)
R.McN. Alexander
Animal Mechanics
(1968)
D.W. Alsop
Comparative analysis of the intrinsic leg musculature of the American cockroach, Periplaneta americana (L
Journal of Morphology
(1978)
I.I. Artobolevski
Theory of Mechanisms and Machines
(1975)
P.W. Bateman et al.
Increased susceptibility to predation for autotomized house crickets (Acheta domestica)
Ethology
(2006)
View more references
Cited by (19)
Snow flies self-amputate freezing limbs to sustain behavior at sub-zero temperatures
2023, Current Biology
Show abstract
Anipose: A toolkit for robust markerless 3D pose estimation
2021, Cell Reports
Citation Excerpt :
Femur rotation is also likely to be important for walking in other insect species. Fransevich and Wang tested the passive rotation of the trochanter-femur articulation in 23 insect species and found rotation ranges from 10° to 120°, depending on the species (Frantsevich and Wang, 2009). Our estimate for the physiological range for walking Drosophila is about 70° (Figure 7B), which falls within the trochanter-femur articulation range observed in other insects.
Show abstract
Survey of biomechanical aspects of arthropod terrestrialisation – Substrate bound legged locomotion
2020, Arthropod Structure and Development
Citation Excerpt :
However, miniaturisation, accompanying simplification and subsequent regaining of larger body size, has probably shaped the structure of limbs and other body parts in many arthropod taxa (cp. Shultz, 1989; Frantsevich and Wang, 2009). The sequence might even have caused the probably repeated shift from muscle-antagonistically driven leg joints to semi-hydraulically driven leg joints in the arachnid class (Shultz, 1989; Sensenig and Shultz, 2003).
Show abstract
Effects of force detecting sense organs on muscle synergies are correlated with their response properties
2017, Arthropod Structure and Development
Citation Excerpt :
We examined the structure of the of trochanter-femur articulations in cockroaches and stick insects to gain insight into how forces are transmitted as strains at the joints. Most intrinsic joints in insect legs are comparable in design (hinge: coxo-trochanteral, femorotibial joints; ball and socket: tibio-tarsal joint, condylar joints: tarsal segments) but the joint between the trochanter and femur varies in structure and range of movement in different species (Frantsevich and Wang, 2009). In cockroaches, the TrF articulation is a mobile joint (Fig. 1A; Pringle, 1938; Bender et al., 2010).
Show abstract
Force feedback reinforces muscle synergies in insect legs
2015, Arthropod Structure and Development
Show abstract
A self-locking mechanism of the frog-legged beetle Sagra femorata
2024, Insect Science
View all citing articles on Scopus
View full text
Copyright © 2008 Elsevier Ltd. All rights reserved.
Recommended articles
Numerical simulation of colloidal self-assembly of super-hydrophobic arachnid cerotegument structures
Journal of Theoretical Biology, Volume 430, 2017, pp. 1-8
Alexander É. Filippov, …, Stanislav N. Gorb
Variations and adaptations of associated liver partition and portal vein ligation for staged hepatectomy (ALPPS): Many routes to the summit
Surgery, Volume 159, Issue 4, 2016, pp. 1058-1072
Matthew J. Edmondson, …, Long R. Jiao
Thermal development of the endoparasitoid Aphelinus maculatus Yasnosh (Hymenoptera: Aphelinidae) parasitizing Myzus persicae Sulzer (Homoptera: Aphididae)
Journal of Thermal Biology, Volume 101, 2021, Article 103097
Ke-Zhuo Li, …, Li-Qing Duan
Show 3 more articles
Article Metrics
Citations
Citation Indexes:
19
Captures
Readers:
37
Mentions
References:
2
plumX logoView details
Elsevier logo with wordmark
About ScienceDirect
Remote access
Shopping cart
Advertise
Contact and support
Terms and conditions
Privacy policy
Cookies are used by this site. Cookie settings | Your Privacy Choices
All content on this site: Copyright © 2024 Elsevier B.V., its licensors, and contributors. All rights are reserved, including those for text and data mining, AI training, and similar technologies. For all open access content, the Creative Commons licensing terms apply.
RELX group home page
Feedback | biology | 2049602 | https://no.wikipedia.org/wiki/Acalyptini | Acalyptini | Acalyptini er en gruppe av små biller med lang, tynn snute. Billene lever på levende planter.
Utseende
Små til middelsstore (ofte 2 – 6 mm) biller av sterkt varierende kroppsform. Felles for alle er at hodet er trukket ut til en lang og tynn snute (i ekstreme tilfeller lengre enn resten av kroppen), og at antennene er knebøyde (unntatt hos slekten Rhamphus). Oversiden er mer eller mindre skjellkledt og matt. Kroppsformen varierer mellom kort oval (slekten Curculio) og ganske langstrakt (for eksempel slektene Dorytomus og Brachonyx), vanligvis høyt hvelvet, men flat og bred hos gruppen hoppsnutebiller (Rhamphini). Hodet er forholdsvis lite. Den lange snuten kan ikke legges inn i en fure mellom framhoftene og holdes ofte framoverrettet. Brystskjoldet er bredere enn langt, bakerst ofte omtrent så bredt som dekkvingene ved roten. Beina er vanligvis forholdsvis lange og kraftige, noen ganger (bl.a. noen arter i slekten Dorytomus) er frambeina sterkt forlenget. Hos gruppen hoppsnutebiller er bakbeina utviklet til hoppebein, men sterkt fortykkede lår. Lårene har ofte kraftige tenner på undersiden (for eksempel hos slekten Anthonomus).
Levevis
Denne underfamilien går på levende planter, og larvene utvikler seg som oftest i blomster, frukter eller frø.
Systematisk inndeling / norske arter
Gruppen kan også plasseres som en undergruppe av Derelomini.
Ordenen biller, Coleoptera Linnaeus, 1758
Underordenen Polyphaga Emery, 1886
Gruppen (infraorden) Cucujiformia Lameere, 1938
Overfamilien Snutebiller, Curculionoidea Latreille, 1802
Familien Snutebiller, Curculionidae Latreille, 1802
Underfamilien Snutebiller, Curculioninae Latreille, 1802
Stammen AcalyptiniThomson, 1859
Slekten Acalyptus Schönherr, 1833 - 10 arter, i Norge:
Acalyptus carpini (Fabricius, 1792)
Slekten Amorphoidea Motschulsky, 1858 - 20 arter
Slekten Anchylorhynchus Schönherr, 1833 - 25 arter
Slekten Azotoctla Cardona-Duque, 2011 - 15 arter, neotropisk
Slekten Derelomus Schönherr, 1825 - 6 arter
Slekten Parimera Faust, 1896 - 14 arter
Slekten Sphincticraeropsis Voss, 1944 - 3 arter
Referanser
Kilder
Milne, L. og Milne, M. 1980. The Audubon Society Field Guide to North American Insects and Spiders. Alfred A. Knopf, New York. Om bomullssnutebillen, s. 613.
Silfverberg, H. 1992. Enumeratio Coleopterorum Fennoscandiae, Daniae et Baltiae (Liste over Nordens biller). Helsinki.
Zahradník, J. og Chvála, M. 1991. Teknologisk forlags store bok om insekter. N.W. Damm. Om snutebiller, s. 381-395.
Eksterne lenker
Snutebiller
Biller formelt beskrevet i 1859 | norwegian_bokmål | 0.814419 |
insescts_six_legs/Walking.txt | Walking (also known as ambulation) is one of the main gaits of terrestrial locomotion among legged animals. Walking is typically slower than running and other gaits. Walking is defined by an "inverted pendulum" gait in which the body vaults over the stiff limb or limbs with each step. This applies regardless of the usable number of limbs—even arthropods, with six, eight, or more limbs, walk. In humans, walking has health benefits including improved mental health and reduced risk of cardiovascular disease and death.
Difference from running[edit]
Main article: Running
See also: Jogging
Racewalkers at the World Cup Trials in 1987
The word walk is descended from the Old English wealcan 'to roll'. In humans and other bipeds, walking is generally distinguished from running in that only one foot at a time leaves contact with the ground and there is a period of double-support. In contrast, running begins when both feet are off the ground with each step. This distinction has the status of a formal requirement in competitive walking events. For quadrupedal species, there are numerous gaits which may be termed walking or running, and distinctions based upon the presence or absence of a suspended phase or the number of feet in contact any time do not yield mechanically correct classification. The most effective method to distinguish walking from running is to measure the height of a person's centre of mass using motion capture or a force plate at mid-stance. During walking, the centre of mass reaches a maximum height at mid-stance, while running, it is then at a minimum. This distinction, however, only holds true for locomotion over level or approximately level ground. For walking up grades above 10%, this distinction no longer holds for some individuals. Definitions based on the percentage of the stride during which a foot is in contact with the ground (averaged across all feet) of greater than 50% contact corresponds well with identification of 'inverted pendulum' mechanics and are indicative of walking for animals with any number of limbs, however this definition is incomplete. Running humans and animals may have contact periods greater than 50% of a gait cycle when rounding corners, running uphill or carrying loads.
Speed is another factor that distinguishes walking from running. Although walking speeds can vary greatly depending on many factors such as height, weight, age, terrain, surface, load, culture, effort, and fitness, the average human walking speed at crosswalks is about 5.0 kilometres per hour (km/h), or about 1.4 meters per second (m/s), or about 3.1 miles per hour (mph). Specific studies have found pedestrian walking speeds at crosswalks ranging from 4.51 to 4.75 km/h (2.80 to 2.95 mph) for older individuals and from 5.32 to 5.43 km/h (3.31 to 3.37 mph) for younger individuals; a brisk walking speed can be around 6.5 km/h (4.0 mph). In Japan, the standard measure for walking speed is 80 m/min (4.8 km/h).
Champion racewalkers can average more than 14 km/h (8.7 mph) over a distance of 20 km (12 mi).
An average human child achieves independent walking ability at around 11 months old.
Health benefits[edit]
Main article: Physical exercise
Regular, brisk exercise can improve confidence, stamina, energy, weight control and may reduce stress. Scientific studies have also shown that walking may be beneficial for the mind, improving memory skills, learning ability, concentration, mood, creativity, and abstract reasoning. Sustained walking sessions for a minimum period of thirty to sixty minutes a day, five days a week, with the correct walking posture may improve health.
The Centers for Disease Control and Prevention's fact sheet on the "Relationship of Walking to Mortality Among U.S. Adults with Diabetes" states that those with diabetes who walked for two or more hours a week lowered their mortality rate from all causes by 39 percent. Women who took 4,500 steps to 7,500 steps a day seemed to have fewer premature deaths compared to those who only took 2,700 steps a day. "Walking lengthened the life of people with diabetes regardless of age, sex, race, body mass index, length of time since diagnosis and presence of complications or functional limitations." One limited study found preliminary evidence of a relationship between the speed of walking and health, and that the best results are obtained with a speed of more than 2.5 mph (4.0 km/h).
A 2023 study by the European Journal of Preventive Cardiology, the largest study to date, found that walking at least 2,337 steps a day reduced the risk of dying from cardiovascular diseases, and that 3,967 steps a day reduced the risk of dying from any cause. Benefits continued to increase with more steps. James Leiper, associate medical director at the British Heart Foundation, said that if the benefits of walking could be sold as a medicine "we would be hailing it as a wonder drug".
Origins[edit]
A walking hamster
It is theorized that "walking" among tetrapods originated underwater with air-breathing fish that could "walk" underwater, giving rise (potentially with vertebrates like Tiktaalik) to the plethora of land-dwelling life that walk on four or two limbs. While terrestrial tetrapods are theorised to have a single origin, arthropods and their relatives are thought to have independently evolved walking several times, specifically in insects, myriapods, chelicerates, tardigrades, onychophorans, and crustaceans. Little skates, members of the demersal fish community, can propel themselves by pushing off the ocean floor with their pelvic fins, using neural mechanisms which evolved as early as 420 million years ago, before vertebrates set foot on land.
Hominin[edit]
Data in the fossil record indicate that among hominin ancestors, bipedal walking was one of the first defining characteristics to emerge, predating other defining characteristics of Hominidae. Judging from footprints discovered on a former shore in Kenya, it is thought possible that ancestors of modern humans were walking in ways very similar to the present activity as long as 3 million years ago.
Today, the walking gait of humans is unique and differs significantly from bipedal or quadrupedal walking gaits of other primates, like chimpanzees. It is believed to have been selectively advantageous in hominin ancestors in the Miocene due to metabolic energy efficiency. Human walking has been found to be slightly more energy efficient than travel for a quadrupedal mammal of a similar size, like chimpanzees. The energy efficiency of human locomotion can be accounted for by the reduced use of muscle in walking, due to an upright posture which places ground reaction forces at the hip and knee. When walking bipedally, chimpanzees take a crouched stance with bent knees and hips, forcing the quadriceps muscles to perform extra work, which costs more energy. Comparing chimpanzee quadrupedal travel to that of true quadrupedal animals has indicated that chimpanzees expend one-hundred and fifty percent of the energy required for travel compared to true quadrupeds.
In 2007, a study further explored the origin of human bipedalism, using chimpanzee and human energetic costs of locomotion. They found that the energy spent in moving the human body is less than what would be expected for an animal of similar size and approximately seventy-five percent less costly than that of chimpanzees. Chimpanzee quadrupedal and bipedal energy costs are found to be relatively equal, with chimpanzee bipedalism costing roughly ten percent more than quadrupedal. The same 2007 study found that among chimpanzee individuals, the energy costs for bipedal and quadrupedal walking varied significantly, and those that flexed their knees and hips to a greater degree and took a more upright posture, closer to that of humans, were able to save more energy than chimpanzees that did not take this stance. Further, compared to other apes, humans have longer legs and short dorsally oriented ischia (hipbone), which result in longer hamstring extensor moments, improving walking energy economy. Longer legs also support lengthened Achilles tendons which are thought to increase energy efficiency in bipedal locomotor activities. It was thought that hominins like Ardipithecus ramidus, which had a variety of both terrestrial and arboreal adaptions would not be as efficient walkers, however, with a small body mass A. ramidus had developed an energy efficient means of bipedal walking while still maintaining arboreal adaptations. Humans have long femoral necks, meaning that while walking, hip muscles do not require as much energy to flex while moving. These slight kinematic and anatomic differences demonstrate how bipedal walking may have developed as the dominant means of locomotion among early hominins because of the energy saved.
Variants[edit]
Nordic walkers
Scrambling is a method of ascending a hill or mountain that involves using both hands, because of the steepness of the terrain. Of necessity, it will be a slow and careful form of walking and with possibly of occasional brief, easy rock climbing. Some scrambling takes place on narrow exposed ridges where more attention to balance will be required than in normal walking.
Snow shoeing – Snowshoes are footwear for walking over the snow. Snowshoes work by distributing the weight of the person over a larger area so that the person's foot does not sink completely into the snow, a quality called "flotation". It is often said by snowshoers that if you can walk, you can snowshoe. This is true in optimal conditions, but snowshoeing properly requires some slight adjustments to walking. The method of walking is to lift the shoes slightly and slide the inner edges over each other, thus avoiding the unnatural and fatiguing "straddle-gait" that would otherwise be necessary. A snowshoer must be willing to roll his or her feet slightly as well. An exaggerated stride works best when starting out, particularly with larger or traditional shoes.
Cross-country skiing – originally conceived like snow shoes as a means of travel in deep snow. Trails hiked in the summer are often skied in the winter and the Norwegian Trekking Association maintains over 400 huts stretching across thousands of kilometres of trails which hikers can use in the summer and skiers in the winter.
Beach walking is a sport that is based on a walk on the sand of the beach. Beach walking can be developed on compact sand or non-compact sand. There are beach walking competitions on non-compact sand, and there are world records of beach walking on non-compact sand in Multiday distances. Beach walking has a specific technique of walk.
Free heels are a defining characteristic of ski touring
Nordic walking is a physical activity and a sport, which is performed with specially designed walking poles similar to ski poles. Compared to regular walking, Nordic walking (also called pole walking) involves applying force to the poles with each stride. Nordic walkers use more of their entire body (with greater intensity) and receive fitness building stimulation not present in normal walking for the chest, lats, triceps, biceps, shoulder, abdominals, spinal and other core muscles that may result in significant increases in heart rate at a given pace. Nordic walking has been estimated as producing up to a 46% increase in energy consumption, compared to walking without poles.
Pedestrianism is a sport that developed during the late eighteenth and nineteenth centuries, and was a popular spectator sport in the British Isles. By the end of the 18th century, and especially with the growth of the popular press, feats of foot travel over great distances (similar to a modern ultramarathon) gained attention, and were labeled "pedestrianism". Interest in the sport, and the wagering which accompanied it, spread to the United States, Canada, and Australia in the 19th century. By the end of the 19th century, Pedestrianism was largely displaced by the rise in modern spectator sports and by controversy involving rules, which limited its appeal as a source of wagering and led to its inclusion in the amateur athletics movement. Pedestrianism was first codified in the last half of the 19th century, evolving into what would become racewalking, By the mid 19th century, competitors were often expected to extend their legs straight at least once in their stride, and obey what was called the "fair heel and toe" rule. This rule, the source of modern racewalking, was a vague commandment that the toe of one foot could not leave the ground before the heel of the next foot touched down. This said, rules were customary and changed with the competition. Racers were usually allowed to jog in order to fend off cramps, and it was distance, not code, which determined gait for longer races. Newspaper reports suggest that "trotting" was common in events.
Speed walking is the general term for fast walking. Within the Speed Walking category are a variety of fast walking techniques: Power Walking, Fit Walking, etc.
Power walking is the act of walking with a speed at the upper end of the natural range for walking gait, typically 7 to 9 km/h (4.3 to 5.6 mph). To qualify as power walking as opposed to jogging or running, at least one foot must be in contact with the ground at all times.
Racewalking is a long-distance athletic event. Although it is a foot race, it is different from running in that one foot must appear to be in contact with the ground at all times. Stride length is reduced, so to achieve competitive speeds, racewalkers must attain cadence rates comparable to those achieved by Olympic 800-meter runners, and they must do so for hours at a time since the Olympic events are the 20 km (12 mi) race walk (men and women) and 50 km (31 mi) race walk (men only), and 50-mile (80 km) events are also held. See also pedestrianism above.
Afghan walking: The Afghan Walk is a rhythmic breathing technique synchronized with walking. It was born in the 1980s on the basis of the observations made by the Frenchman Édouard G. Stiegler, during his contacts with Afghan caravaners, capable of making walks of more than 60 km per day for dozens of days.
Backward walking: In this activity, an individual walks in reverse, facing away from their intended direction of movement. This unique form of exercise has gained popularity for its various health and fitness benefits. It requires more attention and engages different muscles than forward walking, making it a valuable addition to a fitness routine. Some potential benefits of retro walking include improved balance, enhanced coordination, strengthened leg muscles, and reduced knee stress. It is also a rehabilitation exercise for certain injuries and can be way to switch up one's workout routine.
Biomechanics[edit]
Human walking cycle
Human walking is accomplished with a strategy called the double pendulum. During forward motion, the leg that leaves the ground swings forward from the hip. This sweep is the first pendulum. Then the leg strikes the ground with the heel and rolls through to the toe in a motion described as an inverted pendulum. The motion of the two legs is coordinated so that one foot or the other is always in contact with the ground. While walking, the muscles of the calf contract, raising the body's center of mass, while this muscle is contracted, potential energy is stored. Then gravity pulls the body forward and down onto the other leg and the potential energy is then transformed into kinetic energy. The process of human walking can save approximately sixty-five percent of the energy used by utilizing gravity in forward motion.
Walking differs from a running gait in a number of ways. The most obvious is that during walking one leg always stays on the ground while the other is swinging. In running there is typically a ballistic phase where the runner is airborne with both feet in the air (for bipedals).
Another difference concerns the movement of the centre of mass of the body. In walking the body "vaults" over the leg on the ground, raising the centre of mass to its highest point as the leg passes the vertical, and dropping it to the lowest as the legs are spread apart. Essentially kinetic energy of forward motion is constantly being traded for a rise in potential energy. This is reversed in running where the centre of mass is at its lowest as the leg is vertical. This is because the impact of landing from the ballistic phase is absorbed by bending the leg and consequently storing energy in muscles and tendons. In running there is a conversion between kinetic, potential, and elastic energy.
There is an absolute limit on an individual's speed of walking (without special techniques such as those employed in speed walking) due to the upwards acceleration of the centre of mass during a stride – if it is greater than the acceleration due to gravity the person will become airborne as they vault over the leg on the ground. Typically, however, animals switch to a run at a lower speed than this due to energy efficiencies.
Based on the 2D inverted pendulum model of walking, there are at least five physical constraints that place fundamental limits on walking like an inverted pendulum. These constraints are: take-off constraint, sliding constraint, fall-back constraint, steady-state constraint, high step-frequency constraint.
Leisure activity[edit]
Main articles: Hiking and Walking tour
Hiking with full packs
Many people enjoy walking as a recreation in the mainly urban modern world, and it is one of the best forms of exercise. For some, walking is a way to enjoy nature and the outdoors; and for others the physical, sporting and endurance aspect is more important.
There are a variety of different kinds of walking, including bushwalking, racewalking, beach walking, hillwalking, volksmarching, Nordic walking, trekking, dog walking and hiking. Some people prefer to walk indoors on a treadmill, or in a gym, and fitness walkers and others may use a pedometer to count their steps. Hiking is the usual word used in Canada, the United States and South Africa for long vigorous walks; similar walks are called tramps in New Zealand, or hill walking or just walking in Australia, the UK and the Irish Republic. In the UK, rambling is also used. Australians also bushwalk. In English-speaking parts of North America, the term walking is used for short walks, especially in towns and cities. Snow shoeing is walking in snow; a slightly different gait is required compared with regular walking.
Tourism[edit]
In terms of tourism, the possibilities range from guided walking tours in cities, to organized trekking holidays in the Himalayas. In the UK the term walking tour also refers to a multi-day walk or hike undertaken by a group or individual. Well-organized systems of trails exist in many other European counties, as well as Canada, United States, New Zealand, and Nepal. Systems of lengthy waymarked walking trails now stretch across Europe from Norway to Turkey, Portugal to Cyprus. Many also walk the traditional pilgrim routes, of which the most famous is El Camino de Santiago, The Way of St. James.
Numerous walking festivals and other walking events take place each year in many countries. The world's largest multi-day walking event is the International Four Days Marches Nijmegen in the Netherlands. The "Vierdaagse" (Dutch for "Four day Event") is an annual walk that has taken place since 1909; it has been based at Nijmegen since 1916. Depending on age group and category, walkers have to walk 30, 40 or 50 kilometers each day for four days. Originally a military event with a few civilians, it now is a mainly civilian event. Numbers have risen in recent years, with over 40,000 now taking part, including about 5,000 military personnel. Due to crowds on the route, since 2004 the organizers have limited the number of participants. In the U.S., there is the annual Labor Day walk on Mackinac Bridge, Michigan, which draws over 60,000 participants; it is the largest single-day walking event; while the Chesapeake Bay Bridge Walk in Maryland draws over 50,000 participants each year. There are also various walks organised as charity events, with walkers sponsored for a specific cause. These walks range in length from two miles (3 km) or five km to 50 miles (80 km). The MS Challenge Walk is an 80 km or 50-mile walk which raises money to fight multiple sclerosis, while walkers in the Oxfam Trailwalker cover 100 km or 60 miles.
Rambling[edit]
In Britain, The Ramblers, a registered charity, is the largest organisation that looks after the interests of walkers, with some 100,000 members. Its "Get Walking Keep Walking" project provides free route guides, led walks, as well as information for people new to walking. The Long Distance Walkers Association in the UK is for the more energetic walker, and organizes lengthy challenge hikes of 20 or even 50 miles (30 to 80 km) or more in a day. The LDWA's annual "Hundred" event, entailing walking 100 miles or 160 km in 48 hours, takes place each British Spring Bank Holiday weekend.
Walkability[edit]
Main article: Walkability
Gauchetière Street, Montreal, Quebec, Canada
There has been a recent focus among urban planners in some communities to create pedestrian-friendly areas and roads, allowing commuting, shopping and recreation to be done on foot. The concept of walkability has arisen as a measure of the degree to which an area is friendly to walking. Some communities are at least partially car-free, making them particularly supportive of walking and other modes of transportation. In the United States, the active living network is an example of a concerted effort to develop communities more friendly to walking and other physical activities.
An example of such efforts to make urban development more pedestrian friendly is the pedestrian village. This is a compact, pedestrian-oriented neighborhood or town, with a mixed-use village center, that follows the tenets of New Pedestrianism. Shared-use lanes for pedestrians and those using bicycles, Segways, wheelchairs, and other small rolling conveyances that do not use internal combustion engines. Generally, these lanes are in front of the houses and businesses, and streets for motor vehicles are always at the rear. Some pedestrian villages might be nearly car-free with cars either hidden below the buildings or on the periphery of the village. Venice, Italy is essentially a pedestrian village with canals. The canal district in Venice, California, on the other hand, combines the front lane/rear street approach with canals and walkways, or just walkways.
Walking is also considered to be a clear example of a sustainable mode of transport, especially suited for urban use and/or relatively shorter distances. Non-motorized transport modes such as walking, but also cycling, small-wheeled transport (skates, skateboards, push scooters and hand carts) or wheelchair travel are often key elements of successfully encouraging clean urban transport. A large variety of case studies and good practices (from European cities and some worldwide examples) that promote and stimulate walking as a means of transportation in cities can be found at Eltis, Europe's portal for local transport.
The development of specific rights of way with appropriate infrastructure can promote increased participation and enjoyment of walking. Examples of types of investment include pedestrian malls, and foreshoreways such as oceanways and also river walks.
The first purpose-built pedestrian street in Europe is the Lijnbaan in Rotterdam, opened in 1953. The first pedestrianised shopping centre in the United Kingdom was in Stevenage in 1959. A large number of European towns and cities have made part of their centres car-free since the early 1960s. These are often accompanied by car parks on the edge of the pedestrianised zone, and, in the larger cases, park and ride schemes. Central Copenhagen is one of the largest and oldest: It was converted from car traffic into pedestrian zone in 1962.
In robotics[edit]
Main article: Robot locomotion
This section has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. (September 2009) (Learn how and when to remove this template message)
This section needs to be updated. Please help update this article to reflect recent events or newly available information. Last update: 2009 (July 2018)
(Learn how and when to remove this template message)
Generally, the first successful walking robots had six legs. As microprocessor technology advanced, the number of legs could be reduced and there are now robots that can walk on two legs. One, for example, is ASIMO. Although there has been significant advances, robots still do not walk nearly as well as human beings as they often need to keep their knees bent permanently in order to improve stability.
In 2009, Japanese roboticist Tomotaka Takahashi developed a robot that can jump three inches off the ground. The robot, named Ropid, is capable of getting up, walking, running, and jumping.
Many other robots have also been able to walk over the years like a bipedal walking robot.
Mathematical models[edit]
Multiple mathematical models have been proposed to reproduce the kinematics observed in walking. These may be broadly broken down into four categories: rule-based models based on mechanical considerations and past literature, weakly coupled phase oscillators models, control-based models which guide simulations to maximize some property of locomotion, and phenomenological models which fit equations directly to the kinematics.
Rule-based models[edit]
The rule-based models integrate the past literature on motor control to generate a few simple rules which are presumed to be responsible for walking (e.g. “loading of the left leg triggers unloading of right leg”). Such models are generally most strictly based on the past literature and when they are based on a few rules can be easy to interpret. However, the influence of each rule can be hard to interpret when these models become more complex. Furthermore, the tuning of parameters is often done in an ad hoc way, revealing little intuition about why the system may be organized in this way. Finally, such models are typically based fully on sensory feedback, ignoring the effect of descending and rhythm generating neurons, which have been shown to be crucial in coordinating proper walking.
Coupled oscillator models[edit]
Dynamical system theory shows that any network with cyclical dynamics may be modeled as a set of weakly coupled phase oscillators, so another line of research has been exploring this view of walking. Each oscillator may model a muscle, joint angle, or even a whole leg, and is coupled to some set of other oscillators. Often, these oscillators are thought to represent the central pattern generators underlying walking. These models have rich theory behind them, allow for some extensions based on sensory feedback, and can be fit to kinematics. However, they need to be heavily constrained to fit to data and by themselves make no claims on which gaits allow the animal to move faster, more robustly, or more efficiently.
Control based models[edit]
Control-based models start with a simulation based on some description of the animal's anatomy and optimize control parameters to generate some behavior. These may be based on a musculoskeletal model, skeletal model, or even simply a ball and stick model. As these models generate locomotion by optimizing some metric, they can be used to explore the space of optimal locomotion behaviors under some assumptions. However, they typically do not generate plausible hypotheses on the neural coding underlying the behaviors and are typically sensitive to modeling assumptions.
Statistical models[edit]
Phenomenological models model the kinematics of walking directly by fitting a dynamical system, without postulating an underlying mechanism for how the kinematics are generated neurally. Such models can produce the most realistic kinematic trajectories and thus have been explored for simulating walking for computer-based animation. However, the lack of underlying mechanism makes it hard to apply these models to study the biomechanical or neural properties of walking.
Animals[edit]
Main article: Terrestrial locomotion
See also: Gait
Horses[edit]
Main article: Horse gait
The walk, a four-beat gait
The walk is a four-beat gait that averages about 4 miles per hour (6.4 km/h). When walking, a horse's legs follow this sequence: left hind leg, left front leg, right hind leg, right front leg, in a regular 1-2-3-4 beat. At the walk, the horse will always have one foot raised and the other three feet on the ground, save for a brief moment when weight is being transferred from one foot to another. A horse moves its head and neck in a slight up and down motion that helps maintain balance.
Ideally, the advancing rear hoof oversteps the spot where the previously advancing front hoof touched the ground. The more the rear hoof oversteps, the smoother and more comfortable the walk becomes. Individual horses and different breeds vary in the smoothness of their walk. However, a rider will almost always feel some degree of gentle side-to-side motion in the horse's hips as each hind leg reaches forward.
The fastest "walks" with a four-beat footfall pattern are actually the lateral forms of ambling gaits such as the running walk, singlefoot, and similar rapid but smooth intermediate speed gaits. If a horse begins to speed up and lose a regular four-beat cadence to its gait, the horse is no longer walking but is beginning to either trot or pace.
Elephants[edit]
An Asian elephant walking
Elephants can move both forwards and backwards, but cannot trot, jump, or gallop. They use only two gaits when moving on land, the walk and a faster gait similar to running. In walking, the legs act as pendulums, with the hips and shoulders rising and falling while the foot is planted on the ground. With no "aerial phase", the fast gait does not meet all the criteria of running, although the elephant uses its legs much like other running animals, with the hips and shoulders falling and then rising while the feet are on the ground. Fast-moving elephants appear to 'run' with their front legs, but 'walk' with their hind legs and can reach a top speed of 18 km/h (11 mph). At this speed, most other quadrupeds are well into a gallop, even accounting for leg length.
Walking fish[edit]
Main article: Walking fish
A mudskipper, a type of walking fish, perched on land
Walking fish (or ambulatory fish) are fish that are able to travel over land for extended periods of time. The term may also be used for some other cases of nonstandard fish locomotion, e.g., when describing fish "walking" along the sea floor, as the handfish or frogfish.
Insects[edit]
Insects must carefully coordinate their six legs during walking to produce gaits that allow for efficient navigation of their environment. Interleg coordination patterns have been studied in a variety of insects, including locusts (Schistocerca gregaria), cockroaches (Periplaneta americana), stick insects (Carausius morosus), and fruit flies (Drosophila melanogaster). Different walking gaits have been observed to exist on a speed dependent continuum of phase relationships. Even though their walking gaits are not discrete, they can often be broadly categorized as either a metachronal wave gait, tetrapod gait, or tripod gait.
In a metachronal wave gait, only one leg leaves contact with the ground at a time. This gait starts at one of the hind legs, then propagates forward to the mid and front legs on the same side before starting at the hind leg of the contralateral side. The wave gait is often used at slow walking speeds and is the most stable, since five legs are always in contact with the ground at a time.
In a tetrapod gait, two legs swing at a time while the other four legs remain in contact with the ground. There are multiple configurations for tetrapod gaits, but the legs that swing together must be on contralateral sides of the body. Tetrapod gaits are typically used at medium speeds and are also very stable.
A walking gait is considered tripod if three of the legs enter the swing phase simultaneously, while the other three legs make contact with the ground. The middle leg of one side swings with the hind and front legs on the contralateral side. Tripod gaits are most commonly used at high speeds, though it can be used at lower speeds. The tripod gait is less stable than wave-like and tetrapod gaits, but it is theorized to be the most robust. This means that it is easier for an insect to recover from an offset in step timing when walking in a tripod gait. The ability to respond robustly is important for insects when traversing uneven terrain.
See also[edit]
Sport of athletics portal
Arm swing in human locomotion
Duckwalk
Footpath
Gait training
Hand walking
International charter for walking
Kinhin
List of longest walks
Obesity and walking
Preferred walking speed
Student transport
Tobler's hiking function
Walkathon
Walking audit
Walking bus
Walking tour | biology | 218282 | https://sv.wikipedia.org/wiki/Ringsvanslemur | Ringsvanslemur | Ringsvanslemur eller kattmaki (Lemur catta) är en art i familjen lemurer, inom ordningen primater. Ringsvanslemuren räknas idag som den enda arten i släktet Lemur.
Utseende
Djuret utmärks av ett långsträckt huvud, som liknar rävens, med ganska stora ögon och öron. Öronen har tät hårväxt, ofta till och med hårknippen. Bakbenen är betydligt längre än frambenen. Vristen är inte förlängd. Händerna och fötterna är tunnhåriga på ovansidan. Svansen är längre än kroppen och pälsen är mjuk, undantagsvis också ullig.
En ringsvanslemur blir ungefär 39 till 46 centimeter lång, med 56 till 62 centimeter lång svans. Vikten varierar mellan 2,2 och 3,5 kilogram. Hos arten finns ingen utpräglad könsdimorfism, könen har samma färgsättning och är ungefär lika stora. Färgen växlar från grå till roströd. Nosen och en ring omkring ögat är svarta. Ansiktet, öronen och kroppens undre sida är vita och svansen har 13 till 15 svarta och vita ringar. Händernas och fötternas undersida är långsträckt och täckt med läderartad hud och är lämplig för klättring i klippiga områden. Den första tån är i jämförelse till samma tå hos besläktade arter som lever i träd förminskade. Fingrarna och tårna på bakfoten bär naglar. Bara den andra tån bär liksom hos alla andra djur i underordningen Strepsirhini en klo för att vårda pälsen.
Ögonen har en ljusbrun till orange färg och ett skikt som reflekterar ljus (Tapetum lucidum). Kring varje öga finns mörkbruna till svarta fläckar som ungefär har en trekantig form.
Tandformeln är I2 C1 P3 M3, alltså 36 tänder sammanräknade. Överkäkens framtänder är små och alla lika stora. Mellan de övre hörntänder och kindtänder finns en mindre klaff.
Hos bägge kön förekommer doftkörtlar vid handleden. Hos hanar saknar stället hår. Denna fläck har en diameter upp till två centimeter och är utrustade med en tagg av hornämne. Honornas fläck är mindre. De flesta hanar har dessutom en körtel på bröstet precis ovanpå nyckelbenet, hos honor är denna körtel förminskade eller saknas helt. Bägge kön har däremot körtlar vid anusöppningen. Honornas två spenar ligger på brösten.
Utbredning och habitat
Denna art lever socialt i grupper i skogarna på Madagaskar och angränsande öar. Utbredningsområdet ligger i ön södra och sydvästra delar. I väst ligger gränsen något norr om floden Mangoky, i sydöst förekommer arten fram till staden Taolanaro. Isolerade populationer i öns inre förekommer upp till 2 600 meter över havet. Under de senaste 50 åren ändrades utbredningsområdet inte påfallande. Regionen kan till och med vara större än hittills känd.
Ringsvanslemuren är den art i delordningen Lemuriformes med största variation av habitatet. Den föredrar skogar med törnförsedda växter, torra lövskogar, galleriskog samt savanner med några buskar. I bergstrakter förekommer arten i klippiga regioner ovanpå trädgränsen. Arten uthärdar alltså mycket olika klimatförhållanden. Den lever i torra regioner i Madagaskars sydvästra del som bara har 30 till 50 millimeter nederbörd per år, men även i bergsområden där temperaturen varierar mellan -7 och +24° Celsius.
Levnadssätt
Aktivitet och rörelser
Till skillnad från många andra primater i underordningen Strepsirrhini är de dagaktiva (och alltså inte nattdjur). På natten uppsöker de träd för att sova. Individer i bergsområden vilar i grottor ofta tätt bredvid varandra för att värma sig. Mellan klockan 5:30 och 8:30 på morgonen blir de aktiva, vanligen genom att solbada, särskilt när det är kyligt. Vid denna sysselsättning intar de en typisk ställning med upprätt överkropp, särade ben och händerna vilande på låren, så att undersidan får tillräckligt solljus. Sedan följer en aktiv tid där de letar efter föda eller rör sig på grund av andra skäl. Ungefär vid dagens mitt håller de rast. Vid kraftig hetta vilar de upp till fyra timmar. På eftermiddagen följer den andra aktiva fasen. Mellan cirka klockan 18:30 och 19:30 uppsöker ringsvanslemurer sina sovplatser. Ibland är de även aktiva på natten för att äta eller vårda pälsen men de sitter kvar på samma träd.
Arten vistas cirka 30 procent av sin tid på marken, något som är rekord hos dagens lemurer. Bara för utdöda medlemmar som det jättestora släktet Archaeoindris antas att de helt levde på marken. På marken går djuret på fyra fötter och håller svansen i luften. Svansens spets är där böjd bakåt och hela svansen påminner om ett frågetecken. Även på träd klättrar de med fyra extremiteter men de kan hoppa över större avstånd. Svansen används på träd för att hålla balansen.
De klättrar snabbt och vigt, gör långa språng från gren till gren, där de söker efter de insekter och frukter samt några andra växtdelar som de lever av.
Socialt beteende och revir
Ringsvanslemurer lever i grupper med genomsnittligt 13 till 15 individer, antalet djur i gruppen kan variera mellan 6 och något över 30. Flocken är sammansatt av ungefär lika många hanar, honor och ungar. Grupperna domineras av honorna. Då individer av honkön nästan alltid stannar i gruppen där de föddes bildas flockens kärna av en familj med nära besläktade honor. Ledningen övertas av en alfahona som bestämmer riktningen för gruppens vandringar och andra interaktioner. De övriga honorna etablerar en hierarki. Positionen i hierarkin ärvs inte och döttrar får ingen hjälp av sina mödrar för att få en bättre plats i rangordningen. I större grupper förekommer ibland flera familjer. Individer av samma familj vistas där närmare bredvid varandra och känns igen när de vårdar varandras päls. Mellan honor som inte är släkt uppstår oftare aggressioner.
Vuxna honor visar sin dominans även mot hanar, de jagar bort hanarna eller slår och biter dem. Hanarna måste lämna sin grupp när de blir könsmogna. Har hannarna hittat en ny grupp upprättar de likaså en hierarki. Därför utför de så kallade ”stänkstrider” . De flyttar sekret från körteln på armen till svansen och viftar med svansen framför motståndarens huvud. För det mesta finns tre hanar med hög ställning i gruppen och flera hanar med lägre ställning. Hanarnas position är även beroende på individens ålder. Dominerande hanar är vanligen mellan 6 och 9 år gamla. Underordnade hanar är antingen yngre eller äldre, eller de är nya i flocken. Dominerande hanar vistas oftast i gruppens centrum. De är på så sätt bättre skyddade mot fiender, har bättre tillgång till föda och är närmare honorna, något som är viktigt under parningstiden.
Unga hanar lämnar vanligen sin ursprungsgrupp när de är mellan tre och fem år gamla. Ofta flyttar två eller tre hanar samtidigt och de försöker gemensamt få plats i en annan grupp. Först efter flera månader betraktas de som riktiga medlemmar av den nya gruppen. I genomsnitt byter unga hanar sin grupp med 1,4 års mellanrum. För äldre hanar ligger samma värde på 3,5 år. Bytet av flocken sker bara mellan december och maj, oftast under parningstiden i april.
När gruppen blir för stor delas den i två grupper. Uppdelningen äger rum när antalet individer ligger vid 15 till 25 eller när honornas antal ligger vid 8 till 10. Vid dessa tillfällen driver de dominanta honorna bort alla andra honor. De senare upprättar efteråt en egen flock, sällan får de ansluta till en annan grupp. Nya grupper har ofta ett fåtal medlemmar och de har svårt att komma fram till platser med föda.
Ringsvanslemurer har inga helt avgränsade revir men föredrar vissa vandringsleder. Beroende på region och årstid vandrar de genom territorier som är 6 till 30 hektar stora. I våta regioner och under regntiden är territoriet mindre medan det i torra regioner eller under den torra årstiden är större. Flocken vandrar per dag ungefär 1 000 meter och använder samma avsnitt av leden tre till fyra dagar. Sedan flyttar de till en annan plats.
Vandringsleden markeras med sekret av körtlarna. Honor använder därför körteln vid anus och hanar skrapar med det taggiga utskottet vid handleden på mindre trädstammar eller grenar och lämnar på så sätt sitt doftspår. Vandringsleder av olika grupper kan överlappas. När två flockar träffas försvaras gruppen vanligen av honorna. Ofta räcker det att stirra motståndaren i ansiktet men ibland hoppar de på varandra eller slår och biter. I vissa fall eskalerar dessa möten och enskilda individer såras eller dödas. Efteråt vistas varje grupp vanligen i centrum av sitt revir.
Referenser
Noter
Externa länkar
Lemurer
Däggdjur i etiopiska regionen | swedish | 1.048378 |
insescts_six_legs/eli5howdoinsectlegsw.txt | Skip to main content
Open menu Open navigation [ ](/) Go to Reddit Home
r/explainlikeimfive A chip A close button
Get app Get the Reddit app [ Log In ](https://www.reddit.com/login/) Log in
to Reddit
Expand user menu Open settings menu
* [ Log In / Sign Up ](https://www.reddit.com/login/)
* [ Advertise on Reddit ](https://ads.reddit.com?utm_source=web3x_consumer&utm_name=user_menu_cta)
* [ Shop Collectible Avatars ](/avatar/shop)
### Get the Reddit app
Scan this QR code to download the app now
Or check it out in the app stores
[ ](https://play.google.com/store/apps/details?id=com.reddit.frontpage) [
](https://apps.apple.com/US/app/id1064216828)
[ Go to explainlikeimfive ](/r/explainlikeimfive/)
[ r/explainlikeimfive ](/r/explainlikeimfive/)
[ r/explainlikeimfive ](/r/explainlikeimfive/)
Explain Like I'm Five is the best forum and archive on the internet for
layperson-friendly explanations. Don't Panic!
* * *
Members Online
•
[ KlaraNovakRocks ](/user/KlaraNovakRocks/)
ADMIN MOD
# ELI5: How do insect legs work, do they have something like muscle?
[ Biology ](/r/explainlikeimfive/?f=flair_name%3A%22Biology%22)
Archived post. New comments cannot be posted and votes cannot be cast.
** ** [ Rank by size ](https://www.reddit.com/best/communities/1/#t5_2sokd/)
## Top Posts
* * *
* [ Reddit reReddit: Top posts of June 28, 2022
* * *
](https://www.reddit.com/posts/2022/june-28-1/)
* [ Reddit reReddit: Top posts of June 2022
* * *
Skip to main content
ELI5: How do insect legs work, do they have something like muscle? : r/explainlikeimfive
r/explainlikeimfive
Current search is within r/explainlikeimfive
Remove r/explainlikeimfive filter and expand search to all of Reddit
Search in r/explainlikeimfive
Get app
Log In
Expand user menu
Skip to NavigationSkip to Right Sidebar
Back
r/explainlikeimfive icon
Go to explainlikeimfive
r/explainlikeimfive
•
2 yr. ago
KlaraNovakRocks
ELI5: How do insect legs work, do they have something like muscle?
Biology
Archived post. New comments cannot be posted and votes cannot be cast.
Upvote
381
Downvote
37
comments
Share
Share
Avatar for solidigm
u/solidigm
•
Promoted
Ad Post Creative Image Thumbnail
SSDs may hold the key to efficient AI. Say goodbye to hard drive limitations on performance and scalability while optimizing your total cost of ownership and sustainability.
solidigm.com
Learn More
Sort by:
Best
Fredrules2012
•
2y ago
Even cooler, hydraulics. They fill the chambers of their limbs with fluid and that's how bugs hippy hop so strongly and flippy flap so quickly
Upvote
612
Downvote
Share
Share
u/KlaraNovakRocks avatar
KlaraNovakRocks
OP
•
2y ago
What drives the "pump" and valves? Do they have circulation? Something in there moves the liquid
Upvote
102
Downvote
Share
Share
15 more replies
u/pewpewyouuk avatar
pewpewyouuk
•
2y ago
Also swimmy swim
Upvote
42
Downvote
Share
Share
[deleted]
Lord-Wombat
•
2y ago
Metal
Upvote
10
Downvote
Share
Share
Blythyvxr
•
2y ago
This supports my theory that insects are 90% goo
Upvote
5
Downvote
Share
Share
5 more replies
u/AdoraBellDearheart avatar
AdoraBellDearheart
•
2y ago
Grasshoppers, for example have muscles and they work very similarly to mammalian muscles
https://ib.bioninja.com.au/higher-level/topic-11-animal-physiology/112-movement/muscles.html
Upvote
18
Downvote
Share
Share
u/IntelligentAppeal384 avatar
IntelligentAppeal384
•
2y ago
While on the topic, what causes a bugs legs to curl up when it dies?
Edit: nvm. I just got the brilliant idea to read the other comment in this post.
Upvote
48
Downvote
Share
Share
u/AgoraiosBum avatar
AgoraiosBum
•
2y ago
Boneitis
Upvote
41
Downvote
Share
Share
2 more replies
apple-masher
•
2y ago
Not all insect legs work the same way.
Most insects have muscles, but they are on the inside of the exoskeleton.
some insects, and most spiders, use fluid pressure (hydraulics) to extend (straighten) their legs, and muscles to flex (bend) their legs.
And many insects have spring-loaded legs, so they use muscles to flex, and the springiness of their exoskeleton to extend their legs.
Upvote
9
Downvote
Share
Share
u/FullCloud avatar
FullCloud
•
2y ago
I read the title "incest legs" and got confused, so I went to read the comments to know what that is. I started reading and found bugs, hydraulics, legs curling up and I got even more confused. I re-read the title and I must say I'm now more relieved.
Upvote
11
Downvote
Share
Share
1 more reply
[deleted]
•
2y ago
r/explainlikeimfive
Join
Explain Like I'm Five | Don't Panic!
Explain Like I'm Five is the best forum and archive on the internet for layperson-friendly explanations. Don't Panic!
23M
Members
2.4K
Online
24
Rank by size
r/40kLore icon
r/40kLore
Do Orks need nutrients to grow? Or do they just ignore physics and grow anyways?
12 upvotes · 7 comments
r/explainlikeimfive icon
r/explainlikeimfive
ELI5: How does a knuckleball wobble when (generally speaking) the wind is blowing consistently in one direction?
134 upvotes · 35 comments
r/zoology
What are these spider-like animals?
r/zoology - What are these spider-like animals?
66 upvotes · 5 comments
r/explainlikeimfive icon
r/explainlikeimfive
ELI5: What would happen if you had a cord long enough to be in space and earth? (For example tying a cord onto a satellite long enough to touch the ground on earth would it appear to float?)
230 upvotes · 109 comments
r/Justrolledintotheshop
Well that's not supposed to happen...
348 upvotes · 37 comments
r/shittyrobots
Rice University mechanical engineers are showing how to repurpose deceased spiders as mechanical grippers that can blend into natural environments while picking up objects, like other insects, that outweigh them.
2.1K upvotes · 71 comments
r/memes
Even in death they’re mad freaky
27K upvotes · 104 comments
r/spiders
Can anyone explain the abdomen movement? Cbus, Ohio
0:13
332 upvotes · 66 comments
r/explainlikeimfive
Eli5: How was the first diamond cutter created?
218 upvotes · 47 comments
r/explainlikeimfive
ELI5 - Why does the light from a laser pointer look "grainy"? Like it is made up of a bunch of little dots?
411 upvotes · 48 comments
r/biology
Why don't birds have testicles?
4 upvotes · 10 comments
r/NatureIsFuckingLit
🔥 A spider/frog fight lost by both opponent
20K upvotes · 300 comments
r/explainlikeimfive
eli5 How does an Electric Eel shock you? Don’t you need to complete a circuit for the current to flow through you?
753 upvotes · 124 comments
r/explainlikeimfive
ELI5: Why do things that use suction cups work better with water?
102 upvotes · 15 comments
r/explainlikeimfive
ELI5: What technology is in the bearings of wheels of cars/bicycles such that they are used in the rain without worrying about corrosion? Asking because everyone just told me skateboard/roller skate wheel bearings would rust if I skate in the rain, or just going through a puddle would ruin them.
385 upvotes · 47 comments
r/interestingasfuck
Ribbon Jellies are so fragile that the waves of the shore would destroy them, so you can only find them in calm open ocean waters.
gfycat
1.3K upvotes · 19 comments
r/Showerthoughts
Human fingers don’t have any muscles in them. Your palm and forearm are literally pulling the strings.
829 upvotes · 120 comments
r/explainlikeimfive
ELI5: what happens if a muscle knot is never released?
15 upvotes · 25 comments
r/explainlikeimfive
Eli5 Why can’t a person live on multivitamins and workout shakes?
1.1K upvotes · 552 comments
r/explainlikeimfive
ELI5: how does pounding on my baby's back soothe it to sleep?
12 upvotes · 13 comments
r/explainlikeimfive
ELI5: Why do teeth need nerves?
311 upvotes · 81 comments
r/explainlikeimfive
ELI5: How do distilled spirits retain flavors from alcohol before distillation?
123 upvotes · 30 comments
r/fishtank
Strange Tetra likes to lay down on plants
3
12 upvotes · 12 comments
r/explainlikeimfive
eli5 How does Queen Ants get so big? Do they just live longer? Is it that royalty bloodline? She just eat a lot more?
5.7K upvotes · 359 comments
r/FantasyWorldbuilding
My fantasy race The Corrodics ask me anything and I’ll try to answer
132 upvotes · 56 comments
TOP POSTS
Reddit
reReddit: Top posts of June 28, 2022
Reddit
reReddit: Top posts of June 2022
Reddit
reReddit: Top posts of 2022
](https://www.reddit.com/posts/2022/june/)
* [ Reddit reReddit: Top posts of 2022
* * *
](https://www.reddit.com/posts/2022/)
*
*
* * *
* TOPICS
* Gaming
* [ Valheim ](https://reddit.com/t/valheim/)
* [ Genshin Impact ](https://reddit.com/t/genshin_impact/)
* [ Minecraft ](https://reddit.com/t/minecraft/)
* [ Pokimane ](https://reddit.com/t/pokimane/)
* [ Halo Infinite ](https://reddit.com/t/halo_infinite/)
* [ Call of Duty: Warzone ](https://reddit.com/t/call_of_duty_warzone/)
* [ Path of Exile ](https://reddit.com/t/path_of_exile/)
* [ Hollow Knight: Silksong ](https://reddit.com/t/hollow_knight_silksong/)
* [ Escape from Tarkov ](https://reddit.com/t/escape_from_tarkov/)
* [ Watch Dogs: Legion ](https://reddit.com/t/watch_dogs_legion/)
* Sports
* [ NFL ](https://reddit.com/t/nfl/)
* [ NBA ](https://reddit.com/t/nba/)
* [ Megan Anderson ](https://reddit.com/t/megan_anderson/)
* [ Atlanta Hawks ](https://reddit.com/t/atlanta_hawks/)
* [ Los Angeles Lakers ](https://reddit.com/t/los_angeles_lakers/)
* [ Boston Celtics ](https://reddit.com/t/boston_celtics/)
* [ Arsenal F.C. ](https://reddit.com/t/arsenal_fc/)
* [ Philadelphia 76ers ](https://reddit.com/t/philadelphia_76ers/)
* [ Premier League ](https://reddit.com/t/premier_league/)
* [ UFC ](https://reddit.com/t/ufc/)
* Business
* [ GameStop ](https://reddit.com/t/gamestop/)
* [ Moderna ](https://reddit.com/t/moderna/)
* [ Pfizer ](https://reddit.com/t/pfizer/)
* [ Johnson & Johnson ](https://reddit.com/t/johnson_johnson/)
* [ AstraZeneca ](https://reddit.com/t/astrazeneca/)
* [ Walgreens ](https://reddit.com/t/walgreens/)
* [ Best Buy ](https://reddit.com/t/best_buy/)
* [ Novavax ](https://reddit.com/t/novavax/)
* [ SpaceX ](https://reddit.com/t/spacex/)
* [ Tesla ](https://reddit.com/t/tesla/)
* Crypto
* [ Cardano ](https://reddit.com/t/cardano/)
* [ Dogecoin ](https://reddit.com/t/dogecoin/)
* [ Algorand ](https://reddit.com/t/algorand/)
* [ Bitcoin ](https://reddit.com/t/bitcoin/)
* [ Litecoin ](https://reddit.com/t/litecoin/)
* [ Basic Attention Token ](https://reddit.com/t/basic_attention_token/)
* [ Bitcoin Cash ](https://reddit.com/t/bitcoin_cash/)
* Television
* [ The Real Housewives of Atlanta ](https://reddit.com/t/the_real_housewives_of_atlanta/)
* [ The Bachelor ](https://reddit.com/t/the_bachelor/)
* [ Sister Wives ](https://reddit.com/t/sister_wives/)
* [ 90 Day Fiance ](https://reddit.com/t/90_day_fiance/)
* [ Wife Swap ](https://reddit.com/t/wife_swap/)
* [ The Amazing Race Australia ](https://reddit.com/t/the_amazing_race_australia/)
* [ Married at First Sight ](https://reddit.com/t/married_at_first_sight/)
* [ The Real Housewives of Dallas ](https://reddit.com/t/the_real_housewives_of_dallas/)
* [ My 600-lb Life ](https://reddit.com/t/my_600lb_life/)
* [ Last Week Tonight with John Oliver ](https://reddit.com/t/last_week_tonight_with_john_oliver/)
* Celebrity
* [ Kim Kardashian ](https://reddit.com/t/kim_kardashian/)
* [ Doja Cat ](https://reddit.com/t/doja_cat/)
* [ Iggy Azalea ](https://reddit.com/t/iggy_azalea/)
* [ Anya Taylor-Joy ](https://reddit.com/t/anya_taylorjoy/)
* [ Jamie Lee Curtis ](https://reddit.com/t/jamie_lee_curtis/)
* [ Natalie Portman ](https://reddit.com/t/natalie_portman/)
* [ Henry Cavill ](https://reddit.com/t/henry_cavill/)
* [ Millie Bobby Brown ](https://reddit.com/t/millie_bobby_brown/)
* [ Tom Hiddleston ](https://reddit.com/t/tom_hiddleston/)
* [ Keanu Reeves ](https://reddit.com/t/keanu_reeves/)
* * *
* RESOURCES
* [ About Reddit ](https://www.redditinc.com)
* [ Advertise ](https://ads.reddit.com?utm_source=web3x_consumer&utm_name=left_nav_cta)
* [ Help ](https://www.reddithelp.com)
* [ Blog ](https://redditblog.com/)
* [ Careers ](https://www.redditinc.com/careers)
* [ Press ](https://www.redditinc.com/press)
* * *
* [ Communities ](https://www.reddit.com/best/communities/1/)
* [ Best of Reddit ](https://www.reddit.com/posts/2024/global/)
* [ Topics ](https://www.reddit.com/topics/a-1/)
* * *
* [ Content Policy ](https://www.redditinc.com/policies/content-policy)
* [ Privacy Policy ](https://www.reddit.com/policies/privacy-policy)
* [ User Agreement ](https://www.redditinc.com/policies/user-agreement)
[ Reddit, Inc. © 2024. All rights reserved. ](https://redditinc.com)
| biology | 8689704 | https://sv.wikipedia.org/wiki/Lista%20%C3%B6ver%20f%C3%A5gelarter%20beskrivna%20under%202020-talet | Lista över fågelarter beskrivna under 2020-talet | Detta är en lista över fågelarter som beskrivits som nya för vetenskapen under 2020-talet. För fågelarter beskrivna under 2010-talet, se denna lista.
Arter, år för år
2020
Pelengsolfjäderstjärt (Rhipidura habibiei) : Frank E. Rheindt, Dewi M. Prawiradilaga, Hidayat Ashari, Suparno, Chyi Yin Gwee, Geraldine W. X. Lee, Meng Yue Wu, Nathaniel S. R. Ng. "A lost world in Wallacea: Description of a montane archipelagic avifauna". Science, 2020 DOI: 10.1126/science.aax2146
Taliabusmygsångare (Locustella portenta) : Frank E. Rheindt, Dewi M. Prawiradilaga, Hidayat Ashari, Suparno, Chyi Yin Gwee, Geraldine W. X. Lee, Meng Yue Wu, Nathaniel S. R. Ng. "A lost world in Wallacea: Description of a montane archipelagic avifauna". Science, 2020 DOI: 10.1126/science.aax2146
Taliabumyzomela (Myzomela wahe) : Frank E. Rheindt, Dewi M. Prawiradilaga, Hidayat Ashari, Suparno, Chyi Yin Gwee, Geraldine W. X. Lee, Meng Yue Wu, Nathaniel S. R. Ng. "A lost world in Wallacea: Description of a montane archipelagic avifauna". Science, 2020 DOI: 10.1126/science.aax2146
Phylloscopus suaramerdu : Frank E. Rheindt, Dewi M. Prawiradilaga, Hidayat Ashari, Suparno, Chyi Yin Gwee, Geraldine W. X. Lee, Meng Yue Wu, Nathaniel S. R. Ng. "A lost world in Wallacea: Description of a montane archipelagic avifauna". Science, 2020 DOI: 10.1126/science.aax2146
Phylloscopus emilsalimi : Frank E. Rheindt, Dewi M. Prawiradilaga, Hidayat Ashari, Suparno, Chyi Yin Gwee, Geraldine W. X. Lee, Meng Yue Wu, Nathaniel S. R. Ng. "A lost world in Wallacea: Description of a montane archipelagic avifauna". Science, 2020 DOI: 10.1126/science.aax2146
Vitvingetapakul (Scytalopus krabbei) : Krabbe, Niels K.; Schulenberg, Thomas S.; Hosner, Peter A.; Rosenberg, Kenneth V.; Davis, Tristan J.; Rosenberg, Gary H.; Lane, Daniel F.; Andersen, Michael J.; Robbins, Mark B.; Cadena, Carlos Daniel; Valqui, Thomas. "Untangling cryptic diversity in the High Andes: Revision of the Scytalopus [magellanicus] complex (Rhinocryptidae) in Peru reveals three new species". The Auk. Doi:10.1093/auk/ukaa003.
Jalkatapakul (Scytalopus frankeae) : Krabbe, Niels K.; Schulenberg, Thomas S.; Hosner, Peter A.; Rosenberg, Kenneth V.; Davis, Tristan J.; Rosenberg, Gary H.; Lane, Daniel F.; Andersen, Michael J.; Robbins, Mark B.; Cadena, Carlos Daniel; Valqui, Thomas. "Untangling cryptic diversity in the High Andes: Revision of the Scytalopus [magellanicus] complex (Rhinocryptidae) in Peru reveals three new species". The Auk. Doi:10.1093/auk/ukaa003.
Ampaytapakul (Scytalopus whitneyi) : Krabbe, Niels K.; Schulenberg, Thomas S.; Hosner, Peter A.; Rosenberg, Kenneth V.; Davis, Tristan J.; Rosenberg, Gary H.; Lane, Daniel F.; Andersen, Michael J.; Robbins, Mark B.; Cadena, Carlos Daniel; Valqui, Thomas. "Untangling cryptic diversity in the High Andes: Revision of the Scytalopus [magellanicus] complex (Rhinocryptidae) in Peru reveals three new species". The Auk. Doi:10.1093/auk/ukaa003.
Chamímyrpitta (Grallaria alvarezi) : Morton L. Isler, R. Terry Chesser, Mark B. Robbins, Andrés M. Cuervo, Carlos Daniel Cadena and Peter A. Hosner. 2020. Taxonomic Evaluation of the Grallaria rufula (Rufous Antpitta) Complex (Aves: Passeriformes: Grallariidae) distinguishes Sixteen Species. Zootaxa. 4817(1); 1-74. DOI: 10.11646/zootaxa.4817.1.1
Chachapoyasmyrpitta (Grallaria gravesi) : Morton L. Isler, R. Terry Chesser, Mark B. Robbins, Andrés M. Cuervo, Carlos Daniel Cadena and Peter A. Hosner. 2020. Taxonomic Evaluation of the Grallaria rufula (Rufous Antpitta) Complex (Aves: Passeriformes: Grallariidae) distinguishes Sixteen Species. Zootaxa. 4817(1); 1-74. DOI: 10.11646/zootaxa.4817.1.1
Panaomyrpitta (Grallaria oneilli) : Morton L. Isler, R. Terry Chesser, Mark B. Robbins, Andrés M. Cuervo, Carlos Daniel Cadena and Peter A. Hosner. 2020. Taxonomic Evaluation of the Grallaria rufula (Rufous Antpitta) Complex (Aves: Passeriformes: Grallariidae) distinguishes Sixteen Species. Zootaxa. 4817(1); 1-74. DOI: 10.11646/zootaxa.4817.1.1
Oxapampamyrpitta (Grallaria centralis) : Morton L. Isler, R. Terry Chesser, Mark B. Robbins, Andrés M. Cuervo, Carlos Daniel Cadena and Peter A. Hosner. 2020. Taxonomic Evaluation of the Grallaria rufula (Rufous Antpitta) Complex (Aves: Passeriformes: Grallariidae) distinguishes Sixteen Species. Zootaxa. 4817(1); 1-74. DOI: 10.11646/zootaxa.4817.1.1
Ayacuchomyrpitta (Grallaria ayacuchensis) : Morton L. Isler, R. Terry Chesser, Mark B. Robbins, Andrés M. Cuervo, Carlos Daniel Cadena and Peter A. Hosner. 2020. Taxonomic Evaluation of the Grallaria rufula (Rufous Antpitta) Complex (Aves: Passeriformes: Grallariidae) distinguishes Sixteen Species. Zootaxa. 4817(1); 1-74. DOI: 10.11646/zootaxa.4817.1.1
Punomyrpitta (Grallaria sinaensis) : Morton L. Isler, R. Terry Chesser, Mark B. Robbins, Andrés M. Cuervo, Carlos Daniel Cadena and Peter A. Hosner. 2020. Taxonomic Evaluation of the Grallaria rufula (Rufous Antpitta) Complex (Aves: Passeriformes: Grallariidae) distinguishes Sixteen Species. Zootaxa. 4817(1); 1-74. DOI: 10.11646/zootaxa.4817.1.1
Pygoscelis poncetti : Joshua Tyler, Matthew T. Bonfitto, Gemma V. Clucas, Sushma Reddy and Jane L. Younger. 2020. Morphometric and Genetic Evidence for Four Species of Gentoo Penguin. Ecology and Evolution. DOI: 10.1002/ece3.6973
2021
Megascops stangiae : Dantas, Sidnei M.; Weckstein, Jason D.; Bates, John; Oliveira, Joiciane N.; Catanach, Therese A.; Aleixo, Alexandre (26 March 2021). "Multi-character taxonomic review, systematics, and biogeography of the Black-capped/Tawny-bellied Screech Owl ( Megascops atricapilla - M. watsonii ) complex (Aves: Strigidae)". Zootaxa. 4949 (3): 401–444. Doi:10.11646/zootaxa.4949.3.1. ISSN 1175-5334.
Megascops alagoensis : Dantas, Sidnei M.; Weckstein, Jason D.; Bates, John; Oliveira, Joiciane N.; Catanach, Therese A.; Aleixo, Alexandre (26 March 2021). "Multi-character taxonomic review, systematics, and biogeography of the Black-capped/Tawny-bellied Screech Owl ( Megascops atricapilla - M. watsonii ) complex (Aves: Strigidae)". Zootaxa. 4949 (3): 401–444. Doi:10.11646/zootaxa.4949.3.1. ISSN 1175-5334.
Trogon muriciensis : Dickens, Jeremy Kenneth; Bitton, Pierre-Paul; Bravo, Gustavo A; Silveira, Luís Fábio (2021-03-06). "Species limits, patterns of secondary contact and a new species in the Trogon rufus complex (Aves: Trogonidae)". Zoological Journal of the Linnean Society: –169. Doi:10.1093/zoolinnean/zlaa169. ISSN 0024-4082.
Kilomberocistikola (Cisticola bakerorum) : Jon Fjeldså, Lars Dinesen, Owen R. Davies, Martin Irestedt, Niels K. Krabbe, Louis A. Hansen and Rauri C. K. Bowie. 2021. Description of Two New Cisticola Species Endemic to the Marshes of the Kilombero Floodplain of southwestern Tanzania. Ibis. DOI: 10.1111/ibi.12971
Vitstjärtad cistikola (Cisticola anderseni) : Jon Fjeldså, Lars Dinesen, Owen R. Davies, Martin Irestedt, Niels K. Krabbe, Louis A. Hansen and Rauri C. K. Bowie. 2021. Description of Two New Cisticola Species Endemic to the Marshes of the Kilombero Floodplain of southwestern Tanzania. Ibis. DOI: 10.1111/ibi.12971
Kumawabärpickare (Melanocharis citreola) : Borja Milá, Jade Bruxaux, Guillermo Friis, Katerina Sam, Hidayat Ashari and Christophe Thébaud. 2021. A New, Undescribed Species of Melanocharis Berrypecker from western New Guinea and the Evolutionary History of the Family Melanocharitidae. Ibis. DOI: 10.1111/ibi.12981
Heliothraupis oneilli : Daniel F. Lane, Miguel Angel Aponte Justiniano, Ryan S. Terrill, Frank E. Rheindt, Luke B. Klicka, Gary H. Rosenberg, C. Jonathan Schmitt, Kevin J. Burns. 2021. A new genus and species of tanager (Passeriformes, Thraupidae) from the lower Yungas of western Bolivia and southern Peru. Ornithology DOI: 10.1093/ornithology/ukab059
2022
"Diegoramireztörnstjärt" (Aphrastura subantarctica) : Ricardo Rozzi, Claudio S. Quilodrán, Esteban Botero-Delgadillo, Constanza Napolitano, Juan C. Torres-Mura, Omar Barroso, Ramiro D. Crego, Camila Bravo, Silvina Ippi, Verónica Quirici, Roy Mackenzie, Cristián G. Suazo, Juan Rivero-de-Aguilar, Bernard Goffinet, Bart Kempenaers, Elie Poulin & Rodrigo A. Vásquez (2022-08-26) The Subantarctic Rayadito (Aphrastura subantarctica), a new bird species on the southernmost islands of the Americas. Scientific Reports. DOI: https://doi.org/10.1038/s41598-022-17985-4
Referenser
Texten bygger på en översättning av engelskspråkiga wikipedias artikel List of bird species described in the 2020s, läst 25 september 2022
Fåglar
Listor med anknytning till biologi | swedish | 1.211703 |
drink_sea_water/osmolality_of_human_blood.txt | Osmolality of human blood
Range 275-299 mOsm/kg
Organism Human Homo sapiens
Reference link top paragraph
Entered by Ron Milo - Admin
ID 100803 | biology | 4209409 | https://sv.wikipedia.org/wiki/Sarcoglottis%20homalogastra | Sarcoglottis homalogastra | Sarcoglottis homalogastra är en orkidéart som först beskrevs av Heinrich Gustav Reichenbach och Johannes Eugen ius Bülow Warming, och fick sitt nu gällande namn av Rudolf Schlechter. Sarcoglottis homalogastra ingår i släktet Sarcoglottis och familjen orkidéer. Inga underarter finns listade i Catalogue of Life.
Källor
Orkidéer
homalogastra | swedish | 1.21557 |
drink_sea_water/osmolarity_of_sea_water.txt | Osmolarity of sea water
Value 1000 mOsm/l
Organism Biosphere
Reference Peter J. Russell,Stephen L. Wolfe,Paul E. Hertz,Cecie Starr, Biology: The Dynamic Science, chapter 46 Regulating the internal environment p.1041 top paragraph fig.46.1
Comments contributing ions (in mOsm) Na 459 K 10 Ca 10 Mg 53 Cl 538
Entered by Ron Milo - Admin
ID 100802 | biology | 1040866 | https://sv.wikipedia.org/wiki/Carl%20Folke | Carl Folke | Carl Folke, född 1955, är en svensk ekolog och ekonom. Han är professor och föreståndare för Beijerinstitutet vid Kungliga Vetenskapsakademien och grundare av och styrelseordförande för Stockholm Resilience Centre vid Stockholms universitet. Folke är medlem av Kungliga Vetenskapsakademien (2002), National Academy of Sciences, USA (2017), Det Kongelige Norske Videnskabers Selskab (2017), och Kungl. Skogs och Lantbruksakademien (2017). Han är Kabinettskammarherre i Ceremonistaten vid Kungliga Hovstaterna.
Karriär
Carl Folke är forskare inom resiliens och tvärvetenskaplig miljöforskning med fokus på hållbar utveckling. Hans forskningsområden inkluderar ekosystem såsom haven, korallrev och våtmarker, samt ämnen som vattenfrågor, matproduktion, urbanisering, adaptiv samförvaltning och finansmarknader. Han har bidragit till att betona vikten av att länka samhällsutvecklingen till biosfären och att utveckla strategier för att hantera miljöförändringar inom planetens gränser.
Folke fick sin doktorsexamen i systemekologi, med inriktning på ekologisk ekonomi, vid Stockholms universitet 1990. Han var vice-chef för Beijerinstitutet mellan 1991 och 1996, blev utnämnd till professor i "natural resource management" vid systemekologiska institutionen 1996, och var föreståndare vid Centrum för tvärvetenskaplig miljöforskning 1999-2006. År 2006 blev han chef för Beijerinstitutet, och 2007 var han med och startade Stockholm Resilience Centre, där han fungerar som forskningschef sedan 2007 och styrelseordförande från 2019.
Utöver sin akademiska karriär har Folke även varit involverad i projekt som utforskar samspelet mellan konst och vetenskap, inklusive utställningar på Artipelag, Raoul Wallenbergs Torg, Naturhistoriska Riksmuseet. Han har även ett samarbete med Svenskt Tenn.
Utmärkelser
H.M. Konungens medalj i guld av 8:e storleken i Serafimerordens band (Kon:sGM8mserafb, 2018)
Ledamot av Kungl. Vetenskapsakademien (LVA, 2002) som ledamot nummer 1471
Ledamot av Amerikanska Vetenskapsakademien (LAmVA, 2017)
Hedersdoktor vid KU Leuven, Belgien (2015), Michigan State University, East Lansing, USA (2017) och Wageningen University and Research, Holland (2018)
Priser
Dr A.H. Heineken Prize for Environmental Sciences, 2022
Grande Médaille Albert Ier, Science, Institut Océanographique de Monaco, 2021
Gunneruspriset i Sustainability Science, 2017
International Geographical Union‘s Planet and Humanity Medal, 2016
The 2004 Sustainability Science Award of the Ecological Society of America
Pew Scholar in Conservation and the Environment, 1995
Publikationer
Carl Folke har publicerat över 350 vetenskapliga arbeten och ett dussin böcker.
Urval av böcker
Berkes, F. and C. Folke. 1998. Linking Social and Ecological Systems: Management Practices and Social Mechanisms for Building Resilience. Cambridge University Press.
Berkes, F., J. Colding and C. Folke. 2003. Navigating Social-Ecological Systems: Building Resilience for Complexity and Change. Cambridge University Press.
Chapin, F.S, III, G.P. Kofinas and C. Folke. 2009. Principles of Ecosystem Stewardship: Resilience-Based Natural Resource Management in a Changing World. Springer Verlag.
Barbier, E.B., J. Burgess and C. Folke. 1994. Paradise Lost? The Ecological Economics of Biodiversity. Earthscan. Reprinted by Routledge 2019.
Jansson, A.M., M. Hammer, C. Folke, and R. Costanza. 1994. Investing in Natural Capital: The Ecological Economics Approach to Sustainability. Island Press.
Folke, C. och L. Hall. 2014. Speglingar: Om Människan och Biosfären. Bokförlaget Langenskiöld, Stockholm.
Urval publikationer
Folke, C., S. Polasky, J. Rockström, V. Galaz, F. Westley, M. Lamont, M. Scheffer, H. Österblom, et al. 2021. Our Future in the Anthropocene Biosphere. Ambio 50: 834-869. https://doi10.1007/s13280-021-01544-8
Folke, C. 2006. Resilience: Emergence of a Perspective for Social-Ecological Systems Analyses. Global Environmental Change 16: 253-267. https://doi.org/10.1016/j.gloenvcha.2006.04.002
Folke, C., T. Hahn, P. Olsson and J. Norberg. 2005. Adaptive Governance of Social-Ecological Systems. Annual Review of Environment and Resources 30:441-473. https://doi.org/10.1146/annurev.energy.30.050504.144511
Folke, C., R. Biggs, A. Norström, B. Reyers, and J. Rockström. 2016. Social-Ecological Resilience and Biosphere-Based Sustainability Science. Ecology and Society 21(3):41. http://dx.doi.org/10.5751/ES-08748-210341
Folke, C., S.R. Carpenter, B. Walker, M. Scheffer, T. Elmqvist, L. Gunderson and C.S. Holling. 2004. Regime Shifts, Resilience and Biodiversity in Ecosystem Management. Annual Review of Ecology, Evolution and Systematics 35:557-581. https://doi.org/10.1146/annurev.ecolsys.35.021103.105711
Scheffer, M., Carpenter, S., Foley, J., Folke, C. and Walker, B. 2001. Catastrophic Shifts in Ecosystems. Nature 413:591-596. https://doi.org/10.1038/35098000
Rockström, J. W. Steffen, K. Noone, Å. Persson, F.S. Chapin III, E.F. Lambin, T.M. Lenton, M. Scheffer, C. Folke, et al.. 2009. A Safe Operating Space for Humanity. Nature 461:472-475. https://doi.org/10.1038/461472a
Nyström M., J.-B. Jouffray, A. Norström, P. Sogaard-Jørgensen, V. Galaz, B.E. Crona, S.R. Carpenter, and C. Folke. 2019. Anatomy and Resilience of the Global Production Ecosystem. Nature 575: 98-108. https://doi.org/10.1038/s41586-019-1712-3
Liu, J., T. Dietz, S.R. Carpenter, M. Alberti, C. Folke, E. Moran, A.C. Pell, P. Deadman, T. Kratz, J. Lubchenco, E. Ostrom, et al. 2007. Complexity of Coupled Human and Natural Systems. Science 317:1513-1516. DOI: 10.1126/science.1144004
Olsson, P., C. Folke and T. Hahn. 2004. Social-Ecological Transformation for Ecosystem Management: The Development of Adaptive Co-Management of a Wetland Landscape in Southern Sweden. Ecology and Society 9(4): 2. http://www.ecologyandsociety.org/vol9/iss4/art2
Westley, F., P. Olsson, C. Folke, T. Homer-Dixon, et al. 2011. Tipping Towards Sustainability: Emerging Pathways of Transformation. Ambio 40:762-780. DOI 10.1007/s13280-011-0186-9
Arrow, K., B. Bolin, R. Costanza, P. Dasgupta, C. Folke, C.S. Holling, B.-O. Jansson, S. Levin, et al. 1995. Economic Growth, Carrying Capacity, and the Environment. Science 268:520-521. DOI: 10.1126/science.268.5210.520
Daily, G., T. Söderqvist, S. Aniyar, K. Arrow, P. Dasgupta, P.R. Ehrlich, C. Folke, et al. 2000. The Value of Nature and the Nature of Value? Science 289:395-396. DOI: 10.1126/science.289.5478.395
Folke, C., Å. Jansson, J. Larsson and R. Costanza. 1997. Ecosystem Appropriation by Cities. Ambio 26:167-172. http://www.jstor.org/stable/4314576
Moberg, F. and C. Folke. 1999. Ecological Services of Coral Reef Ecosystems. Ecological Economics 29:215-233. https://doi.org/10.1016/S0921-8009(99)00009-9
Bellwood, D., T. Hughes, C. Folke and M. Nyström. 2004. Confronting the Coral Reef Crisis. Nature 429:827-833. https://doi.org/10.1038/nature02691
Worm, B., E.B. Barbier, N. Beaumont, J.E. Duffy, C. Folke, B.S. Halpern. J.B.C. Jackson, et al. 2006. Impacts of Biodiversity Loss on Ocean Ecosystem Services. Science 314:787-790. doi: 10.1126/science.1132294
Folke. C., and N. Kautsky. 1989. The Role of Ecosystems for a Sustainable Development of Aquaculture. Ambio 18:234-243. https://www.jstor.org/stable/4313572
Naylor, R., R. Goldburg, J. Primavera, N. Kautsky, M. Beveridge, J. Clay, C. Folke, J. Lubchenco, H. Mooney, and M. Troell. 2000. Effect of Aquaculture on World Fish Supplies. Nature 405:1017-1024. https://doi.org/10.1038/35016500
Österblom, H., C. Folke, J.-B. Jouffray, and J. Rockström. 2017. Emergence of a Global Science-Business Initiative for Ocean Stewardship. Proceedings of the National Academy of Sciences, USA. doi/10.1073/pnas.1704453114
Österblom, H. C. Folke, J. Rocha, J. Bebbington, R. Blasiak, J.-B. Jouffray, E.R. Selig, C.C.C. Wabnitz, et al. 2022. Scientific Mobilization of Keystone Actors for Biosphere Stewardship. Scientific Reports 12:3802. https://doi.org/10.1038/s41598-022-07023-8
Folke, C., H. Österblom, J.-B. Jouffray, E. Lambin, M. Scheffer, B.I. Crona, M. Nyström, S.A. Levin, et al. 2019. Transnational Corporations and the Challenge of Biosphere Stewardship. Nature Ecology & Evolution 3:1396–1403. doi 10.1038/s41559-019-0978-z
Rockström, J., T. Beringer, D. Hole, B. Griscom, M. Mascia, C. Folke, and F. Creutzig. 2021. We need Biosphere Stewardship that Protects Carbon Sinks and Builds Resilience. Proceedings of the National Academy of Sciences, USA 118 No. 38 e2115218118. https://doi.org/10.1073/pnas.2115218118
Gadgil, M., F. Berkes, and C. Folke. 1993. Indigenous Knowledge for Biodiversity Conservation. Ambio 22:151-156. https://www.jstor.org/stable/4314060
Berkes, F., C. Folke and J. Colding. 2000. Rediscovery of Traditional Ecological Knowledge as Adaptive Management. Ecological Applications 10:1251-1262. https://doi.org/10.1890/1051-0761(2000)010[1251:ROTEKA]2.0.CO;2
Schill, C., J.M. Anderies, T. Lindahl, C. Folke, S. Polasky, J.-C. Cárdenas, A.-S. Crépin, M. Jansen, J. Norberg, and M. Schlüter. 2019. A More Dynamic Understanding of Human Behaviour for the Anthropocene. Nature Sustainability 2:1075-1082. https://doi.org/10.1038/s41893-019-0419-7
Jørgensen, P.S., C. Folke, and S.C. Carroll. 2019. Evolution in the Anthropocene: Informing Governance and Policy. Annual Review of Ecology, Evolution and Systematics 50: 527-546. https://doi.org/10.1146/annurev-ecolsys-110218-024621
Steffen, W., J. Rockström, K. Richardson, T.M. Lenton, C. Folke, et al. 2018. Trajectories of the Earth System in the Anthropocene. Proceedings of the National Academy of Sciences, USA, 115:8252-8259. https://doi.org/10.1073/pnas.1810141115
Reyers, B., C. Folke, M.-L. Moore, R. Biggs, and V. Galaz. 2018. Social-Ecological Systems Insights for Navigating the Dynamics of the Anthropocene. Annual Review of Environment and Resources 43:267–289. https://doi.org/10.1146/annurev-environ-110615-085349
Crona, B.I., C. Folke, and V. Galaz. 2021. The Anthropocene Reality of Financial Risk. One Earth 4(5): 619-628. https://doi.org/10.1016/j.oneear.2021.04.016
Externa länkar
Referenser
Svenska professorer i ekologi
Personer verksamma vid Stockholms universitet
Ledamöter av Kungliga Vetenskapsakademien
Män
Födda 1955
Levande personer
Kabinettskammarherrar | swedish | 0.650392 |
neurons_learn/Neural_network_(machine_learning).txt | Jump to content
Main menu
Main menu
move to sidebar hide
Navigation
* Main page
* Contents
* Current events
* Random article
* About Wikipedia
* Contact us
* Donate
Contribute
* Help
* Learn to edit
* Community portal
* Recent changes
* Upload file
Search
Search
* Create account
* Log in
Personal tools
* Create account
* Log in
Pages for logged out editors learn more
* Contributions
* Talk
## Contents
move to sidebar hide
* (Top)
* 1 Training
* 2 History
* 3 Models
Toggle Models subsection
* 3.1 Artificial neurons
* 3.2 Organization
* 3.3 Hyperparameter
* 3.4 Learning
* 3.4.1 Learning rate
* 3.4.2 Cost function
* 3.4.3 Backpropagation
* 3.5 Learning paradigms
* 3.5.1 Supervised learning
* 3.5.2 Unsupervised learning
* 3.5.3 Reinforcement learning
* 3.5.4 Self-learning
* 3.5.5 Neuroevolution
* 3.6 Stochastic neural network
* 3.7 Other
* 3.7.1 Modes
* 4 Types
* 5 Network design
* 6 Applications
* 7 Theoretical properties
Toggle Theoretical properties subsection
* 7.1 Computational power
* 7.2 Capacity
* 7.3 Convergence
* 7.4 Generalization and statistics
* 8 Criticism
Toggle Criticism subsection
* 8.1 Training
* 8.2 Theory
* 8.3 Hardware
* 8.4 Practical counterexamples
* 8.5 Hybrid approaches
* 8.6 Dataset bias
* 9 Gallery
* 10 Recent advancements and future directions
Toggle Recent advancements and future directions subsection
* 10.1 Image processing
* 10.2 Speech recognition
* 10.3 Natural language processing
* 10.4 Control systems
* 10.5 Finance
* 10.6 Medicine
* 10.7 Content creation
* 11 See also
* 12 External links
* 13 Notes
* 14 References
* 15 Bibliography
Toggle the table of contents
# Neural network (machine learning)
64 languages
* العربية
* Արեւմտահայերէն
* Azərbaycanca
* বাংলা
* 閩南語 / Bân-lâm-gú
* Български
* Bosanski
* Català
* Čeština
* Dansk
* Deutsch
* Eesti
* Ελληνικά
* Español
* Esperanto
* Euskara
* فارسی
* Français
* Gaeilge
* Galego
* 한국어
* Հայերեն
* हिन्दी
* Hrvatski
* Bahasa Indonesia
* Interlingua
* Íslenska
* Italiano
* עברית
* ქართული
* Latina
* Latviešu
* Lietuvių
* Magyar
* Македонски
* Malagasy
* മലയാളം
* Bahasa Melayu
* Nederlands
* 日本語
* Norsk bokmål
* Norsk nynorsk
* ଓଡ଼ିଆ
* Oʻzbekcha / ўзбекча
* Polski
* Português
* Română
* Runa Simi
* Русский
* Simple English
* Slovenčina
* Ślůnski
* Српски / srpski
* Suomi
* Svenska
* தமிழ்
* ไทย
* Türkçe
* Українська
* اردو
* Tiếng Việt
* 吴语
* 粵語
* 中文
Edit links
* Article
* Talk
English
* Read
* Edit
* View history
Tools
Tools
move to sidebar hide
Actions
* Read
* Edit
* View history
General
* What links here
* Related changes
* Upload file
* Special pages
* Permanent link
* Page information
* Cite this page
* Get shortened URL
* Download QR code
* Wikidata item
Print/export
* Download as PDF
* Printable version
In other projects
* Wikimedia Commons
* Wikibooks
* Wikiversity
From Wikipedia, the free encyclopedia
Computational model used in machine learning, based on connected, hierarchical
functions
This article is about the computational models used for artificial
intelligence. For other uses, see Neural network (disambiguation) .
An artificial neural network is an interconnected group of nodes, inspired by
a simplification of neurons in a brain . Here, each circular node
represents an artificial neuron and an arrow represents a connection from
the output of one artificial neuron to the input of another. Part of a series
on
---
Machine learning
and data mining
Paradigms
* Supervised learning
* Unsupervised learning
* Online learning
* Batch learning
* Meta-learning
* Semi-supervised learning
* Self-supervised learning
* Reinforcement learning
* Curriculum learning
* Rule-based learning
* Quantum machine learning
Problems
* Classification
* Generative modeling
* Regression
* Clustering
* Dimensionality reduction
* Density estimation
* Anomaly detection
* Data cleaning
* AutoML
* Association rules
* Semantic analysis
* Structured prediction
* Feature engineering
* Feature learning
* Learning to rank
* Grammar induction
* Ontology learning
* Multimodal learning
Supervised learning
( classification • regression )
* Apprenticeship learning
* Decision trees
* Ensembles
* Bagging
* Boosting
* Random forest
* k -NN
* Linear regression
* Naive Bayes
* Artificial neural networks
* Logistic regression
* Perceptron
* Relevance vector machine (RVM)
* Support vector machine (SVM)
Clustering
* BIRCH
* CURE
* Hierarchical
* k -means
* Fuzzy
* Expectation–maximization (EM)
*
DBSCAN
* OPTICS
* Mean shift
Dimensionality reduction
* Factor analysis
* CCA
* ICA
* LDA
* NMF
* PCA
* PGD
* t-SNE
* SDL
Structured prediction
* Graphical models
* Bayes net
* Conditional random field
* Hidden Markov
Anomaly detection
* RANSAC
* k -NN
* Local outlier factor
* Isolation forest
Artificial neural network
* Autoencoder
* Cognitive computing
* Deep learning
* DeepDream
* Feedforward neural network
* Recurrent neural network
* LSTM
* GRU
* ESN
* reservoir computing
* Restricted Boltzmann machine
* GAN
* Diffusion model
* SOM
* Convolutional neural network
* U-Net
* Transformer
* Vision
* Mamba
* Spiking neural network
* Memtransistor
* Electrochemical RAM (ECRAM)
Reinforcement learning
* Q-learning
* SARSA
* Temporal difference (TD)
* Multi-agent
* Self-play
Learning with humans
* Active learning
* Crowdsourcing
* Human-in-the-loop
* RLHF
Model diagnostics
* Coefficient of determination
* Confusion matrix
* Learning curve
* ROC curve
Mathematical foundations
* Kernel machines
* Bias–variance tradeoff
* Computational learning theory
* Empirical risk minimization
* Occam learning
* PAC learning
* Statistical learning
* VC theory
Machine-learning venues
* ECML PKDD
* NeurIPS
* ICML
* ICLR
* IJCAI
* ML
* JMLR
Related articles
* Glossary of artificial intelligence
* List of datasets for machine-learning research
* List of datasets in computer vision and image processing
* Outline of machine learning
* v
* t
* e
In machine learning , a neural network (also artificial neural network
or neural net , abbreviated ANN or NN ) is a model inspired by the
structure and function of biological neural networks in animal brains .
[1] [2]
An ANN consists of connected units or nodes called artificial neurons ,
which loosely model the neurons in a brain. These are connected by edges ,
which model the synapses in a brain. Each artificial neuron receives signals
from connected neurons, then processes them and sends a signal to other
connected neurons. The "signal" is a real number , and the output of each
neuron is computed by some non-linear function of the sum of its inputs,
called the activation function . The strength of the signal at each
connection is determined by a weight , which adjusts during the learning
process.
Typically, neurons are aggregated into layers. Different layers may perform
different transformations on their inputs. Signals travel from the first layer
(the input layer ) to the last layer (the output layer ), possibly passing
through multiple intermediate layers ( hidden layers ). A network is
typically called a deep neural network if it has at least 2 hidden layers.
[3]
Artificial neural networks are used for various tasks, including predictive
modeling , adaptive control , and solving problems in artificial
intelligence . They can learn from experience, and can derive conclusions
from a complex and seemingly unrelated set of information.
## Training [ edit ]
Neural networks are typically trained through empirical risk minimization .
This method is based on the idea of optimizing the network's parameters to
minimize the difference, or empirical risk, between the predicted output and
the actual target values in a given dataset. [4] Gradient based methods such
as backpropagation are usually used to estimate the parameters of the
network. [4] During the training phase, ANNs learn from labeled training
data by iteratively updating their parameters to minimize a defined loss
function . [5] This method allows the network to generalize to unseen data.
Simplified example of training a neural network in object detection: The
network is trained by multiple images that are known to depict starfish and
sea urchins , which are correlated with "nodes" that represent visual
features . The starfish match with a ringed texture and a star outline,
whereas most sea urchins match with a striped texture and oval shape. However,
the instance of a ring textured sea urchin creates a weakly weighted
association between them.
Subsequent run of the network on an input image (left): [6] The network
correctly detects the starfish. However, the weakly weighted association
between ringed texture and sea urchin also confers a weak signal to the latter
from one of two intermediate nodes. In addition, a shell that was not included
in the training gives a weak signal for the oval shape, also resulting in a
weak signal for the sea urchin output. These weak signals may result in a
false positive result for sea urchin.
In reality, textures and outlines would not be represented by single nodes,
but rather by associated weight patterns of multiple nodes.
## History [ edit ]
Main article: History of artificial neural networks
Historically, digital computers evolved from the von Neumann model , and
operate via the execution of explicit instructions via access to memory by a
number of processors. Neural networks, on the other hand, originated from
efforts to model information processing in biological systems through the
framework of connectionism . Unlike the von Neumann model, connectionist
computing does not separate memory and processing.
The simplest kind of feedforward neural network (FNN) is a linear network,
which consists of a single layer of output nodes; the inputs are fed directly
to the outputs via a series of weights. The sum of the products of the weights
and the inputs is calculated at each node. The mean squared errors between
these calculated outputs and the given target values are minimized by creating
an adjustment to the weights. This technique has been known for over two
centuries as the method of least squares or linear regression . It was
used as a means of finding a good rough linear fit to a set of points by
Legendre (1805) and Gauss (1795) for the prediction of planetary movement.
[7] [8] [9] [10] [11]
Warren McCulloch and Walter Pitts [12] (1943) also considered a non-
learning computational model for neural networks. [13]
In the late 1940s, D. O. Hebb [14] created a learning hypothesis based on
the mechanism of neural plasticity that became known as Hebbian learning .
Hebbian learning is considered to be a 'typical' unsupervised learning rule
and its later variants were early models for long term potentiation . These
ideas started being applied to computational models in 1948 with Turing's "
unorganized machines ". Farley and Wesley A. Clark [15] were the first to
simulate a Hebbian network in 1954 at MIT. They used computational machines,
then called "calculators". Other neural network computational machines were
created by Rochester, Holland, Habit, and Duda [16] in 1956. In 1958,
psychologist Frank Rosenblatt invented the perceptron , the first
implemented artificial neural network, [17] [18] [19] [20] funded by the
United States Office of Naval Research . [21]
The invention of the perceptron raised public excitement for research in
Artificial Neural Networks, causing the US government to drastically increase
funding into deep learning research. This led to "the golden age of AI" fueled
by the optimistic claims made by computer scientists regarding the ability of
perceptrons to emulate human intelligence. [22] For example, in 1957 Herbert
Simon famously said: [22]
> It is not my aim to surprise or shock you—but the simplest way I can
> summarize is to say that there are now in the world machines that think,
> that learn and that create. Moreover, their ability to do these things is
> going to increase rapidly until—in a visible future—the range of problems
> they can handle will be coextensive with the range to which the human mind
> has been applied.
However, this wasn't the case as research stagnated in the United States
following the work of Minsky and Papert (1969), [23] who discovered that
basic perceptrons were incapable of processing the exclusive-or circuit and
that computers lacked sufficient power to train useful neural networks. This,
along with other factors such as the 1973 Lighthill report by James
Lighthill stating that research in Artificial Intelligence has not "produced
the major impact that was then promised," shutting funding in research into
the field of AI in all but two universities in the UK and in many major
institutions across the world. [24] This ushered an era called the AI
Winter with reduced research into connectionism due to a decrease in
government funding and an increased stress on symbolic artificial
intelligence in the United States and other Western countries. [25] [24]
During the AI Winter era, however, research outside the United States
continued, especially in Eastern Europe. By the time Minsky and Papert's book
on Perceptrons came out, methods for training multilayer perceptrons
(MLPs) were already known. The first deep learning MLP was published by
Alexey Grigorevich Ivakhnenko and Valentin Lapa in 1965, as the Group Method
of Data Handling . [26] [27] [28] The first deep learning MLP trained by
stochastic gradient descent [29] was published in 1967 by Shun'ichi Amari.
[30] [31] In computer experiments conducted by Amari's student Saito, a five
layer MLP with two modifiable layers learned useful internal representations
to classify non-linearily separable pattern classes. [31]
Self-organizing maps (SOMs) were described by Teuvo Kohonen in 1982. [32]
[33] SOMs are neurophysiologically inspired [34] neural networks that learn
low-dimensional representations of high-dimensional data while preserving the
topological structure of the data. They are trained using competitive
learning . [32]
The convolutional neural network (CNN) architecture with convolutional
layers and downsampling layers was introduced by Kunihiko Fukushima in 1980.
[35] He called it the neocognitron . In 1969, he also introduced the ReLU
(rectified linear unit) activation function . [36] [10] The rectifier has
become the most popular activation function for CNNs and deep neural networks
in general. [37] CNNs have become an essential tool for computer vision .
A key in later advances in artificial neural network research was the
backpropagation algorithm, an efficient application of the Leibniz chain
rule (1673) [38] to networks of differentiable nodes. [10] It is also
known as the reverse mode of automatic differentiation or reverse
accumulation , due to Seppo Linnainmaa (1970). [39] [40] [41] [42]
[10] The term "back-propagating errors" was introduced in 1962 by Frank
Rosenblatt, [43] [10] but he did not have an implementation of this
procedure, although Henry J. Kelley [44] and Bryson [45] had dynamic
programming based continuous precursors of backpropagation [26] [46] [47]
[48] already in 1960–61 in the context of control theory . [10] In 1973,
Dreyfus used backpropagation to adapt parameters of controllers in
proportion to error gradients. [49] In 1982, Paul Werbos applied
backpropagation to MLPs in the way that has become standard. [50] [46] In
1986 Rumelhart , Hinton and Williams showed that backpropagation learned
interesting internal representations of words as feature vectors when trained
to predict the next word in a sequence. [51]
In the late 1970s to early 1980s, interest briefly emerged in theoretically
investigating the Ising model created by Wilhelm Lenz (1920) and Ernst
Ising (1925) [52] in relation to Cayley tree topologies and large neural
networks . The Ising model is essentially a non-learning artificial
recurrent neural network (RNN) consisting of neuron-like threshold elements.
[10] In 1972, Shun'ichi Amari described an adaptive version of this
architecture, [53] [10] In 1981, the Ising model was solved exactly by
Peter Barth for the general case of closed Cayley trees (with loops) with an
arbitrary branching ratio [54] and found to exhibit unusual phase
transition behavior in its local-apex and long-range site-site correlations.
[55] [56] John Hopfield popularised this architecture in 1982, [57] and
it is now known as a Hopfield network .
The time delay neural network (TDNN) of Alex Waibel (1987) combined
convolutions and weight sharing and backpropagation. [58] [59] In 1988, Wei
Zhang et al. applied backpropagation to a CNN (a simplified Neocognitron with
convolutional interconnections between the image feature layers and the last
fully connected layer) for alphabet recognition. [60] [61] In 1989, Yann
LeCun et al. trained a CNN to recognize handwritten ZIP codes on mail.
[62] In 1992, max-pooling for CNNs was introduced by Juan Weng et al. to
help with least-shift invariance and tolerance to deformation to aid 3D
object recognition . [63] [64] [65] LeNet-5 (1998), a 7-level CNN by
Yann LeCun et al., [66] that classifies digits, was applied by several
banks to recognize hand-written numbers on checks digitized in 32x32 pixel
images.
From 1988 onward, [67] [68] the use of neural networks transformed the
field of protein structure prediction , in particular when the first
cascading networks were trained on profiles (matrices) produced by multiple
sequence alignments . [69]
In 1991, Sepp Hochreiter 's diploma thesis [70] identified and analyzed
the vanishing gradient problem [70] [71] and proposed recurrent residual
connections to solve it. His thesis was called "one of the most important
documents in the history of machine learning" by his supervisor Juergen
Schmidhuber . [10]
In 1991, Juergen Schmidhuber published adversarial neural networks that
contest with each other in the form of a zero-sum game , where one network's
gain is the other network's loss. [72] [73] [74] The first network is a
generative model that models a probability distribution over output
patterns. The second network learns by gradient descent to predict the
reactions of the environment to these patterns. This was called "artificial
curiosity."
In 1992, Juergen Schmidhuber proposed a hierarchy of RNNs pre-trained one
level at a time by self-supervised learning . [75] It uses predictive
coding to learn internal representations at multiple self-organizing time
scales. This can substantially facilitate downstream deep learning. The RNN
hierarchy can be collapsed into a single RNN, by distilling a higher level
chunker network into a lower level automatizer network. [75] [10] In the
same year he also published an alternative to RNNs [76] which is a
precursor of a linear Transformer . [77] [78] [10] It introduces the
concept internal spotlights of attention : [79] a slow feedforward neural
network learns by gradient descent to control the fast weights of another
neural network through outer products of self-generated activation patterns.
The development of metal–oxide–semiconductor (MOS) very-large-scale
integration (VLSI), in the form of complementary MOS (CMOS) technology,
enabled increasing MOS transistor counts in digital electronics . This
provided more processing power for the development of practical artificial
neural networks in the 1980s. [80]
Neural networks' early successes included in 1995 a (mostly) self-driving car.
[a] [81]
1997, Sepp Hochreiter and Juergen Schmidhuber introduced the deep learning
method called long short-term memory (LSTM), published in Neural
Computation. [82] LSTM recurrent neural networks can learn "very deep
learning" tasks [83] with long credit assignment paths that require memories
of events that happened thousands of discrete time steps before. The "vanilla
LSTM" with forget gate was introduced in 1999 by Felix Gers , Schmidhuber
and Fred Cummins. [84]
Geoffrey Hinton et al. (2006) proposed learning a high-level representation
using successive layers of binary or real-valued latent variables with a
restricted Boltzmann machine [85] to model each layer. In 2012, Ng and
Dean created a network that learned to recognize higher-level concepts, such
as cats, only from watching unlabeled images. [86] Unsupervised pre-training
and increased computing power from GPUs and distributed computing allowed
the use of larger networks, particularly in image and visual recognition
problems, which became known as "deep learning". [5]
Variants of the back-propagation algorithm, as well as unsupervised methods
by Geoff Hinton and colleagues at the University of Toronto , can be used
to train deep, highly nonlinear neural architectures, [87] similar to the
1980 Neocognitron by Kunihiko Fukushima , [88] and the "standard
architecture of vision", [89] inspired by the simple and complex cells
identified by David H. Hubel and Torsten Wiesel in the primary visual
cortex .
Computational devices have been created in CMOS for both biophysical
simulation and neuromorphic computing . More recent efforts show promise for
creating nanodevices for very large scale principal components analyses
and convolution . [90] If successful, these efforts could usher in a new
era of neural computing that is a step beyond digital computing, [91]
because it depends on learning rather than programming and because it is
fundamentally analog rather than digital even though the first
instantiations may in fact be with CMOS digital devices.
Ciresan and colleagues (2010) [92] showed that despite the vanishing
gradient problem , GPUs make backpropagation feasible for many-layered
feedforward neural networks. [93] Between 2009 and 2012, ANNs began winning
prizes in image recognition contests, approaching human level performance on
various tasks, initially in pattern recognition and handwriting recognition
. [94] [95] For example, the bi-directional and multi-dimensional long
short-term memory (LSTM) [96] [97] of Graves et al. won three
competitions in connected handwriting recognition in 2009 without any prior
knowledge about the three languages to be learned. [96] [97]
Ciresan and colleagues built the first pattern recognizers to achieve human-
competitive/superhuman performance [98] on benchmarks such as traffic sign
recognition (IJCNN 2012).
Radial basis function and wavelet networks were introduced in 2013. These can
be shown to offer best approximation properties and have been applied in
nonlinear system identification and classification applications. [99]
In 2014, the adversarial network principle was used in a generative
adversarial network (GAN) by Ian Goodfellow et al. [100] Here the
adversarial network (discriminator) outputs a value between 1 and 0 depending
on the likelihood of the first network's (generator) output is in a given set.
This can be used to create realistic deepfakes . [101] Excellent image
quality is achieved by Nvidia 's StyleGAN (2018) [102] based on the
Progressive GAN by Tero Karras, Timo Aila, Samuli Laine, and Jaakko Lehtinen.
[103] Here the GAN generator is grown from small to large scale in a
pyramidal fashion.
In 2015, Rupesh Kumar Srivastava, Klaus Greff, and Schmidhuber used the LSTM
principle to create the Highway network , a feedforward neural network with
hundreds of layers, much deeper than previous networks. [104] [105] 7
months later, Kaiming He, Xiangyu Zhang; Shaoqing Ren, and Jian Sun won the
ImageNet 2015 competition with an open-gated or gateless Highway network
variant called Residual neural network . [106]
In 2017, Ashish Vaswani et al. introduced the modern Transformer architecture
in their paper "Attention Is All You Need." [107] It combines this with a
softmax operator and a projection matrix. [10] Transformers have
increasingly become the model of choice for natural language processing .
[108] Many modern large language models such as ChatGPT , GPT-4 , and
BERT use it. Transformers are also increasingly being used in computer
vision . [109]
Ramenzanpour et al. showed in 2020 that analytical and computational
techniques derived from statistical physics of disordered systems can be
extended to large-scale problems, including machine learning, e.g., to analyze
the weight space of deep neural networks. [110]
## Models [ edit ]
| This section may be confusing or unclear to readers . Please help
clarify the section . There might be a discussion about this on the talk
page . ( April 2017 ) ( Learn how and when to remove this message )
---|---
Further information: Mathematics of artificial neural networks
Neuron and myelinated axon, with signal flow from inputs at dendrites to
outputs at axon terminals
ANNs began as an attempt to exploit the architecture of the human brain to
perform tasks that conventional algorithms had little success with. They soon
reoriented towards improving empirical results, abandoning attempts to remain
true to their biological precursors. ANNs have the ability to learn and model
non-linearities and complex relationships. This is achieved by neurons being
connected in various patterns, allowing the output of some neurons to become
the input of others. The network forms a directed , weighted graph .
[111]
An artificial neural network consists of simulated neurons. Each neuron is
connected to other nodes via links like a biological axon-synapse-dendrite
connection. All the nodes connected by links take in some data and use it to
perform specific operations and tasks on the data. Each link has a weight,
determining the strength of one node's influence on another, [112] allowing
weights to choose the signal between neurons.
### Artificial neurons [ edit ]
ANNs are composed of artificial neurons which are conceptually derived from
biological neurons . Each artificial neuron has inputs and produces a single
output which can be sent to multiple other neurons. [113] The inputs can be
the feature values of a sample of external data, such as images or documents,
or they can be the outputs of other neurons. The outputs of the final output
neurons of the neural net accomplish the task, such as recognizing an object
in an image.
To find the output of the neuron we take the weighted sum of all the inputs,
weighted by the weights of the connections from the inputs to the neuron.
We add a bias term to this sum. [114] This weighted sum is sometimes
called the activation . This weighted sum is then passed through a (usually
nonlinear) activation function to produce the output. The initial inputs are
external data, such as images and documents. The ultimate outputs accomplish
the task, such as recognizing an object in an image. [115]
### Organization [ edit ]
The neurons are typically organized into multiple layers, especially in deep
learning . Neurons of one layer connect only to neurons of the immediately
preceding and immediately following layers. The layer that receives external
data is the input layer . The layer that produces the ultimate result is the
output layer . In between them are zero or more hidden layers . Single
layer and unlayered networks are also used. Between two layers, multiple
connection patterns are possible. They can be 'fully connected', with every
neuron in one layer connecting to every neuron in the next layer. They can be
pooling , where a group of neurons in one layer connects to a single neuron
in the next layer, thereby reducing the number of neurons in that layer.
[116] Neurons with only such connections form a directed acyclic graph and
are known as feedforward networks . [117] Alternatively, networks that
allow connections between neurons in the same or previous layers are known as
recurrent networks . [118]
### Hyperparameter [ edit ]
Main article: Hyperparameter (machine learning)
A hyperparameter is a constant parameter whose value is set before the
learning process begins. The values of parameters are derived via learning.
Examples of hyperparameters include learning rate , the number of hidden
layers and batch size. [119] The values of some hyperparameters can be
dependent on those of other hyperparameters. For example, the size of some
layers can depend on the overall number of layers.
### Learning [ edit ]
| This section includes a list of references , related reading , or
external links , but its sources remain unclear because it lacks inline
citations . Please help improve this section by introducing more precise
citations. ( August 2019 ) ( Learn how and when to remove this message )
---|---
See also: Mathematical optimization , Estimation theory , and Machine
learning
Learning is the adaptation of the network to better handle a task by
considering sample observations. Learning involves adjusting the weights (and
optional thresholds) of the network to improve the accuracy of the result.
This is done by minimizing the observed errors. Learning is complete when
examining additional observations does not usefully reduce the error rate.
Even after learning, the error rate typically does not reach 0. If after
learning, the error rate is too high, the network typically must be
redesigned. Practically this is done by defining a cost function that is
evaluated periodically during learning. As long as its output continues to
decline, learning continues. The cost is frequently defined as a statistic
whose value can only be approximated. The outputs are actually numbers, so
when the error is low, the difference between the output (almost certainly a
cat) and the correct answer (cat) is small. Learning attempts to reduce the
total of the differences across the observations. Most learning models can be
viewed as a straightforward application of optimization theory and
statistical estimation . [111] [120]
#### Learning rate [ edit ]
Main article: Learning rate
The learning rate defines the size of the corrective steps that the model
takes to adjust for errors in each observation. [121] A high learning rate
shortens the training time, but with lower ultimate accuracy, while a lower
learning rate takes longer, but with the potential for greater accuracy.
Optimizations such as Quickprop are primarily aimed at speeding up error
minimization, while other improvements mainly try to increase reliability. In
order to avoid oscillation inside the network such as alternating connection
weights, and to improve the rate of convergence, refinements use an adaptive
learning rate that increases or decreases as appropriate. [122] The concept
of momentum allows the balance between the gradient and the previous change to
be weighted such that the weight adjustment depends to some degree on the
previous change. A momentum close to 0 emphasizes the gradient, while a value
close to 1 emphasizes the last change.
#### Cost function [ edit ]
While it is possible to define a cost function ad hoc , frequently the
choice is determined by the function's desirable properties (such as
convexity ) or because it arises from the model (e.g. in a probabilistic
model the model's posterior probability can be used as an inverse cost).
#### Backpropagation [ edit ]
Main article: Backpropagation
Backpropagation is a method used to adjust the connection weights to
compensate for each error found during learning. The error amount is
effectively divided among the connections. Technically, backprop calculates
the gradient (the derivative) of the cost function associated with a given
state with respect to the weights. The weight updates can be done via
stochastic gradient descent or other methods, such as extreme learning
machines , [123] "no-prop" networks, [124] training without backtracking,
[125] "weightless" networks, [126] [127] and non-connectionist neural
networks . [ citation needed ]
### Learning paradigms [ edit ]
| This section includes a list of references , related reading , or
external links , but its sources remain unclear because it lacks inline
citations . Please help improve this section by introducing more precise
citations. ( August 2019 ) ( Learn how and when to remove this message )
---|---
Machine learning is commonly separated into three main learning paradigms,
supervised learning , [128] unsupervised learning [129] and
reinforcement learning . [130] Each corresponds to a particular learning
task.
#### Supervised learning [ edit ]
Supervised learning uses a set of paired inputs and desired outputs. The
learning task is to produce the desired output for each input. In this case,
the cost function is related to eliminating incorrect deductions. [131] A
commonly used cost is the mean-squared error , which tries to minimize the
average squared error between the network's output and the desired output.
Tasks suited for supervised learning are pattern recognition (also known as
classification) and regression (also known as function approximation).
Supervised learning is also applicable to sequential data (e.g., for
handwriting, speech and gesture recognition ). This can be thought of as
learning with a "teacher", in the form of a function that provides continuous
feedback on the quality of solutions obtained thus far.
#### Unsupervised learning [ edit ]
In unsupervised learning , input data is given along with the cost function,
some function of the data x {\displaystyle \textstyle x} and the network's
output. The cost function is dependent on the task (the model domain) and any
a priori assumptions (the implicit properties of the model, its parameters
and the observed variables). As a trivial example, consider the model f ( x
) = a {\displaystyle \textstyle f(x)=a} where a {\displaystyle
\textstyle a} is a constant and the cost C = E [ ( x − f ( x ) )
2 ] {\displaystyle \textstyle C=E[(x-f(x))^{2}]} . Minimizing this cost
produces a value of a {\displaystyle \textstyle a} that is equal to the
mean of the data. The cost function can be much more complicated. Its form
depends on the application: for example, in compression it could be related
to the mutual information between x {\displaystyle \textstyle x} and f
( x ) {\displaystyle \textstyle f(x)} , whereas in statistical modeling,
it could be related to the posterior probability of the model given the data
(note that in both of those examples, those quantities would be maximized
rather than minimized). Tasks that fall within the paradigm of unsupervised
learning are in general estimation problems; the applications include
clustering , the estimation of statistical distributions , compression
and filtering .
#### Reinforcement learning [ edit ]
Main article: Reinforcement learning
See also: Stochastic control
In applications such as playing video games, an actor takes a string of
actions, receiving a generally unpredictable response from the environment
after each one. The goal is to win the game, i.e., generate the most positive
(lowest cost) responses. In reinforcement learning , the aim is to weight
the network (devise a policy) to perform actions that minimize long-term
(expected cumulative) cost. At each point in time the agent performs an action
and the environment generates an observation and an instantaneous cost,
according to some (usually unknown) rules. The rules and the long-term cost
usually only can be estimated. At any juncture, the agent decides whether to
explore new actions to uncover their costs or to exploit prior learning to
proceed more quickly.
Formally the environment is modeled as a Markov decision process (MDP) with states s 1 , . . . , s n ∈ S {\displaystyle \textstyle {s_{1},...,s_{n}}\in S} and actions a 1 , . . . , a m ∈ A {\displaystyle \textstyle {a_{1},...,a_{m}}\in A} . Because the state transitions are not known, probability distributions are used instead: the instantaneous cost distribution P ( c t | s t ) {\displaystyle \textstyle P(c_{t}|s_{t})} , the observation distribution P ( x t | s t ) {\displaystyle \textstyle P(x_{t}|s_{t})} and the transition distribution P ( s t \+ 1 | s t , a t ) {\displaystyle \textstyle P(s_{t+1}|s_{t},a_{t})} , while a policy is defined as the conditional distribution over actions given the observations. Taken together, the two define a Markov chain (MC). The aim is to discover the lowest-cost MC.
ANNs serve as the learning component in such applications. [132] [133]
Dynamic programming coupled with ANNs (giving neurodynamic programming)
[134] has been applied to problems such as those involved in vehicle routing
, [135] video games, natural resource management [136] [137] and
medicine [138] because of ANNs ability to mitigate losses of accuracy even
when reducing the discretization grid density for numerically approximating
the solution of control problems. Tasks that fall within the paradigm of
reinforcement learning are control problems, games and other sequential
decision making tasks.
#### Self-learning [ edit ]
Self-learning in neural networks was introduced in 1982 along with a neural
network capable of self-learning named crossbar adaptive array (CAA). [139]
It is a system with only one input, situation s, and only one output, action
(or behavior) a. It has neither external advice input nor external
reinforcement input from the environment. The CAA computes, in a crossbar
fashion, both decisions about actions and emotions (feelings) about
encountered situations. The system is driven by the interaction between
cognition and emotion. [140] Given the memory matrix, W =||w(a,s)||, the
crossbar self-learning algorithm in each iteration performs the following
computation:
In situation s perform action a;
Receive consequence situation s';
Compute emotion of being in consequence situation v(s');
Update crossbar memory w'(a,s) = w(a,s) + v(s').
The backpropagated value (secondary reinforcement) is the emotion toward the
consequence situation. The CAA exists in two environments, one is behavioral
environment where it behaves, and the other is genetic environment, where from
it initially and only once receives initial emotions about to be encountered
situations in the behavioral environment. Having received the genome vector
(species vector) from the genetic environment, the CAA will learn a goal-
seeking behavior, in the behavioral environment that contains both desirable
and undesirable situations. [141]
#### Neuroevolution [ edit ]
Main article: Neuroevolution
Neuroevolution can create neural network topologies and weights using
evolutionary computation . It is competitive with sophisticated gradient
descent approaches [ citation needed ] . One advantage of neuroevolution
is that it may be less prone to get caught in "dead ends". [142]
### Stochastic neural network [ edit ]
Stochastic neural networks originating from Sherrington–Kirkpatrick models
are a type of artificial neural network built by introducing random variations
into the network, either by giving the network's artificial neurons
stochastic transfer functions, or by giving them stochastic weights. This
makes them useful tools for optimization problems, since the random
fluctuations help the network escape from local minima . [143] Stochastic
neural networks trained using a Bayesian approach are known as Bayesian
neural networks . [144]
### Other [ edit ]
In a Bayesian framework, a distribution over the set of allowed models is
chosen to minimize the cost. Evolutionary methods , [145] gene expression
programming , [146] simulated annealing , [147] expectation-maximization
, non-parametric methods and particle swarm optimization [148] are other
learning algorithms. Convergent recursion is a learning algorithm for
cerebellar model articulation controller (CMAC) neural networks. [149]
[150]
#### Modes [ edit ]
| This section includes a list of references , related reading , or
external links , but its sources remain unclear because it lacks inline
citations . Please help improve this section by introducing more precise
citations. ( August 2019 ) ( Learn how and when to remove this message )
---|---
Two modes of learning are available: stochastic and batch. In stochastic
learning, each input creates a weight adjustment. In batch learning weights
are adjusted based on a batch of inputs, accumulating errors over the batch.
Stochastic learning introduces "noise" into the process, using the local
gradient calculated from one data point; this reduces the chance of the
network getting stuck in local minima. However, batch learning typically
yields a faster, more stable descent to a local minimum, since each update is
performed in the direction of the batch's average error. A common compromise
is to use "mini-batches", small batches with samples in each batch selected
stochastically from the entire data set.
## Types [ edit ]
Main article: Types of artificial neural networks
ANNs have evolved into a broad family of techniques that have advanced the
state of the art across multiple domains. The simplest types have one or more
static components, including number of units, number of layers, unit weights
and topology . Dynamic types allow one or more of these to evolve via
learning. The latter is much more complicated but can shorten learning periods
and produce better results. Some types allow/require learning to be
"supervised" by the operator, while others operate independently. Some types
operate purely in hardware, while others are purely software and run on
general purpose computers.
Some of the main breakthroughs include:
* Convolutional neural networks that have proven particularly successful in processing visual and other two-dimensional data; [151] [152] where long short-term memory avoids the vanishing gradient problem [153] and can handle signals that have a mix of low and high frequency components aiding large-vocabulary speech recognition, [154] [155] text-to-speech synthesis, [156] [46] [157] and photo-real talking heads; [158]
* Competitive networks such as generative adversarial networks in which multiple networks (of varying structure) compete with each other, on tasks such as winning a game [159] or on deceiving the opponent about the authenticity of an input. [100]
## Network design [ edit ]
Using artificial neural networks requires an understanding of their
characteristics.
* Choice of model: This depends on the data representation and the application. Model parameters include the number, type, and connectedness of network layers, as well as the size of each and the connection type (full, pooling, etc. ). Overly complex models learn slowly.
* Learning algorithm : Numerous trade-offs exist between learning algorithms. Almost any algorithm will work well with the correct hyperparameters [160] for training on a particular data set. However, selecting and tuning an algorithm for training on unseen data requires significant experimentation.
* Robustness : If the model, cost function and learning algorithm are selected appropriately, the resulting ANN can become robust.
Neural architecture search (NAS) uses machine learning to automate ANN
design. Various approaches to NAS have designed networks that compare well
with hand-designed systems. The basic search algorithm is to propose a
candidate model, evaluate it against a dataset, and use the results as
feedback to teach the NAS network. [161] Available systems include AutoML
and AutoKeras. [162] scikit-learn library provides functions to help with
building a deep network from scratch. We can then implement a deep network
with TensorFlow or Keras .
Hyperparameters must also be defined as part of the design (they are not
learned), governing matters such as how many neurons are in each layer,
learning rate, step, stride, depth, receptive field and padding (for CNNs),
etc. [163]
The Python code snippet provides an overview of the training function, which
uses the training dataset, number of hidden layer units, learning rate, and
number of iterations as parameters:
def train(X, y, n_hidden, learning_rate, n_iter):
m, n_input = X.shape
# 1. random initialize weights and biases
w1 = np.random.randn(n_input, n_hidden)
b1 = np.zeros((1, n_hidden))
w2 = np.random.randn(n_hidden, 1)
b2 = np.zeros((1, 1))
# 2. in each iteration, feed all layers with the latest weights and biases
for i in range(n_iter + 1):
z2 = np.dot(X, w1) + b1
a2 = sigmoid(z2)
z3 = np.dot(a2, w2) + b2
a3 = z3
dz3 = a3 - y
dw2 = np.dot(a2.T, dz3)
db2 = np.sum(dz3, axis=0, keepdims=True)
dz2 = np.dot(dz3, w2.T) * sigmoid_derivative(z2)
dw1 = np.dot(X.T, dz2)
db1 = np.sum(dz2, axis=0)
# 3. update weights and biases with gradients
w1 -= learning_rate * dw1 / m
w2 -= learning_rate * dw2 / m
b1 -= learning_rate * db1 / m
b2 -= learning_rate * db2 / m
if i % 1000 == 0:
print("Epoch", i, "loss: ", np.mean(np.square(dz3)))
model = {"w1": w1, "b1": b1, "w2": w2, "b2": b2}
return model
[ citation needed ]
## Applications [ edit ]
Because of their ability to reproduce and model nonlinear processes,
artificial neural networks have found applications in many disciplines. These
include:
* Function approximation , [164] or regression analysis , [165] (including time series prediction , fitness approximation , [166] and modeling)
* Data processing [167] (including filtering, clustering, blind source separation , [168] and compression)
* Nonlinear system identification [99] and control (including vehicle control, trajectory prediction, [169] adaptive control , process control , and natural resource management )
* Pattern recognition (including radar systems, face identification , signal classification, [170] novelty detection , 3D reconstruction , [171] object recognition, and sequential decision making [172] )
* Sequence recognition (including gesture , speech , and handwritten and printed text recognition [173] )
* Sensor data analysis [174] (including image analysis )
* Robotics (including directing manipulators and prostheses )
* Data mining (including knowledge discovery in databases )
* Finance [175] (such as ex-ante models for specific financial long-run forecasts and artificial financial markets )
* Quantum chemistry [176]
* General game playing [177]
* Generative AI [178]
* Data visualization
* Machine translation
* Social network filtering [179]
* E-mail spam filtering
* Medical diagnosis
ANNs have been used to diagnose several types of cancers [180] [181] and to
distinguish highly invasive cancer cell lines from less invasive lines using
only cell shape information. [182] [183]
ANNs have been used to accelerate reliability analysis of infrastructures
subject to natural disasters [184] [185] and to predict foundation
settlements. [186] It can also be useful to mitigate flood by the use of
ANNs for modelling rainfall-runoff. [187] ANNs have also been used for
building black-box models in geoscience : hydrology , [188] [189] ocean
modelling and coastal engineering , [190] [191] and geomorphology .
[192] ANNs have been employed in cybersecurity , with the objective to
discriminate between legitimate activities and malicious ones. For example,
machine learning has been used for classifying Android malware, [193] for
identifying domains belonging to threat actors and for detecting URLs posing a
security risk. [194] Research is underway on ANN systems designed for
penetration testing, for detecting botnets, [195] credit cards frauds [196]
and network intrusions.
ANNs have been proposed as a tool to solve partial differential equations in
physics [197] [198] [199] and simulate the properties of many-body open
quantum systems . [200] [201] [202] [203] In brain research ANNs have
studied short-term behavior of individual neurons , [204] the dynamics of
neural circuitry arise from interactions between individual neurons and how
behavior can arise from abstract neural modules that represent complete
subsystems. Studies considered long-and short-term plasticity of neural
systems and their relation to learning and memory from the individual neuron
to the system level.
It is possible to create a profile of a user's interests from pictures, using
artificial neural networks trained for object recognition. [205]
Beyond their traditional applications, artificial neural networks are
increasingly being utilized in interdisciplinary research, such as materials
science. For instance, graph neural networks (GNNs) have demonstrated their
capability in scaling deep learning for the discovery of new stable materials
by efficiently predicting the total energy of crystals. This application
underscores the adaptability and potential of ANNs in tackling complex
problems beyond the realms of predictive modeling and artificial intelligence,
opening new pathways for scientific discovery and innovation. [206]
## Theoretical properties [ edit ]
### Computational power [ edit ]
The multilayer perceptron is a universal function approximator, as proven
by the universal approximation theorem . However, the proof is not
constructive regarding the number of neurons required, the network topology,
the weights and the learning parameters.
A specific recurrent architecture with rational -valued weights (as opposed
to full precision real number -valued weights) has the power of a universal
Turing machine , [207] using a finite number of neurons and standard linear
connections. Further, the use of irrational values for weights results in a
machine with super-Turing power. [208] [209] [ failed verification ]
### Capacity [ edit ]
A model's "capacity" property corresponds to its ability to model any given
function. It is related to the amount of information that can be stored in the
network and to the notion of complexity. Two notions of capacity are known by
the community. The information capacity and the VC Dimension. The information
capacity of a perceptron is intensively discussed in Sir David MacKay's book
[210] which summarizes work by Thomas Cover. [211] The capacity of a
network of standard neurons (not convolutional) can be derived by four rules
[212] that derive from understanding a neuron as an electrical element. The
information capacity captures the functions modelable by the network given any
data as input. The second notion, is the VC dimension . VC Dimension uses
the principles of measure theory and finds the maximum capacity under the
best possible circumstances. This is, given input data in a specific form. As
noted in, [210] the VC Dimension for arbitrary inputs is half the
information capacity of a Perceptron. The VC Dimension for arbitrary points is
sometimes referred to as Memory Capacity. [213]
### Convergence [ edit ]
Models may not consistently converge on a single solution, firstly because
local minima may exist, depending on the cost function and the model.
Secondly, the optimization method used might not guarantee to converge when it
begins far from any local minimum. Thirdly, for sufficiently large data or
parameters, some methods become impractical.
Another issue worthy to mention is that training may cross some Saddle point
which may lead the convergence to the wrong direction.
The convergence behavior of certain types of ANN architectures are more
understood than others. When the width of network approaches to infinity, the
ANN is well described by its first order Taylor expansion throughout training,
and so inherits the convergence behavior of affine models . [214] [215]
Another example is when parameters are small, it is observed that ANNs often
fits target functions from low to high frequencies. This behavior is referred
to as the spectral bias, or frequency principle, of neural networks. [216]
[217] [218] [219] This phenomenon is the opposite to the behavior of some
well studied iterative numerical schemes such as Jacobi method . Deeper
neural networks have been observed to be more biased towards low frequency
functions. [220]
### Generalization and statistics [ edit ]
| This section includes a list of references , related reading , or
external links , but its sources remain unclear because it lacks inline
citations . Please help improve this section by introducing more precise
citations. ( August 2019 ) ( Learn how and when to remove this message )
---|---
Applications whose goal is to create a system that generalizes well to unseen
examples, face the possibility of over-training. This arises in convoluted or
over-specified systems when the network capacity significantly exceeds the
needed free parameters. Two approaches address over-training. The first is to
use cross-validation and similar techniques to check for the presence of
over-training and to select hyperparameters to minimize the generalization
error.
The second is to use some form of regularization . This concept emerges in a
probabilistic (Bayesian) framework, where regularization can be performed by
selecting a larger prior probability over simpler models; but also in
statistical learning theory, where the goal is to minimize over two
quantities: the 'empirical risk' and the 'structural risk', which roughly
corresponds to the error over the training set and the predicted error in
unseen data due to overfitting.
Confidence analysis of a neural network
Supervised neural networks that use a mean squared error (MSE) cost function
can use formal statistical methods to determine the confidence of the trained
model. The MSE on a validation set can be used as an estimate for variance.
This value can then be used to calculate the confidence interval of network
output, assuming a normal distribution . A confidence analysis made this way
is statistically valid as long as the output probability distribution stays
the same and the network is not modified.
By assigning a softmax activation function , a generalization of the
logistic function , on the output layer of the neural network (or a softmax
component in a component-based network) for categorical target variables, the
outputs can be interpreted as posterior probabilities. This is useful in
classification as it gives a certainty measure on classifications.
The softmax activation function is:
y i = e x i ∑ j = 1 c e x j {\displaystyle y_{i}={\frac {e^{x_{i}}}{\sum _{j=1}^{c}e^{x_{j}}}}}
## Criticism [ edit ]
### Training [ edit ]
A common criticism of neural networks, particularly in robotics, is that they
require too many training samples for real-world operation. [221] Any
learning machine needs sufficient representative examples in order to capture
the underlying structure that allows it to generalize to new cases. Potential
solutions include randomly shuffling training examples, by using a numerical
optimization algorithm that does not take too large steps when changing the
network connections following an example, grouping examples in so-called mini-
batches and/or introducing a recursive least squares algorithm for CMAC .
[149] Dean Pomerleau uses a neural network to train a robotic vehicle to
drive on multiple types of roads (single lane, multi-lane, dirt, etc.), and a
large amount of his research is devoted to extrapolating multiple training
scenarios from a single training experience, and preserving past training
diversity so that the system does not become overtrained (if, for example, it
is presented with a series of right turns—it should not learn to always turn
right). [222]
### Theory [ edit ]
A central claim [ citation needed ] of ANNs is that they embody new and
powerful general principles for processing information. These principles are
ill-defined. It is often claimed [ by whom? ] that they are emergent
from the network itself. This allows simple statistical association (the basic
function of artificial neural networks) to be described as learning or
recognition. In 1997, Alexander Dewdney , a former Scientific American
columnist, commented that as a result, artificial neural networks have a
"something-for-nothing quality, one that imparts a peculiar aura of laziness
and a distinct lack of curiosity about just how good these computing systems
are. No human hand (or mind) intervenes; solutions are found as if by magic;
and no one, it seems, has learned anything". [223] One response to Dewdney
is that neural networks have been successfully used to handle many complex and
diverse tasks, ranging from autonomously flying aircraft [224] to detecting
credit card fraud to mastering the game of Go .
Technology writer Roger Bridgman commented:
> Neural networks, for instance, are in the dock not only because they have
> been hyped to high heaven, (what hasn't?) but also because you could create
> a successful net without understanding how it worked: the bunch of numbers
> that captures its behaviour would in all probability be "an opaque,
> unreadable table...valueless as a scientific resource".
>
> In spite of his emphatic declaration that science is not technology, Dewdney
> seems here to pillory neural nets as bad science when most of those devising
> them are just trying to be good engineers. An unreadable table that a useful
> machine could read would still be well worth having. [225]
Although it is true that analyzing what has been learned by an artificial
neural network is difficult, it is much easier to do so than to analyze what
has been learned by a biological neural network. Moreover, recent emphasis on
the explainability of AI has contributed towards the development of methods,
notably those based on attention mechanisms, for visualizing and explaining
learned neural networks. Furthermore, researchers involved in exploring
learning algorithms for neural networks are gradually uncovering generic
principles that allow a learning machine to be successful. For example, Bengio
and LeCun (2007) wrote an article regarding local vs non-local learning, as
well as shallow vs deep architecture. [226]
Biological brains use both shallow and deep circuits as reported by brain
anatomy, [227] displaying a wide variety of invariance. Weng [228] argued
that the brain self-wires largely according to signal statistics and
therefore, a serial cascade cannot catch all major statistical dependencies.
### Hardware [ edit ]
Large and effective neural networks require considerable computing resources.
[229] While the brain has hardware tailored to the task of processing signals
through a graph of neurons, simulating even a simplified neuron on von
Neumann architecture may consume vast amounts of memory and storage.
Furthermore, the designer often needs to transmit signals through many of
these connections and their associated neurons – which require enormous CPU
power and time.
Schmidhuber noted that the resurgence of neural networks in the twenty-first
century is largely attributable to advances in hardware: from 1991 to 2015,
computing power, especially as delivered by GPGPUs (on GPUs ), has
increased around a million-fold, making the standard backpropagation algorithm
feasible for training networks that are several layers deeper than before.
[26] The use of accelerators such as FPGAs and GPUs can reduce training
times from months to days. [229]
Neuromorphic engineering or a physical neural network addresses the
hardware difficulty directly, by constructing non-von-Neumann chips to
directly implement neural networks in circuitry. Another type of chip
optimized for neural network processing is called a Tensor Processing Unit ,
or TPU. [230]
### Practical counterexamples [ edit ]
Analyzing what has been learned by an ANN is much easier than analyzing what
has been learned by a biological neural network. Furthermore, researchers
involved in exploring learning algorithms for neural networks are gradually
uncovering general principles that allow a learning machine to be successful.
For example, local vs. non-local learning and shallow vs. deep architecture.
[231]
### Hybrid approaches [ edit ]
Advocates of hybrid models (combining neural networks and symbolic
approaches) say that such a mixture can better capture the mechanisms of the
human mind. [232] [233]
### Dataset bias [ edit ]
Neural networks are dependent on the quality of the data they are trained on,
thus low quality data with imbalanced representativeness can lead to the model
learning and perpetuating societal biases. [234] [235] These inherited
biases become especially critical when the ANNs are integrated into real-world
scenarios where the training data may be imbalanced due to the scarcity of
data for a specific race, gender or other attribute. [234] This imbalance
can result in the model having inadequate representation and understanding of
underrepresented groups, leading to discriminatory outcomes that exasperate
societal inequalities, especially in applications like facial recognition ,
hiring processes, and law enforcement . [235] [236] For example, in 2018,
Amazon had to scrap a recruiting tool because the model favored men over
women for jobs in software engineering due to the higher number of male
workers in the field. [236] The program would penalize any resume with the
word "woman" or the name of any women's college. However, the use of
synthetic data can help reduce dataset bias and increase representation in
datasets. [237]
## Gallery [ edit ]
* A single-layer feedforward artificial neural network. Arrows originating from x 2 {\displaystyle \scriptstyle x_{2}} are omitted for clarity. There are p inputs to this network and q outputs. In this system, the value of the qth output, y q {\displaystyle y_{q}} , is calculated as y q = K ∗ ( ∑ i ( x i ∗ w i q ) − b q ) . {\displaystyle \scriptstyle y_{q}=K*(\sum _{i}(x_{i}*w_{iq})-b_{q}).}
* A two-layer feedforward artificial neural network
* An artificial neural network
* An ANN dependency graph
* A single-layer feedforward artificial neural network with 4 inputs, 6 hidden nodes and 2 outputs. Given position state and direction, it outputs wheel based control values.
* A two-layer feedforward artificial neural network with 8 inputs, 2x8 hidden nodes and 2 outputs. Given position state, direction and other environment values, it outputs thruster based control values.
* Parallel pipeline structure of CMAC neural network. This learning algorithm can converge in one step.
## Recent advancements and future directions [ edit ]
Artificial neural networks (ANNs) have undergone significant advancements,
particularly in their ability to model complex systems, handle large data
sets, and adapt to various types of applications. Their evolution over the
past few decades has been marked by a broad range of applications in fields
such as image processing, speech recognition, natural language processing,
finance, and medicine.
### Image processing [ edit ]
In the realm of image processing, ANNs are employed in tasks such as image
classification, object recognition, and image segmentation. For instance, deep
convolutional neural networks (CNNs) have been important in handwritten digit
recognition, achieving state-of-the-art performance. [238] This demonstrates
the ability of ANNs to effectively process and interpret complex visual
information, leading to advancements in fields ranging from automated
surveillance to medical imaging. [238]
### Speech recognition [ edit ]
By modeling speech signals, ANNs are used for tasks like speaker
identification and speech-to-text conversion. Deep neural network
architectures have introduced significant improvements in large vocabulary
continuous speech recognition, outperforming traditional techniques. [238]
[239] These advancements have enabled the development of more accurate and
efficient voice-activated systems, enhancing user interfaces in technology
products.
### Natural language processing [ edit ]
In natural language processing, ANNs are used for tasks such as text
classification, sentiment analysis, and machine translation. They have enabled
the development of models that can accurately translate between languages,
understand the context and sentiment in textual data, and categorize text
based on content. [238] [239] This has implications for automated customer
service, content moderation, and language understanding technologies.
### Control systems [ edit ]
In the domain of control systems, ANNs are used to model dynamic systems for
tasks such as system identification, control design, and optimization. For
instance, deep feedforward neural networks are important in system
identification and control applications.
### Finance [ edit ]
Further information: Applications of artificial intelligence § Trading and
investment
ANNs are used for stock market prediction and credit scoring :
* In investing, ANNs can process vast amounts of financial data, recognize complex patterns, and forecast stock market trends, aiding investors and risk managers in making informed decisions. [238]
* In credit scoring, ANNs offer data-driven, personalized assessments of creditworthiness, improving the accuracy of default predictions and automating the lending process. [239]
ANNs require high-quality data and careful tuning, and their "black-box"
nature can pose challenges in interpretation. Nevertheless, ongoing
advancements suggest that ANNs continue to play a role in finance, offering
valuable insights and enhancing risk management strategies .
### Medicine [ edit ]
ANNs are able to process and analyze vast medical datasets. They enhance
diagnostic accuracy, especially by interpreting complex medical imaging for
early disease detection, and by predicting patient outcomes for personalized
treatment planning. [239] In drug discovery, ANNs speed up the
identification of potential drug candidates and predict their efficacy and
safety, significantly reducing development time and costs. [238]
Additionally, their application in personalized medicine and healthcare data
analysis allows tailored therapies and efficient patient care management.
[239] Ongoing research is aimed at addressing remaining challenges such as
data privacy and model interpretability, as well as expanding the scope of ANN
applications in medicine.
### Content creation [ edit ]
ANNs such as generative adversarial networks ( GAN ) and transformers are
used for content creation across numerous industries. [240] This is because
deep learning models are able to learn the style of an artist or musician from
huge datasets and generate completely new artworks and music compositions. For
instance, DALL-E is a deep neural network trained on 650 million pairs of
images and texts across the internet that can create artworks based on text
entered by the user. [241] In the field of music, transformers are used to
create original music for commercials and documentaries through companies such
as AIVA and Jukedeck . [242] In the marketing industry generative models
are used to create personalized advertisements for consumers. [240]
Additionally, major film companies are partnering with technology companies to
analyze the financial success of a film, such as the partnership between
Warner Bros and technology company Cinelytic established in 2020. [243]
Furthermore, neural networks have found uses in video game creation, where Non
Player Characters (NPCs) can make decisions based on all the characters
currently in the game. [244]
## See also [ edit ]
* ADALINE
* Autoencoder
* Bio-inspired computing
* Blue Brain Project
* Catastrophic interference
* Cognitive architecture
* Connectionist expert system
* Connectomics
* Deep image prior
* Digital morphogenesis
* Efficiently updatable neural network
* Evolutionary algorithm
* Genetic algorithm
* Hyperdimensional computing
* In situ adaptive tabulation
* Large width limits of neural networks
* List of machine learning concepts
* Memristor
* Neural gas
* Neural network software
* Optical neural network
* Parallel distributed processing
* Philosophy of artificial intelligence
* Predictive analytics
* Quantum neural network
* Support vector machine
* Spiking neural network
* Stochastic parrot
* Tensor product network
## External links [ edit ]
Listen to this article ( 31 minutes )
This audio file was created from a revision of this article dated 27 November
2011 ( 2011-11-27 ) , and does not reflect subsequent edits.
( Audio help · More spoken articles )
* A Brief Introduction to Neural Networks (D. Kriesel) \- Illustrated, bilingual manuscript about artificial neural networks; Topics so far: Perceptrons, Backpropagation, Radial Basis Functions, Recurrent Neural Networks, Self Organizing Maps, Hopfield Networks.
* Review of Neural Networks in Materials Science
* Artificial Neural Networks Tutorial in three languages (Univ. Politécnica de Madrid)
* Another introduction to ANN
* Next Generation of Neural Networks \- Google Tech Talks
* Performance of Neural Networks
* Neural Networks and Information
* Sanderson G (5 October 2017). "But what is a Neural Network?" . 3Blue1Brown . Archived from the original on 7 November 2021 – via YouTube .
## Notes [ edit ]
1. ^ Steering for the 1995 " No Hands Across America " required "only a few human assists".
## References [ edit ]
1. ^ Hardesty L (14 April 2017). "Explained: Neural networks" . MIT News Office . Retrieved 2 June 2022 .
2. ^ Yang Z, Yang Z (2014). Comprehensive Biomedical Physics . Karolinska Institute, Stockholm, Sweden: Elsevier. p. 1. ISBN 978-0-444-53633-4 . Archived from the original on 28 July 2022 . Retrieved 28 July 2022 .
3. ^ Bishop CM (17 August 2006). Pattern Recognition and Machine Learning . New York: Springer. ISBN 978-0-387-31073-2 .
4. ^ a b Vapnik VN, Vapnik VN (1998). The nature of statistical learning theory (Corrected 2nd print. ed.). New York Berlin Heidelberg: Springer. ISBN 978-0-387-94559-0 .
5. ^ a b Ian Goodfellow and Yoshua Bengio and Aaron Courville (2016). Deep Learning . MIT Press. Archived from the original on 16 April 2016 . Retrieved 1 June 2016 .
6. ^ Ferrie, C., Kaiser, S. (2019). Neural Networks for Babies . Sourcebooks. ISBN 978-1-4926-7120-6 .
7. ^ Mansfield Merriman, "A List of Writings Relating to the Method of Least Squares"
8. ^ Stigler SM (1981). "Gauss and the Invention of Least Squares" . Ann. Stat . 9 (3): 465–474. doi : 10.1214/aos/1176345451 .
9. ^ Bretscher O (1995). Linear Algebra With Applications (3rd ed.). Upper Saddle River, NJ: Prentice Hall.
10. ^ a b c d e f g h i j k l Schmidhuber J (2022). "Annotated History of Modern AI and Deep Learning". arXiv : 2212.11279 [ cs.NE ].
11. ^ Stigler SM (1986). The History of Statistics: The Measurement of Uncertainty before 1900 . Cambridge: Harvard. ISBN 0-674-40340-1 .
12. ^ McCulloch W, Walter Pitts (1943). "A Logical Calculus of Ideas Immanent in Nervous Activity". Bulletin of Mathematical Biophysics . 5 (4): 115–133. doi : 10.1007/BF02478259 .
13. ^ Kleene S (1956). "Representation of Events in Nerve Nets and Finite Automata" . Annals of Mathematics Studies . No. 34. Princeton University Press. pp. 3–41 . Retrieved 17 June 2017 .
14. ^ Hebb D (1949). The Organization of Behavior . New York: Wiley. ISBN 978-1-135-63190-1 .
15. ^ Farley B, W.A. Clark (1954). "Simulation of Self-Organizing Systems by Digital Computer". IRE Transactions on Information Theory . 4 (4): 76–84. doi : 10.1109/TIT.1954.1057468 .
16. ^ Rochester N, J.H. Holland, L.H. Habit and W.L. Duda (1956). "Tests on a cell assembly theory of the action of the brain, using a large digital computer". IRE Transactions on Information Theory . 2 (3): 80–93. doi : 10.1109/TIT.1956.1056810 .
17. ^ Haykin (2008) Neural Networks and Learning Machines, 3rd edition
18. ^ Rosenblatt F (1958). "The Perceptron: A Probabilistic Model For Information Storage And Organization in the Brain". Psychological Review . 65 (6): 386–408. CiteSeerX 10.1.1.588.3775 . doi : 10.1037/h0042519 . PMID 13602029 . S2CID 12781225 .
19. ^ Werbos P (1975). Beyond Regression: New Tools for Prediction and Analysis in the Behavioral Sciences .
20. ^ Rosenblatt F (1957). "The Perceptron—a perceiving and recognizing automaton". Report 85-460-1 . Cornell Aeronautical Laboratory.
21. ^ Olazaran M (1996). "A Sociological Study of the Official History of the Perceptrons Controversy". Social Studies of Science . 26 (3): 611–659. doi : 10.1177/030631296026003005 . JSTOR 285702 . S2CID 16786738 .
22. ^ a b Russel, Stuart, Norvig, Peter (2010). Artificial Intelligence A Modern Approach (PDF) (3rd ed.). United States of America: Pearson Education. pp. 16–28. ISBN 978-0-13-604259-4 .
23. ^ Minsky M, Papert S (1969). Perceptrons: An Introduction to Computational Geometry . MIT Press. ISBN 978-0-262-63022-1 .
24. ^ a b Russell SJ, Norvig P (2021). Artificial intelligence: a modern approach . Pearson Series in Artificial Intelligence. Ming-wei Chang, Jacob Devlin, Anca Dragan, David Forsyth, Ian Goodfellow, Jitendra Malik, Vikash Mansinghka, Judea Pearl, Michael J. Wooldridge (4th ed.). Hoboken, NJ: Pearson. ISBN 978-0-13-461099-3 .
25. ^ Giacaglia, G.P. (2 November 2022). Making Things Think . Holloway. ISBN 978-1-952120-41-1 . Retrieved 29 December 2023 .
26. ^ a b c Schmidhuber J (2015). "Deep Learning in Neural Networks: An Overview". Neural Networks . 61 : 85–117. arXiv : 1404.7828 . doi : 10.1016/j.neunet.2014.09.003 . PMID 25462637 . S2CID 11715509 .
27. ^ Ivakhnenko AG (1973). Cybernetic Predicting Devices . CCM Information Corporation.
28. ^ Ivakhnenko AG, Lapa VG (1967). Cybernetics and forecasting techniques . American Elsevier Pub. Co.
29. ^ Robbins H , Monro S (1951). "A Stochastic Approximation Method" . The Annals of Mathematical Statistics . 22 (3): 400. doi : 10.1214/aoms/1177729586 .
30. ^ Amari S (1967). "A theory of adaptive pattern classifier". IEEE Transactions . EC (16): 279–307.
31. ^ a b Schmidhuber J (2022). "Annotated History of Modern AI and Deep Learning". arXiv : 2212.11279 [ cs.NE ].
32. ^ a b Kohonen T, Honkela T (2007). "Kohonen Network" . Scholarpedia . 2 (1): 1568. Bibcode : 2007SchpJ...2.1568K . doi : 10.4249/scholarpedia.1568 .
33. ^ Kohonen T (1982). "Self-Organized Formation of Topologically Correct Feature Maps". Biological Cybernetics . 43 (1): 59–69. doi : 10.1007/bf00337288 . S2CID 206775459 .
34. ^ Von der Malsburg C (1973). "Self-organization of orientation sensitive cells in the striate cortex". Kybernetik . 14 (2): 85–100. doi : 10.1007/bf00288907 . PMID 4786750 . S2CID 3351573 .
35. ^ Fukushima K (1980). "Neocognitron: A Self-organizing Neural Network Model for a Mechanism of Pattern Recognition Unaffected by Shift in Position" (PDF) . Biological Cybernetics . 36 (4): 193–202. doi : 10.1007/BF00344251 . PMID 7370364 . S2CID 206775608 . Retrieved 16 November 2013 .
36. ^ Fukushima K (1969). "Visual feature extraction by a multilayered network of analog threshold elements". IEEE Transactions on Systems Science and Cybernetics . 5 (4): 322–333. doi : 10.1109/TSSC.1969.300225 .
37. ^ Ramachandran P, Barret Z, Quoc VL (16 October 2017). "Searching for Activation Functions". arXiv : 1710.05941 [ cs.NE ].
38. ^ Leibniz GW (1920). The Early Mathematical Manuscripts of Leibniz: Translated from the Latin Texts Published by Carl Immanuel Gerhardt with Critical and Historical Notes (Leibniz published the chain rule in a 1676 memoir) . Open court publishing Company. ISBN 978-0-598-81846-1 .
39. ^ Linnainmaa S (1970). The representation of the cumulative rounding error of an algorithm as a Taylor expansion of the local rounding errors (Masters) (in Finnish). University of Helsinki. pp. 6–7.
40. ^ Linnainmaa S (1976). "Taylor expansion of the accumulated rounding error". BIT Numerical Mathematics . 16 (2): 146–160. doi : 10.1007/bf01931367 . S2CID 122357351 .
41. ^ Griewank A (2012). "Who Invented the Reverse Mode of Differentiation?". Optimization Stories . Documenta Matematica, Extra Volume ISMP. pp. 389–400. S2CID 15568746 .
42. ^ Griewank A, Walther A (2008). Evaluating Derivatives: Principles and Techniques of Algorithmic Differentiation, Second Edition . SIAM. ISBN 978-0-89871-776-1 .
43. ^ Rosenblatt F (1962). Principles of Neurodynamics . Spartan, New York.
44. ^ Kelley HJ (1960). "Gradient theory of optimal flight paths". ARS Journal . 30 (10): 947–954. doi : 10.2514/8.5282 .
45. ^ "A gradient method for optimizing multi-stage allocation processes". Proceedings of the Harvard Univ. Symposium on digital computers and their applications . April 1961.
46. ^ a b c Schmidhuber J (2015). "Deep Learning" . Scholarpedia . 10 (11): 85–117. Bibcode : 2015SchpJ..1032832S . doi : 10.4249/scholarpedia.32832 .
47. ^ Dreyfus SE (1 September 1990). "Artificial neural networks, back propagation, and the Kelley-Bryson gradient procedure". Journal of Guidance, Control, and Dynamics . 13 (5): 926–928. Bibcode : 1990JGCD...13..926D . doi : 10.2514/3.25422 . ISSN 0731-5090 .
48. ^ Mizutani E, Dreyfus S , Nishio K (2000). "On derivation of MLP backpropagation from the Kelley-Bryson optimal-control gradient formula and its application". Proceedings of the IEEE-INNS-ENNS International Joint Conference on Neural Networks. IJCNN 2000. Neural Computing: New Challenges and Perspectives for the New Millennium . IEEE. pp. 167–172 vol.2. doi : 10.1109/ijcnn.2000.857892 . ISBN 0-7695-0619-4 . S2CID 351146 .
49. ^ Dreyfus S (1973). "The computational solution of optimal control problems with time lag". IEEE Transactions on Automatic Control . 18 (4): 383–385. doi : 10.1109/tac.1973.1100330 .
50. ^ Werbos P (1982). "Applications of advances in nonlinear sensitivity analysis" (PDF) . System modeling and optimization . Springer. pp. 762–770. Archived (PDF) from the original on 14 April 2016 . Retrieved 2 July 2017 .
51. ^ David E. Rumelhart, Geoffrey E. Hinton & Ronald J. Williams, " Learning representations by back-propagating errors Archived 8 March 2021 at the Wayback Machine ," Nature , 323, pages 533–536 1986.
52. ^ Brush SG (1967). "History of the Lenz-Ising Model". Reviews of Modern Physics . 39 (4): 883–893. Bibcode : 1967RvMP...39..883B . doi : 10.1103/RevModPhys.39.883 .
53. ^ Amari SI (1972). "Learning patterns and pattern sequences by self-organizing nets of threshold elements". IEEE Transactions . C (21): 1197–1206.
54. ^ Barth PF (1981). Cooperativity and the Transition Behavior of Large Neural Nets (MS thesis). Burlington: University of Vermont. OCLC 8231704 .
55. ^ Krizan J, Barth P , Glasser M (1983). "Exact Phase Transitions for the Ising Model on the Closed Cayley Tree". Physica . 119A . North-Holland Publishing Co.: 230–242. doi : 10.1016/0378-4371(83)90157-7 .
56. ^ Glasser M, Goldberg M (1983), "The Ising model on a closed Cayley tree", Physica , 117A (2–3): 670–672, Bibcode : 1983PhyA..117..670G , doi : 10.1016/0378-4371(83)90138-3
57. ^ Hopfield JJ (1982). "Neural networks and physical systems with emergent collective computational abilities" . Proceedings of the National Academy of Sciences . 79 (8): 2554–2558. Bibcode : 1982PNAS...79.2554H . doi : 10.1073/pnas.79.8.2554 . PMC 346238 . PMID 6953413 .
58. ^ Waibel A (December 1987). Phoneme Recognition Using Time-Delay Neural Networks . Meeting of the Institute of Electrical, Information and Communication Engineers (IEICE). Tokyo, Japan.
59. ^ Alexander Waibel et al., Phoneme Recognition Using Time-Delay Neural Networks IEEE Transactions on Acoustics, Speech, and Signal Processing, Volume 37, No. 3, pp. 328. – 339 March 1989.
60. ^ Zhang W (1988). "Shift-invariant pattern recognition neural network and its optical architecture" . Proceedings of Annual Conference of the Japan Society of Applied Physics .
61. ^ Zhang W (1990). "Parallel distributed processing model with local space-invariant interconnections and its optical architecture" . Applied Optics . 29 (32): 4790–7. Bibcode : 1990ApOpt..29.4790Z . doi : 10.1364/AO.29.004790 . PMID 20577468 .
62. ^ LeCun et al. , "Backpropagation Applied to Handwritten Zip Code Recognition," Neural Computation , 1, pp. 541–551, 1989.
63. ^ J. Weng, N. Ahuja and T. S. Huang, " Cresceptron: a self-organizing neural network which grows adaptively Archived 21 September 2017 at the Wayback Machine ," Proc. International Joint Conference on Neural Networks , Baltimore, Maryland, vol I, pp. 576–581, June 1992.
64. ^ J. Weng, N. Ahuja and T. S. Huang, " Learning recognition and segmentation of 3-D objects from 2-D images Archived 21 September 2017 at the Wayback Machine ," Proc. 4th International Conf. Computer Vision , Berlin, Germany, pp. 121–128, May 1993.
65. ^ J. Weng, N. Ahuja and T. S. Huang, " Learning recognition and segmentation using the Cresceptron Archived 25 January 2021 at the Wayback Machine ," International Journal of Computer Vision , vol. 25, no. 2, pp. 105–139, Nov. 1997.
66. ^ LeCun Y, Léon Bottou, Yoshua Bengio, Patrick Haffner (1998). "Gradient-based learning applied to document recognition" (PDF) . Proceedings of the IEEE . 86 (11): 2278–2324. CiteSeerX 10.1.1.32.9552 . doi : 10.1109/5.726791 . S2CID 14542261 . Retrieved 7 October 2016 .
67. ^ Qian, Ning, and Terrence J. Sejnowski. "Predicting the secondary structure of globular proteins using neural network models." Journal of molecular biology 202, no. 4 (1988): 865-884.
68. ^ Bohr, Henrik, Jakob Bohr, Søren Brunak, Rodney MJ Cotterill, Benny Lautrup, Leif Nørskov, Ole H. Olsen, and Steffen B. Petersen. "Protein secondary structure and homology by neural networks The α-helices in rhodopsin." FEBS letters 241, (1988): 223-228
69. ^ Rost, Burkhard, and Chris Sander. "Prediction of protein secondary structure at better than 70% accuracy." Journal of molecular biology 232, no. 2 (1993): 584-599.
70. ^ a b S. Hochreiter., " Untersuchungen zu dynamischen neuronalen Netzen Archived 2015-03-06 at the Wayback Machine ," Diploma thesis. Institut f. Informatik, Technische Univ. Munich. Advisor: J. Schmidhuber , 1991.
71. ^ Hochreiter S, et al. (15 January 2001). "Gradient flow in recurrent nets: the difficulty of learning long-term dependencies" . In Kolen JF, Kremer SC (eds.). A Field Guide to Dynamical Recurrent Networks . John Wiley & Sons. ISBN 978-0-7803-5369-5 .
72. ^ Schmidhuber J (1991). "A possibility for implementing curiosity and boredom in model-building neural controllers". Proc. SAB'1991 . MIT Press/Bradford Books. pp. 222–227.
73. ^ Schmidhuber J (2010). "Formal Theory of Creativity, Fun, and Intrinsic Motivation (1990-2010)". IEEE Transactions on Autonomous Mental Development . 2 (3): 230–247. doi : 10.1109/TAMD.2010.2056368 . S2CID 234198 .
74. ^ Schmidhuber J (2020). "Generative Adversarial Networks are Special Cases of Artificial Curiosity (1990) and also Closely Related to Predictability Minimization (1991)". Neural Networks . 127 : 58–66. arXiv : 1906.04493 . doi : 10.1016/j.neunet.2020.04.008 . PMID 32334341 . S2CID 216056336 .
75. ^ a b Schmidhuber J (1992). "Learning complex, extended sequences using the principle of history compression" (PDF) . Neural Computation . 4 (2): 234–242. doi : 10.1162/neco.1992.4.2.234 . S2CID 18271205 . [ permanent dead link ]
76. ^ Schmidhuber J (1 November 1992). "Learning to control fast-weight memories: an alternative to recurrent nets". Neural Computation . 4 (1): 131–139. doi : 10.1162/neco.1992.4.1.131 . S2CID 16683347 .
77. ^ Schlag I, Irie K, Schmidhuber J (2021). "Linear Transformers Are Secretly Fast Weight Programmers". ICML 2021 . Springer. pp. 9355–9366.
78. ^ Choromanski K, Likhosherstov V, Dohan D, Song X, Gane A, Sarlos T, et al. (2020). "Rethinking Attention with Performers". arXiv : 2009.14794 [ cs.CL ].
79. ^ Schmidhuber J (1993). "Reducing the ratio between learning complexity and number of time-varying variables in fully recurrent nets". ICANN 1993 . Springer. pp. 460–463.
80. ^ Mead CA , Ismail M (8 May 1989). Analog VLSI Implementation of Neural Systems (PDF) . The Kluwer International Series in Engineering and Computer Science. Vol. 80. Norwell, MA: Kluwer Academic Publishers . doi : 10.1007/978-1-4613-1639-8 . ISBN 978-1-4613-1639-8 . Archived (PDF) from the original on 6 November 2019 . Retrieved 24 January 2020 .
81. ^ Domingos P (22 September 2015). "chapter 4". The Master Algorithm: How the Quest for the Ultimate Learning Machine Will Remake Our World . Basic Books . ISBN 978-0-465-06570-7 .
82. ^ Hochreiter S, Schmidhuber J (1 November 1997). "Long Short-Term Memory". Neural Computation . 9 (8): 1735–1780. doi : 10.1162/neco.1997.9.8.1735 . ISSN 0899-7667 . PMID 9377276 . S2CID 1915014 .
83. ^ Schmidhuber J (2015). "Deep Learning in Neural Networks: An Overview". Neural Networks . 61 : 85–117. arXiv : 1404.7828 . doi : 10.1016/j.neunet.2014.09.003 . PMID 25462637 . S2CID 11715509 .
84. ^ Gers F, Schmidhuber J, Cummins F (1999). "Learning to forget: Continual prediction with LSTM". 9th International Conference on Artificial Neural Networks: ICANN '99 . Vol. 1999. pp. 850–855. doi : 10.1049/cp:19991218 . ISBN 0-85296-721-7 .
85. ^ Smolensky P (1986). "Information processing in dynamical systems: Foundations of harmony theory." . In D. E. Rumelhart, J. L. McClelland, PDP Research Group (eds.). Parallel Distributed Processing: Explorations in the Microstructure of Cognition . Vol. 1. pp. 194–281 . ISBN 978-0-262-68053-0 .
86. ^ Ng A, Dean J (2012). "Building High-level Features Using Large Scale Unsupervised Learning". arXiv : 1112.6209 [ cs.LG ].
87. ^ Hinton GE , Osindero S, Teh Y (2006). "A fast learning algorithm for deep belief nets" (PDF) . Neural Computation . 18 (7): 1527–1554. CiteSeerX 10.1.1.76.1541 . doi : 10.1162/neco.2006.18.7.1527 . PMID 16764513 . S2CID 2309950 .
88. ^ Fukushima K (1980). "Neocognitron: A self-organizing neural network model for a mechanism of pattern recognition unaffected by shift in position". Biological Cybernetics . 36 (4): 93–202. doi : 10.1007/BF00344251 . PMID 7370364 . S2CID 206775608 .
89. ^ Riesenhuber M, Poggio T (1999). "Hierarchical models of object recognition in cortex". Nature Neuroscience . 2 (11): 1019–1025. doi : 10.1038/14819 . PMID 10526343 . S2CID 8920227 .
90. ^ Yang JJ, Pickett MD, Li XM, Ohlberg DA, Stewart DR, Williams RS (2008). "Memristive switching mechanism for metal/oxide/metal nanodevices". Nat. Nanotechnol. 3 (7): 429–433. doi : 10.1038/nnano.2008.160 . PMID 18654568 .
91. ^ Strukov DB, Snider GS, Stewart DR, Williams RS (2008). "The missing memristor found". Nature . 453 (7191): 80–83. Bibcode : 2008Natur.453...80S . doi : 10.1038/nature06932 . PMID 18451858 . S2CID 4367148 .
92. ^ Cireşan DC, Meier U, Gambardella LM, Schmidhuber J (21 September 2010). "Deep, Big, Simple Neural Nets for Handwritten Digit Recognition". Neural Computation . 22 (12): 3207–3220. arXiv : 1003.0358 . doi : 10.1162/neco_a_00052 . ISSN 0899-7667 . PMID 20858131 . S2CID 1918673 .
93. ^ Dominik Scherer, Andreas C. Müller, and Sven Behnke: " Evaluation of Pooling Operations in Convolutional Architectures for Object Recognition Archived 3 April 2018 at the Wayback Machine ," In 20th International Conference Artificial Neural Networks (ICANN) , pp. 92–101, 2010. doi : 10.1007/978-3-642-15825-4_10 .
94. ^ 2012 Kurzweil AI Interview Archived 31 August 2018 at the Wayback Machine with Juergen Schmidhuber on the eight competitions won by his Deep Learning team 2009–2012
95. ^ "How bio-inspired deep learning keeps winning competitions | KurzweilAI" . www.kurzweilai.net . Archived from the original on 31 August 2018 . Retrieved 16 June 2017 .
96. ^ a b Graves A, Schmidhuber J (2009). "Offline Handwriting Recognition with Multidimensional Recurrent Neural Networks" (PDF) . In Koller D, Schuurmans D, Bengio Y, Bottou L (eds.). Advances in Neural Information Processing Systems 21 (NIPS 2008) . Neural Information Processing Systems (NIPS) Foundation. pp. 545–552. ISBN 978-1-60560-949-2 .
97. ^ a b Graves A, Liwicki M, Fernandez S, Bertolami R, Bunke H, Schmidhuber J (May 2009). "A Novel Connectionist System for Unconstrained Handwriting Recognition" (PDF) . IEEE Transactions on Pattern Analysis and Machine Intelligence . 31 (5): 855–868. CiteSeerX 10.1.1.139.4502 . doi : 10.1109/tpami.2008.137 . ISSN 0162-8828 . PMID 19299860 . S2CID 14635907 . Archived (PDF) from the original on 2 January 2014 . Retrieved 30 July 2014 .
98. ^ Ciresan D, Meier U, Schmidhuber J (June 2012). "Multi-column deep neural networks for image classification". 2012 IEEE Conference on Computer Vision and Pattern Recognition . pp. 3642–3649. arXiv : 1202.2745 . Bibcode : 2012arXiv1202.2745C . CiteSeerX 10.1.1.300.3283 . doi : 10.1109/cvpr.2012.6248110 . ISBN 978-1-4673-1228-8 . S2CID 2161592 .
99. ^ a b Billings SA (2013). Nonlinear System Identification: NARMAX Methods in the Time, Frequency, and Spatio-Temporal Domains . Wiley. ISBN 978-1-119-94359-4 .
100. ^ a b Goodfellow I, Pouget-Abadie J, Mirza M, Xu B, Warde-Farley D, Ozair S, et al. (2014). Generative Adversarial Networks (PDF) . Proceedings of the International Conference on Neural Information Processing Systems (NIPS 2014). pp. 2672–2680. Archived (PDF) from the original on 22 November 2019 . Retrieved 20 August 2019 .
101. ^ "Prepare, Don't Panic: Synthetic Media and Deepfakes" . witness.org. Archived from the original on 2 December 2020 . Retrieved 25 November 2020 .
102. ^ "GAN 2.0: NVIDIA's Hyperrealistic Face Generator" . SyncedReview.com . 14 December 2018 . Retrieved 3 October 2019 .
103. ^ Karras T, Aila T, Laine S, Lehtinen J (1 October 2017). "Progressive Growing of GANs for Improved Quality, Stability, and Variation". arXiv : 1710.10196 [ cs.NE ].
104. ^ Srivastava RK, Greff K, Schmidhuber J (2 May 2015). "Highway Networks". arXiv : 1505.00387 [ cs.LG ].
105. ^ Srivastava RK, Greff K, Schmidhuber J (2015). "Training Very Deep Networks" . Advances in Neural Information Processing Systems . 28 . Curran Associates, Inc.: 2377–2385.
106. ^ He K, Zhang X, Ren S, Sun J (2016). Deep Residual Learning for Image Recognition . 2016 IEEE Conference on Computer Vision and Pattern Recognition (CVPR) . Las Vegas, NV, US: IEEE. pp. 770–778. arXiv : 1512.03385 . doi : 10.1109/CVPR.2016.90 . ISBN 978-1-4673-8851-1 .
107. ^ Vaswani A, Shazeer N, Parmar N, Uszkoreit J, Jones L, Gomez AN, et al. (12 June 2017). "Attention Is All You Need". arXiv : 1706.03762 [ cs.CL ].
108. ^ Wolf T, Debut L, Sanh V, Chaumond J, Delangue C, Moi A, et al. (2020). "Transformers: State-of-the-Art Natural Language Processing". Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing: System Demonstrations . pp. 38–45. doi : 10.18653/v1/2020.emnlp-demos.6 . S2CID 208117506 .
109. ^ He C (31 December 2021). "Transformer in CV" . Transformer in CV . Towards Data Science.
110. ^ [Ramezanpour, A.; Beam, A.L.; Chen, J.H.; Mashaghi, A. Statistical Physics for Medical Diagnostics: Learning, Inference, and Optimization Algorithms. Diagnostics 2020, 10, 972. ]
111. ^ a b Zell A (2003). "chapter 5.2". Simulation neuronaler Netze [ Simulation of Neural Networks ] (in German) (1st ed.). Addison-Wesley. ISBN 978-3-89319-554-1 . OCLC 249017987 .
112. ^ Artificial intelligence (3rd ed.). Addison-Wesley Pub. Co. 1992. ISBN 0-201-53377-4 .
113. ^ Abbod MF (2007). "Application of Artificial Intelligence to the Management of Urological Cancer". The Journal of Urology . 178 (4): 1150–1156. doi : 10.1016/j.juro.2007.05.122 . PMID 17698099 .
114. ^ Dawson CW (1998). "An artificial neural network approach to rainfall-runoff modelling" . Hydrological Sciences Journal . 43 (1): 47–66. Bibcode : 1998HydSJ..43...47D . doi : 10.1080/02626669809492102 .
115. ^ "The Machine Learning Dictionary" . www.cse.unsw.edu.au . Archived from the original on 26 August 2018 . Retrieved 4 November 2009 .
116. ^ Ciresan D, Ueli Meier, Jonathan Masci, Luca M. Gambardella, Jurgen Schmidhuber (2011). "Flexible, High Performance Convolutional Neural Networks for Image Classification" (PDF) . Proceedings of the Twenty-Second International Joint Conference on Artificial Intelligence-Volume Volume Two . 2 : 1237–1242. Archived (PDF) from the original on 5 April 2022 . Retrieved 7 July 2022 .
117. ^ Zell A (1994). Simulation Neuronaler Netze [ Simulation of Neural Networks ] (in German) (1st ed.). Addison-Wesley. p. 73. ISBN 3-89319-554-8 .
118. ^ Miljanovic M (February–March 2012). "Comparative analysis of Recurrent and Finite Impulse Response Neural Networks in Time Series Prediction" (PDF) . Indian Journal of Computer and Engineering . 3 (1).
119. ^ Lau S (10 July 2017). "A Walkthrough of Convolutional Neural Network – Hyperparameter Tuning" . Medium . Archived from the original on 4 February 2023 . Retrieved 23 August 2019 .
120. ^ Kelleher JD, Mac Namee B, D'Arcy A (2020). "7-8". Fundamentals of machine learning for predictive data analytics: algorithms, worked examples, and case studies (2nd ed.). Cambridge, MA: The MIT Press. ISBN 978-0-262-36110-1 . OCLC 1162184998 .
121. ^ Wei J (26 April 2019). "Forget the Learning Rate, Decay Loss". arXiv : 1905.00094 [ cs.LG ].
122. ^ Li Y, Fu Y, Li H, Zhang SW (1 June 2009). "The Improved Training Algorithm of Back Propagation Neural Network with Self-adaptive Learning Rate". 2009 International Conference on Computational Intelligence and Natural Computing . Vol. 1. pp. 73–76. doi : 10.1109/CINC.2009.111 . ISBN 978-0-7695-3645-3 . S2CID 10557754 .
123. ^ Huang GB, Zhu QY, Siew CK (2006). "Extreme learning machine: theory and applications". Neurocomputing . 70 (1): 489–501. CiteSeerX 10.1.1.217.3692 . doi : 10.1016/j.neucom.2005.12.126 . S2CID 116858 .
124. ^ Widrow B, et al. (2013). "The no-prop algorithm: A new learning algorithm for multilayer neural networks". Neural Networks . 37 : 182–188. doi : 10.1016/j.neunet.2012.09.020 . PMID 23140797 .
125. ^ Ollivier Y, Charpiat G (2015). "Training recurrent networks without backtracking". arXiv : 1507.07680 [ cs.NE ].
126. ^ Hinton GE (2010). "A Practical Guide to Training Restricted Boltzmann Machines" . Tech. Rep. UTML TR 2010-003 . Archived from the original on 9 May 2021 . Retrieved 27 June 2017 .
127. ^ ESANN. 2009. [ full citation needed ]
128. ^ Bernard E (2021). Introduction to machine learning . Champaign: Wolfram Media. p. 9. ISBN 978-1-57955-048-6 . Retrieved 22 March 2023 .
129. ^ Bernard E (2021). Introduction to machine learning . Champaign: Wolfram Media. p. 12. ISBN 978-1-57955-048-6 . Retrieved 22 March 2023 .
130. ^ Bernard E (2021). Introduction to Machine Learning . Wolfram Media Inc. p. 9. ISBN 978-1-57955-048-6 .
131. ^ Ojha VK, Abraham A, Snášel V (1 April 2017). "Metaheuristic design of feedforward neural networks: A review of two decades of research". Engineering Applications of Artificial Intelligence . 60 : 97–116. arXiv : 1705.05584 . Bibcode : 2017arXiv170505584O . doi : 10.1016/j.engappai.2017.01.013 . S2CID 27910748 .
132. ^ Dominic, S., Das, R., Whitley, D., Anderson, C. (July 1991). "Genetic reinforcement learning for neural networks" . IJCNN-91-Seattle International Joint Conference on Neural Networks . IJCNN-91-Seattle International Joint Conference on Neural Networks. Seattle, Washington, US: IEEE. pp. 71–76. doi : 10.1109/IJCNN.1991.155315 . ISBN 0-7803-0164-1 .
133. ^ Hoskins J, Himmelblau, D.M. (1992). "Process control via artificial neural networks and reinforcement learning". Computers & Chemical Engineering . 16 (4): 241–251. doi : 10.1016/0098-1354(92)80045-B .
134. ^ Bertsekas D, Tsitsiklis J (1996). Neuro-dynamic programming . Athena Scientific. p. 512. ISBN 978-1-886529-10-6 . Archived from the original on 29 June 2017 . Retrieved 17 June 2017 .
135. ^ Secomandi N (2000). "Comparing neuro-dynamic programming algorithms for the vehicle routing problem with stochastic demands". Computers & Operations Research . 27 (11–12): 1201–1225. CiteSeerX 10.1.1.392.4034 . doi : 10.1016/S0305-0548(99)00146-X .
136. ^ de Rigo, D., Rizzoli, A. E., Soncini-Sessa, R., Weber, E., Zenesi, P. (2001). "Neuro-dynamic programming for the efficient management of reservoir networks" . Proceedings of MODSIM 2001, International Congress on Modelling and Simulation . MODSIM 2001, International Congress on Modelling and Simulation. Canberra, Australia: Modelling and Simulation Society of Australia and New Zealand. doi : 10.5281/zenodo.7481 . ISBN 0-86740-525-2 . Archived from the original on 7 August 2013 . Retrieved 29 July 2013 .
137. ^ Damas, M., Salmeron, M., Diaz, A., Ortega, J., Prieto, A., Olivares, G. (2000). "Genetic algorithms and neuro-dynamic programming: application to water supply networks". Proceedings of 2000 Congress on Evolutionary Computation . 2000 Congress on Evolutionary Computation. Vol. 1. La Jolla, California, US: IEEE. pp. 7–14. doi : 10.1109/CEC.2000.870269 . ISBN 0-7803-6375-2 .
138. ^ Deng G, Ferris, M.C. (2008). "Neuro-dynamic programming for fractionated radiotherapy planning". Optimization in Medicine . Springer Optimization and Its Applications. Vol. 12. pp. 47–70. CiteSeerX 10.1.1.137.8288 . doi : 10.1007/978-0-387-73299-2_3 . ISBN 978-0-387-73298-5 .
139. ^ Bozinovski, S. (1982). "A self-learning system using secondary reinforcement". In R. Trappl (ed.) Cybernetics and Systems Research: Proceedings of the Sixth European Meeting on Cybernetics and Systems Research. North Holland. pp. 397–402. ISBN 978-0-444-86488-8 .
140. ^ Bozinovski, S. (2014) " Modeling mechanisms of cognition-emotion interaction in artificial neural networks, since 1981 Archived 23 March 2019 at the Wayback Machine ." Procedia Computer Science p. 255-263
141. ^ Bozinovski S, Bozinovska L (2001). "Self-learning agents: A connectionist theory of emotion based on crossbar value judgment". Cybernetics and Systems . 32 (6): 637–667. doi : 10.1080/01969720118145 . S2CID 8944741 .
142. ^ "Artificial intelligence can 'evolve' to solve problems" . Science | AAAS . 10 January 2018. Archived from the original on 9 December 2021 . Retrieved 7 February 2018 .
143. ^ Turchetti C (2004), Stochastic Models of Neural Networks , Frontiers in artificial intelligence and applications: Knowledge-based intelligent engineering systems, vol. 102, IOS Press, ISBN 978-1-58603-388-0
144. ^ Jospin LV, Laga H, Boussaid F, Buntine W, Bennamoun M (2022). "Hands-On Bayesian Neural Networks—A Tutorial for Deep Learning Users". IEEE Computational Intelligence Magazine . Vol. 17, no. 2. pp. 29–48. arXiv : 2007.06823 . doi : 10.1109/mci.2022.3155327 . ISSN 1556-603X . S2CID 220514248 .
145. ^ de Rigo, D., Castelletti, A., Rizzoli, A. E., Soncini-Sessa, R., Weber, E. (January 2005). "A selective improvement technique for fastening Neuro-Dynamic Programming in Water Resources Network Management" . In Pavel Zítek (ed.). Proceedings of the 16th IFAC World Congress – IFAC-PapersOnLine . 16th IFAC World Congress . Vol. 16. Prague, Czech Republic: IFAC. pp. 7–12. doi : 10.3182/20050703-6-CZ-1902.02172 . hdl : 11311/255236 . ISBN 978-3-902661-75-3 . Archived from the original on 26 April 2012 . Retrieved 30 December 2011 .
146. ^ Ferreira C (2006). "Designing Neural Networks Using Gene Expression Programming". In A. Abraham, B. de Baets, M. Köppen, B. Nickolay (eds.). Applied Soft Computing Technologies: The Challenge of Complexity (PDF) . Springer-Verlag. pp. 517–536. Archived (PDF) from the original on 19 December 2013 . Retrieved 8 October 2012 .
147. ^ Da, Y., Xiurun, G. (July 2005). "An improved PSO-based ANN with simulated annealing technique" . In T. Villmann (ed.). New Aspects in Neurocomputing: 11th European Symposium on Artificial Neural Networks . Vol. 63. Elsevier. pp. 527–533. doi : 10.1016/j.neucom.2004.07.002 . Archived from the original on 25 April 2012 . Retrieved 30 December 2011 .
148. ^ Wu, J., Chen, E. (May 2009). "A Novel Nonparametric Regression Ensemble for Rainfall Forecasting Using Particle Swarm Optimization Technique Coupled with Artificial Neural Network" . In Wang, H., Shen, Y., Huang, T., Zeng, Z. (eds.). 6th International Symposium on Neural Networks, ISNN 2009 . Lecture Notes in Computer Science. Vol. 5553. Springer. pp. 49–58. doi : 10.1007/978-3-642-01513-7_6 . ISBN 978-3-642-01215-0 . Archived from the original on 31 December 2014 . Retrieved 1 January 2012 .
149. ^ a b Ting Qin, Zonghai Chen, Haitao Zhang, Sifu Li, Wei Xiang, Ming Li (2004). "A learning algorithm of CMAC based on RLS" (PDF) . Neural Processing Letters . 19 (1): 49–61. doi : 10.1023/B:NEPL.0000016847.18175.60 . S2CID 6233899 . Archived (PDF) from the original on 14 April 2021 . Retrieved 30 January 2019 .
150. ^ Ting Qin, Haitao Zhang, Zonghai Chen, Wei Xiang (2005). "Continuous CMAC-QRLS and its systolic array" (PDF) . Neural Processing Letters . 22 (1): 1–16. doi : 10.1007/s11063-004-2694-0 . S2CID 16095286 . Archived (PDF) from the original on 18 November 2018 . Retrieved 30 January 2019 .
151. ^ LeCun Y, Boser B, Denker JS, Henderson D, Howard RE, Hubbard W, et al. (1989). "Backpropagation Applied to Handwritten Zip Code Recognition". Neural Computation . 1 (4): 541–551. doi : 10.1162/neco.1989.1.4.541 . S2CID 41312633 .
152. ^ Yann LeCun (2016). Slides on Deep Learning Online Archived 23 April 2016 at the Wayback Machine
153. ^ Hochreiter S , Schmidhuber J (1 November 1997). "Long Short-Term Memory". Neural Computation . 9 (8): 1735–1780. doi : 10.1162/neco.1997.9.8.1735 . ISSN 0899-7667 . PMID 9377276 . S2CID 1915014 .
154. ^ Sak H, Senior A, Beaufays F (2014). "Long Short-Term Memory recurrent neural network architectures for large scale acoustic modeling" (PDF) . Archived from the original (PDF) on 24 April 2018.
155. ^ Li X, Wu X (15 October 2014). "Constructing Long Short-Term Memory based Deep Recurrent Neural Networks for Large Vocabulary Speech Recognition". arXiv : 1410.4281 [ cs.CL ].
156. ^ Fan Y, Qian Y, Xie F, Soong FK (2014). "TTS synthesis with bidirectional LSTM based Recurrent Neural Networks" . Proceedings of the Annual Conference of the International Speech Communication Association, Interspeech : 1964–1968 . Retrieved 13 June 2017 .
157. ^ Zen H, Sak H (2015). "Unidirectional Long Short-Term Memory Recurrent Neural Network with Recurrent Output Layer for Low-Latency Speech Synthesis" (PDF) . Google.com . ICASSP. pp. 4470–4474. Archived (PDF) from the original on 9 May 2021 . Retrieved 27 June 2017 .
158. ^ Fan B, Wang L, Soong FK, Xie L (2015). "Photo-Real Talking Head with Deep Bidirectional LSTM" (PDF) . Proceedings of ICASSP . Archived (PDF) from the original on 1 November 2017 . Retrieved 27 June 2017 .
159. ^ Silver D , Hubert T, Schrittwieser J, Antonoglou I, Lai M, Guez A, et al. (5 December 2017). "Mastering Chess and Shogi by Self-Play with a General Reinforcement Learning Algorithm". arXiv : 1712.01815 [ cs.AI ].
160. ^ Probst P, Boulesteix AL, Bischl B (26 February 2018). "Tunability: Importance of Hyperparameters of Machine Learning Algorithms". J. Mach. Learn. Res . 20 : 53:1–53:32. S2CID 88515435 .
161. ^ Zoph B, Le QV (4 November 2016). "Neural Architecture Search with Reinforcement Learning". arXiv : 1611.01578 [ cs.LG ].
162. ^ Haifeng Jin, Qingquan Song, Xia Hu (2019). "Auto-keras: An efficient neural architecture search system" . Proceedings of the 25th ACM SIGKDD International Conference on Knowledge Discovery & Data Mining . ACM. arXiv : 1806.10282 . Archived from the original on 21 August 2019 . Retrieved 21 August 2019 – via autokeras.com.
163. ^ Claesen M, De Moor B (2015). "Hyperparameter Search in Machine Learning". arXiv : 1502.02127 [ cs.LG ]. Bibcode : 2015arXiv150202127C
164. ^ Esch R (1990). "Functional Approximation". Handbook of Applied Mathematics (Springer US ed.). Boston, MA: Springer US. pp. 928–987. doi : 10.1007/978-1-4684-1423-3_17 . ISBN 978-1-4684-1423-3 .
165. ^ Sarstedt M, Moo E (2019). "Regression Analysis" . A Concise Guide to Market Research . Springer Texts in Business and Economics. Springer Berlin Heidelberg. pp. 209–256. doi : 10.1007/978-3-662-56707-4_7 . ISBN 978-3-662-56706-7 . S2CID 240396965 .
166. ^ Tian J, Tan Y, Sun C, Zeng J, Jin Y (December 2016). "A self-adaptive similarity-based fitness approximation for evolutionary optimization" . 2016 IEEE Symposium Series on Computational Intelligence (SSCI) . pp. 1–8. doi : 10.1109/SSCI.2016.7850209 . ISBN 978-1-5090-4240-1 . S2CID 14948018 .
167. ^ Alaloul WS, Qureshi AH (2019). "Data Processing Using Artificial Neural Networks" . Dynamic Data Assimilation - Beating the Uncertainties . doi : 10.5772/intechopen.91935 . ISBN 978-1-83968-083-0 . S2CID 219735060 .
168. ^ Pal M, Roy R, Basu J, Bepari MS (2013). "Blind source separation: A review and analysis" . 2013 International Conference Oriental COCOSDA held jointly with 2013 Conference on Asian Spoken Language Research and Evaluation (O-COCOSDA/CASLRE) . IEEE. pp. 1–5. doi : 10.1109/ICSDA.2013.6709849 . ISBN 978-1-4799-2378-6 . S2CID 37566823 .
169. ^ Zissis D (October 2015). "A cloud based architecture capable of perceiving and predicting multiple vessel behaviour" . Applied Soft Computing . 35 : 652–661. doi : 10.1016/j.asoc.2015.07.002 . Archived from the original on 26 July 2020 . Retrieved 18 July 2019 .
170. ^ Sengupta N, Sahidullah, Md, Saha, Goutam (August 2016). "Lung sound classification using cepstral-based statistical features". Computers in Biology and Medicine . 75 (1): 118–129. doi : 10.1016/j.compbiomed.2016.05.013 . PMID 27286184 .
171. ^ Choy, Christopher B., et al. " 3d-r2n2: A unified approach for single and multi-view 3d object reconstruction Archived 26 July 2020 at the Wayback Machine ." European conference on computer vision. Springer, Cham, 2016.
172. ^ Turek, Fred D. (March 2007). "Introduction to Neural Net Machine Vision" . Vision Systems Design . 12 (3). Archived from the original on 16 May 2013 . Retrieved 5 March 2013 .
173. ^ Maitra DS, Bhattacharya U, Parui SK (August 2015). "CNN based common approach to handwritten character recognition of multiple scripts" . 2015 13th International Conference on Document Analysis and Recognition (ICDAR) . pp. 1021–1025. doi : 10.1109/ICDAR.2015.7333916 . ISBN 978-1-4799-1805-8 . S2CID 25739012 .
174. ^ Gessler J (August 2021). "Sensor for food analysis applying impedance spectroscopy and artificial neural networks" . RiuNet UPV (1): 8–12. Archived from the original on 21 October 2021 . Retrieved 21 October 2021 .
175. ^ French J (2016). "The time traveller's CAPM". Investment Analysts Journal . 46 (2): 81–96. doi : 10.1080/10293523.2016.1255469 . S2CID 157962452 .
176. ^ Roman M. Balabin, Ekaterina I. Lomakina (2009). "Neural network approach to quantum-chemistry data: Accurate prediction of density functional theory energies". J. Chem. Phys. 131 (7): 074104. Bibcode : 2009JChPh.131g4104B . doi : 10.1063/1.3206326 . PMID 19708729 .
177. ^ Silver D, et al. (2016). "Mastering the game of Go with deep neural networks and tree search" (PDF) . Nature . 529 (7587): 484–489. Bibcode : 2016Natur.529..484S . doi : 10.1038/nature16961 . PMID 26819042 . S2CID 515925 . Archived (PDF) from the original on 23 November 2018 . Retrieved 31 January 2019 .
178. ^ Pasick A (27 March 2023). "Artificial Intelligence Glossary: Neural Networks and Other Terms Explained" . The New York Times . ISSN 0362-4331 . Retrieved 22 April 2023 .
179. ^ Schechner S (15 June 2017). "Facebook Boosts A.I. to Block Terrorist Propaganda" . The Wall Street Journal . ISSN 0099-9660 . Retrieved 16 June 2017 .
180. ^ Ganesan N (2010). "Application of Neural Networks in Diagnosing Cancer Disease Using Demographic Data" . International Journal of Computer Applications . 1 (26): 81–97. Bibcode : 2010IJCA....1z..81G . doi : 10.5120/476-783 .
181. ^ Bottaci L (1997). "Artificial Neural Networks Applied to Outcome Prediction for Colorectal Cancer Patients in Separate Institutions" (PDF) . Lancet . 350 (9076). The Lancet: 469–72. doi : 10.1016/S0140-6736(96)11196-X . PMID 9274582 . S2CID 18182063 . Archived from the original (PDF) on 23 November 2018 . Retrieved 2 May 2012 .
182. ^ Alizadeh E, Lyons SM, Castle JM, Prasad A (2016). "Measuring systematic changes in invasive cancer cell shape using Zernike moments" . Integrative Biology . 8 (11): 1183–1193. doi : 10.1039/C6IB00100A . PMID 27735002 .
183. ^ Lyons S (2016). "Changes in cell shape are correlated with metastatic potential in murine" . Biology Open . 5 (3): 289–299. doi : 10.1242/bio.013409 . PMC 4810736 . PMID 26873952 .
184. ^ Nabian MA, Meidani H (28 August 2017). "Deep Learning for Accelerated Reliability Analysis of Infrastructure Networks". Computer-Aided Civil and Infrastructure Engineering . 33 (6): 443–458. arXiv : 1708.08551 . Bibcode : 2017arXiv170808551N . doi : 10.1111/mice.12359 . S2CID 36661983 .
185. ^ Nabian MA, Meidani H (2018). "Accelerating Stochastic Assessment of Post-Earthquake Transportation Network Connectivity via Machine-Learning-Based Surrogates" . Transportation Research Board 97th Annual Meeting . Archived from the original on 9 March 2018 . Retrieved 14 March 2018 .
186. ^ Díaz E, Brotons V, Tomás R (September 2018). "Use of artificial neural networks to predict 3-D elastic settlement of foundations on soils with inclined bedrock" . Soils and Foundations . 58 (6): 1414–1422. Bibcode : 2018SoFou..58.1414D . doi : 10.1016/j.sandf.2018.08.001 . hdl : 10045/81208 . ISSN 0038-0806 .
187. ^ Tayebiyan A, Mohammad TA, Ghazali AH, Mashohor S. "Artificial Neural Network for Modelling Rainfall-Runoff" . Pertanika Journal of Science & Technology . 24 (2): 319–330.
188. ^ Govindaraju RS (1 April 2000). "Artificial Neural Networks in Hydrology. I: Preliminary Concepts". Journal of Hydrologic Engineering . 5 (2): 115–123. doi : 10.1061/(ASCE)1084-0699(2000)5:2(115) .
189. ^ Govindaraju RS (1 April 2000). "Artificial Neural Networks in Hydrology. II: Hydrologic Applications". Journal of Hydrologic Engineering . 5 (2): 124–137. doi : 10.1061/(ASCE)1084-0699(2000)5:2(124) .
190. ^ Peres DJ, Iuppa C, Cavallaro L, Cancelliere A, Foti E (1 October 2015). "Significant wave height record extension by neural networks and reanalysis wind data". Ocean Modelling . 94 : 128–140. Bibcode : 2015OcMod..94..128P . doi : 10.1016/j.ocemod.2015.08.002 .
191. ^ Dwarakish GS, Rakshith S, Natesan U (2013). "Review on Applications of Neural Network in Coastal Engineering" . Artificial Intelligent Systems and Machine Learning . 5 (7): 324–331. Archived from the original on 15 August 2017 . Retrieved 5 July 2017 .
192. ^ Ermini L, Catani F, Casagli N (1 March 2005). "Artificial Neural Networks applied to landslide susceptibility assessment". Geomorphology . Geomorphological hazard and human impact in mountain environments. 66 (1): 327–343. Bibcode : 2005Geomo..66..327E . doi : 10.1016/j.geomorph.2004.09.025 .
193. ^ Nix R, Zhang J (May 2017). "Classification of Android apps and malware using deep neural networks". 2017 International Joint Conference on Neural Networks (IJCNN) . pp. 1871–1878. doi : 10.1109/IJCNN.2017.7966078 . ISBN 978-1-5090-6182-2 . S2CID 8838479 .
194. ^ "Detecting Malicious URLs" . The systems and networking group at UCSD . Archived from the original on 14 July 2019 . Retrieved 15 February 2019 .
195. ^ Homayoun S, Ahmadzadeh M, Hashemi S, Dehghantanha A, Khayami R (2018), Dehghantanha A, Conti M, Dargahi T (eds.), "BoTShark: A Deep Learning Approach for Botnet Traffic Detection", Cyber Threat Intelligence , Advances in Information Security, vol. 70, Springer International Publishing, pp. 137–153, doi : 10.1007/978-3-319-73951-9_7 , ISBN 978-3-319-73951-9
196. ^ Ghosh, Reilly (January 1994). "Credit card fraud detection with a neural-network". Proceedings of the Twenty-Seventh Hawaii International Conference on System Sciences HICSS-94 . Vol. 3. pp. 621–630. doi : 10.1109/HICSS.1994.323314 . ISBN 978-0-8186-5090-1 . S2CID 13260377 .
197. ^ Ananthaswamy A (19 April 2021). "Latest Neural Nets Solve World's Hardest Equations Faster Than Ever Before" . Quanta Magazine . Retrieved 12 May 2021 .
198. ^ "AI has cracked a key mathematical puzzle for understanding our world" . MIT Technology Review . Retrieved 19 November 2020 .
199. ^ "Caltech Open-Sources AI for Solving Partial Differential Equations" . InfoQ . Archived from the original on 25 January 2021 . Retrieved 20 January 2021 .
200. ^ Nagy A (28 June 2019). "Variational Quantum Monte Carlo Method with a Neural-Network Ansatz for Open Quantum Systems". Physical Review Letters . 122 (25): 250501. arXiv : 1902.09483 . Bibcode : 2019PhRvL.122y0501N . doi : 10.1103/PhysRevLett.122.250501 . PMID 31347886 . S2CID 119074378 .
201. ^ Yoshioka N, Hamazaki R (28 June 2019). "Constructing neural stationary states for open quantum many-body systems". Physical Review B . 99 (21): 214306. arXiv : 1902.07006 . Bibcode : 2019PhRvB..99u4306Y . doi : 10.1103/PhysRevB.99.214306 . S2CID 119470636 .
202. ^ Hartmann MJ, Carleo G (28 June 2019). "Neural-Network Approach to Dissipative Quantum Many-Body Dynamics". Physical Review Letters . 122 (25): 250502. arXiv : 1902.05131 . Bibcode : 2019PhRvL.122y0502H . doi : 10.1103/PhysRevLett.122.250502 . PMID 31347862 . S2CID 119357494 .
203. ^ Vicentini F, Biella A, Regnault N, Ciuti C (28 June 2019). "Variational Neural-Network Ansatz for Steady States in Open Quantum Systems". Physical Review Letters . 122 (25): 250503. arXiv : 1902.10104 . Bibcode : 2019PhRvL.122y0503V . doi : 10.1103/PhysRevLett.122.250503 . PMID 31347877 . S2CID 119504484 .
204. ^ Forrest MD (April 2015). "Simulation of alcohol action upon a detailed Purkinje neuron model and a simpler surrogate model that runs >400 times faster" . BMC Neuroscience . 16 (27): 27. doi : 10.1186/s12868-015-0162-6 . PMC 4417229 . PMID 25928094 .
205. ^ Wieczorek S, Filipiak D, Filipowska A (2018). "Semantic Image-Based Profiling of Users' Interests with Neural Networks" . Studies on the Semantic Web . 36 (Emerging Topics in Semantic Technologies). doi : 10.3233/978-1-61499-894-5-179 .
206. ^ Merchant A, Batzner S, Schoenholz SS, Aykol M, Cheon G, Cubuk ED (December 2023). "Scaling deep learning for materials discovery" . Nature . 624 (7990): 80–85. Bibcode : 2023Natur.624...80M . doi : 10.1038/s41586-023-06735-9 . ISSN 1476-4687 . PMC 10700131 . PMID 38030720 .
207. ^ Siegelmann H, Sontag E (1991). "Turing computability with neural nets" (PDF) . Appl. Math. Lett . 4 (6): 77–80. doi : 10.1016/0893-9659(91)90080-F .
208. ^ Bains S (3 November 1998). "Analog computer trumps Turing model" . EE Times . Retrieved 11 May 2023 .
209. ^ Balcázar J (July 1997). "Computational Power of Neural Networks: A Kolmogorov Complexity Characterization". IEEE Transactions on Information Theory . 43 (4): 1175–1183. CiteSeerX 10.1.1.411.7782 . doi : 10.1109/18.605580 .
210. ^ a b MacKay DJ (2003). Information Theory, Inference, and Learning Algorithms (PDF) . Cambridge University Press . ISBN 978-0-521-64298-9 . Archived (PDF) from the original on 19 October 2016 . Retrieved 11 June 2016 .
211. ^ Cover T (1965). "Geometrical and Statistical Properties of Systems of Linear Inequalities with Applications in Pattern Recognition" (PDF) . IEEE Transactions on Electronic Computers . EC-14 (3). IEEE : 326–334. doi : 10.1109/PGEC.1965.264137 . Archived (PDF) from the original on 5 March 2016 . Retrieved 10 March 2020 .
212. ^ Gerald F (2019). "Reproducibility and Experimental Design for Machine Learning on Audio and Multimedia Data". Proceedings of the 27th ACM International Conference on Multimedia . ACM . pp. 2709–2710. doi : 10.1145/3343031.3350545 . ISBN 978-1-4503-6889-6 . S2CID 204837170 .
213. ^ "Stop tinkering, start measuring! Predictable experimental design of Neural Network experiments" . The Tensorflow Meter . Archived from the original on 18 April 2022 . Retrieved 10 March 2020 .
214. ^ Lee J, Xiao L, Schoenholz SS, Bahri Y, Novak R, Sohl-Dickstein J, et al. (2020). "Wide neural networks of any depth evolve as linear models under gradient descent". Journal of Statistical Mechanics: Theory and Experiment . 2020 (12): 124002. arXiv : 1902.06720 . Bibcode : 2020JSMTE2020l4002L . doi : 10.1088/1742-5468/abc62b . S2CID 62841516 .
215. ^ Arthur Jacot, Franck Gabriel, Clement Hongler (2018). Neural Tangent Kernel: Convergence and Generalization in Neural Networks (PDF) . 32nd Conference on Neural Information Processing Systems (NeurIPS 2018), Montreal, Canada. Archived (PDF) from the original on 22 June 2022 . Retrieved 4 June 2022 .
216. ^ Xu ZJ, Zhang Y, Xiao Y (2019). "Training Behavior of Deep Neural Network in Frequency Domain". In Gedeon T, Wong K, Lee M (eds.). Neural Information Processing . Lecture Notes in Computer Science. Vol. 11953. Springer, Cham. pp. 264–274. arXiv : 1807.01251 . doi : 10.1007/978-3-030-36708-4_22 . ISBN 978-3-030-36707-7 . S2CID 49562099 .
217. ^ Nasim Rahaman, Aristide Baratin, Devansh Arpit, Felix Draxler, Min Lin, Fred Hamprecht, et al. (2019). "On the Spectral Bias of Neural Networks" (PDF) . Proceedings of the 36th International Conference on Machine Learning . 97 : 5301–5310. arXiv : 1806.08734 . Archived (PDF) from the original on 22 October 2022 . Retrieved 4 June 2022 .
218. ^ Zhi-Qin John Xu, Yaoyu Zhang, Tao Luo, Yanyang Xiao, Zheng Ma (2020). "Frequency Principle: Fourier Analysis Sheds Light on Deep Neural Networks". Communications in Computational Physics . 28 (5): 1746–1767. arXiv : 1901.06523 . Bibcode : 2020CCoPh..28.1746X . doi : 10.4208/cicp.OA-2020-0085 . S2CID 58981616 .
219. ^ Tao Luo, Zheng Ma, Zhi-Qin John Xu, Yaoyu Zhang (2019). "Theory of the Frequency Principle for General Deep Neural Networks". arXiv : 1906.09235 [ cs.LG ].
220. ^ Xu ZJ, Zhou H (18 May 2021). "Deep Frequency Principle Towards Understanding Why Deeper Learning is Faster" . Proceedings of the AAAI Conference on Artificial Intelligence . 35 (12): 10541–10550. arXiv : 2007.14313 . doi : 10.1609/aaai.v35i12.17261 . ISSN 2374-3468 . S2CID 220831156 . Archived from the original on 5 October 2021 . Retrieved 5 October 2021 .
221. ^ Parisi GI, Kemker R, Part JL, Kanan C, Wermter S (1 May 2019). "Continual lifelong learning with neural networks: A review" . Neural Networks . 113 : 54–71. arXiv : 1802.07569 . doi : 10.1016/j.neunet.2019.01.012 . ISSN 0893-6080 . PMID 30780045 .
222. ^ Dean Pomerleau, "Knowledge-based Training of Artificial Neural Networks for Autonomous Robot Driving"
223. ^ Dewdney AK (1 April 1997). Yes, we have no neutrons: an eye-opening tour through the twists and turns of bad science . Wiley. p. 82. ISBN 978-0-471-10806-1 .
224. ^ NASA – Dryden Flight Research Center – News Room: News Releases: NASA NEURAL NETWORK PROJECT PASSES MILESTONE Archived 2 April 2010 at the Wayback Machine . Nasa.gov. Retrieved on 20 November 2013.
225. ^ "Roger Bridgman's defence of neural networks" . Archived from the original on 19 March 2012 . Retrieved 12 July 2010 .
226. ^ "Scaling Learning Algorithms towards {AI} - LISA - Publications - Aigaion 2.0" . www.iro.umontreal.ca .
227. ^ D. J. Felleman and D. C. Van Essen, " Distributed hierarchical processing in the primate cerebral cortex ," Cerebral Cortex , 1, pp. 1–47, 1991.
228. ^ J. Weng, " Natural and Artificial Intelligence: Introduction to Computational Brain-Mind ," BMI Press, ISBN 978-0-9858757-2-5 , 2012.
229. ^ a b Edwards C (25 June 2015). "Growing pains for deep learning". Communications of the ACM . 58 (7): 14–16. doi : 10.1145/2771283 . S2CID 11026540 .
230. ^ Cade Metz (18 May 2016). "Google Built Its Very Own Chips to Power Its AI Bots" . Wired . Archived from the original on 13 January 2018 . Retrieved 5 March 2017 .
231. ^ "Scaling Learning Algorithms towards AI" (PDF) . Archived (PDF) from the original on 12 August 2022 . Retrieved 6 July 2022 .
232. ^ Tahmasebi, Hezarkhani (2012). "A hybrid neural networks-fuzzy logic-genetic algorithm for grade estimation" . Computers & Geosciences . 42 : 18–27. Bibcode : 2012CG.....42...18T . doi : 10.1016/j.cageo.2012.02.004 . PMC 4268588 . PMID 25540468 .
233. ^ Sun and Bookman, 1990
234. ^ a b Norori N, Hu Q, Aellen FM, Faraci FD, Tzovara A (October 2021). "Addressing bias in big data and AI for health care: A call for open science" . Patterns . 2 (10): 100347. doi : 10.1016/j.patter.2021.100347 . PMC 8515002 . PMID 34693373 .
235. ^ a b Carina W (27 October 2022). "Failing at Face Value: The Effect of Biased Facial Recognition Technology on Racial Discrimination in Criminal Justice" . Scientific and Social Research . 4 (10): 29–40. doi : 10.26689/ssr.v4i10.4402 . ISSN 2661-4332 .
236. ^ a b Chang X (13 September 2023). "Gender Bias in Hiring: An Analysis of the Impact of Amazon's Recruiting Algorithm" . Advances in Economics, Management and Political Sciences . 23 (1): 134–140. doi : 10.54254/2754-1169/23/20230367 . ISSN 2754-1169 .
237. ^ Kortylewski A, Egger B, Schneider A, Gerig T, Morel-Forster A, Vetter T (June 2019). "Analyzing and Reducing the Damage of Dataset Bias to Face Recognition with Synthetic Data". 2019 IEEE/CVF Conference on Computer Vision and Pattern Recognition Workshops (CVPRW) (PDF) . IEEE. pp. 2261–2268. doi : 10.1109/cvprw.2019.00279 . ISBN 978-1-7281-2506-0 . S2CID 198183828 .
238. ^ a b c d e f Huang Y (2009). "Advances in Artificial Neural Networks – Methodological Development and Application" . Algorithms . 2 (3): 973–1007. doi : 10.3390/algor2030973 . ISSN 1999-4893 .
239. ^ a b c d e Kariri E, Louati H, Louati A, Masmoudi F (2023). "Exploring the Advancements and Future Research Directions of Artificial Neural Networks: A Text Mining Approach" . Applied Sciences . 13 (5): 3186. doi : 10.3390/app13053186 . ISSN 2076-3417 .
240. ^ a b Fui-Hoon Nah F, Zheng R, Cai J, Siau K, Chen L (3 July 2023). "Generative AI and ChatGPT: Applications, challenges, and AI-human collaboration" . Journal of Information Technology Case and Application Research . 25 (3): 277–304. doi : 10.1080/15228053.2023.2233814 . ISSN 1522-8053 .
241. ^ "DALL-E 2's Failures Are the Most Interesting Thing About It - IEEE Spectrum" . spectrum.ieee.org . Retrieved 9 December 2023 .
242. ^ Briot JP (January 2021). "From artificial neural networks to deep learning for music generation: history, concepts and trends" . Neural Computing and Applications . 33 (1): 39–65. doi : 10.1007/s00521-020-05399-0 . ISSN 0941-0643 .
243. ^ Chow PS (6 July 2020). "Ghost in the (Hollywood) machine: Emergent applications of artificial intelligence in the film industry". NECSUS_European Journal of Media Studies . doi : 10.25969/MEDIAREP/14307 . ISSN 2213-0217 .
244. ^ Yu X, He S, Gao Y, Yang J, Sha L, Zhang Y, et al. (June 2010). "Dynamic difficulty adjustment of game AI for video game Dead-End". The 3rd International Conference on Information Sciences and Interaction Sciences . IEEE. pp. 583–587. doi : 10.1109/icicis.2010.5534761 . ISBN 978-1-4244-7384-7 . S2CID 17555595 .
## Bibliography [ edit ]
* Bhadeshia H. K. D. H. (1999). "Neural Networks in Materials Science" (PDF) . ISIJ International . 39 (10): 966–979. doi : 10.2355/isijinternational.39.966 .
* Bishop CM (1995). Neural networks for pattern recognition . Clarendon Press. ISBN 978-0-19-853849-3 . OCLC 33101074 .
* Borgelt C (2003). Neuro-Fuzzy-Systeme: von den Grundlagen künstlicher Neuronaler Netze zur Kopplung mit Fuzzy-Systemen . Vieweg. ISBN 978-3-528-25265-6 . OCLC 76538146 .
* Cybenko G (2006). "Approximation by Superpositions of a Sigmoidal function" . In van Schuppen JH (ed.). Mathematics of Control, Signals, and Systems . Springer International. pp. 303–314. PDF
* Dewdney AK (1997). Yes, we have no neutrons: an eye-opening tour through the twists and turns of bad science . New York: Wiley. ISBN 978-0-471-10806-1 . OCLC 35558945 .
* Duda RO, Hart PE, Stork DG (2001). Pattern classification (2 ed.). Wiley. ISBN 978-0-471-05669-0 . OCLC 41347061 .
* Egmont-Petersen M, de Ridder D, Handels H (2002). "Image processing with neural networks – a review". Pattern Recognition . 35 (10): 2279–2301. CiteSeerX 10.1.1.21.5444 . doi : 10.1016/S0031-3203(01)00178-9 .
* Fahlman S, Lebiere C (1991). "The Cascade-Correlation Learning Architecture" (PDF) . Archived from the original (PDF) on 3 May 2013 . Retrieved 28 August 2006 .
* created for National Science Foundation , Contract Number EET-8716324, and Defense Advanced Research Projects Agency (DOD), ARPA Order No. 4976 under Contract F33615-87-C-1499.
* Gurney K (1997). An introduction to neural networks . UCL Press. ISBN 978-1-85728-673-1 . OCLC 37875698 .
* Haykin SS (1999). Neural networks: a comprehensive foundation . Prentice Hall. ISBN 978-0-13-273350-2 . OCLC 38908586 .
* Hertz J, Palmer RG, Krogh AS (1991). Introduction to the theory of neural computation . Addison-Wesley. ISBN 978-0-201-51560-2 . OCLC 21522159 .
* Information theory, inference, and learning algorithms . Cambridge University Press. 25 September 2003. Bibcode : 2003itil.book.....M . ISBN 978-0-521-64298-9 . OCLC 52377690 .
* Kruse R, Borgelt C, Klawonn F, Moewes C, Steinbrecher M, Held P (2013). Computational intelligence: a methodological introduction . Springer. ISBN 978-1-4471-5012-1 . OCLC 837524179 .
* Lawrence J (1994). Introduction to neural networks: design, theory and applications . California Scientific Software. ISBN 978-1-883157-00-5 . OCLC 32179420 .
* Masters T (1994). Signal and image processing with neural networks: a C++ sourcebook . J. Wiley. ISBN 978-0-471-04963-0 . OCLC 29877717 .
* Maurer H (2021). Cognitive science: integrative synchronization mechanisms in cognitive neuroarchitectures of the modern connectionism . CRC Press. doi : 10.1201/9781351043526 . ISBN 978-1-351-04352-6 . S2CID 242963768 .
* Ripley BD (2007). Pattern Recognition and Neural Networks . Cambridge University Press. ISBN 978-0-521-71770-0 .
* Siegelmann H, Sontag ED (1994). "Analog computation via neural networks" . Theoretical Computer Science . 131 (2): 331–360. doi : 10.1016/0304-3975(94)90178-3 . S2CID 2456483 .
* Smith M (1993). Neural networks for statistical modeling . Van Nostrand Reinhold. ISBN 978-0-442-01310-3 . OCLC 27145760 .
* Wasserman PD (1993). Advanced methods in neural computing . Van Nostrand Reinhold. ISBN 978-0-442-00461-3 . OCLC 27429729 .
* Wilson H (2018). Artificial intelligence . Grey House Publishing. ISBN 978-1-68217-867-6 .
* v
* t
* e
Complex systems
---
Background |
* Emergence
* Self-organization
Collective
behavior |
* Social dynamics
* Collective intelligence
* Collective action
* Collective consciousness
* Self-organized criticality
* Herd mentality
* Phase transition
* Agent-based modelling
* Synchronization
* Ant colony optimization
* Particle swarm optimization
* Swarm behaviour
Evolution and
adaptation |
* Artificial neural network
* Evolutionary computation
* Genetic algorithms
* Genetic programming
* Artificial life
* Machine learning
* Evolutionary developmental biology
* Artificial intelligence
* Evolutionary robotics
* Evolvability
Game theory |
* Prisoner's dilemma
* Rational choice theory
* Bounded rationality
* Evolutionary game theory
Networks |
* Social network analysis
* Small-world networks
* Centrality
* Motifs
* Graph theory
* Scaling
* Robustness
* Systems biology
* Dynamic networks
* Adaptive networks
Nonlinear dynamics |
* Time series analysis
* Ordinary differential equations
* Phase space
* Attractor
* Population dynamics
* Chaos
* Multistability
* Bifurcation
* Coupled map lattices
Pattern formation |
* Reaction-diffusion systems
* Partial differential equations
* Dissipative structures
* Percolation
* Cellular automata
* Spatial ecology
* Self-replication
* Geomorphology
Systems theory |
* Homeostasis
* Operationalization
* Feedback
* Self-reference
* Goal-oriented
* System dynamics
* Sensemaking
* Entropy
* Cybernetics
* Autopoiesis
* Information theory
* Computation theory
* v
* t
* e
Control theory
---
Branches |
* Adaptive control
* Control Theory
* Digital control
* Energy-shaping control
* Fuzzy control
* Hybrid control
* Intelligent control
* Model predictive control
* Multivariable control
* Neural control
* Nonlinear control
* Optimal control
* Real-time control
* Robust control
* Stochastic control
System Properties |
* Bode plot
* Block diagram
* Closed-loop transfer function
* Controllability
* Fourier transform
* Frequency response
* Laplace transform
* Negative feedback
* Observability
* Performance
* Positive feedback
* Root Locus Method
* Servomechanism
* Signal-flow graph
* State space representation
* Stability Theory
* Steady State Analysis & design
* System Dynamics
* Transfer function
Digital Control |
* Discrete-time signal
* Digital signal processing
* Quantization
* Real Time Software
* Sampled Data
* System identification
* Z Transform
Advanced Techniques |
* Artificial neural network
* Coefficient diagram method
* Control reconfiguration
* Distributed parameter systems
* Fractional-order control
* Fuzzy logic
* H-infinity loop-shaping
* Hankel singular value
* Kalman filter
* Krener's theorem
* Least squares
* Lyapunov stability
* Minor loop feedback
* Perceptual control theory
* State observer
* Vector control
Controllers |
* Embedded controller
* Closed-loop controller
* Lead-lag compensator
* Numerical control
* PID controller
* Programmable logic controller
Control Applications |
* Automation and Remote Control
* Distributed Control System
* Electric motors
* Industrial Control Systems
* Mechatronics
* Motion control
* Process Control
* Robotics
* Supervisory control (SCADA)
* v
* t
* e
Differentiable computing
---
General |
* Differentiable programming
* Information geometry
* Statistical manifold
* Automatic differentiation
* Neuromorphic engineering
* Pattern recognition
* Tensor calculus
* Computational learning theory
* Inductive bias
Concepts |
* Gradient descent
* SGD
* Clustering
* Regression
* Overfitting
* Hallucination
* Adversary
* Attention
* Convolution
* Loss functions
* Backpropagation
* Batchnorm
* Activation
* Softmax
* Sigmoid
* Rectifier
* Regularization
* Datasets
* Augmentation
* Diffusion
* Autoregression
Applications |
* Machine learning
* In-context learning
* Artificial neural network
* Deep learning
* Scientific computing
* Artificial Intelligence
* Language model
* Large language model
Hardware |
* IPU
* TPU
* VPU
* Memristor
* SpiNNaker
Software libraries |
* TensorFlow
* PyTorch
* Keras
* Theano
* JAX
* Flux.jl
* MindSpore
Implementations | | Audio–visual |
* AlexNet
* WaveNet
* Human image synthesis
* HWR
* OCR
* Speech synthesis
* Speech recognition
* Facial recognition
* AlphaFold
* Text-to-image models
* DALL-E
* Midjourney
* Stable Diffusion
* Text-to-video models
* Sora
* VideoPoet
* Whisper
---|---
Verbal |
* Word2vec
* Seq2seq
* BERT
* Gemini
* LaMDA
* Bard
* NMT
* Project Debater
* IBM Watson
* IBM Watsonx
* Granite
* GPT-1
* GPT-2
* GPT-3
* GPT-4
* ChatGPT
* GPT-J
* Chinchilla AI
* PaLM
* BLOOM
* LLaMA
* PanGu-Σ
Decisional |
* AlphaGo
* AlphaZero
* Q-learning
* SARSA
* OpenAI Five
* Self-driving car
* MuZero
* Action selection
* Auto-GPT
* Robot control
People |
* Yoshua Bengio
* Alex Graves
* Ian Goodfellow
* Stephen Grossberg
* Demis Hassabis
* Geoffrey Hinton
* Yann LeCun
* Fei-Fei Li
* Andrew Ng
* Jürgen Schmidhuber
* David Silver
* Ilya Sutskever
Organizations |
* Anthropic
* EleutherAI
* Google DeepMind
* Hugging Face
* OpenAI
* Meta AI
* Mila
* MIT CSAIL
* Huawei
Architectures |
* Neural Turing machine
* Differentiable neural computer
* Transformer
* Recurrent neural network (RNN)
* Long short-term memory (LSTM)
* Gated recurrent unit (GRU)
* Echo state network
* Multilayer perceptron (MLP)
* Convolutional neural network
* Residual neural network
* Mamba
* Autoencoder
* Variational autoencoder (VAE)
* Generative adversarial network (GAN)
* Graph neural network
* Portals
* Computer programming
* Technology
* Categories
* Artificial neural networks
* Machine learning
* v
* t
* e
Neuroscience
---
* Outline
* History
Basic
science |
* Behavioral epigenetics
* Behavioral genetics
* Brain mapping
* Brain-reading
* Cellular neuroscience
* Computational neuroscience
* Connectomics
* Imaging genetics
* Integrative neuroscience
* Molecular neuroscience
* Neural decoding
* Neural engineering
* Neuroanatomy
* Neurobiology
* Neurochemistry
* Neuroendocrinology
* Neurogenetics
* Neuroinformatics
* Neurometrics
* Neuromorphology
* Neurophysics
* Neurophysiology
* Systems neuroscience
|
Clinical
neuroscience |
* Behavioral neurology
* Clinical neurophysiology
* Epileptology
* Neurocardiology
* Neuroepidemiology
* Neurogastroenterology
* Neuroimmunology
* Neurointensive care
* Neurology
* Neuro-oncology
* Neuro-ophthalmology
* Neuropathology
* Neuropharmacology
* Neuroprosthetics
* Neuropsychiatry
* Neuroradiology
* Neurorehabilitation
* Neurosurgery
* Neurotology
* Neurovirology
* Nutritional neuroscience
* Psychiatry
Cognitive
neuroscience |
* Affective neuroscience
* Behavioral neuroscience
* Chronobiology
* Molecular cellular cognition
* Motor control
* Neurolinguistics
* Neuropsychology
* Sensory neuroscience
* Social cognitive neuroscience
Interdisciplinary
fields |
* Consumer neuroscience
* Cultural neuroscience
* Educational neuroscience
* Evolutionary neuroscience
* Global neurosurgery
* Neuroanthropology
* Neural engineering
* Neurobiotics
* Neurocriminology
* Neuroeconomics
* Neuroepistemology
* Neuroesthetics
* Neuroethics
* Neuroethology
* Neurohistory
* Neurolaw
* Neuromarketing
* Neuromorphic engineering
* Neurophenomenology
* Neurophilosophy
* Neuropolitics
* Neurorobotics
* Neurotheology
* Paleoneurobiology
* Social neuroscience
Concepts |
* Brain–computer interface
* Development of the nervous system
* Neural network (artificial)
* Neural network (biological)
* Detection theory
* Intraoperative neurophysiological monitoring
* Neurochip
* Neurodegenerative disease
* Neurodevelopmental disorder
* Neurodiversity
* Neurogenesis
* Neuroimaging
* Neuroimmune system
* Neuromanagement
* Neuromodulation
* Neuroplasticity
* Neurotechnology
* Neurotoxin
* Category
* Commons
* v
* t
* e
Self-driving cars , self-driving vehicles and enabling technologies
---
Overview and
context |
* History of self-driving cars
* Impact of self-driving cars
* Intelligent transportation system
* Context-aware pervasive systems
* Mobile computing
* Smart, connected products
* Ubiquitous computing
* Ambient intelligence
* Internet of things
SAE Levels | | Human driver monitors
the driving environment
(Levels 0,1,2) |
* Lane departure warning system
* Automatic parking
* Automated emergency braking system
* Collision avoidance system
* Cruise control
* Adaptive cruise control
* Advanced driver-assistance system
* Driver drowsiness detection
* Intelligent speed adaptation
* Blind spot monitor
---|---
System monitors
the driving environment
(Levels 3,4,5) |
* Automated Lane Keeping Systems
* Vehicular ad hoc network (V2V)
* Connected car
* Automotive navigation system
Vehicles | | Cars |
* VaMP (1994)
* Spirit of Berlin (2007)
* General Motors EN-V (2010)
* MadeInGermany (2011)
* Waymo , formerly Google Car (2012)
* Tesla Model S with Autopilot (2015)
* LUTZ Pathfinder (2015)
* Yandex self-driving car (2017)
* Honda Legend (2021)
---|---
Buses and commercial
vehicles |
* Automated guideway transit
* CAVForth
* ParkShuttle
* Navia shuttle
* NuTonomy taxi
* Freightliner Inspiration
* Driverless tractor
* Self-driving truck
* Mobility as a service
Regulation |
* Legislation
* IEEE 802.11p
* Safe speed automotive common law
* Automated lane keeping system (unece regulation 157)
* Regulation (EU) 2019/2144
Liability | Self-driving car liability
Enabling
technologies |
* Radar
* Laser
* LIDAR
* Artificial neural network
* Computer stereo vision
* Image recognition
* Dedicated short-range communications
* Real-time Control System
* rFpro
* Eye tracking
* Radio-frequency identification
* Automotive navigation system
Organizations,
Projects &
People | | Organizations,
projects
and events |
* American Center for Mobility
* DAVI
* European Land-Robot Trial
* Navlab
* DARPA Grand Challenge
* VisLab Intercontinental Autonomous Challenge
* Eureka Prometheus Project
* IEEE Intelligent Transportation Systems Society
---|---
People |
* Harold Goddijn
* Alberto Broggi
* Anthony Levandowski
Authority control databases : National |
* Germany
* Israel
* United States
* Japan
* Czech Republic
---|---
Retrieved from "
https://en.wikipedia.org/w/index.php?title=Neural_network_(machine_learning)&oldid=1221323260
"
Categories :
* Computational statistics
* Artificial neural networks
* Classification algorithms
* Computational neuroscience
* Market research
* Mathematical psychology
* Mathematical and quantitative methods (economics)
* Bioinspiration
Hidden categories:
* CS1 Finnish-language sources (fi)
* Webarchive template wayback links
* All articles with dead external links
* Articles with dead external links from March 2024
* Articles with permanently dead external links
* CS1 German-language sources (de)
* All articles with incomplete citations
* Articles with incomplete citations from June 2022
* CS1: long volume value
* Articles with short description
* Short description matches Wikidata
* Use dmy dates from March 2023
* Pages using multiple image with auto scaled images
* Wikipedia articles needing clarification from April 2017
* All Wikipedia articles needing clarification
* Articles lacking in-text citations from August 2019
* All articles lacking in-text citations
* All articles with unsourced statements
* Articles with unsourced statements from June 2022
* Articles with unsourced statements from July 2019
* Articles with unsourced statements from July 2023
* All articles with failed verification
* Articles with failed verification from May 2023
* Articles with unsourced statements from January 2023
* Articles with specifically marked weasel-worded phrases from January 2023
* Articles with hAudio microformats
* Spoken articles
* Articles with GND identifiers
* Articles with J9U identifiers
* Articles with LCCN identifiers
* Articles with NDL identifiers
* Articles with NKC identifiers
* This page was last edited on 29 April 2024, at 07:01 (UTC) .
* Text is available under the Creative Commons Attribution-ShareAlike License 4.0 ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy . Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. , a non-profit organization.
* Privacy policy
* About Wikipedia
* Disclaimers
* Contact Wikipedia
* Code of Conduct
* Developers
* Statistics
* Cookie statement
* Mobile view
* *
* Toggle limited content width
*[
v
]: View this template
*[
t
]: Discuss this template
*[
e
]: Edit this template
*[
v
]: View this template
*[
t
]: Discuss this template
*[
e
]: Edit this template
| biology | 4911750 | https://sv.wikipedia.org/wiki/Stanley%E2%80%93Reisnerring | Stanley–Reisnerring | Inom matematiken är en Stanley–Reisnerring ett kvot av en polynomalgebra över en kropp med ett kvadratfritt monomideal. Konstruktionen av Stanley–Reisnerringar är ett grundläggande verktyg i algebraisk kombinatorik och kombinatorisk kommutativ algebra. Dears egenskaper studerades av Richard Stanley, Melvin Hochster och Gerald Reisner under det tidiga 1970-talet.
Källor
Melvin Hochster, Cohen-Macaulay rings, combinatorics, and simplicial complexes. Ring theory, II (Proc. Second Conf., Univ. Oklahoma, Norman, Okla., 1975), pp. 171–223. Lecture Notes in Pure and Appl. Math., Vol. 26, Dekker, New York, 1977
Fotnoter
Vidare läsning
Externa länkar
Algebraisk kombinatorik
Kommutativ algebra | swedish | 1.006147 |
neurons_learn/neurons.txt | Donate
* Home
* Basic Neuroscience
* Neurons Transmit Messages In The Brain
# Neurons Transmit Messages In The Brain
Neurons are the cells that pass chemical and electrical signals along the
pathways in the brain. They come in many shapes and sizes. Their shapes and
connections help them carry out specialized functions, such as storing
memories or controlling muscles.
## Neurons Communicate via the Synapse
Information from one neuron flows to another neuron across a small gap called
a synapse (SIN-aps). At the synapse, electrical signals are translated into
chemical signals in order to cross the gap. Once on the other side, the signal
becomes electrical again.
One sending neuron can connect to several receiving neurons, and one receiving
neuron can connect to several sending neurons.
Visit Teach.Genetics
Sign up for our email announcements
Cite this page Disclaimer Permissions Policy Privacy Policy
Copyright © University of Utah GSLC
APA format:
Genetic Science Learning Center. (2015, June 30) Neurons Transmit Messages In
The Brain. Retrieved April 26, 2024, from
https://learn.genetics.utah.edu/content/neuroscience/neurons
CSE format:
Neurons Transmit Messages In The Brain [Internet]. Salt Lake City (UT):
Genetic Science Learning Center; 2015 [cited 2024 Apr 26] Available from
https://learn.genetics.utah.edu/content/neuroscience/neurons
Chicago format:
Genetic Science Learning Center. "Neurons Transmit Messages In The Brain."
Learn.Genetics. June 30, 2015. Accessed April 26, 2024.
https://learn.genetics.utah.edu/content/neuroscience/neurons.
| biology | 1332 | https://sv.wikipedia.org/wiki/Neurovetenskap | Neurovetenskap | Neurovetenskap är en sedan 1970-talet använd samlingsbenämning för all vetenskap som sysslar med nervsystemets uppbyggnad och funktioner. Neuroforskare och neurologer studerar neurovetenskap.
Historik
Abulcasis, Averroes, Avenzoar och Maimonides, medeltida läkare och vetenskapsmän i det muslimska området, beskrev ett flertal medicinska problem relaterade till hjärnan.
Modern neurovetenskap
Under 1900-talets senare del har neurovetenskapen utvecklats kraftigt, framförallt beroende på framsteg inom molekylärbiologi, elektrofysiologi och datorbaserad neurovetenskap.
Se även
Neuroanatomi
Neurofysiologi
Neuroimaging
Neurokirurgi
Neurologi
Neuropatologi
Neuropsykiatri
Neuropsykologi
Neurokemi
Externa länkar | swedish | 0.558498 |
neurons_learn/arup-neuron.txt | Search for projects, services, people and more
Please enter at least 2 characters
Arup
* Markets
* Active travel
* Commercial property
* Highways
* Residential property
* Advanced manufacturing
* Data centres and technology
* Hotels and leisure
* Retail
* Arts and culture
* Education
* International development
* Scientific research facilities
* Aviation
* Energy
* Maritime
* Sport
* Cities
* Healthcare
* Rail
* Water
* Services
####
* Advisory Services
* Buildings
* Digital
* Climate & sustainability
* Infrastructure
* Planning
* Technical Consulting
* Strategy and insights
* Sustainable Development Advisory
* Assets and operations
* Finance and economics
* People and organisations
* Programmes and projects
* Accessible environments
* Architecture
* Building design
* Building envelope and facade design
* Building Information Modelling
* Building physics
* Building retrofit
* Building services engineering
* Commissioning and building performance evaluation
* Electrical engineering
* Facilities management
* Fire engineering
* Mechanical engineering
* Public health, hydraulics and plumbing
* Smart buildings
* Structural engineering
* Sustainable building design
* Digital asset management
* Digital consulting
* Digital for sustainable development
* Digital design
* Emerging technologies
* Data in the natural and built environment
* See all digital products and services
* Adaptation and resilience
* Circular economy
* Decarbonisation
* Integrated nature solutions
* Social value and equity
* Strategy and reporting
* Sustainability consulting
* Airport planning
* Bridge engineering
* Civil engineering
* Infrastructure design
* Rail engineering
* Sustainable infrastructure
* Tunnel design
* Waste management strategies
* Waste to energy solutions
* Water engineering
* Economic planning
* Environmental consulting
* Flood risk management
* Landscape architecture
* Masterplanning
* Planning policy advice
* Resilience security and risk
* Smart cities
* Town planning
* Transport consulting
* Acoustic consulting
* Audio visual and multimedia
* Fluid dynamics
* Geospatial services
* Geotechnics
* Hydrogeology
* ICT infrastructure design
* Lighting design
* Materials
* Process engineering
* Product design
* Quantity surveying
* Seismic design
* Software products
* Specialist technology, analytics and research
* Technology operations and project management
* Theatre consulting
* Vibration engineering
* Wind engineering
* Projects
* Futures
* Our Firm
#### We shape a better world
Sir Ove Arup's Key Speech Learn more about our firm
####
* Values
* History
* Mission
* Leadership and governance
* Annual report
####
* Arup University
* Community engagement
* Partnerships
* Ventures
* Careers
#### Join us to shape a better world
Careers at Arup
* Search all jobs
* Discover life at Arup
* Meet our brilliant minds
* Explore our locations
* Early careers
* Graduates
* Internships
* Apprenticeships
* Offices
* Australia
* Brunei
* Cambodia
* Canada
* Colombia
* Denmark
* Germany
* Greater China
* India
* Indonesia
* Ireland
* Italy
* Japan
* Kenya
* Malaysia
* Mauritius
* Netherlands
* New Zealand
* Nigeria
* Philippines
* Poland
* Sabah
* Serbia
* Singapore
* South Africa
* South Korea
* Spain
* Thailand
* Türkiye
* United Arab Emirates
* United Kingdom
* United States of America
* Vietnam
* Zimbabwe
* Contact
* Search
Close
Back
* * Markets
* ### Markets See all
* Active travel
* Advanced manufacturing
* Arts and culture
* Aviation
* Cities
* Commercial property
* Data centres and technology
* Education
* Energy
* Healthcare
* Highways
* Hotels and leisure
* International development
* Maritime
* Rail
* Residential property
* Retail
* Scientific research facilities
* Sport
* Water
* Services
* ### Services See all
####
##### Advisory Services
* Strategy and insights
* Sustainable Development Advisory
* Assets and operations
* Finance and economics
* People and organisations
* Programmes and projects
##### Buildings
* Accessible environments
* Architecture
* Building design
* Building envelope and facade design
* Building Information Modelling
* Building physics
* Building retrofit
* Building services engineering
* Commissioning and building performance evaluation
* Electrical engineering
* Facilities management
* Fire engineering
* Mechanical engineering
* Public health, hydraulics and plumbing
* Smart buildings
* Structural engineering
* Sustainable building design
##### Digital
* Digital asset management
* Digital consulting
* Digital for sustainable development
* Digital design
* Emerging technologies
* Data in the natural and built environment
* See all digital products and services
##### Climate & sustainability
* Adaptation and resilience
* Circular economy
* Decarbonisation
* Integrated nature solutions
* Social value and equity
* Strategy and reporting
* Sustainability consulting
##### Infrastructure
* Airport planning
* Bridge engineering
* Civil engineering
* Infrastructure design
* Rail engineering
* Sustainable infrastructure
* Tunnel design
* Waste management strategies
* Waste to energy solutions
* Water engineering
##### Planning
* Economic planning
* Environmental consulting
* Flood risk management
* Landscape architecture
* Masterplanning
* Planning policy advice
* Resilience security and risk
* Smart cities
* Town planning
* Transport consulting
##### Technical Consulting
* Acoustic consulting
* Audio visual and multimedia
* Fluid dynamics
* Geospatial services
* Geotechnics
* Hydrogeology
* ICT infrastructure design
* Lighting design
* Materials
* Process engineering
* Product design
* Quantity surveying
* Seismic design
* Software products
* Specialist technology, analytics and research
* Technology operations and project management
* Theatre consulting
* Vibration engineering
* Wind engineering
* Projects
* Futures
* Our Firm
* ### Our Firm See all
####
* Values
* History
* Mission
* Leadership and governance
* Annual report
####
* Arup University
* Community engagement
* Partnerships
* Ventures
Sir Ove Arup's Key Speech Learn more about our firm
* Careers
* ### Careers See all
* Search all jobs
* Discover life at Arup
* Meet our brilliant minds
* Explore our locations
#### Early careers
* Graduates
* Internships
* Apprenticeships
* Offices
* ### Offices See all
* Australia
* Brunei
* Cambodia
* Canada
* Colombia
* Denmark
* Germany
* Greater China
* India
* Indonesia
* Ireland
* Italy
* Japan
* Kenya
* Malaysia
* Mauritius
* Netherlands
* New Zealand
* Nigeria
* Philippines
* Poland
* Sabah
* Serbia
* Singapore
* South Africa
* South Korea
* Spain
* Thailand
* Türkiye
* United Arab Emirates
* United Kingdom
* United States of America
* Vietnam
* Zimbabwe
* Contact
Search
Get in touch
Sorry, it looks like there are no results for
Suggestions
View all results for
Select language:
EN
Select language:
English
* Simplified Chinese
* Traditional Chinese
; ;
# Arup Neuron
Translating smart buildings data into smarter insights and better decisions
Translating smart buildings data into smarter insights and better decisions
Share
Icons/Social/Facebook Created with Sketch. Icons/Social/LinkedIn Created
with Sketch. Icons/Social/Twitter Created with Sketch. Icons/Social/More
Created with Sketch.
Arup Neuron
Talk to Mark Chen about this service
#### Talk to Mark Chen about this service
Get in touch
##### Get in touch
Mark Chen Associate
[email protected] 852 2528 3031 Hong Kong, local time - 2:29 PM
If buildings had a ‘brain’, monitoring their systems and responding in real
time, how much more secure, comfortable and efficient could they become? We
are answering that question with Neuron, using artificial intelligence to
make our buildings, districts and cities healthier, more sustainable places to
live and work.
Neuron is an app that integrates our insights into the built environment with
emerging digital technologies into a single platform. It uses 5G and the
Internet of Things to gather real-time ‘sense data’ from equipment and
systems. It uses Building Information Modelling (BIM) to display these
complex data sets through a cloud-based, centralised management console.
Neuron’s ‘brain’ uses artificial intelligence and machine learning to analyse,
optimise and automate operations.
To view this video, you must enable cookies.
Featured service
### Connecting the physical and digital worlds
Digital twins are helping to connect the physical and digital worlds together.
Our service, as consultants and technologists, is to develop a twin that
connects disparate information sources, building a digital twin that generates
valuable intelligence every day.
* * *
Learn more about service
Neuron unlocks smarter, data-driven decision making: for facility managers;
for building owners; for city authorities. We have created four applications
that put them in control of the energy they use, the health and well-being
they provide and the carbon emissions they produce:
1. Neuron Building
2. Neuron Health
3. Neuron Carbon
4. Neuron City
The insights they create are informing the way a new generation of smart
buildings and infrastructure are designed, constructed, managed and
maintained.
## Neuron Building: smart buildings, smarter decisions
Heating, ventilation and air conditioning (HVAC) systems give us year-round
comfort but are huge (and costly) consumers of energy. The data traditional
building automation and control systems generate has allowed operators to
monitor and react to changes in these systems. Real efficiency, however, comes
from the ability to anticipate, not just record and respond. Neuron Energy is
an app that turns this data into predictive control.
Through analyzing historical data, machine learning models uncover hidden
patterns and give estimation on energy usage for better planning in advance.
Arup Neuron’s trend analysis feature allows forecasting of energy demand to
better match cooling loads – the rate at which heat is removed from an
environment - to occupancy. Discovering dips in equipment performance curves
allows for early fault detection and preventative maintenance. Neuron’s self-
learning abilities mean it continually refines and improves its forecasts,
translating that learning into the energy efficiency of the systems it
controls.
### One Taikoo Place: Hong Kong's first AI-enabled building
One Taikoo Place is Hong Kong’s first AI-enabled, data-driven smart building.
Neuron’s cooling load predictions are within 5% of actual use, helping
developer Swire Properties successfully reduce energy use by 15%.
Learn more about our work
### One Taikoo Place: Hong Kong's first AI-enabled building
One Taikoo Place is Hong Kong’s first AI-enabled, data-driven smart building.
Neuron’s cooling load predictions are within 5% of actual use, helping
developer Swire Properties successfully reduce energy use by 15%.
Learn more about our work
## Neuron Health: healthier buildings, healthier rentals
Air quality makes the difference between so-called ‘sick’ buildings and
healthy ones. It not only affects the health of the individuals working in a
building. As companies increasingly prioritise the well-being of their people,
healthier buildings also translate into healthier rentals.
Neuron Health monitors temperature, humidity and levels of pathogens in the
air, identifying the correlations between indoor air quality and occupants’
health. Its predictive modelling gives building operators visibility of the
risks and identifies measures to mitigate them.
### Digital asset management for Beijing's iconic Water Cube
Implemented in Beijing's Water Cube building, Neuron facilitates the
digitalisation of venue facility management. We helped develop a smart
platform incorporating BIM, IoT and analytics for better asset management,
while contributing to a digital transformation model that helps optimise the
operations of future sports venues.
### Digital asset management for Beijing's iconic Water Cube
Implemented in Beijing's Water Cube building, Neuron facilitates the
digitalisation of venue facility management. We helped develop a smart
platform incorporating BIM, IoT and analytics for better asset management,
while contributing to a digital transformation model that helps optimise the
operations of future sports venues.
### AI-powered health screening tool
During the post-COVID-19 transition back to normality, we developed a new
feature for Neuron to identify those with a high temperature – one of the
first symptoms of the disease – in public or commercial environments.
We added a thermal imaging camera, which can measure forehead temperature
quickly and efficiently. The system can identify individuals with an elevated
body temperature and send that person to a separate queue for further
screening by a designated employee with a hand-held temperature scanner.
Download thermal imaging camera brochure
## Neuron Carbon: intelligent sustainability
Carbon emissions cost. In environmental impact and in energy bills. Neuron
Carbon is providing an intelligent way to reduce those costs. It allows
building operators to benchmark their resource management performance.
Neuron captures a complete record of emissions from the whole ecosystem of a
building. From direct, onsite emissions such as generators and cooling systems
to company cars, purchased energy, water, material and waste recycling. The
analysis Neuron’s algorithms provides helps set targets and implementation
plans, reducing carbon and providing an evidence base for carbon credits.
## Neuron City: from smart buildings to smart cities
The insights Neuron’s digital platform creates are not limited to individual
buildings. Asset owners can monitor, control and compare performance across
their whole campus or portfolio. With Neuron City, we are working with
authorities to bring that same level of insight and control to entire city
networks.
### Predicting responses
Meteorology can give us advanced warning of events like a typhoon, but how can
we predict how a city in its path will respond?
Working with Hong Kong’s electrical and mechanical services department, Neuron
City is integrating the government’s Internet of Things with a Geographic
Information System to visualise the whole city’s performance. The video wall
in the department’s control room monitors the real time situation,
anticipating how a typhoon may affect city infrastructure such as traffic
lights and helping authorities plan their response.
## Awards
* Hong Kong ICT Awards 2020: Smart Business Award (Big Data and Open Data Application) – Gold Award
* Construction Industry Council Celebration of BIM Achievement 2020 – BIM Projects 2020
* HKIE Innovation Award 2020 – Certificate of Merit in Category II – An Innovative Application of Engineering Theories
* The Energy Awards 2021 – Digital innovation of the year: Monitoring systems – Winner and Buildings Technology Innovation of the Year – Winner
* 2021 WITSA Global ICT Excellence Awards – Smart Cities Award (Private Sector/NGO) – Award Winner
* The 20th Asia Pacific Information and Communications Technology Alliance (APICTA) Awards – Technology category (Big Data) – Winner and Industrial category (General) – Merit
* IET Young Professionals Exhibition and Competition 2021 – Open Section – Champion and HK Electric Best Innovation Award – Winner
* ASHRAE Hong Kong Chapter Technology Award 2021 – Winner
* Chartered Institution of Building Services Engineers (CIBSE) Hong Kong Awards 2021 – COVID-19 Achievement Award
For more details, visit Neuron Digital
### Discover more
Learn how we're using digital to help clients better manage their assets
Icons/Social/Facebook Created with Sketch. Icons/Social/LinkedIn Created
with Sketch. Icons/Social/Twitter Created with Sketch. Icons/Social/More
Created with Sketch.
Arup
* * *
* Careers
* Get in touch
* News and events
* twitter
* linkedin
* facebook
* instagram
* rss
* * *
© Arup 2024 All rights reserved
* Our policies
* Cookies
* Legal
* Modern Slavery
* Governance
© Arup 2024. All rights reserved
| biology | 322543 | https://da.wikipedia.org/wiki/Information%20Engineering | Information Engineering | Information Engineering (IE) eller Information Engineering Methodology (IEM) i softwareudvikling er en tilgang til design og udvikling af informationssystemer.
Overblik
Information Engineering metodik er en arkitektonisk tilgang til planlægning, analyse og implementering af applikationer indenfor en virksomhed. Hensigten er at gøre virksomheden i stand til at forbedre styringen af dets ressourcer, heriblandt dets kapital, ansatte og informationssystemer, for at opnå dens mål. Det er defineret som: "An integrated and evolutionary set of tasks and techniques that enhance business communication throughout an enterprise enabling it to develop people, procedures and systems to achieve its vision".
Information Engineering har mange formål, disse inkluderer organisationsplanlægning, softwareudvikling, informationssystem planlægning og omarbejdelse af software.
Litteratur
John Hares (1992). "Information Engineering for the Advanced Practitioner", Wiley.
Clive Finkelstein (1989). An Introduction to Information Engineering : From Strategic Planning to Information Systems. Sydney: Addison-Wesley.
Ian Macdonald (1986). "Information Engineering". in: Information Systems Design Methodologies. T.W. Olle et al (ed.). North-Holland.
Ian Macdonald (1988). "Automating the Information Engineering Methodology with the Information Engineering Facility". In: Computerized Assistance during the Information Systems Life Cycle. T.W. Olle et al (ed.). North-Holland.
James Martin and Clive Finkelstein. (1981). Information Engineering. Technical Report (2 volumes), Savant Institute, Carnforth, Lancs, UK.
James Martin (1989). Information Engineering. (3 volumes), Prentice-Hall Inc.
Eksterne henvisninger
The Complex Method IEM
Rapid Application Development
Training Information Engineering Hogeschool Utrecht, Netherlands (Dutch)
Study of Information Engineering at Hogeschool van Amsterdam in Almere(Netherlands) (Dutch)
Study of Information Engineering in Hamburg (Bachelor and Master)
Systemudvikling | danish | 0.635962 |
neurons_learn/explained-neural-networks-deep-learning-0414.txt | Skip to content ↓
Massachusetts Institute of Technology
MIT Top Menu ↓
* Education
* Research
* Innovation
* Admissions + Aid
* Campus Life
* News
* Alumni
* About MIT
* More ↓
Search MIT
Search websites, locations, and people
See More Results
Suggestions or feedback?
## MIT News | Massachusetts Institute of Technology
Subscribe to MIT News newsletter
Browse
Enter keywords to search for news articles: Submit
## Browse By
### Topics
View All →
Explore:
* Machine learning
* Social justice
* Startups
* Black holes
* Classes and programs
### Departments
View All →
Explore:
* Aeronautics and Astronautics
* Brain and Cognitive Sciences
* Architecture
* Political Science
* Mechanical Engineering
### Centers, Labs, & Programs
View All →
Explore:
* Abdul Latif Jameel Poverty Action Lab (J-PAL)
* Picower Institute for Learning and Memory
* Media Lab
* Lincoln Laboratory
### Schools
* School of Architecture + Planning
* School of Engineering
* School of Humanities, Arts, and Social Sciences
* Sloan School of Management
* School of Science
* MIT Schwarzman College of Computing
View all news coverage of MIT in the media →
Listen to audio content from MIT News →
Subscribe to MIT newsletter →
Close
#### Breadcrumb
1. MIT News
2. Explained: Neural networks
# Explained: Neural networks
Ballyhooed artificial-intelligence technique known as “deep learning” revives
70-year-old idea.
Larry Hardesty | MIT News Office
Publication Date :
April 14, 2017
Press Inquiries
### Press Contact :
Abby Abazorius
Email: [email protected]
Phone: 617-253-2709
MIT News Office
### Media Download
↓ Download Image
Caption : Most applications of deep learning use “convolutional” neural
networks, in which the nodes of each layer are clustered, the clusters
overlap, and each cluster feeds data to multiple nodes (orange and green) of
the next layer.
Credits : Image: Jose-Luis Olivares/MIT
#### *Terms of Use:
Images for download on the MIT News office website are made available to non-
commercial entities, press and the general public under a Creative Commons
Attribution Non-Commercial No Derivatives license . You may not alter the
images provided, other than to crop them to size. A credit line must be used
when reproducing images; if one is not provided below, credit the images to
"MIT."
Close
Caption :
Most applications of deep learning use “convolutional” neural networks, in
which the nodes of each layer are clustered, the clusters overlap, and each
cluster feeds data to multiple nodes (orange and green) of the next layer.
Credits :
Image: Jose-Luis Olivares/MIT
Previous image Next image
In the past 10 years, the best-performing artificial-intelligence systems —
such as the speech recognizers on smartphones or Google’s latest automatic
translator — have resulted from a technique called “deep learning.”
Deep learning is in fact a new name for an approach to artificial intelligence
called neural networks, which have been going in and out of fashion for more
than 70 years. Neural networks were first proposed in 1944 by Warren
McCullough and Walter Pitts, two University of Chicago researchers who moved
to MIT in 1952 as founding members of what’s sometimes called the first
cognitive science department.
Neural nets were a major area of research in both neuroscience and computer
science until 1969, when, according to computer science lore, they were killed
off by the MIT mathematicians Marvin Minsky and Seymour Papert, who a year
later would become co-directors of the new MIT Artificial Intelligence
Laboratory.
The technique then enjoyed a resurgence in the 1980s, fell into eclipse again
in the first decade of the new century, and has returned like gangbusters in
the second, fueled largely by the increased processing power of graphics
chips.
“There’s this idea that ideas in science are a bit like epidemics of viruses,”
says Tomaso Poggio, the Eugene McDermott Professor of Brain and Cognitive
Sciences at MIT, an investigator at MIT’s McGovern Institute for Brain
Research, and director of MIT’s Center for Brains, Minds, and Machines .
“There are apparently five or six basic strains of flu viruses, and apparently
each one comes back with a period of around 25 years. People get infected, and
they develop an immune response, and so they don’t get infected for the next
25 years. And then there is a new generation that is ready to be infected by
the same strain of virus. In science, people fall in love with an idea, get
excited about it, hammer it to death, and then get immunized — they get tired
of it. So ideas should have the same kind of periodicity!”
Weighty matters
Neural nets are a means of doing machine learning, in which a computer learns
to perform some task by analyzing training examples. Usually, the examples
have been hand-labeled in advance. An object recognition system, for instance,
might be fed thousands of labeled images of cars, houses, coffee cups, and so
on, and it would find visual patterns in the images that consistently
correlate with particular labels.
Modeled loosely on the human brain, a neural net consists of thousands or even
millions of simple processing nodes that are densely interconnected. Most of
today’s neural nets are organized into layers of nodes, and they’re “feed-
forward,” meaning that data moves through them in only one direction. An
individual node might be connected to several nodes in the layer beneath it,
from which it receives data, and several nodes in the layer above it, to which
it sends data.
To each of its incoming connections, a node will assign a number known as a
“weight.” When the network is active, the node receives a different data item
— a different number — over each of its connections and multiplies it by the
associated weight. It then adds the resulting products together, yielding a
single number. If that number is below a threshold value, the node passes no
data to the next layer. If the number exceeds the threshold value, the node
“fires,” which in today’s neural nets generally means sending the number — the
sum of the weighted inputs — along all its outgoing connections.
When a neural net is being trained, all of its weights and thresholds are
initially set to random values. Training data is fed to the bottom layer — the
input layer — and it passes through the succeeding layers, getting multiplied
and added together in complex ways, until it finally arrives, radically
transformed, at the output layer. During training, the weights and thresholds
are continually adjusted until training data with the same labels consistently
yield similar outputs.
Minds and machines
The neural nets described by McCullough and Pitts in 1944 had thresholds and
weights, but they weren’t arranged into layers, and the researchers didn’t
specify any training mechanism. What McCullough and Pitts showed was that a
neural net could, in principle, compute any function that a digital computer
could. The result was more neuroscience than computer science: The point was
to suggest that the human brain could be thought of as a computing device.
Neural nets continue to be a valuable tool for neuroscientific research. For
instance, particular network layouts or rules for adjusting weights and
thresholds have reproduced observed features of human neuroanatomy and
cognition, an indication that they capture something about how the brain
processes information.
The first trainable neural network, the Perceptron, was demonstrated by the
Cornell University psychologist Frank Rosenblatt in 1957. The Perceptron’s
design was much like that of the modern neural net, except that it had only
one layer with adjustable weights and thresholds, sandwiched between input and
output layers.
Perceptrons were an active area of research in both psychology and the
fledgling discipline of computer science until 1959, when Minsky and Papert
published a book titled “Perceptrons,” which demonstrated that executing
certain fairly common computations on Perceptrons would be impractically time
consuming.
“Of course, all of these limitations kind of disappear if you take machinery
that is a little more complicated — like, two layers,” Poggio says. But at the
time, the book had a chilling effect on neural-net research.
“You have to put these things in historical context,” Poggio says. “They were
arguing for programming — for languages like Lisp. Not many years before,
people were still using analog computers. It was not clear at all at the time
that programming was the way to go. I think they went a little bit overboard,
but as usual, it’s not black and white. If you think of this as this
competition between analog computing and digital computing, they fought for
what at the time was the right thing.”
Periodicity
By the 1980s, however, researchers had developed algorithms for modifying
neural nets’ weights and thresholds that were efficient enough for networks
with more than one layer, removing many of the limitations identified by
Minsky and Papert. The field enjoyed a renaissance.
But intellectually, there’s something unsatisfying about neural nets. Enough
training may revise a network’s settings to the point that it can usefully
classify data, but what do those settings mean? What image features is an
object recognizer looking at, and how does it piece them together into the
distinctive visual signatures of cars, houses, and coffee cups? Looking at the
weights of individual connections won’t answer that question.
In recent years, computer scientists have begun to come up with ingenious
methods for deducing the analytic strategies adopted by neural nets. But in
the 1980s, the networks’ strategies were indecipherable. So around the turn of
the century, neural networks were supplanted by support vector machines, an
alternative approach to machine learning that’s based on some very clean and
elegant mathematics.
The recent resurgence in neural networks — the deep-learning revolution —
comes courtesy of the computer-game industry. The complex imagery and rapid
pace of today’s video games require hardware that can keep up, and the result
has been the graphics processing unit (GPU), which packs thousands of
relatively simple processing cores on a single chip. It didn’t take long for
researchers to realize that the architecture of a GPU is remarkably like that
of a neural net.
Modern GPUs enabled the one-layer networks of the 1960s and the two- to three-
layer networks of the 1980s to blossom into the 10-, 15-, even 50-layer
networks of today. That’s what the “deep” in “deep learning” refers to — the
depth of the network’s layers. And currently, deep learning is responsible for
the best-performing systems in almost every area of artificial-intelligence
research.
Under the hood
The networks’ opacity is still unsettling to theorists, but there’s headway on
that front, too. In addition to directing the Center for Brains, Minds, and
Machines (CBMM), Poggio leads the center’s research program in Theoretical
Frameworks for Intelligence . Recently, Poggio and his CBMM colleagues have
released a three-part theoretical study of neural networks.
The first part , which was published last month in the International
Journal of Automation and Computing , addresses the range of computations
that deep-learning networks can execute and when deep networks offer
advantages over shallower ones. Parts two and three , which have been
released as CBMM technical reports, address the problems of global
optimization, or guaranteeing that a network has found the settings that best
accord with its training data, and overfitting, or cases in which the network
becomes so attuned to the specifics of its training data that it fails to
generalize to other instances of the same categories.
There are still plenty of theoretical questions to be answered, but CBMM
researchers’ work could help ensure that neural networks finally break the
generational cycle that has brought them in and out of favor for seven
decades.
### Share this news article on:
* X
* Facebook
* LinkedIn
* Reddit
* Print
## Related Links
* Tomaso Poggio
* Center for Brains, Minds, and Machines
* McGovern Institute
* Department of Brain and Cognitive Sciences
* School of Science
## Related Topics
* Explained
* Artificial intelligence
* Brain and cognitive sciences
* Computer modeling
* Computer science and technology
* Machine learning
* Neuroscience
* History of science
* History of MIT
* Center for Brains Minds and Machines
## Related Articles
### Voice control everywhere
### Model sheds light on purpose of inhibitory neurons
### Learning words from pictures
### Computer learns to recognize sounds by watching video
Previous item Next item
## More MIT News
### Offering clean energy around the clock
MIT spinout 247Solar is building high-temperature concentrated solar power
systems that use overnight thermal energy storage to provide power and heat.
Read full story →
### Now corporate boards have responsibility for cybersecurity, too
Boards of directors are on the hook for management, governance, and disclosure
reporting.
Read full story →
### An AI dataset carves new paths to tornado detection
TorNet, a public artificial intelligence dataset, could help models reveal
when and why tornadoes form, improving forecasters' ability to issue warnings.
Read full story →
### MIT faculty, instructors, students experiment with generative AI in
teaching and learning
At MIT’s Festival of Learning 2024, panelists stressed the importance of
developing critical thinking skills while leveraging technologies like
generative AI.
Read full story →
### Julie Shah named head of the Department of Aeronautics and Astronautics
An expert in robotics and AI, Shah succeeds Steven Barrett at AeroAstro.
Read full story →
### Remembering Chasity Nunez, a shining star at MIT Health
A “perpetual learner,” Nunez was beloved at MIT and in her community.
Read full story →
* More news on MIT News homepage →
## More about MIT News at Massachusetts Institute of Technology
This website is managed by the MIT News Office, part of the Institute Office
of Communications .
### News by Schools/College:
* School of Architecture and Planning
* School of Engineering
* School of Humanities, Arts, and Social Sciences
* MIT Sloan School of Management
* School of Science
* MIT Schwarzman College of Computing
### Resources:
* About the MIT News Office
* MIT News Press Center
* Terms of Use
* Press Inquiries
* Filming Guidelines
* RSS Feeds
### Tools:
* Subscribe to MIT Daily/Weekly
* Subscribe to press releases
* Submit campus news
* Guidelines for campus news contributors
* Guidelines on generative AI
Massachusetts Institute of Technology
MIT Top Level Links:
* Education
* Research
* Innovation
* Admissions + Aid
* Campus Life
* News
* Alumni
* About MIT
* Join us in building a better world.
Massachusetts Institute of Technology
77 Massachusetts Avenue, Cambridge, MA, USA
Recommended Links:
* Visit
* Map (opens in new window)
* Events (opens in new window)
* People (opens in new window)
* Careers (opens in new window)
* Contact
* Privacy
* Accessibility
* * Social Media Hub
* MIT on X
* MIT on Facebook
* MIT on YouTube
* MIT on Instagram
| biology | 1026307 | https://da.wikipedia.org/wiki/Deep%20learning | Deep learning | Deep learning (også: deep structured learning eller hierarchical learning) er en del af området maskinlæring via kunstige neurale netværk. Deep learning er baseret på en konfiguration af algoritmer, som forsøger at modellere abstraktioner i data på højt niveau ved at anvende mange proceslag med komplekse strukturer, bestående af mange lineare og ikke-linear afbildninger.
Deep learning kan være overvåget, halv-overvåget eller uovervåget og har fået stor gennemslagskraft indenfor blandt andet billedklassificering, computervision, sprogbehandling, biostatistik og lydgenkendelse.
Geoffrey Hinton, Yann LeCun och Yoshua Bengio er pionerer indenfor deep learning.
Se også
Kunstig intelligens
Genetisk programmering
Referencer
Kunstig intelligens
Matematisk optimering
Maskinlæring | danish | 0.665675 |
neurons_learn/Hebbian_theory.txt | Hebbian theory is a neuropsychological theory claiming that an increase in synaptic efficacy arises from a presynaptic cell's repeated and persistent stimulation of a postsynaptic cell. It is an attempt to explain synaptic plasticity, the adaptation of brain neurons during the learning process. It was introduced by Donald Hebb in his 1949 book The Organization of Behavior. The theory is also called Hebb's rule, Hebb's postulate, and cell assembly theory. Hebb states it as follows:
The theory is often summarized as "Cells that fire together wire together." However, Hebb emphasized that cell A needs to "take part in firing" cell B, and such causality can occur only if cell A fires just before, not at the same time as, cell B. This aspect of causation in Hebb's work foreshadowed what is now known about spike-timing-dependent plasticity, which requires temporal precedence.
The theory attempts to explain associative or Hebbian learning, in which simultaneous activation of cells leads to pronounced increases in synaptic strength between those cells. It also provides a biological basis for errorless learning methods for education and memory rehabilitation. In the study of neural networks in cognitive function, it is often regarded as the neuronal basis of unsupervised learning.
Hebbian engrams and cell assembly theory[edit]
Hebbian theory concerns how neurons might connect themselves to become engrams. Hebb's theories on the form and function of cell assemblies can be understood from the following:
The general idea is an old one, that any two cells or systems of cells that are repeatedly active at the same time will tend to become 'associated' so that activity in one facilitates activity in the other.
Hebb also wrote:
When one cell repeatedly assists in firing another, the axon of the first cell develops synaptic knobs (or enlarges them if they already exist) in contact with the soma of the second cell.
[D. Alan Allport] posits additional ideas regarding cell assembly theory and its role in forming engrams, along the lines of the concept of auto-association, described as follows:
If the inputs to a system cause the same pattern of activity to occur repeatedly, the set of active elements constituting that pattern will become increasingly strongly inter-associated. That is, each element will tend to turn on every other element and (with negative weights) to turn off the elements that do not form part of the pattern. To put it another way, the pattern as a whole will become 'auto-associated'. We may call a learned (auto-associated) pattern an engram.
Work in the laboratory of Eric Kandel has provided evidence for the involvement of Hebbian learning mechanisms at synapses in the marine gastropod Aplysia californica. Experiments on Hebbian synapse modification mechanisms at the central nervous system synapses of vertebrates are much more difficult to control than are experiments with the relatively simple peripheral nervous system synapses studied in marine invertebrates. Much of the work on long-lasting synaptic changes between vertebrate neurons (such as long-term potentiation) involves the use of non-physiological experimental stimulation of brain cells. However, some of the physiologically relevant synapse modification mechanisms that have been studied in vertebrate brains do seem to be examples of Hebbian processes. One such study reviews results from experiments that indicate that long-lasting changes in synaptic strengths can be induced by physiologically relevant synaptic activity working through both Hebbian and non-Hebbian mechanisms.
Principles[edit]
From the point of view of artificial neurons and artificial neural networks, Hebb's principle can be described as a method of determining how to alter the weights between model neurons. The weight between two neurons increases if the two neurons activate simultaneously, and reduces if they activate separately. Nodes that tend to be either both positive or both negative at the same time have strong positive weights, while those that tend to be opposite have strong negative weights.
The following is a formulaic description of Hebbian learning: (many other descriptions are possible)
w
i
j
=
x
i
x
j
{\displaystyle \,w_{ij}=x_{i}x_{j}}
where
w
i
j
{\displaystyle w_{ij}}
is the weight of the connection from neuron
j
{\displaystyle j}
to neuron
i
{\displaystyle i}
and
x
i
{\displaystyle x_{i}}
the input for neuron
i
{\displaystyle i}
. Note that this is pattern learning (weights updated after every training example). In a Hopfield network, connections
w
i
j
{\displaystyle w_{ij}}
are set to zero if
i
=
j
{\displaystyle i=j}
(no reflexive connections allowed). With binary neurons (activations either 0 or 1), connections would be set to 1 if the connected neurons have the same activation for a pattern.
When several training patterns are used the expression becomes an average of individual ones:
w
i
j
=
1
p
∑
k
=
1
p
x
i
k
x
j
k
{\displaystyle w_{ij}={\frac {1}{p}}\sum _{k=1}^{p}x_{i}^{k}x_{j}^{k}}
where
w
i
j
{\displaystyle w_{ij}}
is the weight of the connection from neuron
j
{\displaystyle j}
to neuron
i
{\displaystyle i}
,
p
{\displaystyle p}
is the number of training patterns and
x
i
k
{\displaystyle x_{i}^{k}}
the
k
{\displaystyle k}
-th input for neuron
i
{\displaystyle i}
. This is learning by epoch (weights updated after all the training examples are presented), being last term applicable to both discrete and continuous training sets. Again, in a Hopfield network, connections
w
i
j
{\displaystyle w_{ij}}
are set to zero if
i
=
j
{\displaystyle i=j}
(no reflexive connections).
A variation of Hebbian learning that takes into account phenomena such as blocking and many other neural learning phenomena is the mathematical model of Harry Klopf. Klopf's model reproduces a great many biological phenomena, and is also simple to implement.
Relationship to unsupervised learning, stability, and generalization[edit]
Because of the simple nature of Hebbian learning, based only on the coincidence of pre- and post-synaptic activity, it may not be intuitively clear why this form of plasticity leads to meaningful learning. However, it can be shown that Hebbian plasticity does pick up the statistical properties of the input in a way that can be categorized as unsupervised learning.
This can be mathematically shown in a simplified example. Let us work under the simplifying assumption of a single rate-based neuron of rate
y
(
t
)
{\displaystyle y(t)}
, whose inputs have rates
x
1
(
t
)
.
.
.
x
N
(
t
)
{\displaystyle x_{1}(t)...x_{N}(t)}
. The response of the neuron
y
(
t
)
{\displaystyle y(t)}
is usually described as a linear combination of its input,
∑
i
w
i
x
i
{\displaystyle \sum _{i}w_{i}x_{i}}
, followed by a response function
f
{\displaystyle f}
:
y
=
f
(
∑
i
=
1
N
w
i
x
i
)
.
{\displaystyle y=f\left(\sum _{i=1}^{N}w_{i}x_{i}\right).}
As defined in the previous sections, Hebbian plasticity describes the evolution in time of the synaptic weight
w
{\displaystyle w}
:
d
w
i
d
t
=
η
x
i
y
.
{\displaystyle {\frac {dw_{i}}{dt}}=\eta x_{i}y.}
Assuming, for simplicity, an identity response function
f
(
a
)
=
a
{\displaystyle f(a)=a}
, we can write
d
w
i
d
t
=
η
x
i
∑
j
=
1
N
w
j
x
j
{\displaystyle {\frac {dw_{i}}{dt}}=\eta x_{i}\sum _{j=1}^{N}w_{j}x_{j}}
or in matrix form:
d
w
d
t
=
η
x
x
T
w
.
{\displaystyle {\frac {d\mathbf {w} }{dt}}=\eta \mathbf {x} \mathbf {x} ^{T}\mathbf {w} .}
As in the previous chapter, if training by epoch is done an average
⟨
…
⟩
{\displaystyle \langle \dots \rangle }
over discrete or continuous (time) training set of
x
{\displaystyle \mathbf {x} }
can be done:
d
w
d
t
=
⟨
η
x
x
T
w
⟩
=
η
⟨
x
x
T
⟩
w
=
η
C
w
.
{\displaystyle {\frac {d\mathbf {w} }{dt}}=\langle \eta \mathbf {x} \mathbf {x} ^{T}\mathbf {w} \rangle =\eta \langle \mathbf {x} \mathbf {x} ^{T}\rangle \mathbf {w} =\eta C\mathbf {w} .}
where
C
=
⟨
x
x
T
⟩
{\displaystyle C=\langle \,\mathbf {x} \mathbf {x} ^{T}\rangle }
is the correlation matrix of the input under the additional assumption that
⟨
x
⟩
=
0
{\displaystyle \langle \mathbf {x} \rangle =0}
(i.e. the average of the inputs is zero). This is a system of
N
{\displaystyle N}
coupled linear differential equations. Since
C
{\displaystyle C}
is symmetric, it is also diagonalizable, and the solution can be found, by working in its eigenvectors basis, to be of the form
w
(
t
)
=
k
1
e
η
α
1
t
c
1
+
k
2
e
η
α
2
t
c
2
+
.
.
.
+
k
N
e
η
α
N
t
c
N
{\displaystyle \mathbf {w} (t)=k_{1}e^{\eta \alpha _{1}t}\mathbf {c} _{1}+k_{2}e^{\eta \alpha _{2}t}\mathbf {c} _{2}+...+k_{N}e^{\eta \alpha _{N}t}\mathbf {c} _{N}}
where
k
i
{\displaystyle k_{i}}
are arbitrary constants,
c
i
{\displaystyle \mathbf {c} _{i}}
are the eigenvectors of
C
{\displaystyle C}
and
α
i
{\displaystyle \alpha _{i}}
their corresponding eigen values.
Since a correlation matrix is always a positive-definite matrix, the eigenvalues are all positive, and one can easily see how the above solution is always exponentially divergent in time.
This is an intrinsic problem due to this version of Hebb's rule being unstable, as in any network with a dominant signal the synaptic weights will increase or decrease exponentially. Intuitively, this is because whenever the presynaptic neuron excites the postsynaptic neuron, the weight between them is reinforced, causing an even stronger excitation in the future, and so forth, in a self-reinforcing way. One may think a solution is to limit the firing rate of the postsynaptic neuron by adding a non-linear, saturating response function
f
{\displaystyle f}
, but in fact, it can be shown that for any neuron model, Hebb's rule is unstable. Therefore, network models of neurons usually employ other learning theories such as BCM theory, Oja's rule, or the generalized Hebbian algorithm.
Regardless, even for the unstable solution above, one can see that, when sufficient time has passed, one of the terms dominates over the others, and
w
(
t
)
≈
e
η
α
∗
t
c
∗
{\displaystyle \mathbf {w} (t)\approx e^{\eta \alpha ^{*}t}\mathbf {c} ^{*}}
where
α
∗
{\displaystyle \alpha ^{*}}
is the largest eigenvalue of
C
{\displaystyle C}
. At this time, the postsynaptic neuron performs the following operation:
y
≈
e
η
α
∗
t
c
∗
x
{\displaystyle y\approx e^{\eta \alpha ^{*}t}\mathbf {c} ^{*}\mathbf {x} }
Because, again,
c
∗
{\displaystyle \mathbf {c} ^{*}}
is the eigenvector corresponding to the largest eigenvalue of the correlation matrix between the
x
i
{\displaystyle x_{i}}
s, this corresponds exactly to computing the first principal component of the input.
This mechanism can be extended to performing a full PCA (principal component analysis) of the input by adding further postsynaptic neurons, provided the postsynaptic neurons are prevented from all picking up the same principal component, for example by adding lateral inhibition in the postsynaptic layer. We have thus connected Hebbian learning to PCA, which is an elementary form of unsupervised learning, in the sense that the network can pick up useful statistical aspects of the input, and "describe" them in a distilled way in its output.
Limitations[edit]
Despite the common use of Hebbian models for long-term potentiation, Hebb's principle does not cover all forms of synaptic long-term plasticity. Hebb did not postulate any rules for inhibitory synapses, nor did he make predictions for anti-causal spike sequences (presynaptic neuron fires after the postsynaptic neuron). Synaptic modification may not simply occur only between activated neurons A and B, but at neighboring synapses as well. All forms of hetero synaptic and homeostatic plasticity are therefore considered non-Hebbian. An example is retrograde signaling to presynaptic terminals. The compound most commonly identified as fulfilling this retrograde transmitter role is nitric oxide, which, due to its high solubility and diffusivity, often exerts effects on nearby neurons. This type of diffuse synaptic modification, known as volume learning, is not included in the traditional Hebbian model.
Hebbian learning account of mirror neurons[edit]
Hebbian learning and spike-timing-dependent plasticity have been used in an influential theory of how mirror neurons emerge. Mirror neurons are neurons that fire both when an individual performs an action and when the individual sees or hears another perform a similar action. The discovery of these neurons has been very influential in explaining how individuals make sense of the actions of others, by showing that, when a person perceives the actions of others, the person activates the motor programs which they would use to perform similar actions. The activation of these motor programs then adds information to the perception and helps predict what the person will do next based on the perceiver's own motor program. A challenge has been to explain how individuals come to have neurons that respond both while performing an action and while hearing or seeing another perform similar actions.
Christian Keysers and David Perrett suggested that as an individual performs a particular action, the individual will see, hear, and feel the performing of the action. These re-afferent sensory signals will trigger activity in neurons responding to the sight, sound, and feel of the action. Because the activity of these sensory neurons will consistently overlap in time with those of the motor neurons that caused the action, Hebbian learning predicts that the synapses connecting neurons responding to the sight, sound, and feel of an action and those of the neurons triggering the action should be potentiated. The same is true while people look at themselves in the mirror, hear themselves babble, or are imitated by others. After repeated experience of this re-afference, the synapses connecting the sensory and motor representations of an action are so strong that the motor neurons start firing to the sound or the vision of the action, and a mirror neuron is created.
Evidence for that perspective comes from many experiments that show that motor programs can be triggered by novel auditory or visual stimuli after repeated pairing of the stimulus with the execution of the motor program (for a review of the evidence, see Giudice et al., 2009). For instance, people who have never played the piano do not activate brain regions involved in playing the piano when listening to piano music. Five hours of piano lessons, in which the participant is exposed to the sound of the piano each time they press a key is proven sufficient to trigger activity in motor regions of the brain upon listening to piano music when heard at a later time. Consistent with the fact that spike-timing-dependent plasticity occurs only if the presynaptic neuron's firing predicts the post-synaptic neuron's firing, the link between sensory stimuli and motor programs also only seem to be potentiated if the stimulus is contingent on the motor program.
See also[edit]
Dale's principle
Coincidence detection in neurobiology
Leabra
Metaplasticity
Tetanic stimulation
Synaptotropic hypothesis
Neuroplasticity
Behaviorism | biology | 1177729 | https://sv.wikipedia.org/wiki/Hebbs%20teori | Hebbs teori | Hebbs teori (även kallad Hebbs postulat eller Hebbs regel) är en teori inom neurovetenskapen som föreslår en mekanism för vad som händer med nervcellerna i hjärnan när inlärning sker, och hur dessa nervceller anpassar sig. Teorin lades fram av Donald Olding Hebb 1949. Teorin beskriver en mekanism för hur synapserna blir mer effektiva.
Teorin säger att en upprepande eller kvarvarande stimulering kommer att leda till en tillväxtprocess eller metabolisk förändring i den ena eller båda cellerna som leder till en ökad effektivitet i synapsen.
Teorin sammanfattas vanligtvis med "celler som avfyras tillsammans, sammankopplas" (eng. "cells that fire together, wire together"). Även om detta är en överförenkling som inte ska tas bokstavligen har teorin använts för att förklara vissa typer av associationsinlärning. Vid denna typ av inlärning kommer simultan aktivering av celler leda till en uttalad ökning i synaptisk styrka – denna inlärning är känd som hebbiansk inlärning.
Hebbs engram och cellsammanslutningsteori
Hebbs teori behandlar hur neuron skulle kunna sammankopplas för att bilda ett engram.
Gordon Allport placerar ytterligare idéer angående cellsammankopplingsteorin och dess roll i formering av engram, i linje med auto-association.
Hebbs teori har blivit den primära basen för den vanliga tanken att engram är neurala nät eller neurala nätverk, vid analyserande från ett holistiskt synsätt.
Eric R. Kandel har visat vissa bevis för denna teori genom att studera den vattenlevande snigeln Aplysia californica.
Experiment på mekanismer som modifierar Hebbs synaps i det centrala nervsystemets synapser hos ryggradsdjur är mycket svårare att kontrollera än hos de relativt enkla perifera nervsystem med sypapser som finns hos marina ryggradslösa djur. Mycket av arbetet hos långvariga synaptiska experiment mellan neuron (såsom long-term potentiation) involverar användandet av icke-fysiologisk experimentell stimulering av neuron.
Dock verkar några fysiologiskt relevanta synapsmodifieringar hos mekanismerna som studerats hos ryggradsdjur vara exempel på hebbianska processer. Sammanställningar av experiment pekar på att långvariga förändringar i synaptisk styrka kan induceras av fysiologiskt relevant synaptisk aktivitet genom både hebbianska och icke-hebbianska mekanismer.
Principer
Utifrån perspektivet av artificiella neuron och artificiella neurala nätverk, kan Hebbs teori användas för att beskriva hur man ska förändra viktningen mellan modell och neuron. Viktningen mellan två neuron ökar ifall bägge neuron aktiveras simultant och minskar ifall de aktiveras separat. Nod-par som tenderar ha en inbördes enhetlighet (antingen positiva eller negativa) vid samma tidpunkt, har stark positiv viktning och de som tenderar att ha motsatt förhållande har stark negativ viktning.
Denna ursprungliga princip är kanske den enklaste formen av viktningsurval. Den kan relativt enkelt omkodas till ett datorprogram och sedan användas för att vikta ett nätverk. Detta medför flera användningsområden för hebbiansk inlärning. Idag används termen hebbiansk inlärning som ett generellt samlingsnamn för olika former av matematiska abstraktioner av den ursprungliga principen som Hebb lade fram.
Se även
BCM teori
Long-term potentiation
Minne
Metaplasticitet
Neurala nätverk
Källor
Litteratur
Externa länkar
Översikt
Hebbian Learning tutorial (Part 1: Novelty Filtering, Part 2: PCA)
Neurofysiologi | swedish | 0.473422 |
smallest_genome/PMC4956268.txt | Skip to main content
U.S. flagAn official website of the United States government Here's how you know
NIH NLM LogoLog in
Access keysNCBI HomepageMyNCBI HomepageMain ContentMain Navigation
Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now.
Search PMC Full-Text Archive
Search PMC Full-Text Archive
Search in PMC
Advanced Search User Guide
Journal List PLoS Genet v.12(7); 2016 Jul PMC4956268
As a library, NLM provides access to scientific literature. Inclusion in an NLM database does not imply endorsement of, or agreement with, the contents by NLM or the National Institutes of Health.
Learn more: PMC Disclaimer | PMC Copyright Notice
Logo of plosgen
PLoS Genet. 2016 Jul; 12(7): e1006181.
Published online 2016 Jul 21. doi: 10.1371/journal.pgen.1006181
PMCID: PMC4956268
PMID: 27442251
What Is a Genome?
Aaron David Goldman1,* and Laura F. Landweber2,3,*
W. Ford Doolittle, Editor
Author information Copyright and License information PMC Disclaimer
See "How microbes “jeopardize” the modern synthesis" in volume 15, e1008166.
Go to:
Abstract
The genome is often described as the information repository of an organism. Whether millions or billions of letters of DNA, its transmission across generations confers the principal medium for inheritance of organismal traits. Several emerging areas of research demonstrate that this definition is an oversimplification. Here, we explore ways in which a deeper understanding of genomic diversity and cell physiology is challenging the concepts of physical permanence attached to the genome as well as its role as the sole information source for an organism.
Go to:
Introduction
The term genome was coined in 1920 to describe “the haploid chromosome set, which, together with the pertinent protoplasm, specifies the material foundations of the species” [1]. The term did not catch on immediately (Fig 1). Though Mendelian genetics was rediscovered in 1900, and chromosomes were identified as the carriers of genetic information in 1902 [2], it was not known in 1920 whether the genetic information was carried by the DNA or protein component of the chromosomes [3]. Furthermore, the mechanism by which the cell copies information into new cells [4] and converts that information into functions [5] was unknown for several decades after the term “genome” was coined.
An external file that holds a picture, illustration, etc.
Object name is pgen.1006181.g001.jpg
Fig 1
The change in usage of the term “genome” compared to related terms.
A Google ngram [6] analysis shows the case-insensitive occurrences of the terms “gene,” “genome,” and “chromosome” in the corpus of books in English from 1920 to 2008. The data are smoothed by a three-year moving average. The term “genome” was coined in 1920 [1], and many sources, including the Oxford English Dictionary, attribute the word to a portmanteau of the words “gene” and “chromosome,” although this etymology is disputed [1]. The term took decades to enter popular usage and only achieved its current level of usage by the turn of this century.
Today, however, we are awash in genomic data. A recent release of the GenBank database [7], version 210.0 (released on October 15, 2015), contains over 621 billion base pairs from 2,557 eukaryal genomes, 432 archaeal genomes, and 7,474 bacterial genomes, as well as tens of thousands of viral genomes, organellar genomes, and plasmid sequences (http://www.ncbi.nlm.nih.gov/genome/browse/, on December 13, 2015). We also now have much broader and more detailed understandings of how the genome is expressed and how different biological and environmental factors contribute to that process. Even so, almost a century after coining the term, the standard definition of the genome remains very similar to its 1920 predecessor. For example, on its Genetics Home Reference website, the National Institutes of Health (NIH) definition reads: “An organism’s complete set of DNA, including all of the genes, makes up the genome. Each genome contains all of the information needed to build and maintain that organism” (http://ghr.nlm.nih.gov/handbook/hgp/genome, on February 1, 2016).
With a greater understanding of genomic content, diversity, and expression, we can now reassess our basic understanding of the genome and its role in the cell. For example, closer scrutiny of the NIH definition reveals that its two halves are mutually exclusive; that is, the “complete set of DNA” cannot be “all of the information needed to build and maintain (an) organism.” Of course, this was probably meant to be a simplified definition for both scientists and nonscientists. While it is useful to continue thinking of the genome as a physical entity encoding the information required to maintain and replicate an organism, our present understanding shows that this definition is incomplete.
Go to:
Examples of Physical Transience in Genomes
Many diverse genetic systems challenge the material definition of the genome as “the complete set of chromosomes” [1] or “an organism’s complete set of DNA” (http://ghr.nlm.nih.gov/handbook/hgp/genome). Perhaps the most familiar and straightforward example of a genome’s physical impermanence occurs in the retroviral infection cycle. Upon infection, retroviruses convert their single-stranded RNA genomes into double-stranded DNA. These intermediate DNA copies of the genome are integrated into the host cell and, thus, no longer constitute a separate physical entity from the host’s genome. As an integrated DNA sequence, transcription into mRNA can both express retroviral genes and also reconstitute the original single-stranded (ss)RNA genome. Other types of viruses share similar features. Many temperate phages and viruses integrate into the host’s genome, removing themselves and lysing the host cell only after certain conditions are met. The hepadnaviruses, including Hepatitis B, infect the cell as double-stranded DNA, but are transcribed after infection into single-stranded RNA and subsequently follow a similar course as the retroviruses, wherein they are reverse transcribed back into DNA [8].
The chemical conversions of these genomes between different nucleic acids offer cogent examples that challenge our assumption of the physical permanence of genomes. It is tempting to explain this physical transience as another eccentric quirk of viruses. Many viruses, after all, do not have genomes composed of double-stranded DNA, a feature that already flouts the NIH definition given earlier. But an equally cogent example of the physical impermanence of a genome is found in the eukaryotic genus Oxytricha [9–11], a group of ciliates that are distantly related to Tetrahymena and Paramecium [12].
Like other ciliates, Oxytricha possesses two distinct versions of its genome, a germline version and a somatic version. Oxytricha’s germline genome is an archive of approximately 1 Gb of DNA sequence containing approximately one-quarter million embedded gene segments. These DNA pieces assemble following sexual recombination to form the somatic, expressed chromosomes (Fig 2). Thousands of these gene segments are present within the germline chromosomes in a scrambled order or reverse orientation, such that their reassembly requires translocation and/or inversion with respect to one another [13]. The resulting somatic genome, containing protein-coding sequences in the correct order, contains just 5%–10% the original sequence of the germline genome. This somatic genome resides on over 16,000 unique “nanochromosomes” that typically bear single genes and have an average size of just 3.2 kb [14]. These nanochromosomes also exist in high copy number, averaging approximately 2,000 copies per unique chromosome [14,15].
An external file that holds a picture, illustration, etc.
Object name is pgen.1006181.g002.jpg
Fig 2
The transfer of genomic information from DNA to RNA in Oxytricha trifallax.
The physical transition of genomic information from DNA to RNA and back to DNA occurs after mating in the ciliate, Oxytricha trifallax. RNA templates (wavy green line) and piRNAs (green dashes) derive from RNA transcripts of the previous generation’s somatic DNA nanochromosomes before the old somatic nucleus degrades. A mitotic copy of the new, zygotic germline genome provides precursor DNA segments (numbers 1–4) that are retained in the developing somatic nucleus through piRNA associations and rearranged according to the inherited RNA templates. This step sometimes reorders or inverts precursor segments to build the mature DNA molecule. The number of copies of each new nanochromosome is also influenced by the concentration of RNA templates supplied by the previous somatic genome during development. Red rectangles represent telomeres added to the ends of somatic chromosomes. Only one representative nanochromosome (of over 16,000 in Oxytricha) is shown for simplicity, and it derives from a representative locus containing 4 scrambled precursor segments in the germline genome.
Much of the information required to reproduce the somatic genome derives from RNA rather than DNA. Long, RNA-cached copies of somatic chromosomes from the previous generation provide templates to guide chromosome rearrangement [16]. Germline transposases participate in the whole process, probably by facilitating DNA cleavage events [17,18] that allow genomic regions to rearrange in the order according to the RNA templates [16]. Experimental introduction of long artificial RNAs can reprogram a developing Oxytricha cell to follow the order of gene segments specified by the artificial RNA templates, rather than the wild-type chromosome.
RNA performs other essential roles in building Oxytricha’s somatic genome. Millions of small, 27-nt piRNAs, which also derive from the previous generation’s somatic genome, mark and protect the retained DNA regions in the new zygotic germline that assemble (according to the RNA template) to form the new somatic genome [19,20]. In addition, the relative abundance of the long template RNAs also establishes chromosome copy number in the daughter cells [17]. Because these RNA templates derive from the previous generation’s somatic genome, this means that both the genomic sequence and chromosome ploidy are inherited from the old somatic nucleus to the new somatic nucleus through information transfer from DNA to RNA and back again to DNA.
These examples of physical transience in genomes show that a genome’s chemical composition and stability are not necessarily fixed requirements at all times in every organism. Synthetic biologists have further demonstrated this point through the chemical synthesis of viral [21,22] and bacterial [23] genomes. Prior to the chemical synthesis of these DNA chromosomes, the genomes existed in a purely informational state as nucleotide sequences in a computer file. In these cases, the genome of the virus or cell is not transferred from one type of nucleic acid to another, but from a physical DNA molecule to a non-physical nucleotide sequence and back again to a physical DNA molecule. Though this example is not a naturally occurring phenomenon, it provides a straightforward demonstration that the information content of the genome is more important than its physical permanence. Therefore, the concept of informational supremacy that is used to define genomes, e.g., “all of the information needed to build and maintain that organism,” also deserves further scrutiny.
Go to:
Extra-Genomic Information
Information is both an essential concept that underpins our understanding of a genome’s function and a notoriously difficult concept to define. The genome contains information, but so do other constituents of the cell. A typical and uncontroversial view is that the genome carries information but requires the presence of proteins, ribosomal RNAs, and transfer RNAs in the cell for the meaningful conversion of genomic information to molecular function. Indeed, the construction of synthetic genomes mentioned earlier required transplantation of the chemically synthesized genome into a pre-existing cell [23]. Evidence for heritable information beyond the genome has also been known since the 1960s [24]. A greater understanding of molecular biology has revealed that extra-genomic sources of information are not only required to read the genome but can influence the information encoded within the genome [25].
Epigenetic control of gene regulation provides a subtler—but in many ways more cogent—example of extra-genomic information. DNA methylation [26,27], histone modification encoding chromatin [28,29], and certain proteins (e.g., [30,31]) and noncoding RNAs [32,33], including Oxytricha’s noncoding RNAs described in the previous section [17,18,20], all offer platforms that permit information transfer across generations, while seeming to bypass the DNA genome. It has not yet been shown whether epigenetic information can persist over scales of evolutionary time, but it is clear that many if not most genomes have evolved a capacity for epigenetic control. This makes such genomes sensitive to external information that they do not encode, which, in turn, should influence their ability to adapt to changing environments while, in some cases, preserving the ability to revert to the former wild-type genome. This is epitomized by the genome duality in Oxytricha, in which millions of small and long noncoding RNAs sculpt and decrypt the information in its somatic epigenome, while the germline genome provides a more stable archive.
A second example of extra-genomic information has come by way of genome-wide association studies, which have identified correlations between many phenotypic traits and genetic variants [34]. In doing so, such studies have also revealed the so-called “missing heritability” problem, that genetic variation does not always account for 100% of the measured heritability, let alone the observed phenotypic variance, in many complex traits. In many cases, this missing heritability can be explained as a lack of statistical power due to low phenotypic impact of the genetic variation or low frequency in the population [35]. The missing heritability can also be explained, however, by a gene–environment interaction, such that the genes may only encode a trait that is expressed under certain environmental conditions [36,37]. In this example, genomes do not necessarily encode all of the information of the cell, but rather a set of potential states that may be realized through interaction with different environments.
As these examples demonstrate, the way in which the information content of the genome becomes realized as functions and phenotypes depends on other cellular constituents as well as the environment. The ability of genomes to be affected by this external information is, itself, encoded on the genome. In this way, genomes are not a sole source of cellular information, but rather a more expansive archive of possible states that can be generated through interactions with internal and external factors.
Go to:
Conclusion
Many biologists already know that the genome is not always best defined as “all of the information needed to build and maintain” a cell or an organism. While this definition is useful in the context of an online glossary for the public, it is, by necessity, an oversimplification. But if a genome is not a complete set of DNA containing all of the information needed to build and maintain the organism, then what is it?
We have demonstrated through examples from retroviruses, the microbial eukaryote Oxytricha, and synthetic biology that the genome can change its physical character while still maintaining the necessary information encoded within it. We also describe examples in which non-genomic factors can alter the way in which the information within the genome translates to molecular functions and phenotypes. These examples suggest a more expansive definition of the genome as an informational entity, often but not always manifest as DNA, encoding a broad set of functional possibilities that, together with other sources of information, produce and maintain the organism. Whether or not even this definition stands up to future discoveries remains to be seen.
Go to:
Acknowledgments
We thank Ford Doolittle and Susan Rosenberg for organizing this series of papers on “How Microbes ‘Jeopardize’ the Modern Synthesis.”
Go to:
Funding Statement
The authors received no specific funding for this work.
Go to:
References
1. Lederberg J, McCray AT. 'Ome Sweet 'Omics: A Genealogical Treasury of Words. The Scientist. 2001;15:8. [Google Scholar]
2. Sutton WS. On the morphology of the chromosome group in Brachystola magna. Biol. Bull. 1902;4:24–39 [Google Scholar]
3. Avery OT, MacLeod CM, McCarty M. Studies on the chemical nature of the substance inducing transformation of Pneumococcal types. J Exp Med, 1944;79:137–159. [PMC free article] [PubMed] [Google Scholar]
4. Watson JD, Crick FHC. Genetical Implications of the structure of Deoxyribonucleic Acid. Nature. 1953;171:964–967. [PubMed] [Google Scholar]
5. Crick FHC. On protein synthesis. Symp Soc Exp Biol. 1958;12:138–163. [PubMed] [Google Scholar]
6. Michel JB, Shen YK, Aiden AP, Veres A, Gray MK, et al. Quantitative analysis of culture using millions of digitized books. Science. 2011;331:176–182. 10.1126/science.1199644 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
7. Benson DA, Karsch-Mizrachi I, Lipman DJ, Ostell J, Wheeler DL. GenBank. Nucleic Acids Res. 2005;33:D34–D38. [PMC free article] [PubMed] [Google Scholar]
8. Nassal M, Schaller H. Hepatitis B virus replication. Trends Microbiol. 1993;1:221–228. [PubMed] [Google Scholar]
9. Nowacki M, Shetty K, Landweber LF. RNA-Mediated Epigenetic Programming of Genome Rearrangements. Annu Rev Genomics Hum Genet. 2011;12:367–389. 10.1146/annurev-genom-082410-101420 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
10. Goldman AD, Landweber LF. Oxytricha as a modern analog of ancient genome evolution. Trends Genet. 2012;28:382–388. 10.1016/j.tig.2012.03.010 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
11. Bracht JR, Fang W, Goldman AD, Dolzhenko E, Stein EM, Landweber LF. Genomes on the edge: programmed genome instability in ciliates. Cell. 2013;152:406–416. 10.1016/j.cell.2013.01.005 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
12. Zoller SD, Hammersmith RL, Swart EC, Higgins BP, Doak TG, et al. Characterization and taxonomic validity of the ciliate Oxytricha trifallax (Class Spirotrichea) based on multiple gene sequences: limitations in identifying genera solely by morphology. Protist. 2012;163:643–657 [PMC free article] [PubMed] [Google Scholar]
13. Chen X, Bracht JR, Goldman AD, Dolzhenko E, Clay DM, et al. The architecture of a scrambled genome reveals massive levels of genomic rearrangement during development. Cell. 2014;158:1187–98. 10.1016/j.cell.2014.07.034 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
14. Swart EC, Bracht JR, Magrini V, Minx P, Chen X, et al. The Oxytricha trifallax macronuclear genome: a complex eukaryotic genome with 16,000 tiny chromosomes. PLoS Biol. 2013;11:e1001473 10.1371/journal.pbio.1001473 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
15. Prescott DM. The DNA of ciliated protozoa. Microbiol Mol Biol Rev. 1994;58:233–267. [PMC free article] [PubMed] [Google Scholar]
16. Nowacki M, Vijayan V, Zhou Y, Schotanus K, Doak TG, Landweber LF. RNA-mediated epigenetic programming of a genome-rearrangement pathway. Nature. 2008;451:153–158. [PMC free article] [PubMed] [Google Scholar]
17. Nowacki M, Haye JE, Fang W, Vijayan V, Landweber LF. RNA-mediated epigenetic regulation of DNA copy number. Proc Natl Acad Sci U S A, 2010;107:22140–22144. 10.1073/pnas.1012236107 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
18. Vogt A, Goldman AD, Mochizuki K, Landweber LF. Transposon domestication versus mutualism in ciliate genome rearrangements. PLoS Genet. 2013;9:e1003659 10.1371/journal.pgen.1003659 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
19. Fang W, Wang X, Bracht JR, Nowacki M, Landweber LF. Piwi-interacting RNAs protect DNA against loss during Oxytricha genome rearrangement. Cell. 2012;151:1243–1255. 10.1016/j.cell.2012.10.045 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
20. Zahler AM, Neeb ZT, Lin A, Katzman S. Mating of the stichotrichous ciliate Oxytricha trifallax induces production of a class of 27 nt small RNAs derived from the parental macronucleus. PLoS ONE, 2012;7:e42371 10.1371/journal.pone.0042371 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
21. Cello J, Paul AV, Wimmer E. Chemical synthesis of poliovirus cDNA: generation of infectious virus in the absence of natural template. Science. 2002;297:1016–1018. [PubMed] [Google Scholar]
22. Smith HO, Hutchison CA 3rd, Pfannkoch C, Venter JC. Generating a synthetic genome by whole genome assembly: phiX174 bacteriophage from synthetic oligonucleotides. Proc Natl Acad Sci U S A. 2003;100:15440–5. [PMC free article] [PubMed] [Google Scholar]
23. Gibson DG, Glass JI, Lartigue C, Noskov VN, Chuang RY, et al. Creation of a bacterial cell controlled by a chemically synthesized genome. Science, 2010;329:52–56. 10.1126/science.1190719 [PubMed] [CrossRef] [Google Scholar]
24. Nanney DL. Corticotype transmission in Tetrahymena. Genetics. 1966;54:955–968. [PMC free article] [PubMed] [Google Scholar]
25. Walker SI. Top-down causation and the rise of information in the Emergence of Life. Information. 2014;5:424–439. [Google Scholar]
26. Riggs AD. X inactivation, differentiation, and DNA methylation. Cytogenet Cell Genet. 1975;14:9–25. [PubMed] [Google Scholar]
27. Jaenisch R, Bird A. Epigenetic regulation of gene expression: how the genome integrates intrinsic and environmental signals. Nat Genet. 2003;33:245–254. [PubMed] [Google Scholar]
28. D’Urso A, Brickner JH. Mechanisms of epigenetic memory. Trends Genet. 2014;30:230–236. 10.1016/j.tig.2014.04.004 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
29. Siklenka K, Erkek S, Godmann M, Lambrot R, McGraw S, et al. Disruption of histone methylation in developing sperm impairs offspring health transgenerationally. Science. 2015;350:aab2006 10.1126/science.aab2006 [PubMed] [CrossRef] [Google Scholar]
30. Zordan R, Miller M, Galgoczy D, Tuch B, Johnson A. Interlocking transcriptional feedback loops control white-opaque switching in Candida albicans. PLoS Biol. 2007;5:1–11. [PMC free article] [PubMed] [Google Scholar]
31. Zacharioudakis I, Gligoris T, Tzamarias D. A yeast catabolic enzyme controls transcriptional memory. Curr Biol. 2007;17:2041–2046. [PubMed] [Google Scholar]
32. Rassoulzadegan M, Grandjean V, Gounon P, Vincent S, Gillot I, Cuzin F. RNA-mediated non-Mendelian inheritance of an epigenetic change in the mouse. Nature. 2006;441:469–474. [PubMed] [Google Scholar]
33. Rodgers AB, Morgan CP, Leu NA, Bale TL. Transgenerational epigenetic programming via sperm microRNA recapitulates effects of paternal stress. Proc Natl Acad Sci U S A. 2015;112:13699–13704. 10.1073/pnas.1508347112 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
34. Bush WS, Moore JH. Chapter 11: Genome-Wide Association Studies. PLoS Comput Biol. 2012;8:e1002822 10.1371/journal.pcbi.1002822 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
35. Gibson G. Rare and common variants: twenty arguments. Nat Rev Genet. 2012;13:135–145. 10.1038/nrg3118 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
36. Smith EN, Kruglyak L. Gene-environment interaction in yeast gene expression. PLoS Biol. 2008;6:e83 10.1371/journal.pbio.0060083 [PMC free article] [PubMed] [CrossRef] [Google Scholar]
37. Manuck SB, McCaffery JM. Gene-environment interaction. Annu Rev Psychol. 2014;65:41–70. 10.1146/annurev-psych-010213-115100 [PubMed] [CrossRef] [Google Scholar]
Articles from PLOS Genetics are provided here courtesy of PLOS
OTHER FORMATS
PDF (939K)
ACTIONS
Cite
Collections
SHARE
RESOURCES
Similar articles
Cited by other articles
Links to NCBI Databases
FOLLOW NCBI
Connect with NLM
National Library of Medicine
8600 Rockville Pike
Bethesda, MD 20894
Web Policies
FOIA
HHS Vulnerability Disclosure
Help
Accessibility
Careers
NLM
NIH
HHS
USA.gov
Tell us what you think!Close
| biology | 4518 | https://da.wikipedia.org/wiki/DNA | DNA | Deoxyribonukleinsyre (DNA, fra det engelske ord Deoxyribonucleic acid) er et molekyle, som bærer på de fleste af de genetiske instruktioner, der bruges ved vækst, udvikling, funktion og reproduktion af alle kendte levende organismer og mange vira. DNA og RNA er nukleinsyrer, som sammen med proteiner, lipider og komplekse kulhydrater udgør de fire store typer makromolekyler, der er essentielle for alle kendte former for liv.
De fleste DNA-molekyler består af to biopolymer-strenge snoet omkring hinanden i en dobbelthelix. De to DNA-strenge er kendt som polynukleotider, siden de består af simplere enheder kaldet nukleotider. Hvert nukleotid består af en nitrogenholdig nukleobase — enten cytosin (C), guanin (G), adenin (A) eller thymin (T) — såvel som en sukker kaldet deoxyribose og en fosfatgruppe. Nukleotiderne forbindes med hinanden i en kæde af kovalente bindinger mellem sukker fra det ene nukleotid og fosfat fra det andet, hvilket resulterer i en alternerende sukker-fosfat-rygrad.
DNA kaldes organismens byggeplan fordi det opbevarer biologisk information.
DNA-rygraden er resistent over for spaltning, og begge strenge af den dobbelt-strengede struktur opbevarer den samme biologiske information. Biologisk information replikeres, idet de to strenge separeres. En betragtelig del af DNA (mere end 98 % for mennesker) er ikke-kodende, hvilket betyder, at disse sektioner ikke fungerer som koder for proteinsekvenser.
Inde i celler organiseres DNA i lange strukturer kaldet kromosomer. Under celledeling duplikeres disse kromosomer ved en proces kaldet DNA-replikation, hvilket giver hver celle sit eget komplette sæt af kromosomer. Eukaryote organismer (dyr, planter, svampe og protister) opbevarer det meste af deres DNA i cellekernen og noget af deres DNA i organeller, såsom mitokondrier eller grønkorn. I modsætning hertil opbevarer prokaryoter (bakterier og arkæer) kun deres DNA i cytoplasmaet. Inde i kromosomerne komprimeres og organiseres DNA'en af kromatinproteiner såsom histon. Disse kompakte strukturer guider interaktionerne mellem DNA og andre proteiner, og hjælper med at kontrollere, hvilke dele af DNA'en der transskriberes.
Egenskaber
DNA er en lang polymer lavet af gentagende enheder kaldet nukleotider. DNA's struktur er ikke-statisk, alle arter består af to heliske kæder, der hver snor sig om den samme akse, og hver med en bane på 34 ångström (3,4 nanometer) og en radius på 10 ångström (1,0 nanometer). Ifølge et andet studium kan DNA-kæden, i en bestemt opløsning, måles til at være 22 til 26 ångström bred (2,2 til 2,6 nanometer), og en nukleotidenhed blev målt til at være 3,3 Å (0,33 nm) lang. Selvom hver individuel gentagende enhed er meget lille, kan DNA-polymerer være meget store molekyler indeholdende millioner af nukleotider. For eksempel består DNA'en i det største menneskekromosom, kromosom nummer 1, af omkring 220 millioner basepar og ville være 85 mm langt, hvis det blev rettet ud.
I levende organismer eksisterer DNA normalt ikke som et enkelt molekyle, men derimod som et molekylepar, der holdes stramt sammen. Disse to lange strenge flettes omkring hinanden i form af en dobbelthelix. Hver nukleotidenhed indeholder både en del af molekylets rygradssegment, som holder kæden sammen, og en nukleobase, som interagerer med den anden DNA-streng i helixen. En nukleobase, der er forbundet med en sukker, kaldes et nukleosid, mens en base, der er forbundet med en sukker og en eller flere fosfatgrupper, kaldes et nukleotid. En polymer bestående af flere forbundne nukleotider (som i DNA) kaldes et polynukleotid.
DNA-strengens rygrad består af alternerende fosfat- og sukkergrupper. Sukkeret i DNA er 2-deoxyribose, som er en pentose (fem-carbon-sukker). Sukkeret bindes sammen af fosfatgrupper, som danner fosfodiesterbindinger mellem det tredje og femte carbonatom på nærliggende sukkerringe. Disse asymmetriske bindinger betyder, at en DNA-streng har en retning. I en dobbelthelix er retningen på nukleotiderne i en streng modsat af nukleotidernes retning i den anden streng: Strengene er antiparallelle. DNA-strengenes asymmetriske ender kaldes 5′-enden og 3′-enden, hvor 5′-enden har en terminal fosfatgruppe og 3′-enden har en terminal hydroxylgruppe. En stor forskel mellem DNA og RNA er sukkeret, der i DNA er 2-deoxyribose og i RNA den alternative pentosesukker ribose.
DNA-dobbelthelixen stabiliseres primært af to kræfter: hydrogenbindinger mellem nukleotider og basestablingsinteraktioner mellem aromatiske nukleobaser. I cellens vandige miljø tilpasser nukleobasernes konjugerede π-bindinger sig vinkelret på DNA-molekylets akse, hvilket minimerer deres interaktion med solvatiseringsskallen og derfor deres Gibbs fri energi. De fire baser i DNA er adenin (forkortet A), cytosin (C), guanin (G) og thymin (T). Disse fire baser forbindes til sukkeret/fosfatet for at danne det komplette nukleotid, som vist for adenosinmonofosfat. Adenin parres med thymin, mens guanin parres med cytosin. Det blev repræsenteret af A-T-basepar og G-C-basepar.
Nukleobaseklassifikation
Nukleobaserne klassificeres i to typer: purinerne, A og G, som er fusionerede fem- og seksdelte heterocykliske forbindelser, og pyrimidinerne, de seksleddede ringe C og T. En femte pyrimidinnukleobase, uracil (U), erstatter normalt thymin i RNA og adskiller sig fra thymin idet den mangler en methylgruppe på sin ring. Udover RNA og DNA er der også blevet skabt en lang række kunstige nukleinsyreanaloger til brug ved studier i nukleinsyrernes egenskaber, eller i bioteknologi.
Uracil findes normalt ikke i DNA og opstår kun som et nedbrydningsprodukt af cytosin. I en række bakteriofager – Bacillus subtilis-bakteriofagerne PBS1 og PBS2 og Yersinia-bakteriofagen piR1-37 – er thymin erstattet af uracil. En anden fag – stafylokokkerfag S6 – er blevet identificeret som et genom, hvor thymin er erstattet af uracil.
Base J (beta-d-glukopyranosyloxymethyluracil), en modificeret form af uracil, findes også i en række organismer: flagellaterne Diplonema og Euglena, og alle slægter af kinetoplastider. Biosyntese af J sker i to trin: i det første trin konverteres en specifik thymidin i DNA til hydroxymethyldeoxyuridin; i det andet glykosyleres HOMedU til at danne form J. Der er blevet fundet proteiner, der binder specifikt til denne base. Disse proteiner lader til at være en fjern slægtning til det Tet1-onkogen, der er involveret i patogenesen af akut myeloid leukæmi. J lader til at opføre sig som et terminationssignal for RNA polymerase II.
Riller
To heliske strenge udgør DNA'ens rygrad. En anden dobbelthelix kan findes ved at følge rummene, eller rillerne (på engelsk kaldet "grooves"), mellem strengene. Disse hulrum støder op til baseparrene og kan udgøre et bindingssted. Da strengene ikke ligger symmetrisk i forhold til hinanden, er rillerne af forskellig størrelse. En rille, den store rille, er 22 Å bred, mens den anden, den lille rille, er 12 Å bred. Bredden af den store rille medfører, at kanterne på baserne er mere tilgængelige i den store rille end i den lille. Som følge heraf får proteiner såsom transskriptionsfaktorer, der kan binde til specifikke sekvenser i dobbelt-strenget DNA, normalt kontakt med siderne af de baser, der er blotlagt i den store rille. Denne situation varierer i nogle usædvanlige DNA-konformere i cellen, men navnene "store" og "lille" rille er til for at reflektere de forskelle i størrelse, der ville ses, hvis DNA'en drejedes tilbage til almindelig B-form.
Baseparring
I en DNA-dobbelthelix binder hver type nukleobase på en streng kun til en bestemt type nukleobase på den anden streng. Dette kaldes komplementær baseparring. Her danner puriner hydrogenbindinger til pyrimidiner, idet adenin kun binder til thymin via to hydrogenbindinger, og cytosin kun binder til guanin via tre hydrogenbindinger. Dette arrangement af to nukleotider, der binder sig sammen på tværs af en dobbelthelix, kaldes et basepar. Da hydrogenbindinger ikke er kovalente, kan de brydes og genforenes relativt nemt. DNA's to strenge i en dobbelthelix kan derfor trækkes fra hinanden som en lynlås, enten ved mekanisk kraft eller høje temperaturer. Som følge af denne komplementaritet duplikeres al information i den dobbelt-strengede sekvens i en DNA-helix på hver streng, hvilket er livsvigtigt i DNA-replikation. Denne reversible og specifikke interaktion imellem komplementære basepar er kritisk for alle DNA's funktioner i levende organismer.
Øverst: et GC-basepar med tre hydrogenbindinger. Nederst: et AT-basepar med to hydrogenbindinger. Ikke-kovalente hydrogenbindinger mellem parrene vises som stiplede linjer.
De to typer basepar danner forskellige antal hydrogenbindinger, hvor AT danner to hydrogenbindinger og GC danner tre.
DNA med højt GC-indhold er mere stabilt end DNA med lavt GC-indhold.
Som bemærket ovenfor er de fleste DNA-molekyler i virkeligheden to polymerstrenge, bundet sammen i helisk form af ikke-kovalente bindinger; denne dobbeltstrengede struktur (dsDNA) vedligeholdes hovedsageligt af intrastrengs-basestablingsinteraktioner, som er stærkest for G,C-stakke. De to strenge kan adskilles fra hinanden – en proces kendt som smeltning – for at danne to enkelt-strengede DNA-molekyler (ssDNA, efter engelsk single-stringed DNA). Smeltning sker ved høje temperaturer, lav saltkoncentration og høj pH (lav pH smelter også DNA, men siden DNA er ustabilt pga. syreafpurinering bruges lav pH sjældent).
dsDNA-formens stabilitet afhænger ikke kun af GC-indholdet (% G,C-basepar), men også af sekvensen (siden stabling er sekvensspecifikt) og af længden (længere molekyler er mere stabile). Stabiliteten kan måles på forskellige måder; en udbredt måde er "smeltetemperaturen", hvilket er temperaturen hvor 50% af ds-molekylerne konverteres til ss-molekyler; smeltetemperaturer er afhængige af ionisk styrke og DNA'ens koncentration.
Som følge heraf er det både procentdelen af GC-basepar og den overordnede længde af DNA-dobbelthelixen, der afgør styrken af forbindelsen mellem de to DNA-strenge. Lange DNA-helixer med højt GC-indhold har stærkere-interagerende strenge, mens korte helixer med højt AT-indhold har svagere-interagerende strenge. Inden for biologien er der en tendens til, at dele af DNA-dobbelthelixen, som skal kunne separere nemt, såsom TATAAT Pribnow-boksen i nogle promotere, har højt AT-indhold, hvilket gør strengene lettere at trække fra hinanden.
I laboratoriet kan styrken af denne interaktion måles ved at finde den temperatur, der er nødvendig for at bryde hydrogenbindingerne, deres smeltetemperatur (også kaldet Tm-værdien). Når alle baseparrene i en DNA-dobbelthelix smelter, adskilles og eksisterer strengene i opløsning som to fuldstændigt uafhængige molekyler. Disse enkeltstrengede DNA-molekyler (ssDNA) har ingen almindelig form, men nogle konformere er mere stabile end andre.
Sense og antisense
En DNA-sekvens kaldes "sense" hvis dens sekvens er den samme som en messenger RNA-kopi, der translateres til protein. Sekvensen på den modsatte streng kaldes "antisense"-sekvensen. Både sense- og antisense-sekvenser kan eksistere på forskellige dele af den samme DNA-streng (dvs. begge strenge kan indeholde både sense- og antisensesekvenser). Antisense-RNA-sekvenser produceres i både prokaryoter og eukaryoter, men disse RNA'ers funktioner er ikke helt visse. En mulighed er, at antisense-RNA er involveret i reguleringen af genudtryk gennem RNA-RNA-baseparring.
Nogle få DNA-sekvenser i prokaryoter og eukaryoter, og flere i plasmider og vira, slører grænsen mellem sense- og antisense-strenge ved at have overlappende gener. I disse tilfælde fungerer nogle DNA-sekvenser dobbelt, og koder et protein når de læser langs en streng, og et andet protein når de læses i den modsatte retning langs den anden streng. I bakterier kan dette overlap være involveret i reguleringen af gentransskription, mens overlappende gener hos vira kan øge mængden af information, der kan indkodes i det lille virale genom.
Supercoiling
DNA kan snos som et reb ved en proces kaldet DNA supercoiling. I DNA'ens "afslappede" tilstand cirkler en streng normalt omkring dobbelthelixens akse en gang hvert 10,4 basepar, men hvis DNA'en snos, bliver strengene strammere eller løsere bundet. Hvis DNA'en snos i samme retning som helixen, kaldes dette positiv supercoiling, og baserne holdes strammere sammen. Hvis de snos i den modsatte retning, kaldes det negativ supercoiling, og baserne kan nemmere adskilles. I naturen har den meste DNA en let negativ supercoiling, der skyldes enzymerne topoisomerase. Disse enzymer behøves også for at aflaste de snoede spændinger, der introduceres i DNA-strenge under processer såsom transskription og DNA-replikation.
Alternative DNA-strukturer
DNA eksisterer i mange mulige konformere, der inkluderer A-DNA, B-DNA og Z-DNA, selvom kun B-DNA og Z-DNA er blevet direkte observeret i funktionelle organismer. Den konformer som DNA indtager afhænger af hydratiseringsniveauet, DNA-sekvensen, mængden og retningen af supercoiling, kemiske modifikationer af baserne, typen og koncentrationen af metalioner, såvel som tilstedeværelsen af polyaminer i opløsningen.
De første offentliggjorte rapporter om A-DNA-røntgendiffraktionsmønstre – såvel som B-DNA – brugte analyser baseret på Patterson-metoden, der kun gav begrænsede mængder strukturel information om orienterede DNA-fibre. En alternativ analyse blev efterfølgende foreslået af Wilkins et al., i 1953, for in vivo B-DNA røntgendiffraktionsmønstre af højt hydratiserede DNA-fibre i form af kvadrater af Besselfunktioner. I den samme journal præsenterede James Watson og Francis Crick deres molekylærmodelleringsanalyse af DNA-røntgendiffraktionsmønstrene for at sandsynliggøre at strukturen var en dobbelthelix.
Selvom "B-DNA-formen" er den mest almindelige under de forhold, der findes i celler, er den ikke en veldefineret konformer, men en familie af relaterede DNA-konformere, der finder sted på de høje hydratiseringsniveauer i levende celler. Deres tilsvarende røntgendiffraktions- og spredningsmønstre er karakteristiske for molekylære parakrystaller med en signifikant grad af uorden.
Sammenlignet med B-DNA er A-DNA-formen en bredere, højrehåndet spiral, med en overfladisk, bred lille rille og en smallere, dybere stor rille. A-formen fremkommer under ikke-fysiologiske forhold i delvist dehydrerede DNA-prøver, mens den i cellen kan produceres i hybridparringer af DNA- og RNA-strenge, såvel som i enzym-DNA-komplekser. Segmenter af DNA, hvor baserne er blevet kemisk modificeret ved methylering, kan undergå en større forandring i konformer og indtage Z-form. Her drejer strengene omkring den heliske akse i en venstrehåndet spiral, det modsatte af den mere almindelige B-form. Disse usædvanlige strukturer kan genkendes på specifikke Z-DNA-bindingsproteiner og kan være involveret i reguleringen af transskription.
Alternativ DNA-kemi
I en række år har exobiologer foreslået, at der findes en skyggebiosfære, en postuleret mikrobiel biosfære af Jorden som anvender radikalt anderledes biokemiske og molekylære processer end det liv der kendes i dag. Et af forslagene var eksistensen af livsformer, som bruger arsen i stedet for fosfor i DNA. En rapport om denne mulighed i bakterien GFAJ-1 blev bebudet i 2010, selvom forskningen var omstridt, og beviserne peger i retning af, at bakterien aktivt forhindrer inkorporeringen af arsen i DNA-rygraden og andre biomolekyler.
Quadruplexstrukturer
I enderne af de lineære kromosomer findes specialiserede DNA-regioner kaldet telomerer. Disse regioners centrale funktion er at tillade cellen at replikere kromosomender ved brug af enzymet telomerase, da enzymerne som normalt replikerer DNA ikke kan kopiere de yderste 3′-ender af kromosomer. Disse specialiserede 'kromosomdæksler' hjælper også med at beskytte DNA-enderne og stoppe DNA-reparationssystemerne i cellen fra at behandle dem som skade, der skal repareres. I menneskeceller har telomerer normalt en længde på enkelt-strenget DNA indeholdende flere tusinde gentagelser af en simpel TTAGGG-sekvens.
Disse guaninrige sekvenser kan stabilisere kromosomender ved at danne strukturer af stablede sæt af fire-baseenheder, snarere end de normale basepar i andre DNA-molekyler. Her danner fire guaninbaser en flad tallerken, og disse flade firebaseenheder stables derefter ovenpå hinanden for at danne en stabil G-quadruplexstruktur. Disse strukturer stabiliseres af hydrogenbindinger mellem basekanterne og chelat fra en metalion i midten af hver firebase-enhed. Der kan også dannes andre strukturer, hvor det centrale sæt af fire baser kommer fra enten en enkelt streng foldet omkring baserne, eller flere forskellige parallelle strenge, der hver bidrager med en base til den centrale struktur.
Udover disse stablede strukturer danner telomerer også store loopende strukturer kaldet telomerloops, eller T-loops. Her krøller den enkelt-strengede DNA sig sammen til en lang cirkel stabiliseret af telomerbindende proteiner. I den sidste ende af T-loopet holdes den enkelt-strengede telomer-DNA på en region af dobbelt-strenget DNA af den telomerstreng, der splitter den dobbeltheliske DNA og baseparring til en af de to strenge. Denne trippel-strengede struktur kaldes et D-loop.
Forgrenet DNA
Forgrenet DNA kan danne netværk indeholdende flere grene.
DNA "flosser", når ikke-komplementære regioner eksisterer i enden af en ellers komplementær dobbelt-strenget DNA. Forgrenet DNA kan dog opstå, hvis en tredje streng af DNA introduceres og indeholder tilstødende regioner i stand til at hybridisere med de flossede regioner i den allerede eksisterende dobbelt-streng. Selvom det mest simple eksempel på forgrenet DNA kun involverer tre DNA-strenge, er det også muligt at skabe komplekser med yderligere strenge og flere grene. Forgrenet DNA kan bruges i nanoteknologi til at konstruere geometriske former.
Kemiske modifikationer og ændret DNA-pakning
Basemodifikationer og DNA-pakning
Cytosins struktur med og uden 5-methyl-gruppen. Deaminering konverterer 5-methylcytosin til thymin.
Ekspressionen af gener påvirkes af, hvordan DNA'en pakkes i kromosomer, i en struktur kaldet kromatin. Basemodifikationer kan også være involverede i pakningen, hvor regioner med lav eller ingen genekspression normalt indeholder store mængder methylering af cytosinbaser. DNA-pakning og dens indflydelse på genekspression kan også ske ved kovalente modifikationer af histonproteinkernen, som DNA er pakket omkring i kromatinstrukturen, eller ved remodellering udført af kromatinremodelleringskomplekser. Herudover er der krydstale mellem DNA-methylering og histonmodifikation, så de kan koordinere deres påvirkning af kromatin og genekspression.
For at tage et eksempel, producerer cytosinmethylering 5-methylcytosin, som er vigtigt for X-kromosominaktivering. Det gennemsnitlige methyleringsniveau varierer mellem organismer – ormen Caenorhabditis elegans har ingen cytosinmethylering, mens hvirveldyr har højere niveauer, med 5-methylcytosin i op til 1% af deres DNA . På trods af 5-methylcytosins vigtighed har det den ulempe, at det kan deamineres til en thyminbase, hvilket gør methylerede cytosiner særligt sårbare over for mutationer. Blandt andre basemodifikationer er adeninmethylering i bakterier, tilstedeværelsen af 5-hydroxymethylcytosin i hjernen og glykosyleringen af uracil til "J-basen" i kinetoplastider.
Beskadigelse
DNA kan beskadiges af mange typer mutagener, som kan ændre DNA-sekvensen. Blandt disse mutagener er oxidations- og alkyleringsmidler, såvel som højenergi-elektromagnetisk stråling såsom ultraviolet lys og røntgenstråling. Typen af skade på DNA'en afhænger af typen af mutagen. For eksempel kan UV-lys beskadige DNA ved at producere thymindimerer, som er krydsbindinger mellem pyrimidinbaser. Omvendt forårsager oxidanter såsom frie radikale eller brintoverilte flere typer skade, heriblandt basemodifikationer, særligt af guanosin, og dobbelt-streng-brud. En typisk menneskecelle indeholder omkring 150.000 baser, som har lidt oxidativ skade. Af disse oxidative læsioner er de farligste dobbelt-strengede brud, da disse er svære at reparere og kan producere punktmutationer, indsættelser og deletioner fra DNA-sekvensen, såvel som kromosomale translokationer. Disse mutationer kan forårsage kræft. På grund af iboende begrænsninger i DNA-reparationsmekanismerne ville alle mennesker, såfremt de levede længe nok, før eller siden udvikle kræft. DNA-skader, som opstår naturligt på grund af normale cellulære processer, der producerer reaktive oxygenforbindelser, cellulært vands hydrolytiske aktiviteter osv., sker også ofte. Selvom de fleste af disse skader repareres, kan der i enhver celle være nogle rester af DNA-skade på trods af reparationsprocesserne. Disse tilbageværende DNA-skader ophober sig med alderen i postmitotisk pattedyrsvæv. Denne ophobning lader til at være en vigtig underliggende årsag til aldring.
Mange mutagener passer ind i rummet mellem to tilstødende basepar – dette kendes som interkalation. De fleste interkalatorer er aromatiske og plane molekyler; eksempler kunne være ethidiumbromid, akridiner, daunomycin og doxorubicin. En interkalator kan kun passe mellem basepar, hvis baserne separeres, og DNA-strengene forvrides ved at dreje dobbelthelixen ud. Dette hæmmer både transskriptionen og DNA-replikationen, hvilket skaber toxicitet og mutationer. Som resultat heraf kan DNA-interkalatorer være carcinogene, og i thalidomids tilfælde, et teratogen. Andre, såsom benzo[a]pyrenoxid og aflatoksin, danner DNA-addukter, som fremkalder fejl i replikationen. Alligevel bruges andre lignende toksiner også i kemoterapi til at sløve hurtigtvoksende kræftceller, pga. deres evne til at hæmme transskription og DNA-replikation.
Syntetisk DNA
Der er gjort forsøg med at udvide den genetiske kode med flere syntetiske bogstaver, se hachimoji DNA. Fordelene ved en udvidet kode kunne omfatte lagring af stærkt komprimerede data, dvs. en forbedret genetisk kode, samt indsigt i livets generelle kemiske forudsætninger dvs. hvad man også kunne forvente af eventuelt udenjordisk liv.
Biologiske funktioner
DNA forekommer normalt som lineære kromosomer i eukaryoter og cirkulære kromosomer i prokaryoter. Kromosomsættet i en celle udgør dens genom; menneskets genom har omkring 3 milliarder DNA-basepar arrangeret i 46 kromosomer. Informationen i DNA ligger i sekvensen af DNA-stykker, der kaldes gener. Transmission af genetisk information i gener opnås ved hjælp af komplementær baseparring. For eksempel kopieres DNA-sekvensen ved hjælp af transskription ind i en komplementær RNA-sekvens gennem tiltrækningen mellem DNA'en og de korrekte RNA-nukleotider når en celle bruger informationen i et gen. Normalt bruges denne RNA-kopi derefter til at skabe en matchende proteinsekvens ved en proces kaldet translation, som afhænger af den samme interaktion mellem RNA-nukleotider. Alternativt kan en celle simpelthen kopiere sin genetiske information ved DNA-replikation.
Gener og genomer
Genomisk DNA pakkes stramt og velordnet ved en proces kaldet DNA-kondensering for at passe ind i cellens små tilgængelige voluminer. I eukaryoter befinder DNA sig i cellekernen, såvel som små mængder i mitokondrier og grønkorn. I prokaryoter holdes DNA'en i et uregelmæssigt formet legeme i cytoplasmaen kaldet nukleoiden. Et genoms genetiske information ligger i generne, og det fuldstændige informationssæt i en organisme kaldes dens genotype. Et gen er en arvelig enhed og er en DNA-region, som påvirker en bestemt egenskab i en organisme. Gener indeholder en åben læseramme, der kan transskriberes, såvel som regulerende sekvenser såsom promotere og enhancere, som kontrollerer transskriptionen af den åbne læseramme.
I mange arter er det kun en lille fraktion af den samlede genomsekvens der koder protein. For eksempel er det kun omkring 1,5% af det menneskelige genom, som består af proteinkodende exoner, mens over 50% af menneskelig DNA består af ikke-kodende repetitive sekvenser. Det har længe været en gåde hvorfor der findes så store mængder ikke-kodende DNA og ekstraordinære forskelle i genomstørrelse (kendt som C-værdi) i eukaryotiske genomer arterne imellem. Nogle af de DNA-sekvenser, som ikke koder protein, kan dog stadig kode funktionelle ikke-kodende RNA-molekyler, som er involverede i reguleringen af genekspression.
Nogle ikke-kodende DNA-sekvenser spiller en strukturel rolle i kromosomer. Telomerer og centromerer indeholder typisk kun få gener, men er vigtige for kromosomernes funktion og stabilitet. En talstærk form for ikke-kodende DNA i mennesker er pseudogener, som er kopier af gener, der er blevet deaktiveret af mutation. Disse sekvenser er normalt kun molekylære fossiler, omend de en gang imellem kan fungere som råt genetisk materiale for skabelsen af nye gener gennem en proces kendt som genduplikation og divergens.
En del vira har DNA i deres arvemateriale – eksempelvis kopper (dobbeltstrenget) og lussingesyge (enkeltstrenget) – mens andre anvender RNA.
Transskription og translation
Et gen er en DNA-sekvens, der indeholder genetisk information og kan påvirke en organismes fænotype. Inde i et gen definerer sekvensen af baser langs en DNA-streng en messenger RNA-sekvens, som så til gengæld definerer en eller flere proteinsekvenser. Forholdet mellem geners nukleotidsekvenser og proteiners aminosyresekvenser bestemmes af reglerne for translation, der overordnet kendes som den genetiske kode. Den genetiske kode består af tre-bogstav 'ord' kaldet codoner, der dannes fra en sekvens af tre nukleotider (f.eks. ACT, CAG, TTT).
Under transskriptionen kopieres et gens codoner ind i messenger-RNA (mRNA) ved hjælp af RNA-polymerase II. Denne RNA-kopi afkodes derefter af et ribosom, som læser RNA-sekvensen ved at baseparre mRNA'et med transfer RNA (tRNA), som bærer aminosyrer. Da der er 4 baser i 3-bogstavkombinationer, er der 64 mulige codoner (43 kombinationer). Disse koder så de tyve standardaminosyrer og giver de fleste aminosyrer mere end ét muligt komplementært codon. Der findes også tre 'stop'-codoner ('nonsense'-codoner), der indikerer slutningen af kodningsregionen; disse er de tre codoner TAA, TGA og TAG, idet der ikke findes en tRNA, der er komplementær til disse.
Transskriptionen af DNA behøver dog ikke have dannelsen af mRNA, der skal translateres til et protein, som mål, da det ved transskriptionens producerede RNA i sig selv kan være målet. Dette kan f.eks. være tilfældet ved dannelsen af det omtalte tRNA (her bruges dog RNA-polymerase III frem for II) eller andre typer RNA, f.eks. precursor-miRNA, der regulerer den cellulære proteinudtrykkelse ved processen RNA-interferens.
Replikation
Celledeling er essentiel for at en organisme kan vokse, men når en celle deler sig, skal den replikere DNA'en i sit genom, så de to datterceller har samme genetiske information som deres forælder. DNA's dobbeltstrengede struktur sørger for en simpel mekanisme til DNA-replikation. Her separeres de to strenge, hvorefter hver strengs komplementære DNA-sekvens genskabes af et enzym kaldet DNA-polymerase. Dette enzym skaber den komplementære streng ved at finde den korrekte base gennem komplementær baseparring, og binder den derefter med den oprindelige streng. Da DNA-polymeraser kun kan udvide en DNA-streng i retningen 5′ til 3′, bruges andre mekanismer til at kopiere dobbelthelixens antiparallelle strenge. På denne måde bestemmer basen på den gamle streng, hvilken base der dannes på den nye streng, og cellen ender op med en perfekt kopi af sin DNA.
Ekstracellulære nukleinsyrer
Nøgen ekstracellulær DNA (eDNA), som oftest udsendes ved celledød, er næsten allestedsnærværende i miljøet. Dets koncentration i jordbunden kan være helt op til 2 μg/L, og dets koncentration i naturlige vandmiljøer kan være helt op til 88 μg/L. Der er blevet spekuleret i flere mulige funktioner, som eDNA varetager: det kan være involveret i horisontal genoverførsel; det kan levere næringsstoffer; og det kan fungere som en buffer til at rekruttere eller titrere ioner eller antibiotika. Ekstracellulær DNA opfører sig som en funktionel ekstracellulær matrixkomponent i en række bakteriearters biofilm. Det kan opføre sig som en genkendelsesfaktor til at regulere tilknytning og spredning af bestemte celletyper i biofilmen; det kan bidrage til dannelsen af biofilm; og det kan bidrage til biofilmens fysiske styrke og modstandsdygtighed over for biologisk pres.
Interaktion med proteiner
Alle DNA's funktioner afhænger af samspillet med proteiner. Disse proteininteraktioner kan være ikke-specifikke, eller proteinet kan binde sig specifikt til en enkelt DNA-sekvens. Enzymer kan også binde til DNA og af disse er polymeraserne, som kopierer DNA-basesekvensen i transskription og DNA-replikation, særligt vigtige.
DNA-bindende proteiner
Interaktion mellem DNA (orange) og histoner (blå). Disse proteiners basiske aminosyrer binder til DNA'ens sure fosfatgrupper.
Strukturelle proteiner, som binder DNA, er velkendte eksempler på ikke-specifikke interaktioner mellem DNA og protein. Inde i kromosomer holdes DNA i komplekser med strukturelle proteiner. Disse proteiner organiserer DNA'en i en kompakt struktur kaldet kromatin. I eukaryoter involverer denne struktur DNA-binding til et kompleks af små, basiske proteiner kaldet histoner, mens der er flere typer proteiner involveret i prokaryoter. Histonerne danner et pladeformet kompleks kaldet et nukleosom, som indeholder to komplette drejninger af dobbelt-strenget DNA viklet omkring dets overflade. Disse ikke-specifikke interaktioner udgøres af ionbindinger mellem basiske grupper i histonerne og sure fosfatgrupper i DNA'ens sukker-fosfat-rygrad og er derfor mestendels uafhængige af basesekvensen. Kemiske modifikationer af disse basiske grupper (der sidder på sidekæderne af aminosyrer) inkluderer methylering, fosforylering og acetylering. Disse kemiske modifikationer ændrer styrken af interaktionen mellem DNA'en og histonerne, hvilket gør DNA'en mere eller mindre tilgængelig for transskriptionsfaktorer og ændrer transskriptionshastigheden.
En særlig gruppe DNA-bindende proteiner er de DNA-bindende proteiner, som specifikt binder enkeltstrenget DNA. I mennesker er replikationsprotein A det bedst kendte eksempel fra denne familie og bruges i processer, hvor dobbelthelixen er separeret, heriblandt ved DNA-replikation, rekombination og DNA-reparation. Disse bindingsproteiner lader til at stabilisere enkeltstrenget DNA og beskytte det fra at danne hårnålsstrukturer eller blive nedbrudt af nukleaser.
I modsætning hertil er der andre proteiner, som har udviklet sig til at binde til bestemte DNA-sekvenser. De mest intensivt studerede af disse er de forskellige transskriptionsfaktorer, som er proteiner, der regulerer transskription. Hver transskriptionsfaktor binder til et bestemt sæt af DNA-sekvenser og aktiverer eller hæmmer transskriptionen af gener, som har disse sekvenser tæt på deres promotere. Transskriptionsfaktorerne gør dette på to måder. For det første kan de binde RNA-polymerasen ansvarlig for transskription, enten direkte eller gennem andre mediatorproteiner; dette lokaliserer polymerasen ved promoteren og lader den begynde transskription. Alternativt kan transskriptionsfaktorer binde enzymer, som modificerer histonerne ved promoteren. Dette ændrer på DNA-skabelonens tilgængelighed for polymerasen.
Da disse DNA-targets kan forekomme overalt i en organismes genom, kan ændringer i en type transskriptionsfaktors aktivitet påvirke tusinder af gener. Som følge heraf er disse proteiner ofte mål for de signaltransduktionsprocesser, som styrer responset på miljøforandringer eller cellulær differentiering og udvikling. Specificiteten af disse transskriptionsfaktorers interaktioner med DNA kommer af, at proteinerne har flere kontakter til DNA-basernes kant, hvilket tillader dem at "læse" DNA-sekvensen. De fleste af disse baseinteraktioner sker i den store rille, hvor baserne er mest tilgængelige.
DNA-modificerende enzymer
Nukleaser og ligaser
Nukleaser er enzymer, som skærer DNA-strenge ved at katalysere hydrolyse af fosfodiesterbindingerne. Nukleaser som hydrolyserer nukleotider fra enderne af DNA-strenge kaldes exonukleaser, mens endonukleaser skærer inde i strenge. De oftest brugte nukleaser i molekylærbiologi er restriktionsendonukleaser, som skærer DNA ved bestemte sekvenser. For eksempel genkender EcoRV-enzymet den 6-basede sekvens 5′-GATATC-3′. I naturen beskytter disse enzymer bakterier mod faginfektion ved at fordøje fag-DNA'en, når den kommer ind i den bakterielle celle, og opfører sig som en del af restriktionsmodifikationssystemet. Inden for teknologi bruges disse sekvensspecifikke nukleaser i molekylær kloning og til at tage DNA-fingeraftryk.
Enzymer kaldet DNA-ligaser kan genforbinde skårede eller brækkede DNA-strenge. Ligaser er særligt vigtige i DNA-replikation af tilbagestående strenge, da de forbinder de korte DNA-segmenter, der produceres ved replikationsgaflen til en fuldstændig kopi af DNA-skabelonen. De bruges også i DNA-reparation og genetisk rekombination.
Topoisomeraser og helicaser
Topoisomeraser er enzymer med både nuklease- og ligaseaktivitet. Disse proteiner ændrer mængden af supercoiling i DNA. Nogle af disse enzymer fungerer ved at skære DNA-helixen og lader en sektion rotere, hvorved de reducerer mængden af supercoiling; enzymet forsegler derefter DNA-bruddet. Andre typer af disse enzymer er i stand til at skære en DNA-helix og derefter sende en anden DNA-streng igennem dette brud, før det genforbinder helixen. Topoisomeraser er nødvendige for mange processer, der involverer DNA, såsom DNA-replikation og transskription.
Helicaser er proteiner, der er en form for molekylær motor. De bruger den kemiske energi i nukleosidtrifosfater, særligt ATP, til at bryde hydrogenbindinger mellem baser og strække DNA-dobbelthelixen ud i enkelte strenge. Disse enzymer er essentielle for de fleste processer hvor enzymer skal have adgang til DNA-baserne.
Polymeraser
Polymeraser er enzymer, der syntetiserer polynukleotidekæder fra nukleosidtrifosfater. Deres produkters sekvens skabes på basis af eksisterende polynukleotidkæder – kaldet "skabeloner". Disse enzymer fungerer ved at føje et nukleotid til 3′-hydroxylgruppen i enden af den voksende polynukleotidkæde gentagne gange. Som konsekvens heraf arbejder alle polymeraser i en 5′- til 3′-retning. I disse enzymers aktive sæde baseparres den nye nukleosidtrifosfat til skabelonen: Dette lader polymeraser syntetisere deres skabelons komplementære streng på korrekt vis. Polymeraser klassificeres efter den type skabelon, som de anvender.
Ved DNA-replikation tager DNA-afhængige DNA-polymeraser kopier af DNA-polynukleotidkæder. For at kunne bevare biologisk information er det essentielt, at sekvensen af baser i hver kopi er præcist komplementær til sekvensen af baser i skabelonstrengen. Mange DNA-polymeraser har en korrekturlæsende aktivitet. Her genkender polymerasen den lejlighedsvise fejl i syntesereaktionen ud fra manglen på baseparring mellem de fejlmatchede nukleotider. Hvis der opdages en fejlmatch, aktiveres en 3′ til 5′ exonukleaseaktivitet, og den ukorrekte base fjernes. I de fleste organismer fungerer DNA-polymeraser i et stort kompleks kaldet replisomet, der indeholder flere tilhørende underenheder, såsom DNA-klemmen eller helicaserne.
RNA-afhængige DNA-polymeraser er en specialiseret klasse af polymeraser, som kopierer en RNA-strengs sekvens ind i DNA. De omfatter revers transkriptase, som er et viralt enzym involveret i retroviras infektion af celler, og telomerase, som er påkrævet ved replikation af telomerer. Telomerase er en usædvanlig polymerase, fordi den indeholder sin egen RNA-skabelon som en del af sin struktur.
Transskription udføres af en DNA-afhængig RNA-polymerase, der kopierer en DNA-strengs sekvens ind i RNA. For at påbegynde transskriptionen af et gen binder RNA-polymerasen til en DNA-sekvens kaldet en promoter og separerer DNA-strengene. Derefter kopierer den gensekvensen ind i en messenger RNA-udskrift, indtil den når en DNA-region kaldet terminatoren, hvor den stopper og afkobles fra DNA'en. Ligesom det er tilfældet med menneskelige DNA-afhængige DNA-polymeraser, opererer RNA polymerase II, det enzym, der transskriberer de fleste af generne i det menneskelige genom, som en del af et stort proteinkompleks med flere regulerende og tilhørende underenheder.
Genetisk rekombination
Hollidaykorsets struktur i genetisk rekombination. De fire separate DNA-strenge er farvet rød, blå, grøn og gul.
En DNA-helix interagerer normalt ikke med andre DNA-segmenter, og i menneskeceller er de forskellige kromosomer oven i købet placeret i separate områder i cellekernen kaldet "kromosomterritorier". Denne fysiske adskillelse af forskellige kromosomer er vigtig for DNA'ens evne til at fungere som et stabilt informationsarkiv, da en af de få gange kromosomer interagerer er ved overkrydsning, der sker under kønnet formering, hvor genetisk rekombination finder sted. "Overkrydsning" betegner når to DNA-helixer brydes op, udveksler en sektion og derefter genforenes.
Rekombination lader kromosomer udveksle genetisk information og producerer nye kombinationer af gener, som øger naturlig selektions effektivitetet, og kan være vigtigt i den hurtige udvikling af nye proteiner. Genetisk rekombination kan også være involveret i DNA-reparation, særligt i cellens respons på dobbeltstrengsbrud.
Den mest almindelige form for overkrydsning er homolog rekombination, hvor de to involverede kromosomer deler meget ens sekvenser. Ikke-homolog rekombination kan være skadelig for celler, da det kan producere kromosomale translokationer og genetiske abnormiteter. Rekombinationsreaktionen katalyseres af enzymer kendt som rekombinaser, såsom RAD51. Det første skridt ved rekombination er et dobbeltstrenget brud forårsaget af enten en endonuklease eller beskadigelse af DNA'en. En række skridt delvist katalyseret af rekombinasen fører derefter til sammenføjningen af de to helixer ved mindst et Hollidaykors, hvori et segment af en enkelt streng i hver helix knyttes til den komplementære streng i den anden helix. Hollidaykorset er en tetraedrisk knudepunktsstruktur, der kan flyttes langs kromosomparret, og udskifter en streng med en anden. Rekombinationsreaktionen stoppes derefter af spaltning af knudepunktet og re-ligeringen af det frigivne DNA.
Evolution
DNA indeholder den genetiske information, der lader alle moderne levende ting fungere, vokse og reproducere. Det er dog uklart, hvor langt tilbage i livets fire milliarder år lange historie DNA har haft denne funktion, og det har været foreslået at de tidligste livsformer kan have anvendt RNA som deres genetiske materiale. RNA kan have opført sig som den centrale del af tidlig cellemetabolisme, da det både kan transmittere genetisk information og udføre katalyse som en del af ribozymer. Denne urgamle RNA-verden, hvor nukleinsyrer i så fald blev brugt til både katalyse og genetik, kan have påvirket udviklingen af den nuværende genetiske kode baseret på fire nukleotidbaser. Dette ville ske fordi antallet af forskellige baser i en sådanne organisme er en afvejning mellem et lille antal baser med bedre replikationspræcision og et stort antal baser med bedre katalytisk ribozymeffektivitet. Der er dog ingen direkte beviser på urgamle genetiske systemer, da det er umuligt at isolere DNA fra de fleste fossiler, idet DNA kun overlever i miljøet i mindre end en million år og langsomt nedbrydes til korte fragmenter i opløsning. Der er blevet fremsat påstande om ældre DNA; bedst kendt er en rapport om isoleringen af en levedygtig bakterie fra en 250 millioner år gammel saltkrystal, men disse påstande er kontroversielle.
DNA-byggesten (adenin, guanin og relaterede organiske forbindelser) kan være blevet dannet uden for Jordens atmosfære, i det ydre rum. Komplekse DNA- og RNA-forbindelser, heriblandt uracil, cytosin og thymin, er også blevet dannet i laboratorier under forhold der efterligner dem, der findes i det ydre rum, ved brug af udgangsstoffer (såsom pyrimidin) fundet i meteoritter. Pyrimidin kan, ligesom polycykliske aromatiske hydrocarboner (PAH'er), de mest carbon-rige kemiske forbindelser i universet, være blevet dannet i røde kæmper eller i kosmisk støv og gasskyer.
Anvendelse inden for teknologi
Genteknologi
Der er blevet udviklet metoder til at oprense DNA fra organismer, såsom fenol-kloroformudvinding, og til at manipulere det i laboratorier, såsom restriktionsfordøjelser og polymerasekædereaktion. Moderne biologi og biokemi gør intensivt brug af disse teknikker i rekombinant DNA-teknologi. Rekombinant DNA er menneskeskabte DNA-sekvenser, der er blevet samlet fra andre DNA-sekvenser. De kan transformeres til organismer i form af plasmider eller i passende format ved brug af en viral vektor. Genetisk modificerede organismer kan bruges til at producere produkter såsom rekombinante proteiner, til brug i biomedicinsk forskning, eller dyrkes i landbruget.
DNA-profil
Kriminalteknikere kan bruge DNA i blod, sæd, hud, spyt eller hår fundet på et gerningssted til at identificere matchende DNA fra et individ, såsom en gerningsmand. Denne proces kendes formelt som etablering af en DNA-profil, men kan også kaldes "genetiske fingeraftryk". I DNA-profiler sammenlignes længderne på variable sektioner af repetitiv DNA, såsom mikrosatellitter, mellem to mennesker. Denne metode er normalt en ekstremt troværdig teknik til at identificere matchende DNA. Identifikation kan dog være kompliceret, hvis stedet er forurenet med DNA fra flere mennesker. DNA-profiler blev udviklet i 1984 af den britiske genetiker Sir Alec Jeffreys og brugt første gang inden for kriminalteknik til at dømme Colin Pitchfork i Enderby-mordene i 1988.
Udviklingen af kriminalteknik, og evnen til nu at fremskaffe genetisk match på små prøver af blod, hud, spyt eller hår, har ført til en genundersøgelse af en række sager. Mennesker, der er anklaget for en alvorlig forbrydelse, kan blive afkrævet en DNA-prøve til sammenligning. I Danmark har et af de mest notable eksempler på en sag, hvor DNA-profil var af afgørende betydning, været ved efterforskningen af de drab og voldtægter, der blev begået af Marcel Lychau Hansen, bedre kendt som "Amagermanden". Det mest åbenlyse forsvar imod kriminaltekniske DNA-matches er at påstå at der er blevet byttet rundt på beviser. Dette har resulteret i omhyggelige og strenge håndteringsprocedurer i alle nye sager.
DNA-profiler bruges også til at identificere ofre for hændelser med mange omkomne, såvel som til at identificere lig eller kropsdele i alvorlige ulykker og sågar til at identificere individuelle ofre i massegrave – ved at sammenligne med familiemedlemmer.
DNA-profiler bruges også til faderskabstests for at afgøre, hvorvidt en person er biologisk forælder eller bedsteforælder til et barn med en sandsynlighedsgrad på 99,99% for, hvorvidt den angivelige forælder er biologisk beslægtet med barnet. Normale DNA-sekventeringsmetoder sker efter fødslen, men der findes nye metoder, hvorved man kan teste for faderskab mens moderen stadig er gravid.
DNA-enzymer eller katalytisk DNA
Deoxyribozymer, også kaldet DNAzymer eller katalytisk DNA, blev opdaget i 1994. Det er for det meste enkeltstrengede DNA-sekvenser, der er isoleret fra en stor pulje af tilfældige DNA-sekvenser gennem en kombineret tilgang kaldet in vitro-selektion eller SELEX. DNAzymer katalyserer en række kemiske reaktioner, heriblandt RNA/DNA-spaltning, RNA/DNA-ligering, aminosyrefosforylering/defosforylering, o.a. DNAzymer kan øge hastigheden af kemiske reaktioner op til 100.000.000.000 gange hastigheden af den ukatalyserede reaktion. Den mest studerede klasse af DNAzymer er RNA-spaltende DNAzymer, som er blevet brugt til opdagelse af forskellige metalioner og til at designe terapeutiske midler. Der er fundet flere metalspecifikke DNAzymer, heriblandt GR-5-DNAzymet (bly-specifikt), CA1-3-DNAzymet (kobber-specifikt), 39E-DNAzymet (uranyl-specifikt) og NaA43-DNAzymet (natrium-specifikt).
Bioinformatik
Bioinformatik involverer udviklingen af teknikker til at opbevare, data mine, søge i og manipulere biologiske data, heriblandt DNA-sekvensdata. Dette har ført til vidt anvendte fremskridt inden for datalogi, særligt string-searching-algoritmer, maskinelæring og databaseteori. String-searching eller matchingalgoritmer, som genkender en bogstavsekvens inde i en større sekvens af bogstaver, blev udviklet til at søge efter bestemte nukleotidsekvenser. DNA-sekvensen bliver sammenstillet med andre DNA-sekvenser for at identificere homologe sekvenser og lokalisere de specifikke mutationer, der gør dem specielle. Disse teknikker, særligt multiple sekvenssammenstillinger, bruges til at studere fylogenetiske forhold og proteinfunktioner. Datasæt, der repræsenterer hele genomers DNA-sekvenser, såsom de der er produceret af Human Genome Project, er svære at bruge uden de annoteringer, der identificerer generne og de regulerende elementers beliggenhed på hvert kromosom. DNA-sekvensregioner, der har de karakteristiske mønstre, som associeres med protein- eller RNA-kodende gener, kan identificeres ved genfindende algoritmer, som tillader forskere at forudsige tilstedeværelsen af bestemte genprodukter og deres mulige funktioner i en organisme, selv før de er blevet isoleret eksperimentelt. Hele genomer kan også sammenlignes, hvilket kan skabe klarhed omkring en bestemt organismes evolutionære historie og tillade undersøgelsen af komplekse evolutionære begivenheder.
DNA-nanoteknologi
DNA-nanoteknologi anvender DNA's og andre nukleinsyrers unikke molekylære genkendelsesegenskaber til at skabe selvsamlende forgrenede DNA-komplekser med nyttige egenskaber. DNA bruges således som et strukturelt materiale snarere end som en bærer af biologisk information. Dette har ført til skabelsen af to-dimensionelle periodiske gitre (der begge er flise-baserede og anvender "DNA-origami"-metoden) såvel som tredimensionelle strukturer i form af polyedre. Nanomekaniske enheder og algoritmisk selv-samling er også blevet demonstreret, og disse DNA-strukturer er blevet anvendt som skabeloner for arrangeringen af andre molekyler såsom guldnanopartikler og streptavidin-proteiner.
Historie og antropologi
Fordi DNA undergår mutationer over tid, som derefter nedarves, indeholder det historisk information, og ved at sammenligne DNA-sekvenser kan genetikere udlede organismers evolutionære historie, deres fylogeni. Feltet fylogenetik er et vigtigt værktøj inden for evolutionsbiologi. Hvis der sammenlignes DNA-sekvenser inden for samme art, kan populationsgenetikere lære om en bestemt populations historie. Dette kan bruges i studier af alt fra økologisk genetik til antropologi; for eksempel benyttes DNA-beviser til at forsøge at identificere Israels ti forsvundne stammer.
Informationslagring
I en rapport udgivet i Nature i januar 2013 foreslog forskere fra European Bioinformatics Institute og Agilent Technologies en mekanisme til at benytte DNA's evne til at kode information som en måde at lagre digitale data. Gruppen var i stand til at kode 739 kilobyte data ind i DNA-kode, syntetisere den faktiske DNA og derefter sekventere DNA'en og afkode informationen tilbage til dens oprindelige form, med 100% nøjagtighed. Den kodede information bestod af tekst- og lydfiler. Et tidligere eksperiment blev udgivet i august 2012, udført af forskere ved Harvard University, hvor man kodede teksten til en 54.000 ord lang bog ind i DNA.
DNA-forskningens historie
DNA blev identificeret og isoleret for første gang af den schweiziske læge Friedrich Miescher, som i 1869 opdagede en mikroskopisk substans i materie fra kasserede kirurgibandager. Da det var placeret i cellernes kerner (latin: nukleus, flertal nuklei) kaldte han det "nuklein".
I 1878 isolerede Albrecht Kossel ikke-protein-komponenten af "nuklein", nukleinsyre, og isolerede senere dets fem primære nukleobaser. I 1919 identificerede Phoebus Levene de grundlæggende sukker- og fosfat-nukleotidenheder. Levene foreslog, at DNA bestod af en streng af nukleotidenheder, der er forbundet via fosfatgrupperne. Levene troede, at kæden var kort, og at baserne blev gentaget i en fast rækkefølge. I 1937 producerede William Astbury de første røntgendiffraktionsmønstre, der viste, at DNA har en regelmæssig struktur.
I 1927 foreslog Nikolai Koltsov, at nedarvede egenskaber blev nedarvet gennem et "enormt arveligt molekyle" bestående af "to spejlede strenge, der ville replikere på en semi-konservativ måde ved at bruge hver streng som en skabelon". I 1928 opdagede Frederick Griffith i sit eksperiment, at træk fra den "glatte" form for Pneumococcus kunne overføres til den "ru" form af den samme bakterie ved at blande dræbte "glatte" bakterier med levende "ru" former. Dette system gav den første klare indikation af, at DNA bærer på genetisk information – Avery-MacLeod-McCarty-eksperimentet – da Oswald Avery, sammen med kollegaerne Colin MacLeod og Maclyn McCarty, identificerede DNA som det transformerende princip i 1943. DNA's rolle i arv blev bekræftet i 1952, da Alfred Hershey og Martha Chase i Hershey-Chase-eksperimentet påviste, at DNA er T2 fagens genetiske materiale.
I 1953 foreslog James Watson og Francis Crick det, der nu er accepteret som den første korrekte dobbelthelix-model af DNA-strukturen, i tidsskriftet Nature. Deres dobbeltheliske, molekylære DNA-model var dengang baseret på et enkelt røntgendiffraktionsbillede (kaldt "Foto 51") taget af Rosalind Franklin og Raymond Gosling i maj 1952, såvel som informationen om, at DNA-baserne er parrede – også opnået gennem privat kommunikation fra Erwin Chargaff i de tidligere år.
Eksperimentelt bevis til støtte for Watson og Cricks model blev udgivet i en serie af fem artikler i den samme udgave af Nature. Ud af disse var Franklin og Goslings rapport den første udgivelse af deres egne røntgendiffraktionsdata og originale analyse, som delvist understøttede Watson og Cricks model; denne udgave indeholdt også en artikel om DNA-strukturen af Maurice Wilkins og to af hans kollegaer, hvis analyse og in vivo B-DNA røntgenmønstre også understøttede tilstedeværelsen in vivo af dobbelthelix-DNA-konfigurationer som foreslået af Crick og Watson. I 1962, efter Franklin's død, blev Watson, Crick og Wilkins i fællesskab tildelt Nobelprisen i fysiologi eller medicin (nobelpriser tildeles kun levende personer). Der er fortsat debat omkring, hvem der bør tilskrives opdagelsen.
I en indflydelsesrig præsentation i 1957 forklarede Crick molekylærbiologiens centrale dogme, som forudsagde forholdet mellem DNA, RNA og proteiner, og formulerede "adaptorhypotesen". Den endelige bekræftelse af replikationsmekanismen, der blev antydet af dobbelthelix-strukturen, fulgte i 1958 i form af Meselson-Stahl-eksperimentet. Yderligere arbejde af Crick og kollegaer viste, at den genetiske kode blev baseret på ikke-overlappende basetripletter, kaldet codoner, hvilket gjorde Har Gobind Khorana, Robert W. Holley og Marshall Warren Nirenberg i stand til at dechifrere den genetiske kode. Disse fund kom til at repræsentere molekylærbiologiens fødsel.
Se også
CRISPR
eDNA, Miljø-DNA
Det molekylære ur
DNA-vaccine
Hachimoji DNA
Referencer
Yderligere læsning
Judson, Horace F. 1979. The Eighth Day of Creation: Makers of the Revolution in Biology. Touchstone Books, . 2nd edition: Cold Spring Harbor Laboratory Press, 1996 paperback: .
Micklas, David. 2003. DNA Science: A First Course. Cold Spring Harbor Press: .
, first published in October 1974 by MacMillan, with foreword by Francis Crick;the definitive DNA textbook,revised in 1994 with a 9-page postscript.
Rosenfeld, Israel. 2010. DNA: A Graphic Guide to the Molecule that Shook the World. Columbia University Press: .
Schultz, Mark and Zander Cannon. 2009. The Stuff of Life: A Graphic Guide to Genetics and DNA. Hill and Wang: .
Watson, James. 2004. DNA: The Secret of Life. Random House:
Eksterne henvisninger
En oversigt på dansk til det molekylære grundlag for den moderne genteknologi. Biotech Academy
DNA from the beginning
17 April, 2003, BBC News: Most ancient DNA ever?
18 February, 2004, BBC News: Human genome data to be released
12 May, 2004, BBC News: 'Junk' throws up precious secret Citat: "..."It is very lucky that entire genomes were mapped, as this work is showing." He added: "I think other bits of 'junk' DNA will turn out not to be junk. I think this is the tip of the iceberg, and that there will be many more similar findings."..."
Lov om oprettelse af et centralt dna-profilregister
DNA = Det Nedarves Altsammen? | Kristeligt Dagblad
DNA-analyser afslører: Mindst 11 ulve i Danmark. Videnskab.dk
Biologi
Bioteknologi
Genetik
Liv
Nukleinsyrer
Biometri
Kvælstofforbindelser | danish | 0.432438 |
smallest_genome/Porcine_circovirus.txt |
Porcine circovirus (PCV) is a group of four single-stranded DNA viruses that are non-enveloped with an unsegmented circular genome. They are members of the genus Circovirus that can infect pigs. The viral capsid is icosahedral and approximately 17 nm in diameter.
PCVs are the smallest viruses replicating autonomously in eukaryotic cells. They replicate in the nucleus of infected cells, using the host polymerase for genome amplification.
PCV-2 causes Porcine circovirus associated disease or postweaning multisystemic wasting syndrome (PMWS). An effective vaccination is now available. Fort Dodge Animal Health (Wyeth) launched the first USDA approved vaccine in 2006, containing an inactivated virus (ATCvet code: QI09AA07 (WHO)).
Classification[edit]
Three strains of PCV are known as of 2018:
PCV-1 (first identified in 1974) readily infects, but is not known to cause disease in swine.
PCV-2 (first isolated in 1997) causes PMWS, which over time results in significant depletion of lymphocytes; postmortem examination of diseased animals reveals enlarged lymph nodes and abnormal lung tissue. However, viral infection by itself tends to cause only mild disease, and co-factors such as other infections or immunostimulation seem necessary for development of severe disease. For example, concurrent infection with porcine parvovirus or PRRS virus, or immunostimulation lead to increased replication of PCV-2 and more severe disease in PCV-2-infected pigs.
PCV-3 (first described in 2015) causes a wide range of problems, and may be widespread among pigs.
PCV-1 and PCV-2 show a high degree of sequence identity and a similar genomic organisation; nevertheless, the basis of the distinct pathogenicity has not yet been unravelled. The organization for PCV-3 is similar, but the sequence identity is much lower.
Genome[edit]
Genome map of PCV-1 (identical with PCV-2)
”Melting Pot” quadruplet formation
PCV's genome is one of the simplest of all viruses, requiring only a capsid protein (ORF2) and two replicase proteins (ORF1) in order to replicate and produce a functional virus. Due to the simplicity of PCV, it must rely heavily on the host's cellular machinery to replicate. The origin of replication is located on a small octanucleotide stem-loop that is flanked by palindromic repeats, with the ORF's being located head-to-head on both sides of the Ori. Specifically, ORF1 is located clockwise and ORF2 is located counterclockwise of the Ori.
The two replicase enzymes that are created from ORF1, Rep and Rep', are conserved between the two types of PCV, and are part of the early phase of the virus. The replicases differ in that Rep is the full ORF1 transcript of 312 amino acids, whereas Rep' is a truncated form of ORF1 as a result of splicing and is only 168 amino acids in length. The promoter for rep (Prep) contains an Interferon-Stimulated Response Element (ISRE) that suggests Rep and Rep' are regulated by cytokine involvement, and is probably a means for the virus to overcome the host's immune responses to infection. Rep and Rep' form a dimer that binds to two hexameric regions adjacent to the stem-loop, H1 and H2, which is required for replication. When the dimer binds to this region, the replicases cleave the loop region of the stem-loop and remain covalently bound to the H1 and H2 regions of the DNA, which becomes the 5' end of the DNA. The newly formed 3'OH end forms a primer using host RNA polymerase, which is then used by the host's DNA polymerase to begin transcription of the viral DNA via rolling circle replication. After the complementary DNA strand has been created, the stem region of the stem-loop forms a loose, non-hydrogen bonded, quadruplet DNA structure. This loosely associated structure can form short lived DNA-trimers which forms two templates for replication, as well as maintaining the nucleic integrity of the stem region of the stem-loop. The termination of the replication sequence has not been identified, yet, though there is evidence supporting that Rep also represses its own promoter, Prep.
The ORF2 region encodes the capside protein Cap (aka CP), which differs slightly between PCV-1 and PCV-2. This variation within PCV may explain why PCV-1 is non-pathogenic, while PCV-2 is pathogenic. The promoter for this protein is located within ORF1, within the site where Rep' is truncated, and is splice from the same exon to the starting point of the ORF2 coding region and expressed during both early and late phases. This is the immunogenic region of the virus and is the primary area of research for creating a vaccine to treat PMWS.
There is a third gene encoded in the opposite orientation to ORF1 in the genome. This gene is transcribed and is an essential gene involved in viral replication.
Size[edit]
Porcine circovirus is a replicating entity with one of the smallest DNA strands consisting of a simple loop of DNA.
The DNA sequence for Porcine circovirus type 2 strain MLP-22 is 1726 base pairs long.
Entry[edit]
PCV infects a wide variety of cell types, including hepatocytes, cardiomyocytes, and macrophages. However, until recently, it was unknown exactly how attachment and entry into these cells was achieved. Research has shown that PCV utilizes clathrin-mediated endocytosis to enter the cell, though it's stipulated that there may still be other factors that haven't been identified. Once endocytosed, the endosome and lysosome formation causes an acidic pH shift, which allows ATP-driven uncoating of the virus and allows it to escape the endosomes and lysosomes. After the virus escapes the endosomes and lysosomes, it travels to the nucleus through unknown means.
Escape[edit]
Besides ORF1 and ORF2, there is also an ORF3 which is not necessarily required for PCV to survive within the host. Research has shown that the protein coded in ORF3 can modulate the host cell's cell-division cycle and cause cell-mediated, virus-induced apoptosis. Using a yeast two-hybrid screening system of ORF3 against the porcine cDNA library indicated that the ORF3 protein interacts with the porcine pPirh2, which is an E3 ubiquitin ligase. This E3 ubiquitin ligase normally interacts with p53 during the cell division cycle and prevents it from halting the cell division cycle at S-phase. However, ORF3 also interacts with pPirh2 at the same region as p53 and causes an upregulation of p53 expression. This increase in p53 stops the cell division cycle and the result of this is p53 mediated apoptosis, which releases PCV into the extracellular environment.
Contamination in human vaccine[edit]
On March 22, 2010, the U.S. Food and Drug Administration (FDA) recommended suspending the use of Rotarix, one of two vaccines licensed in the United States against rotavirus, due to findings of viral DNA contamination. Follow-up work by GlaxoSmithKline confirmed the contamination in working cells and the viral "seed" used in Rotarix production, also confirming the material was likely present since the early stages of product development, including the clinical trials for FDA approval.
Testing of the other licensed vaccine against rotavirus infection, RotaTeq, also detected some components of both PCV-1 and PCV-2. Porcine circovirus 1 is not known to cause disease in humans or other animals.
As of June 8, 2010, the FDA has, based on a careful review of a variety of scientific information, determined it is appropriate for clinicians and public health professionals in the United States to use both Rotarix and RotaTeq vaccine.
See also[edit]
Animal virology | biology | 1053412 | https://sv.wikipedia.org/wiki/Papillomvirus | Papillomvirus | Papillomvirus (ibland papillomavirus) är en mångfaldig familj av så kallade nakna och parasiterande dubbelsträngade DNA-virus vars värdar sträcker sig från fåglar och reptiler till däggdjur och människor. Virusen klassificeras baserat på värdart, vävnadsspecificitet, histologi och gensekvens. Papillomvirus som infekterar människor kallas humant papillomvirus (HPV).
Virusfamiljens evolutionära framgång och stora variation kopplas till en för virusen lyckad samevolution med deras värdar. Varje typ av papillomvirus är generellt sett artspecifik och dessutom ofta vävnadsspecifik, vilket innebär att typerna har evolutionära nischer där risken för konkurrens minskas. Virusen lyckats hålla sig ”före” sina värdar eftersom de molekylärt evolverar snabbare än sin värdart.
Papillomvirus infekterar olika typer av epitelceller och kan orsaka vårtor eller benigna tumörer. De kan även ligga latenta i värdceller utan att orsaka symptom. Vissa typer av papillomvirus klassificeras däremot som högrisktyper och kan orsaka cancer, exempelvis humant papillomvirus av typ 16 och 18.
Taxonomi
Papillomaviridae-familjen omfattar 53 släkten som delas in i två underfamiljer: Firstpapillomavirinae och Secondpapillomavirinae. Det som ytterst skiljer släktena är faktorer som olikheter inom genomen, värdorganismer, vävnadspecificitet och histologi.
Papillomvirus som tillhör underfamiljen Firstpapillomavirinae har amnioter som värdar. Virus inom underfamiljen har koden för de väsentliga virala proteinerna (E1, E2, L1 och L2) samt minst ett accessoriskt protein (E5, E6 eller E7) i sin arvsmassa.
Underfamiljen Secondpapillomavirinae har endast ett beskrivet virus och har isolerats hos en fisk. Det är det minsta papillomviruset, och arvsmassan består endast av de väsentliga virala proteinerna (E1, E2, L1 och L2).
De första papillomvirusen som beskrevs hittades hos däggdjur (framför allt hos kaniner, nötkreatur och i vårtor hos människa). Virusen fick sina engelska namn efter sin värdart: exempelvis cottontail rabbit papillomavirus (CRPV), bovine papillomavirus (BVP) och human papillomavirus (HPV). Vid upptäckter av fler typer av viruset hos en och samma art adderades ett nummer efter dess namn och förkortning: exempelvis human papillomavirus 1 (HPV1).
Humant papillomvirus
Humant papillomvirus, HPV, är en smittsam virusinfektion som överförs sexuellt från en individ till en annan vid sexuella kontakter. Cirka 70 procent av män och kvinnor av den vuxna populationen i världen är smittade med HPV-infektioner. HPV finns i många typer, man har identifierat nära 200 HPV-typer som infekterar människor. Till exempel kan HPV-infektioner drabba epitelcellerna i öppningen av urinvägarna som ombildas till cancerceller i livmoderhalsen, vilket kan resultera i livmoderhalscancer. 90 procent av alla cervixcancerfall tros vara orsakade av HPV-infektioner, och HPV kan även orsaka andra cancerformer i tonsiller, vulva, vagina, anus och penisen.
Papillomvirus och cancer hos människor
De flesta HPV-infektioner orsakar en mild sjukdom eller helt symptomfria infektioner. Cancer räknas inte som ett typiskt resultat av infektion av papillomvirus, utan förekommer endast sällsynt och då med specifika typer av papillomvirus. Hos människan är humant papillomvirus (HPV) 6 och 11 förknippade med cancerrisk. Båda dessa virus kännetecknas av genitala infektioner i form av vårtor. Från infektion kan de ligga vilande i många år i hud eller slemhinna innan de aktiveras och då leda till genitala vårtor eller cervixdysplasi (en form av pre-cancer i livmodern orsakad av okontrollerad celltillväxt). Vissa HPV-typer har onkogen potential (kan orsaka cancer) som HPV-16 och HPV-18 vilka båda är förknippade med cancer i livmoderhalsen.
Utvecklingen av cancerogen papillomvirusinfektion tar vanligtvis flera år. Papillomvirus har associerats med utveckling av olika cancerformer såsom cervixcancer, peniscancer och oral cancer.
Livmoderhalscancer
Humant papillomvirus HPV är en viktig orsak till utveckling av livmoderhalscancer, då infektion i sällsynta fall kan leda till onormal celltillväxt och cancer, ibland även med förmågan att metastasera sig till andra delar av kroppen. HPV16 och HPV18 utgör tillsammans cirka 70 procent av fallen av HPV-inducerad cancer och HPV31 och HPV41 utgör cirka 10 procent av fallen; resterande 20 procent orsakas av andra HPV-typer. De flesta HPV-infektionerna botas och självläker, men vissa har en persisterande förmåga som kan resultera i dysplasi och utvecklas till cancer genom inducering av onkogena transformationer där de inaktiverar tumörsuppressorgener.
Kondylom och peniscancer
Kondylom är en smittsam könssjukdom som orsakas av humant papillomvirus. Den kallas även för genital papillomvirusinfektion och är den vanligaste typen av sexuellt överförbara sjukdomar. Kondylom kan orsakas av många olika HPV-typer och symptomen varierar i intensitet och i varaktighet. Även om orsaken till peniscancer fortfarande är okänd finns en koppling med HPV: att bära HPV ökar risken att man drabbas av cancer, särskilt om man smittats med de virus som orsakar könsvårtor. Generellt, om man bär på HPV-högrisktyperna (HPV-16,18,31,59 och 66) och samtidigt är smittad med kondylom, då ökar risken att infektionen utvecklas till cancer.
Oral cancer
Oral cancer, även känd som muncancer, drabbar munhålan och svalget. HPV kan infektera munhålan och svalget vilket i sin tur kan leda till orofarynxcancer (bakdelen av svalget samt tungbasen och halsmandlarna/tonsiller). Den här typen av cancer kallas för orofaryngeal cancer. Cirka 80 procent av orofaryngeal cancer i Sverige tros bero på HPV-infektion. I likhet med cancer i könsdelarna är det främst HPV-16 och 18 som är förknippade med förhöjd cancerrisk i mun-halsregionen. Orofarynxcancer ökar i förekomst och en orsak som föreslagits är ändrade sexualvanor. Tidigare har det rapporterats att risken för HPV-infektion ökar och blir allt mer riskabel hos personer med flera sexpartners under en period, vilket ökar risken att drabbas av orofarynxcancer, särskilt hos unga män vid sexdebut och vid mer än 5 sexpartners.
Animalia papillomvirus
Papillomvirus är generellt artspecifika, men släktet har ett brett värdspektrum och har identifierats hos flera arter av ryggradsdjur, fåglar och reptiler. Störst fokus från forskningen har legat på humana papillomvirus och 193 olika HPV-typer som infekterar människor har beskrivits att jämföras med 183 virus från andra djurarter. Introduktionen av nya metoder för amplifiering och analys av viralt DNA har lett till att antalet kategoriserade varianter av animala papillomvirus ökat drastiskt.
Bovine papillomvirus – BPV
Det finns för närvarande 23 olika typer av Bovine papillomvirus (BPV) beskrivna från klövdjur. Baserat på genetiskt släktskap klassificeras de i fyra grupper. BPV utvecklar oftast godartade tumörer och orsakar inga medicinska komplikationer för värdarten. Dock kan BPV orsaka hyperplastiska hudflikar och papillom på slemhinnor, vilka kan vara potentiella kooperativa faktorer till cancer i matspjälkningskanalen och urinblåsan En studie som undersökt BPV-typer hos mjölkkor i Turkiet fann att i 35 BPV-positiva prover kunde BPV -1, -2, -3, -4, -6, -7, -9, och -10 identifieras. Tillika kunde nya förmodade typer av BPV upptäckas i proverna och möjligen kooperativa infektioner mellan de olika typerna, det antagandet behövdes styrkas med typspecifika primers. Studien har använt sig av PCR-analyser (Polymeraskedjereaktion) som ökar mängden av en viss DNA-sekvens hos viruset. Det innebär att flera typer av BPV kan infektera en och samma värdart. BPV-viruset kan också infektera hästdjur och ge upphov till fibroplastiska tumörer (sarkoider).
Exempel på papillomvirus hos djur
Evolution
Papillomvirusen är generellt artspecifika då spridningsvägen ofta sker via sexuella kontakter, vilket innebär att spridningen inte förekommer mellan arter. Det har inneburit att papillomvirus har samevolverat med sin värdart och följt med sin värdart vid artbildning. Dock råder det delade meningar kring spridningen, då vissa studier tyder på att överföringar av viruset sker mellan arter.
Oavsett har papillomviruset evolverat framgångsrikt genom många olika mekanismer, vilka har påverkat virusets omfattande fylogenetiska träd. Genom att papillomviruset har utvecklat flera ekologiska nischer för värdarter har de kunnat evolvera, dessutom har samevolution, adaptiv radiering och rekombination varit avgörande faktorer för papillomfamiljens historiska utveckling.
Evolution HPV58
I östra Asien finns det HPV-58 typer som orsakar livmoderhalscancer, de typerna är ovanliga i resten av världen. 747 varianter av HPV-58 är kända och av dessa är A1, A2, och A3 vanligast i Asien medan i Europa och Amerika domineras bilden av A2 och andra varianter än A.Om man med hjälp av fylogeni analyserar evolutionen av HPV-58 ser man att den första delningen ägde rum för cirka 478 600 år sedan. Den tidsperioden överensstämmer med artbildningen mellan homo sapiens, neandertalare och denisova. Neandertalarna kan ha burit på en tidig variant av HPV vid migrationen från Afrika. Neandertalarna levde i Europa och västra Asien och där de kommit i kontakt med moderna människan i mellanöstern. Korsning mellan parterna har medfört sexuell överföring av virus. Dagens geografiska skillnader i HPV58-förekomster hos befolkningen kan då vara ett resultat av en tidig spridning av HPV-58. I och med att papillomvirus infekterar basal lamina i epitelceller är det omöjligt att studera virus från fossil från förfäder av homininer.
Struktur
Papillomvirus är ett cirkulärt dubbelsträngat DNA-virus med en ikosaeder-formad proteinkapsel. Proteinkapseln innehåller en kopia av arvsmassan som är sammanpackad med associerade histonproteiner. Proteinkapseln saknar lipidmembran och papillomviruset kategoriseras därför som ett naket virus. Proteinkapseln har en diameter på 55 nm, där utsidan av proteinkapseln består av 360 kopior av proteinet L1 format i 72 pentamerer bundet med 72 stycken L2-proteiner på insidan av kapseln. Papillomvirus har en genomsnittlig genomstorlek om 7500 stycken baspar.
Vävnadsspecificitet
Papillomvirusets målceller är de basala epitelcellerna och dessa nås normalt via små skador, så kallade mikroabrasioner, i epitelet. Infektionen sprids genom att delningen av infekterade celler, närmast basal lamina, förskjuter äldre infekterade celler mot epitelets apikala yta, varifrån de kan spridas vidare.
Livscykel
Adsorption till cellytan och passage genom cellmembranet
Vid infektion binder papillomvirus-kapsidens L1-proteiner till glukosaminoglykaner på målcellens yta, generellt till proteoglykanen heparansulfat, varpå kapsidens struktur förändras. Genom förändringen kan viruset binda till sekundära receptorer som möjliggör upptagande av viruspartikeln inuti en vesikel, genom endocytos. Förändringen innebär även att L2 proteinet får en ny form och aktiveras, troligen som ett transmembranprotein i vesikelns membran. Det aktiverade L2 proteinet interagerar med adaptorproteiner, vilka möjliggör vidaretransport i cellen.
Intracellulär transport inklusive avkapsling
Vesikeln innehållande papillomviruset smälter samman med en endosom i cellen, och i endosomens sura miljö avkapslas viruset, varpå majoriteten av L1 separeras från L2 och virusets DNA. L2 och virusets arvsmassa transporteras i sin vesikel till den cellmembrana sidan av Golgiapparaten där cellens övergång till mitos inväntas. Studier av HPV 16 indikerar att virusbärande vesiklar med L2 och virus DNA under tidig profas transporteras via cellens mikrotubuli till centrosomerna där de ackumuleras, varpå de under prometafas till metafas transporteras ut, via samma nätverk, till kromosomerna. Hur L2 och virusets DNA tar sig ur vesikeln är debatterat, men från metafas och genom resten av den mitotiska cykeln tycks L2 och virusets DNA binda till en av kromosomerna, och transporteras därmed in i dottercellens cellkärna.
Transkription, Replikation av arvsmassa
I HPV31b har RNA som tyder på transkription av de öppna läsramarna E1 och E2 har upptäckts så tidigt som 4 timmar efter att cellkärnan infekterats, och övriga läsramar tog ytterligare några timmar att transkriberas. De proteiner som resulterar från transkriptionen av E1 och E2 bildar helikaser som öppnar upp virusets DNA för replikering. E1 har även visats interagera med proteinkomplex såsom DNA-polymeras för initiering av replikation. Viruset genomgår tre omgångar av replikations-faser, den första replikationen ger ett begränsat antal kopior och sker omgående efter det att cellkärnan infekterats. Den andra replikationsfasen syftar till att upprätthålla ett konstant antal viruspartiklar per cell allteftersom de basala cellerna delar sig. Normalt upphör celldelning i celler som förskjuts uppåt i epitellagret och differentieras, men i celler infekterade med papillomvirus inhiberas tumörsuppressorgener, såsom p53, vilket innebär att cellerna fortsätter att dela sig även när de närmar sig epitelets yta. Den tredje fasen sker då i de differentierade celler som förskjutits uppåt i vävnaden, här ökar det relativa antalet förekommande virala DNA per värdcell drastiskt, med upp till flera tusen per cell.
Kapsidsyntes och spridning av nya viruspartiklar
Kapsidproteinet L2 har visats syntetiseras innan L1 och de två proteinerna transporteras in i cellkärnan oberoende av varandra, varpå kapsiden bildas kring viruset när proteinerna väl är närvarande. Kapsiderna “mognar” långsammare än kapsiderna hos liknande virus och det spekuleras att detta beror på att papillomvirus har en relativt långsam livscykel till följd av sitt behov av dels basala odifferentierade epitelceller, för att möjliggöra infektion, dels differentierade, mogna och ytliga epitelceller, för att kunna spridas utan att upptäckas av cellens immunsystem.
Genetisk organisation och genuttryck
Papillomvirusets dubbelsträngade-DNA delas in i tre regioner: en tidig (E, från engelskans ‘early’), en sen (L, från engelskans ‘late’) och en lång kontrollerad region (LCR, från engelskans ‘long controlled region’). Den tidiga regionen (E) utgör cirka 50 procent av den totala arvsmassan och kodar för sex öppna läsramar: E1, E2, E4, E5, E6 och E7 och uttrycks till sex stycken virala regulatoriska proteiner som medverkar i transkription, replikation och manipuleringen av den cellulära miljön Två andra öppna läsramar har identifierats: E3 och E8, men genetiska bevis för virusproteinerna E3- och E8 har inte bevisats och vissa medlemmar i familjen Papillom saknar öppna läsramar för E3 och E8.
Den sena regionen (L) tar upp cirka 40 procent av den totala arvsmassan och kodar för virusets två kapsidproteiner: L1 och L2, som bygger upp virusets proteinkapsel.
Den långa kontrollerande regionen (LCR) utgör cirka 10 procent av papillomvirusets genom och är lokaliserad mellan de öppna läsramarna för L1 och E6. LCR-regionen har ingen proteinkodande funktion utan utgör istället regionen för replikation samt bindningsställen för virala och cellulära transkriptionsfaktorer.
Genfunktioner hos papillomvirus
Nästan all pre-mRNA från papillomvirusets DNA innehåller exoner och introner samt stycken med mer än en läsram. Papillomvirusets DNA kodar för flera proteiner från ett kompakt genom och utnyttjar alternativ splicing för att kunna uttrycka olika typer av proteiner på ett celldifferentieringsspecifikt och tidsmässigt sätt . De virala pre-mRNA innehåller signalsekvenser som signalerar för vart specifika former av alternativ splicing kan ske för att få ut ett färdigt viralt mRNA som kodar för virusets specifika proteiner.
Om och hur proteinerna uttrycks beror på vilket släkte papillomviruset tillhör. Exempelvis så utgör E5-protein inte lika stor funktion hos humant papillomvirus som proteinet gör hos bovint papillomvirus. Det kan även skilja sig med genuttrycket mellan arter av samma släkte.
Proteiner från den tidiga regionen (E)
E1: Kodar för viralt DNA-helikas och är det enda virala enzymet hos papillomviruset. Viralt DNA-helikas är väsentligt för replikation och amplifiering av virus-DNA i cellkärnan hos infekterade celler.
E2: Kodar för ett regulatoriskt protein. Proteinet är huvudregulator i virusets livscykel och spelar en nyckelroll i transkriptionsreglering, initiering av DNA-replikation och uppdelning av virusets genom.
E4: : E4 proteinet uttrycks vid sena stadier av virusets livscykel, strax före L1 och L2. E4 proteiner uttrycks i en hög koncentration och tros underlätta en effektiv frisättning av virus från en infekterad cell och därmed bidra till virusöverföring. Den höga koncentrationen av E4 kan användas som en indikator på att det finns en aktiv virusinfektion. E4 huvudsakliga funktion hos en infekterad cell är att integrera med cellulärt keratinfilament som resulterar i amyloid-liknande fibrer och utgör en reorganisation av keratinfilamentet.
E5: E5 är ett litet hydrofobiskt transmembranprotein och proteinet kan delas in i olika klasser beroende på virusets fylogeni. E5 är det minsta onkogena proteinet hos papillomvirus och är känd för att kunna bidra till tumörprogression. E5 proteinets aktivitet är inte lika väl kategoriserad som för de onkogena E6 och E7 proteinerna, men anses vara det främsta onkogena proteinet hos Bovin papillomvirus.
E5 proteinet är svårt att detektera eftersom proteinet är extremt hydrofobiskt, lokaliseras främst i membran och endast har ett litet genuttryck vid infektion. E5 interagerar med ett antal av de cellulära proteinerna och interaktionerna är viktiga för proteinets aktivitet vid celltransformation och undvikandet av immunförsvaret. Exempelvis för att hindra tidig apoptos av en infekterad cell kan E5 nedreglera Fas-receptorer och förändra bildningen av dödsinducerande signalkomplexet (DISC) orsakad av fas-ligand-receptor. E5 orsakar en reducering av MHC-klass 1 från cellytan av att låta MHC-klass 1 ackumulera i golgiapparaten. På så vis undviks att den infekterade cellen blir upptäckt av kroppens immunförsvar.
E6: E6 är, tillsammans med E7, ett onkogent protein hos framförallt Humana papillomvirus. E6 och E7 onkogena egenskaper kommer främst genom interaktion med värdcellens regulatoriska proteinkomplex. E6 protein från HVP-16 och HPV-18 stör huvudsakligen tumörsuppressorgenen p53 normala funktioner genom att ubiquitinmarkerar p53 för nedbrytning. En nedbrytning av p53 förhindrar cellcykeln att stanna i G1-fas, vilket resulterar i att cellen går in i S-fas och börjar replikera DNA. En nedbrytning av p53 resulterar också i att cellen förhindras att gå i apoptos och gör den infekterade cellen odödlig. E6 proteinet påverkar också en ökning av telomerasaktivitet för att försäkra en oändlig profilering av den infekterade cellen.
E7: Kodar för det onkogena proteinet E7 vars huvudsakliga egenskap är att orsaka en degradering av retinoblastomprotein (Rb) vilket leder till tumörprogression. E7 proteinerna har visat sig upprätthålla DNA-syntesens tillstånd i differentierade keratinocyter genom att inhibera p21 och p27, vilket resulterar i fortsatt aktivitet av cyklinberoende-kinas (cdk) och fortsatt vandring i cellcykeln trots onormala cellaktiviteter. E7 proteiner har rapporterats att underlätta integrationen för virusets DNA, orsaka avvikande mitos och upphäva cellcykelns kontrollsystem.
Proteiner från den sena regionen (L)
Papillomvirusets kapselprotein L1 och L2 är syntetiserade sent under infektionscykeln vars funktion är att inkapsla papillomvirusets cirkulära, dubbelsträngade DNA-mini-kromosom.
L1: Kodar för papillomvirusets kapselprotein som utgör den yttre och därav den största delen av hela virusets proteinkapsel. L1-proteiner kan spontant montera sig själv till en virusliknande partikel (VLP) utan hjälp från assisterande molekyler. Ytepitoper från L1-proteinet har visat sig vara igenkänningsbara för lymfocyter från kroppens specifika immunförsvar. Upptäckten av ytepitoperna lade grunden för utvecklingen av dagens vaccin mot de cancerframkallande HPV 16 och 18. L1 proteinet har en betydande roll för initiering av infektion av värdcell då proteinet kan integrera med heparansulfat kolhydrater hos plasmamembranets proteoglykaner.
L2: Kodar för det andra kapselproteinet: L2. L2 kan inte, som L1, spontant montera sig själv till en virusliknande partikel men kan bli upptagen när den uttrycks samtidigt med L1 till att bilda virusets proteinkapsel. L2 proteinet är för det mesta begravd under kapsidytan hos mogna papillomvirus, men kan exponera regioner av proteinet vid initiering av infektion via integration mellan L1 och proteoglykaner. Vid exponering kan L2 klyvas av enzymet furin från den extracellulära miljön. Klyvningen av L2 tros vara orsaken till att L2 senare kan integrera med en inträdesreceptor och integrationen mellan receptor och L2 möjliggör virusets entré in i cellen som infekteras.
Referenser
Virus | swedish | 0.483347 |
smallest_genome/genome.txt | Skip to main content
[ England ](https://www.england.nhs.uk/)
[ National Genomics Education Programme | GeNotes
](https://www.genomicseducation.hee.nhs.uk/)
Search
Results for **{phrase}** ( **{results_count}** of **{results_count_total}** )
Displaying **{results_count}** results of **{results_count_total}**
More results...
Menu
Menu Close Menu
* [ Home ](https://www.genomicseducation.hee.nhs.uk/genotes/)
* [ In the Clinic ](https://www.genomicseducation.hee.nhs.uk/genotes/in-the-clinic/)
* [ Knowledge Hub ](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/)
* [ About GeNotes ](https://www.genomicseducation.hee.nhs.uk/genotes/about/)
**Public beta** This website is in public beta – please [ give your feedback
](https://www.genomicseducation.hee.nhs.uk/genotes/beta-feedback/) .
1. [ Home ](https://www.genomicseducation.hee.nhs.uk/genotes "GeNotes")
2. [ Knowledge Hub ](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/)
3. Genome
[ Core concepts ](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-
hub//category/core-concepts)
# Genome
A genome is an organism’s complete set of genetic material. Genomics is the
study of genomes. In humans, a copy of the genome is found in nearly every
cell in the body.
* [ __ Copy URL ](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/genome/)
* [ __ Print ](javascript:window.print\(\);)
* __ Bookmark
* [ __ Email ](mailto:?subject=GeNotes — Genome&body=Genome: https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/genome/)
Page contents:
* What is a genome?
* What does a genome do?
* Where is the genome found?
* How is the genome organised?
* DNA outside the nucleus
* Key messages
* Resources
## What is a genome?
Every living organism has a [ genome
](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/genome/) ,
and most are made up of [ DNA
](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/dna/) . Some
virus genomes are made up of [ RNA
](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/rna/) ,
however. RNA is another type of nucleic acid: unlike DNA the **sugar is
ribose** , not deoxyribose.
## What does a genome do?
The genome contains both [ genes
](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/gene/) that
provide the instructions for producing [ proteins
](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/proteins/)
(about 2% of the genome) and sequences that do not directly code for proteins
(about 98% of the genome), often termed [ ‘non-coding’
](https://www.genomicseducation.hee.nhs.uk/genotes/knowledge-hub/non-coding-
dna/) .
The function of the 98% of the genome that does not code directly for proteins
is not fully understood, but parts are involved in gene regulation and others
are important for maintaining the structure of the genome. Analysing these
regions can be just as important as analysing genes when applying genomics in
clinical practice.
### How long is a genome?
The length of the genome varies between species and doesn’t necessarily
reflect the size of the organism from which it came (see figure 1). The human
genome is approximately 3 billion base pairs (3.2 to be exact) in length.
### Figure 1: Approximate genome size in different organisms
## Where is the genome found?
In organisms known as eukaryotes (which includes humans, other mammals, plants
and fungi), most of the genome is found in the nucleus of the cell (see figure
2).
### Figure 2: Cell nucleus where most of the eukaryotic genome is found
In humans and other complex multicellular organisms, a copy of the genome is
found in nearly every cell in the body. The exception to this is mammalian red
blood cells, which do not contain a genome as they do not have a nucleus or
mitochondria.
Furthermore, human reproductive cells (eggs and sperm) each contain half the
DNA from that person’s genome, which then combines to form a whole genome at
fertilisation.
## How is the genome organised?
### Chromosomes
Most of the DNA in the cell’s nucleus is organised into structures called
chromosomes. Each chromosome is a double helix of DNA, coiled and folded into
an efficient structure to fit into the nucleus.
Without this system of packaging, the DNA would not fit inside the cell. All
the DNA from a single human cell stretched out would reach approximately six
feet (180cm) in length.
In most cells there are two copies of each chromosome. The number of
chromosomes that a species has varies, and does not necessarily reflect the
size of the genome. For instance, the horse genome is organised into 32 pairs
of chromosomes and is 2.7 billion bases long, whereas the human genome is
organised into 23 pairs of chromosomes and is 3.2 billion bases long.
### Figure 3: A cell with nucleus at its centre containing chromosomes
### Human chromosomes
A human cell will usually contain 23 pairs of chromosomes. Twenty-two of these
chromosomes are called autosomes. They are numbered from 1 through to 22. The
23rd pair of chromosomes are our sex chromosomes. Females have two X
chromosomes, and males have an X and a Y chromosome.
### Figure 4: Schematic of human chromosomes showing them lined up in pairs
size order, with the sex chromosome pair last
### Homologues
The two chromosomes that make up each pair of autosomes are called homologues.
Although homologues look similar, they are not exactly the same. In humans one
chromosome of each homologous pair is inherited from the father, the other
from the mother. As females have two X sex chromosomes, these too can be
classed as homologues.
### Figure 5: A pair of homologous chromosomes, one came from the
individual’s mother, the other from their father
## DNA outside the nucleus
Cells also contain structures called mitochondria (see figure 3), which are
rather like the cell’s batteries, vital for turning energy from food into a
form that can be used by cells. There are many thousands of mitochondria
within each cell, especially in muscle and the brain.
These structures also contain a small amount of DNA, which forms less than
0.0005% of the total genome, about 16 thousand base pairs. Although it is only
a small part of the genome, it is essential: without a functional
mitochondrial genome, the cell will die.
Mitochondrial DNA is present as a complete circle, and it does not consist of
homologous pairs like nuclear DNA. Unlike nuclear DNA, which is inherited from
both the mother and the father, mitochondrial DNA is only inherited from the
mother.
## Key messages
* Every living organism has a genome.
* In humans a copy of the genome is found in nearly every cell.
* The human genome is organised into structures called chromosomes. In each cell humans have 46 chromosomes arranged into 23 pairs.
## Resources
### For clinicians
* NHS England Genomics Education Programme: [ Genomics 101: From Genes to Genome course ](https://www.genomicseducation.hee.nhs.uk/education/online-courses/genomics-101-from-genes-to-genome/)
**Tagged:** Core concepts
↑ Back to top
* **Last reviewed:** 09/05/2022
* **Next review due:** 09/05/2024
* **Authors:** Dr Ed Miller
* **Reviewers:** Dr Siobhan Simpson
#### Is this content useful?
Yes No
Report a problem with this content
Close
#### Help us improve GeNotes
Please let us know what you think about this content.
Email for non-humans
Comments
Page ref
Submit
## Useful links
* [ About GeNotes ](https://www.genomicseducation.hee.nhs.uk/genotes/about/)
* [ Give us your feedback ](https://www.genomicseducation.hee.nhs.uk/genotes/beta-feedback/)
* [ Genomics Education Programme ](https://www.genomicseducation.hee.nhs.uk/)
* [ NHS England ](https://www.england.nhs.uk/)
* [ __ Twitter ](https://twitter.com/genomicsedu "Social: Twitter")
* [ __ Facebook ](https://www.facebook.com/genomicsedu "Social: Facebook")
* [ __ YouTube ](https://www.youtube.com/user/GeneticsEducation "Social: YouTube")
* [ __ LinkedIn ](https://www.linkedin.com/company/hee-genomics-education-programme "Social: LinkedIn")
* [ __ Vimeo ](https://vimeo.com/genomicsed/ "Social: Vimeo")
## Important links
* [ NHS England Privacy policy ](https://www.england.nhs.uk/privacy-policy/)
* [ Accessibility ](https://www.genomicseducation.hee.nhs.uk/accessibility/)
© Copyright [ Genomics Education Programme
](http://genomicseducation.hee.nhs.uk)
and [ NHS England ](https://www.england.nhs.uk/) .
## Cookies on the GeNotes
We've put some small files called cookies on your device to make our site
work.
We'd also like to use analytics cookies. These send information about how our
site is used to services called Adobe Analytics, Hotjar and Google Analytics.
We use this information to improve our site.
Let us know if this is OK. We'll use a cookie to save your choice. You can [
read more about our cookies ](/genotes/cookie-policy) before you choose.
| biology | 32225 | https://sv.wikipedia.org/wiki/Genom | Genom | Genom eller arvsmassa är inom genetiken beteckningen på en organisms samtliga gener. Genomet är ärftlig information kodad i organismens fullständiga DNA-sekvens (eller vad gäller vissa virus, RNA-sekvens). Hos människan och andra högre organismer motsvarar genomet det genetiska material som finns i alla celler utom könscellerna.
Huvuddelen av genomet är uppdelat på en uppsättning kromosomer i cellkärnan. I de flesta högre organismer finns genetiskt material även utanför kromosomerna, till exempel som mitokondriellt DNA hos människan och andra eukaryoter samt i kloroplaster hos de gröna växterna. Hela genomet inklusive sådant DNA som inte finns i kromosomerna benämnes cellulärt genom, medan termen genom i sig självt oftast enbart syftar på det genetiska material som finns i kromosomerna.
Genomet hos ett antal organismer från bakterier till fiskar och människor har kartlagts. Studier om besläktade organismers genom kallas ofta genomik, för att skilja det från genetiken som oftast behandlar enskilda geners verkan eller grupper av gener.
Arbetet med att få fram den fullständiga DNA-sekvensen för människan slutfördes i Human Genome Project i slutet av 1990-talet. Identifiering av vilka delar av det mänskliga genomet som har betydelse sker bland annat inom ENCODE-projektet.
Genomet består av gener såväl som icke-kodande DNA. Varje gen utgör en DNA-sekvens, det vill säga en serie baspar, som ger upphov till ett visst protein, genom att transkriberas till budbärar-RNA. Stor del av icke-kodande DNA transkriberas också, och har betydelse för genreglering och genuttryck. En liten del av det icke-kodande DNA:et saknar eller har okänd funktion, och kallas därför skräp-DNA.
Följande tabell visar en jämförelse av storleken av genomet mätt i antal baspar hos ett antal organismer:
Det minsta kända antalet gener finns hos bakterien carsonella rudii.
Hos eukaryoter ärvs mitokontriellt DNA (mtdna) enbart från mor, mormor, och så vidare, hos människan tillbaka till Mitokondrie-Eva. Y-kromosomen är en allosom (könskromosom) hos bland annat däggdjur vars DNA (ydna) ärvs enbart från far, farfar, och så vidare, hos människan tillbaka till Y-kromosoms-Adam. Dessa gener förändras enbart genom slumpmässiga mutationer som inträffar i genomsnitt med ett visst antal generationers mellanrum (olika frekvens i olika regioner av DNA:t), vilket kan utnyttjas för att uppskatta avstånd i släktskap vid ett stort antal generationer. Individer med liknande gensekvens i dessa delar av DNA:t bildar en haplogrupp eller undergrupp. Befolkningen kan därmed delas upp i en hierarki av avgränsade mtdna-haplogrupper och i en annan hierarki av ydna-haplogrupper. Olika haplogrupper är olika vanliga bland populationer med rötter i olika regioner.
Autosomer är icke könskromosomer, vilka bildas när moderns och faderns autosomala DNA blandas slumpmässigt genom en process som kallas överkorsning, det vill säga uppdelning i delsekvenser som kopplas ihop till en ny DNA-sekvens. Även slumpmässiga mutationer kan inträffa. Individer med liknande autosomalt DNA kan grupperas genetiskt kluster.
Människans genom
Det mänskliga genomet är en komplett uppsättning av nukleinsyrasekvenser för människor, kodade som DNA i 23 kromosompar, inklusive det nukleära och det mitokondriella genomet. Det inkluderar både DNA-sekvenser som kodar för proteiner och olika typer av DNA som inte kodar för proteiner, såsom icke-translaterade RNA, strukturella och replikativa DNA-element, pseudogener och högt repetitiva sekvenser.
Människogenomet varierar mellan människor men är betydligt mindre än skillnaderna mellan människor och deras närmaste släktingar, bonoboer och schimpanser. År 2021 hade forskare fullständigt sekvenserat det kvinnliga genomet, identifierade 19 969 proteinkodande sekvenser och totalt 63 494 gener, varav de flesta var icke-kodande RNA-gener.
Människans Y-kromosom sekvenserades helt i januari 2022. Även om människogensomet har sekvenserats i sin helhet är det fortfarande inte fullständigt förstått och det återstår mycket arbete för att förklara de biologiska funktionerna hos protein- och RNA-produkterna och annotera hela sekvensen.
Se även
Gen
Genetiska koden
Genomik
Genotyp
DNA
Proteom
Mem
Genetik | swedish | 0.657104 |
smallest_genome/Human_genome.txt | The human genome is a complete set of nucleic acid sequences for humans, encoded as DNA within the 23 chromosome pairs in cell nuclei and in a small DNA molecule found within individual mitochondria. These are usually treated separately as the nuclear genome and the mitochondrial genome. Human genomes include both protein-coding DNA sequences and various types of DNA that does not encode proteins. The latter is a diverse category that includes DNA coding for non-translated RNA, such as that for ribosomal RNA, transfer RNA, ribozymes, small nuclear RNAs, and several types of regulatory RNAs. It also includes promoters and their associated gene-regulatory elements, DNA playing structural and replicatory roles, such as scaffolding regions, telomeres, centromeres, and origins of replication, plus large numbers of transposable elements, inserted viral DNA, non-functional pseudogenes and simple, highly repetitive sequences. Introns make up a large percentage of non-coding DNA. Some of this non-coding DNA is non-functional junk DNA, such as pseudogenes, but there is no firm consensus on the total amount of junk DNA.
Although the sequence of the human genome has been completely determined by DNA sequencing in 2022, it is not yet fully understood. Most, but not all, genes have been identified by a combination of high throughput experimental and bioinformatics approaches, yet much work still needs to be done to further elucidate the biological functions of their protein and RNA products (in particular, annotation of the complete CHM13v2.0 sequence is still ongoing).
Size of the human genome[edit]
In 2003, scientists reported the sequencing of 85% of the entire human genome, but as of 2020 at least 8% was still missing. In 2021, scientists reported sequencing the complete female genome (i.e., without the Y chromosome). This sequence identified 19,969 protein-coding sequences, accounting for approximately 1.5% of the genome, and 63,494 genes in total, most of them being non-coding RNA genes. The genome consists of regulatory DNA sequences, LINEs, SINEs, introns, and sequences for which as yet no function has been determined. The human Y chromosome, consisting of about 62.5 x 10 base pairs from a different cell line and found in all males, was sequenced completely in January 2022.
The current version of the standard reference genome is called GRCh38.p14 (July 2023). It consists of 22 autosomes plus one copy of the X chromosome and one copy of the Y chromosome. It contains approximately 3.1 billion base pairs (3.1 Gb or 3.1 x 10 bp). This represents the size of a composite genome based on data from multiple individuals but it is a good indication of the typical amount of DNA in a haploid set of chromosomes. Most human cells are diploid so they contain twice as much DNA.
In 2023, a draft human pangenome reference was published. It is based on 47 genomes from persons of varied ethnicity. Plans are underway for an improved reference capturing still more biodiversity from a still wider sample.
While there are significant differences among the genomes of human individuals (on the order of 0.1% due to single-nucleotide variants and 0.6% when considering indels), these are considerably smaller than the differences between humans and their closest living relatives, the bonobos and chimpanzees (~1.1% fixed single-nucleotide variants and 4% when including indels).
Molecular organization and gene content[edit]
The total length of the human reference genome does not represent the sequence of any specific individual. The genome is organized into 22 paired chromosomes, termed autosomes, plus the 23rd pair of sex chromosomes (XX) in the female and (XY) in the male. These chromosomes are all large linear DNA molecules contained within the cell nucleus. The current version of the human reference genome includes one copy of each of the autosomes plus one copy of the two sex chromosomes (X and Y). The total amount of DNA is 3.1 billion base pairs (3.1 Gb).
Protein-coding genes[edit]
Protein-coding sequences represent the most widely studied and best understood component of the human genome. These sequences ultimately lead to the production of all human proteins, although several biological processes (e.g. DNA rearrangements and alternative pre-mRNA splicing) can lead to the production of many more unique proteins than the number of protein-coding genes.
The human genome contains somewhere between 19,000 and 20,000 protein-coding genes. These genes contain an average of 10 introns and the average size of an intron is about 6 kb (6,000 bp). This means that the average size of a protein-coding gene is about 62 kb and these genes take up about 40% of the genome.
Exon sequences consist of coding DNA and untranslated regions (UTRs) at either end of the mature mRNA. The total amount of coding DNA is about 1-2% of the genome.
Many people divide the genome into coding and non-coding DNA based on the idea that coding DNA is the most important functional component the genome. About 98-99% of the human genome is non-coding DNA.
Non-coding genes[edit]
Main articles: Noncoding RNA and Non-coding DNA
Noncoding RNA molecules play many essential roles in cells, especially in the many reactions of protein synthesis and RNA processing. Noncoding RNA include tRNA, ribosomal RNA, microRNA, snRNA and other non-coding RNA genes including about 60,000 long non-coding RNAs (lncRNAs). Although the number of reported lncRNA genes continues to rise and the exact number in the human genome is yet to be defined, many of them are argued to be non-functional.
Many ncRNAs are critical elements in gene regulation and expression. Noncoding RNA also contributes to epigenetics, transcription, RNA splicing, and the translational machinery. The role of RNA in genetic regulation and disease offers a new potential level of unexplored genomic complexity.
Pseudogenes[edit]
Main article: Pseudogene
Pseudogenes are inactive copies of protein-coding genes, often generated by gene duplication, that have become nonfunctional through the accumulation of inactivating mutations. The number of pseudogenes in the human genome is on the order of 13,000, and in some chromosomes is nearly the same as the number of functional protein-coding genes. Gene duplication is a major mechanism through which new genetic material is generated during molecular evolution.
For example, the olfactory receptor gene family is one of the best-documented examples of pseudogenes in the human genome. More than 60 percent of the genes in this family are non-functional pseudogenes in humans. By comparison, only 20 percent of genes in the mouse olfactory receptor gene family are pseudogenes. Research suggests that this is a species-specific characteristic, as the most closely related primates all have proportionally fewer pseudogenes. This genetic discovery helps to explain the less acute sense of smell in humans relative to other mammals.
Regulatory DNA sequences[edit]
The human genome has many different regulatory sequences which are crucial to controlling gene expression. Conservative estimates indicate that these sequences make up 8% of the genome, however extrapolations from the ENCODE project give that 20-40% of the genome is gene regulatory sequence. Some types of non-coding DNA are genetic "switches" that do not encode proteins, but do regulate when and where genes are expressed (called enhancers).
Regulatory sequences have been known since the late 1960s. The first identification of regulatory sequences in the human genome relied on recombinant DNA technology. Later with the advent of genomic sequencing, the identification of these sequences could be inferred by evolutionary conservation. The evolutionary branch between the primates and mouse, for example, occurred 70–90 million years ago. So computer comparisons of gene sequences that identify conserved non-coding sequences will be an indication of their importance in duties such as gene regulation.
Other genomes have been sequenced with the same intention of aiding conservation-guided methods, for exampled the pufferfish genome. However, regulatory sequences disappear and re-evolve during evolution at a high rate.
As of 2012, the efforts have shifted toward finding interactions between DNA and regulatory proteins by the technique ChIP-Seq, or gaps where the DNA is not packaged by histones (DNase hypersensitive sites), both of which tell where there are active regulatory sequences in the investigated cell type.
Repetitive DNA sequences[edit]
Repetitive DNA sequences comprise approximately 50% of the human genome.
About 8% of the human genome consists of tandem DNA arrays or tandem repeats, low complexity repeat sequences that have multiple adjacent copies (e.g. "CAGCAGCAG..."). The tandem sequences may be of variable lengths, from two nucleotides to tens of nucleotides. These sequences are highly variable, even among closely related individuals, and so are used for genealogical DNA testing and forensic DNA analysis.
Repeated sequences of fewer than ten nucleotides (e.g. the dinucleotide repeat (AC)n) are termed microsatellite sequences. Among the microsatellite sequences, trinucleotide repeats are of particular importance, as sometimes occur within coding regions of genes for proteins and may lead to genetic disorders. For example, Huntington's disease results from an expansion of the trinucleotide repeat (CAG)n within the Huntingtin gene on human chromosome 4. Telomeres (the ends of linear chromosomes) end with a microsatellite hexanucleotide repeat of the sequence (TTAGGG)n.
Tandem repeats of longer sequences (arrays of repeated sequences 10–60 nucleotides long) are termed minisatellites.
Transposable genetic elements, DNA sequences that can replicate and insert copies of themselves at other locations within a host genome, are an abundant component in the human genome. The most abundant transposon lineage, Alu, has about 50,000 active copies, and can be inserted into intragenic and intergenic regions. One other lineage, LINE-1, has about 100 active copies per genome (the number varies between people). Together with non-functional relics of old transposons, they account for over half of total human DNA. Sometimes called "jumping genes", transposons have played a major role in sculpting the human genome. Some of these sequences represent endogenous retroviruses, DNA copies of viral sequences that have become permanently integrated into the genome and are now passed on to succeeding generations.
Mobile elements within the human genome can be classified into LTR retrotransposons (8.3% of total genome), SINEs (13.1% of total genome) including Alu elements, LINEs (20.4% of total genome), SVAs (SINE-VNTR-Alu) and Class II DNA transposons (2.9% of total genome).
Junk DNA[edit]
Main article: Junk DNA
There is no consensus on what constitutes a "functional" element in the genome since geneticists, evolutionary biologists, and molecular biologists employ different definitions and methods. Due to the ambiguity in the terminology, different schools of thought have emerged. In evolutionary definitions, "functional" DNA, whether it is coding or non-coding, contributes to the fitness of the organism, and therefore is maintained by negative evolutionary pressure whereas "non-functional" DNA has no benefit to the organism and therefore is under neutral selective pressure. This type of DNA has been described as junk DNA In genetic definitions, "functional" DNA is related to how DNA segments manifest by phenotype and "nonfunctional" is related to loss-of-function effects on the organism. In biochemical definitions, "functional" DNA relates to DNA sequences that specify molecular products (e.g. noncoding RNAs) and biochemical activities with mechanistic roles in gene or genome regulation (i.e. DNA sequences that impact cellular level activity such as cell type, condition, and molecular processes). There is no consensus in the literature on the amount of functional DNA since, depending on how "function" is understood, ranges have been estimated from up to 90% of the human genome is likely nonfunctional DNA (junk DNA) to up to 80% of the genome is likely functional. It is also possible that junk DNA may acquire a function in the future and therefore may play a role in evolution, but this is likely to occur only very rarely. Finally DNA that is deliterious to the organism and is under negative selective pressure is called garbage DNA.
Sequencing[edit]
Main article: Human Genome Project
The first human genome sequences were published in nearly complete draft form in February 2001 by the Human Genome Project and Celera Corporation. Completion of the Human Genome Project's sequencing effort was announced in 2004 with the publication of a draft genome sequence, leaving just 341 gaps in the sequence, representing highly repetitive and other DNA that could not be sequenced with the technology available at the time. The human genome was the first of all vertebrates to be sequenced to such near-completion, and as of 2018, the diploid genomes of over a million individual humans had been determined using next-generation sequencing.
These data are used worldwide in biomedical science, anthropology, forensics and other branches of science. Such genomic studies have led to advances in the diagnosis and treatment of diseases, and to new insights in many fields of biology, including human evolution.
By 2018, the total number of genes had been raised to at least 46,831, plus another 2300 micro-RNA genes. A 2018 population survey found another 300 million bases of human genome that was not in the reference sequence. Prior to the acquisition of the full genome sequence, estimates of the number of human genes ranged from 50,000 to 140,000 (with occasional vagueness about whether these estimates included non-protein coding genes). As genome sequence quality and the methods for identifying protein-coding genes improved, the count of recognized protein-coding genes dropped to 19,000–20,000.
In 2022 the Telomere-to-Telomere (T2T) consortium reported the complete sequence of a human female genome, filling all the gaps in the X chromosome (2020) and the 22 autosomes (May 2021). The previously unsequenced parts contain immune response genes that help to adapt to and survive infections, as well as genes that are important for predicting drug response. The completed human genome sequence will also provide better understanding of human formation as an individual organism and how humans vary both between each other and other species.
Although the 'completion' of the human genome project was announced in 2001, there remained hundreds of gaps, with about 5–10% of the total sequence remaining undetermined. The missing genetic information was mostly in repetitive heterochromatic regions and near the centromeres and telomeres, but also some gene-encoding euchromatic regions. There remained 160 euchromatic gaps in 2015 when the sequences spanning another 50 formerly unsequenced regions were determined. Only in 2020 was the first truly complete telomere-to-telomere sequence of a human chromosome determined, namely of the X chromosome. The first complete telomere-to-telomere sequence of a human autosomal chromosome, chromosome 8, followed a year later. The complete human genome (without Y chromosome) was published in 2021, while with Y chromosome in January 2022.
In 2023, a draft human pangenome reference was published. It is based on 47 genomes from persons of varied ethnicity. Plans are underway for an improved reference capturing still more biodiversity from a still wider sample.
Genomic variation in humans[edit]
Main article: Human genetic variation
Human reference genome[edit]
With the exception of identical twins, all humans show significant variation in genomic DNA sequences. The human reference genome (HRG) is used as a standard sequence reference.
There are several important points concerning the human reference genome:
The HRG is a haploid sequence. Each chromosome is represented once.
The HRG is a composite sequence, and does not correspond to any actual human individual.
The HRG is periodically updated to correct errors, ambiguities, and unknown "gaps".
The HRG in no way represents an "ideal" or "perfect" human individual. It is simply a standardized representation or model that is used for comparative purposes.
The Genome Reference Consortium is responsible for updating the HRG. Version 38 was released in December 2013.
Measuring human genetic variation[edit]
Most studies of human genetic variation have focused on single-nucleotide polymorphisms (SNPs), which are substitutions in individual bases along a chromosome. Most analyses estimate that SNPs occur 1 in 1000 base pairs, on average, in the euchromatic human genome, although they do not occur at a uniform density. Thus follows the popular statement that "we are all, regardless of race, genetically 99.9% the same", although this would be somewhat qualified by most geneticists. For example, a much larger fraction of the genome is now thought to be involved in copy number variation. A large-scale collaborative effort to catalog SNP variations in the human genome is being undertaken by the International HapMap Project.
The genomic loci and length of certain types of small repetitive sequences are highly variable from person to person, which is the basis of DNA fingerprinting and DNA paternity testing technologies. The heterochromatic portions of the human genome, which total several hundred million base pairs, are also thought to be quite variable within the human population (they are so repetitive and so long that they cannot be accurately sequenced with current technology). These regions contain few genes, and it is unclear whether any significant phenotypic effect results from typical variation in repeats or heterochromatin.
Most gross genomic mutations in gamete germ cells probably result in inviable embryos; however, a number of human diseases are related to large-scale genomic abnormalities. Down syndrome, Turner Syndrome, and a number of other diseases result from nondisjunction of entire chromosomes. Cancer cells frequently have aneuploidy of chromosomes and chromosome arms, although a cause and effect relationship between aneuploidy and cancer has not been established.
Mapping human genomic variation[edit]
Whereas a genome sequence lists the order of every DNA base in a genome, a genome map identifies the landmarks. A genome map is less detailed than a genome sequence and aids in navigating around the genome.
An example of a variation map is the HapMap being developed by the International HapMap Project. The HapMap is a haplotype map of the human genome, "which will describe the common patterns of human DNA sequence variation." It catalogs the patterns of small-scale variations in the genome that involve single DNA letters, or bases.
Researchers published the first sequence-based map of large-scale structural variation across the human genome in the journal Nature in May 2008. Large-scale structural variations are differences in the genome among people that range from a few thousand to a few million DNA bases; some are gains or losses of stretches of genome sequence and others appear as re-arrangements of stretches of sequence. These variations include differences in the number of copies individuals have of a particular gene, deletions, translocations and inversions.
Structural variation[edit]
Structural variation refers to genetic variants that affect larger segments of the human genome, as opposed to point mutations. Often, structural variants (SVs) are defined as variants of 50 base pairs (bp) or greater, such as deletions, duplications, insertions, inversions and other rearrangements. About 90% of structural variants are noncoding deletions but most individuals have more than a thousand such deletions; the size of deletions ranges from dozens of base pairs to tens of thousands of bp. On average, individuals carry ~3 rare structural variants that alter coding regions, e.g. delete exons. About 2% of individuals carry ultra-rare megabase-scale structural variants, especially rearrangements. That is, millions of base pairs may be inverted within a chromosome; ultra-rare means that they are only found in individuals or their family members and thus have arisen very recently.
SNP frequency across the human genome[edit]
Single-nucleotide polymorphisms (SNPs) do not occur homogeneously across the human genome. In fact, there is enormous diversity in SNP frequency between genes, reflecting different selective pressures on each gene as well as different mutation and recombination rates across the genome. However, studies on SNPs are biased towards coding regions, the data generated from them are unlikely to reflect the overall distribution of SNPs throughout the genome. Therefore, the SNP Consortium protocol was designed to identify SNPs with no bias towards coding regions and the Consortium's 100,000 SNPs generally reflect sequence diversity across the human chromosomes. The SNP Consortium aims to expand the number of SNPs identified across the genome to 300 000 by the end of the first quarter of 2001.
TSC SNP distribution along the long arm of chromosome 22 (from https://web.archive.org/web/20130903043223/http://snp.cshl.org/ ). Each column represents a 1 Mb interval; the approximate cytogenetic position is given on the x-axis. Clear peaks and troughs of SNP density can be seen, possibly reflecting different rates of mutation, recombination and selection.
Changes in non-coding sequence and synonymous changes in coding sequence are generally more common than non-synonymous changes, reflecting greater selective pressure reducing diversity at positions dictating amino acid identity. Transitional changes are more common than transversions, with CpG dinucleotides showing the highest mutation rate, presumably due to deamination.
Personal genomes[edit]
See also: Personal genomics
A personal genome sequence is a (nearly) complete sequence of the chemical base pairs that make up the DNA of a single person. Because medical treatments have different effects on different people due to genetic variations such as single-nucleotide polymorphisms (SNPs), the analysis of personal genomes may lead to personalized medical treatment based on individual genotypes.
The first personal genome sequence to be determined was that of Craig Venter in 2007. Personal genomes had not been sequenced in the public Human Genome Project to protect the identity of volunteers who provided DNA samples. That sequence was derived from the DNA of several volunteers from a diverse population. However, early in the Venter-led Celera Genomics genome sequencing effort the decision was made to switch from sequencing a composite sample to using DNA from a single individual, later revealed to have been Venter himself. Thus the Celera human genome sequence released in 2000 was largely that of one man. Subsequent replacement of the early composite-derived data and determination of the diploid sequence, representing both sets of chromosomes, rather than a haploid sequence originally reported, allowed the release of the first personal genome. In April 2008, that of James Watson was also completed. In 2009, Stephen Quake published his own genome sequence derived from a sequencer of his own design, the Heliscope. A Stanford team led by Euan Ashley published a framework for the medical interpretation of human genomes implemented on Quake's genome and made whole genome-informed medical decisions for the first time. That team further extended the approach to the West family, the first family sequenced as part of Illumina's Personal Genome Sequencing program. Since then hundreds of personal genome sequences have been released, including those of Desmond Tutu, and of a Paleo-Eskimo. In 2012, the whole genome sequences of two family trios among 1092 genomes was made public. In November 2013, a Spanish family made four personal exome datasets (about 1% of the genome) publicly available under a Creative Commons public domain license. The Personal Genome Project (started in 2005) is among the few to make both genome sequences and corresponding medical phenotypes publicly available.
The sequencing of individual genomes further unveiled levels of genetic complexity that had not been appreciated before. Personal genomics helped reveal the significant level of diversity in the human genome attributed not only to SNPs but structural variations as well. However, the application of such knowledge to the treatment of disease and in the medical field is only in its very beginnings. Exome sequencing has become increasingly popular as a tool to aid in diagnosis of genetic disease because the exome contributes only 1% of the genomic sequence but accounts for roughly 85% of mutations that contribute significantly to disease.
Human knockouts[edit]
In humans, gene knockouts naturally occur as heterozygous or homozygous loss-of-function gene knockouts. These knockouts are often difficult to distinguish, especially within heterogeneous genetic backgrounds. They are also difficult to find as they occur in low frequencies.
Populations with a high level of parental-relatedness result in a larger number of homozygous gene knockouts as compared to outbred populations.
Populations with high rates of consanguinity, such as countries with high rates of first-cousin marriages, display the highest frequencies of homozygous gene knockouts. Such populations include Pakistan, Iceland, and Amish populations. These populations with a high level of parental-relatedness have been subjects of human knock out research which has helped to determine the function of specific genes in humans. By distinguishing specific knockouts, researchers are able to use phenotypic analyses of these individuals to help characterize the gene that has been knocked out.
A pedigree displaying a first-cousin mating (carriers both carrying heterozygous knockouts mating as marked by double line) leading to offspring possessing a homozygous gene knockout
Knockouts in specific genes can cause genetic diseases, potentially have beneficial effects, or even result in no phenotypic effect at all. However, determining a knockout's phenotypic effect and in humans can be challenging. Challenges to characterizing and clinically interpreting knockouts include difficulty calling of DNA variants, determining disruption of protein function (annotation), and considering the amount of influence mosaicism has on the phenotype.
One major study that investigated human knockouts is the Pakistan Risk of Myocardial Infarction study. It was found that individuals possessing a heterozygous loss-of-function gene knockout for the APOC3 gene had lower triglycerides in the blood after consuming a high fat meal as compared to individuals without the mutation. However, individuals possessing homozygous loss-of-function gene knockouts of the APOC3 gene displayed the lowest level of triglycerides in the blood after the fat load test, as they produce no functional APOC3 protein.
Human genetic disorders[edit]
Further information: Genetic disorder
Most aspects of human biology involve both genetic (inherited) and non-genetic (environmental) factors. Some inherited variation influences aspects of our biology that are not medical in nature (height, eye color, ability to taste or smell certain compounds, etc.). Moreover, some genetic disorders only cause disease in combination with the appropriate environmental factors (such as diet). With these caveats, genetic disorders may be described as clinically defined diseases caused by genomic DNA sequence variation. In the most straightforward cases, the disorder can be associated with variation in a single gene. For example, cystic fibrosis is caused by mutations in the CFTR gene and is the most common recessive disorder in caucasian populations with over 1,300 different mutations known.
Disease-causing mutations in specific genes are usually severe in terms of gene function and are fortunately rare, thus genetic disorders are similarly individually rare. However, since there are many genes that can vary to cause genetic disorders, in aggregate they constitute a significant component of known medical conditions, especially in pediatric medicine. Molecularly characterized genetic disorders are those for which the underlying causal gene has been identified. Currently there are approximately 2,200 such disorders annotated in the OMIM database.
Studies of genetic disorders are often performed by means of family-based studies. In some instances, population based approaches are employed, particularly in the case of so-called founder populations such as those in Finland, French-Canada, Utah, Sardinia, etc. Diagnosis and treatment of genetic disorders are usually performed by a geneticist-physician trained in clinical/medical genetics. The results of the Human Genome Project are likely to provide increased availability of genetic testing for gene-related disorders, and eventually improved treatment. Parents can be screened for hereditary conditions and counselled on the consequences, the probability of inheritance, and how to avoid or ameliorate it in their offspring.
There are many different kinds of DNA sequence variation, ranging from complete extra or missing chromosomes down to single nucleotide changes. It is generally presumed that much naturally occurring genetic variation in human populations is phenotypically neutral, i.e., has little or no detectable effect on the physiology of the individual (although there may be fractional differences in fitness defined over evolutionary time frames). Genetic disorders can be caused by any or all known types of sequence variation. To molecularly characterize a new genetic disorder, it is necessary to establish a causal link between a particular genomic sequence variant and the clinical disease under investigation. Such studies constitute the realm of human molecular genetics.
With the advent of the Human Genome and International HapMap Project, it has become feasible to explore subtle genetic influences on many common disease conditions such as diabetes, asthma, migraine, schizophrenia, etc. Although some causal links have been made between genomic sequence variants in particular genes and some of these diseases, often with much publicity in the general media, these are usually not considered to be genetic disorders per se as their causes are complex, involving many different genetic and environmental factors. Thus there may be disagreement in particular cases whether a specific medical condition should be termed a genetic disorder.
Additional genetic disorders of mention are Kallman syndrome and Pfeiffer syndrome (gene FGFR1), Fuchs corneal dystrophy (gene TCF4), Hirschsprung's disease (genes RET and FECH), Bardet-Biedl syndrome 1 (genes CCDC28B and BBS1), Bardet-Biedl syndrome 10 (gene BBS10), and facioscapulohumeral muscular dystrophy type 2 (genes D4Z4 and SMCHD1).
Genome sequencing is now able to narrow the genome down to specific locations to more accurately find mutations that will result in a genetic disorder. Copy number variants (CNVs) and single nucleotide variants (SNVs) are also able to be detected at the same time as genome sequencing with newer sequencing procedures available, called Next Generation Sequencing (NGS). This only analyzes a small portion of the genome, around 1–2%. The results of this sequencing can be used for clinical diagnosis of a genetic condition, including Usher syndrome, retinal disease, hearing impairments, diabetes, epilepsy, Leigh disease, hereditary cancers, neuromuscular diseases, primary immunodeficiencies, severe combined immunodeficiency (SCID), and diseases of the mitochondria. NGS can also be used to identify carriers of diseases before conception. The diseases that can be detected in this sequencing include Tay-Sachs disease, Bloom syndrome, Gaucher disease, Canavan disease, familial dysautonomia, cystic fibrosis, spinal muscular atrophy, and fragile-X syndrome. The Next Genome Sequencing can be narrowed down to specifically look for diseases more prevalent in certain ethnic populations.
Prevalence and associated gene/chromosome for some human genetic disorders
Disorder
Prevalence
Chromosome or gene involved
Chromosomal conditions
Down syndrome
1:600
Chromosome 21
Klinefelter syndrome
1:500–1000 males
Additional X chromosome
Turner syndrome
1:2000 females
Loss of X chromosome
Sickle cell anemia
1 in 50 births in parts of Africa; rarer elsewhere
β-globin (on chromosome 11)
Bloom syndrome
1:48000 Ashkenazi Jews
BLM
Cancers
Breast/Ovarian cancer (susceptibility)
~5% of cases of these cancer types
BRCA1, BRCA2
FAP (hereditary nonpolyposis coli)
1:3500
APC
Lynch syndrome
5–10% of all cases of bowel cancer
MLH1, MSH2, MSH6, PMS2
Fanconi anemia
1:130000 births
FANCC
Neurological conditions
Huntington disease
1:20000
Huntingtin
Alzheimer disease - early onset
1:2500
PS1, PS2, APP
Tay-Sachs
1:3600 births in Ashkenazi Jews
HEXA gene (on chromosome 15)
Canavan disease
2.5% Eastern European Jewish ancestry
ASPA gene (on chromosome 17)
Familial dysautonomia
600 known cases worldwide since discovery
IKBKAP gene (on chromosome 9)
Fragile X syndrome
1.4:10000 in males, 0.9:10000 in females
FMR1 gene (on X chromosome)
Mucolipidosis type IV
1:90 to 1:100 in Ashkenazi Jews
MCOLN1
Other conditions
Cystic fibrosis
1:2500
CFTR
Duchenne muscular dystrophy
1:3500 boys
Dystrophin
Becker muscular dystrophy
1.5–6:100000 males
DMD
Beta thalassemia
1:100000
HBB
Congenital adrenal hyperplasia
1:280 in Native Americans and Yupik Eskimos
1:15000 in American Caucasians
CYP21A2
Glycogen storage disease type I
1:100000 births in America
G6PC
Maple syrup urine disease
1:180000 in the U.S.
1:176 in Mennonite/Amish communities
1:250000 in Austria
BCKDHA, BCKDHB, DBT, DLD
Niemann–Pick disease, SMPD1-associated
1,200 cases worldwide
SMPD1
Usher syndrome
1:23000 in the U.S.
1:28000 in Norway
1:12500 in Germany
CDH23, CLRN1, DFNB31, GPR98, MYO7A, PCDH15, USH1C, USH1G, USH2A
Evolution[edit]
Hominin timelineThis box: viewtalkedit−10 —–−9 —–−8 —–−7 —–−6 —–−5 —–−4 —–−3 —–−2 —–−1 —–0 —MiocenePliocenePleistoceneHomininiNakalipithecusSamburupithecusOuranopithecus(Ou. turkae)(Ou. macedoniensis)ChororapithecusOreopithecusSivapithecusSahelanthropusGraecopithecusOrrorin(O. praegens)(O. tugenensis)Ardipithecus(Ar. kadabba)(Ar. ramidus)Australopithecus(Au. africanus)(Au. afarensis)(Au. anamensis)H. habilis(H. rudolfensis)(Au. garhi)H. erectus(H. antecessor)(H. ergaster)(Au. sediba)H. heidelbergensisHomo sapiensNeanderthalsDenisovans ←Earlier apes←Gorilla split←Chimpanzee split←Earliest bipedal←Earliest sign of Ardipithecus←Earliest sign of Australopithecus←Earliest stone tools←Earliest sign of Homo←Dispersal beyond Africa←Earliest fire / cooking←Earliest rock art←Earliest clothes←Modern humansHominidsParanthropus(million years ago)
See also: Human evolution and Chimpanzee Genome Project
Comparative genomics studies of mammalian genomes suggest that approximately 5% of the human genome has been conserved by evolution since the divergence of extant lineages approximately 200 million years ago, containing the vast majority of genes. The published chimpanzee genome differs from that of the human genome by 1.23% in direct sequence comparisons. Around 20% of this figure is accounted for by variation within each species, leaving only ~1.06% consistent sequence divergence between humans and chimps at shared genes. This nucleotide by nucleotide difference is dwarfed, however, by the portion of each genome that is not shared, including around 6% of functional genes that are unique to either humans or chimps.
In other words, the considerable observable differences between humans and chimps may be due as much or more to genome level variation in the number, function and expression of genes rather than DNA sequence changes in shared genes. Indeed, even within humans, there has been found to be a previously unappreciated amount of copy number variation (CNV) which can make up as much as 5–15% of the human genome. In other words, between humans, there could be +/- 500,000,000 base pairs of DNA, some being active genes, others inactivated, or active at different levels. The full significance of this finding remains to be seen. On average, a typical human protein-coding gene differs from its chimpanzee ortholog by only two amino acid substitutions; nearly one third of human genes have exactly the same protein translation as their chimpanzee orthologs. A major difference between the two genomes is human chromosome 2, which is equivalent to a fusion product of chimpanzee chromosomes 12 and 13. (later renamed to chromosomes 2A and 2B, respectively).
Humans have undergone an extraordinary loss of olfactory receptor genes during our recent evolution, which explains our relatively crude sense of smell compared to most other mammals. Evolutionary evidence suggests that the emergence of color vision in humans and several other primate species has diminished the need for the sense of smell.
In September 2016, scientists reported that, based on human DNA genetic studies, all non-Africans in the world today can be traced to a single population that exited Africa between 50,000 and 80,000 years ago.
Mitochondrial DNA[edit]
The human mitochondrial DNA is of tremendous interest to geneticists, since it undoubtedly plays a role in mitochondrial disease. It also sheds light on human evolution; for example, analysis of variation in the human mitochondrial genome has led to the postulation of a recent common ancestor for all humans on the maternal line of descent (see Mitochondrial Eve).
Due to the lack of a system for checking for copying errors, mitochondrial DNA (mtDNA) has a more rapid rate of variation than nuclear DNA. This 20-fold higher mutation rate allows mtDNA to be used for more accurate tracing of maternal ancestry. Studies of mtDNA in populations have allowed ancient migration paths to be traced, such as the migration of Native Americans from Siberia or Polynesians from southeastern Asia. It has also been used to show that there is no trace of Neanderthal DNA in the European gene mixture inherited through purely maternal lineage. Due to the restrictive all or none manner of mtDNA inheritance, this result (no trace of Neanderthal mtDNA) would be likely unless there were a large percentage of Neanderthal ancestry, or there was strong positive selection for that mtDNA. For example, going back 5 generations, only 1 of a person's 32 ancestors contributed to that person's mtDNA, so if one of these 32 was pure Neanderthal an expected ~3% of that person's autosomal DNA would be of Neanderthal origin, yet they would have a ~97% chance of having no trace of Neanderthal mtDNA.
Epigenome[edit]
See also: Epigenetics
Epigenetics describes a variety of features of the human genome that transcend its primary DNA sequence, such as chromatin packaging, histone modifications and DNA methylation, and which are important in regulating gene expression, genome replication and other cellular processes. Epigenetic markers strengthen and weaken transcription of certain genes but do not affect the actual sequence of DNA nucleotides. DNA methylation is a major form of epigenetic control over gene expression and one of the most highly studied topics in epigenetics. During development, the human DNA methylation profile experiences dramatic changes. In early germ line cells, the genome has very low methylation levels. These low levels generally describe active genes. As development progresses, parental imprinting tags lead to increased methylation activity.
Epigenetic patterns can be identified between tissues within an individual as well as between individuals themselves. Identical genes that have differences only in their epigenetic state are called epialleles. Epialleles can be placed into three categories: those directly determined by an individual's genotype, those influenced by genotype, and those entirely independent of genotype. The epigenome is also influenced significantly by environmental factors. Diet, toxins, and hormones impact the epigenetic state. Studies in dietary manipulation have demonstrated that methyl-deficient diets are associated with hypomethylation of the epigenome. Such studies establish epigenetics as an important interface between the environment and the genome.
See also[edit]
Human Genome Organisation
Genome Reference Consortium
Human Genome Project
Genetics
Genomics
Genographic Project
Genomic organization
Karyotype
Low copy repeats
Non-coding DNA
Whole genome sequencing
Universal Declaration on the Human Genome and Human Rights | biology | 5284 | https://da.wikipedia.org/wiki/Gen | Gen | Et gen er en biologisk enhed for information kodet i DNA om dannelse af et biologisk molekyle.
Et individs gener kaldes arvemassen eller genomet. Ordet gen indførtes i 1909 af den danske biolog Wilhelm Johannsen. Den klassiske genetik omhandler hvordan gener nedarves, se Gregor Mendel.
Gener indeholder informationen til proteinsyntese i form af sekvensen af baser i DNA. Det kan f.eks. være informationen til fremstilling af et enzym, som f.eks. indgår i nedbrydningen af føden. Andre gener koder for andre proteiner som antistoffer og visse hormoner, transportmolekyler, enzymhæmmere, adhæsionsmolekyler, toksiner, receptorer, lectiner og mikroproteiner.
Atter andre gener koder for rRNA, tRNA og andre RNA-molekyler med forskellige regulerende funktioner.
Forskellige organismer har ikke det samme antal gener. Encellede bakteriers arvemasse har cirka 4.000 gener, en gærcelle har 6.000 gener, planter har et meget varierende antal gener, og dyr har typisk 10-100.000 gener. Mennesket har 20.344 gener der koder for proteiner.
Generne består af DNA og udgør (sammen med proteiner, bl.a. histoner) cellens kromosomer. Det sted, som et gen sidder på et kromosom, kaldes genets locus. Hvert diploid individ har to kopier af hvert gen. En kopi er arvet fra faren og en fra moren. Grundlaget for genetisk variation er, at gener forekommer i funktionelt forskellige former, som betegnes alleler. Forskelle mellem alleler reflekterer forskelle i den DNA-sekvens, som udgør genet.
Ændringer i et gen kaldes mutationer, f.eks. rækkefølgen af basene i DNAet, se f.eks. ændringen af CFTR hvor f.eks. en mangel på tre baser forårsager cystisk fibrose.
Se også
CRISPR
Genetik
Allel
Genteknologi
Arv (genetisk)
Onkogen
Eksterne henvisninger
DR's tema om gener | danish | 0.441212 |
smallest_genome/s41467021221008.txt | Skip to main content
Thank you for visiting nature.com. You are using a browser version with
limited support for CSS. To obtain the best experience, we recommend you use a
more up to date browser (or turn off compatibility mode in Internet Explorer).
In the meantime, to ensure continued support, we are displaying the site
without styles and JavaScript.
Advertisement
[
](//pubads.g.doubleclick.net/gampad/jump?iu=/285/nature_communications/article&sz=728x90&c=1266689533&t=pos%3Dtop%26type%3Darticle%26artid%3Ds41467-021-22100-8%26doi%3D10.1038/s41467-021-22100-8%26techmeta%3D15,22,23,45,90,91%26subjmeta%3D177,200,208,631,8%26kwrd%3DAgricultural+genetics,Epigenomics,Gene+regulation)
[ 
](/ncomms)
* [ View all journals ](https://www.nature.com/siteindex)
* Search
* [ Log in ](https://idp.nature.com/auth/personal/springernature?redirect_uri=https://www.nature.com/articles/s41467-021-22100-8)
* Explore content
* About the journal
* Publish with us
* [ Sign up for alerts ](https://idp.nature.com/auth/personal/springernature?redirect_uri=https%3A%2F%2Fwww.nature.com%2Fmy-account%2Falerts%2Fsubscribe-journal%3Flist-id%3D264%26journal-link%3Dhttps%253A%252F%252Fwww.nature.com%252Fncomms%252F)
* [ RSS feed ](https://www.nature.com/ncomms.rss)
1. [ nature ](/)
2. [ nature communications ](/ncomms)
3. [ articles ](/ncomms/articles?type=article)
4. article
Functional annotations of three domestic animal genomes provide vital
resources for comparative and agricultural research
[ Download PDF ](/articles/s41467-021-22100-8.pdf)
[ Download PDF ](/articles/s41467-021-22100-8.pdf)
* Article
* [ Open access ](https://www.springernature.com/gp/open-research/about/the-fundamentals-of-open-access-and-open-research)
* Published: 23 March 2021
# Functional annotations of three domestic animal genomes provide vital
resources for comparative and agricultural research
* Colin Kern 1 ,
* Ying Wang 1 ,
* Xiaoqin Xu [ ORCID: orcid.org/0000-0002-9744-1165 ](http://orcid.org/0000-0002-9744-1165) 1 ,
* Zhangyuan Pan 1 ,
* Michelle Halstead [ ORCID: orcid.org/0000-0003-0168-2704 ](http://orcid.org/0000-0003-0168-2704) 1 ,
* Ganrea Chanthavixay 1 ,
* Perot Saelao [ ORCID: orcid.org/0000-0003-1171-9187 ](http://orcid.org/0000-0003-1171-9187) 1 ,
* Susan Waters 1 ,
* Ruidong Xiang 2 , 3 ,
* Amanda Chamberlain [ ORCID: orcid.org/0000-0002-9395-1299 ](http://orcid.org/0000-0002-9395-1299) 3 ,
* Ian Korf 4 ,
* Mary E. Delany [ ORCID: orcid.org/0000-0001-9901-3597 ](http://orcid.org/0000-0001-9901-3597) 1 ,
* Hans H. Cheng 5 ,
* Juan F. Medrano [ ORCID: orcid.org/0000-0001-7113-3183 ](http://orcid.org/0000-0001-7113-3183) 1 ,
* Alison L. Van Eenennaam [ ORCID: orcid.org/0000-0003-1562-162X ](http://orcid.org/0000-0003-1562-162X) 1 ,
* Chris K. Tuggle [ ORCID: orcid.org/0000-0002-4229-5316 ](http://orcid.org/0000-0002-4229-5316) 6 ,
* Catherine Ernst [ ORCID: orcid.org/0000-0003-2833-0995 ](http://orcid.org/0000-0003-2833-0995) 7 ,
* Paul Flicek [ ORCID: orcid.org/0000-0002-3897-7955 ](http://orcid.org/0000-0002-3897-7955) 8 ,
* Gerald Quon [ ORCID: orcid.org/0000-0002-1716-0153 ](http://orcid.org/0000-0002-1716-0153) 9 ,
* Pablo Ross [ ORCID: orcid.org/0000-0002-3972-3754 ](http://orcid.org/0000-0002-3972-3754) 1 &
* …
* Huaijun Zhou [ ORCID: orcid.org/0000-0001-6023-9521 ](http://orcid.org/0000-0001-6023-9521) 1
Show authors
[ _Nature Communications_ ](/ncomms) ** volume 12 ** , Article number: 1821
( 2021 ) Cite this article
* 12k Accesses
* 87 Citations
* 12 Altmetric
* [ Metrics details ](/articles/s41467-021-22100-8/metrics)
### Subjects
* [ Agricultural genetics ](/subjects/agricultural-genetics)
* [ Epigenomics ](/subjects/epigenomics)
* [ Gene regulation ](/subjects/gene-regulation)
## Abstract
Gene regulatory elements are central drivers of phenotypic variation and thus
of critical importance towards understanding the genetics of complex traits.
The Functional Annotation of Animal Genomes consortium was formed to
collaboratively annotate the functional elements in animal genomes, starting
with domesticated animals. Here we present an expansive collection of datasets
from eight diverse tissues in three important agricultural species: chicken (
_Gallus gallus_ ), pig ( _Sus scrofa_ ), and cattle ( _Bos taurus_ ).
Comparative analysis of these datasets and those from the human and mouse
Encyclopedia of DNA Elements projects reveal that a core set of regulatory
elements are functionally conserved independent of divergence between species,
and that tissue-specific transcription factor occupancy at regulatory elements
and their predicted target genes are also conserved. These datasets represent
a unique opportunity for the emerging field of comparative epigenomics, as
well as the agricultural research community, including species that are
globally important food resources.
### Similar content being viewed by others
### [ Emx2 underlies the development and evolution of marsupial gliding
membranes
](https://www.nature.com/articles/s41586-024-07305-3?fromPaywallRec=false)
Article Open access 24 April 2024
### [ Differential selection of yield and quality traits has shaped genomic
signatures of cowpea domestication and improvement
](https://www.nature.com/articles/s41588-024-01722-w?fromPaywallRec=false)
Article 22 April 2024
### [ Evolution of tissue-specific expression of ancestral genes across
vertebrates and insects
](https://www.nature.com/articles/s41559-024-02398-5?fromPaywallRec=false)
Article 15 April 2024
## Introduction
Genetic improvement of domestic animal species has been a key driver of
reducing the environmental footprint of animal source foods, which are of
critical nutritional importance in developing countries [ 1
](/articles/s41467-021-22100-8#ref-CR1 "Adesogan, A. T., Havelaar, A. H.,
McKune, S. L., Eilittä, M. & Dahl, G. E. Animal source foods: sustainability
problem or malnutrition and sustainability solution? Perspective matters.
Glob. Food Secur. 25, 100325 \(2020\).") . Climate change and recurring and
novel pandemics, such as the current COVID-19 crisis, have unprecedented
impacts on food security which, along with the ever-growing human population
and increasing demand for food, mean that improvements in food production and
sustainability are of critical importance. Chicken, cattle, and pig are three
of the most important domestic animal species that contribute economical and
nutritionally valuable protein to global food production [ 1
](/articles/s41467-021-22100-8#ref-CR1 "Adesogan, A. T., Havelaar, A. H.,
McKune, S. L., Eilittä, M. & Dahl, G. E. Animal source foods: sustainability
problem or malnutrition and sustainability solution? Perspective matters.
Glob. Food Secur. 25, 100325 \(2020\).") . Understanding the genetic basis of
economically important complex traits in domestic animals is a primary focus
of animal agriculture, as such knowledge provides the essential basis for the
continued genetic improvement necessary to meet the projected increased demand
using fewer animals. Furthermore, these species are important for their
contributions to our understanding of evolutionary biology, human
developmental biology, disease, and clinically relevant medicine [ 2
](/articles/s41467-021-22100-8#ref-CR2 "Wallis, J. W. et al. A physical map of
the chicken genome. Nature 432, 761–764 \(2004\).") . It is widely accepted
that most of the causative genetic variants associated with complex traits are
located in non-coding genic and intergenic regions that regulate gene
expression [ 3 ](/articles/s41467-021-22100-8#ref-CR3 "Hindorff, L. A. et al.
Potential etiologic and functional implications of genome-wide association
loci for human diseases and traits. Proc. Natl Acad. Sci. USA 106, 9362–9367
\(2009\).") . Human and mouse catalogs of regulatory elements (REs) 4 , 5
, 6 , [ 7 ](/articles/s41467-021-22100-8#ref-CR7 "Maurano, M. T. et al.
Systematic localization of common disease-associated variation in regulatory
DNA. Science 337, 1190–1195 \(2012\).") have been critical for identifying
genetic variants associated with health and disease [ 8
](/articles/s41467-021-22100-8#ref-CR8 "Kundaje, A. et al. Integrative
analysis of 111 reference human epigenomes. Nature 518, 317–330 \(2015\).") ,
and the recent completion of ENCODE phase 3 has further highlighted the
importance of functional elements on evolutionary biology, human medicine, and
genotype-to-phenotype prediction [ 9 ](/articles/s41467-021-22100-8#ref-CR9
"Abascal, F. et al. Perspectives on ENCODE. Nature 583, 693–698 \(2020\).") ,
[ 10 ](/articles/s41467-021-22100-8#ref-CR10 "Gorkin, D. U. et al. An atlas of
dynamic chromatin landscapes in mouse fetal development. Nature 583, 744–751
\(2020\).") . While some studies have investigated the evolution of regulatory
sequences in non-model and non-mammalian species 11 , 12 , 13 , 14 ,
15 , 16 , [ 17 ](/articles/s41467-021-22100-8#ref-CR17 "Artemov, A. V. et
al. Genome-wide DNA methylation profiling reveals epigenetic adaptation of
stickleback to marine and freshwater conditions. Mol. Biol. Evol. 34,
2203–2213 \(2017\).") , broad questions still remain as to what extent the
epigenomic and regulatory logic is conserved, especially at large evolutionary
distances.
Here we present an eight-tissue functional annotation of the chicken, pig, and
cattle genomes as one of the pilot projects of the Functional Annotation of
Animal Genomes (FAANG) consortium [ 16 ](/articles/s41467-021-22100-8#ref-
CR16 "Foissac, S. et al. Multi-species annotation of transcriptome and
chromatin structure in domesticated animals. BMC Biol. 17, 108 \(2019\).") ,
18 , 19 , 20 , 21 , 22 , 23 , [ 24
](/articles/s41467-021-22100-8#ref-CR24 "Clark, E. L. et al. From FAANG to
fork: application of highly annotated genomes to improve farmed animal
production. Genome Biol. 21, 285 \(2020\).") . Comparative analysis of these
datasets, along with complementary datasets from the human and mouse ENCODE
projects [ 25 ](/articles/s41467-021-22100-8#ref-CR25 "Stergachis, A. B. et
al. Conservation of trans-acting circuitry during mammalian regulatory
evolution. Nature 515, 365–370 \(2014\).") , [ 26
](/articles/s41467-021-22100-8#ref-CR26 "Cheng, Y. et al. Principles of
regulatory information conservation between mouse and human. Nature 515,
371–375 \(2014\).") , find low levels of conservation in the sequence and
position of REs, especially enhancers. On the other hand, tissue-specific
patterns of transcription factor motif enrichment are highly conserved. The
functional epigenetic landscape of some REs are found to be conserved across
all five species, including chicken, and are associated with genes involved in
basic metabolic processes. Prediction of enhancer target genes further reveal
that chickens possess a reduced set of enhancers relative to mammals that
collectively regulate a similar number of genes, resulting in each chicken
enhancer being more multi-functional. These analyses are, to our knowledge,
the largest reported genome-wide comparison of REs across birds and mammals in
terms of the set of tissues and assays used, and provide a vital data resource
for the agricultural research community.
## Results
### Data overview
We performed genome-wide functional annotation using the experimental design
shown in Fig. [ 1a ](/articles/s41467-021-22100-8#Fig1) . Briefly, six
epigenetic data types were profiled in eight tissues (liver, lung, spleen,
skeletal muscle, subcutaneous adipose, cerebellum, brain cortex, and
hypothalamus) collected from sexually mature male chickens, pigs, and cattle.
The epigenetic data generated included four histone modifications (H3K4me3,
H3K27ac, H3K4me1, H3K27me3) and one DNA-binding protein (CTCF) using chromatin
immunoprecipitation followed by sequencing (ChIP-seq) [ 27
](/articles/s41467-021-22100-8#ref-CR27 "Johnson, D. S., Mortazavi, A., Myers,
R. M. & Wold, B. Genome-wide mapping of in vivo protein-DNA interactions.
Science 316, 1497–1502 \(2007\).") , [ 28 ](/articles/s41467-021-22100-8#ref-
CR28 "Barski, A. et al. High-resolution profiling of histone methylations in
the human genome. Cell 129, 823–837 \(2007\).") , and chromatin accessibility
using DNase I hypersensitive sites sequencing (DNase-seq) [ 29
](/articles/s41467-021-22100-8#ref-CR29 "Crawford, G. E. et al. Genome-wide
mapping of DNase hypersensitive sites using massively parallel signature
sequencing \(MPSS\). Genome Res. 16, 123–131 \(2006\).") in chickens and Assay
for Transposase-Accessible Chromatin using sequencing (ATAC-seq) [ 30
](/articles/s41467-021-22100-8#ref-CR30 "Buenrostro, J. D., Giresi, P. G.,
Zaba, L. C., Chang, H. Y. & Greenleaf, W. J. Transposition of native chromatin
for fast and sensitive epigenomic profiling of open chromatin, DNA-binding
proteins and nucleosome position. Nat. Methods 10, 1213–1218 \(2013\).") in
cattle and pigs. Transcriptome sequencing was also performed to correlate gene
expression with regulatory region activity.
**Fig. 1: ChromHMM integrates ChIP-seq data to predict chromatin states.**
[ 
](/articles/s41467-021-22100-8/figures/1)
**a** Experimental design schematic for the study. **b** Emission
probabilities of the 14-state ChromHMM model. **c** Percent of the genome
annotated with any functional state (any state except “Low Signal”). **d** The
number of regulatory elements identified in each species, separated by TSS
proximal (within 2 kb of annotated TSS), genic (overlapping annotated gene
body), and intergenic. **e** Percentage of regulatory elements that co-
occurred with open chromatin in the tissues in which they were active.
[ Full size image ](/articles/s41467-021-22100-8/figures/1)
A total of 240 ChIP-seq libraries were generated and sequenced to produce
5,021,232,911 reads from chicken samples, 4,281,659,559 from pig samples, and
6,813,035,002 from cattle samples. Additionally, 15 DNase-seq libraries
totaling 805,274,643 reads were produced as well as 1,038,779,370 ATAC-seq
reads from 16 pig samples and 1,190,252,653 ATAC-seq reads from 15 cattle
samples. The data has been deposited in public repositories
(https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE158430) and a UCSC
track hub is available to view the chromatin state prediction, predicted
enhancer–gene pairs, and assay read depth ( [
http://farm.cse.ucdavis.edu/~ckern/FAANG/
](http://farm.cse.ucdavis.edu/~ckern/FAANG/) ).
All data generated were held to stringent data quality standards that closely
mirrored the ENCODE consortium’s criteria [ 31
](/articles/s41467-021-22100-8#ref-CR31 "Landt, S. G. et al. ChIP-seq
guidelines and practices of the ENCODE and modENCODE consortia. Genome Res.
22, 1813–1831 \(2012\).") (Supplementary Table [ 1
](/articles/s41467-021-22100-8#MOESM1) , Supplementary Data [ 1
](/articles/s41467-021-22100-8#MOESM4) and [ 2
](/articles/s41467-021-22100-8#MOESM5) ). Hierarchical clustering based on the
Pearson correlation of read depth in bins across the genome for the five ChIP-
seq marks and the chromatin accessibility assays demonstrated data
reproducibility between two biological replicates and specificity across
tissues (Supplementary Figs. [ 2 ](/articles/s41467-021-22100-8#MOESM1) – [ 4
](/articles/s41467-021-22100-8#MOESM1) ). The reproducibility of the RNA-seq
data was similarly verified by principal component analysis (PCA) of gene
expression values both within each species (Supplementary Fig. [ 5a
](/articles/s41467-021-22100-8#MOESM1) ) and across all three species
(Supplementary Fig. [ 5b ](/articles/s41467-021-22100-8#MOESM1) ).
### Identification and annotation of REs
The data generated allowed the discovery of co-occurring histone
modifications, CTCF binding, chromatin accessibility, and gene expression,
which was used to identify regions with regulatory function and to link them
with candidate target genes. We therefore first predicted genome-wide
chromatin states in each tissue within each species using ChromHMM [ 32
](/articles/s41467-021-22100-8#ref-CR32 "Ernst, J. & Kellis, M. ChromHMM:
automating chromatin-state discovery and characterization. Nat. Methods 9,
215–216 \(2012\).") to categorize genomic regions into 14 distinct chromatin
states defined by their combination of ChIP-seq marks (Fig. [ 1b
](/articles/s41467-021-22100-8#Fig1) ). Labels assigned to each state were
determined based on previously characterized chromatin states [ 33
](/articles/s41467-021-22100-8#ref-CR33 "Hoffman, M. M. et al. Integrative
annotation of chromatin elements from ENCODE data. Nucleic Acids Res. 41,
827–841 \(2012\).") and include active promoter and transcription start site
(TSS) states, primarily defined by the presence of H3K4me3, active enhancer
states with H3K27ac and H3K4me1, polycomb repressed elements marked by
H3K27me3, and insulators bound by CTCF. 53%, 40%, and 31% of the chicken, pig,
and cattle genomes, respectively, was annotated with a ChromHMM state
corresponding to any epigenetic signal in at least one tissue, i.e., any
ChromHMM state except for “Low Signal” which indicated an absence of any of
the five ChIP-seq marks profiled. The percentage of the genome annotated with
some regulatory function varied from tissue to tissue (Fig. [ 1c
](/articles/s41467-021-22100-8#Fig1) ), reflecting the different regulatory
programs responsible for tissue-specific phenotypes, as exemplified by the
tissue-specific activity of the albumin (ALB) gene, which is highly expressed
in the liver (Supplementary Fig. [ 1b ](/articles/s41467-021-22100-8#MOESM1)
).
These predicted chromatin states were then used to identify REs in each of the
domestic animal genomes and annotate them with the tissues in which they were
active. Next, these REs were classified as TSS proximal, genic, or intergenic
based on their genomic location relative to annotated coding genes. Enrichment
for each of the histone modifications assayed indicated that TSS proximal REs
are characterized primarily by a strong H3K4me3 enrichment, consistent with
promoter activity 34 , 35 , [ 36 ](/articles/s41467-021-22100-8#ref-CR36
"Nègre, N. et al. A cis-regulatory map of the Drosophila genome. Nature 471,
527–531 \(2011\).") . A bimodal pattern of H3K4me1 enrichment in TSS proximal
REs was present, with stronger enrichment flanking the central point where the
peaks of H3K4me3, H3K27ac, and chromatin accessibility enrichment lie. This
profile matches the enrichment of ChromHMM states around annotated TSSs,
primarily with the “Active Promoter” and “Flanking TSS” states (Supplementary
Fig. [ 1a ](/articles/s41467-021-22100-8#MOESM1) ). Genic and intergenic REs
had similar profiles, with H3K27ac and H3K4me1 being the most enriched
(Supplementary Fig. [ 1c ](/articles/s41467-021-22100-8#MOESM1) ), as is
common for enhancer regions 36 , 37 , [ 38
](/articles/s41467-021-22100-8#ref-CR38 "Ernst, J. et al. Mapping and analysis
of chromatin state dynamics in nine human cell types. Nature 473, 43
\(2011\).") .
The number of REs identified in chickens was approximately half that found for
pigs and cattle (Fig. [ 1d ](/articles/s41467-021-22100-8#Fig1) ). The
difference between chicken and mammals was mostly due to a lower number of
genic and intergenic REs, while the number of TSS proximal REs was similar.
This coincides with chickens having a similar number of genes despite the
average length of gene bodies and the total size of the genome being smaller
relative to mammals [ 39 ](/articles/s41467-021-22100-8#ref-CR39 "Botero-
Castro, F., Figuet, E., Tilak, M. K., Nabholz, B. & Galtier, N. Avian Genomes
Revisited: Hidden Genes Uncovered and the Rates versus Traits Paradox in
Birds. Mol. Biol. Evol. 34, 3123–3131 \(2017\).") (Chicken: 1 GB, Pig: 2.5 GB,
Cattle: 2.7 GB). The majority of active REs (75±12% in chickens, 75 ± 12% in
pigs, and 69±15% in cattle) were in chromatin accessible regions as determined
by DNase-seq or ATAC-seq data (Fig. [ 1e ](/articles/s41467-021-22100-8#Fig1)
), supporting their active function. We also observed that genic and
intergenic REs had more tissue-specific activity as opposed to TSS proximal
REs (Supplementary Fig. [ 1d ](/articles/s41467-021-22100-8#MOESM1) ).
Furthermore, of the 11,476, 12,203, and 13,074 genes expressed in chickens,
pigs, and cattle, respectively (defined as TMM-normalized counts per million
of at least 1), 70%, 79%, and 78% contained annotated active TSS proximal REs.
These results, taken together, revealed patterns of tissue-specificity and
enrichment of histone modifications following known characteristics of
promoters and enhancers. TSS proximal REs were promoter-like, as expected,
while genic and intergenic REs exhibited characteristics of enhancers, with no
discernible difference between the two genomic locations. Therefore, these REs
are referred to as promoters, genic enhancers, and intergenic enhancers,
respectively, in the following text. We then conducted comparative epigenomic
analyses to explore the evolutionary conservation of REs across five species
including human and mouse.
### A core set of REs is conserved across divergent amniotes
Previous comparative studies from ENCODE and modENCODE have shown that while
some properties of gene regulation are highly conserved, the specific sequence
and genomic position of functional REs are not [ 40
](/articles/s41467-021-22100-8#ref-CR40 "Yue, F. et al. A comparative
encyclopedia of DNA elements in the mouse genome. Nature 515, 355–364
\(2014\).") , [ 41 ](/articles/s41467-021-22100-8#ref-CR41 "He, Q. et al. High
conservation of transcription factor binding and evidence for combinatorial
regulation across six Drosophila species. Nat. Genet. 43, 414–420 \(2011\).")
. To investigate this further with a broader selection of species, we included
human and mouse along with our three domestic animal species. The coordinates
of each regulatory element from each of the five species were mapped to the
genomes of the other species using the Ensembl v99 alignments of amniota
vertebrates. As expected, the greater the evolutionary distance between
species, the lower percentage of REs mapped (Fig. [ 2a, b
](/articles/s41467-021-22100-8#Fig2) ). Of particular note, intergenic
enhancers had a lower mapping rate compared to promoters and genic enhancers
at all evolutionary distances (Student’s _t_ -test, _p_ -value < 0.05), while
the mapping rates between promoters and genic enhancers were not significantly
different at any evolutionary distance. We then checked if the mapped
regulatory element from one species shared regulatory activity in the other
species, indicating functional conservation of the genomic location across
species. Our analysis revealed that the epigenomic landscape of mapped
promoters was conserved at an average rate of 77 ± 8% between pairs of
species, while the epigenomic landscape of enhancers, including genic and
intergenic, was only conserved at an average rate of 33 ± 8.1%, even though a
similar proportion of promoters and genic enhancers was mapped at each inter-
species comparison (Fig. [ 2b, c ](/articles/s41467-021-22100-8#Fig2) ).
Interestingly, the rate of epigenomic conservation for both promoters and
enhancers declined at a minimal degree as evolutionary distance increased,
with only one statistically significant difference in genic enhancers, between
group A (conserved in pig and cattle, 45%) and C (conserved in all mammals,
38%); and two in intergenic enhancers, between group C (32%) and D (conserved
in mammals and chicken, 25%) and groups A (38%) and D (25%). No significant
differences were observed between groups in promoters. Taken together, our
results suggested that epigenomic conservation among these five species is
independent of evolutionary distance and is not always correlated with
positional conservation among vertebrates including an avian species.
**Fig. 2: Distal regulatory elements are not positionally conserved.**
[ 
](/articles/s41467-021-22100-8/figures/2)
**a** Phylogenetic tree showing the evolutionary distance between species.
Most recent common ancestors (MRCA) are labeled and referenced in Fig. [ 3b
](/articles/s41467-021-22100-8#Fig3) and [ c
](/articles/s41467-021-22100-8#Fig3) . **b** Percentage of regulatory elements
whose genomic coordinates could be mapped to other species, grouped by
evolutionary distance. Each pair of species produces two data points, e.g.
Cattle REs mapped to pig and pig REs mapped to cattle. **c** Percentage of
mapped regulatory elements that were conserved, i.e. overlapped with a
regulatory element identified in the target species. Asterisks indicate _p_
-values <0.05 of a one-tailed Student’s _t_ -test (genic A–C _p_ -value =
0.03304, intergenic A–D _p_ -value = 0.01402, intergenic C and D _p_ -value =
0.01238). No _p_ -values were <0.01. **d** KEGG pathways enriched in genes
with promoters conserved across all species. Benjamini–Hochberg adjusted _p_
-values were obtained using DAVID ( _n_ = 3380 genes).
[ Full size image ](/articles/s41467-021-22100-8/figures/2)
By examining epigenomic conservation within lineages, rather than just
pairwise between species (Supplementary Fig. [ 6
](/articles/s41467-021-22100-8#MOESM1) ), we found a set of 9458 REs conserved
across the mammals included in this study, representing similar number of
promoters and enhancers. Including chicken, 3153 promoters and 1452 enhancers
were conserved across all five species. This result revealed a considerable
regulatory conservation across over 300 million years of evolution. For
enhancers conserved across all five species, a very small number were tissue-
specific, despite most enhancers being tissue-specific, suggesting these
conserved enhancers are involved in basic cellular functions universal to all
cell types. Further KEGG [ 42 ](/articles/s41467-021-22100-8#ref-CR42
"Kanehisa, M. & Goto, S. KEGG: kyoto encyclopedia of genes and genomes.
Nucleic Acids Res. 28, 27–30 \(2000\).") pathway enrichment of genes with
conserved promoters supports this notion, with the most enriched pathways
related to core metabolic processes (Fig. [ 2d
](/articles/s41467-021-22100-8#Fig2) ). While the sequence and position of
enhancers showed low conservation, we next explored whether higher
conservation exists with other features of REs such as transcription factor
binding and the targeted genes they regulate.
### Tissue-specific transcription factor enrichment in active REs is highly
conserved across vertebrates
Transcription factors that bind to accessible chromatin within REs have been
shown to have distinct tissue-specific activity that is conserved between
mouse and human [ 25 ](/articles/s41467-021-22100-8#ref-CR25 "Stergachis, A.
B. et al. Conservation of trans-acting circuitry during mammalian regulatory
evolution. Nature 515, 365–370 \(2014\).") . Using the chromatin accessibility
data generated in this study, we performed transcription factor footprinting
[ 43 ](/articles/s41467-021-22100-8#ref-CR43 "Neph, S. et al. An expansive
human regulatory lexicon encoded in transcription factor footprints. Nature
489, 83–90 \(2012\).") to identify potential transcription factor (TF) binding
events within characterized REs. Using these footprints, we identified 26
transcription factor motifs from the HOMER [ 44
](/articles/s41467-021-22100-8#ref-CR44 "Heinz, S. et al. Simple combinations
of lineage-determining transcription factors prime cis-regulatory elements
required for macrophage and B cell identities. Mol. Cell 38, 576–589
\(2010\).") vertebrate transcription factor database that were enriched in
tissue-specific TF footprints in at least one tissue in each domestic animal
species (Fig. [ 3 ](/articles/s41467-021-22100-8#Fig3) ), with the three brain
tissues combined for this analysis. These transcription factor motifs showed
similar patterns of enrichment across species, including human and mouse,
implying a tissue-specific conserved regulatory function. FOXA2 and HNF1B, for
example, were enriched and highly expressed in liver in all three domestic
animal species as well as mouse, and are known to be important for liver
development [ 45 ](/articles/s41467-021-22100-8#ref-CR45 "Smith, R. P. et al.
Massively parallel decoding of mammalian regulatory sequences supports a
flexible organizational model. Nat. Genet. 45, 1021–1028 \(2013\).") . The
SIX1 transcription factor plays a role in adult skeletal muscle development [
46 ](/articles/s41467-021-22100-8#ref-CR46 "Wu, W. et al. The role of Six1 in
the genesis of muscle cell and skeletal muscle development. Int. J. Biol. Sci.
10, 983–989 \(2014\).") and was expressed in muscle in all three domestic
animal species with motif enrichment in muscle-specific TF footprints.
**Fig. 3: Transcription factor motifs enriched in tissue-specific footprints
show similar patterns across species.**
[ 
](/articles/s41467-021-22100-8/figures/3)
Transcription factor motifs enriched in at least one tissue in all three
domestic animal species. The size of the circle indicates the statistical
significance of motif enrichment (Benjamini–Hochberg adjusted _p_ -values
using HOMER), while the color indicates the expression of the corresponding
transcription factor gene, normalized to the maximum expression across tissues
within each species.
[ Full size image ](/articles/s41467-021-22100-8/figures/3)
### Target gene prediction of enhancers identified potential regulators
conserved across species
To predict RE target genes, we correlated gene expression across samples with
the level of enrichment of histone modifications or open chromatin at
enhancers. The analysis was performed on all three RE groups, as some
promoters have been found to interact with other promoters in an enhancer-like
manner [ 47 ](/articles/s41467-021-22100-8#ref-CR47 "Dixon, J. R. et al.
Topological domains in mammalian genomes identified by analysis of chromatin
interactions. Nature 485, 376–380 \(2012\).") . Because this method relies on
Spearman rank correlation between values across tissues, genes with small
variances in expression (variance <6 CPM) were excluded from the analysis to
limit false positive associations due to random chance. Similarly, REs with
small variances in the enrichment of histone modifications or open chromatin
were also removed as potential regulators. As it is widely recognized that
enhancer–promoter interactions occur most predominantly within TADs [ 48
](/articles/s41467-021-22100-8#ref-CR48 "Rao, S. S. et al. A 3D map of the
human genome at kilobase resolution reveals principles of chromatin looping.
Cell 159, 1665–1680 \(2014\).") , but not necessarily with the RE nearest to
the gene 49 , 50 , [ 51 ](/articles/s41467-021-22100-8#ref-CR51 "Lettice,
L. A. et al. A long-range Shh enhancer regulates expression in the developing
limb and fin and is associated with preaxial polydactyly. Hum. Mol. Genet. 12,
1725–1735 \(2003\).") , we predicted TADs for chickens, pigs, and cattle using
CTCF-binding sites, given that Hi-C data is not available for the samples
under study. Predicted TADs covered 82%, 91%, and 92% of the genomes of
chicken, pig, and cattle, respectively, which is in the range of previous Hi-C
data generated from mouse cell lines which identified 2200 TADs that covered
91% of the genome [ 47 ](/articles/s41467-021-22100-8#ref-CR47 "Dixon, J. R.
et al. Topological domains in mammalian genomes identified by analysis of
chromatin interactions. Nature 485, 376–380 \(2012\).") .
As a preliminary step, we measured the Spearman correlation of gene expression
and ChIP-seq or chromatin accessibility signal within enhancers that
overlapped or were nearest to the gene. As previously stated, REs do not
always regulate their nearest gene; however, the situation is frequent enough
to provide a proof-of-concept for the central assumption of our target gene
prediction method—that gene expression and epigenetic signals are
correlated—and to establish a baseline correlation level of these “naïve”
enhancer–gene pairs. Results of this analysis indicated that H3K27ac was the
most consistently correlated with gene expression at both genic and intergenic
enhancers across all three species (Fig. [ 4c, d
](/articles/s41467-021-22100-8#Fig4) ). Additionally, H3K27ac has been
previously shown to be predictive of gene expression [ 52
](/articles/s41467-021-22100-8#ref-CR52 "Karlić, R., Chung, H.-R., Lasserre,
J., Vlahoviček, K. & Vingron, M. Histone modification levels are predictive
for gene expression. Proc. Natl Acad. Sci. USA 107, 2926 \(2010\).") , [ 53
](/articles/s41467-021-22100-8#ref-CR53 "Zhang, Z. & Zhang, M. Q. Histone
modification profiles are predictive for tissue/cell-type specific expression
of both protein-coding and microRNA genes. BMC Bioinforma. 12, 155 \(2011\).")
. Therefore, we used H3K27ac as the signal of regulatory element activity for
target gene prediction.
**Fig. 4: Target gene prediction of regulatory elements.**
[ 
](/articles/s41467-021-22100-8/figures/4)
**a** Topologically associated domains (TADs) predicted by CTCF ChIP-seq data.
**b** The number of predicted RE–gene pairs, the total number of REs and genes
in at least one pair, and the mean and median number of predicted genes per RE
and REs per gene. **c** Spearman rank correlation of normalized read depth in
each genic RE with the expression of the gene it overlaps (blue bars) and the
expression of the genes predicted as targets (orange bars). **d** Spearman
rank correlation of normalized read depth in each intergenic RE with the
expression of the nearest gene (blue bars) and the expression of the genes
predicted as targets (orange bars). **e** Principal component plot of the
normalized read depth of H3K27ac of intergenic REs predicted to target genes
with one-to-one orthologs across all three species.
[ Full size image ](/articles/s41467-021-22100-8/figures/4)
We predicted 29,526 RE-gene interactions in chickens (involving 10,937 REs and
5519 genes), 58,523 in pigs (31,735 REs and 8233 genes), and 28,849 in cattle
(16,348 REs and 7113 genes, Fig. [ 4b ](/articles/s41467-021-22100-8#Fig4) ).
Most genic REs were not predicted to target the gene they overlap, with 22.1%
in chickens, 35.2% in pig, and 40.4% in cattle predicted to target their
overlapping gene. Because REs may have multiple predicted target genes, some
genic REs that were predicted to target the gene they overlap were also
predicted to target other genes, which would have not been captured with the
naïve approach. In total, 92.6% of genic REs in chickens, 82.3% in pigs, and
74.6% in cattle were predicted to target a gene they do not overlap. Similarly
with intergenic REs, only 14.9% in chickens, 20.7% in pigs, and 22.6% in
cattle were predicted to target their nearest gene and 95.7% in chickens,
89.9% in pigs, and 87.1% in cattle were predicted to target a gene that it was
not nearest to. REs in chickens were predicted to interact with more genes per
RE on average compared to pigs and cattle. We verified that this was not
caused by a small number of outliers with high numbers of target genes by re-
calculating the average using only REs with 10 or fewer target genes. These
new averages were 2.5 in chickens, 1.8 in pigs, and 1.7 in cattle. In fact,
the RE with the highest number of predicted target genes was a pig RE with 33
predicted targets, while the maximum in chickens and cattle is 23 and 22,
respectively.This result suggests that chicken REs are more versatile than
those of mammals. In fact, the number of RE–gene interactions predicted in
chickens and cattle were very similar, despite chickens having about half the
total number of REs. Compared to the previous correlations based on the
nearest or overlapping gene, the Spearman correlation of gene expression with
epigenetic signals of the predicted RE–gene pairs became more positively
correlated with all marks, except for the repressive H3K27me3 mark, which
became more negatively correlated, despite only H3K27ac being used in the
prediction (Fig. [ 4d ](/articles/s41467-021-22100-8#Fig4) ). This indicates
that our predictions are more accurate than the naïve method of assigning
enhancers to their closest gene.
To gain insight into the regulatory pathways predicted by these correlative
analyses above, we first clustered REs based on their H3K27ac signal across
tissues, which resulted in tissue-specific RE clusters. Next, we performed
gene ontology analysis of the genes targeted by the REs in each group. These
analyses revealed that REs with tissue-specific activity targeted genes with
tissue-specific functions (Supplementary Fig. [ 7
](/articles/s41467-021-22100-8#MOESM1) ). For most clusters, the enriched GO
terms show tissue-specific biological processes matching the tissues with the
highest H3K27ac signal in the REs belonging to the cluster. TF motifs enriched
in REs that were predicted to target genes with tissue-specific expression
found numerous TFs in common across the three domestic animal species
(Supplementary Fig. [ 8 ](/articles/s41467-021-22100-8#MOESM1) ). ETS1 and
FLI1, for example, were both expressed in spleen and their binding motifs
enriched in REs predicted to target spleen-specific genes, suggesting a
conserved tissue-specific role for these TFs.
To more directly measure the similarity of gene regulation across species, PCA
on the H3K27ac enrichment values at REs predicted to target orthologous genes
in each domestic animal species resulted in stronger clustering by tissue than
by species in all three RE groups (Fig. [ 4e
](/articles/s41467-021-22100-8#Fig4) ; Supplementary Fig. [ 9a, b
](/articles/s41467-021-22100-8#MOESM1) ). Taken together, these results show
that while REs are not highly conserved in their genomic positions, there is
tissue-specific conservation of regulatory features across species.
### An annotated data resource for comparative and complex trait analysis
The data generated in this study represents an important resource for
comparative analysis as it provides a set of epigenomic assays from the same
tissues at the same developmental stage across three species with consistency
in the protocols used for sample collection and data generation. As we have
shown, these data show high concordance with previously reported data from the
human and mouse ENCODE projects, correlate well with gene expression and
chromatin accessibility, and show distinct tissue-specific patterns that
relate to biologically relevant functions. Therefore, this data can be
regarded as a reliable epigenetic resource for these species. This dataset
will facilitate further comparative epigenomic analyses, which was previously
limited due to sparse epigenomic data available from species other than model
organisms, as more epigenomic data is generated by the FAANG Consortium and
for species outside the scope of FAANG. For researchers interested in one of
the agricultural species represented by these data, the provided resources can
be utilized to refine potential causative variants identified from genome-wide
association studies (GWAS) for further functional validation.
As an example, 17,201,383 sequence variants associated with various complex
traits in dairy cattle via expression QTL scan [ 54
](/articles/s41467-021-22100-8#ref-CR54 "Xiang, R. et al. Genome variants
associated with RNA splicing variations in bovine are extensively shared
between tissues. BMC Genom. 19, 521 \(2018\).") , variant function prediction
[ 55 ](/articles/s41467-021-22100-8#ref-CR55 "Xiang, R. et al. Quantifying the
contribution of sequence variants with regulatory and evolutionary
significance to 34 bovine complex traits. Proc. Natl Acad. Sci. USA 116, 19398
\(2019\).") , and GWAS were overlapped with the cattle REs identified in this
study. The distribution of _p_ -values showed a clear skew towards SNPs inside
REs having a higher density at lower _p_ -values while SNPs outside REs had
higher density at higher _p_ -values in traits such as milk protein content,
milk fat content, and total milk volume (Fig. [ 5a–c
](/articles/s41467-021-22100-8#Fig5) ). Categorizing sequence variants by
types such as gene expression QTL (geQTL) or metabolite QTL (mQTL) showed that
a higher percentage of these SNPs were found in REs compared to variants not
in these categories (Fig. [ 5d ](/articles/s41467-021-22100-8#Fig5) ). The
category with the highest percentage in REs, geQTLs, appeared about 2.5 times
more frequently (Fisher exact _p_ -value < 0.00001) in REs compared to
uncategorized SNPs, supporting the role these REs play in gene regulation. In
summary, this analysis further illustrated that REs annotated in the current
study can significantly narrow down the search for causative variants
responsible for complex traits and fill an important gap in biology by
predicting phenotype by genotype.
**Fig. 5: Overlap with dairy cattle GWAS SNPs.**
[ 
](/articles/s41467-021-22100-8/figures/5)
**a** – **c** The distribution of _p_ -values from GWAS for milk protein
content ( **a** ), milk fat content ( **b** ), and milk volume ( **c** ), for
SNPs inside and outside of characterized REs in cattle. The _p_ -values were
calculated by previous studies from which the SNPs were obtained (citations in
text). **d** The percentage of SNPs in REs categorized as geQTL (gene
expression QTL), ChIPSeq (SNPs in ChIP-seq peaks from previously generated
H3K4me3 and H3K27ac data from liver, muscle, and mammary gland), aseQTL
(allele-specific expression QTL), mQTL (metabolites QTL), sQTL (splicing QTL),
eeQTL (exon expression QTL), selection.sig (selection signature between dairy
and beef cattle), cons100way (variants under genomic sites conserved across
100 vertebrate species), young (variants that are recently selected), and
other SNPs not placed in any of the previous categories. SNPs may belong to
multiple categories.
[ Full size image ](/articles/s41467-021-22100-8/figures/5)
## Discussion
We report a large-scale analysis comparing the epigenomes, genomes, and
transcriptomes of biologically diverse tissues in multiple vertebrates,
including birds, and provide a comparative view of the evolutionary properties
of the avian and mammalian epigenome. In general, intergenic enhancers had low
genomic positional conservation compared to promoters and genic enhancers.
Moreover, RE conservation across mammals and birds was independent of
evolutionary distance, suggesting a core set of evolutionarily stable REs
among vertebrates. Further analysis demonstrated that REs (enhancers and
promoters) conserved between mammalian and avian species play essential roles
in modulating genes and signaling pathways related to basic metabolic
functions.
Furthermore, tissue-specific conservation of TF enrichment and target genes of
RE across the vertebrate species (despite the generally low genomic level of
conservation) highlight an importantfunctional role of REs in modulating
biological processes. Of particular note, the number of genes regulated by
each enhancer in the chicken genome were much greater than in the cattle and
pig genomes. We speculate that enhancers in chickens are more multi-functional
compared to their mammalian counterparts.
Finally, we demonstrated how this data can be utilized to inform studies
seeking to link phenotype to genotype, such as by reducing the number of SNPs
identified from a GWAS to those more likely to be causative variants. The
epigenetic data and functional annotation of REs generated provide a resource
for future research in animal agriculture and comparative epigenomic research.
As ongoing and future FAANG projects continue, expanding the datasets to more
tissues and developmental stages, as well as generating data from female
individuals and exploring newer technologies such as single-cell-sequencing
assays, the resource presented in this manuscript will be an important
baseline upon which to compare these new datasets.
## Methods
### Genetic resources
Animals were euthanized and tissue samples were collected with all necessary
permissions granted, following Protocol for Animal Care and Use #18464,
approved by the Institutional Animal Care and Use Committee (IACUC),
University of California (UC), Davis. The chickens used in this study were
male F 1 crosses of the highly inbred Line 6 and Line 7 from the USDA, ARS,
Avian Disease and Oncology Laboratory (ADOL) and were euthanized with CO 2
under USDA inspection at 20 weeks old. Two castrated male Yorkshire littermate
pigs were humanely slaughtered using electrocution in accordance with common
practices in slaughterhouses at 6 months old under USDA inspection at Michigan
State University. Cattle were slaughtered at UC, Davis using captive bolt
under USDA inspection at 14 months old, and were intact male Line 1 Herefords
that had the same sire, provided by Fort Keogh Livestock and Range Research
Lab [ 56 ](/articles/s41467-021-22100-8#ref-CR56 "Kern, C. et al. Genome-wide
identification of tissue-specific long non-coding RNA in three farm animal
species. BMC Genom. 19, 684 \(2018\).") . All animals were in a sexually
mature adult stage when euthanized. Tissue samples were flash frozen in liquid
nitrogen then stored at –80 °C until further assay processing. The tissues
analyzed were chosen based on their relevance to important complex traits as
well as to represent a wide range of biological functions. Two biological
replicates were used per species, for a total of 16 tissue samples per
species.
### Library preparation and sequencing
The RNA-seq datasets used in this manuscript has been previously published [
56 ](/articles/s41467-021-22100-8#ref-CR56 "Kern, C. et al. Genome-wide
identification of tissue-specific long non-coding RNA in three farm animal
species. BMC Genom. 19, 684 \(2018\).") . The ATAC-seq datasets were generated
using a previously published protocol [ 57
](/articles/s41467-021-22100-8#ref-CR57 "Halstead, M. M. et al. Systematic
alteration of ATAC-seq for profiling open chromatin in cryopreserved nuclei
preparations from livestock tissues. Sci. Rep. 10, 5230–5230 \(2020\).") , and
is described below.
For isolation and cryopreservation of nuclei, used for DNase-seq and ATAC-seq
assays, fresh tissue was minced with razor blade and transferred to gentleMACs
C tube containing 10 ml of sucrose buffer, then homogenized using the
gentleMACS Dissociator. Homogenate was filtered through a 100 μM Steriflip
vacuum filter and DMSO added to a final 10% concentration, then pipette mixed
several times and aliquoted into 2 ml cryovials. Samples were stored overnight
in −80 °C in freezing container with isopropanol and then moved into storage
boxes for long-term storage.
ChIP-seq experiments were performed on frozen tissue using the iDeal ChIP-seq
kit for Histones (Diagenode Cat.#C01010059, Denville, NJ) according to the
manufacturer’s protocol except for the following changes. 20–30 mg of frozen
tissue was powdered using liquid nitrogen in pre-chilled mortar. Cross-linking
was performed with 1% formaldehyde which was diluted from 16% methanol-free
formaldehyde (Thermo Scientific, Cat.#28906, Waltham, MA) for 8 min and
quenched with glycine for 10 min. Nuclei were harvested by centrifugation at
2000× _g_ for 5 min and resuspended in iS1 buffer for incubation on ice for 30
min. Chromatin was sheared using the Covaris E220 between 6 and 12 min
depending on the tissue. For immunoprecipitation experiments, about 1000 ng of
sheared chromatin (estimated from DNA extraction) was used as input after
which the kit protocol was followed with 1 μg (histone modifications) or 1.5
μg (CTCF) of antibody. The following antibodies used were from Diagenode:
H3K4me3 (in kit), H3K27me3 (#C15410069), H3K27ac (#C15410174), H3K4me1
(#C15410037), and CTCF (#15410210). An input (no antibody) was performed for
each sample. NEBNext Ultra DNA library prep kit for Illumina libraries (New
England Biolabs #E7645L, Ipswich, MA) was used for library construction,
selecting for 150–200 bp (H3K4me3, H3K27ac, CTCF) or 200–400 bp (H3K27me3,
H3K4me1) insert fragment sizes using Ampure beads (Beckman Coulter #A63881).
Libraries were sequenced on Illumina’s HiSeq 4000 with single-end 50 bp reads.
A detailed protocol used to prepare the ChIP-seq libraries can be found at
ftp://ftp.faang.ebi.ac.uk/ftp/protocols/assays/UCD_SOP_ChIP-
Seq_Animal_tissue_20161101.pdf.
DNase-seq datasets were generated by the Stamatoyannopoulos’ Lab at University
of Washington using a previously published protocol [ 58
](/articles/s41467-021-22100-8#ref-CR58 "John, S. et al. Chromatin
accessibility pre-determines glucocorticoid receptor binding patterns. Nat.
Genet. 43, 264–268 \(2011\).") . Briefly, cryopreserved nuclei were slowly
defrosted on ice, pelleted at 500 × _g_ , and resuspended in 37 °C DNase I
digestion buffer (13.5 mM Tris–HCl pH 8.0, 87 mM NaCl, 54 mM KCl, 6 mM CaCl 2
, 0.9 mM EDTA, 0.45 mM EGTA, 0.45 mM spermidine). After a 3 min incubation,
the reaction was stopped with 2× stop buffer (50 mM Tris–HCl pH 8.0, 100 mM
NaCl, 0.1% SDS, 100 mM EDTA pH 8.0, 1 mM spermidine, 0.3 mM spermine). Samples
were treated with RNase for 1 h at 37 °C, then an additional hour at 55 °C
with proteinase K. DNA fragments were isolated, libraries prepared, and
sequenced on Illumina’s Hiseq 2500 with 50 bp paired-end sequencing.
For ATAC-seq, cryopreserved nuclei prepared from fresh tissue (as described
above) were slowly thawed on ice, centrifuged for 5 min at 500 rcf, and
resuspended in cold PBS. Nuclei were then washed once with cold ATAC-seq cell
lysis buffer and resuspended with cold PBS for counting on a hemocytometer.
Approximately 200K cryopreserved nuclei were centrifuged, supernatant
aspirated, then treated with 50 μl transposition mix (25 μl TD buffer, 2.5 μl
TDE1, 22.5 μl ddH 2 O) for 1 h at 37 °C and 500 rcf. DNA was purified using
the MinElute PCR purification kit (Qiagen, #28004, Germantown, MD) and diluted
with 10 μl EB buffer. DNA was amplified with primers whose detailed
descriptions are found in Buenrostro et al. (2013) [ 30
](/articles/s41467-021-22100-8#ref-CR30 "Buenrostro, J. D., Giresi, P. G.,
Zaba, L. C., Chang, H. Y. & Greenleaf, W. J. Transposition of native chromatin
for fast and sensitive epigenomic profiling of open chromatin, DNA-binding
proteins and nucleosome position. Nat. Methods 10, 1213–1218 \(2013\).") .
Libraries were purified using the MinElute PCR purification kit and run on
Agilent Bioanalyzer (Agilent, Santa Clara, CA) for quality traces. Size-
selection on libraries for 150–250 bp fragments was performed on PippinHT
system (Sage Science, Beverly, MA). Libraries were sequenced on Illumina’s
NextSeq with PE 40bp reads.
### Genomes and annotations
Across all analyses, the GalGal6 genome and Ensembl version 99 annotation was
used for chickens, the Sscrofa11.1 genome and Ensembl version 99 annotation
for pigs, and ARS-UCD1.2 genome and Ensembl version 99 annotation used for
cattle.
### Processing of high-throughput sequencing data
RNA-seq reads were trimmed with Trim Galore! 0.4.5 ( [
https://www.bioinformatics.babraham.ac.uk/projects/trim_galore/
](https://www.bioinformatics.babraham.ac.uk/projects/trim_galore/) ) using
default parameters, then aligned with STAR [ 59
](/articles/s41467-021-22100-8#ref-CR59 "Dobin, A. et al. STAR: ultrafast
universal RNA-seq aligner. Bioinformatics 29, 15–21 \(2012\).") 2.5.4a
(--outFilterMultimapNmax 20 --alignSJoverhangMin 8 --alignSJDBoverhangMin 1
--outFilterMismatchNmax 999 --alignIntronMin 20) to the respective genome.
Alignments with an alignment MAPQ score <30 were filtered using SAMtools [ 60
](/articles/s41467-021-22100-8#ref-CR60 "Li, H. et al. The Sequence
Alignment/Map format and SAMtools. Bioinformatics 25, 2078–2079 \(2009\).")
1.10. Gene counts were determined using htseq-count [ 61
](/articles/s41467-021-22100-8#ref-CR61 "Anders, S., Pyl, P. T. & Huber, W.
HTSeq—a Python framework to work with high-throughput sequencing data.
Bioinformatics 31, 166–169 \(2014\).") 0.11.1, and then TMM normalization was
performed with EdgeR [ 62 ](/articles/s41467-021-22100-8#ref-CR62 "Robinson,
M. D., McCarthy, D. J. & Smyth, G. K. edgeR: a Bioconductor package for
differential expression analysis of digital gene expression data.
Bioinformatics 26, 139–140 \(2009\).") . Genes with a TMM-normalized counts
per million (CPM) equal to or above 1 were considered expressed. Genes were
considered to have tissue-specific expression if they were expressed at least
4-fold higher than all other tissues.
For broad marks (DNase-seq, ATAC-seq, and H3K27me3), a depth of 40 million
aligned and filtered reads was targeted, while for the narrow marks, the
target was 20 million. ChIP-seq reads were trimmed with Trim Galore! 0.4.5
using default parameters, then aligned using BWA [ 63
](/articles/s41467-021-22100-8#ref-CR63 "Li, H. Aligning sequence reads, clone
sequences and assembly contigs with BWA-MEM. arXiv: 1303.3997 \(2013\).")
0.7.17 with the “mem” alignment mode and default parameters. Alignments with a
MAPQ score <30 were filtered using SAMtools 1.10, and then duplicates were
marked and removed using the Picard toolkit [ 64
](/articles/s41467-021-22100-8#ref-CR64 "Broad Institute. Picard Toolkit.
http://broadinstitute.github.io/picard/
\(2019\).") 2.18.17. Various quality metrics were calculated and are summarized in Supplementary Table [ 1 ](/articles/s41467-021-22100-8#MOESM1) , with detailed per-library statistics in Supplementary Files [ 1 ](/articles/s41467-021-22100-8#MOESM1) and [ 2 ](/articles/s41467-021-22100-8#MOESM1) . The non-redundant fraction (NRF) is the ratio of reads after de-duplication to reads before. PCR bottleneck coefficient 1 (PBC1) is the ratio of genomic locations with exactly 1 mapped read to the total number of genomic locations with mapped reads. PBC2 is similar to PBC1, however, the denominator of the ratio is the number of genomic locations with 2 mapped reads. By ENCODE standards, an NRF in the range of 0.5–0.8 is “acceptable”, a PBC1 in the same range indicates “moderate bottlenecking”, and a PBC2 between 3 and 10 is labeled “mild bottlenecking”. The normalized strand coefficient (NSC) and relative strand coefficient (RSC) were calculated using SPP [ 65 ](/articles/s41467-021-22100-8#ref-CR65 "Kharchenko, P. V., Tolstorukov, M. Y. & Park, P. J. Design and analysis of ChIP-seq experiments for DNA-binding proteins. Nat. Biotechnol. 26, 1351–1359 \(2008\).") to estimate enrichment of the ChIP signal, where an NSC >1.1 and an RSC >1 indicate acceptable enrichment. The Jensen–Shannon distance (JSD) was calculated between the ChIP and input libraries using DeepTools [ 66 ](/articles/s41467-021-22100-8#ref-CR66 "Ramírez, F., Dündar, F., Diehl, S., Grüning, B. A. & Manke, T. deepTools: a flexible platform for exploring deep-sequencing data. Nucleic Acids Res. 42, W187–W191 \(2014\).") 3.3.0, providing a measure of enrichment that includes the input data, which NSC and RSC do not. The inclusion of the input read alignments in the JSD metric made it a more robust metric in discerning good data from bad by showing greater correlation with the number of peaks called and the fraction of reads in peaks (FRiP), as well as visual inspection of the data on a genome browser. FRiP measures the percentage of reads aligned to peak regions called by MACS2 [ 67 ](/articles/s41467-021-22100-8#ref-CR67 "Zhang, Y. et al. Model-based analysis of ChIP-Seq \(MACS\). Genome Biol. 9, R137 \(2008\).") 2.1.1 and was determined using DeepTools 3.3.0. Peaks were called with a _q_ -value cutoff of 0.01 for H3K4me3, H3K27ac, H3K4me1, and CTCF. H3K27me3, ATAC-seq, and DNase-seq peaks were called in broad mark mode with a _q_ -value cutoff of 0.05. To determine regions of chromatin accessibility, peaks were called with the same parameters used to determine FRiP, but with DNase-seq and ATAC-seq using the combined alignments from both replicates.
The clustering of ChIP-seq and chromatin accessibility data was done using
DeepTools 3.3.0 to get a normalized read count in 1000 bp bins across the
genome, then doing hierarchical clustering with Pearson correlation as the
distance metric. ChIP-seq reads were not normalized by the input reads for
this clustering, and reads were extended to 200 bp. The reproducibility of the
RNA-seq data was similarly verified by PCA of gene expression values within
each species (Supplementary Fig. [ 5a ](/articles/s41467-021-22100-8#MOESM1) )
and of the expression values of 11,317 one-to-one orthologs across all three
species (Supplementary Fig. [ 5b ](/articles/s41467-021-22100-8#MOESM1) ).
Principal component (PC) 1 separated chicken from the cattle and pig, with
cattle and pig samples clustering more closely by tissue than by species. A
plot of PC2 and PC3 showed clustering by tissue across all species
(Supplementary Fig. [ 5b ](/articles/s41467-021-22100-8#MOESM1) ).
### Annotation of active regulatory regions
ChromHMM [ 32 ](/articles/s41467-021-22100-8#ref-CR32 "Ernst, J. & Kellis, M.
ChromHMM: automating chromatin-state discovery and characterization. Nat.
Methods 9, 215–216 \(2012\).") 1.19 was used to train a chromatin state
prediction model incorporating all ChIP-seq data from all marks, tissues, and
species. Because DNase-seq data was generated for chickens while ATAC-seq data
was generated for cattle and pigs, these data sets were not used in the
chromatin state model. Multiple models were trained with varying numbers of
states and the final 14-state model was selected to have the maximum number of
states with distinct ChIP-seq mark combinations. No other parameters were
changed from their defaults. We used chromatin state labels that resembled
those used for the chromatin state models created by the ENCODE projects [ 4
](/articles/s41467-021-22100-8#ref-CR4 "Consortium, E. P. The ENCODE
\(ENCyclopedia Of DNA Elements\) Project. Science 306, 636–640 \(2004\).") , [
5 ](/articles/s41467-021-22100-8#ref-CR5 "Stamatoyannopoulos, J. A. et al. An
encyclopedia of mouse DNA elements \(Mouse ENCODE\). Genome Biol. 13, 1–5
\(2012\).") and assigned them to states based on their combination of histone
modifications and enrichment around the TSS (Fig. [ 1a
](/articles/s41467-021-22100-8#Fig1) ), as well as their enrichment at various
genomic elements, conserved elements, and open chromatin regions (Fig. [ 1b
](/articles/s41467-021-22100-8#Fig1) ).
To consolidate and annotate the REs in each of the domestic animal genomes, we
first identified all active regions for each tissue by merging consecutive
regions predicted as chromatin states associated with activity (states 1–6, 8,
9, and 11) and then combined them across tissues using BEDTools [ 68
](/articles/s41467-021-22100-8#ref-CR68 "Quinlan, A. R. & Hall, I. M.
BEDTools: a flexible suite of utilities for comparing genomic features.
Bioinformatics 26, 841–842 \(2010\).") 2.27.1. This step helped to avoid
technical issues when comparing chromatin states across tissues, such as a
broader H3K27ac peak than H3K4me3 at a TSS resulting in small regions of
enhancer-associated states within promoters. The REs from individual tissues
that were merged to form each combined RE were used to determine its tissue
activity. REs active in only a single tissue were considered tissue-specific.
The active REs were then classified into groups based on their genomic
location relative to annotated coding genes in the genome. Regions within 2 kb
of the TSS of an annotated protein-coding transcript were classified as “TSS
Proximal REs”. Regions overlapping a gene body, but not within 2 kb of a TSS,
were classified as “genic REs,” and the remaining regions were classified as
“intergenic REs”. Regions that were within 2 kb of a non-coding transcript TSS
or an unannotated TSS detected from RNA-seq data (from a previous analysis of
the data [ 56 ](/articles/s41467-021-22100-8#ref-CR56 "Kern, C. et al.
Genome-wide identification of tissue-specific long non-coding RNA in three
farm animal species. BMC Genom. 19, 684 \(2018\).") ) were excluded from these
groups.
The enrichment of the four histone modifications and chromatin accessibility
within each RE group was done with DeepTools 3.3.0 computeMatrix with
parameters “reference-point –referencePoint center -a 3000 -b 3000”.
### Conservation of REs
Human and mouse ENCODE data for the same tissues and developmental stages were
downloaded from the ENCODE Consortium and were used to perform chromatin state
annotation and identify REs using the same pipeline used to process the
chicken, cattle, and pig data. The GRCh38 and GRCm38 genome assemblies were
used with Ensembl Annotation version 99 for both. Coordinates were mapped
between genomes using Ensembl Compara’s amniota vertebrate multiple sequence
alignment. The evolutionary distances shown in Fig. [ 2a
](/articles/s41467-021-22100-8#Fig2) were obtained from TimeTree [ 69
](/articles/s41467-021-22100-8#ref-CR69 "Kumar, S., Stecher, G., Suleski, M. &
Hedges, S. B. TimeTree: a resource for timelines, timetrees, and divergence
times. Mol. Biol. Evol. 34, 1812–1819 \(2017\).") . A regulatory element was
considered conserved if its mapped coordinates overlapped with a regulatory
element in another species by at least 1 bp. DAVID [ 70
](/articles/s41467-021-22100-8#ref-CR70 "Huang, D. W., Sherman, B. T. &
Lempicki, R. A. Systematic and integrative analysis of large gene lists using
DAVID bioinformatics resources. Nat. Protoc. 4, 44 \(2008\).") 6.8 was used to
determine enriched KEGG [ 42 ](/articles/s41467-021-22100-8#ref-CR42
"Kanehisa, M. & Goto, S. KEGG: kyoto encyclopedia of genes and genomes.
Nucleic Acids Res. 28, 27–30 \(2000\).") pathways.
### Transcription factor footprinting
To identify transcription factor footprints, the HINT tool from the Regulatory
Genomics Toolbox 0.12.3 was used with –atac-seq for ATAC-seq data and –dnase-
seq –bias-correction for DNase-seq data, which can identify footprints from
both DNase-seq [ 71 ](/articles/s41467-021-22100-8#ref-CR71 "Gusmao, E. G.,
Allhoff, M., Zenke, M. & Costa, I. G. Analysis of computational footprinting
methods for DNase sequencing experiments. Nat. methods 13, 303–309 \(2016\).")
and ATAC-seq [ 72 ](/articles/s41467-021-22100-8#ref-CR72 "Li, Z. et al.
Identification of transcription factor binding sites using ATAC-seq. Genome
Biol. 20, 45 \(2019\).") data. DNase-seq data in chickens generated 338,547
distinct footprints across all tissues, including 32,929 containing the CTCF-
binding motif. Furthermore, ChIP-seq for CTCF validated 93% of these
footprints. On the other hand, ATAC-seq data in pigs and cattle generated
4,976,047 and 4,345,973 in pigs and cattle, respectively, with 45% of 89,245
CTCF footprints in pigs and 43% of 70,171 CTCF footprints in cattle validated
by CTCF ChIP-seq. The difference in the number of footprints identified in
mammals compared to chickens, as well as the difference in the agreement of
CTCF occupied footprints with ChIP-seq, was due to a disparity in the two open
chromatin assays used, rather than a biological difference between mammals and
avian, as confirmed by ATAC-seq performed on the same chicken lung tissue that
was used to generate the DNase-seq data for chicken lung [ 57
](/articles/s41467-021-22100-8#ref-CR57 "Halstead, M. M. et al. Systematic
alteration of ATAC-seq for profiling open chromatin in cryopreserved nuclei
preparations from livestock tissues. Sci. Rep. 10, 5230–5230 \(2020\).")
(94,376 DNase-seq footprints, 92% of 5888 CTCF footprints validated by a CTCF
ChIP-seq peak; 797,042 ATAC-seq footprints, 52% of 5307 CTCF footprints with a
ChIP-seq peak).
Enrichment of transcription factor motifs in footprints was done by adding a
10 bp flanking region on each side of the footprint and then using HOMER [ 44
](/articles/s41467-021-22100-8#ref-CR44 "Heinz, S. et al. Simple combinations
of lineage-determining transcription factors prime cis-regulatory elements
required for macrophage and B cell identities. Mol. Cell 38, 576–589
\(2010\).") 4.10 with default arguments with the exception that the given
region sizes were used (default is to use 200 bp windows centered on the
middle each region) and the known vertebrate motif database provided with the
HOMER software was used in place of the default motif database.
### Prediction of target genes
To remove genes with low variance in expression, the ratio of the maximum
expression across samples to the minimum expression was compared to a cut-off
threshold. A threshold of 6 was chosen because it removed ~3800 genes from the
analysis, which is the number of housekeeping genes identified in humans by a
previous study [ 73 ](/articles/s41467-021-22100-8#ref-CR73 "Eisenberg, E. &
Levanon, E. Y. Human housekeeping genes, revisited. Trends Genet. 29, 569–574
\(2013\).") . The same threshold was used to remove distal REs with low
variance in their level of enrichment from the analysis.
TADs in each species were predicted using pooled CTCF ChIP-seq data from all
tissues, as previous studies have suggested that while chromatin interactions
within TADs may differ across cell types, the TAD boundaries themselves are
stable across tissues [ 74 ](/articles/s41467-021-22100-8#ref-CR74 "Lonfat,
N. & Duboule, D. Structure, function and evolution of topologically
associating domains \(TADs\) at HOX loci. FEBS Lett. 589, 2869–2876
\(2015\).") and even species [ 75 ](/articles/s41467-021-22100-8#ref-CR75
"Krefting, J., Andrade-Navarro, M. A. & Ibn-Salem, J. Evolutionary stability
of topologically associating domains is associated with conserved gene
regulation. BMC Biol. 16, 87 \(2018\).") , [ 76
](/articles/s41467-021-22100-8#ref-CR76 "Wang, M. et al. Putative bovine
topological association domains and CTCF binding motifs can reduce the search
space for causative regulatory variants of complex traits. BMC Genom. 19, 395
\(2018\).") . TADs were predicted from CTCF ChIP-seq peaks using the method in
Oti et al. [ 77 ](/articles/s41467-021-22100-8#ref-CR77 "Oti, M., Falck, J.,
Huynen, M. A. & Zhou, H. CTCF-mediated chromatin loops enclose inducible gene
regulatory domains. BMC Genom. 17, 252 \(2016\).") . Briefly, the CTCF peaks
from all tissues were merged, then FIMO [ 78
](/articles/s41467-021-22100-8#ref-CR78 "Grant, C. E., Bailey, T. L. & Noble,
W. S. FIMO: scanning for occurrences of a given motif. Bioinformatics 27,
1017–1018 \(2011\).") was used to identify peaks containing the CTCF-binding
motif. The directionality of the motif within peaks was used to match
corresponding boundaries of DNA loops. Nested and overlapping loops were then
merged to form the predicted TADs.
To predict RE–gene pairs, the Spearman rank correlation of every possible
combination of regulatory element H3K27ac signal and gene expression value
within each TAD was calculated. The gene expression value used was the TMM-
normalized CPM described previously, and the H3K27ac signal was calculated by
TMM-normalizing the number of H3K27ac reads aligning to each RE using the same
method to normalize gene expression values. Benjamini–Hochberg adjustment was
used to adjust the _p_ -values for multiple testing, and adjusted _p_ -values
< 0.05 were considered indicative of putative interacting pairs.
### Overlap analysis of REs with SNPs from dairy cattle GWAS study
Imputed sequence variants obtained from GWAS on dairy cattle traits from a
previous study were mapped from the UMD-3.1 version of the cattle genome to
the UCD-ARS1.2 version used in this paper using the UCSC liftOver tool [ 79
](/articles/s41467-021-22100-8#ref-CR79 "Kent, W. J. et al. The human genome
browser at UCSC. Genome Res. 12, 996–1006 \(2002\).") with default parameters.
SNPs were then checked for their presence within REs using BEDTools [ 68
](/articles/s41467-021-22100-8#ref-CR68 "Quinlan, A. R. & Hall, I. M.
BEDTools: a flexible suite of utilities for comparing genomic features.
Bioinformatics 26, 841–842 \(2010\).") .
### Reporting summary
Further information on research design is available in the [ Nature Research
Reporting Summary ](/articles/s41467-021-22100-8#MOESM7) linked to this
article.
## Data availability
Raw sequencing data and processed data has been deposited in the Gene
Expression Omnibus (GEO) and is available under accession [ GSE158430
](https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE158430) . Accession
numbers for ENCODE and Roadmap datasets used are given as Supplementary Data [
3 ](/articles/s41467-021-22100-8#MOESM6) . Aligned and filtered reads, peak
calls, chromatin state predictions, and identified regulatory elements are
available at [ http://farm.cse.ucdavis.edu/~ckern/Nature_Communications_2020/.
Source data are provided with this paper
](http://farm.cse.ucdavis.edu/~ckern/Nature_Communications_2020/) . [ Source
data ](/articles/s41467-021-22100-8#Sec22) are provided with this paper.
## Code availability
The computational pipeline used for the analyses in this manuscript is
available in GitHub [ 80 ](/articles/s41467-021-22100-8#ref-CR80 "Kern, C. E.
A. Functional Annotations of Three Domestic Animal Genomes Provide Vital
Resources for Comparative and Agricultural Research.
https://github.com/kernco/functional-annotation
,
https://doi.org/10.5281/zenodo.4540293
\(2021\).") ( [ https://github.com/kernco/functional-annotation ](https://github.com/kernco/functional-annotation) ).
## References
1. Adesogan, A. T., Havelaar, A. H., McKune, S. L., Eilittä, M. & Dahl, G. E. Animal source foods: sustainability problem or malnutrition and sustainability solution? Perspective matters. _Glob. Food Secur._ **25** , 100325 (2020).
[ Article ](https://doi.org/10.1016%2Fj.gfs.2019.100325) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Animal%20source%20foods%3A%20sustainability%20problem%20or%20malnutrition%20and%20sustainability%20solution%3F%20Perspective%20matters&journal=Glob.%20Food%20Secur.&doi=10.1016%2Fj.gfs.2019.100325&volume=25&publication_year=2020&author=Adesogan%2CAT&author=Havelaar%2CAH&author=McKune%2CSL&author=Eilitt%C3%A4%2CM&author=Dahl%2CGE)
2. Wallis, J. W. et al. A physical map of the chicken genome. _Nature_ **432** , 761–764 (2004).
[ Article ](https://doi.org/10.1038%2Fnature03030) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2004Natur.432..761W) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD2cXhtVGmtLjF) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=15592415)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=A%20physical%20map%20of%20the%20chicken%20genome&journal=Nature&doi=10.1038%2Fnature03030&volume=432&pages=761-764&publication_year=2004&author=Wallis%2CJW)
3. Hindorff, L. A. et al. Potential etiologic and functional implications of genome-wide association loci for human diseases and traits. _Proc. Natl Acad. Sci. USA_ **106** , 9362–9367 (2009).
[ Article ](https://doi.org/10.1073%2Fpnas.0903103106) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2009PNAS..106.9362H) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD1MXot1Cgur4%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=19474294)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2687147) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Potential%20etiologic%20and%20functional%20implications%20of%20genome-
wide%20association%20loci%20for%20human%20diseases%20and%20traits&journal=Proc.%20Natl%20Acad.%20Sci.%20USA&doi=10.1073%2Fpnas.0903103106&volume=106&pages=9362-9367&publication_year=2009&author=Hindorff%2CLA)
4. Consortium, E. P. The ENCODE (ENCyclopedia Of DNA Elements) Project. _Science_ **306** , 636–640 (2004).
[ Article ](https://doi.org/10.1126%2Fscience.1105136) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2004Sci...306..636E) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD2cXos1KqtLc%3D) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20ENCODE%20%28ENCyclopedia%20Of%20DNA%20Elements%29%20Project&journal=Science&doi=10.1126%2Fscience.1105136&volume=306&pages=636-640&publication_year=2004&author=Consortium%2CEP)
5. Stamatoyannopoulos, J. A. et al. An encyclopedia of mouse DNA elements (Mouse ENCODE). _Genome Biol._ **13** , 1–5 (2012).
[ CAS ](/articles/cas-redirect/1:CAS:528:DC%2BC38XltVeqt7s%3D) [ Google
Scholar
](http://scholar.google.com/scholar_lookup?&title=An%20encyclopedia%20of%20mouse%20DNA%20elements%20%28Mouse%20ENCODE%29&journal=Genome%20Biol.&volume=13&pages=1-5&publication_year=2012&author=Stamatoyannopoulos%2CJA)
6. Consortium, E. P. An integrated encyclopedia of DNA elements in the human genome. _Nature_ **489** , 57–74 (2012).
[ Article ](https://doi.org/10.1038%2Fnature11247) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2012Natur.489...57T) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC38XhtlGnsbzN) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=An%20integrated%20encyclopedia%20of%20DNA%20elements%20in%20the%20human%20genome&journal=Nature&doi=10.1038%2Fnature11247&volume=489&pages=57-74&publication_year=2012&author=Consortium%2CEP)
7. Maurano, M. T. et al. Systematic localization of common disease-associated variation in regulatory DNA. _Science_ **337** , 1190–1195 (2012).
[ Article ](https://doi.org/10.1126%2Fscience.1222794) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2012Sci...337.1190M) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC38Xht1ylsLfL) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=22955828)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3771521) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Systematic%20localization%20of%20common%20disease-
associated%20variation%20in%20regulatory%20DNA&journal=Science&doi=10.1126%2Fscience.1222794&volume=337&pages=1190-1195&publication_year=2012&author=Maurano%2CMT)
8. Kundaje, A. et al. Integrative analysis of 111 reference human epigenomes. _Nature_ **518** , 317–330 (2015).
[ Article ](https://doi.org/10.1038%2Fnature14248) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC2MXjtVSktbc%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25693563)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4530010) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Integrative%20analysis%20of%20111%20reference%20human%20epigenomes&journal=Nature&doi=10.1038%2Fnature14248&volume=518&pages=317-330&publication_year=2015&author=Kundaje%2CA)
9. Abascal, F. et al. Perspectives on ENCODE. _Nature_ **583** , 693–698 (2020).
[ Article ](https://doi.org/10.1038%2Fs41586-020-2449-8) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BB3cXhsVygtLnO) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Perspectives%20on%20ENCODE&journal=Nature&doi=10.1038%2Fs41586-020-2449-8&volume=583&pages=693-698&publication_year=2020&author=Abascal%2CF)
10. Gorkin, D. U. et al. An atlas of dynamic chromatin landscapes in mouse fetal development. _Nature_ **583** , 744–751 (2020).
[ Article ](https://doi.org/10.1038%2Fs41586-020-2093-3) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2020Natur.583..744G) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BB3cXhsVygtLnJ) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32728240)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7398618) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=An%20atlas%20of%20dynamic%20chromatin%20landscapes%20in%20mouse%20fetal%20development&journal=Nature&doi=10.1038%2Fs41586-020-2093-3&volume=583&pages=744-751&publication_year=2020&author=Gorkin%2CDU)
11. Janes, D. E. et al. Reptiles and mammals have differentially retained long conserved noncoding sequences from the amniote ancestor. _Genome Biol. Evol._ **3** , 102–113 (2011).
[ Article ](https://doi.org/10.1093%2Fgbe%2Fevq087) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC3MXisVejsbk%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21183607)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Reptiles%20and%20mammals%20have%20differentially%20retained%20long%20conserved%20noncoding%20sequences%20from%20the%20amniote%20ancestor&journal=Genome%20Biol.%20Evol.&doi=10.1093%2Fgbe%2Fevq087&volume=3&pages=102-113&publication_year=2011&author=Janes%2CDE)
12. Sackton, T. B. et al. Convergent regulatory evolution and loss of flight in paleognathous birds. _Science_ **364** , 74 (2019).
[ Article ](https://doi.org/10.1126%2Fscience.aat7244) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2019Sci...364...74S) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC1MXmsVSnurk%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=30948549)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Convergent%20regulatory%20evolution%20and%20loss%20of%20flight%20in%20paleognathous%20birds&journal=Science&doi=10.1126%2Fscience.aat7244&volume=364&publication_year=2019&author=Sackton%2CTB)
13. Lowe, C. B., Clarke, J. A., Baker, A. J., Haussler, D. & Edwards, S. V. Feather development genes and associated regulatory innovation predate the origin of Dinosauria. _Mol. Biol. Evol._ **32** , 23–28 (2015).
[ Article ](https://doi.org/10.1093%2Fmolbev%2Fmsu309) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC2MXivFGlsL0%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25415961)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Feather%20development%20genes%20and%20associated%20regulatory%20innovation%20predate%20the%20origin%20of%20Dinosauria&journal=Mol.%20Biol.%20Evol.&doi=10.1093%2Fmolbev%2Fmsu309&volume=32&pages=23-28&publication_year=2015&author=Lowe%2CCB&author=Clarke%2CJA&author=Baker%2CAJ&author=Haussler%2CD&author=Edwards%2CSV)
14. Seki, R. et al. Functional roles of Aves class-specific cis-regulatory elements on macroevolution of bird-specific features. _Nat. Commun._ **8** , 14229 (2017).
[ Article ](https://doi.org/10.1038%2Fncomms14229) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2017NatCo...814229S) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2sXitlClurY%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=28165450)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5473641) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Functional%20roles%20of%20Aves%20class-
specific%20cis-regulatory%20elements%20on%20macroevolution%20of%20bird-
specific%20features&journal=Nat.%20Commun.&doi=10.1038%2Fncomms14229&volume=8&publication_year=2017&author=Seki%2CR)
15. Lekven, A. C. et al. Analysis of the wnt1 regulatory chromosomal landscape. _Dev. Genes Evol._ **229** , 43–52 (2019).
[ Article ](https://link.springer.com/doi/10.1007/s00427-019-00629-5) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC1MXotlWksbc%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=30825002)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6500750) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Analysis%20of%20the%20wnt1%20regulatory%20chromosomal%20landscape&journal=Dev.%20Genes%20Evol.&doi=10.1007%2Fs00427-019-00629-5&volume=229&pages=43-52&publication_year=2019&author=Lekven%2CAC)
16. Foissac, S. et al. Multi-species annotation of transcriptome and chromatin structure in domesticated animals. _BMC Biol._ **17** , 108 (2019).
[ Article ](https://link.springer.com/doi/10.1186/s12915-019-0726-5) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BB3cXivVSgug%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=31884969)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6936065) [
Google Scholar ](http://scholar.google.com/scholar_lookup?&title=Multi-
species%20annotation%20of%20transcriptome%20and%20chromatin%20structure%20in%20domesticated%20animals&journal=BMC%20Biol.&doi=10.1186%2Fs12915-019-0726-5&volume=17&publication_year=2019&author=Foissac%2CS)
17. Artemov, A. V. et al. Genome-wide DNA methylation profiling reveals epigenetic adaptation of stickleback to marine and freshwater conditions. _Mol. Biol. Evol._ **34** , 2203–2213 (2017).
[ Article ](https://doi.org/10.1093%2Fmolbev%2Fmsx156) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC1cXhvFaru77L) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=28873953)
[ Google Scholar ](http://scholar.google.com/scholar_lookup?&title=Genome-
wide%20DNA%20methylation%20profiling%20reveals%20epigenetic%20adaptation%20of%20stickleback%20to%20marine%20and%20freshwater%20conditions&journal=Mol.%20Biol.%20Evol.&doi=10.1093%2Fmolbev%2Fmsx156&volume=34&pages=2203-2213&publication_year=2017&author=Artemov%2CAV)
18. Andersson, L. et al. Coordinated international action to accelerate genome-to-phenome with FAANG, the Functional Annotation of Animal Genomes project. _Genome Biol._ **16** , 57 (2015).
[ Article ](https://link.springer.com/doi/10.1186/s13059-015-0622-4) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25854118)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4373242) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2MXmvFCgtLo%3D) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Coordinated%20international%20action%20to%20accelerate%20genome-
to-
phenome%20with%20FAANG%2C%20the%20Functional%20Annotation%20of%20Animal%20Genomes%20project&journal=Genome%20Biol.&doi=10.1186%2Fs13059-015-0622-4&volume=16&publication_year=2015&author=Andersson%2CL)
19. Tuggle, C. K. et al. GO-FAANG meeting: a gathering on Functional Annotation of Animal Genomes. _Anim. Genet._ **47** , 528–533 (2016).
[ Article ](https://doi.org/10.1111%2Fage.12466) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27453069)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5082551) [
Google Scholar ](http://scholar.google.com/scholar_lookup?&title=GO-
FAANG%20meeting%3A%20a%20gathering%20on%20Functional%20Annotation%20of%20Animal%20Genomes&journal=Anim.%20Genet.&doi=10.1111%2Fage.12466&volume=47&pages=528-533&publication_year=2016&author=Tuggle%2CCK)
20. Burns, E. N. et al. Generation of an equine biobank to be used for Functional Annotation of Animal Genomes project. _Anim. Genet._ **49** , 564–570 (2018).
[ Article ](https://doi.org/10.1111%2Fage.12717) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC1cXitFyhtr%2FE) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=30311254)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6264908) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Generation%20of%20an%20equine%20biobank%20to%20be%20used%20for%20Functional%20Annotation%20of%20Animal%20Genomes%20project&journal=Anim.%20Genet.&doi=10.1111%2Fage.12717&volume=49&pages=564-570&publication_year=2018&author=Burns%2CEN)
21. Kingsley, B. N. et al. Functionally annotating regulatory elements in the equine genome using histone mark ChIP-Seq. _Genes_ **11** , [ https://doi.org/10.3390/genes11010003 ](https://doi.org/10.3390/genes11010003) (2019).
22. Giuffra, E. & Tuggle, C. K. Functional Annotation of Animal Genomes (FAANG): current achievements and roadmap. _Annu. Rev. Anim. Biosci._ **7** , 65–88 (2019).
[ Article ](https://doi.org/10.1146%2Fannurev-animal-020518-114913) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC1cXit1SntrzK) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=30427726)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Functional%20Annotation%20of%20Animal%20Genomes%20%28FAANG%29%3A%20current%20achievements%20and%20roadmap&journal=Annu.%20Rev.%20Anim.%20Biosci.&doi=10.1146%2Fannurev-
animal-020518-114913&volume=7&pages=65-88&publication_year=2019&author=Giuffra%2CE&author=Tuggle%2CCK)
23. Halstead, M. M. et al. A comparative analysis of chromatin accessibility in cattle, pig, and mouse tissues. _BMC Genom._ **21** , 698 (2020).
[ Article ](https://link.springer.com/doi/10.1186/s12864-020-07078-9) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BB3cXitVagsbzO) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=A%20comparative%20analysis%20of%20chromatin%20accessibility%20in%20cattle%2C%20pig%2C%20and%20mouse%20tissues&journal=BMC%20Genom.&doi=10.1186%2Fs12864-020-07078-9&volume=21&publication_year=2020&author=Halstead%2CMM)
24. Clark, E. L. et al. From FAANG to fork: application of highly annotated genomes to improve farmed animal production. _Genome Biol._ **21** , 285 (2020).
[ Article ](https://link.springer.com/doi/10.1186/s13059-020-02197-8) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=33234160)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7686664) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=From%20FAANG%20to%20fork%3A%20application%20of%20highly%20annotated%20genomes%20to%20improve%20farmed%20animal%20production&journal=Genome%20Biol.&doi=10.1186%2Fs13059-020-02197-8&volume=21&publication_year=2020&author=Clark%2CEL)
25. Stergachis, A. B. et al. Conservation of trans-acting circuitry during mammalian regulatory evolution. _Nature_ **515** , 365–370 (2014).
[ Article ](https://doi.org/10.1038%2Fnature13972) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2014Natur.515..365S) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2cXhvFGlt73K) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25409825)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4405208) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Conservation%20of%20trans-
acting%20circuitry%20during%20mammalian%20regulatory%20evolution&journal=Nature&doi=10.1038%2Fnature13972&volume=515&pages=365-370&publication_year=2014&author=Stergachis%2CAB)
26. Cheng, Y. et al. Principles of regulatory information conservation between mouse and human. _Nature_ **515** , 371–375 (2014).
[ Article ](https://doi.org/10.1038%2Fnature13985) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2014Natur.515..371C) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2cXhvFGlt7rO) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25409826)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4343047) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Principles%20of%20regulatory%20information%20conservation%20between%20mouse%20and%20human&journal=Nature&doi=10.1038%2Fnature13985&volume=515&pages=371-375&publication_year=2014&author=Cheng%2CY)
27. Johnson, D. S., Mortazavi, A., Myers, R. M. & Wold, B. Genome-wide mapping of in vivo protein-DNA interactions. _Science_ **316** , 1497–1502 (2007).
[ Article ](https://doi.org/10.1126%2Fscience.1141319) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2007Sci...316.1497J) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD2sXmtFSjtrg%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=17540862)
[ Google Scholar ](http://scholar.google.com/scholar_lookup?&title=Genome-
wide%20mapping%20of%20in%20vivo%20protein-
DNA%20interactions&journal=Science&doi=10.1126%2Fscience.1141319&volume=316&pages=1497-1502&publication_year=2007&author=Johnson%2CDS&author=Mortazavi%2CA&author=Myers%2CRM&author=Wold%2CB)
28. Barski, A. et al. High-resolution profiling of histone methylations in the human genome. _Cell_ **129** , 823–837 (2007).
[ Article ](https://doi.org/10.1016%2Fj.cell.2007.05.009) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD2sXmtFKjsro%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=17512414)
[ Google Scholar ](http://scholar.google.com/scholar_lookup?&title=High-
resolution%20profiling%20of%20histone%20methylations%20in%20the%20human%20genome&journal=Cell&doi=10.1016%2Fj.cell.2007.05.009&volume=129&pages=823-837&publication_year=2007&author=Barski%2CA)
29. Crawford, G. E. et al. Genome-wide mapping of DNase hypersensitive sites using massively parallel signature sequencing (MPSS). _Genome Res._ **16** , 123–131 (2006).
[ Article ](https://doi.org/10.1101%2Fgr.4074106) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BD28XhslChtb8%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=16344561)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1356136) [
Google Scholar ](http://scholar.google.com/scholar_lookup?&title=Genome-
wide%20mapping%20of%20DNase%20hypersensitive%20sites%20using%20massively%20parallel%20signature%20sequencing%20%28MPSS%29&journal=Genome%20Res.&doi=10.1101%2Fgr.4074106&volume=16&pages=123-131&publication_year=2006&author=Crawford%2CGE)
30. Buenrostro, J. D., Giresi, P. G., Zaba, L. C., Chang, H. Y. & Greenleaf, W. J. Transposition of native chromatin for fast and sensitive epigenomic profiling of open chromatin, DNA-binding proteins and nucleosome position. _Nat. Methods_ **10** , 1213–1218 (2013).
[ Article ](https://doi.org/10.1038%2Fnmeth.2688) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC3sXhsFOiu7jO) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=24097267)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3959825) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Transposition%20of%20native%20chromatin%20for%20fast%20and%20sensitive%20epigenomic%20profiling%20of%20open%20chromatin%2C%20DNA-
binding%20proteins%20and%20nucleosome%20position&journal=Nat.%20Methods&doi=10.1038%2Fnmeth.2688&volume=10&pages=1213-1218&publication_year=2013&author=Buenrostro%2CJD&author=Giresi%2CPG&author=Zaba%2CLC&author=Chang%2CHY&author=Greenleaf%2CWJ)
31. Landt, S. G. et al. ChIP-seq guidelines and practices of the ENCODE and modENCODE consortia. _Genome Res._ **22** , 1813–1831 (2012).
[ Article ](https://doi.org/10.1101%2Fgr.136184.111) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC38XhtlentLvJ) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=22955991)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3431496) [
Google Scholar ](http://scholar.google.com/scholar_lookup?&title=ChIP-
seq%20guidelines%20and%20practices%20of%20the%20ENCODE%20and%20modENCODE%20consortia&journal=Genome%20Res.&doi=10.1101%2Fgr.136184.111&volume=22&pages=1813-1831&publication_year=2012&author=Landt%2CSG)
32. Ernst, J. & Kellis, M. ChromHMM: automating chromatin-state discovery and characterization. _Nat. Methods_ **9** , 215–216 (2012).
[ Article ](https://doi.org/10.1038%2Fnmeth.1906) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC38XivV2rtLk%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=22373907)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3577932) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=ChromHMM%3A%20automating%20chromatin-
state%20discovery%20and%20characterization&journal=Nat.%20Methods&doi=10.1038%2Fnmeth.1906&volume=9&pages=215-216&publication_year=2012&author=Ernst%2CJ&author=Kellis%2CM)
33. Hoffman, M. M. et al. Integrative annotation of chromatin elements from ENCODE data. _Nucleic Acids Res._ **41** , 827–841 (2012).
[ Article ](https://doi.org/10.1093%2Fnar%2Fgks1284) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=23221638)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3553955) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3sXhtFyisr0%3D) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Integrative%20annotation%20of%20chromatin%20elements%20from%20ENCODE%20data&journal=Nucleic%20Acids%20Res.&doi=10.1093%2Fnar%2Fgks1284&volume=41&pages=827-841&publication_year=2012&author=Hoffman%2CMM)
34. Guenther, M. G., Levine, S. S., Boyer, L. A., Jaenisch, R. & Young, R. A. A chromatin landmark and transcription initiation at most promoters in human cells. _Cell_ **130** , 77–88 (2007).
[ Article ](https://doi.org/10.1016%2Fj.cell.2007.05.042) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD2sXotlGmtrk%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=17632057)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3200295) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=A%20chromatin%20landmark%20and%20transcription%20initiation%20at%20most%20promoters%20in%20human%20cells&journal=Cell&doi=10.1016%2Fj.cell.2007.05.042&volume=130&pages=77-88&publication_year=2007&author=Guenther%2CMG&author=Levine%2CSS&author=Boyer%2CLA&author=Jaenisch%2CR&author=Young%2CRA)
35. Mikkelsen, T. S. et al. Genome-wide maps of chromatin state in pluripotent and lineage-committed cells. _Nature_ **448** , 553–560 (2007).
[ Article ](https://doi.org/10.1038%2Fnature06008) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2007Natur.448..553M) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD2sXosVSrtrc%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=17603471)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2921165) [
Google Scholar ](http://scholar.google.com/scholar_lookup?&title=Genome-
wide%20maps%20of%20chromatin%20state%20in%20pluripotent%20and%20lineage-
committed%20cells&journal=Nature&doi=10.1038%2Fnature06008&volume=448&pages=553-560&publication_year=2007&author=Mikkelsen%2CTS)
36. Nègre, N. et al. A cis-regulatory map of the Drosophila genome. _Nature_ **471** , 527–531 (2011).
[ Article ](https://doi.org/10.1038%2Fnature09990) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2011Natur.471..527N) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21430782)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3179250) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3MXjvVOhu7o%3D) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=A%20cis-
regulatory%20map%20of%20the%20Drosophila%20genome&journal=Nature&doi=10.1038%2Fnature09990&volume=471&pages=527-531&publication_year=2011&author=N%C3%A8gre%2CN)
37. Creyghton, M. P. et al. Histone H3K27ac separates active from poised enhancers and predicts developmental state. _Proc. Natl Acad. Sci. USA_ **107** , 21931 (2010).
[ Article ](https://doi.org/10.1073%2Fpnas.1016071107) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2010PNAS..10721931C) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3cXhs1Wjs7bP) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21106759)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3003124) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Histone%20H3K27ac%20separates%20active%20from%20poised%20enhancers%20and%20predicts%20developmental%20state&journal=Proc.%20Natl%20Acad.%20Sci.%20USA&doi=10.1073%2Fpnas.1016071107&volume=107&publication_year=2010&author=Creyghton%2CMP)
38. Ernst, J. et al. Mapping and analysis of chromatin state dynamics in nine human cell types. _Nature_ **473** , 43 (2011).
[ Article ](https://doi.org/10.1038%2Fnature09906) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2011Natur.473...43E) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3MXjvVOitL0%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21441907)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3088773) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Mapping%20and%20analysis%20of%20chromatin%20state%20dynamics%20in%20nine%20human%20cell%20types&journal=Nature&doi=10.1038%2Fnature09906&volume=473&publication_year=2011&author=Ernst%2CJ)
39. Botero-Castro, F., Figuet, E., Tilak, M. K., Nabholz, B. & Galtier, N. Avian Genomes Revisited: Hidden Genes Uncovered and the Rates versus Traits Paradox in Birds. _Mol. Biol. Evol._ **34** , 3123–3131 (2017).
40. Yue, F. et al. A comparative encyclopedia of DNA elements in the mouse genome. _Nature_ **515** , 355–364 (2014).
[ Article ](https://doi.org/10.1038%2Fnature13992) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC2cXhvFGlt7rI) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25409824)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4266106) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=A%20comparative%20encyclopedia%20of%20DNA%20elements%20in%20the%20mouse%20genome&journal=Nature&doi=10.1038%2Fnature13992&volume=515&pages=355-364&publication_year=2014&author=Yue%2CF)
41. He, Q. et al. High conservation of transcription factor binding and evidence for combinatorial regulation across six Drosophila species. _Nat. Genet._ **43** , 414–420 (2011).
[ Article ](https://doi.org/10.1038%2Fng.808) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC3MXksFWns7w%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21478888)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=High%20conservation%20of%20transcription%20factor%20binding%20and%20evidence%20for%20combinatorial%20regulation%20across%20six%20Drosophila%20species&journal=Nat.%20Genet.&doi=10.1038%2Fng.808&volume=43&pages=414-420&publication_year=2011&author=He%2CQ)
42. Kanehisa, M. & Goto, S. KEGG: kyoto encyclopedia of genes and genomes. _Nucleic Acids Res._ **28** , 27–30 (2000).
[ Article ](https://doi.org/10.1093%2Fnar%2F28.1.27) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BD3cXhvVGqu74%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=10592173)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC102409) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=KEGG%3A%20kyoto%20encyclopedia%20of%20genes%20and%20genomes&journal=Nucleic%20Acids%20Res.&doi=10.1093%2Fnar%2F28.1.27&volume=28&pages=27-30&publication_year=2000&author=Kanehisa%2CM&author=Goto%2CS)
43. Neph, S. et al. An expansive human regulatory lexicon encoded in transcription factor footprints. _Nature_ **489** , 83–90 (2012).
[ Article ](https://doi.org/10.1038%2Fnature11212) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2012Natur.489...83N) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC38XhtlGnsLzL) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=22955618)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3736582) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=An%20expansive%20human%20regulatory%20lexicon%20encoded%20in%20transcription%20factor%20footprints&journal=Nature&doi=10.1038%2Fnature11212&volume=489&pages=83-90&publication_year=2012&author=Neph%2CS)
44. Heinz, S. et al. Simple combinations of lineage-determining transcription factors prime cis-regulatory elements required for macrophage and B cell identities. _Mol. Cell_ **38** , 576–589 (2010).
[ Article ](https://doi.org/10.1016%2Fj.molcel.2010.05.004) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3cXns1SlsLc%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=20513432)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2898526) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Simple%20combinations%20of%20lineage-
determining%20transcription%20factors%20prime%20cis-
regulatory%20elements%20required%20for%20macrophage%20and%20B%20cell%20identities&journal=Mol.%20Cell&doi=10.1016%2Fj.molcel.2010.05.004&volume=38&pages=576-589&publication_year=2010&author=Heinz%2CS)
45. Smith, R. P. et al. Massively parallel decoding of mammalian regulatory sequences supports a flexible organizational model. _Nat. Genet._ **45** , 1021–1028 (2013).
[ Article ](https://doi.org/10.1038%2Fng.2713) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC3sXhtFOhsb7P) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=23892608)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3775494) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Massively%20parallel%20decoding%20of%20mammalian%20regulatory%20sequences%20supports%20a%20flexible%20organizational%20model&journal=Nat.%20Genet.&doi=10.1038%2Fng.2713&volume=45&pages=1021-1028&publication_year=2013&author=Smith%2CRP)
46. Wu, W. et al. The role of Six1 in the genesis of muscle cell and skeletal muscle development. _Int. J. Biol. Sci._ **10** , 983–989 (2014).
[ Article ](https://doi.org/10.7150%2Fijbs.9442) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25210496)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159689) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2cXitFGmsrrP) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20role%20of%20Six1%20in%20the%20genesis%20of%20muscle%20cell%20and%20skeletal%20muscle%20development&journal=Int.%20J.%20Biol.%20Sci.&doi=10.7150%2Fijbs.9442&volume=10&pages=983-989&publication_year=2014&author=Wu%2CW)
47. Dixon, J. R. et al. Topological domains in mammalian genomes identified by analysis of chromatin interactions. _Nature_ **485** , 376–380 (2012).
[ Article ](https://doi.org/10.1038%2Fnature11082) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2012Natur.485..376D) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC38XlslShurw%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=22495300)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356448) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Topological%20domains%20in%20mammalian%20genomes%20identified%20by%20analysis%20of%20chromatin%20interactions&journal=Nature&doi=10.1038%2Fnature11082&volume=485&pages=376-380&publication_year=2012&author=Dixon%2CJR)
48. Rao, S. S. et al. A 3D map of the human genome at kilobase resolution reveals principles of chromatin looping. _Cell_ **159** , 1665–1680 (2014).
[ Article ](https://doi.org/10.1016%2Fj.cell.2014.11.021) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2cXitFCrtrrK) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25497547)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5635824) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=A%203D%20map%20of%20the%20human%20genome%20at%20kilobase%20resolution%20reveals%20principles%20of%20chromatin%20looping&journal=Cell&doi=10.1016%2Fj.cell.2014.11.021&volume=159&pages=1665-1680&publication_year=2014&author=Rao%2CSS)
49. Kvon, E. Z. et al. Genome-scale functional characterization of Drosophila developmental enhancers in vivo. _Nature_ **512** , 91–95 (2014).
[ Article ](https://doi.org/10.1038%2Fnature13395) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2014Natur.512...91K) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2cXpslGiu74%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=24896182)
[ Google Scholar ](http://scholar.google.com/scholar_lookup?&title=Genome-
scale%20functional%20characterization%20of%20Drosophila%20developmental%20enhancers%20in%20vivo&journal=Nature&doi=10.1038%2Fnature13395&volume=512&pages=91-95&publication_year=2014&author=Kvon%2CEZ)
50. Zhang, Y. et al. Chromatin connectivity maps reveal dynamic promoter–enhancer long-range associations. _Nature_ **504** , 306–310 (2013).
[ Article ](https://doi.org/10.1038%2Fnature12716) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2013Natur.504..306Z) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3sXhvFaqsr%2FF) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=24213634)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3954713) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Chromatin%20connectivity%20maps%20reveal%20dynamic%20promoter%E2%80%93enhancer%20long-
range%20associations&journal=Nature&doi=10.1038%2Fnature12716&volume=504&pages=306-310&publication_year=2013&author=Zhang%2CY)
51. Lettice, L. A. et al. A long-range Shh enhancer regulates expression in the developing limb and fin and is associated with preaxial polydactyly. _Hum. Mol. Genet._ **12** , 1725–1735 (2003).
[ Article ](https://doi.org/10.1093%2Fhmg%2Fddg180) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BD3sXltFygsrg%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=12837695)
[ Google Scholar ](http://scholar.google.com/scholar_lookup?&title=A%20long-
range%20Shh%20enhancer%20regulates%20expression%20in%20the%20developing%20limb%20and%20fin%20and%20is%20associated%20with%20preaxial%20polydactyly&journal=Hum.%20Mol.%20Genet.&doi=10.1093%2Fhmg%2Fddg180&volume=12&pages=1725-1735&publication_year=2003&author=Lettice%2CLA)
52. Karlić, R., Chung, H.-R., Lasserre, J., Vlahoviček, K. & Vingron, M. Histone modification levels are predictive for gene expression. _Proc. Natl Acad. Sci. USA_ **107** , 2926 (2010).
[ Article ](https://doi.org/10.1073%2Fpnas.0909344107) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2010PNAS..107.2926K) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=20133639)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2814872) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Histone%20modification%20levels%20are%20predictive%20for%20gene%20expression&journal=Proc.%20Natl%20Acad.%20Sci.%20USA&doi=10.1073%2Fpnas.0909344107&volume=107&publication_year=2010&author=Karli%C4%87%2CR&author=Chung%2CH-R&author=Lasserre%2CJ&author=Vlahovi%C4%8Dek%2CK&author=Vingron%2CM)
53. Zhang, Z. & Zhang, M. Q. Histone modification profiles are predictive for tissue/cell-type specific expression of both protein-coding and microRNA genes. _BMC Bioinforma._ **12** , 155 (2011).
[ Article ](https://link.springer.com/doi/10.1186/1471-2105-12-155) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3MXmsV2iu7w%3D) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Histone%20modification%20profiles%20are%20predictive%20for%20tissue%2Fcell-
type%20specific%20expression%20of%20both%20protein-
coding%20and%20microRNA%20genes&journal=BMC%20Bioinforma.&doi=10.1186%2F1471-2105-12-155&volume=12&publication_year=2011&author=Zhang%2CZ&author=Zhang%2CMQ)
54. Xiang, R. et al. Genome variants associated with RNA splicing variations in bovine are extensively shared between tissues. _BMC Genom._ **19** , 521 (2018).
[ Article ](https://link.springer.com/doi/10.1186/s12864-018-4902-8) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC1cXisVequrzJ) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Genome%20variants%20associated%20with%20RNA%20splicing%20variations%20in%20bovine%20are%20extensively%20shared%20between%20tissues&journal=BMC%20Genom.&doi=10.1186%2Fs12864-018-4902-8&volume=19&publication_year=2018&author=Xiang%2CR)
55. Xiang, R. et al. Quantifying the contribution of sequence variants with regulatory and evolutionary significance to 34 bovine complex traits. _Proc. Natl Acad. Sci. USA_ **116** , 19398 (2019).
[ Article ](https://doi.org/10.1073%2Fpnas.1904159116) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC1MXhvVGnsr7J) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=31501319)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6765237) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Quantifying%20the%20contribution%20of%20sequence%20variants%20with%20regulatory%20and%20evolutionary%20significance%20to%2034%20bovine%20complex%20traits&journal=Proc.%20Natl%20Acad.%20Sci.%20USA&doi=10.1073%2Fpnas.1904159116&volume=116&publication_year=2019&author=Xiang%2CR)
56. Kern, C. et al. Genome-wide identification of tissue-specific long non-coding RNA in three farm animal species. _BMC Genom._ **19** , 684 (2018).
[ Article ](https://link.springer.com/doi/10.1186/s12864-018-5037-7) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC1cXisFajtbjI) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Genome-
wide%20identification%20of%20tissue-specific%20long%20non-
coding%20RNA%20in%20three%20farm%20animal%20species&journal=BMC%20Genom.&doi=10.1186%2Fs12864-018-5037-7&volume=19&publication_year=2018&author=Kern%2CC)
57. Halstead, M. M. et al. Systematic alteration of ATAC-seq for profiling open chromatin in cryopreserved nuclei preparations from livestock tissues. _Sci. Rep._ **10** , 5230–5230 (2020).
[ Article ](https://doi.org/10.1038%2Fs41598-020-61678-9) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=2020NatSR..10.5230H) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BB3cXlvFGht7Y%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32251359)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7089989) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Systematic%20alteration%20of%20ATAC-
seq%20for%20profiling%20open%20chromatin%20in%20cryopreserved%20nuclei%20preparations%20from%20livestock%20tissues&journal=Sci.%20Rep.&doi=10.1038%2Fs41598-020-61678-9&volume=10&pages=5230-5230&publication_year=2020&author=Halstead%2CMM)
58. John, S. et al. Chromatin accessibility pre-determines glucocorticoid receptor binding patterns. _Nat. Genet._ **43** , 264–268 (2011).
[ Article ](https://doi.org/10.1038%2Fng.759) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC3MXps1ajsA%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21258342)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6386452) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Chromatin%20accessibility%20pre-
determines%20glucocorticoid%20receptor%20binding%20patterns&journal=Nat.%20Genet.&doi=10.1038%2Fng.759&volume=43&pages=264-268&publication_year=2011&author=John%2CS)
59. Dobin, A. et al. STAR: ultrafast universal RNA-seq aligner. _Bioinformatics_ **29** , 15–21 (2012).
[ Article ](https://doi.org/10.1093%2Fbioinformatics%2Fbts635) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=23104886)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3530905) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC38XhvV2gsbnF) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=STAR%3A%20ultrafast%20universal%20RNA-
seq%20aligner&journal=Bioinformatics&doi=10.1093%2Fbioinformatics%2Fbts635&volume=29&pages=15-21&publication_year=2012&author=Dobin%2CA)
60. Li, H. et al. The Sequence Alignment/Map format and SAMtools. _Bioinformatics_ **25** , 2078–2079 (2009).
[ Article ](https://doi.org/10.1093%2Fbioinformatics%2Fbtp352) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=19505943)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2723002) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD1MXpslertr8%3D) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20Sequence%20Alignment%2FMap%20format%20and%20SAMtools&journal=Bioinformatics&doi=10.1093%2Fbioinformatics%2Fbtp352&volume=25&pages=2078-2079&publication_year=2009&author=Li%2CH)
61. Anders, S., Pyl, P. T. & Huber, W. HTSeq—a Python framework to work with high-throughput sequencing data. _Bioinformatics_ **31** , 166–169 (2014).
[ Article ](https://doi.org/10.1093%2Fbioinformatics%2Fbtu638) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25260700)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4287950) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC28Xht1Sjt7vL) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=HTSeq%E2%80%94a%20Python%20framework%20to%20work%20with%20high-
throughput%20sequencing%20data&journal=Bioinformatics&doi=10.1093%2Fbioinformatics%2Fbtu638&volume=31&pages=166-169&publication_year=2014&author=Anders%2CS&author=Pyl%2CPT&author=Huber%2CW)
62. Robinson, M. D., McCarthy, D. J. & Smyth, G. K. edgeR: a Bioconductor package for differential expression analysis of digital gene expression data. _Bioinformatics_ **26** , 139–140 (2009).
[ Article ](https://doi.org/10.1093%2Fbioinformatics%2Fbtp616) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=19910308)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2796818) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD1MXhs1WlurvO) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=edgeR%3A%20a%20Bioconductor%20package%20for%20differential%20expression%20analysis%20of%20digital%20gene%20expression%20data&journal=Bioinformatics&doi=10.1093%2Fbioinformatics%2Fbtp616&volume=26&pages=139-140&publication_year=2009&author=Robinson%2CMD&author=McCarthy%2CDJ&author=Smyth%2CGK)
63. Li, H. Aligning sequence reads, clone sequences and assembly contigs with BWA-MEM. arXiv: 1303.3997 (2013).
64. Broad Institute. _Picard Toolkit_ . [ http://broadinstitute.github.io/picard/ ](http://broadinstitute.github.io/picard/) (2019).
65. Kharchenko, P. V., Tolstorukov, M. Y. & Park, P. J. Design and analysis of ChIP-seq experiments for DNA-binding proteins. _Nat. Biotechnol._ **26** , 1351–1359 (2008).
[ Article ](https://doi.org/10.1038%2Fnbt.1508) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BD1cXhsVWjtLzF) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=19029915)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2597701) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Design%20and%20analysis%20of%20ChIP-
seq%20experiments%20for%20DNA-
binding%20proteins&journal=Nat.%20Biotechnol.&doi=10.1038%2Fnbt.1508&volume=26&pages=1351-1359&publication_year=2008&author=Kharchenko%2CPV&author=Tolstorukov%2CMY&author=Park%2CPJ)
66. Ramírez, F., Dündar, F., Diehl, S., Grüning, B. A. & Manke, T. deepTools: a flexible platform for exploring deep-sequencing data. _Nucleic Acids Res._ **42** , W187–W191 (2014).
[ Article ](https://doi.org/10.1093%2Fnar%2Fgku365) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=24799436)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4086134) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2cXhtFCqs7vN) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=deepTools%3A%20a%20flexible%20platform%20for%20exploring%20deep-
sequencing%20data&journal=Nucleic%20Acids%20Res.&doi=10.1093%2Fnar%2Fgku365&volume=42&pages=W187-W191&publication_year=2014&author=Ram%C3%ADrez%2CF&author=D%C3%BCndar%2CF&author=Diehl%2CS&author=Gr%C3%BCning%2CBA&author=Manke%2CT)
67. Zhang, Y. et al. Model-based analysis of ChIP-Seq (MACS). _Genome Biol._ **9** , R137 (2008).
[ Article ](https://link.springer.com/doi/10.1186/gb-2008-9-9-r137) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=18798982)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2592715) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD1cXhtl2ksrjE) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Model-
based%20analysis%20of%20ChIP-
Seq%20%28MACS%29&journal=Genome%20Biol.&doi=10.1186%2Fgb-2008-9-9-r137&volume=9&publication_year=2008&author=Zhang%2CY)
68. Quinlan, A. R. & Hall, I. M. BEDTools: a flexible suite of utilities for comparing genomic features. _Bioinformatics_ **26** , 841–842 (2010).
[ Article ](https://doi.org/10.1093%2Fbioinformatics%2Fbtq033) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3cXivFGkurc%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=20110278)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2832824) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=BEDTools%3A%20a%20flexible%20suite%20of%20utilities%20for%20comparing%20genomic%20features&journal=Bioinformatics&doi=10.1093%2Fbioinformatics%2Fbtq033&volume=26&pages=841-842&publication_year=2010&author=Quinlan%2CAR&author=Hall%2CIM)
69. Kumar, S., Stecher, G., Suleski, M. & Hedges, S. B. TimeTree: a resource for timelines, timetrees, and divergence times. _Mol. Biol. Evol._ **34** , 1812–1819 (2017).
[ Article ](https://doi.org/10.1093%2Fmolbev%2Fmsx116) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BC1cXitFOmtrfI) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=28387841)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=TimeTree%3A%20a%20resource%20for%20timelines%2C%20timetrees%2C%20and%20divergence%20times&journal=Mol.%20Biol.%20Evol.&doi=10.1093%2Fmolbev%2Fmsx116&volume=34&pages=1812-1819&publication_year=2017&author=Kumar%2CS&author=Stecher%2CG&author=Suleski%2CM&author=Hedges%2CSB)
70. Huang, D. W., Sherman, B. T. & Lempicki, R. A. Systematic and integrative analysis of large gene lists using DAVID bioinformatics resources. _Nat. Protoc._ **4** , 44 (2008).
[ Article ](https://doi.org/10.1038%2Fnprot.2008.211) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BD1cXhsFCkurnI) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Systematic%20and%20integrative%20analysis%20of%20large%20gene%20lists%20using%20DAVID%20bioinformatics%20resources&journal=Nat.%20Protoc.&doi=10.1038%2Fnprot.2008.211&volume=4&publication_year=2008&author=Huang%2CDW&author=Sherman%2CBT&author=Lempicki%2CRA)
71. Gusmao, E. G., Allhoff, M., Zenke, M. & Costa, I. G. Analysis of computational footprinting methods for DNase sequencing experiments. _Nat. methods_ **13** , 303–309 (2016).
[ Article ](https://doi.org/10.1038%2Fnmeth.3772) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=26901649)
[ CAS ](/articles/cas-redirect/1:CAS:528:DC%2BC28XivFKhu7w%3D) [ Google
Scholar
](http://scholar.google.com/scholar_lookup?&title=Analysis%20of%20computational%20footprinting%20methods%20for%20DNase%20sequencing%20experiments&journal=Nat.%20methods&doi=10.1038%2Fnmeth.3772&volume=13&pages=303-309&publication_year=2016&author=Gusmao%2CEG&author=Allhoff%2CM&author=Zenke%2CM&author=Costa%2CIG)
72. Li, Z. et al. Identification of transcription factor binding sites using ATAC-seq. _Genome Biol._ **20** , 45 (2019).
[ Article ](https://link.springer.com/doi/10.1186/s13059-019-1642-2) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=30808370)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6391789) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Identification%20of%20transcription%20factor%20binding%20sites%20using%20ATAC-
seq&journal=Genome%20Biol.&doi=10.1186%2Fs13059-019-1642-2&volume=20&publication_year=2019&author=Li%2CZ)
73. Eisenberg, E. & Levanon, E. Y. Human housekeeping genes, revisited. _Trends Genet._ **29** , 569–574 (2013).
[ Article ](https://doi.org/10.1016%2Fj.tig.2013.05.010) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3sXhtVehurjM) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=23810203)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Human%20housekeeping%20genes%2C%20revisited&journal=Trends%20Genet.&doi=10.1016%2Fj.tig.2013.05.010&volume=29&pages=569-574&publication_year=2013&author=Eisenberg%2CE&author=Levanon%2CEY)
74. Lonfat, N. & Duboule, D. Structure, function and evolution of topologically associating domains (TADs) at HOX loci. _FEBS Lett._ **589** , 2869–2876 (2015).
[ Article ](https://doi.org/10.1016%2Fj.febslet.2015.04.024) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2MXntlWmtr8%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25913784)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Structure%2C%20function%20and%20evolution%20of%20topologically%20associating%20domains%20%28TADs%29%20at%20HOX%20loci&journal=FEBS%20Lett.&doi=10.1016%2Fj.febslet.2015.04.024&volume=589&pages=2869-2876&publication_year=2015&author=Lonfat%2CN&author=Duboule%2CD)
75. Krefting, J., Andrade-Navarro, M. A. & Ibn-Salem, J. Evolutionary stability of topologically associating domains is associated with conserved gene regulation. _BMC Biol._ **16** , 87 (2018).
[ Article ](https://link.springer.com/doi/10.1186/s12915-018-0556-x) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=30086749)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6091198) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC1MXivFWrt74%3D) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Evolutionary%20stability%20of%20topologically%20associating%20domains%20is%20associated%20with%20conserved%20gene%20regulation&journal=BMC%20Biol.&doi=10.1186%2Fs12915-018-0556-x&volume=16&publication_year=2018&author=Krefting%2CJ&author=Andrade-
Navarro%2CMA&author=Ibn-Salem%2CJ)
76. Wang, M. et al. Putative bovine topological association domains and CTCF binding motifs can reduce the search space for causative regulatory variants of complex traits. _BMC Genom._ **19** , 395 (2018).
[ Article ](https://link.springer.com/doi/10.1186/s12864-018-4800-0) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC1cXitl2ntL7L) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Putative%20bovine%20topological%20association%20domains%20and%20CTCF%20binding%20motifs%20can%20reduce%20the%20search%20space%20for%20causative%20regulatory%20variants%20of%20complex%20traits&journal=BMC%20Genom.&doi=10.1186%2Fs12864-018-4800-0&volume=19&publication_year=2018&author=Wang%2CM)
77. Oti, M., Falck, J., Huynen, M. A. & Zhou, H. CTCF-mediated chromatin loops enclose inducible gene regulatory domains. _BMC Genom._ **17** , 252 (2016).
[ Article ](https://link.springer.com/doi/10.1186/s12864-016-2516-6) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC2sXivV2lu78%3D) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=CTCF-
mediated%20chromatin%20loops%20enclose%20inducible%20gene%20regulatory%20domains&journal=BMC%20Genom.&doi=10.1186%2Fs12864-016-2516-6&volume=17&publication_year=2016&author=Oti%2CM&author=Falck%2CJ&author=Huynen%2CMA&author=Zhou%2CH)
78. Grant, C. E., Bailey, T. L. & Noble, W. S. FIMO: scanning for occurrences of a given motif. _Bioinformatics_ **27** , 1017–1018 (2011).
[ Article ](https://doi.org/10.1093%2Fbioinformatics%2Fbtr064) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3MXkt1yqs74%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21330290)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3065696) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=FIMO%3A%20scanning%20for%20occurrences%20of%20a%20given%20motif&journal=Bioinformatics&doi=10.1093%2Fbioinformatics%2Fbtr064&volume=27&pages=1017-1018&publication_year=2011&author=Grant%2CCE&author=Bailey%2CTL&author=Noble%2CWS)
79. Kent, W. J. et al. The human genome browser at UCSC. _Genome Res._ **12** , 996–1006 (2002).
[ Article ](https://doi.org/10.1101%2Fgr.229102) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BD38Xks12hs7s%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=12045153)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC186604) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20human%20genome%20browser%20at%20UCSC&journal=Genome%20Res.&doi=10.1101%2Fgr.229102&volume=12&pages=996-1006&publication_year=2002&author=Kent%2CWJ)
80. Kern, C. E. A. _Functional Annotations of Three Domestic Animal Genomes Provide Vital Resources for Comparative and Agricultural Research_ . [ https://github.com/kernco/functional-annotation ](https://github.com/kernco/functional-annotation) , [ https://doi.org/10.5281/zenodo.4540293 ](https://doi.org/10.5281/zenodo.4540293) (2021).
[ Download references ](https://citation-
needed.springer.com/v2/references/10.1038/s41467-021-22100-8?format=refman&flavour=references)
## Acknowledgements
This study was funded by Agriculture and Food Research Initiative Competitive
Grant nos. 2015-67015-22940 and 2018-67012-28026 from the USDA National
Institute of Food and Agriculture. Additional support was provided by Pork
Checkoff, Aviagen, and Multistate Research Project NRSP8 Cattle, Poultry and
Swine Coordination and NC1170 (H.Z.), and the California Agricultural
Experimental Station (H.Z.).
## Author information
### Authors and Affiliations
1. Department of Animal Science, University of California, Davis, Davis, CA, USA
Colin Kern, Ying Wang, Xiaoqin Xu, Zhangyuan Pan, Michelle Halstead, Ganrea
Chanthavixay, Perot Saelao, Susan Waters, Mary E. Delany, Juan F. Medrano,
Alison L. Van Eenennaam, Pablo Ross & Huaijun Zhou
2. Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
Ruidong Xiang
3. Agriculture Victoria, AgriBio, Centre for AgriBioscience, Bundoora, VIC, Australia
Ruidong Xiang & Amanda Chamberlain
4. Genome Center, University of California, Davis, Davis, CA, USA
Ian Korf
5. USDA-ARS, Avian Disease and Oncology Laboratory, East Lansing, MI, USA
Hans H. Cheng
6. Department of Animal Science, Iowa State University, Ames, IA, USA
Chris K. Tuggle
7. Department of Animal Science, Michigan State University, East Lansing, MI, USA
Catherine Ernst
8. European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
Paul Flicek
9. Department of Molecular and Cellular Biology, University of California, David, Davis, CA, USA
Gerald Quon
Authors
1. Colin Kern
[ View author publications ](/search?author=Colin%20Kern)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Colin%20Kern)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Colin%20Kern%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
2. Ying Wang
[ View author publications ](/search?author=Ying%20Wang)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Ying%20Wang) [
Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Ying%20Wang%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
3. Xiaoqin Xu
[ View author publications ](/search?author=Xiaoqin%20Xu)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Xiaoqin%20Xu)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Xiaoqin%20Xu%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
4. Zhangyuan Pan
[ View author publications ](/search?author=Zhangyuan%20Pan)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Zhangyuan%20Pan)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Zhangyuan%20Pan%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
5. Michelle Halstead
[ View author publications ](/search?author=Michelle%20Halstead)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Michelle%20Halstead)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Michelle%20Halstead%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
6. Ganrea Chanthavixay
[ View author publications ](/search?author=Ganrea%20Chanthavixay)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Ganrea%20Chanthavixay)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Ganrea%20Chanthavixay%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
7. Perot Saelao
[ View author publications ](/search?author=Perot%20Saelao)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Perot%20Saelao)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Perot%20Saelao%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
8. Susan Waters
[ View author publications ](/search?author=Susan%20Waters)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Susan%20Waters)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Susan%20Waters%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
9. Ruidong Xiang
[ View author publications ](/search?author=Ruidong%20Xiang)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Ruidong%20Xiang)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Ruidong%20Xiang%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
10. Amanda Chamberlain
[ View author publications ](/search?author=Amanda%20Chamberlain)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Amanda%20Chamberlain)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Amanda%20Chamberlain%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
11. Ian Korf
[ View author publications ](/search?author=Ian%20Korf)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Ian%20Korf) [
Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Ian%20Korf%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
12. Mary E. Delany
[ View author publications ](/search?author=Mary%20E.%20Delany)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Mary%20E.%20Delany)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Mary%20E.%20Delany%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
13. Hans H. Cheng
[ View author publications ](/search?author=Hans%20H.%20Cheng)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Hans%20H.%20Cheng)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Hans%20H.%20Cheng%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
14. Juan F. Medrano
[ View author publications ](/search?author=Juan%20F.%20Medrano)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Juan%20F.%20Medrano)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Juan%20F.%20Medrano%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
15. Alison L. Van Eenennaam
[ View author publications ](/search?author=Alison%20L.%20Van%20Eenennaam)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Alison%20L.%20Van%20Eenennaam)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Alison%20L.%20Van%20Eenennaam%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
16. Chris K. Tuggle
[ View author publications ](/search?author=Chris%20K.%20Tuggle)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Chris%20K.%20Tuggle)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Chris%20K.%20Tuggle%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
17. Catherine Ernst
[ View author publications ](/search?author=Catherine%20Ernst)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Catherine%20Ernst)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Catherine%20Ernst%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
18. Paul Flicek
[ View author publications ](/search?author=Paul%20Flicek)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Paul%20Flicek)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Paul%20Flicek%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
19. Gerald Quon
[ View author publications ](/search?author=Gerald%20Quon)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Gerald%20Quon)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Gerald%20Quon%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
20. Pablo Ross
[ View author publications ](/search?author=Pablo%20Ross)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Pablo%20Ross)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Pablo%20Ross%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
21. Huaijun Zhou
[ View author publications ](/search?author=Huaijun%20Zhou)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Huaijun%20Zhou)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Huaijun%20Zhou%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
### Contributions
C.K. performed all data analysis and wrote the manuscript. Y.W., X.X., Z.P,
G.C., P.S., and S.W. worked on preparation and sequencing of ChIP-seq
libraries. M.H. prepared and sequenced ATAC-seq libraries and assisted in some
steps of analyzing the ATAC-seq data. R.X. and A.C. contributed the GWAS SNPs
from dairy cattle. H.H.C. and C.E. provided experimental animals. I.K.,
M.E.D., H.H.C., J.F.M., A.L.V.E., C.K.T., C.E., P.F., G.Q., P.R., and H.Z.
contributed significantly to the experimental design. P.R. and H.Z. supervised
the study. All authors provided feedback while drafting the manuscript and
approved the final version.
### Corresponding authors
Correspondence to [ Pablo Ross ](mailto:[email protected]) or [ Huaijun Zhou
](mailto:[email protected]) .
## Ethics declarations
### Competing interests
The authors declare no competing interests.
## Additional information
**Peer review information** _Nature Communications_ thanks Lingzhao Fang and
Wen Wang for their contribution to the peer review of this work. Peer reviewer
reports are available.
**Publisher’s note** Springer Nature remains neutral with regard to
jurisdictional claims in published maps and institutional affiliations.
## Supplementary information
### [ Supplementary Information ](https://static-
content.springer.com/esm/art%3A10.1038%2Fs41467-021-22100-8/MediaObjects/41467_2021_22100_MOESM1_ESM.pdf)
### [ Peer Review File ](https://static-
content.springer.com/esm/art%3A10.1038%2Fs41467-021-22100-8/MediaObjects/41467_2021_22100_MOESM2_ESM.pdf)
### [ Description of Additional Supplementary Files ](https://static-
content.springer.com/esm/art%3A10.1038%2Fs41467-021-22100-8/MediaObjects/41467_2021_22100_MOESM3_ESM.pdf)
### [ Supplementary Data 1 ](https://static-
content.springer.com/esm/art%3A10.1038%2Fs41467-021-22100-8/MediaObjects/41467_2021_22100_MOESM4_ESM.xlsx)
### [ Supplementary Data 2 ](https://static-
content.springer.com/esm/art%3A10.1038%2Fs41467-021-22100-8/MediaObjects/41467_2021_22100_MOESM5_ESM.xlsx)
### [ Supplementary Data 3 ](https://static-
content.springer.com/esm/art%3A10.1038%2Fs41467-021-22100-8/MediaObjects/41467_2021_22100_MOESM6_ESM.xlsx)
### [ Reporting Summary ](https://static-
content.springer.com/esm/art%3A10.1038%2Fs41467-021-22100-8/MediaObjects/41467_2021_22100_MOESM7_ESM.pdf)
## Source data
### [ Source Data ](https://static-
content.springer.com/esm/art%3A10.1038%2Fs41467-021-22100-8/MediaObjects/41467_2021_22100_MOESM8_ESM.xlsx)
## Rights and permissions
**Open Access** This article is licensed under a Creative Commons Attribution
4.0 International License, which permits use, sharing, adaptation,
distribution and reproduction in any medium or format, as long as you give
appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons license, and indicate if changes were made. The images or
other third party material in this article are included in the article’s
Creative Commons license, unless indicated otherwise in a credit line to the
material. If material is not included in the article’s Creative Commons
license and your intended use is not permitted by statutory regulation or
exceeds the permitted use, you will need to obtain permission directly from
the copyright holder. To view a copy of this license, visit [
http://creativecommons.org/licenses/by/4.0/
](http://creativecommons.org/licenses/by/4.0/) .
[ Reprints and permissions
](https://s100.copyright.com/AppDispatchServlet?title=Functional%20annotations%20of%20three%20domestic%20animal%20genomes%20provide%20vital%20resources%20for%20comparative%20and%20agricultural%20research&author=Colin%20Kern%20et%20al&contentID=10.1038%2Fs41467-021-22100-8©right=The%20Author%28s%29&publication=2041-1723&publicationDate=2021-03-23&publisherName=SpringerNature&orderBeanReset=true&oa=CC%20BY)
## About this article
[ 
](https://crossmark.crossref.org/dialog/?doi=10.1038/s41467-021-22100-8)
### Cite this article
Kern, C., Wang, Y., Xu, X. _et al._ Functional annotations of three domestic
animal genomes provide vital resources for comparative and agricultural
research. _Nat Commun_ **12** , 1821 (2021).
https://doi.org/10.1038/s41467-021-22100-8
[ Download citation ](https://citation-
needed.springer.com/v2/references/10.1038/s41467-021-22100-8?format=refman&flavour=citation)
* Received : 26 October 2020
* Accepted : 01 March 2021
* Published : 23 March 2021
* DOI : https://doi.org/10.1038/s41467-021-22100-8
### Share this article
Anyone you share the following link with will be able to read this content:
Get shareable link
Sorry, a shareable link is not currently available for this article.
Copy to clipboard
Provided by the Springer Nature SharedIt content-sharing initiative
## This article is cited by
* ### [ Genomic dissection of the correlation between milk yield and various health traits using functional and evolutionary information about imputed sequence variants of 34,497 German Holstein cows ](https://doi.org/10.1186/s12864-024-10115-6)
* Helen Schneider
* Ana-Marija Krizanac
* Jörn Bennewitz
_BMC Genomics_ (2024)
* ### [ Omics-based construction of regulatory variants can be applied to help decipher pig liver-related traits ](https://doi.org/10.1038/s42003-024-06050-7)
* Ziqi Ling
* Jing Li
* Lusheng Huang
_Communications Biology_ (2024)
* ### [ Establishment of a cloning-free CRISPR/Cas9 protocol to generate large deletions in the bovine MDBK cell line ](https://doi.org/10.1007/s13353-024-00846-3)
* Joanna Stojak
* Dominique Rocha
* Hiroaki Taniguchi
_Journal of Applied Genetics_ (2024)
* ### [ A genome-wide association study for loin depth and muscle pH in pigs from intensely selected purebred lines ](https://doi.org/10.1186/s12711-023-00815-0)
* Suzanne Desire
* Martin Johnsson
* Melissa K. Jungnickel
_Genetics Selection Evolution_ (2023)
* ### [ Genome-wide association analysis of heifer livability and early first calving in Holstein cattle ](https://doi.org/10.1186/s12864-023-09736-0)
* Yahui Gao
* Alexis Marceau
* Li Ma
_BMC Genomics_ (2023)
## Comments
By submitting a comment you agree to abide by our [ Terms ](/info/tandc.html)
and [ Community Guidelines ](/info/community-guidelines.html) . If you find
something abusive or that does not comply with our terms or guidelines please
flag it as inappropriate.
[ Download PDF ](/articles/s41467-021-22100-8.pdf)
Advertisement
[
](//pubads.g.doubleclick.net/gampad/jump?iu=/285/nature_communications/article&sz=300x250&c=1824618622&t=pos%3Dright%26type%3Darticle%26artid%3Ds41467-021-22100-8%26doi%3D10.1038/s41467-021-22100-8%26techmeta%3D15,22,23,45,90,91%26subjmeta%3D177,200,208,631,8%26kwrd%3DAgricultural+genetics,Epigenomics,Gene+regulation)
## Explore content
* [ Research articles ](/ncomms/research-articles)
* [ Reviews & Analysis ](/ncomms/reviews-and-analysis)
* [ News & Comment ](/ncomms/news-and-comment)
* [ Videos ](/ncomms/video)
* [ Collections ](/ncomms/collections)
* [ Subjects ](/ncomms/browse-subjects)
* [ Follow us on Facebook ](https://www.facebook.com/NatureCommunications)
* [ Follow us on Twitter ](https://twitter.com/NatureComms)
* [ Sign up for alerts ](https://www.nature.com/my-account/alerts/subscribe-journal?list-id=264)
* [ RSS feed ](https://www.nature.com/ncomms.rss)
## About the journal
* [ Aims & Scope ](/ncomms/aims)
* [ Editors ](/ncomms/editors)
* [ Journal Information ](/ncomms/journal-information)
* [ Open Access Fees and Funding ](/ncomms/open-access)
* [ Calls for Papers ](/ncomms/calls-for-papers)
* [ Editorial Values Statement ](/ncomms/editorial-values-statement)
* [ Journal Metrics ](/ncomms/journal-impact)
* [ Editors' Highlights ](/ncomms/editorshighlights)
* [ Contact ](/ncomms/contact)
* [ Editorial policies ](/ncomms/editorial-policies)
* [ Top Articles ](/ncomms/top-articles)
## Publish with us
* [ For authors ](/ncomms/submit)
* [ For Reviewers ](/ncomms/for-reviewers)
* [ Language editing services ](https://authorservices.springernature.com/go/sn/?utm_source=For+Authors&utm_medium=Website_Nature&utm_campaign=Platform+Experimentation+2022&utm_id=PE2022)
* [ Submit manuscript ](https://mts-ncomms.nature.com/)
## Search
Search articles by subject, keyword or author
Show results from All journals This journal
Search
[ Advanced search ](/search/advanced)
### Quick links
* [ Explore articles by subject ](/subjects)
* [ Find a job ](/naturecareers)
* [ Guide to authors ](/authors/index.html)
* [ Editorial policies ](/authors/editorial_policies/)
Nature Communications ( _Nat Commun_ ) ISSN 2041-1723 (online)
## nature.com sitemap
### About Nature Portfolio
* [ About us ](https://www.nature.com/npg_/company_info/index.html)
* [ Press releases ](https://www.nature.com/npg_/press_room/press_releases.html)
* [ Press office ](https://press.nature.com/)
* [ Contact us ](https://support.nature.com/support/home)
### Discover content
* [ Journals A-Z ](https://www.nature.com/siteindex)
* [ Articles by subject ](https://www.nature.com/subjects)
* [ protocols.io ](https://www.protocols.io/)
* [ Nature Index ](https://www.natureindex.com/)
### Publishing policies
* [ Nature portfolio policies ](https://www.nature.com/authors/editorial_policies)
* [ Open access ](https://www.nature.com/nature-research/open-access)
### Author & Researcher services
* [ Reprints & permissions ](https://www.nature.com/reprints)
* [ Research data ](https://www.springernature.com/gp/authors/research-data)
* [ Language editing ](https://authorservices.springernature.com/language-editing/)
* [ Scientific editing ](https://authorservices.springernature.com/scientific-editing/)
* [ Nature Masterclasses ](https://masterclasses.nature.com/)
* [ Research Solutions ](https://solutions.springernature.com/)
### Libraries & institutions
* [ Librarian service & tools ](https://www.springernature.com/gp/librarians/tools-services)
* [ Librarian portal ](https://www.springernature.com/gp/librarians/manage-your-account/librarianportal)
* [ Open research ](https://www.nature.com/openresearch/about-open-access/information-for-institutions)
* [ Recommend to library ](https://www.springernature.com/gp/librarians/recommend-to-your-library)
### Advertising & partnerships
* [ Advertising ](https://partnerships.nature.com/product/digital-advertising/)
* [ Partnerships & Services ](https://partnerships.nature.com/)
* [ Media kits ](https://partnerships.nature.com/media-kits/)
* [ Branded content ](https://partnerships.nature.com/product/branded-content-native-advertising/)
### Professional development
* [ Nature Careers ](https://www.nature.com/naturecareers/)
* [ Nature Conferences ](https://conferences.nature.com)
### Regional websites
* [ Nature Africa ](https://www.nature.com/natafrica)
* [ Nature China ](http://www.naturechina.com)
* [ Nature India ](https://www.nature.com/nindia)
* [ Nature Italy ](https://www.nature.com/natitaly)
* [ Nature Japan ](https://www.natureasia.com/ja-jp)
* [ Nature Middle East ](https://www.nature.com/nmiddleeast)
* [ Privacy Policy ](https://www.nature.com/info/privacy)
* [ Use of cookies ](https://www.nature.com/info/cookies)
* Your privacy choices/Manage cookies
* [ Legal notice ](https://www.nature.com/info/legal-notice)
* [ Accessibility statement ](https://www.nature.com/info/accessibility-statement)
* [ Terms & Conditions ](https://www.nature.com/info/terms-and-conditions)
* [ Your US state privacy rights ](https://www.springernature.com/ccpa)
[ 
](https://www.springernature.com/)
© 2024 Springer Nature Limited
Close banner Close
Sign up for the _Nature Briefing_ newsletter — what matters in science, free
to your inbox daily.
Email address
Sign up
I agree my information will be processed in accordance with the _Nature_ and
Springer Nature Limited [ Privacy Policy
](https://www.nature.com/info/privacy) .
Close banner Close
Get the most important science stories of the day, free in your inbox. [ Sign
up for Nature Briefing
](https://www.nature.com/briefing/signup/?brieferEntryPoint=MainBriefingBanner)
*[
DOI
]: Digital Object Identifier
*[
ISSN
]: International Standard Serial Number
| biology | 2491194 | https://sv.wikipedia.org/wiki/Chodsigoa%20salenskii | Chodsigoa salenskii | Chodsigoa salenskii är en däggdjursart som först beskrevs av Nikolai Feofanovich Kastschenko 1907. Chodsigoa salenskii ingår i släktet Chodsigoa och familjen näbbmöss. IUCN kategoriserar arten globalt som otillräckligt studerad. Inga underarter finns listade i Catalogue of Life.
Det upphittade exemplaret (holotyp) hade en kroppslängd (huvud och bål) av 78 mm, en svanslängd av 110 mm och 25 mm långa bakfötter. Annars har arten samma utseende som Chodsigoa smithii.
Den enda bekräftade förekomsten för arten är norra Sichuan i Kina. Enligt en omstridd studie från 2008 lever arten även i centrala Sichuan (Wolongs naturreservat) och i Guizhou. Inget är känt om habitat och levnadssätt.
Källor
Externa länkar
Näbbmöss
salenskii
Däggdjur i palearktiska regionen | swedish | 1.096375 |
smallest_genome/Genlisea_margaretae.txt |
Genlisea margaretae is a carnivorous species in the genus Genlisea (family Lentibulariaceae) native to areas of Madagascar, Tanzania, and Zambia. It has pale bundles of root-like organs up to about 20 cm long under ground that attract, trap, and digest protozoans. These organs are subterranean leaves, which lack chlorophyll. It had been known to possess the smallest known genome of any flowering plant as of 2006, but was later surpassed by the related species Genlisea tuberosa.
Characteristics[edit]
Genlisea margaretae is a perennial herb that forms small, compact rosettes composed of nearly linear leaves about 2 mm wide. Leaves are typically 5–50 mm in length, but most of that length, including the petiole, is hidden beneath the soil. It has no true roots and instead has highly modified subterranean leaves that act as the carnivorous trapping mechanism.
The inflorescences, which can grow to be 20–60 cm tall, emerge from the center of the rosette and produce mauve or violet-colored flowers. Each inflorescence can produce more than 10 flowers on a congested raceme. The upper part of the inflorescences is densely covered with glandular trichomes while the lower part has fewer trichomes and is often glabrous. Individual flowers have rounded upper lips on the corolla instead of being lobed and a relatively straight spur.
The genomes of several species in the genus Genlisea were studied in 2006 along with other members of the Lentibulariaceae family. According to the study, prior to its publication the smallest known angiosperm (flowering plant) genome was that of Arabidopsis thaliana at 157 Megabase pairs (Mbp). With a diploid chromosome number of around 40 (2n = ca. 40), G. margaretae held the distinction of having the smallest known angiosperm genome size at 63.4 Mbp, just 0.2 Mbp lower than that of Genlisea aurea. Further research in 2014 found that a related species, Genlisea tuberosa has a smaller genome size at around 61 Mbp. The smallest individual chromatids from mitotic anaphase are just 2.1 Mbp and therefore have a size smaller than some bacterial chromosomes, such as the approximate 4 Mbp of Escherichia coli. G. margaretae and G. aurea also both appear to be polyploid species with the unusual circumstances of having a high chromosome number with extremely small chromosomes. Other species in the genus Genlisea and the family Lentibulariaceae have much lower chromosome numbers and larger genome sizes, affirming that one characteristic of this botanic family is rapid molecular evolution. G. margaretae in particular may be helpful in research aimed at understanding the mechanisms behind genome downsizing.
At least one natural hybrid among the African species that involves G. margaretae has been described. Genlisea margaretae × glandulosissima is a product of G. margaretae and G. glandulosissima.
Distribution and habitat[edit]
Genlisea margaretae is one of the several Genlisea species native to Southeast Africa. It has been discovered in Tanzania and Zambia and is the only Genlisea species reported to exist in Madagascar. Its typical oligotrophous habitat includes inselbergs, ferricretes, and swamps.
Carnivory[edit]
Genlisea margaretae, like all Genlisea species, is a carnivorous plant that attracts, traps, kills, and digests prey, which are typically protozoans. Evidence of this behavior had been postulated ever since Charles Darwin's time and has mostly relied on circumstantial findings of the occasional dead aquatic invertebrate in the utricle (digestion chamber). In 1975, however, British botanist Yolande Heslop-Harrison discovered digestive enzyme activity in G. africana. Later, in 1998, Wilhelm Barthlott and his colleagues concluded through experimentation that Genlisea attracts prey chemotactically, traps them in the corkscrew "lobster pot" trap, digests them with enzymes produced by the plant, and then absorbs the nutrients. This study represented the first conclusive evidence that G. margaretae was carnivorous.
Cultivation[edit]
According to Barry Rice in his 2006 book on carnivorous plants, G. margaretae is an easy terrestrial species to grow. Leaf and trap cuttings can easily produce new plant clones. G. margaretae requires high humidity and medium to bright lighting conditions with soil composition similar to that of other carnivorous plants, especially the terrestrial Utricularia species. | biology | 4013475 | https://sv.wikipedia.org/wiki/Gasparinia%20elegans | Gasparinia elegans | Gasparinia elegans är en flockblommig växtart som beskrevs av Oljga N. Dubovik. Gasparinia elegans ingår i släktet Gasparinia och familjen flockblommiga växter. Inga underarter finns listade i Catalogue of Life.
Källor
Flockblommiga växter
elegans | swedish | 0.738131 |
smallest_genome/Genome_editing.txt | Genome editing, or genome engineering, or gene editing, is a type of genetic engineering in which DNA is inserted, deleted, modified or replaced in the genome of a living organism. Unlike early genetic engineering techniques that randomly inserts genetic material into a host genome, genome editing targets the insertions to site-specific locations. The basic mechanism involved in genetic manipulations through programmable nucleases is the recognition of target genomic loci and binding of effector DNA-binding domain (DBD), double-strand breaks (DSBs) in target DNA by the restriction endonucleases (FokI and Cas), and the repair of DSBs through homology-directed recombination (HDR) or non-homologous end joining (NHEJ).
Genome editing was pioneered in the 1990s, before the advent of the common current nuclease-based gene editing platforms but its use was limited by low efficiencies of editing. Genome editing with engineered nucleases, i.e. all three major classes of these enzymes—zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and engineered meganucleases—were selected by Nature Methods as the 2011 Method of the Year. The CRISPR-Cas system was selected by Science as 2015 Breakthrough of the Year.
As of 2015 four families of engineered nucleases were used: meganucleases, zinc finger nucleases (ZFNs), transcription activator-like effector-based nucleases (TALEN), and the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) system. Nine genome editors were available as of 2017.
In 2018, the common methods for such editing used engineered nucleases, or "molecular scissors". These nucleases create site-specific double-strand breaks (DSBs) at desired locations in the genome. The induced double-strand breaks are repaired through nonhomologous end-joining (NHEJ) or homologous recombination (HR), resulting in targeted mutations ('edits').
In May 2019, lawyers in China reported, in light of the purported creation by Chinese scientist He Jiankui of the first gene-edited humans (see Lulu and Nana controversy), the drafting of regulations that anyone manipulating the human genome by gene-editing techniques, like CRISPR, would be held responsible for any related adverse consequences. A cautionary perspective on the possible blind spots and risks of CRISPR and related biotechnologies has been recently discussed, focusing on the stochastic nature of cellular control processes.
The University of Edinburgh Roslin Institute engineered pigs resistant to a virus that causes porcine reproductive and respiratory syndrome, which costs US and European pig farmers $2.6 billion annually.
In February 2020, a US trial safely showed CRISPR gene editing on 3 cancer patients. In 2020 Sicilian Rouge High GABA, a tomato that makes more of an amino acid said to promote relaxation, was approved for sale in Japan.
In 2021, England (not the rest of the UK) planned to remove restrictions on gene-edited plants and animals, moving from European Union-compliant regulation to rules closer to those of the US and some other countries. An April 2021 European Commission report found "strong indications" that the current regulatory regime was not appropriate for gene editing Later in 2021, researchers announced a CRISPR alternative, labeled obligate mobile element–guided activity (OMEGA) proteins including IscB, IsrB and TnpB as endonucleases found in transposons, and guided by small ωRNAs.
Genetic engineering as method of introducing new genetic elements into organisms has been around since the 1970s. One drawback of this technology has been the random nature with which the DNA is inserted into the hosts genome, which can impair or alter other genes within the organism. Although, several methods have been discovered which target the inserted genes to specific sites within an organism genome. It has also enabled the editing of specific sequences within a genome as well as reduced off target effects. This could be used for research purposes, by targeting mutations to specific genes, and in gene therapy. By inserting a functional gene into an organism and targeting it to replace the defective one it could be possible to cure certain genetic diseases.
Early methods to target genes to certain sites within a genome of an organism (called gene targeting) relied on homologous recombination (HR). By creating DNA constructs that contain a template that matches the targeted genome sequence it is possible that the HR processes within the cell will insert the construct at the desired location. Using this method on embryonic stem cells led to the development of transgenic mice with targeted genes knocked out. It has also been possible to knock in genes or alter gene expression patterns. In recognition of their discovery of how homologous recombination can be used to introduce genetic modifications in mice through embryonic stem cells, Mario Capecchi, Martin Evans and Oliver Smithies were awarded the 2007 Nobel Prize for Physiology or Medicine.
If a vital gene is knocked out it can prove lethal to the organism. In order to study the function of these genes site specific recombinases (SSR) were used. The two most common types are the Cre-LoxP and Flp-FRT systems. Cre recombinase is an enzyme that removes DNA by homologous recombination between binding sequences known as Lox-P sites. The Flip-FRT system operates in a similar way, with the Flip recombinase recognising FRT sequences. By crossing an organism containing the recombinase sites flanking the gene of interest with an organism that express the SSR under control of tissue specific promoters, it is possible to knock out or switch on genes only in certain cells. These techniques were also used to remove marker genes from transgenic animals. Further modifications of these systems allowed researchers to induce recombination only under certain conditions, allowing genes to be knocked out or expressed at desired times or stages of development.
A common form of Genome editing relies on the concept of DNA double stranded break (DSB) repair mechanics. There are two major pathways that repair DSB; non-homologous end joining (NHEJ) and homology directed repair (HDR). NHEJ uses a variety of enzymes to directly join the DNA ends while the more accurate HDR uses a homologous sequence as a template for regeneration of missing DNA sequences at the break point. This can be exploited by creating a vector with the desired genetic elements within a sequence that is homologous to the flanking sequences of a DSB. This will result in the desired change being inserted at the site of the DSB. While HDR based gene editing is similar to the homologous recombination based gene targeting, the rate of recombination is increased by at least three orders of magnitude.
The key to genome editing is creating a DSB at a specific point within the genome. Commonly used restriction enzymes are effective at cutting DNA, but generally recognize and cut at multiple sites. To overcome this challenge and create site-specific DSB, three distinct classes of nucleases have been discovered and bioengineered to date. These are the Zinc finger nucleases (ZFNs), transcription-activator like effector nucleases (TALEN), meganucleases and the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) system.
Meganucleases, discovered in the late 1980s, are enzymes in the endonuclease family which are characterized by their capacity to recognize and cut large DNA sequences (from 14 to 40 base pairs). The most widespread and best known meganucleases are the proteins in the LAGLIDADG family, which owe their name to a conserved amino acid sequence.
Meganucleases, found commonly in microbial species, have the unique property of having very long recognition sequences (>14bp) thus making them naturally very specific. However, there is virtually no chance of finding the exact meganuclease required to act on a chosen specific DNA sequence. To overcome this challenge, mutagenesis and high throughput screening methods have been used to create meganuclease variants that recognize unique sequences. Others have been able to fuse various meganucleases and create hybrid enzymes that recognize a new sequence. Yet others have attempted to alter the DNA interacting aminoacids of the meganuclease to design sequence specific meganucelases in a method named rationally designed meganuclease. Another approach involves using computer models to try to predict as accurately as possible the activity of the modified meganucleases and the specificity of the recognized nucleic sequence.
A large bank containing several tens of thousands of protein units has been created. These units can be combined to obtain chimeric meganucleases that recognize the target site, thereby providing research and development tools that meet a wide range of needs (fundamental research, health, agriculture, industry, energy, etc.) These include the industrial-scale production of two meganucleases able to cleave the human XPC gene; mutations in this gene result in Xeroderma pigmentosum, a severe monogenic disorder that predisposes the patients to skin cancer and burns whenever their skin is exposed to UV rays.
Meganucleases have the benefit of causing less toxicity in cells than methods such as Zinc finger nuclease (ZFN), likely because of more stringent DNA sequence recognition; however, the construction of sequence-specific enzymes for all possible sequences is costly and time-consuming, as one is not benefiting from combinatorial possibilities that methods such as ZFNs and TALEN-based fusions utilize.
As opposed to meganucleases, the concept behind ZFNs and TALEN technology is based on a non-specific DNA cutting catalytic domain, which can then be linked to specific DNA sequence recognizing peptides such as zinc fingers and transcription activator-like effectors (TALEs). The first step to this was to find an endonuclease whose DNA recognition site and cleaving site were separate from each other, a situation that is not the most common among restriction enzymes. Once this enzyme was found, its cleaving portion could be separated which would be very non-specific as it would have no recognition ability. This portion could then be linked to sequence recognizing peptides that could lead to very high specificity.
Zinc finger motifs occur in several transcription factors. The zinc ion, found in 8% of all human proteins, plays an important role in the organization of their three-dimensional structure. In transcription factors, it is most often located at the protein-DNA interaction sites, where it stabilizes the motif. The C-terminal part of each finger is responsible for the specific recognition of the DNA sequence.
The recognized sequences are short, made up of around 3 base pairs, but by combining 6 to 8 zinc fingers whose recognition sites have been characterized, it is possible to obtain specific proteins for sequences of around 20 base pairs. It is therefore possible to control the expression of a specific gene. It has been demonstrated that this strategy can be used to promote a process of angiogenesis in animals. It is also possible to fuse a protein constructed in this way with the catalytic domain of an endonuclease in order to induce a targeted DNA break, and therefore to use these proteins as genome engineering tools.
The method generally adopted for this involves associating two DNA binding proteins – each containing 3 to 6 specifically chosen zinc fingers – with the catalytic domain of the FokI endonuclease which need to dimerize to cleave the double-strand DNA. The two proteins recognize two DNA sequences that are a few nucleotides apart. Linking the two zinc finger proteins to their respective sequences brings the two FokI domains closer together. FokI requires dimerization to have nuclease activity and this means the specificity increases dramatically as each nuclease partner would recognize a unique DNA sequence. To enhance this effect, FokI nucleases have been engineered that can only function as heterodimers.
Several approaches are used to design specific zinc finger nucleases for the chosen sequences. The most widespread involves combining zinc-finger units with known specificities (modular assembly). Various selection techniques, using bacteria, yeast or mammal cells have been developed to identify the combinations that offer the best specificity and the best cell tolerance. Although the direct genome-wide characterization of zinc finger nuclease activity has not been reported, an assay that measures the total number of double-strand DNA breaks in cells found that only one to two such breaks occur above background in cells treated with zinc finger nucleases with a 24 bp composite recognition site and obligate heterodimer FokI nuclease domains.
The heterodimer functioning nucleases would avoid the possibility of unwanted homodimer activity and thus increase specificity of the DSB. Although the nuclease portions of both ZFNs and TALEN constructs have similar properties, the difference between these engineered nucleases is in their DNA recognition peptide. ZFNs rely on Cys2-His2 zinc fingers and TALEN constructs on TALEs. Both of these DNA recognizing peptide domains have the characteristic that they are naturally found in combinations in their proteins. Cys2-His2 Zinc fingers typically happen in repeats that are 3 bp apart and are found in diverse combinations in a variety of nucleic acid interacting proteins such as transcription factors. Each finger of the Zinc finger domain is completely independent and the binding capacity of one finger is impacted by its neighbor. TALEs on the other hand are found in repeats with a one-to-one recognition ratio between the amino acids and the recognized nucleotide pairs. Because both zinc fingers and TALEs happen in repeated patterns, different combinations can be tried to create a wide variety of sequence specificities. Zinc fingers have been more established in these terms and approaches such as modular assembly (where Zinc fingers correlated with a triplet sequence are attached in a row to cover the required sequence), OPEN (low-stringency selection of peptide domains vs. triplet nucleotides followed by high-stringency selections of peptide combination vs. the final target in bacterial systems), and bacterial one-hybrid screening of zinc finger libraries among other methods have been used to make site specific nucleases.
Zinc finger nucleases are research and development tools that have already been used to modify a range of genomes, in particular by the laboratories in the Zinc Finger Consortium. The US company Sangamo BioSciences uses zinc finger nucleases to carry out research into the genetic engineering of stem cells and the modification of immune cells for therapeutic purposes. Modified T lymphocytes are currently undergoing phase I clinical trials to treat a type of brain tumor (glioblastoma) and in the fight against AIDS.
Transcription activator-like effector nucleases (TALENs) are specific DNA-binding proteins that feature an array of 33 or 34-amino acid repeats. TALENs are artificial restriction enzymes designed by fusing the DNA cutting domain of a nuclease to TALE domains, which can be tailored to specifically recognize a unique DNA sequence. These fusion proteins serve as readily targetable "DNA scissors" for gene editing applications that enable to perform targeted genome modifications such as sequence insertion, deletion, repair and replacement in living cells. The DNA binding domains, which can be designed to bind any desired DNA sequence, comes from TAL effectors, DNA-binding proteins excreted by plant pathogenic Xanthomanos app. TAL effectors consists of repeated domains, each of which contains a highly conserved sequence of 34 amino acids, and recognize a single DNA nucleotide within the target site. The nuclease can create double strand breaks at the target site that can be repaired by error-prone non-homologous end-joining (NHEJ), resulting in gene disruptions through the introduction of small insertions or deletions. Each repeat is conserved, with the exception of the so-called repeat variable di-residues (RVDs) at amino acid positions 12 and 13. The RVDs determine the DNA sequence to which the TALE will bind. This simple one-to-one correspondence between the TALE repeats and the corresponding DNA sequence makes the process of assembling repeat arrays to recognize novel DNA sequences straightforward. These TALEs can be fused to the catalytic domain from a DNA nuclease, FokI, to generate a transcription activator-like effector nuclease (TALEN). The resultant TALEN constructs combine specificity and activity, effectively generating engineered sequence-specific nucleases that bind and cleave DNA sequences only at pre-selected sites. The TALEN target recognition system is based on an easy-to-predict code. TAL nucleases are specific to their target due in part to the length of their 30+ base pairs binding site. TALEN can be performed within a 6 base pairs range of any single nucleotide in the entire genome.
TALEN constructs are used in a similar way to designed zinc finger nucleases, and have three advantages in targeted mutagenesis: (1) DNA binding specificity is higher, (2) off-target effects are lower, and (3) construction of DNA-binding domains is easier.
CRISPRs (Clustered Regularly Interspaced Short Palindromic Repeats) are genetic elements that bacteria use as a kind of acquired immunity to protect against viruses. They consist of short sequences that originate from viral genomes and have been incorporated into the bacterial genome. Cas (CRISPR associated proteins) process these sequences and cut matching viral DNA sequences. By introducing plasmids containing Cas genes and specifically constructed CRISPRs into eukaryotic cells, the eukaryotic genome can be cut at any desired position.
One of the earliest methods of efficiently editing nucleic acids employs nucleobase modifying enzymes directed by nucleic acid guide sequences was first described in the 1990s and has seen resurgence more recently. This method has the advantage that it does not require breaking the genomic DNA strands, and thus avoids the random insertion and deletions associated with DNA strand breakage. It is only appropriate for precise editing requiring single nucleotide changes and has found to be highly efficient for this type of editing.
ARCUT stands for artificial restriction DNA cutter, it is a technique developed by Komiyama. This method uses pseudo-complementary peptide nucleic acid (pcPNA), for identifying cleavage site within the chromosome. Once pcPNA specifies the site, excision is carried out by cerium (CE) and EDTA (chemical mixture), which performs the splicing function.
Meganucleases method of gene editing is the least efficient of the methods mentioned above. Due to the nature of its DNA-binding element and the cleaving element, it is limited to recognizing one potential target every 1,000 nucleotides. ZFN was developed to overcome the limitations of meganuclease. The number of possible targets ZFN can recognized was increased to one in every 140 nucleotides. However, both methods are unpredictable because of their DNA-binding elements affecting each other. As a result, high degrees of expertise and lengthy and costly validations processes are required.
TALE nucleases being the most precise and specific method yields a higher efficiency than the previous two methods. It achieves such efficiency because the DNA-binding element consists of an array of TALE subunits, each of them having the capability of recognizing a specific DNA nucleotide chain independent from others, resulting in a higher number of target sites with high precision. New TALE nucleases take about one week and a few hundred dollars to create, with specific expertise in molecular biology and protein engineering.
CRISPR nucleases have a slightly lower precision when compared to the TALE nucleases. This is caused by the need of having a specific nucleotide at one end in order to produce the guide RNA that CRISPR uses to repair the double-strand break it induces. It has been shown to be the quickest and cheapest method, only costing less than two hundred dollars and a few days of time. CRISPR also requires the least amount of expertise in molecular biology as the design lays in the guide RNA instead of the proteins. One major advantage that CRISPR has over the ZFN and TALEN methods is that it can be directed to target different DNA sequences using its ~80nt CRISPR sgRNAs, while both ZFN and TALEN methods required construction and testing of the proteins created for targeting each DNA sequence.
Because off-target activity of an active nuclease would have potentially dangerous consequences at the genetic and organismal levels, the precision of meganucleases, ZFNs, CRISPR, and TALEN-based fusions has been an active area of research. While variable figures have been reported, ZFNs tend to have more cytotoxicity than TALEN methods or RNA-guided nucleases, while TALEN and RNA-guided approaches tend to have the greatest efficiency and fewer off-target effects. Based on the maximum theoretical distance between DNA binding and nuclease activity, TALEN approaches result in the greatest precision.
The methods for scientists and researchers wanting to study genomic diversity and all possible associated phenotypes were very slow, expensive, and inefficient. Prior to this new revolution, researchers would have to do single-gene manipulations and tweak the genome one little section at a time, observe the phenotype, and start the process over with a different single-gene manipulation. Therefore, researchers at the Wyss Institute at Harvard University designed the MAGE, a powerful technology that improves the process of in vivo genome editing. It allows for quick and efficient manipulations of a genome, all happening in a machine small enough to put on top of a small kitchen table. Those mutations combine with the variation that naturally occurs during cell mitosis creating billions of cellular mutations.
Chemically combined, synthetic single-stranded DNA (ssDNA) and a pool of oligionucleotides are introduced at targeted areas of the cell thereby creating genetic modifications. The cyclical process involves transformation of ssDNA (by electroporation) followed by outgrowth, during which bacteriophage homologous recombination proteins mediate annealing of ssDNAs to their genomic targets. Experiments targeting selective phenotypic markers are screened and identified by plating the cells on differential medias. Each cycle ultimately takes 2.5 hours to process, with additional time required to grow isogenic cultures and characterize mutations. By iteratively introducing libraries of mutagenic ssDNAs targeting multiple sites, MAGE can generate combinatorial genetic diversity in a cell population. There can be up to 50 genome edits, from single nucleotide base pairs to whole genome or gene networks simultaneously with results in a matter of days.
MAGE experiments can be divided into three classes, characterized by varying degrees of scale and complexity: (i) many target sites, single genetic mutations; (ii) single target site, many genetic mutations; and (iii) many target sites, many genetic mutations. An example of class three was reflected in 2009, where Church and colleagues were able to program Escherichia coli to produce five times the normal amount of lycopene, an antioxidant normally found in tomato seeds and linked to anti-cancer properties. They applied MAGE to optimize the 1-deoxy-D-xylulose 5-phosphate (DXP) metabolic pathway in Escherichia coli to overproduce isoprenoid lycopene. It took them about 3 days and just over $1,000 in materials. The ease, speed, and cost efficiency in which MAGE can alter genomes can transform how industries approach the manufacturing and production of important compounds in the bioengineering, bioenergy, biomedical engineering, synthetic biology, pharmaceutical, agricultural, and chemical industries.
As of 2012 efficient genome editing had been developed for a wide range of experimental systems ranging from plants to animals, often beyond clinical interest, and was becoming a standard experimental strategy in research labs. The recent generation of rat, zebrafish, maize and tobacco ZFN-mediated mutants and the improvements in TALEN-based approaches testify to the significance of the methods, and the list is expanding rapidly. Genome editing with engineered nucleases will likely contribute to many fields of life sciences from studying gene functions in plants and animals to gene therapy in humans. For instance, the field of synthetic biology which aims to engineer cells and organisms to perform novel functions, is likely to benefit from the ability of engineered nuclease to add or remove genomic elements and therefore create complex systems. In addition, gene functions can be studied using stem cells with engineered nucleases.
Listed below are some specific tasks this method can carry out:
The combination of recent discoveries in genetic engineering, particularly gene editing and the latest improvement in bovine reproduction technologies (e.g. in vitro embryo culture) allows for genome editing directly in fertilised oocytes using synthetic highly specific endonucleases. RNA-guided endonucleases:clustered regularly interspaced short palindromic repeats associated Cas9 (CRISPR/Cas9) are a new tool, further increasing the range of methods available. In particular CRISPR/Cas9 engineered endonucleases allows the use of multiple guide RNAs for simultaneous Knockouts (KO) in one step by cytoplasmic direct injection (CDI) on mammalian zygotes.
Furthermore, gene editing can be applied to certain types of fish in aquaculture such as Atlantic salmon. Gene editing in fish is currently experimental, but the possibilities include growth, disease resistance, sterility, controlled reproduction, and colour. Selecting for these traits can allow for a more sustainable environment and better welfare for the fish.
AquAdvantage salmon is a genetically modified Atlantic salmon developed by AquaBounty Technologies. The growth hormone-regulating gene in the Atlantic salmon is replaced with the growth hormone-regulating gene from the Pacific Chinook salmon and a promoter sequence from the ocean pout
Thanks to the parallel development of single-cell transcriptomics, genome editing and new stem cell models we are now entering a scientifically exciting period where functional genetics is no longer restricted to animal models but can be performed directly in human samples. Single-cell gene expression analysis has resolved a transcriptional road-map of human development from which key candidate genes are being identified for functional studies. Using global transcriptomics data to guide experimentation, the CRISPR based genome editing tool has made it feasible to disrupt or remove key genes in order to elucidate function in a human setting.
Genome editing using Meganuclease, ZFNs, and TALEN provides a new strategy for genetic manipulation in plants and are likely to assist in the engineering of desired plant traits by modifying endogenous genes. For instance, site-specific gene addition in major crop species can be used for 'trait stacking' whereby several desired traits are physically linked to ensure their co-segregation during the breeding processes. Progress in such cases have been recently reported in Arabidopsis thaliana and Zea mays. In Arabidopsis thaliana, using ZFN-assisted gene targeting, two herbicide-resistant genes (tobacco acetolactate synthase SuRA and SuRB) were introduced to SuR loci with as high as 2% transformed cells with mutations. In Zea mays, disruption of the target locus was achieved by ZFN-induced DSBs and the resulting NHEJ. ZFN was also used to drive herbicide-tolerance gene expression cassette (PAT) into the targeted endogenous locus IPK1 in this case. Such genome modification observed in the regenerated plants has been shown to be inheritable and was transmitted to the next generation. A potentially successful example of the application of genome editing techniques in crop improvement can be found in banana, where scientists used CRISPR/Cas9 editing to inactivate the endogenous banana streak virus in the B genome of banana (Musa spp.) to overcome a major challenge in banana breeding.
In addition, TALEN-based genome engineering has been extensively tested and optimized for use in plants. TALEN fusions have also been used by a U.S. food ingredient company, Calyxt, to improve the quality of soybean oil products and to increase the storage potential of potatoes
Several optimizations need to be made in order to improve editing plant genomes using ZFN-mediated targeting. There is a need for reliable design and subsequent test of the nucleases, the absence of toxicity of the nucleases, the appropriate choice of the plant tissue for targeting, the routes of induction of enzyme activity, the lack of off-target mutagenesis, and a reliable detection of mutated cases.
A common delivery method for CRISPR/Cas9 in plants is Agrobacterium-based transformation. T-DNA is introduced directly into the plant genome by a T4SS mechanism. Cas9 and gRNA-based expression cassettes are turned into Ti plasmids, which are transformed in Agrobacterium for plant application. To improve Cas9 delivery in live plants, viruses are being used more effective transgene delivery.
The ideal gene therapy practice is that which replaces the defective gene with a normal allele at its natural location. This is advantageous over a virally delivered gene as there is no need to include the full coding sequences and regulatory sequences when only a small proportions of the gene needs to be altered as is often the case. The expression of the partially replaced genes is also more consistent with normal cell biology than full genes that are carried by viral vectors.
The first clinical use of TALEN-based genome editing was in the treatment of CD19+ acute lymphoblastic leukemia in an 11-month old child in 2015. Modified donor T cells were engineered to attack the leukemia cells, to be resistant to Alemtuzumab, and to evade detection by the host immune system after introduction.
Extensive research has been done in cells and animals using CRISPR-Cas9 to attempt to correct genetic mutations which cause genetic diseases such as Down syndrome, spina bifida, anencephaly, and Turner and Klinefelter syndromes.
In February 2019, medical scientists working with Sangamo Therapeutics, headquartered in Richmond, California, announced the first ever "in body" human gene editing therapy to permanently alter DNA - in a patient with Hunter syndrome. Clinical trials by Sangamo involving gene editing using Zinc Finger Nuclease (ZFN) are ongoing.
Researchers have used CRISPR-Cas9 gene drives to modify genes associated with sterility in A. gambiae, the vector for malaria. This technique has further implications in eradicating other vector borne diseases such as yellow fever, dengue, and Zika.
The CRISPR-Cas9 system can be programmed to modulate the population of any bacterial species by targeting clinical genotypes or epidemiological isolates. It can selectively enable the beneficial bacterial species over the harmful ones by eliminating pathogen, which gives it an advantage over broad-spectrum antibiotics.
Antiviral applications for therapies targeting human viruses such as HIV, herpes, and hepatitis B virus are under research. CRISPR can be used to target the virus or the host to disrupt genes encoding the virus cell-surface receptor proteins. In November 2018, He Jiankui announced that he had edited two human embryos, to attempt to disable the gene for CCR5, which codes for a receptor that HIV uses to enter cells. He said that twin girls, Lulu and Nana, had been born a few weeks earlier. He said that the girls still carried functional copies of CCR5 along with disabled CCR5 (mosaicism) and were still vulnerable to HIV. The work was widely condemned as unethical, dangerous, and premature.
In January 2019, scientists in China reported the creation of five identical cloned gene-edited monkeys, using the same cloning technique that was used with Zhong Zhong and Hua Hua – the first ever cloned monkeys - and Dolly the sheep, and the same gene-editing Crispr-Cas9 technique allegedly used by He Jiankui in creating the first ever gene-modified human babies Lulu and Nana. The monkey clones were made in order to study several medical diseases.
In the future, an important goal of research into genome editing with engineered nucleases must be the improvement of the safety and specificity of the nucleases action. For example, improving the ability to detect off-target events can improve our ability to learn about ways of preventing them. In addition, zinc-fingers used in ZFNs are seldom completely specific, and some may cause a toxic reaction. However, the toxicity has been reported to be reduced by modifications done on the cleavage domain of the ZFN.
In addition, research by Dana Carroll into modifying the genome with engineered nucleases has shown the need for better understanding of the basic recombination and repair machinery of DNA. In the future, a possible method to identify secondary targets would be to capture broken ends from cells expressing the ZFNs and to sequence the flanking DNA using high-throughput sequencing.
Because of the ease of use and cost-efficiency of CRISPR, extensive research is currently being done on it. There are now more publications on CRISPR than ZFN and TALEN despite how recent the discovery of CRISPR is. Both CRISPR and TALEN are favored to be the choices to be implemented in large-scale productions due to their precision and efficiency.
Genome editing occurs also as a natural process without artificial genetic engineering. The agents that are competent to edit genetic codes are viruses or subviral RNA-agents.
Although GEEN has higher efficiency than many other methods in reverse genetics, it is still not highly efficient; in many cases less than half of the treated populations obtain the desired changes. For example, when one is planning to use the cell's NHEJ to create a mutation, the cell's HDR systems will also be at work correcting the DSB with lower mutational rates.
Traditionally, mice have been the most common choice for researchers as a host of a disease model. CRISPR can help bridge the gap between this model and human clinical trials by creating transgenic disease models in larger animals such as pigs, dogs, and non-human primates. Using the CRISPR-Cas9 system, the programmed Cas9 protein and the sgRNA can be directly introduced into fertilized zygotes to achieve the desired gene modifications when creating transgenic models in rodents. This allows bypassing of the usual cell targeting stage in generating transgenic lines, and as a result, it reduces generation time by 90%.
One potential that CRISPR brings with its effectiveness is the application of xenotransplantation. In previous research trials, CRISPR demonstrated the ability to target and eliminate endogenous retroviruses, which reduces the risk of transmitting diseases and reduces immune barriers. Eliminating these problems improves donor organ function, which brings this application closer to a reality.
In plants, genome editing is seen as a viable solution to the conservation of biodiversity. Gene drive are a potential tool to alter the reproductive rate of invasive species, although there are significant associated risks.
Many transhumanists see genome editing as a potential tool for human enhancement. Australian biologist and Professor of Genetics David Andrew Sinclair notes that "the new technologies with genome editing will allow it to be used on individuals (...) to have (...) healthier children" – designer babies. According to a September 2016 report by the Nuffield Council on Bioethics in the future it may be possible to enhance people with genes from other organisms or wholly synthetic genes to for example improve night vision and sense of smell. George Church has compiled a list of potential genetic modifications for possibly advantageous traits such as less need for sleep, cognition-related changes that protect against Alzheimer's disease, disease resistances and enhanced learning abilities along with some of the associated studies and potential negative effects.
The American National Academy of Sciences and National Academy of Medicine issued a report in February 2017 giving qualified support to human genome editing. They recommended that clinical trials for genome editing might one day be permitted once answers have been found to safety and efficiency problems "but only for serious conditions under stringent oversight."
In the 2016 Worldwide Threat Assessment of the US Intelligence Community statement United States Director of National Intelligence, James R. Clapper, named genome editing as a potential weapon of mass destruction, stating that genome editing conducted by countries with regulatory or ethical standards "different from Western countries" probably increases the risk of the creation of harmful biological agents or products. According to the statement the broad distribution, low cost, and accelerated pace of development of this technology, its deliberate or unintentional misuse might lead to far-reaching economic and national security implications. For instance technologies such as CRISPR could be used to make "killer mosquitoes" that cause plagues that wipe out staple crops.
According to a September 2016 report by the Nuffield Council on Bioethics, the simplicity and low cost of tools to edit the genetic code will allow amateurs – or "biohackers" – to perform their own experiments, posing a potential risk from the release of genetically modified bugs. The review also found that the risks and benefits of modifying a person's genome – and having those changes pass on to future generations – are so complex that they demand urgent ethical scrutiny. Such modifications might have unintended consequences which could harm not only the child, but also their future children, as the altered gene would be in their sperm or eggs. In 2001 Australian researchers Ronald Jackson and Ian Ramshaw were criticized for publishing a paper in the Journal of Virology that explored the potential control of mice, a major pest in Australia, by infecting them with an altered mousepox virus that would cause infertility as the provided sensitive information could lead to the manufacture of biological weapons by potential bioterrorists who might use the knowledge to create vaccine resistant strains of other pox viruses, such as smallpox, that could affect humans. Furthermore, there are additional concerns about the ecological risks of releasing gene drives into wild populations.
In 2007, the Nobel Prize for Physiology or Medicine was awarded to Mario Capecchi, Martin Evans and Oliver Smithies "for their discoveries of principles for introducing specific gene modifications in mice by the use of embryonic stem cells."
In 2020, the Nobel Prize in Chemistry was awarded to Emmanuelle Charpentier and Jennifer Doudna for "the development of a method for genome editing".
"WHO launches global registry on human genome editing." PharmaBiz, 31 Aug. 2019. Gale General OneFile, Accessed 27 Apr. 2020.
History[edit]
Genome editing was pioneered in the 1990s, before the advent of the common current nuclease-based gene editing platforms but its use was limited by low efficiencies of editing. Genome editing with engineered nucleases, i.e. all three major classes of these enzymes—zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs) and engineered meganucleases—were selected by Nature Methods as the 2011 Method of the Year. The CRISPR-Cas system was selected by Science as 2015 Breakthrough of the Year.
As of 2015 four families of engineered nucleases were used: meganucleases, zinc finger nucleases (ZFNs), transcription activator-like effector-based nucleases (TALEN), and the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) system. Nine genome editors were available as of 2017.
In 2018, the common methods for such editing used engineered nucleases, or "molecular scissors". These nucleases create site-specific double-strand breaks (DSBs) at desired locations in the genome. The induced double-strand breaks are repaired through nonhomologous end-joining (NHEJ) or homologous recombination (HR), resulting in targeted mutations ('edits').
In May 2019, lawyers in China reported, in light of the purported creation by Chinese scientist He Jiankui of the first gene-edited humans (see Lulu and Nana controversy), the drafting of regulations that anyone manipulating the human genome by gene-editing techniques, like CRISPR, would be held responsible for any related adverse consequences. A cautionary perspective on the possible blind spots and risks of CRISPR and related biotechnologies has been recently discussed, focusing on the stochastic nature of cellular control processes.
The University of Edinburgh Roslin Institute engineered pigs resistant to a virus that causes porcine reproductive and respiratory syndrome, which costs US and European pig farmers $2.6 billion annually.
In February 2020, a US trial safely showed CRISPR gene editing on 3 cancer patients. In 2020 Sicilian Rouge High GABA, a tomato that makes more of an amino acid said to promote relaxation, was approved for sale in Japan.
In 2021, England (not the rest of the UK) planned to remove restrictions on gene-edited plants and animals, moving from European Union-compliant regulation to rules closer to those of the US and some other countries. An April 2021 European Commission report found "strong indications" that the current regulatory regime was not appropriate for gene editing Later in 2021, researchers announced a CRISPR alternative, labeled obligate mobile element–guided activity (OMEGA) proteins including IscB, IsrB and TnpB as endonucleases found in transposons, and guided by small ωRNAs.
Background[edit]
Genetic engineering as method of introducing new genetic elements into organisms has been around since the 1970s. One drawback of this technology has been the random nature with which the DNA is inserted into the hosts genome, which can impair or alter other genes within the organism. Although, several methods have been discovered which target the inserted genes to specific sites within an organism genome. It has also enabled the editing of specific sequences within a genome as well as reduced off target effects. This could be used for research purposes, by targeting mutations to specific genes, and in gene therapy. By inserting a functional gene into an organism and targeting it to replace the defective one it could be possible to cure certain genetic diseases.
Gene targeting[edit]
Homologous recombination[edit]
Early methods to target genes to certain sites within a genome of an organism (called gene targeting) relied on homologous recombination (HR). By creating DNA constructs that contain a template that matches the targeted genome sequence it is possible that the HR processes within the cell will insert the construct at the desired location. Using this method on embryonic stem cells led to the development of transgenic mice with targeted genes knocked out. It has also been possible to knock in genes or alter gene expression patterns. In recognition of their discovery of how homologous recombination can be used to introduce genetic modifications in mice through embryonic stem cells, Mario Capecchi, Martin Evans and Oliver Smithies were awarded the 2007 Nobel Prize for Physiology or Medicine.
Conditional targeting[edit]
If a vital gene is knocked out it can prove lethal to the organism. In order to study the function of these genes site specific recombinases (SSR) were used. The two most common types are the Cre-LoxP and Flp-FRT systems. Cre recombinase is an enzyme that removes DNA by homologous recombination between binding sequences known as Lox-P sites. The Flip-FRT system operates in a similar way, with the Flip recombinase recognising FRT sequences. By crossing an organism containing the recombinase sites flanking the gene of interest with an organism that express the SSR under control of tissue specific promoters, it is possible to knock out or switch on genes only in certain cells. These techniques were also used to remove marker genes from transgenic animals. Further modifications of these systems allowed researchers to induce recombination only under certain conditions, allowing genes to be knocked out or expressed at desired times or stages of development.
Process[edit]
Double strand break repair[edit]
dsDNA-break repair pathways and genome editing using CRISPR-Cas nucleases
A common form of Genome editing relies on the concept of DNA double stranded break (DSB) repair mechanics. There are two major pathways that repair DSB; non-homologous end joining (NHEJ) and homology directed repair (HDR). NHEJ uses a variety of enzymes to directly join the DNA ends while the more accurate HDR uses a homologous sequence as a template for regeneration of missing DNA sequences at the break point. This can be exploited by creating a vector with the desired genetic elements within a sequence that is homologous to the flanking sequences of a DSB. This will result in the desired change being inserted at the site of the DSB. While HDR based gene editing is similar to the homologous recombination based gene targeting, the rate of recombination is increased by at least three orders of magnitude.
Engineered nucleases[edit]
Groups of engineered nucleases. Matching colors signify DNA recognition patterns
The key to genome editing is creating a DSB at a specific point within the genome. Commonly used restriction enzymes are effective at cutting DNA, but generally recognize and cut at multiple sites. To overcome this challenge and create site-specific DSB, three distinct classes of nucleases have been discovered and bioengineered to date. These are the Zinc finger nucleases (ZFNs), transcription-activator like effector nucleases (TALEN), meganucleases and the clustered regularly interspaced short palindromic repeats (CRISPR/Cas9) system.
Meganucleases[edit]
Meganucleases, discovered in the late 1980s, are enzymes in the endonuclease family which are characterized by their capacity to recognize and cut large DNA sequences (from 14 to 40 base pairs). The most widespread and best known meganucleases are the proteins in the LAGLIDADG family, which owe their name to a conserved amino acid sequence.
Meganucleases, found commonly in microbial species, have the unique property of having very long recognition sequences (>14bp) thus making them naturally very specific. However, there is virtually no chance of finding the exact meganuclease required to act on a chosen specific DNA sequence. To overcome this challenge, mutagenesis and high throughput screening methods have been used to create meganuclease variants that recognize unique sequences. Others have been able to fuse various meganucleases and create hybrid enzymes that recognize a new sequence. Yet others have attempted to alter the DNA interacting aminoacids of the meganuclease to design sequence specific meganucelases in a method named rationally designed meganuclease. Another approach involves using computer models to try to predict as accurately as possible the activity of the modified meganucleases and the specificity of the recognized nucleic sequence.
A large bank containing several tens of thousands of protein units has been created. These units can be combined to obtain chimeric meganucleases that recognize the target site, thereby providing research and development tools that meet a wide range of needs (fundamental research, health, agriculture, industry, energy, etc.) These include the industrial-scale production of two meganucleases able to cleave the human XPC gene; mutations in this gene result in Xeroderma pigmentosum, a severe monogenic disorder that predisposes the patients to skin cancer and burns whenever their skin is exposed to UV rays.
Meganucleases have the benefit of causing less toxicity in cells than methods such as Zinc finger nuclease (ZFN), likely because of more stringent DNA sequence recognition; however, the construction of sequence-specific enzymes for all possible sequences is costly and time-consuming, as one is not benefiting from combinatorial possibilities that methods such as ZFNs and TALEN-based fusions utilize.
Zinc finger nucleases[edit]
As opposed to meganucleases, the concept behind ZFNs and TALEN technology is based on a non-specific DNA cutting catalytic domain, which can then be linked to specific DNA sequence recognizing peptides such as zinc fingers and transcription activator-like effectors (TALEs). The first step to this was to find an endonuclease whose DNA recognition site and cleaving site were separate from each other, a situation that is not the most common among restriction enzymes. Once this enzyme was found, its cleaving portion could be separated which would be very non-specific as it would have no recognition ability. This portion could then be linked to sequence recognizing peptides that could lead to very high specificity.
Zinc finger motifs occur in several transcription factors. The zinc ion, found in 8% of all human proteins, plays an important role in the organization of their three-dimensional structure. In transcription factors, it is most often located at the protein-DNA interaction sites, where it stabilizes the motif. The C-terminal part of each finger is responsible for the specific recognition of the DNA sequence.
The recognized sequences are short, made up of around 3 base pairs, but by combining 6 to 8 zinc fingers whose recognition sites have been characterized, it is possible to obtain specific proteins for sequences of around 20 base pairs. It is therefore possible to control the expression of a specific gene. It has been demonstrated that this strategy can be used to promote a process of angiogenesis in animals. It is also possible to fuse a protein constructed in this way with the catalytic domain of an endonuclease in order to induce a targeted DNA break, and therefore to use these proteins as genome engineering tools.
The method generally adopted for this involves associating two DNA binding proteins – each containing 3 to 6 specifically chosen zinc fingers – with the catalytic domain of the FokI endonuclease which need to dimerize to cleave the double-strand DNA. The two proteins recognize two DNA sequences that are a few nucleotides apart. Linking the two zinc finger proteins to their respective sequences brings the two FokI domains closer together. FokI requires dimerization to have nuclease activity and this means the specificity increases dramatically as each nuclease partner would recognize a unique DNA sequence. To enhance this effect, FokI nucleases have been engineered that can only function as heterodimers.
Several approaches are used to design specific zinc finger nucleases for the chosen sequences. The most widespread involves combining zinc-finger units with known specificities (modular assembly). Various selection techniques, using bacteria, yeast or mammal cells have been developed to identify the combinations that offer the best specificity and the best cell tolerance. Although the direct genome-wide characterization of zinc finger nuclease activity has not been reported, an assay that measures the total number of double-strand DNA breaks in cells found that only one to two such breaks occur above background in cells treated with zinc finger nucleases with a 24 bp composite recognition site and obligate heterodimer FokI nuclease domains.
The heterodimer functioning nucleases would avoid the possibility of unwanted homodimer activity and thus increase specificity of the DSB. Although the nuclease portions of both ZFNs and TALEN constructs have similar properties, the difference between these engineered nucleases is in their DNA recognition peptide. ZFNs rely on Cys2-His2 zinc fingers and TALEN constructs on TALEs. Both of these DNA recognizing peptide domains have the characteristic that they are naturally found in combinations in their proteins. Cys2-His2 Zinc fingers typically happen in repeats that are 3 bp apart and are found in diverse combinations in a variety of nucleic acid interacting proteins such as transcription factors. Each finger of the Zinc finger domain is completely independent and the binding capacity of one finger is impacted by its neighbor. TALEs on the other hand are found in repeats with a one-to-one recognition ratio between the amino acids and the recognized nucleotide pairs. Because both zinc fingers and TALEs happen in repeated patterns, different combinations can be tried to create a wide variety of sequence specificities. Zinc fingers have been more established in these terms and approaches such as modular assembly (where Zinc fingers correlated with a triplet sequence are attached in a row to cover the required sequence), OPEN (low-stringency selection of peptide domains vs. triplet nucleotides followed by high-stringency selections of peptide combination vs. the final target in bacterial systems), and bacterial one-hybrid screening of zinc finger libraries among other methods have been used to make site specific nucleases.
Zinc finger nucleases are research and development tools that have already been used to modify a range of genomes, in particular by the laboratories in the Zinc Finger Consortium. The US company Sangamo BioSciences uses zinc finger nucleases to carry out research into the genetic engineering of stem cells and the modification of immune cells for therapeutic purposes. Modified T lymphocytes are currently undergoing phase I clinical trials to treat a type of brain tumor (glioblastoma) and in the fight against AIDS.
TALEN[edit]
General overview of the TALEN process
Transcription activator-like effector nucleases (TALENs) are specific DNA-binding proteins that feature an array of 33 or 34-amino acid repeats. TALENs are artificial restriction enzymes designed by fusing the DNA cutting domain of a nuclease to TALE domains, which can be tailored to specifically recognize a unique DNA sequence. These fusion proteins serve as readily targetable "DNA scissors" for gene editing applications that enable to perform targeted genome modifications such as sequence insertion, deletion, repair and replacement in living cells. The DNA binding domains, which can be designed to bind any desired DNA sequence, comes from TAL effectors, DNA-binding proteins excreted by plant pathogenic Xanthomanos app. TAL effectors consists of repeated domains, each of which contains a highly conserved sequence of 34 amino acids, and recognize a single DNA nucleotide within the target site. The nuclease can create double strand breaks at the target site that can be repaired by error-prone non-homologous end-joining (NHEJ), resulting in gene disruptions through the introduction of small insertions or deletions. Each repeat is conserved, with the exception of the so-called repeat variable di-residues (RVDs) at amino acid positions 12 and 13. The RVDs determine the DNA sequence to which the TALE will bind. This simple one-to-one correspondence between the TALE repeats and the corresponding DNA sequence makes the process of assembling repeat arrays to recognize novel DNA sequences straightforward. These TALEs can be fused to the catalytic domain from a DNA nuclease, FokI, to generate a transcription activator-like effector nuclease (TALEN). The resultant TALEN constructs combine specificity and activity, effectively generating engineered sequence-specific nucleases that bind and cleave DNA sequences only at pre-selected sites. The TALEN target recognition system is based on an easy-to-predict code. TAL nucleases are specific to their target due in part to the length of their 30+ base pairs binding site. TALEN can be performed within a 6 base pairs range of any single nucleotide in the entire genome.
TALEN constructs are used in a similar way to designed zinc finger nucleases, and have three advantages in targeted mutagenesis: (1) DNA binding specificity is higher, (2) off-target effects are lower, and (3) construction of DNA-binding domains is easier.
CRISPR[edit]
Main article: CRISPR gene editing
CRISPRs (Clustered Regularly Interspaced Short Palindromic Repeats) are genetic elements that bacteria use as a kind of acquired immunity to protect against viruses. They consist of short sequences that originate from viral genomes and have been incorporated into the bacterial genome. Cas (CRISPR associated proteins) process these sequences and cut matching viral DNA sequences. By introducing plasmids containing Cas genes and specifically constructed CRISPRs into eukaryotic cells, the eukaryotic genome can be cut at any desired position.
Editing by nucleobase modification (Base editing)[edit]
One of the earliest methods of efficiently editing nucleic acids employs nucleobase modifying enzymes directed by nucleic acid guide sequences was first described in the 1990s and has seen resurgence more recently. This method has the advantage that it does not require breaking the genomic DNA strands, and thus avoids the random insertion and deletions associated with DNA strand breakage. It is only appropriate for precise editing requiring single nucleotide changes and has found to be highly efficient for this type of editing.
ARCUT[edit]
ARCUT stands for artificial restriction DNA cutter, it is a technique developed by Komiyama. This method uses pseudo-complementary peptide nucleic acid (pcPNA), for identifying cleavage site within the chromosome. Once pcPNA specifies the site, excision is carried out by cerium (CE) and EDTA (chemical mixture), which performs the splicing function.
Precision and efficiency of engineered nucleases[edit]
Meganucleases method of gene editing is the least efficient of the methods mentioned above. Due to the nature of its DNA-binding element and the cleaving element, it is limited to recognizing one potential target every 1,000 nucleotides. ZFN was developed to overcome the limitations of meganuclease. The number of possible targets ZFN can recognized was increased to one in every 140 nucleotides. However, both methods are unpredictable because of their DNA-binding elements affecting each other. As a result, high degrees of expertise and lengthy and costly validations processes are required.
TALE nucleases being the most precise and specific method yields a higher efficiency than the previous two methods. It achieves such efficiency because the DNA-binding element consists of an array of TALE subunits, each of them having the capability of recognizing a specific DNA nucleotide chain independent from others, resulting in a higher number of target sites with high precision. New TALE nucleases take about one week and a few hundred dollars to create, with specific expertise in molecular biology and protein engineering.
CRISPR nucleases have a slightly lower precision when compared to the TALE nucleases. This is caused by the need of having a specific nucleotide at one end in order to produce the guide RNA that CRISPR uses to repair the double-strand break it induces. It has been shown to be the quickest and cheapest method, only costing less than two hundred dollars and a few days of time. CRISPR also requires the least amount of expertise in molecular biology as the design lays in the guide RNA instead of the proteins. One major advantage that CRISPR has over the ZFN and TALEN methods is that it can be directed to target different DNA sequences using its ~80nt CRISPR sgRNAs, while both ZFN and TALEN methods required construction and testing of the proteins created for targeting each DNA sequence.
Because off-target activity of an active nuclease would have potentially dangerous consequences at the genetic and organismal levels, the precision of meganucleases, ZFNs, CRISPR, and TALEN-based fusions has been an active area of research. While variable figures have been reported, ZFNs tend to have more cytotoxicity than TALEN methods or RNA-guided nucleases, while TALEN and RNA-guided approaches tend to have the greatest efficiency and fewer off-target effects. Based on the maximum theoretical distance between DNA binding and nuclease activity, TALEN approaches result in the greatest precision.
Multiplex Automated Genomic Engineering (MAGE)[edit]
Synthetic DNA is repeatedly introduced at multiple targeted areas of the chromosome and/or loci and then is replicated producing cells with/without mutations.
The methods for scientists and researchers wanting to study genomic diversity and all possible associated phenotypes were very slow, expensive, and inefficient. Prior to this new revolution, researchers would have to do single-gene manipulations and tweak the genome one little section at a time, observe the phenotype, and start the process over with a different single-gene manipulation. Therefore, researchers at the Wyss Institute at Harvard University designed the MAGE, a powerful technology that improves the process of in vivo genome editing. It allows for quick and efficient manipulations of a genome, all happening in a machine small enough to put on top of a small kitchen table. Those mutations combine with the variation that naturally occurs during cell mitosis creating billions of cellular mutations.
Chemically combined, synthetic single-stranded DNA (ssDNA) and a pool of oligionucleotides are introduced at targeted areas of the cell thereby creating genetic modifications. The cyclical process involves transformation of ssDNA (by electroporation) followed by outgrowth, during which bacteriophage homologous recombination proteins mediate annealing of ssDNAs to their genomic targets. Experiments targeting selective phenotypic markers are screened and identified by plating the cells on differential medias. Each cycle ultimately takes 2.5 hours to process, with additional time required to grow isogenic cultures and characterize mutations. By iteratively introducing libraries of mutagenic ssDNAs targeting multiple sites, MAGE can generate combinatorial genetic diversity in a cell population. There can be up to 50 genome edits, from single nucleotide base pairs to whole genome or gene networks simultaneously with results in a matter of days.
MAGE experiments can be divided into three classes, characterized by varying degrees of scale and complexity: (i) many target sites, single genetic mutations; (ii) single target site, many genetic mutations; and (iii) many target sites, many genetic mutations. An example of class three was reflected in 2009, where Church and colleagues were able to program Escherichia coli to produce five times the normal amount of lycopene, an antioxidant normally found in tomato seeds and linked to anti-cancer properties. They applied MAGE to optimize the 1-deoxy-D-xylulose 5-phosphate (DXP) metabolic pathway in Escherichia coli to overproduce isoprenoid lycopene. It took them about 3 days and just over $1,000 in materials. The ease, speed, and cost efficiency in which MAGE can alter genomes can transform how industries approach the manufacturing and production of important compounds in the bioengineering, bioenergy, biomedical engineering, synthetic biology, pharmaceutical, agricultural, and chemical industries.
Applications[edit]
Plants, animals and human genes that are successfully targeted using ZFN, which demonstrates the generality of this approach
As of 2012 efficient genome editing had been developed for a wide range of experimental systems ranging from plants to animals, often beyond clinical interest, and was becoming a standard experimental strategy in research labs. The recent generation of rat, zebrafish, maize and tobacco ZFN-mediated mutants and the improvements in TALEN-based approaches testify to the significance of the methods, and the list is expanding rapidly. Genome editing with engineered nucleases will likely contribute to many fields of life sciences from studying gene functions in plants and animals to gene therapy in humans. For instance, the field of synthetic biology which aims to engineer cells and organisms to perform novel functions, is likely to benefit from the ability of engineered nuclease to add or remove genomic elements and therefore create complex systems. In addition, gene functions can be studied using stem cells with engineered nucleases.
Listed below are some specific tasks this method can carry out:
Targeted gene mutation
Gene therapy
Creating chromosome rearrangement
Study gene function with stem cells
Transgenic animals
Endogenous gene labeling
Targeted transgene addition
Targeted gene modification in animals[edit]
The combination of recent discoveries in genetic engineering, particularly gene editing and the latest improvement in bovine reproduction technologies (e.g. in vitro embryo culture) allows for genome editing directly in fertilised oocytes using synthetic highly specific endonucleases. RNA-guided endonucleases:clustered regularly interspaced short palindromic repeats associated Cas9 (CRISPR/Cas9) are a new tool, further increasing the range of methods available. In particular CRISPR/Cas9 engineered endonucleases allows the use of multiple guide RNAs for simultaneous Knockouts (KO) in one step by cytoplasmic direct injection (CDI) on mammalian zygotes.
Furthermore, gene editing can be applied to certain types of fish in aquaculture such as Atlantic salmon. Gene editing in fish is currently experimental, but the possibilities include growth, disease resistance, sterility, controlled reproduction, and colour. Selecting for these traits can allow for a more sustainable environment and better welfare for the fish.
AquAdvantage salmon is a genetically modified Atlantic salmon developed by AquaBounty Technologies. The growth hormone-regulating gene in the Atlantic salmon is replaced with the growth hormone-regulating gene from the Pacific Chinook salmon and a promoter sequence from the ocean pout
Thanks to the parallel development of single-cell transcriptomics, genome editing and new stem cell models we are now entering a scientifically exciting period where functional genetics is no longer restricted to animal models but can be performed directly in human samples. Single-cell gene expression analysis has resolved a transcriptional road-map of human development from which key candidate genes are being identified for functional studies. Using global transcriptomics data to guide experimentation, the CRISPR based genome editing tool has made it feasible to disrupt or remove key genes in order to elucidate function in a human setting.
Targeted gene modification in plants[edit]
Overview of GEEN workflow and editing possibilities
Genome editing using Meganuclease, ZFNs, and TALEN provides a new strategy for genetic manipulation in plants and are likely to assist in the engineering of desired plant traits by modifying endogenous genes. For instance, site-specific gene addition in major crop species can be used for 'trait stacking' whereby several desired traits are physically linked to ensure their co-segregation during the breeding processes. Progress in such cases have been recently reported in Arabidopsis thaliana and Zea mays. In Arabidopsis thaliana, using ZFN-assisted gene targeting, two herbicide-resistant genes (tobacco acetolactate synthase SuRA and SuRB) were introduced to SuR loci with as high as 2% transformed cells with mutations. In Zea mays, disruption of the target locus was achieved by ZFN-induced DSBs and the resulting NHEJ. ZFN was also used to drive herbicide-tolerance gene expression cassette (PAT) into the targeted endogenous locus IPK1 in this case. Such genome modification observed in the regenerated plants has been shown to be inheritable and was transmitted to the next generation. A potentially successful example of the application of genome editing techniques in crop improvement can be found in banana, where scientists used CRISPR/Cas9 editing to inactivate the endogenous banana streak virus in the B genome of banana (Musa spp.) to overcome a major challenge in banana breeding.
In addition, TALEN-based genome engineering has been extensively tested and optimized for use in plants. TALEN fusions have also been used by a U.S. food ingredient company, Calyxt, to improve the quality of soybean oil products and to increase the storage potential of potatoes
Several optimizations need to be made in order to improve editing plant genomes using ZFN-mediated targeting. There is a need for reliable design and subsequent test of the nucleases, the absence of toxicity of the nucleases, the appropriate choice of the plant tissue for targeting, the routes of induction of enzyme activity, the lack of off-target mutagenesis, and a reliable detection of mutated cases.
A common delivery method for CRISPR/Cas9 in plants is Agrobacterium-based transformation. T-DNA is introduced directly into the plant genome by a T4SS mechanism. Cas9 and gRNA-based expression cassettes are turned into Ti plasmids, which are transformed in Agrobacterium for plant application. To improve Cas9 delivery in live plants, viruses are being used more effective transgene delivery.
Part of a series of articles onSynthetic biology
Synthetic biological circuits
Synthetic gene database
BioBrick
Registry of Standard Biological Parts
Genome editing
CRISPR
Gene therapy
Synthetic immunology
Artificial cells
Artificial gene synthesis
Synthetic genomics
Mycoplasma laboratorium
Protocell
Xenobiology
Nucleic acid analogue
Xeno nucleic acid
Unnatural base pair
Expanded genetic code
Mirror life
Other topics
Hazards
Open synthetic biology
Do-it-yourself biology
vte
Research[edit]
Gene therapy[edit]
The ideal gene therapy practice is that which replaces the defective gene with a normal allele at its natural location. This is advantageous over a virally delivered gene as there is no need to include the full coding sequences and regulatory sequences when only a small proportions of the gene needs to be altered as is often the case. The expression of the partially replaced genes is also more consistent with normal cell biology than full genes that are carried by viral vectors.
The first clinical use of TALEN-based genome editing was in the treatment of CD19+ acute lymphoblastic leukemia in an 11-month old child in 2015. Modified donor T cells were engineered to attack the leukemia cells, to be resistant to Alemtuzumab, and to evade detection by the host immune system after introduction.
Extensive research has been done in cells and animals using CRISPR-Cas9 to attempt to correct genetic mutations which cause genetic diseases such as Down syndrome, spina bifida, anencephaly, and Turner and Klinefelter syndromes.
In February 2019, medical scientists working with Sangamo Therapeutics, headquartered in Richmond, California, announced the first ever "in body" human gene editing therapy to permanently alter DNA - in a patient with Hunter syndrome. Clinical trials by Sangamo involving gene editing using Zinc Finger Nuclease (ZFN) are ongoing.
Eradicating diseases[edit]
Researchers have used CRISPR-Cas9 gene drives to modify genes associated with sterility in A. gambiae, the vector for malaria. This technique has further implications in eradicating other vector borne diseases such as yellow fever, dengue, and Zika.
The CRISPR-Cas9 system can be programmed to modulate the population of any bacterial species by targeting clinical genotypes or epidemiological isolates. It can selectively enable the beneficial bacterial species over the harmful ones by eliminating pathogen, which gives it an advantage over broad-spectrum antibiotics.
Antiviral applications for therapies targeting human viruses such as HIV, herpes, and hepatitis B virus are under research. CRISPR can be used to target the virus or the host to disrupt genes encoding the virus cell-surface receptor proteins. In November 2018, He Jiankui announced that he had edited two human embryos, to attempt to disable the gene for CCR5, which codes for a receptor that HIV uses to enter cells. He said that twin girls, Lulu and Nana, had been born a few weeks earlier. He said that the girls still carried functional copies of CCR5 along with disabled CCR5 (mosaicism) and were still vulnerable to HIV. The work was widely condemned as unethical, dangerous, and premature.
In January 2019, scientists in China reported the creation of five identical cloned gene-edited monkeys, using the same cloning technique that was used with Zhong Zhong and Hua Hua – the first ever cloned monkeys - and Dolly the sheep, and the same gene-editing Crispr-Cas9 technique allegedly used by He Jiankui in creating the first ever gene-modified human babies Lulu and Nana. The monkey clones were made in order to study several medical diseases.
Prospects and limitations[edit]
In the future, an important goal of research into genome editing with engineered nucleases must be the improvement of the safety and specificity of the nucleases action. For example, improving the ability to detect off-target events can improve our ability to learn about ways of preventing them. In addition, zinc-fingers used in ZFNs are seldom completely specific, and some may cause a toxic reaction. However, the toxicity has been reported to be reduced by modifications done on the cleavage domain of the ZFN.
In addition, research by Dana Carroll into modifying the genome with engineered nucleases has shown the need for better understanding of the basic recombination and repair machinery of DNA. In the future, a possible method to identify secondary targets would be to capture broken ends from cells expressing the ZFNs and to sequence the flanking DNA using high-throughput sequencing.
Because of the ease of use and cost-efficiency of CRISPR, extensive research is currently being done on it. There are now more publications on CRISPR than ZFN and TALEN despite how recent the discovery of CRISPR is. Both CRISPR and TALEN are favored to be the choices to be implemented in large-scale productions due to their precision and efficiency.
Genome editing occurs also as a natural process without artificial genetic engineering. The agents that are competent to edit genetic codes are viruses or subviral RNA-agents.
Although GEEN has higher efficiency than many other methods in reverse genetics, it is still not highly efficient; in many cases less than half of the treated populations obtain the desired changes. For example, when one is planning to use the cell's NHEJ to create a mutation, the cell's HDR systems will also be at work correcting the DSB with lower mutational rates.
Traditionally, mice have been the most common choice for researchers as a host of a disease model. CRISPR can help bridge the gap between this model and human clinical trials by creating transgenic disease models in larger animals such as pigs, dogs, and non-human primates. Using the CRISPR-Cas9 system, the programmed Cas9 protein and the sgRNA can be directly introduced into fertilized zygotes to achieve the desired gene modifications when creating transgenic models in rodents. This allows bypassing of the usual cell targeting stage in generating transgenic lines, and as a result, it reduces generation time by 90%.
One potential that CRISPR brings with its effectiveness is the application of xenotransplantation. In previous research trials, CRISPR demonstrated the ability to target and eliminate endogenous retroviruses, which reduces the risk of transmitting diseases and reduces immune barriers. Eliminating these problems improves donor organ function, which brings this application closer to a reality.
In plants, genome editing is seen as a viable solution to the conservation of biodiversity. Gene drive are a potential tool to alter the reproductive rate of invasive species, although there are significant associated risks.
Human enhancement[edit]
Many transhumanists see genome editing as a potential tool for human enhancement. Australian biologist and Professor of Genetics David Andrew Sinclair notes that "the new technologies with genome editing will allow it to be used on individuals (...) to have (...) healthier children" – designer babies. According to a September 2016 report by the Nuffield Council on Bioethics in the future it may be possible to enhance people with genes from other organisms or wholly synthetic genes to for example improve night vision and sense of smell. George Church has compiled a list of potential genetic modifications for possibly advantageous traits such as less need for sleep, cognition-related changes that protect against Alzheimer's disease, disease resistances and enhanced learning abilities along with some of the associated studies and potential negative effects.
The American National Academy of Sciences and National Academy of Medicine issued a report in February 2017 giving qualified support to human genome editing. They recommended that clinical trials for genome editing might one day be permitted once answers have been found to safety and efficiency problems "but only for serious conditions under stringent oversight."
Risks[edit]
In the 2016 Worldwide Threat Assessment of the US Intelligence Community statement United States Director of National Intelligence, James R. Clapper, named genome editing as a potential weapon of mass destruction, stating that genome editing conducted by countries with regulatory or ethical standards "different from Western countries" probably increases the risk of the creation of harmful biological agents or products. According to the statement the broad distribution, low cost, and accelerated pace of development of this technology, its deliberate or unintentional misuse might lead to far-reaching economic and national security implications. For instance technologies such as CRISPR could be used to make "killer mosquitoes" that cause plagues that wipe out staple crops.
According to a September 2016 report by the Nuffield Council on Bioethics, the simplicity and low cost of tools to edit the genetic code will allow amateurs – or "biohackers" – to perform their own experiments, posing a potential risk from the release of genetically modified bugs. The review also found that the risks and benefits of modifying a person's genome – and having those changes pass on to future generations – are so complex that they demand urgent ethical scrutiny. Such modifications might have unintended consequences which could harm not only the child, but also their future children, as the altered gene would be in their sperm or eggs. In 2001 Australian researchers Ronald Jackson and Ian Ramshaw were criticized for publishing a paper in the Journal of Virology that explored the potential control of mice, a major pest in Australia, by infecting them with an altered mousepox virus that would cause infertility as the provided sensitive information could lead to the manufacture of biological weapons by potential bioterrorists who might use the knowledge to create vaccine resistant strains of other pox viruses, such as smallpox, that could affect humans. Furthermore, there are additional concerns about the ecological risks of releasing gene drives into wild populations.
Nobel prize[edit]
In 2007, the Nobel Prize for Physiology or Medicine was awarded to Mario Capecchi, Martin Evans and Oliver Smithies "for their discoveries of principles for introducing specific gene modifications in mice by the use of embryonic stem cells."
In 2020, the Nobel Prize in Chemistry was awarded to Emmanuelle Charpentier and Jennifer Doudna for "the development of a method for genome editing".
See also[edit]
CRISPR/Cpf1
RNA editing
Epigenome editing
Prime editing
Transposons as a genetic tool
Germinal choice technology
NgAgo, a ssDNA-guided Argonaute endonuclease | biology | 4745712 | https://sv.wikipedia.org/wiki/Cryptolepis%20sinensis | Cryptolepis sinensis | Cryptolepis sinensis är en oleanderväxtart som först beskrevs av Loureiro, och fick sitt nu gällande namn av Elmer Drew Merrill. Cryptolepis sinensis ingår i släktet Cryptolepis och familjen oleanderväxter. Utöver nominatformen finns också underarten C. s. ciliata.
Källor
Externa länkar
Oleanderväxter
sinensis | swedish | 1.220729 |
smallest_genome/genomesofotherorgani.txt | This page has been archived and is no longer updated
# Genomes of Other Organisms: DNA Barcoding and Metagenomics
By: Kira Zhaurova, M.S. ( Nature Education ) © 2008 Nature Education
Citation: Zhaurova, K. (2008) Genomes of other organisms: DNA barcoding and
metagenomics. Nature Education 1( 1 ) :89
[ 
](http://www.reddit.com/submit?url=)
[ 
](https://plus.google.com/share?url=)
[  ](http://twitter.com/share?url=)
[ 
](http://www.facebook.com/share.php?u=)
[  ](javascript:printReadingPage\(\))
The Human Genome Project has been finished—why is it important to look at the
genomes of other species? Species inventory projects can reveal insights into
biodiversity and utility for humans.
[ Aa ](javascript:resizeFontScitable\('fontSize11'\)) [ Aa
](javascript:resizeFontScitable\('fontSize15'\)) [ Aa
](javascript:resizeFontScitable\('fontSize20'\))
##
_Homo sapiens_ are just one of millions of Earth's species . With only about
10% (1.8 million) of all eukaryotic organisms described to date, most such
organisms are yet to be discovered (Hawksworth & Kalin-Arroyo, 1995). To
tackle this immense diversity, scientists often prioritize their efforts by
sampling " biodiversity hotspots" (Figure 1), or areas that harbor unique
and diverse organisms that are often threatened by extinction . Cataloging
biodiversity through species inventory projects is a first step toward
developing an understanding of how various organisms interact with their
environment , which is a key factor in establishing these organisms' roles in
the ecosystem and their potential utility to humankind.
Figure 1: Prominent biodiversity hotspots.
As many as 44% of all species of vascular plants and 35% of all species in
four vertebrate groups are confined to 25 hotspots comprising only 1.4% of the
land surface of the Earth.
© 2000 [ Nature Publishing Group ](http://www.nature.com) Myers, N. _et al._
Biodiversity hotspots for conservation priorities. _Nature_ **403,** 853
(2000). All rights reserved. [  ](javascript:show_inform\("Terms of
Use", "Nature Education has been granted permission to this material in
Scitable but is not authorized to sublicense you to use this material outside
of Scitable except for the following two circumstances. You may reproduce
this material, without modifications, in print form for your personal, non-
commercial use or in print form for non-commercial use in an educational
environment. To obtain permission for usage beyond these cases, please
contact the original publisher."\);)
## Full Genome Sequences
It would be ideal if we could have a giant database of full genome sequences
of all living species. For now, however, scientists are overwhelmed with the
data generated from sequencing only a few dozen genomes. Although this data
provides the virtual map of an organism , some questions can be answered
using fairly short gene sequences. The race is currently on to make genome
sequencing faster, cheaper, and much more efficient. Complete sequences of a
growing number of genomes (e.g., mouse, fruit fly, cat, dog, ape, and human)
allow us to compare the DNA of closely related species in order to establish
and analyze their genetic differences, a field known as _ comparative genomics
_ .
For example, after full genome sequences of humans and several apes became
available, scientists were eager to find out what genes set us apart from
our closest living relative, the bonobo. Researchers thus compared the two
sequences to establish the amount and type of genetic variation . It turns
out that the human and ape genomes are remarkably similar; in fact, a recent
comparison of the two found a nucleotide divergence of only 1.23%
(Mikkelsen _et al_ ., 2005). To better appreciate the scale of this
variation, consider the fact that African and European human populations
exhibit 0.08% nucleotide divergence (Yu _et al._ , 2002). Knowing that all
genes do not evolve at the same rate, researchers were also able to isolate
those human alleles that have undergone the most change since the human and
ape lineages split about 2 million years ago. This knowledge was then used to
determine our rate of evolutionary divergence from the great apes, thus
helping calibrate the molecular clock used to build the primate family tree.
To further fine-tune this clock, efforts are now underway to sequence the full
genome of our closest extinct relative, the Neanderthal. This is no easy task:
fossils are often contaminated by bacteria and human samples, thus causing
the authentic DNA to become fragmented and degraded. However, persistence and
a few well-preserved bones have taken us one million base pairs closer to the
goal of obtaining the full nuclear genome of the Neanderthal (Green _et al._ ,
2006). One of the first major discoveries to come out of working with the
Neanderthal genome fragments is the presence in Neanderthal DNA of the modern
human _FOXP2_ gene , which is known to play a role in speech development .
_FOXP2_ was also found in the genes of the common ancestor of humans and
Neanderthals, which may mean that language has been around for much longer
than we initially supposed (Krause _et al._ , 2007). Major milestones in this
field are achieved quite rapidly; at the time this article was authored,
scientists unveiled the full mitochondrial genome sequence of a 38,000-year
old Neanderthal bone fossil. The full nuclear genome of our last extinct
relative is to follow shortly thereafter (Green, et. al., 2008). Such
discoveries hold great potential for identifying the key genes that helped
spawn human civilization.
Some argue that given the rate of current advances in cloning technology, a
full genome sequence can be viewed as species' "insurance policy" that will
guarantee that it doesn't become extinct. But even as we advance our cloning
and sequencing methods, the availability of a genetic sequence is no guarantee
of long-term species survival, especially for an organism that inhabits a
unique and threatened habitat , or a narrow trophic niche .
## Partial Gene Sequences
The method of comparative genomics can be applied not just to full genome
sequences, but also to single genes and gene fragments to study their
function and help establish relationships among species. Indeed, a species'
place on an evolutionary tree is a valuable predictor of the structure and
function of neighboring taxa.
The current convention of describing (defining) organisms new to science and
establishing their evolutionary relationships is based on total evidence; in
other words, the organisms' genetic, morphological, and ecological characters
are described and analyzed against other sets of data. Taken together, these
techniques can be very informative, having thus far provided us with a
detailed road map of Earth's biota. But for systematics - the study of
biological diversity and common ancestry - rapid technological advances in the
field of comparative genomics are both a blessing and a curse. Consider, for
example, the technique called DNA bar coding, which is based on using short
fragments of mitochondrial gene _CO1_ to uniquely identify and document animal
species (Savolainen, 2005). This technique has applications across all living
organisms, but the precise genetic methodology is still being developed. In
addition, the debate among scientists regarding the use and the utility of DNA
bar coding has been quite vociferous. On one hand, this technique brings the
promise of instant species identification to a much wider community with
minimal biological training. Indeed, it is hypothetically possible to carry a
hand-held device out in the field and input species sequences into a rapidly
expanding database; all for a fraction of the price, knowledge, and effort
associated with the conventional manual method or with human-curated taxonomic
identification. So what's the catch?
One major problem with DNA bar coding is that it operates on the assumption
that species have evolved in perfect percentile distances of genetic
diversion. Thus, with this technique, in order for any two organisms to be
deemed the same species, they must share 88-98% of genetic code at the
chosen _CO1_ mitochondrial gene fragment (Savolainen, 2005). The exact
suggested threshold has to be characterized for each group, and neither the
threshold nor the groups have been clearly defined for most taxa. Thus, DNA
bar coding has been called a "quick fix" and an oversimplification of
systematics. Indeed, wide variation in the _CO1_ gene is found not only among
species, but also within them, and even between the cells of an individual
organism - a phenomenon known as mitochondrial heteroplasmy (Kmiec &
Woloszynska, 2006). Furthermore, there is a broad overlap of inter- and
intraspecific genetic distances among closely related species (Goldstein _et
al._ , 2000).
These issues come into focus when you consider the devastating malaria
epidemic that kills one to three million people worldwide every year. The
pathogens that cause malaria are protozoan parasites from the genus
_Plasmodium_ that are transmitted through the bite of mosquitoes of the genus
_Anopheles_ . Both of these animal genera contain hundreds of species,
although only a few are involved in transmitting malaria in humans. Recent
genetic studies of the symbiotic bacteria in the midgut of the _Anopheles
stephensi_ mosquitoes have yielded promising results: _Enterobacter
agglomerans_ bacteria were genetically engineered to display two anti-
_Plasmodium_ effector molecules that kill the parasite before it is
transmitted to humans (Riehle _et al._ , 2007). Now consider the genetic and
physiological differences between the wild-type and genetically modified
_Anopheles stephensi_ mosquitoes: they are still the same species by all major
standards of species definition, yet what a difference it would make for
humankind if the _Plasmodium-_ resistant genetically modified strain were
dominant . This example highlights the importance of studying genomes and
biological associations of the narrowest niches of life. It also underlines
the vital potential for the unpredictable outcomes of genome sequencing-major
advances are often made using information generated for completely unrelated
reasons.
## Metagenomic Studies
Figure 2: Industrial enzymes - from the metagenome to the applications and
processes.
A library of cloned DNA is produced from the metagenome. Primary screening,
including both sequence-based screening and activity-based screening, produces
enzyme libraries that serve as platforms for subsequent development. Secondary
screening of the enzyme library identifies process-specific properties such as
substrate specificity, activity, and stability. Subsets of cloned enzymes are
then used in scale-up applications or process testing to identify suitable
enzyme candidates.
© 2005 [ Nature Publishing Group ](http://www.nature.com) Lorenz, P. _et al._
Metagenomics and industrial applications. _Nature Reviews Microbiology_ **3,**
512 (2005). All rights reserved. [  ](javascript:show_inform\("Terms of
Use", "Nature Education has been granted permission to this material in
Scitable but is not authorized to sublicense you to use this material outside
of Scitable except for the following two circumstances. You may reproduce
this material, without modifications, in print form for your personal, non-
commercial use or in print form for non-commercial use in an educational
environment. To obtain permission for usage beyond these cases, please
contact the original publisher."\);)
But what about species that are difficult to manipulate in the lab? The
majority of bacteria and archaea are very poorly known, in part because they
occupy virtually all ecological niches, and in part because they are often
very challenging to collect and culture. One very convenient place to begin
exploring these elusive organisms is within our own bodies. The Human
Microbiome Project is an international multi-million dollar effort designed
"to study the microbial communities inhabiting several regions of the human
body, including the gastrointestinal and female urogenital tracts, oral
cavity, nasal and pharyngeal tract, and skin, and how those communities
influence human health and disease ." (Blow, 2008). This work also allows
for a number of fascinating inferences outside the medical field. Take, for
instance, the bacterium Helicobacter pylori: it is found in the majority of
human stomachs and can occasionally cause gastric distress. Analysis of the
polymorphic parts of this bacterium's genome allowed for the reconstruction
of its world-wide dispersal pattern, along with that of its carriers. The
most ancestral strain is found in Africa, and the data from seven other
distinct geographical variants allowed scientists to develop a dispersal
model that corresponds to the pattern of human migration (Falush, 2003). As
globalization continues to increase the rates of microbial transmission, it
becomes more and more crucial to study these organisms, for they play a major
role in regulating our body's functions.
Of course, other bacterial biomes are far greater than our body, and
consequently, they are not investigated as extensively. The vast majority of
microorganisms from the oceanic strata , for example, remain virtually
unknown. Scientists have taken a "shotgun" approach to this dilemma by
sequencing genetic material found in the ocean waters. This method of
obtaining DNA directly from non-lab samples is called metagenomics, and it is
revamping the field of microbial oceanography by tapping a rich source of
genetic diversity.
In addition to focusing on the complete genome sequences obtained by
metagenomic sampling, functional inventories often skip a step by going
directly for the gene products, rather than getting to know the organisms that
produce them (Figure 2). Such studies focus on investigating the functional
aspects of the environment, allowing scientists to directly infer habitat-
specific metabolic demands by targeting the proteins encoded by a community.
In a study that analyzed soil and environment samples from 3 deep-ocean whale
skeletons, Tringe, et. al. (2005) highlighted significant differences in
energy production and population density among the three communities.
Despite these intriguing findings, large proportions of the gene fragments
discovered in the course of this and similar studies remains unidentified.
Often times, however, the sequence data alone is sufficient to predict factors
like energy sources and pollution levels of a given environment. The potential
of metagenomic studies is therefore truly astonishing, and the commercial
incentive is equally great. Gene fragments obtained in the course of
metagenomic research can be expressed in E. coli, for example, to produce
molecular materials that can then be used by the biotechnology and
pharmaceutical industries in product and drug development (Handelsman,
2004).
As a result of this ever-expanding amount of genomic data and the availability
of progressively more efficient sampling, sequencing, and data-storage
technologies, we are seeing rapid advances in the discovery of new genes, gene
products and organisms. Genome sequencing is more affordable than ever; in
fact, we are nearing the benchmark of a "$1,000 genome" (Wolinsky, 2007).
## References and Recommended Reading
* * *
Allen, E., & Banfield, J. Community genomics in microbial ecology and
evolution. _Nature Review Microbiology_ **3** , 489–498 (2005)
doi:10.1038/nrmicro1157 ( [ link to article ](/scitable/content/Community-
genomics-in-microbial-ecology-and-evolution-16687 "link to article") )
Blow, N. Technology feature: Metagenomics-Exploring unseen communities.
_Nature_ **453** , 687–690 (2008) doi:10.1038/453687a ( [ link to article
](/scitable/content/Metagenomics-Exploring-unseen-communities-16767 "link to
article") )
Falush, D., et. al., Traces of human migrations in Helicobacter pylori
populations, _Science_ **299** , 1582-1585 (2003)
Goldstein, P. Z., _et al_ . Conservation genetics at the species boundary.
_Conservation_ _Biology_ **14** , 120–131 (2000)
doi:10.1046/j.1523-1739.2000.98122.x
Green, R. E., _et al_ . Analysis of one million base pairs of Neanderthal DNA.
_Nature_ **444** , 330–336 (2006) doi:10.1038/nature05336 ( [ link to article
](/scitable/content/Analysis-of-one-million-base-pairs-of-13396 "link to
article") )
———. [ A complete Neandertal mitochondrial genome sequence determined by high-
throughput sequencing
](http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WSN-4T5BPWS-C&_user=906544&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_version=1&_urlVersion=0&_userid=906544&md5=96488458156942b72be45034698f6cdc
"A complete Neandertal mitochondrial genome sequence determined by high-
throughput sequencing") . _Cell_ **134** (3): 416–428 (2008)
doi:10.1016/j.cell.2008.06.021
Handelsman, J. Metagenomics: Application of genomics to uncultured organisms.
_Microbiology and Molecular Biology Reviews_ **68** , 669–685 (2004)
doi:10.1128/MBR.68.4.669-685.2004
Hawksworth, D. L., & Kalin-Arroyo, M. T. Magnitude and distribution of
biodiversity. In _Global Biodiversity Assessment_ , __ ed. V. H. Heywood
(Cambridge, Cambridge University Press, 1995)
Kmiec, B., _et al_ . Heteroplasmy as a common state of mitochondrial genetic
information in plants and animals. _Current Genetics_ **50** , 149–159 (2006)
Krause, J., _et al._ The derived _FOXP2_ variant of modern humans was shared
with Neanderthals. _Current Biology_ **17** , 1908–1912 (2007)
Lorenz, P., & Jurgen, E. Metagenomics and industrial applications, _Nature
Reviews Microbiology_ **3** , 510-516 (2005), doi:10.1038/nrmicro1161 ( [ link
to article ](/scitable/content/Metagenomics-and-industrial-applications-56052
"link to article") )
Mikkelsen, T. S., _et al_ . Initial sequence of the chimpanzee genome and
comparison with the human genome. _Nature_ **437** , 69–87 (2005)
doi:10.1038/nature04072 ( [ link to article ](/scitable/content/Initial-
sequence-of-the-chimpanzee-genome-and-13407 "link to article") )
Morgan, J. [ First complete Neanderthal genome sequenced
](http://www.nature.com/news/2008/080807/full/news.2008.1026.html "First
complete Neanderthal genome sequenced") . _Nature News_ : August 7 (2008)
doi:10.1038/news.2008.1026
Myers, N., _et al_ . Biodiversity hotspots for conservation priorities.
_Nature_ **403** , 853–858 (2000) doi: 10.1038/35002501 ( [ link to article
](/scitable/content/Biodiversity-hotspots-for-conservation-priorities-11837
"link to article") )
Riehle, M. A., _et al_ . Using bacteria to express and display anti-
_Plasmodium_ molecules in the mosquito midgut. _International Journal of
Parasitology_ **37** , 595–603 (2007)
Savolainen, V., _et al_ . Towards writing the encyclopaedia of life: An
introduction to DNA bar coding. _Philosophical Transactions of the Royal
Society_ **360** , 1805–1811 (2005)
Tringe, S. G. _et al._ Comparative metagenomics of microbial communities.
_Science_ **308** , 554-557 (2005)
Wolinsky, H. The thousand-dollar genome. _European Molecular Biology
Organization Reports_ **8** , 900–903 (2007) doi:10.1038/sj.embor.7401070.pdf
( [ link to article ](/scitable/content/The-thousand-dollar-genome-Genetic-
brinkmanship-or-17071 "link to article") )
Yu, N., _et al_ . Larger genetic differences within Africans than between
Africans and Eurasians. _Genetics_ **161** , 269–274 (2002)
* Outline
* |
* Keywords
* |
* Add Content to Group
* 
[ 
](http://www.reddit.com/submit?url=)
[ 
](https://plus.google.com/share?url=)
[  ](http://twitter.com/share?url=)
[ 
](http://www.facebook.com/share.php?u=)
[  ](javascript:printReadingPage\(\))
## Article History
Close
* * *
Share | Cancel
Revoke | Cancel
## Keywords
Keywords for this Article
Add keywords to your Content
Save | Cancel
## Flag Inappropriate
The Content is: Objectionable
Explicit
Offensive
Inaccurate
Comments
Flag Content | Cancel
Close
## share
Close
*  [ Digg ](http://digg.com/submit?url=)
*  [ MySpace ](http://www.myspace.com/Modules/PostTo/Pages/?t=)
*  [ Google+ ](https://plus.google.com/share?url=)
* *  StumbleUpon
## Email your Friend
Your First Name *
Your Last Name *
Your Email Address *
Your Friend's Email address *
Your Message *
Submit | Cancel
* Required
[ Close ](javascript:hideOrigImg\(\);)
This content is currently under construction.
[ Close ](javascript:hideUdvMsg\(\);)
Explore This Subject
Comparative Genomics
[ Genomes of Other Organisms: DNA Barcoding and Metagenomics
](/scitable/topicpage/genomes-of-other-organisms-dna-barcoding-and-662)
[ Interpreting Shared Characteristics: The Platypus Genome
](/scitable/topicpage/interpreting-shared-characteristics-the-platypus-
genome-44568)
[ Microarray-based Comparative Genomic Hybridization (aCGH)
](/scitable/topicpage/microarray-based-comparative-genomic-hybridization-
acgh-45432)
[ Pufferfish and Ancestral Genomes ](/scitable/topicpage/pufferfish-and-
ancestral-genomes-29154)
[ Simple Viral and Bacterial Genomes ](/scitable/topicpage/simple-viral-and-
bacterial-genomes-635)
Genome Sequencing and Annotation
[ Basic Local Alignment Search Tool (BLAST) ](/scitable/topicpage/basic-local-
alignment-search-tool-blast-29096)
[ Complex Genomes: Shotgun Sequencing ](/scitable/topicpage/complex-genomes-
shotgun-sequencing-609)
[ DNA Sequencing Technologies ](/scitable/topicpage/dna-sequencing-
technologies-690)
[ DNA Sequencing Technologies Key to the Human Genome Project
](/scitable/topicpage/dna-sequencing-technologies-key-to-the-human-828)
[ Genomic Data Resources: Challenges and Promises
](/scitable/topicpage/genomic-data-resources-challenges-and-promises-743721)
[ Sequencing Human Genome: the Contributions of Francis Collins and Craig
Venter ](/scitable/topicpage/sequencing-human-genome-the-contributions-of-
francis-686)
Functional Genomics
[ Microarray-based Comparative Genomic Hybridization (aCGH)
](/scitable/topicpage/microarray-based-comparative-genomic-hybridization-
acgh-45432)
[ Ontologies: Scientific Data Sharing Made Easy
](/scitable/topicpage/ontologies-scientific-data-sharing-made-easy-77972)
[ The Proteome: Discovering the Structure and Function of Proteins
](/scitable/topicpage/the-proteome-discovering-the-structure-and-function-613)
[ Transcriptome: Connecting the Genome to Gene Function
](/scitable/topicpage/transcriptome-connecting-the-genome-to-gene-
function-605)
Translational Genomics
[ Behavioral Genomics ](/scitable/topicpage/behavioral-genomics-29093)
[ Comparative Methylation Hybridization ](/scitable/topicpage/comparative-
methylation-hybridization-27920)
[ DNA Fingerprinting Using Amplified Fragment Length Polymorphisms (AFLP)
](/scitable/topicpage/dna-fingerprinting-using-amplified-fragment-length-
polymorphisms-39051)
[ Epigenomics: The New Tool in Studying Complex Diseases
](/scitable/topicpage/epigenomics-the-new-tool-in-studying-complex-694)
[ Pharmacogenomics and Personalized Medicine
](/scitable/topicpage/pharmacogenomics-and-personalized-medicine-643)
[ Sustainable Bioenergy: Genomics and Biofuels Development
](/scitable/topicpage/sustainable-bioenergy-genomics-and-biofuels-
development-44571)
## Topic rooms within Genomics
[ Close ](javascript:hideLearnMoreLB\(\))
**No topic rooms are there.**
[ 
](/scitable/topic/genomics-19)
* | Lead Editor: [ Michael Goldman ](/scitable/topicpage/michael-goldman-lead-editor-37590 "Michael Goldman") , [ Christopher D. Smith ](/scitable/topicpage/chris-smith-lead-editor-37571 "Christopher D. Smith")
[ Genomics ](/scitable/topic/genomics-19)
 Loading ...
Within this Subject (21)
* Comparative Genomics (5)
* Functional Genomics (4)
* Genome Sequencing and Annotation (6)
* Translational Genomics (6)
Or Browse Visually
Other Topic Rooms
[ Genetics ](/scitable/topic/genetics-5)
* [ Gene Inheritance and Transmission ](/scitable/topic/gene-inheritance-and-transmission-23)
* [ Gene Expression and Regulation ](/scitable/topic/gene-expression-and-regulation-15)
* [ Nucleic Acid Structure and Function ](/scitable/topic/nucleic-acid-structure-and-function-9)
* [ Chromosomes and Cytogenetics ](/scitable/topic/chromosomes-and-cytogenetics-7)
* [ Evolutionary Genetics ](/scitable/topic/evolutionary-genetics-13)
* [ Population and Quantitative Genetics ](/scitable/topic/population-and-quantitative-genetics-21)
* [ Genomics ](/scitable/topic/genomics-19)
* [ Genes and Disease ](/scitable/topic/genes-and-disease-17)
* [ Genetics and Society ](/scitable/topic/genetics-and-society-11)
[ Cell Biology ](/scitable/topic/cell-biology-13906536)
* [ Cell Origins and Metabolism ](/scitable/topic/cell-origins-and-metabolism-14122694)
* [ Proteins and Gene Expression ](/scitable/topic/proteins-and-gene-expression-14122688)
* [ Subcellular Compartments ](/scitable/topic/subcellular-compartments-14122679)
* [ Cell Communication ](/scitable/topic/cell-communication-14122659)
* [ Cell Cycle and Cell Division ](/scitable/topic/cell-cycle-and-cell-division-14122649)
[ Scientific Communication ](/scitable/topic/scientific-
communication-14121566)
[ Career Planning ](/scitable/topic/career-planning-14121550)
 Loading ...
* [  ](http://www.nature.com/scitable/blog/student-voices)
[ Student Voices ](http://www.nature.com/scitable/blog/student-voices)
* [  ](http://www.nature.com/scitable/blog/creature-cast)
[ Creature Cast ](http://www.nature.com/scitable/blog/creature-cast)
* [  ](http://www.nature.com/scitable/blog/natureedcast)
[ NatureEdCast ](http://www.nature.com/scitable/blog/natureedcast)
* [  ](http://www.nature.com/scitable/blog/simply-science)
[ Simply Science ](http://www.nature.com/scitable/blog/simply-science)
* [  ](http://www.nature.com/scitable/blog/green-screen)
[ Green Screen ](http://www.nature.com/scitable/blog/green-screen)
* [  ](http://www.nature.com/scitable/blog/conferencecast)
[ ConferenceCast ](http://www.nature.com/scitable/blog/conferencecast)
* [  ](http://www.nature.com/scitable/blog/green-science)
[ Green Science ](http://www.nature.com/scitable/blog/green-science)
* [  ](http://www.nature.com/scitable/blog/bio2.0)
[ Bio 2.0 ](http://www.nature.com/scitable/blog/bio2.0)
* [  ](http://www.nature.com/scitable/blog/viruses101)
[ Viruses101 ](http://www.nature.com/scitable/blog/viruses101)
* [  ](http://www.nature.com/scitable/blog/scholarcast)
[ ScholarCast ](http://www.nature.com/scitable/blog/scholarcast)
* [  ](http://www.nature.com/scitable/blog/the-success-code)
[ The Success Code ](http://www.nature.com/scitable/blog/the-success-code)
* [  ](http://www.nature.com/scitable/blog/why-science-matters)
[ Why Science Matters ](http://www.nature.com/scitable/blog/why-science-
matters)
* [  ](http://www.nature.com/scitable/blog/earthbound)
[ Earthbound ](http://www.nature.com/scitable/blog/earthbound)
* [  ](http://www.nature.com/scitable/blog/thebeyond)
[ The Beyond ](http://www.nature.com/scitable/blog/thebeyond)
* [  ](http://www.nature.com/scitable/blog/plantchemcast)
[ Plant ChemCast ](http://www.nature.com/scitable/blog/plantchemcast)
* [  ](http://www.nature.com/scitable/blog/pop)
[ Pop ](http://www.nature.com/scitable/blog/pop)
* [  ](http://www.nature.com/scitable/blog/scibytes)
[ SciBytes ](http://www.nature.com/scitable/blog/scibytes)
* [  ](http://www.nature.com/scitable/blog/postcards-from-the-universe)
[ Postcards from the Universe ](http://www.nature.com/scitable/blog/postcards-
from-the-universe)
* [  ](http://www.nature.com/scitable/blog/brain-metrics)
[ Brain Metrics ](http://www.nature.com/scitable/blog/brain-metrics)
* [  ](http://www.nature.com/scitable/blog/mind-read)
[ Mind Read ](http://www.nature.com/scitable/blog/mind-read)
* [  ](http://www.nature.com/scitable/blog/eyes-on-environment)
[ Eyes on Environment ](http://www.nature.com/scitable/blog/eyes-on-
environment)
* [  ](http://www.nature.com/scitable/blog/accumulating-glitches)
[ Accumulating Glitches ](http://www.nature.com/scitable/blog/accumulating-
glitches)
* [  ](http://www.nature.com/scitable/blog/saltwater-science)
[ Saltwater Science ](http://www.nature.com/scitable/blog/saltwater-science)
* [  ](http://www.nature.com/scitable/blog/microbe-matters)
[ Microbe Matters ](http://www.nature.com/scitable/blog/microbe-matters)
[ « ](javascript:showFirstLatestBlogs\(\);) [ Prev
](javascript:showPrevLatestBlogs\(\)) « Prev [ Next
](javascript:showNextLatestBlogs\(\)) [ »
](javascript:showLastLatestBlogs\(\);) Next »
LearnCast
You have authorized LearnCasting of your reading list in Scitable. Do you want
to LearnCast this session?
[ Yes ](javascript:shareWithFBValidator\(\))
[ No ](javascript:minimizeAutoShareFBWin\(\))
This article has been posted to your Facebook page via Scitable LearnCast.
[ Close ](javascript:minimizeAutoShareFBWin\(\))
[ Change LearnCast Settings ](/scitable/my-profile/social-settings)
© 2014 Nature Education
* [ About ](/scitable/about) |
* [ Contact ](/scitable/contact) |
* [ Press Room ](/scitable/pressnews) |
* [ Sponsors ](/scitable/sponsors) |
* [ Terms of Use ](/scitable/viewTermsOfUse) |
* [ Privacy Notice ](/scitable/privacyPolicy) |
* [ Glossary ](/scitable/glossary) |
* [ Catalog ](/scitable/library) |
* [ Home ](/scitable) |
* [ Library ](/scitable/topics) |
* [ Blogs ](/scitable/blogs)
Scitable Chat
* 
* 
* 
* * *
[
](/scitable/whatisscitable "About") [
](/scitable/faculty-page "Faculty Page") [
](/scitable/study-center "Students Page")
* [  ](/scitable)
* 
* [  ](/scitable/topics)
* 
* [  ](/scitable/blogs)
* 
* [  ](http://www.nature.com/naturejobs/science/?WT.mc_id=WEB_NatureJobs_1504_SCITABLE)
*
* [  ](javascript:checkField\(\))
* * [ Register ](javascript:DisplayRegisterPage\(\);)
* |
* [ Sign In ](javascript:DisplaySignInPage\(\);)
* * *
## Visual Browse
Close
| biology | 2629407 | https://sv.wikipedia.org/wiki/Typophyllum%20scissifolium | Typophyllum scissifolium | Typophyllum scissifolium är en insektsart som beskrevs av Walker, F. 1870. Typophyllum scissifolium ingår i släktet Typophyllum och familjen vårtbitare. Inga underarter finns listade i Catalogue of Life.
Källor
Vårtbitare
scissifolium | swedish | 0.970866 |
smallest_genome/Genome.txt |
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding genes, other functional regions of the genome such as regulatory sequences (see non-coding DNA), and often a substantial fraction of junk DNA with no evident function. Almost all eukaryotes have mitochondria and a small mitochondrial genome. Algae and plants also contain chloroplasts with a chloroplast genome.
The study of the genome is called genomics. The genomes of many organisms have been sequenced and various regions have been annotated. The Human Genome Project was started in October 1990, and then reported the sequence of the human genome in April 2003, although the initial "finished" sequence was missing 8% of the genome consisting mostly of repetitive sequences.
With advancements in technology that could handle sequencing of the many repetitive sequences found in human DNA that were not fully uncovered by the original Human Genome Project study, scientists reported the first end-to-end human genome sequence in March 2022.
Origin of the term[edit]
Look up genome in Wiktionary, the free dictionary.
The term genome was created in 1920 by Hans Winkler, professor of botany at the University of Hamburg, Germany. The website Oxford Dictionaries and the Online Etymology Dictionary suggest the name is a blend of the words gene and chromosome. However, see omics for a more thorough discussion. A few related -ome words already existed, such as biome and rhizome, forming a vocabulary into which genome fits systematically.
Definition[edit]
It's very difficult to come up with a precise definition of "genome." It usually refers to the DNA (or sometimes RNA) molecules that carry the genetic information in an organism but sometimes it is difficult to decide which molecules to include in the definition; for example, bacteria usually have one or two large DNA molecules (chromosomes) that contain all of the essential genetic material but they also contain smaller extrachromosomal plasmid molecules that carry important genetic information. The definition of 'genome' that's commonly used in the scientific literature is usually restricted to the large chromosomal DNA molecules in bacteria.
Nuclear genome[edit]
Eukaryotic genomes are even more difficult to define because almost all eukaryotic species contain nuclear chromosomes plus extra DNA molecules in the mitochondria. In addition, algae and plants have chloroplast DNA. Most textbooks make a distinction between the nuclear genome and the organelle (mitochondria and chloroplast) genomes so when they speak of, say, the human genome, they are only referring to the genetic material in the nucleus. This is the most common use of 'genome' in the scientific literature.
Ploidy[edit]
Most eukaryotes are diploid, meaning that there are two of each chromosome in the nucleus but the 'genome' refers to only one copy of each chromosome. Some eukaryotes have distinctive sex chromosomes, such as the X and Y chromosomes of mammals, so the technical definition of the genome must include both copies of the sex chromosomes. For example, the standard reference genome of humans consists of one copy of each of the 22 autosomes plus one X chromosome and one Y chromosome.
Sequencing and mapping[edit]
Further information: Whole genome sequencing and Genome project
A genome sequence is the complete list of the nucleotides (A, C, G, and T for DNA genomes) that make up all the chromosomes of an individual or a species. Within a species, the vast majority of nucleotides are identical between individuals, but sequencing multiple individuals is necessary to understand the genetic diversity.
Part of DNA sequence – prototypification of complete genome of virus
In 1976, Walter Fiers at the University of Ghent (Belgium) was the first to establish the complete nucleotide sequence of a viral RNA-genome (Bacteriophage MS2). The next year, Fred Sanger completed the first DNA-genome sequence: Phage Φ-X174, of 5386 base pairs. The first bacterial genome to be sequenced was that of Haemophilus influenzae, completed by a team at The Institute for Genomic Research in 1995. A few months later, the first eukaryotic genome was completed, with sequences of the 16 chromosomes of budding yeast Saccharomyces cerevisiae published as the result of a European-led effort begun in the mid-1980s. The first genome sequence for an archaeon, Methanococcus jannaschii, was completed in 1996, again by The Institute for Genomic Research.
The development of new technologies has made genome sequencing dramatically cheaper and easier, and the number of complete genome sequences is growing rapidly. The US National Institutes of Health maintains one of several comprehensive databases of genomic information. Among the thousands of completed genome sequencing projects include those for rice, a mouse, the plant Arabidopsis thaliana, the puffer fish, and the bacteria E. coli. In December 2013, scientists first sequenced the entire genome of a Neanderthal, an extinct species of humans. The genome was extracted from the toe bone of a 130,000-year-old Neanderthal found in a Siberian cave.
New sequencing technologies, such as massive parallel sequencing have also opened up the prospect of personal genome sequencing as a diagnostic tool, as pioneered by Manteia Predictive Medicine. A major step toward that goal was the completion in 2007 of the full genome of James D. Watson, one of the co-discoverers of the structure of DNA.
Whereas a genome sequence lists the order of every DNA base in a genome, a genome map identifies the landmarks. A genome map is less detailed than a genome sequence and aids in navigating around the genome. The Human Genome Project was organized to map and to sequence the human genome. A fundamental step in the project was the release of a detailed genomic map by Jean Weissenbach and his team at the Genoscope in Paris.
Reference genome sequences and maps continue to be updated, removing errors and clarifying regions of high allelic complexity. The decreasing cost of genomic mapping has permitted genealogical sites to offer it as a service, to the extent that one may submit one's genome to crowdsourced scientific endeavours such as DNA.LAND at the New York Genome Center, an example both of the economies of scale and of citizen science.
Viral genomes[edit]
Viral genomes can be composed of either RNA or DNA. The genomes of RNA viruses can be either single-stranded RNA or double-stranded RNA, and may contain one or more separate RNA molecules (segments: monopartit or multipartit genome). DNA viruses can have either single-stranded or double-stranded genomes. Most DNA virus genomes are composed of a single, linear molecule of DNA, but some are made up of a circular DNA molecule.
Prokaryotic genomes[edit]
Prokaryotes and eukaryotes have DNA genomes. Archaea and most bacteria have a single circular chromosome, however, some bacterial species have linear or multiple chromosomes. If the DNA is replicated faster than the bacterial cells divide, multiple copies of the chromosome can be present in a single cell, and if the cells divide faster than the DNA can be replicated, multiple replication of the chromosome is initiated before the division occurs, allowing daughter cells to inherit complete genomes and already partially replicated chromosomes. Most prokaryotes have very little repetitive DNA in their genomes. However, some symbiotic bacteria (e.g. Serratia symbiotica) have reduced genomes and a high fraction of pseudogenes: only ~40% of their DNA encodes proteins.
Some bacteria have auxiliary genetic material, also part of their genome, which is carried in plasmids. For this, the word genome should not be used as a synonym of chromosome.
Eukaryotic genomes[edit]
See also: Eukaryotic chromosome fine structure
In a typical human cell, the genome is contained in 22 pairs of autosomes, two sex chromosomes (the female and male variants shown at bottom right), as well as the mitochondrial genome (shown to scale as "MT" at bottom left). Further information: Karyotype
Eukaryotic genomes are composed of one or more linear DNA chromosomes. The number of chromosomes varies widely from Jack jumper ants and an asexual nemotode, which each have only one pair, to a fern species that has 720 pairs. It is surprising the amount of DNA that eukaryotic genomes contain compared to other genomes. The amount is even more than what is necessary for DNA protein-coding and noncoding genes due to the fact that eukaryotic genomes show as much as 64,000-fold variation in their sizes. However, this special characteristic is caused by the presence of repetitive DNA, and transposable elements (TEs).
A typical human cell has two copies of each of 22 autosomes, one inherited from each parent, plus two sex chromosomes, making it diploid. Gametes, such as ova, sperm, spores, and pollen, are haploid, meaning they carry only one copy of each chromosome. In addition to the chromosomes in the nucleus, organelles such as the chloroplasts and mitochondria have their own DNA. Mitochondria are sometimes said to have their own genome often referred to as the "mitochondrial genome". The DNA found within the chloroplast may be referred to as the "plastome". Like the bacteria they originated from, mitochondria and chloroplasts have a circular chromosome.
Unlike prokaryotes where exon-intron organization of protein coding genes exists but is rather exceptional, eukaryotes generally have these features in their genes and their genomes contain variable amounts of repetitive DNA. In mammals and plants, the majority of the genome is composed of repetitive DNA. Genes in eukaryotic genomes can be annotated using FINDER.
DNA sequencing[edit]
High-throughput technology makes sequencing to assemble new genomes accessible to everyone. Sequence polymorphisms are typically discovered by comparing resequenced isolates to a reference, whereas analyses of coverage depth and mapping topology can provide details regarding structural variations such as chromosomal translocations and segmental duplications.
Coding sequences[edit]
DNA sequences that carry the instructions to make proteins are referred to as coding sequences. The proportion of the genome occupied by coding sequences varies widely. A larger genome does not necessarily contain more genes, and the proportion of non-repetitive DNA decreases along with increasing genome size in complex eukaryotes.
Composition of the human genome
Noncoding sequences[edit]
Main article: Non-coding DNA
See also: Intergenic region
Noncoding sequences include introns, sequences for non-coding RNAs, regulatory regions, and repetitive DNA. Noncoding sequences make up 98% of the human genome. There are two categories of repetitive DNA in the genome: tandem repeats and interspersed repeats.
Tandem repeats[edit]
Short, non-coding sequences that are repeated head-to-tail are called tandem repeats. Microsatellites consisting of 2–5 basepair repeats, while minisatellite repeats are 30–35 bp. Tandem repeats make up about 4% of the human genome and 9% of the fruit fly genome. Tandem repeats can be functional. For example, telomeres are composed of the tandem repeat TTAGGG in mammals, and they play an important role in protecting the ends of the chromosome.
In other cases, expansions in the number of tandem repeats in exons or introns can cause disease. For example, the human gene huntingtin (Htt) typically contains 6–29 tandem repeats of the nucleotides CAG (encoding a polyglutamine tract). An expansion to over 36 repeats results in Huntington's disease, a neurodegenerative disease. Twenty human disorders are known to result from similar tandem repeat expansions in various genes. The mechanism by which proteins with expanded polygulatamine tracts cause death of neurons is not fully understood. One possibility is that the proteins fail to fold properly and avoid degradation, instead accumulating in aggregates that also sequester important transcription factors, thereby altering gene expression.
Tandem repeats are usually caused by slippage during replication, unequal crossing-over and gene conversion.
Transposable elements[edit]
Transposable elements (TEs) are sequences of DNA with a defined structure that are able to change their location in the genome. TEs are categorized as either as a mechanism that replicates by copy-and-paste or as a mechanism that can be excised from the genome and inserted at a new location. In the human genome, there are three important classes of TEs that make up more than 45% of the human DNA; these classes are The long interspersed nuclear elements (LINEs), The interspersed nuclear elements (SINEs), and endogenous retroviruses. These elements have a big potential to modify the genetic control in a host organism.
The movement of TEs is a driving force of genome evolution in eukaryotes because their insertion can disrupt gene functions, homologous recombination between TEs can produce duplications, and TE can shuffle exons and regulatory sequences to new locations.
Retrotransposons[edit]
Retrotransposons are found mostly in eukaryotes but not found in prokaryotes. Retrotransposons form a large portion of the genomes of many eukaryotes. A retrotransposon is a transposable element that transposes through an RNA intermediate. Retrotransposons are composed of DNA, but are transcribed into RNA for transposition, then the RNA transcript is copied back to DNA formation with the help of a specific enzyme called reverse transcriptase. A retrotransposon that carries reverse transcriptase in its sequence can trigger its own transposition but retrotransposons that lack a reverse transcriptase must use reverse transcriptase synthesized by another retrotransposon. Retrotransposons can be transcribed into RNA, which are then duplicated at another site into the genome. Retrotransposons can be divided into long terminal repeats (LTRs) and non-long terminal repeats (Non-LTRs).
Long terminal repeats (LTRs) are derived from ancient retroviral infections, so they encode proteins related to retroviral proteins including gag (structural proteins of the virus), pol (reverse transcriptase and integrase), pro (protease), and in some cases env (envelope) genes. These genes are flanked by long repeats at both 5' and 3' ends. It has been reported that LTRs consist of the largest fraction in most plant genome and might account for the huge variation in genome size.
Non-long terminal repeats (Non-LTRs) are classified as long interspersed nuclear elements (LINEs), short interspersed nuclear elements (SINEs), and Penelope-like elements (PLEs). In Dictyostelium discoideum, there is another DIRS-like elements belong to Non-LTRs. Non-LTRs are widely spread in eukaryotic genomes.
Long interspersed elements (LINEs) encode genes for reverse transcriptase and endonuclease, making them autonomous transposable elements. The human genome has around 500,000 LINEs, taking around 17% of the genome.
Short interspersed elements (SINEs) are usually less than 500 base pairs and are non-autonomous, so they rely on the proteins encoded by LINEs for transposition. The Alu element is the most common SINE found in primates. It is about 350 base pairs and occupies about 11% of the human genome with around 1,500,000 copies.
DNA transposons[edit]
DNA transposons encode a transposase enzyme between inverted terminal repeats. When expressed, the transposase recognizes the terminal inverted repeats that flank the transposon and catalyzes its excision and reinsertion in a new site. This cut-and-paste mechanism typically reinserts transposons near their original location (within 100kb). DNA transposons are found in bacteria and make up 3% of the human genome and 12% of the genome of the roundworm C. elegans.
Genome size[edit]
Log–log plot of the total number of annotated proteins in genomes submitted to GenBank as a function of genome size
Genome size is the total number of the DNA base pairs in one copy of a haploid genome. Genome size varies widely across species. Invertebrates have small genomes, this is also correlated to a small number of transposable elements. Fish and Amphibians have intermediate-size genomes, and birds have relatively small genomes but it has been suggested that birds lost a substantial portion of their genomes during the phase of transition to flight. Before this loss, DNA methylation allows the adequate expansion of the genome.
In humans, the nuclear genome comprises approximately 3.1 billion nucleotides of DNA, divided into 24 linear molecules, the shortest 45 000 000 nucleotides in length and the longest 248 000 000 nucleotides, each contained in a different chromosome. There is no clear and consistent correlation between morphological complexity and genome size in either prokaryotes or lower eukaryotes. Genome size is largely a function of the expansion and contraction of repetitive DNA elements.
Since genomes are very complex, one research strategy is to reduce the number of genes in a genome to the bare minimum and still have the organism in question survive. There is experimental work being done on minimal genomes for single cell organisms as well as minimal genomes for multi-cellular organisms (see developmental biology). The work is both in vivo and in silico.
Genome size differences due to transposable elements[edit]
Comparison among genome sizes
There are many enormous differences in size in genomes, specially mentioned before in the multicellular eukaryotic genomes. Much of this is due to the differing abundances of transposable elements, which evolve by creating new copies of themselves in the chromosomes. Eukaryote genomes often contain many thousands of copies of these elements, most of which have acquired mutations that make them defective.
Here is a table of some significant or representative genomes. See #See also for lists of sequenced genomes.
Organism type
Organism
Genome size (base pairs)
Approx. no. of genes
Note
Virus
Porcine circovirus type 1
1,759
1.8 kB
Smallest viruses replicating autonomously in eukaryotic cells
Virus
Bacteriophage MS2
3,569
3.6 kB
First sequenced RNA-genome
Virus
SV40
5,224
5.2 kB
Virus
Phage Φ-X174
5,386
5.4 kB
First sequenced DNA-genome
Virus
HIV
9,749
9.7 kB
Virus
Phage λ
48,502
48.5 kB
Often used as a vector for the cloning of recombinant DNA
Virus
Megavirus
1,259,197
1.3 MB
Until 2013 the largest known viral genome
Virus
Pandoravirus salinus
2,470,000
2.47 MB
Largest known viral genome.
Eukaryotic organelle
Human mitochondrion
16,569
16.6 kB
Bacterium
Nasuia deltocephalinicola (strain NAS-ALF)
112,091
112 kB
137
Smallest known non-viral genome. Symbiont of leafhoppers.
Bacterium
Carsonella ruddii
159,662
160 kB
An endosymbiont of psyllid insects
Bacterium
Buchnera aphidicola
600,000
600 kB
An endosymbiont of aphids
Bacterium
Wigglesworthia glossinidia
700,000
700 kB
A symbiont in the gut of the tsetse fly
Bacterium – cyanobacterium
Prochlorococcus spp. (1.7 Mb)
1,700,000
1.7 MB
1,884
Smallest known cyanobacterium genome. One of the primary photosynthesizers on Earth.
Bacterium
Haemophilus influenzae
1,830,000
1.8 MB
First genome of a living organism sequenced, July 1995
Bacterium
Escherichia coli
4,600,000
4.6 MB
4,288
Bacterium – cyanobacterium
Nostoc punctiforme
9,000,000
9 MB
7,432
7432 open reading frames
Bacterium
Solibacter usitatus (strain Ellin 6076)
9,970,000
10 MB
Amoeboid
Polychaos dubium ("Amoeba" dubia)
670,000,000,000
670 GB
Largest known genome. (Disputed)
Plant
Genlisea tuberosa
61,000,000
61 MB
Smallest recorded flowering plant genome, 2014
Plant
Arabidopsis thaliana
135,000,000
135 MB
27,655
First plant genome sequenced, December 2000
Plant
Populus trichocarpa
480,000,000
480 MB
73,013
First tree genome sequenced, September 2006
Plant
Pinus taeda (Loblolly pine)
22,180,000,000
22.18 GB
50,172
Gymnosperms generally have much larger genomes than angiosperms
Plant
Fritillaria assyriaca
130,000,000,000
130 GB
Plant
Paris japonica (Japanese-native, order Liliales)
150,000,000,000
150 GB
Largest plant genome known
Plant – moss
Physcomitrella patens
480,000,000
480 MB
First genome of a bryophyte sequenced, January 2008
Fungus – yeast
Saccharomyces cerevisiae
12,100,000
12.1 MB
6,294
First eukaryotic genome sequenced, 1996
Fungus
Aspergillus nidulans
30,000,000
30 MB
9,541
Nematode
Pratylenchus coffeae
20,000,000
20 MB
Smallest animal genome known
Nematode
Caenorhabditis elegans
100,300,000
100 MB
19,000
First multicellular animal genome sequenced, December 1998
Insect
Belgica antarctica (Antarctic midge)
99,000,000
99 MB
Smallest insect genome sequenced thus far, likely an adaptation to an extreme environment
Insect
Drosophila melanogaster (fruit fly)
175,000,000
175 MB
13,600
Size variation based on strain (175–180 Mb; standard y w strain is 175 Mb)
Insect
Apis mellifera (honey bee)
236,000,000
236 MB
10,157
Insect
Bombyx mori (silk moth)
432,000,000
432 MB
14,623
14,623 predicted genes
Insect
Solenopsis invicta (fire ant)
480,000,000
480 MB
16,569
Crustacean
Antarctic krill
48,010,000,000
48 GB
23,000
70-92% repetitive DNA
Amphibian
Neuse River waterdog
118,000,000,000
118 GB
Largest tetrapod genome sequenced as of 2022
Amphibian
Ornate burrowing frog
1,060,000,000
1.06 GB
Smallest known frog genome
Mammal
Mus musculus
2,700,000,000
2.7 GB
20,210
Mammal
Pan paniscus
3,286,640,000
3.3 GB
20,000
Bonobo – estimated genome size 3.29 billion bp
Mammal
Homo sapiens
3,117,000,000
3.1 GB
20,000
Homo sapiens genome size estimated at 3.12 Gbp in 2022
Initial sequencing and analysis of the human genome
Bird
Gallus gallus
1,043,000,000
1.0 GB
20,000
Fish
Tetraodon nigroviridis (type of puffer fish)
385,000,000
390 MB
Smallest vertebrate genome known, estimated to be 340 Mb – 385 Mb
Fish
Protopterus aethiopicus (marbled lungfish)
130,000,000,000
130 GB
Largest vertebrate genome known
Genomic alterations[edit]
All the cells of an organism originate from a single cell, so they are expected to have identical genomes; however, in some cases, differences arise. Both the process of copying DNA during cell division and exposure to environmental mutagens can result in mutations in somatic cells. In some cases, such mutations lead to cancer because they cause cells to divide more quickly and invade surrounding tissues. In certain lymphocytes in the human immune system, V(D)J recombination generates different genomic sequences such that each cell produces a unique antibody or T cell receptors.
During meiosis, diploid cells divide twice to produce haploid germ cells. During this process, recombination results in a reshuffling of the genetic material from homologous chromosomes so each gamete has a unique genome.
Genome-wide reprogramming[edit]
Genome-wide reprogramming in mouse primordial germ cells involves epigenetic imprint erasure leading to totipotency. Reprogramming is facilitated by active DNA demethylation, a process that entails the DNA base excision repair pathway. This pathway is employed in the erasure of CpG methylation (5mC) in primordial germ cells. The erasure of 5mC occurs via its conversion to 5-hydroxymethylcytosine (5hmC) driven by high levels of the ten-eleven dioxygenase enzymes TET1 and TET2.
Genome evolution[edit]
Genomes are more than the sum of an organism's genes and have traits that may be measured and studied without reference to the details of any particular genes and their products. Researchers compare traits such as karyotype (chromosome number), genome size, gene order, codon usage bias, and GC-content to determine what mechanisms could have produced the great variety of genomes that exist today (for recent overviews, see Brown 2002; Saccone and Pesole 2003; Benfey and Protopapas 2004; Gibson and Muse 2004; Reese 2004; Gregory 2005).
Duplications play a major role in shaping the genome. Duplication may range from extension of short tandem repeats, to duplication of a cluster of genes, and all the way to duplication of entire chromosomes or even entire genomes. Such duplications are probably fundamental to the creation of genetic novelty.
Horizontal gene transfer is invoked to explain how there is often an extreme similarity between small portions of the genomes of two organisms that are otherwise very distantly related. Horizontal gene transfer seems to be common among many microbes. Also, eukaryotic cells seem to have experienced a transfer of some genetic material from their chloroplast and mitochondrial genomes to their nuclear chromosomes. Recent empirical data suggest an important role of viruses and sub-viral RNA-networks to represent a main driving role to generate genetic novelty and natural genome editing.
In fiction[edit]
Works of science fiction illustrate concerns about the availability of genome sequences.
Michael Crichton's 1990 novel Jurassic Park and the subsequent film tell the story of a billionaire who creates a theme park of cloned dinosaurs on a remote island, with disastrous outcomes. A geneticist extracts dinosaur DNA from the blood of ancient mosquitoes and fills in the gaps with DNA from modern species to create several species of dinosaurs. A chaos theorist is asked to give his expert opinion on the safety of engineering an ecosystem with the dinosaurs, and he repeatedly warns that the outcomes of the project will be unpredictable and ultimately uncontrollable. These warnings about the perils of using genomic information are a major theme of the book.
The 1997 film Gattaca is set in a futurist society where genomes of children are engineered to contain the most ideal combination of their parents' traits, and metrics such as risk of heart disease and predicted life expectancy are documented for each person based on their genome. People conceived outside of the eugenics program, known as "In-Valids" suffer discrimination and are relegated to menial occupations. The protagonist of the film is an In-Valid who works to defy the supposed genetic odds and achieve his dream of working as a space navigator. The film warns against a future where genomic information fuels prejudice and extreme class differences between those who can and cannot afford genetically engineered children.
See also[edit]
Bacterial genome size
Cryoconservation of animal genetic resources
Genome Browser
Genome Compiler
Genome topology
Genome-wide association study
List of sequenced animal genomes
List of sequenced archaeal genomes
List of sequenced bacterial genomes
List of sequenced eukaryotic genomes
List of sequenced fungi genomes
List of sequenced plant genomes
List of sequenced plastomes
List of sequenced protist genomes
Metagenomics
Microbiome
Molecular epidemiology
Molecular pathological epidemiology
Molecular pathology
Nucleic acid sequence
Pan-genome
Precision medicine
Regulator gene
Whole genome sequencing | biology | 5284 | https://da.wikipedia.org/wiki/Gen | Gen | Et gen er en biologisk enhed for information kodet i DNA om dannelse af et biologisk molekyle.
Et individs gener kaldes arvemassen eller genomet. Ordet gen indførtes i 1909 af den danske biolog Wilhelm Johannsen. Den klassiske genetik omhandler hvordan gener nedarves, se Gregor Mendel.
Gener indeholder informationen til proteinsyntese i form af sekvensen af baser i DNA. Det kan f.eks. være informationen til fremstilling af et enzym, som f.eks. indgår i nedbrydningen af føden. Andre gener koder for andre proteiner som antistoffer og visse hormoner, transportmolekyler, enzymhæmmere, adhæsionsmolekyler, toksiner, receptorer, lectiner og mikroproteiner.
Atter andre gener koder for rRNA, tRNA og andre RNA-molekyler med forskellige regulerende funktioner.
Forskellige organismer har ikke det samme antal gener. Encellede bakteriers arvemasse har cirka 4.000 gener, en gærcelle har 6.000 gener, planter har et meget varierende antal gener, og dyr har typisk 10-100.000 gener. Mennesket har 20.344 gener der koder for proteiner.
Generne består af DNA og udgør (sammen med proteiner, bl.a. histoner) cellens kromosomer. Det sted, som et gen sidder på et kromosom, kaldes genets locus. Hvert diploid individ har to kopier af hvert gen. En kopi er arvet fra faren og en fra moren. Grundlaget for genetisk variation er, at gener forekommer i funktionelt forskellige former, som betegnes alleler. Forskelle mellem alleler reflekterer forskelle i den DNA-sekvens, som udgør genet.
Ændringer i et gen kaldes mutationer, f.eks. rækkefølgen af basene i DNAet, se f.eks. ændringen af CFTR hvor f.eks. en mangel på tre baser forårsager cystisk fibrose.
Se også
CRISPR
Genetik
Allel
Genteknologi
Arv (genetisk)
Onkogen
Eksterne henvisninger
DR's tema om gener | danish | 0.441212 |
baby_memories/causesofmemorylossin.txt | Close Menu
[ ePaper ](https://epaper.nation.africa/ke)
Kenya Edition
* [ Africa Edition ](https://nation.africa/africa?utm_source=menu&utm_medium=drop_down)
* [ Uganda Edition ](https://www.monitor.co.ug/uganda?utm_source=menu&utm_medium=drop_down)
* [ Tanzania Edition ](https://www.mwananchi.co.tz/mw?utm_source=menu&utm_medium=drop_down)
## [ ](/kenya)
[ Search ](/kenya/search)
Log in Sign up
[ My Account ](/kenya/account)
* [ Personal details ](/kenya/account#personal-details)
* [ Change password ](/kenya/account#change-password)
* [ Purchases ](/kenya/account#purchases)
* Sign out
### [ Health Tips ](/kenya/health)
* [ Healthy Nation ](/kenya/health/healthy-nation)
* [ Talking Point ](/kenya/health/talking-point)
* [ Emergency Contacts ](/kenya/health/emergency-contacts)
* More
[ Search ](/kenya/search)
* [ News ](/kenya/news)
* [ World ](/kenya/news/world)
* [ Gender ](/kenya/news/gender)
* [ Tech ](/kenya/news/tech)
* [ Counties ](/kenya/counties)
* [ Nairobi Metro ](/kenya/counties/nairobi-metro)
* [ Coast ](/kenya/counties/coast)
* [ Mountain ](/kenya/counties/mountain)
* [ Lake Region ](/kenya/counties/lake-region)
* [ Rift Valley ](/kenya/counties/rift-valley)
* [ Northern ](/kenya/counties/northern)
* [ Business ](/kenya/business)
* [ Companies ](/kenya/business/companies)
* [ Finance and Markets ](/kenya/business/finance-and-markets)
* [ Seeds of Gold ](/kenya/business/seeds-of-gold)
* [ Enterprise ](/kenya/business/enterprise)
* [ Opinion ](/kenya/blogs-opinion)
* [ Editorials ](/kenya/blogs-opinion/editorials)
* [ Our Columnists ](/kenya/blogs-opinion/opinion)
* [ Guest Blogs ](/kenya/blogs-opinion/blogs)
* [ Letters to the Editor ](/kenya/blogs-opinion/letters)
* [ Cutting Edge ](/kenya/blogs-opinion/cutting-edge)
* [ Cartoons ](/kenya/blogs-opinion/cartoons)
* [ Sports ](/kenya/sports)
* [ Motorsport ](/kenya/sports/motorsports)
* [ Football ](/kenya/sports/football)
* [ Athletics ](/kenya/sports/athletics)
* [ Rugby ](/kenya/sports/rugby)
* [ TalkUP! ](/kenya/sports/talkup)
* [ Other Sports ](/kenya/sports/other-sports)
* [ Life & Style ](/kenya/life-and-style)
* [ MyNetwork ](/kenya/life-and-style/mynetwork)
* [ Culture ](/kenya/life-and-style/culture)
* [ Family ](/kenya/life-and-style/family)
* [ Relationships ](/kenya/life-and-style/relationships)
* [ Art & Books ](/kenya/life-and-style/art-books)
* [ Travel ](/kenya/life-and-style/travel)
* [ Wellness ](/kenya/life-and-style/wellness)
* [ Health ](/kenya/health)
* [ Healthy Nation ](/kenya/health/healthy-nation)
* [ Talking Point ](/kenya/health/talking-point)
* [ Emergency Contacts ](/kenya/health/emergency-contacts)
* [ Podcasts ](/kenya/audio)
* [ Puzzles ](/kenya/puzzles)
* ## Editions
* [ Africa ](https://nation.africa/africa)
* [ Kenya ](/kenya)
* [ Uganda ](https://www.monitor.co.ug/uganda)
* [ Mwananchi ](https://www.mwananchi.co.tz/mw)
* * * *
## ePaper
* [ Daily Nation ](https://epaper.nation.africa/ke)
* [ Daily Monitor ](https://epaper.nation.africa/ug)
* [ The Citizen ](https://epaper.nation.africa/tz)
* [ Play Store ](https://play.google.com/store/apps/developer?id=Nation+Media+Group&hl=en&gl=US)
* [ App Store ](https://apps.apple.com/us/developer/nation-media-group-ltd/id771736086)
# Causes of memory loss in your 20s and 30s
Monday, May 02, 2022
Poor sleeping habits can cause considerable memory loss and forgetfulness even
in young people.
Photo credit: Poor sleeping habits can cause considerable memory loss and
forgetfulness even in young people.
[ ](/kenya/health/men-s-health/denis-mutua-3539436)
By [ Denis Mutua ](/kenya/health/men-s-health/denis-mutua-3539436)
## What you need to know:
* Studies have shown that the gradual decline of memory starts in the 20s but becomes noticeable in sunset years.
* Noticeable forgetfulness in young people is a sign that something is amiss.
* Eating well, remaining physically active, adequate sleep and rest can help you avoid memory loss.
## Thank you for reading Nation.Africa
[ Show plans ](/kenya/subscribe)
Once in a while, everybody forgets where they placed their keys or what they
were going to do in the kitchen. However, if you are in your 20s and you’re
forgetting things too often, including important details of events in your
life, you may be experiencing memory loss.
While memory loss in older people is expected, in young people, it is a cause
for concern. It could be a symptom of an unhealthy lifestyle or an underlying
medical condition, either of which needs to be diagnosed and managed.
Here are four possible causes of memory loss and what you can do about it:
## How is your sleep?
The brain rejuvenates itself while you sleep. In more detailed studies,
scientists observed brain waves believed to transfer memories to the
prefrontal cortex for long-term storage.
Inadequate sleep interrupts this process leading to loss of long-term memory.
If this persists for an extended period, short-term memory is also affected.
Poor sleeping habits therefore can cause considerable memory loss and
forgetfulness even in young people. Although a lot of focus is put on how long
you sleep, the quality also matters. Eight hours of interrupted and
uncomfortable sleep will not be beneficial.
Assess your sleeping habits and change anything that could be causing poor
sleep. For example, avoid caffeine and using the Internet just before going to
bed.
If the sleeplessness or poor sleep persists even after changing your
lifestyle, seek medical assistance.
## The mental health connection
Illnesses and conditions such as depression, anxiety, and stress can lead to
short-term memory loss. The effect of mental illnesses on memory can have a
far-reaching impact on your day-to-day activities. Left untreated, it can
affect long-term memory as well.
For instance, as a young adult, your day probably involves studies and job
tasks that rely on memory. Poor memory can lead to poor performance and low
productivity in your studies and the workplace. This can get worse if you
consider other negative effects of mental illnesses such as poor
concentration, lack of clarity of thoughts, and consequently, poor decision-
making.
If you are suffering from chronic stress, depression, anxiety, or other
similar conditions, seek medical attention promptly to keep the condition from
getting worse. Make sure you mention the memory loss to the health
professional because some antidepressants can cause or exacerbate memory loss.
## Medications
Some medications can cause memory loss. Usually, this is a concern among older
people taking different types of medications for pain, to help with sleeping,
or for cognitive illnesses. However, some drugs such as antidepressants, anti-
anxiety medication, mood-stabilizers/tranquilizers, opiate pain relievers, and
some cholesterol-lowering drugs can also affect young people.
Usually, such memory loss is mild, and only for the period, you are under the
medication. However, if the memory loss gets to the point where you and other
people can notice it, then it is a serious case. Communicate this with your
pharmacist if you bought the medication over the counter, or with the
physician if it was a prescription drug. They will help you not only identify
the exact medication that’s causing the memory loss but also offer you
alternatives.
## Excessive intake of alcohol, cigarettes, and drugs
You’ve probably had a night out where you or your friend blacked out after
taking alcohol. Such memory loss can happen even if you didn’t black out
fully. Some people struggle to recall what they did, or even who they were
with.
Such people may be diagnosed with alcohol use disorder. If they persist to
drink often, it starts to affect both short-term and long-term memories.
Smoking cigarettes and other substances also affect your brain’s ability to
remember mainly by limiting the oxygen supply. As with other causes, this also
starts by impacting short-term memory.
Most narcotics cause hallucinations and other-worldly experiences.
Unfortunately, the same components that cause you to feel excited or relaxed
tamper with your young brain to an extent that you start losing your memory.
Previous article [
### The essential manual for making friends at your new school
](/kenya/health/tips/the-essential-manual-for-making-friends-at-your-new-
school-3574420)
Next article [
### The complete guide to understanding and managing asthma
](/kenya/health/tips/the-complete-guide-to-understanding-and-managing-
asthma-3574328)
* [ ](https://www.facebook.com/sharer/sharer.php?u=https://nation.africa/kenya/health/tips/causes-of-memory-loss-in-your-20s-and-30s-3596324)
* [ ](https://twitter.com/intent/tweet?text=Causes%20of%20memory%20loss%20in%20your%2020s%20%20and%2030s&url=https://nation.africa/kenya/health/tips/causes-of-memory-loss-in-your-20s-and-30s-3596324)
* [ ](https://wa.me/?text=https://nation.africa/kenya/health/tips/causes-of-memory-loss-in-your-20s-and-30s-3596324)
* [ ](/cdn-cgi/l/email-protection#d7e8a4a2b5bdb2b4a3ea94b6a2a4b2a4f7b8b1f7bab2bab8a5aef7bbb8a4a4f7beb9f7aeb8a2a5f7e5e7a4f7b6b9b3f7e4e7a4f1b5b8b3aeeabfa3a3a7a4edf8f8b9b6a3beb8b9f9b6b1a5beb4b6f8bcb2b9aeb6f8bfb2b6bba3bff8a3bea7a4f8b4b6a2a4b2a4fab8b1fabab2bab8a5aefabbb8a4a4fabeb9faaeb8a2a5fae5e7a4fab6b9b3fae4e7a4fae4e2eee1e4e5e3)
Please enable JavaScript to view the [ comments powered by Disqus.
](https://disqus.com/?ref_noscript)
### Join the discussion
Login with your Nation account [ Commenting as **** Please add your name to
your Nation profile to comment ](/kenya/account)
## Editor's picks
* [
### How to bridge social chasms as an introvert
On social media, you can find people and groups with similar interests or
hobbies.
Tips May 02, 2022 ](/kenya/health/tips/how-to-bridge-social-chasms-as-an-
introvert-3577246)
* [
### Everything you need to know about autism and how to support your child
According to the CDC, diagnosing a child with autism can be a lengthy and
difficult process.
Tips May 09, 2022 ](/kenya/health/tips/everything-you-need-to-know-about-
autism-and-how-to-support-your-child-3572452)
## [ In the headlines ](/kenya)
* [ News ](/kenya/news)
* [ Counties ](/kenya/counties)
* [ Business ](/kenya/business)
* [ Opinion ](/kenya/blogs-opinion)
* [ Sports ](/kenya/sports)
* [ Life & Style ](/kenya/life-and-style)
* [ Health ](/kenya/health)
* [ Podcasts ](/kenya/audio)
* [ Puzzles ](/kenya/puzzles)
* [
### Revealed: Maai Mahiu tragedy was caused by man-made gulley
Raging waters also destroyed part of the Nairobi-Nakuru railway line.
Nakuru 8 hours ago ](/kenya/counties/nakuru/revealed-inside-man-made-gulley-
near-railway-that-caused-maai-mahiu-tragedy-4607338)
* [
### Maai Mahiu tragedy: Death toll rises to 46
Police say most of the dead were women, children and elderly people who
probably could not run fast enough.
Nakuru 8 hours ago ](/kenya/counties/nakuru/maai-mahiu-tragedy-death-toll-
rises-to-45-4606978)
* [
### CS Murkomen dispatches NYS officers to site of Maai Mahiu tragedy
He also revealed that 300 people have died so far due to flooding.
Nakuru 8 hours ago ](/kenya/counties/nakuru/cs-murkomen-dispatches-nys-
officers-to-site-of-maai-mahiu-tragedy-4607274)
* * *
# Oops
## We're sorry, we couldn't load the article
If you have an Ad-blocker please disable it and reload the page or try again
later.
Reload page
* [ News ](/kenya/news)
* [ World ](/kenya/news/world)
* [ Gender ](/kenya/news/gender)
* [ Tech ](/kenya/news/tech)
* [ Counties ](/kenya/counties)
* [ Nairobi Metro ](/kenya/counties/nairobi-metro)
* [ Coast ](/kenya/counties/coast)
* [ Mountain ](/kenya/counties/mountain)
* [ Lake Region ](/kenya/counties/lake-region)
* [ Rift Valley ](/kenya/counties/rift-valley)
* [ Northern ](/kenya/counties/northern)
* [ Business ](/kenya/business)
* [ Companies ](/kenya/business/companies)
* [ Finance and Markets ](/kenya/business/finance-and-markets)
* [ Seeds of Gold ](/kenya/business/seeds-of-gold)
* [ Enterprise ](/kenya/business/enterprise)
* [ Opinion ](/kenya/blogs-opinion)
* [ Editorials ](/kenya/blogs-opinion/editorials)
* [ Our Columnists ](/kenya/blogs-opinion/opinion)
* [ Guest Blogs ](/kenya/blogs-opinion/blogs)
* [ Letters to the Editor ](/kenya/blogs-opinion/letters)
* [ Cutting Edge ](/kenya/blogs-opinion/cutting-edge)
* [ Cartoons ](/kenya/blogs-opinion/cartoons)
* [ Sports ](/kenya/sports)
* [ Motorsport ](/kenya/sports/motorsports)
* [ Football ](/kenya/sports/football)
* [ Athletics ](/kenya/sports/athletics)
* [ Rugby ](/kenya/sports/rugby)
* [ TalkUP! ](/kenya/sports/talkup)
* [ Other Sports ](/kenya/sports/other-sports)
* [ Life & Style ](/kenya/life-and-style)
* [ MyNetwork ](/kenya/life-and-style/mynetwork)
* [ Culture ](/kenya/life-and-style/culture)
* [ Family ](/kenya/life-and-style/family)
* [ Relationships ](/kenya/life-and-style/relationships)
* [ Art & Books ](/kenya/life-and-style/art-books)
* [ Travel ](/kenya/life-and-style/travel)
* [ Wellness ](/kenya/life-and-style/wellness)
* [ Health ](/kenya/health)
* [ Healthy Nation ](/kenya/health/healthy-nation)
* [ Talking Point ](/kenya/health/talking-point)
* [ Emergency Contacts ](/kenya/health/emergency-contacts)
* [ Podcasts ](/kenya/audio)
* [ Puzzles ](/kenya/puzzles)
* [ Empower Africa ](/kenya/empower)
* [ Contact Us ](/kenya/contact-us-294088)
* [ Frequently asked questions ](/kenya/frequently-asked-questions-303716)
* [ NMG Privacy Policy ](/kenya/nmg-privacy-policy-303724)
* [ Terms and Conditions of Use ](/kenya/terms-and-conditions)
* [ Movies ](https://kenyabuzz.com/movies)
* [ Events ](https://kenyabuzz.com/events)
Nation Media Group © 2024
| biology | 865806 | https://da.wikipedia.org/wiki/Emergens | Emergens | Indenfor filosofi, systemteori, videnskab og kunst er emergens processen hvorved større entiteter, helheder, mønstre og regulariteter opstår gennem vekselvirkning mellem mindre eller simplere entiteter, selvom disse ikke selv udviser eller besidder sådanne egenskaber.
Emergens er central i teorier af integrationsniveauer og af komplekse systemer. Fx bliver fænomenet liv studeret i biologi almindeligvis opfatter som et emergent egenskab af interagerende molekyler, som studeres i kemi - og molekylers fænomener skyldes interaktioner mellem elementarpartikler, som igen modelleres i partikelfysik. Neurobiologiske fænomener bliver ofte opfattet som grundlag for psykologiske fænomener, som økonomiske fænomener derfor baserer sig på.
Indenfor filosofi refererer emergens typisk til emergentisme. Næsten alle former for emergentisme omfatter en form for epistemisk eller ontologisk irreducibilitet til de lavere niveauer.
Definitioner
Ideen om emergens har eksisteret siden i hvert fald Aristoteles.
John Stuart Mill
og Julian Huxley
er to af mange videnskabsfolk og filosoffer, som har skrevet om begrebet.
Termen "emergens" blev navngivet af filosoffen G. H. Lewes, som skrev:
"Every resultant is either a sum or a difference of the co-operant forces; their sum, when their directions are the same -- their difference, when their directions are contrary. Further, every resultant is clearly traceable in its components, because these are homogeneous and commensurable. It is otherwise with emergents, when, instead of adding measurable motion to measurable motion, or things of one kind to other individuals of their kind, there is a co-operation of things of unlike kinds. The emergent is unlike its components insofar as these are incommensurable, and it cannot be reduced to their sum or their difference."
Økonomen Jeffrey Goldstein gav den nuværende definition af emergens i tidskriftet Emergence.
Goldstein definerede oprindeligt emergens som: "the arising of novel and coherent structures, patterns and properties during the process of self-organization in complex systems".
Goldstein's definition kan yderligere udvide detajleringsgraden i beskrivelsen:
"The common characteristics are: (1) radical novelty (features not previously observed in systems); (2) coherence or correlation (meaning integrated wholes that maintain themselves over some period of time); (3) A global or macro "level" (i.e. there is some property of "wholeness"); (4) it is the product of a dynamical process (it evolves); and (5) it is "ostensive" (it can be perceived)." For good measure, Goldstein throws in supervenience.
System videnskabsmanden Peter Corning siger at levende systemer ikke kan reduceres til de underliggende fysiklove:
Rules, or laws, have no causal efficacy; they do not in fact “generate” anything. They serve merely to describe regularities and consistent relationships in nature. These patterns may be very illuminating and important, but the underlying causal agencies must be separately specified (though often they are not). But that aside, the game of chess illustrates ... why any laws or rules of emergence and evolution are insufficient. Even in a chess game, you cannot use the rules to predict “history” — i.e., the course of any given game. Indeed, you cannot even reliably predict the next move in a chess game. Why? Because the “system” involves more than the rules of the game. It also includes the players and their unfolding, moment-by-moment decisions among a very large number of available options at each choice point. The game of chess is inescapably historical, even though it is also constrained and shaped by a set of rules, not to mention the laws of physics. Moreover, and this is a key point, the game of chess is also shaped by teleonomic, cybernetic, feedback-driven influences. It is not simply a self-ordered process; it involves an organized, “purposeful” activity.
Se også
Kilder/referencer
Bibliografi
Yderligere læsning
Alexander, V. N. (2011). The Biologist’s Mistress: Rethinking Self-Organization in Art, Literature and Nature. Litchfield Park AZ: Emergent Publications.
Bedau, Mark A. (1997)."Weak Emergence" .
Blitz, David. (1992). Emergent Evolution: Qualitative Novelty and the Levels of Reality. Dordrecht: Kluwer Academic.
Chalmers, David J. (2002). "Strong and Weak Emergence" http://consc.net/papers/emergence.pdf Republished in P. Clayton and P. Davies, eds. (2006) The Re-Emergence of Emergence. Oxford: Oxford University Press.
Philip Clayton (2005). Mind and Emergence: From Quantum to Consciousness Oxford: OUP,
Philip Clayton & Paul Davies (eds.) (2006). The Re-Emergence of Emergence: The Emergentist Hypothesis from Science to Religion Oxford: Oxford University Press.
Corning, Peter A. (2005). "Holistic Darwinism: Synergy, Cybernetics and the Bioeconomics of Evolution." Chicago: University of Chicago Press.
Felipe Cucker and Stephen Smale (2007), The Japanese Journal of Mathematics, The Mathematics of Emergence
*
Haag, James W. (2008). Emergent Freedom: Naturalizing Free Will Goettingen: Vandenhoeck & Ruprecht,
Holman, Peggy. (2010). Engaging Emergence: Turning upheaval into opportunity. San Francisco: Barrett-Koehler.
Hopper, P. 1998. Emergent Grammar. In: Tomasello, M. eds. 1998. The new psychology of language: Cognitive and functional approaches to language structure. Mahwah, NJ: Earlbaum, pp. 155–176.
Ignazio Licata & Ammar Sakaji (eds) (2008). Physics of Emergence and Organization , , World Scientific and Imperial College Press.
Jackie (Jianhong) Shen (2008), Cucker–Smale Flocking Emergence under Hierarchical Leadership In: SIAM J. Applied Math., 68:3,
Solé, Ricard and Goodwin, Brian (2000) Signs of life: how complexity pervades biology, Basic Books, New York.
Eksterne henvisninger
The Emergent Universe : An interactive introduction to emergent phenomena, from ant colonies to Alzheimer's.
Exploring Emergence : An introduction to emergence using CA and Conway's Game of Life from the MIT Media Lab
ISCE group : Institute for the Study of Coherence and Emergence.
Towards modeling of emergence : lecture slides from Helsinki University of Technology
Biomimetic Architecture - Emergence applied to building and construction | danish | 0.871458 |
baby_memories/howdoyouusememorytec.txt | ` `
Agree & Join LinkedIn
By clicking Continue to join or sign in, you agree to LinkedIn’s [ User
Agreement ](/legal/user-agreement?trk=linkedin-tc_auth-button_user-agreement)
, [ Privacy Policy ](/legal/privacy-policy?trk=linkedin-tc_auth-
button_privacy-policy) , and [ Cookie Policy ](/legal/cookie-
policy?trk=linkedin-tc_auth-button_cookie-policy) .
` ` ` ` ` ` ` `
` ` ` ` ` ` ` ` ` ` ` `
Skip to main content [ LinkedIn ](/?trk=article-ssr-frontend-x-article_nav-
header-logo)
* [ Articles ](https://www.linkedin.com/pulse/topics/home/?trk=article-ssr-frontend-x-article_guest_nav_menu_articles)
* [ People ](https://www.linkedin.com/pub/dir/+/+?trk=article-ssr-frontend-x-article_guest_nav_menu_people)
* [ Learning ](https://www.linkedin.com/learning/search?trk=article-ssr-frontend-x-article_guest_nav_menu_learning)
* [ Jobs ](https://www.linkedin.com/jobs/search?trk=article-ssr-frontend-x-article_guest_nav_menu_jobs)
[ Join now ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_nav-header-join) [ Sign in
](https://www.linkedin.com/uas/login?session_redirect=%2Fadvice%2F0%2Fhow-do-
you-use-memory-techniques-recall-retain&fromSignIn=true&trk=article-ssr-
frontend-x-article_nav-header-signin) [
](https://www.linkedin.com/uas/login?session_redirect=%2Fadvice%2F0%2Fhow-do-
you-use-memory-techniques-recall-retain&fromSignIn=true&trk=article-ssr-
frontend-x-article_nav-header-signin)
` ` ` ` ` ` ` `
1. [ All ](https://www.linkedin.com/pulse/topics/home/)
2. [ Soft Skills ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/)
3. [ Time Management ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/time-management-s2263/)
# How do you use memory techniques to recall and retain information better?
Powered by AI and the LinkedIn community
### 1
What are memory techniques?
### 2
How to choose the right memory technique?
### 3
How to use association and visualization?
### 4
How to use mnemonics and chunking?
### 5
How to use repetition?
Be the first to add your personal experience
### 6
Here’s what else to consider
Do you struggle to remember important information for your work or studies? Do
you wish you could improve your focus and concentration while learning new
skills? If so, you might benefit from using some memory techniques that can
help you recall and retain information better. In this article, we will
explore some of the most effective memory techniques and how to apply them in
different situations.
` `
Top experts in this article
Selected by the community from 13 contributions. [ Learn more
](https://www.linkedin.com/help/linkedin/answer/a1652832)
Earn a Community Top Voice badge
Add to collaborative articles to get recognized for your expertise on your
profile. [ Learn more
](https://www.linkedin.com/help/linkedin/answer/a1413111)
Start a contribution
* [ AJ Johnson AVP, Branch Manager & Next Step Elite Manager at Regions Bank ](https://www.linkedin.com/in/aj-johnson-291208206?trk=article-ssr-frontend-x-article)
View contribution ` ` ` `
12
` ` ` ` ` ` ` ` ` ` ` ` ` `
* [ Dr Adnan Ali As a business owner, I understand the stress and overwhelm you're having with your business and personal goals. I help… ](https://uk.linkedin.com/in/dradnanali?trk=article-ssr-frontend-x-article)
View contribution ` ` ` `
10
` ` ` ` ` ` ` ` ` ` ` ` ` `
* [ Parul Sood General Manager @ Zydus Group | Gastroenterology, Hepatology | Linkedin #TopVoice ](https://in.linkedin.com/in/parulsood7?trk=article-ssr-frontend-x-article)
View contribution ` ` ` `
6
` ` ` ` ` ` ` ` ` ` ` ` ` `
See what others are saying
` `
## 1 What are memory techniques?
Memory techniques are strategies that can help you encode, store, and recall
information more proficiently. They can be used to increase your learning,
creativity, and productivity by making the data more meaningful, memorable,
and manageable. Association is one such technique that involves connecting new
knowledge to something you’re already familiar with, such as pictures, words,
or emotions. Visualization is another method in which you create vivid mental
images of the information you want to remember. Mnemonics use acronyms,
rhymes, or phrases to remember a list or sequence of facts, such as ROYGBIV
for the colors of the rainbow. Chunking breaks down large or complex
information into smaller groups or units like phone numbers or dates.
Repetition is an important tool in memory techniques; it involves reviewing
and rehearsing the information regularly and in different ways.
` ` ` ` ` `
[ Add your perspective ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article)
` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` `
Help others by sharing more (125 characters min.) Cancel
Add Save
* [ AJ Johnson
AVP, Branch Manager & Next Step Elite Manager at Regions Bank
](https://www.linkedin.com/in/aj-johnson-291208206?trk=article-ssr-frontend-x-
article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
As we write down notes, our eyes take in the information and images are stored
in our brain. If we read aloud as we write then our brain stores the audio,
which can then be easily recalled with repetition.
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
12
` ` ` ` ` ` ` ` ` ` ` ` ` `
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
* [ Parul Sood
General Manager @ Zydus Group | Gastroenterology, Hepatology | Linkedin
#TopVoice
](https://in.linkedin.com/in/parulsood7?trk=article-ssr-frontend-x-article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
Acronyms work best for me . I’m sure they helped all of us memorise the basics
…like colours of the rainbow (VIBGYOR) or the planets of the solar system .
Even now I often use acronyms to memorise important points at work
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
6
` ` ` ` ` ` ` ` ` ` ` ` ` `
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
* [ John Santana
3D Artist for Games | Unity Awards Winner, Learning through helping others.
](https://ca.linkedin.com/in/j-santana3d?trk=article-ssr-frontend-x-article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
Well something that I’ve realized is how important is to do constant recall of
the information you learn, always try to use it. Otherwise your brain just
will take out that information, keep in mind that a way to keep a healthy
mental health learning and being exposed to constant learning can help to
improve memory, recall and retention.
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
* [ MAINAK CHAKRABORTY
GENERAL MANAGER : SALES MARKETING & OPERATIONS || INDIA BUSINESS || CRITICAL
CARE || HOSPITAL BUSINESS
](https://in.linkedin.com/in/mainak-chakraborty-90b0a238?trk=article-ssr-
frontend-x-article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
I always try to use unique techniques which can be remembered easily . For eg
: It was during one of the team meeting of west zone ( earstwhile Ranbaxy
legacy Sun pharmaceutical ) wherein I was to be introduced to the team as west
zone new Zonal Head. ( transferred from Kolkata) . While introducing I could
make out that maximum colleagues were not able to understand ,rather couldn't
pronounce my name correctly ( MAINAK ). Hence to make it easy I asked the team
to say "My" & next to say "NAK" ( meaning nose in hindi) & to pronouce both at
a time... They all literally shouted - MYNAK... That's exactly sounds my name
( though spelling is different) but everyone grabbed it easily & never forgot
my name pronouncing as MYNAK ( MAINAK)..
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
* [ Nim Nadarajah, C.CISO, PMP, MBA, SSGB, CSM
C.CISO, Cyber Security, Compliance & Transformation Expert | Executive Board
Member | Keynote Speaker | Podcast Guest | 🥇 Top 100 Leaders in Canada 2023
](https://ca.linkedin.com/in/nimitinnovation?trk=article-ssr-frontend-x-
article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
One thing I have always found helpful is to acknowledge when I’m receiving.
Hi, my name is Nim. Hi Nim. It’s nice to meet you. Verbalizing during audible
learning is an excellent way to write from short term memory to long term
memory. They other way I hack memory In visual meetings is re-writing and re-
stating. I will make a statement to affirm my understanding and link it to a
follow up question. Small hacks from the trenches but works great for me! Have
you tried these ?
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
` ` ` `
## 2 How to choose the right memory technique?
When it comes to memory techniques, there is no one-size-fits-all approach.
Consider your learning style, goals, and the type and amount of information
you want to remember. Experiment with different techniques and combine or
modify them to best suit your preferences and needs. For abstract or
conceptual information, use association and visualization; for factual or
sequential information, use mnemonics and chunking; for procedural or skill-
based information, use repetition. Additionally, for creative or problem-
solving tasks, employ association and visualization; for recall or recognition
tasks, try mnemonics and chunking; for retention or application tasks, rely on
repetition.
` ` ` ` ` `
[ Add your perspective ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article)
` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` `
Help others by sharing more (125 characters min.) Cancel
Add Save
* [ Josue V.
Strategic HR (for) Growth-mode Administration (yielding) Operational
Excellence (and reliable) Executive Support
](https://www.linkedin.com/in/josuevw?trk=article-ssr-frontend-x-article)
(edited)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
In my experience, I have found this advantageous: do not be afraid to
“download” the information to the memory technique. -If you store it in a
memory mansion, let it live there. You can visit when needed. -If you have an
acronym or true mnemonic word or phrase, enjoy the freedom of letting the
information hide in that safe and accessible space. Don’t worry about
forgetting the info. You built the safe. You built the memory technique. Don’t
work to remember everything. Download it and let the memory technique work for
you!
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
4
` ` ` ` ` ` ` ` ` ` ` ` ` `
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
` ` ` `
## 3 How to use association and visualization?
Association and visualization are effective memory techniques that can help
you remember information that is otherwise hard to recall or relate to. They
create connections between the new information and something familiar,
relevant, or emotional to you. To use them effectively, select a cue or
trigger that is easy to remember and associate with the information, such as a
word, image, sound, smell, or feeling. Make the association as strong,
specific, and meaningful as possible by using your senses, emotions, and
imagination. Additionally, review and reinforce the association regularly and
in different contexts by recalling the cue and the information together and
visualizing them in your mind.
` ` ` ` ` `
[ Add your perspective ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article)
` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` `
Help others by sharing more (125 characters min.) Cancel
Add Save
* [ Karen Spears
Lettering Artist, Brand Architect, Mind-Mapper, Creative Director | Founder at
Kareracter
](https://www.linkedin.com/in/karennspears?trk=article-ssr-frontend-x-article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
Mind-Mapping is a powerful visualization tool that I leverage in creative
problem solving. It’s really an effective tool for entrepreneurs or creative
workers to expand their realm of ideas starting with just a pen, paper, and
curiosity.
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
4
` ` ` ` ` ` ` ` ` ` ` ` ` `
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
` ` ` `
## 4 How to use mnemonics and chunking?
Mnemonics and chunking are effective memory techniques that can help you
remember information that is difficult to organize or recall. To use them, you
need to determine the key information you want to remember and arrange it in a
logical order or pattern. Then, create a mnemonic device such as an acronym,
rhyme, phrase, or story using the first letters or sounds of the information.
Additionally, form chunks of 3 to 7 items with commonality or significance to
you. Lastly, review and practice the mnemonic device and the chunks regularly
and in different ways such as reciting them aloud, writing them down, or
quizzing yourself.
` ` ` ` ` `
[ Add your perspective ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article)
` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` `
Help others by sharing more (125 characters min.) Cancel
Add Save
* [ Laurie Mixter
Sales and E-Comerace
](https://www.linkedin.com/in/laurie-mixter-96292b107?trk=article-ssr-
frontend-x-article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
\- I remember parts of what I need to remember! \- I take down information on
sticky notes! \- I send myself emails and put them in Tasks on Google!
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
6
` ` ` ` ` ` ` ` ` ` ` ` ` `
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
` ` ` `
## 5 How to use repetition?
Repetition is a powerful memory technique that can help you remember
information that is otherwise hard to retain or apply. It works by
strengthening the neural pathways in your brain that store the information. To
get the most out of repetition, you should review the information soon after
learning it, and at regular intervals thereafter. Additionally, use a variety
of methods and formats to review the information, such as reading, writing,
speaking, listening, or testing yourself. Furthermore, use spaced repetition
to optimize your review sessions. This involves reviewing the information at
increasing time intervals depending on how well you remember it; for instance,
you could review the information after 10 minutes, then after one hour, then
after one day, then after one week, and so on.
` ` ` ` ` `
[ Add your perspective ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article)
` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` `
Help others by sharing more (125 characters min.) Cancel
Add Save
` ` ` `
## 6 Here’s what else to consider
This is a space to share examples, stories, or insights that don’t fit into
any of the previous sections. What else would you like to add?
` ` ` ` ` `
[ Add your perspective ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article)
` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` ` `
Help others by sharing more (125 characters min.) Cancel
Add Save
* [ Dr Adnan Ali
As a business owner, I understand the stress and overwhelm you're having with
your business and personal goals. I help you to take back control of your
happiness, health and wealth.
](https://uk.linkedin.com/in/dradnanali?trk=article-ssr-frontend-x-article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
One of my all time favourites for improving memory and retaining information
is through a study technique named ‘blurting’. Literally everything you know
about a topic or subject being blurted on to a piece of paper, and then added
to through use of a resource. This technique can also be used to help you
remember to do things. For example, at the start of a day/week/month jotting
down everything you can think of that you need to do, and then using that list
to build out your calendar schedule.
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
10
` ` ` ` ` ` ` ` ` ` ` ` ` `
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
* [ Catherine Beers
Self-motivated Client Service Representative, Real Estate Broker Associate
](https://www.linkedin.com/in/catherinegbeers?trk=article-ssr-frontend-x-
article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
One thing that's always helped me is Mnemonics. For example in California,
property taxes are due 2x/year. No Darn Fooling Around. NDFA. The first half
is due in November past due December. The second half is due February past due
in April.
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
1
` ` ` ` ` ` ` ` ` ` ` ` ` `
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
* [ Sarah Irwin
Business Attorney
](https://www.linkedin.com/in/sarah-irwin-00ab0950?trk=article-ssr-frontend-x-
article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
One of the best tools for me to understand information is flowcharts. Find an
app and use it to make connections that aren’t as clear in basic written word.
For example, I use flow charts to delineate relations between corporate
entities when dealing with complex corporate legal issues. Creating the flow
chart helps me understand the relationships and seeing the completed chart
helps me remember those relationships.
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
1
` ` ` ` ` ` ` ` ` ` ` ` ` `
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
* [ Har-el E.
Inflight Product Purchasing Coordinator at Sunwing
](https://ca.linkedin.com/in/har-el-eizenshtein?trk=article-ssr-frontend-x-
article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
What I've done while studying throughout high school and university is to
record myself narrating important concepts using a microphone app when
reviewing them, and then playing them back to myself while engaging in a short
power nap. By employing this practice, I lower my level of activity, but
maintain my focus and thus my ability to reinforce what I had learned via
listening to my own voice recording. I feel this maximizes my time management
as more memory retention can be achieved in a shorter period of time than just
conventional review.
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
* [ John Santana
3D Artist for Games | Unity Awards Winner, Learning through helping others.
](https://ca.linkedin.com/in/j-santana3d?trk=article-ssr-frontend-x-article)
* Copy link to contribution
* [ Report contribution ](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-retain&trk=comment-semaphore-sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE_CONTRIBUTION&_f=guest-reporting)
Thanks for letting us know! You'll no longer see this contribution
` ` ` ` ` `
Fascinating idea! I sometimes do this too when I need to deal with a hard
choice, I just write down all the information to be able to see all better and
have a broad perspective of all the elements of each of the possible choices,
…see more
` `
[ Like ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_contribution-social-activity_like-
cta)
Like
Celebrate
Support
Love
Insightful
Funny
[ Unhelpful ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain)
` `
[ Time Management ](https://www.linkedin.com/showcase/skills-time-
management/?trk=article-ssr-frontend-x-article_publisher-author-card)
### Time Management
[ \+ Follow ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article_publisher-author-card)
## Rate this article
We created this article with the help of AI. What do you think of it?
[ It’s great ](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article) [ It’s not so great
](https://www.linkedin.com/signup/cold-
join?session_redirect=%2Fadvice%2F0%2Fhow-do-you-use-memory-techniques-recall-
retain&trk=article-ssr-frontend-x-article)
## Thanks for your feedback
Your feedback is private. Like or react to bring the conversation to your
network.
` ` ` ` ` `
## Tell us more
Tell us why you didn’t like this article.
* It’s not on a professional topic
* It contains inaccuracies
* It has offensive language
* It has harmful advice
* It contains stereotypes or bias
* It’s redundant and unclear
* Translation quality is poor
* It’s not relevant in my country, region or culture
If you think something in this article goes against our [ Professional
Community Policies ](https://www.linkedin.com/legal/professional-community-
policies) , please let us know.
[ Report this article ](/uas/login?trk=article_quality_feedback-sign-in-
redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE&_f=guest-
reporting)
We appreciate you letting us know. Though we’re unable to respond directly,
your feedback helps us improve this experience for everyone.
If you think this goes against our [ Professional Community Policies
](https://www.linkedin.com/legal/professional-community-policies) , please let
us know.
[ Report this article ](/uas/login?trk=article_quality_feedback-sign-in-
redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE&_f=guest-
reporting)
Cancel Submit Done
[ Report this article
](/uas/login?session_redirect=https%3A%2F%2Fwww.linkedin.com%2Fadvice%2F0%2Fhow-
do-you-use-memory-techniques-recall-retain&trk=article-ssr-frontend-x-article-
sign-in-redirect&guestReportContentType=AUTO_GENERATED_SKILL_ARTICLE&_f=guest-
reporting)
## More articles on Time Management
No more previous content
* [
Here's how you can enhance teamwork and collaboration with conflict resolution
skills.
2 contributions
](https://www.linkedin.com/advice/0/heres-how-you-can-enhance-teamwork-
collaboration-taldf)
* [
Here's how you can navigate interview questions without feeling rushed.
1 contribution
](https://www.linkedin.com/advice/0/heres-how-you-can-navigate-interview-
questions-iesuc)
* [
Here's how you can maintain focus and manage your time by avoiding
distractions as an employee.
2 contributions
](https://www.linkedin.com/advice/1/heres-how-you-can-maintain-focus-manage-
your-time-ni9ee)
* [
Here's how you can effectively manage stress and pressure in the workplace as
an entry-level professional.
2 contributions
](https://www.linkedin.com/advice/1/heres-how-you-can-effectively-manage-
stress-pressure-bmgec)
* [
Here's how you can identify tasks that are appropriate for delegation.
5 contributions
](https://www.linkedin.com/advice/0/heres-how-you-can-identify-tasks-
appropriate-delegation-tn14e)
* [
Here's how you can handle a low salary offer during a negotiation.
1 contribution
](https://www.linkedin.com/advice/0/heres-how-you-can-handle-low-salary-offer-
during-vbr0e)
* [
Here's how you can achieve work-life balance through delegation.
2 contributions
](https://www.linkedin.com/advice/0/heres-how-you-can-achieve-work-life-
balance-through-sinjf)
* [
Here's how you can effectively prioritize tasks and deadlines within a team.
6 contributions
](https://www.linkedin.com/advice/0/heres-how-you-can-effectively-prioritize-
tasks-wm8if)
* [
Here's how you can balance client work and administrative tasks as a self-
employed individual.
](https://www.linkedin.com/advice/0/heres-how-you-can-balance-client-work-
administrative-vesxe)
No more next content
[ See all ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/time-
management-s2263/?trk=article-ssr-frontend-x-article)
` `
## Explore Other Skills
* [ Communication ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/communication-s135/)
* [ Interpersonal Skills ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/interpersonal-skills-s8399/)
* [ Public Speaking ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/public-speaking-s1101/)
* [ Personal Branding ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/personal-branding-s6796/)
* [ Leadership Development ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/leadership-development-s759/)
* [ Thought Leadership ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/thought-leadership-s3688/)
* [ Critical Thinking ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/critical-thinking-s4392/)
* [ Leadership ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/leadership-s154/)
* [ Research Skills ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/research-skills-s176/)
* [ Executive Coaching ](https://www.linkedin.com/pulse/topics/soft-skills-s2976/executive-coaching-s50060/)
Show more Show less
## More relevant reading
* [ Video Analytics What are the main challenges and opportunities of video summarization for online learning platforms? ](https://www.linkedin.com/advice/0/what-main-challenges-opportunities-video-summarization)
* [ Usability Testing What techniques can you use to design learning tasks that support cognitive and affective processes? ](https://www.linkedin.com/advice/1/what-techniques-can-you-use-design-learning-tasks-lkcgf)
* [ Critical Thinking How can you use metaphors to generate alternative solutions? ](https://www.linkedin.com/advice/0/how-can-you-use-metaphors-generate-alternative-dblzc)
* [ Artificial Intelligence How do you design effective contrastive loss functions for semi-supervised learning tasks? ](https://www.linkedin.com/advice/0/how-do-you-design-effective-contrastive)
Help improve contributions
Mark contributions as unhelpful if you find them irrelevant or not valuable to
the article. This feedback is private to you and won’t be shared publicly.
Got it
Contribution hidden for you
This feedback is never shared publicly, we’ll use it to show better
contributions to everyone.
Undo ` `
## Are you sure you want to delete your contribution?
## Are you sure you want to delete your reply?
Cancel
Delete
` ` ` ` ` ` ` ` ` ` ` `
* LinkedIn © 2024
* [ About ](https://about.linkedin.com?trk=article-ssr-frontend-x-article_footer-about)
* [ Accessibility ](https://www.linkedin.com/accessibility?trk=article-ssr-frontend-x-article_footer-accessibility)
* [ User Agreement ](https://www.linkedin.com/legal/user-agreement?trk=article-ssr-frontend-x-article_footer-user-agreement)
* [ Privacy Policy ](https://www.linkedin.com/legal/privacy-policy?trk=article-ssr-frontend-x-article_footer-privacy-policy)
* [ Cookie Policy ](https://www.linkedin.com/legal/cookie-policy?trk=article-ssr-frontend-x-article_footer-cookie-policy)
* [ Copyright Policy ](https://www.linkedin.com/legal/copyright-policy?trk=article-ssr-frontend-x-article_footer-copyright-policy)
* [ Brand Policy ](https://brand.linkedin.com/policies?trk=article-ssr-frontend-x-article_footer-brand-policy)
* [ Guest Controls ](https://www.linkedin.com/psettings/guest-controls?trk=article-ssr-frontend-x-article_footer-guest-controls)
* [ Community Guidelines ](https://www.linkedin.com/legal/professional-community-policies?trk=article-ssr-frontend-x-article_footer-community-guide)
* * العربية (Arabic)
* Čeština (Czech)
* Dansk (Danish)
* Deutsch (German)
* **English (English)**
* Español (Spanish)
* Français (French)
* हिंदी (Hindi)
* Bahasa Indonesia (Indonesian)
* Italiano (Italian)
* 日本語 (Japanese)
* 한국어 (Korean)
* Bahasa Malaysia (Malay)
* Nederlands (Dutch)
* Norsk (Norwegian)
* Polski (Polish)
* Português (Portuguese)
* Română (Romanian)
* Русский (Russian)
* Svenska (Swedish)
* ภาษาไทย (Thai)
* Tagalog (Tagalog)
* Türkçe (Turkish)
* Українська (Ukrainian)
* 简体中文 (Chinese (Simplified))
* 正體中文 (Chinese (Traditional))
Language
` ` ` ` ` ` ` ` ` `
` `
[ Like
](https://www.linkedin.com/uas/login?session_redirect=%2Fadvice%2F0%2Fhow-do-
you-use-memory-techniques-recall-retain&trk=article-ssr-frontend-x-article_x-
social-details_like-toggle_like-cta)
Like
Celebrate
Support
Love
Insightful
Funny
` ` ` `
* Copy
* LinkedIn
* Facebook
* Twitter
Share
` ` ` `
356
` ` ` ` ` ` ` ` ` ` ` ` ` `
13 Contributions
` `
| biology | 28573 | https://nn.wikipedia.org/wiki/Random%20Access%20Memory | Random Access Memory | RAM, frå engelsk random-access memory, er ein type minne i ei datamaskin som blir nytta til å lagra data og programinstruksjonar når maskina er i drift og vert ofte kalla arbeids-RAM. Dette direktelageret kan addresserast vilkårleg (lesast/skrivast frå/til ein vilkårleg addresse). Moderne RAM vert laga av halvleiarar og kan vera bygd som separate integrerte krinsar. Når spenninga vert fjerna går informasjonen tapt, både for SRAM og DRAM. Informasjon ein vil ta vare på må difor lagrast på eit permanent minne, som til dømes eit platelager, før spenninga vert fjerna.
To hovudtypar
Ein skil mellom statisk RAM (SRAM) og dynamisk RAM (DRAM). SRAM lagrar kvar einskild bit i tilstanden til ein Flip-flop, medan DRAM lagrar infrmasjonen i form av ei elektrisk ladning på små kondensatorar. Det trengst minst 6 transistorarar per bit i ein SRAM, medan DRAM — i tillegg til kondensatoren — treng berre ein transistor per bit. DRAM har difor mykje større datatettleik (bit per arealeining) enn SRAM. For å få størst muleg datatettleik er kondensatorane som DRAM lagrar informasjonen på svært små, noko som fører til at dei berre kan halda på ladinga ei stutt tid (nokre titals µs). DRAM har difor innebygd elektronikk som regelmessig les ut informasjonen (spenninga) og skriv han innatt. Denne oppfriskinga syter for at informasjonen ikkje går tapt, så lenge krinsane er kopla til rett spenning. Tidsintervallet mellom kvar oppfrisking er typisk 64 µs.
Både på grunn av at informasjonen er lagra i form av små ladningar og på grunn av at det er naudsynt med regelmessig oppfrisking av informasjonen tek det lengre tid å skriva til eller lesa frå DRAM enn for SRAM. Ein nyttar difor ofte eit SRAM-mellomminne for å redusera forsinkinga ved å lesa frå eller skriva til DRAM.
Bruksområde
Eit viktig bruksområde for RAM er som arbeidsminne i datamaskinar og innbaka system, men RAM vert òg nytta som bufferar i I/O-einingar som lydkort, grafikkort og liknande. ASIC og FPGA kan òg innehalda noko RAM (SRAM), men med mykje mindre datatettleik enn DRAM.
RAM-modular
RAM-brikker har som oftast ei ordlengd på ein Byte (8 bit). På grunn av at mange datamaskinar les/skriv blokker på 32 eller 64 bit er det vanleg at fire eller 8 RAM-brikker vert sett saman til 32- eller 64-bits modular. Det finst fleire typar modular, men den mest vanlege typen i dag (2019) er DIM-modular.
Sjå òg
SRAM
DRAM
VRAM
Flash-minne
PROM
Referansar
Arbeidsminne
Datamaskinminne | norwegian_nynorsk | 1.524369 |
baby_memories/Mirror_test.txt |
The mirror test—sometimes called the mark test, mirror self-recognition (MSR) test, red spot technique, or rouge test—is a behavioral technique developed in 1970 by American psychologist Gordon Gallup Jr. as an attempt to determine whether an animal possesses the ability of visual self-recognition. The MSR test is the traditional method for attempting to measure physiological and cognitive self-awareness. However, agreement has been reached that animals can be self-aware in ways not measured by the mirror test, such as distinguishing between their own and others' songs and scents, and being aware of their own bodies, while humans have abnormally good vision, and thus intelligence that is highly visual.
In the classic MSR test, an animal is anesthetized and then marked (e.g. paint or sticker) on an area of the body the animal normally cannot see (e.g. forehead). When the animal recovers from the anesthetic, it is given access to a mirror. If the animal then touches or investigates the mark, it is taken as an indication that the animal perceives the reflected image as an image of itself, rather than of another animal.
Very few species have passed the MSR test. Species that have include the great apes, a single Asian elephant, Giant oceanic manta rays, dolphins, orcas, the Eurasian magpie, and the cleaner wrasse. A wide range of species has been reported to fail the test, including several species of monkeys, giant pandas, and sea lions.
The inspiration for the mirror test comes from an anecdote about Charles Darwin and a captive orangutan. While visiting the London Zoo in 1838, Darwin observed an orangutan, named Jenny, throwing a tantrum after being teased with an apple by her keeper. This started him thinking about the subjective experience of an orangutan. He also watched Jenny gaze into a mirror and noted the possibility that she recognized herself in the reflection.
In 1970, Gordon Gallup Jr. experimentally investigated the possibility of self-recognition with two male and two female wild preadolescent chimpanzees (Pan troglodytes), none of which had presumably seen a mirror previously. Each chimpanzee was put into a room by itself for two days. Next, a full-length mirror was placed in the room for a total of 80 hours at periodically decreasing distances. A multitude of behaviors was recorded upon introducing the mirrors to the chimpanzees. Initially, the chimpanzees made threatening gestures at their own images, ostensibly seeing their own reflections as threatening. Eventually, the chimps used their own reflections for self-directed responding behaviors, such as grooming parts of their body previously not observed without a mirror, picking their noses, making faces, and blowing bubbles at their own reflections.
Gallup expanded the study by manipulating the chimpanzees' appearance and observing their reaction to their reflection in the mirror. Gallup anesthetized the chimps and then painted a red alcohol-soluble dye on the eyebrow ridge and on the top half of the opposite ear. When the dye dried, it had virtually no olfactory or tactile cues. Gallup then removed the mirror before returning the chimpanzees to the cage. After regaining full consciousness, he then recorded the frequency with which the chimps spontaneously touched the marked areas of skin. After 30 minutes, the mirror was reintroduced into the cage and the frequency of touching the marked areas again determined. The frequency increased four to ten, with the mirror present, compared to only one when the mirror had been removed. The chimpanzees sometimes visually or olfactorily inspected their fingers after touching the marks. Other mark-directed behavior included turning and adjusting of the body to better view the mark in the mirror, or tactile examination of the mark with an appendage while viewing the mirror.
An important aspect of the classical mark-test (or rouge test) is that the mark/dye is nontactile, preventing attention being drawn to the marking through additional perceptual cues (somesthesis). For this reason, animals in the majority of classical tests are anesthetized. Some tests use a tactile marker. If the creature stares unusually long at the part of its body with the mark or tries to rub it off, then it is said to pass the test.
Animals that are considered to be able to recognize themselves in a mirror typically progress through four stages of behavior when facing a mirror:
Gallup conducted a follow-up study in which two chimps with no prior experience of a mirror were put under anesthesia, marked, and observed. After recovery, they made no mark-directed behaviors either before or after being provided with a mirror.
The rouge test was also done by Michael Lewis and Jeanne Brooks-Gunn in 1979 for the purpose of self-recognition with human mothers and their children.
The default implication drawn from Gallup's test is that those animals who pass the test possess some form of self-recognition. However, a number of authors have suggested alternative explanations of a pass. For example, Povinelli suggests that the animal may see the reflection as some odd entity that it is able to control through its own movements. When the reflected entity has a mark on it, then the animal can remove the mark or alert the reflected entity to it using its own movements to do so. Critically, this explanation does not assume that the animals necessarily see the reflected entity as "self".
The MSR test has been criticized for several reasons, in particular because it may result in false negative findings.
It may be of limited value when applied to species that primarily use senses other than vision. Humans have been determined by biologists to have some of the best eyesight amongst animals, exceeding the overwhelming majority in daylight settings, though a few species have better. By contrast, dogs for example mainly use smell and hearing; vision is used third. This may be why dogs fail the MSR test. With this in mind, biologist Marc Bekoff developed a scent-based paradigm using dog urine to test self-recognition in canines. He tested his own dog, but his results were inconclusive. Dog cognition researcher Alexandra Horowitz formalized Bekoff's idea in a controlled experiment, first reported in 2016 and published in 2017. She compared the dogs' behavior when examining their own and others' odors, and also when examining their own odor with an added smell "mark" analogous to the visual mark in MSR tests. These subjects not only discriminated their own odor from that of other dogs, as Bekoff had found, but also spent more time investigating their own odor "image" when it was modified, as subjects who pass the MSR test do. A 2016 study suggested an ethological approach, the "Sniff test of self-recognition (STSR)" which did not shed light on different ways of checking for self-recognition. Dogs also show self-awareness in the size and movement of their bodies.
Another concern with the MSR test is that some species quickly respond aggressively to their mirror reflection as if it were a threatening conspecific, thereby preventing the animal from calmly considering what the reflection actually represents. This may be why gorillas and monkeys fail the MSR test.
In an MSR test, animals may not recognise the mark as abnormal, or may not be sufficiently motivated to react to it. However, this does not mean they are unable to recognize themselves. For example, in an MSR test conducted on three elephants, only one elephant passed the test, but the two elephants that failed still demonstrated behaviors that can be interpreted as self-recognition. The researchers commented that the elephants might not have touched the mark because it was not important enough to them. Similarly, lesser apes infrequently engage in self-grooming, which may explain their failure to touch a mark on their heads in the mirror test. In response to the question of the subject's motivation to clean, another study modified the test by introducing child subjects to a doll with a rouge spot under its eye and asking the child to help clean the doll. After establishing that the mark was abnormal and to be cleaned, the doll was put away and the test continued. This modification increased the number of self-recognisers.
Frans de Waal, a biologist and primatologist at Emory University, has stated that self-awareness is not binary, and the mirror test should not be relied upon as a sole indicator of self-awareness, though it is a good test to have. Different animals adapt to the mirror in different ways.
Several studies using a wide range of species have investigated the occurrence of spontaneous, mark-directed behavior when given a mirror, as originally proposed by Gallup. Most marked animals given a mirror initially respond with social behavior, such as aggressive displays, and continue to do so during repeated testing. Only a few species have touched or directed behavior toward the mark, thereby passing the classic MSR test.
Findings in MSR studies are not always conclusive. Even in chimpanzees, the species most studied and with the most convincing findings, clear-cut evidence of self-recognition is not obtained in all individuals tested. Prevalence is about 75% in young adults and considerably less in young and aging individuals.
Until the 2008 study on magpies, self-recognition was thought to reside in the neocortex area of the brain. However, this brain region is absent in nonmammals. Self-recognition may be a case of convergent evolution, where similar evolutionary pressures result in similar behaviors or traits, although species arrive at them by different routes, and the underlying mechanism may be different.
Some animals that have reportedly failed the classic MSR test include:
Gibbon (g. Hylobates, Symphalangus and Nomascus) have failed to show self-recognition in at least two tests. However, modified mirror tests with three species of gibbons (Hylobates syndactylus, H. gabriellae, H. leucogenys) in 2000 showed convincing evidence of self-recognition even though the animals failed the standard version of the mirror test. Another study published in 2009 documents 12 cases of spontaneous self-recognition in front of the mirror by a pair of siamangs (Symphalangus syndactylus).
Pigs can use visual information seen in a mirror to find food. In a 2009 experiment, seven of the eight pigs who spent 5 hours with a mirror were able to find a bowl of food hidden behind a wall and revealed using a mirror. Pigs that had no experience with mirrors, looked behind the mirror for the food. BBC Earth also showed the food bowl test, and the "matching shapes to holes" test, in the Extraordinary Animals series.
There is evidence of self-recognition when presented with their reflections. So far, pigs have not been observed to pass the mirror mark test, however.
Two captive giant manta rays showed frequent, unusual and repetitive movements in front of a mirror, suggesting contingency checking. They also showed unusual self-directed behaviors when exposed to the mirror. Manta rays have the largest brains of all fish. In 2016, Csilla Ari tested captive manta rays at the Atlantis Aquarium in the Bahamas by exposing them to a mirror. The manta rays appeared to be extremely interested in the mirror. They behaved strangely in front the mirror, including doing flips and moving their fins. They also blew bubbles. They did not interact with the reflection as if it were another manta ray; they did not try to socialize with it. However, only an actual mirror test can determine if they actually recognize their own reflections, or if they are just demonstrating exploratory behavior. A classic mirror test has yet to be done on manta rays.
Another fish that may pass the mirror test is the common archerfish, Toxotes chatareus. A study in 2016 showed that archerfish can discriminate between human faces. Researchers showed this by testing the archerfish, which spit a stream of water at an image of a face when they recognized it. The archerfish would be trained to expect food when it spat at a certain image. When the archerfish was shown images of other human faces, the fish did not spit. They only spit for the image that they recognized. Archerfish normally, in the wild, use their spitting streams to knock down prey from above into the water below. The study showed that archerfish could be trained to recognize a three-dimensional image of one face compared to an image of a different face and would spit at the face when they recognized it. The archerfish were even able to continue recognizing the image of the face even when it was rotated 30, 60 and 90°.
The rouge test is a version of the mirror test used with human children. Using rouge makeup, an experimenter surreptitiously places a dot on the face of the child. The children are then placed in front of a mirror and their reactions are monitored; depending on the child's development, distinct categories of responses are demonstrated. This test is widely cited as the primary measure for mirror self-recognition in human children.
There is criticism that passing a rouge test may be culturally motivated, and that what is commonly thought about mirror self-recognition actually applies only to children of Western countries. A study from 2010 tested children from rural communities in Kenya, Fiji, Saint Lucia, Grenada and Peru, as well as urban United States and rural Canada. The majority of children from the US and Canada passed the MSR test, but fewer children from the other regions passed the MSR test. In the Kenya test, only 3% of children aged 18-72 months touched the mark. In the Fiji test, none of the children aged 36-55 months touched the mark. The other non-Western rural children scored much better, but still markedly worse than their Western counterparts.
In a study in 1972, from the ages of 6 to 12 months, children typically saw a "sociable playmate" in the mirror's reflection. Self-admiring and embarrassment usually began at 12 months, and at 14 to 20 months, most children demonstrated avoidance behaviors. By 20 to 24 months, self-recognition climbed to 65%. Children did so by evincing mark-directed behavior; they touched their own noses or tried to wipe the marks off. In another study, in 1974, at 18 months, half of children recognized the reflection in the mirror as their own.
Self-recognition in mirrors apparently is independent of familiarity with reflecting surfaces. In some cases, the rouge test has been shown to have differing results, depending on sociocultural orientation. For example, a Cameroonian Nso sample of infants 18 to 20 months of age had an extremely low amount of self-recognition outcomes at 3.2%. The study also found two strong predictors of self-recognition: object stimulation (maternal effort of attracting the attention of the infant to an object either person touched) and mutual eye contact. A strong correlation between self-concept and object permanence have also been demonstrated using the rouge test.
The rouge test is a measure of self-concept; the child who touches the rouge on his own nose upon looking into a mirror demonstrates the basic ability to understand self-awareness. Animals, young children, and people who have gained sight after being blind from birth, sometimes react to their reflection in the mirror as though it were another individual.
Theorists have remarked on the significance of this period in a child's life. For example, psychoanalyst Jacques Lacan used a similar test in marking the mirror stage when growing up. Current views of the self in psychology position the self as playing an integral part in human motivation, cognition, affect, and social identity.
In 2012, early steps were taken to make a robot pass the mirror test.
Method and history[edit]
The inspiration for the mirror test comes from an anecdote about Charles Darwin and a captive orangutan. While visiting the London Zoo in 1838, Darwin observed an orangutan, named Jenny, throwing a tantrum after being teased with an apple by her keeper. This started him thinking about the subjective experience of an orangutan. He also watched Jenny gaze into a mirror and noted the possibility that she recognized herself in the reflection.
In 1970, Gordon Gallup Jr. experimentally investigated the possibility of self-recognition with two male and two female wild preadolescent chimpanzees (Pan troglodytes), none of which had presumably seen a mirror previously. Each chimpanzee was put into a room by itself for two days. Next, a full-length mirror was placed in the room for a total of 80 hours at periodically decreasing distances. A multitude of behaviors was recorded upon introducing the mirrors to the chimpanzees. Initially, the chimpanzees made threatening gestures at their own images, ostensibly seeing their own reflections as threatening. Eventually, the chimps used their own reflections for self-directed responding behaviors, such as grooming parts of their body previously not observed without a mirror, picking their noses, making faces, and blowing bubbles at their own reflections.
Gallup expanded the study by manipulating the chimpanzees' appearance and observing their reaction to their reflection in the mirror. Gallup anesthetized the chimps and then painted a red alcohol-soluble dye on the eyebrow ridge and on the top half of the opposite ear. When the dye dried, it had virtually no olfactory or tactile cues. Gallup then removed the mirror before returning the chimpanzees to the cage. After regaining full consciousness, he then recorded the frequency with which the chimps spontaneously touched the marked areas of skin. After 30 minutes, the mirror was reintroduced into the cage and the frequency of touching the marked areas again determined. The frequency increased four to ten, with the mirror present, compared to only one when the mirror had been removed. The chimpanzees sometimes visually or olfactorily inspected their fingers after touching the marks. Other mark-directed behavior included turning and adjusting of the body to better view the mark in the mirror, or tactile examination of the mark with an appendage while viewing the mirror.
An important aspect of the classical mark-test (or rouge test) is that the mark/dye is nontactile, preventing attention being drawn to the marking through additional perceptual cues (somesthesis). For this reason, animals in the majority of classical tests are anesthetized. Some tests use a tactile marker. If the creature stares unusually long at the part of its body with the mark or tries to rub it off, then it is said to pass the test.
Animals that are considered to be able to recognize themselves in a mirror typically progress through four stages of behavior when facing a mirror:
social responsesphysical inspection (e.g. looking behind the mirror)repetitive mirror-testing behaviorrealization of seeing themselves
Gallup conducted a follow-up study in which two chimps with no prior experience of a mirror were put under anesthesia, marked, and observed. After recovery, they made no mark-directed behaviors either before or after being provided with a mirror.
The rouge test was also done by Michael Lewis and Jeanne Brooks-Gunn in 1979 for the purpose of self-recognition with human mothers and their children.
Implication and alternate explanations[edit]
The default implication drawn from Gallup's test is that those animals who pass the test possess some form of self-recognition. However, a number of authors have suggested alternative explanations of a pass. For example, Povinelli suggests that the animal may see the reflection as some odd entity that it is able to control through its own movements. When the reflected entity has a mark on it, then the animal can remove the mark or alert the reflected entity to it using its own movements to do so. Critically, this explanation does not assume that the animals necessarily see the reflected entity as "self".
Criticism[edit]
The MSR test has been criticized for several reasons, in particular because it may result in false negative findings.
It may be of limited value when applied to species that primarily use senses other than vision. Humans have been determined by biologists to have some of the best eyesight amongst animals, exceeding the overwhelming majority in daylight settings, though a few species have better. By contrast, dogs for example mainly use smell and hearing; vision is used third. This may be why dogs fail the MSR test. With this in mind, biologist Marc Bekoff developed a scent-based paradigm using dog urine to test self-recognition in canines. He tested his own dog, but his results were inconclusive. Dog cognition researcher Alexandra Horowitz formalized Bekoff's idea in a controlled experiment, first reported in 2016 and published in 2017. She compared the dogs' behavior when examining their own and others' odors, and also when examining their own odor with an added smell "mark" analogous to the visual mark in MSR tests. These subjects not only discriminated their own odor from that of other dogs, as Bekoff had found, but also spent more time investigating their own odor "image" when it was modified, as subjects who pass the MSR test do. A 2016 study suggested an ethological approach, the "Sniff test of self-recognition (STSR)" which did not shed light on different ways of checking for self-recognition. Dogs also show self-awareness in the size and movement of their bodies.
Another concern with the MSR test is that some species quickly respond aggressively to their mirror reflection as if it were a threatening conspecific, thereby preventing the animal from calmly considering what the reflection actually represents. This may be why gorillas and monkeys fail the MSR test.
In an MSR test, animals may not recognise the mark as abnormal, or may not be sufficiently motivated to react to it. However, this does not mean they are unable to recognize themselves. For example, in an MSR test conducted on three elephants, only one elephant passed the test, but the two elephants that failed still demonstrated behaviors that can be interpreted as self-recognition. The researchers commented that the elephants might not have touched the mark because it was not important enough to them. Similarly, lesser apes infrequently engage in self-grooming, which may explain their failure to touch a mark on their heads in the mirror test. In response to the question of the subject's motivation to clean, another study modified the test by introducing child subjects to a doll with a rouge spot under its eye and asking the child to help clean the doll. After establishing that the mark was abnormal and to be cleaned, the doll was put away and the test continued. This modification increased the number of self-recognisers.
Frans de Waal, a biologist and primatologist at Emory University, has stated that self-awareness is not binary, and the mirror test should not be relied upon as a sole indicator of self-awareness, though it is a good test to have. Different animals adapt to the mirror in different ways.
Non-human animals[edit]
European magpies have demonstrated mirror self-recognition.
Several studies using a wide range of species have investigated the occurrence of spontaneous, mark-directed behavior when given a mirror, as originally proposed by Gallup. Most marked animals given a mirror initially respond with social behavior, such as aggressive displays, and continue to do so during repeated testing. Only a few species have touched or directed behavior toward the mark, thereby passing the classic MSR test.
Findings in MSR studies are not always conclusive. Even in chimpanzees, the species most studied and with the most convincing findings, clear-cut evidence of self-recognition is not obtained in all individuals tested. Prevalence is about 75% in young adults and considerably less in young and aging individuals.
Until the 2008 study on magpies, self-recognition was thought to reside in the neocortex area of the brain. However, this brain region is absent in nonmammals. Self-recognition may be a case of convergent evolution, where similar evolutionary pressures result in similar behaviors or traits, although species arrive at them by different routes, and the underlying mechanism may be different.
Animals that have passed[edit]
Mammals[edit]
Cetaceans[edit]
Bottlenose dolphin (Tursiops truncatus): Researchers in a study on two male bottlenose dolphins observed their reactions to mirrors after having a mark placed on them. Reactions such as decreased delay in approaching the mirror, repetitious head circling and close viewing of the eye or genital region that had been marked, were reported as evidence of MSR in these species.
Killer whale (Orcinus orca): Killer whales and false killer whales (Pseudorca crassidens) may be able to recognise themselves in mirrors.
Primates[edit]
Humans (Homo sapiens)
Bonobo (Pan paniscus)
Bornean orangutan (Pongo pygmaeus): However, mirror tests with an infant (2-year-old), male orangutan failed to reveal self-recognition.
Chimpanzee (Pan troglodytes): However, mirror tests with an infant (11 months old) male chimpanzee failed to reveal self-recognition. Two young chimpanzees showed retention of MSR after one year without access to mirrors.
Western gorilla (Gorilla gorilla): Findings for western gorillas have been mixed; more so than for the other great apes. At least four studies have reported that gorillas failed to show self-recognition. However, other studies have shown self-recognition in captive gorillas with extensive human contact. Such gorillas show less aversion to direct eye contact than wild gorillas. In wild gorillas, as in many other animals, prolonged direct eye contact is an aggressive gesture, and gorillas may fail the mirror test because they deliberately avoid closely examining or making eye contact with their reflections. Gorillas who have passed the MSR were habituated to the mirror before testing and were not subject to anesthesia during the marking process. Koko was among the gorillas who passed the MSR test under these circumstances.
Proboscidea[edit]
Asian elephant (Elephas maximus): In a study performed in 2006, three female Asian elephants were exposed to a large mirror to investigate their responses. Visible marks and invisible sham-marks were applied to the elephants' heads to test whether they would pass the MSR test. One of the elephants showed mark-directed behavior, though the other two did not. An earlier study failed to find MSR in two Asian elephants; it was claimed this was because the mirror was too small.
Birds[edit]
Video of the responses of a European magpie in an MSR test: The magpie repeatedly attempts to remove the marks.
Eurasian magpie (Pica pica): The Eurasian magpie is the first non-mammal to have been found to pass the mirror test. In 2008, researchers applied a small red, yellow, or black sticker to the throat of five Eurasian magpies, where they could be seen by the bird only by using a mirror. The birds were then given a mirror. The feel of the sticker on their throats did not seem to alarm the magpies. However, when the birds with colored stickers glimpsed themselves in the mirror, they scratched at their throats—a clear indication that they recognised the image in the mirror as their own. Those that received a black sticker, invisible against the black neck feathers, did not react. In 2020, researchers attempted to closely replicate the 2008 study with a larger number of magpies, and failed to confirm the results of the 2008 study. The researchers stated that while these results did not disprove the 2008 study, the failure to replicate indicated the results of the original study should be treated with caution.
Some pigeons can pass the mirror test after training in the prerequisite behaviors. In 1981, American psychologist B. F. Skinner found that pigeons are capable of passing a highly modified mirror test after extensive training. In the experiment, a pigeon was trained to look in a mirror to find a response key behind it, which the pigeon then turned to peck to obtain food. Thus, the pigeon learned to use a mirror to find critical elements of its environment. Next, the pigeon was trained to peck at dots placed on its feathers; food was, again, the consequence of touching the dot. The latter training was accomplished in the absence of the mirror. The final test was placing a small bib on the pigeon—enough to cover a dot placed on its lower belly. A control period without the mirror present yielded no pecking at the dot. When the mirror was revealed, the pigeon became active, looked in the mirror and then tried to peck on the dot under the bib. However, untrained pigeons have never passed the mirror test.
Fish[edit]
According to a study done in 2019, cleaner wrasses were the first fish observed to pass the mirror test. The bluestreak cleaner wrasse (Labroides dimidiatus) is a tiny tropical reef cleaner fish. Cleaner fish have an adapted evolutionary behavior in which they remove parasites and dead tissue from larger fish. When put through the mirror test, using a benign brown gel injected into the skin of the fish, and resembling a parasite, the cleaner wrasse showed all the behaviors of passing through the phases of the test. When provided with a colored tag in a modified mark test, the fish attempted to scrape off this tag by scraping their bodies on the side of the mirror. Gordon Gallup believes the cleaner wrasses' behavior can be attributed to something other than recognizing itself in a mirror. Gallup has argued that a cleaner wrasse's job in life is to be aware of ectoparasites on the bodies of other fish, so it would be hyper aware of the fake parasite that it noticed in the mirror, perhaps seeing it as a parasite that it needed to clean off of a different fish. The authors of the study retort that because the fish checked itself in the mirror before and after the scraping, this means that the fish has self-awareness and recognizes that its reflection belongs to its own body. The cleaner wrasses, when tested, spent a large amount of time with the mirror when they were first getting acquainted with it, without any training. Importantly, the cleaner wrasses performed scraping behavior with the colored mark, and they did not perform the same scraping behavior without the colored mark in the presence of the mirror, nor when they were with the mirror and had a transparent mark. Following various objections, the researchers published a follow-up study in 2022, where they did the mirror test on a larger sample of wrasses and experimented with several marking techniques. The new results "increase[d] [the researchers'] confidence that cleaner fish indeed pass the mark test", although wrasses attempted to scrape off the mark only when it resembled a parasite.
In 2016 a modified mirror test done on two captive manta rays (Mobula birostris) showed that they exhibited behavior associated with self-awareness (i.e. contingency checking and unusual self-directed behavior).
Crustaceans[edit]
Atlantic ghost crab (Ocypode quadrata): A 2023 study found that these crabs seem to be capable of recognizing themselves in a mirror. The study's author concluded that the data indicate that the crabs have "a rudimentary form of self-awareness".
Animals that have failed[edit]
Some animals that have reportedly failed the classic MSR test include:
Mammals[edit]
Carnivorans[edit]
Sea lions (Zalophus californianus)
Giant panda (Ailuropoda melanoleuca): In one study, 34 captive giant pandas of a wide range of ages were tested. None of the pandas responded to the mark and many reacted aggressively towards the mirror, causing the researchers to consider the pandas viewed their reflection as a conspecific.
Dogs (Canis lupus familiaris): Dogs either treat the image as another animal, or come to ignore it completely.
Primates[edit]
Stump-tailed macaque (Macaca arctoides)
Crab-eating macaque (Macaca fascicularis)
Rhesus macaque (Macaca mulatta): However, it has been reported that rhesus monkeys exhibit other behaviours in response to a mirror that indicate self-recognition. Rhesus macaques have been observed to use mirrors to study otherwise-hidden parts of their bodies, such as their genitals and implants in their heads. It has been suggested this demonstrates at least a partial self-awareness, although this is disputed.
Black-and-white colobus (Colobus guereza)
Capuchin monkey (Cebus apella)
Hamadryas baboon (Papio hamadryas)
Cotton-top tamarin (Saguinus oedipus)
Birds[edit]
Grey parrot
New Caledonian crow
Jackdaw
Great tit (Parus major)
Fish[edit]
The Tanganyikan cichlid, or daffodil cichlid (Neolamprologus pulcher), is another fish that has failed the mirror test, according to a study done in 2017. Although not cleaner fish like the cleaner wrasses, these fish are typically regarded as socially intelligent and can recognize conspecifics in their social groups. Therefore, they would theoretically make good candidates for the mirror test, but they ended up failing. Similar to the cleaner wrasse, the Tanganyikan cichlid first exhibited signs of aggression towards the mirrored image. After a colored mark was injected, the researchers found no increased scraping or trying to remove the mark, and the cichlids did not observe the side with the mark any longer than it would have otherwise. This demonstrates a lack of contingency checking and means that the Tanganyikan cichlid did not pass the mirror test.
Cephalopods[edit]
Octopuses oriented towards their image in a mirror, but no difference in their behaviour (as observed by humans) was seen in this condition when compared with a view of other octopuses.
Animals that may pass[edit]
Mammals[edit]
Primates[edit]
Gibbon (g. Hylobates, Symphalangus and Nomascus) have failed to show self-recognition in at least two tests. However, modified mirror tests with three species of gibbons (Hylobates syndactylus, H. gabriellae, H. leucogenys) in 2000 showed convincing evidence of self-recognition even though the animals failed the standard version of the mirror test. Another study published in 2009 documents 12 cases of spontaneous self-recognition in front of the mirror by a pair of siamangs (Symphalangus syndactylus).
Pigs[edit]
Pigs can use visual information seen in a mirror to find food. In a 2009 experiment, seven of the eight pigs who spent 5 hours with a mirror were able to find a bowl of food hidden behind a wall and revealed using a mirror. Pigs that had no experience with mirrors, looked behind the mirror for the food. BBC Earth also showed the food bowl test, and the "matching shapes to holes" test, in the Extraordinary Animals series.
There is evidence of self-recognition when presented with their reflections. So far, pigs have not been observed to pass the mirror mark test, however.
Fish[edit]
Two captive giant manta rays showed frequent, unusual and repetitive movements in front of a mirror, suggesting contingency checking. They also showed unusual self-directed behaviors when exposed to the mirror. Manta rays have the largest brains of all fish. In 2016, Csilla Ari tested captive manta rays at the Atlantis Aquarium in the Bahamas by exposing them to a mirror. The manta rays appeared to be extremely interested in the mirror. They behaved strangely in front the mirror, including doing flips and moving their fins. They also blew bubbles. They did not interact with the reflection as if it were another manta ray; they did not try to socialize with it. However, only an actual mirror test can determine if they actually recognize their own reflections, or if they are just demonstrating exploratory behavior. A classic mirror test has yet to be done on manta rays.
Another fish that may pass the mirror test is the common archerfish, Toxotes chatareus. A study in 2016 showed that archerfish can discriminate between human faces. Researchers showed this by testing the archerfish, which spit a stream of water at an image of a face when they recognized it. The archerfish would be trained to expect food when it spat at a certain image. When the archerfish was shown images of other human faces, the fish did not spit. They only spit for the image that they recognized. Archerfish normally, in the wild, use their spitting streams to knock down prey from above into the water below. The study showed that archerfish could be trained to recognize a three-dimensional image of one face compared to an image of a different face and would spit at the face when they recognized it. The archerfish were even able to continue recognizing the image of the face even when it was rotated 30, 60 and 90°.
Humans[edit]
A human child exploring his reflection
The rouge test is a version of the mirror test used with human children. Using rouge makeup, an experimenter surreptitiously places a dot on the face of the child. The children are then placed in front of a mirror and their reactions are monitored; depending on the child's development, distinct categories of responses are demonstrated. This test is widely cited as the primary measure for mirror self-recognition in human children.
There is criticism that passing a rouge test may be culturally motivated, and that what is commonly thought about mirror self-recognition actually applies only to children of Western countries. A study from 2010 tested children from rural communities in Kenya, Fiji, Saint Lucia, Grenada and Peru, as well as urban United States and rural Canada. The majority of children from the US and Canada passed the MSR test, but fewer children from the other regions passed the MSR test. In the Kenya test, only 3% of children aged 18-72 months touched the mark. In the Fiji test, none of the children aged 36-55 months touched the mark. The other non-Western rural children scored much better, but still markedly worse than their Western counterparts.
Developmental reactions[edit]
In a study in 1972, from the ages of 6 to 12 months, children typically saw a "sociable playmate" in the mirror's reflection. Self-admiring and embarrassment usually began at 12 months, and at 14 to 20 months, most children demonstrated avoidance behaviors. By 20 to 24 months, self-recognition climbed to 65%. Children did so by evincing mark-directed behavior; they touched their own noses or tried to wipe the marks off. In another study, in 1974, at 18 months, half of children recognized the reflection in the mirror as their own.
Self-recognition in mirrors apparently is independent of familiarity with reflecting surfaces. In some cases, the rouge test has been shown to have differing results, depending on sociocultural orientation. For example, a Cameroonian Nso sample of infants 18 to 20 months of age had an extremely low amount of self-recognition outcomes at 3.2%. The study also found two strong predictors of self-recognition: object stimulation (maternal effort of attracting the attention of the infant to an object either person touched) and mutual eye contact. A strong correlation between self-concept and object permanence have also been demonstrated using the rouge test.
Implications[edit]
The rouge test is a measure of self-concept; the child who touches the rouge on his own nose upon looking into a mirror demonstrates the basic ability to understand self-awareness. Animals, young children, and people who have gained sight after being blind from birth, sometimes react to their reflection in the mirror as though it were another individual.
Theorists have remarked on the significance of this period in a child's life. For example, psychoanalyst Jacques Lacan used a similar test in marking the mirror stage when growing up. Current views of the self in psychology position the self as playing an integral part in human motivation, cognition, affect, and social identity.
Robots[edit]
In 2012, early steps were taken to make a robot pass the mirror test.
See also[edit]
Animal consciousness
Cognitive tests
Embodied cognition
Face perception
Self-agency
Visual perception
Visual system | biology | 4659485 | https://sv.wikipedia.org/wiki/Psidium%20reversum | Psidium reversum | Psidium reversum är en myrtenväxtart som beskrevs av Ignatz Urban. Psidium reversum ingår i släktet Psidium och familjen myrtenväxter. Inga underarter finns listade i Catalogue of Life.
Källor
Myrtenväxter
reversum | swedish | 1.356548 |
baby_memories/sciencebackedmemoryt.txt | [ 
 
 ](https://www.usa.edu)
### Programs
### Pages
### Events
### Faculty
### University Administration
### Posts
* [ Careers @ USA ](https://careers.usa.edu/)
* [ For Alumni ](https://www.usa.edu/about/usahs-alumni/)
* [ For Current Students ](https://www.usa.edu/for-current-students/)
* [ Request Information ](https://www.usa.edu/rfi/)
* [ Apply Now ](https://www.usa.edu/apply-now/)
### Programs
### Pages
### Events
### Faculty
### University Administration
### Posts
* [ Explore Our Programs ](https://www.usa.edu/degree-programs/ "Programs")
* [ College of Rehabilitative Sciences ](https://www.usa.edu/college-of-rehabilitative-sciences/)
* [ Occupational Therapy Programs ](https://www.usa.edu/programs/occupational-therapy-programs/)
* [ Master of Occupational Therapy (MOT) ](/college-of-rehabilitative-sciences/master-of-occupational-therapy-mot/)
* [ Doctor of Occupational Therapy (OTD) ](/college-of-rehabilitative-sciences/doctor-occupational-therapy/)
* [ Post-Professional Doctor of Occupational Therapy (PPOTD) ](/college-of-rehabilitative-sciences/post-professional-doctor-occupational-therapy-pp-otd/)
* [ College of Health Sciences ](https://www.usa.edu/college-health-sciences/)
* [ Master of Science in Physician Assistant Studies (MSPAS) ](https://www.usa.edu/college-health-sciences/master-of-science-in-physician-assistant-studies-mspas-program/)
* [ Master of Health Administration (MHA) ](/mha/)
* [ Doctor of Education (EdD) ](/doctor-of-education-edd-program/)
* [ Graduate Certificates ](https://www.usa.edu/program/graduate-certificates/)
* [ Continuing Professional Education ](https://cpe.usa.edu/learn)
* [ Clinical Orthopedic Residency (OCS) ](/clinical-orthopaedic-residency/)
* [ Orthopaedic Manual Physical Therapy Fellowship (OMPT) ](/orthopaedic-manual-physical-therapy-fellowship/)
* [ Continuing Professional Education (CPE) ](https://www.usa.edu/continuing-professional-education-cpe/)
* [ Physical Therapy Programs ](https://www.usa.edu/college-of-rehabilitative-sciences/physical-therapy-programs/)
* [ Doctor of Physical Therapy (DPT) ](/college-of-rehabilitative-sciences/doctor-physical-therapy/)
* [ Non-Degree Physical Therapy Online Courses ](https://www.usa.edu/college-of-rehabilitative-sciences/physical-therapy-online-courses-international-students/)
* [ Master of Science in Speech-Language Pathology (MS-SLP) ](/college-of-rehabilitative-sciences/master-science-speech-language-pathology-ms-slp/)
* [ School of Nursing ](/college-health-sciences/school-of-nursing/)
* [ Post-Graduate Nursing Certificates ](/college-health-sciences/school-of-nursing/post-graduate-nursing-certs/)
* [ Master of Science in Nursing (MSN) ](/college-health-sciences/school-of-nursing/master-science-nursing-msn/)
* [ Doctor of Nursing Practice (DNP) ](/college-health-sciences/school-of-nursing/doctor-of-nursing-practice-dnp/)
* [ Browse All Degree-Programs ](https://www.usa.edu/degree-programs/)
* [ Admissions & Aid ](https://www.usa.edu/admissions-aid/ "Admissions")
* [ Admissions & Aid Home ](https://www.usa.edu/admissions-aid/)
* * [ Scholarships & Grants ](https://www.usa.edu/scholarships/)
* [ How to Apply ](https://www.usa.edu/apply-now/)
* [ Cost of Attendance ](https://www.usa.edu/cost-by-term/)
* [ Financial Aid ](https://www.usa.edu/admissions-aid/financial-aid/)
* [ Application Deadlines ](https://www.usa.edu/admissions-aid/application-deadlines/)
* [ Academic Calendar ](https://www.usa.edu/admissions-aid/academic-calendar/)
* [ Financial Aid FAQ ](https://www.usa.edu/admissions-aid/financial-aid/frequently-asked-questions-faqs/)
* [ Admissions FAQs ](https://www.usa.edu/admissions-aid/admissions-faqs/)
* [ Catalog/Handbook ](https://catalog.usa.edu/)
* [ About ](https://www.usa.edu/about/)
* [ Why USAHS ](https://www.usa.edu/innovative-learning-model)
* Essential Information
* [ USAHS Shop ](https://shopusahs.inkwellstores.com/Category)
* [ Our History ](https://www.usa.edu/about/history-of-university-of-st-augustine-for-health-sciences/)
* [ Accreditation ](https://www.usa.edu/about/accreditation/)
* [ B Corp Certified ](https://www.usa.edu/about/b-corp-certified/)
* [ Student Achievement Data ](https://www.usa.edu/about/student-achievement-data/)
* [ Institutional Learning Outcomes (ILOs) ](https://www.usa.edu/about/institutional-learning-outcomes-ilos/)
* [ News ](https://www.usa.edu/blog/category/news/)
* [ Diversity & Inclusion ](https://www.usa.edu/about/inclusion-diversity-equity-access/)
* [ Explore All Campuses ](https://www.usa.edu/about/our-campuses/ "Campuses")
* [ San Marcos, California ](https://www.usa.edu/about/our-campuses/san-marcos-ca/)
* [ St. Augustine, Florida ](https://www.usa.edu/about/our-campuses/st-augustine-fl/)
* [ Miami, Florida ](https://www.usa.edu/about/our-campuses/about-our-campuses-miami-fl/)
* [ Austin, Texas ](https://www.usa.edu/about/our-campuses/austin-tx/)
* [ Dallas, Texas ](https://www.usa.edu/about/our-campuses/dallas-tx/)
* People
* [ Our Faculty ](https://www.usa.edu/university-faculty/)
* [ Leadership ](https://www.usa.edu/university-administration/)
* [ Board of Directors ](https://www.usa.edu/about/board-of-directors/)
* [ Alumni ](https://www.usa.edu/about/usahs-alumni/)
* [ Careers ](https://careers.usa.edu/)
* [ Events ](https://www.usa.edu/events/)
* [ Blog ](https://www.usa.edu/blog/ "Blog")
* [ Request Information ](https://www.usa.edu/rfi/)
* [ Apply Now ](https://www.usa.edu/apply-now/)
[ 
 
 ](https://www.usa.edu)
### Programs
### Pages
### Events
### Faculty
### University Administration
### Posts
Search for: Search
Close
* [ Explore Our Programs ](https://www.usa.edu/degree-programs/ "Programs")
* [ College of Rehabilitative Sciences ](https://www.usa.edu/college-of-rehabilitative-sciences/)
* [ Occupational Therapy Programs ](https://www.usa.edu/programs/occupational-therapy-programs/)
* [ Master of Occupational Therapy (MOT) ](/college-of-rehabilitative-sciences/master-of-occupational-therapy-mot/)
* [ Doctor of Occupational Therapy (OTD) ](/college-of-rehabilitative-sciences/doctor-occupational-therapy/)
* [ Post-Professional Doctor of Occupational Therapy (PPOTD) ](/college-of-rehabilitative-sciences/post-professional-doctor-occupational-therapy-pp-otd/)
* [ College of Health Sciences ](https://www.usa.edu/college-health-sciences/)
* [ Master of Science in Physician Assistant Studies (MSPAS) ](https://www.usa.edu/college-health-sciences/master-of-science-in-physician-assistant-studies-mspas-program/)
* [ Master of Health Administration (MHA) ](/mha/)
* [ Doctor of Education (EdD) ](/doctor-of-education-edd-program/)
* [ Graduate Certificates ](https://www.usa.edu/program/graduate-certificates/)
* [ Continuing Professional Education ](https://cpe.usa.edu/learn)
* [ Clinical Orthopedic Residency (OCS) ](/clinical-orthopaedic-residency/)
* [ Orthopaedic Manual Physical Therapy Fellowship (OMPT) ](/orthopaedic-manual-physical-therapy-fellowship/)
* [ Continuing Professional Education (CPE) ](https://www.usa.edu/continuing-professional-education-cpe/)
* [ Physical Therapy Programs ](https://www.usa.edu/college-of-rehabilitative-sciences/physical-therapy-programs/)
* [ Doctor of Physical Therapy (DPT) ](/college-of-rehabilitative-sciences/doctor-physical-therapy/)
* [ Non-Degree Physical Therapy Online Courses ](https://www.usa.edu/college-of-rehabilitative-sciences/physical-therapy-online-courses-international-students/)
* [ Master of Science in Speech-Language Pathology (MS-SLP) ](/college-of-rehabilitative-sciences/master-science-speech-language-pathology-ms-slp/)
* [ School of Nursing ](/college-health-sciences/school-of-nursing/)
* [ Post-Graduate Nursing Certificates ](/college-health-sciences/school-of-nursing/post-graduate-nursing-certs/)
* [ Master of Science in Nursing (MSN) ](/college-health-sciences/school-of-nursing/master-science-nursing-msn/)
* [ Doctor of Nursing Practice (DNP) ](/college-health-sciences/school-of-nursing/doctor-of-nursing-practice-dnp/)
* [ Browse All Degree-Programs ](https://www.usa.edu/degree-programs/)
* [ Admissions & Aid ](https://www.usa.edu/admissions-aid/ "Admissions")
* [ Admissions & Aid Home ](https://www.usa.edu/admissions-aid/)
* * [ Scholarships & Grants ](https://www.usa.edu/scholarships/)
* [ How to Apply ](https://www.usa.edu/apply-now/)
* [ Cost of Attendance ](https://www.usa.edu/cost-by-term/)
* [ Financial Aid ](https://www.usa.edu/admissions-aid/financial-aid/)
* [ Application Deadlines ](https://www.usa.edu/admissions-aid/application-deadlines/)
* [ Academic Calendar ](https://www.usa.edu/admissions-aid/academic-calendar/)
* [ Financial Aid FAQ ](https://www.usa.edu/admissions-aid/financial-aid/frequently-asked-questions-faqs/)
* [ Admissions FAQs ](https://www.usa.edu/admissions-aid/admissions-faqs/)
* [ Catalog/Handbook ](https://catalog.usa.edu/)
* [ About ](https://www.usa.edu/about/)
* [ Why USAHS ](https://www.usa.edu/innovative-learning-model)
* Essential Information
* [ USAHS Shop ](https://shopusahs.inkwellstores.com/Category)
* [ Our History ](https://www.usa.edu/about/history-of-university-of-st-augustine-for-health-sciences/)
* [ Accreditation ](https://www.usa.edu/about/accreditation/)
* [ B Corp Certified ](https://www.usa.edu/about/b-corp-certified/)
* [ Student Achievement Data ](https://www.usa.edu/about/student-achievement-data/)
* [ Institutional Learning Outcomes (ILOs) ](https://www.usa.edu/about/institutional-learning-outcomes-ilos/)
* [ News ](https://www.usa.edu/blog/category/news/)
* [ Diversity & Inclusion ](https://www.usa.edu/about/inclusion-diversity-equity-access/)
* [ Explore All Campuses ](https://www.usa.edu/about/our-campuses/ "Campuses")
* [ San Marcos, California ](https://www.usa.edu/about/our-campuses/san-marcos-ca/)
* [ St. Augustine, Florida ](https://www.usa.edu/about/our-campuses/st-augustine-fl/)
* [ Miami, Florida ](https://www.usa.edu/about/our-campuses/about-our-campuses-miami-fl/)
* [ Austin, Texas ](https://www.usa.edu/about/our-campuses/austin-tx/)
* [ Dallas, Texas ](https://www.usa.edu/about/our-campuses/dallas-tx/)
* People
* [ Our Faculty ](https://www.usa.edu/university-faculty/)
* [ Leadership ](https://www.usa.edu/university-administration/)
* [ Board of Directors ](https://www.usa.edu/about/board-of-directors/)
* [ Alumni ](https://www.usa.edu/about/usahs-alumni/)
* [ Careers ](https://careers.usa.edu/)
* [ Events ](https://www.usa.edu/events/)
* [ Blog ](https://www.usa.edu/blog/ "Blog")
* [ Request Information ](https://www.usa.edu/rfi/)
* [ Apply Now ](https://www.usa.edu/apply-now/)
* [ Careers @ USA ](https://careers.usa.edu/)
* [ For Alumni ](https://www.usa.edu/about/usahs-alumni/)
* [ For Current Students ](https://www.usa.edu/for-current-students/)
* [ Request Information ](https://www.usa.edu/rfi/)
* [ Apply Now ](https://www.usa.edu/apply-now/)
1. [ The latest from USA ](https://www.usa.edu/blog/)
2. [ Science-Backed Memory Tips and Recall Techniques ](https://www.usa.edu/blog/science-backed-memory-tips/)
Editorial
| 8 May 2020
The data in this blog is for general informational purposes only and
information presented was accurate as of the publication date.
# Science-Backed Memory Tips and Recall Techniques
 Memory plays an essential
role in everyday life, enabling us to learn about the world around us and
adapt accordingly. We use memory in every moment, whether it be for
remembering our clients’ first names, studying for a [ nursing school
](https://www.usa.edu/college-health-sciences/school-of-nursing/) exam, or
countless other aspects of our work and life.
Information we take in goes through the three stages of memory: encoding,
storage, and retrieval. The encoding process converts information into a
construct stored in the brain. Then the information is stored as either a
long-term memory or short-term memory . Finally, information is available
to be retrieved from storage.
There are several ways to facilitate this process, protect against memory
decline, and enhance our ability to retain information. Below, we outline
strategies for boosting brain health, as well as specific techniques for
memorizing and recalling information.
## Tips for Memory Improvement
 The best way to protect and improve memory is by making
good lifestyle choices: exercising regularly, limiting stress, eating
healthfully, and getting enough sleep. You can also keep the mind agile by
learning a foreign language or playing [ brain training games
](https://www.health.harvard.edu/mind-and-mood/the-thinking-on-brain-games) to
improve thinking skills and short-term memory.
* **Exercise regularly** : Exercise is one of the best things you can do to protect your memory. Regular aerobic exercise (cardio) [ appears to boost the size of the hippocampus ](https://www.health.harvard.edu/blog/regular-exercise-changes-brain-improve-memory-thinking-skills-201404097110) , the area of the brain involved in verbal memory and learning. Regular exercise can also help you maintain a healthy weight, reduce stress, and sleep better, all of which are related to memory.
* **Limit stress** : Meditation and mindfulness are also great ways to reduce stress and improve sleep. Meditation has been shown to [ improve episodic memory ](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6738165/) , the memory of everyday events.
* **Be conscious of what you consume** : Not surprisingly, what you put into your body can also affect your memory. Consuming a balanced diet that includes healthy fats and natural sugar (glucose)—and limits saturated fat, refined sugar, and alcohol—may be best for promoting long-term memory function.
* **Sleep:** Sleep is critical, as it plays a role in consolidating of memories. Also, a lack of sleep can impair an individual’s ability to concentrate. You can improve sleep by exercising regularly, engaging in mindfulness/meditation, limiting alcohol, and avoiding caffeine in the afternoon and evening.
## 8 Memory Techniques for Retaining Information
When studying for an exam, preparing a presentation, or getting ready to
deliver a speech, you will likely need to memorize information.
Before you start preparing, you can do several things to set yourself up for
success. Try to avoid distractions while you’re studying, plan ahead so you
don’t need to cram, and take study breaks. Evidence suggests that studying
shortly [ before going to sleep
](https://journals.sagepub.com/doi/abs/10.1177/0956797616659930) , as well as
sleeping between learning sessions, can help people retain information.
Below are 8 science-backed techniques for retaining information and improving
recall and memory performance .
**1\. Or** **ganize the information**
Start by outlining the information you will need to recall. Creating a
detailed, but organized outline of the information allows you to highlight and
focus on important concepts.
A useful organization strategy is the **chunking method** , which breaks
down large amounts of information into smaller, logical units that are easy to
understand. For example, when learning a foreign language, you can list
vocabulary words in functional groups such as household items, animals, and
occupations. Chunking is a valuable tool for memorization.
**2\. Make associations**
Creating associations by drawing on existing knowledge is another helpful way
to memorize information. You can create mental images and connect with sounds,
smells, and tastes to help encode memories.
 The [ **Baker/baker paradox**
](https://www.cnn.com/2012/06/10/opinion/foer-ted-memory/index.html) tells us
that if two individuals are to remember that someone’s last name is Baker,
they are much more likely to do so if they picture the person as a
professional baker (i.e., Mr. Baker wearing a chef’s hat). This is why
developing a story is a powerful way to retain information. For example, if
you want to remember that a client’s name is Sandy, you might picture her
walking along a beach.
**3\. Use visual cues**
Using visual tools such as concept maps, graphs, illustrations, and photos can
be beneficial for learning. Graphs and charts also simplify information,
making it easier to comprehend and later recall.
This method can be beneficial to visual learners, meaning individuals who
better conceptualize information they can see. It’s also a great technique for
presenters who can use visuals in their slide deck as retrieval cues.
Aside from being a great memory technique for retaining information, visual
cues are also great for boosting spatial memory . Research has shown that
visual cues have helped spatial navigation among AD and MCI patients.
**4\. Create mnemonics**
Using mnemonic devices, such as acronyms, acrostics, and rhymes, is a good way
to memorize information long-term. For example, do you remember what year
Columbus landed in America? You likely do if you ever learned the rhyme, “In
1492, Columbus sailed the ocean blue.” So if you need to remember a series of
numbers for work, you might consider coming up with a creative rhyme.
For more visual learners, another mnemonic device you can use is building a
memory palace . A memory palace is an imaginary place (it can be a house or
a familiar venue) where you can store mnemonic images. The idea behind this is
you take a journey in your mind to recall the information. Some contestants in
the World Memory Championship would even incorporate a story method with
their memory palace.
**5\. Write it down**
 It turns out that some
things are just better done the old-fashioned way. Researchers have found that
writing down information by hand is [ more effective than typing
](https://www.npr.org/2016/04/17/474525392/attention-students-put-your-
laptops-away) for learning concepts. Because it takes longer to write by hand,
you are naturally forced to be more selective with what you write and focus
only on the key information. In fact, less is more when it comes to note
taking. [ One study showed
](https://www.npr.org/2016/04/17/474525392/attention-students-put-your-
laptops-away) that the more words students wrote down verbatim when note
taking, the worse they performed on recall tests.
**6\. Say it out loud**
When you need to remember new information, it’s helpful to read it aloud. [
One study determined
](https://www.sciencedaily.com/releases/2017/12/171201090940.htm) that the
dual action of speaking and hearing ourselves talk helps get words and phrases
into long-term memory. This study, among others, confirms that memory benefits
from active involvement.
**7\. Engage in active recall**
Testing yourself forces you to pull information from your memory. Flashcards
are a great way to self-test. [ Studies show
](https://www.sciencedirect.com/science/article/pii/S0167876019305616) that
retrieval practice can greatly enhance recollection than simply restudying
materials. This is likely a very effective way to commit things to memory
because of the significant extra effort involved.
**8\. Rehearse**
Practice really does make perfect. Rehearse information over and over, either
by writing it down or reading it aloud.
[ Studies suggest ](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5476736/)
that spaced repetition—spacing out learning over a longer period of time—is a
more effective way to memorize information than trying to “cram” a lot of
information into your brain over a short period of time.
All of these memory techniques are not only backed up by science, but even
memory champions can attest to their efficacy. Even if you aren’t a memory
athlete , these memorization techniques can help you at school or at work.
Check out our posts on [ effective study techniques
](https://www.usa.edu/blog/study-techniques/) and [ learning from home
](https://www.usa.edu/blog/tips-on-learning-from-home/) for further
information.
**Sources:**
Indeed Editorial Team. Indeed. “Nurse Practitioner vs. Family Nurse
Practitioner: Definitions and How They Differ.” May 13, 2021. [
https://www.indeed.com/career-advice/finding-a-job/fnp-vs-np.
](https://www.indeed.com/career-advice/finding-a-job/fnp-vs-np/) Accessed:
January 26, 2022
Karpicke, Jeffrey D. and Henry L. Roediger III. “The Critical Importance of
Retrieval for Learning.” Science 319, no. 5865 (February 2008): 966–968. doi:
10.1126/science.1152408.
Trafton, Anne. “In the blink of an eye.” MIT News. January 16, 2014. [
https://news.mit.edu/2014/in-the-blink-of-an-eye-0116.
](https://news.mit.edu/2014/in-the-blink-of-an-eye-0116/) Accessed: January
26, 2022
## ARE YOU INSPIRED?
There could be an article about you here one day. Take charge of your own
life-story!
[ Request Information ](https://www.usa.edu/rfi/)
Inspired?
Take charge of your own life-story
[ Request Information ](https://www.usa.edu/rfi/)
[ Request Information ](https://www.usa.edu/rfi/)
## More Editorial Articles
[
 Editorial
### How to Become a Physical Therapist in 6 Steps
Ranked the third best healthcare career, physical therapy (PT) is rich in
opportunity ... Read More ](https://www.usa.edu/blog/how-to-become-a-
physical-therapist/)
[
 Editorial
### Occupational Therapy vs. Physical Therapy
If you’ve ever felt called to work in rehabilitative care, one thing is clear:
... Read More ](https://www.usa.edu/blog/occupational-therapy-vs-physical-
therapy/)
[
 Editorial
### What Is a Speech Language Pathologist & What Do They Do?
A speech-language pathologist (SLP) diagnoses and treats issues related to
speech, ... Read More ](https://www.usa.edu/blog/what-is-a-speech-
pathologist/)
## Upcoming Editorial events
[ 
](https://www.usa.edu/event/doctor-of-education-edd-webinar-may-1-400-pm-pdt/)
### [ Doctor of Education (EdD) Webinar - May 1 @ 4:00 pm PDT
](https://www.usa.edu/event/doctor-of-education-edd-webinar-may-1-400-pm-pdt/)
May 1 @ 4:00 pm PDT
[ 
](https://www.usa.edu/event/fellowship-residency-programs-webinar-
may-8-530-pm-pdt/)
### [ Fellowship & Residency Programs Webinar - May 8 @ 5:30 pm PDT
](https://www.usa.edu/event/fellowship-residency-programs-webinar-
may-8-530-pm-pdt/)
May 8 @ 5:30 pm PDT
[ 
](https://www.usa.edu/event/post-professional-doctor-of-occupational-therapy-
otd-webinar-may-14-400-pm-pdt/)
### [ Post Professional Doctor of Occupational Therapy (OTD) Webinar - May 14
@ 4:00 pm PDT ](https://www.usa.edu/event/post-professional-doctor-of-
occupational-therapy-otd-webinar-may-14-400-pm-pdt/)
May 14 @ 4:00 pm PDT
See More
[ 
 ](https://www.usa.edu)
**[ San Marcos, CA Campus ](https://www.usa.edu/about/our-campuses/san-marcos-
ca/) **
700 Windy Point Drive
San Marcos, CA 92069
**[ St. Augustine, FL Campus ](https://www.usa.edu/about/our-campuses/st-
augustine-fl/) **
1 University Boulevard
St. Augustine, FL 32086
**[ Miami, FL Campus ](https://www.usa.edu/about/our-campuses/about-our-
campuses-miami-fl/) **
Douglas Entrance North Tower 800 S. Douglas Road, Suite 149
Coral Gables, FL 33134
**[ Austin, TX Campus ](https://www.usa.edu/about/our-campuses/austin-tx/) **
5401 La Crosse Ave
Austin, TX 78739
**[ Dallas, TX Campus ](https://www.usa.edu/about/our-campuses/dallas-tx/) **
901 W Walnut Hill Lane, Suite 210A
Irving, Texas 75038
**General Inquiries** : (800) 241-1027
**Media Inquiries** : (760) 407-2301
**Fax** : (904) 826-0085
**Registrations** : (800) 241-1027
[ __ ](https://www.facebook.com/universityofstaugustine "Facebook") [ __
](https://www.instagram.com/uofstaug/ "Instagram") [ __
](https://www.youtube.com/user/uofstaug "YouTube") [ __
](https://www.linkedin.com/company/university-of-st-augustine-for-health-
sciences "LinkedIn") [ __ ](https://www.tiktok.com/@uofstaug/ "TikTok")
* [ Why USAHS ](https://www.usa.edu/innovative-learning-model/)
* [ Our History ](https://www.usa.edu/about/history-of-university-of-st-augustine-for-health-sciences/)
* [ Innovative Learning Model ](https://www.usa.edu/innovative-learning-model/)
* [ B Corp Certified ](https://www.usa.edu/about/b-corp-certified/)
* [ Leadership ](https://www.usa.edu/university-administration/)
* [ Our Faculty ](https://www.usa.edu/university-faculty/)
* [ Diversity and Inclusion ](https://www.usa.edu/why-usa/diversity-and-inclusion/)
* [ Explore Our Programs ](https://www.usa.edu/degree-programs/)
* [ College of Rehabilitative Sciences ](https://www.usa.edu/college-of-rehabilitative-sciences/)
* [ College of Health Sciences ](https://www.usa.edu/college-health-sciences/)
* [ Continuing Professional Education ](https://cpe.usa.edu/learn)
* [ Admissions & aid ](https://www.usa.edu/admissions-aid/)
* [ How to Apply ](https://www.usa.edu/apply-now/)
* [ Admissions FAQs ](https://www.usa.edu/admissions-aid/admissions-faqs/)
* [ Application Deadlines ](https://www.usa.edu/admissions-aid/application-deadlines/)
* [ Tuition & Fees ](https://www.usa.edu/cost-by-term/)
* [ Financial Aid ](https://www.usa.edu/admissions-aid/financial-aid/)
* Important Resources
* [ Contact Us ](/about/contact-us/)
* [ MyUSA ](https://my.usa.edu/ics)
* [ Webmail ](https://outlook.com/owa/usa.edu)
* [ Library ](https://www.usa.edu/library/)
* [ USAHS Shop ](https://shopusahs.inkwellstores.com/Category)
* [ Complaints ](https://www.usa.edu/legal/complaints/)
* [ Catalog/Handbook ](https://www.usa.edu/catalog-handbook/)
* [ Social Media Guidelines ](https://www.usa.edu/social-media-guidelines/)
* [ Careers @ USA ](https://careers.usa.edu/)
* [ Media Resources ](https://www.usa.edu/media-resources/)
* [ State Licensure ](https://www.usa.edu/legal/state-licensure/)
© Copyright 2024 [ University of St. Augustine for Health Sciences ](/)
* [ Legal and Consumer Disclosures ](https://www.usa.edu/legal/)
* [ Title IX / Safety & Security ](/safety-security/)
* [ Privacy Policy ](https://www.usa.edu/legal/privacy-policy/)
* [ Program Data ](https://www.usa.edu/legal/program-data/)
* [ Accreditation ](/about/accreditation/)
| biology | 483319 | https://no.wikipedia.org/wiki/Washington%20University%20in%20St.%20Louis | Washington University in St. Louis | Washington University er et privat, forskningsbasert universitet i St. Louis i delstaten Missouri, USA. Det holder høyt faglig nivå, og skolepengene på US$ 35 524 var trolig de høyeste ved noe amerikansk lærested i 2006. WU ble opprettet i 1853.
Universitetet hevder at 22 nobelprisvinnere er eller har vært knyttet til lærestedet, og at ni av disse gjorde mesteparten av sitt premierte forskningsarbeid her. Utdanningene innen medisin, arkitektur og sosialt arbeid har topplasseringer på amerikanske universitetsrankinger.
Skolene, fakultetene og noen viktige institutter omfatter:
College of Arts & Sciences (1853)
Center for New Institutional Social Sciences
Richard A. Gephardt Institute for Public Service
Max Kade Center for Contemporary German Literature
Graduate School of Arts & Sciences
University College (1931)
Sam Fox School of Design & Visual Arts
College of Art
College of Architecture
Graduate School of Art
Olin Business School (1912) – 1 574 studenter
International Society for New Institutional Economics (ISNIE)
School of Engineering (1854)
Center for Application of Information Technologies (CAIT)
School of Law (1867) – 723 studenter
Center for Empirical Research in the Law
George Warren Brown School of Social Work (1925) – 458 studenter
Kathryn M. Buder Center for American Indian Studies
Center for Latino Family Research
Center for Mental Health Services Research
Center for Social Development
Graduate School of Architecture & Urban Design
School of Medicine (1891) – 1 012 studenter
Barnes-Jewish Hospital
Central Institute for the Deaf
St. Louis Children's Hospital
Rehabilitation Institute of Saint Louis
Alvin J. Siteman Cancer Center
Center for Advanced Medicine
Eric P. Newman Education Center
Ved universitetet var det 13 355 studenter og 1 076 vitenskapelig ansatte i 2006, og samme året var skolepengene US$ 35.524 for studenter folkeregistrert i Missouri. Studiene gis opp til doktorgradsnivå. Studentene kommer fra alle 50 stater og ca. 125 land utenfor USA.
Referanser
Eksterne lenker
Universiteter i Missouri
St. Louis
Utdanningsinstitusjoner etablert i 1853
1853 i USA | norwegian_bokmål | 0.79144 |
baby_memories/rottmanpnasmemoryspa.txt | Skip to main content
[  ](/)
[  ](/pittwire)
Explore Sections
* open search
* open menu
Close
From the latest big breakthrough to the most influential and inspiring figures
on campus to Pitt in the community, Pittwire is your official source for
what’s happening now.
Explore Sections
* [ Health and Wellness ](/pittwire/health-and-wellness)
* [ Technology and Science ](/pittwire/technology-and-science)
* [ Arts and Humanities ](/pittwire/arts-and-humanities)
* [ Community Impact ](/pittwire/community-impact)
* [ Diversity, Equity, and Inclusion ](/pittwire/diversity-equity-and-inclusion)
* [ Global ](/pittwire/global)
* [ Innovation and Research ](/pittwire/innovation-and-research)
* [ Our City/Our Campus ](/pittwire/our-cityour-campus)
* [ Pitt Magazine ](/pittwire/pittmagazine)
Explore By Category
* [ Features & Articles ](/pittwire/news/features-articles)
* [ Accolades & Honors ](/pittwire/news/accolades-honors)
* [ Ones to Watch ](/pittwire/news/ones-to-watch)
* [ Announcements and Updates ](/pittwire/news/announcements-and-updates)
## Pittwire Other Links
* [ Event Calendar ](https://calendar.pitt.edu/)
* [ Social Media Directory ](https://www.pitt.edu/social)
Close
Search Pitt
Search
[ Search for People ](https://find.pitt.edu)
Close
## Global Menu
* [ Apply ](https://admissions.pitt.edu/apply/)
* [ Visit ](https://admissions.pitt.edu/visit/unscripted/)
* [ Give ](https://www.giveto.pitt.edu/s/1729/18/home-giving.aspx?gid=2&pgid=2135)
* [ Pittwire ](/pittwire)
* [ Events ](http://calendar.pitt.edu/)
Navigation
Navigation
* [ About ](/about)
* [ Academics ](/academics)
* [ Admissions ](/admissions)
* [ Research ](/research)
* [ Life at Pitt ](/student-life)
* [ Athletics ](http://pittsburghpanthers.com/)
Colleges & Schools
Colleges & Schools
* [ Arts & Sciences ](https://www.as.pitt.edu)
* [ Business ](https://www.business.pitt.edu)
* [ Computing & Information ](https://www.sci.pitt.edu)
* [ Dental Medicine ](https://www.dental.pitt.edu)
* [ Education ](https://www.education.pitt.edu)
* [ Engineering ](https://www.engineering.pitt.edu)
* [ General Studies ](https://www.cgs.pitt.edu)
* [ Health & Rehabilitation ](https://www.shrs.pitt.edu)
* [ Honors College ](https://www.honors.pitt.edu)
* [ Law ](https://www.law.pitt.edu)
* [ Medicine ](https://www.medschool.pitt.edu)
* [ Nursing ](https://www.nursing.pitt.edu)
* [ Pharmacy ](https://www.pharmacy.pitt.edu)
* [ Public & Intl Affairs ](https://www.gspia.pitt.edu)
* [ Public Health ](https://publichealth.pitt.edu/)
* [ Social Work ](https://www.socialwork.pitt.edu/)
Info For
Info For
* * [ COVID-19 Response ](http://coronavirus.pitt.edu/)
* [ Alumni ](https://www.alumni.pitt.edu/s/1729/alumni/home.aspx?gid=2&pgid=2381)
* [ Community ](https://www.community.pitt.edu/)
* [ Global ](/global)
* [ Sustainability ](https://www.sustainable.pitt.edu/)
* [ __ Twitter ](https://www.twitter.com/PittTweet)
* [ __ Instagram ](https://www.instagram.com/pittofficial)
* [ __ Facebook ](https://www.facebook.com/upitt)
* [ __ Youtube ](https://www.youtube.com/user/pittweb)
Close
Search Pittwire
Search
[ Search www.pitt.edu ](https://www.pitt.edu/search-results)
Features & Articles
# The best way to retain memories may depend on the content
March 12, 2024
Tags
* Innovation and Research
* Center for Neuroscience
* [  ](https://twitter.com/intent/tweet?url=https://www.pitt.edu/pittwire/features-articles/rottman-pnas-memory-spacing&hashtags=Hashtag "Share on Twitter - opens in a new window")
* [  ](http://www.facebook.com/share.php?u=https://www.pitt.edu/pittwire/features-articles/rottman-pnas-memory-spacing&title=The best way to retain memories may depend on the content "Share on Facebook - opens in a new window")
* [  ](mailto:?subject=The best way to retain memories may depend on the content&body=Check out this site https://www.pitt.edu/pittwire/features-articles/rottman-pnas-memory-spacing "Share via Email")
## Subscribe to Pittwire Today
Get the most interesting and important stories from the University of
Pittsburgh.
[ Subscribe ](/subscribe-pittwire)
New experiments by psychologists at the University of Pittsburgh and Temple
University suggest varying what we study and spacing out our learning over
time can both be helpful for retaining memories — it just depends on what
we’re trying to remember. The work provides new insight into how we learn and
remember our real-world experiences.
“Lots of prior research has shown that learning and memory benefit from
spacing study sessions out,” said [ Benjamin Rottman
](https://www.psychology.pitt.edu/people/benjamin-m-rottman-phd) , an
associate professor of psychology and director of the Causal Learning and
Decision-Making Lab at Pitt. “For example, if you cram the night before a
test, you might remember the information the next day for the test, but you
will probably forget it fairly soon. In contrast, if you study the material on
different days leading up to the test, you will be more likely to recall it
for a longer period of time.”
This “spacing effect” is one of the most replicated findings in psychological
research, but much of that work has been predicated on the idea that what you
are trying to learn repeats identically each time. Yet that is rarely the case
in real life, when some features of our experiences may stay the same while
others are likely to change.
For example, imagine repeat trips to your local coffee shop. You might see the
same tables, seats and decorations, but a new barista may be serving you. It’s
not clear that the spacing effect would work the same way in the face of such
changes.
In two experiments, the researchers asked participants to repeatedly study
pairs of items and scenes that were either identical on each repetition or
where the item stayed the same, but the scene changed each time.
One of the experiments asked participants to learn these pairings and then
test their memory via their smartphones — an unusual approach for learning and
memory research. This enabled researchers to ask participants to learn pairs
at various times of the day across 24 hours, more accurately representing how
people actually learn information than in prior lab experiments.
In the second experiment, researchers collected data online in a single
session. The team [ published their results
](https://www.pnas.org/doi/10.1073/pnas.2311077121) in the March 12 online
edition of the Proceedings of the National Academy of Sciences.
The setup allowed the team to study the effects of memorizing both across
different timescales and the content of what’s being memorized, explained [
Emily Cowan ](https://sites.temple.edu/adaptivememorylab/people/) , lead
author on the paper and a postdoctoral fellow in Temple’s Adaptive Memory Lab.
“With this, we were able to ask how memory is impacted both by what is being
learned — whether that is an exact repetition or instead, contains variations
or changes — as well as when it is learned over repeated study opportunities.”
As in prior experiments, researchers found that spaced learning helped
participants remember the items. But they also found the participants’ memory
was better for the items that had been paired with different scenes compared
to items shown with the same scene repeatedly. For example, if you want to
remember a new person’s name, repeating the name but associating it with
different information about the person can be helpful.
On the other hand, Rottman said, stability appeared to aid the type of memory
that pairs items and scenes. “Spacing only benefited memory for the pairs that
were repeated exactly, and only if there were pretty long gaps, hours to days,
between study opportunities,” he said. “For example, if you are trying to
remember the new person’s name and something about them, like their favorite
food, it is more helpful to repeat that same exact name-food pairing multiple
times with spacing between each.”
The Pitt-Temple experiments represent basic memory research, and so the
research may not necessarily apply to some types of real-world memorizing
tasks. “Because of how nuanced memory is, it is hard to provide clear advice
for things like studying for a test because the sort of material can be so
different,” Rottman said. “But in theory our findings should be broadly
relevant to different sorts of tasks, like remembering someone’s name and
things about them, studying for a test and learning new vocabulary in a
foreign language.”
Cowan continued: “Our work suggests that both variability and spacing may
present methods to improve our memory for isolated features and associative
information, respectively, raising important applications for future research,
education and our everyday lives.”
In addition to Cowan and Rottman, study investigators included Vishnu “Deepu”
Murty, principal investigator of Temple’s Adaptive Memory Lab, and Yiwen
Zhang, a graduate student in cognitive psychology at Pitt.
_— Bruce Steele, photography by Tom Altany_
This research was funded by the U.S. National Science Foundation (grant number
1651330) and the National Institutes of Health (grant numbers NIH R21
DA043568, K01 MH111991 and R01 DA055259).
Trending
## [ Pitt is launching an Office of Sustainability in the Health Sciences
](/pittwire/features-articles/office-sustainability-health-sciences-launch)
## [ Here are the speakers for Pitt’s graduate school commencement ceremonies
](/pittwire/features-articles/2024-graduate-commencement-speakers)
## [ Help shape Pitt IT’s 10-Year Horizon Plan ](/pittwire/announcements-and-
updates/shape-10-year-it-plan)
[  ](/
"University of Pittsburgh")
## Global Menu
* [ Apply ](https://admissions.pitt.edu/apply/)
* [ Visit ](https://admissions.pitt.edu/visit/unscripted/)
* [ Give ](https://www.giveto.pitt.edu/s/1729/18/home-giving.aspx?gid=2&pgid=2135)
* [ Pittwire ](/pittwire)
* [ Events ](http://calendar.pitt.edu/)
* [ About ](/about)
* [ Academics ](/academics)
* [ Admissions ](/admissions)
* [ Research ](/research)
* [ Life at Pitt ](/student-life)
* [ Athletics ](http://pittsburghpanthers.com/)
Quick Links & Resources
Quick Links & Resources
* [ Accessibility Statement ](https://www.diversity.pitt.edu/accessibility-statement)
* [ Advising at Pitt ](https://www.personaled.pitt.edu/mentoring-advising/advising-pitt)
* [ Careers ](https://www.join.pitt.edu/)
* [ Consumer Info/Achievement ](/about/general-info)
* [ Contact Us ](/contact)
* [ COVID-19 Response ](http://coronavirus.pitt.edu/)
* [ Departments A-Z ](https://www.academics.pitt.edu/programs/a-z)
* [ Diversity, Equity and Inclusion ](https://www.diversity.pitt.edu/)
* [ Find People ](https://find.pitt.edu/)
* [ Information Technology ](https://www.technology.pitt.edu/)
* [ LGBTQ+ ](https://www.lgbtq.pitt.edu/)
* [ Nondiscrimination and Anti-Harassment Policy ](https://www.diversity.pitt.edu/notice-nondiscrimination-and-anti-harassment-policy-statement)
* [ Privacy Policy ](https://www.pitt.edu/privacy-policy)
* [ My Pitt ](http://my.pitt.edu)
Regional Campuses
Regional Campuses
* [ Bradford ](https://upb.pitt.edu/)
* [ Greensburg ](http://www.greensburg.pitt.edu/)
* [ Johnstown ](https://www.johnstown.pitt.edu/)
* [ Titusville ](https://www.titusville.pitt.edu/)
Colleges & Schools
Colleges & Schools
* [ Arts & Sciences ](https://www.as.pitt.edu)
* [ Business ](https://www.business.pitt.edu)
* [ Computing & Information ](https://www.sci.pitt.edu)
* [ Dental Medicine ](https://www.dental.pitt.edu)
* [ Education ](https://www.education.pitt.edu)
* [ Engineering ](https://www.engineering.pitt.edu)
* [ General Studies ](https://www.cgs.pitt.edu)
* [ Health & Rehabilitation ](https://www.shrs.pitt.edu)
* [ Honors College ](https://www.honors.pitt.edu)
* [ Law ](https://www.law.pitt.edu)
* [ Medicine ](https://www.medschool.pitt.edu)
* [ Nursing ](https://www.nursing.pitt.edu)
* [ Pharmacy ](https://www.pharmacy.pitt.edu)
* [ Public & Intl Affairs ](https://www.gspia.pitt.edu)
* [ Public Health ](https://publichealth.pitt.edu/)
* [ Social Work ](https://www.socialwork.pitt.edu/)
4200 Fifth Ave.
Pittsburgh , PA 15260
United States
[ +1 412-624-4141 ](tel:+1-412-624-4141)
* [ __ Twitter ](https://www.twitter.com/PittTweet)
* [ __ Instagram ](https://www.instagram.com/pittofficial)
* [ __ Facebook ](https://www.facebook.com/upitt)
* [ __ Youtube ](https://www.youtube.com/user/pittweb)
| biology | 2973281 | https://sv.wikipedia.org/wiki/Pitthea | Pitthea | Pitthea är ett släkte av fjärilar. Pitthea ingår i familjen mätare.
Dottertaxa till Pitthea, i alfabetisk ordning
Pitthea abbreviata
Pitthea agenoria
Pitthea albolineata
Pitthea argentiplaga
Pitthea aurantifascia
Pitthea bifasciola
Pitthea caesarea
Pitthea catadela
Pitthea continua
Pitthea cryptochroma
Pitthea cunaxa
Pitthea cyanomeris
Pitthea decisa
Pitthea eximia
Pitthea expandens
Pitthea famula
Pitthea famulita
Pitthea flavimargo
Pitthea flavipicta
Pitthea fractimacula
Pitthea fuliginosa
Pitthea lacunata
Pitthea lynckerii
Pitthea mungi
Pitthea neavi
Pitthea perspicua
Pitthea pypomima
Pitthea rubriplaga
Pitthea sanguiflua
Pitthea sospes
Pitthea subflaveola
Pitthea syndroma
Pitthea tamsi
Pitthea trifasciata
Pitthea triplagiata
Pitthea türckheimia
Bildgalleri
Källor
Externa länkar
Mätare
Pitthea | swedish | 1.246607 |
sexual_repro_outside/Ursusarctos.txt | # [ Animal Diversity Web ](/)
[ University of Michigan Museum of Zoology ](https://lsa.umich.edu/ummz/) [
University of Michigan ](https://www.umich.edu/)
* [ Home ](/)
* [ About Us ](/about/)
* [ About Animal Names ](/animal_names/)
* [ Educational Resources ](/teach/)
* [ Special Collections ](/collections/)
* [ Glossary ](/glossary/)
* [ Browse Animalia ](/accounts/Animalia/)
## More Information
### Additional Information
* [ BioKIDS Critter Catalog ](http://www.biokids.umich.edu/critters/Ursus_arctos/)
* [ Encyclopedia of Life ](http://eol.org/search/?q=Ursus arctos&search=Go)
## Ursus arctos brown bear
Facebook
Twitter
* [  ](/accounts/Ursus_arctos/pictures/collections/contributors/david_blank/brownbear/)
* [  ](/accounts/Ursus_arctos/pictures/collections/contributors/phil_myers/ADW_mammals/Carnivora/Ursidae/grizzley2495/)
* [  ](/accounts/Ursus_arctos/pictures/collections/contributors/usfws/brownbear2/)
* [  ](/accounts/Ursus_arctos/pictures/collections/contributors/david_blank/brownbear5/)
* [  ](/accounts/Ursus_arctos/pictures/collections/contributors/david_blank/brownbear2/)
By Tanya Dewey and Liz Ballenger
* Geographic Range
* Habitat
* Physical Description
* Reproduction
* Lifespan/Longevity
* Behavior
* Communication and Perception
* Food Habits
* Predation
* Ecosystem Roles
* Economic Importance for Humans: Positive
* Economic Importance for Humans: Negative
* Conservation Status
* Contributors
* References
### Geographic Range
Ursus arctos once ranged throughout northern and central Europe, Asia, the
Atlas mountains of Morocco and Algeria, and western North America as far south
as Mexico. They are now found in extremely small numbers from western Europe
and Palestine to eastern Siberia and the Himalayan region, possibly the Atlas
Mountains of northwest Africa, and Hokkaido. Northern North American
populations in Alaska and western Canada remain fairly stable. Many
populations in the United States have been extirpated, including those of the
Sierra Nevada and southern Rockies. Northern Mexican populations were
extirpated in the 1960's. ( Wilson and Ruff, 1999 )
* Biogeographic Regions
* nearctic
* native
* palearctic
* native
* Other Geographic Terms
* holarctic
### Habitat
Brown bears occupy a variety of habitats, from desert edges to high mountain
forests and ice fields. In North America they seem to prefer open areas such
as tundra, alpine meadows, and coastlines. Historically, they were common on
the Great Plains prior to the arrival of European settlers. In Siberia, Ursus
arctos occurs primarily in forests, while European populations are restricted
mainly to mountain woodlands. The main habitat requirement for Ursus arctos
is some area with dense cover in which it can shelter by day. ( Wilson and
Ruff, 1999 )
* Habitat Regions
* temperate
* terrestrial
* Terrestrial Biomes
* tundra
* taiga
* desert or dune
* savanna or grassland
* chaparral
* forest
* scrub forest
* mountains
### Physical Description
One of the largest of living carnivores, grizzly bears are 1 to 2.8 meters in
length from head to rump and their tails are 65 to 210 mm long. They are 90 to
150 cm tall at the shoulder and can tower at an intimidating height of 8 feet
when standing upright on their hind legs. They range in weight from 80 to more
than 600 kg. On average, adult males are 8 to 10% larger than females. Ursus
arctos is largest along the the coast of southern Alaska and on nearby
islands where males average 389 kg and females average 207 kg, though some
males have been weighed at as much as 780 kg. Distance between the canines is
from 6 to 8 cm. Size rapidly declines to the north and east, with individuals
in southwestern Yukon weighing only 140 kg on average. Fur is usually dark
brown, but varies from cream to almost black. Individuals in the Rocky
Mountains have long hairs along the shoulders and back which are frosted with
white, giving a grizzled appearance, hence the common name grizzly bear in
that region. Brown bears are extremely strong and have good endurance; they
can kill a cow with one blow, outrun a horse, outswim an Olympian, and drag a
dead elk uphill. ( Wilson and Ruff, 1999 )
* Other Physical Features
* endothermic
* heterothermic
* homoiothermic
* bilateral symmetry
* Sexual Dimorphism
* male larger
* Range mass
80 to 600 kg
176.21 to 1321.59 lb
* Range length
1 to 2.8 m
3.28 to 9.19 ft
### Reproduction
Female brown bears copulate with multiple males during estrus, which lasts 10
to 30 days. Males may fight over females and guard them for 1 to 3 weeks.
Female receptivity is probably communicated by scent marking throughout her
territory. ( Wilson and Ruff, 1999 )
* Mating System
* polygynandrous (promiscuous)
Mating of brown bears takes place from May to July. Fertilized eggs develop to
the blastocyst stage, after which implantation in the uterus is delayed. The
blastocyst becomes implanted approximately 5 months after mating, usually in
November when the female has entered her winter sleep. A 6 to 8 week gestation
follows, with births occurring from January to March (usually while the female
is still in hibernation). Total gestation time, including pre-implantation,
ranges from 180 to 266 days. Females remain in estrus throughout the breeding
season until mating occurs and do not ovulate again for at least 2 (usually 3
or 4) years after giving birth. Two to three offspring are generally born per
litter.
Brown bears mature sexually between 4-6 years of age, but continue growing
until 10-11 years old. Bears have been known to live and reproduce in
Yellowstone Park at 25 years of age, and potential lifespan in captivity is as
great as 50 years. ( Wilson and Ruff, 1999 )
* Key Reproductive Features
* iteroparous
* seasonal breeding
* gonochoric/gonochoristic/dioecious (sexes separate)
* sexual
* viviparous
* delayed implantation
* Breeding interval
Brown bear females typically breed every 2 to 4 years.
* Breeding season
Breeding occurs from May to July.
* Range number of offspring
3 (high)
* Average number of offspring
2
* Average number of offspring
2
[ AnAge ](http://genomics.senescence.info/species/entry.php?species=Ursus_arctos)
* Range gestation period
180 to 266 days
* Range weaning age
18 to 30 months
* Range time to independence
2 to 3 years
* Range age at sexual or reproductive maturity (female)
4 to 6 years
* Range age at sexual or reproductive maturity (male)
4 to 6 years
Young are born blind, helpless, and naked, weighing only 340 to 680 grams. By
3 months old cubs weigh about 15 kg, by 6 months weight averages 25 kg.
Lactation continues for 18 to 30 months, although the cubs are eating a wide
variety of foods by about 5 months of age. Cubs remain with the mother until
at least their second spring of life (usually until the third or fourth). Male
brown bears do not contribute parental care. ( Wilson and Ruff, 1999 )
* Parental Investment
* no parental involvement
* altricial
* pre-fertilization
* protecting
* female
* pre-hatching/birth
* provisioning
* female
* protecting
* female
* pre-weaning/fledging
* provisioning
* female
* protecting
* female
* pre-independence
* provisioning
* female
* protecting
* female
* extended period of juvenile learning
### Lifespan/Longevity
Brown bears in the wild can live for 20 to 30 years, although most brown bears
die in their first few years of life. In captivity, brown bears have been
known to live up to 50 years. ( Wilson and Ruff, 1999 )
* Range lifespan
Status: captivity
50 (high) years
* Typical lifespan
Status: wild
20 to 30 years
* Average lifespan
Status: captivity
50.0 years
[ Max Planck Institute for Demographic Research ](http://www.demogr.mpg.de//cgi-bin/longevityrecords/reference.plx?data=370)
* Average lifespan
Status: captivity
47.0 years
[ Max Planck Institute for Demographic Research ](http://www.demogr.mpg.de//cgi-bin/longevityrecords/reference.plx?data=371)
### Behavior
Ursus arctos individuals may be active at any time of the day, but generally
forage in the morning and evening and rest in dense cover by day. Brown bears
may excavate shallow depressions in which to lie. Seasonal movements of Ursus
arctos have been observed, with individuals sometimes traveling hundreds of
kilometers during the autumn to reach areas of favorable food supplies, such
as salmon streams and areas of high berry production.
Home ranges overlap extensively and there is no evidence of territorial
defense, although bears are generally solitary. Occasionally, bears may gather
in large numbers at major food sources and form family foraging groups with
more than one age class of young. Under these conditions, dominance
hierarchies are usually formed and maintained with aggression. Highest-ranking
individuals are large adult males, although the most aggressive bears are
females with young. Least aggressive and lowest-ranking are adolescents. The
only social bonds formed are between females and young.
Brown bears begin a period of inactivity in October to December, and resume
activity in March to May, with the exact period dependent on the location,
weather, and condition of the individual. In southern areas, this period of
inactivity is very brief or may not occur at all. This period is marked by a
deep sleep in which these bears allow their body temperature to drop by a few
degrees. It is not true hibernation and bears can generally be aroused readily
from their winter sleep.
Most often, brown bears dig their own dens and make a bed out of dry
vegetation. Burrows are usually located on a sheltered slope, either under a
large stone or among the roots of a mature tree. Dens are sometimes used
repeatedly year after year.
Ursus arctos moves with a slow, lumbering walk, although it is capable of
moving very quickly and can easily catch a black bear. Brown bears are mainly
terrestrial, although they can often be found swimming or preying upon fish in
the water. Adults are unable to climb trees. ( Wilson and Ruff, 1999 )
* Key Behaviors
* terricolous
* crepuscular
* motile
* nomadic
* migratory
* hibernation
* solitary
* territorial
#### Home Range
Home ranges can be as large as 2,600 sq km, but are on average between 73 and
414 sq km, with male ranges nearly 7 times greater than female ranges. Home
ranges overlap extensively.
### Communication and Perception
Brown bears communicate primarily through smells and sounds. Brown bears can
be heard making moaning noises sometimes while they are foraging. They scratch
and rub on trees and other landmarks to communicate territorial boundaries and
reproductive status. ( Wilson and Ruff, 1999 )
Brown bears have an excellent sense of smell (able to follow the scent of a
rotting carcass for more than two miles), human-level hearing, but relatively
poor eyesight. ( Wilson and Ruff, 1999 )
* Communication Channels
* tactile
* acoustic
* chemical
* Perception Channels
* visual
* tactile
* acoustic
* chemical
### Food Habits
Brown bears are omnivorous, eating almost anything nutritious. Their diet
changes with seasonal availability of different food sources. They eat a wide
variety of plant foods, including grasses, sedges, roots, moss, and bulbs.
Fruits, nuts, berries, bulbs, and tubers are taken extensively during summer
and early autumn. They consume insects, fungi, and roots at all times of the
year and also dig mice, ground squirrels, marmots, and other fossorial animals
out of their burrows. Moth larvae have been demonstrated to be especially
important sources of protein and fat when brown bears are putting on fat in
the fall. In the Canadian Rockies and other areas, grizzly bears (the
subspecies of brown bear in that area) are quite carnivorous, hunting moose,
elk, mountain sheep, and mountain goats. Occasionally black bears are preyed
upon. In Alaska, brown bears have been observed to eat carrion and
occasionally capture young calves of caribou and moose. Brown bears have also
been observed to feed on vulnerable populations of breeding salmon in the
summer in these areas. ( Wilson and Ruff, 1999 )
* Primary Diet
* omnivore
* Animal Foods
* mammals
* fish
* carrion
* insects
* Plant Foods
* leaves
* roots and tubers
* seeds, grains, and nuts
* fruit
* bryophytes
* Other Foods
* fungus
### Predation
Because of their size and aggressiveness towards threats, brown bears are not
often preyed upon. Humans have persecuted them throughout recent history and
some cubs may be attacked by other bears or by mountain lions or wolves,
although this is very rare. ( Wilson and Ruff, 1999 )
* Anti-predator Adaptations
* cryptic
* Known Predators
* humans ( [ Homo sapiens ](/accounts/Homo_sapiens/) )
* other brown bears ( Ursus arctos )
* wolves ( [ Canis lupus ](/accounts/Canis_lupus/) )
* mountain lions ( [ Puma concolor ](/accounts/Puma_concolor/) )
### Ecosystem Roles
Brown bears are important predators and seed dispersers in the ecosystems in
which they live.
### Economic Importance for Humans: Positive
Brown bears have been widely sought as big game trophies and are currently
subject to regulated sport hunting throughout much of their range. Once brown
bears were used for their meat and hides but these products are not currently
in high commercial demand. Some bear body parts (such as gall bladders) bring
high prices on the traditional Asian medicine market, although no true
medicinal benefit of these parts has ever been documented.
Currently, brown bears help to fuel an ecotourism industry, especially in
areas such as Yellowstone National Park, Wyoming and parts of Alaska. (
Wilson and Ruff, 1999 )
* Positive Impacts
* body parts are source of valuable material
* ecotourism
### Economic Importance for Humans: Negative
Brown bears have been long considered the most dangerous animal in North
America, although real danger of attack from this animal is often exaggerated.
In general, brown bears attempt to avoid human contact and will not attack
unless startled at close quarters with young or engrossed in a search for
food. They are unpredictable in temperament, however, and often exhibit
impulsive and petulant behavior.
Brown bears have been persecuted extensively as predators of domestic
livestock, especially cattle and sheep, although their actual impact on the
livestock industry is probably negligible. ( Wilson and Ruff, 1999 )
* Negative Impacts
* injures humans
* bites or stings
### Conservation Status
Their conservation status depends on the population. Some populations are
clearly endangered, others are not. Brown bear numbers have dropped
dramatically since the turn of the century, when settlers and livestock
flooded the West, driving these bears out of much of their former range. Brown
bears now cling to a mere 2 per cent of their former range. Logging, mining,
road construction, resorts, subdivisions, golf courses, etc. have all
encroached on suitable bear habitat, resulting in a decrease in bear numbers.
Brown bear numbers were estimated at 100,000 in the conterminous United States
in the early 1900's, but there are now fewer than 1,000. Brown bears are still
fairly common in the mountainous regions of western Canada and Alaska, perhaps
numbering about 30,000 individuals. In Eurasia there are an estimated 100,000
brown bears, with about 70,000 of those living in the Soviet Union. However,
habitat destruction and persecution threaten brown bears throughout their
range. A growing market in bear products for the Asian market, despite a
complete lack of evidence that products made from bear parts have any medical
value, threatens bear species throughout Eurasia and western North America. (
Wilson and Ruff, 1999 )
* [ IUCN Red List ](http://www.iucnredlist.org/)
Least Concern
[ More information ](http://www.iucnredlist.org/apps/redlist/details/41688)
* [ IUCN Red List ](http://www.iucnredlist.org/)
Least Concern
[ More information ](http://www.iucnredlist.org/apps/redlist/details/41688)
* [ US Federal List ](http://www.fws.gov/endangered/)
Endangered
* [ CITES ](http://www.cites.org/eng/app/appendices.php)
Appendix I
### Contributors
Tanya Dewey (author), Animal Diversity Web.
Liz Ballenger (author), University of Michigan-Ann Arbor.
### Glossary
Nearctic
living in the Nearctic biogeographic province, the northern part of the New
World. This includes Greenland, the Canadian Arctic islands, and all of the
North American as far south as the highlands of central Mexico.
Palearctic
living in the northern part of the Old World. In otherwords, Europe and Asia
and northern Africa.
acoustic
uses sound to communicate
altricial
young are born in a relatively underdeveloped state; they are unable to feed
or care for themselves or locomote independently for a period of time after
birth/hatching. In birds, naked and helpless after hatching.
bilateral symmetry
having body symmetry such that the animal can be divided in one plane into two
mirror-image halves. Animals with bilateral symmetry have dorsal and ventral
sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
carrion
flesh of dead animals.
chaparral
Found in coastal areas between 30 and 40 degrees latitude, in areas with a
Mediterranean climate. Vegetation is dominated by stands of dense, spiny
shrubs with tough (hard or waxy) evergreen leaves. May be maintained by
periodic fire. In South America it includes the scrub ecotone between forest
and paramo.
chemical
uses smells or other chemicals to communicate
crepuscular
active at dawn and dusk
cryptic
having markings, coloration, shapes, or other features that cause an animal to
be camouflaged in its natural environment; being difficult to see or otherwise
detect.
delayed implantation
in mammals, a condition in which a fertilized egg reaches the uterus but
delays its implantation in the uterine lining, sometimes for several months.
desert or dunes
in deserts low (less than 30 cm per year) and unpredictable rainfall results
in landscapes dominated by plants and animals adapted to aridity. Vegetation
is typically sparse, though spectacular blooms may occur following rain.
Deserts can be cold or warm and daily temperates typically fluctuate. In dune
areas vegetation is also sparse and conditions are dry. This is because sand
does not hold water well so little is available to plants. In dunes near seas
and oceans this is compounded by the influence of salt in the air and soil.
Salt limits the ability of plants to take up water through their roots.
ecotourism
humans benefit economically by promoting tourism that focuses on the
appreciation of natural areas or animals. Ecotourism implies that there are
existing programs that profit from the appreciation of natural areas or
animals.
endothermic
animals that use metabolically generated heat to regulate body temperature
independently of ambient temperature. Endothermy is a synapomorphy of the
Mammalia, although it may have arisen in a (now extinct) synapsid ancestor;
the fossil record does not distinguish these possibilities. Convergent in
birds.
forest
forest biomes are dominated by trees, otherwise forest biomes can vary widely
in amount of precipitation and seasonality.
heterothermic
having a body temperature that fluctuates with that of the immediate
environment; having no mechanism or a poorly developed mechanism for
regulating internal body temperature.
hibernation
the state that some animals enter during winter in which normal physiological
processes are significantly reduced, thus lowering the animal's energy
requirements. The act or condition of passing winter in a torpid or resting
state, typically involving the abandonment of homoiothermy in mammals.
holarctic
a distribution that more or less circles the Arctic, so occurring in both the
Nearctic and Palearctic biogeographic regions.
Found in northern North America and northern Europe or Asia.
iteroparous
offspring are produced in more than one group (litters, clutches, etc.) and
across multiple seasons (or other periods hospitable to reproduction).
Iteroparous animals must, by definition, survive over multiple seasons (or
periodic condition changes).
migratory
makes seasonal movements between breeding and wintering grounds
motile
having the capacity to move from one place to another.
mountains
This terrestrial biome includes summits of high mountains, either without
vegetation or covered by low, tundra-like vegetation.
native range
the area in which the animal is naturally found, the region in which it is
endemic.
nomadic
generally wanders from place to place, usually within a well-defined range.
omnivore
an animal that mainly eats all kinds of things, including plants and animals
polygynandrous
the kind of polygamy in which a female pairs with several males, each of which
also pairs with several different females.
scrub forest
scrub forests develop in areas that experience dry seasons.
seasonal breeding
breeding is confined to a particular season
sexual
reproduction that includes combining the genetic contribution of two
individuals, a male and a female
solitary
lives alone
tactile
uses touch to communicate
taiga
Coniferous or boreal forest, located in a band across northern North America,
Europe, and Asia. This terrestrial biome also occurs at high elevations. Long,
cold winters and short, wet summers. Few species of trees are present; these
are primarily conifers that grow in dense stands with little undergrowth. Some
deciduous trees also may be present.
temperate
that region of the Earth between 23.5 degrees North and 60 degrees North
(between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees
South and 60 degrees South (between the Tropic of Capricorn and the Antarctic
Circle).
terrestrial
Living on the ground.
territorial
defends an area within the home range, occupied by a single animals or group
of animals of the same species and held through overt defense, display, or
advertisement
tropical savanna and grassland
A terrestrial biome. Savannas are grasslands with scattered individual trees
that do not form a closed canopy. Extensive savannas are found in parts of
subtropical and tropical Africa and South America, and in Australia.
savanna
A grassland with scattered trees or scattered clumps of trees, a type of
community intermediate between grassland and forest. See also Tropical savanna
and grassland biome.
temperate grassland
A terrestrial biome found in temperate latitudes (>23.5° N or S latitude).
Vegetation is made up mostly of grasses, the height and species diversity of
which depend largely on the amount of moisture available. Fire and grazing are
important in the long-term maintenance of grasslands.
tundra
A terrestrial biome with low, shrubby or mat-like vegetation found at
extremely high latitudes or elevations, near the limit of plant growth. Soils
usually subject to permafrost. Plant diversity is typically low and the
growing season is short.
visual
uses sight to communicate
viviparous
reproduction in which fertilization and development take place within the
female body and the developing embryo derives nourishment from the female.
### References
Allen, T.B., ed. 1979. Wild Animals of North America. The National Geographic
Society, Washington, D.C.
Nowak, R.M. and J.L Paradiso. 1983. Walker's Mammals of the World. 4th
edition. John Hopkins University Press, Baltimore, MD.
Tubarek, G. 1993. Survivors in the Shadows: Threatened and Endangered Mammals
of the American West. Northland Publishing Company, Flaggstaff, Arizona.
Wilson, D., S. Ruff. 1999. The Smithsonian Book of North American Mammals .
Washington: Smithsonian Institution Press.
[ __ ADW Pocket Guides on the iOS App Store!
](https://itunes.apple.com/us/app/adw-pocket-guide/id916179421?mt=8)
The Animal Diversity Web team is excited to announce ADW Pocket Guides!
[ Read more... ](/news/5009059054038197651/)
## Search
Enter search text __ Search
Search in feature Taxon Information Contributor Galleries Topics
Classification
* [ Explore Data @ Quaardvark ](https://animaldiversity.ummz.umich.edu/quaardvark/)
* [ Search Guide ](/search_guide/)
## Navigation Links
[ Information ](/accounts/Ursus_arctos/)
[ Pictures ](/accounts/Ursus_arctos/pictures/)
[ Specimens ](/accounts/Ursus_arctos/specimens/)
[ Classification ](/accounts/Ursus_arctos/classification/#Ursus_arctos)
### Classification
* Kingdom [ Animalia ](/accounts/Animalia/) animals
[ Animalia: information (1) ](/accounts/Animalia/) [ Animalia: pictures
(22861) ](/accounts/Animalia/pictures/) [ Animalia: specimens (7109)
](/accounts/Animalia/specimens/) [ Animalia: sounds (722)
](/accounts/Animalia/sounds/) [ Animalia: maps (42)
](/accounts/Animalia/maps/)
* Phylum [ Chordata ](/accounts/Chordata/) chordates
[ Chordata: information (1) ](/accounts/Chordata/) [ Chordata: pictures
(15213) ](/accounts/Chordata/pictures/) [ Chordata: specimens (6829)
](/accounts/Chordata/specimens/) [ Chordata: sounds (709)
](/accounts/Chordata/sounds/)
* Subphylum [ Vertebrata ](/accounts/Vertebrata/) vertebrates
[ Vertebrata: information (1) ](/accounts/Vertebrata/) [ Vertebrata: pictures
(15168) ](/accounts/Vertebrata/pictures/) [ Vertebrata: specimens (6827)
](/accounts/Vertebrata/specimens/) [ Vertebrata: sounds (709)
](/accounts/Vertebrata/sounds/)
* Class [ Mammalia ](/accounts/Mammalia/) mammals
[ Mammalia: information (1) ](/accounts/Mammalia/) [ Mammalia: pictures (4389)
](/accounts/Mammalia/pictures/) [ Mammalia: specimens (6622)
](/accounts/Mammalia/specimens/) [ Mammalia: sounds (13)
](/accounts/Mammalia/sounds/)
* Order [ Carnivora ](/accounts/Carnivora/) carnivores
[ Carnivora: information (1) ](/accounts/Carnivora/) [ Carnivora: pictures
(963) ](/accounts/Carnivora/pictures/) [ Carnivora: specimens (1208)
](/accounts/Carnivora/specimens/) [ Carnivora: sounds (4)
](/accounts/Carnivora/sounds/)
* Family [ Ursidae ](/accounts/Ursidae/) bears
[ Ursidae: information (1) ](/accounts/Ursidae/) [ Ursidae: pictures (97)
](/accounts/Ursidae/pictures/) [ Ursidae: specimens (43)
](/accounts/Ursidae/specimens/)
* Genus [ Ursus ](/accounts/Ursus/) black bears, brown bear, and polar bear
[ Ursus: pictures (64) ](/accounts/Ursus/pictures/) [ Ursus: specimens (28)
](/accounts/Ursus/specimens/)
* Species [ Ursus arctos ](/accounts/Ursus_arctos/) brown bear
[ Ursus arctos: information (1) ](/accounts/Ursus_arctos/) [ Ursus arctos:
pictures (18) ](/accounts/Ursus_arctos/pictures/) [ Ursus arctos: specimens
(12) ](/accounts/Ursus_arctos/specimens/)
To cite this page: Ballenger, L. 2002. "Ursus arctos" (On-line), Animal
Diversity Web. Accessed April 29, 2024 at
https://animaldiversity.org/accounts/Ursus_arctos/
**Disclaimer:** The Animal Diversity Web is an educational resource **written
largely by and for college students** . ADW doesn't cover all species in the
world, nor does it include all the latest scientific information about
organisms we describe. Though we edit our accounts for accuracy, we cannot
guarantee all information in those accounts. While ADW staff and contributors
provide references to books and websites that we believe are reputable, we
cannot necessarily endorse the contents of references beyond our control.
* [ U-M Gateway ](https://www.umich.edu/) | [ U-M Museum of Zoology ](https://lsa.umich.edu/ummz/)
* [ U-M Ecology and Evolutionary Biology ](https://lsa.umich.edu/eeb/)
* © 2020 Regents of the University of Michigan
* [ Report Error ](/feedback/error_form/) / [ Comment ](/feedback/comment_form/)
This material is based upon work supported by the [ National Science
Foundation ](https://nsf.gov) Grants DRL 0089283, DRL 0628151, DUE 0633095,
DRL 0918590, and DUE 1122742. Additional support has come from the Marisla
Foundation, UM College of Literature, Science, and the Arts, Museum of
Zoology, and Information and Technology Services.
The ADW Team gratefully acknowledges their support.
| biology | 1024655 | https://sv.wikipedia.org/wiki/Leadbeaters%20falanger | Leadbeaters falanger | Leadbeaters falanger (Gymnobelideus leadbeateri) är ett pungdjur som tillhör familjen flygpungekorrar. Trots släktskapet saknar den flygförmåga. Djuret påminner mer om vanliga ekorrar.
Djurets namn syftar på John Leadbeater, en biolog som sysslade med taxonomi vid Museum of Victoria.
Utbredning
Arten förekommer i ett mindre 3 500 km² stort området i östra delen av den australiska delstaten Victoria.
Utseende
Pälsen är på ovansidan gråbrun och har en svart längsgående strimma, undersidan är ljusare till gulaktig. Ytterligare två strimmor finns i ansiktet från ögonen till öronen. Djuret når en kroppslängd mellan 15 och 17 centimeter samt en vikt mellan 120 och 165 gram. Därtill kommer en yvig svans på omkring 20 centimeters längd som inte är en gripsvans. Arten har korta klor vid varje tå och honans pung (marsupium) är väl utvecklad.
Ekologi
Leadbeaters falanger är aktiv på natten och lever i träd. Habitatet utgörs av kyliga fuktiga skogar upp till 1 500 meter över havet. Bon där de föder ungar byggs ofta i eukalyptusträd med håligheter och ligger vanligen 10 till 30 meter över marken.
Individerna lever i små grupper som vanligen består av en vuxen hona, en till tre hannar och deras ungar. Varje grupp har ett revir som är en till två hektar stort. Hos Leadbeaters falanger är honor det dominanta könet, alfahonan försvarar territoriet mot andra honor och parar sig bara med en av de könsmogna hannarna. Hannar är mindre aggressiva mot artfränder av samma kön.
Föda
Födan utgörs främst av insekter och trädens vätskor. De äter bland annat skalbaggar, spindlar och andra leddjur men gnager även på akacieträdens bark för att komma åt bastskiktet och kåda.
Fortplantning
Med undantag av de hetaste sommarmånaderna (januari, februari) kan honor para sig hela året. Dräktigheten är med 15 till 17 dagar ganska kortvarig (även för pungdjur). Per kull föds vanligen ett eller två ungdjur. Efter födelsen lever ungarna tre månader i pungen. Sedan stannar de 5 till 40 dagar i gruppens bo och deltar i utflykter. Efter 10 till 15 månader sluter honan att ge di och efter cirka två år är ungarna könsmogna. Livslängden i naturen kan vara 7,5 år och med människans vård upp till 9 år.
Leadbeaters falanger och människor
Arten upptäcktes för första gången under 1800-talet nära Melbourne. Efter 1909 registrerades en längre tid inga iakttagelser och därför antogs att djuret är utdött men 1961 upptäcktes arten igen.
På grund av arten krav på eukalyptusträd med håligheter är de känsliga för människans inverkning. Flera träd röjs eller förstörs under skogsbränder. Dessutom tar det 150 år innan ett nytt eukalyptusträd är tillräckligt stort.
Enligt uppskattningar finns bara 5000 individer kvar och det befaras att beståndet minskar ytterligare. IUCN listar arten som starkt hotad (endangered).
Referenser
Noter
Tryckta källor
Macdonald, David W. (red.), (1984) Jordens Djur 5: Pungdjuren, fladdermössen, insektätarna m.fl.. Stockholm: Bonnier Fakta. s. 130,
Ronald M. Nowak: Walker’s Mammals of the World. Johns Hopkins University Press, Baltimore/London 1999.
Externa länkar
Fåframtandade pungdjur
Däggdjur i australiska regionen | swedish | 0.807001 |
sexual_repro_outside/Reproductive_isolation.txt | The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation. They prevent members of different species from producing offspring, or ensure that any offspring are sterile. These barriers maintain the integrity of a species by reducing gene flow between related species.
The mechanisms of reproductive isolation have been classified in a number of ways. Zoologist Ernst Mayr classified the mechanisms of reproductive isolation in two broad categories: pre-zygotic for those that act before fertilization (or before mating in the case of animals) and post-zygotic for those that act after it. The mechanisms are genetically controlled and can appear in species whose geographic distributions overlap (sympatric speciation) or are separate (allopatric speciation).
Pre-zygotic isolation[edit]
Pre-zygotic isolation mechanisms are the most economic in terms of the natural selection of a population, as resources are not wasted on the production of a descendant that is weak, non-viable or sterile. These mechanisms include physiological or systemic barriers to fertilization.
Temporal or habitat isolation[edit]
See also: Allochronic speciation
The Central Valley in California prevents the two salamander populations from interacting with each other which is an example of habitat isolation. After many generations the two salamander gene pools will become mutated caused by natural selection. The mutation will change the DNA sequence of the two populations enough that the salamander populations can no longer successfully breed between each other making the populations of salamander become classified as different species.
Any of the factors that prevent potentially fertile individuals from meeting will reproductively isolate the members of distinct species. The types of barriers that can cause this isolation include: different habitats, physical barriers, and a difference in the time of sexual maturity or flowering.
An example of the ecological or habitat differences that impede the meeting of potential pairs occurs in two fish species of the family Gasterosteidae (sticklebacks). One species lives all year round in fresh water, mainly in small streams. The other species lives in the sea during winter, but in spring and summer individuals migrate to river estuaries to reproduce. The members of the two populations are reproductively isolated due to their adaptations to distinct salt concentrations.
An example of reproductive isolation due to differences in the mating season are found in the toad species Bufo americanus and Bufo fowleri. The members of these species can be successfully crossed in the laboratory producing healthy, fertile hybrids. However, mating does not occur in the wild even though the geographical distribution of the two species overlaps. The reason for the absence of inter-species mating is that B. americanus mates in early summer and B. fowleri in late summer.
Certain plant species, such as Tradescantia canaliculata and T. subaspera, are sympatric throughout their geographic distribution, yet they are reproductively isolated as they flower at different times of the year. In addition, one species grows in sunny areas and the other in deeply shaded areas.
Behavioral isolation[edit]
The different mating rituals of animal species creates extremely powerful reproductive barriers, termed sexual or behavior isolation, that isolate apparently similar species in the majority of the groups of the animal kingdom. In dioecious species, males and females have to search for a partner, be in proximity to each other, carry out the complex mating rituals and finally copulate or release their gametes into the environment in order to breed.
The songs of birds, insects and many other animals are part of a ritual to attract potential partners of their own species. The song presents specific patterns recognizable only by members of the same species, and therefore represents a mechanism of reproductive isolation. This recording is the song of a species of cicada, recorded in New Zealand.
Mating dances, the songs of males to attract females or the mutual grooming of pairs, are all examples of typical courtship behavior that allows both recognition and reproductive isolation. This is because each of the stages of courtship depend on the behavior of the partner. The male will only move onto the second stage of the exhibition if the female shows certain responses in her behavior. He will only pass onto the third stage when she displays a second key behavior. The behaviors of both interlink, are synchronized in time and lead finally to copulation or the liberation of gametes into the environment. No animal that is not physiologically suitable for fertilization can complete this demanding chain of behavior. In fact, the smallest difference in the courting patterns of two species is enough to prevent mating (for example, a specific song pattern acts as an isolation mechanism in distinct species of grasshopper of the genus Chorthippus).
Even where there are minimal morphological differences between species, differences in behavior can be enough to prevent mating. For example, Drosophila melanogaster and D. simulans which are considered twin species due to their morphological similarity, do not mate even if they are kept together in a laboratory. Drosophila ananassae and D. pallidosa are twin species from Melanesia. In the wild they rarely produce hybrids, although in the laboratory it is possible to produce fertile offspring. Studies of their sexual behavior show that the males court the females of both species but the females show a marked preference for mating with males of their own species. A different regulator region has been found on Chromosome II of both species that affects the selection behavior of the females.
Pheromones play an important role in the sexual isolation of insect species. These compounds serve to identify individuals of the same species and of the same or different sex. Evaporated molecules of volatile pheromones can serve as a wide-reaching chemical signal. In other cases, pheromones may be detected only at a short distance or by contact.
In species of the melanogaster group of Drosophila, the pheromones of the females are mixtures of different compounds, there is a clear dimorphism in the type and/or quantity of compounds present for each sex. In addition, there are differences in the quantity and quality of constituent compounds between related species, it is assumed that the pheromones serve to distinguish between individuals of each species. An example of the role of pheromones in sexual isolation is found in 'corn borers' in the genus Ostrinia. There are two twin species in Europe that occasionally cross. The females of both species produce pheromones that contain a volatile compound which has two isomers, E and Z; 99% of the compound produced by the females of one species is in the E isomer form, while the females of the other produce 99% isomer Z. The production of the compound is controlled by just one locus and the interspecific hybrid produces an equal mix of the two isomers. The males, for their part, almost exclusively detect the isomer emitted by the females of their species, such that the hybridization although possible is scarce. The perception of the males is controlled by one gene, distinct from the one for the production of isomers, the heterozygous males show a moderate response to the odour of either type. In this case, just 2 'loci' produce the effect of ethological isolation between species that are genetically very similar.
Sexual isolation between two species can be asymmetrical. This can happen when the mating that produces descendants only allows one of the two species to function as the female progenitor and the other as the male, while the reciprocal cross does not occur. For instance, half of the wolves tested in the Great Lakes area of America show mitochondrial DNA sequences of coyotes, while mitochondrial DNA from wolves is never found in coyote populations. This probably reflects an asymmetry in inter-species mating due to the difference in size of the two species as male wolves take advantage of their greater size in order to mate with female coyotes, while female wolves and male coyotes do not mate.
Mechanical isolation[edit]
The flowers of many species of Angiosperm have evolved to attract and reward a single or a few pollinator species (insects, birds, mammals). Their wide diversity of form, colour, fragrance and presence of nectar is, in many cases, the result of coevolution with the pollinator species. This dependency on its pollinator species also acts as a reproductive isolation barrier.
Mating pairs may not be able to couple successfully if their genitals are not compatible. The relationship between the reproductive isolation of species and the form of their genital organs was signaled for the first time in 1844 by the French entomologist Léon Dufour. Insects' rigid carapaces act in a manner analogous to a lock and key, as they will only allow mating between individuals with complementary structures, that is, males and females of the same species (termed co-specifics).
Evolution has led to the development of genital organs with increasingly complex and divergent characteristics, which will cause mechanical isolation between species. Certain characteristics of the genital organs will often have converted them into mechanisms of isolation. However, numerous studies show that organs that are anatomically very different can be functionally compatible, indicating that other factors also determine the form of these complicated structures.
Mechanical isolation also occurs in plants and this is related to the adaptation and coevolution of each species in the attraction of a certain type of pollinator (where pollination is zoophilic) through a collection of morphophysiological characteristics of the flowers (called pollination syndrome), in such a way that the transport of pollen to other species does not occur.
Gametic isolation[edit]
The synchronous spawning of many species of coral in marine reefs means that inter-species hybridization can take place as the gametes of hundreds of individuals of tens of species are liberated into the same water at the same time. Approximately a third of all the possible crosses between species are compatible, in the sense that the gametes will fuse and lead to individual hybrids. This hybridization apparently plays a fundamental role in the evolution of coral species. However, the other two-thirds of possible crosses are incompatible. It has been observed that in sea urchins of the genus Strongylocentrotus the concentration of spermatocytes that allow 100% fertilization of the ovules of the same species is only able to fertilize 1.5% of the ovules of other species. This inability to produce hybrid offspring, despite the fact that the gametes are found at the same time and in the same place, is due to a phenomenon known as gamete incompatibility, which is often found between marine invertebrates, and whose physiological causes are not fully understood.
In some Drosophila crosses, the swelling of the female's vagina has been noted following insemination. This has the effect of consequently preventing the fertilization of the ovule by sperm of a different species.
In plants the pollen grains of a species can germinate in the stigma and grow in the style of other species. However, the growth of the pollen tubes may be detained at some point between the stigma and the ovules, in such a way that fertilization does not take place. This mechanism of reproductive isolation is common in the angiosperms and is called cross-incompatibility or incongruence. A relationship exists between self-incompatibility and the phenomenon of cross-incompatibility. In general crosses between individuals of a self-compatible species (SC) with individuals of a self-incompatible (SI) species give hybrid offspring. On the other hand, a reciprocal cross (SI x SC) will not produce offspring, because the pollen tubes will not reach the ovules. This is known as unilateral incompatibility, which also occurs when two SC or two SI species are crossed.
In coral reefs, gamete incompatibility prevents the formation of numerous inter-species hybrids.
Post-zygotic isolation[edit]
A number of mechanisms which act after fertilization preventing successful inter-population crossing are discussed below.
Zygote mortality and non-viability of hybrids[edit]
A type of incompatibility that is found as often in plants as in animals occurs when the egg or ovule is fertilized but the zygote does not develop, or it develops and the resulting individual has a reduced viability. This is the case for crosses between species of the frog order, where widely differing results are observed depending upon the species involved. In some crosses there is no segmentation of the zygote (or it may be that the hybrid is extremely non-viable and changes occur from the first mitosis). In others, normal segmentation occurs in the blastula but gastrulation fails. Finally, in other crosses, the initial stages are normal but errors occur in the final phases of embryo development. This indicates differentiation of the embryo development genes (or gene complexes) in these species and these differences determine the non-viability of the hybrids.
Similar results are observed in mosquitoes of the genus Culex, but the differences are seen between reciprocal crosses, from which it is concluded that the same effect occurs in the interaction between the genes of the cell nucleus (inherited from both parents) as occurs in the genes of the cytoplasmic organelles which are inherited solely from the female progenitor through the cytoplasm of the ovule.
In Angiosperms, the successful development of the embryo depends on the normal functioning of its endosperm.
The failure of endosperm development and its subsequent abortion has been observed in many interploidal crosses (that is, those between populations with a particular degree of intra or interspecific ploidy), and in certain crosses in species with the same level of ploidy. The collapse of the endosperm, and the subsequent abortion of the hybrid embryo is one of the most common post-fertilization reproductive isolation mechanism found in angiosperms.
Hybrid sterility[edit]
Mules are hybrids with interspecific sterility.
A hybrid may have normal viability but is typically deficient in terms of reproduction or is sterile. This is demonstrated by the mule and in many other well known hybrids. In all of these cases sterility is due to the interaction between the genes of the two species involved; to chromosomal imbalances due to the different number of chromosomes in the parent species; or to nucleus-cytoplasmic interactions such as in the case of Culex described above.
Hinnies and mules are hybrids resulting from a cross between a horse and a donkey or between a mare and a donkey, respectively. These animals are nearly always sterile due to the difference in the number of chromosomes between the two parent species. Both horses and donkeys belong to the genus Equus, but Equus caballus has 64 chromosomes, while Equus asinus only has 62. A cross will produce offspring (mule or hinny) with 63 chromosomes, that will not form pairs, which means that they do not divide in a balanced manner during meiosis. In the wild, the horses and donkeys ignore each other and do not cross. In order to obtain mules or hinnies it is necessary to train the progenitors to accept copulation between the species or create them through artificial insemination.
The sterility of many interspecific hybrids in angiosperms has been widely recognised and studied.
Interspecific sterility of hybrids in plants has multiple possible causes. These may be genetic, related to the genomes, or the interaction between nuclear and cytoplasmic factors, as will be discussed in the corresponding section. Nevertheless, in plants, hybridization is a stimulus for the creation of new species – the contrary to the situation in animals.
Although the hybrid may be sterile, it can continue to multiply in the wild by asexual reproduction, whether vegetative propagation or apomixis or the production of seeds.
Indeed, interspecific hybridization can be associated with polyploidia and, in this way, the origin of new species that are called allopolyploids. Rosa canina, for example, is the result of multiple hybridizations. The common wheat (Triticum aestivum) is an allohexaploid (allopolyploid with six chromosome sets) that contains the genomes of three different species.
Multiple mechanisms[edit]
In general, the barriers that separate species do not consist of just one mechanism. The twin species of Drosophila, D. pseudoobscura and D. persimilis, are isolated from each other by habitat (persimilis generally lives in colder regions at higher altitudes), by the timing of the mating season (persimilis is generally more active in the morning and pseudoobscura at night) and by behavior during mating (the females of both species prefer the males of their respective species). In this way, although the distribution of these species overlaps in wide areas of the west of the United States of America, these isolation mechanisms are sufficient to keep the species separated. Such that, only a few fertile females have been found amongst the other species among the thousands that have been analyzed. However, when hybrids are produced between both species, the gene flow between the two will continue to be impeded as the hybrid males are sterile. Also, and in contrast with the great vigor shown by the sterile males, the descendants of the backcrosses of the hybrid females with the parent species are weak and notoriously non-viable. This last mechanism restricts even more the genetic interchange between the two species of fly in the wild.
Hybrid sex: Haldane's rule[edit]
Haldane's rule states that when one of the two sexes is absent in interspecific hybrids between two specific species, then the sex that is not produced, is rare or is sterile is the heterozygous (or heterogametic) sex. In mammals, at least, there is growing evidence to suggest that this is due to high rates of mutation of the genes determining masculinity in the Y chromosome.
It has been suggested that Haldane's rule simply reflects the fact that the male sex is more sensitive than the female when the sex-determining genes are included in a hybrid genome. But there are also organisms in which the heterozygous sex is the female: birds and butterflies and the law is followed in these organisms. Therefore, it is not a problem related to sexual development, nor with the sex chromosomes. Haldane proposed that the stability of hybrid individual development requires the full gene complement of each parent species, so that the hybrid of the heterozygous sex is unbalanced (i.e. missing at least one chromosome from each of the parental species). For example, the hybrid male obtained by crossing D. melanogaster females with D. simulans males, which is non-viable, lacks the X chromosome of D. simulans.
Genetics[edit]
Pre-copulatory mechanisms in animals[edit]
The genetics of ethological isolation barriers will be discussed first. Pre-copulatory isolation occurs when the genes necessary for the sexual reproduction of one species differ from the equivalent genes of another species, such that if a male of species A and a female of species B are placed together they are unable to copulate. Study of the genetics involved in this reproductive barrier tries to identify the genes that govern distinct sexual behaviors in the two species. The males of Drosophila melanogaster and those of D. simulans conduct an elaborate courtship with their respective females, which are different for each species, but the differences between the species are more quantitative than qualitative. In fact the simulans males are able to hybridize with the melanogaster females. Although there are lines of the latter species that can easily cross there are others that are hardly able to. Using this difference, it is possible to assess the minimum number of genes involved in pre-copulatory isolation between the melanogaster and simulans species and their chromosomal location.
In experiments, flies of the D. melanogaster line, which hybridizes readily with simulans, were crossed with another line that it does not hybridize with, or rarely. The females of the segregated populations obtained by this cross were placed next to simulans males and the percentage of hybridization was recorded, which is a measure of the degree of reproductive isolation. It was concluded from this experiment that 3 of the 8 chromosomes of the haploid complement of D. melanogaster carry at least one gene that affects isolation, such that substituting one chromosome from a line of low isolation with another of high isolation reduces the hybridization frequency. In addition, interactions between chromosomes are detected so that certain combinations of the chromosomes have a multiplying effect.
Cross incompatibility or incongruence in plants is also determined by major genes that are not associated at the self-incompatibility S locus.
Post-copulation or fertilization mechanisms in animals[edit]
Reproductive isolation between species appears, in certain cases, a long time after fertilization and the formation of the zygote, as happens – for example – in the twin species Drosophila pavani and D. gaucha. The hybrids between both species are not sterile, in the sense that they produce viable gametes, ovules and spermatozoa. However, they cannot produce offspring as the sperm of the hybrid male do not survive in the semen receptors of the females, be they hybrids or from the parent lines. In the same way, the sperm of the males of the two parent species do not survive in the reproductive tract of the hybrid female. This type of post-copulatory isolation appears as the most efficient system for maintaining reproductive isolation in many species.
The development of a zygote into an adult is a complex and delicate process of interactions between genes and the environment that must be carried out precisely, and if there is any alteration in the usual process, caused by the absence of a necessary gene or the presence of a different one, it can arrest the normal development causing the non-viability of the hybrid or its sterility. It should be borne in mind that half of the chromosomes and genes of a hybrid are from one species and the other half come from the other. If the two species are genetically different, there is little possibility that the genes from both will act harmoniously in the hybrid. From this perspective, only a few genes would be required in order to bring about post copulatory isolation, as opposed to the situation described previously for pre-copulatory isolation.
In many species where pre-copulatory reproductive isolation does not exist, hybrids are produced but they are of only one sex. This is the case for the hybridization between females of Drosophila simulans and Drosophila melanogaster males: the hybridized females die early in their development so that only males are seen among the offspring. However, populations of D. simulans have been recorded with genes that permit the development of adult hybrid females, that is, the viability of the females is "rescued". It is assumed that the normal activity of these speciation genes is to "inhibit" the expression of the genes that allow the growth of the hybrid. There will also be regulator genes.
A number of these genes have been found in the melanogaster species group. The first to be discovered was "Lhr" (Lethal hybrid rescue) located in Chromosome II of D. simulans. This dominant allele allows the development of hybrid females from the cross between simulans females and melanogaster males. A different gene, also located on Chromosome II of D. simulans is "Shfr" that also allows the development of female hybrids, its activity being dependent on the temperature at which development occurs. Other similar genes have been located in distinct populations of species of this group. In short, only a few genes are needed for an effective post copulatory isolation barrier mediated through the non-viability of the hybrids.
As important as identifying an isolation gene is knowing its function. The Hmr gene, linked to the X chromosome and implicated in the viability of male hybrids between D. melanogaster and D. simulans, is a gene from the proto-oncogene family myb, that codes for a transcriptional regulator. Two variants of this gene function perfectly well in each separate species, but in the hybrid they do not function correctly, possibly due to the different genetic background of each species. Examination of the allele sequence of the two species shows that change of direction substitutions are more abundant than synonymous substitutions, suggesting that this gene has been subject to intense natural selection.
The Dobzhansky–Muller model proposes that reproductive incompatibilities between species are caused by the interaction of the genes of the respective species. It has been demonstrated recently that Lhr has functionally diverged in D. simulans and will interact with Hmr which, in turn, has functionally diverged in D. melanogaster to cause the lethality of the male hybrids. Lhr is located in a heterochromatic region of the genome and its sequence has diverged between these two species in a manner consistent with the mechanisms of positive selection. An important unanswered question is whether the genes detected correspond to old genes that initiated the speciation favoring hybrid non-viability, or are modern genes that have appeared post-speciation by mutation, that are not shared by the different populations and that suppress the effect of the primitive non-viability genes. The OdsH (abbreviation of Odysseus) gene causes partial sterility in the hybrid between Drosophila simulans and a related species, D. mauritiana, which is only encountered on Mauritius, and is of recent origin. This gene shows monophyly in both species and also has been subject to natural selection. It is thought that it is a gene that intervenes in the initial stages of speciation, while other genes that differentiate the two species show polyphyly. Odsh originated by duplication in the genome of Drosophila and has evolved at very high rates in D. mauritania, while its paralogue, unc-4, is nearly identical between the species of the group melanogaster. Seemingly, all these cases illustrate the manner in which speciation mechanisms originated in nature, therefore they are collectively known as "speciation genes", or possibly, gene sequences with a normal function within the populations of a species that diverge rapidly in response to positive selection thereby forming reproductive isolation barriers with other species. In general, all these genes have functions in the transcriptional regulation of other genes.
The Nup96 gene is another example of the evolution of the genes implicated in post-copulatory isolation. It regulates the production of one of the approximately 30 proteins required to form a nuclear pore. In each of the simulans groups of Drosophila the protein from this gene interacts with the protein from another, as yet undiscovered, gene on the X chromosome in order to form a functioning pore. However, in a hybrid the pore that is formed is defective and causes sterility. The differences in the sequences of Nup96 have been subject to adaptive selection, similar to the other examples of speciation genes described above.
Post-copulatory isolation can also arise between chromosomally differentiated populations due to chromosomal translocations and inversions. If, for example, a reciprocal translocation is fixed in a population, the hybrid produced between this population and one that does not carry the translocation will not have a complete meiosis. This will result in the production of unequal gametes containing unequal numbers of chromosomes with a reduced fertility. In certain cases, complete translocations exist that involve more than two chromosomes, so that the meiosis of the hybrids is irregular and their fertility is zero or nearly zero. Inversions can also give rise to abnormal gametes in heterozygous individuals but this effect has little importance compared to translocations. An example of chromosomal changes causing sterility in hybrids comes from the study of Drosophila nasuta and D. albomicans which are twin species from the Indo-Pacific region. There is no sexual isolation between them and the F1 hybrid is fertile. However, the F2 hybrids are relatively infertile and leave few descendants which have a skewed ratio of the sexes. The reason is that the X chromosome of albomicans is translocated and linked to an autosome which causes abnormal meiosis in hybrids. Robertsonian translocations are variations in the numbers of chromosomes that arise from either: the fusion of two acrocentric chromosomes into a single chromosome with two arms, causing a reduction in the haploid number, or conversely; or the fission of one chromosome into two acrocentric chromosomes, in this case increasing the haploid number. The hybrids of two populations with differing numbers of chromosomes can experience a certain loss of fertility, and therefore a poor adaptation, because of irregular meiosis.
In plants[edit]
Further information: Reproductive coevolution in Ficus
A large variety of mechanisms have been demonstrated to reinforce reproductive isolation between closely related plant species that either historically lived or currently live in sympatry. This phenomenon is driven by strong selection against hybrids, typically resulting from instances in which hybrids suffer reduced fitness. Such negative fitness consequences have been proposed to be the result of negative epistasis in hybrid genomes and can also result from the effects of hybrid sterility. In such cases, selection gives rise to population-specific isolating mechanisms to prevent either fertilization by interspecific gametes or the development of hybrid embryos.
Because many sexually reproducing species of plants are exposed to a variety of interspecific gametes, natural selection has given rise to a variety of mechanisms to prevent the production of hybrids. These mechanisms can act at different stages in the developmental process and are typically divided into two categories, pre-fertilization and post-fertilization, indicating at which point the barrier acts to prevent either zygote formation or development. In the case of angiosperms and other pollinated species, pre-fertilization mechanisms can be further subdivided into two more categories, pre-pollination and post-pollination, the difference between the two being whether or not a pollen tube is formed. (Typically when pollen encounters a receptive stigma, a series of changes occur which ultimately lead to the growth of a pollen tube down the style, allowing for the formation of the zygote.) Empirical investigation has demonstrated that these barriers act at many different developmental stages and species can have none, one, or many barriers to hybridization with interspecifics.
Examples of pre-fertilization mechanisms[edit]
A well-documented example of a pre-fertilization isolating mechanism comes from study of Louisiana iris species. These iris species were fertilized with interspecific and conspecific pollen loads and it was demonstrated by measure of hybrid progeny success that differences in pollen-tube growth between interspecific and conspecific pollen led to a lower fertilization rate by interspecific pollen. This demonstrates how a specific point in the reproductive process is manipulated by a particular isolating mechanism to prevent hybrids.
Another well-documented example of a pre-fertilization isolating mechanism in plants comes from study of the 2 wind-pollinated birch species. Study of these species led to the discovery that mixed conspecific and interspecific pollen loads still result in 98% conspecific fertilization rates, highlighting the effectiveness of such barriers. In this example, pollen tube incompatibility and slower generative mitosis have been implicated in the post-pollination isolation mechanism.
Examples of post-fertilization mechanisms[edit]
Crosses between diploid and tetraploid species of Paspalum provide evidence of a post-fertilization mechanism preventing hybrid formation when pollen from tetraploid species was used to fertilize a female of a diploid species. There were signs of fertilization and even endosperm formation but subsequently this endosperm collapsed. This demonstrates evidence of an early post-fertilization isolating mechanism, in which the hybrid early embryo is detected and selectively aborted. This process can also occur later during development in which developed, hybrid seeds are selectively aborted.
Effects of hybrid necrosis[edit]
Plant hybrids often suffer from an autoimmune syndrome known as hybrid necrosis. In the hybrids, specific gene products contributed by one of the parents may be inappropriately recognized as foreign and pathogenic, and thus trigger pervasive cell death throughout the plant. In at least one case, a pathogen receptor, encoded by the most variable gene family in plants, was identified as being responsible for hybrid necrosis.
Chromosomal rearrangements in yeast[edit]
In brewers' yeast Saccharomyces cerevisiae, chromosomal rearrangements are a major mechanism to reproductively isolate different strains. Hou et al. showed that reproductive isolation acts postzygotically and could be attributed to chromosomal rearrangements. These authors crossed 60 natural isolates sampled from diverse niches with the reference strain S288c and identified 16 cases of reproductive isolation with reduced offspring viabilities, and identified reciprocal chromosomal translocations in a large fraction of isolates.
Incompatibility caused by microorganisms[edit]
In addition to the genetic causes of reproductive isolation between species there is another factor that can cause post zygotic isolation: the presence of microorganisms in the cytoplasm of certain species. The presence of these organisms in a species and their absence in another causes the non-viability of the corresponding hybrid. For example, in the semi-species of the group D. paulistorum the hybrid females are fertile but the males are sterile, this is due to the presence of a Wolbachia in the cytoplasm which alters spermatogenesis leading to sterility. It is interesting that incompatibility or isolation can also arise at an intraspecific level. Populations of D. simulans have been studied that show hybrid sterility according to the direction of the cross. The factor determining sterility has been found to be the presence or absence of a microorganism Wolbachia and the populations tolerance or susceptibility to these organisms. This inter population incompatibility can be eliminated in the laboratory through the administration of a specific antibiotic to kill the microorganism. Similar situations are known in a number of insects, as around 15% of species show infections caused by this symbiont. It has been suggested that, in some cases, the speciation process has taken place because of the incompatibility caused by this bacteria. Two wasp species Nasonia giraulti and N. longicornis carry two different strains of Wolbachia. Crosses between an infected population and one free from infection produces a nearly total reproductive isolation between the semi-species. However, if both species are free from the bacteria or both are treated with antibiotics there is no reproductive barrier. Wolbachia also induces incompatibility due to the weakness of the hybrids in populations of spider mites (Tetranychus urticae), between Drosophila recens and D. subquinaria and between species of Diabrotica (beetle) and Gryllus (cricket).
Selection[edit]
Further information: Laboratory experiments of speciation
Selection for reproductive isolation between two Drosophila species.
Generation
Percentage of hybrids
1
49
2
17.6
3
3.3
4
1.0
5
1.4
10
0.6
In 1950 K. F. Koopman reported results from experiments designed to examine the hypothesis that selection can increase reproductive isolation between populations. He used D. pseudoobscura and D. persimilis in these experiments. When the flies of these species are kept at 16 °C approximately a third of the matings are interspecific. In the experiment equal numbers of males and females of both species were placed in containers suitable for their survival and reproduction. The progeny of each generation were examined in order to determine if there were any interspecific hybrids. These hybrids were then eliminated. An equal number of males and females of the resulting progeny were then chosen to act as progenitors of the next generation. As the hybrids were destroyed in each generation the flies that solely mated with members of their own species produced more surviving descendants than the flies that mated solely with individuals of the other species. In the adjacent table it can be seen that for each generation the number of hybrids continuously decreased up to the tenth generation when hardly any interspecific hybrids were produced. It is evident that selection against the hybrids was very effective in increasing reproductive isolation between these species. From the third generation, the proportions of the hybrids were less than 5%. This confirmed that selection acts to reinforce the reproductive isolation of two genetically divergent populations if the hybrids formed by these species are less well adapted than their parents.
These discoveries allowed certain assumptions to be made regarding the origin of reproductive isolation mechanisms in nature. Namely, if selection reinforces the degree of reproductive isolation that exists between two species due to the poor adaptive value of the hybrids, it is expected that the populations of two species located in the same area will show a greater reproductive isolation than populations that are geographically separated (see reinforcement). This mechanism for "reinforcing" hybridization barriers in sympatric populations is also known as the "Wallace effect", as it was first proposed by Alfred Russel Wallace at the end of the 19th century, and it has been experimentally demonstrated in both plants and animals.
The sexual isolation between Drosophila miranda and D. pseudoobscura, for example, is more or less pronounced according to the geographic origin of the flies being studied. Flies from regions where the distribution of the species is superimposed show a greater sexual isolation than exists between populations originating in distant regions.
Reproductive isolation can be caused by allopatric speciation. A population of Drosophila was divided into sub populations selected to adapt to different food types. After some generations the two sub populations were mixed again. Subsequent matings occurred between individuals belonging to the same adapted group.
On the other hand, interspecific hybridization barriers can also arise as a result of the adaptive divergence that accompanies allopatric speciation. This mechanism has been experimentally proved by an experiment carried out by Diane Dodd on D. pseudoobscura. A single population of flies was divided into two, with one of the populations fed with starch-based food and the other with maltose-based food. This meant that each sub population was adapted to each food type over a number of generations. After the populations had diverged over many generations, the groups were again mixed; it was observed that the flies would mate only with others from their adapted population. This indicates that the mechanisms of reproductive isolation can arise even though the interspecific hybrids are not selected against.
See also[edit]
Species problem
History of evolutionary thought
History of speciation
Notes[edit]
a. The DNA of the mitochondria and chloroplasts is inherited from the maternal line, i.e. all the progeny derived from a particular cross possess the same cytoplasm (and genetic factors located in it) as the female progenitor. This is because the zygote possesses the same cytoplasm as the ovule, although its nucleus comes equally from the father and the mother. | biology | 2393674 | https://sv.wikipedia.org/wiki/Variichthys%20jamoerensis | Variichthys jamoerensis | Variichthys jamoerensis är en fiskart som först beskrevs av Mees, 1971. Variichthys jamoerensis ingår i släktet Variichthys och familjen Terapontidae. IUCN kategoriserar arten globalt som sårbar. Inga underarter finns listade i Catalogue of Life.
Källor
Abborrartade fiskar
jamoerensis | swedish | 1.034018 |
sexual_repro_outside/biologyphp.txt | Skip to navigation Skip to main content Skip to footer
* [ About ](https://www.umt.edu/about/)
* [ Academics ](https://www.umt.edu/academics/)
* [ Admission and Aid ](https://www.umt.edu/admissions-and-financial-aid/)
* [ Student Life ](https://www.umt.edu/student-life/)
* [ Research ](https://www.umt.edu/um-research/)
* [ Athletics ](https://www.umt.edu/athletics/)
* [ My UM ](https://www.umt.edu/my/ "Current Student and Employee Quick Links")
* [ Alumni ](https://grizalum.org)
1. [ UM ](https://www.umt.edu/)
2. [ Grizzly Bear Recovery ](../default.php)
3. [ Grizzly Bears ](default.php)
4. Grizzly Bear Biology
# Grizzly Bear Recovery Program
## Site Navigation
__ Site Navigation
* [ Home ](../default.php)
* [ About Us ](../about/default.php)
* [ Grizzly Bears ](default.php)
* [ Publications ](../publications/default.php)
* [ Past Workshops ](../past-workshops/default.php)
* [ Support our Program ](../giving.php)
### Grizzly Bears Section Sidebar Navigation
* [ Grizzly Bear Ecosystems ](ecosystems.php)
* [ **Grizzly Bear Biology** ](biology.php)
* [ Grizzly Bear Identification ](identification.php)
# Grizzly Bear Biology
## Species Description
Grizzly bears ( _Ursus arctos horribilis_ ) belong to the Order Carnivora and
Family Ursidae. The grizzly bear is a member of the brown bear species ( _U.
arctos_ ) but the subspecies _U. a. horribilis_ is only found in North
America.
Grizzly bears are generally larger and more heavily built than other bear
species. Grizzly bears can be distinguished from black bears by longer, curved
claws, humped shoulders, and a face that appears concave. A wide range of
coloration from light brown to nearly black is common. In the lower 48 States,
male grizzly bears generally weigh between 400 and 600 lbs whereas females
usually weigh between 250 to 350 lbs. Grizzly bears typically live to be
around 25 years old.
Identifying Bears: Telling the difference between a grizzly bear and a black
bear can be tricky. Size and color alone are not sufficient to make a positive
identification. [ Learn how to tell the difference between black bears and
grizzlies ](identification.php) then test your knowledge at the Montana Fish,
Wildlife, and Parks [ Bear Identification Website
](http://fwp.mt.gov/education/hunter/bearID/ "FWP bear identification
website")
## Behavior
Grizzly bears are opportunistic omnivores that will eat fish, berries,
grasses, leaves, insects, roots, carrion, small mammals, fungi, nuts, and
ungulates.
Grizzly bears have home ranges (not territories) and they will share this
habitat with other grizzly bears although social systems influence movements
and interactions among resident bears. Home range sizes for adult female
grizzlies vary from 50 to 150 square miles whereas an adult male can have a
home range size of up to 600 square miles.
Grizzly bears in the lower 48 States spend 4 to 6 months in dens beginning in
October or November. During this period, they do not eat, drink, urinate, or
defecate. Over the course of the denning season, a bear may lose thirty
percent of its body weight. All of this weight is stored as fat which is
acquired during the 2 to 4 months prior to entering dens during a period
called hyperphagia. During hyperphagia, bears increase their food intake
dramatically and may gain as much as 3.64 lb/day.
Grizzly bears typically avoid humans. However, grizzly bears can fiercely
protect themselves, their young, and their food when they feel threatened. If
grizzly bears learn to seek human sources of food such as garbage, pet food,
bird seed, vegetables, or fruits; they may lose their tendency to avoid humans
and become aggressive instead.
## Reproductive Biology
Mating occurs from May through July, with a peak in mid-June. The age at which
females produce their first litter varies from 3 to 8 years old with litter
size varying from 1 to 4 cubs. Cubs are born inside the den in late January or
early February and remain with the female for 2 to 3 years. Grizzly bears have
one of the slowest reproductive rates among terrestrial mammals. Grizzly bear
females cease breeding successfully some time in their mid- to late 20s.
## References
Blanchard, B. M. and R. R. Knight. 1980. Status of grizzly bears in the
Yellowstone system. Transactions of the North American Wildlife and Natural
Resource Conference 45:263-267.
Blanchard, B. M., and R. R. Knight. 1991. Movements of Yellowstone grizzly
bears, 1975-87. Biological Conservation 58:41-67.
Craighead, J. J., J. S. Sumner, and J. A. Mitchell. 1995. The grizzly bears of
Yellowstone: Their ecology in the Yellowstone ecosystem, 1959-1992. Island
Press, Washington, D.C., USA.
Craighead, F. L., D. Paetkau, H. V. Reynolds, C. Strobeck, and E. R. Vyse.
1998. Use of microsatellite DNA analyses to infer breeding behavior and
demographic processes in an arctic grizzly bear population. Ursus 10:323-327.
Folk, G. E. Jr., A. Larson, and M. A. Folk. 1976. Physiology of hibernating
bears. Bears: Their Biology and Management pp.373-380. Proceedings of the 3rd
international conference on bear research and management, Binghamton, New
York, USA.
Harding, L. and J. A. Nagy. 1980. Responses of grizzly bears to hydrocarbon
exploration on Richards Island, Northwest Territories, Canada. Bears: Their
Biology and Management pp. 277-280. Proceedings of the 4th International
Conference on Bear Research and Management, Kalispell, Montana.
LeFranc, M. N. Jr., M. B. Moss, K. A. Patnode, and W. C. Sugg III, editors.
1987. Grizzly bear compendium. The National Wildlife Federation, Washington,
D.C., USA.
Linnell, J. D. C., J. E. Swenson, R. Andersen, and B. Barnes. 2000. How
vulnerable are denning bears to disturbance? Wildlife Society Bulletin
28:400-413.
Martinka, C. J. 1976. Ecological role and management of grizzly bears in
Glacier National Park, Montana. Bears: Their Biology and Management pp
147-156. 3rd international conference on bear research and management,
Binghamton, New York, USA.
Nelson, R. A. 1980. Protein and fat metabolism in hibernating bears.
Federation Proceedings 39:2955-2958.
Nowak, R.M. and J.L. Paradiso. 1983. Walker’s Mammals of the World, 4th
edition. The Johns Hopkins University Press, Baltimore, Maryland, USA.
Rausch, R. L. 1963. Geographic variation in size of North American brown
bears, _Ursus arctos_ L., as indicated by condylobasal length. Canadian
Journal of Zoology 41:33-45.
Rode, K. D. and C. T. Robbins. 2000. Why bears consume mixed diets during
fruit abundance. Canadian Journal of Zoology 78:1640-1645.
Schwartz, C. C., K. A. Keating, H. V. Reynolds, III, V. G. Barnes, Jr., R. A.
Sellers, J. E. Swenson, S. D. Miller, B. N. McLellan, J. Keay, R. McCann, M.
Gibeau, W. F. Wakkinen, R. D. Mace, W. Kasworm, R. Smith, and S. Herrero.
2003. Reproductive maturation and senescence in the female brown bear. Ursus
14:109-119.
Schwartz, C. C., S. D. Miller, and M. A. Haroldson. 2003\. Grizzly/brown
bear. Feldhamer, B. Thompson, and J. Chapman, eds. Wild mammals of North
America: Biology, Management, and Conservation pp. 556-586. Johns Hopkins
University Press, Baltimore, Maryland, USA.
Servheen, C. 1999. Status and management of the grizzly bear in the lower 48
United States. C. Servheen, S. Herrero, and B. Peyton, compilers. Bears:
Status survey and conservation action plan pp. 50-54. IUCN/SSC Bear and Polar
Bear Specialist Groups. IUCN, Gland, Switzerland.
Swenson, J. E., F. Sandegren, S. Brunberg, and P. Wabakken. 1997\. Winter den
abandonment by brown bears, _Ursus arctos_ : causes and consequences. Wildlife
Biology 3:35-38.
## Secondary Footer
* _Contact Us_ [ (406) 243-4903 ](tel:\(406\) 243-4903)
* [ [email protected] ](mailto:[email protected])
* Grizzly Bear Recovery Program
W.A. Franke College of Forestry and Conservation
U.S. Fish and Wildlife Service
University Hall, Room 309
[ Launch UM virtual tour. ](https://www.youvisit.com/#/vte/?data-
platform=v&data-link-type=immersive&data-inst=60290&data-loc=80241&data-
stopid=282020&data-image-width=100%&data-image-height=100%&)
[ 
](https://www.umt.edu)
* [ University Operator
406-243-0211 ](tel:4062430211)
* [ Contact Us ](https://www.umt.edu/contact/default.php)
* 32 Campus Drive
Missoula, MT 59812
* [ Accessibility ](https://www.umt.edu/accessibility)
* [ A to Z ](https://www.umt.edu/a-to-z)
* [ Directory ](https://www.umt.edu/directory/)
* [ Campus Map ](http://map.umt.edu)
* [ Campus Safety ](https://www.umt.edu/safety/)
* [ Employment ](https://umjobs.silkroad.com/)
* [ Refer A Griz ](https://apply.umt.edu/register/?id=324f3d51-df7a-490b-8806-ba22ea3e4227)
* [ __ ](https://www.facebook.com/umontana/)
* [ __ ](https://twitter.com/umontana/)
* [ __ ](https://www.youtube.com/user/UniversityOfMontana)
* [ __ ](https://www.instagram.com/umontana)
* [ __ ](https://www.linkedin.com/school/the-university-of-montana/)
© 2024 University of Montana. [ Privacy Policy
](https://www.umt.edu/about/privacy)
| biology | 4663265 | https://sv.wikipedia.org/wiki/Syzygium%20seemannianum | Syzygium seemannianum | Syzygium seemannianum är en myrtenväxtart som beskrevs av Elmer Drew Merrill och Lily May Perry. Syzygium seemannianum ingår i släktet Syzygium och familjen myrtenväxter. IUCN kategoriserar arten globalt som livskraftig.
Artens utbredningsområde är Fiji. Inga underarter finns listade i Catalogue of Life.
Källor
Myrtenväxter
seemannianum | swedish | 1.013488 |
sexual_repro_outside/brownbear.txt | Skip to Main Content
[  ](https://sandiegozoowildlifealliance.org/)
[ 
](https://library.sandiegozoo.org/)
1. [ International Environment Library Consortium ](http://www.ielc.info)
2. [ LibGuides ](https://ielc.libguides.com/)
3. [ San Diego Zoo Wildlife Alliance Library ](https://ielc.libguides.com/sdzg)
4. [ Brown Bear ( _Ursus arctos_ ) Fact Sheet ](https://ielc.libguides.com/sdzg/factsheets/brownbear)
5. Summary
Search this Guide Search
# Brown Bear ( _Ursus arctos_ ) Fact Sheet: Summary
* [ Summary ](https://ielc.libguides.com/sdzg/factsheets/brownbear/summary " Table of contents, how to cite, feedback")
* [ Taxonomy & History ](https://ielc.libguides.com/sdzg/factsheets/brownbear/taxonomy "Classification, nomenclature, taxonomic & evolutionary history, cultural history")
* [ Distribution & Habitat ](https://ielc.libguides.com/sdzg/factsheets/brownbear/distribution "Distribution, range, habitat")
* [ Physical Characteristics ](https://ielc.libguides.com/sdzg/factsheets/brownbear/characteristics "Physical measurements, appearance, sexual dimorphism, key characteristics")
* [ Behavior & Ecology ](https://ielc.libguides.com/sdzg/factsheets/brownbear/behavior "Activity, territorial behavior, social behavior, communication, locomotion, interspecies interactions")
* [ Diet & Feeding ](https://ielc.libguides.com/sdzg/factsheets/brownbear/diet "Diet, nutrition, feeding behavior")
* [ Reproduction & Development ](https://ielc.libguides.com/sdzg/factsheets/brownbear/reproduction "Courtship, reproduction, gestation & birth, life stages, longevity, mortality")
* [ Managed Care ](https://ielc.libguides.com/sdzg/factsheets/brownbear/managedcare "Longevity & reproduction in managed care, history in managed care")
* [ Population & Conservation Status ](https://ielc.libguides.com/sdzg/factsheets/brownbear/population "Population and conservation status, threats to survival, management actions")
* [ Bibliography & Resources ](https://ielc.libguides.com/sdzg/factsheets/brownbear/bibliography "References, additional internet resources")
## Brown Bear ( _Ursus arctos_ ) Fact Sheet
**Brown Bear ( _Ursus arctos_ ) **
Image credit: © San Diego Zoo Wildlife Alliance. All rights reserved.
Taxonomy | Physical Characteristics
---|---
**Describer (Date):** Linnaeus 1758
**Kingdom:** Animalia
**Phylum:** Chordata
**Class:** Mammalia
**Order:** Carnivora
**Family:** Ursidae
**Subfamily:** Caniforma
**Genus:** _Ursus_
**Species:** _Ursus arctos_
|
**Body Weight:**
Male 130-550 kg (287-1213 lb)
Female 80-250 kg (176-551 lb)
**Head/Body Length (Males & Females): **
1-2.8 m (3.3-9.2 ft)
**Shoulder Height:** up to 1.5 m (5 ft)
**Tail Length:** 60-200 mm (2-8 in)
**Pelage:** Pale tan, blond, gold, many shades of brown to black, gray or
silver; grizzly's guard hairs pale at tips.
Distribution & Status | Behavior & Ecology
**Range:** Europe, Middle East, Asia, northwestern U.S., western Canada
**Habitat:** Widest variety of habitats of any bear species; dry asian
steppes, temperate forests; sea level to 5,000 m (16,404 ft)
**IUCN Status:** Least Concern (2016 assessment)
**CITES Appendix:**
Appendix I: central Asia (Mongolia, China, Bhutan) and Mexico;
Appendix II: rest of world, except Alaskan populations
**Population in Wild:** More than 200,000
|
**Locomotion:** Normal gait - slow shuffle; walk 5.5-6 km/hr; gallop 56 km/hr
(35 mp/h)
**Activity Cycle:** Diurnal in North America (but active day and night when
food scarce); largely nocturnal in Europe; in cold climates undergo winter
dormancy.
**Social Groups:** Lasting bonds only between female and young.
**Diet:** Wide variety of plants and animals; diet more carnivorous than that
of American and Asiatic black bears.
**Predators:** Mainly humans; rare attacks in Siberia by tigers.
Reproduction & Development | Species Highlights
**Sexual:** Female - 3.5 yrs; first cubs 4-8 yrs; Male - about 5.5 yrs.
**Gestation:** 6-7 months
**Litter Size:** 2 - 3 common; up to 4
**Birth weight:** 400-500 g (14-18 oz)
**Age at Weaning:** 1.5-2.5 years
**Typical Life Expectancy:**
Wild populations: **** typical life expectancy not known
Managed care: median life expectancy of about 22 years in males and 27 years
in females
|
**Feature Facts**
* Rely on wide variety of seasonally available plant and animal food items: berries, pine seeds, grasses, roots, tubers, honey, ants, moths, small rodents, calves of moose, muskoxen, caribou, elk, and salmon.
* Most widespread bear in the world
* Shoulder hump, concave snout and smaller ears distinguish Brown Bear from Black Bear.
* Mother bears with young are extremely defensive and will attack male bears.
* Have lowest reproduction rate of any mammal, females start breeding at 5-6 years of age with 3-4 years between litters.
* In a new enrichment strategy as of 2010, exhibit spaces have been connected for two young grizzly bears and an elderly Manchurian brown bear at the San Diego Zoo. The bears can now take turns using the whole area; this intelligent and highly curious species benefits greatly from added activities and a chance to smell tracks left by other bears.
## About This Fact Sheet
© 2010-2019 San Diego Zoo Wildlife Alliance. Updated 2015. Minor updates 2019.
**How to cite:** Brown Bear ( _Ursus arctos_ ) Fact Sheet. c2010-2019. San
Diego (CA): San Diego Zoo Wildlife Alliance; [accessed YYYY Mmm dd].
http://ielc.libguides.com/sdzg/factsheets/ brownbear.
(Note: replace YYYY Mmm dd with date accessed, e.g., 2015 Jan 15)
**Disclaimer:** Although San Diego Zoo Wildlife Alliance makes every attempt
to provide accurate information, some of the facts provided may become
outdated or replaced by new research findings. Questions and comments may be
addressed to [ [email protected] ](mailto:[email protected]) .
## SDZWA Library Links
* [ Animal Fact Sheet Index ](http://ielc.libguides.com/sdzg/factsheets/index)
A-to-Z listing of all SDZWA Animal Fact Sheets, by common and scientific name.
Browse by taxonomic group (Mammals, Birds, Amphibians & Reptiles,
Invertebrates), or by SDZWA park habitat or Conservation Hub.
In each fact sheet, find detailed information by clicking on the tabs at the
top of the page. A list of sources is shared in the Bibliography.
* [ Library Home ](http://library.sandiegozoo.org/)
Home page, San Diego Zoo Wildlife Alliance Library
* [ Contact Us ](https://library.sandiegozoo.org/contact-us/)
Email the SDZWA Library at [email protected].
* * [ **Next:** Taxonomy & History >> ](https://ielc.libguides.com/sdzg/factsheets/brownbear/taxonomy)
* Last Updated: Mar 6, 2024 7:03 PM
* URL: https://ielc.libguides.com/sdzg/factsheets/brownbear
* [ __ Print Page ](javascript: window.print\(\);)
[ Login to LibApps
](https://ielc.libapps.com/libapps/login.php?site_id=6975&target64=L2xpYmd1aWRlcy9hZG1pbl9jLnBocD9nPTY5MjkwNyZwPTQ5MDk4NDI=)
Tags: [ alaska ](https://ielc.libguides.com/srch.php?tag=alaska&default_lg=1)
, [ bear ](https://ielc.libguides.com/srch.php?tag=bear&default_lg=1) , [
brown bear ](https://ielc.libguides.com/srch.php?tag=brown+bear&default_lg=1)
, [ carnivore
](https://ielc.libguides.com/srch.php?tag=carnivore&default_lg=1) , [ cub
](https://ielc.libguides.com/srch.php?tag=cub&default_lg=1) , [ fact sheet
](https://ielc.libguides.com/srch.php?tag=fact+sheet&default_lg=1) , [ fur
](https://ielc.libguides.com/srch.php?tag=fur&default_lg=1) , [ grizzly
](https://ielc.libguides.com/srch.php?tag=grizzly&default_lg=1) , [
hibernation
](https://ielc.libguides.com/srch.php?tag=hibernation&default_lg=1) , [ north
america ](https://ielc.libguides.com/srch.php?tag=north+america&default_lg=1)
, [ san diego zoo
](https://ielc.libguides.com/srch.php?tag=san+diego+zoo&default_lg=1) , [
sdzwa ](https://ielc.libguides.com/srch.php?tag=sdzwa&default_lg=1)
[ __ __ ](javascript:void\(0\); "Back to Top")
* * *
**SDZWA Library Mission:** To provide outstanding information resources and
services to advance knowledge in animal and plant care and conservation,
inspire passion for nature, ignite personal responsibility, and strengthen our
organization’s capacity to save species worldwide.
© 2024 San Diego Zoo Wildlife Alliance. All rights reserved.
[ 
](https://sandiegozoowildlifealliance.org/)
| biology | 4880774 | https://sv.wikipedia.org/wiki/Lista%20%C3%B6ver%20NGC-objekt%20%281%E2%80%931000%29 | Lista över NGC-objekt (1–1000) | Detta är en partiell lista över objekten 1–1000 i New General Catalogue (NGC). Katalogen består huvudsakligen av stjärnhopar, nebulosor och galaxer. Övriga objekt i katalogen går att hitta på de andra undersidorna till New General Catalogue.
Informationen om stjärnbilderna i listan kommer ur The Complete New General Catalogue and Index Catalogue of Nebulae and Star Clusters by J. L. E. Dreyer, som nåddes genom VizieR Service (webbsida: http://vizier.u-strasbg.fr/viz-bin/VizieR). Galaxernas morfologiska typer och objekt som tillhör Lilla magellanska molnet är identifierade genom att använda NASA/IPAC Extragalactic Database (webbsida: http://nedwww.ipac.caltech.edu/). Övrigt data i tabellen kommer från SIMBAD Astronomical Database (webbsida: http://simbad.u-strasbg.fr/simbad/) om inget annat nämns.
1–100
101–200
201–300
301–400
401–500
501–600
601–700
701–800
801–900
901–1000
Referenser
Noter
1
NGC-objekt 0001-0999 | swedish | 0.887774 |
sexual_repro_outside/grizzlybearursusarct.txt | Skip to main content
[  ](/ "FWS Home")
[ U.S. Fish & Wildlife Service ](/ "FWS Home")
Toggle navigation
## Utility (Top) navigation
* [ About Us ](/about) __ Forward
__ Back
* [ About Us ](/about)
* [ Mission & Vision ](/about/mission-and-vision)
* [ Leadership ](/about/leadership)
* [ Our Organization ](/about/programs)
* [ Our Facilities ](/our-facilities)
* [ Regions ](/about/regions)
* [ Laws & Regulations ](/laws) __ Forward
__ Back
* [ Laws & Regulations ](/laws)
* [ Laws, Agreements & Treaties ](/library/categories/laws)
* [ Hunting Regulations ](/refuges/hunting/rules-regulations-and-improved-access)
* [ Library ](/library/collections) __ Forward
__ Back
* [ Library ](/library)
* [ Categories ](/library/categories)
* [ Collections ](/library/collections)
*
* [ Home ](/)
* [ Services ](/services "Access services provided by FWS") __ Forward
__ Back
* [ Services ](/services "Access the landing page for services provided by FWS")
* [ Duck Stamps ](/service/duck-stamps) __ Forward
__ Back
* [ Duck Stamps ](/service/duck-stamps)
* [ Buy a Duck Stamp or E-Stamp ](/service/buy-duck-stamp-or-e-stamp)
* [ Buy a Junior Duck Stamp ](/service/buy-junior-duck-stamp)
* [ Fish Stocking ](/service/fish-stocking)
* [ Importing & Exporting ](/service/importing-and-exporting)
* [ Consultation & Technical Assistance ](/service/consultation-and-technical-assistance) __ Forward
__ Back
* [ Consultation & Technical Assistance ](/service/consultation-and-technical-assistance)
* [ ESA Section 7 Consultation ](/service/section-7-consultations)
* [ Habitat Conservation Planning (HCPs) ](/service/habitat-conservation-plans)
* [ Candidate Conservation Agreements (CCA & CCAA) ](/service/candidate-conservation-agreements-assurances)
* [ Safe Harbour Agreements (SHA) ](/service/safe-harbor-agreements)
* [ Conservation Banking ](/service/conservation-banking)
* [ Coastal Barrier Resources Act Project Consultation ](/service/coastal-barrier-resources-act-project-consultation)
* [ Coastal Barrier Resources System Property Documentation ](/service/coastal-barrier-resources-system-property-documentation)
* [ Financial Assistance ](/service/financial-assistance)
* [ Species Management ](/service/species-management)
* [ Investigational New Animal Drugs (INADS) ](/service/investigational-new-animal-drugs-inads)
* [ Permits ](/service/permits)
* [ Search All Services ](/service/search)
[ 
](/carp/service/duck-stamps) [ Duck Stamps ](/carp/service/duck-stamps) [ One
of the easiest ways that anyone can support bird habitat conservation is by
buying duck stamps. ](/carp/service/duck-stamps)
* [ Species ](/species) __ Forward
__ Back
* [ Species ](/species)
* [ Explore Taxonomic Tree ](/explore-taxonomic-tree)
* [ Find a Species ](/species/search)
[ 
](/story/coolest-mammals-earth) [ Interest story ](/story/coolest-mammals-
earth) [ Bats: “The Coolest Mammals on Earth” ](/story/coolest-mammals-earth)
* [ Visit Us ](/visit-us) __ Forward
__ Back
* [ Visit Us ](/visit-us)
* [ Events ](/events)
* [ Recreation Passes ](/service/federal-recreational-lands-passes)
* [ Outdoor Recreation ](/activities)
* [ Where to Hunt ](/hunting/map)
* [ Where to Fish ](/fishing/map)
* [ Our Locations ](/our-facilities)
[ 
](/activity/auto-tour) [ Scenic Drives ](/activity/auto-tour) [ Tour routes
of great scenic drives on National Wildlife Refuges. ](/activity/auto-tour)
* [ Get Involved ](/get-involved) __ Forward
__ Back
* [ Get Involved ](/get-involved)
* [ Careers and Internships ](/careers)
* [ Volunteering ](/volunteer-opportunity)
* [ Friends Partnerships ](/program/friends-partnerships)
* [ Learning Opportunities ](/training)
* [ Education Programs ](/education-programs)
* [ Events ](/events)
* [ Partnerships ](/partner) __ Forward
__ Back
* [ Partnerships ](/partner)
* [ Partnership Categories ](/partner/categories)
* [ Partner List ](/partner/search)
[ 
](/volunteer-opportunity) [ Volunteer ](/volunteer-opportunity) [ Search for
volunteer opportunities around the country ](/volunteer-opportunity)
* [ Newsroom ](/news) __ Forward
__ Back
* [ Newsroom ](/news)
* [ Press Releases ](/press-release)
* [ Congressional Testimony ](/testimony)
* [ Media Contacts ](/media-contacts)
[ 
](/news/wildlife-wonders) [ Wild Things ](/news/wildlife-wonders) [ News
about wonderful wild things and places ](/news/wildlife-wonders)
* [ Initiatives ](/initiatives) __ Forward
__ Back
* [ Initiatives ](/initiatives)
* [ Combating Wildlife Trafficking ](/initiative/combating-wildlife-trafficking)
* [ Director's Priorities ](/initiative/directors-priorities)
* [ Climate Change ](/initiative/climate-change)
* [ Hunting ](/initiative/hunting)
* [ Fishing ](/initiative/fishing)
* [ Invasive Species ](/initiative/invasive-species)
* [ Pollinators ](/initiative/pollinators)
* [ Protecting Wildlife ](/initiative/protecting-wildlife)
[ 
](/initiative/climate-change) [ Climate Action ](/initiative/climate-change)
[ FWS is taking steps to mitigate climate impacts ](/initiative/climate-
change)
* [ I want to ](/) __ Forward
__ Back
* I Want To
* [ Report Wildlife Crime ](/wildlife-crime-tips "Report wildlife trafficking or other wildlife crime to our tip line")
* [ Do Business with FWS ](/program/contracting "info on contracting with FWS")
* [ Volunteer ](/volunteer-opportunity)
* [ Find a Job or Internship ](/careers)
* [ Visit a Refuge ](/visit-us/refuges)
* [ Buy a Duck Stamp ](/service/buy-duck-stamp-or-e-stamp)
* [ Apply for a Permit ](/service/permits "Apply for a Permit or License")
* [ Find Funding ](/service/financial-assistance)
* [ Find Training ](/training)
[ 
](/jobs) [ Wild work ](/jobs) [ Search employment opportunities with USFWS
](/jobs)
## Search
Search
Search
Enter the terms you wish to search for.
×
# Grizzly Bear
[ Image Details ](/banner/natdiglib1060fulljpg)
[ View Profile ](/species/grizzly-bear-ursus-arctos-horribilis)
FWS Focus
overview characteristics geography timeline information & media contact
## Overview
Characteristics
Overview
Grizzly bears, _Ursus arctos horribilis_ , are a member of the brown bear
species, _U. arctos_ , that occurs in North America, Europe and Asia. The
subspecies _U. a. horribilis_ is limited to North America and historically
existed throughout much of the western half of the contiguous United States,
central Mexico, western Canada and most of Alaska. Prior to 1800, an estimated
50,000 grizzly bears were distributed in one large contiguous area throughout
all or portions of 18 western States, including Washington, Oregon,
California, Idaho, Montana, Wyoming, Nevada, Colorado, Utah, New Mexico,
Arizona, North Dakota, South Dakota, Minnesota, Nebraska, Kansas, Oklahoma and
Texas. Grizzly bears were probably most common in the Rocky Mountains, along
the Upper Missouri River and in California. Grizzly bears were less common or
did not occur in large expanses of the North American deserts and Great Plains
ecoregions.
With the arrival of Europeans to North America, grizzly bears were seen as a
threat to livestock and human safety and, therefore, an impediment to westward
expansion and settlement. In the 1800s, in concert with European settlement of
the American West and government-funded bounty programs which aimed at
eradication, grizzly bears were shot, poisoned and trapped wherever they were
found. The resulting declines in range and population were dramatic with rapid
extinction of populations from most of Mexico and from the central and
southwestern United States and California. Grizzly bears were reduced to close
to 2% of their former range in the 48 contiguous states by the 1930s, with a
corresponding decrease in population, approximately 125 years after first
contact with European settlers. In the early 20th century, new regulations
were designed to stop future extirpations. In some areas, the protections came
too late. By 1975, grizzly bear populations in the 48 contiguous states had
been reduced to between 700 to 800. Although significant numbers remained in
Alaska and northern Canada, individuals were restricted largely to the
confines of national parks and wilderness areas in Washington, Idaho, Montana
and Wyoming. Grizzly bears were relegated to these areas in the 48 contiguous
states primarily because of limited human influences.
The 1993 U.S. Fish and Wildlife Service Recovery Plan identified six
ecosystems, with recovery zones at the core of each, to further recovery
efforts. Each recovery zone represents an area large enough and of sufficient
habitat quality to support a recovered grizzly bear population. The plan
recognized that grizzly bears will move and reside permanently in areas
outside the recovery zones and that connectivity between recovery areas would
be necessary for isolated populations to increase and sustain themselves at
recovery levels.
The recovery zones identified are:
* The Greater Yellowstone, referred to as GYE, in northwestern Wyoming, eastern Idaho and southwestern Montana
* The Northern Continental Divide, referred to as NCDE, of north-central Montana
* The North Cascades area of north-central Washington
* The Selkirks, referred to as SE, area of northern Idaho, northeast Washington and southeast British Columbia
* The Cabinet-Yaak, referred to as CYE, area of northwestern Montana and northern Idaho
* The Bitterroot, referred to as BE, in the Bitterroot Mountains of central Idaho and western Montana
Currently, there are at least 1,923 individuals in the 48 contiguous states,
with 727 in the GYE demographic monitoring area, 1,092 in the NCDE, about 60
in the CYE and a minimum of 44 in the United States portion of the SE,
although some bears have home ranges that cross the international border, as
documented by C.M. Costello and L. Roberts in 2021 and M.A. Haroldson and
others also in 2021. In the GYE, this estimate does not capture the entire
distribution of grizzly bears. In addition, grizzly bears have been verified
in areas between ecosystems; however, there are likely few resident grizzly
bears in the 48 contiguous states outside of the GYE, NCDE, CYE and SE. There
are currently no known populations within the North Cascades or the Bitterroot
Mountains of central Idaho and western Montana.
Estimated distribution, or current range, represents areas in which grizzly
bears are known to have established home ranges and continuously reside.
Ecosystems are generally considered to be the larger area surrounding the
recovery zones in which grizzly bears may be anticipated to occur as part of
the same population. The Species List Area captures current range and
additional areas of low-density peripheral occurrences and transitory
individuals. Grizzly bears are expanding on the landscape, can disperse large
distances and are not easily detectable. Developed through a standardized
protocol, the Species List Area includes additional areas of verified outlier
locations gathered by our state, federal and Tribal partner agencies, such as
verified sightings, mortalities, conflicts and radio-collared individuals
outside of current range.
* [ Map of current estimated occupied range for grizzly bears in the lower-48 States ](/media/grizzly-bear-recovery-zones-and-estimated-distributions-0)
* [ Map of Species List Area for grizzly bear map used for consultation ](/media/grizzly-bear-species-list-area-map-0)
Grizzly bears in the 48 contiguous states are currently protected as a
threatened species. It is illegal to harm, harass or kill these bears, except
in cases of self-defense or the defense of others. Grizzly bear conservation
is complex and only made possible through a variety of partnerships with the
Interagency Grizzly Bear Committee, state wildlife agencies, Native American
Tribes, federal agencies, universities and other organizations.
### Bear Safety
Learn the characteristics of bears and what you can do to prevent human-bear
conflict. Check out our [ Bear Safety ](/node/382566) page. For more
information on living and recreating in grizzly bear country, visit the [
Interagency Grizzly Bear Committee's bear safety page
](http://igbconline.org/bear-safety/) .
Who do you call if you experience a conflict with grizzly bears? [ Click here
to view grizzly bear conflict contacts ](/media/grizzly-bear-conflict-
contacts-0) .
[ New grizzly bear hazing guidelines for landowners and livestock producers.
](/media/grizzly-bear-hazing-guidelines-guidance-livestock-owners-homeowners-
and-general-public)
### Annual Reports
* [ 2022 Grizzly Bear Recovery Program Annual Report ](/media/2022-gbrp-annual-report)
* [ 2021 Grizzly Bear Recovery Program Annual Report ](/media/2021-grizzly-bear-recovery-program-annual-report)
* [ Cabinet-Yaak Grizzly Bear Recovery Area 2022 Research and Monitoring Progress Report ](/media/cabinet-yaak-grizzly-bear-recovery-area-2022-research-and-monitoring-progress-report)
* [ Selkirk Mountains Grizzly Bear Recovery Area 2022 Research and Monitoring Progress Report ](/media/selkirk-mountains-grizzly-bear-recovery-area-2022-research-and-monitoring-progress-report)
### Scientific Name
Ursus arctos horribilis
Common Name
brown bear
grizzly bear
FWS Category
Mammals
Kingdom
[ Animalia ](/species/animals-animalia)
### Location in Taxonomic Tree [ __ ]()
Species
[ Ursus arctos ](/taxonomic-tree/32094 )
Subspecies
[ Ursus arctos horribilis ](/taxonomic-tree/34975 )
### Identification Numbers
TSN: [ __ ]( "Taxonomic Serial Number")
[ 202385
](https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=202385)
## Characteristics
Characteristic category
### Physical Characteristics
Characteristics
Color & Pattern
Their coloration varies from light brown to nearly black. The coat features
longer guard hairs over a dense underfur with tips that are usually silver or
golden in color – hence the name _grizzly_ .
Size & Shape
They can be distinguished from black bears by longer, less curved front claws,
humped shoulders and a more concave facial profile.
Weight
Grizzly bears are generally larger and heavier than other bears. Adult males
average 400 to 600 pounds (200 to 300 kilograms) and adult females 250 to 350
pounds (110 to 160 kilograms) in the 48 contiguous states.
Characteristic category
### Life Cycle
Characteristics
Life Span
Grizzly bears are long-lived mammals, generally living to be around 25 years
old, although some wild bears have lived for over 35 years.
Life Cycle
Grizzly bears have three life stages: dependent young, subadults and adults.
Dependent young are usually less than 2 years old and depend on and are
associated with their mother, relying on her for food, protection, and
survival. There are two primary sub-categories of dependent young: cubs,
defined as cubs born during the most recent denning season and less than one
year old, and yearlings.
Grizzly bears have a promiscuous mating system. Mating occurs from May through
July, with a peak in mid-June. Although females mate in spring and early
summer, their fertilized embryos do not implant into the uterus for further
development until late fall. Fat stores obtained by female grizzly bears at
the end of fall are positively correlated with earlier birth dates and faster
growth rates of their cubs. Additionally, a body fat threshold may exist below
which females may not produce cubs, even when bred. Cubs are born in the den
in late January or early February and nurse for 3 to 4 months inside the den
and after den emergence, but also increasingly eat foods with their mother
once outside the den. Yearlings den with their mother but do not nurse in the
den. Outside of the den, yearlings eat the same foods as their mother, but
also occasionally nurse.
Shortly after den emergence, 2-year-old offspring generally leave their mother
to become subadults. Subadults are typically not sexually mature enough to
breed; however, a small percentage of 3-year-old females do breed and produce
cubs as 4-year-olds. Some subadults, generally males, may disperse away from
their mother and establish their own home range.
Adult bears are more than 4-years-old and have reached sexual maturity. Some
bears may not breed until they are older than 5-years-old, but they have the
ability to reproduce once they reach the adult stage. Adults generally live
into their mid- to late-20s, although some wild bears have lived over 35
years. Female reproductive senescence starts around age 25 for those long-
lived individuals.
Age of first reproduction, which averages 5.8 to 6.3 years, litter size, which
averages 2.1 to 2.19 cubs per litter, and inter-birth interval, which is the
average number of years between litters, averages 2.78 to 3.4 years, may be
related to nutritional state and, or, density dependent effects and varies
between ecosystems. Grizzly bears have one of the slowest reproductive rates
among terrestrial mammals, resulting primarily from these reproductive
factors: late age of first reproduction, small average litter size and the
long inter-birth interval. Given these factors, it may take a female grizzly
bear 10 or more years to replace herself in a population. The slow
reproductive rate should also be understood in the context of having one of
the longer life spans of terrestrial mammals. To that end, _Ursus arctos_ in
90th percentile for longevity. With a population being made up of numerous
overlapping generations, it is possible for mothers, daughters and
granddaughters to be reproductively active at the same time. Grizzly bear
females typically cease reproducing some time in their mid-to-late 20s.
Characteristic category
### Habitat
Characteristics
Habitat
Grizzly bears use a variety of habitats. In general, a grizzly bear’s
individual habitat needs and daily movements are largely driven by the search
for food, water, mates, cover, security or den sites. The available habitat
for bears is also influenced by people and their activities. Human activities
are the primary factor impacting habitat security and the ability of bears to
find and access foods, mates, cover and den sites. Other factors influencing
habitat use and function for grizzly bears include overall habitat
productivity, which is defined by food distribution, quality and abundance.
Overall habitat productivity is also defined by the availability of habitat
components, like denning areas and cover types. Additionally, grizzly bear
social dynamics, learned behavior and preferences of individual grizzly bears,
as well as grizzly bear population density and random variation are important
aspects. Water is an important habitat requirement as well; however, we have
no information to suggest that water is limiting in the habitat that bears
currently occupy, but may have limited distribution in portions of historical
range.
Grizzly bears use a variety of cover types to rest and shelter. Grizzly bears
often select bed sites with horizontal and vertical cover, especially at day
bed sites suggesting that bed site selection is important for concealment from
humans. The interspersion of open areas as feeding sites associated with cover
are important, probably because diverse habitat complexes, such as forest
interspersed with moist grass-forb meadows, provide both abundant food and
cover. Generally, areas with vegetative cover are important to grizzly bears
for use as bedding sites. Beds underneath any type of vegetative cover, not
necessarily always forest cover, provide bears shade during the hottest parts
of the day and a place to sleep at night.
The six ecosystems occur in mountainous ecoregions and each ecosystem provide
the habitat heterogeneity necessary for adequate food, denning and cover
resources. Because there are limited opportunities to increase or control
these habitat components, the objective for grizzly bear habitat management
has been, and continues to be, to reduce or mitigate the risk of human-caused
mortality and displacement. An effective habitat management tool for reducing
grizzly bear mortality risk on public lands is managing motorized access to
ensure bears have secure areas away from humans.
### Unmanaged motorized access:
* Increases human interaction and potential grizzly bear mortality risk
* Increases displacement from important habitat
* Increases habituation to humans
* Decreases habitat where energetic, meaning food, requirements can be met
Managing motorized access on public lands helps ameliorate these impacts.
Other habitat management tools that minimize displacement and reduce grizzly
bear mortality risk include regulating livestock allotments and developed
sites on public lands. Implementing food storage orders on public lands also
reduces mortality risk for both humans and grizzly bears. Requiring users and
recreationists in grizzly bear habitat to store their food, garbage and other
bear attractants in bear-proof, inaccessible ways reduces encounters and
human-grizzly bear conflicts. In addition, encouraging users and
recreationists to carry bear spray, and know how to use it, helps reduce the
potential for injury to people and bears.
Characteristic category
### Food
Characteristics
Food
The 48 contiguous states provide highly diverse landscapes which contain a
wide array of habitat types and bear foods across and within the ecosystems.
Plant communities vary from grasslands at lower elevations, which are defined
as less than 6,230 feet (1,900 meters) to shrub fields that are created by
fires, avalanches or timber harvest, to conifer forests at mid-elevations and
subalpine and alpine meadows at higher elevations, defined as greater than
7,870 feet (2,400 meters). Grizzly bears are opportunistic omnivores and
display great diet plasticity - even within a population. As such, individuals
shift their diet according to foods that are most nutritious, for example,
available foods that are high in fat, protein, and, or, carbohydrates. An
extensive literature review documented more than 260 species of foods that
grizzly bears consume in the Greater Yellowstone Ecosystem, which represents
four of the five kingdoms of life. The ability to use whatever food resources
are available is likely one reason brown bears are the most widely distributed
bear species in the world, occupying habitats from deserts to alpine mountains
and everything in between. This ability to live in a variety of habitats and
eat a wide array of foods makes grizzly bears a generalist species. In
contrast, specialist species like mountain lions, eat only a few specific
foods or live in only one or two specific habitat types. Morphological
adaptations that support a diverse diet include crushing molars and the
greatest intestinal length relative to body length of any carnivore.
Grizzly bear diets are highly variable among individuals, seasons and years,
and between ecosystems. They opportunistically seek and consume whatever plant
and animal foods are available to them. Grizzly bears will consume almost any
food available including living or dead mammals or fish, insects, worms,
plants, human-related foods and garbage. In areas where animal matter is less
available, berries, grasses, roots, bulbs, tubers, seeds and fungi are
important in meeting protein and caloric requirements. Grizzly bears often
sample new foods so that they have alternative options in years when preferred
foods are scarce. In the Greater Yellowstone Ecosystem, it has been noted
that, after 10 years of food habits data collection, new feeding strategies
continued to appear annually in this population.
In addition, grizzly bears opportunistically prey on livestock, agricultural
crops, like grain, corn, garbanzo beans and melons, as well as other human
foods. Cattle and sheep depredation rates are generally higher where bear
densities are higher, and in later summer months. In the Greater Yellowstone
and Northern Continental Divide ecosystems, depredation is generally higher
where livestock is more abundant, such as areas with livestock allotments and
privately owned ranchland. Livestock grazing is less common in the Cabinet-
Yaak and Selkirks ecosystems, and depredation rates are correspondingly lower.
Grizzly bears also opportunistically prey on small livestock, such as
chickens, llamas, and goats, which primarily occur on private land.
Food resources are especially important during the period leading up to
hibernation when grizzly bears must consume energetically rich foods to build
up fat reserves to survive denning and post-denning periods. Fat stores
provide a source of energy and insulate the bear from cold temperatures during
hibernation. Also, fat stores obtained by female grizzly bears at the end of
fall are positively correlated with earlier birth dates and quicker growth
rates of their cubs. Additionally, a body fat threshold may exist below which
females may not produce cubs, even when bred; studies have shown that females
with less than 20% body fat are unlikely to produce cubs. However, we are
unaware of a minimum body fat threshold for survival during the denning
period.
Characteristic category
### Behavior
Characteristics
Behavior
Grizzly bears hibernate in winter; hibernation is a life history strategy
bears use to cope with seasons of low food abundance. In preparation for
hibernation, bears increase their food intake dramatically during a period
called hyperphagia. Hyperphagia occurs throughout the two to four months prior
to den entry, which runs August through November. During hyperphagia, excess
food is converted into fat, and grizzly bears may gain as much as 3.64 pounds
a day (1.65 kilograms a day). Grizzly bears must consume foods rich in protein
and carbohydrates in order to build up fat reserves to survive denning and
post-denning periods. Fat stores are crucial to the hibernating bear as they
provide a source of energy and insulate the bear from cold temperatures, and
are equally important in providing energy to the bear upon emergence from the
den when food is still sparse relative to metabolic requirements. However, we
are unaware of a minimum body fat threshold for survival during the denning
period and documentation of natural mortality in independent-age bears is low
for non-collared individuals.
Grizzly bears in the 48 contiguous states hibernate in dens for four to six
months each year, typically entering dens between October and December, with
males entering their dens later than females. Females give birth to cubs in
the den in late January to early February. On average, males exit dens from
early March to late April. Females typically emerge from their dens from mid-
March to mid-May, with females with cubs emerging later from mid-April to
late-May.
Grizzly bears typically hibernate alone in dens, except for females with young
and subadult siblings who occasionally hibernate together. Grizzly bears
usually dig dens on steep slopes where wind and topography cause an
accumulation of deep snow and where the snow is unlikely to melt during warm
periods. Most dens are located at higher elevations, above 8,000 feet (2,500
meters) in the Greater Yellowstone Ecosystem and 6,400 feet (1,942 meters) in
the Northern Continental Divide Ecosystem, and on slopes ranging from 30 to 60
degrees. In the Cabinet-Yaak Ecosystem, the majority of den sites occurred
above 5,248 feet (1,600 meters), often on northerly and easterly aspects,
though all aspects were used. In the Selkirks Ecosystem, the majority of dens
were located above 5,248 feet (1,600 meters), often on easterly aspects, but
all aspects were used. The North Cascades Ecosystem contains large areas at
high elevations with isolated, steep, snow-packed slopes and many natural
caves to serve as potential den sites. Additional areas associated with ridge
systems stemming from major volcanic peaks may provide den sites at lower
elevations within the North Cascades. In 1991, Davis and Butterfield assessed
the northern part of the Bitterroot Ecosystem recovery zone and areas to the
immediate north, and concluded that deep snow and mountainous terrain provides
adequate denning habitat.
Denning increases survival during periods of food scarcity and inclement
weather. During this period, bears do not eat, drink, urinate or defecate.
Hibernating grizzly bears exhibit a marked decline in heart and respiration
rate, but only a slight drop in body temperature. Due to their relatively
constant body temperature in the den, hibernating grizzly bears may be aroused
and have been known to exit or relocate dens when disturbed by seismic or
mining activity or other human activities. Dens are rarely used twice by an
individual, although individuals usually use the same general area from year-
to-year. Females display stronger area fidelity than males and generally stay
in their dens longer, depending on reproductive status. Females with cubs
usually spend a few weeks close to their den upon emergence, unlike solitary
bears.
## Geography
Characteristics
Range
Adult grizzly bears are normally solitary except when breeding or when females
have dependent young, but they are not territorial and home ranges of adult
bears frequently overlap. Home range size is affected by resource
availability, sex, age and reproductive status. Generally, females with cubs-
of-the-year or yearlings have the smallest home range sizes. The large home
ranges of grizzly bears, particularly males, enhance maintenance of genetic
diversity in the population by enabling males to mate with numerous females.
Young, female grizzly bears usually establish home ranges within or
overlapping their mother’s. This pattern of home range establishment can make
dispersal of females across landscapes a slow process. Radio-telemetry and
genetic data suggest females typically establish home ranges an average of 6.1
to 8.9 miles (9.8 to 14.3 kilometers) away from the center of their mother’s
home range, whereas males generally disperse farther, averaging 18.6 to 26.0
miles (29.9 to 42.0 kilometers) away from the center of their mother’s home
range. Maximum male dispersal distances of 42 to 109 miles (67 to 176
kilometers) have been documented in the Greater Yellowstone and Northern
Continental Divide ecosystems. Studies also indicate that females can and do
disperse long distances up to 50 to 56 miles (80 to 90 kilometers), typically
on the periphery of expanding populations. Although the frequency of long-
distance dispersal by females is much lower than males, it can contribute to
range expansion and demographic connectivity between populations.
Home range sizes vary among the ecosystems because of population densities and
habitat productivity, as well as methodology. In the 48 contiguous states,
observed average annual adult female home ranges vary from 130 to 358
kilometers-squared and average annual adult male home range vary from 475 to
2,162 kilometers-squared.
[ Launch Interactive Map ](/species/grizzly-bear-ursus-arctos-horribilis/map)
### Timeline
Explore the information available for this taxon's timeline. You can select an
event on the timeline to view more information, or cycle through the content
available in the carousel below.
60 Items
Key:
Event
Regulatory Status Change
Working with others to conserve, protect and enhance fish, wildlife, plants
and their habitats for the continuing benefit of the American people.
## Footer Menu - Employment
* [ Careers & Internships ](/careers)
* [ Contracting ](/program/contracting)
## Footer Menu - Site Links
* [ Leadership ](/about/leadership)
* [ Frequently Asked Questions ](/frequently-asked-questions "Questions from the customer service call center")
* [ Contact FWS ](/contact-us)
## Footer Menu - Legal
* [ Accessibility ](/carp/help/accessibility)
* [ Freedom of Information Act ](/carp/program/fws-freedom-information-act-foia)
* [ Notices ](/carp/notices)
* [ Privacy Policy ](https://www.doi.gov/privacy)
* [ Disclaimers ](/carp/disclaimer)
* [ Information Quality ](/carp/program/information-quality)
* [ Vulnerability Disclosure Policy ](/carp/vulnerability-disclosure-policy)
## Footer Menu - External Links
* [ DOI ](https://www.doi.gov)
* [ USA.GOV ](https://www.usa.gov)
* [ ](https://www.facebook.com/usfws "Follow us on Facebook")
* [ ](https://www.instagram.com/usfws "Follow us on Instagram")
* [ ](https://www.twitter.com/usfws "Follow us on Twitter")
* [ ](https://www.linkedin.com/company/usfws "Find us on LinkedIn")
* [ ](https://www.flickr.com/photos/usfwshq "Find us on Flickr")
* [ ](https://www.youtube.com/usfws "Follow us on YouTube")
### You are exiting the U.S. Fish and Wildlife Service website
You are being directed to [ ]()
We do not guarantee that the websites we link to comply with Section 508
(Accessibility Requirements) of the Rehabilitation Act. Links also do not
constitute endorsement, recommendation, or favoring by the U.S. Fish and
Wildlife Service.
[ I Understand. Take me there. ]() Cancel
| biology | 1024655 | https://sv.wikipedia.org/wiki/Leadbeaters%20falanger | Leadbeaters falanger | Leadbeaters falanger (Gymnobelideus leadbeateri) är ett pungdjur som tillhör familjen flygpungekorrar. Trots släktskapet saknar den flygförmåga. Djuret påminner mer om vanliga ekorrar.
Djurets namn syftar på John Leadbeater, en biolog som sysslade med taxonomi vid Museum of Victoria.
Utbredning
Arten förekommer i ett mindre 3 500 km² stort området i östra delen av den australiska delstaten Victoria.
Utseende
Pälsen är på ovansidan gråbrun och har en svart längsgående strimma, undersidan är ljusare till gulaktig. Ytterligare två strimmor finns i ansiktet från ögonen till öronen. Djuret når en kroppslängd mellan 15 och 17 centimeter samt en vikt mellan 120 och 165 gram. Därtill kommer en yvig svans på omkring 20 centimeters längd som inte är en gripsvans. Arten har korta klor vid varje tå och honans pung (marsupium) är väl utvecklad.
Ekologi
Leadbeaters falanger är aktiv på natten och lever i träd. Habitatet utgörs av kyliga fuktiga skogar upp till 1 500 meter över havet. Bon där de föder ungar byggs ofta i eukalyptusträd med håligheter och ligger vanligen 10 till 30 meter över marken.
Individerna lever i små grupper som vanligen består av en vuxen hona, en till tre hannar och deras ungar. Varje grupp har ett revir som är en till två hektar stort. Hos Leadbeaters falanger är honor det dominanta könet, alfahonan försvarar territoriet mot andra honor och parar sig bara med en av de könsmogna hannarna. Hannar är mindre aggressiva mot artfränder av samma kön.
Föda
Födan utgörs främst av insekter och trädens vätskor. De äter bland annat skalbaggar, spindlar och andra leddjur men gnager även på akacieträdens bark för att komma åt bastskiktet och kåda.
Fortplantning
Med undantag av de hetaste sommarmånaderna (januari, februari) kan honor para sig hela året. Dräktigheten är med 15 till 17 dagar ganska kortvarig (även för pungdjur). Per kull föds vanligen ett eller två ungdjur. Efter födelsen lever ungarna tre månader i pungen. Sedan stannar de 5 till 40 dagar i gruppens bo och deltar i utflykter. Efter 10 till 15 månader sluter honan att ge di och efter cirka två år är ungarna könsmogna. Livslängden i naturen kan vara 7,5 år och med människans vård upp till 9 år.
Leadbeaters falanger och människor
Arten upptäcktes för första gången under 1800-talet nära Melbourne. Efter 1909 registrerades en längre tid inga iakttagelser och därför antogs att djuret är utdött men 1961 upptäcktes arten igen.
På grund av arten krav på eukalyptusträd med håligheter är de känsliga för människans inverkning. Flera träd röjs eller förstörs under skogsbränder. Dessutom tar det 150 år innan ett nytt eukalyptusträd är tillräckligt stort.
Enligt uppskattningar finns bara 5000 individer kvar och det befaras att beståndet minskar ytterligare. IUCN listar arten som starkt hotad (endangered).
Referenser
Noter
Tryckta källor
Macdonald, David W. (red.), (1984) Jordens Djur 5: Pungdjuren, fladdermössen, insektätarna m.fl.. Stockholm: Bonnier Fakta. s. 130,
Ronald M. Nowak: Walker’s Mammals of the World. Johns Hopkins University Press, Baltimore/London 1999.
Externa länkar
Fåframtandade pungdjur
Däggdjur i australiska regionen | swedish | 0.807001 |
mouldy_food_sick/mouldy-food-safe-eat-theresa-may-jam-bread-cheese-meat-fruit-vegetables-a8777181.html.txt | ## Stay up to date with notifications from The Independent
Notifications can be managed in browser preferences.
Not now Yes please
Jump to content
#### Asia Edition Change
UK Edition US Edition Edición en Español
Sign up to our newsletters Subscribe now
{{indy.truncatedName}}
Log in / Register
Independent
Jet2holidays Best betting sites
Subscribe Menu
* News
* News
* UK
* US
* World
* UK Politics
* Brexit
* Health
* Business
* Science
* Space
* News Videos
* Sport
* Sport
* Football
* Paris 2024 Olympics
* Formula 1
* Rugby Union
* Cricket
* Tennis
* Boxing
* UFC
* Cycling
* Golf
* Betting
* Sport Videos
* Voices
* Voices
* Editorials
* Letters
* John Rentoul
* Mary Dejevsky
* Andrew Grice
* Sean O’Grady
* Culture
* Culture
* Film
* TV & Radio
* Music
* Games
* Books
* Art
* Photography
* Theatre & Dance
* Culture Videos
* Lifestyle
* Lifestyle
* Shopping
* Tech
* Money
* Food & Drink
* Fashion
* Love & Sex
* Women
* Health & Families
* Royal Family
* Motoring
* Electric Vehicles
* Car Insurance deals
* Lifestyle Videos
* Travel
* Travel
* UK Hotel Reviews
* News & Advice
* Simon Calder
* Cruises
* UK
* Europe
* USA
* Asia
* Australia & New Zealand
* South America
* C. America & Caribbean
* Middle East
* Premium
* Premium
* Politics Explained
* Editorials
* Voices
* Long Reads
* News Analysis
* Today’s Edition
More
Best
* Advisor
* Home & Garden
* Tech
* Broadband deals
* Fashion & Beauty
* Deals
* Food & Drink
* Kids
* Books
* Travel & Outdoors
* Sports & Fitness
Climate
* News
* Electric Vehicles
* Voices
* Sustainable Living
* Explained
* Climate Videos
* Solar Panels
* SGI
TV
* Behind The Headlines
* On The Ground
* Decomplicated
* You Ask The Questions
* Binge Watch
* Music Box
* Love Lives
* Travel Smart
* Watch on your TV
* Today’s Edition
* Crosswords & Puzzles
* Most Commented
* Newsletters
* Ask Me Anything
* Virtual Events
* Betting Sites
* Online Casinos
* Wine Offers
* Vouchers
* Indy100
### Thank you for registering
Please refresh the page or navigate to another page on the site to be
automatically logged in Please refresh your browser to be logged in
Lifestyle Food and Drink
# What mouldy foods are safe to eat?
##
Theresa May has admitted that she is happy to scrape mould off jam before
eating it
Sabrina Barr
Thursday 14 February 2019 13:06 GMT
Comments
#### Article bookmarked
Find your bookmarks in your Independent Premium section, under my profile
Don't show me this message again
✕
Those who got fewer calories from carbohydrates had higher risk of atrial
fibrillation ( Getty Images/iStockphoto )
### Sign up to IndyEat's free newsletter for weekly recipes, foodie features
and cookbook releases
### Get our food and drink newsletter for free
Please enter a valid email address
Please enter a valid email address
SIGN UP
I would like to be emailed about offers, events and updates from The
Independent. Read our privacy policy
## Thanks for signing up to the
IndyEats email
{{ #verifyErrors }} {{ message }} {{ /verifyErrors }} {{ ^verifyErrors }}
Something went wrong. Please try again later {{ /verifyErrors }}
During a recent cabinet discussion about food waste , prime minister
Theresa May admitted that she doesn't dispose of jam when it's grown mould
, rather scrapes the mould off and consumes the jam underneath.
The conversation over May's culinary habits has sparked a nationwide debate,
prompting some to commend the prime minister for making a conscious effort to
reduce waste.
Others have expressed their disgust over the idea of eating food that's
previously gone mouldy.
"Theresa May scraping the mould off jam is the most painfully accurate Brexit
metaphor we could get six weeks before leave day," one person tweeted .
It also provoked a discussion about which foods are and aren't safe to eat if
they've grown mould.
For example, foods that have a high water content, such as cooked pasta and
soft fruits, are not safe to eat if they've grown mould, as the mould can
easily contaminate the food items below the surface.
## Six healthy breakfast recipes to try
Show all 6
### 1 / 6 Six healthy breakfast recipes to try
### Six healthy breakfast recipes to try
You will need: 1 onion, 1 red pepper, 1 stick of celery, 1 cup of mushrooms, 4
to 6 eggs, 1 habanero chilli (optional), 1 tablespoon of oil, 25g of grated
low-fat cheese, 150 ml of skimmed milk, 50g of turkey breast. Add some spinach
for an extra boost.
Method:
1) Cook your turkey breast so that it’s ready to add to the mix later on. Best
to grill it and then chop it up as it’s healthier than shallow frying. 2)
Meanwhile, heat the oil and add your onion, pepper, chilli, mushrooms and
celery to your pan. Cook these for around five minutes until your veg is nice
and soft. 3) Whisk your eggs and milk together in a separate bowl, seasoning
with salt and pepper. 4) Add the egg mixture, veg, cooked turkey and cheese to
a high-sided baking pan or tin and cook in your oven for around 15 minutes at
170C.
DW Fitness Clubs
### Six healthy breakfast recipes to try
Be careful when you buy your porridge, as some brands will cram a lot of sugar
in there. Porridge is a good breakfast option as it is renowned for releasing
energy slowly, which means you can get to lunch without suffering from a lull.
A great source of fibre, potassium and vitamins, bananas are always a good
accompaniment to your morning oats.
DW Fitness Clubs
### Six healthy breakfast recipes to try
Ingredients: 2 full eggs, 3 egg whites, asparagus, peppers, 50g of smoked
salmon
Method
1) Boil your asparagus in water for around five minutes. 2) Meanwhile, mix
your eggs and egg whites in a jug, and add a splash of skimmed milk. Chop some
peppers up and throw them in too. 3) Once your asparagus is cooked, drain it
and chop into smaller chunks. Add these to your egg mixture. 4) Whisk your
mixture and season with salt and pepper. 5) Pour the mix into a hot pan with a
small knob of butter or a teaspoon of quality olive oil. 6) Cook the omelette
for around 90 seconds to two minutes. 7) Once the bottom is cooked, take the
pan off the hob and place under the grill for another 30 seconds to a minute
in order to cook the top. 8) Serve with your smoked salmon.
DW Fitness
### Six healthy breakfast recipes to try
Greek yoghurt has vast nutritional benefits. Regardless of where you stand on
the superfood debate, Greek yoghurt’s credentials speak for themselves. A good
source of potassium, protein, calcium and essential vitamins, this food forms
an ideal base for a healthy breakfast, especially if you’re trying to lose
weight.
DW Fitness
### Six healthy breakfast recipes to try
Eggs Florentine is not only a tasty breakfast, it also carries a hefty
nutritional punch, particularly when you throw some spinach into the equation.
DW Fitness
### Six healthy breakfast recipes to try
So fast and easy to make, yet so effective. Wholemeal toast can be a good
breakfast choice, as long as you are sensible with your toppings. Peanut
butter is perfect. A good source of “healthy fats”, as well as protein and
Vitamin E among other nutrients, a liberal spreading of peanut butter can set
you up for the day.
DW Fitness
The Food Standards Authority (FSA) offers advice on when foods are and are not
safe to eat if they've grown mould.
"We advise not to eat food that is obviously rotten or containing mould due to
potential risks from the mould," they state. This advice is especially
important for people in vulnerable groups, which includes children, the
elderly, pregnant women and those who have a weakened immune system.
"While it is possible that removing the mould and a significant amount of the
surrounding product could remove any unseen toxins that are present, there is
no guarantee that doing so would remove them all."
Here's a list of foods that are safe and unsafe to eat when they've grown
mould:
## Foods you can eat:
### Hard salami and dry-cured hams
According to the United States Department of Agriculture ( USDA ), it is
perfectly normal for foods stored at room temperature such as hard salami and
dry-cured country hams to sometimes have mould on the surface.
As such, it's safe to scrape the mould from the surface and consume the meat
underneath.
### Hard cheese
When hard cheeses such as parmesan and Grana Padano grow mould, it's unlikely
that it would penetrate deep underneath the surface of the cheese, the USDA
explains.
When consuming a hard cheese that has mould on it, you should cut off at least
one inch around the mould, making sure that the knife you're using doesn't
come into contact with the mould.
Recommended
* Chuck E Cheese’s denies serving leftover pizza despite YouTuber claim
Once the mould has been removed, you should then cover the cheese in a new
plastic wrapping when storing it.
According to the American Cheese Society , the recommended temperature for
storing cheese is between 1C and 7C, ideally at the bottom of a vegetable or
fruit drawer in the fridge.
### Cheese that's made with mould
(Getty Images/iStockphoto ( Getty Images/iStockphoto )
Certain cheeses, such as Gorgonzola, Stilton and Roquefort, are made using
mould.
If a cheese contains a mould that was included in the manufacturing process,
then it's safe to eat.
### Firm fruits and vegetables
While it isn't advisable to eat soft fruits and vegetables that have grown
mould, it can be ok when consuming firm produce such as carrots, bell peppers
and cabbage.
"If the food is hard like pumpkin and has a low water content, then you can
safely cut the mould off, providing you cut at least one centimetre off around
where the mould is," outlines New Zealand environmental organisation Love
Food Hate Waste .
When fruits and vegetables that are firm have a low water content, this
hinders the mould from penetrating too deeply below the surface.
Recommended
* You can buy a pastry that's a mix between a croissant and waffle
The FSA advises avoiding any fruits and vegetables that are obviously
rotten/mouldy due to risks from the mould, as toxins may penetrate below the
surface.
"However, if fruit/vegetables are a bit overripe (for example wrinkly apples
and carrots, brown bananas, slightly mushy strawberries) it is fine to use
them in cooking/smoothies/cakes," they add.
## Foods you should be wary of
### Luncheon and cooked leftover meat
Foods that have a high water content, such as luncheon meats or cooked
leftover meat, can be harmful to eat if they've grown mould on them.
"Food with high moisture content can be contaminated below the surface," the
USDA states.
"Mouldy foods may also have bacteria growing along with the mould."
### Cooked grains or pasta
This same rule applies to cooked grains and pasta, which have a high water
content.
### Soft cheese
While some cheeses are safe to eat when they've grown mould, such as hard
cheeses or cheeses manufactured with mould, the same doesn't go for all
cheeses.
When mould appears on soft cheeses such as Brie and Camembert that weren't
included in the manufacturing process, then it's recommended to discard the
cheeses immediately.
### Jam
(Getty Images ( Getty Images )
Prime minister Theresa May's recent admission that she removes mould from jam
before eating it sparked a huge online debate about the practice.
The USDA advises throwing away jam if it's grown mould, as the mould could
produce a mycotoxin, which is a toxic substance produced by fungus that would
be detrimental to consume.
"Microbiologists recommend against scooping out the mould and using the
remaining condiment," the USDA states.
Recommended
* The biggest vegan food launches of 2019 so far
However, official advice on the health concerns surrounding the practice
varies.
In 2014, mould expert Dr Patrick Hickey informed the BBC that it is safe to
scrape mould off jam before eating the condiment underneath.
### Yogurt
As a food item with a high water content, it isn't advisable to eat yogurt on
which mould has started growing.
### Soft fruits and vegetables
While mould can be safely removed from firm fruits and vegetables, this same
tactic doesn't apply to soft fruits and vegetables such as peaches, tomatoes
and cucumbers due to the high water content of the foods.
### Bread
(Getty Images/iStockphoto ( Getty Images/iStockphoto )
Leavened bread, containing raising agents such as yeast, contains air pockets
that are formed following the fermentation process.
Due to the porous nature of bread, mould can easily spread and contaminate
below its surface.
"Bread should be safe to consume past its ‘Best Before’ date but consumers
should not eat bread that is mouldy, or remove mould and consume the rest,"
advises the FSA.
"While consumers may not wish to consume stale bread, it can be used safely in
some recipes."
Support free-thinking journalism and attend Independent events
### Nuts
While many people may eat nuts on a daily basis due to the health benefits of
the nutritious snack, it's important to be wary not to do so if they've grown
mould.
"Foods processed without preservatives are at high risk for mould," the USDA
explains.
Nuts and seeds that have been roasted or salted are more likely to contain
preservatives and therefore have a lower risk of developing mould.
### More about
mould Food Eat wellbeing
## Join our commenting forum
Join thought-provoking conversations, follow other Independent readers and see
their replies
Comments
### 1 / 4 What mouldy foods are safe to eat?
### What mouldy foods are safe to eat?
(Getty Images/iStockphoto
Getty Images/iStockphoto
### What mouldy foods are safe to eat?
(Getty Images
Getty Images
### What mouldy foods are safe to eat?
(Getty Images/iStockphoto
Getty Images/iStockphoto
### What mouldy foods are safe to eat?
Theresa May has admitted that she is happy to scrape mould off jam before
eating it
✕
### Subscribe to Independent Premium to bookmark this article
Want to bookmark your favourite articles and stories to read or reference
later? Start your Independent Premium subscription today.
Subscribe
Already subscribed? Log in
### Most Popular
### Popular videos
###
### Sponsored Features
* Get in touch
* Contact us
* * Our Products
* Subscribe
* Register
* Newsletters
* Today’s Edition
* Install our app
* Archive
* Other publications
* International editions
* Independent en Español
* Independent Arabia
* Independent Turkish
* Independent Persian
* Independent Urdu
* Evening Standard
* Extras
* Advisor
* Puzzles
* All topics
* Betting Offers
* Voucher codes
* Competitions and offers
* Independent Advertising
* Independent Ignite
* Syndication
* Working at The Independent
* Legal
* Code of conduct and complaints
* Contributors
* Cookie policy
* Privacy notice
* User policies
* Modern Slavery Act
### Thank you for registering
Please refresh the page or navigate to another page on the site to be
automatically logged in Please refresh your browser to be logged in
Close
#### Asia Edition Change
UK Edition US Edition Edición en Español
Subscribe
{{indy.truncatedName}}
Log in / Register
Jet2holidays Best betting sites
{{#items}}
## {{#stampSmall}} {{/stampSmall}} {{#stampClimate}} {{/stampClimate}}
{{#stampPremium}} {{/stampPremium}} {{title}} {{#desc}} {{desc}}
{{/desc}}
{{#children}}
* {{title}}
{{/children}}
{{/items}}
* Today’s Edition
* Crosswords & Puzzles
* Most Commented
* Newsletters
* Ask Me Anything
* Virtual Events
* Betting Sites
* Online Casinos
* Wine Offers
* Vouchers
* Indy100
✕
Log in
Email address
Password
Email and password don't match
Submit
Forgotten your password?
New to The Independent?
Register
Or if you would prefer:
SIGN IN WITH GOOGLE
Want an ad-free experience?
View offers
This site is protected by reCAPTCHA and the Google Privacy notice and Terms
of service apply.
Hi {{indy.fullName}}
* My Independent Premium
* Account details
* Help centre
* Logout
| biology | 4504832 | https://sv.wikipedia.org/wiki/Platymiscium%20pubescens | Platymiscium pubescens | Platymiscium pubescens är en ärtväxtart som beskrevs av Marc Micheli. Platymiscium pubescens ingår i släktet Platymiscium och familjen ärtväxter. Inga underarter finns listade i Catalogue of Life.
Bildgalleri
Källor
Externa länkar
Ärtväxter
pubescens | swedish | 1.275696 |
mouldy_food_sick/Aflatoxin.txt | Aflatoxins are various poisonous carcinogens and mutagens that are produced by certain molds, particularly Aspergillus species mainly by Aspergillus flavus and Aspergillus parasiticus. According to the USDA, "They are probably the best known and most intensively researched mycotoxins in the world." The fungi grow in soil, decaying vegetation and various staple foodstuffs and commodities such as hay, maize, peanuts, coffee, wheat, millet, sorghum, cassava, rice, chili peppers, cottonseed, tree nuts, sesame seeds, sunflower seeds, and various cereal grains and oil seeds. In short, the relevant fungi grow on almost any crop or food. When such contaminated food is processed or consumed, the aflatoxins enter the general food supply. They have been found in both pet and human foods, as well as in feedstocks for agricultural animals. Animals fed contaminated food can pass aflatoxin transformation products into milk, milk products, and meat. For example, contaminated poultry feed is the suspected source of aflatoxin-contaminated chicken meat and eggs in Pakistan.
Children are particularly vulnerable to aflatoxin exposure, which is linked to immune suppression, stunted growth, delayed development, aflatoxicosis, food spoilage and liver cancer. Some studies have reported an association between childhood stunting and aflatoxin exposure, although this link has not been consistently detected in all studies. but could not be detected in all. Furthermore, a causal relationship between childhood stunting and aflatoxin exposure has yet to be conclusively shown by epidemiological studies, though such investigations are underway. Adults have a higher tolerance to exposure, but are also at risk. No animal species is known to be immune. Aflatoxins are among the most carcinogenic substances known. After entering the body, aflatoxins may be metabolized by the liver to a reactive epoxide intermediate or hydroxylated to become the less harmful aflatoxin M1.
Aflatoxin poisoning most commonly results from ingestion, but the most toxic aflatoxin compound, B1, can permeate through the skin.
The United States Food and Drug Administration (FDA) action levels for aflatoxin present in food or feed is 20 to 300 ppb. The FDA has had occasion to declare both human and pet food recalls as a precautionary measure to prevent exposure.
The term "aflatoxin" is derived from the name of the species Aspergillus flavus, in which some of the compounds first were discovered. A new disease was identified with unknown characteristics in England during the 1950s and 1960s, which increased turkey mortality. Later, aflatoxin was recognized in 1960 in England as a causative agent of the mysterious Turkey ‘X’ disease that causes excessive mortality in turkey poults. Aflatoxins form one of the major groupings of mycotoxins, and apart from Aspergillus flavus various members of the group of compounds occur in species such as: Aspergillus parasiticus, Aspergillus pseudocaelatus, Aspergillus pseudonomius, and Aspergillus nomius.
Major types and their metabolites[edit]
Aflatoxin B1 is considered the most toxic and is produced by both Aspergillus flavus and Aspergillus parasiticus. Aflatoxin M1 is present in the fermentation broth of Aspergillus parasiticus, but it and aflatoxin M2 are also produced when an infected liver metabolizes aflatoxin B1 and B2.
Aflatoxin B1 and B2 (AFB), produced by A. flavus and A. parasiticus
Aflatoxin G1 and G2 (AFG), produced by some Group II A. flavus and Aspergillus parasiticus
Aflatoxin M1 (AFM1), metabolite of aflatoxin B1 in humans and animals (exposure in ng levels may come from a mother's milk)
Aflatoxin M2, metabolite of aflatoxin B2 in milk of cattle fed on contaminated foods
Aflatoxicol (AFL): metabolite produced by breaking down the lactone ring
Aflatoxin Q1 (AFQ1), major metabolite of AFB1 in in vitro liver preparations of other higher vertebrates
AFM, AFQ, and AFL retain the possibility to become an epoxide. Nevertheless, they appear much less capable of causing mutagenesis than the unmetabolized toxin.
Contamination conditions[edit]
Aflatoxins are produced by both Aspergillus flavus and Aspergillus parasiticus, which are common forms of 'weedy' molds widespread in nature. The presence of those molds does not always indicate that harmful levels of aflatoxin are present, but does indicate a significant risk. The molds can colonize and contaminate food before harvest or during storage, especially following prolonged exposure to a high-humidity environment, or to stressful conditions such as drought. Aflatoxin contamination is increasing in crops such as maize as a result of climate change creating better conditions for these molds.
The native habitat of Aspergillus is in soil, decaying vegetation, hay, and grains undergoing microbiological deterioration, but it invades all types of organic substrates whenever conditions are favorable for its growth. Favorable conditions for production of aflatoxins include high moisture content (at least 7%) and temperatures from 55 °F (13 °C) to 104 °F (40 °C) [optimum 27 to 30 °C (81 to 86 °F)]. Aflatoxins have been isolated from all major cereal crops, and from sources as diverse as peanut butter and cannabis. The staple commodities regularly contaminated with aflatoxins include cassava, chilies, corn, cotton seed, millet, peanuts, rice, sorghum, sunflower seeds, tree nuts, wheat, and a variety of spices intended for human or animal consumption. Aflatoxin transformation products are sometimes found in eggs, milk products, and meat when animals are fed contaminated grains.
A study conducted in Kenya and Mali found that the predominant practices for drying and storage of maize were inadequate in minimizing exposure to aflatoxins.
Organic crops, which are not treated with fungicides, may be more susceptible to contamination with aflatoxins.
Prevention[edit]
A primary means of limiting risk from aflatoxins in the food supply is food hygiene in the commercial commodity supply chain, such as rejecting moldy grain for use in food processing plants and testing of batches of ingredients for aflatoxin levels before adding them to the mix. Regulatory agencies such as the FDA set limits on acceptable levels. Grain drying itself, which is necessary for viable combine harvesting in many regions, lays the fundamentals for this effort by preventing stored grain from being too damp in the first place.
There is very limited evidence to show that agricultural and nutritional education can reduce exposure to aflatoxin in low to middle income countries.
Pathology[edit]
No animal species is known to be immune to the acute toxic effects of aflatoxins. Adult humans have a high tolerance for aflatoxin exposure and rarely succumb to acute aflatoxicosis, but children are particularly affected, and their exposure can lead to stunted growth and delayed development, in addition to all the symptoms mentioned below.
High-level aflatoxin exposure produces an acute hepatic necrosis (acute aflatoxicosis), resulting later in cirrhosis or carcinoma of the liver. Acute liver failure is made manifest by bleeding, edema, alteration in digestion, changes to the absorption and/or metabolism of nutrients, and mental changes and/or coma.
Chronic, subclinical exposure does not lead to symptoms so dramatic as acute aflatoxicosis. Chronic exposure increases the risk of developing liver and gallbladder cancer, as aflatoxin metabolites may intercalate into DNA and alkylate the bases through epoxide moiety. This is thought to cause mutations in the p53 gene, an important gene in preventing cell cycle progression when there are DNA mutations, or signaling apoptosis (programmed cell death). These mutations seem to affect some base pair locations more than others, for example, the third base of codon 249 of the p53 gene appears to be more susceptible to aflatoxin-mediated mutations than nearby bases. As with other DNA-alkylating agents, Aflatoxin B1 can cause immune suppression, and exposure to it is associated with an increased viral load in HIV positive individuals.
The expression of aflatoxin-related diseases is influenced by factors such as species, age, nutrition, sex, and the possibility of concurrent exposure to other toxins. The main target organ in mammals is the liver, so aflatoxicosis primarily is a hepatic disease. Conditions increasing the likelihood of aflatoxicosis in humans include limited availability of food, environmental conditions that favour mould growth on foodstuffs, and lack of regulatory systems for aflatoxin monitoring and control.
A regular diet including apiaceous vegetables, such as carrots, parsnips, celery, and parsley may reduce the carcinogenic effects of aflatoxin.
There is no specific antidote for aflatoxicosis. Symptomatic and supportive care tailored to the severity of the liver disease may include intravenous fluids with dextrose, active vitamin K, B vitamins, and a restricted, but high-quality protein diet with adequate carbohydrate content.
In other animals[edit]
In dogs, aflatoxin has potential to lead to liver disease. Low levels of aflatoxin exposure require continuous consumption for several weeks to months in order for signs of liver dysfunction to appear. Some articles have suggested the toxic level in dog food is 100–300 ppb and requires continuous exposure or consumption for a few weeks to months to develop aflatoxicosis. No information is available to suggest that recovered dogs will later succumb to an aflatoxin-induced disease.
Turkeys are extremely susceptible to aflatoxicosis. Recent studies have revealed that this is due to the efficient cytochrome P450 mediated metabolism of aflatoxin B1 in the liver of turkeys and deficient glutathione-S-transferase mediated detoxification.
Some studies on pregnant hamsters showed a significant relationship between exposure of aflatoxin B1 (4 mg/kg, single dose) and the appearance of developmental anomalies in their offspring.
In 2005, Diamond Pet Foods discovered aflatoxin in a product manufactured at their facility in Gaston, South Carolina. In 23 states, Diamond voluntarily recalled 19 products formulated with corn and manufactured in the Gaston facility. Testing of more than 2,700 finished product samples conducted by laboratories confirmed that only two date codes of two adult dog formulas had the potential to be toxic.
In December 2020 and January 2021, Midwestern Pet Foods recalled dog food that contained fatal levels of aflatoxin. As many as 70 dogs had died from aflatoxin poisoning by January 12, 2021.
Detection in humans[edit]
There are two principal techniques that have been used most often to detect levels of aflatoxin in humans.
The first method is measuring the AFB1-guanine adduct in the urine of subjects. The presence of this breakdown product indicates exposure to aflatoxin B1 during the past 24 hours. This technique measures only recent exposure, however. Due to the half-life of this metabolite, the level of AFB1-guanine measured may vary from day to day, based on diet, it is not ideal for assessing long-term exposure.
Another technique that has been used is a measurement of the AFB1-albumin adduct level in the blood serum. This approach provides a more integrated measure of exposure over several weeks or months.
List of outbreaks[edit]
This section needs expansion. You can help by adding to it. (December 2014)
International sources of commercial peanut butter, cooking oils (e.g. olive, peanut and sesame oil), and cosmetics have been identified as contaminated with aflatoxin. In some instances, liquid chromatography–tandem mass spectrometry (LC–MS/MS), and other analytical methods, revealed a range from 48% to 80% of selected product samples as containing detectable quantities of aflatoxin. In many of these contaminated food products, the aflatoxin exceeded the safe limits of the U.S. Food and Drug Administration (FDA), or other regulatory agency.
1960 Outbreak of Turkey ‘X’ disease in England and Aflatoxin discovery
1961 Identified Aspergillus flavus associated with toxicity of groundnuts
1962 Studies conducted on physicochemical properties of aflatoxins, Aflatoxin B and G identified in TLC analysis, and Isolation and synthesis of crystalline aflatoxins.
1963 Aflatoxin B2, G1, and G2 were identified and chemically characterized as Difurocoumarin derivatives
1965 FDA approved the first regulation on aflatoxins 30 μg/kg
1966 Milk toxins were designated as AFM1 and AFM2 and AFM1 was detected in Milk, Urine, Kidney, and liver
1973 Poland: 10 died following the opening of the tomb of Casimir IV Jagiellon, which contained aflatoxin-producing molds.
2004 Kenya: acute outbreak of aflatoxicosis resulting from ingestion of contaminated maize, 125 confirmed deaths.
February–March 2013: Romania, Serbia, Croatia imported into western Europe – 2013 aflatoxin contamination.
February 2013: Iowa contamination.
2014 (ongoing): Nepal and Bangladesh, neonatal exposures, found in umbilical cord blood.
2019 Kenya: five brands of maize flour recalled due to contamination.
2021 USA: Contamination of pet food manufactured by Midwestern Pet Food, causing the deaths of at least 70 dogs.
2021 Sri Lanka: contaminated coconut oil released for public consumption by local government.
2024 South Africa: The National Consumer Commission recalled various peanut butter brands due to contamination
See also[edit]
Aflatoxin total synthesis
2013 aflatoxin contamination
Mycotoxins in animal feed
Nixtamalization
Sterigmatocystin, a related toxin
Other ways in which aspergillus can cause disease in mammals:
Aspergillosis
Primary cutaneous aspergillosis
Resources[edit]
^ Ramdas Kodape, Anup; Raveendran, Ashika; Shivegowda Vivek Babu, Chikkarasanahalli (2022-11-30), Claude Assaf, Jean (ed.), "Aflatoxins: A Postharvest Associated Challenge and Mitigation Opportunities", Aflatoxins - Occurrence, Detection and Novel Detoxification Strategies, IntechOpen, doi:10.5772/intechopen.106333, ISBN 978-1-80356-884-3, retrieved 2024-04-02
^ Ramdas Kodape, Anup; Raveendran, Ashika; Shivegowda Vivek Babu, Chikkarasanahalli (2022-11-30), Claude Assaf, Jean (ed.), "Aflatoxins: A Postharvest Associated Challenge and Mitigation Opportunities", Aflatoxins - Occurrence, Detection and Novel Detoxification Strategies, IntechOpen, doi:10.5772/intechopen.106333, ISBN 978-1-80356-884-3, retrieved 2024-04-02
^ https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/molds-food-are-they-dangerous
^ Fratamico PM, Bhunia AK, Smith JL (2008). Foodborne Pathogens: Microbiology and Molecular Biology. Norofolk, UK: Horizon Scientific Press. ISBN 978-1-898486-52-7.
^ Iqbal SZ, et al. (2014). "Natural incidence of aflatoxins, ochratoxin A and zearalenone in chicken meat and eggs". Food Control. 43: 98–103. doi:10.1016/j.foodcont.2014.02.046.
^ Khlangwiset P, Shephard GS, Wu F (October 2011). "Aflatoxins and growth impairment: a review". Critical Reviews in Toxicology. 41 (9): 740–55. doi:10.3109/10408444.2011.575766. PMID 21711088. S2CID 19262759.
^ Abbas HK (2005). Aflatoxin and Food Safety. CRC Press. ISBN 978-0-8247-2303-3.
^ https://www.business.qld.gov.au/industries/farms-fishing-forestry/agriculture/biosecurity/animals/diseases/guide/aflatoxicosis#:~:text=Aflatoxicosis%20is%20a%20fungal%20toxicosis,without%20adequate%20drying%20and%20aeration
^ Kodape, Anup; Lama, Ankita; Vivek Babu, C.S. (April 2024). "Metagenomic insights of fungal diversity of peanuts under storage conditions and mitigation of aflatoxigenic fungi through competitive exclusion and phytochemicals". Food Bioscience. 58: 103711. doi:10.1016/j.fbio.2024.103711.
^ Voth-Gaeddert LE, Stoker M, Torres O, Oerther DB (April 2018). "Association of aflatoxin exposure and height-for-age among young children in Guatemala". International Journal of Environmental Health Research. 28 (3): 280–292. Bibcode:2018IJEHR..28..280V. doi:10.1080/09603123.2018.1468424. PMID 29706087. S2CID 23510545.
^ Turner PC, Collinson AC, Cheung YB, Gong Y, Hall AJ, Prentice AM, Wild CP (October 2007). "Aflatoxin exposure in utero causes growth faltering in Gambian infants". International Journal of Epidemiology. 36 (5): 1119–25. doi:10.1093/ije/dym122. PMID 17576701.
^ Mitchell NJ, Hsu HH, Chandyo RK, Shrestha B, Bodhidatta L, Tu YK, Gong YY, Egner PA, Ulak M, Groopman JD, Wu F (2017). "Aflatoxin exposure during the first 36 months of life was not associated with impaired growth in Nepalese children: An extension of the MAL-ED study". PLOS ONE. 12 (2): e0172124. Bibcode:2017PLoSO..1272124M. doi:10.1371/journal.pone.0172124. PMC 5315312. PMID 28212415.
^ Chen C, Mitchell NJ, Gratz J, Houpt ER, Gong Y, Egner PA, Groopman JD, Riley RT, Showker JL, Svensen E, Mduma ER, Patil CL, Wu F (March 2018). "Exposure to aflatoxin and fumonisin in children at risk for growth impairment in rural Tanzania". Environment International. 115: 29–37. doi:10.1016/j.envint.2018.03.001. PMC 5989662. PMID 29544138.
^ Smith LE, Prendergast AJ, Turner PC, Mbuya MN, Mutasa K, Kembo G, Stoltzfus RJ (December 2015). "The Potential Role of Mycotoxins as a Contributor to Stunting in the SHINE Trial". Clinical Infectious Diseases. 61 (Suppl 7): S733–7. doi:10.1093/cid/civ849. PMC 4657594. PMID 26602301.
^ Hoffmann, V.; Jones, K.; Leroy, J. L. (2018). "The impact of reducing dietary aflatoxin exposure on child linear growth: a cluster randomised controlled trial in Kenya". BMJ Global Health. 3 (6): e000983. doi:10.1136/bmjgh-2018-000983. PMC 6278920. PMID 30588341.
^ Hoffmann V, Jones K, Leroy J (December 2015). "Mitigating aflatoxin exposure to improve child growth in Eastern Kenya: study protocol for a randomized controlled trial". Trials. 16: 552. doi:10.1186/s13063-015-1064-8. PMC 4669614. PMID 26634701.
^ Hudler GW (1998). Magical Mushrooms, Mischievous Molds: The Remarkable Story of the Fungus Kingdom and Its Impact on Human Affairs. Princeton University Press. ISBN 978-0-691-07016-2.
^ Boonen J, Malysheva SV, Taevernier L, Diana Di Mavungu J, De Saeger S, De Spiegeleer B (November 2012). "Human skin penetration of selected model mycotoxins". Toxicology. 301 (1–3): 21–32. doi:10.1016/j.tox.2012.06.012. PMID 22749975.
^ "Guidance for Industry: Action Levels for Poisonous or Deleterious Substances in Human Food and Animal Feed". Food and Drug Administration. August 2000. Retrieved November 14, 2020.
^ Wannop CC (March 1961). "The Histopathology of Turkey "X" Disease in Great Britain". Avian Diseases. 5 (4): 371–381. doi:10.2307/1587768. JSTOR 1587768.
^ Ramdas Kodape, Anup; Raveendran, Ashika; Shivegowda Vivek Babu, Chikkarasanahalli (2022-11-30), Claude Assaf, Jean (ed.), "Aflatoxins: A Postharvest Associated Challenge and Mitigation Opportunities", Aflatoxins - Occurrence, Detection and Novel Detoxification Strategies, IntechOpen, doi:10.5772/intechopen.106333, ISBN 978-1-80356-884-3, retrieved 2024-04-02
^ J. Varga, J.C. Frisvad, R.A. Samson: "Two new aflatoxin producing species, and an overview of Aspergillus section Flavi", Stud Mycol. 2011 Jun 30; 69(1): 57–80. doi: 10.3114/sim.2011.69.05
^ Geiser DM, Dorner JW, Horn BW, Taylor JW (December 2000). "The phylogenetics of mycotoxin and sclerotium production in Aspergillus flavus and Aspergillus oryzae". Fungal Genetics and Biology. 31 (3): 169–79. doi:10.1006/fgbi.2000.1215. PMID 11273679. Archived from the original on 2021-01-26. Retrieved 2018-12-29.
^ Aflatoxin M2 product page from Fermentek
^ Smith JE, Sivewright-Henderson R (1991). Mycotoxins and animal foods. CRC Press. p. 614. ISBN 978-0-8493-4904-1.
^ Neal GE, Eaton DL, Judah DJ, Verma A (July 1998). "Metabolism and toxicity of aflatoxins M1 and B1 in human-derived in vitro systems". Toxicology and Applied Pharmacology. 151 (1): 152–8. doi:10.1006/taap.1998.8440. PMID 9705898.
^ Yu, Jina; Hennessy, David A; Tack, Jesse; Wu, Felicia (1 May 2022). "Climate change will increase aflatoxin presence in US Corn". Environmental Research Letters. 17 (5): 054017. Bibcode:2022ERL....17e4017Y. doi:10.1088/1748-9326/ac6435.
^ Battilani, P.; Toscano, P.; Van der Fels-Klerx, H. J.; Moretti, A.; Camardo Leggieri, M.; Brera, C.; Rortais, A.; Goumperis, T.; Robinson, T. (July 2016). "Aflatoxin B1 contamination in maize in Europe increases due to climate change". Scientific Reports. 6 (1): 24328. Bibcode:2016NatSR...624328B. doi:10.1038/srep24328. PMC 4828719. PMID 27066906.
^ "Risk of aflatoxin contamination increases with hot and dry growing conditions | Integrated Crop Management". crops.extension.iastate.edu. Retrieved 2021-06-13.
^ "Storing nuts at a low temperature (refrigeration) reduces aflatoxin levels and mold and yeast counts for 3–6 months | News | Postharvest – Fruits, Vegetables and Ornamentals". www.postharvest.biz. Retrieved 2021-06-13.
^ Pradeepkiran JA (December 2018). "Analysis of aflatoxin B1 in contaminated feed, media, and serum samples of Cyprinus carpio L. by high-performance liquid chromatography". Food Quality and Safety. 2 (4): 199–204. doi:10.1093/fqsafe/fyy013.
^ No chance for aflatoxins Archived October 17, 2015, at the Wayback Machine Rural 21, the International Journal for Rural Development, 3 April 2013. – The Aflacontrol project was conducted by IFPRI with scientists from CIMMYT, the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Directorate of Groundnut Research and other organizations. It sought to provide evidence of the cost-effectiveness of aflatoxin risk-reduction strategies along maize and groundnut value chains in Africa, and to understand what prevented adoption of these control strategies.
^ Tosun H, Arslan R (2013). "Determination of aflatoxin B1 levels in organic spices and herbs". TheScientificWorldJournal. 2013: 874093. doi:10.1155/2013/874093. PMC 3677655. PMID 23766719.
^ Visser ME, Schoonees A, Ezekiel CN, Randall NP, Naude CE (April 2020). "Agricultural and nutritional education interventions for reducing aflatoxin exposure to improve infant and child growth in low- and middle-income countries". The Cochrane Database of Systematic Reviews. 2020 (4): CD013376. doi:10.1002/14651858.cd013376.pub2. PMC 7141997. PMID 32270495.
^ Williams JH, Phillips TD, Jolly PE, Stiles JK, Jolly CM, Aggarwal D (November 2004). "Human aflatoxicosis in developing countries: a review of toxicology, exposure, potential health consequences, and interventions". The American Journal of Clinical Nutrition. 80 (5): 1106–22. doi:10.1093/ajcn/80.5.1106. PMID 15531656.
^ Nogueira L, Foerster C, Groopman J, Egner P, Koshiol J, Ferreccio C (May 2015). "Association of aflatoxin with gallbladder cancer in Chile". JAMA. 313 (20): 2075–7. doi:10.1001/jama.2015.4559. PMC 7169945. PMID 26010638.
^ Aguilar F, Hussain SP, Cerutti P (September 1993). "Aflatoxin B1 induces the transversion of G-->T in codon 249 of the p53 tumor suppressor gene in human hepatocytes". Proceedings of the National Academy of Sciences of the United States of America. 90 (18): 8586–90. Bibcode:1993PNAS...90.8586A. doi:10.1073/pnas.90.18.8586. PMC 47402. PMID 8397412.
^ Jolly PE, Inusah S, Lu B, Ellis WO, Nyarko A, Phillips TD, Williams JH (2013). "Association between high aflatoxin B1 levels and high viral load in HIV-positive people". World Mycotoxin Journal. 6 (3): 255–261. doi:10.3920/WMJ2013.1585. PMC 6750767. PMID 31534557.
^ "Common food fungus can accelerate onset of AIDS". digitaljournal.com. September 1, 2013.
^ Machida M, Gomi K, eds. (2010). Aspergillus: Molecular Biology and Genomics. Caister Academic Press. ISBN 978-1-904455-53-0.
^ Peterson S, Lampe JW, Bammler TK, Gross-Steinmeyer K, Eaton DL (September 2006). "Apiaceous vegetable constituents inhibit human cytochrome P-450 1A2 (hCYP1A2) activity and hCYP1A2-mediated mutagenicity of aflatoxin B1". Food and Chemical Toxicology. 44 (9): 1474–84. doi:10.1016/j.fct.2006.04.010. PMID 16762476.
^ Bingham AK, Phillips TD, Bauer JE (March 2003). "Potential for dietary protection against the effects of aflatoxins in animals". Journal of the American Veterinary Medical Association. 222 (5): 591–6. doi:10.2460/javma.2003.222.591. PMID 12619837.
^ Bastianello SS, Nesbit JW, Williams MC, Lange AL (December 1987). "Pathological findings in a natural outbreak of aflatoxicosis in dogs". The Onderstepoort Journal of Veterinary Research. 54 (4): 635–40. PMID 3444619.
^ Rawal S, Yip SS, Coulombe RA (August 2010). "Cloning, expression and functional characterization of cytochrome P450 3A37 from turkey liver with high aflatoxin B1 epoxidation activity". Chemical Research in Toxicology. 23 (8): 1322–9. doi:10.1021/tx1000267. PMID 20707407.
^ Rawal S, Coulombe RA (August 2011). "Metabolism of aflatoxin B1 in turkey liver microsomes: the relative roles of cytochromes P450 1A5 and 3A37". Toxicology and Applied Pharmacology. 254 (3): 349–54. doi:10.1016/j.taap.2011.05.010. PMID 21616088.
^ Goldblatt L (2012-12-02). Aflatoxin: Scientific Background, Control, and Implications. Elsevier. ISBN 9780323148498.
^ FDA Inspection Report-Diamond Gaston SC Plant 12/21/2005-1/19/2006.
^ 2005 Recall, FDA
^ AKC Standard Article Contaminated Diamond Pet Food Products and 'Best By' Dates Narrowed Akcstandard.com Archived July 7, 2011, at the Wayback Machine
^ Medicine, Center for Veterinary (2021-01-12). "FDA Alert: Certain Lots of Sportmix Pet Food Recalled for Potentially Fatal Levels of Aflatoxin". FDA.
^ Tyko, Kelly. "Dog food recall expands: More than 70 dogs have died and 80 pets sick after eating Sportsmix pet food". USA TODAY. Retrieved 2021-01-13.
^ Bao L, Trucksess MW, White KD (2010). "Determination of aflatoxins B1, B2, G1, and G2 in olive oil, peanut oil, and sesame oil". Journal of AOAC International. 93 (3): 936–42. doi:10.1093/jaoac/93.3.936. PMID 20629398.
^ Li FQ, Li YW, Wang YR, Luo XY (May 2009). "Natural occurrence of aflatoxins in Chinese peanut butter and sesame paste". Journal of Agricultural and Food Chemistry. 57 (9): 3519–24. doi:10.1021/jf804055n. PMID 19338351.
^ Mahoney N, Molyneux RJ (April 2010). "Rapid analytical method for the determination of aflatoxins in plant-derived dietary supplement and cosmetic oils". Journal of Agricultural and Food Chemistry. 58 (7): 4065–70. doi:10.1021/jf9039028. PMC 2858461. PMID 20235534.
^ Leong YH, Ismail N, Latiff AA, Manaf NA, Rosma A (1 January 2011). "Determination of aflatoxins in commercial nuts and nut products using liquid chromatography tandem mass spectrometry". World Mycotoxin Journal. 4 (2): 119–127. doi:10.3920/WMJ2010.1229.
^ Staff (19 May 2014). "Gdy otwarto grób królewski, zaczęła działać klątwa Jagiellończyka" [When the royal tomb was opened, the Jagiellon curse began its work]. Gazeta Krakowska. Retrieved 18 January 2023.
^ Probst, Claudia; Njapau, Henry; Cotty, Peter J. (2007-04-15). "Outbreak of an Acute Aflatoxicosis in Kenya in 2004: Identification of the Causal Agent". Applied and Environmental Microbiology. 73 (8): 2762–2764. Bibcode:2007ApEnM..73.2762P. doi:10.1128/AEM.02370-06. ISSN 0099-2240. PMC 1855601. PMID 17308181.
^ "Dog food recall underscores toxic danger in drought-hit U.S. corn". Reuters. February 25, 2013.
^ "Aflatoxin threat in Nepal, Bangladesh". SciDev.Net South Asia. 2014-12-17. Archived from the original on 2016-03-03. Retrieved 2016-10-17.
^ Mutahi B (2019-11-15). "How safe is Kenya's staple food?". Retrieved 2019-11-15.
^ "US pet food recalled after 70 dogs die and others fall sick". BBC News. 2021-01-14. Retrieved 2021-01-14.
^ "Coconut oil stocks containing aflatoxins in market". themorning.lk. 2021-03-26. Retrieved 2021-03-26.
External links[edit]
Look up aflatoxin in Wiktionary, the free dictionary.
Detailed listing and information on all Aspergillus mycotoxins
Aflatoxin, ICRISAT
Aspergillusflavus.org
Aflatoxins – Cancer-Causing Substance
Aflatoxin B1
vte
Toxins
cardiotoxin
cytotoxin
enterotoxin
hemotoxin
hepatotoxin
neurotoxin
phototoxin
Bacterial toxinsExotoxinGram positiveBacilliClostridium:
tetani
Tetanospasmin
Tetanolysin
perfringens
Alpha toxin
Enterotoxin
difficile
A
B
botulinum
Botox
other:
Anthrax toxin
Listeriolysin O
Cocci
Streptolysin
Leukocidin
Panton–Valentine leukocidin
Staphylococcus
Staphylococcus aureus alpha/beta/delta
Exfoliatin
Toxic shock syndrome toxin
Staphylococcal Enterotoxin B (SEB)
Actinomycetota
Cord factor
Diphtheria toxin
Gram negative
Shiga toxin/Verotoxin
E. coli heat-stable enterotoxin
Cholera toxin/Heat-labile enterotoxin
Pertussis toxin
Pseudomonas exotoxin
Extracellular adenylate cyclase
Mechanisms
type I
Superantigen
type II
Pore-forming toxin
type III
AB toxin/AB5
Endotoxin
Lipopolysaccharide
Lipid A
Bacillus thuringiensis delta endotoxin
Cry1Ac
Cry3Bb1
Other B. thuringiensis toxins
Cry6Aa
Cry34Ab1
Virulence factor
Clumping factor A
Fibronectin binding protein A
Mycotoxins
Aflatoxin
Amatoxin (alpha-amanitin, beta-amanitin, gamma-amanitin, epsilon-amanitin)
beta-Nitropropionic acid
Citrinin
Cytochalasin
Ergotamine
Fumonisin (Fumonisin B1, Fumonisin B2, Fumonisin B3, Fumonisin B4)
Gliotoxin
Ibotenic acid
Lolitrem B
Muscimol
Ochratoxin
Patulin
Phalloidin
Sterigmatocystin
Trichothecene
Vomitoxin
Zeranol
Zearalenone
Plant toxins
Amygdalin
Anisatin
Antiarin
Brucine
Chaconine
Cicutoxin
Coniine
Daphnin
Delphinine
Divicine
Djenkolic acid
Falcarinol
Gossypol
Helenalin
Ledol
Linamarin
Lotaustralin
Mimosine
Oenanthotoxin
Oleandrin
Persin
Protoanemonin
Pseudaconitine
Retronecine
Resiniferatoxin
Scopolamine
Solamargine
Solanidine
Solanine
Solasodamine
Solasodine
Solasonine
Solauricidine
Solauricine
Strychnine
Swainsonine
Tagetitoxin
Tinyatoxin
Tomatine
Toxalbumin
Abrin
Ricin
Tutin
Invertebrate toxinsScorpion:
Androctonus australis hector insect toxin
Charybdotoxin
Maurotoxin
Agitoxin
Margatoxin
Slotoxin
Scyllatoxin
Hefutoxin
HgeTx1
HsTx1
Lq2
Birtoxin
Bestoxin
BmKAEP
Phaiodotoxin
Imperatoxin
Pi3
spider:
Latrotoxin
Alpha-latrotoxin
CSTX
Cupiennins
PhTx3
Stromatoxin
Vanillotoxin
Huwentoxin
Mollusca:
Conotoxin
Eledoisin
Onchidal
Saxitoxin
Tetrodotoxin
Vertebrate toxinsFish:
Ciguatoxin
Tetrodotoxin
Amphibian:
(+)-Allopumiliotoxin 267A
Batrachotoxin
Bufotoxins
Arenobufagin
Bufotalin
Bufotenin
Cinobufagin
Marinobufagin
Epibatidine
Histrionicotoxin
Pumiliotoxin 251D
Samandarin
Samandaridine
Tarichatoxin
Zetekitoxin AB
Reptile/Snake venom:
Bungarotoxin
Alpha-Bungarotoxin
Beta-Bungarotoxin
Calciseptine
Taicatoxin
Calcicludine
Cardiotoxin III
note: some toxins are produced by lower species and pass through intermediate species
Category
vteConsumer food safetyAdulterants, food contaminants
3-MCPD
Aldicarb
Antibiotic use in livestock
Cyanide
Formaldehyde
HGH controversies
Lead poisoning
Melamine
Mercury in fish
Sudan I
Food additives
Flavorings
Monosodium glutamate (MSG)
Salt
Sugar
High-fructose corn syrup
Intestinal parasites and parasitic disease
Amoebiasis
Anisakiasis
Cryptosporidiosis
Cyclosporiasis
Diphyllobothriasis
Enterobiasis
Fasciolopsiasis
Fasciolosis
Giardiasis
Gnathostomiasis
Paragonimiasis
Toxocariasis
Toxoplasmosis
Trichinosis
Trichuriasis
Microorganisms
Botulism
Campylobacter jejuni
Clostridium perfringens
Cronobacter
Enterovirus
Escherichia coli O104:H4
Escherichia coli O157:H7
Hepatitis A
Hepatitis E
Listeria
Norovirus
Rotavirus
Salmonella
Vibrio cholerae
Pesticides
Chlorpyrifos
DDT
Lindane
Malathion
Methamidophos
Preservatives
Benzoic acid
Ethylenediaminetetraacetic acid (EDTA)
Sodium benzoate
Sugar substitutes
Acesulfame potassium
Aspartame
controversy
Saccharin
Sodium cyclamate
Sorbitol
Sucralose
Toxins, poisons, environment pollution
Aflatoxin
Arsenic contamination of groundwater
Benzene in soft drinks
Bisphenol A
Dieldrin
Diethylstilbestrol
Dioxin
Mycotoxins
Nonylphenol
Shellfish poisoning
Food processing
4-Hydroxynonenal
Acid-hydrolyzed vegetable protein
Acrylamide
Creutzfeldt–Jakob disease
Food additives
Food irradiation
Heterocyclic amines
Modified starch
Nitrosamines
Polycyclic aromatic hydrocarbon
Shortening
Trans fat
Water fluoridation controversy
Food contamination incidents
Devon colic
Swill milk scandal
Esing Bakery incident
1858 Bradford sweets poisoning
1900 English beer poisoning
Morinaga Milk arsenic poisoning incident
Minamata disease
1971 Iraq poison grain disaster
Toxic oil syndrome
1985 Austrian diethylene glycol wine scandal
United Kingdom BSE outbreak
Australian meat substitution scandal
1993 Jack in the Box E. coli outbreak
1996 Odwalla E. coli outbreak
2006 North American E. coli outbreaks
ICA meat repackaging controversy
2008 Canada listeriosis outbreak
2008 Chinese milk scandal
2008 Irish pork crisis
2008 United States salmonellosis outbreak
2011 Germany E. coli outbreak
2011 United States listeriosis outbreak
2013 Bihar school meal poisoning incident
2013 horse meat scandal
2015 Mozambique funeral beer poisoning
2017 Brazil Operation Weak Meat
2017–2018 South African listeriosis outbreak
2018 Australian rockmelon listeriosis outbreak
2018 Australian strawberry contamination
Food safety incidents in China
Food safety incidents in Taiwan
Foodborne illness
outbreaks
death toll
United States
Regulation, standards, watchdogs
Acceptable daily intake
E number
Food labeling regulations
Food libel laws
Food safety in Australia
International Food Safety Network
ISO 22000
Nutrition facts label
Organic certification
Quality Assurance International
United Kingdom food information regulations
Institutions
Centre for Food Safety (Hong Kong)
European Food Safety Authority
Food and Drug Administration
Food Information and Control Agency (Spain)
Food Standards Agency (United Kingdom)
Institute for Food Safety and Health
International Food Safety Network
Ministry of Food and Drug Safety (South Korea)
Spanish Agency for Food Safety and Nutrition
Related topics
Curing (food preservation)
Food and drink prohibitions
Food marketing
Food politics
Food preservation
Food quality
Genetically modified food
Conspiracy theories
Food portal Drink portal
Category
Commons
Cookbook
WikiProject
Authority control databases: National
France
BnF data
Germany
Israel
United States
Japan | biology | 92125 | https://da.wikipedia.org/wiki/Cyanobakterier | Cyanobakterier | Cyanobakterie, cyanobacteria, cyanophyta (Græsk: cyanos = blå) er en række af bakterier. De er almindeligvis kendt som blågrønalger, selvom de ikke er beslægtet med alger (som alle er eukaryote).
Cyanobakterier er autotrofe, og får deres energi gennem fotosyntese. De træffes som stromatolitter og menes at have spillet en vigtig rolle i jordens udvikling ved at være den organisme, der udviklede fotosyntesen for mindst 2,3 mia år, måske for så længe siden som 3,8 mia år, hvorved jordens oprindelige iltløse atmosfære blev iltholdig (se iltkatastrofen) og derved banede vejen for den lange række af organismer, der lever af ilt. Endvidere menes de ved endosymbiose at være ophavet til planternes og andre højere organismers grønkorn og er dermed grundlaget for al fotosyntese på jorden.
Visse cyanobakterier kan desuden udføre kvælstoffiksering, altså omdanne atmosfærisk kvælstof til organiske kvælstofforbindelser. Hermed er opblomstring af blågrønalger i et havområde medvirkende til, at Redfieldforholdet opretholdes i vandmiljøet, hvis det er underforsynet med kvælstof i forhold til fosfor.
Klassifikation
Cyanobakterier har tidligere været underlagt den botaniske systematik, mens de i dag hører under prokaryoternes systematik. Der offentliggøres dog stadig undersøgelser, som benytter botaniske betegnelser, hvad der skaber betydelige problemer i forståelsen af disse organismer. Efter 1.1. 1980 er organisationen International Committee on Systematics of Prokaryotes (ICSP) den, der samler og systematiserer viden om disse væsner.
Cyanobakterier i Danmark
Aphanizomenon og Nodularia spumigena er almindeligt forekommende cyanobakterier i Danmark.
Om sommeren forekommer cyanobakterier i Østersøen. Med østenvind spredes de til danske farvande og kan gøre badning risikabel.
Cyanotoxiner
Nogle cyanobakterier producerer toxiner kaldet cyanotoxiner, der kan være neurotoxiner, hepatotoxiner, cytotoxiner, endotoxiner eller carcinogener. Det er nogle af de stærkeste biologiske giftstoffer, der kan medføre en hurtig død på grund af åndedrætslammelse. Cyanotoxinerne omfatter bl.a. anatoxin-a (også kaldet Very Fast Death Factor), anatoxin-as, aplysiatoxin, cylindrospermopsin, Lyngbyatoxin-a, domoic acid, microcystin LR, nodularin R, neosaxitoxin, saxitonin eller STX, lipopolysaccharid og BMAA (β-Methylamino-L-alanine). Kemisk set er de meget forskellige: ringformede peptider, alkaloider og polyketider - lipopolysaccharid (LPS, også kaldet endotoxin) er i en gruppe for sig selv.
Det er specielt under opblomstring, at cyanobacterier kan blive en sundhedsrisiko for dyr og mennesker.
Cyanotoxinerne kan igennem fødekæden opkoncentreres i fisk og muslinger og medføre forgiftning:
DSP-toxin (efter Diarrhetic Shellfish Poisoning) medfører diaré
Saxitoxin, benævnt PSP-toxin (efter Paralytic Shellfish Poisoning) medfører dødelige lammelser
ASP-toxin (efter Amnesic Shellfish Poisoning) medfører skade på hjernecellerne og give varigt hukommelsestab
Se også
Død zone
Ciguatera, CFP efter Ciguatera Fish Poisoning
Prochlorococcus
Eksterne links
Blåmuslingeforgiftning. Sundhed.dk
Blågrønalger. Naturstyrelsen
Kilder/referencer
Gillian Cribbs (1997) Nature's Superfood, the Blue-Green Algae Revolution. Newleaf.
Cyanobacteria Are Far From Just Toledo’s Problem. the New York Times, august 2014
Marshall Savage, (1992, 1994) The Millennial Project: Colonizing the Galaxy in Eight Easy Steps. Little, Brown.
:wikispecies:Cyanobacteria
Nitrogenmetabolisme
Prækambrium | danish | 0.558969 |
mouldy_food_sick/.txt | * Latest
* U.S.
* World
* Politics
* Entertainment
* HealthWatch
* MoneyWatch
* Investigations
* Crime
* Space
* Sports
* Local News
* Baltimore
* Bay Area
* Boston
* Chicago
* Colorado
* Detroit
* Los Angeles
* Miami
* Minnesota
* New York
* Philadelphia
* Pittsburgh
* Sacramento
* Texas
* Live
* CBS News 24/7
* Baltimore
* Bay Area
* Boston
* Chicago
* Colorado
* Detroit
* Los Angeles
* Miami
* Minnesota
* New York
* Philadelphia
* Pittsburgh
* Sacramento
* Texas
* Shows
* 48 Hours
* 60 Minutes
* America Decides
* CBS Evening News
* CBS Mornings
* CBS News Eye on America
* CBS News Mornings
* CBS Reports
* CBS Saturday Morning
* The Daily Report
* The Dish
* Face the Nation
* Here Comes the Sun
* Person to Person
* Sunday Morning
* The Takeout
* The Uplift
* Weekender
* * CBS News Investigates
* Photos
* Podcasts
* In Depth
* Newsletters
* Download Our App
* CBS News Team
* Executive Team
* Paramount Shop
* Paramount+
* Join Our Talent Community
* RSS Feeds
* A Moment With...
* Innovators & Disruptors
* Los Angeles
* News
* All News
* LA News
* OC News
* IE News
* U.S.
* CBS2 Investigations
* Entertainment
* Politics
* Consumer
* Business
* Health
* On Your Side
* CBS+
* Weather
* Latest Weather
* Radars & Maps
* Sports
* All Sports
* Chargers
* LA Kings
* Rams
* Lakers
* Clippers
* Golf
* CBS Sports HQ
* Dodgers
* Angels
* Soccer
* Hockey
* College Sports
* Videos
* KCAL News Shows
* The Morning Wrap
* The Lot
* STEAM
* On Your Side: Veterans' Voices
* Inside SoCal
* Java with Jamie
* Investigation
* Class Act
* SoCal Spotlight
* People Making a Difference
* * Station Info
* KCAL News Team
* Contests & Promotions
* Advertise
* Seen on TV
* News Tip
* Download the App
* Galleries
Watch CBS News
Los Angeles
# USDA: Some Moldy Foods Are OK To Eat
June 16, 2011 / 10:07 AM PDT / KCAL News
* * *
LOS ANGELES (CBS)— Not all moldy foods need to be thrown away.
According to researchers at Health.com, mold found on meat products like hot
dogs and bacon is harmful. Bacteria, which invisible to the human eye, may be
growing alongside the mold. Foods that have high moisture content such as
casserole and yogurt should be tossed at the first sign of contamination.
Porous food such as bread and cakes should also be discarded.
But experts say throwing away moldy fruits and veggies is not necessary. Mold
has trouble penetrating into dense foods. As long as the fruit or vegetable is
firm, trim off a inch around the mold and feel free to munch away.
### More from CBS News
Nearly $80,000 worth of baby walkers, toys seized at Los Angeles County ports
Got old meds? Collection sites set up across Los Angeles on National Drug Take
Back Day
4 men seen running away from shots fired in Long Beach
Security guard injured in shooting outside Encino home
University of Arizona student from Newport Beach shot and killed at off-campus
party
First published on June 16, 2011 / 10:07 AM PDT
© 2011 CBS Broadcasting Inc. All Rights Reserved.
### Featured Local Savings
### More from CBS News
#### Nearly $80,000 worth of baby walkers, toys seized at Los Angeles County
ports
#### Got old meds? Collection sites set up across Los Angeles on National
Drug Take Back Day
#### 4 men seen running away from shots fired in Long Beach
#### Security guard injured in shooting outside Encino home
©2024 CBS Broadcasting Inc. All Rights Reserved.
* Terms of Use
* Privacy Policy
* California Notice
* Do Not Sell My Personal Information
* CBS 2
* Contests & Promotions
* Program Guide
* Sitemap
* About Us
* Advertise
* CBS Television Jobs
* Public File for KCBS-TV
* Public File for KCAL-TV
* Public Inspection File Help
* FCC Applications
* EEO Report
* facebook
* twitter
* instagram
* youtube
View CBS News In
CBS News App Open
Chrome Safari Continue
Be the first to know
Get browser notifications for breaking news, live events, and exclusive
reporting.
Not Now Turn On
| biology | 510190 | https://sv.wikipedia.org/wiki/Jung%20Brannen%20Associates | Jung Brannen Associates | TRO Jung/Brannen är den största internationella arkitektfirman.
Firman har bildats genom sammanslagninge av TRO (The Richie Organization) och Jung Brannen Associates 2006.
Verk i urval
Media 1 Tower, Dubai, Förenade Arabemiraten, 2007
World Trade Centre Residence i Dubai International Convention Centre, Dubai, Förenade Arabemiraten, 2007
The Residences at the Westin at The Westin, Providence, USA, 2007
Bostäder på Manchester Place, Manchester i New Hampshire, USA, 2005
The Grandview, Boston, 2004
One Lincoln Street, Boston, 2003
Ten Park Row, Providence, 2003
The Canyons Grand Hotel, Park City, USA, 1999
John Joseph Moakley United States Courthouse, Boston, 1998
Abu Dhabi Marine Operating Company Headquarters, Dubai, Förenade Arabemiraten, 1997
125 High Street Boston, 1991
222 Berkeley Street, Boston, 1991
145 High Street, Boston, 1991
Bank of America Tower, Saint Petersburg, USA, 1990
Alfred Condominiums, New York City 1987
One Exeter Plaza, Boston 1984
1615 L Street, Washington, USA, 1984
One Financial Center , Boston, 1983
One Post Office Square, Boston, 1981
Caggiano Plaza, Lynn, USA, 1976
511 Congress Street, Portland i delstaten Maine, USA, 1974
Ten Post Office Square, Boston
Wyndham Boston Hotel, Boston
Custom House Tower, Boston
Museum of Fine Arts, Boston Boston
One Citizens Plaza, Providence, Rhode Island, USA
Paris Landing State Park Conference Center, Paris, Tennessee, USA
Baptist Medical Arts Building, Miami, USA
Calvary Episcopal's educational, Memphis, Tennessee, USA
Central Station Intermodal Transportation Facility , Memphis, USA
Cordova High School
Cullman Baptist Regional Medical Center
Emergency Center South Shore Hospital South, Weymouth, Massachusetts
Ernst & Young, LLP - Office of Structured Finance, Memphis, USA
Harris Building, Birmingham, Alabama, USA
Harvard University School of Dental Medicine Faculty Practice Clinic, Cambridge, Massachusetts, USA
Lowell General Hospital Cancer Center Lowell
Morton Plant Mease Healthcare
New Hope Christian Academy, Memphis, Tennessee
Philippines Medical Center
RiverPlace Senior Living Facility, Florida
Saint Francis Hospital and Medical Center Hartford, Connecticut
Saint Francis Hospital Cancer Center Hartford, Connecticut
Saint Margaret’s Center for Women and Infants at Saint. Elizabeth’s Medical Center, Boston
Springhouse Continuing Care Retirement Community, Boston Massachusetts
SwedishAmerican Hospital Rockford, Illinois
University of Alabama Health Services Foundation (UAHSF)Administration Building, Birmingham, Alabama
University of Alabama’s Health Services Foundation - Kirklin Clinic, Birmingham, Alabama
University of Memphis Ned R. McWherter Library, Memphis, USA
Amerikanska arkitektfirmor | swedish | 0.641499 |
mouldy_food_sick/what-moldy-foods-is-it-ok-to-eat-2018-11.txt | Menu icon A vertical stack of three evenly spaced horizontal lines. Search
icon A magnifying glass. It indicates, "Click to perform a search".
Business Insider logo Business Insider logo
Newsletters
Subscribe
Account icon An icon in the shape of a person's head and shoulders. It often
indicates a user profile.
Log in
Subscribe
* Business
* Strategy
* Economy
* Finance
* Retail
* Advertising
* Careers
* Media
* Real Estate
* Small Business
* Tech
* Science
* AI
* Sustainability
* Enterprise
* Transportation
* Startups
* Innovation
* Markets
* Stocks
* Indices
* Commodities
* Crypto
* Currencies
* ETFs
* Lifestyle
* Entertainment
* Culture
* Travel
* Food
* Health
* Parenting
* Reviews
* Tech
* Streaming
* Home
* Kitchen
* Style
* Beauty
* Pets
* Gifts
* Deals
* Coupons
* About BI Coupons
* Today's Best
* Samsung
* Google Workspace
* Politics
* Military & Defense
* Law
* Education
* Personal Finance
* Banking
* Credit Cards
* Investing
* Loans
* Mortgages
* Video
* Big Business
* Food Wars
* So Expensive
* Explainers
* News
* Still Standing
* Boot Camp
* All
* A-Z
* Advertising
* AI
* Banking
* Business
* Careers
* Commodities
* Coupons
* Credit Cards
* Crypto
* Culture
* Currencies
* Economy
* Education
* Enterprise
* Entertainment
* ETFs
* Finance
* Food
* Health
* Indices
* Innovation
* Investing
* Law
* Lifestyle
* Loans
* Markets
* Media
* Military & Defense
* Mortgages
* Parenting
* Personal Finance
* Politics
* Retail
* Reviews
* Small Business
* Science
* Startups
* Stocks
* Strategy
* Sustainability
* Tech
* Transportation
* Travel
* Video
* Featured
* Talent Insider
* About
* About
* Advertise
* Careers
* Code of Ethics
* Contact Us
* Corporate
* Corrections Policy
* Follow
* RSS
* Sitemap
* Facebook
* Twitter
* Instagram
* YouTube
* LinkedIn
* Subscriptions
* Intelligence
Close icon Two crossed lines that form an 'X'. It indicates a way to close an
interaction, or dismiss a notification.
Chevron icon It indicates an expandable section or menu, or sometimes
previous / next navigation options. Homepage
Newsletters
Account icon An icon in the shape of a person's head and shoulders. It often
indicates a user profile.
Log in
Subscribe
News
# 4 foods it's OK to eat moldy, and 6 it's definitely not
Ann Schmidt
2018-11-07T20:49:17Z
Share icon An curved arrow pointing right. Share
Facebook Icon The letter F. Facebook Email icon An envelope. It indicates
the ability to send an email. Email Twitter icon A stylized bird with an
open mouth, tweeting. Twitter LinkedIn icon LinkedIn Link icon An image
of a chain link. It symobilizes a website link url. Copy Link
Save Article Icon A bookmark Save
Read in app
Angle down icon An icon in the shape of an angle pointing down. If you
notice mold on your bread — toss it. DmyTo/iStock
This story is available exclusively to Business Insider subscribers. Become
an Insider and start reading now. Have an account? Log in .
It happens to everyone: you go into your cabinet and pull out a loaf of bread
to find a green fuzzy spot on one of the slices. You'll probably do one of two
things. Either you cut off the moldy part and eat it anyway or just throw it
out.
Advertisement
According to the USDA , mold can cause allergic reactions or respiratory
problems and certain kinds of molds produce poisonous mycotoxins that make
people sick or cause infections. Invisible bacteria can also grow alongside
mold, which makes it even more dangerous to consume.
This story is available exclusively to Business Insider subscribers. Become
an Insider and start reading now. Have an account? Log in .
Even though you should definitely toss your moldy bread in the trash , there
are a four types of foods you can still eat as long as you cut off the mold,
according to the USDA Food Safety and Inspection Service .
But be careful, the USDA also keeps a list of other foods you should always
throw away if you spot mold.
Advertisement
## Hard salami and dry-cured country hams are OK to eat if they seem a bit
moldy.
The mold actually protects the salami. Flickr/Kent Wang
The white coating around certain hard salamis is actually a dusting of a
benign mold which helps cure the salami and preserve it from bacteria.
It is also normal for dry-cured hams to develop some surface molds. As long as
you scrub the mold off your cured ham, it is safe to eat .
## Firm fruits and vegetables with low moisture such as carrots, cabbage, and
bell peppers can handle a little bit of mold.
Just cut off the mold. Flickr/U.S. Department of Agriculture
Molds have a harder time growing roots in dense foods, so if you cut off at
least 1 inch around the spot of mold, you should be fine to eat your firm
fruits and vegetables. Just make sure to keep the knife out of the mold to
avoid cross-contaminating your produce.
Advertisement
## You can eat hard cheeses made without mold such as cheddar cheese.
Again, be sure to cut off the moldy part of the cheese. Flickr/Brian
Boucheron
As long as you cut off at least 1 inch around the moldy spot and re-cover the
cheese in a clean wrapping, your hard cheeses should be safe to eat .
Advertisement
## Certain cheeses made with mold, such as Gorgonzola, are OK to eat, even if
you notice mold.
Still, keep a lookout for molds not used to make the cheese. Sydney Kramer
Obviously, there are a lot of cheeses that are made with mold, including
Roquefort, blue, Gorgonzola, Stilton, Brie and Camembert. You have to be
careful , however, when they develop other kinds of mold not used in the
manufacturing process.
If your softer cheeses like Brie or Camembert grow mold, you should throw them
away. For harder cheeses like Gorgonzola or Stilton, you can cut off at least
1 inch around the moldy spot and keep eating it.
Advertisement
## Bread and baked goods with mold can be dangerous.
A black mold is especially dangerous. Flickr/Manchester Metropolitan
University
It is easy for mold to grow and contaminate soft and porous foods like bread
and baked goods. One common mold that grows on bread, Rhizopus stolonifer ,
also called black bread mold, can cause deadly infections. Instead of risking
sickness, baked goods with mold should all be thrown away.
## Soft fruits and vegetables such as cucumbers, peaches, and tomatoes are a
no-go if they have mold.
It's best to avoid peaches if they look moldy. gdmoonkiller / iStock
Fruits and vegetables with high moisture content are more easily contaminated
by mold below the surface and should just be tossed in the trash.
Advertisement
## Soft cheeses and crumbled, shredded, and sliced cheeses are best avoided.
Cottage cheese should be thrown out if you notice mold. Wikimedia Commons
Soft cheeses including cottage cheese, cream cheese, Neufchatel, chevre, and
Bel Paese should be thrown away if you find mold because the high moisture
content makes it easier for the cheese to be contaminated below the surface
and there is a likelihood of bacteria growing along with the mold.
Cheeses that are crumbled, shredded or sliced and have mold on them should
also be thrown away because it is possible they were contaminated by the
cutting instrument.
## Peanut butter, legumes, and nuts are at risk for dangerous molds.
It has to do with a lack of preservatives in the food. Photo-Dave/ iStock
Foods that are made without preservatives, like nuts and legumes, have a
higher risk of developing mold and those molds are more likely to produce
dangerous toxins .
Advertisement
## Jams and jellies should be tossed.
They might produce a dangerous mold. Pixabay
The mold that grows in jams or jellies could be producing a mycotoxin, so even
if you scooped out the mold, you're still at risk of consuming poisonous
toxins. Instead, you should just throw out your moldy jams.
Advertisement
## Any food with high moisture content should probably be discarded.
Yogurt's high moisture content makes it at-risk for developing mold. Caroline
Praderio/INSIDER
It is easy for mold to grow below the surface of foods with high moisture
content. Those foods are also at higher risk of invisible bacteria growing
alongside the mold, which makes it even more dangerous to eat.
The USDA recommends throwing away any of these high-moisture-content foods
if you find mold: lunch meats, bacon, hot dogs, cooked leftover meat and
poultry, cooked casseroles, cooked grain, cooked pasta, yogurt, and sour
cream.
Visit INSIDER's homepage for more.
Read the original article on INSIDER . Copyright 2018.
Follow INSIDER on Facebook .
Follow INSIDER on Twitter .
Read next
NEW LOOK
Sign up to get the inside scoop on today’s biggest stories in markets, tech,
and business — delivered daily. Read preview
Thanks for signing up!
Access your favorite topics in a personalized feed while you're on the go.
download the app
Email address
Sign up
By clicking “Sign Up”, you accept our Terms of Service and Privacy Policy
. You can opt-out at any time.
Advertisement
Close icon Two crossed lines that form an 'X'. It indicates a way to close an
interaction, or dismiss a notification.
Advertisement
Recommended video
Advertisement
Follow us on:
* * Copyright © 2024 Insider Inc. All rights reserved. Registration on or use of this site constitutes acceptance of our Terms of Service and Privacy Policy .
* Contact Us
* Masthead
* Sitemap
* Disclaimer
* Accessibility
* Commerce Policy
* Advertising Policies
* Coupons
* Jobs @ Business Insider
* Stock quotes by finanzen.net
* Reprints & Permissions
Your Privacy Choices
* International Editions:
* United States US
* International INTL
* Deutschland & Österreich AT
* Deutschland DE
* España ES
* India IN
* Japan JP
* México MX
* Netherlands NL
* Polska PL
Jump to
1. Main content
2. Search
3. Account
| biology | 319655 | https://no.wikipedia.org/wiki/Bolus | Bolus | Bolus er en liten rund klump som består av en blanding av mat og spytt som er formet av tungen og tennene. Den har form og konsistens som gjør den lett å svelge, noe som også er hele hensikten.
Fordøyelsessystemet | norwegian_bokmål | 1.218052 |
mouldy_food_sick/nutrition-expert-mouldy-food-edible-list.html.txt | * Home
* News
* Royals
* U.S.
* Sport
* Showbiz
* Femail
* Health
* Science
* Money
* Travel
* Podcasts
* Shopping
* Best Buys
* My Profile
* Logout
* Login
* Discounts
* TUI
* Booking.com
* ASOS
* Just Eat
* Deliveroo
* boohoo
* Very
* Nike
* Virgin Media
* Uber Eats
* Boots
* B&Q
* Amazon
* John Lewis
* My Profile
* Logout
* Login
* My Profile
* Logout
* Login
Privacy Policy Feedback
Tuesday, Apr 30th 2024 2PM 28°C 5PM 25°C 5-Day Forecast
Advertisement
# I'm a food safety expert and here's a what you CAN still eat even if it's
mouldy
* Eating mould on nuts, grains and apples could cause liver damage, experts warn
* Cutting off the mouldy section of hard cheese can be safe, but not soft cheese
By Rebecca Whittaker For Mailonline
Published: 08:14 BST, 10 December 2023 | Updated: 10:40 BST, 10 December 2023
* * * * * * e-mail
*
456 shares
1k
View
comments
It can be disappointing to find your loaf of fresh bread (well, you thought it
was, anyway) covered in patches of green mould.
But did you know, with some foods, it can be harmless to scrape off the mouldy
patches and tuck in?
Just don't try doing it with bread...
That's according to food safety specialist Dr Richard Fuchs, of the University
of Greenwich, who tells MailOnline what food can you still eat, even when
mouldy, and what should be going straight in the bin.
Because bread is porous, mould structures are able to grow throughout it and
not just on the surface
Food that is obviously rotting or contains mould should not be eaten,
according to the Food Standards Agency (FSA).
This advice is especially important for people in vulnerable groups, such as
children, people who are pregnant, those aged over 65 and anyone with a
weakened immune system.
Consuming mould — technically just a microscopic fungus — can make us sick.
## Avoid mouldy grains, nuts and apples
Nuts, grains and apples can be some of the most dangerous food to eat, that is
if you find a patch of mould on them, according to Dr Fuchs.
He said: 'Consumers may be allergic to the moulds or develop respiratory
conditions if exposed.
'Secondly, moulds can produce toxic compounds called mycotoxins.'
Mycotoxins, described as 'extremely dangerous', can suppress the immune system
and trigger reproductive problems.
Some have even been linked to cancer.
'They will rarely have acute effects but they can over a long period of
exposure,' according to Dr Fuchs.
Soft fruits and vegetable, like tomatoes (pictured), are less resistant to
mould than a harder fruit or vegetable such as a carrot
However, aflatoxin, the most harmful type of mycotoxin, is known to cause
these severe complications.
It is produced by two species of mould — Aspergillus flavus and Aspergillus
parasiticus — and may be found in mouldy nuts, rice, spices, vegetable oils
and cocoa beans.
In large doses, aflatoxins can be life-threatening.
Patulin is another mycotoxin that can grow on rotting apples. If eaten it can
cause 'nausea, gastrointestinal disturbances and vomiting', according to the
World Health Organization.
## Avoid mouldy soft cheese, berries and bread
While not all mould is this dangerous, it can still make you feel unwell if
eaten.
To make matters trickier, the mould you can see on the surface of food isn't
the full extent of the problem, warns Dr Fuchs.
By this point, mould spores have already deeply invaded the product.
'Moulds produce microscopic thread like structures called hyphae which can
spread into the food,' he said.
'Therefore, what is visible on the surface may not be the full extent of the
contamination by the mould.'
The softer the food, the easier it is for mould to penetrate its surface.
Removing the mould from a block of hard cheese and 2.5cm around it can make it
safe to eat. Blue cheese (pictured), is made with mould that is safe to eat
For example, food with a high water content, such as juicy berries, jam or
even soft cheese encourages the mould to spread deeper.
Bread is another culprit, with its porous structure allowing hyphae to grow
into it.
That means when you find a small patch of mould, it's likely to be in the
whole of the jar of jam or punnet of fruit, even if it is only visible on the
surface.
## But some cheeses ARE safe
One of the only foods you can eat even if it is mouldy is hard cheese.
'Hard, dense foods like hard cheeses or firm fruits and vegetables are more
resistant to penetration by the mould so the mould could be cut out and the
food consumed', he added.
To be safe Dr Fuchs recommends people cut off about 2.5cm of food around and
below the mouldy area.
However, when mould is specifically used to make a product, such as blue
cheese, it is safe to eat.
### Share or comment on this article: I'm a food safety expert and here's a
what you CAN still eat even if it's mouldy
* * * * * * e-mail
* * 456
shares
### Comments 1027
Share what you think
* Newest
* Oldest
* Best rated
* Worst rated
View all
The comments below have not been moderated.
View all
The views expressed in the contents above are those of our users and do not
necessarily reflect the views of MailOnline.
We are no longer accepting comments on this article.
Bing
Site Web Enter search term: Search
Advertisement
### DON'T MISS
* Barbra Streisand grills Melissa McCarthy about Ozempic use in Instagram comments section leaving fans GOBSMACKED
* Kim Kardashian the copycat! Reality star looks just like Kanye West's new wife Bianca Censori with bleached hair, no bra and skimpy 'apron' top
* Britney Spears needs a new conservatorship and heavy medication according to Hollywood psychiatrist... after singer deletes her Instagram
* This Morning's Michelle Elman shares emotional update after revealing she split with her fiance after discovering he was cheating
* Doctor Who star Millie Gibson address her future on the show as she breaks her silence on rumours that she was axed after just one series
* Sip your way into being summer ready! The tips and tricks to looking your best as temperatures rise (including one you can DRINK!) Ad Feature
* Rhod Gilbert shares cancer update as he admits he's 'pinching himself' over performing stand-up again two years after diagnosis
* Jennifer Garner looks very much in love with boyfriend of 6 years John Miller as they make the rare move of holding hands in Los Angeles
* Anne Hathaway is a vision in red strapless gown with daring bodice and thigh-high slit as she leads the stars at New York City premiere of The Idea of You
* Summer sun and family fun: The very best last-minute holiday deals for families, with hotels and villas to suit EVERYONE Ad Feature
* The King will return to public duties today after 'pleasing' doctors with his cancer treatment: Charles and Camilla will visit specialist cancer centre
* Dua Lipa and boyfriend Callum Turner put on a loved-up display as they hold hands during a date night in New York City
* Jessica Chastain, Jodie Turner-Smith and Kerry Washington light up the red carpet in plunging ensembles at Ralph Lauren Fall/Holiday 2024 fashion show in NYC
* Glenn Close, 77, stuns in white at the Ralph Lauren Fall/Holiday 2024 fashion show in New York... revealing on Instagram it's the same suit from 2019 SAG Awards five years ago
* Ready, set, renew! Top 10 health hacks to help you revitalise your routine for the vibrant season ahead Ad Feature
* Inside Garden Rescue host Charlie Dimmock's affair with co-star which she insists she has 'no regrets' about The green fingered star is back on TV screens
* Kim Kardashian's company SKIMS now accidentally reveals her bra size is a SMALL even though she's always busty at events Admission
* EastEnders actress Cheryl Fergison reveals she SCALDED herself with boiling water as she became obsessed with 'washing' away cancer cells
* Lorraine Kelly looks radiant as pregnant daughter Rosie Smith displays her growing baby bump at the Golden Chopsticks Awards
* Don't suffer in silence: From painful periods to brain fog, women often suffer from menstrual or menopause issues, but help is at hand... Ad Feature
* Jennifer Connelly shows off her toned legs in a tiny white mini skirt as she cuddles up to co-star Joel Edgerton at the LA premiere for their new Apple+ show Dark Matter
* Coleen Rooney gives a glimpse into her £20million mansion as she employs a celebrity-approved cleaning service to transform carpets
* Junior Andre's 'secret girlfriend revealed' - who has already appeared on television and dated a very well known reality star All the details
* Gwyneth Paltrow and husband Brad Falchuk put on an affectionate display as they wrap their arms around each other after dinner date in LA
* Idyllic beach breaks: Discover the best of the Mediterranean with this month's top hotel picks... from an Algarve beauty to a Turkish hideaway Ad Feature
* Emily Blunt keeps it chic in black Louis Vuitton turtleneck as she waves at fans while arriving at Jimmy Kimmel Live in Hollywood to promote The Fall Guy
* Rebel Wilson looks glamorous in black dress with mesh detail after Sacha Baron Cohen broke his silence on her redacted memoir's UK release
* Cynthia Erivo dazzles in a striking black and white dress as she poses on the red carpet at the 49th Chaplin Awards ceremony in New York City
* EDEN CONFIDENTIAL: Prince Harry's army friend JJ Chalmers urges Kate to talk about cancer Doing his bit to help mend fences
* Gabrielle Union wows in a black sleeveless gown at The Idea of You premiere in New York
* Brave Sophie becomes the first British royal to visit Ukraine since the start of the war: Duchess of Edinburgh meets President Zelensky
* Julie Andrews, 88, is seen for the first time in seven months as she makes rare public appearance on shopping trip in The Hamptons
* Meghan WON'T join Prince Harry in Britain for Invictus Games anniversary service, Sussex spokesman confirms Not coming
* Sharon Stone, 66, flaunts age-defying figure in a glowing black sequined dress as she leads the stars honoring Jeff Bridges, 74, at 49th Chaplin Award Gala in New York City
* Target fine lines and dark circles! Beauty fans 'more youthful' after using this £40 eye cream: 'Visible reduction in under-eye bags' SHOPPING
* Chris Pine dons plaid blazer to honor his hero Jeff Bridges at 49th Chaplin Award Gala in NYC Pine starred with Bridges in the film Hell or High Water
* Ella Beatty, youngest daughter of Warren Beatty and Annette Bening, is a vision in white at 49th Chaplin Award Gala honoring Jeff Bridges
* Sarah Paulson rocks blue blouse and black trousers as she attends the 49th Chaplin Award Gala in NYC with her Appropriate co-star Ella Beatty
* Duchess of Edinburgh shares heartwarming moment with toddler as she visits UNFPA office in Kyiv during tour of Ukraine
* Liz Hurley opens up about the terrible toll Shane Warne's death took on her - and the cricket icon's ties to her son Damian Tragic loss
* Denise Welch confirms she's moved house after knife-wielding stalker received seven year jail sentence for starting a fire at the property
* Love Island star 'splits from boyfriend' two years after moving in together as fans spot they have 'removed all traces of each other from social media'
* Sir Mick Jagger makes heartbreaking confession about performing without the Rolling Stones' late drummer Charlie Watts band embarks on tour
* Amanda Holden and Alan Carr's Tuscan house 'is sold for a staggering sum' after pair teamed up to restore the 17th century property for BBC show
* REVEALED: The SPF mist users hail a 'sun saviour' that shields your skin without ruining your makeup (and we have an exclusive discount code) SHOPPING
* Strictly star Nadiya Bychkova reveals a VERY senior royal 'who is huge fan of the show' has told her they would love 'to be a contestant'
* Duchess of Edinburgh is elegant in £1,250 Etro dress as she becomes first British royal to visit Ukraine Flew into the war-torn country on Monday
* Khloe Kardashian showcases her fit form in black bikini... as sister Kylie Jenner calls her a 'cutie'
* Chris Hemsworth flexes muscular form as sword-wielding Barbarian filming Clash of Clans commercial in LA with Christina Ricci, Ken Jeong, and more
* Succession star Brian Cox says his 'favorite line of the whole show' is when Logan Roy 'says to the kids "I love you, but you're not serious people"'
* Dakota Johnson gets back to work after her Madame Web box office disaster as she films with Pedro Pascal on set of the Materialists in New York
* Sheer delight! Anya Taylor-Joy looks chic in a mesh top and grey trousers as she touches down in Sydney ahead of Furiosa: A Mad Max Saga premiere
* Gemma Atkinson and Gorka Marquez 'are planning to buy a family home in Spain' to spend more time with the professional dancer's family
* Timothee Chalamet steps into 1960s NYC as he continues filming Bob Dylan biopic A Complete Unknown with director James Mangold
* Model Paul Sculfor details what it was like dating Cameron Diaz and Jennifer Aniston in his heyday - and reveals he is 'living a great, sober life'
* Jonathan Majors looks somber as he steps out with girlfriend Meagan Good for the first time after being sentenced in domestic violence case
* Mark Wahlberg can't believe his teen sons are 'taller than me already' as Michael, 18, and Brendan, 15, tower over him in rare family photo from Hawaii
* EXCLUSIVE Inside Margot Robbie's friendship with BFF: How Barbie girl returned to her native Australia to be bridesmaid for her lifelong pal
* Selling the OC's Alex Hall divides fans by flaunting her derriere in cheeky chaps and a thong at Stagecoach festival: 'Not classy!' Questionable
* Blackadder could be made into an 'original play' but writer Ben Elton fears the iconic TV show's legacy would be damaged if stage show failed
* Garden Rescue star Charlie Dimmock's dramatic transformation over the years as unearthed photos show her TV debut alongside Alan Titchmarsh
* Naomi Watts shows off rings worth a whopping $54K... after paying tribute to pal Nicole Kidman for her AFI Life Achievement Award
* Zendaya covers the debut issue of her Challengers magazine as she launches Instagram for movie character Tashi Duncan: 'An honor'
* George Clooney's new TV project is revealed as Hollywood legend prepares to start shooting with Michael Fassbender this summer
* Succession star Brian Cox says 'the Bible is one of the worst books ever' as he condemns impact of religion on the world: 'People are so stupid'
* Brave Sophie denounces Putin's forces for using rape as a weapon of war: Duchess of Edinburgh rails against 'degrading' sexual violence
* Queen Camilla tells sailor to 'put back' a glass of champagne as royal hosts reception for first female crew to win around-the-world yacht race
* Taylor Armstrong admits she's dreading her daughter Kennedy, 18, leaving home for college: 'It's a little hard, she's my only child'
* Miriam: Death Of A Reality Star review - TV show treated trans woman as the punchline in an obscene joke, writes CHRISTOPHER STEVENS
* Zack Norman dead at 83: Romancing The Stone star who played crocodile- loving smuggler in iconic 1984 film passes away
* Rita Ora stuns in a nude strapless bustier and floor-length trousers with sheer gloves as she launch her new haircare brand TYPEBEA
* Would you want Barbie as your bridesmaid? Margot Robbie celebrates her best friend's wedding in her native Queensland
* Jerry Seinfeld sparks fears for his health after fans spot worrying detail in his interview with Graham Bensinger Made an appearance on In Depth
* Inside Layton Williams' getaway: Strictly star enjoys £350-a-night stay in Jamaica with stunning room and choice of nine restaurants
* EXCLUSIVE Reclusive Connie Booth will 'sneak in' to watch the Fawlty Towers stage show when it launches in the West End Looking forward to it
* Rihanna hilariously reveals the perks of being a boy mom: 'I get to be as casual and busted as I want to' Discussed the benefits at a Fenty event
* EXCLUSIVE General Hospital star Haley Pullos, 25, is slapped with three months in jail after pleading no contest to DUI crash Behind bars
* This Morning star breaks down in tears as she reveals she has split from her fiancé after finding out he was cheating on her the day he proposed
* BBC Antiques Roadshow expert refuses to value WWII painting due to links to German concentration camp as guest shares its backstory
* Strictly Come Dancing's Layton Williams says partnership with Nikita Kuzmin may come to an end as they prepare to head on tour together
* Billie Eilish announces return to Australia in 2025 for upcoming world tour - here's how you can get tickets Back on the road
* Queen Mathilde of Belgium is elegant in floral dress as she attends 50th anniversary of the Baillet Latour foundation in Brussels
* Jenna Dewan showcases her baby bump on International Dance Day... amid court battle over Magic Mike proceeds with ex Channing Tatum
* Avengers directors Anthony and Joe Russo claim Marvel's recent failures are because of 'a big generational divide about how you consume media'
* Daniel Day-Lewis celebrates his 67th birthday with rare outing in NYC - after his My Left Foot director gave update on his acting retirement
* Jeff Bridges, 73, returning for Tron: Ares nearly 42 YEARS after original classic - as he jokes he 'looked more like Bill Maher' than himself in sequel
* Justin Bieber fans fear singer's social media crying selfies meltdown is linked to his childhood friendship with scandal-hit US rapper P-Diddy
* EXCLUSIVE Jeff Bezos' fiancée Lauren Sanchez sent cease and desist from former yoga teacher for allegedly COPYING her children's book
* I'm A Celeb star Snoochie Shy shows off her pert bottom in a tiny zebra print bikini as she lets her hair down during sunkissed Ibiza getaway
* Emily Ratajkowski models New York Rangers sweater following the team's first-round series sweep of the Washington Capital
* French screen legend Gerard Depardieu will go on trial for sexual assault in October - after actor was quizzed by police over claims Facing charges
* Love Island's Kai Fagan and Sanam Harrinanan are engaged: Couple share pictures from the big proposal - just 13 months after they won
* Eddie Murphy's The Pickup set crash victims suffered back and skull fractures when two stunt vehicles rolled off the road in horror crash Awful
* Jessica Alba turns 43! The Sin City actress poses with her mini-me daughters Honor and Haven: 'Feeling incredibly blessed' Special day
* Irina Shayk, 38, strips down to lacy black lingerie for VERY sultry selfie... amid claims she wants to date Tom Cruise, 61 Top bum
* Millie Bobby Brown shows off sensational figure in a purple bikini and green shorts as she films herself getting 'pool ready' at her lavish home
* Kristin Cavallari, 37, smooches boyfriend Mark Estes, 24, at Stagecoach as Laguna Beach vet shares loved-up moments from the country festival
* Coronation Street love rat looks vastly different from his days on the cobbles as he reveals cropped white hair during rare TV appearance
* Hopes for a Charles and Harry reunion? King and Duke of Sussex will both be in London at same time next week Separate duties
* Russell Brand reveals he's been baptised in the Thames as he turns to Christianity after rape and sex assault allegations Embracing a new faith
* Made In Chelsea's Victoria Baker Harber MARRIES Inigo Philbrick two months after he's released from prison following £80m art fraud
* The Weeknd's manager's security guard in 'critical condition' after he was shot during attempted invasion outside home
* Martin Freeman breaks silence on fierce backlash surrounding THAT X-rated scene between him and Jenna Ortega in their controversial movie
* EXCLUSIVE Helen Flanagan's ex-Scott Sinclair's mystery woman revealed as swimwear model who's known the Corrie star for NINE years
* Vicky McClure cuts a stylish figure in a red velvet suit as she and co-star Tom Cullen lead the arrivals at screening for her new series Insomnia
* American Idol star will Moseley divides fans after posting hunting video showing four dogs attacking a wild hog Not happy
* Katie Price, 45, flashes her surgically-enhanced assets in a bikini on holiday with boyfriend JJ Slater, 31, 'after skipping bankruptcy hearing'
* Charlie Dimmock returns to screens for a new series of Garden Rescue as she helps transform a tiny outdoor space into an exotic Balinese oasis
* Lady Gaga, 38, displays her toned legs in a short skirt after enjoying a tennis game with boyfriend Michael Polansky, 46, in Malibu
* Noah Cyrus keeps it casual in wintry pajamas - as she is seen for the first time since slamming troll who confronted her over family feud
* Kendall Jenner puts on a cheeky display in flesh-toned leggings while enjoying the Stagecoach music festival with friends Looking good
* Tim Allen looks ready to hit the links alongside Mötley Crüe rocker Tommy Lee and son Brandon for George Lopez golf charity event in LA
* Anne Hathaway showcases toned torso in sheer blue dress after looking chic in white mini dress on promotional run in NYC Looking good
* Morgan Freeman recreates Nicole Kidman's famous AMC ad in hilarious tribute at AFI Life Achievement Award event Comical
* Taylor Swift takes the Billboard Hot 100! Star claims record 14 SPOTS with The Tortured Poets Department tracks (including one chart-topper)
* Emily Ratajkowski bares her enviable abs in a white crop top and flirty green skirt while stepping out in NYC Top of the crops
* Richard Madeley says ITV international affairs correspondent Rageh Omaar will be back on screens 'soon' as he tells viewers 'he's making a good recovery'
* Scott Disick sports sunglasses at night and bundles up in baggy clothes after vowing to 'stop taking Ozempic' amid concerns from ex Kourtney Kardashian
* Peter Andre and wife Emily STILL haven't chosen a name for their baby nearly a MONTH since they welcomed their newborn daughter
* TOWIE wrap party is 'thrown into CHAOS as long-time cast member is locked in angry spat with co-star'
* Craig David delights fans as he announces huge new UK tour in 2025 with special guest Lemar: 'Noughties us is here for it!' Back on the road
* Kate Upton and Candice Swanepoel show off their supermodel physiques and flexibility while hanging off exercise rings on the beach
* Rachel McAdams channels Trinity from The Matrix in edgy leather dress and slick black shades as she steps out in NYC amid Broadway debut
* EXCLUSIVE Harvey Weinstein's $300million net worth plummets to $25million since his 2017 downfall - and is set to dwindle further as he heads for retrial
* Alice Evans, 55, claims she's failed to find love on celeb dating app Raya because famous men just want 'younger women'
* EXCLUSIVE Jesse Lally steps out with stunning new girlfriend Lacy Nicole - just days after estranged wife Michelle was accused of having a 'secret boyfriend'
* Pregnant Lea Michele displays her baby bump in a black bikini and beach skirt as she poses for Instagram snaps during Florida getaway
* Kim Zolciak and ex Kroy are on the brink of LOSING their $4.5M home to foreclosure... after lowering the price from $6M with still no takers
* X Factor's Sam Bailey reveals struggles to get her autistic son into a special school after he became suicidal due to lack of support in mainstream education
* Who furious Caitlyn Jenner flipped off... Chris Pine's humiliating snub... and Lynda Carter's flirting: The unseen secrets of the White House Dinner .
* Penélope Cruz marks her 50th birthday in star-studded style as she parties with Irina Shayk, husband Javier Bardem and Riccardo Tisci
* Ryan Gosling swaps places with This Morning's Alison Hammond as they reunite after THAT chaotic viral Blade Runner interview
* Busty Helen Flanagan displays her taut abs in a leopard print bikini as she strikes a pose for sexy Instagram snaps The Coronation Street star, 33, wowed
* THE SIDEBAR - Episode Richard Arnold is joined by Anna Whitehouse and Rezzy Ghadjar for another jam-packed show
* Eric Church DOUBLES DOWN on Stagecoach gospel headlining set -which was branded 'disappointing' and led festivalgoers to leave
* Dax Shepard shares hilarious video of Kristen Bell on nitrous at dermatologist appointment: 'Oh my God, she's so gassed' Funny
* Pregnant Briony Aston is treated to an ancient 'Red Thread Ceremony' in place of a baby shower to prepare for the birth of her third child
* Parks and Recreation star Amy Poehler announces she'll visit Australia for Sydney's Vivid festival ahead of new movie Inside Out 2 Getting involved
* Kate and William share unseen wedding portrait: Prince and Princess of Wales release stunning picture to mark their 13th wedding anniversary
Advertisement
* Follow DailyMail
* Subscribe Daily Mail
* Follow @dailymail
* Follow DailyMail
* Follow MailOnline
* Follow Daily Mail
* Back to top
* Home
* News
* Royals
* U.S.
* Sport
* Showbiz
* Femail
* Health
* Science
* Money
* Travel
* Podcasts
* Shopping
* Discounts
Sitemap Archive Video Archive Authors Topics Index Mobile Apps
Screensaver RSS Text-based site Reader Prints Our Papers Top of page
Daily Mail Mail on Sunday This is Money
Metro Newzit Mail Travel Discount Codes - about us Discount Codes FAQ
Published by Associated Newspapers Ltd
Part of the Daily Mail, The Mail on Sunday & Metro Media Group
dmg media Contact us How to complain Leadership Team Advertise with us
Contributors Terms Subscription Terms & Conditions Do not sell or share my
personal information About MailOnline Cookie Settings Privacy policy &
cookies
Advertisement
Advertisement
| |
---|---|---
| |
| |
| biology | 796906 | https://da.wikipedia.org/wiki/What%20the%20World%20Needs%20Now%20%28Glee%29 | What the World Needs Now (Glee) | What the World Needs Now er den sjette episode af den sjette sæson af den amerikanske musikalske tv-serie Glee , og den 114. overordnede set. Episoden blev skrevet af Michael Hitchcock, instrueret af Barbara Brown, og første gang sendt den 6. februar 2015 på Fox i USA.
Episoden handler om, at Mercedes Jones vender tilbage til McKinley High, for at hjælpe Rachel Berry med New Directions, og samtidig overbevise hende om, at forsøge at vende tilbage til New York for at være på Broadway. I mellemtiden, forbereder Santana Lopez og Brittany Pierce deres bryllup. Brittany forsøger at reparere forholdet mellem Santana og hendes bedstemor.
Plot
Sam Evans (Chord Overstreet) og Rachel Berry (Lea Michele) har nogle akavet møder, da de indser, at de er begyndt at have følelser for hinanden på grundlag af deres tidligere møder, men Sam har også stadig følelser for sin tidligere kæreste Mercedes Jones (Amber Riley). I mellemtiden, diskuterer Brittany Pierce (Heather Morris) hendes bryllup med Santana Lopez (Naya Rivera) med sine forældre Pierce (Ken Jeong) og Whitney (Jennifer Coolidge). De afslører overfor hende, at Brittanys rigtige far er Stephen Hawking, hvilket forklarer hendes ekstreme intelligens. Rachel og Kurt Hummel (Chris Colfer) giver New Directions-medlemmerne Kitty Wilde (Becca Tobin), Spencer Porter (Marshall Williams), Jane Hayward (Samantha Marie Ware), Roderick (Noah Guthrie), Mason McCarthy (Billy Lewis Jr.) og Madison McCarthy (Laura Dreyfuss) (med følgeskab af de tidligere kormedlemmer, Santana, og Artie Abrams (Kevin McHale)) deres opgave, som er at synge sange komponeret af Burt Bacharach, og de har brugt Mercedes' hjælp. Mercedes forsøger også at overbevise Rachel om, at hun skal fortsætte sit forhold til Sam, hvor Mercedes samtidig informere hende om en audition til en ny forestilling i New York. Men Rachel er stadig bange på grund af hendes tidligere fiaskoer, og er ikke sikker på, hun vil til audition. Mercedes spørger de mandlige medlemmer af New Directions sammen med Blaine Anderson (Darren Criss) om at hjælpe hende med, at overbevise Rachel.
Brittany beder Artie om, at være hendes bryllupsplanlægger og han accepterer, da de er enige om et tema som er "himlen". Da Brittany og Santana gennem går en invitationliste til brylluppet, er Santana tøvende over at invitere hendes bedstemor, Alma (Ivonne Coll), fordi Alma har underkendt Santana lige siden hun sprang ud, som lesbisk/biseksuel (som set i episoden "I Kissed a Girl"). Brittany fungerer som sygeplejerske for Alma og begynder at opbygge et venskab med hende, fortæller hende, at hun er forlovet, men fortæller ikke hvem hendes forlovede er.
Brittany får Alma til at blive vist på hendes webcastshow og oplyser, hvor vigtigt det er at have familie med til et bryllup. Sam fortæller Mercedes at han stadig har følelser for hende, men Mercedes fortæller ham, at de kun skal være venner, og at han skulle forfølge Rachel. Rachel beslutter sig endelig for at tage til New York, for at tage til audition. Brittany indbyder Alma til at deltage i en performance, hvor hun afslører, at Santana er hendes forlovede, men Almas forbehold er for stærk, og hun afviser deres forlovelse. New Directions-medlemmerne, både gamle og nye, fejrer sammen med Will Schuester (Matthew Morrison), Brittany og Santanas kærlighed.
Produktion
Ken Jeong og Jennifer Coolidge gæsteoptrædener som Brittanys forældre, Pierce og Whitney. Ivonne Coll gentog hendes rolle som Alma Lopez, bedstemor til Santana Lopez.
Tilbagevendende tilbagevendende figurer, der vises i episoden omfatter Heather Morris som Brittany Pierce, Naya Rivera som Santana Lopez, Becca Tobin som Kitty Wilde, Samantha Marie Ware som Jane Hayward, Noah Guthrie som Roderick, Marshall Williams som Spencer Porter , Billy Lewis Jr. som Mason McCarthy og Laura Dreyfuss som Madison McCarthy .
Episoden har otte musikalske coverversioner. Al musik fra denne episode blev skrevet og / eller komponeret af Burt Bacharach . "I'll Never Fall in Love Again" af Dionne Warwick blev sunget af Michele og Overstreet. "Baby It's You" af The Shirelles blev sunget af Riley med Michele, Morris og Rivera. "Wishin' and Hopin'" af Dionne Warwick blev sunget af Morris, McHale, Criss og Overstreet. "Arthur's Theme (Best That You Can Do)" af Christopher Cross blev sunget af Criss, McHale, Williams, Guthrie, Lewis Jr., Overstreet, og Colfer. "(They Long to Be) Close to You" af The Carpenters blev sunget af Overstreet. "Promises, Promises" fra musicalen Promises, Promises blev sunget af Michele. "Alfie" af Cilla Black blev sunget af Rivera. "What the World Needs Now Is Love" af Jackie DeShannon blev sunget af alle de førnævnte kunstnere og Morrison, med undtagelse af Morris og Rivera.
Modtagelse
Vurderinger
Episoden blev set af 1.580.000 amerikanske seere og modtog en bedømmelse på 0,5 ud af 2 af de voksne mellem 18-49.
Kritisk respons
Lauren Hoffman fra Vulture tænkte at "forestillingerne er temmelig flade", men kommenterede senere at "det føles som et par korte uger fra nu, selv efter at vi har sagt farvel til disse figurer, vil de stadig eksistere på hinandens sofaer, grine og synge i en glad bunke."
Referencer
Eksterne links
Episoder af Glee | danish | 0.556416 |
mouldy_food_sick/what-to-do-when-you-see-mold-on-your-food.txt | Skip to content
* * * Newsletters
* Subscribe
* Menu
Premium
* SCIENCE
# What to do when you see mold on your food
Can one fuzzy berry ruin the bunch? Can you cut away a spotty piece of bread
from the loaf? This is what the experts recommend.
Sometimes, the decision to keep or toss moldy food isn’t so cut and dry.
Though mold is often a sign the food is spoiled, there are exceptions.
Photograph by Jon Snedden, Camera Press/Redux
By Leah Worthington
November 10, 2023
• 7 min read
* * * *
So, you splurged on a carton of raspberries yesterday, and already they’re
starting to look a little…fuzzy. But it would be such a waste to throw them
out—maybe you can just pick out the moldy ones? Not so fast.
As innocuous as a few dusty patches might seem, foodborne mold can cause a
host of issues, from indigestion to—in the most extreme situations—kidney
damage or even cancer.
Of course, not all mold is out to kill you. In fact, most mold you see on your
food is harmless, but it’s nearly impossible to visually discern what’s safe
from what could make you sick. And some foodborne mold may not be visible at
all.
Still, a little household maintenance can go a long way—from kitchen
sanitation to food storage. Here’s your expert guide to best household
practices to extend your food life and protect your gut.
## Science of mold
Mold is everywhere—on surfaces, in the air, in the soil. From the acidic brine
of pickle juice to the grout between your bathroom tiles, mold can thrive in
even the most inhospitable environments.
Although they can survive in less, molds are happiest in warm, humid,
nutrient-rich environments, according to Elisabetta Lambertini, a senior
research scientist at the Global Alliance for Improved Nutrition. Think of
that steaming sourdough loaf or half-eaten apricot jam as an all-you-can-eat
buffet for a hungry mold.
Because molds reproduce by releasing clouds of microscopic spores, they can
travel anywhere accessible by wind or water. In fact, the average person
inhales between 1,000 and 10 billion spores per day . With billions of
spores floating around us, the only place foodborne mold won’t grow is
unopened, airtight jarred or canned foods. However, there are some easy
strategies to slow the inevitable growth process. For a quick rule of thumb,
Lambertini refers to the core four practices for food safety: clean, separate,
cook, and chill.
“Temperature is a big one,” says Don Schaffner, chair of the department of
food science at Rutgers University. “Microorganisms are just little bags of
chemical reactions, right? So by lowering the temperature, we just slow all of
that down.”
Refrigerating or freezing certain foods, like bread or other baked goods, can
maximize their shelf life. Be sure to keep your fridge around 35-38 degrees F,
and avoid overfilling to allow for sufficient airflow, which removes moisture
and prevents mold growth, Lambertini advises.
When possible, cover food to keep out airborne spores and store items,
particularly those with high water content, separately, in clean, closed
containers to prevent possible cross-contamination. Regularly cleaning your
fridge, countertops, and sponges will also minimize build-up or spreading of
mold colonies, she adds—common household products like vinegar or diluted
bleach will do the trick.
Of course, some foods are more mold-friendly than others—produce being a prime
example. One easy way to minimize that pesky fruit- and vegetable-borne mold
is to wash your produce only prior to consuming it.
“Because they’re so susceptible to getting moldy, you certainly want to rinse
off berries before you eat them,” Schaffner says. But wash them right from the
grocery store and you risk storing them with residual water.
Allium vegetables (like onion and garlic) are particularly prone to black
mold, a soil fungus, according to University of Wisconsin-Madison mold
geneticist Jae-Hyuk Yu. While black mold can be safely washed or cut off, he
suggests storing onions and garlic in netted bags that allow plenty of
ventilation. Keep them in the fridge for maximum mold prevention, he says.
## What kinds of mold are common in the house?
There are thousands of different mold species, including a wide variety that
might worm their way into your pantry.
## You May Also Like
SCIENCE
### Your gut health can affect the rest of your body. Here’s why.
SCIENCE
### There’s another biome tucked inside your microbiome—here’s why it’s so
important
SCIENCE
### The holidays can take a toll on your gut health. Here’s how to deal.
Of these potential kitchen offenders, only some produce toxins. For instance,
Yu says, Penicillium growth on apples and Aspergillus growth on grapes and
coffee produce mycotoxins that, even from acute exposures, can cause
poisoning or kidney damage . Consumption of high levels of aflatoxin, the
most dangerous mycotoxin, can cause severe toxicity or—with prolonged
exposure— even liver cancer .
Thankfully, Lambertini says, “These are generally not the type of molds that
grow in your fridge.”
In fact, the majority of molds growing visibly on food in the U.S. are
completely harmless. The bad news: It’s nearly impossible to pick out the
dangerous ones.
“Accurate mold identification requires microscopy observation and other
laboratory techniques, and is best left to trained professionals,” Lambertini
says. Better to assume they’re toxic.
Mold is not always visible to the naked eye. The fungus can grow deep into a
food before ever producing the billions of spores that create that familiar
greenish white fuzzy layer. Just because you can’t see it, doesn’t mean it’s
not there.
Fortunately our taste buds can be more discerning than our eyes. Even if you
didn’t spot anything wrong before you took a bite, Schaffner says a “funky”
taste is a good indication that something’s not right.
## What to do if you find mold on your food
What should you do if you notice a bit of unwanted growth? Which foods are
salvageable and which are better off as worm-feed?
“A big part of it is the nature of the food,” says Schaffner. With dense hard
foods like hard cheese or carrots, where you can clearly see the mold colony,
he says it’s safe to cut away the moldy part plus an extra inch or so.
However, in moister foods—soft cheese, yogurt, jams, pickles, hummus—the
extent of the mold growth is less obvious and hard to safely remove. “We can
see the mold colony on top, but there's also a part of the mold that's
underneath,” he says. Resist the urge to scoop it off; go straight to the
compost bin.
Same goes for moldy meat and fish. As tempting as it might be to try to freeze
or cook the growth away, that will only kill the fungus, leaving any toxins it
produced unscathed.
For bread, Schaffner allows that you might be able to get away with trimming
off the fuzz. But even then, it’s possible that the mold has grown deeper into
the loaf. To avoid inhaling a cloud of spores, Yu advises sealing and
immediately throwing away any loaf at the first sign of mold.
As for berries, it depends on the amount of visible mold. If it’s just an
isolated berry or two, tossing those and washing the rest is fine, Yu says.
But anything more than that is risky since it’s hard to see the full extent of
the mold growth.
A bit of mold growth can also be a useful signal, Lambertini adds, describing
it as “the ‘canary in the mine’ of food safety.” In other words, where there’s
mold, there’s likely to also be bacteria or a looming expiration date.
## What should you do if you accidentally eat food with mold on it?
Odds are that patch of mold you accidentally swallowed isn’t toxic, and even
if it is, a small amount isn’t cause for panic.
Still, experts suggest monitoring for symptoms like nausea, diarrhea, and
shortness of breath, and seeking medical help if you feel unwell. For those
who are immune-compromised, Yu advises seeing a doctor about any possible
consumption or inhalation of mold. (And don’t forget to bring a sample of the
culprit for closer inspection.)
Ultimately, learning to live with molds is a necessary part of being human. As
Schaffner puts it, molds “have been here longer than us and [will] be here
after we're gone.”
## Related Topics
* FUNGI
* FOOD WASTE
* MICROORGANISMS
* MICROBIOLOGY
* BACTERIA
* FOOD
## You May Also Like
SCIENCE
### Probiotics, prebiotics, postbiotics. What’s the difference?
HISTORY MAGAZINE
### This 'bacteria hunter' discovered the causes of tuberculosis, anthrax,
and cholera
MAGAZINE
### This Scientist Is Unlocking the Mysteries of Cheese
SCIENCE
### Food allergies are on the rise—but new treatments are on the horizon
MAGAZINE
### An Innovative Way to Keep Fruit Fresh
## Go Further
### Animals
* This fungus turns cicadas into zombies who procreate—then die
* Animals
This fungus turns cicadas into zombies who procreate—then die
* How can we protect grizzlies from their biggest threat—trains?
* Animals
How can we protect grizzlies from their biggest threat—trains?
* This ‘saber-toothed’ salmon wasn’t quite what we thought
* Animals
This ‘saber-toothed’ salmon wasn’t quite what we thought
* Why this rhino-zebra friendship makes perfect sense
* Animals
Why this rhino-zebra friendship makes perfect sense
* When did bioluminescence evolve?
* Animals
When did bioluminescence evolve?
* The clouded tiger-cat is new to science—and under threat
* Animals
* Photo Ark
The clouded tiger-cat is new to science—and under threat
### Environment
* Your favorite foods may not taste the same in the future. Here's why.
* Environment
Your favorite foods may not taste the same in the future. Here's why.
* Are the Great Lakes the key to solving America’s emissions conundrum?
* Environment
Are the Great Lakes the key to solving America’s emissions conundrum?
* The world’s historic sites face climate change. Can Petra lead the way?
* Environment
The world’s historic sites face climate change. Can Petra lead the way?
* England’s iconic chalk streams are in trouble
* Environment
England’s iconic chalk streams are in trouble
* This pristine piece of the Amazon shows nature’s resilience
* Environment
* Perpetual Planet
This pristine piece of the Amazon shows nature’s resilience
* 30 years of climate change transformed into haunting music
* Environment
30 years of climate change transformed into haunting music
### History & Culture
* When treasure hunters find artifacts, who gets to keep them?
* History & Culture
When treasure hunters find artifacts, who gets to keep them?
* The short, sweet, and sticky history of jam
* History & Culture
The short, sweet, and sticky history of jam
* Meet the original members of the tortured poets department
* History & Culture
Meet the original members of the tortured poets department
* 5 fascinating facts about Zoroastrianism
* History & Culture
5 fascinating facts about Zoroastrianism
* When America's first ladies brought séances to the White House
* History & Culture
When America's first ladies brought séances to the White House
* Gambling is everywhere now. When is that a problem?
* History & Culture
Gambling is everywhere now. When is that a problem?
### Science
* Quieting your mind to meditate can be hard. Here’s how sound can help.
* Science
Quieting your mind to meditate can be hard. Here’s how sound can help.
* Should you be concerned about bird flu in your milk?
* Science
* Mind, Body, Wonder
Should you be concerned about bird flu in your milk?
* Can vitamin D help fight cancer?
* Science
* Mind, Body, Wonder
Can vitamin D help fight cancer?
* Why alien life might look purple
* Science
Why alien life might look purple
* Here's how astronomers found one of the rarest phenomenons in space
* Science
Here's how astronomers found one of the rarest phenomenons in space
* Not an extrovert or introvert? There’s a word for that.
* Science
* Mind, Body, Wonder
Not an extrovert or introvert? There’s a word for that.
### Travel
* These are the best dishes to eat in Glasgow
* Travel
These are the best dishes to eat in Glasgow
* Germany's iconic castle has been renovated. Here's how to see it
* Travel
Germany's iconic castle has been renovated. Here's how to see it
* Is this the prettiest city in Lithuania?
* Paid Content
Is this the prettiest city in Lithuania?
* This tomb diver was among the first to swim beneath a pyramid
* Travel
This tomb diver was among the first to swim beneath a pyramid
* Food writer Dina Macki on Omani cuisine and Zanzibari flavours
* Travel
Food writer Dina Macki on Omani cuisine and Zanzibari flavours
* How to see Mexico's Baja California beyond the beaches
* Travel
How to see Mexico's Baja California beyond the beaches
#### Legal
* Terms of Use
* Privacy Policy
* Your US State Privacy Rights
* Children's Online Privacy Policy
* Interest-Based Ads
* About Nielsen Measurement
* Do Not Sell or Share My Personal Information
#### Our Sites
* Nat Geo Home
* Attend a Live Event
* Book a Trip
* Buy Maps
* Inspire Your Kids
* Shop Nat Geo
* Visit the D.C. Museum
* Watch TV
* Learn About Our Impact
* Support Our Mission
* Masthead
* Press Room
* Advertise With Us
#### Join Us
* Subscribe
* Customer Service
* Renew Subscription
* Manage Your Subscription
* Work at Nat Geo
* Sign Up for Our Newsletters
* Contribute to Protect the Planet
#### Follow us
National Geographic Instagram National Geographic Facebook National
Geographic Twitter National Geographic Youtube National Geographic Linkedin
National Geographic Tiktok National Geographic Reddit
United States (Change)
* * *
Copyright © 1996-2015 National Geographic Society Copyright © 2015-2024
National Geographic Partners, LLC. All rights reserved
| biology | 381005 | https://no.wikipedia.org/wiki/Amerikansk%20alligator | Amerikansk alligator | Amerikansk alligator (Alligator mississippiensis) er en av to arter alligatorer som lever i dag, hvor den andre er kinesisk alligator.
Den amerikanske alligatoren lever i de sørøstlige delene av USA. Den er også større enn den kinesiske alligatoren. Alligatorer er generelt mindre aggressive enn de store krokodillene, spesielt nilkrokodillen og saltvannskrokodillen, men i motsetning til hunnkrokodillen tar hunnalligatoren seg av avkommet sitt til det er omtrent to år gammelt, hvilket gjør en hunnalligator med barn svært aggressiv og farlig.
Historie
Forskere sier at arten er mer enn 150 millioner år gammel, og at den klarte å unngå utryddelse da dinosaurene døde ut for rundt 65 millioner år siden.
Biologi og oppbygning
Størrelse
De amerikanske alligatorene er de største reptilene i USA. Hann-alligatorer kan bli så lange som 4,5 meter, mens hunn-alligatorer kan bli i underkant av 3 meter.
Kroppstemperatur
Alligatorer er ektoterme dyr som er avhengig av varme utenfra for å regulere kroppstemperaturen.
Tenner
En voksen alligator har mellom 74 og 84 tenner i munnen. Hvis en tann slites eller brytes av, vokser det ut en ny. Det antas at alligatorer går gjennom 2000 til 3000 tenner i løpet av livet.
Tær og klør
Alligatorene har fem «tær» på hver forarm og 4 tær på hver av føttene bak. Det er kun klør på de tre første tærne foran og de tre første bak på hver arm og hvert ben.
Rygg
Ryggen deres er dekket i noe som kalles for osteodermer, som betyr beinhud. Dette er beinavleiringer som danner skalaer, plater eller andre strukturer basert i dermis. Disse fungerer som en slags rustning og er kroppsbeskyttelse. De er så harde at mange dyr ikke klarer å fordøye dem.
Luktesans, syn, hørsel
Alligatorens luktesans, syn og hørsel er bemerkelsesverdig. Dyrene kan også «føle» når noe er i nærheten. Dette skyldes deres spesialiserte sensoriske nervestrukturer som oppdager berøring, overflatetemperatur og smerte, noe som er en biologisk fordel. Disse strukturene finnes i de små svarte prikkene de har på underkjeven som kalles integrerte sensoriske organer. Denne fordelen benytter alligatoren seg av da blant annet på jakt etter fisk i grumsete vann hvor den kun kan føle byttet sitt og ikke se det.
Alligatoren er utstyrt med en øyemembran som kan åpnes og lukkes etter behov. Denne membranen fungerer som svømmebriller når den er unner vann. Den tar også i bruk membranen i jaktsituasjoner for å beskytte øynene sine. Alligatoren renser øynene sine ved å fukte dem. Øynene deres "gløder i mørket", siden de har en lysreflekterende overflate bakerst i øyet kalt «Tapetum Lucidum», noe som gir dem nattsyn. Mange andre dyr har også dette, eksempelvis katter.
Selv om man ikke ser noen definerte ører på alligatorer, slik man gjør på for eksempel elefanter, har alligatorene også ører. De ligger rett bak øynene, og kan lukkes og åpnes når det trengs. Alligatorer har svært god hørsel, noe som er nyttig for å få med seg bevegelser i vannet ved blant annet jakt.
Reproduksjon
De fleste hunn-alligatorer legger mellom 35 og 50 egg, men dette varierer ut fra alligatorens helse og alder. Rekorden for hvor mange egg som noensinne har blitt registrert er 90 egg. Alligatorhunnen legger eggene på land; hadde hun lagt egg under vann ville eggene ha sunket.
Nyfødte alligatorer er som oftest mellom 15 og 20 cm lange, og de har gule og svarte striper. Nyfødte alligatorer blir ofte spist av rovdyr, deriblant fugler, vaskebjørner, rødgaupe og til og med andre alligatorer. Moren tar seg av ungene frem til fde er ett år eller to gamle; deretter må de klare seg på egenhånd.
Kjønnet på alligatorer bestemmes ut ifra temperaturen der eggene klekkes. Dette er et fellestrekk for flere reptiler og noen fiskeslag; på engelsk betegnes fenomenet som «Temperature-dependent sex determination (TSD)».
Levetid
Alligatorer lever som oftest mellom 30 til 50 år i det fri, men kan leve lenger i fangenskap.
Diett og jakt
Alligatorer spiser nesten alt de kommer over, men favorittmaten er fisk, skilpadder, fugler, små pattedyr og amfibier.
De fleste alligatorer kan gå over et år uten å spise noe, dersom det foreligger et behov for det i det ville.
De bruker de skarpe tennene sine for å fange bytte, og kjevene deres er så sterke at de kan knekke et skilpaddeskall. En stor og fullvoksen alligator har en bitestyrke på over 2000 pund per kvadrat tomme – noe som er nok til å bite gjennom stål. Tennene deres er ikke spesielt skarpe, og de bruker for det meste bare tennene for å bite i kjøttet på byttet. Tennene fungerer som en gaffel som holder byttet på plass. Det er mengden bitestyrke som knekker byttets bein, og til slutt gjør de en "death roll" (dødsrulle) for å rive deler av kjøtt ifra resten av kroppen.
Habitat
I dag er alligatorer funnet i et område som strekker seg fra Merchants Millpond State Park i Nord-Carolina til Rio Grande i Texas og i deler av Oklahoma. De største forekomstene av alligatorer finnes i Florida og Louisiana. Det finnes mange oppdrettsanlegg for alligatorer i USA, og både kjøttet, skinnet og hodene omsettes i kommersiell handel.
Den amerikanske alligatoren lever i ferskvannsmiljøer, hovedsakelig i sumper og myrer.
Forhold til mennesker
Alligatorer er ikke i utgangspunktet farlig for mennesker, og de ser ikke på mennesker som en normal og naturlig matkilde. Det er veldig sjelden alligatorer oppsøker mennesker i den hensikt å spise eller skade menneskene. Det er hovedsakelig to grunner til at alligatorer opptrer fiendtlig overfor mennesker:
Alligatorer som har blitt foret kan potensielt være truende for mennesker. Foringen fører til at de ser på mennesker som en matkilde, og de mister sin naturlige frykt for mennesker. De begynner å assosiere mat med mennesker, og hvis et menneske uten mat møter en matet og sulten alligator, kan den angripe (spesielt hvis personen er liten). I Florida er det blant annet ulovlig og straffbart å mate alligatorer og krokodiller. Alligatorer som har blitt foret må ofte avlives, fordi de er for pågående og mange ser på dem som truende.
Svømming i alligatorens habitat, hvor man da ser ut som et lite bytte og mat som den er vant til å spise i området. Alligatorens øyne er over vannet, og for den ser en svømmende person ut som bytte.
Forskjellen på alligatorer og krokodiller
Krokodillen er større i størrelse og har en mer V-formet snute, mens alligatorer er mindre og har en bredere og U-formet snute. I tillegg til dette kan man se både noen tenner oppe og nede når munnen til krokodillen er fullt lukket, mens på alligatoren ser man kun de øvre tennene. Fargen på reptilene er også forskjellig; krokodillen er olivengrønn eller brunfarget, mens alligatoren er mørkegrå eller tilnærmet sort. Krokodiller er på generell basis mer aggressive overfor mennesker enn det alligatorer er, men dette kommer helt an på typen krokodille. Den amerikanske krokodillen er et eksempel på en mindre aggressiv art.
Referanser
Eksterne lenker
Krokodiller
Dyr formelt beskrevet av François Marie Daudin
Krypdyr formelt beskrevet i 1802 | norwegian_bokmål | 0.980307 |
dog_eyes_glow/canine-eyes-their-disorders.txt | Common Eye Problems in Dogs and How to Treat Them · The Wildest
Skip to main content
# Common Eye Problems in Dogs and How to Treat Them
Your dog sees you as their best friend, so keep those eyes healthy.
by Shauna S. Roberts, PhD opens in a new tab and Dr. Alycia Washington,
DVM, MS opens in a new tab
Updated November 28, 2023
ownza / Adobe Stock
## share article
Twitter Opens a new window Facebook Opens a new window Pinterest Opens a
new window Email Opens a new window
Your pet wants you to read our newsletter. (Then give them a treat.)
Enter email address
I'm In
Sign up for product updates, offers, and learn more about The Wildest, and
other Mars Petcare brands . Must be over 16 years to sign up. See our
privacy statement to find out how we collect and use your data, to contact us
with privacy questions or to exercise your personal data rights.
Dogs are susceptible to a variety of eye disorders, some of which can be
serious and lead to vision loss. Eye diseases seen in dogs include
conjunctivitis, dry eye, corneal ulcers, cataracts, glaucoma, and retinal
disorders. Early detection and treatment are essential for the best outcome.
If you notice any changes in your dogâs eyes, such as redness, swelling,
discharge, squinting, or tearing, it is important to see a veterinarian right
away.
â Puppy-dog eyes opens in a new tab â get dog parents every time.
Itâs been proven that gazing opens in a new tab into your petâs eyes
produces oxytocin and promotes bonding. They are the epitome of the
âpleading faceâ emoji. Irresistible.
It could be something more than cuteness, though. If your dogâs eyes have
been looking a little red or cloudy lately or if youâve noticed theyâre
pawing at, rubbing, or showing signs of irritation around their eyes, you
might need to make an appointment with your vet.Â
âAs a general practitioner, I was often presented with problems such as
conjunctivitis, dry eye, and corneal ulcer,â says Dr. Christine Lim, a
veterinarian in Chicago. âNow that I specialize in ophthalmology, I more
often see cataracts, glaucoma, and retinal disorders.â
Related article
opens in a new tab
### Dogs Get Dry Eye Too...Some Breeds More Than Others opens in a new tab
Eyes without tears are only for Cameron Diaz in The Holiday .
## What are the most common eye problems in dogs?Â
Eye problems in dogs are no joke â dogs can suffer from a host of health
conditions including glaucoma, conjunctivitis, dry eyes, cataracts, and more.
Some eye disorders occur more often than others and a dogâs breed usually
plays a role in that. Common eye problems in dogs include:Â
1. Eye infections
2. Dry eyeÂ
3. Cataracts
4. Glaucoma
5. Corneal ulcers
6. Uveitis
7. Conjunctivitis
8. Watery eyes
9. Entropion/Ectropion
10. Bulging EyesÂ
11. Cherry eye
12. Lazy eye
13. Retinal Disorders
## How dogsâ eyes work
To understand eye problems in dogs, it helps to know a little bit about how
their eyes function. A dogâs eyes work much like a camera. Light first
enters through the clear cornea then passes through the pupil. The iris
controls the amount of light allowed in through the pupil. Next, light goes
through the lens, which focuses the light on the retina â a layer containing
color-sensitive cones and motion- and light-sensitive rods, which convert
light into electrical signals. The cones and rods send these signals via the
optic nerve to the brain, which constructs an image from them.
Dogs have only two types of cones, compared with the three types in human
eyes. As a result, dogs donât see as many colors as people opens in a new
tab do. Dog eyes also contain structures not found in a camera, such as the
gel-like vitreous humor that fills the eyeball and gives it shape. Canine eyes
are different from human eyes in that they have a third eyelid, called the
nictitating membrane, which is a thin whitish-pink tissue that protects the
eye. And unlike humans, dogs have a reflective lining behind the retina called
the tapetum lucidum; itâs what makes dogsâ eyes glow eerily when light
hits them. Itâs also what allows them to see in dimmer light.
Related article
opens in a new tab
### Dog Vision: What Colors Do Dogs See? opens in a new tab
They canât take in as many colors as you can, but their world isnât just
black and white.
The visual streak is a horizontal band in the retina right above the optic
nerve; this area has the highest concentration of rods and cones, and vision
is sharpest here. The visual streak varies greatly among breeds, and studies
suggest that different breeds see the world differently. In dogs with long
heads like wolves, the streak is wide, with the nerves evenly distributed. The
shorter a breedâs head, the narrower (more circular) the streak tends to be.
Pugs, for example, have a small spot of sharp vision â an âarea
centralisâ â like humans do. Even within breeds, the visual streak can
vary from type to type.
## How well do dogs see?
All of these features equip a dog to be a good hunter under various light
conditions. The tapetum lucidum improves a dogâs vision in low light, as
does the high proportion of rods to cones, giving dogs better vision at night
opens in a new tab than humans. A rod-dense retina also makes dogs excellent
at detecting motion and shapes. Because most dogsâ eyes angle slightly to
the side, they have a wider field of view than humans. When a wide field of
vision combines with a wide visual streak, as in a German Shepherd, a dog can
see the whole horizon at once (instead of having to scan the eyes back and
forth as humans do).
With keen senses of smell and hearing, dogs donât need to see well up close;
in fact, near vision is blurry in long-nosed dogs. Short-nosed dogs, with
their human-like area centralis, do appear to see well up close. Though the
area centralis may lessen their ability as hunters, it may make them better
lap dogs, more able to âreadâ their parentsâ faces. Overall, dog vision
is less sharp than human vision.
## What are the signs of eye problems in dogs?
Dog parents may be cued into an issue with their dogâs eye if it changes in
appearance or if their dog seems to be experiencing eye irritation. Any
concerns about a dogâs eyes should not be ignored. Signs of eye problems in
dogs include:
* Squinting
* Eye discharge (especially if it is not clear)
* Eye redness
* Cloudiness
* Pawing at the eyeÂ
* Sudden change in vision (bumping into things, anxiety, hesitation to walk)
* Swollen eyes
* Bulging eyes
* Persistently dilated or constricted pupils
Related article
opens in a new tab
### Everything You Need to Know About Cataracts in Dogs opens in a new tab
Hereâs how to spot the eye condition and help your dog see more clearly.
## What are the dog breeds prone to eye problems?
While eye issues can affect any dog, certain breeds face a greater risk.
Brachycephalic (smoosh faced) dogs breeds are prone to eye problems.
Brachycephalic breeds opens in a new tab include Pugs, French Bulldogs,
English Bulldogs, Boston Terriers, Lhasa Apsos, and Bullmastiffs. The skull
shapes in these dogs not only contribute to a higher risk for respiratory
problems, but they have a higher incidence of eye issues as well. Their eyes
bulge out more, contributing to a host of issues often lumped together as
brachycephalic ocular syndrome.Â
Dogs with brachycephalic ocular syndrome tend to have shallow eye sockets,
contributing to eyes that are more likely to pop out as a result of trauma
(proptosis). They are also more likely to have dry eyes and corneal ulcers,
either from low tear production or from an inability to close their eyes all
the way. Eyelid issues like entropion and trichiasis cause facial hairs to
constantly scrape the eyeâs surface, causing discomfort and trauma to the
cornea.Â
### Common dog eye problems
Dog eyes are susceptible to a variety of issues. Some can be easily addressed
by your veterinarian while others may call for a referral to a veterinary
ophthalmologist. Here are some of the most common eye problems in dogs:
### Eye infections
Viral and bacterial eye infections are commonly diagnosed in dogs. Fungal eye
infections occur in dogs but are less common. Eye infections can affect the
conjunctiva (the pink tissue around the eye) or the eye itself. Symptoms of
eye infections include yellow or green eye discharge, crusting around the
eyes, redness, and discomfort. Treatment often involves administering
medicated eye drops. Depending on the severity and type of infection, oral
medications may be prescribed, too.Â
Related article
opens in a new tab
### Whatâs This Weird Red Bump On My Dogâs Eye? opens in a new tab
That would be a cherry eye, and youâll want to see your vet.
### Dry eye
Dry eye occurs when not enough tears are produced to keep the eyes properly
lubricated. Dogs may inherit this condition; among the dog breeds at higher
risk are the American Cocker Spaniel, English Bulldog, Pug, Lhasa Apso,
Pekinese, Shih Tzu, and West Highland White Terrier. Small, flat-faced dogs
sometimes have eyes that bulge so much that their eyelids cannot close, which
makes the surface of the eyes to dry out.
Dry eye opens in a new tab may also result from an immune system reaction,
an injury, or a drug side effect. Dryness can be a serious problem for dogs
because dry eyes are easily irritated and may develop conjunctivitis or
corneal ulcers. Artificial tears, good eye hygiene, anti-inflammatory drugs,
and/or cyclosporine ointment (Optimmune) may help.
### Cataracts
The most common cause of blindness in dogs, a cataract is a clouding of the
lens that obscures the dogâs vision. Most dogs with cataracts opens in a
new tab inherited the tendency to develop them. Inherited cataracts can occur
in the Afghan Hound, American Cocker Spaniel, Boston Terrier, Chesapeake Bay
Retriever, German Shepherd, Golden Retriever, Labrador Retriever, Miniature
Schnauzer, Norwegian Buhund, Old English Sheepdog, Schnauzer, Siberian Husky,
Staffordshire Bull Terrier, Standard Poodle, Welsh Springer Spaniel, and West
Highland White Terrier. Diabetes opens in a new tab , injuries, poor diet
opens in a new tab , and aging can also lead to cataracts.
Surgery is available to treat dogs with cataracts. Removing the lens allows
light to enter the eye again. For best post-surgery vision, the natural lens
is usually replaced by a plastic lens. âThe surgery itself is not too
stressful for the majority of patients,â says Dr. Lim. However, âthe first
few weeks postoperatively can be stressful because it is very intensive â
the patient must wear an Elizabethan collar at all times, and several
medications are required.â
### Glaucoma
Glaucoma is the elevated pressure created by the fluid inside the eyeball
draining more slowly than it is produced. Dogs with glaucoma can experience
damage to the retina or optic nerve.
Most often, dogs get glaucoma because they inherited an eye structure that
leads to poor drainage. Dog breeds in which primary (inherited) glaucoma
occurs include the Alaskan Malamute, American Cocker Spaniel, Basset Hound,
Beagle, Boston Terrier, Bouvier des Flandres, Chow Chow, Dalmatian, English
Cocker Spaniel, English Springer Spaniel, Great Dane, Labrador Retriever,
Norwegian Elkhound, Poodle (all sizes), Samoyed, Shar-Pei, Shih Tzu, Siberian
Husky, and Welsh Springer Spaniel.
Primary glaucoma has no obvious cause, and it affects both eyes (although one
eye may develop glaucoma earlier than the other). Secondary glaucoma is
glaucoma that is caused by a dislocated lens, injury, tumor, or other problem
that decreases fluid drainage in the eye; it may affect just one eye.
Glaucoma treatments include surgery, pills, eye drops, or (rarely) removal of
the eyeball. âGlaucoma is still one of the more difficult things to
handle,â says Dr. Vainisi. âEven though there are literally dozens of
glaucoma procedures, there still is not that ideal oneâ¦even in humans.â
Related article
opens in a new tab
### How to Find a Veterinary Specialist opens in a new tab
Just like your doctor would refer to you a specialist for expert care for a
complicated issue, your vet may do the same for your dog.
### Corneal ulcers
Corneal ulcers are slow-healing sores on the dogâs cornea, accompanied by
inflammation. Most ulcers are caused by injuries, and treatment often involves
antibiotics. Small dog breeds with very short noses and big eyeballs are more
prone to eye injuries, says Dr. Samuel J. Vainisi, DVM, ACVO of the Animal Eye
Clinic in Denmark, Wisc. âBecause of that, we see a lot of ulcers on the
eyes of breeds such as the Boston Terrier, the Pekinese, and the Shih Tzu.â
### Uveitis
Uveitis opens in a new tab refers to inflammation inside of the eye. This
inflammation typically stems from the eyeâs blood vessels. Uveitis usually
develops secondary to another cause including trauma, infection, tick-borne
disease, auto-immune disease, or metabolic disease. Uveitis can cause pain in
dogs, and the symptoms often reflect this discomfort. Symptoms of uveitis in
dogs include squinting, rubbing the eyes, and ocular discharge. The eyes can
appear red or cloudy. Treating uveitis involves addressing the inflammation
and treating the underlying cause.Â
### Conjunctivitis
Conjunctivitis is a condition in which the lining of the eyelids and the
sclera (the white of the eye) become inflamed. It can be caused by infection,
an object in the dogâs eye, an allergic reaction, dry eye, a scratch, or
even smoke or dust. It can also be a symptom of other diseases. Treatment
depends on the cause, but often entails addressing inflammation and infection.
### Watery eyes
Watery eyes, or epiphora, is commonly seen in dogs. Dogs develop epiphora for
two reasons â either excess tear production from eye irritation or more
tears present due to a lack of drainage. Eyes can become irritated from
allergies opens in a new tab , trauma, or infection. Normally, tears from
the eyes drain through the nasolacrimal duct into the nasal cavity. When
drainage is obstructed or poor, tears run down a dog's face instead. Tears can
stain the fur on the face, which is a cosmetic concern for some dog parents.
Clear tears and clear eyes are typically not considered to be a medical issue.
Excessive tears with signs of eye irritation should be evaluated by a
veterinarian.Â
Related article
opens in a new tab
### Dog Vision: What Colors Do Dogs See? opens in a new tab
They canât take in as many colors as you can, but their world isnât just
black and white.
#### Entropion/ectropion
Entropion occurs when one or both eyelids are inverted inwards. Entropion in
dogs can occur due to genetics, developmental abnormalities, or secondary to
eyelid trauma. Entropion is most commonly diagnosed in young, large breed
dogs. Breeds that are predisposed to entropion include Bull Mastiffs, Chow
Chows, Labrador Retrievers, Standard Poodles, Chesapeake Bay Retrievers, and
Shar Peis. Entropion can cause the eyelashes to rub on the cornea, causing
pain and trauma. Treatment often involves surgical correction.Â
Ectropion occurs when an eyelid is turned outward or when the lower eyelid
sags, creating minimal contact with the eye. Ectropion in dogs is typically
congenital. Breeds predisposed to ectropion include Saint Bernards,
Bloodhounds, Great Danes, and Spaniels. Picture droopy eyed dogs. When they
blink, their lower eyelids do not make adequate contact with their eyes and
cannot help with lubricating the cornea or wiping away irritants. Over time,
the eyes can become dry and inflamed. Treatment can range from temporary anti-
inflammatory medications to chronic eye lubricant application to corrective
surgery.Â
### Bulging eyesÂ
Dogâs eyes can bulge as a result of trauma or underlying medical conditions
like glaucoma. A bulgy eye appearance can be from proptosis (displacement of
the eye) or buphthalmos (enlargement of the eye). A dogâs eyes should be the
same size and rest comfortably in their eye sockets. Any change to this state
is considered a medical emergency.
### Cherry eye
Dogs have a nictitating membrane, commonly called the third eyelid, that aids
in tear production and eye protection. When this gland becomes displaced and
protrudes, itâs called a cherry eye opens in a new tab and looks like
smooth, pink tissue protruding from the inside corner of the eye. This limits
the tear production in the eye and can cause dryness and irritation. The
exposed tissue also becomes inflamed. While mild cases may be treated
medically, surgical replacement is often recommended to address cherry eye.
Any dog can develop a cherry eye, but brachycephalic breeds like English
Bulldogs and Shih Tzus have a higher risk.Â
### Lazy eye
Strabismus refers to having eyes that donât face the same direction. This is
usually due to incoordination of the eye muscles. Strabismus in dogs is often
genetic and does not cause any health issues; most dogs born with a lazy eye
do not require any treatment. A dog that suddenly develops a lazy eye should
be evaluated. A sudden change in eye position can develop as a result of
tumors in or near the eye, neurological problems, or trauma. Treatment for
acute strabismus in dogs depends on the cause.Â
### Retinal disorders
Progressive retinal atrophy (PRA) is the name for a group of retinal disorders
in which rods and cones die off. There is no treatment for this condition.
Dogs who get PRA do so because theyâve inherited a defective gene. Although
PRA strikes more than 100 breeds of dogs, different genes can be responsible
for it. Therefore, breeds differ in the age at which the condition appears,
how fast the condition progresses, and the ratio of males to females among
affected dogs.Â
Related article
opens in a new tab
### Everything You Need to Know About Cataracts in Dogs opens in a new tab
Hereâs how to spot the eye condition and help your dog see more clearly.
PRA appears during puppyhood in the Cardigan Welsh Corgi, Cairn Terrier,
Collie, Gordon Setter, Great Dane, Irish Setter, Miniature Schnauzer and
Norwegian Elkhound. In contrast, some breeds usually donât develop PRA until
adulthood. These include the American Cocker Spaniel, English Cocker Spaniel,
Labrador Retriever, Lhasa Apso, Miniature Poodle, Portuguese Water Dog,
Tibetan Spaniel, and Tibetan Terrier. PRA occurs mostly in males in the
Siberian Husky and Samoyed. Genetic tests for PRA are available for several
breeds.
Other retinal problems include detachment of the retina from the back of the
eye, inflammation, and abnormal development. Causes include infection and
injury. Some retinal disorders have no treatment, while others can be helped
by surgery or treatment of the cause.
Small dogs may be more prone to retinal detachment. According to Dr. Vainisi,
several small breeds of dogs, including Boston Terriers, Jack Russell
Terriers, and Shih Tzus, love to pick up toys and shake them hard. âFluid
goes violently back and forth in the back of the eye, and it just rips the
retina right off,â he says. âOne moment theyâre seeing, and the next
moment they can be totally blind.â
### How to treat your dogâs eye problem
The best way to protect your dogâs vision is to catch eye disorders early
opens in a new tab , when they are most easily treated. A dog with eye or
vision problems may paw at or scratch their eye, squint, bump into things,
become afraid of the dark, or be frightened in situations that did not
frighten them before. The dogâs eye may produce discharge, be red, look
cloudy or be swollen. The nictitating membrane may partially cover the eye.
If your dog seems to have an eye problem, take them to the veterinarian right
away. Your vet may have the knowledge and equipment to diagnose and treat the
problem immediately; if not, they may refer your dog to a veterinary
ophthalmologist, a specialist in animal eyes and their disorders.
Related article
opens in a new tab
### Whatâs This Weird Red Bump On My Dogâs Eye? opens in a new tab
That would be a cherry eye, and youâll want to see your vet.
Only about 300 veterinarians in the United States have board certification
from the American College of Veterinary Ophthalmologists. As a result, if your
dog needs a veterinary ophthalmologist, you may need to travel to see one.
Some, but not all, veterinary ophthalmologists see dogs only by referral.
The bottom line: If your dog has an eye issue, make an appointment with your
vet right away. That way, your dog wonât need to suffer or develop a worse
issue unnecessarily.
## Can you prevent dog eye problems?Â
The best thing dog parents can do to protect their dogâs eyes is to minimize
risk of injury and prioritize overall health. Keep your dog away from other
animals that may not want to play nice. Donât let them hang around smoke or
any aerosols that can irritate their eyes.Â
Keep your pup up to date on vaccinations and preventatives to avoid infections
and tick-borne disease. Feed an appropriate diet and provide lots of exercise
to help prevent metabolic diseases like diabetes. Proactive petcare overlaps
with dog eye disease prevention.
## FAQs (People also ask):
### Can I use over-the-counter eye drops for my dog's eye problems?
Never apply any human medications to your dogâs eyes without consulting a
veterinarian first. Human medications are not formulated for dogs and may
include ingredients that can worsen your dogâs eye condition.Â
### Is there any home remedy available for eye problems in dogs?
If your dog has excessive eye discharge or crusty eye boogers, you can gently
wipe it away with a cotton ball or washcloth soaked in warm water. Be sure to
seek veterinary care to address the underlying cause of the discharge.Â
### When should I seek immediate veterinary care for my dog's eye issue?
Any eye issue should be addressed as soon as possible before it progresses to
something that can affect a dogâs vision. If your dogâs eyes change in
appearance or your dog vision seems suddenly impaired, seek veterinary
attention ASAP.Â
## References:
* Oxytocin-Gaze Positive Loop and the Coevolution of Human-Dog Bonds opens in a new tab
* Curiosities: How Well Do Dogs See at Night? opens in a new tab
* A Common Problems Of Dog Eyes (A Review) opens in a new tab
* Clinical Signs of Brachycephalic Ocular Syndrome in 93 Dogs opens in a new tab
* Prevalence of the Breed-Related Glaucomas in Pure-Bred Dogs in North America opens in a new tab
* Cote's Clinical veterinary Advisor: Dogs and Cats - E-Book opens in a new tab
* Nasolacrimal and Lacrimal Apparatus in Animals opens in a new tab
Tags
* dog opens in a new tab
* dog health opens in a new tab
* senior dog opens in a new tab
## Shauna S. Roberts, PhD
Shauna S. Roberts, PhD, is an award-winning science and medical writer and
copyeditor who specializes in arthritis, diabetes and related subjects.
Shauna S. Roberts, PhD opens in a new tab
## Dr. Alycia Washington, DVM, MS
Alycia Washington, DVM, is a small animal emergency veterinarian based in
North Carolina. She works as a relief veterinarian opens in a new tab and
provides services to numerous emergency and specialty hospitals. Dr.
Washington is also a childrenâs book author and freelance writer with a
focus on veterinary medicine. She has a special fondness for turtles, honey
bees, and penguins â none of which she treats. In her free time, Dr.
Washington enjoys travel, good food, and good enough coffee.Â
Dr. Alycia Washington, DVM, MS opens in a new tab
Website
## Related articles
* ### Diabetes in Dogs: Symptoms, Treatment, and Prevention
Learn which breeds are at risk, the symptoms to look out for, and what
treatment options are available.
opens in a new tab
* ### Why You Should Trim Your Dogâs Bangs
Hint: they canât see.
opens in a new tab
* ### How to Do a DIY Dog Checkup in 7 Steps
You can do a DIY exam on your dog from your couch.
opens in a new tab
* ### Dogs Get Dry Eye Too...Some Breeds More Than Others
Eyes without tears are only for Cameron Diaz in The Holiday .
opens in a new tab
* ### How to Do a DIY Dog Checkup in 7 Steps
You can do a DIY exam on your dog from your couch.
opens in a new tab
* ### How to Take Care of a Senior Dog
As dogs age, itâs important to recognize both physical and mental changes
they may be experiencing.
opens in a new tab
* Health opens in a new tab
* Nutrition opens in a new tab
* Behavior opens in a new tab
* Lifestyle opens in a new tab
* Grooming opens in a new tab
* Shopping opens in a new tab
* Tools opens in a new tab
* New Pet opens in a new tab
* * Poodle opens in a new tab
* About Us opens in a new tab
* Collective opens in a new tab
* Contact Us opens in a new tab
*
* Accessibility Opens a new window
* Terms of Service opens in a new tab
* Ad Choice Opens a new window
* Privacy Notice Opens a new window
* Your Privacy Choices
Opens a new window
* Cookie Management opens in a new tab
* Cookie Policy Opens a new window
Enter email address
Submit icon
Sign up for product updates, offers, and learn more about The Wildest, and
other Mars Petcare brands . Must be over 16 years to sign up. See our
privacy statement to find out how we collect and use your data, to contact us
with privacy questions or to exercise your personal data rights.
Facebook Instagram Tiktok Twitter
© 2024, Kinship Partners, Inc. an affiliate of Mars Incorporated | Ver. f1ab5a4
| biology | 66246 | https://no.wikipedia.org/wiki/Nova%20scotia%20duck%20tolling%20retriever | Nova scotia duck tolling retriever | Nova scotia duck tolling retriever, også kalt toller, er en vannapporterende hunderase som trolig oppsto i Nova Scotia-distriktet i Canada på siste halvdel av 1800-tallet. Tolleren er Nova Scotias provinshund.
Opprinnelse og alder
Nova scotia duck tolling retriever (toller) kan være et resultat av en krysning mellom en småvokst chesapeake bay retriever, golden retriever og en brun spanieltype, men dette vites ikke med sikkerhet. Andre teorier antyder at den kan være en krysning mellom en leverfarget flat coated retriever og en labrador retriever. Noen mener også at den kan være innblandet irsk setter og andre lokale hunder.
Parker et al. (2017) dokumeterer imidlertid at rasen er nært beslektet med andre retrievere, irsk vannspaniel og newfoundlandshund, samt at rasen har blitt tilført gener fra collie og/eller shetland sheepdog, noe som også forklarer hvordan den arvelige øyelidelsen CEA (collie eye anomaly) har tatt seg til denne hunderasen. Om shetland sheepdog inngår kan dette også forklare hvorfor denne retrieveren er mindre enn de andre, men om det kun er collie så må den reduserte størrelsen forklares med noe annet.
Rasen har fått sin utforming i Canada. CKC anerkjente rasen i 1945, som den første kennelklubben i verden. FCI anerkjente den som sådan i 1982 og AKC i 2001.
Rasen kom til Norge først i 1986 (Danmark/1982 – Sverige/1984). Den har de senere årene blitt stadig mer populær i Norge.
Utseende, anatomi og fysikk
Tolleren er den minste av retrieverne. Hannene blir gjerne ca. 48-52 cm i mankehøyde, mens tispene blir ca. 45-48 cm. Vekten ligger normalt på ca. 20-23 kg for en hanne, mens tispene gjerne veier 17-20 kg.
Tolleren skal gi et kraftfullt og kompakt inntrykk, uten å virke tung. Den er både mindre og lettere i kroppen enn de øvrige retrieverne, noe som gjør den smidigere og hurtigere enn disse.
Hodet er kileformet og er kortere og lettere enn for de andre retrieverrasene. Tolleren kan ha både mørkt pigment (sort) eller lyst pigment (kjøttfarget) på snute, lepper og øyelokkrender. Begge varianter er like aksepterte, men det er viktig at den fargen hunden har på snuten også skal gjenspeiles i lepper og øyelokkrender.
Pelsen er middels lang og består av en stri dekkpels (vannavstøtende) med tett og myk underpels. Beheng i brystet og på baksiden av frambena og bakbena. Halen er rikelig behåret og skal gi et tett og buskete inntrykk. Fargen varierer fra ganske lys oransje til mørk rød (mørkere over ryggen, mot noe lysere i buken) med hvite markeringer i brystet, på labbene (sokker), på hodet (bliss) og ytterst på halespissen. Brunrød farge, sorte hår i pelsen eller hvite markeringer på andre steder enn poter, bryst, hode og haletupp er særdeles uønsket.
Bruksområde
Tolleren er en meget utholdende og energisk hund, og en meget dyktig svømmer og apportør. Den er en allsidig brukshund med en rekke flotte egenskaper som gjør den velegnet for så å si alle hundesporter. For mange utgjør den dessuten en god og stødig familiehund, som også har vakthundegenskaper, men det må understrekes at tolleren ikke er avlet med tanke på vokting og det er store individuelle forskjeller når det gjelder vaktinstinkter.
Tollerens spesialitet er som rasenavnet tilsier såkalt tollingjakt/lokkejakt på ender og gjess, der den med sitt lekfulle vesen og bevegelsesmønster lokker viltet inn på skuddhold for så å apportere det fra vann eller land. Det er denne typen jakt som rasen er avlet fram for, men den kan også brukes til alt fra duejakt til storviltjakt (da hovedsakelig ettersøk).
Den er en særdeles god sporhund og rasen har hatt stor fremgang som ettersøkshund på skadet vilt, redningshund, m.m. Tolleren er dog meget allsidig, og egner seg også godt til f.eks. lydighet, agility, freestyle og andre aktiviteter.
Lynne og væremåte
Tolleren er en meget lojal og viljesterk hund som passer for aktive familier. Rasen kan være noe skeptisk til fremmede og er kjent for å varsle når slike kommer på besøk, men den er ingen utpreget vakthund.
Referanser
Eksterne lenker
Norsk Retrieverklubb
Hunderaser
Retrievere | norwegian_bokmål | 0.754641 |
dog_eyes_glow/eye-structure-and-function-in-dogs.txt | honeypot link
skip to main content
skip to main content
*
MSD MANUAL Veterinary Manual
VETERINARY CONTENT PET HEALTH RESOURCES QUIZZES ABOUT
1. Veterinary /
2. Dog Owners /
3. Eye Disorders of Dogs /
4. Eye Structure and Function in Dogs /
PET OWNER VERSION
# Eye Structure and Function in Dogs
By Kirk N. Gelatt , VMD, DACVO , Department of Small Animal Clinical
Sciences, College of Veterinary Medicine, University of Florida
Reviewed/Revised Jun 2018
View the Professional Version
* Physical Examination of the Eye |
* For More Information |
The eyes of animals, including dogs' eyes , function much like yours.
Animals also develop many of the same eye problems that people can have,
including cataracts, glaucoma, and other problems. It is important for your
dog to receive good eye care to protect its sight and allow it to interact
comfortably with its environment.
The eye is an active organ that constantly adjusts the amount of light it lets
in and focuses on objects near and far. It produces continuous images that are
quickly relayed to the brain.
###
Anatomy of the eye
---
The bony cavity or socket that contains the eyeball is called the orbit .
The orbit is a structure that is formed by several bones. The orbit also
contains muscles, nerves, blood vessels, and the structures that produce and
drain tears.
The white of the eye is called the sclera . This is the relatively tough
outer layer of the eye. It is covered by a thin membrane, called the
conjunctiva , located near the front of the eye. The conjunctiva runs to the
edge of the cornea and covers the inside of the eyelid. The cornea is a
clear dome on the front surface of the eye that lets light in. The cornea not
only protects the front of the eye, but also helps focus light on the retina
at the back of the eye. The iris is the circular, colored area of the eye.
It controls the amount of light that enters the eye by making the pupil larger
or smaller. The pupil is the black area in the middle of the eye. The pupil
is controlled by the circular sphincter muscle. When the environment is dark,
the pupil enlarges to let in more light; when the environment is bright, the
pupil becomes smaller to let in less light.
The lens , which sits behind the iris, changes its shape to focus light onto
the retina. Small muscles (ciliary muscles) contract to cause the lens to
become thicker, which allows the lens to focus on nearby objects. The ciliary
muscles relax to cause the lens to become thinner when it focuses on distant
objects. These lens changes are limited in dogs. The retina contains the
cells that sense light (photoreceptors). The most sensitive area of the retina
is called the area centralis in dogs; this area contains thousands of tightly
packed photoreceptors that make visual images sharp. Each photoreceptor is
attached to a nerve fiber. All the nerve fibers are bundled together to form
the optic nerve . The photoreceptors in the retina convert the image into
electrical impulses, which are carried to the brain by the optic nerve.
The upper and lower eyelids are thin folds of skin that can cover the eye and
reflexively blink to protect the eye. Blinking also helps spread tears over
the surface of the eye, keeping it moist and clearing away small particles.
The eyes of a dog are protected not only by the same types of eyelids that
people have, but also by the nictitating membrane , which is sometimes
called the third eyelid. This additional eyelid is a whitish pink color, and
it is found under the lower eyelids on the inside corner of the eye (near the
nose). The third eyelid extends across the eye when needed to protect the
eyeball from scratches (for example, while traveling through brush) or in
response to inflammation.
To function properly, eyes must be kept moist. Tears are the source of this
needed moisture. Tears are comprised of water, oil, and mucus. Lacrimal
glands produce the watery portion of tears. They are located at the top outer
edge of each eye. Mucus glands in the conjunctiva (called goblet cells)
produce mucus. Meibomian glands within the eyelids produce the oily portion.
The mixture of water, oil, and mucus creates a more protective tear that is
slower to evaporate. Nasolacrimal ducts allow tears to drain from each eye
into the nose. Each of these ducts has openings at the edge of the upper and
lower eyelids near the nose.
###
Structures that protect the eye, dog
---
## Physical Examination of the Eye
Because of the importance of sight to your dog, one of the critical aspects of
any examination or checkup will be an examination of your pet’s eyes. Be
prepared to provide any background or medical history (such as any previous
injury to the eye, history of treatments or medications used, any signs of
visual problems, and vaccination history) that might help with the diagnosis
of any eye problem.
The first step of the examination involves checking to be sure that the shape
and outline of the eyes are normal and that there are no obvious
abnormalities. Then, using light and magnification in a darkened room, the
reflexes of the pupils and the front part of the eye are examined. Depending
on these findings and the reasons for the checkup, additional tests may be
needed. Some parts of the examination may require sedation or anesthesia.
A test, called the Schirmer tear test, may be performed to ensure that the
eyes are producing enough tears to keep them moist. This is a relatively
simple test in which a small paper strip is inserted under the eyelid to
measure the amount of moisture produced. Another common test involves placing
a small drop of fluorescein stain into each eye, which allows defects—such as
scratches in the cornea of the eye—to be detected.
Pressure within the eye is measured painlessly using an instrument called a
tonometer. (If eye pressure is too high, optic nerve damage can occur, leading
to irreversible blindness.) A swab may also be done to culture for bacteria or
fungi. The eyelids may be turned inside out to examine the underside. The
nasolacrimal tear duct may be flushed to evaluate the external parts of the
eye. Drops may be added to the eyes to allow the pupils to become dilated so
that the veterinarian may examine the internal parts of the eye using an
ophthalmoscope.
## For More Information
Also see professional content regarding eye structure, function, and physical
examination .
Test your Knowledge now Take a Quiz!
* About
* Disclaimer
* Cookie Preferences
*
*
Copyright © 2024 Merck & Co., Inc., Rahway, NJ, USA and its affiliates. All
rights reserved.
| biology | 14911 | https://no.wikipedia.org/wiki/%C3%98ye | Øye | Øye (lat. oculus) er en biologisk innretning, som projiserer lys via en linse på synsnerver i netthinnen og omsetter signalene til impulser i synsnervene. Synsnervene videresender informasjoner om lyset til hjernens occipitallapper, som fortolker disse, og skaper et bilde.
Menneskets øye
Øyeeplet (lat. bulbus oculi)
Øyeeplet er kuleformet og inneholder brytende medier som fokuserer lyset på netthinnen. Sanseceller i netthinnen omdanner lyset til nervesignaler.
Hornhinnen
Hornhinnen (lat. cornea) ligger fremste på øyeeplet når øyelokkene er åpne. Hornhinnen er blank og klart gjennomsiktig. Den har et større antall lag som særlig kan sees ved bruk av spaltelampe.
Det ytterste laget av hornhinnen består av et cellelag som er en celle tykt. Sår i dette cellelaget oppstår ved fremmedlegeme på øyet, solblindhet, sveiseblink og enkelte virusinfeksjoner. Slike sår kan bli synlige ved å dryppe fargestoffet fluorescein på øyet. Fargestoffet er gult, men ved kontakt med hornhinnen under cellelaget, blir fargen grønn.
(se også hornhinnebetennelse)
Regnbuehinne
Regnbuehinnen eller iris, er den fargede delen av øyet hos virveldyr, inkludert mennesker. Regnbuehinnen har et hull, pupillen, i midten og muskler som gjør at pupillens størrelse kan justeres etter lysintensiteten.
Pupillen
Pupillen er hullet midt i regnbuehinnen. Hullet eller pupillens størrelse justeres med muskler i regnbuehinnen. Størrelsen endres basert på mengde lys mot øyet. Gjennom pupillen slippes lyset inn i det indre øyet.
Linsen befinner seg rett bak pupillen, i øyets lysåpning. Her blir lyset som utgjør det visuelle inntrykket vi oppfatter som det endelige bildet, snudd før det når netthinnen.
Netthinnen
Netthinnen (retina) fanger opp synsinntrykk og ligger som et bakteppe innvendig i øyet. Den består av celler utformet som tapper og staver. Tappene er med på å oppfatte farger og gir et skarpt syn. Stavene gir svart-hvitt-syn og syn i mørke. Netthinnen kan reflekte lys tilbake som rød refleks (se nedenfor), som hos katter og mange andre pattedyr.
I tillegg til det visuelle systemets tapper og staver, er det lys-sensitive ganglier som registrer lysstyrke og -farge - selv hos mange totalt blinde mennesker som har minst ett øyeeple intakt. Lyset som registreres av disse cellene er det sterkeste av signalene som styrer døgnrytmen.
Synsnerven forlater netthinnen ved den blinde flekk. Skarpsynet i netthinnen er lokalisert til den gule flekk (macula lutea), hvor det er særlig høy tetthet av tapper og staver.
Orbita
Øyehulen.
Er større enn bulbus oculi, som gir plass til de ytre øyemusklene, tallrike årer og nerver, samt tårekjertelen.
Gulvet i orbita grenser mot sinus maxillaris (kjevebihulen), taket mot sinus frontalis (pannebihulen) og kraniehulen. Bakveggen, som ligger i høyde med øvre del av hjernestammen, har åpninger til årer og nerver.
De seks ytre øyemusklene beveger bulbus oculi. Tverrstripet muskelfibre. Øyemusklene er synkronisert og jobber sammen, bortsett fra når vi studerer noe som er svært nært.
Her er de listet opp i forhold til hvilken nerve som forsyner dem:
Nervus oculomotorius
Musculus rectus superior – drar øyet oppover
Musculus rectus inferior – drar øyet nedover
Musculus rectus medialis – drar øyet innover
Musculus obliquus inferior – roterer øyet utover og drar det litt oppover
Nervus trochlearis
Musculus obliquus superior – roterer øyet innover og drar det litt nedover
Nervus abducens
Musculus rectus lateralis – drar øyet mot siden
Arteria ophtalmica går fra arteria carotis interna og deler seg til en rekke mindre grener som forsyner ulike deler i orbita. Den viktigste grenen er arteria centralis retinae, som følger nervus opticus inn i bulbus oculi til retina, og er hovedansvarlig for blod til fotoreseptorene.
Nervus opticus (2. hjernenerve)leder afferente signaler fra fotoreseptorene
Nervus oculomotorius (3. hjernenerve) leder efferente signaler til tverrstripet og glatt muskulatur – styrer øyemotorikken.
Bulbus oculi beskyttes mekanisk av øyelokk og øyevipper. Lokkene inneholder stive plater av bindevev, kantene har en rand av hår og utallige kjertelåpninger. En muskel sørger for at øyet kan åpnes, mens ringformet muskelfiber sørger for at øyet kan forsnevres/lukkes. Innsiden er kledd med conjuctiva(tårehinnen) som slår seg over på sclera og dekker denne helt inn mot cornea.
Tårekjertelen ligger diagonalt over på andre siden av tårekanalene og produserer tårevæske som smører og renser hornhinnen cornea. Irritasjon eller rusk fører til økt produksjon. Tårekanalene drenerer tårevæske til nesehulen
Disse styres av parasympatiske nervefibre – det er ingen viljemessig kontroll over produksjonen, men den kan påvirkes av emosjonelle forhold.
Den blinde flekk
En annen test går ut på å lukke det ene øyet og holde en liten lys gjenstand et stykke rett foran det åpne øyet. Stirr på et punkt bak gjenstanden, og før den lyse gjenstanden ut til siden/samme side som det åpne øyet. Ca 15-20 grader ut til siden sees plutselig ikke den lyse gjenstanden. Bildet av den har truffet netthinnen på den blinde flekk.
Rød refleks
Når lys fra ett punkt i et ellers mørkt rom treffer et øye med stor pupill, vil lyset som samles på netthinnen også sendes tilbake, slik at hvis vi ser på øyet fra nesten samme retning som lyset kommer fra, vil vi se et rødt lys der vi vanligvis ser det sorte i pupillen i midten av øyet.
Dette brukes til undersøkelser på helsestasjonen for å utelukke en sjelden kreftsykdom på netthinnen. Ved katarakt (grå stær), når øyets linse blir matt, vil vi ikke se rød refleks. Ved en del tilstander med puss eller uklarheter i øyets væske vil også rød refleks bli borte.
Når vi kjører bil i mørke kan vi se dyr på langt hold som små lyspunkter som er rød refleks fra øynene.
Senehinne og konjunktiva
Øyeeplet er kledd av en senehinne (lat. sclera) som musklene (se under) festes i. Senehinnen dekker hele øyeeplet bortsett fra hornhinnen, som må være gjennomsiktig.
Over den delen av senehinnen som ligger eksponert for luft ligger konjunktiva, som er et hudlag med blodårer og nerver. Konjunktiva dekker også innsiden av øyelokkene.
(Se også konjunktivitt.)
Menneskets øye i kunst, litteratur og filosofi
Det blir av noen hevdet at «Øynene er sjelens speil» og at de kan utvise frykt, glede, sorg, tristhet, tankefullhet, hat, hevn og ondskap.
De meste berømte øyne i billedkunsten er trolig øynene til Mona Lisa, portrettet Leonardo da Vinci malte.
Øyet hos virveldyr
Virveldyr har primært minst tre øyne, et på hver side fremme på neurokraniet, samt et såkalt panneøye eller parietaløye/pinealøye midt i pannen. Dette er fremdeles synlig som et lysfølsomt organ blant flere arter innen alle virveldyrklasser, med unntak av fugler og pattedyr hvor det uten unntak, er modifisert til en kjertel kalt pinealkjertelen.
Øyet hos pattedyr
Øyet hos andre pattedyr har en lik oppbygning som øyet hos mennesket, det er kulerundt og har samme anatomi. Noen pattedyr har bedre syn enn mennesket, særlig det å se når det er svakt lys, nattsyn.
Øyet hos fugler
Øyet hos fuglene har i motsetning til øyet hos pattedyr ikke en rund form, men er forstørret og avflatet inne i hodet, som en omvendt trakt. Dette gir mindre bevegelsesfrihet, men desto bedre syn. En ring av små bein rundt hvert øye gir feste for øyemuskler.
Fugleøyet ser ut til å være det best utviklete av alle virveldyrøyne. Selv om de er utstyrt med både et øvre og et nedre øyelokk, benytter de fleste en blinkhinne ved blunking. Blinkhinnen beskytter øyet under flyging, og fungerer både som solbriller og beskyttelse mot vær og vind. Hos dykkende fugler kan den til og med brukes som dykkerbriller som bidrar til skarpt syn under vann, i tillegg til at disse fuglene ofte har en svært fleksibel linse som kan krummes nok til å se skarpt både i vann og i luft.
Ugler er en av de få gruppene som blunker på samme måte som pattedyr. Fugler har er to fovea på netthinnen, i motsetning til mennesket, som bare har en. Dagaktive fugler kan dessuten oppfatte ultrafiolett og polarisert lys.
Øyet hos fisker
Øynene til slimåler er rudimentære og mangler linse. At noen av artene har mer utviklete øyne enn andre forteller at de dårlig utviklete øynene er en sekundær egenskap og en tilpasning til de mørke havdypene hvor de holder til.
Øyet hos virvelløse dyr
Leddyr
Leddyr er en stor dyregruppe med mange, svært ulike arter, derfor er det variasjon i hvordan øynene er utformet. Generelt er det to slags øyne i denne dyregruppen. Fasettøyne og punktøye eller medianøye.
Fasettøye, er et sammensatt øye som består av flere enkelt øyne (ommatidier) i en gruppe, ett «stort øye». Hvert slikt enkelt øye er sekskantet. Slike øyne er vanlig hos de fleste leddyr og forekommer hos de fleste insekter, krepsdyr, mangefotinger, dolkhaler og også i den fossile gruppen trilobitter. Enkelte arter kan ha fasettøyne med bare noen få øyne, eller fasetter. Men et fasettøye kan også bestå av opp til små sekskantete fasetter. Øynene er enten hårløse eller besatt av mengder av små korte rett utstående hår, mellom fasettene. Fasettene øverst på øyet kan hos noen arter være større enn fasettene nederst.
Punktøyne / medianøyne (ocellus) er en type enkelt øyne. Punktøyne oppfatter bare lys eller mørke. De brukes derfor ikke til å se med, men mer som ekstraøyne. Mange leddyr har slike punkøyne oppe på hodet eller i pannen. Ofte er det tre punktøyer – som danner en trekant.
Bildegalleri
Se også
Syn
Blindhet
Eksterne lenker
Øyet: Derfor blir synet dårligere etter 40
1000 artikler enhver Wikipedia bør ha | norwegian_bokmål | 0.533658 |
dog_eyes_glow/dog-eye-anatomy.txt | Skip to content
* About Us
* How it works
* What we stand for
* Our Founders
* Our experts
* News
* Endorsements
* Research
Menu
* About Us
* How it works
* What we stand for
* Our Founders
* Our experts
* News
* Endorsements
* Research
* Zigzag App: Puppy Training Made Easy
* About Us
* How it works
* What we stand for
* Our Founders
* Experts
* Endorsements
* News
* Research
* Blog
* Contact
* *
Menu
* Zigzag App: Puppy Training Made Easy
* About Us
* How it works
* What we stand for
* Our Founders
* Experts
* Endorsements
* News
* Research
* Blog
* Contact
* *
* Blog
* Contact
Menu
* Blog
* Contact
Download now
Download
* *
* *
# Dogs Eye Anatomy : Everything You Need To Know
#### By Zigzag Puppy Expert, Petrina Firth
Fully Qualified COAPE Behaviourist and Registered Training Instructor with The
Animal Behaviour and Training Council
#### In this article:
We’re not exaggerating – dogs’ eyes are a marvel of engineering. Their eyes
allow them to see the way in the incredible way they do. Puppy eyes are much
like our own eyes. They have a lot of components, although they work
differently. In fact, in some aspects, dogs’ eyes are far superior to ours;
they have a broader field of vision and can detect movement far better.
In this article, we’ll keep your eyes peeled as we take a look at the anatomy
of dogs’ eyes. We’ll go over how puppy eyes work, and answer all kinds of
questions like how can dogs see in the dark, can dogs see colour, can dogs
watch TV, and what colours dogs see best. We bet you’re dying to know.
Check out the Zigzag puppy training app for more information on your puppy’s
development, and learn much more about how they see the world. We’ve also got
a team of top-class dog trainers and behaviourists to answer your questions.
They’ll keep a (human) eye on you throughout your journey through puppyhood
too.
Photo by Jesse Collins on Unsplash
## What is the anatomy of dogs’ eyes?
Dog eyes are made up of a cornea, iris, pupil, lens, retina, and sclera. They
also have an upper and lower eyelid and a third eyelid on the outside of the
eye for protection. Rods and cones are how images and light are processed and
important for vision.
Let’s take a closer look at how each of these works.
### Cornea
The transparent dome-like structure that covers the front of the eye. It bends
light as it enters the eye.
### Iris
This is the coloured part of a dog’s eye. It’s the bit that makes them
beautiful, essentially. It can be yellow, brown, blue or even white, which
expands and contracts in low light or bright light.
### Pupil
According to light intensity, the pupil opens and closes.
### Lens
The lens focuses light into the retina
### Retina
This transforms light signals into the optic nerve and off into the brain.
### Sclera
This is the white part of the eye that surrounds the iris.
### Eyelids
Dogs have three eyelids: an upper, a lower and then a third eyelid. They
mainly serve to protect the eye, the third eyelid sweeping back and forth to
spread tear film and keep the eye moisturised.
### Rods and Cones
There are photoreceptors found in the retina, these process light signals.
Cones allow dogs to see colours, while rods allow them to see shapes.
## How do puppy eyes work?
Puppies are born with their eyelids closed because their eyes are not fully
developed. It’s actually quite endearing. Because their eyes are still
developing for the first two weeks, their eyelids remain closed to protect
them. Puppy eyes open around 14 days and usually one at a time.
Puppies do quite alright without their eyes being open at the start actually,
they don’t need their vision much as newborns. All they need is to find their
mother for milk, and they mainly rely on their sense of smell for this. When
they first open their eyes, their vision will be poor, and their eyes will
look grey or blueish and a little milky. As the weeks go by, their eyesight
develops more, and they’ll start seeing more clearly and start recognising
shapes better. Puppy eyes reach full development at around 8 weeks of age.
Once developed, their eyes will work the same way as dogs’ eyes do. Light goes
into the eye through the cornea, and is focused onto the lens by the pupil at
the centre of the iris. The lens bounces the light around, and then focuses
light onto the retina, which sends a signal through the optic nerve into the
brain.
But it’s really the rods and cones who control how puppies see. Rods are
light-sensitive and are used for shape and motion perception; dogs have far
more rods than humans do. Cones are what control colour perception, and are
the responsible ones for the reputation of dogs being colourblind, as they
only have around 20% of the cones that humans do.
But in reality, puppies are no different in that the spectrum of colour they
see is different to that of a human. Instead of seeing a full array of
colours, they see things in a yellow-blue spectrum. Despite not being able to
see a full spectrum of colour, puppy eyes are much more sensitive than ours at
night, and they also have an excellent movement-activated vision. This is an
evolutionary characteristic that would have been extremely useful for hunting
and they retained it after domestication .
Photo by Izabelly Marques on Unsplash
## Can dogs see in the dark?
Well…kinda! Our dogs’ wild ancestors were crepuscular, meaning that they
hunted at dawn and dusk. Dogs, as we know them today, have kept this
interesting talent. Their ability to see in the dark is made possible due to a
reflective system called the tapetum lucidum (easily confused with a Harry
Potter spell), which sits behind the retina and helps to enhance visual
sensitivity at low light levels.
Dogs have light-sensitive rods in their eyes, which help them detect movement
and light in low-light conditions. However, when it’s pitch black dogs will
struggle to see as well as us, and will rely on their other powerful senses
like their sense of smell to move around.
## Can dogs see colour?
Dogs see in certain colours, but not all. While humans see the entire colour
spectrum in trichromatic vision, dogs have a dichromatic vision and only see
blue/yellow, plus shades of grey and brown. This is because we have three
types of cones in our eyes, and dogs only have two.
Dogs also only have around 20% of the cones that humans do, meaning that the
colours they do see are more muted, whereas humans see the world in more vivid
and bright colours.
## What colours do dogs see best?
Dogs have dichromatic vision, which means that their eyes can best see the
colours yellow and blue, along with combinations of the two. Blue, blue-green,
and violet are all different shades of blue to a dog, and shades of red and
green are likely to appear as browns and grayscale.
This is the same across all breeds. They all have the same colour vision,
although different breeds, due to their skull shape and eye position, will
have better eyesight in terms of depth perception than others.
This may help you figure out what colour toys to buy your dog, blue and
yellow are definitely best as they’ll be able to find them and see them
easily.
Photo by Mathis Jrdl on Unsplash
## How to care for my dog’s eyes?
Puppy eyes should be cleaned as part of a regular grooming routine , and the
sooner you start, the better. You want them to get used to grooming when
they’re young so you don’t face any hiccups when they’re older. Check your
dog’s eyes daily, and wipe away any dirt or debris with a clean cotton pad.
Some dogs will wake up with weird eye snot. Don’t rub their actual eyeballs,
by the way! Just wipe away any dirt around them and on the corner, where it
tends to accumulate.
You shouldn’t need to use any harsh chemicals or specific cleaners for this,
just cooled boiled water on a cotton pad is all you need to clean the eyes
fully. If your dog’s eyes are runny , inflamed or bloodshot , you should
see a vet instead of diagnosing them at home with eye drops. Dogs’ eyes are
precious, so it’s worth taking care of them!
Different breeds of dogs, such as Pugs and French Bulldogs , will likely
need more care and attention paid to their eyes. Due to their flat faces, they
have a higher risk of gunk getting in, because their eyes stick out more. They
also have a lot of skin around their eyes, which can lead to eye problems like
cherry eye , and also are more prone to ulcers. We love our little aliens,
and keeping an eye will help make sure they actually keep their eyes. Hmm…too
dark?
We hope this has given you a good overview of how dogs and puppies see the
world. We’ve covered how dogs see best in blue and yellow, and how you should
use those colours for any toys you choose to treat them with. We’re sure
you’re well-equipped to take care of your dog’s eyes well, but your vet will
always be happy to help you if you notice any redness or soreness in the eye.
Now that you’re here, why not read our guide all about how to brush your
puppy’s teeth ? You’ll need to know what toothbrush and toothpaste to get
for their dashing smile too, so be sure to check it out.
Download the Zigzag app , and find much more helpful information on how to
take care of your puppy, including grooming, and that step-by-step training
programme you’ve been looking for all this time. We even have breed-specific
training guides to give your puppy the best start and a team of professional
trainers and behaviourists on hand to talk to, whenever you run into some
trouble.
#### By Petrina Firth, Zigzag Puppy Expert
Fully Qualified COAPE Behaviourist and Registered Training Instructor with The
Animal Behaviour and Training Council
#### In this article:
#### Zigzag App
### Fun & Easy Puppy Training App
* Personal training schedule based on age & breed
* 24/7 Puppy expert coaching for pawnic moments
* 3-5 Daily dog exercises
## Have a pup they said.
It will be fun they said.
#### We go the extra mile for you. That's why people say this:
5/5
#### Excellent app for new puppy owners
“It takes you through training step by step plus you can join the community of
others owners where you can share ideas and advice. 5 star”
– Sian Davies (in Google Playstore)
5/5
#### INCREDIBLE for Humans and Puppies!
“I downloaded this app whilst trying out different apps and none came anywhere
near close to the level of support I received with ZigZag! The WhatsApp
service has been a godsend with our new puppy and I can’t even imagine having
survived the first few days without it! If you want a stress free puppy
experience, get this downloaded! Worth every single penny!”
– Marta Biscotto 🇬🇧 (via App Store)
5/5
#### Excellent. This app is very helpful.
“It covers everything you need when in the storm that is new puppy land!! It
helps you to understand and gives you a path to follow. The coaching support
is excellent and super speedy. Don’t know what I would have done without it.”
– Started 🇬🇧 (via App Store)
## Let's embark on your journey to pup happiness.
### Download the app now
### Your journey to pup happiness.
Facebook-f Twitter Linkedin-in Instagram Tiktok Link At
### Sign up to our newsletter
#### All about Zigzag
* Home
* What makes us unique?
* App Features
* About Us
* Contact
* Terms and Conditions
* Privacy Policy
* Cookie Notice
* Home
* What makes us unique?
* App Features
* About Us
* Contact
* Terms and Conditions
* Privacy Policy
* Cookie Notice
©2024 Zigzag Petcare Services Ltd
Cookie & Ad Settings | Sitemap
* *
##### Cookie & Ad Settings: Preference Centre
We use cookies to give you the best online experience. Cookies keep our site
secure and reliable. They let us personalise zigzag.dog to you (and your dog)
and help us to analyse how the site is used. By clicking "Accept All", you
consent to the use of ALL the cookies. See full Cookie Policy .
Cookie & Ad Settings Accept all Optional Cookies Reject All
Cookie & Ad Settings
Close
#### Cookie & Ad Settings: Preference Centre
We collect personal information about users over time and across different
websites when you use this website or service. We also have third parties that
collect personal information this way. To do this, we use several common
tracking tools. These may include browser cookies. We may also use web
beacons, flash cookies, and similar technologies. We use these tools as
described in our Privacy Policy .
Read below to learn more about the different types of cookies we use and how
to change your settings. Blocking some types of cookies may impact your
experience on the site. Cookies are currently disabled which means these
cookies cannot be used. To turn these cookies on, toggle the button. “Enabled”
means these cookies can be used.
Necessary
Necessary
Always Enabled
Necessary cookies are absolutely essential for the website to function properly. These cookies ensure basic functionalities and security features of the website, anonymously. Cookie | Duration | Description
---|---|---
cookielawinfo-checkbox-analytics | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Analytics".
cookielawinfo-checkbox-functional | 11 months | The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional".
cookielawinfo-checkbox-necessary | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookies is used to store the user consent for the cookies in the category "Necessary".
cookielawinfo-checkbox-others | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Other.
cookielawinfo-checkbox-performance | 11 months | This cookie is set by GDPR Cookie Consent plugin. The cookie is used to store the user consent for the cookies in the category "Performance".
viewed_cookie_policy | 11 months | The cookie is set by the GDPR Cookie Consent plugin and is used to store whether or not user has consented to the use of cookies. It does not store any personal data.
Functional
Functional
Functional cookies help to perform certain functionalities like sharing the
content of the website on social media platforms, collect feedbacks, and other
third-party features.
Performance
Performance
Performance cookies are used to understand and analyze the key performance
indexes of the website which helps in delivering a better user experience for
the visitors.
Analytics
Analytics
Analytical cookies are used to understand how visitors interact with the
website. These cookies help provide information on metrics the number of
visitors, bounce rate, traffic source, etc.
Advertisement
Advertisement
Advertisement cookies are used to provide visitors with relevant ads and
marketing campaigns. These cookies track visitors across websites and collect
information to provide customized ads.
Others
Others
Other uncategorized cookies are those that are being analyzed and have not
been classified into a category as yet.
SAVE & ACCEPT
### Zigzag Puppy Coach
#1 Puppy Training App
Install
## Be first in line!
Just like you – we’re also training to get better. Therefore, we can’t let
everybody in at once. Sign up below and we’ll let you know when there’s a
spot available for you.
Email
Yes, I want in!
| biology | 429273 | https://da.wikipedia.org/wiki/Staffordshire%20Bull%20Terrier | Staffordshire Bull Terrier | Staffordshire Bull Terrier ("Staffy'en") er en hunderace, der stammer fra Staffordshire i Storbritannien. De første eksemplarer af racen blev indregistreret i England i 1935, hvilket er 100 år efter at hundekamp blev forbudt. Racen er derfor udelukkende skabt som familiehund og udstillingshund. Racen blev i 2006 kåret til årets familiehund i England. Staffordshire bull terrier stammer formodentlig fra datidens bulldogracer og terrierracer, med vægt på bulldogracerne. I det berømte Staffordshire Regiment, er staffordshire bull terrier regimentsmaskot. Efter 2. verdenskrig blev det tradition, at regimentet ved parader havde en staffordshire bull terrier til at gå forrest.
Den har et bredt hoved, med kort snudeparti og rosen-ører (ørekupering er ikke tilladt i Danmark), stærke kæber og øjne placeret så blikket er fremefter. Den har korte ben og en middel-lang hale, bredt bagparti og brede skuldre.
Temperament
Staffordshire Bull Terrier er loyal og hengiven overfor sin familie, og er særligt velfungerende med børn. Den trives med familielivet og nyder at dase i sofaen såvel som at gå lange ture. Den er energisk og evigt begejstret, uanset hvad den laver. Den er venlig af sind, følsom og intelligent.
Racen er frygtløs og nysgerrig på alt omkring den. Det er skønt i hverdagen, men det kan også betyde at ejeren skal tænke på vegne af hunden. Ser en Staffordshire noget spændende i horisonten, så tænker den ikke over om den springer 2 meter ned fra en altan eller løber ud over en vej. Derfor er det også vigtigt at træne en Staffordshire Bull Terriers impulskontrol. Den er uegnet som vagthund, og selvom den godt kan sige vov, når der kommer gæster, så er den generelt utroligt venlig overfor fremmede. Mange har oplevet indbrud, hvor overvågningen har vidst Staffordshire Bull Terrieren slikke og ville lege med tyven.
Efter kønsmodning kan nogle Staffordshire Bull Terriers godt være mindre sociale og legesyge overfor fremmede hunde, og særligt hunde af samme køn som dem selv. Ligesom med alt andet socialisering og træning, er det vigtigt at man som ejer præger sin hund på en positiv måde, og bidrager til at få en velafbalanceret hund.
Aktivitetsniveau
En Staffordshire Bull Terrier er en aktiv race. De er nysgerrige og har brug for at få tilfredsstillet deres nysgerrighed og fysiske behov for aktivitet. Et par gåture rundt i villakvarteret hver dag er sjældent tilstrækkeligt. Den vil gerne træne og den vil gerne ud på tur. Løbeture eller lange gåture i skoven vil være en stor glæde for racen. Racen er ikke altid god til at komme af med varmen om sommeren, derfor skal man være opmærksom på ikke at motionere når det er varmest, og sørge for at hjælpe hunden med at køle ned ved at give den rigeligt væske og eventuelt et køledækken. Tag gerne en drikkedunk med på gåturene. Da hunden er stærk og har utroligt meget energi, vil den oftest lege langt tid længere end man lige forestiller sig - og hvad den kan holde til. Derfor er det vigtigt at du sætter restriktioner på aktiviteten, selvom hunden virker glad for at leget i det uendelige, da det kan fremprovokere stress.
Pelspleje
Den helt korte og glatte pels har ingen underuld. Det betyder også, at den er dårlig til at holde på varmen om vinteren. Derfor er racen kuldskær og et lunt dækken vil være en fordel i vinterperioden. Pelsen er let at holde, og kan tørres af med et opvredet vaskeskind, for at fjerne eventuelle løse hår.
Træning
Det er en intelligent race, der gerne vil samarbejde og træne med sin fører. Den kan være stædig, så god tålmodighed og gode belønninger, samt generel positiv indlæring anbefales. Du får de bedste resultater med positiv forstærkning, og Staffordshire Bull Terrieren kan klare sig godt i forskellige hundesportsgrene som lydighed, rally, nosework og agility.
Den er særdeles glad for at lege, både med sine mennesker og med andre hunde. Derfor er legetøj i træning en en stor fordel, og en motivationsfaktor. Da racen kan have tendens til at stresse, og have dårlig impulskontrol, vil det være en god idé at træne nedstressning og passivitetstræning. Dette gøres bedst ved at lege af kortere varighed, og rose hunden for at optræde roligt imellem legene.
Farver og fysik
Rød, fawn (lysebrun), hvid, sort, brindle (tigerstribet) eller blå. Alle aftegn kan være med hvide aftegninger.
Højde: 35,5 cm - 40,5 cm
Vægt hanner: 13-17 kg.
Vægt tæver: 11-15 kg.
Foder
Når du vælger foder til din staffordshire bull terrier, er det vigtigt at du vælger et foder der dækker alle dens behov. Det er særlig vigtigt at hvalpen fodres korrekt det første år, da det har stor betydning for om den eventuelt udvikler ledsygdomme. Da racen kan være disponeret for hudproblemer, er det vigtigt at du er opmærksom på dette og giver et foder, der understøtter en sund hud.
Er du i tvivl om, hvilket foder din hund skal have og hvilken mængde, så kan du altid spørge din dyrlæge til råds.
Referencer
Eksterne henvisninger
Terriere
Hunderacer fra England | danish | 0.928583 |
dog_eyes_glow/55-a-guide-to-common-eye-problems.txt | Please click here for the latest information on how to access our services.
CLINIC CONTACT NUMBERS
* Brighouse: 01484 404400
* Denby Dale: 01484 865845
* Dewsbury: 01924 465592
* Mirfield: 01924 492155
* Penistone: 01226 764764
* Sandal: 01924 258833
* Wakefield: 01924 372017
* Waterloo: 01484 469184
X
Menu
24hr Emergency Vets 01924 465592
Book an Appointment Register your Pet
Search
Search
* Home
* About Us
* Our Clinics
* Careers
* Graduate Development Programme
* Offers
* Development programmes
* RVN Training
* EMS Programme
* Sustainability
* Antibiotics Resistance Fact Sheet
* Reviews
* Cat Friendly Clinic
* Procedures & Pricing
* Our Services
* Facilities
* Ultrasound
* 24 Hour Emergency Service
* Dentistry
* Cat Dental Care in Dewsbury and West Yorkshire
* Dog Dental Care in Dewsbury and West Yorkshire
* Rabbit Dental Care in Dewsbury and West Yorkshire
* Cryopen
* Bereavement Room
* Video Consultation Service
* Repeat Prescriptions
* Consultations
* Flea and Worm Treatment
* Tick, Flea, and Worm Prevention for Cats
* Tick, Flea, and Worm Prevention for Dogs
* Microchipping
* Vaccinations
* Dog Vaccinations
* Cat Vaccinations
* Rabbit Vaccinations
* Neutering
* Annual Health Check
* Veterinary Nurse Clinics
* Pet Weight Management
* Weight management for your Cat
* Weight management for your Dog
* Weight management for your Rabbit
* Senior Pets
* Senior Pets Wellness Clinic
* Pet Health for Life Plan for Rabbits
* Laparoscopic spay
* Rehabilitation Centre
* Pet Health for Life
* Cat Pet Health for Life Plan
* Dog Pet Health for Life Plan
* Rehabilitation Centre
* Pet Hydrotherapy
* Physiotherapy
* Laser Treatment
* Meet the Team
* Pet Owners
* Find Your Nearest Clinic
* Help & Advice
* Dogs
* Dietary Advice
* Behaviour
* Puppy Advice
* Physiotherapy
* Neutering
* Eye Care
* Medication
* Vaccinations
* Senior Dogs
* Dental Advice
* Parasites
* Ear Conditions
* Skin Care
* Cats
* Kitten Advice
* Neutering & Microchipping
* Medication
* Eye Care
* Dietary Advice
* Senior Cats
* Vaccinations
* Behaviour
* Dental Advice
* Parasites
* Rabbits
* Dietary Advice
* Young Rabbits
* Senior Rabbits
* Rabbit Flystrike
* Rabbit Calcivirus
* General Pet Advice
* Pet FAQ's
* Pet Health
* Veterinary Procedures
* Pet Travel
* Pet Boarding
* Case Studies
* Advice for Pet Owners and COVID-19 (Coronavirus)
* News
* Contact Us
* Book an Appointment
* Register Your Pet
* Lost and found pets
* Our Services
* * Home
* Help & Advice
* Dogs
* Eye Care
* A guide to common eye problems
# A guide to common eye problems
A healthy dog's eyes should be clear, bright, and free from dirt, discharge,
and inflammation. However, it is quite common for dog eye problems to occur,
here is a guide of how to spot eye problems in your dog and how to provide
treatment.
## Looking After Your Dog's Eyes
### Common Eye Conditions and Symptoms
* Keratoconjunctivitis Sicca (Dry Eye) - This occurs when your dog's tear glands do not produce enough tears, resulting in recurrent or chronic conjunctivitis and persistently sore eyes. If left untreated, this condition can even lead to blindness. Though all dogs are susceptible, certain breeds, such as West Highland Terriers, Cavalier King Charles Spaniels, and Cocker Spaniels, seem to be more prone to this problem.
* Conjunctivitis - An inflammation of the membrane that covers both the inner lining of the eyelid and the white of the eye. It can be caused by infections, allergies, inadequate tear production, or irritation.
* Corneal Ulceration - This can occur when the shiny surface of the cornea is scratched or damaged.
* Epiphora - If your dog's eyes constantly "weep", or if the fur around them appears "stained", then the normal tear flow may be blocked, and you should contact your vet immediately.
* Cataracts and Glaucoma \- Dogs are just as susceptible to these conditions as humans. Cataracts cloud the lens inside the eye, and are the most common cause of blindness in dogs. A hereditary condition in some breeds, early examination by your vet is vital, as such animals should not be bred. Glaucoma stems from too much pressure being exerted upon the eye's interior as a result of a decrease in the amount of fluid draining from it.
### Common Symptoms of Illness
* Red inner eyelids
* Matter on the surface or in the corner of the eye
* Cloudiness within the eyeball
* A dull eye surface
* The "third eyelid" coming across the eye surface
* Excessive tearing or unusual discharges
* Tear-stained fur around the eyes
### Eye Tests to Help Diagnose Problems
* Fluorescein helps to identify corneal ulcers
* Schirmer Tear Test determines the level of tear production
* Ocular pressure is used to detect glaucoma
* Ophthalmoscopes can be used to see inside the eye chamber
### How To Treat Canine Eye Problems
Many canine eye problems can be treated at home with regular administration of
eye drops or ointment. When diagnosing treatment, our vets will tell you
everything you need to know about applying the drops or ointment, and about
dosages. But for ease of reference, we've prepared this handy guide.
### How To Administer Eye Drops
* You may need to muzzle your dog
* Remove any discharge from around the eye with a cotton ball moistened with warm water
* Read the instructions on the bottle for dosage information, and shake if necessary
* Use one hand to hold the bottle between your thumb and index finger, and place the other under your dog's jaw to support their head
* Tilt their head back, and to prevent blinking, use your free fingers to hold the eyelids open
* Hold the bottle of drops close to the eye, but don't touch the eye's surface
* Squeeze the drops onto the eye, and once they're in, release the head
* Your dog will blink, spreading the medication across the eye's surface
### How To Administer Eye Ointment
* You may need to muzzle your dog
* Remove any discharge from around the eye with a cotton ball moistened with warm water
* Read the instructions on the tube for dosage information
* Gently pull back the upper and lower eyelids
* Hold the tube parallel to the lower eyelid, and squeeze the ointment onto the edge of the eyelid
* Massage the upper and lower eyelids together to spread the medication
* Release your dog's head and allow them to blink, further spreading the medication across the eye's surface
If you have any questions or concerns about your dogs eyes, contact your local
Calder Vets branch, we're always here to help.
Pet Advice Categories
* Dogs
* Dietary Advice
* Behaviour
* Puppy Advice
* Physiotherapy
* Neutering
* Eye Care
* Medication
* Vaccinations
* Senior Dogs
* Dental Advice
* Parasites
* Ear Conditions
* Skin Care
* Cats
* Kitten Advice
* Neutering & Microchipping
* Medication
* Eye Care
* Dietary Advice
* Senior Cats
* Vaccinations
* Behaviour
* Dental Advice
* Parasites
* Rabbits
* Dietary Advice
* Young Rabbits
* Senior Rabbits
* Rabbit Flystrike
* Rabbit Calcivirus
* General Pet Advice
* Pet FAQ's
* Pet Health
* Veterinary Procedures
* Pet Travel
* Pet Boarding
* Case Studies
* Advice for Pet Owners and COVID-19 (Coronavirus)
* See our Offers
* Join Pet Health for Life
* Book Appointment
Calder Vets is a multi clinic vets practice with 9 clinics in South and West
Yorkshire. When you search for 'vet near me' you will find a convenient Calder
vets ready to help.
Click here to find your local vets
* Home
* About Us
* Our Services
* Pet Health for Life
* Pet Owners
* Help & Advice
* News
* Contact Us
Select your local Calder Vets clinic:
* Brighouse Vets
* Denby Dale Vets
* Dewsbury Vets
* Mirfield Vets
* Penistone Vets
* Sandal Vets
* Wakefield Vets
* Waterloo Vets
* * * *
© 2024 Calder Vets Ltd, Part of Linnaeus, an Affiliate of Mars, Incorporated
Website by Clickingmad
* Legal Notice
* Privacy Statement
* Terms of Service
* Cookies
* Sitemap
* Modern Slavery Act
* Complaints
* Custom Charter
* Gender Pay Gap Report
* Accessibility
Cookie Settings
| biology | 2885454 | https://sv.wikipedia.org/wiki/Platysenta%20hypocritica | Platysenta hypocritica | Platysenta hypocritica är en fjärilsart som beskrevs av Dyar 1907. Platysenta hypocritica ingår i släktet Platysenta och familjen nattflyn. Inga underarter finns listade i Catalogue of Life.
Källor
Nattflyn
hypocritica | swedish | 1.29661 |
dog_eyes_glow/Tapetum_lucidum.txt | The tapetum lucidum (Latin for 'bright tapestry, coverlet'; /təˈpiːtəm ˈluːsɪdəm/ tə-PEE-təm LOO-sih-dəm; pl.: tapeta lucida) is a layer of tissue in the eye of many vertebrates and some other animals. Lying immediately behind the retina, it is a retroreflector. It reflects visible light back through the retina, increasing the light available to the photoreceptors (although slightly blurring the image). The tapetum lucidum contributes to the superior night vision of some animals. Many of these animals are nocturnal, especially carnivores, while others are deep sea animals.
Similar adaptations occur in some species of spiders. Haplorhine primates, including humans, are diurnal and lack a tapetum lucidum.
Function and mechanism[edit]
Choroid dissected from a calf's eye, tapetum lucidum appearing iridescent blue
The presence of a tapetum lucidum enables animals to see in dimmer light than would otherwise be possible. The tapetum lucidum, which is iridescent, reflects light roughly on the interference principles of thin-film optics, as seen in other iridescent tissues. However, the tapetum lucidum cells are leucophores, not iridophores.
The tapetum functions as a retroreflector which reflects light directly back along the light path. This serves to match the original and reflected light, thus maintaining the sharpness and contrast of the image on the retina. The tapetum lucidum reflects with constructive interference, thus increasing the quantity of light passing through the retina. In the cat, the tapetum lucidum increases the sensitivity of vision by 44%, allowing the cat to see light that is imperceptible to human eyes.
It has been speculated that some flashlight fish may use eyeshine both to detect and to communicate with other flashlight fish. American scientist Nathan H. Lents has proposed that the tapetum lucidum evolved in vertebrates, but not in cephalopods, which have a very similar eye, because of the backwards-facing nature of vertebrate photoreceptors. The tapetum boosts photosensitivity under conditions of low illumination, thus compensating for the suboptimal design of the vertebrate retina.
Classification[edit]
A classification of anatomical variants of tapeta lucida defines four types:
Retinal tapetum, as seen in teleosts (with a variety of reflecting materials from lipids to phenols), crocodiles (with guanine), marsupials (with lipid spheres), and fruit bats (with phospholipids). The tapetum lucidum is within the retinal pigment epithelium; in the other three types the tapetum is within the choroid behind the retina. Two anatomical classes can be distinguished: occlusible and non-occlusible.
The brownsnout spookfish has an extraordinary focusing mirror derived from a retinal tapetum.
Choroidal guainine tapetum, as seen in cartilaginous fish The tapetum is a palisade of cells containing stacks of flat hexagonal crystals of guanine.
Choroidal tapetum cellulosum, as seen in carnivores, rodents and cetacea. The tapetum consists of layers of cells containing organized, highly refractive crystals. These crystals are diverse in shape and makeup: dogs and ferrets use zinc, cats use riboflavin and zinc, and lemurs use only riboflavin.
Choroidal tapetum fibrosum, as seen in cows, sheep, goats and horses. The tapetum is an array of extracellular fibers, most commonly collagen.
The functional differences between these four structural classes of tapeta lucida are not known.
This section is missing information about bird anatomy: are they all retinal? If so, they should be moved up to the 4-type list.. Please expand the section to include this information. Further details may exist on the talk page. (August 2023)
This classification does not include tapeta lucida in birds. Kiwis, stone-curlews, the boat-billed heron, the flightless kākāpō and many nightjars, owls, and other night birds such as the swallow-tailed gull also possess a tapetum lucidum. Nightjars use a retinal tapetum lucidum composed of lipids.
Like humans, some animals lack a tapetum lucidum and they usually are diurnal. These include haplorhine primates, squirrels, some birds, red kangaroo, and pigs. Strepsirrhine primates are mostly nocturnal and, with the exception of several diurnal Eulemur species, have a tapetum lucidum of riboflavin crystals.
When a tapetum lucidum is present, its location on the eyeball varies with the placement of the eyeball in the head, such that in all cases the tapetum lucidum enhances night vision in the center of the animal's field of view.
Apart from its eyeshine, the tapetum lucidum itself has a color. It is often described as iridescent. In tigers it is greenish. In ruminants it may be golden green with a blue periphery, or whitish or pale blue with a lavender periphery. In dogs it may be whitish with a blue periphery. The color in reindeer changes seasonally, allowing the animals to better avoid predators in low-light winter at the price of blurrier vision.
Eyeshine[edit]
Reflection of camera flash from the tapetum lucidum
Eyeshine is a visible effect of the tapetum lucidum. When light shines into the eye of an animal having a tapetum lucidum, the pupil appears to glow. Eyeshine can be seen in many animals, in nature and in flash photographs. In low light, a hand-held flashlight is sufficient to produce eyeshine that is highly visible to humans (despite their inferior night vision). Eyeshine occurs in a wide variety of colors including white, blue, green, yellow, pink and red. However, since eyeshine is a type of iridescence, the color varies with the angle at which it is seen and the minerals which make up the reflective tapetum lucidum crystals.
White eyeshine occurs in many fish, especially walleye; blue eyeshine occurs in many mammals such as horses; green eyeshine occurs in mammals such as cats, dogs, and raccoons; and red eyeshine occurs in coyote, rodents, opossums and birds.
A three-month-old black Labrador puppy with apparent eyeshine
Although human eyes lack a tapetum lucidum, they still exhibit a weak reflection from the choroid, as can be seen in photography with the red-eye effect and with near-infrared eyeshine. Another effect in humans and other animals that may resemble eyeshine is leukocoria, which is a white shine indicative of abnormalities such as cataracts and cancers.
In blue-eyed cats and dogs[edit]
This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: "Tapetum lucidum" – news · newspapers · books · scholar · JSTOR (November 2022) (Learn how and when to remove this template message)
Odd-eyed cat with eyeshine, plus red-eye effect in one eye
Red eyeshine from a siamese cat mix with blue eyes
Cats and dogs with a blue eye color may display both eyeshine and red-eye effect. Both species have a tapetum lucidum, so their pupils may display eyeshine. In flash color photographs, however, individuals with blue eyes may also display a distinctive red eyeshine. Individuals with heterochromia may display red eyeshine in the blue eye and normal yellow/green/blue/white eyeshine in the other eye. These include odd-eyed cats and bi-eyed dogs. The red-eye effect is independent of the eyeshine: in some photographs of individuals with a tapetum lucidum and heterochromia, the eyeshine is dim, yet the pupil of the blue eye still appears red. This is most apparent when the individual is not looking into the camera because the tapetum lucidum is far less extensive than the retina.
In spiders[edit]
Most species of spider also have a tapetum, which is located only in their smaller, lateral eyes; the larger central eyes have no such structure. This consists of reflective crystalline deposits, and is thought to have a similar function to the structure of the same name in vertebrates. Four general patterns can be distinguished in spiders:
Primitive type (e.g. Mesothelae, Orthognatha) – a simple sheet behind the retina
Canoe-shape type (e.g. Araneidae, Theridiidae) – two lateral walls separated by a gap for the nerve fibres
Grated type (e.g. Lycosidae, Pisauridae) – a relatively complex, grill-shaped structure
No tapetum (e.g. Salticidae)
Uses by humans[edit]
In darkness, eyeshine reveals this raccoon
Humans use scanning for reflected eyeshine to detect and identify the species of animals in the dark, and deploying trained search dogs and search horses at night, as these animals benefit from improved night vision through this effect.
Using eyeshine to identify animals in the dark employs not only its color but also several other features. The color corresponds approximately to the type of tapetum lucidum, with some variation between species. Other features include the distance between pupils relative to their size; the height above ground; the manner of blinking (if any); and the movement of the eyeshine (bobbing, weaving, hopping, leaping, climbing, flying).
Artificial tapetum lucidum[edit]
Manufactured retroreflectors modeled after a tapetum lucidum are described in numerous patents and today have many uses. The earliest patent, first used in "Catseye" brand raised pavement markers, was inspired by the tapetum lucidum of a cat's eye.
Pathology[edit]
In dogs, certain drugs are known to disturb the precise organization of the crystals of the tapetum lucidum, thus compromising the dog's ability to see in low light. These drugs include ethambutol, macrolide antibiotics, dithizone, antimalarial medications, some receptor H2-antagonists, and cardiovascular agents. The disturbance "is attributed to the chelating action which removes zinc from the tapetal cells."
Gallery[edit]
Traditionally it has been difficult to take retinal images of animals with a tapetum lucidum because ophthalmoscopy devices designed for humans rely on a high level of on-axis illumination. This kind of illumination causes a great deal of reflex, or back-scatter, when it interacts with the tapetum. New devices with variable illumination can make this possible, however.
Heterochromatic dog with red-eye effect in blue eye
Aye-aye
Sportive lemur
Reflective eyes of a cat visible from a camera flash
A domestic tabby cat's green tapetum lucidum, apparent with camera flash
European nightjar
Subway passengers photographed with camera flash on small camera
See also[edit]
Defense mechanism (biology)
Emission theory (vision)
Nocturnal bottleneck
Walleye
Notes[edit]
^ The one exception to this generalization is the neotropical night monkey genus Aotus; they are sometimes described as having a tapetum lucidum of collagen fibrils, but lack the reflective riboflavin crystals present in the eyes of nocturnal strepsirrhine primates. | biology | 2630098 | https://sv.wikipedia.org/wiki/Leurophyllum%20tenebrosum | Leurophyllum tenebrosum | Leurophyllum tenebrosum är en insektsart som först beskrevs av Brunner von Wattenwyl 1895. Leurophyllum tenebrosum ingår i släktet Leurophyllum och familjen vårtbitare. Inga underarter finns listade i Catalogue of Life.
Källor
Vårtbitare
tenebrosum | swedish | 1.078907 |
animals_evolve_size/large-mammals-extinction.txt |
Gdoc / Admin The largest mammals have always been at the greatest risk of extinction – this is still the case today Humans hunted many of the world’s large mammals to extinction. This threat still exists today, but it doesn’t have to be that way. By: Hannah Ritchie May 09, 2022 Cite this article Reuse our work freely Look at the size of mammals over human history, and we see a clear trend: they’ve gotten smaller. We now have lots of evidence for this decline in mammal size worldwide. See the changes in the Levantine – the Eastern Mediterranean – where researchers have reconstructed the mass of mammals in the region going back more than one million years. To do this, they look at the fossils preserved in sediment layers; these sediment layers can be dated and let us leaf through the pages of the past. It lets us see what animals were around one million years ago, 500 thousand years ago, or ten thousand years ago. Note that the researchers did not include small mammals (those weighing less than 400 grams) in this dataset – these would have been very abundant across the record. The results are shown in the chart. We see a steep decline in the average mass of hunted mammals over time. Over the last 1.5 million years, the mean mass of hunted mammals decreased by more than 98%. 1.5 million years ago, our Homo erectus ancestors roamed the earth with mammals weighing several tonnes. There were the ‘straight-tusked elephants’ (which weighed 11 to 15 tonnes), the Southern Mammoth, and incredibly large hippos. Species-by-species, these majestic animals began to disappear. The driver of these large 'megafauna' extinctions is still contested. Changes in climate are proposed as one cause. But there's also evidence pointing towards another key culprit: humans. The small (our ancestors weighed around 60 kilograms), but big-brained, hominids hunted them to extinction. It is staggering how few of our ancestors were around at the time. Globally, there would have been a few million at most. The record suggests that humans have always hunted the largest mammals. This makes sense: it gives a good return on investment. One successful kill could feed a family for a long time. Bigger mammals are also easier to spot and track down. As we see from the study in the Levantine, until around 20,000 years ago, most hunted mammals were bigger than humans. But since then, the majority have been smaller. This overhunting of large mammals might have been the catalyst for our ancestors to engineer fine and intricate tools. Once we had run out of big animals to eat, we had to engineer tools to catch the smaller ones. 12,000 years ago, the average mass of mammals was around 30 kilograms. Around half a human. This is around the time that farming began. The disappearance of the largest mammals has happened across the world’s continents The wipeout of the largest mammals is a global phenomenon that we see across many regions. Indeed we find it so consistently that one way to estimate the dates at which humans first arrived on different continents is to track the timings of mammal extinctions. This period during which humans arrived in different world regions and large mammals went extinct across the world’s continents is called the ‘Quaternary Megafauna Extinction’. More than one hundred of the world’s largest mammals were driven to extinction. We see this clearly in the chart on the left-hand panel. It plots the number of mammals of a given size, from the smallest on the left to the heaviest on the right. In green are the mammals that survived this extinction event. In black are those that did not. Most of the large mammals went extinct. This is especially true across North and South America and Australia. Africa’s large mammals were spared slightly because mammals had cohabited with humans on the continent for hundreds of thousands of years already. Many of the largest mammals had either gone extinct already or had learned how to protect themselves and co-exist with our ancestors. What was true in the past is still true today. Many large mammals are still at risk of overhunting across Africa today. We see this on the right-hand panel of the chart. It shows the current distribution of mammal sizes across the continents and how threatened these mammals are. Note that the modern-day distribution of mammals is not exactly the same as 12 to 15,000 years ago – patterns of biodiversity have evolved since then. But what is consistent is that there is a strong bias toward extinction for the largest mammals, especially from hunting. In green are the animals not threatened with extinction. These tend to be smaller. In pink, yellow, and blue are animals at risk of extinction from hunting, habitat loss, or other threats, respectively. Just as in the past, the mammals at risk are the big ones. This extinction risk for the largest mammals is exacerbated by the fact that they have much slower reproduction times. The gestational periods for large animals are longer, which means that it takes a long time for populations to rebuild and recover. Small mammals, even if they’re being hunted, might be able to maintain healthy populations because they can reproduce so quickly. The biggest mammals are still at the greatest risk of extinction today but it doesn’t have to be this way The planet’s mammals might be much smaller than they were in the past but the size bias still exists. We might not be overhunting the twelve-tonne mammoths, but it’s still the 5000 kilogram elephants and rhinos that are most at risk of extinction. It doesn’t have to be this way. Some regions have reversed this trend in recent decades. There has been a resurgence of large mammals in Europe over the last fifty years. Populations of elk and brown bears have doubled or even quadrupled in size. The European Bison has been brought back from the brink. And the same is true for many other large mammals in the region. Legislated protections from hunting, exploitation and habitat loss saved them. The reintroduction of some has stopped them from becoming a long-lost memory. We see optimistic signs of animal protection elsewhere in the world. The Indian Rhino is making a comeback ; in the 1960s there were just 40 rhinos left. Now there are over 4,000. The same is true of the Javan Rhino , and the African elephant . If we fail to implement effective policies and regulations on hunting; poaching; wildlife trade; and habitat loss, we will simply continue the pattern of the past. But we don’t have to. It’s possible to break this cycle. In doing so we are the generation that will turn the tide on a development that stretches back through millions of years. Acknowledgements I would like to thank Max Roser, Daniel Gavrilov, Marcel Gerber, Daniel Bachler, Lars Yencken, Ike Saunders, Fiona Spooner and Bastian Herre for valuable suggestions and feedback on this article. Keep reading at Our World in Data Wild mammals have declined by 85% since the rise of humans, but there is a possible future where they flourish To protect the world’s wildlife we must improve crop yields — especially across Africa Endnotes Dembitzer, J., Barkai, R., Ben-Dor, M., & Meiri, S. (2022). Levantine overkill: 1.5 million years of hunting down the body size distribution . Quaternary Science Reviews, 276, 107316. The authors of the study note that the mean mass 10,500 years ago was just 1.7% of the mass 1.5 million years ago. If we take the decline from around 700,000 years ago, the reduction is even more dramatic: a decline of more than 99%. There are strong arguments and counter-arguments for the climate-human hypothesis on both sides. There is also another hypothesis climate changes and human impact drove these extinctions. Changes in climate might have caused a 'crash' in large mammal populations. Prior to human influence, these mammals might have been able to rebound and restore their populations. But human pressure halted this recovery, leading to their extinction. Andermann, T., Faurby, S., Turvey, S. T., Antonelli, A., & Silvestro, D. (2020). The past and future human impact on mammalian diversity. Science Advances, 6(36), eabb2313. Smith, F. A., Smith, R. E. E., Lyons, S. K., & Payne, J. L. (2018). Body size downgrading of mammals over the late Quaternary. Science, 360(6386), 310-313. Klein, R. G., Martin, P. S. (1984). Quaternary Extinctions: A Prehistoric Revolution. United Kingdom: University of Arizona Press. Barnosky, A. D. (2008). Megafauna biomass tradeoff as a driver of Quaternary and future extinctions. Proceedings of the National Academy of Sciences, 105(Supplement 1), 11543-11548. Sandom, C., Faurby, S., Sandel, B., & Svenning, J. C. (2014). Global late Quaternary megafauna extinctions linked to humans, not climate change. Proceedings of the Royal Society B: Biological Sciences, 281(1787), 20133254. The average weight of early hominid species – such as Neanderthals – was around 55 kilograms for females and 65 kilograms for males. Will, M., Pablos, A., & Stock, J. T. (2017). Long-term patterns of body mass and stature evolution within the hominin lineage . Royal Society Open Science, 4(11), 171339. The archeological evidence does not allow us to say directly which animals were killed off from human hunting and which by ‘natural causes’. Instead, researchers can measure historical changes across a range of environmental factors such as climate, temperature, rainfall, availability of vegetation, and dynamics of other species using biogeochemical markers such as isotopes. By modelling these historic changes, they can assess whether any of these environmental changes coincide with changes in species populations. By process of elimination, they can then decipher the remaining contribution of human pressures. Barkai, R., Rosell, J., Blasco, R., & Gopher, A. (2017). Fire for a reason: Barbecue at middle Pleistocene Qesem cave, Israel . Current Anthropology, 58(S16), S314-S328. The topic of why humans started farming remains controversial. Climate is likely to have played a role: the onset of agriculture was around the end of the last ice age. Before then, the climate would have been unsuitable for growing crops in many parts of the world. Still, this doesn’t explain why humans didn’t start farming during periods when the climate was stable and suitable. One hypothesis is that humans started growing their own food because they were running out of ‘wild’ supplies. Most of the animals that were left to hunt were small. Catching enough to keep everyone going would have been time-intensive and barely sustainable. This is especially true for growing populations. Maybe humans started farming because they had no choice. Larson, G., Piperno, D. R., Allaby, R. G., Purugganan, M. D., Andersson, L., Arroyo-Kalin, M., ... & Fuller, D. Q. (2014). Current perspectives and the future of domestication studies . Proceedings of the National Academy of Sciences , 111(17), 6139-6146. Belfer-Cohen, A., & Goring-Morris, A. N. (2011). Becoming farmers: the inside story . Current Anthropology, 52(S4), S209-S220. Archaeological evidence from Papua New Guinea, for example, shows that the agricultural transition was not marked by any significant changes in climate: the climate had been stable and suitable for farming for long periods of time. Roberts, P., Gaffney, D., Lee-Thorp, J., & Summerhayes, G. (2017). Persistent tropical foraging in the highlands of terminal Pleistocene/Holocene New Guinea . Nature Ecology & Evolution, 1(3), 1-6. Munro, N. D., Bar-Oz, G., Meier, J. S., Sapir-Hen, L., Stiner, M. C., & Yeshurun, R. (2018). The emergence of animal management in the Southern Levant . Scientific Reports, 8(1), 1-11. Lyons, S. K., Smith, F. A., & Brown, J. H. (2004). Of mice, mastodons and men: human-mediated extinctions on four continents. Evolutionary Ecology Research, 6(3), 339-358. Cardillo, M., Mace, G. M., Jones, K. E., Bielby, J., Bininda-Emonds, O. R., Sechrest, W., ... & Purvis, A. (2005). Multiple causes of high extinction risk in large mammal species . Science, 309(5738), 1239-1241. Deinet, S., Ieronymidou, C., McRae, L., Burfield, I.J., Foppen, R.P., Collen, B. and Böhm, M. (2013) Wildlife comeback in Europe: The recovery of selected mammal and bird species . Final report to Rewilding Europe by ZSL, BirdLife International and the European Bird Census Council. London, UK: ZSL. Cite this work Our articles and data visualizations rely on work from many different people and organizations. When citing this article, please also cite the underlying data sources. This article can be cited as: Hannah Ritchie (2022) - “The largest mammals have always been at the greatest risk of extinction – this is still the case today” Published online at OurWorldInData.org. Retrieved from: 'https://ourworldindata.org/large-mammals-extinction' [Online Resource] BibTeX citation @article{owid-large-mammals-extinction, author = {Hannah Ritchie}, title = {The largest mammals have always been at the greatest risk of extinction – this is still the case today}, journal = {Our World in Data}, year = {2022}, note = {https://ourworldindata.org/large-mammals-extinction} } Reuse this work freely All visualizations, data, and code produced by Our World in Data are completely open access under the Creative Commons BY license . You have the permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited. The data produced by third parties and made available by Our World in Data is subject to the license terms from the original third-party authors. We will always indicate the original source of the data in our documentation, so you should always check the license of any such third-party data before use and redistribution. All of our charts can be embedded in any site.
The largest mammals have always been at the greatest risk of extinction – this is still the case today
Look at the size of mammals over human history, and we see a clear trend: they’ve gotten smaller. We now have lots of evidence for this decline in mammal size worldwide. See the changes in the Levantine – the Eastern Mediterranean – where researchers have reconstructed the mass of mammals in the region going back more than one million years. To do this, they look at the fossils preserved in sediment layers; these sediment layers can be dated and let us leaf through the pages of the past. It lets us see what animals were around one million years ago, 500 thousand years ago, or ten thousand years ago. Note that the researchers did not include small mammals (those weighing less than 400 grams) in this dataset – these would have been very abundant across the record. The results are shown in the chart. We see a steep decline in the average mass of hunted mammals over time. Over the last 1.5 million years, the mean mass of hunted mammals decreased by more than 98%. 1.5 million years ago, our Homo erectus ancestors roamed the earth with mammals weighing several tonnes. There were the ‘straight-tusked elephants’ (which weighed 11 to 15 tonnes), the Southern Mammoth, and incredibly large hippos. Species-by-species, these majestic animals began to disappear. The driver of these large 'megafauna' extinctions is still contested. Changes in climate are proposed as one cause. But there's also evidence pointing towards another key culprit: humans. The small (our ancestors weighed around 60 kilograms), but big-brained, hominids hunted them to extinction. It is staggering how few of our ancestors were around at the time. Globally, there would have been a few million at most. The record suggests that humans have always hunted the largest mammals. This makes sense: it gives a good return on investment. One successful kill could feed a family for a long time. Bigger mammals are also easier to spot and track down. As we see from the study in the Levantine, until around 20,000 years ago, most hunted mammals were bigger than humans. But since then, the majority have been smaller. This overhunting of large mammals might have been the catalyst for our ancestors to engineer fine and intricate tools. Once we had run out of big animals to eat, we had to engineer tools to catch the smaller ones. 12,000 years ago, the average mass of mammals was around 30 kilograms. Around half a human. This is around the time that farming began.
Look at the size of mammals over human history, and we see a clear trend: they’ve gotten smaller. We now have lots of evidence for this decline in mammal size worldwide. See the changes in the Levantine – the Eastern Mediterranean – where researchers have reconstructed the mass of mammals in the region going back more than one million years. To do this, they look at the fossils preserved in sediment layers; these sediment layers can be dated and let us leaf through the pages of the past. It lets us see what animals were around one million years ago, 500 thousand years ago, or ten thousand years ago. Note that the researchers did not include small mammals (those weighing less than 400 grams) in this dataset – these would have been very abundant across the record. The results are shown in the chart. We see a steep decline in the average mass of hunted mammals over time. Over the last 1.5 million years, the mean mass of hunted mammals decreased by more than 98%. 1.5 million years ago, our Homo erectus ancestors roamed the earth with mammals weighing several tonnes. There were the ‘straight-tusked elephants’ (which weighed 11 to 15 tonnes), the Southern Mammoth, and incredibly large hippos. Species-by-species, these majestic animals began to disappear. The driver of these large 'megafauna' extinctions is still contested. Changes in climate are proposed as one cause. But there's also evidence pointing towards another key culprit: humans. The small (our ancestors weighed around 60 kilograms), but big-brained, hominids hunted them to extinction. It is staggering how few of our ancestors were around at the time. Globally, there would have been a few million at most. The record suggests that humans have always hunted the largest mammals. This makes sense: it gives a good return on investment. One successful kill could feed a family for a long time. Bigger mammals are also easier to spot and track down. As we see from the study in the Levantine, until around 20,000 years ago, most hunted mammals were bigger than humans. But since then, the majority have been smaller. This overhunting of large mammals might have been the catalyst for our ancestors to engineer fine and intricate tools. Once we had run out of big animals to eat, we had to engineer tools to catch the smaller ones. 12,000 years ago, the average mass of mammals was around 30 kilograms. Around half a human. This is around the time that farming began.
See the changes in the Levantine – the Eastern Mediterranean – where researchers have reconstructed the mass of mammals in the region going back more than one million years. To do this, they look at the fossils preserved in sediment layers; these sediment layers can be dated and let us leaf through the pages of the past. It lets us see what animals were around one million years ago, 500 thousand years ago, or ten thousand years ago. Note that the researchers did not include small mammals (those weighing less than 400 grams) in this dataset – these would have been very abundant across the record.
We see a steep decline in the average mass of hunted mammals over time. Over the last 1.5 million years, the mean mass of hunted mammals decreased by more than 98%.
1.5 million years ago, our Homo erectus ancestors roamed the earth with mammals weighing several tonnes. There were the ‘straight-tusked elephants’ (which weighed 11 to 15 tonnes), the Southern Mammoth, and incredibly large hippos. Species-by-species, these majestic animals began to disappear.
The driver of these large 'megafauna' extinctions is still contested. Changes in climate are proposed as one cause. But there's also evidence pointing towards another key culprit: humans.
The small (our ancestors weighed around 60 kilograms), but big-brained, hominids hunted them to extinction.
It is staggering how few of our ancestors were around at the time. Globally, there would have been a few million at most.
The record suggests that humans have always hunted the largest mammals. This makes sense: it gives a good return on investment. One successful kill could feed a family for a long time. Bigger mammals are also easier to spot and track down.
As we see from the study in the Levantine, until around 20,000 years ago, most hunted mammals were bigger than humans. But since then, the majority have been smaller.
This overhunting of large mammals might have been the catalyst for our ancestors to engineer fine and intricate tools. Once we had run out of big animals to eat, we had to engineer tools to catch the smaller ones.
12,000 years ago, the average mass of mammals was around 30 kilograms. Around half a human. This is around the time that farming began.
The disappearance of the largest mammals has happened across the world’s continents The wipeout of the largest mammals is a global phenomenon that we see across many regions. Indeed we find it so consistently that one way to estimate the dates at which humans first arrived on different continents is to track the timings of mammal extinctions. This period during which humans arrived in different world regions and large mammals went extinct across the world’s continents is called the ‘Quaternary Megafauna Extinction’. More than one hundred of the world’s largest mammals were driven to extinction. We see this clearly in the chart on the left-hand panel. It plots the number of mammals of a given size, from the smallest on the left to the heaviest on the right. In green are the mammals that survived this extinction event. In black are those that did not. Most of the large mammals went extinct. This is especially true across North and South America and Australia. Africa’s large mammals were spared slightly because mammals had cohabited with humans on the continent for hundreds of thousands of years already. Many of the largest mammals had either gone extinct already or had learned how to protect themselves and co-exist with our ancestors. What was true in the past is still true today. Many large mammals are still at risk of overhunting across Africa today. We see this on the right-hand panel of the chart. It shows the current distribution of mammal sizes across the continents and how threatened these mammals are. Note that the modern-day distribution of mammals is not exactly the same as 12 to 15,000 years ago – patterns of biodiversity have evolved since then. But what is consistent is that there is a strong bias toward extinction for the largest mammals, especially from hunting. In green are the animals not threatened with extinction. These tend to be smaller. In pink, yellow, and blue are animals at risk of extinction from hunting, habitat loss, or other threats, respectively. Just as in the past, the mammals at risk are the big ones. This extinction risk for the largest mammals is exacerbated by the fact that they have much slower reproduction times. The gestational periods for large animals are longer, which means that it takes a long time for populations to rebuild and recover. Small mammals, even if they’re being hunted, might be able to maintain healthy populations because they can reproduce so quickly.
The disappearance of the largest mammals has happened across the world’s continents The wipeout of the largest mammals is a global phenomenon that we see across many regions. Indeed we find it so consistently that one way to estimate the dates at which humans first arrived on different continents is to track the timings of mammal extinctions. This period during which humans arrived in different world regions and large mammals went extinct across the world’s continents is called the ‘Quaternary Megafauna Extinction’. More than one hundred of the world’s largest mammals were driven to extinction. We see this clearly in the chart on the left-hand panel. It plots the number of mammals of a given size, from the smallest on the left to the heaviest on the right. In green are the mammals that survived this extinction event. In black are those that did not. Most of the large mammals went extinct. This is especially true across North and South America and Australia. Africa’s large mammals were spared slightly because mammals had cohabited with humans on the continent for hundreds of thousands of years already. Many of the largest mammals had either gone extinct already or had learned how to protect themselves and co-exist with our ancestors. What was true in the past is still true today. Many large mammals are still at risk of overhunting across Africa today. We see this on the right-hand panel of the chart. It shows the current distribution of mammal sizes across the continents and how threatened these mammals are. Note that the modern-day distribution of mammals is not exactly the same as 12 to 15,000 years ago – patterns of biodiversity have evolved since then. But what is consistent is that there is a strong bias toward extinction for the largest mammals, especially from hunting. In green are the animals not threatened with extinction. These tend to be smaller. In pink, yellow, and blue are animals at risk of extinction from hunting, habitat loss, or other threats, respectively. Just as in the past, the mammals at risk are the big ones. This extinction risk for the largest mammals is exacerbated by the fact that they have much slower reproduction times. The gestational periods for large animals are longer, which means that it takes a long time for populations to rebuild and recover. Small mammals, even if they’re being hunted, might be able to maintain healthy populations because they can reproduce so quickly.
Indeed we find it so consistently that one way to estimate the dates at which humans first arrived on different continents is to track the timings of mammal extinctions.
This period during which humans arrived in different world regions and large mammals went extinct across the world’s continents is called the ‘Quaternary Megafauna Extinction’. More than one hundred of the world’s largest mammals were driven to extinction.
We see this clearly in the chart on the left-hand panel. It plots the number of mammals of a given size, from the smallest on the left to the heaviest on the right. In green are the mammals that survived this extinction event. In black are those that did not.
Most of the large mammals went extinct. This is especially true across North and South America and Australia. Africa’s large mammals were spared slightly because mammals had cohabited with humans on the continent for hundreds of thousands of years already. Many of the largest mammals had either gone extinct already or had learned how to protect themselves and co-exist with our ancestors.
Many large mammals are still at risk of overhunting across Africa today. We see this on the right-hand panel of the chart. It shows the current distribution of mammal sizes across the continents and how threatened these mammals are. Note that the modern-day distribution of mammals is not exactly the same as 12 to 15,000 years ago – patterns of biodiversity have evolved since then. But what is consistent is that there is a strong bias toward extinction for the largest mammals, especially from hunting.
In pink, yellow, and blue are animals at risk of extinction from hunting, habitat loss, or other threats, respectively. Just as in the past, the mammals at risk are the big ones.
This extinction risk for the largest mammals is exacerbated by the fact that they have much slower reproduction times. The gestational periods for large animals are longer, which means that it takes a long time for populations to rebuild and recover. Small mammals, even if they’re being hunted, might be able to maintain healthy populations because they can reproduce so quickly.
The planet’s mammals might be much smaller than they were in the past but the size bias still exists. We might not be overhunting the twelve-tonne mammoths, but it’s still the 5000 kilogram elephants and rhinos that are most at risk of extinction.
It doesn’t have to be this way. Some regions have reversed this trend in recent decades. There has been a resurgence of large mammals in Europe over the last fifty years. Populations of elk and brown bears have doubled or even quadrupled in size. The European Bison has been brought back from the brink. And the same is true for many other large mammals in the region.
Legislated protections from hunting, exploitation and habitat loss saved them. The reintroduction of some has stopped them from becoming a long-lost memory.
We see optimistic signs of animal protection elsewhere in the world. The Indian Rhino is making a comeback ; in the 1960s there were just 40 rhinos left. Now there are over 4,000. The same is true of the Javan Rhino , and the African elephant .
If we fail to implement effective policies and regulations on hunting; poaching; wildlife trade; and habitat loss, we will simply continue the pattern of the past. But we don’t have to. It’s possible to break this cycle. In doing so we are the generation that will turn the tide on a development that stretches back through millions of years.
Acknowledgements I would like to thank Max Roser, Daniel Gavrilov, Marcel Gerber, Daniel Bachler, Lars Yencken, Ike Saunders, Fiona Spooner and Bastian Herre for valuable suggestions and feedback on this article.
I would like to thank Max Roser, Daniel Gavrilov, Marcel Gerber, Daniel Bachler, Lars Yencken, Ike Saunders, Fiona Spooner and Bastian Herre for valuable suggestions and feedback on this article.
Wild mammals have declined by 85% since the rise of humans, but there is a possible future where they flourish
Endnotes Dembitzer, J., Barkai, R., Ben-Dor, M., & Meiri, S. (2022). Levantine overkill: 1.5 million years of hunting down the body size distribution . Quaternary Science Reviews, 276, 107316. The authors of the study note that the mean mass 10,500 years ago was just 1.7% of the mass 1.5 million years ago. If we take the decline from around 700,000 years ago, the reduction is even more dramatic: a decline of more than 99%. There are strong arguments and counter-arguments for the climate-human hypothesis on both sides. There is also another hypothesis climate changes and human impact drove these extinctions. Changes in climate might have caused a 'crash' in large mammal populations. Prior to human influence, these mammals might have been able to rebound and restore their populations. But human pressure halted this recovery, leading to their extinction. Andermann, T., Faurby, S., Turvey, S. T., Antonelli, A., & Silvestro, D. (2020). The past and future human impact on mammalian diversity. Science Advances, 6(36), eabb2313. Smith, F. A., Smith, R. E. E., Lyons, S. K., & Payne, J. L. (2018). Body size downgrading of mammals over the late Quaternary. Science, 360(6386), 310-313. Klein, R. G., Martin, P. S. (1984). Quaternary Extinctions: A Prehistoric Revolution. United Kingdom: University of Arizona Press. Barnosky, A. D. (2008). Megafauna biomass tradeoff as a driver of Quaternary and future extinctions. Proceedings of the National Academy of Sciences, 105(Supplement 1), 11543-11548. Sandom, C., Faurby, S., Sandel, B., & Svenning, J. C. (2014). Global late Quaternary megafauna extinctions linked to humans, not climate change. Proceedings of the Royal Society B: Biological Sciences, 281(1787), 20133254. The average weight of early hominid species – such as Neanderthals – was around 55 kilograms for females and 65 kilograms for males. Will, M., Pablos, A., & Stock, J. T. (2017). Long-term patterns of body mass and stature evolution within the hominin lineage . Royal Society Open Science, 4(11), 171339. The archeological evidence does not allow us to say directly which animals were killed off from human hunting and which by ‘natural causes’. Instead, researchers can measure historical changes across a range of environmental factors such as climate, temperature, rainfall, availability of vegetation, and dynamics of other species using biogeochemical markers such as isotopes. By modelling these historic changes, they can assess whether any of these environmental changes coincide with changes in species populations. By process of elimination, they can then decipher the remaining contribution of human pressures. Barkai, R., Rosell, J., Blasco, R., & Gopher, A. (2017). Fire for a reason: Barbecue at middle Pleistocene Qesem cave, Israel . Current Anthropology, 58(S16), S314-S328. The topic of why humans started farming remains controversial. Climate is likely to have played a role: the onset of agriculture was around the end of the last ice age. Before then, the climate would have been unsuitable for growing crops in many parts of the world. Still, this doesn’t explain why humans didn’t start farming during periods when the climate was stable and suitable. One hypothesis is that humans started growing their own food because they were running out of ‘wild’ supplies. Most of the animals that were left to hunt were small. Catching enough to keep everyone going would have been time-intensive and barely sustainable. This is especially true for growing populations. Maybe humans started farming because they had no choice. Larson, G., Piperno, D. R., Allaby, R. G., Purugganan, M. D., Andersson, L., Arroyo-Kalin, M., ... & Fuller, D. Q. (2014). Current perspectives and the future of domestication studies . Proceedings of the National Academy of Sciences , 111(17), 6139-6146. Belfer-Cohen, A., & Goring-Morris, A. N. (2011). Becoming farmers: the inside story . Current Anthropology, 52(S4), S209-S220. Archaeological evidence from Papua New Guinea, for example, shows that the agricultural transition was not marked by any significant changes in climate: the climate had been stable and suitable for farming for long periods of time. Roberts, P., Gaffney, D., Lee-Thorp, J., & Summerhayes, G. (2017). Persistent tropical foraging in the highlands of terminal Pleistocene/Holocene New Guinea . Nature Ecology & Evolution, 1(3), 1-6. Munro, N. D., Bar-Oz, G., Meier, J. S., Sapir-Hen, L., Stiner, M. C., & Yeshurun, R. (2018). The emergence of animal management in the Southern Levant . Scientific Reports, 8(1), 1-11. Lyons, S. K., Smith, F. A., & Brown, J. H. (2004). Of mice, mastodons and men: human-mediated extinctions on four continents. Evolutionary Ecology Research, 6(3), 339-358. Cardillo, M., Mace, G. M., Jones, K. E., Bielby, J., Bininda-Emonds, O. R., Sechrest, W., ... & Purvis, A. (2005). Multiple causes of high extinction risk in large mammal species . Science, 309(5738), 1239-1241. Deinet, S., Ieronymidou, C., McRae, L., Burfield, I.J., Foppen, R.P., Collen, B. and Böhm, M. (2013) Wildlife comeback in Europe: The recovery of selected mammal and bird species . Final report to Rewilding Europe by ZSL, BirdLife International and the European Bird Census Council. London, UK: ZSL.
Dembitzer, J., Barkai, R., Ben-Dor, M., & Meiri, S. (2022). Levantine overkill: 1.5 million years of hunting down the body size distribution . Quaternary Science Reviews, 276, 107316.
The authors of the study note that the mean mass 10,500 years ago was just 1.7% of the mass 1.5 million years ago. If we take the decline from around 700,000 years ago, the reduction is even more dramatic: a decline of more than 99%.
There are strong arguments and counter-arguments for the climate-human hypothesis on both sides. There is also another hypothesis climate changes and human impact drove these extinctions. Changes in climate might have caused a 'crash' in large mammal populations. Prior to human influence, these mammals might have been able to rebound and restore their populations. But human pressure halted this recovery, leading to their extinction.
Andermann, T., Faurby, S., Turvey, S. T., Antonelli, A., & Silvestro, D. (2020). The past and future human impact on mammalian diversity. Science Advances, 6(36), eabb2313.
Smith, F. A., Smith, R. E. E., Lyons, S. K., & Payne, J. L. (2018). Body size downgrading of mammals over the late Quaternary. Science, 360(6386), 310-313.
Klein, R. G., Martin, P. S. (1984). Quaternary Extinctions: A Prehistoric Revolution. United Kingdom: University of Arizona Press.
Barnosky, A. D. (2008). Megafauna biomass tradeoff as a driver of Quaternary and future extinctions. Proceedings of the National Academy of Sciences, 105(Supplement 1), 11543-11548.
Sandom, C., Faurby, S., Sandel, B., & Svenning, J. C. (2014). Global late Quaternary megafauna extinctions linked to humans, not climate change. Proceedings of the Royal Society B: Biological Sciences, 281(1787), 20133254.
The average weight of early hominid species – such as Neanderthals – was around 55 kilograms for females and 65 kilograms for males.
Will, M., Pablos, A., & Stock, J. T. (2017). Long-term patterns of body mass and stature evolution within the hominin lineage . Royal Society Open Science, 4(11), 171339.
The archeological evidence does not allow us to say directly which animals were killed off from human hunting and which by ‘natural causes’. Instead, researchers can measure historical changes across a range of environmental factors such as climate, temperature, rainfall, availability of vegetation, and dynamics of other species using biogeochemical markers such as isotopes. By modelling these historic changes, they can assess whether any of these environmental changes coincide with changes in species populations. By process of elimination, they can then decipher the remaining contribution of human pressures.
Barkai, R., Rosell, J., Blasco, R., & Gopher, A. (2017). Fire for a reason: Barbecue at middle Pleistocene Qesem cave, Israel . Current Anthropology, 58(S16), S314-S328.
The topic of why humans started farming remains controversial. Climate is likely to have played a role: the onset of agriculture was around the end of the last ice age. Before then, the climate would have been unsuitable for growing crops in many parts of the world. Still, this doesn’t explain why humans didn’t start farming during periods when the climate was stable and suitable.
One hypothesis is that humans started growing their own food because they were running out of ‘wild’ supplies. Most of the animals that were left to hunt were small. Catching enough to keep everyone going would have been time-intensive and barely sustainable. This is especially true for growing populations. Maybe humans started farming because they had no choice.
Larson, G., Piperno, D. R., Allaby, R. G., Purugganan, M. D., Andersson, L., Arroyo-Kalin, M., ... & Fuller, D. Q. (2014). Current perspectives and the future of domestication studies . Proceedings of the National Academy of Sciences , 111(17), 6139-6146.
Belfer-Cohen, A., & Goring-Morris, A. N. (2011). Becoming farmers: the inside story . Current Anthropology, 52(S4), S209-S220.
Archaeological evidence from Papua New Guinea, for example, shows that the agricultural transition was not marked by any significant changes in climate: the climate had been stable and suitable for farming for long periods of time.
Roberts, P., Gaffney, D., Lee-Thorp, J., & Summerhayes, G. (2017). Persistent tropical foraging in the highlands of terminal Pleistocene/Holocene New Guinea . Nature Ecology & Evolution, 1(3), 1-6.
Munro, N. D., Bar-Oz, G., Meier, J. S., Sapir-Hen, L., Stiner, M. C., & Yeshurun, R. (2018). The emergence of animal management in the Southern Levant . Scientific Reports, 8(1), 1-11.
Lyons, S. K., Smith, F. A., & Brown, J. H. (2004). Of mice, mastodons and men: human-mediated extinctions on four continents. Evolutionary Ecology Research, 6(3), 339-358.
Cardillo, M., Mace, G. M., Jones, K. E., Bielby, J., Bininda-Emonds, O. R., Sechrest, W., ... & Purvis, A. (2005). Multiple causes of high extinction risk in large mammal species . Science, 309(5738), 1239-1241.
Deinet, S., Ieronymidou, C., McRae, L., Burfield, I.J., Foppen, R.P., Collen, B. and Böhm, M. (2013) Wildlife comeback in Europe: The recovery of selected mammal and bird species . Final report to Rewilding Europe by ZSL, BirdLife International and the European Bird Census Council. London, UK: ZSL.
Cite this work Our articles and data visualizations rely on work from many different people and organizations. When citing this article, please also cite the underlying data sources. This article can be cited as: Hannah Ritchie (2022) - “The largest mammals have always been at the greatest risk of extinction – this is still the case today” Published online at OurWorldInData.org. Retrieved from: 'https://ourworldindata.org/large-mammals-extinction' [Online Resource] BibTeX citation @article{owid-large-mammals-extinction, author = {Hannah Ritchie}, title = {The largest mammals have always been at the greatest risk of extinction – this is still the case today}, journal = {Our World in Data}, year = {2022}, note = {https://ourworldindata.org/large-mammals-extinction} }
Our articles and data visualizations rely on work from many different people and organizations. When citing this article, please also cite the underlying data sources. This article can be cited as:
Hannah Ritchie (2022) - “The largest mammals have always been at the greatest risk of extinction – this is still the case today” Published online at OurWorldInData.org. Retrieved from: 'https://ourworldindata.org/large-mammals-extinction' [Online Resource]
Hannah Ritchie (2022) - “The largest mammals have always been at the greatest risk of extinction – this is still the case today” Published online at OurWorldInData.org. Retrieved from: 'https://ourworldindata.org/large-mammals-extinction' [Online Resource]
@article{owid-large-mammals-extinction, author = {Hannah Ritchie}, title = {The largest mammals have always been at the greatest risk of extinction – this is still the case today}, journal = {Our World in Data}, year = {2022}, note = {https://ourworldindata.org/large-mammals-extinction} }
@article{owid-large-mammals-extinction, author = {Hannah Ritchie}, title = {The largest mammals have always been at the greatest risk of extinction – this is still the case today}, journal = {Our World in Data}, year = {2022}, note = {https://ourworldindata.org/large-mammals-extinction} }
Reuse this work freely All visualizations, data, and code produced by Our World in Data are completely open access under the Creative Commons BY license . You have the permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited. The data produced by third parties and made available by Our World in Data is subject to the license terms from the original third-party authors. We will always indicate the original source of the data in our documentation, so you should always check the license of any such third-party data before use and redistribution. All of our charts can be embedded in any site.
All visualizations, data, and code produced by Our World in Data are completely open access under the Creative Commons BY license . You have the permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited.
The data produced by third parties and made available by Our World in Data is subject to the license terms from the original third-party authors. We will always indicate the original source of the data in our documentation, so you should always check the license of any such third-party data before use and redistribution.
Our World in Data is free and accessible for everyone. Help us do this work by making a donation. Donate now
Our World in Data is free and accessible for everyone. Help us do this work by making a donation. Donate now
About Contact Feedback Jobs Funding FAQs Donate Privacy policy Latest work All charts Twitter Facebook Instagram Threads GitHub Research & Writing RSS Feed Data Insights RSS Feed Licenses: All visualizations, data, and articles produced by Our World in Data are open access under the Creative Commons BY license . You have permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited. All the software and code that we write is open source and made available via GitHub under the permissive MIT license . All other material, including data produced by third parties and made available by Our World in Data, is subject to the license terms from the original third-party authors. Please consult our full legal disclaimer . Our World In Data is a project of the Global Change Data Lab , a registered charity in England and Wales (Charity Number 1186433).
About Contact Feedback Jobs Funding FAQs Donate Privacy policy Latest work All charts Twitter Facebook Instagram Threads GitHub Research & Writing RSS Feed Data Insights RSS Feed Licenses: All visualizations, data, and articles produced by Our World in Data are open access under the Creative Commons BY license . You have permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited. All the software and code that we write is open source and made available via GitHub under the permissive MIT license . All other material, including data produced by third parties and made available by Our World in Data, is subject to the license terms from the original third-party authors. Please consult our full legal disclaimer . Our World In Data is a project of the Global Change Data Lab , a registered charity in England and Wales (Charity Number 1186433).
Latest work All charts Twitter Facebook Instagram Threads GitHub Research & Writing RSS Feed Data Insights RSS Feed
Licenses: All visualizations, data, and articles produced by Our World in Data are open access under the Creative Commons BY license . You have permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited. All the software and code that we write is open source and made available via GitHub under the permissive MIT license . All other material, including data produced by third parties and made available by Our World in Data, is subject to the license terms from the original third-party authors. Please consult our full legal disclaimer . Our World In Data is a project of the Global Change Data Lab , a registered charity in England and Wales (Charity Number 1186433).
Licenses: All visualizations, data, and articles produced by Our World in Data are open access under the Creative Commons BY license . You have permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited. All the software and code that we write is open source and made available via GitHub under the permissive MIT license . All other material, including data produced by third parties and made available by Our World in Data, is subject to the license terms from the original third-party authors. Please consult our full legal disclaimer . Our World In Data is a project of the Global Change Data Lab , a registered charity in England and Wales (Charity Number 1186433).
Licenses: All visualizations, data, and articles produced by Our World in Data are open access under the Creative Commons BY license . You have permission to use, distribute, and reproduce these in any medium, provided the source and authors are credited. All the software and code that we write is open source and made available via GitHub under the permissive MIT license . All other material, including data produced by third parties and made available by Our World in Data, is subject to the license terms from the original third-party authors.
Our World In Data is a project of the Global Change Data Lab , a registered charity in England and Wales (Charity Number 1186433). | biology | 1024655 | https://sv.wikipedia.org/wiki/Leadbeaters%20falanger | Leadbeaters falanger | Leadbeaters falanger (Gymnobelideus leadbeateri) är ett pungdjur som tillhör familjen flygpungekorrar. Trots släktskapet saknar den flygförmåga. Djuret påminner mer om vanliga ekorrar.
Djurets namn syftar på John Leadbeater, en biolog som sysslade med taxonomi vid Museum of Victoria.
Utbredning
Arten förekommer i ett mindre 3 500 km² stort området i östra delen av den australiska delstaten Victoria.
Utseende
Pälsen är på ovansidan gråbrun och har en svart längsgående strimma, undersidan är ljusare till gulaktig. Ytterligare två strimmor finns i ansiktet från ögonen till öronen. Djuret når en kroppslängd mellan 15 och 17 centimeter samt en vikt mellan 120 och 165 gram. Därtill kommer en yvig svans på omkring 20 centimeters längd som inte är en gripsvans. Arten har korta klor vid varje tå och honans pung (marsupium) är väl utvecklad.
Ekologi
Leadbeaters falanger är aktiv på natten och lever i träd. Habitatet utgörs av kyliga fuktiga skogar upp till 1 500 meter över havet. Bon där de föder ungar byggs ofta i eukalyptusträd med håligheter och ligger vanligen 10 till 30 meter över marken.
Individerna lever i små grupper som vanligen består av en vuxen hona, en till tre hannar och deras ungar. Varje grupp har ett revir som är en till två hektar stort. Hos Leadbeaters falanger är honor det dominanta könet, alfahonan försvarar territoriet mot andra honor och parar sig bara med en av de könsmogna hannarna. Hannar är mindre aggressiva mot artfränder av samma kön.
Föda
Födan utgörs främst av insekter och trädens vätskor. De äter bland annat skalbaggar, spindlar och andra leddjur men gnager även på akacieträdens bark för att komma åt bastskiktet och kåda.
Fortplantning
Med undantag av de hetaste sommarmånaderna (januari, februari) kan honor para sig hela året. Dräktigheten är med 15 till 17 dagar ganska kortvarig (även för pungdjur). Per kull föds vanligen ett eller två ungdjur. Efter födelsen lever ungarna tre månader i pungen. Sedan stannar de 5 till 40 dagar i gruppens bo och deltar i utflykter. Efter 10 till 15 månader sluter honan att ge di och efter cirka två år är ungarna könsmogna. Livslängden i naturen kan vara 7,5 år och med människans vård upp till 9 år.
Leadbeaters falanger och människor
Arten upptäcktes för första gången under 1800-talet nära Melbourne. Efter 1909 registrerades en längre tid inga iakttagelser och därför antogs att djuret är utdött men 1961 upptäcktes arten igen.
På grund av arten krav på eukalyptusträd med håligheter är de känsliga för människans inverkning. Flera träd röjs eller förstörs under skogsbränder. Dessutom tar det 150 år innan ett nytt eukalyptusträd är tillräckligt stort.
Enligt uppskattningar finns bara 5000 individer kvar och det befaras att beståndet minskar ytterligare. IUCN listar arten som starkt hotad (endangered).
Referenser
Noter
Tryckta källor
Macdonald, David W. (red.), (1984) Jordens Djur 5: Pungdjuren, fladdermössen, insektätarna m.fl.. Stockholm: Bonnier Fakta. s. 130,
Ronald M. Nowak: Walker’s Mammals of the World. Johns Hopkins University Press, Baltimore/London 1999.
Externa länkar
Fåframtandade pungdjur
Däggdjur i australiska regionen | swedish | 0.807001 |
animals_evolve_size/Copes_rule.txt | Cope's rule, named after American paleontologist Edward Drinker Cope, postulates that population lineages tend to increase in body size over evolutionary time. It was never actually stated by Cope, although he favoured the occurrence of linear evolutionary trends. It is sometimes also known as the Cope–Depéret rule, because Charles Depéret explicitly advocated the idea. Theodor Eimer had also done so earlier. The term "Cope's rule" was apparently coined by Bernhard Rensch, based on the fact that Depéret had "lionized Cope" in his book. While the rule has been demonstrated in many instances, it does not hold true at all taxonomic levels, or in all clades. Larger body size is associated with increased fitness for a number of reasons, although there are also some disadvantages both on an individual and on a clade level: clades comprising larger individuals are more prone to extinction, which may act to limit the maximum size of organisms.
Function[edit]
Effects of growth[edit]
Directional selection appears to act on organisms' size, whereas it exhibits a far smaller effect on other morphological traits, though it is possible that this perception may be a result of sample bias. This selectional pressure can be explained by a number of advantages, both in terms of mating success and survival rate.
For example, larger organisms find it easier to avoid or fight off predators and capture prey, to reproduce, to kill competitors, to survive temporary lean times, and to resist rapid climatic changes. They may also potentially benefit from better thermal efficiency, increased intelligence, and a longer lifespan.
Offsetting these advantages, larger organisms require more food and water, and shift from r to K-selection. Their longer generation time means a longer period of reliance on the mother, and on a macroevolutionary scale restricts the clade's ability to evolve rapidly in response to changing environments.
Capping growth[edit]
Left unfettered, the trend of ever-larger size would produce organisms of gargantuan proportions. Therefore, some factors must limit this process.
At one level, it is possible that the clade's increased vulnerability to extinction, as its members become larger, means that no taxon survives long enough for individuals to reach huge sizes. There are probably also physically imposed limits to the size of some organisms; for instance, insects must be small enough for oxygen to diffuse to all parts of their bodies, flying birds must be light enough to fly, and the length of giraffes' necks may be limited by the blood pressure it is possible for their hearts to generate. Finally, there may be a competitive element, in that changes in size are necessarily accompanied by changes in ecological niche. For example, terrestrial carnivores over 21 kg almost always prey on organisms larger, not smaller, than themselves. If such a niche is already occupied, competitive pressure may oppose the directional selection. The three Canidae clades (Hesperocyoninae, Borophaginae, and Caninae) all show a trend towards larger size, although the first two are now extinct.
Validity[edit]
Cope recognised that clades of Cenozoic mammals appeared to originate as small individuals, and that body mass increased through a clade's history. Discussing the case of canid evolution in North America, Blaire Van Valkenburgh of UCLA and coworkers state:
Cope's rule, or the evolutionary trend toward larger body size, is common among mammals. Large size enhances the ability to avoid predators and capture prey, enhances reproductive success, and improves thermal efficiency. Moreover, in large carnivores, interspecific competition for food tends to be relatively intense, and bigger species tend to dominate and kill smaller competitors. Progenitors of hypercarnivorous lineages may have started as relatively small-bodied scavengers of large carcasses, similar to foxes and coyotes, with selection favoring both larger size and enhanced craniodental adaptations for meat eating. Moreover, the evolution of predator size is likely to be influenced by changes in prey size, and a significant trend toward larger size has been documented for large North American mammals, including both herbivores and carnivores, in the Cenozoic.
In some cases, the increase in body size may represent a passive, rather than an active, trend. In other words, the maximum size increases, but the minimum size does not; this is usually a result of size varying pseudo-randomly rather than directed evolution. This does not fall into Cope's rule sensu stricto, but is considered by many workers to be an example of "Cope's rule sensu lato". In other cases, an increase in size may in fact represent a transition to an optimal body size, and not imply that populations always develop to a larger size.
However, many palaeobiologists are skeptical of the validity of Cope's rule, which may merely represent a statistical artefact. Purported examples of Cope's rule often assume that the stratigraphic age of fossils is proportional to their "clade rank", a measure of how derived they are from an ancestral state; this relationship is in fact quite weak. Counterexamples to Cope's rule are common throughout geological time; although size increase does occur more often than not, it is by no means universal. For example, among genera of Cretaceous molluscs, an increase in size is no more common than stasis or a decrease. In many cases, Cope's rule only operates at certain taxonomic levels (for example, an order may obey Cope's rule, while its constituent families do not), or more generally, it may apply to only some clades of a taxon. Giant dinosaurs appear to have evolved dozens of times, in response to local environmental conditions.
Despite many counter-examples, Cope's rule is supported in many instances. For example, all marine invertebrate phyla except the molluscs show a size increase between the Cambrian and Permian. Collectively, dinosaurs exhibit an increase in body length over their evolution. Cope's rule also appears to hold in clades where a constraint on size is expected. For instance, one may expect the size of birds to be constrained, as larger masses mean more energy must be expended in flight. Birds have been suggested to follow Cope's law, although a subsequent reanalysis of the same data suggested otherwise.
An extensive study published in 2015 supports the presence of a trend toward larger body size in marine animals during the Phanerozoic. However, this trend was present mainly in the Paleozoic and Cenozoic; the Mesozoic was a period of relative stasis. The trend is not attributable simply to neutral drift in body size from small ancestors, and was mainly driven by a greater rate of diversification in classes of larger mean size. A smaller component of the overall trend is due to trends of increasing size within individual families.
Notes[edit]
^ In his paper, Rensch reproduced an erroneous citation of a work of Cope's (that he apparently had not read) from the English translation of Depéret's book. | biology | 4624432 | https://sv.wikipedia.org/wiki/Thespesia%20cubensis | Thespesia cubensis | Thespesia cubensis är en malvaväxtart som först beskrevs av Nathaniel Lord Britton och P. Wilson, och fick sitt nu gällande namn av J. B.Hutchinson. Thespesia cubensis ingår i släktet Thespesia och familjen malvaväxter. Inga underarter finns listade i Catalogue of Life.
Källor
Externa länkar
Malvaväxter
cubensis | swedish | 1.142493 |
animals_evolve_size/Cope's_rule.txt | Cope's rule, named after American paleontologist Edward Drinker Cope, postulates that population lineages tend to increase in body size over evolutionary time. It was never actually stated by Cope, although he favoured the occurrence of linear evolutionary trends. It is sometimes also known as the Cope–Depéret rule, because Charles Depéret explicitly advocated the idea. Theodor Eimer had also done so earlier. The term "Cope's rule" was apparently coined by Bernhard Rensch, based on the fact that Depéret had "lionized Cope" in his book. While the rule has been demonstrated in many instances, it does not hold true at all taxonomic levels, or in all clades. Larger body size is associated with increased fitness for a number of reasons, although there are also some disadvantages both on an individual and on a clade level: clades comprising larger individuals are more prone to extinction, which may act to limit the maximum size of organisms.
Function[edit]
Effects of growth[edit]
Directional selection appears to act on organisms' size, whereas it exhibits a far smaller effect on other morphological traits, though it is possible that this perception may be a result of sample bias. This selectional pressure can be explained by a number of advantages, both in terms of mating success and survival rate.
For example, larger organisms find it easier to avoid or fight off predators and capture prey, to reproduce, to kill competitors, to survive temporary lean times, and to resist rapid climatic changes. They may also potentially benefit from better thermal efficiency, increased intelligence, and a longer lifespan.
Offsetting these advantages, larger organisms require more food and water, and shift from r to K-selection. Their longer generation time means a longer period of reliance on the mother, and on a macroevolutionary scale restricts the clade's ability to evolve rapidly in response to changing environments.
Capping growth[edit]
Left unfettered, the trend of ever-larger size would produce organisms of gargantuan proportions. Therefore, some factors must limit this process.
At one level, it is possible that the clade's increased vulnerability to extinction, as its members become larger, means that no taxon survives long enough for individuals to reach huge sizes. There are probably also physically imposed limits to the size of some organisms; for instance, insects must be small enough for oxygen to diffuse to all parts of their bodies, flying birds must be light enough to fly, and the length of giraffes' necks may be limited by the blood pressure it is possible for their hearts to generate. Finally, there may be a competitive element, in that changes in size are necessarily accompanied by changes in ecological niche. For example, terrestrial carnivores over 21 kg almost always prey on organisms larger, not smaller, than themselves. If such a niche is already occupied, competitive pressure may oppose the directional selection. The three Canidae clades (Hesperocyoninae, Borophaginae, and Caninae) all show a trend towards larger size, although the first two are now extinct.
Validity[edit]
Cope recognised that clades of Cenozoic mammals appeared to originate as small individuals, and that body mass increased through a clade's history. Discussing the case of canid evolution in North America, Blaire Van Valkenburgh of UCLA and coworkers state:
Cope's rule, or the evolutionary trend toward larger body size, is common among mammals. Large size enhances the ability to avoid predators and capture prey, enhances reproductive success, and improves thermal efficiency. Moreover, in large carnivores, interspecific competition for food tends to be relatively intense, and bigger species tend to dominate and kill smaller competitors. Progenitors of hypercarnivorous lineages may have started as relatively small-bodied scavengers of large carcasses, similar to foxes and coyotes, with selection favoring both larger size and enhanced craniodental adaptations for meat eating. Moreover, the evolution of predator size is likely to be influenced by changes in prey size, and a significant trend toward larger size has been documented for large North American mammals, including both herbivores and carnivores, in the Cenozoic.
In some cases, the increase in body size may represent a passive, rather than an active, trend. In other words, the maximum size increases, but the minimum size does not; this is usually a result of size varying pseudo-randomly rather than directed evolution. This does not fall into Cope's rule sensu stricto, but is considered by many workers to be an example of "Cope's rule sensu lato". In other cases, an increase in size may in fact represent a transition to an optimal body size, and not imply that populations always develop to a larger size.
However, many palaeobiologists are skeptical of the validity of Cope's rule, which may merely represent a statistical artefact. Purported examples of Cope's rule often assume that the stratigraphic age of fossils is proportional to their "clade rank", a measure of how derived they are from an ancestral state; this relationship is in fact quite weak. Counterexamples to Cope's rule are common throughout geological time; although size increase does occur more often than not, it is by no means universal. For example, among genera of Cretaceous molluscs, an increase in size is no more common than stasis or a decrease. In many cases, Cope's rule only operates at certain taxonomic levels (for example, an order may obey Cope's rule, while its constituent families do not), or more generally, it may apply to only some clades of a taxon. Giant dinosaurs appear to have evolved dozens of times, in response to local environmental conditions.
Despite many counter-examples, Cope's rule is supported in many instances. For example, all marine invertebrate phyla except the molluscs show a size increase between the Cambrian and Permian. Collectively, dinosaurs exhibit an increase in body length over their evolution. Cope's rule also appears to hold in clades where a constraint on size is expected. For instance, one may expect the size of birds to be constrained, as larger masses mean more energy must be expended in flight. Birds have been suggested to follow Cope's law, although a subsequent reanalysis of the same data suggested otherwise.
An extensive study published in 2015 supports the presence of a trend toward larger body size in marine animals during the Phanerozoic. However, this trend was present mainly in the Paleozoic and Cenozoic; the Mesozoic was a period of relative stasis. The trend is not attributable simply to neutral drift in body size from small ancestors, and was mainly driven by a greater rate of diversification in classes of larger mean size. A smaller component of the overall trend is due to trends of increasing size within individual families.
Notes[edit]
^ In his paper, Rensch reproduced an erroneous citation of a work of Cope's (that he apparently had not read) from the English translation of Depéret's book. | biology | 4624432 | https://sv.wikipedia.org/wiki/Thespesia%20cubensis | Thespesia cubensis | Thespesia cubensis är en malvaväxtart som först beskrevs av Nathaniel Lord Britton och P. Wilson, och fick sitt nu gällande namn av J. B.Hutchinson. Thespesia cubensis ingår i släktet Thespesia och familjen malvaväxter. Inga underarter finns listade i Catalogue of Life.
Källor
Externa länkar
Malvaväxter
cubensis | swedish | 1.142493 |
animals_evolve_size/extinction-over-time.txt |
Smithsonian Institution Main Menu Visit Exhibits Research Education Events About Join us Donate Search Search Close Smithsonian National Museum of Natural History Extinction Over Time Breadcrumb Home Education Teaching Resources Paleontology Resources Extinction Over Time For years, paleontologists did not know what to make of this fossil from the ancient shark Helicoprion that lived 290 million years ago. It was proposed to be a weapon at the tip of the nose, an unusual dorsal fin, or a defensive tail adornment. Research revealed that it is actually a spiral of teeth (tooth whorl) that was used like a buzzsaw to grab and chop food. Smithsonian photo 2007-15308-helicoprion-shark by Chip Clark. Extinction of Plants and Animals Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution. Extinct Species List The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as: 1690 Dodo bird – extinct from predation by introduced pigs and cats 1768 Stellar’s sea cow – extinct from hunting for fur and oil 1870 Labrador duck – extinct from human competition for mussels and other shellfish 1900 Rocky mountain locust – extinct from habitat conversion to farmland 1936 Thylacine (Tasmanian tiger or wolf) – extinct from hunting, habitat loss, and competition with dogs 1952 Deepwater cisco fish – extinct from competition and predation by introduced fishes 1962 Hawaii chaff flower – extinct from habitat conversion to military installations 1989 Golden toad – extinct from climate change or other impacts 2004 St. Helena olive tree – extinct from logging and plantations Extinction Rates Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates. Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur. Five Mass Extinctions At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico. 2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean. 3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia. 4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet. 5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels. Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time. Are We Part of a Sixth Mass Extinction? At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species. Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times. Preventing Extinction The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction. The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest. Reversing Extinction Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth? Related Videos Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink Related Subject Guides Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery Related Activities Paleo Art - Edge of Extinction: Make Your Own Dinosaur Ecosystem Mural Evolve or Perish Board Game Resource Type Science Literacy Articles Grade Level 6-8 Topics Life Science, Paleontology Smithsonian National Museum of Natural History Smithsonian Email powered by BlackBaud ( Privacy Policy , Terms of Use ) Facebook Twitter Instagram Donate 1000 Madison Drive NW Washington, D.C. 20560 Free admission. Open every day except Dec. 25 from 10 AM to 5:30 PM Home Smithsonian Institution Terms of Use Privacy Policy Host an Event Jobs Press Blog Contact Us
Main Menu Visit Exhibits Research Education Events About Join us Donate Search Search Close Smithsonian National Museum of Natural History Extinction Over Time Breadcrumb Home Education Teaching Resources Paleontology Resources Extinction Over Time For years, paleontologists did not know what to make of this fossil from the ancient shark Helicoprion that lived 290 million years ago. It was proposed to be a weapon at the tip of the nose, an unusual dorsal fin, or a defensive tail adornment. Research revealed that it is actually a spiral of teeth (tooth whorl) that was used like a buzzsaw to grab and chop food. Smithsonian photo 2007-15308-helicoprion-shark by Chip Clark. Extinction of Plants and Animals Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution. Extinct Species List The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as: 1690 Dodo bird – extinct from predation by introduced pigs and cats 1768 Stellar’s sea cow – extinct from hunting for fur and oil 1870 Labrador duck – extinct from human competition for mussels and other shellfish 1900 Rocky mountain locust – extinct from habitat conversion to farmland 1936 Thylacine (Tasmanian tiger or wolf) – extinct from hunting, habitat loss, and competition with dogs 1952 Deepwater cisco fish – extinct from competition and predation by introduced fishes 1962 Hawaii chaff flower – extinct from habitat conversion to military installations 1989 Golden toad – extinct from climate change or other impacts 2004 St. Helena olive tree – extinct from logging and plantations Extinction Rates Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates. Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur. Five Mass Extinctions At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico. 2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean. 3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia. 4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet. 5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels. Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time. Are We Part of a Sixth Mass Extinction? At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species. Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times. Preventing Extinction The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction. The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest. Reversing Extinction Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth? Related Videos Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink Related Subject Guides Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery Related Activities Paleo Art - Edge of Extinction: Make Your Own Dinosaur Ecosystem Mural Evolve or Perish Board Game Resource Type Science Literacy Articles Grade Level 6-8 Topics Life Science, Paleontology Smithsonian National Museum of Natural History Smithsonian Email powered by BlackBaud ( Privacy Policy , Terms of Use ) Facebook Twitter Instagram Donate 1000 Madison Drive NW Washington, D.C. 20560 Free admission. Open every day except Dec. 25 from 10 AM to 5:30 PM Home Smithsonian Institution Terms of Use Privacy Policy Host an Event Jobs Press Blog Contact Us
Main Menu Visit Exhibits Research Education Events About Join us Donate Search Search Close Smithsonian National Museum of Natural History Extinction Over Time Breadcrumb Home Education Teaching Resources Paleontology Resources Extinction Over Time For years, paleontologists did not know what to make of this fossil from the ancient shark Helicoprion that lived 290 million years ago. It was proposed to be a weapon at the tip of the nose, an unusual dorsal fin, or a defensive tail adornment. Research revealed that it is actually a spiral of teeth (tooth whorl) that was used like a buzzsaw to grab and chop food. Smithsonian photo 2007-15308-helicoprion-shark by Chip Clark. Extinction of Plants and Animals Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution. Extinct Species List The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as: 1690 Dodo bird – extinct from predation by introduced pigs and cats 1768 Stellar’s sea cow – extinct from hunting for fur and oil 1870 Labrador duck – extinct from human competition for mussels and other shellfish 1900 Rocky mountain locust – extinct from habitat conversion to farmland 1936 Thylacine (Tasmanian tiger or wolf) – extinct from hunting, habitat loss, and competition with dogs 1952 Deepwater cisco fish – extinct from competition and predation by introduced fishes 1962 Hawaii chaff flower – extinct from habitat conversion to military installations 1989 Golden toad – extinct from climate change or other impacts 2004 St. Helena olive tree – extinct from logging and plantations Extinction Rates Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates. Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur. Five Mass Extinctions At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico. 2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean. 3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia. 4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet. 5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels. Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time. Are We Part of a Sixth Mass Extinction? At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species. Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times. Preventing Extinction The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction. The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest. Reversing Extinction Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth? Related Videos Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink Related Subject Guides Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery Related Activities Paleo Art - Edge of Extinction: Make Your Own Dinosaur Ecosystem Mural Evolve or Perish Board Game Resource Type Science Literacy Articles Grade Level 6-8 Topics Life Science, Paleontology Smithsonian National Museum of Natural History Smithsonian Email powered by BlackBaud ( Privacy Policy , Terms of Use ) Facebook Twitter Instagram Donate 1000 Madison Drive NW Washington, D.C. 20560 Free admission. Open every day except Dec. 25 from 10 AM to 5:30 PM Home Smithsonian Institution Terms of Use Privacy Policy Host an Event Jobs Press Blog Contact Us
Extinction Over Time Breadcrumb Home Education Teaching Resources Paleontology Resources Extinction Over Time For years, paleontologists did not know what to make of this fossil from the ancient shark Helicoprion that lived 290 million years ago. It was proposed to be a weapon at the tip of the nose, an unusual dorsal fin, or a defensive tail adornment. Research revealed that it is actually a spiral of teeth (tooth whorl) that was used like a buzzsaw to grab and chop food. Smithsonian photo 2007-15308-helicoprion-shark by Chip Clark. Extinction of Plants and Animals Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution. Extinct Species List The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as: 1690 Dodo bird – extinct from predation by introduced pigs and cats 1768 Stellar’s sea cow – extinct from hunting for fur and oil 1870 Labrador duck – extinct from human competition for mussels and other shellfish 1900 Rocky mountain locust – extinct from habitat conversion to farmland 1936 Thylacine (Tasmanian tiger or wolf) – extinct from hunting, habitat loss, and competition with dogs 1952 Deepwater cisco fish – extinct from competition and predation by introduced fishes 1962 Hawaii chaff flower – extinct from habitat conversion to military installations 1989 Golden toad – extinct from climate change or other impacts 2004 St. Helena olive tree – extinct from logging and plantations Extinction Rates Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates. Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur. Five Mass Extinctions At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico. 2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean. 3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia. 4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet. 5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels. Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time. Are We Part of a Sixth Mass Extinction? At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species. Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times. Preventing Extinction The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction. The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest. Reversing Extinction Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth? Related Videos Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink Related Subject Guides Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery Related Activities Paleo Art - Edge of Extinction: Make Your Own Dinosaur Ecosystem Mural Evolve or Perish Board Game Resource Type Science Literacy Articles Grade Level 6-8 Topics Life Science, Paleontology
Breadcrumb Home Education Teaching Resources Paleontology Resources Extinction Over Time For years, paleontologists did not know what to make of this fossil from the ancient shark Helicoprion that lived 290 million years ago. It was proposed to be a weapon at the tip of the nose, an unusual dorsal fin, or a defensive tail adornment. Research revealed that it is actually a spiral of teeth (tooth whorl) that was used like a buzzsaw to grab and chop food. Smithsonian photo 2007-15308-helicoprion-shark by Chip Clark. Extinction of Plants and Animals Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution. Extinct Species List The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as: 1690 Dodo bird – extinct from predation by introduced pigs and cats 1768 Stellar’s sea cow – extinct from hunting for fur and oil 1870 Labrador duck – extinct from human competition for mussels and other shellfish 1900 Rocky mountain locust – extinct from habitat conversion to farmland 1936 Thylacine (Tasmanian tiger or wolf) – extinct from hunting, habitat loss, and competition with dogs 1952 Deepwater cisco fish – extinct from competition and predation by introduced fishes 1962 Hawaii chaff flower – extinct from habitat conversion to military installations 1989 Golden toad – extinct from climate change or other impacts 2004 St. Helena olive tree – extinct from logging and plantations Extinction Rates Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates. Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur. Five Mass Extinctions At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico. 2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean. 3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia. 4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet. 5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels. Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time. Are We Part of a Sixth Mass Extinction? At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species. Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times. Preventing Extinction The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction. The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest. Reversing Extinction Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth? Related Videos Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink Related Subject Guides Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery Related Activities Paleo Art - Edge of Extinction: Make Your Own Dinosaur Ecosystem Mural Evolve or Perish Board Game Resource Type Science Literacy Articles Grade Level 6-8 Topics Life Science, Paleontology
Extinction of Plants and Animals Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution. Extinct Species List The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as: 1690 Dodo bird – extinct from predation by introduced pigs and cats 1768 Stellar’s sea cow – extinct from hunting for fur and oil 1870 Labrador duck – extinct from human competition for mussels and other shellfish 1900 Rocky mountain locust – extinct from habitat conversion to farmland 1936 Thylacine (Tasmanian tiger or wolf) – extinct from hunting, habitat loss, and competition with dogs 1952 Deepwater cisco fish – extinct from competition and predation by introduced fishes 1962 Hawaii chaff flower – extinct from habitat conversion to military installations 1989 Golden toad – extinct from climate change or other impacts 2004 St. Helena olive tree – extinct from logging and plantations Extinction Rates Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates. Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur. Five Mass Extinctions At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico. 2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean. 3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia. 4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet. 5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels. Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time. Are We Part of a Sixth Mass Extinction? At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species. Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times. Preventing Extinction The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction. The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest. Reversing Extinction Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth? Related Videos Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink Related Subject Guides Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery Related Activities Paleo Art - Edge of Extinction: Make Your Own Dinosaur Ecosystem Mural Evolve or Perish Board Game Resource Type Science Literacy Articles Grade Level 6-8 Topics Life Science, Paleontology
Extinction of Plants and Animals Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution. Extinct Species List The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as: 1690 Dodo bird – extinct from predation by introduced pigs and cats 1768 Stellar’s sea cow – extinct from hunting for fur and oil 1870 Labrador duck – extinct from human competition for mussels and other shellfish 1900 Rocky mountain locust – extinct from habitat conversion to farmland 1936 Thylacine (Tasmanian tiger or wolf) – extinct from hunting, habitat loss, and competition with dogs 1952 Deepwater cisco fish – extinct from competition and predation by introduced fishes 1962 Hawaii chaff flower – extinct from habitat conversion to military installations 1989 Golden toad – extinct from climate change or other impacts 2004 St. Helena olive tree – extinct from logging and plantations Extinction Rates Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates. Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur. Five Mass Extinctions At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico. 2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean. 3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia. 4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet. 5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels. Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time. Are We Part of a Sixth Mass Extinction? At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species. Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times. Preventing Extinction The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction. The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest. Reversing Extinction Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth? Related Videos Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink Related Subject Guides Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery Related Activities Paleo Art - Edge of Extinction: Make Your Own Dinosaur Ecosystem Mural Evolve or Perish Board Game
Extinction of Plants and Animals Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution. Extinct Species List The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as: 1690 Dodo bird – extinct from predation by introduced pigs and cats 1768 Stellar’s sea cow – extinct from hunting for fur and oil 1870 Labrador duck – extinct from human competition for mussels and other shellfish 1900 Rocky mountain locust – extinct from habitat conversion to farmland 1936 Thylacine (Tasmanian tiger or wolf) – extinct from hunting, habitat loss, and competition with dogs 1952 Deepwater cisco fish – extinct from competition and predation by introduced fishes 1962 Hawaii chaff flower – extinct from habitat conversion to military installations 1989 Golden toad – extinct from climate change or other impacts 2004 St. Helena olive tree – extinct from logging and plantations Extinction Rates Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates. Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur. Five Mass Extinctions At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized. 1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico. 2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean. 3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia. 4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet. 5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels. Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time. Are We Part of a Sixth Mass Extinction? At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species. Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times. Preventing Extinction The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction. The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest. Reversing Extinction Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth? Related Videos Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink Related Subject Guides Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery Related Activities Paleo Art - Edge of Extinction: Make Your Own Dinosaur Ecosystem Mural Evolve or Perish Board Game
Extinction is the death of all members of a species of plants, animals, or other organisms. One of the most dramatic examples of a modern extinction is the passenger pigeon. Until the early 1800s, billions of passenger pigeons darkened the skies of the United States in spectacular migratory flocks. Easy to trap or shoot, passenger pigeons became a popular, cheap food. Commercial hunters killed them in vast numbers, eventually decimating the population. The last passenger pigeon , named Martha, died in the Cincinnati Zoological Garden in 1914, and was donated to the Smithsonian Institution.
The passenger pigeon is one of many hundreds of extinctions that have been caused by human activities in the past few centuries, such as:
Recent studies estimate about eight million species on Earth, of which at least 15,000 are threatened with extinction. It’s hard to pinpoint the exact extinction rate because many endangered species have not been identified or studied yet. A number of scientists grapple with improving methods for estimating extinction rates.
Regardless, scientists agree that today’s extinction rate is hundreds, or even thousands, of times higher than the natural baseline rate. Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur.
At five other times in the past, rates of extinction have soared. These are called mass extinctions , when huge numbers of species disappear in a relatively short period of time. Paleontologists know about these extinctions from remains of organisms with durable skeletons that fossilized.
1. End of the Cretaceous (66 million years ago): Extinction of many species in both marine and terrestrial habitats including pterosaurs, mosasaurs and other marine reptiles, many insects, and all non-Avian dinosaurs. The scientific consensus is that this mass extinction was caused by environmental consequences from the impact of a large asteroid hitting Earth in the vicinity of what is now Mexico.
2. Late Triassic (199 million years ago): Extinction of many marine sponges, gastropods, bivalves, cephalopods, brachiopods, as well as some terrestrial insects and vertebrates. The extinction coincides with massive volcanic eruptions along the margins of what is now the Atlantic Ocean.
3. End Permian (252 million years ago): Earth’s largest extinction event, decimating most marine species such as all trilobites, plus insects and other terrestrial animals. Most scientific evidence suggests the causes were global warming and atmospheric changes associated with huge volcanic eruptions in what is now Siberia.
4. Late Devonian (378 million years ago): Extinction of many marine species, including corals, brachiopods, and single-celled foraminiferans, from causes that are not well understood yet.
5. Late Ordovician (447 million years ago): Extinction of marine organisms such as some bryozoans, reef-building brachiopods, trilobites, graptolites, and conodonts as a result of global cooling, glaciation, and lower sea levels.
Smithsonian Paleobiologists continue to study the role that past extinctions had on plants, animals, and other species. Dr. Gene Hunt studies how the relatedness and diversity of organisms relates to what happens to them in an extinction event. Dr. Richard Bambach conducts research on variation in marine biodiversity in relation to different extinction events. By studying the evolution and extinction of tiny organisms called foraminifera, Dr. Brian Huber assesses how Earth's conditions have changed over time.
At the end of the last ice age, 10,000 years ago, many North American animals went extinct, including mammoths , mastodons , and glyptodonts . While climate changes were a factor, paleontologists have evidence that overhunting by humans was also to blame. Early humans worked cooperatively to trap and slaughter large animals in pits. About the same time, humans began farming, settling down and making drastic changes in the habitats of other species.
Starting in the 1800s, industrialization drove up extinction rates and has continued to do so. For example, Chinese river dolphins , foothill yellow-legged frogs , and sockeye salmon are among the many species currently endangered by water pollution, dams, and other industrial pressures on rivers. Smithsonian Anthropologist Dr. Torben Rick leads an effort to understand how human activities affect biodiversity by studying interactions between humans and other species in the Channel Islands from ancient to modern times.
The science of conservation biology focuses on managing ecosystems to prevent species from going extinct. Because we can’t protect everything, conservation efforts target particular species or habitats. Smithsonian scientist Dr. Brian Gratwicke is the “amphibian avenger” for his work to save populations of frogs from extinction. The Smithsonian is part of an alliance of institutions (Global Tiger Initiative) working to save wild tigers from extinction.
The value of a species may be judged by various criteria, depending on who is making decisions about what to conserve. For example, cultural value is important in efforts to conserve populations of Pacific salmon . A Smithsonian exhibit in the Sant Ocean Hall shows how salmon for centuries have shaped a way of life for Native Americans living in the Pacific Northwest.
Recent improvements in genetic engineering have raised questions about bringing extinct species back to life. Since Dolly the sheep was cloned in 1996, scientists know it is possible to create an organism from the DNA in a single cell. Stored in museum collections throughout the world are specimens of extinct animals containing DNA. The idea of using DNA to revive extinct species and repopulating them is controversial. How would we choose which ones? How would they impact species still on Earth?
Mass Extinction - Solving the Dinosaur Mystery Bird Extinctions Human Impacts and Extinction of Freshwater Snails What Tiny Marine Fossils Reveal about Extinction Did Humans Cause Pleistocene Megafaunal Extinctions? Ferrets Back from the Brink
Mass Extinction of Large Dinosaurs and More Bird Extinctions in Recent Geologic Time Freshwater Snails and Ecosystems Triassic Life, Extinction, and Recovery
Smithsonian National Museum of Natural History Smithsonian Email powered by BlackBaud ( Privacy Policy , Terms of Use ) Facebook Twitter Instagram Donate 1000 Madison Drive NW Washington, D.C. 20560 Free admission. Open every day except Dec. 25 from 10 AM to 5:30 PM
Email powered by BlackBaud ( Privacy Policy , Terms of Use ) Facebook Twitter Instagram Donate 1000 Madison Drive NW Washington, D.C. 20560 Free admission. Open every day except Dec. 25 from 10 AM to 5:30 PM
1000 Madison Drive NW Washington, D.C. 20560 Free admission. Open every day except Dec. 25 from 10 AM to 5:30 PM | biology | 1464 | https://sv.wikipedia.org/wiki/Paleontologi | Paleontologi | Paleontologi är vetenskapen om förhistoriskt liv, samt organismers evolution och interaktioner med varandra och sin miljö (deras paleoekologi). Som en "historisk vetenskap" försöker den förklara orsaker istället för att göra experiment för att studera effekterna. Den som arbetar med paleontologi kallas för paleontolog. Paleontologi är en del av naturvetenskapen.
Paleontologiska observationer har blivit dokumenterade till 500-talet f.Kr.. Paleontologin blev etablerad genom Georges Cuviers arbete på 1700-talet inom komparativ anatomi för att sedan utvecklas snabbt under 1800-talet. Fossil i Kina på 1990-talet har gett ny information angående den tidigaste evolutionen av djur, tidiga fiskar, dinosaurier samt fåglars och däggdjurens evolution.
Paleontologi som vetenskap ligger på gränsen mellan geologi och biologi genom att man studerar biologin hos utdöda djur och växter och deras utveckling genom tiden. Den använder tekniker hämtade från en mängd vetenskaper, bland annat biokemi, matematik och ingenjörskonst. Då kunskapen har ökat inom området, har paleontologin utvecklat speciella subdivisioner, bland annat paleobiologi (läran om utdött liv), paleoantropologi (läran om människans evolution), paleobotanik (läran om utdöda växter), paleogeografi, paleoklimatologi och paleozoologi (läran om utdöda djur). Geokemiska bevis har använts till livets evolution innan organismer var stora nog att bilda fossil.
Både organismerna och deras spår finns bevarade som fossil, som är de vanligaste bevisen om förhistoriskt liv. Att beräkna åldern på fossil är viktigt men svårt. Ibland kan närliggande stenlager dateras med radiometrisk datering, som ger absoluta åldrar som är exakta till 0,5%, men oftast måste paleontologer gå på inexakta dateringar genom "pussel" av biostratigrafi. Att klassificera utdöda organismer är också svårt, då många inte passar in i klassificeringen för nutida levande djur, och paleontologer måste ofta använda kladistik för evolutionära grupper. De sista 25 åren av 1900-talet utvecklades molekylär fylogenetik, som undersöker hur nära organismer är relaterade till varandra genom att undersöka hur lika DNA:et är i deras genom. Molekylär fylogenetik har också använts till att beräkna när arter har separerats från varandra.
Källor
Se även
Dinosaurier
Fossil
Naturhistoria
Geologisk tidsskala
Förhistoriskt liv | swedish | 0.6233 |
animals_evolve_size/Small-animals-thrive-after-mass-extinctions-say-scientists.txt |
Skip to main content Skip to main menu Skip to search Skip to footer Why is Christian Science in our name? Why is Christian Science in our name? Our name is about honesty. The Monitor is owned by The Christian Science Church, and we’ve always been transparent about that. The Church publishes the Monitor because it sees good journalism as vital to progress in the world. Since 1908, we’ve aimed “to injure no man, but to bless all mankind,” as our founder, Mary Baker Eddy, put it. Here, you’ll find award-winning journalism not driven by commercial influences – a news organization that takes seriously its mission to uplift the world by seeking solutions and finding reasons for credible hope. Explore values journalism About us Log in Log out Values Topics Regions About us Log in Account Subscribe Give a gift Search Subscribe: $11/Month Log in About us Free newsletters One month free trial to the Monitor Daily Give a gift Log out Manage your account Subscription FAQs Contact Customer Service Current Issues Monitor Daily Monitor Weekly digital edition Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values About us Free newsletters Follow us: Explore Values Journalism Behind the news are values that drive people and nations. Explore them here. Compassion Cooperation Equality Hope Resilience Respect Responsibility Safety Transformation Trust More News & Values Recent Stories Peace Gaza cease-fire talks: Egypt, US hopeful a formula has been found Forgiveness A tender way to treat armed militias Balance Beyond TikTok ban: How one state is grappling with teens and scrolling See all News & Values stories Special project Can trust bring connection and hope in a divided world? Discover how through global news stories. Rebuilding trust News Economy Education Environment Foreign Policy Law & Courts Politics Science Security Society Culture Arts Food Movies Music Television The Home Forum In a Word Monitor Movie Guide All Culture Books Author Q&As Book Reviews Reader Recommendations All Books Commentary The Monitor's View Readers Respond A Christian Science Perspective From the Editors All Commentary More News Briefs Points of Progress People Making a Difference Photo Galleries Podcasts Monitor Breakfast Monitor Daily April 29, 2024 When persistence is the demand Our top stories today deal with very difficult conversations. One involves cease-fire prospects in Gaza; the other, women’s profound concerns after the overturning of Harvey Weinstein’s conviction for felony sex crimes, including rape.The root issues in both cases are not new ones. Nor are there easy answers. Yet negotiators keep pressing against suspicion and violence. Advocates point to shifts in attitudes that may seem incremental, but can be built upon. It’s a reminder of the essential ingredient in pursuing progress amid searing and seemingly intractable situations: persistence. Listen to or read today's issue Regions Africa Americas Asia Pacific Europe Middle East South & Central Asia USA All World Recent Stories Harvey Weinstein’s rape conviction was overturned. What does that mean for #MeToo? Gaza cease-fire talks: Egypt, US hopeful a formula has been found Americans don’t trust self-driving semis. We’re about to share the road with them. Featured Coverage The Christian Science Monitor's coverage of the 2023 war between Hamas and Israel, and related articles. Connect with the stories War in the Middle East Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values Free newsletters One month free trial to the Monitor Daily The Christian Science Monitor The Christian Science Monitor is an international news organization offering calm, thoughtful, award-winning coverage for independent thinkers. We tackle difficult conversations and divisive issues–we don’t shy away from hard problems. But you’ll find in each Monitor news story qualities that can lead to solutions and unite us–qualities such as respect, resilience, hope, and fairness. About us Search Log out Manage your account Subscription FAQs Contact Customer Service Current Issues Monitor Daily Monitor Weekly digital edition of stories this month > Get unlimited stories Your subscription makes our work possible. We want to bridge divides to reach everyone. Subscribe Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close × Science Small animals thrive after mass extinctions, say scientists A new study suggests that mass extinction of ancient larger animals led to the dominance of tiny species. | Courtesy Bob Nicholls An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction. Loading... By Beatrice Gitau Staff @Chepkangai November 14, 2015 From blue whales to elephants, most of the world’s most massive species are facing extinction. A new study of fish fossils suggests that when large vertebrates become extinct, evolution does not replace them for many years. Researchers, after analyzing fish that lived about 350 million years ago, have concluded that a mass extinction known as the Hangenberg event caused large species to die off while smaller species survived. "Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine, " said Lauren Sallan, an environmental scientist at the University of Pennsylvania, in a news release. Her findings suggest that the smaller fish had a unique advantage over their larger counterparts: they breed much, much faster than their giant cousins. "The end result is an ocean in which most sharks are less than a meter [three feet] and most fishes and tetrapods are less than 10 centimeters," or smaller than a grapefruit, said Dr. Sallen. "Yet these are the ancestors of everything that dominates from then on, including humans." Recommended 14 animals declared extinct in the 21st century Paleontologists have long debated the changes in the body sizes of animals over time. One theory, known as Cope's rule, says a species tends to enlarge over time to avoid predation and to become better hunters. Another theory says that all things being equal, animals become larger in the presence of increased oxygen, or in colder climates. Another idea, known as the Lilliput Effect, holds that after mass extinctions, there will inevitably be a temporary trend toward small body size. It’s named after a fictional island in the book “Gulliver’s Travels” that’s inhabited by tiny people. Many scientists believe that we are on the brink of – if not in the midst of – a sixth mass extinction . This summer, scientists released a report indicating that humans are chiefly to blame for the mass extinction that is already underway. Recommended 14 animals declared extinct in the 21st century But these same scientists say that aggressive conservation efforts may yet stave off a true mass extinction. Humpback whales, for example, were recently recommended for removal from the endangered species list . "This will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations – notably habitat loss, overexploitation for economic gain, and climate change," wrote the research team, including scientists from Stanford, Princeton, and Berkeley, in their report . Get stories that empower and uplift daily. By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . If the present extinction does eliminate the planet's largest animals, the new study suggests they will not be replaced any time soon. "It doesn't matter what is eliminating the large fish or what is making ecosystems unstable," Sallan said. "These disturbances are shifting natural selection so that smaller, faster-reproducing fish are more likely to keep going, and it could take a really long time to get those bigger fish back in any sizable way." You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe Real news can be honest, hopeful, credible, constructive. What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world. Mark Sappenfield , Editor [email protected] Subscribe Related stories Test your knowledge Name that animal! First Look From hypercarnivores to megafauna: How huge animals shaped their world Global News Blog Why park rangers risk their lives to protect gorillas – and how it's working Why did those giant rats go extinct? And could they come back? 'Extinct' Omura's whales spotted: How rare are they? 10,000-year-old lion cubs found frozen in Siberia offer link to distant past Share this article Copy link Link copied. × Mark Sappenfield Editor Dear Reader, About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”: “Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.” If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism. But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in. The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908. We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.” If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com. Subscribe to insightful journalism Read this article in https://www.csmonitor.com/Science/2015/1114/Small-animals-thrive-after-mass-extinctions-say-scientists Start your subscription today https://www.csmonitor.com/subscribe Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close × ISSN 2573-3850 (online) Follow us: About Contact Us Subscribe Give a Gift Subscription Support Monitor Journalism Free Newsletters Careers Social Media Community Connect Content Map Text Edition RSS Reprints & Permissions Multimedia A Christian Science Perspective © 1980–2024 The Christian Science Monitor. All Rights Reserved. Terms. Privacy Policy. Cookies Settings This website uses cookies to improve functionality and performance. By continuing to browse the site you are agreeing to our use of cookies . Close
Why is Christian Science in our name? Why is Christian Science in our name? Our name is about honesty. The Monitor is owned by The Christian Science Church, and we’ve always been transparent about that. The Church publishes the Monitor because it sees good journalism as vital to progress in the world. Since 1908, we’ve aimed “to injure no man, but to bless all mankind,” as our founder, Mary Baker Eddy, put it. Here, you’ll find award-winning journalism not driven by commercial influences – a news organization that takes seriously its mission to uplift the world by seeking solutions and finding reasons for credible hope. Explore values journalism About us Log in Log out Values Topics Regions About us Log in Account Subscribe Give a gift
Why is Christian Science in our name? Why is Christian Science in our name? Our name is about honesty. The Monitor is owned by The Christian Science Church, and we’ve always been transparent about that. The Church publishes the Monitor because it sees good journalism as vital to progress in the world. Since 1908, we’ve aimed “to injure no man, but to bless all mankind,” as our founder, Mary Baker Eddy, put it. Here, you’ll find award-winning journalism not driven by commercial influences – a news organization that takes seriously its mission to uplift the world by seeking solutions and finding reasons for credible hope. Explore values journalism About us
Why is Christian Science in our name? Our name is about honesty. The Monitor is owned by The Christian Science Church, and we’ve always been transparent about that. The Church publishes the Monitor because it sees good journalism as vital to progress in the world. Since 1908, we’ve aimed “to injure no man, but to bless all mankind,” as our founder, Mary Baker Eddy, put it. Here, you’ll find award-winning journalism not driven by commercial influences – a news organization that takes seriously its mission to uplift the world by seeking solutions and finding reasons for credible hope. Explore values journalism About us
Why is Christian Science in our name? Our name is about honesty. The Monitor is owned by The Christian Science Church, and we’ve always been transparent about that. The Church publishes the Monitor because it sees good journalism as vital to progress in the world. Since 1908, we’ve aimed “to injure no man, but to bless all mankind,” as our founder, Mary Baker Eddy, put it. Here, you’ll find award-winning journalism not driven by commercial influences – a news organization that takes seriously its mission to uplift the world by seeking solutions and finding reasons for credible hope. Explore values journalism About us
Why is Christian Science in our name? Our name is about honesty. The Monitor is owned by The Christian Science Church, and we’ve always been transparent about that. The Church publishes the Monitor because it sees good journalism as vital to progress in the world. Since 1908, we’ve aimed “to injure no man, but to bless all mankind,” as our founder, Mary Baker Eddy, put it. Here, you’ll find award-winning journalism not driven by commercial influences – a news organization that takes seriously its mission to uplift the world by seeking solutions and finding reasons for credible hope. Explore values journalism About us
Our name is about honesty. The Monitor is owned by The Christian Science Church, and we’ve always been transparent about that.
The Church publishes the Monitor because it sees good journalism as vital to progress in the world. Since 1908, we’ve aimed “to injure no man, but to bless all mankind,” as our founder, Mary Baker Eddy, put it.
Here, you’ll find award-winning journalism not driven by commercial influences – a news organization that takes seriously its mission to uplift the world by seeking solutions and finding reasons for credible hope.
Search Subscribe: $11/Month Log in About us Free newsletters One month free trial to the Monitor Daily Give a gift Log out Manage your account Subscription FAQs Contact Customer Service Current Issues Monitor Daily Monitor Weekly digital edition Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values About us Free newsletters Follow us:
Subscribe: $11/Month Log in About us Free newsletters One month free trial to the Monitor Daily Give a gift Log out Manage your account Subscription FAQs Contact Customer Service Current Issues Monitor Daily Monitor Weekly digital edition Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values About us Free newsletters
Give a gift Log out Manage your account Subscription FAQs Contact Customer Service
Give a gift Log out Manage your account Subscription FAQs Contact Customer Service
Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values
Explore Values Journalism Behind the news are values that drive people and nations. Explore them here. Compassion Cooperation Equality Hope Resilience Respect Responsibility Safety Transformation Trust More News & Values Recent Stories Peace Gaza cease-fire talks: Egypt, US hopeful a formula has been found Forgiveness A tender way to treat armed militias Balance Beyond TikTok ban: How one state is grappling with teens and scrolling See all News & Values stories Special project Can trust bring connection and hope in a divided world? Discover how through global news stories. Rebuilding trust
Explore Values Journalism Behind the news are values that drive people and nations. Explore them here. Compassion Cooperation Equality Hope Resilience Respect Responsibility Safety Transformation Trust More News & Values Recent Stories Peace Gaza cease-fire talks: Egypt, US hopeful a formula has been found Forgiveness A tender way to treat armed militias Balance Beyond TikTok ban: How one state is grappling with teens and scrolling See all News & Values stories Special project Can trust bring connection and hope in a divided world? Discover how through global news stories. Rebuilding trust
Explore Values Journalism Behind the news are values that drive people and nations. Explore them here. Compassion Cooperation Equality Hope Resilience Respect Responsibility Safety Transformation Trust More News & Values
Explore Values Journalism Behind the news are values that drive people and nations. Explore them here. Compassion Cooperation Equality Hope Resilience Respect Responsibility Safety Transformation Trust More News & Values
Recent Stories Peace Gaza cease-fire talks: Egypt, US hopeful a formula has been found Forgiveness A tender way to treat armed militias Balance Beyond TikTok ban: How one state is grappling with teens and scrolling See all News & Values stories
Peace Gaza cease-fire talks: Egypt, US hopeful a formula has been found Forgiveness A tender way to treat armed militias Balance Beyond TikTok ban: How one state is grappling with teens and scrolling
Special project Can trust bring connection and hope in a divided world? Discover how through global news stories. Rebuilding trust
Can trust bring connection and hope in a divided world? Discover how through global news stories. Rebuilding trust
Can trust bring connection and hope in a divided world? Discover how through global news stories. Rebuilding trust
News Economy Education Environment Foreign Policy Law & Courts Politics Science Security Society Culture Arts Food Movies Music Television The Home Forum In a Word Monitor Movie Guide All Culture Books Author Q&As Book Reviews Reader Recommendations All Books Commentary The Monitor's View Readers Respond A Christian Science Perspective From the Editors All Commentary More News Briefs Points of Progress People Making a Difference Photo Galleries Podcasts Monitor Breakfast Monitor Daily April 29, 2024 When persistence is the demand Our top stories today deal with very difficult conversations. One involves cease-fire prospects in Gaza; the other, women’s profound concerns after the overturning of Harvey Weinstein’s conviction for felony sex crimes, including rape.The root issues in both cases are not new ones. Nor are there easy answers. Yet negotiators keep pressing against suspicion and violence. Advocates point to shifts in attitudes that may seem incremental, but can be built upon. It’s a reminder of the essential ingredient in pursuing progress amid searing and seemingly intractable situations: persistence. Listen to or read today's issue
News Economy Education Environment Foreign Policy Law & Courts Politics Science Security Society Culture Arts Food Movies Music Television The Home Forum In a Word Monitor Movie Guide All Culture Books Author Q&As Book Reviews Reader Recommendations All Books Commentary The Monitor's View Readers Respond A Christian Science Perspective From the Editors All Commentary More News Briefs Points of Progress People Making a Difference Photo Galleries Podcasts Monitor Breakfast Monitor Daily April 29, 2024 When persistence is the demand Our top stories today deal with very difficult conversations. One involves cease-fire prospects in Gaza; the other, women’s profound concerns after the overturning of Harvey Weinstein’s conviction for felony sex crimes, including rape.The root issues in both cases are not new ones. Nor are there easy answers. Yet negotiators keep pressing against suspicion and violence. Advocates point to shifts in attitudes that may seem incremental, but can be built upon. It’s a reminder of the essential ingredient in pursuing progress amid searing and seemingly intractable situations: persistence. Listen to or read today's issue
News Economy Education Environment Foreign Policy Law & Courts Politics Science Security Society Culture Arts Food Movies Music Television The Home Forum In a Word Monitor Movie Guide All Culture Books Author Q&As Book Reviews Reader Recommendations All Books Commentary The Monitor's View Readers Respond A Christian Science Perspective From the Editors All Commentary More News Briefs Points of Progress People Making a Difference Photo Galleries Podcasts Monitor Breakfast
News Economy Education Environment Foreign Policy Law & Courts Politics Science Security Society Culture Arts Food Movies Music Television The Home Forum In a Word Monitor Movie Guide All Culture Books Author Q&As Book Reviews Reader Recommendations All Books Commentary The Monitor's View Readers Respond A Christian Science Perspective From the Editors All Commentary More News Briefs Points of Progress People Making a Difference Photo Galleries Podcasts Monitor Breakfast
Commentary The Monitor's View Readers Respond A Christian Science Perspective From the Editors All Commentary
Monitor Daily April 29, 2024 When persistence is the demand Our top stories today deal with very difficult conversations. One involves cease-fire prospects in Gaza; the other, women’s profound concerns after the overturning of Harvey Weinstein’s conviction for felony sex crimes, including rape.The root issues in both cases are not new ones. Nor are there easy answers. Yet negotiators keep pressing against suspicion and violence. Advocates point to shifts in attitudes that may seem incremental, but can be built upon. It’s a reminder of the essential ingredient in pursuing progress amid searing and seemingly intractable situations: persistence. Listen to or read today's issue
April 29, 2024 When persistence is the demand Our top stories today deal with very difficult conversations. One involves cease-fire prospects in Gaza; the other, women’s profound concerns after the overturning of Harvey Weinstein’s conviction for felony sex crimes, including rape.The root issues in both cases are not new ones. Nor are there easy answers. Yet negotiators keep pressing against suspicion and violence. Advocates point to shifts in attitudes that may seem incremental, but can be built upon. It’s a reminder of the essential ingredient in pursuing progress amid searing and seemingly intractable situations: persistence.
April 29, 2024 When persistence is the demand Our top stories today deal with very difficult conversations. One involves cease-fire prospects in Gaza; the other, women’s profound concerns after the overturning of Harvey Weinstein’s conviction for felony sex crimes, including rape.The root issues in both cases are not new ones. Nor are there easy answers. Yet negotiators keep pressing against suspicion and violence. Advocates point to shifts in attitudes that may seem incremental, but can be built upon. It’s a reminder of the essential ingredient in pursuing progress amid searing and seemingly intractable situations: persistence.
Our top stories today deal with very difficult conversations. One involves cease-fire prospects in Gaza; the other, women’s profound concerns after the overturning of Harvey Weinstein’s conviction for felony sex crimes, including rape.The root issues in both cases are not new ones. Nor are there easy answers. Yet negotiators keep pressing against suspicion and violence. Advocates point to shifts in attitudes that may seem incremental, but can be built upon. It’s a reminder of the essential ingredient in pursuing progress amid searing and seemingly intractable situations: persistence.
Our top stories today deal with very difficult conversations. One involves cease-fire prospects in Gaza; the other, women’s profound concerns after the overturning of Harvey Weinstein’s conviction for felony sex crimes, including rape.The root issues in both cases are not new ones. Nor are there easy answers. Yet negotiators keep pressing against suspicion and violence. Advocates point to shifts in attitudes that may seem incremental, but can be built upon. It’s a reminder of the essential ingredient in pursuing progress amid searing and seemingly intractable situations: persistence.
Regions Africa Americas Asia Pacific Europe Middle East South & Central Asia USA All World Recent Stories Harvey Weinstein’s rape conviction was overturned. What does that mean for #MeToo? Gaza cease-fire talks: Egypt, US hopeful a formula has been found Americans don’t trust self-driving semis. We’re about to share the road with them. Featured Coverage The Christian Science Monitor's coverage of the 2023 war between Hamas and Israel, and related articles. Connect with the stories War in the Middle East
Regions Africa Americas Asia Pacific Europe Middle East South & Central Asia USA All World Recent Stories Harvey Weinstein’s rape conviction was overturned. What does that mean for #MeToo? Gaza cease-fire talks: Egypt, US hopeful a formula has been found Americans don’t trust self-driving semis. We’re about to share the road with them. Featured Coverage The Christian Science Monitor's coverage of the 2023 war between Hamas and Israel, and related articles. Connect with the stories War in the Middle East
Recent Stories Harvey Weinstein’s rape conviction was overturned. What does that mean for #MeToo? Gaza cease-fire talks: Egypt, US hopeful a formula has been found Americans don’t trust self-driving semis. We’re about to share the road with them.
Harvey Weinstein’s rape conviction was overturned. What does that mean for #MeToo? Gaza cease-fire talks: Egypt, US hopeful a formula has been found Americans don’t trust self-driving semis. We’re about to share the road with them.
Featured Coverage The Christian Science Monitor's coverage of the 2023 war between Hamas and Israel, and related articles. Connect with the stories War in the Middle East
The Christian Science Monitor's coverage of the 2023 war between Hamas and Israel, and related articles. Connect with the stories War in the Middle East
The Christian Science Monitor's coverage of the 2023 war between Hamas and Israel, and related articles. Connect with the stories War in the Middle East
The Christian Science Monitor's coverage of the 2023 war between Hamas and Israel, and related articles. Connect with the stories
The Christian Science Monitor's coverage of the 2023 war between Hamas and Israel, and related articles.
Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values Free newsletters One month free trial to the Monitor Daily The Christian Science Monitor The Christian Science Monitor is an international news organization offering calm, thoughtful, award-winning coverage for independent thinkers. We tackle difficult conversations and divisive issues–we don’t shy away from hard problems. But you’ll find in each Monitor news story qualities that can lead to solutions and unite us–qualities such as respect, resilience, hope, and fairness. About us
Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values Free newsletters One month free trial to the Monitor Daily The Christian Science Monitor The Christian Science Monitor is an international news organization offering calm, thoughtful, award-winning coverage for independent thinkers. We tackle difficult conversations and divisive issues–we don’t shy away from hard problems. But you’ll find in each Monitor news story qualities that can lead to solutions and unite us–qualities such as respect, resilience, hope, and fairness. About us
Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values Free newsletters One month free trial to the Monitor Daily
Values Behind the News A deeper view that unites instead of divides, connecting why the story matters to you. Explore News & Values Free newsletters One month free trial to the Monitor Daily
The Christian Science Monitor The Christian Science Monitor is an international news organization offering calm, thoughtful, award-winning coverage for independent thinkers. We tackle difficult conversations and divisive issues–we don’t shy away from hard problems. But you’ll find in each Monitor news story qualities that can lead to solutions and unite us–qualities such as respect, resilience, hope, and fairness. About us
The Christian Science Monitor The Christian Science Monitor is an international news organization offering calm, thoughtful, award-winning coverage for independent thinkers. We tackle difficult conversations and divisive issues–we don’t shy away from hard problems. But you’ll find in each Monitor news story qualities that can lead to solutions and unite us–qualities such as respect, resilience, hope, and fairness. About us
The Christian Science Monitor is an international news organization offering calm, thoughtful, award-winning coverage for independent thinkers. We tackle difficult conversations and divisive issues–we don’t shy away from hard problems. But you’ll find in each Monitor news story qualities that can lead to solutions and unite us–qualities such as respect, resilience, hope, and fairness.
Log out Manage your account Subscription FAQs Contact Customer Service Current Issues Monitor Daily Monitor Weekly digital edition
Log out Manage your account Subscription FAQs Contact Customer Service Current Issues Monitor Daily Monitor Weekly digital edition
Log out Manage your account Subscription FAQs Contact Customer Service Current Issues Monitor Daily Monitor Weekly digital edition
of stories this month > Get unlimited stories Your subscription makes our work possible. We want to bridge divides to reach everyone. Subscribe
of stories this month > Get unlimited stories Your subscription makes our work possible. We want to bridge divides to reach everyone. Subscribe
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close ×
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close ×
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close ×
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy .
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy .
See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy .
Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close ×
The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday
Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional
Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday
Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday
Science Small animals thrive after mass extinctions, say scientists A new study suggests that mass extinction of ancient larger animals led to the dominance of tiny species. | Courtesy Bob Nicholls An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction. Loading... By Beatrice Gitau Staff @Chepkangai November 14, 2015 From blue whales to elephants, most of the world’s most massive species are facing extinction. A new study of fish fossils suggests that when large vertebrates become extinct, evolution does not replace them for many years. Researchers, after analyzing fish that lived about 350 million years ago, have concluded that a mass extinction known as the Hangenberg event caused large species to die off while smaller species survived. "Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine, " said Lauren Sallan, an environmental scientist at the University of Pennsylvania, in a news release. Her findings suggest that the smaller fish had a unique advantage over their larger counterparts: they breed much, much faster than their giant cousins. "The end result is an ocean in which most sharks are less than a meter [three feet] and most fishes and tetrapods are less than 10 centimeters," or smaller than a grapefruit, said Dr. Sallen. "Yet these are the ancestors of everything that dominates from then on, including humans." Recommended 14 animals declared extinct in the 21st century Paleontologists have long debated the changes in the body sizes of animals over time. One theory, known as Cope's rule, says a species tends to enlarge over time to avoid predation and to become better hunters. Another theory says that all things being equal, animals become larger in the presence of increased oxygen, or in colder climates. Another idea, known as the Lilliput Effect, holds that after mass extinctions, there will inevitably be a temporary trend toward small body size. It’s named after a fictional island in the book “Gulliver’s Travels” that’s inhabited by tiny people. Many scientists believe that we are on the brink of – if not in the midst of – a sixth mass extinction . This summer, scientists released a report indicating that humans are chiefly to blame for the mass extinction that is already underway. Recommended 14 animals declared extinct in the 21st century But these same scientists say that aggressive conservation efforts may yet stave off a true mass extinction. Humpback whales, for example, were recently recommended for removal from the endangered species list . "This will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations – notably habitat loss, overexploitation for economic gain, and climate change," wrote the research team, including scientists from Stanford, Princeton, and Berkeley, in their report . Get stories that empower and uplift daily. By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . If the present extinction does eliminate the planet's largest animals, the new study suggests they will not be replaced any time soon. "It doesn't matter what is eliminating the large fish or what is making ecosystems unstable," Sallan said. "These disturbances are shifting natural selection so that smaller, faster-reproducing fish are more likely to keep going, and it could take a really long time to get those bigger fish back in any sizable way." You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe Real news can be honest, hopeful, credible, constructive. What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world. Mark Sappenfield , Editor [email protected] Subscribe Related stories Test your knowledge Name that animal! First Look From hypercarnivores to megafauna: How huge animals shaped their world Global News Blog Why park rangers risk their lives to protect gorillas – and how it's working Why did those giant rats go extinct? And could they come back? 'Extinct' Omura's whales spotted: How rare are they? 10,000-year-old lion cubs found frozen in Siberia offer link to distant past Share this article Copy link Link copied. × Mark Sappenfield Editor Dear Reader, About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”: “Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.” If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism. But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in. The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908. We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.” If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com. Subscribe to insightful journalism
A new study suggests that mass extinction of ancient larger animals led to the dominance of tiny species.
A new study suggests that mass extinction of ancient larger animals led to the dominance of tiny species.
A new study suggests that mass extinction of ancient larger animals led to the dominance of tiny species.
A new study suggests that mass extinction of ancient larger animals led to the dominance of tiny species.
| Courtesy Bob Nicholls An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction. Loading...
| Courtesy Bob Nicholls An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction. Loading...
| Courtesy Bob Nicholls An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction.
| Courtesy Bob Nicholls An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction.
| Courtesy Bob Nicholls An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction.
An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction.
An illustration of small sharks and fishes of the Mississippian Period, more than 300 million years ago. Researchers found shrinkage in sizes of some groups of species following a mass extinction.
By Beatrice Gitau Staff @Chepkangai November 14, 2015 From blue whales to elephants, most of the world’s most massive species are facing extinction. A new study of fish fossils suggests that when large vertebrates become extinct, evolution does not replace them for many years. Researchers, after analyzing fish that lived about 350 million years ago, have concluded that a mass extinction known as the Hangenberg event caused large species to die off while smaller species survived. "Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine, " said Lauren Sallan, an environmental scientist at the University of Pennsylvania, in a news release. Her findings suggest that the smaller fish had a unique advantage over their larger counterparts: they breed much, much faster than their giant cousins. "The end result is an ocean in which most sharks are less than a meter [three feet] and most fishes and tetrapods are less than 10 centimeters," or smaller than a grapefruit, said Dr. Sallen. "Yet these are the ancestors of everything that dominates from then on, including humans." Recommended 14 animals declared extinct in the 21st century Paleontologists have long debated the changes in the body sizes of animals over time. One theory, known as Cope's rule, says a species tends to enlarge over time to avoid predation and to become better hunters. Another theory says that all things being equal, animals become larger in the presence of increased oxygen, or in colder climates. Another idea, known as the Lilliput Effect, holds that after mass extinctions, there will inevitably be a temporary trend toward small body size. It’s named after a fictional island in the book “Gulliver’s Travels” that’s inhabited by tiny people. Many scientists believe that we are on the brink of – if not in the midst of – a sixth mass extinction . This summer, scientists released a report indicating that humans are chiefly to blame for the mass extinction that is already underway. Recommended 14 animals declared extinct in the 21st century But these same scientists say that aggressive conservation efforts may yet stave off a true mass extinction. Humpback whales, for example, were recently recommended for removal from the endangered species list . "This will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations – notably habitat loss, overexploitation for economic gain, and climate change," wrote the research team, including scientists from Stanford, Princeton, and Berkeley, in their report . Get stories that empower and uplift daily. By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . If the present extinction does eliminate the planet's largest animals, the new study suggests they will not be replaced any time soon. "It doesn't matter what is eliminating the large fish or what is making ecosystems unstable," Sallan said. "These disturbances are shifting natural selection so that smaller, faster-reproducing fish are more likely to keep going, and it could take a really long time to get those bigger fish back in any sizable way." You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe Real news can be honest, hopeful, credible, constructive. What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world. Mark Sappenfield , Editor [email protected] Subscribe Related stories Test your knowledge Name that animal! First Look From hypercarnivores to megafauna: How huge animals shaped their world Global News Blog Why park rangers risk their lives to protect gorillas – and how it's working Why did those giant rats go extinct? And could they come back? 'Extinct' Omura's whales spotted: How rare are they? 10,000-year-old lion cubs found frozen in Siberia offer link to distant past Share this article Copy link Link copied. ×
From blue whales to elephants, most of the world’s most massive species are facing extinction. A new study of fish fossils suggests that when large vertebrates become extinct, evolution does not replace them for many years. Researchers, after analyzing fish that lived about 350 million years ago, have concluded that a mass extinction known as the Hangenberg event caused large species to die off while smaller species survived. "Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine, " said Lauren Sallan, an environmental scientist at the University of Pennsylvania, in a news release. Her findings suggest that the smaller fish had a unique advantage over their larger counterparts: they breed much, much faster than their giant cousins. "The end result is an ocean in which most sharks are less than a meter [three feet] and most fishes and tetrapods are less than 10 centimeters," or smaller than a grapefruit, said Dr. Sallen. "Yet these are the ancestors of everything that dominates from then on, including humans." Recommended 14 animals declared extinct in the 21st century Paleontologists have long debated the changes in the body sizes of animals over time. One theory, known as Cope's rule, says a species tends to enlarge over time to avoid predation and to become better hunters. Another theory says that all things being equal, animals become larger in the presence of increased oxygen, or in colder climates. Another idea, known as the Lilliput Effect, holds that after mass extinctions, there will inevitably be a temporary trend toward small body size. It’s named after a fictional island in the book “Gulliver’s Travels” that’s inhabited by tiny people. Many scientists believe that we are on the brink of – if not in the midst of – a sixth mass extinction . This summer, scientists released a report indicating that humans are chiefly to blame for the mass extinction that is already underway. Recommended 14 animals declared extinct in the 21st century But these same scientists say that aggressive conservation efforts may yet stave off a true mass extinction. Humpback whales, for example, were recently recommended for removal from the endangered species list . "This will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations – notably habitat loss, overexploitation for economic gain, and climate change," wrote the research team, including scientists from Stanford, Princeton, and Berkeley, in their report . Get stories that empower and uplift daily. By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . If the present extinction does eliminate the planet's largest animals, the new study suggests they will not be replaced any time soon. "It doesn't matter what is eliminating the large fish or what is making ecosystems unstable," Sallan said. "These disturbances are shifting natural selection so that smaller, faster-reproducing fish are more likely to keep going, and it could take a really long time to get those bigger fish back in any sizable way." You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe
From blue whales to elephants, most of the world’s most massive species are facing extinction. A new study of fish fossils suggests that when large vertebrates become extinct, evolution does not replace them for many years. Researchers, after analyzing fish that lived about 350 million years ago, have concluded that a mass extinction known as the Hangenberg event caused large species to die off while smaller species survived. "Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine, " said Lauren Sallan, an environmental scientist at the University of Pennsylvania, in a news release. Her findings suggest that the smaller fish had a unique advantage over their larger counterparts: they breed much, much faster than their giant cousins. "The end result is an ocean in which most sharks are less than a meter [three feet] and most fishes and tetrapods are less than 10 centimeters," or smaller than a grapefruit, said Dr. Sallen. "Yet these are the ancestors of everything that dominates from then on, including humans." Recommended 14 animals declared extinct in the 21st century Paleontologists have long debated the changes in the body sizes of animals over time. One theory, known as Cope's rule, says a species tends to enlarge over time to avoid predation and to become better hunters. Another theory says that all things being equal, animals become larger in the presence of increased oxygen, or in colder climates. Another idea, known as the Lilliput Effect, holds that after mass extinctions, there will inevitably be a temporary trend toward small body size. It’s named after a fictional island in the book “Gulliver’s Travels” that’s inhabited by tiny people. Many scientists believe that we are on the brink of – if not in the midst of – a sixth mass extinction . This summer, scientists released a report indicating that humans are chiefly to blame for the mass extinction that is already underway. Recommended 14 animals declared extinct in the 21st century But these same scientists say that aggressive conservation efforts may yet stave off a true mass extinction. Humpback whales, for example, were recently recommended for removal from the endangered species list . "This will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations – notably habitat loss, overexploitation for economic gain, and climate change," wrote the research team, including scientists from Stanford, Princeton, and Berkeley, in their report . Get stories that empower and uplift daily. By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . If the present extinction does eliminate the planet's largest animals, the new study suggests they will not be replaced any time soon. "It doesn't matter what is eliminating the large fish or what is making ecosystems unstable," Sallan said. "These disturbances are shifting natural selection so that smaller, faster-reproducing fish are more likely to keep going, and it could take a really long time to get those bigger fish back in any sizable way." You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe
From blue whales to elephants, most of the world’s most massive species are facing extinction. A new study of fish fossils suggests that when large vertebrates become extinct, evolution does not replace them for many years. Researchers, after analyzing fish that lived about 350 million years ago, have concluded that a mass extinction known as the Hangenberg event caused large species to die off while smaller species survived. "Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine, " said Lauren Sallan, an environmental scientist at the University of Pennsylvania, in a news release. Her findings suggest that the smaller fish had a unique advantage over their larger counterparts: they breed much, much faster than their giant cousins. "The end result is an ocean in which most sharks are less than a meter [three feet] and most fishes and tetrapods are less than 10 centimeters," or smaller than a grapefruit, said Dr. Sallen. "Yet these are the ancestors of everything that dominates from then on, including humans." Recommended 14 animals declared extinct in the 21st century Paleontologists have long debated the changes in the body sizes of animals over time. One theory, known as Cope's rule, says a species tends to enlarge over time to avoid predation and to become better hunters. Another theory says that all things being equal, animals become larger in the presence of increased oxygen, or in colder climates. Another idea, known as the Lilliput Effect, holds that after mass extinctions, there will inevitably be a temporary trend toward small body size. It’s named after a fictional island in the book “Gulliver’s Travels” that’s inhabited by tiny people. Many scientists believe that we are on the brink of – if not in the midst of – a sixth mass extinction . This summer, scientists released a report indicating that humans are chiefly to blame for the mass extinction that is already underway. Recommended 14 animals declared extinct in the 21st century But these same scientists say that aggressive conservation efforts may yet stave off a true mass extinction. Humpback whales, for example, were recently recommended for removal from the endangered species list . "This will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations – notably habitat loss, overexploitation for economic gain, and climate change," wrote the research team, including scientists from Stanford, Princeton, and Berkeley, in their report . Get stories that empower and uplift daily. By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . If the present extinction does eliminate the planet's largest animals, the new study suggests they will not be replaced any time soon. "It doesn't matter what is eliminating the large fish or what is making ecosystems unstable," Sallan said. "These disturbances are shifting natural selection so that smaller, faster-reproducing fish are more likely to keep going, and it could take a really long time to get those bigger fish back in any sizable way."
A new study of fish fossils suggests that when large vertebrates become extinct, evolution does not replace them for many years.
Researchers, after analyzing fish that lived about 350 million years ago, have concluded that a mass extinction known as the Hangenberg event caused large species to die off while smaller species survived.
"Rather than having this thriving ecosystem of large things, you may have one gigantic relict, but otherwise everything is the size of a sardine, " said Lauren Sallan, an environmental scientist at the University of Pennsylvania, in a news release.
Her findings suggest that the smaller fish had a unique advantage over their larger counterparts: they breed much, much faster than their giant cousins.
"The end result is an ocean in which most sharks are less than a meter [three feet] and most fishes and tetrapods are less than 10 centimeters," or smaller than a grapefruit, said Dr. Sallen. "Yet these are the ancestors of everything that dominates from then on, including humans."
One theory, known as Cope's rule, says a species tends to enlarge over time to avoid predation and to become better hunters.
Another theory says that all things being equal, animals become larger in the presence of increased oxygen, or in colder climates.
Another idea, known as the Lilliput Effect, holds that after mass extinctions, there will inevitably be a temporary trend toward small body size. It’s named after a fictional island in the book “Gulliver’s Travels” that’s inhabited by tiny people.
Many scientists believe that we are on the brink of – if not in the midst of – a sixth mass extinction . This summer, scientists released a report indicating that humans are chiefly to blame for the mass extinction that is already underway.
But these same scientists say that aggressive conservation efforts may yet stave off a true mass extinction. Humpback whales, for example, were recently recommended for removal from the endangered species list .
"This will require rapid, greatly intensified efforts to conserve already threatened species and to alleviate pressures on their populations – notably habitat loss, overexploitation for economic gain, and climate change," wrote the research team, including scientists from Stanford, Princeton, and Berkeley, in their report .
Get stories that empower and uplift daily. By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads .
If the present extinction does eliminate the planet's largest animals, the new study suggests they will not be replaced any time soon.
"It doesn't matter what is eliminating the large fish or what is making ecosystems unstable," Sallan said. "These disturbances are shifting natural selection so that smaller, faster-reproducing fish are more likely to keep going, and it could take a really long time to get those bigger fish back in any sizable way."
You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe
You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe
You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe
You've read of free articles. Subscribe to continue. Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe
Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe
Help fund Monitor journalism for $11/ month Already a subscriber? Login Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support. Subscribe
Mark Sappenfield Editor Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support.
Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations. Our work isn't possible without your support.
Monitor journalism changes lives because we open that too-small box that most people think they live in. We believe news can and should expand a sense of identity and possibility beyond narrow conventional expectations.
Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe
Unlimited digital access $11/month. Already a subscriber? Login Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime. Subscribe
Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime.
Digital subscription includes: Unlimited access to CSMonitor.com. CSMonitor.com archive. The Monitor Daily email. No advertising. Cancel anytime.
Real news can be honest, hopeful, credible, constructive. What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world. Mark Sappenfield , Editor [email protected] Subscribe
Real news can be honest, hopeful, credible, constructive. What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world. Mark Sappenfield , Editor [email protected] Subscribe
Real news can be honest, hopeful, credible, constructive. What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world. Mark Sappenfield , Editor [email protected] Subscribe
What is the Monitor difference? Tackling the tough headlines – with humanity. Listening to sources – with respect. Seeing the story that others are missing by reporting what so often gets overlooked: the values that connect us. That’s Monitor reporting – news that changes how you see the world.
Related stories Test your knowledge Name that animal! First Look From hypercarnivores to megafauna: How huge animals shaped their world Global News Blog Why park rangers risk their lives to protect gorillas – and how it's working Why did those giant rats go extinct? And could they come back? 'Extinct' Omura's whales spotted: How rare are they? 10,000-year-old lion cubs found frozen in Siberia offer link to distant past Share this article Copy link Link copied. ×
Related stories Test your knowledge Name that animal! First Look From hypercarnivores to megafauna: How huge animals shaped their world Global News Blog Why park rangers risk their lives to protect gorillas – and how it's working Why did those giant rats go extinct? And could they come back? 'Extinct' Omura's whales spotted: How rare are they? 10,000-year-old lion cubs found frozen in Siberia offer link to distant past Share this article Copy link Link copied. ×
Related stories Test your knowledge Name that animal! First Look From hypercarnivores to megafauna: How huge animals shaped their world Global News Blog Why park rangers risk their lives to protect gorillas – and how it's working Why did those giant rats go extinct? And could they come back? 'Extinct' Omura's whales spotted: How rare are they? 10,000-year-old lion cubs found frozen in Siberia offer link to distant past
Mark Sappenfield Editor Dear Reader, About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”: “Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.” If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism. But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in. The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908. We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.” If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com. Subscribe to insightful journalism
Mark Sappenfield Editor Dear Reader, About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”: “Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.” If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism. But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in. The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908. We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.” If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com. Subscribe to insightful journalism
Dear Reader, About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”: “Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.” If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism. But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in. The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908. We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.” If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.
About a year ago, I happened upon this statement about the Monitor in the Harvard Business Review – under the charming heading of “do things that don’t interest you”:
“Many things that end up” being meaningful, writes social scientist Joseph Grenny, “have come from conference workshops, articles, or online videos that began as a chore and ended with an insight. My work in Kenya, for example, was heavily influenced by a Christian Science Monitor article I had forced myself to read 10 years earlier. Sometimes, we call things ‘boring’ simply because they lie outside the box we are currently in.”
If you were to come up with a punchline to a joke about the Monitor, that would probably be it. We’re seen as being global, fair, insightful, and perhaps a bit too earnest. We’re the bran muffin of journalism.
But you know what? We change lives. And I’m going to argue that we change lives precisely because we force open that too-small box that most human beings think they live in.
The Monitor is a peculiar little publication that’s hard for the world to figure out. We’re run by a church, but we’re not only for church members and we’re not about converting people. We’re known as being fair even as the world becomes as polarized as at any time since the newspaper’s founding in 1908.
We have a mission beyond circulation, we want to bridge divides. We’re about kicking down the door of thought everywhere and saying, “You are bigger and more capable than you realize. And we can prove it.”
If you’re looking for bran muffin journalism, you can subscribe to the Monitor for $15. You’ll get the Monitor Weekly magazine, the Monitor Daily email, and unlimited access to CSMonitor.com.
Read this article in https://www.csmonitor.com/Science/2015/1114/Small-animals-thrive-after-mass-extinctions-say-scientists Start your subscription today https://www.csmonitor.com/subscribe
Read this article in https://www.csmonitor.com/Science/2015/1114/Small-animals-thrive-after-mass-extinctions-say-scientists
Read this article in https://www.csmonitor.com/Science/2015/1114/Small-animals-thrive-after-mass-extinctions-say-scientists
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close ×
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy . Already a subscriber? Log in to hide ads . Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close ×
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy .
Get stories that empower and uplift daily. See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy .
See our other FREE newsletters . Your email address By signing up, you agree to our Privacy Policy .
Select free newsletters: The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional Today's Highlights Select stories from the Monitor that empower and uplift. Every Weekday Politics An update on major political events, candidates, and parties twice a week. Twice a Week Science & Nature Stay informed about the latest scientific discoveries & breakthroughs. Every Tuesday Commentary A weekly digest of Monitor views and insightful commentary on major events. Every Thursday Books Latest book reviews, author interviews, and reading trends. Every Friday Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday Close ×
The Weekender A selection of the most viewed stories this week on the Monitor's website. Every Saturday
Announcements Hear about special editorial projects, new product information, and upcoming events. Occasional
Culture & Learning A weekly update on music, movies, cultural trends, and education solutions. Every Thursday
Christian Science Perspective The three most recent Christian Science articles with a spiritual perspective. Every Monday
About Contact Us Subscribe Give a Gift Subscription Support Monitor Journalism Free Newsletters Careers Social Media Community Connect Content Map Text Edition RSS Reprints & Permissions Multimedia A Christian Science Perspective
Social Media Community Connect Content Map Text Edition RSS Reprints & Permissions Multimedia A Christian Science Perspective
This website uses cookies to improve functionality and performance. By continuing to browse the site you are agreeing to our use of cookies . Close | biology | 998 | https://da.wikipedia.org/wiki/Art | Art | Arten (species, forkortet sp., flertal: spp.) er den grundlæggende systematiske enhed inden for biologien. Arten defineres ofte som en naturlig gruppe af populationer, hvor udveksling af gener finder sted (eller kan finde sted) og som i forhold til forplantning er isoleret fra andre grupper. Det vil sige at kun individer inden for samme art kan parre sig og få forplantningsdygtigt afkom. Dette kaldes det biologiske artsbegreb. For organismer, der formerer sig ukønnet eller ved selvbestøvning, må arter afgrænses ud fra ligheder og forskelle mellem forskellige individer. Nogle dyrearter kan i fangenskab hybridisere og få fertilt afkom, men da dette ikke vil ske i naturen, selv om de mødes her, betragtes de som forskellige arter.
Eksempel
To heste kan parre sig og få et føl, der igen kan få føl med andre heste – hestene tilhører derfor samme art. En hest og et æsel kan også parre sig og deres unger kaldes enten muldyr eller mulæsel, afhængig af hvem der er moren, men muldyret eller mulæselet kan (normalt) ikke få unger, da de oftest er sterile. Af den grund regnes hest og æsel som to forskellige arter. Det samme princip gælder også for planterne. Denne naturskabte afgrænsning mellem to arter kaldes en artsbarriere. Den kan af og til gennembrydes, når ellers sterile krydsninger spontant eller kunstigt får gennemført en kromosomfordobling. Se f.eks. Vadegræs (Spartina pectinata).
Arter over for hybrider
Man kan dog godt komme ud for, at arter kan krydses og får blandet afkom, men hybriden vil kun kunne bestå på steder, hvor ingen af forældrearterne kan klare sig. Dette er et særligt udpræget problem med Rododendron (Rhododendron) og Tjørn (Crataegus), fordi disse slægter breder sig voldsomt efter skovbrand eller stormfald. Da hybriderne bliver frugtbare i en yngre alder end arterne, kan de dominere i en periode, men når skoven lukker sig, så fortrænges hybriderne og kun de specialiserede arter kan overleve i skovens dybe skygge eller ude i lyset i sumpe, på ur og i kalksten, m.m.
Flere artsbegreber
Fordi det biologiske artsbegreb kan være besværligt at anvende i praksis, er der efterhånden skabt en række andre artsbegreber:
Morfologisk artsbegreb Arterne adskiller sig fra hinanden ved deres bygning. Dette begreb er blevet meget anvendt gennem tiden.
Økologisk artsbegreb Definerer en art som en gruppe af organismer, der udfylder samme niche. Krydsninger mellem to nærtstående arter vil ikke være optimalt tilpasset til forældrearternes nicher og vil ikke klare sig i konkurrencen.
Evolutionære artsbegreb Også kaldet det kladistiske eller fylogenetiske artsbegreb. Naturen er dynamisk, ikke statisk - alle arter ændrer sig med tiden og bliver, hvis de ikke uddør som følge af konkurrence, naturkatastrofer m.v., til én eller flere nye arter. Det evolutionære artsbegreb minder om det biologiske, men inddrager tidsdimensionen, det vil sige at en art udvikler sig over tid og at nye arter opstår ved artsdannelse. Individer der fylogenetisk har samme stamfader tilhører samme art.
Pluralistisk artsbegreb En art er et samfund af populationer, der formerer sig og lever inden for en bestemt niche i naturen.
Se også
Systematik
Evolutionsteori
Kilder
Lars Skipper: Hvad er en art? Citat: "...Arten er den eneste [klassifikations-kategori] der eksisterer i virkeligheden, alle andre (slægter, familier, ordener m.v.) er indført for overskuelighedens skyld..."
Eksterne henvisninger
2003-12-31, ScienceDaily: Working On The 'Porsche Of Its Time': New Model For Species Determination Offered Citat: "...two species of dinosaur that are members of the same genera varied from each other by just 2.2 percent. Translation of the percentage into an actual number results in an average of just three skeletal differences out of the total 338 bones in the body. Amazingly, 58 percent of these differences occurred in the skull alone. "This is a lot less variation than I'd expected," said Novak..."
2003-08-08, ScienceDaily: Cross-species Mating May Be Evolutionarily Important And Lead To Rapid Change, Say Indiana University Researchers Citat: "...the sudden mixing of closely related species may occasionally provide the energy to impel rapid evolutionary change..."
2004-01-09 ScienceDaily: Mayo Researchers Observe Genetic Fusion Of Human, Animal Cells; May Help Explain Origin Of AIDS Citat: "...The researchers have discovered conditions in which pig cells and human cells can fuse together in the body to yield hybrid cells that contain genetic material from both species..."What we found was completely unexpected," says Jeffrey Platt, M.D..."
2000-09-18, ScienceDaily: Scientists Unravel Ancient Evolutionary History Of Photosynthesis Citat: "...gene-swapping was common among ancient bacteria early in evolution..."
2004-06-07, Sciencedaily: Parting Genomes: University Of Arizona Biologists Discover Seeds Of Speciation Citat: "...There's a huge amount of biodiversity out there, and we don't know where it comes from. Evolutionary biologists are excited to figure out what causes what we see out there--the relative forces of selection and drift--whether things are adapting to their environment or variation is random..."
2005-07-05, Sciencedaily: Trees, Vines And Nets -- Microbial Evolution Changes Its Face Citat: "... EBI researchers have changed our view of 4 billion years of microbial evolution...In all, more than 600,000 vertical transfers are observed, coupled with 90,000 gene loss events and approximately 40,000 horizontal gene transfers...A few species, including beneficial nitrogen-fixing soil bacteria, appear to be 'champions'of horizontal gene transfer; "it's entirely possible that apparently harmless organisms are quietly spreading antibiotic resistance under our feet," concludes Christos Ouzounis..."
2005-11-11, Sciencedaily: Lateral Thinking Produces First Map Of Gene Transmission Citat: "...Their results clearly show genetic modification of organisms by lateral transfer is a widespread natural phenomenon, and it can occur even between distantly related organisms... it was assumed that transfer of genes could only be vertical, i.e. from parents to offspring..."
Økologi
Biologi | danish | 0.791178 |
animals_evolve_size/.txt |
09-18-2017 Largest and smallest animals at the highest risk of extinction By Eric Ralls Earth.com staff writer Researchers developed a global study to take a closer look at the sizes of endangered vertebrate animal species. An analysis of the body masses of thousands of animals revealed that the largest and smallest species of animals are at a higher risk of extinction than those in between. “Knowing how animal body size correlates with the likelihood of a species being threatened provides us with a tool to assess extinction risk for the many species we know very little about,” said lead author William Ripple of Oregon State University . The research team scrutinized over 27,000 vertebrate animals that had been assessed for the Red List of Threatened Species. Mammals , birds, reptiles, amphibians, bony fishes, and cartilaginous fishes were all evaluated for the study. Approximately 4,400 of the animals observed are threatened with extinction. “Many of the larger species are being killed and consumed by humans, and about 90 percent of all threatened species larger than 2.2 pounds in size are being threatened by harvesting,” said Ripple. “Harvesting of these larger animals takes a variety of forms including regulated and unregulated fishing, hunting and trapping for meat consumption, the use of body parts as medicine and killing due to unintentional bycatch,” explained the authors of the study. The researchers believe that the risks faced by the smallest species are greatly underestimated. The smallest species with high extinction risk consist of tiny vertebrate animals generally less than about 3 ounces in body weight. They are mostly threatened by loss or modification of habitat, and small species that require freshwater habitats are the most at risk. Some of the smaller species that are threatened include the Clarke’s banana frog, sapphire-bellied hummingbird, gray gecko, hog-nosed bat and the waterfall climbing cave fish. The authors said that different conservation strategies will be needed to face the threats to the largest and smallest animals. While some large mammals such as whales, elephants, rhinos, and lions are well known and get more attention, conservation is also needed for large-bodied species that are not mammals such as large fish, birds, amphibians and reptiles. The research is published in the Proceedings of the National Academy of Sciences . — By Chrissy Sexton , Earth.com Staff Writer RELATED NEWS 04-29-2024 Lifespan is influenced more by lifestyle than genetics 04-29-2024 Future forests: Which tree species can survive climate change? 04-29-2024 Frequent vaping exposes teens to toxic metals 04-29-2024 Dolphin in Florida tests positive for avian influenza 04-29-2024 What are the biggest drivers of biodiversity loss? 04-29-2024 Healthy diet linked to positive changes in brain structure 04-29-2024 Nighttime buzz: Insect activity increases by 31.4% at night 04-29-2024 Hornets are the most important pollinators for some plants 04-29-2024 Global measles crisis: Cases nearly doubled in 2023 04-29-2024 Dinosaurs were less intelligent than modern day monkeys 04-29-2024 Forgetting things is a natural part of the memory process 04-29-2024 Arctic warming impacts dust levels on a global scale News coming your way The biggest news about our planet delivered to you each day SUBSCRIBE
09-18-2017 Largest and smallest animals at the highest risk of extinction By Eric Ralls Earth.com staff writer Researchers developed a global study to take a closer look at the sizes of endangered vertebrate animal species. An analysis of the body masses of thousands of animals revealed that the largest and smallest species of animals are at a higher risk of extinction than those in between. “Knowing how animal body size correlates with the likelihood of a species being threatened provides us with a tool to assess extinction risk for the many species we know very little about,” said lead author William Ripple of Oregon State University . The research team scrutinized over 27,000 vertebrate animals that had been assessed for the Red List of Threatened Species. Mammals , birds, reptiles, amphibians, bony fishes, and cartilaginous fishes were all evaluated for the study. Approximately 4,400 of the animals observed are threatened with extinction. “Many of the larger species are being killed and consumed by humans, and about 90 percent of all threatened species larger than 2.2 pounds in size are being threatened by harvesting,” said Ripple. “Harvesting of these larger animals takes a variety of forms including regulated and unregulated fishing, hunting and trapping for meat consumption, the use of body parts as medicine and killing due to unintentional bycatch,” explained the authors of the study. The researchers believe that the risks faced by the smallest species are greatly underestimated. The smallest species with high extinction risk consist of tiny vertebrate animals generally less than about 3 ounces in body weight. They are mostly threatened by loss or modification of habitat, and small species that require freshwater habitats are the most at risk. Some of the smaller species that are threatened include the Clarke’s banana frog, sapphire-bellied hummingbird, gray gecko, hog-nosed bat and the waterfall climbing cave fish. The authors said that different conservation strategies will be needed to face the threats to the largest and smallest animals. While some large mammals such as whales, elephants, rhinos, and lions are well known and get more attention, conservation is also needed for large-bodied species that are not mammals such as large fish, birds, amphibians and reptiles. The research is published in the Proceedings of the National Academy of Sciences . — By Chrissy Sexton , Earth.com Staff Writer RELATED NEWS 04-29-2024 Lifespan is influenced more by lifestyle than genetics 04-29-2024 Future forests: Which tree species can survive climate change? 04-29-2024 Frequent vaping exposes teens to toxic metals 04-29-2024 Dolphin in Florida tests positive for avian influenza 04-29-2024 What are the biggest drivers of biodiversity loss? 04-29-2024 Healthy diet linked to positive changes in brain structure 04-29-2024 Nighttime buzz: Insect activity increases by 31.4% at night 04-29-2024 Hornets are the most important pollinators for some plants 04-29-2024 Global measles crisis: Cases nearly doubled in 2023 04-29-2024 Dinosaurs were less intelligent than modern day monkeys 04-29-2024 Forgetting things is a natural part of the memory process 04-29-2024 Arctic warming impacts dust levels on a global scale
09-18-2017 Largest and smallest animals at the highest risk of extinction By Eric Ralls Earth.com staff writer Researchers developed a global study to take a closer look at the sizes of endangered vertebrate animal species. An analysis of the body masses of thousands of animals revealed that the largest and smallest species of animals are at a higher risk of extinction than those in between. “Knowing how animal body size correlates with the likelihood of a species being threatened provides us with a tool to assess extinction risk for the many species we know very little about,” said lead author William Ripple of Oregon State University . The research team scrutinized over 27,000 vertebrate animals that had been assessed for the Red List of Threatened Species. Mammals , birds, reptiles, amphibians, bony fishes, and cartilaginous fishes were all evaluated for the study. Approximately 4,400 of the animals observed are threatened with extinction. “Many of the larger species are being killed and consumed by humans, and about 90 percent of all threatened species larger than 2.2 pounds in size are being threatened by harvesting,” said Ripple. “Harvesting of these larger animals takes a variety of forms including regulated and unregulated fishing, hunting and trapping for meat consumption, the use of body parts as medicine and killing due to unintentional bycatch,” explained the authors of the study. The researchers believe that the risks faced by the smallest species are greatly underestimated. The smallest species with high extinction risk consist of tiny vertebrate animals generally less than about 3 ounces in body weight. They are mostly threatened by loss or modification of habitat, and small species that require freshwater habitats are the most at risk. Some of the smaller species that are threatened include the Clarke’s banana frog, sapphire-bellied hummingbird, gray gecko, hog-nosed bat and the waterfall climbing cave fish. The authors said that different conservation strategies will be needed to face the threats to the largest and smallest animals. While some large mammals such as whales, elephants, rhinos, and lions are well known and get more attention, conservation is also needed for large-bodied species that are not mammals such as large fish, birds, amphibians and reptiles. The research is published in the Proceedings of the National Academy of Sciences . — By Chrissy Sexton , Earth.com Staff Writer RELATED NEWS 04-29-2024 Lifespan is influenced more by lifestyle than genetics 04-29-2024 Future forests: Which tree species can survive climate change? 04-29-2024 Frequent vaping exposes teens to toxic metals 04-29-2024 Dolphin in Florida tests positive for avian influenza 04-29-2024 What are the biggest drivers of biodiversity loss? 04-29-2024 Healthy diet linked to positive changes in brain structure 04-29-2024 Nighttime buzz: Insect activity increases by 31.4% at night 04-29-2024 Hornets are the most important pollinators for some plants 04-29-2024 Global measles crisis: Cases nearly doubled in 2023 04-29-2024 Dinosaurs were less intelligent than modern day monkeys 04-29-2024 Forgetting things is a natural part of the memory process 04-29-2024 Arctic warming impacts dust levels on a global scale
09-18-2017 Largest and smallest animals at the highest risk of extinction By Eric Ralls Earth.com staff writer Researchers developed a global study to take a closer look at the sizes of endangered vertebrate animal species. An analysis of the body masses of thousands of animals revealed that the largest and smallest species of animals are at a higher risk of extinction than those in between. “Knowing how animal body size correlates with the likelihood of a species being threatened provides us with a tool to assess extinction risk for the many species we know very little about,” said lead author William Ripple of Oregon State University . The research team scrutinized over 27,000 vertebrate animals that had been assessed for the Red List of Threatened Species. Mammals , birds, reptiles, amphibians, bony fishes, and cartilaginous fishes were all evaluated for the study. Approximately 4,400 of the animals observed are threatened with extinction. “Many of the larger species are being killed and consumed by humans, and about 90 percent of all threatened species larger than 2.2 pounds in size are being threatened by harvesting,” said Ripple. “Harvesting of these larger animals takes a variety of forms including regulated and unregulated fishing, hunting and trapping for meat consumption, the use of body parts as medicine and killing due to unintentional bycatch,” explained the authors of the study. The researchers believe that the risks faced by the smallest species are greatly underestimated. The smallest species with high extinction risk consist of tiny vertebrate animals generally less than about 3 ounces in body weight. They are mostly threatened by loss or modification of habitat, and small species that require freshwater habitats are the most at risk. Some of the smaller species that are threatened include the Clarke’s banana frog, sapphire-bellied hummingbird, gray gecko, hog-nosed bat and the waterfall climbing cave fish. The authors said that different conservation strategies will be needed to face the threats to the largest and smallest animals. While some large mammals such as whales, elephants, rhinos, and lions are well known and get more attention, conservation is also needed for large-bodied species that are not mammals such as large fish, birds, amphibians and reptiles. The research is published in the Proceedings of the National Academy of Sciences . — By Chrissy Sexton , Earth.com Staff Writer
Researchers developed a global study to take a closer look at the sizes of endangered vertebrate animal species. An analysis of the body masses of thousands of animals revealed that the largest and smallest species of animals are at a higher risk of extinction than those in between. “Knowing how animal body size correlates with the likelihood of a species being threatened provides us with a tool to assess extinction risk for the many species we know very little about,” said lead author William Ripple of Oregon State University . The research team scrutinized over 27,000 vertebrate animals that had been assessed for the Red List of Threatened Species. Mammals , birds, reptiles, amphibians, bony fishes, and cartilaginous fishes were all evaluated for the study. Approximately 4,400 of the animals observed are threatened with extinction. “Many of the larger species are being killed and consumed by humans, and about 90 percent of all threatened species larger than 2.2 pounds in size are being threatened by harvesting,” said Ripple. “Harvesting of these larger animals takes a variety of forms including regulated and unregulated fishing, hunting and trapping for meat consumption, the use of body parts as medicine and killing due to unintentional bycatch,” explained the authors of the study. The researchers believe that the risks faced by the smallest species are greatly underestimated. The smallest species with high extinction risk consist of tiny vertebrate animals generally less than about 3 ounces in body weight. They are mostly threatened by loss or modification of habitat, and small species that require freshwater habitats are the most at risk. Some of the smaller species that are threatened include the Clarke’s banana frog, sapphire-bellied hummingbird, gray gecko, hog-nosed bat and the waterfall climbing cave fish. The authors said that different conservation strategies will be needed to face the threats to the largest and smallest animals. While some large mammals such as whales, elephants, rhinos, and lions are well known and get more attention, conservation is also needed for large-bodied species that are not mammals such as large fish, birds, amphibians and reptiles. The research is published in the Proceedings of the National Academy of Sciences . — By Chrissy Sexton , Earth.com Staff Writer
Researchers developed a global study to take a closer look at the sizes of endangered vertebrate animal species. An analysis of the body masses of thousands of animals revealed that the largest and smallest species of animals are at a higher risk of extinction than those in between.
Researchers developed a global study to take a closer look at the sizes of endangered vertebrate animal species. An analysis of the body masses of thousands of animals revealed that the largest and smallest species of animals are at a higher risk of extinction than those in between.
“Knowing how animal body size correlates with the likelihood of a species being threatened provides us with a tool to assess extinction risk for the many species we know very little about,” said lead author William Ripple of Oregon State University .
“Knowing how animal body size correlates with the likelihood of a species being threatened provides us with a tool to assess extinction risk for the many species we know very little about,” said lead author William Ripple of
The research team scrutinized over 27,000 vertebrate animals that had been assessed for the Red List of Threatened Species. Mammals , birds, reptiles, amphibians, bony fishes, and cartilaginous fishes were all evaluated for the study. Approximately 4,400 of the animals observed are threatened with extinction.
The research team scrutinized over 27,000 vertebrate animals that had been assessed for the Red List of Threatened Species. Mammals , birds, reptiles, amphibians, bony fishes, and cartilaginous fishes were all evaluated for the study. Approximately 4,400 of the animals observed are threatened with extinction.
“Many of the larger species are being killed and consumed by humans, and about 90 percent of all threatened species larger than 2.2 pounds in size are being threatened by harvesting,” said Ripple.
“Many of the larger species are being killed and consumed by humans, and about 90 percent of all threatened species larger than 2.2 pounds in size are being threatened by harvesting,” said Ripple.
“Harvesting of these larger animals takes a variety of forms including regulated and unregulated fishing, hunting and trapping for meat consumption, the use of body parts as medicine and killing due to unintentional bycatch,” explained the authors of the study.
“Harvesting of these larger animals takes a variety of forms including regulated and unregulated fishing, hunting and trapping for meat consumption, the use of body parts as medicine and killing due to unintentional bycatch,” explained the authors of the study.
The researchers believe that the risks faced by the smallest species are greatly underestimated. The smallest species with high extinction risk consist of tiny vertebrate animals generally less than about 3 ounces in body weight. They are mostly threatened by loss or modification of habitat, and small species that require freshwater habitats are the most at risk.
The researchers believe that the risks faced by the smallest species are greatly underestimated. The smallest species with high extinction risk consist of tiny vertebrate animals generally less than about 3 ounces in body weight. They are mostly threatened by loss or modification of habitat, and small species that require freshwater habitats are the most at risk.
Some of the smaller species that are threatened include the Clarke’s banana frog, sapphire-bellied hummingbird, gray gecko, hog-nosed bat and the waterfall climbing cave fish.
Some of the smaller species that are threatened include the Clarke’s banana frog, sapphire-bellied hummingbird, gray gecko, hog-nosed bat and the waterfall climbing cave fish.
The authors said that different conservation strategies will be needed to face the threats to the largest and smallest animals. While some large mammals such as whales, elephants, rhinos, and lions are well known and get more attention, conservation is also needed for large-bodied species that are not mammals such as large fish, birds, amphibians and reptiles.
The authors said that different conservation strategies will be needed to face the threats to the largest and smallest animals. While some large mammals such as whales, elephants, rhinos, and lions are well known and get more attention, conservation is also needed for large-bodied species that are not mammals such as large fish, birds, amphibians and reptiles.
RELATED NEWS 04-29-2024 Lifespan is influenced more by lifestyle than genetics 04-29-2024 Future forests: Which tree species can survive climate change? 04-29-2024 Frequent vaping exposes teens to toxic metals 04-29-2024 Dolphin in Florida tests positive for avian influenza 04-29-2024 What are the biggest drivers of biodiversity loss? 04-29-2024 Healthy diet linked to positive changes in brain structure 04-29-2024 Nighttime buzz: Insect activity increases by 31.4% at night 04-29-2024 Hornets are the most important pollinators for some plants 04-29-2024 Global measles crisis: Cases nearly doubled in 2023 04-29-2024 Dinosaurs were less intelligent than modern day monkeys 04-29-2024 Forgetting things is a natural part of the memory process 04-29-2024 Arctic warming impacts dust levels on a global scale
About Us Privacy Policy Terms of Service Site Map Staff EARTH.COM News Videos Images Earthpedia Take action EARTHPEDIA Articles Animals Encyclopedia Endangered Animals Plants Encyclopedia Endangered Plants EARTH NEWS Breaking News Environment Lifesyle Voices Animals Plants GET IN TOUCH Contact Us © 2024 Earth.com All rights reserved
About Us Privacy Policy Terms of Service Site Map Staff EARTH.COM News Videos Images Earthpedia Take action EARTHPEDIA Articles Animals Encyclopedia Endangered Animals Plants Encyclopedia Endangered Plants EARTH NEWS Breaking News Environment Lifesyle Voices Animals Plants GET IN TOUCH Contact Us © 2024 Earth.com All rights reserved | biology | 57173 | https://sv.wikipedia.org/wiki/Domesticering | Domesticering | Domesticering är människans förädling av från början vilda arter genom avel.
Genom mänsklig påverkan har ett antal djur- eller växtarter förändrats från vild form till av människan mer eller mindre beroende underarter. Exempel på detta är hundar, nötboskap, hästar, grisar, vete, ris med flera från början vilda arter. Hos en fullständigt domesticerad art styrs urvalet helt av människan, och växten eller djuret har anpassats till människans behov.
Domesticering av djur ska skiljas från tämjning, som innebär att en individ anpassas till att följa en mänsklig social hierarki. Tamkatter är domesticerade men svårare att tämja än hundar och hovdjur.
Hunden blev det första djuret som människor domesticerade. Hundens förfader är vargen som antas ha följt efter människor och ätit det människor slängde, människor i sin tur märkte att vargarna kunde varna om fara hotade, till exempel björnar eller annat farligt i närheten. Efter hunden domesticerades geten, fåret och sedan grisen.
Domesticering av djur
Enligt evolutionsbiologen Jared Diamond måste en djurart uppfylla sex kriterier för att kunna domesticeras.
Flexibel diet – Djur som kan äta av många olika födokällor kan leva på mat som finns längre ned i näringspyramiden och är billigare att föda upp. Framförallt om de äter sådant som människan inte utnyttjar alls, till exempel gräs. Köttätare äter av naturen endast kött, och förbrukar därmed andra djur, dock kan de kanske äta kött från källor som människan inte utnyttjar, till exempel slakterirester och skadedjur.
Rimligt snabb generationstid – Djur som relativt till den mänskliga livstiden snabbt uppnår fertil ålder möjliggör synliga framsteg på avel och kräver inte så lång tid med vilda djur. Detta har hindrat domesticeringen av elefanter.
Förmåga att kunna avlas selektivt i fångenskap – Djur som är motvilliga att para sig i fångenskap ger ingen användbar avkomma, utan vilda djur måste hela tiden fångas.
Vänligt humör – Stora djur som är aggressiva mot människor är farliga att hålla i fångenskap. Detta har bland annat hindrat domesticeringen av björnar.
Temperament som normalt inte innehåller panik – Ett nervöst djur är svårt att hålla i fångenskap eftersom det kommer att försöka fly närhelst det blir skrämt. Gaseller är ett exempel på detta, men även får har en stark tendens att gripas av panik när något närmar sig. Däremot har får en tendens att inte lämna flocken, vilket gör dem lätta att valla med hundar eller människor.
Social hierarki som kan modifieras – Sociala djur som följer en hierarki kan uppfostras att betrakta människor som flockledare.
Grad av domesticering
På grund av elefanters långsamma generationsväxlingar blir gränsen mellan den vilda populationen och den tama vag. Liknande problem uppstår när tamkatter förvildas. Ett system för att klassificera domesticeringsgraden ser ut enligt följande:
Vild: Dessa populationer lever hela livet utan mänsklig påverkan.
Uppfödd i fångenskap (i djurparker eller botaniska trädgårdar): Dessa populationer får sin näring genom mänsklig försorg, men går inte att skilja från den vilda populationen i fråga om utseende eller beteende.
Uppfödd kommersiellt: Dessa populationer hålls i stora populationer för att utgöra varor, mat eller husdjur men är inte särskilt förändrade i sitt beteende eller utseende. Exempel på detta är elefanter, strutsar, hjortar, alligatorer och pärlmusslor. Denna grupp kallas ibland delvis domesticerad.
Domesticerad: Dessa populationer har fötts upp med mänsklig kontroll i många generationer och är avsevärt förändrade i beteende eller utseende. Exempel ur denna grupp är kanariefåglar, undulater, hundar, katter, får, boskap, höns och marsvin
Den klassificering som beskrivs ovan tar inte hänsyn till ett antal komplicerande faktorer: genetiskt modifierade organismer, vilda populationer och hybrider. Många arter som traditionellt används inom jordbruket utsätts nu för genetisk modifiering. Dessa arter bildar en ny kategori eftersom egenskaperna förändras, men inte på samma sätt som traditionell domesticering. Förvildade organismer har tidigare varit kontrollerade av människan, men lever nu vilt. Exempel på detta är mustanger. Hybrider kan vara vilda, domesticerade eller både och: en liger är avkomman av en lejonhane och en tigerhona; två vilda djur, en mula är avkomman av en häst och en åsna; två domesticerade djur, och en beefalo är avkomman av ett nötkreatur och en bisonoxe; en domesticerad och en vild art.
Det finns en betydande skillnad mellan begreppen tam och domesticerad. Domesticerad avser en hel art eller ras, medan tam kan vara en enskild individ. Människan har tämjt tusentals djur som aldrig blivit domesticerade. Till dessa kan elefanter, giraffer och björnar räknas. Likaså finns det exempel på djurarter som är domesticerade, men ändå i egentlig mening inte tama, som honungsbiet.
Ungefärliga tider och platser för domesticering av olika djurarter
Se även
Avel
Vete, vapen och virus
Referenser
Externa länkar
Diskussion om domesticering av djur, University of Houston (engelska)
Nyhet om ett tidigt fynd av domesticerade katter, 2004 (engelska)
Belyaev-experimentet med tamräv (engelska)
Första domesticeringen av Cucurbita pepoi Amerika för 10 000 år sedan (engelska)
Asiatiskt ursprung för en sedan 10 000 år domesticerad växt i Amerika (engelska)
Djurskötsel
Jordbruk
Genetik
Wikipedia:Basartiklar | swedish | 0.734214 |
sense_dimmed_sleep/therelationshipbetwe.txt | [ Home ](/)
About
[ Approach ](https://www.thecenterforconnection.org/approach)
[ Our Team ](https://www.thecenterforconnection.org/therapists)
[ Jobs ](https://www.thecenterforconnection.org/jobs)
[ Contact ](https://www.thecenterforconnection.org/contact)
[ Blog ](/blog)
Services
[ At a Glance ](https://www.thecenterforconnection.org/what-we-offer)
[ Assessments ](https://www.thecenterforconnection.org/testing)
[ Comprehensive Developmental Screenings
](https://www.thecenterforconnection.org/cdscreenings)
[ Educational Care Team ](https://www.thecenterforconnection.org/etatcfc)
[ Events & Groups ](https://www.thecenterforconnection.org/cfc-events-and-
groups)
[ Learning Disabilities & Learning Challenges Clinic ](/ldlcclinic)
[ Mental Health ](https://www.thecenterforconnection.org/mental-health)
[ Occupational Therapy ](https://www.thecenterforconnection.org/ot-home)
[ Parenting Support ](https://www.thecenterforconnection.org/parenting-
support)
[ Play Strong Institute Training and Certifications
](https://www.thecenterforconnection.org/playstrong)
[ Play Therapy ](/mental-health)
[ Presentations & Trainings ](https://www.thecenterforconnection.org/cfc-
speaking1)
[ Safe & Sound Protocol ](https://www.thecenterforconnection.org/safe-sound-
protocol)
[ Speech & Language Therapy ](https://www.thecenterforconnection.org/slp)
New Clients
[ Get Started ](https://www.thecenterforconnection.org/request)
# [ 
](/)
[ Home ](/)
About
[ Approach ](https://www.thecenterforconnection.org/approach)
[ Our Team ](https://www.thecenterforconnection.org/therapists)
[ Jobs ](https://www.thecenterforconnection.org/jobs)
[ Contact ](https://www.thecenterforconnection.org/contact)
[ Blog ](/blog)
Services
[ At a Glance ](https://www.thecenterforconnection.org/what-we-offer)
[ Assessments ](https://www.thecenterforconnection.org/testing)
[ Comprehensive Developmental Screenings
](https://www.thecenterforconnection.org/cdscreenings)
[ Educational Care Team ](https://www.thecenterforconnection.org/etatcfc)
[ Events & Groups ](https://www.thecenterforconnection.org/cfc-events-and-
groups)
[ Learning Disabilities & Learning Challenges Clinic ](/ldlcclinic)
[ Mental Health ](https://www.thecenterforconnection.org/mental-health)
[ Occupational Therapy ](https://www.thecenterforconnection.org/ot-home)
[ Parenting Support ](https://www.thecenterforconnection.org/parenting-
support)
[ Play Strong Institute Training and Certifications
](https://www.thecenterforconnection.org/playstrong)
[ Play Therapy ](/mental-health)
[ Presentations & Trainings ](https://www.thecenterforconnection.org/cfc-
speaking1)
[ Safe & Sound Protocol ](https://www.thecenterforconnection.org/safe-sound-
protocol)
[ Speech & Language Therapy ](https://www.thecenterforconnection.org/slp)
New Clients
[ Get Started ](https://www.thecenterforconnection.org/request)
[ Scott Bryson ](/blogarchive?author=556a7fcce4b0e5c05574a6d9)
[ April 27, 2016 ](/blogarchive/2016/4/27/the-relationship-between-sensory-
processing-and-sleep)
# [ The Relationship between Sensory Processing and Sleep
](/blogarchive/2016/4/27/the-relationship-between-sensory-processing-and-
sleep)
[ Scott Bryson ](/blogarchive?author=556a7fcce4b0e5c05574a6d9)
[ April 27, 2016 ](/blogarchive/2016/4/27/the-relationship-between-sensory-
processing-and-sleep)
by Dr. Jamie Chaves, OTD, OTR/L, SWC
Sleep is a daily occupation in which all of us participate. Some better than
others. When sleep is disrupted this is a red flag for occupational
therapists, and should be for parents and other professionals as well. Sleep
plays a critical role in restoration of brain cells, supporting brain
plasticity, resting muscles and joints, and regulating our circadian rhythm.
Poor sleep negatively impacts almost every area of functioning and
development. Here’s a list of indicators of poor sleep patterns (for children
and adolescents):
*Requires longer than 30-45 minutes to settle before preparing to falling asleep
*Takes longer than 15-20 minutes to fall asleep
*Requires someone present in the room, next to the bed, or lying in bed in order to fall asleep
*Restlessness or frequent changing of positions
*Getting up or waking up at night on a regular basis
*Inconsistent sleep patterns (e.g. sleeps 6 hours one night and 10 hours the next night)
*Gets less than 8 hours of sleep for 3-5 year olds or less than 7 hours of sleep for 6-13 year olds (numbers according to the National Sleep Foundation)
Poor sleep can be an indicator of sensory processing disorder (SPD) for myriad
reasons. Different subtypes of SPD impact sleep differently. Sometimes the
bedtime routine leading up to bedtime is dysregulating, which consequently
impacts the quality of sleep. Sometimes the child is so overstimulated from
the day that settling to sleep can be challenging. Sometimes the
overstimulation from the day is so exhausting to your child that he wants to
nap after school which disrupts his sleep at night. Sometimes the events of
the day were so understimulating that the body was essentially in sleep mode
all day long. It’s important to note that children with unaddressed sensory
processing modulation disorder have a difficult time self-regulating because
they do not yet have the strategies to do so. Therefore co-regulation,
adaptive strategies, and use of external sensory inputs will be necessary
until they can internalize the strategies provided by their occupational
therapist. Don’t be quick to brush off requests or complaints from a child as
“behavioral” or a means to “escape bedtime”.
If your child…
· Doesn’t like the feeling of pajamas (or other specific clothes)
o He/She may be over-responsive to tactile input
o Try sleeping naked, wearing a [ compression shirt
](https://funandfunction.com/special-needs-clothing/shirts.html) to bed, or
wearing an oversized t-shirt to bed
· Doesn’t like the feeling of sheets
o He/She may be over-responsive to tactile input
o Try lycra sheets (“Skweezrs”), using a weighted blanket (7-10% of child’s
body weight)
· Gets upset when bathing or showering
o He/She may be over-responsive to tactile input
o Try bathing or showering in the morning, bathing or showering before
dinner, switching from a shower to a bath
· Wants to sleep next to someone
o He/She may be seeking or under-responsive to proprioceptive input
o Try moving the bed to a corner, buying a body pillow
· Wants stuffed animals or pillows piled on top
o He/She may be seeking or under-responsive to proprioceptive input
o Try sleeping under or on top of a bean bag, using a weighted blanket (7-10%
of child’s body weight)
· Changes positions throughout the night
o He/She may be seeking or under-responsive to vestibular or proprioceptive
input OR over-responsive to tactile input (i.e. the movement is response to
discomfort from pajamas/sheets)
o Try moving the bed to a corner, sleeping under or on top of a bean bag,
using a weighted blanket (7-10% of child’s body weight), lycra sheets
(“Skweezrs”), wearing a [ compression shirt
](https://funandfunction.com/special-needs-clothing/shirts.html) to bed,
wearing an oversized t-shirt to bed
· Falls out of the bed
o He/She may be seeking or under-responsive to vestibular input
o Try moving the bed to a corner, sleeping under or on top of a bean bag,
using a weighted blanket (7-10% of child’s body weight)
· Must have complete silence when falling asleep
o He/She may be over-responsive to auditory input
o Try using a sound machine or white noise machine, wearing [ noise-
cancelling headphones ](http://www.cnet.com/topics/headphones/best-
headphones/noise-canceling/)
· Dislikes the taste of toothpaste
o He/She may be over-responsive to oral (taste/smell) input
o Try brushing without toothpaste at night, using an electric toothbrush,
flavored toothpaste (not peppermint or cinnamon)
· Snacks right before bedtime
o He/She may be seeking oral input
o Try only giving chewy or crunchy foods before bedtime and/or at dinner
· Uses a bottle at bedtime
o He/She may be seeking oral input
o Try giving a piece of candy to suck on when reading in bed, keeping a cup
of water next to the bed, using an electric toothbrush
· Looks around room when falling asleep
o He/She may be seeking visual input
o Try putting in a nightlight, hanging blue or green tube lights, using a [
moving fishtank toy ](http://www.amazon.com/Aquarium-Lamp-Fish-Revolving-
Aquatic/dp/B003WKJJHK/ref=pd_sim_21_4?ie=UTF8&dpID=51ssrZh5rKL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=125E5G1ME8QSBBJPR52R)
· Complains the room is too bright (even with the lights off)
o He/She may be over-responsive to visual input
o Try facing the bed away from the windows, getting heavy curtains for the
windows, using a sleep mask
Poor sleep may also exacerbate sensory processing to the point that child
appears to have SPD. Think about a time you were tired in a meeting or
presentation—what did you do? Oftentimes adults get up to move, swivel in the
chair, bite nails, chew on a pen, drink or eat something, fidget with an
object, doodle on the paper. All of these are sensory strategies to stay awake
and alert. Now think about a time you didn’t sleep well—how did you function
the next day? Did you get up more frequently from your desk? Did you have more
difficulty multi-tasking or remembering details? Did you notice your tolerance
of people around you dropped?
Consider a child who chronically sleeps poorly. Her tiredness may manifest by
constantly jumping or skipping around in an attempt to stay awake. He could
“zone out”. Chewing on his sweatshirt or nails may help him focus. She might
be more reactive towards peers. His frustration tolerance might be limited or
he might give up easily. Spinning in circle could give him more stimulation.
Any strategy to say “wake up, body!” is likely. And anything that tests an
already short fuse will lead to a “zero to sixty” response.
While all children are different in their sleep routine preferences there are
a few things I regularly recommend.
1) Eat dinner early—about 2 ½ hours before bedtime. This will allow for
digestion.
2) Play hard for about 45 minutes before you start the quiet bedtime routine.
3) Transition to the calming routine by dimming the lights and playing
classical instrumental music.
4) Brush teeth. This is usually not a favorite for most kids, so doing it
first will allow for the other activities to re-regulate him/her.
5) Take a warm bath. Showers can be very stimulating because each stream can
feel like a pin prick.
6) Read 2-3 books together in bed.
7) Sing 1-2 songs.
8) Hug and kisses.
9) Lights out.
It’s important to make slow changes to the bedtime routine and to try each
strategy for 1-2 weeks before giving up. Change is hard so it may be met with
initial resistance. Try to get your child involved as much as possible in
making decisions, such as picking the color of the lycra sheets or deciding
where the nightlight should be placed. No matter what, keep your sleep at the
forefront of your conversations until you find a manageable solution!
Tagged: [ occupational therapy ](/blogarchive/tag/occupational+therapy) , [
sleep ](/blogarchive/tag/sleep) , [ sensory processing
](/blogarchive/tag/sensory+processing) , [ OT ](/blogarchive/tag/OT) , [
regulation ](/blogarchive/tag/regulation) , [ kids insomnia
](/blogarchive/tag/kids+insomnia)
Newer Post [ Annalise Kordell talking kids and brains on the radio!
](/blogarchive/2016/7/11/annalise-kordell-talking-kids-and-brains-on-the-
radio)
[ ](https://www.instagram.com/centerforconnection/) [
](https://www.facebook.com/centerforconnection) [ ](https://www.youtube.com/)
[ ](https://www.facebook.com/TinaPayneBrysonPhD/) [
](https://www.instagram.com/tinapaynebryson/) [
](https://twitter.com/tinabryson) [
](https://www.instagram.com/at_the_center/)
Tweets from our Founder, Dr. Tina Payne Bryson, author of _The Whole-Brain
Child_ and other books.
[ Tweets by CFC Founder, Tina Bryson
](https://twitter.com/tinabryson?ref_src=twsrc%5Etfw)
Back to Top
[ At a Glance ](/what-we-offer)
[ CFC Events and Groups ](/cfc-events-and-groups)
[ Assessments: Neuropsychological, Psychological, and Developmental
](/testing)
[ Educational Care Team ](/etatcfc)
[ Comprehensive Child Development Screenings ](/cdscreenings)
[ Learning Disabilities & Learning Challenges Clinic ](/ldlcclinic)
[ Mental Health & Play Therapy ](/mental-health)
[ Occupational Therapy ](/ot-home)
[ Parenting Support ](/parenting-support)
[ Presentations & Training ](/cfc-speaking1)
[ Play Strong Institute Training and Certifications ](/playstrong)
[ Safe & Sound Protocol ](/safe-sound-protocol)
[ Speech & Language Therapy ](/slp)
[ Privacy Policy ](/privacy-notice)
The Center for Connection, 3030 E. Colorado, Suite 214, Pasadena, California,
91107, USA [ [email protected]
](mailto:[email protected])
Powered by [ Squarespace ](http://www.squarespace.com)
| biology | 2904004 | https://sv.wikipedia.org/wiki/Oglasa%20connectens | Oglasa connectens | Oglasa connectens är en fjärilsart som beskrevs av George Francis Hampson 1926. Oglasa connectens ingår i släktet Oglasa och familjen nattflyn. Inga underarter finns listade i Catalogue of Life.
Källor
Nattflyn
connectens | swedish | 1.400434 |
sense_dimmed_sleep/s41598023340024.txt | Skip to main content
Thank you for visiting nature.com. You are using a browser version with
limited support for CSS. To obtain the best experience, we recommend you use a
more up to date browser (or turn off compatibility mode in Internet Explorer).
In the meantime, to ensure continued support, we are displaying the site
without styles and JavaScript.
Advertisement
[
](//pubads.g.doubleclick.net/gampad/jump?iu=/285/scientific_reports/article&sz=728x90&c=-2025072510&t=pos%3Dtop%26type%3Darticle%26artid%3Ds41598-023-34002-4%26doi%3D10.1038/s41598-023-34002-4%26subjmeta%3D1785,476,692,699%26kwrd%3DDiseases,Psychiatric+disorders,Respiratory+tract+diseases)
[  ](/srep)
* [ View all journals ](https://www.nature.com/siteindex)
* Search
* [ Log in ](https://idp.nature.com/auth/personal/springernature?redirect_uri=https://www.nature.com/articles/s41598-023-34002-4)
* Explore content
* About the journal
* Publish with us
* [ Sign up for alerts ](https://idp.nature.com/auth/personal/springernature?redirect_uri=https%3A%2F%2Fwww.nature.com%2Fmy-account%2Falerts%2Fsubscribe-journal%3Flist-id%3D288%26journal-link%3Dhttps%253A%252F%252Fwww.nature.com%252Fsrep%252F)
* [ RSS feed ](https://www.nature.com/srep.rss)
1. [ nature ](/)
2. [ scientific reports ](/srep)
3. [ articles ](/srep/articles?type=article)
4. article
Respiratory arousal threshold among patients with isolated sleep apnea and
with comorbid insomnia (COMISA)
[ Download PDF ](/articles/s41598-023-34002-4.pdf)
[ Download PDF ](/articles/s41598-023-34002-4.pdf)
* Article
* [ Open access ](https://www.springernature.com/gp/open-research/about/the-fundamentals-of-open-access-and-open-research)
* Published: 11 May 2023
# Respiratory arousal threshold among patients with isolated sleep apnea and
with comorbid insomnia (COMISA)
* Marcela Yanagimori 1 ,
* Mariana D. Fernandes 1 ,
* Michelle L. Garcia 1 ,
* Paula G. Scudeller 1 ,
* Carlos R. R. Carvalho 1 ,
* Bradley Edwards 2 ,
* Geraldo Lorenzi-Filho 1 &
* …
* Pedro R. Genta 1
Show authors
[ _Scientific Reports_ ](/srep) ** volume 13 ** , Article number: 7638 (
2023 ) Cite this article
* 1639 Accesses
* 2 Citations
* 10 Altmetric
* [ Metrics details ](/articles/s41598-023-34002-4/metrics)
### Subjects
* [ Diseases ](/subjects/diseases)
* [ Psychiatric disorders ](/subjects/psychiatric-disorders)
* [ Respiratory tract diseases ](/subjects/respiratory-tract-diseases)
## Abstract
Insomnia and obstructive sleep apnea (OSA) are common sleep disorders and
frequently coexist (COMISA). Arousals from sleep may be a common link
explaining the frequent comorbidity of both disorders. Respiratory arousal
threshold (AT) is a physiologic measurement of the level of respiratory effort
to trigger an arousal from sleep. The impact of COMISA on AT is not known. We
hypothesized that a low AT is more common among COMISA than among patients
with OSA without insomnia. Participants referred for OSA diagnosis underwent a
type 3 sleep study and answered the insomnia severity index (ISI)
questionnaire and the Epworth sleepiness scale. Participants with an ISI score
≥ 15 were defined as having insomnia. Sleep apnea was defined as an apnea
hypopnea index (AHI) ≥ 15 events/h. Low AT was determined using a previously
validated score based on 3 polysomnography variables (AHI, nadir SpO 2 and
the frequency of hypopneas). OSA-only (n = 51) and COMISA (n = 52)
participants had similar age (61[52–68] vs 60[53–65] years), body-mass index
(31.3[27.7–36.2] vs 32.2[29.5–38.3] kg/m 2 ) and OSA severity (40.2[27.5–60]
vs 37.55[27.9–65.2] events/h): all _p_ = NS. OSA-only group had significantly
more males than the COMISA group (58% vs 33%, _p_ = 0.013. The proportion of
participants with a low AT among OSA-only and COMISA groups was similar (29 vs
33%, _p_ = NS). The similar proportion of low AT among COMISA and patients
with OSA suggests that the respiratory arousal threshold may not be related to
the increased arousability of insomnia.
### Similar content being viewed by others
### [ Association between excessive daytime sleepiness, REM phenotype and
severity of obstructive sleep apnea
](https://www.nature.com/articles/s41598-019-56478-9?fromPaywallRec=false)
Article Open access 08 January 2020
### [ Prevalence and characteristics of pain in moderate-to-severe
obstructive sleep apnea patients and effect of CPAP treatment
](https://www.nature.com/articles/s41598-023-42967-5?fromPaywallRec=false)
Article Open access 21 September 2023
### [ A novel parameter is better than the AHI to assess nocturnal hypoxaemia
and excessive daytime sleepiness in obstructive sleep apnoea
](https://www.nature.com/articles/s41598-021-84239-0?fromPaywallRec=false)
Article Open access 25 February 2021
## Introduction
Obstructive sleep apnea and insomnia are highly prevalent sleep disorders that
are associated with impaired daytime functioning and reduced quality of life
[ 1 ](/articles/s41598-023-34002-4#ref-CR1 "Chung, K. F. Insomnia subtypes and
their relationships to daytime sleepiness in patients with obstructive sleep
apnea. Respiration 72\(5\), 460–465.
https://doi.org/10.1159/000087668
\(2005\).") . The comorbidity of insomnia and sleep apnea (COMISA) is associated to poorer health outcomes [ 2 ](/articles/s41598-023-34002-4#ref-CR2 "Sweetman, A., Lack, L. & Bastien, C. Co-morbid insomnia and sleep apnea \(COMISA\): Prevalence, consequences, methodological considerations, and recent randomized controlled trials. Brain Sci. 9\(12\), 1–18.
https://doi.org/10.3390/brainsci9120371
\(2019\).") . Arousals from sleep are common in both insomnia and OSA and may be a common link explaining the frequent comorbidity of both disorders.
The respiratory arousal threshold (AT) is defined as the level of ventilatory
drive that triggers an arousal from sleep at the termination of a respiratory
event [ 3 ](/articles/s41598-023-34002-4#ref-CR3 "Edwards, B. A. et al.
Clinical predictors of the respiratory arousal threshold in patients with
obstructive sleep apnea. Am. J. Respir. Crit. Care Med. 190\(11\), 1293–1300.
https://doi.org/10.1164/rccm.201404-0718OC
\(2014\).") . A low AT has been implicated in the pathogenesis of OSA and may affect one-third of moderate to severe OSA patients [ 4 ](/articles/s41598-023-34002-4#ref-CR4 "El-Solh, A. A., Lawson, Y. & Wilding, G. E. Impact of low arousal threshold on treatment of obstructive sleep apnea in patients with post-traumatic stress disorder. Sleep Breath. 25\(2\), 597–604.
https://doi.org/10.1007/s11325-020-02106-0
\(2021\).") . Patients with a low AT typically have respiratory events that terminate early, preventing the opportunity for ventilatory drive to build up and restore pharyngeal patency during sleep and promoting sleep fragmentation. Arousability may describe a particular phenotypical trait of insomnia patients [ 5 ](/articles/s41598-023-34002-4#ref-CR5 "Coren, S. Prediction of insomnia from arousability predisposition scores: Scale development and cross-validation. Behav. Res. Ther. 26\(5\), 415–420.
https://doi.org/10.1016/0005-7967\(88\)90076-9
\(1988\).") . Arousability in these patients can be defined as the physiological, cognitive, emotional, and behavioral responsiveness of individuals to particular variations in environmental stressful conditions [ 6 ](/articles/s41598-023-34002-4#ref-CR6 "Puzino, K. et al. Arousability as a trait predisposition to insomnia: Multidimensional structure and clinical utility of the Spanish and English versions of the arousal predisposition scale. Sleep Med. 81, 235–243.
https://doi.org/10.1016/j.sleep.2021.02.033
\(2021\).") and is associated with insomnia severity as measured by the Insomnia Severity Index (ISI) [ 6 ](/articles/s41598-023-34002-4#ref-CR6 "Puzino, K. et al. Arousability as a trait predisposition to insomnia: Multidimensional structure and clinical utility of the Spanish and English versions of the arousal predisposition scale. Sleep Med. 81, 235–243.
https://doi.org/10.1016/j.sleep.2021.02.033
\(2021\).") .
Insomnia subtypes are associated with co-existing disorders such as
depression, anxiety and sleep apnea [ 7 ](/articles/s41598-023-34002-4#ref-
CR7 "Hong, B. K. et al. DSM-IV psychiatric comorbidity according to symptoms
of insomnia: A nationwide sample of Korean adults. Soc. Psychiatry Psychiatr.
Epidemiol. 47\(12\), 2019–2033.
https://doi.org/10.1007/s00127-012-0502-0
\(2012\).") . Middle insomnia is the most prevalent subtype in COMISA subjects, possibly due to frequent arousals at the end of respiratory events [ 1 ](/articles/s41598-023-34002-4#ref-CR1 "Chung, K. F. Insomnia subtypes and their relationships to daytime sleepiness in patients with obstructive sleep apnea. Respiration 72\(5\), 460–465.
https://doi.org/10.1159/000087668
\(2005\).") , [ 8 ](/articles/s41598-023-34002-4#ref-CR8 "Björnsdóttir, E. et al. Symptoms of insomnia among patients with obstructive sleep apnea before and after two years of positive airway pressure treatment. Sleep 36\(12\), 1901–1909.
https://doi.org/10.5665/sleep.3226
\(2013\).") . The arousal threshold has not been studied according to the different insomnia subtypes.
Understanding the relationship between respiratory AT and arousability can
shed light to the understanding of the pathophysiology implicated in COMISA
and allow targeting more specific treatments. For instance, hypnotics are
commonly used to treat insomnia [ 9 ](/articles/s41598-023-34002-4#ref-CR9
"Sateia, M., Buysse, D., Krystal, A. D., Neubauer, D. & Heald, J. Clinical
practice guideline for the pharmacologic treatment of chronic insomnia in
adults. J. Clin. Sleep. Med. 13\(5\), 307–349.
https://doi.org/10.5664/jcsm.6470
\(2017\).") . Hypnotics aiming to increase the arousal threshold have also been tried as a treatment for OSA, resulting in OSA improvement for some individuals 10 , 11 , [ 12 ](/articles/s41598-023-34002-4#ref-CR12 "Sweetman, A. et al. Bi-directional relationships between co-morbid insomnia and sleep apnea \(COMISA\). Sleep Med. Rev. 60, 101519.
https://doi.org/10.1016/j.smrv.2021.101519
\(2021\).") . The purpose of the present study is to assess the AT among participants with COMISA and those with OSA only. We hypothesized that a low AT is more common among COMISA than among OSA patients without insomnia.
## Participants and methods
### Participants
Participants included in this study participated in a larger prospective study
between September 2019 and February 2020 that addressed clinical
characteristics of OSA among patients undergoing a sleep study for suspected
OSA. After written informed consent was obtained, all participants answered
standardized questionnaires about insomnia and daytime sleepiness. Demographic
and anthropometric data included age, gender, BMI, neck circumference,
comorbidities and sleep questionnaires.
### Questionnaires
Insomnia was characterized using the Insomnia Severity Index (ISI)
questionnaire. The ISI questionnaire assesses symptoms and severity of
insomnia using 7 standardized questions. Participants with an ISI score ≥ 15
were defined as having insomnia [ 13 ](/articles/s41598-023-34002-4#ref-CR13
"Clemente, V. et al. The European Portuguese version of the insomnia severity
index. J. Sleep Res. 30\(1\), e13198.
https://doi.org/10.1111/jsr.13198
\(2021\).") . Initial, middle and late insomnia subtypes were characterized using the answers of the three ISI questions assessing difficulty falling or staying asleep and waking up too early. In these 3 questions, participants checked one of the five responses (none, mild, moderate, severe and very severe). Severe and very severe answers were used to define insomnia subtypes. ISI nocturnal sub-score was calculated by the sum of first three items from the ISI questionnaire.
Daytime sleepiness was evaluated with the Epworth Sleepiness Scale (ESS). The
ESS assesses the likelihood of falling asleep during eight common daily
situations, with higher scores indicating greater sleepiness. An ESS ≥ 11 was
used to define excessive daytime sleepiness [ 14
](/articles/s41598-023-34002-4#ref-CR14 "Johns, M. W. A new method for
measuring daytime sleepiness: The Epworth sleepiness scale. Sleep 14\(6\),
540–545.
https://doi.org/10.1093/sleep/14.6.540
\(1991\).") .
### Sleep studies
Sleep studies were performed at home using a type 3 monitor (Apnealink Plus,
Resmed, San Diego, CA). This device has an oximeter, a thoracoabdominal effort
belt and nasal cannula. All studies were reviewed by a single investigator,
according to the American Academy of Sleep Medicine (AASM) Manual for Scoring
Sleep and Associated events. The minimum duration of respiratory events was 10
s(s). Apneas were defined as a cessation of airflow for 10 s. Hypopneas were
defined as a reduction of the airflow signal amplitude ≥ 30%, associated with
a 3% oxygen desaturation. The AHI was calculated as the number of apneas and
hypopneas divided by the recording duration in hours. OSA was defined as an
AHI ≥ 15 events/h.
### Arousal threshold
Low AT was determined using a previously validated score based on 3
polysomnography variables that considers one point for each of the following 3
criteria: AHI < 30 events/h, a nadir SpO 2 > 82.5%, and the proportion of
hypopneas/sum of apneas and hypopneas > 58.3% [ 3
](/articles/s41598-023-34002-4#ref-CR3 "Edwards, B. A. et al. Clinical
predictors of the respiratory arousal threshold in patients with obstructive
sleep apnea. Am. J. Respir. Crit. Care Med. 190\(11\), 1293–1300.
https://doi.org/10.1164/rccm.201404-0718OC
\(2014\).") . Patients were classified as having low AT based if the score was ≥ 2.
### Eligible group
From the database of 998 patients, 920 answered the ISI questionnaire. Using
insomnia (ISI ≥ 15) and OSA (AHI ≥ 15 events/h) criteria, participants were
classified into four groups: (1) none (231 participants); (2) OSA-only (261
participants); (3) insomnia only (199 participants) and; (4) COMISA (OSA and
insomnia) (229 participants). Since we did not have a preliminary study to
base the expected difference in arousal threshold, we studied a random sample
of 103 participants out of the entire group of 490 participants with COMISA
and OSA-only.
### Statistical analysis
The normality of the distribution of continuous variables was assessed with
the Kolmogorov–Smirnov test. Continuous variables were described as mean ±
standard deviation or median [25th–75th percentiles]. Categorical variables
were presented as whole numbers and percentages. Differences between variables
were compared using the chi-square test, Student´s unpaired t- or Mann–Whitney
tests. Analyses were performed with IBM SPSS Statistics 20 (Chicago, USA).
All methods were carried out in accordance with relevant guidelines and
regulations and all protocols were approved by Comissão de Ética e Pesquisa
(CEP) from FMUSP.
## Results
Fifty-one participants from the OSA-only group and 52 participants from the
COMISA group were randomly selected from the larger database of 490
participants. Anthropometric and clinical characteristics of the study
population (n = 103) are shown in Table [ 1
](/articles/s41598-023-34002-4#Tab1) and did not differ from the larger
database (data not shown). Patients with OSA-only were predominantly male,
while those with COMISA were predominantly female. OSA severity was similar
between groups. The proportion of participants with a low AT was similar
between OSA-only and COMISA groups. As expected, ISI was lower among OSA-only
as compared to COMISA participants. Sensitivity analysis considering each
gender separately did not affect the results observed when the whole group of
participants were analyzed (data not shown).
**Table 1 Anthropometric and clinical characteristics of study population.**
[ Full size table ](/articles/s41598-023-34002-4/tables/1)
Characteristics of low AT and high AT groups are shown in Table [ 2
](/articles/s41598-023-34002-4#Tab2) . Compared with the high AT group,
patients with low AT were composed of a higher percentage of women, were less
obese and had lower AHI.
**Table 2 Clinical characteristics of participants with Low and High AT.**
[ Full size table ](/articles/s41598-023-34002-4/tables/2)
In patients with COMISA, ISI scores were similar among participants with a low
AT 19[18–22] (n = 35) and participants with a high AT 18[16–21] (n = 17) ( _p_
= 0.34). Initial, middle and late insomnia was observed among 38.5, 65.4,
32.7% of COMISA participants. The proportion of low and high AT was similar
among each insomnia subtype (initial, middle and terminal). ISI nocturnal sub-
score was also similar between low and high AT (Table [ 3
](/articles/s41598-023-34002-4#Tab3) ). The presence of comorbidities was
similar between groups, except for depression, which was more prevalent among
COMISA participants ( _p_ = 0.04).
**Table 3 Clinical characteristics of participants with COMISA according to a
Low and High AT.**
[ Full size table ](/articles/s41598-023-34002-4/tables/3)
## Discussion
The major finding of our study was that insomnia did not impact arousal
threshold among OSA patients as COMISA patients and OSA-only patients had a
similar proportion of low AT. Insomnia severity was also similar among COMISA
patients with or without a low AT. These findings suggest that the mechanisms
leading to respiratory arousals are different than spontaneous arousals
experienced by insomnia patients.
Arousal threshold can be defined as the magnitude of ventilatory drive in
response to a respiratory stimulus terminating with an arousal [ 15
](/articles/s41598-023-34002-4#ref-CR15 "Gleeson, K., Zwillich, C. W. & White,
D. P. The influence of increasing ventilatory effort on arousal from sleep.
Am. Rev. Respir. Dis. 142\(2\), 295–300.
https://doi.org/10.1164/ajrccm/142.2.295
\(1990\).") . The concept of AT was defined by the observation that negative inspiratory pleural pressure during the breaths preceding arousal were similar, whether stimulated by added inspiratory resistive load, hypoxia, or hypercapnia [ 15 ](/articles/s41598-023-34002-4#ref-CR15 "Gleeson, K., Zwillich, C. W. & White, D. P. The influence of increasing ventilatory effort on arousal from sleep. Am. Rev. Respir. Dis. 142\(2\), 295–300.
https://doi.org/10.1164/ajrccm/142.2.295
\(1990\).") . This finding supported the hypothesis that arousal from sleep resulting from the stimulation of ventilation is due to the increase in ventilatory drive. Participants with a low AT have been referred as “light sleepers” or “easily arousable”, suggesting that AT would be a marker of arousability regardless of respiratory effort [ 12 ](/articles/s41598-023-34002-4#ref-CR12 "Sweetman, A. et al. Bi-directional relationships between co-morbid insomnia and sleep apnea \(COMISA\). Sleep Med. Rev. 60, 101519.
https://doi.org/10.1016/j.smrv.2021.101519
\(2021\).") , [ 16 ](/articles/s41598-023-34002-4#ref-CR16 "Gray, E. L., McKenzie, D. K. & Eckert, D. J. Obstructive sleep apnea without obesity is common and difficult to treat: Evidence for a distinct pathophysiological phenotype. J. Clin. Sleep Med. 13\(1\), 81–88.
https://doi.org/10.5664/jcsm.6394
\(2017\).") , [ 17 ](/articles/s41598-023-34002-4#ref-CR17 "Zinchuk, A. et al. Prevalence, associated clinical features, and impact on continuous positive airway pressure use of a low respiratory arousal threshold among male United States veterans with obstructive sleep apnea. J. Clin. Sleep Med. 14\(5\), 809–817.
https://doi.org/10.5664/jcsm.7112
\(2018\).") . Conditioned arousals to airway occlusion have been suggested as an alternative mechanism leading to arousals in insomnia patients and may be associated with higher arousability [ 12 ](/articles/s41598-023-34002-4#ref-CR12 "Sweetman, A. et al. Bi-directional relationships between co-morbid insomnia and sleep apnea \(COMISA\). Sleep Med. Rev. 60, 101519.
https://doi.org/10.1016/j.smrv.2021.101519
\(2021\).") . In the present study, the proportion of participants with a low AT was similar among OSA patients with and without comorbid insomnia. In addition, insomnia severity was also similar among participants with a low and high AT. A previous study addressed AT among OSA patients with insomnia and post-traumatic stress disorder (PTSD) [ 4 ](/articles/s41598-023-34002-4#ref-CR4 "El-Solh, A. A., Lawson, Y. & Wilding, G. E. Impact of low arousal threshold on treatment of obstructive sleep apnea in patients with post-traumatic stress disorder. Sleep Breath. 25\(2\), 597–604.
https://doi.org/10.1007/s11325-020-02106-0
\(2021\).") . Although insomnia was associated with low AT, only male OSA veterans with PTSD were studied [ 4 ](/articles/s41598-023-34002-4#ref-CR4 "El-Solh, A. A., Lawson, Y. & Wilding, G. E. Impact of low arousal threshold on treatment of obstructive sleep apnea in patients with post-traumatic stress disorder. Sleep Breath. 25\(2\), 597–604.
https://doi.org/10.1007/s11325-020-02106-0
\(2021\).") .Two recent abstracts addressed the arousal threshold in COMISA subjects in smaller populations. In one study, no relationship between ISI and AT in the whole group that included OSA-only and COMISA subjects (n = 46) was observed [ 18 ](/articles/s41598-023-34002-4#ref-CR18 "Zheng, J. et al. The insomnia severity index is related to the respiratory arousal threshold in people with co-morbid insomnia and sleep apnoea \(COMISA\). Sleep Adv. 3, A57–A58.
https://doi.org/10.1093/sleepadvances/zpac029.156
\(2022\).") . However, an inverse association between ISI and AT in the subgroup of COMISA subjects (n = 27) was reported [ 18 ](/articles/s41598-023-34002-4#ref-CR18 "Zheng, J. et al. The insomnia severity index is related to the respiratory arousal threshold in people with co-morbid insomnia and sleep apnoea \(COMISA\). Sleep Adv. 3, A57–A58.
https://doi.org/10.1093/sleepadvances/zpac029.156
\(2022\).") . OSA severity and AT among OSA and COMISA groups were not reported or compared [ 18 ](/articles/s41598-023-34002-4#ref-CR18 "Zheng, J. et al. The insomnia severity index is related to the respiratory arousal threshold in people with co-morbid insomnia and sleep apnoea \(COMISA\). Sleep Adv. 3, A57–A58.
https://doi.org/10.1093/sleepadvances/zpac029.156
\(2022\).") . In another abstract, AT was lower among COMISA subjects [ 19 ](/articles/s41598-023-34002-4#ref-CR19 "Brooker, E. et al. Obstructive sleep apnea is a distinct physiological phenotype in individuals with comorbid insomnia and sleep apnea\(COMISA\). Sleep Adv. 3\(1\), A22.
https://doi.org/10.1093/sleepadvances/zpac029.052
\(2022\).") . However, COMISA subjects tended to have milder OSA, which may bias AT comparison since patients with a low AT tend to have milder OSA severity [ 17 ](/articles/s41598-023-34002-4#ref-CR17 "Zinchuk, A. et al. Prevalence, associated clinical features, and impact on continuous positive airway pressure use of a low respiratory arousal threshold among male United States veterans with obstructive sleep apnea. J. Clin. Sleep Med. 14\(5\), 809–817.
https://doi.org/10.5664/jcsm.7112
\(2018\).") . Some studies have shown that a low AT is associated with poor CPAP adherence [ 16 ](/articles/s41598-023-34002-4#ref-CR16 "Gray, E. L., McKenzie, D. K. & Eckert, D. J. Obstructive sleep apnea without obesity is common and difficult to treat: Evidence for a distinct pathophysiological phenotype. J. Clin. Sleep Med. 13\(1\), 81–88.
https://doi.org/10.5664/jcsm.6394
\(2017\).") , [ 17 ](/articles/s41598-023-34002-4#ref-CR17 "Zinchuk, A. et al. Prevalence, associated clinical features, and impact on continuous positive airway pressure use of a low respiratory arousal threshold among male United States veterans with obstructive sleep apnea. J. Clin. Sleep Med. 14\(5\), 809–817.
https://doi.org/10.5664/jcsm.7112
\(2018\).") , [ 20 ](/articles/s41598-023-34002-4#ref-CR20 "Zinchuk, A. V. et al. Physiological traits and adherence to obstructive sleep apnea treatment in patients with stroke. Am. J. Respir. Crit. Care Med. 201\(12\), 1568–1572.
https://doi.org/10.1164/rccm.201911-2203LE
\(2020\).") , [ 21 ](/articles/s41598-023-34002-4#ref-CR21 "Wu, H., Fang, F., Wu, C., Zhan, X. & Wei, Y. Low arousal threshold is associated with unfavorable shift of PAP compliance over time in patients with OSA. Sleep Breath. 25\(2\), 887–895.
https://doi.org/10.1007/s11325-0-20-02197-9
\(2020\).") .. However, this association may also be biased by lower OSA severity, which has been shown to be a strong predictor of CPAP adherence [ 22 ](/articles/s41598-023-34002-4#ref-CR22 "Kohler, M., Smith, D., Tippett, V. & Stradling, J. R. Predictors of long-term compliance with continuous positive airway pressure. Thorax 65\(9\), 829–832.
https://doi.org/10.1136/thx.2010.135848
\(2010\).") , [ 23 ](/articles/s41598-023-34002-4#ref-CR23 "Krieger, J., Kurtz, D., Petiau, C., Sforza, E. & Trautmann, D. Long-term compliance with CPAP therapy in obstructive sleep apnea patients and in snorers. Sleep 19\(9 SUPPL.\), 136–143.
https://doi.org/10.1093/sleep/19.suppl_9.s136
\(1996\).") . For instance, the difference in AHI among participants with a low and high AT in a previous study (17 and 48 events/h, respectively) [ 17 ](/articles/s41598-023-34002-4#ref-CR17 "Zinchuk, A. et al. Prevalence, associated clinical features, and impact on continuous positive airway pressure use of a low respiratory arousal threshold among male United States veterans with obstructive sleep apnea. J. Clin. Sleep Med. 14\(5\), 809–817.
https://doi.org/10.5664/jcsm.7112
\(2018\).") is similar to the findings of the present study (23 and 53 events/h, low and high AT respectively). Therefore, milder OSA severity may bias the comparison of AT and CPAP adherence between OSA-only and COMISA subjects.
Middle insomnia is the most common insomnia subtype among COMISA participants
[ 1 ](/articles/s41598-023-34002-4#ref-CR1 "Chung, K. F. Insomnia subtypes and
their relationships to daytime sleepiness in patients with obstructive sleep
apnea. Respiration 72\(5\), 460–465.
https://doi.org/10.1159/000087668
\(2005\).") , [ 8 ](/articles/s41598-023-34002-4#ref-CR8 "Björnsdóttir, E. et al. Symptoms of insomnia among patients with obstructive sleep apnea before and after two years of positive airway pressure treatment. Sleep 36\(12\), 1901–1909.
https://doi.org/10.5665/sleep.3226
\(2013\).") . In the present study, middle insomnia was also the most common insomnia subtype. Although insomnia subtype comparison was underpowered, participants with isolated middle insomnia had a similar proportion of low AT as compared to other insomnia subtypes. Arousability is a trait of insomnia that can be defined as the physiological, cognitive, emotional, and behavioral responsiveness of individuals to particular variations in environmental conditions, particularly stressful ones [ 6 ](/articles/s41598-023-34002-4#ref-CR6 "Puzino, K. et al. Arousability as a trait predisposition to insomnia: Multidimensional structure and clinical utility of the Spanish and English versions of the arousal predisposition scale. Sleep Med. 81, 235–243.
https://doi.org/10.1016/j.sleep.2021.02.033
\(2021\).") . Arousability can be determined using self-reported instruments [ 24 ](/articles/s41598-023-34002-4#ref-CR24 "Coren, S. & Mah, K. B. Prediction of physiological arousability: A validation of the Arousal Predisposition Scale. Behav. Res. Ther. 31\(2\), 215–219.
https://doi.org/10.1016/0005-7967\(93\)90076-7
\(1993\).") and has been associated with insomnia severity as measured by the ISI [ 6 ](/articles/s41598-023-34002-4#ref-CR6 "Puzino, K. et al. Arousability as a trait predisposition to insomnia: Multidimensional structure and clinical utility of the Spanish and English versions of the arousal predisposition scale. Sleep Med. 81, 235–243.
https://doi.org/10.1016/j.sleep.2021.02.033
\(2021\).") , [ 25 ](/articles/s41598-023-34002-4#ref-CR25 "Marques, D. R., Gomes, A. A., Helena, M. & De, A. P. Portuguese version of the arousal predisposition scale: Preliminary evidence for a two-factor structure in a nonclinical sample. Psychol. Rep. 121\(5\), 974–991.
https://doi.org/10.1177/0033294117742654
\(2018\).") . The similar proportion of low AT between COMISA and OSA-only participants and among isolated middle and other insomnia subtypes suggest that the higher arousability found among insomnia participants is a different phenomenon than the ventilatoty effort-related arousal threshold.
Our findings agree with previous studies that compared clinical
characteristics of low and high arousal threshold groups. In the present
study, low AT patients had a lower BMI, were predominantly female and had a
lower AHI [ 17 ](/articles/s41598-023-34002-4#ref-CR17 "Zinchuk, A. et al.
Prevalence, associated clinical features, and impact on continuous positive
airway pressure use of a low respiratory arousal threshold among male United
States veterans with obstructive sleep apnea. J. Clin. Sleep Med. 14\(5\),
809–817.
https://doi.org/10.5664/jcsm.7112
\(2018\).") , [ 26 ](/articles/s41598-023-34002-4#ref-CR26 "Hang, L., Huang, C. & Cheng, W. Clinical characteristics of Asian patients with sleep Apnea with low arousal threshold and sleep structure change with continuous positive airway pressure. Sleep Breath. 25\(3\), 1309–1317.
https://doi.org/10.1007/s11325-020-02235-6
\(2020\).") , [ 27 ](/articles/s41598-023-34002-4#ref-CR27 "Young, T., Peppard, P. E. & Taheri, S. Excess weight and sleep-disordered breathing. J. Appl. Physiol. 99\(4\), 1592–1599.
https://doi.org/10.1152/japplphysiol.00587.2005
\(2005\).") . Another study showed that normal body weight was a poor predictor of CPAP adherence among participants with a low AT [ 16 ](/articles/s41598-023-34002-4#ref-CR16 "Gray, E. L., McKenzie, D. K. & Eckert, D. J. Obstructive sleep apnea without obesity is common and difficult to treat: Evidence for a distinct pathophysiological phenotype. J. Clin. Sleep Med. 13\(1\), 81–88.
https://doi.org/10.5664/jcsm.6394
\(2017\).") . Nevertheless, the major predictor of CPAP use was the interaction between obesity and low AT, not any of these variables alone [ 16 ](/articles/s41598-023-34002-4#ref-CR16 "Gray, E. L., McKenzie, D. K. & Eckert, D. J. Obstructive sleep apnea without obesity is common and difficult to treat: Evidence for a distinct pathophysiological phenotype. J. Clin. Sleep Med. 13\(1\), 81–88.
https://doi.org/10.5664/jcsm.6394
\(2017\).") . Participants with OSA may increase their AT during the course of the disease, tolerating increasingly longer obstructive events as the disease evolves. After a period of CPAP treatment, AT tends to decrease [ 28 ](/articles/s41598-023-34002-4#ref-CR28 "Haba-rubio, J. & Sforza, E. Effect of CPAP treatment on inspiratory arousal threshold during NREM sleep in OSAS. Sleep Breath. 9\(1\), 12–19.
https://doi.org/10.1007/s11325-005-0002-5
\(2005\).") , reinforcing the concept that a higher AT may be a consequence of OSA severity.
We should point recognizable limitations of the present study. First, low AT
determination was based on an algorithm and not based on the invasive
quantitative assessment conducted in specialized physiologic laboratory.
Second, the algorithm used for calculating the arousal threshold has been
validated for OSA patients, but not specifically for COMISA subjects. However,
this approach allowed us to analyze a reasonable number of subjects. Third, we
used a type 3 monitor, which may underestimate OSA severity and impact the
classification of AT. Nevertheless, the type of sleep monitor used would
affect both groups equally and would unlikely affect the final results.
Fourth, the sample size was not determined a priori due to the lack of
previous studies to derive information. Fifth we used ISI to define insomnia,
instead of the diagnostic and statistical manual of mental disorders criteria
(DSM). However, ISI has a high accuracy to detect insomnia and has the
advantage of being able to determine insomnia severity [ 29
](/articles/s41598-023-34002-4#ref-CR29 "Seng, L. et al. Identifying the best
sleep measure to screen clinical insomnia in a psychiatric population. Sleep
Med. 41, 8693.
https://doi.org/10.1016/j.sleep.2017.09.015
\(2017\).") . Finally, one night of monitoring can lead to misclassification of disease severity in patients with mild and moderate OSA [ 30 ](/articles/s41598-023-34002-4#ref-CR30 "Punjabi, N. M. et al. Variability and missclassificationof sleep apnea severity based on multi-night testing. Chest 158\(1\), 365–373.
https://doi.org/10.1016/j.chest.2020.01.039
\(2017\).") , [ 31 ](/articles/s41598-023-34002-4#ref-CR31 "Lechat, B. et al. Multinight prevalence, variability, and diagnostic missclassification of obstructive sleep apnea. Am. J. Respir. Crit. Care Med. 205\(5\), 563–569.
https://doi.org/10.1164/rccm.202107-1761OC
\(2022\).") . However, most included subjects had severe OSA.
In summary, a similar proportion of low AT among OSA-only and COMISA patients.
Our findings suggest that a low AT is not a characteristic of COMISA patients.
## Data availability
The datasets generated during and/or analyzed during the current study are
available from the corresponding author on reasonable request.
## References
1. Chung, K. F. Insomnia subtypes and their relationships to daytime sleepiness in patients with obstructive sleep apnea. _Respiration_ **72** (5), 460–465. [ https://doi.org/10.1159/000087668 ](https://doi.org/10.1159/000087668) (2005).
[ Article ](https://doi.org/10.1159%2F000087668) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=16210883)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Insomnia%20subtypes%20and%20their%20relationships%20to%20daytime%20sleepiness%20in%20patients%20with%20obstructive%20sleep%20apnea&journal=Respiration&doi=10.1159%2F000087668&volume=72&issue=5&pages=460-465&publication_year=2005&author=Chung%2CKF)
2. Sweetman, A., Lack, L. & Bastien, C. Co-morbid insomnia and sleep apnea (COMISA): Prevalence, consequences, methodological considerations, and recent randomized controlled trials. _Brain Sci._ **9** (12), 1–18. [ https://doi.org/10.3390/brainsci9120371 ](https://doi.org/10.3390/brainsci9120371) (2019).
[ Article ](https://doi.org/10.3390%2Fbrainsci9120371) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Co-
morbid%20insomnia%20and%20sleep%20apnea%20%28COMISA%29%3A%20Prevalence%2C%20consequences%2C%20methodological%20considerations%2C%20and%20recent%20randomized%20controlled%20trials&journal=Brain%20Sci.&doi=10.3390%2Fbrainsci9120371&volume=9&issue=12&pages=1-18&publication_year=2019&author=Sweetman%2CA&author=Lack%2CL&author=Bastien%2CC)
3. Edwards, B. A. _et al._ Clinical predictors of the respiratory arousal threshold in patients with obstructive sleep apnea. _Am. J. Respir. Crit. Care Med._ **190** (11), 1293–1300. [ https://doi.org/10.1164/rccm.201404-0718OC ](https://doi.org/10.1164/rccm.201404-0718OC) (2014).
[ Article ](https://doi.org/10.1164%2Frccm.201404-0718OC) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25321848)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4315811) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Clinical%20predictors%20of%20the%20respiratory%20arousal%20threshold%20in%20patients%20with%20obstructive%20sleep%20apnea&journal=Am.%20J.%20Respir.%20Crit.%20Care%20Med.&doi=10.1164%2Frccm.201404-0718OC&volume=190&issue=11&pages=1293-1300&publication_year=2014&author=Edwards%2CBA&author=Eckert%2CDJ&author=McSharry%2CDG)
4. El-Solh, A. A., Lawson, Y. & Wilding, G. E. Impact of low arousal threshold on treatment of obstructive sleep apnea in patients with post-traumatic stress disorder. _Sleep Breath._ **25** (2), 597–604. [ https://doi.org/10.1007/s11325-020-02106-0 ](https://doi.org/10.1007/s11325-020-02106-0) (2021).
[ Article ](https://link.springer.com/doi/10.1007/s11325-020-02106-0) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32458377)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Impact%20of%20low%20arousal%20threshold%20on%20treatment%20of%20obstructive%20sleep%20apnea%20in%20patients%20with%20post-
traumatic%20stress%20disorder&journal=Sleep%20Breath.&doi=10.1007%2Fs11325-020-02106-0&volume=25&issue=2&pages=597-604&publication_year=2021&author=El-
Solh%2CAA&author=Lawson%2CY&author=Wilding%2CGE)
5. Coren, S. Prediction of insomnia from arousability predisposition scores: Scale development and cross-validation. _Behav. Res. Ther._ **26** (5), 415–420. [ https://doi.org/10.1016/0005-7967(88)90076-9 ](https://doi.org/10.1016/0005-7967\(88\)90076-9) (1988).
[ Article ](https://doi.org/10.1016%2F0005-7967%2888%2990076-9) [ ADS
](http://adsabs.harvard.edu/cgi-bin/nph-
data_query?link_type=ABSTRACT&bibcode=1988teuh.book.....C) [ CAS
](/articles/cas-redirect/1:STN:280:DyaL1M%2FltVSnsg%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=3190651)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Prediction%20of%20insomnia%20from%20arousability%20predisposition%20scores%3A%20Scale%20development%20and%20cross-
validation&journal=Behav.%20Res.%20Ther.&doi=10.1016%2F0005-7967%2888%2990076-9&volume=26&issue=5&pages=415-420&publication_year=1988&author=Coren%2CS)
6. Puzino, K. _et al._ Arousability as a trait predisposition to insomnia: Multidimensional structure and clinical utility of the Spanish and English versions of the arousal predisposition scale. _Sleep Med._ **81** , 235–243. [ https://doi.org/10.1016/j.sleep.2021.02.033 ](https://doi.org/10.1016/j.sleep.2021.02.033) (2021).
[ Article ](https://doi.org/10.1016%2Fj.sleep.2021.02.033) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=33721601)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Arousability%20as%20a%20trait%20predisposition%20to%20insomnia%3A%20Multidimensional%20structure%20and%20clinical%20utility%20of%20the%20Spanish%20and%20English%20versions%20of%20the%20arousal%20predisposition%20scale&journal=Sleep%20Med.&doi=10.1016%2Fj.sleep.2021.02.033&volume=81&pages=235-243&publication_year=2021&author=Puzino%2CK&author=Frye%2CSS&author=Lagrotte%2CC&author=Vgontzas%2CAN&author=Calhoun%2CSL&author=Fernandez-
mendoza%2CJ)
7. Hong, B. K. _et al._ DSM-IV psychiatric comorbidity according to symptoms of insomnia: A nationwide sample of Korean adults. _Soc. Psychiatry Psychiatr. Epidemiol._ **47** (12), 2019–2033. [ https://doi.org/10.1007/s00127-012-0502-0 ](https://doi.org/10.1007/s00127-012-0502-0) (2012).
[ Article ](https://link.springer.com/doi/10.1007/s00127-012-0502-0) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=22526822)
[ Google Scholar ](http://scholar.google.com/scholar_lookup?&title=DSM-
IV%20psychiatric%20comorbidity%20according%20to%20symptoms%20of%20insomnia%3A%20A%20nationwide%20sample%20of%20Korean%20adults&journal=Soc.%20Psychiatry%20Psychiatr.%20Epidemiol.&doi=10.1007%2Fs00127-012-0502-0&volume=47&issue=12&pages=2019-2033&publication_year=2012&author=Hong%2CBK&author=Jeon%2CJ&author=Pyo%2CJ)
8. Björnsdóttir, E. _et al._ Symptoms of insomnia among patients with obstructive sleep apnea before and after two years of positive airway pressure treatment. _Sleep_ **36** (12), 1901–1909. [ https://doi.org/10.5665/sleep.3226 ](https://doi.org/10.5665/sleep.3226) (2013).
[ Article ](https://doi.org/10.5665%2Fsleep.3226) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=24293765)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3825440) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Symptoms%20of%20insomnia%20among%20patients%20with%20obstructive%20sleep%20apnea%20before%20and%20after%20two%20years%20of%20positive%20airway%20pressure%20treatment&journal=Sleep&doi=10.5665%2Fsleep.3226&volume=36&issue=12&pages=1901-1909&publication_year=2013&author=Bj%C3%B6rnsd%C3%B3ttir%2CE&author=Janson%2CC&author=Sigurdsson%2CJF)
9. Sateia, M., Buysse, D., Krystal, A. D., Neubauer, D. & Heald, J. Clinical practice guideline for the pharmacologic treatment of chronic insomnia in adults. _J. Clin. Sleep. Med._ **13** (5), 307–349. [ https://doi.org/10.5664/jcsm.6470 ](https://doi.org/10.5664/jcsm.6470) (2017).
[ Article ](https://doi.org/10.5664%2Fjcsm.6470) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27998379)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5263087) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Clinical%20practice%20guideline%20for%20the%20pharmacologic%20treatment%20of%20chronic%20insomnia%20in%20adults&journal=J.%20Clin.%20Sleep.%20Med.&doi=10.5664%2Fjcsm.6470&volume=13&issue=5&pages=307-349&publication_year=2017&author=Sateia%2CM&author=Buysse%2CD&author=Krystal%2CAD&author=Neubauer%2CD&author=Heald%2CJ)
10. Messineo, L. _et al._ Zolpidem increases sleep efficiency and the respiratory arousal threshold without changing sleep apnoea severity and pharyngeal muscle activity. _J. Physiol._ **598** (20), 4681–4692. [ https://doi.org/10.1113/JP280173 ](https://doi.org/10.1113/JP280173) (2020).
[ Article ](https://doi.org/10.1113%2FJP280173) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BB3cXhs12jtb%2FE) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32864734)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Zolpidem%20increases%20sleep%20efficiency%20and%20the%20respiratory%20arousal%20threshold%20without%20changing%20sleep%20apnoea%20severity%20and%20pharyngeal%20muscle%20activity&journal=J.%20Physiol.&doi=10.1113%2FJP280173&volume=598&issue=20&pages=4681-4692&publication_year=2020&author=Messineo%2CL&author=Eckert%2CDJ&author=Carter%2CSG)
11. Eckert, D. J., Malhotra, A., Wellman, A. & White, D. P. Trazodone increases the respiratory arousal threshold in patients with obstructive sleep apnea and a low arousal threshold. _Sleep_ **37** (4), 811–819. [ https://doi.org/10.5665/sleep.3596 ](https://doi.org/10.5665/sleep.3596) (2014).
[ Article ](https://doi.org/10.5665%2Fsleep.3596) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=24899767)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4044741) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Trazodone%20increases%20the%20respiratory%20arousal%20threshold%20in%20patients%20with%20obstructive%20sleep%20apnea%20and%20a%20low%20arousal%20threshold&journal=Sleep&doi=10.5665%2Fsleep.3596&volume=37&issue=4&pages=811-819&publication_year=2014&author=Eckert%2CDJ&author=Malhotra%2CA&author=Wellman%2CA&author=White%2CDP)
12. Sweetman, A. _et al._ Bi-directional relationships between co-morbid insomnia and sleep apnea (COMISA). _Sleep Med. Rev._ **60** , 101519. [ https://doi.org/10.1016/j.smrv.2021.101519 ](https://doi.org/10.1016/j.smrv.2021.101519) (2021).
[ Article ](https://doi.org/10.1016%2Fj.smrv.2021.101519) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=34229295)
[ Google Scholar ](http://scholar.google.com/scholar_lookup?&title=Bi-
directional%20relationships%20between%20co-
morbid%20insomnia%20and%20sleep%20apnea%20%28COMISA%29&journal=Sleep%20Med.%20Rev.&doi=10.1016%2Fj.smrv.2021.101519&volume=60&publication_year=2021&author=Sweetman%2CA&author=Lack%2CL&author=Mcevoy%2CRD)
13. Clemente, V. _et al._ The European Portuguese version of the insomnia severity index. _J. Sleep Res._ **30** (1), e13198. [ https://doi.org/10.1111/jsr.13198 ](https://doi.org/10.1111/jsr.13198) (2021).
[ Article ](https://doi.org/10.1111%2Fjsr.13198) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32997368)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20European%20Portuguese%20version%20of%20the%20insomnia%20severity%20index&journal=J.%20Sleep%20Res.&doi=10.1111%2Fjsr.13198&volume=30&issue=1&publication_year=2021&author=Clemente%2CV&author=Marques%2CDR&author=Miller-
mendes%2CM&author=Morin%2CC&author=Serra%2CJ&author=Allen%2CA)
14. Johns, M. W. A new method for measuring daytime sleepiness: The Epworth sleepiness scale. _Sleep_ **14** (6), 540–545. [ https://doi.org/10.1093/sleep/14.6.540 ](https://doi.org/10.1093/sleep/14.6.540) (1991).
[ Article ](https://doi.org/10.1093%2Fsleep%2F14.6.540) [ CAS ](/articles/cas-
redirect/1:STN:280:DyaK387ovVSksw%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=1798888)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=A%20new%20method%20for%20measuring%20daytime%20sleepiness%3A%20The%20Epworth%20sleepiness%20scale&journal=Sleep&doi=10.1093%2Fsleep%2F14.6.540&volume=14&issue=6&pages=540-545&publication_year=1991&author=Johns%2CMW)
15. Gleeson, K., Zwillich, C. W. & White, D. P. The influence of increasing ventilatory effort on arousal from sleep. _Am. Rev. Respir. Dis._ **142** (2), 295–300. [ https://doi.org/10.1164/ajrccm/142.2.295 ](https://doi.org/10.1164/ajrccm/142.2.295) (1990).
[ Article ](https://doi.org/10.1164%2Fajrccm%2F142.2.295) [ CAS
](/articles/cas-redirect/1:STN:280:DyaK3czktlWgtg%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=2382892)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20influence%20of%20increasing%20ventilatory%20effort%20on%20arousal%20from%20sleep&journal=Am.%20Rev.%20Respir.%20Dis.&doi=10.1164%2Fajrccm%2F142.2.295&volume=142&issue=2&pages=295-300&publication_year=1990&author=Gleeson%2CK&author=Zwillich%2CCW&author=White%2CDP)
16. Gray, E. L., McKenzie, D. K. & Eckert, D. J. Obstructive sleep apnea without obesity is common and difficult to treat: Evidence for a distinct pathophysiological phenotype. _J. Clin. Sleep Med._ **13** (1), 81–88. [ https://doi.org/10.5664/jcsm.6394 ](https://doi.org/10.5664/jcsm.6394) (2017).
[ Article ](https://doi.org/10.5664%2Fjcsm.6394) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27655455)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5181619) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Obstructive%20sleep%20apnea%20without%20obesity%20is%20common%20and%20difficult%20to%20treat%3A%20Evidence%20for%20a%20distinct%20pathophysiological%20phenotype&journal=J.%20Clin.%20Sleep%20Med.&doi=10.5664%2Fjcsm.6394&volume=13&issue=1&pages=81-88&publication_year=2017&author=Gray%2CEL&author=McKenzie%2CDK&author=Eckert%2CDJ)
17. Zinchuk, A. _et al._ Prevalence, associated clinical features, and impact on continuous positive airway pressure use of a low respiratory arousal threshold among male United States veterans with obstructive sleep apnea. _J. Clin. Sleep Med._ **14** (5), 809–817. [ https://doi.org/10.5664/jcsm.7112 ](https://doi.org/10.5664/jcsm.7112) (2018).
[ Article ](https://doi.org/10.5664%2Fjcsm.7112) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=29734986)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5940432) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Prevalence%2C%20associated%20clinical%20features%2C%20and%20impact%20on%20continuous%20positive%20airway%20pressure%20use%20of%20a%20low%20respiratory%20arousal%20threshold%20among%20male%20United%20States%20veterans%20with%20obstructive%20sleep%20apnea&journal=J.%20Clin.%20Sleep%20Med.&doi=10.5664%2Fjcsm.7112&volume=14&issue=5&pages=809-817&publication_year=2018&author=Zinchuk%2CA&author=Edwards%2CBA&author=Jeon%2CS)
18. Zheng, J. _et al._ The insomnia severity index is related to the respiratory arousal threshold in people with co-morbid insomnia and sleep apnoea (COMISA). _Sleep Adv._ **3** , A57–A58. [ https://doi.org/10.1093/sleepadvances/zpac029.156 ](https://doi.org/10.1093/sleepadvances/zpac029.156) (2022).
[ Article ](https://doi.org/10.1093%2Fsleepadvances%2Fzpac029.156) [ Google
Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20insomnia%20severity%20index%20is%20related%20to%20the%20respiratory%20arousal%20threshold%20in%20people%20with%20co-
morbid%20insomnia%20and%20sleep%20apnoea%20%28COMISA%29&journal=Sleep%20Adv.&doi=10.1093%2Fsleepadvances%2Fzpac029.156&volume=3&pages=A57-A58&publication_year=2022&author=Zheng%2CJ&author=Tong%2CB&author=Sweetman%2CA)
19. Brooker, E. _et al._ Obstructive sleep apnea is a distinct physiological phenotype in individuals with comorbid insomnia and sleep apnea(COMISA). _Sleep Adv._ **3** (1), A22. [ https://doi.org/10.1093/sleepadvances/zpac029.052 ](https://doi.org/10.1093/sleepadvances/zpac029.052) (2022).
[ Article ](https://doi.org/10.1093%2Fsleepadvances%2Fzpac029.052) [ Google
Scholar
](http://scholar.google.com/scholar_lookup?&title=Obstructive%20sleep%20apnea%20is%20a%20distinct%20physiological%20phenotype%20in%20individuals%20with%20comorbid%20insomnia%20and%20sleep%20apnea%28COMISA%29&journal=Sleep%20Adv.&doi=10.1093%2Fsleepadvances%2Fzpac029.052&volume=3&issue=1&publication_year=2022&author=Brooker%2CE&author=Thomson%2CL&author=Landry%2CS)
20. Zinchuk, A. V. _et al._ Physiological traits and adherence to obstructive sleep apnea treatment in patients with stroke. _Am. J. Respir. Crit. Care Med._ **201** (12), 1568–1572. [ https://doi.org/10.1164/rccm.201911-2203LE ](https://doi.org/10.1164/rccm.201911-2203LE) (2020).
[ Article ](https://doi.org/10.1164%2Frccm.201911-2203LE) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32083949)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7301748) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Physiological%20traits%20and%20adherence%20to%20obstructive%20sleep%20apnea%20treatment%20in%20patients%20with%20stroke&journal=Am.%20J.%20Respir.%20Crit.%20Care%20Med.&doi=10.1164%2Frccm.201911-2203LE&volume=201&issue=12&pages=1568-1572&publication_year=2020&author=Zinchuk%2CAV&author=Redeker%2CNS&author=Chu%2CJH)
21. Wu, H., Fang, F., Wu, C., Zhan, X. & Wei, Y. Low arousal threshold is associated with unfavorable shift of PAP compliance over time in patients with OSA. _Sleep Breath._ **25** (2), 887–895. [ https://doi.org/10.1007/s11325-0-20-02197-9 ](https://doi.org/10.1007/s11325-0-20-02197-9) (2020).
[ Article ](https://link.springer.com/doi/10.1007/s11325-0-20-02197-9) [
PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=33011910)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Low%20arousal%20threshold%20is%20associated%20with%20unfavorable%20shift%20of%20PAP%20compliance%20over%20time%20in%20patients%20with%20OSA&journal=Sleep%20Breath.&doi=10.1007%2Fs11325-0-20-02197-9&volume=25&issue=2&pages=887-895&publication_year=2020&author=Wu%2CH&author=Fang%2CF&author=Wu%2CC&author=Zhan%2CX&author=Wei%2CY)
22. Kohler, M., Smith, D., Tippett, V. & Stradling, J. R. Predictors of long-term compliance with continuous positive airway pressure. _Thorax_ **65** (9), 829–832. [ https://doi.org/10.1136/thx.2010.135848 ](https://doi.org/10.1136/thx.2010.135848) (2010).
[ Article ](https://doi.org/10.1136%2Fthx.2010.135848) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=20805182)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Predictors%20of%20long-
term%20compliance%20with%20continuous%20positive%20airway%20pressure&journal=Thorax&doi=10.1136%2Fthx.2010.135848&volume=65&issue=9&pages=829-832&publication_year=2010&author=Kohler%2CM&author=Smith%2CD&author=Tippett%2CV&author=Stradling%2CJR)
23. Krieger, J., Kurtz, D., Petiau, C., Sforza, E. & Trautmann, D. Long-term compliance with CPAP therapy in obstructive sleep apnea patients and in snorers. _Sleep_ **19** (9 SUPPL.), 136–143. [ https://doi.org/10.1093/sleep/19.suppl_9.s136 ](https://doi.org/10.1093/sleep/19.suppl_9.s136) (1996).
[ Article ](https://doi.org/10.1093%2Fsleep%2F19.suppl_9.s136) [ Google
Scholar ](http://scholar.google.com/scholar_lookup?&title=Long-
term%20compliance%20with%20CPAP%20therapy%20in%20obstructive%20sleep%20apnea%20patients%20and%20in%20snorers&journal=Sleep&doi=10.1093%2Fsleep%2F19.suppl_9.s136&volume=19&issue=9%20SUPPL.&pages=136-143&publication_year=1996&author=Krieger%2CJ&author=Kurtz%2CD&author=Petiau%2CC&author=Sforza%2CE&author=Trautmann%2CD)
24. Coren, S. & Mah, K. B. Prediction of physiological arousability: A validation of the Arousal Predisposition Scale. _Behav. Res. Ther._ **31** (2), 215–219. [ https://doi.org/10.1016/0005-7967(93)90076-7 ](https://doi.org/10.1016/0005-7967\(93\)90076-7) (1993).
[ Article ](https://doi.org/10.1016%2F0005-7967%2893%2990076-7) [ CAS
](/articles/cas-redirect/1:STN:280:DyaK3s7otlWnug%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=8442749)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Prediction%20of%20physiological%20arousability%3A%20A%20validation%20of%20the%20Arousal%20Predisposition%20Scale&journal=Behav.%20Res.%20Ther.&doi=10.1016%2F0005-7967%2893%2990076-7&volume=31&issue=2&pages=215-219&publication_year=1993&author=Coren%2CS&author=Mah%2CKB)
25. Marques, D. R., Gomes, A. A., Helena, M. & De, A. P. Portuguese version of the arousal predisposition scale: Preliminary evidence for a two-factor structure in a nonclinical sample. _Psychol. Rep._ **121** (5), 974–991. [ https://doi.org/10.1177/0033294117742654 ](https://doi.org/10.1177/0033294117742654) (2018).
[ Article ](https://doi.org/10.1177%2F0033294117742654) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Portuguese%20version%20of%20the%20arousal%20predisposition%20scale%3A%20Preliminary%20evidence%20for%20a%20two-
factor%20structure%20in%20a%20nonclinical%20sample&journal=Psychol.%20Rep.&doi=10.1177%2F0033294117742654&volume=121&issue=5&pages=974-991&publication_year=2018&author=Marques%2CDR&author=Gomes%2CAA&author=Helena%2CM&author=De%2CAP)
26. Hang, L., Huang, C. & Cheng, W. Clinical characteristics of Asian patients with sleep Apnea with low arousal threshold and sleep structure change with continuous positive airway pressure. _Sleep Breath._ **25** (3), 1309–1317. [ https://doi.org/10.1007/s11325-020-02235-6 ](https://doi.org/10.1007/s11325-020-02235-6) (2020).
[ Article ](https://link.springer.com/doi/10.1007/s11325-020-02235-6) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=33123927)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Clinical%20characteristics%20of%20Asian%20patients%20with%20sleep%20Apnea%20with%20low%20arousal%20threshold%20and%20sleep%20structure%20change%20with%20continuous%20positive%20airway%20pressure&journal=Sleep%20Breath.&doi=10.1007%2Fs11325-020-02235-6&volume=25&issue=3&pages=1309-1317&publication_year=2020&author=Hang%2CL&author=Huang%2CC&author=Cheng%2CW)
27. Young, T., Peppard, P. E. & Taheri, S. Excess weight and sleep-disordered breathing. _J. Appl. Physiol._ **99** (4), 1592–1599. [ https://doi.org/10.1152/japplphysiol.00587.2005 ](https://doi.org/10.1152/japplphysiol.00587.2005) (2005).
[ Article ](https://doi.org/10.1152%2Fjapplphysiol.00587.2005) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=16160020)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Excess%20weight%20and%20sleep-
disordered%20breathing&journal=J.%20Appl.%20Physiol.&doi=10.1152%2Fjapplphysiol.00587.2005&volume=99&issue=4&pages=1592-1599&publication_year=2005&author=Young%2CT&author=Peppard%2CPE&author=Taheri%2CS)
28. Haba-rubio, J. & Sforza, E. Effect of CPAP treatment on inspiratory arousal threshold during NREM sleep in OSAS. _Sleep Breath._ **9** (1), 12–19. [ https://doi.org/10.1007/s11325-005-0002-5 ](https://doi.org/10.1007/s11325-005-0002-5) (2005).
[ Article ](https://link.springer.com/doi/10.1007/s11325-005-0002-5) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=15785916)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Effect%20of%20CPAP%20treatment%20on%20inspiratory%20arousal%20threshold%20during%20NREM%20sleep%20in%20OSAS&journal=Sleep%20Breath.&doi=10.1007%2Fs11325-005-0002-5&volume=9&issue=1&pages=12-19&publication_year=2005&author=Haba-
rubio%2CJ&author=Sforza%2CE)
29. Seng, L. _et al._ Identifying the best sleep measure to screen clinical insomnia in a psychiatric population. _Sleep Med._ **41** , 8693. [ https://doi.org/10.1016/j.sleep.2017.09.015 ](https://doi.org/10.1016/j.sleep.2017.09.015) (2017).
[ Article ](https://doi.org/10.1016%2Fj.sleep.2017.09.015) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Identifying%20the%20best%20sleep%20measure%20to%20screen%20clinical%20insomnia%20in%20a%20psychiatric%20population&journal=Sleep%20Med.&doi=10.1016%2Fj.sleep.2017.09.015&volume=41&publication_year=2017&author=Seng%2CL&author=Seow%2CE&author=Abdin%2CE)
30. Punjabi, N. M. _et al._ Variability and missclassificationof sleep apnea severity based on multi-night testing. _Chest_ **158** (1), 365–373. [ https://doi.org/10.1016/j.chest.2020.01.039 ](https://doi.org/10.1016/j.chest.2020.01.039) (2017).
[ Article ](https://doi.org/10.1016%2Fj.chest.2020.01.039) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Variability%20and%20missclassificationof%20sleep%20apnea%20severity%20based%20on%20multi-
night%20testing&journal=Chest&doi=10.1016%2Fj.chest.2020.01.039&volume=158&issue=1&pages=365-373&publication_year=2017&author=Punjabi%2CNM&author=Patil%2CS&author=Crainiceanu%2CC)
31. Lechat, B. _et al._ Multinight prevalence, variability, and diagnostic missclassification of obstructive sleep apnea. _Am. J. Respir. Crit. Care Med._ **205** (5), 563–569. [ https://doi.org/10.1164/rccm.202107-1761OC ](https://doi.org/10.1164/rccm.202107-1761OC) (2022).
[ Article ](https://doi.org/10.1164%2Frccm.202107-1761OC) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=34904935)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Multinight%20prevalence%2C%20variability%2C%20and%20diagnostic%20missclassification%20of%20obstructive%20sleep%20apnea&journal=Am.%20J.%20Respir.%20Crit.%20Care%20Med.&doi=10.1164%2Frccm.202107-1761OC&volume=205&issue=5&pages=563-569&publication_year=2022&author=Lechat%2CB&author=Naik%2CG&author=Reynolds%2CA)
[ Download references ](https://citation-
needed.springer.com/v2/references/10.1038/s41598-023-34002-4?format=refman&flavour=references)
## Funding
This study was funded by Conselho Nacional de Desenvolvimento Científico e
Tecnológico under grand number 313348/2017-0, and Fundação de Amparo à
Pesquisa do Estado de São Paulo under grand number 2018/201612-4.
## Author information
### Authors and Affiliations
1. Laboratorio do Sono, LIM 63, Divisao de Pneumologia, Instituto do Coracao (InCor), Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
Marcela Yanagimori, Mariana D. Fernandes, Michelle L. Garcia, Paula G.
Scudeller, Carlos R. R. Carvalho, Geraldo Lorenzi-Filho & Pedro R. Genta
2. Sleep and Circadian Medicine Laboratory, Department of Physiology and School of Psychological Sciences, Faculty of Medicine, Nursing and Health Sciences, Monash University, Melbourne, VIC, Australia
Bradley Edwards
Authors
1. Marcela Yanagimori
[ View author publications ](/search?author=Marcela%20Yanagimori)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Marcela%20Yanagimori)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Marcela%20Yanagimori%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
2. Mariana D. Fernandes
[ View author publications ](/search?author=Mariana%20D.%20Fernandes)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Mariana%20D.%20Fernandes)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Mariana%20D.%20Fernandes%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
3. Michelle L. Garcia
[ View author publications ](/search?author=Michelle%20L.%20Garcia)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Michelle%20L.%20Garcia)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Michelle%20L.%20Garcia%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
4. Paula G. Scudeller
[ View author publications ](/search?author=Paula%20G.%20Scudeller)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Paula%20G.%20Scudeller)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Paula%20G.%20Scudeller%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
5. Carlos R. R. Carvalho
[ View author publications ](/search?author=Carlos%20R.%20R.%20Carvalho)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Carlos%20R.%20R.%20Carvalho)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Carlos%20R.%20R.%20Carvalho%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
6. Bradley Edwards
[ View author publications ](/search?author=Bradley%20Edwards)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Bradley%20Edwards)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Bradley%20Edwards%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
7. Geraldo Lorenzi-Filho
[ View author publications ](/search?author=Geraldo%20Lorenzi-Filho)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Geraldo%20Lorenzi-
Filho) [ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Geraldo%20Lorenzi-
Filho%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
8. Pedro R. Genta
[ View author publications ](/search?author=Pedro%20R.%20Genta)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Pedro%20R.%20Genta)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Pedro%20R.%20Genta%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
### Contributions
Conceptualization: P.R.G, G.L.F; Methodology: P.R.G, G.L.F, M.Y; Formal
analysis and investigation: P.R.G, M.Y, G.L.F, M.D.F, M.L.G, P.G.S, C.R.C,
B.E; Writing—original draft preparation: P.R.G, G.L.F, M.Y; Writing—review and
editing P.R.G, M.Y, G.L.F, B.E; Final Approval P.R.G, M.Y, G.L.F, M.D.F,
M.L.G, P.G.S, C.R.C, B.E; Supervision: P.R.G, G.L.F, B.E, C.R.C. The
manuscript has been read and approved by all named authors.
### Corresponding author
Correspondence to [ Marcela Yanagimori ](mailto:[email protected]) .
## Ethics declarations
### Competing interests
The authors declare no competing interests.
## Additional information
### Publisher's note
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
## Rights and permissions
**Open Access** This article is licensed under a Creative Commons Attribution
4.0 International License, which permits use, sharing, adaptation,
distribution and reproduction in any medium or format, as long as you give
appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons licence, and indicate if changes were made. The images or
other third party material in this article are included in the article's
Creative Commons licence, unless indicated otherwise in a credit line to the
material. If material is not included in the article's Creative Commons
licence and your intended use is not permitted by statutory regulation or
exceeds the permitted use, you will need to obtain permission directly from
the copyright holder. To view a copy of this licence, visit [
http://creativecommons.org/licenses/by/4.0/
](http://creativecommons.org/licenses/by/4.0/) .
[ Reprints and permissions
](https://s100.copyright.com/AppDispatchServlet?title=Respiratory%20arousal%20threshold%20among%20patients%20with%20isolated%20sleep%20apnea%20and%20with%20comorbid%20insomnia%20%28COMISA%29&author=Marcela%20Yanagimori%20et%20al&contentID=10.1038%2Fs41598-023-34002-4©right=The%20Author%28s%29&publication=2045-2322&publicationDate=2023-05-11&publisherName=SpringerNature&orderBeanReset=true&oa=CC%20BY)
## About this article
[ 
](https://crossmark.crossref.org/dialog/?doi=10.1038/s41598-023-34002-4)
### Cite this article
Yanagimori, M., Fernandes, M.D., Garcia, M.L. _et al._ Respiratory arousal
threshold among patients with isolated sleep apnea and with comorbid insomnia
(COMISA). _Sci Rep_ **13** , 7638 (2023).
https://doi.org/10.1038/s41598-023-34002-4
[ Download citation ](https://citation-
needed.springer.com/v2/references/10.1038/s41598-023-34002-4?format=refman&flavour=citation)
* Received : 26 October 2022
* Accepted : 22 April 2023
* Published : 11 May 2023
* DOI : https://doi.org/10.1038/s41598-023-34002-4
### Share this article
Anyone you share the following link with will be able to read this content:
Get shareable link
Sorry, a shareable link is not currently available for this article.
Copy to clipboard
Provided by the Springer Nature SharedIt content-sharing initiative
## Comments
By submitting a comment you agree to abide by our [ Terms ](/info/tandc.html)
and [ Community Guidelines ](/info/community-guidelines.html) . If you find
something abusive or that does not comply with our terms or guidelines please
flag it as inappropriate.
[ Download PDF ](/articles/s41598-023-34002-4.pdf)
Advertisement
[
](//pubads.g.doubleclick.net/gampad/jump?iu=/285/scientific_reports/article&sz=300x250&c=723329383&t=pos%3Dright%26type%3Darticle%26artid%3Ds41598-023-34002-4%26doi%3D10.1038/s41598-023-34002-4%26subjmeta%3D1785,476,692,699%26kwrd%3DDiseases,Psychiatric+disorders,Respiratory+tract+diseases)
## Explore content
* [ Research articles ](/srep/research-articles)
* [ News & Comment ](/srep/news-and-comment)
* [ Collections ](/srep/collections)
* [ Subjects ](/srep/browse-subjects)
* [ Follow us on Facebook ](https://www.facebook.com/scientificreports)
* [ Follow us on Twitter ](https://twitter.com/SciReports)
* [ Sign up for alerts ](https://www.nature.com/my-account/alerts/subscribe-journal?list-id=288)
* [ RSS feed ](https://www.nature.com/srep.rss)
## About the journal
* [ Open Access Fees and Funding ](/srep/open-access)
* [ About Scientific Reports ](/srep/about)
* [ Contact ](/srep/contact)
* [ Journal policies ](/srep/journal-policies)
* [ Calls for Papers ](/srep/calls-for-papers)
* [ Guide to referees ](/srep/guide-to-referees)
* [ Editor's Choice ](/srep/editorschoice)
* [ Journal highlights ](/srep/highlights)
## Publish with us
* [ For authors ](/srep/author-instructions)
* [ Language editing services ](https://authorservices.springernature.com/go/sn/?utm_source=For+Authors&utm_medium=Website_Nature&utm_campaign=Platform+Experimentation+2022&utm_id=PE2022)
* [ Submit manuscript ](https://author-welcome.nature.com/41598)
## Search
Search articles by subject, keyword or author
Show results from All journals This journal
Search
[ Advanced search ](/search/advanced)
### Quick links
* [ Explore articles by subject ](/subjects)
* [ Find a job ](/naturecareers)
* [ Guide to authors ](/authors/index.html)
* [ Editorial policies ](/authors/editorial_policies/)
Scientific Reports ( _Sci Rep_ ) ISSN 2045-2322 (online)
## nature.com sitemap
### About Nature Portfolio
* [ About us ](https://www.nature.com/npg_/company_info/index.html)
* [ Press releases ](https://www.nature.com/npg_/press_room/press_releases.html)
* [ Press office ](https://press.nature.com/)
* [ Contact us ](https://support.nature.com/support/home)
### Discover content
* [ Journals A-Z ](https://www.nature.com/siteindex)
* [ Articles by subject ](https://www.nature.com/subjects)
* [ protocols.io ](https://www.protocols.io/)
* [ Nature Index ](https://www.natureindex.com/)
### Publishing policies
* [ Nature portfolio policies ](https://www.nature.com/authors/editorial_policies)
* [ Open access ](https://www.nature.com/nature-research/open-access)
### Author & Researcher services
* [ Reprints & permissions ](https://www.nature.com/reprints)
* [ Research data ](https://www.springernature.com/gp/authors/research-data)
* [ Language editing ](https://authorservices.springernature.com/language-editing/)
* [ Scientific editing ](https://authorservices.springernature.com/scientific-editing/)
* [ Nature Masterclasses ](https://masterclasses.nature.com/)
* [ Research Solutions ](https://solutions.springernature.com/)
### Libraries & institutions
* [ Librarian service & tools ](https://www.springernature.com/gp/librarians/tools-services)
* [ Librarian portal ](https://www.springernature.com/gp/librarians/manage-your-account/librarianportal)
* [ Open research ](https://www.nature.com/openresearch/about-open-access/information-for-institutions)
* [ Recommend to library ](https://www.springernature.com/gp/librarians/recommend-to-your-library)
### Advertising & partnerships
* [ Advertising ](https://partnerships.nature.com/product/digital-advertising/)
* [ Partnerships & Services ](https://partnerships.nature.com/)
* [ Media kits ](https://partnerships.nature.com/media-kits/)
* [ Branded content ](https://partnerships.nature.com/product/branded-content-native-advertising/)
### Professional development
* [ Nature Careers ](https://www.nature.com/naturecareers/)
* [ Nature Conferences ](https://conferences.nature.com)
### Regional websites
* [ Nature Africa ](https://www.nature.com/natafrica)
* [ Nature China ](http://www.naturechina.com)
* [ Nature India ](https://www.nature.com/nindia)
* [ Nature Italy ](https://www.nature.com/natitaly)
* [ Nature Japan ](https://www.natureasia.com/ja-jp)
* [ Nature Middle East ](https://www.nature.com/nmiddleeast)
* [ Privacy Policy ](https://www.nature.com/info/privacy)
* [ Use of cookies ](https://www.nature.com/info/cookies)
* Your privacy choices/Manage cookies
* [ Legal notice ](https://www.nature.com/info/legal-notice)
* [ Accessibility statement ](https://www.nature.com/info/accessibility-statement)
* [ Terms & Conditions ](https://www.nature.com/info/terms-and-conditions)
* [ Your US state privacy rights ](https://www.springernature.com/ccpa)
[ 
](https://www.springernature.com/)
© 2024 Springer Nature Limited
Close banner Close
Sign up for the _Nature Briefing_ newsletter — what matters in science, free
to your inbox daily.
Email address
Sign up
I agree my information will be processed in accordance with the _Nature_ and
Springer Nature Limited [ Privacy Policy
](https://www.nature.com/info/privacy) .
Close banner Close
Get the most important science stories of the day, free in your inbox. [ Sign
up for Nature Briefing
](https://www.nature.com/briefing/signup/?brieferEntryPoint=MainBriefingBanner)
*[
DOI
]: Digital Object Identifier
*[
ISSN
]: International Standard Serial Number
| biology | 1755407 | https://no.wikipedia.org/wiki/Petter%20Bae%20Brandtz%C3%A6g | Petter Bae Brandtzæg | Petter Bae Brandtzæg (født 31. oktober 1969 i Oslo) er en norsk medieforsker som er professor ved Universitetet i Oslo.
Brandtzæg har hovedfag i psykologi fra NTNU, og en PhD i medier og kommunikasjon fra Universitetet i Oslo. Spesialområdet er internett og sosiale medier, og han har forsket på hvordan vår nye digitale hverdag påvirker sosiale relasjoner og samfunnsengasjement. Han har særlig markert seg i den offentlig debatten om hvilke konsekvenser sosiale medier har på individer og samfunnet. I 2008 bidro Brandtzæg sammen med flere til at Redd Barna endret sine nettvettregler i 2009.
Brandtzæg var i 2011 medlem i det offentlige utvalget "Ungdommens maktutredning", ledet av Trond Viggo Torgersen. Han var også medlem i utvalget for nasjonale retningslinjer for åpen tilgang til forskningsresultater, som leverte sin innstilling til Kunnskapsdepartementet 1. juni 2016. Brandtzæg er i perioden 1. januar 2017 til 31. desember 2024 varamedlem i den regjeringsoppnevnte Personvernsnemda ledet av Mari Bø Haugstad.
Han har publisert en rekke artikler og er redaksjonsmedlem i Nytt Norsk Tidsskrift. og i det internasjonale tidsskriftet Journal of Computer-Mediated Communication, Oxford Academic. Brandtzæg er på Universitetet i Stanford sin liste over "World Ranking Of Scientists" (2%), der han blant åtte millioner forskere i verden er plukket ut til å være blant to prosenten som har publisert mest og blitt sitert flest ganger.
Petter Bae Brandtzæg er forskningsleder og professor ved institutt for medier og kommunikasjon, Universitetet i Oslo, og sjefforsker ved SINTEF Digital.
Publikasjoner i tidsskrifter
Brandtzaeg, P. B., Pultier, A., & Moen, G.M. (2019). Losing Control to Data-Hungry Apps – A Mixed-Methods Approach to Mobile App Privacy. Social Science Computer Review, 37 (4),. 466–488 https://journals.sagepub.com/doi/full/10.1177/0894439318777706
Brandtzaeg, P. B., & Chaparro Domínguez, M.Á. (online first, 2019). From Youthful Experimentation to Professional Identity: Understanding Identity Transitions in Social Media. Young – Nordic Journal of Youth Research. https://journals.sagepub.com/doi/10.1177/1103308819834386
Skjuve, M., Haugstveit, I.M., Følstad, A., & Brandtzaeg, P. B. (2019) Help, is my chatbot falling into the uncanny valley? An empirical study of user experience in human-chatbot interaction. Human Technology, 15(1), 30- 54
Brandtzaeg, P. B. & Følstad, A. (2018). Chatbots – changing user needs and motivations. ACM Interactions, 25(5), 38-43 https://interactions.acm.org/archive/view/september-october-2018/chatbots
Brandtzaeg, P. B., & Lüders, M. (2018). Time Collapse in Social media: Extending the Context Collapse. Social Media + Society. 1-10. https://journals.sagepub.com/doi/full/10.1177/2056305118763349
Brandtzaeg, P. B., Følstad, A. & Chaparro Domínguez, M.Á. (2018). How Journalists and Social Media Users Perceive Online Fact-Checking and Verification Services. Journalism Practice, 12(9), 1109-1129. https://www.tandfonline.com/doi/full/10.1080/17512786.2017.1363657
Brandtzaeg, P. B., & Chaparro Domínguez, M.Á. (2018). A Gap in Networked Publics? A Comparison of Younger and Older Journalists’ Newsgathering Practices on Social Media. Nordicom Review, 39(1), 95–109 https://www.nordicom.gu.se/sv/publikationer/nordicom-review/nordicom-review-39-1-2018/gap-networked-publics-comparison-younger-and
Brandtzaeg, P. B., & Følstad, A. (2017). Trust and distrust in online fact-checking services. Communications of the ACM, 60(9): 65-71 https://dl.acm.org/citation.cfm?id=3122803
Følstad, A., & Brandtzaeg, P.B. (2017). Chatbots and the new world of HCI. ACM Interactions, 24 (4), 38-42 https://interactions.acm.org/archive/view/july-august-2017/chatbots-and-the-new-world-of-hci
Lüders, M., & Brandtzaeg, P. B. (2017). ‘My children tell me it’s so simple’ – A mixed-methods approach to understand older non-users’ perceptions of social networking sites. New Media & Society, 19(2), 181-198. https://journals.sagepub.com/doi/abs/10.1177/1461444814554064
Brandtzaeg, P.B. (2017). Facebook is no «great equalizer»: A big data approach to gender differences in civic engagement across countries. Social Science Computer Review, 35(1), 103–125. https://journals.sagepub.com/doi/abs/10.1177/0894439315605806
Brandtzaeg, P. B., Haugestveit, I.M., Lüders, M., & Følstad, A. (2016). How Should Organizations Adapt to Youth Civic Engagement in Social Media? A Lead User Approach. Interacting with Computers, 28(5), 664-679. https://academic.oup.com/iwc/article-abstract/28/5/664/1750426?redirectedFrom=fulltext
Brandtzaeg, P. B., Lüders, M., Spangenberg, J., Rath-Wiggins, L., & Følstad, A. (2016). Emerging journalistic verification practices concerning social media. Journalism Practice, 10(3), 323-342. https://www.tandfonline.com/doi/abs/10.1080/17512786.2015.1020331
Mainsah, H., Brandtzaeg, P. B., & Følstad, A. (2016) Bridging the Generational Culture Gap in Youth Civic Engagement through Social Media: Lessons Learnt from Young Designers in Three Civic Organisations. The Journal of Media Innovations, 3(1), 23-40. https://journals.uio.no/index.php/TJMI/article/view/2724
Lüders, M., & Brandtzaeg, P. B. (2016). Når alt sosialt blir flyktig – En kvalitativ studie av hvordan eldre opplever sosiale medier. Norsk Medietidsskrift, 22(2), 2- 18.https://www.idunn.no/nmt/2016/02/naar_alt_sosialt_blir_flyktig_-_en_kvalitativ_studie_av_hvor
Brandtzaeg, P. B., & Haugstveit, I.M. (2014). Facebook Likes: A Study of Liking Practices for Humanitarian Causes. International Journal of Web Based Communities, 10(3), 258 – 279. https://www.inderscience.com/info/inarticle.php?artid=62942
Brandtzaeg, P. B. (2012). Social networking sites: their users and social implications – a longitudinal study. Journal of Computer-Mediated Communication, 17(4), 467-488. https://academic.oup.com/jcmc/article/17/4/467/4067681
Endestad, T., Heim, J. Kaare, B., Torgersen, L., & Brandtzaeg, P. B. (2011). Media User Types among Young Children and Social Displacement. Nordicom Review, 1(30), 17-30. https://www.nordicom.gu.se/sites/default/files/kapitel-pdf/337_endestad%20et%20al.pdf
Brandtzaeg, P.B., Heim, J., & Karahasanovic, A (2011). Understanding the new digital divide – A typology of Internet users in Europe. International Journal of Human Computer Studies, 69(3), 123-138. https://doi.org/10.1016/j.ijhcs.2010.11.004
Brandtzaeg, P.B., & Heim, J. (2011). A Typology of Social Networking Sites Users. International Journal of Web Based Communities, 7(1), 28-51. https://doi.org/10.1504/IJWBC.2011.038124
Brandtzaeg, P. B., Lüders, M., & Skjetne, J. H. (2010). Too many Facebook “friends”?Content sharing and sociability versus the need for privacy in social network sites. International Journal of Human-Computer Interaction, 26(11), 1006-1030. https://doi.org/10.1080/10447318.2010.516719
Brandtzaeg, P. B. (2010). Towards a unified Media-User Typology (MUT): A meta-analysis and review of the research literature on media-user typologies.Computers in Human Behavior, 26(5),940-956. https://www.sciencedirect.com/science/article/pii/S0747563210000245
Brandtzaeg, P. B., Heim, J., & Kaare, B. (2010). Bridging and Bonding in Social Network Sites – Investigating Family-Based Capital. International Journal of Web Based Communities, 6(3), 231-353.
Brandtzaeg, P. B., Staksrud, E., Hagen, I., & Wold, T. (2009). Norwegian children’s experiences of cyberbullying in different technological platforms. Journal of Children and Media, 3(4), 349-365. https://www.tandfonline.com/doi/full/10.1080/17482790903233366
Brandtzaeg, P. B., & Heim, J. (2009). Children’s Electronic Gaming Content Preferences and Psychosocial Factors – Is there a connection? Nordicom Review, 30(2), 69-87.
Karahasanović, A., Brandtzaeg, P.B., Vanattenhoven, J. Lievens, B., Nielsen, T. K., & Pierson, J. (2009). Ensuring Etiquette, Trust, and Privacy when developing Web 2.0 Applications. Computer, 42(6), 42-49. https://ieeexplore.ieee.org/document/5199592
Karahasanović, A., Brandtzaeg, P. B., Heim, J., Lüders, M., Vermeir, L., Pierson, J., Lievens, B., Vanattenhoven, J., & Jans, G. (2009). Co-Creation and User-Generated Content – Elderly People’s User Requirements. Computers in Human Behavior, 25(3), 655-679. https://doi.org/10.1016/j.chb.2008.08.012
Brandtzaeg, P. B., & Heim, J. (2008). ”Jeg liker ikke voldsspill” – En studie av norske barns spillinnholdspreferanser og psykososiale faktorer. Nordicom Information, 30(1), 77-85.
Heim, J., Brandtzaeg, P. B., Endestad, T., Kaare, B. H., & Torgersen, L. (2007). Children’s Usage of Media Technologies and Psychosocial Factors. New Media & Society, 9(3), 425-454.https://journals.sagepub.com/doi/abs/10.1177/1461444807076971
Kaare, B. H., Brandtzaeg, P. B., Endestad, T., & Heim, J. (2007). In the Borderland Between Family orientation and Peer-culture: The Use of Communication Technologies among Norwegian Tweens. New Media & Society, 9(4), 603-624. https://journals.sagepub.com/doi/10.1177/1461444807080328
Brandtzæg, P. B., & Stav, B. H. (2004). Barn og unges skravling på nettet – Sosial støtte i cyberspace? Tidsskrift for Ungdomsforskning, 4(1), 27-47. https://journals.hioa.no/index.php/ungdomsforskning/article/view/1139
Brandtzæg, P. B., Endestad, T., Heim, J., Kaare, B. H., & Torgersen, L. (2004). Barn i et digitalt samfunn. En beskrivelse av norske barn fra 7 til 12 år og deres tilgang til og bruk av TV, PC, Internett, mobiltelefon og spillteknologier. Barn, 22(4), 9-31. https://www.ntnu.no/documents/1272099285/1274624605/Brandtzaeg.pdf/475e8530-dd97-436a-b657-3c1b87358c0e
Bibliografi
Referanser
Norske medieforskere | norwegian_bokmål | 0.865074 |
sense_dimmed_sleep/s12931022021413.txt | Skip to main content
Advertisement
[
](//pubads.g.doubleclick.net/gampad/jump?iu=/270604982/bmc/respiratory-
research/articles&sz=728x90,970x90&pos=LB1&doi=10.1186/s12931-022-02141-3&type=article&kwrd=Positional
obstructive sleep apnea,Prevalence,Respiratory arousal threshold&pmc=H33134&)
[   ](https://www.biomedcentral.com)
Search
* [ Explore journals ](//www.biomedcentral.com/journals)
* [ Get published ](//www.biomedcentral.com/getpublished)
* [ About BMC ](//www.biomedcentral.com/about)
* [ My account ](https://www.biomedcentral.com/account)
Search all BMC articles
Search
[ Respiratory Research ](/)
* [ Home ](/)
* [ About ](/about)
* [ Articles ](/articles)
* [ Submission Guidelines ](/submission-guidelines)
* [ Submit manuscript ](https://submission.nature.com/new-submission/12931/3)
Prevalence, characteristics, and respiratory arousal threshold of positional
obstructive sleep apnea in China: a large scale study from Shanghai Sleep
Health Study cohort
[ Download PDF ](//respiratory-
research.biomedcentral.com/counter/pdf/10.1186/s12931-022-02141-3.pdf)
[ Download PDF ](//respiratory-
research.biomedcentral.com/counter/pdf/10.1186/s12931-022-02141-3.pdf)
* Research
* [ Open access ](https://www.springernature.com/gp/open-research/about/the-fundamentals-of-open-access-and-open-research)
* Published: 12 September 2022
# Prevalence, characteristics, and respiratory arousal threshold of
positional obstructive sleep apnea in China: a large scale study from Shanghai
Sleep Health Study cohort
* Weijun Huang 1 , 2 , 3 na1 ,
* Xiaoting Wang 1 , 2 , 3 na1 ,
* Chong Xu 1 , 2 , 3 ,
* Huajun Xu 1 , 2 , 3 ,
* Huaming Zhu 1 , 2 , 3 ,
* Suru Liu 1 , 2 , 3 ,
* Jianyin Zou 1 , 2 , 3 ,
* Jian Guan 1 , 2 , 3 ,
* Hongliang Yi 1 , 2 , 3 &
* …
* Shankai Yin 1 , 2 , 3
Show authors
[ _Respiratory Research_ ](/) ** volume 23 ** , Article number: 240 ( 2022
) Cite this article
* 2564 Accesses
* 11 Citations
* [ Metrics details ](/articles/10.1186/s12931-022-02141-3/metrics)
## Abstract
### Purpose
To evaluate the prevalence, characteristics, and respiratory arousal threshold
(ArTH) of Chinese patients with positional obstructive sleep apnea (POSA)
according to the Cartwright Classification (CC) and Amsterdam Positional
Obstructive Sleep Apnea Classification (APOC).
### Methods
A large-scale cross-sectional study was conducted in our sleep center from
2007 to 2018 to analyze the clinical and polysomnography (PSG) data of Chinese
POSA patients. Low ArTH was defined based on PSG indices.
### Results
Of 5,748 OSA patients, 36.80% met the CC criteria, and 42.88% the APOC
criteria, for POSA. The prevalence of POSA was significantly higher in women
than men (40.21% and 46.52% vs. 36.13% and 42.18% for CC and APOC,
respectively). Chinese POSA patients had a lower apnea hypopnea index (AHI)
and lower oxygen desaturation index, shorter duration of oxygen saturation
(SaO 2 ) < 90%, and a higher mean SaO 2 and higher lowest SaO 2 value
compared to subjects with non-positional OSA (NPOSA). More than 40% of the
POSA patients had a low ArTH; the proportion was extremely high in the supine-
isolated-POSA (si-POSA) group and APOC I group. In multivariate logistic
regression analyses, higher mean SaO 2 and lower AHI during sleep were
positive predictors of POSA.
### Conclusions
According to the CC and APOC criteria, more than 1/3 of our Chinese subjects
with OSA had POSA. Chinese POSA patients had less severe OSA and nocturnal
hypoxia. Compared to NPOSA patients, significantly more patients with POSA had
a low ArTH. A low ArTH may be an important endotype in the pathogenesis of
POSA, especially in patients with si-POSA and APOC I. Further studies are
necessary to develop personalized management strategies for POSA patients.
_Trial registration:_ Chinese Clinical Trial Registry; URL: [
http://www.chictr.org.cn ](http://www.chictr.org.cn) ; No. ChiCTR1900025714
(retrospectively registered).
## Introduction
Studies have shown that as many as 9–38% of adults suffer from long-term sleep
disorders [ [ 1 ](/articles/10.1186/s12931-022-02141-3#ref-CR1 "Benjafield AV,
Ayas NT, Eastwood PR, Heinzer R, Ip MSM, Morrell MJ, et al. Estimation of the
global prevalence and burden of obstructive sleep apnoea: a literature-based
analysis. Lancet Respir Med. 2019;7\(8\):687–98.
https://doi.org/10.1016/s2213-2600\(19\)30198-5
.") , [ 2 ](/articles/10.1186/s12931-022-02141-3#ref-CR2 "Senaratna CV, Perret JL, Lodge CJ, Lowe AJ, Campbell BE, Matheson MC, et al. Prevalence of obstructive sleep apnea in the general population: a systematic review. Sleep Med Rev. 2017;34:70–81.
https://doi.org/10.1016/j.smrv.2016.07.002
.") ]. Obstructive sleep apnea (OSA) is a common sleep disorder with serious adverse health consequences [ 3 , 4 , [ 5 ](/articles/10.1186/s12931-022-02141-3#ref-CR5 "Gottlieb DJ, Punjabi NM. Diagnosis and management of obstructive sleep apnea: a review. JAMA. 2020;323\(14\):1389–400.
https://doi.org/10.1001/jama.2020.3514
.") ]. There are currently about 176 million OSA patients in China, with about 66 million classified as moderate to severe [ [ 1 ](/articles/10.1186/s12931-022-02141-3#ref-CR1 "Benjafield AV, Ayas NT, Eastwood PR, Heinzer R, Ip MSM, Morrell MJ, et al. Estimation of the global prevalence and burden of obstructive sleep apnoea: a literature-based analysis. Lancet Respir Med. 2019;7\(8\):687–98.
https://doi.org/10.1016/s2213-2600\(19\)30198-5
.") ]. OSA can be classified as positional OSA (POSA) or non-positional OSA (NPOSA) according to whether the occurrence of respiratory events is associated with the body position during sleep. The Cartwright Classification (CC) is the most commonly used POSA standard [ [ 6 ](/articles/10.1186/s12931-022-02141-3#ref-CR6 "Cartwright RD. Effect of sleep position on sleep apnea severity. Sleep. 1984;7\(2\):110–4.
https://doi.org/10.1093/sleep/7.2.110
.") ], while the Amsterdam Positional Obstructive Sleep Apnea Classification (APOC) is a newer set of classification criteria [ [ 7 ](/articles/10.1186/s12931-022-02141-3#ref-CR7 "Frank MH, Ravesloot MJ, van Maanen JP, Verhagen E, de Lange J, de Vries N. Positional OSA part 1: towards a clinical classification system for position-dependent obstructive sleep apnoea. Sleep Breath. 2015;19\(2\):473–80.
https://doi.org/10.1007/s11325-014-1022-9
.") ].
The results regarding the prevalence of POSA vary between studies with
different criteria and cohorts. According to the CC criteria, Asian studies
showed that 28–80% of OSA in adults is POSA [ 8 , 9 , 10 , 11 , 12 ,
13 , [ 14 ](/articles/10.1186/s12931-022-02141-3#ref-CR14 "Wang X, Luo J,
Huang R, Yi X. Preliminary study on clinical characteristics of Chinese
patients with positional obstructive sleep apnea. Sleep Breath. 2021.
https://doi.org/10.1007/s11325-021-02346-8
.") ], and studies in Western countries showed that the ratio exceeded 50% not only in adults [ [ 7 ](/articles/10.1186/s12931-022-02141-3#ref-CR7 "Frank MH, Ravesloot MJ, van Maanen JP, Verhagen E, de Lange J, de Vries N. Positional OSA part 1: towards a clinical classification system for position-dependent obstructive sleep apnoea. Sleep Breath. 2015;19\(2\):473–80.
https://doi.org/10.1007/s11325-014-1022-9
.") , [ 8 ](/articles/10.1186/s12931-022-02141-3#ref-CR8 "Mador MJ, Kufel TJ, Magalang UJ, Rajesh SK, Watwe V, Grant BJ. Prevalence of positional sleep apnea in patients undergoing polysomnography. Chest. 2005;128\(4\):2130–7.
https://doi.org/10.1378/chest.128.4.2130
.") , 15 , 16 , 17 , 18 , 19 , [ 20 ](/articles/10.1186/s12931-022-02141-3#ref-CR20 "Heinzer R, Petitpierre NJ, Marti-Soler H, Haba-Rubio J. Prevalence and characteristics of positional sleep apnea in the HypnoLaus population-based cohort. Sleep Med. 2018;48:157–62.
https://doi.org/10.1016/j.sleep.2018.02.011
.") ], but also in children [ [ 21 ](/articles/10.1186/s12931-022-02141-3#ref-CR21 "Selvadurai S, Voutsas G, Massicotte C, Kassner A, Katz SL, Propst EJ, et al. Positional obstructive sleep apnea in an obese pediatric population. J Clin Sleep Med. 2020;16\(8\):1295–301.
https://doi.org/10.5664/jcsm.8496
.") ] and the elderly [ [ 22 ](/articles/10.1186/s12931-022-02141-3#ref-CR22 "Iannella G, Magliulo G, Lo Iacono CAM, Bianchi G, Polimeni A, Greco A, et al. Positional obstructive sleep apnea syndrome in elderly patients. Int J Environ Res Public Health. 2020.
https://doi.org/10.3390/ijerph17031120
.") ]. Anatomical and non-anatomical factors contribute differently to OSA between Chinese and Caucasian patients [ [ 23 ](/articles/10.1186/s12931-022-02141-3#ref-CR23 "O’Driscoll DM, Landry SA, Pham J, Young A, Sands SA, Hamilton GS, et al. The physiological phenotype of obstructive sleep apnea differs between Caucasian and Chinese patients. Sleep. 2019.
https://doi.org/10.1093/sleep/zsz186
.") , [ 24 ](/articles/10.1186/s12931-022-02141-3#ref-CR24 "Joosten SA, O’Driscoll DM, Berger PJ, Hamilton GS. Supine position related obstructive sleep apnea in adults: pathogenesis and treatment. Sleep Med Rev. 2014;18\(1\):7–17.
https://doi.org/10.1016/j.smrv.2013.01.005
.") ]. Therefore, the prevalence of POSA in ethnic Chinese populations is likely to differ from that in other races. However, there has been only one previous study of Chinese POSA patients, which used single criterion, had a small sample size and limited subgroup analyses, and did not adjust for confounding factors [ [ 14 ](/articles/10.1186/s12931-022-02141-3#ref-CR14 "Wang X, Luo J, Huang R, Yi X. Preliminary study on clinical characteristics of Chinese patients with positional obstructive sleep apnea. Sleep Breath. 2021.
https://doi.org/10.1007/s11325-021-02346-8
.") ]. Thus, the prevalence of POSA in the general Chinese population, and the characteristics of those with the condition, remain unknown. Due to the increasing socioeconomic burden of OSA in China, it is essential to identify the clinical characteristics of Chinese POSA patients to provide individualized treatment.
It is important to elucidate the pathophysiology of POSA to develop optimal
treatment methods [ [ 25 ](/articles/10.1186/s12931-022-02141-3#ref-CR25
"Taranto-Montemurro L, Messineo L, Wellman A. Targeting endotypic traits with
medications for the pharmacological treatment of obstructive sleep apnea. A
review of the current literature. J Clin Med. 2019.
https://doi.org/10.3390/jcm8111846
.") ]. A low respiratory arousal threshold (ArTH), i.e., easy arousal from sleep in response to relatively mild airway obstruction, is one of the non-anatomical physiological factors associated with OSA [ 26 , 27 , [ 28 ](/articles/10.1186/s12931-022-02141-3#ref-CR28 "Younes M. Role of arousals in the pathogenesis of obstructive sleep apnea. Am J Respir Crit Care Med. 2004;169\(5\):623–33.
https://doi.org/10.1164/rccm.200307-1023OC
.") ]. Patients with a low ArTH are unlikely to be adherent to continuous positive airway pressure (CPAP) treatment [ [ 29 ](/articles/10.1186/s12931-022-02141-3#ref-CR29 "Zinchuk AV, Chu JH, Liang J, Celik Y, de Op Beeck S, Redeker NS, et al. Physiological traits and adherence to sleep apnea therapy in individuals with coronary artery disease. Am J Respir Crit Care Med. 2021;204\(6\):703–12.
https://doi.org/10.1164/rccm.202101-0055OC
.") ]. Therefore, it is important to understand the prevalence and effects of non-anatomical traits in OSA. However, data regarding the pathogenesis of POSA, especially with ArTH, in large clinical populations remain scarce. This large-scale study was performed to evaluate the prevalence, clinical characteristics, and ArTH of POSA patients in China, and to identify possible predictors of POSA.
## Methods
### Subject recruitment
Study subjects were enrolled between May 15, 2007, and December 31, 2018, at
our sleep center as part of the Shanghai Sleep Health Study cohort. This study
was conducted in accordance with the Declaration of Helsinki and the study
protocol was approved by the Ethics Committee of Shanghai Jiao Tong University
Affiliated Sixth People’s Hospital (Approval No: 2019-KY-050[K]). The study
was registered at the Chinese Clinical Trial Registry (No. ChiCTR1900025714).
All subjects provided informed consent.
Ethnic Chinese participants aged ≥ 18 years with snoring or daytime sleepiness
and undergoing laboratory polysomnography (PSG), were screened for eligibility
for inclusion in the study. OSA subjects who had been treated previously or
had other comorbid sleep disorders (insomnia, narcolepsy, upper airway
resistance syndrome, or restless legs syndrome) were excluded. Subjects taking
anxiolytics, antidepressants, antipsychotics, or hypnotic drugs were also
excluded. Data from participants with total sleep time (TST) ≥ 4 h, sleep time
in each position ≥ 30 min, and ≥ 10% of the TST in both the best sleeping
position (BSP) and worst sleeping position (WSP) were considered suitable for
inclusion in the study. All subjects completed a comprehensive questionnaire
pertaining to alcohol consumption, smoking, and medication use, before PSG.
### Clinical evaluation
Height (m), weight (kg), neck circumference (NC) (cm), waist circumference
(WC) (cm), hip circumference (HC) (cm), and blood pressure (mmHg) were
recorded as the mean values of two consecutive measurements before PSG. Body
mass index (BMI) was calculated as weight divided by height squared (kg/m 2
). Fasting blood samples were taken from each subject the morning after PSG.
The glycolipid metabolism index was measured in our laboratory. The
homeostasis model assessment of insulin resistance (HOMA-IR) index was
calculated as fasting insulin (μU/mL) multiplied by fasting glucose (mmol/L)
and the result was divided by 22.5 [ [ 30
](/articles/10.1186/s12931-022-02141-3#ref-CR30 "Bonora E, Targher G,
Alberiche M, Bonadonna RC, Saggiani F, Zenere MB, et al. Homeostasis model
assessment closely mirrors the glucose clamp technique in the assessment of
insulin sensitivity: studies in subjects with various degrees of glucose
tolerance and insulin sensitivity. Diabetes Care. 2000;23\(1\):57–63.
https://doi.org/10.2337/diacare.23.1.57
.") ]. Subjects diagnosed by their physician and using antihypertensive or antiarrhythmic medications were considered to have hypertension or cardiovascular disease (CVD). The diagnoses of diabetes and hyperlipidemia relied on past history and the lipid index, according to the 2016 ESC/EAS Guidelines for the Management of Dyslipidemias [ [ 31 ](/articles/10.1186/s12931-022-02141-3#ref-CR31 "Catapano AL, Graham I, De Backer G, Wiklund O, Chapman MJ, Drexel H, et al. 2016 ESC/EAS guidelines for the management of dyslipidaemias. Eur Heart J. 2016;37\(39\):2999–3058.
https://doi.org/10.1093/eurheartj/ehw272
.") ]. Metabolic syndrome (MS) was defined according to International Diabetes Federation guidelines [ [ 32 ](/articles/10.1186/s12931-022-02141-3#ref-CR32 "Alberti KG, Zimmet P, Shaw J. The metabolic syndrome–a new worldwide definition. Lancet. 2005;366\(9491\):1059–62.
https://doi.org/10.1016/s0140-6736\(05\)67402-8
.") ]. Participants completed the Epworth Sleepiness Scale (ESS). Those with an ESS score > 10 were considered to have excessive daytime sleepiness (EDS) [ [ 33 ](/articles/10.1186/s12931-022-02141-3#ref-CR33 "Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep. 1991;14\(6\):540–5.
https://doi.org/10.1093/sleep/14.6.540
.") ].
### Sleep evaluation and POSA classification
An Alice 4, 5, or 6 Sleep Diagnostic System (Respironics Inc., Pittsburgh, PA,
USA) was used for nocturnal monitoring for full-night laboratory PSG. During
the laboratory-based PSG, electroencephalogram, electrooculogram,
electrocardiogram, and electromyogram recordings were obtained. Nasal airflow
was measured using a nasal pressure cannula, and blood oxygen saturation was
measured by a finger pulse oximeter. A belt containing a piezoelectric
transducer was used to record chest and abdominal movements. An accelerator-
based position sensor placed at the sternum was used to distinguish among the
supine, prone, right, left, and upright positions with simultaneous infrared
video recording (reviewed only in ambiguous cases) [ [ 34
](/articles/10.1186/s12931-022-02141-3#ref-CR34 "Hidalgo Armas L, Ingles S,
Vaca R, Cordero-Guevara J, Duran Carro J, Ullate J, et al. New forehead device
in positional obstructive sleep apnoea: a randomised clinical trial. Thorax.
2021;76\(9\):930–8.
https://doi.org/10.1136/thoraxjnl-2020-216167
.") ]. The video recording was not performed only if the subject refused to provide permission due to the reason of privacy protection. All data were recorded automatically and continuously from 22:00 to 06:00. Two experienced technicians checked the data and output reports manually using Sleepware software (Respironics Inc.) according to the American Academy of Sleep Medicine (AASM) 2007 guidelines [ [ 35 ](/articles/10.1186/s12931-022-02141-3#ref-CR35 "Berry RB, Budhiraja R, Gottlieb DJ, Gozal D, Iber C, Kapur VK, et al. Rules for scoring respiratory events in sleep: update of the 2007 AASM manual for the scoring of sleep and associated events. Deliberations of the sleep apnea definitions task force of the American Academy of Sleep Medicine. J Clin Sleep Med. 2012;8\(5\):597–619.
https://doi.org/10.5664/jcsm.2172
.") ]. Patients with an apnea hypopnea index (AHI) ≥ 5 events/h were included in the OSA group, while subjects with AHI < 5 events/h were considered non-OSA subjects. OSA was classified as mild (AHI ≥ 5, < 15/h), moderate (AHI ≥ 15, < 30/h), severe (AHI ≥ 30, < 55/h), or extremely severe (AHI ≥ 55/h) [ [ 36 ](/articles/10.1186/s12931-022-02141-3#ref-CR36 "Guan J, Yi H, Zou J, Meng L, Tang X, Zhu H, et al. Distinct severity stages of obstructive sleep apnoea are correlated with unique dyslipidaemia: large-scale observational study. Thorax. 2016;71\(4\):347–55.
https://doi.org/10.1136/thoraxjnl-2015-207403
.") ]. Data on AHI in the supine position, AHI in non-supine positions, the microarousal index (MAI), TST, sleep efficacy, proportion of each sleep stage, such as the rapid eye movement (REM) stage and non-rapid eye movement (NREM) stage (consisting of N1, N2, slow wave sleep [SWS], and N3), the time in each position during sleep, oxygen desaturation index (ODI), cumulative time of oxygen saturation < 90% in TST (CT90), mean oxygen saturation (SaO 2 ), and lowest oxygen saturation (LSaO 2 ) were also collected.
The CC criteria for POSA include a supine AHI at least double that of the non-
supine position, and a sleep time in each position ≥ 30 min. If these criteria
are not met, OSA is classified as NPOSA. [ [ 6
](/articles/10.1186/s12931-022-02141-3#ref-CR6 "Cartwright RD. Effect of sleep
position on sleep apnea severity. Sleep. 1984;7\(2\):110–4.
https://doi.org/10.1093/sleep/7.2.110
.") ] We further classified POSA as supine-isolated POSA (si-POSA; AHI ≥ 5/h, supine AHI ≥ 2 non-supine AHI, and non-supine AHI < 5/h) or supine-predominant POSA (sp-POSA; AHI ≥ 5/h, supine AHI ≥ 2 non-supine AHI, and non-supine AHI ≥ 5/h) [ [ 24 ](/articles/10.1186/s12931-022-02141-3#ref-CR24 "Joosten SA, O’Driscoll DM, Berger PJ, Hamilton GS. Supine position related obstructive sleep apnea in adults: pathogenesis and treatment. Sleep Med Rev. 2014;18\(1\):7–17.
https://doi.org/10.1016/j.smrv.2013.01.005
.") ].
The APOC criteria require a sleep time ≥ 10% of the TST in both the BSP and
WSP (APOC I: AHI of BSP < 5/h; APOC II: AHI of BSP in inferior OSA severity
compared to overall AHI; APOC III: AHI of BSP at least 25% lower than the
overall AHI and overall AHI ≥ 40/h) [ [ 7
](/articles/10.1186/s12931-022-02141-3#ref-CR7 "Frank MH, Ravesloot MJ, van
Maanen JP, Verhagen E, de Lange J, de Vries N. Positional OSA part 1: towards
a clinical classification system for position-dependent obstructive sleep
apnoea. Sleep Breath. 2015;19\(2\):473–80.
https://doi.org/10.1007/s11325-014-1022-9
.") , [ 37 ](/articles/10.1186/s12931-022-02141-3#ref-CR37 "Ravesloot MJ, Frank MH, van Maanen JP, Verhagen EA, de Lange J, de Vries N. Positional OSA part 2: retrospective cohort analysis with a new classification system \(APOC\). Sleep Breath. 2016;20\(2\):881–8.
https://doi.org/10.1007/s11325-015-1206-y
.") ].
### ArTH
Edwards et al. established a clinical screening tool for low ArTH based on
three criteria: AHI < 30/h, LSaO 2 > 82.5%, and proportion of hypopneas >
58.3% [ [ 38 ](/articles/10.1186/s12931-022-02141-3#ref-CR38 "Edwards BA,
Eckert DJ, McSharry DG, Sands SA, Desai A, Kehlmann G, et al. Clinical
predictors of the respiratory arousal threshold in patients with obstructive
sleep apnea. Am J Respir Crit Care Med. 2014;190\(11\):1293–300.
https://doi.org/10.1164/rccm.201404-0718OC
.") ]. Each fulfilled criterion is scored as 1, and a total score ≥ 2 is taken to indicate a low ArTH. This tool is widely used and does not require epiglottic measurements, thus allowing analyses of large retrospective datasets [ 39 , 40 , [ 41 ](/articles/10.1186/s12931-022-02141-3#ref-CR41 "Lee RWW, Sutherland K, Sands SA, Edwards BA, Chan TO, et al. Differences in respiratory arousal threshold in Caucasian and Chinese patients with obstructive sleep apnoea. Respirology. 2017;22\(5\):1015–21.
https://doi.org/10.1111/resp.13022
.") ]. The equation for determining the ArTH is as follows (where male sex = 1 and female sex = 0:
$$ArTH=-65.39+\left(0.06*age\right)+\left(3.69*sex\right)-\left(0.03*BMI\right)-\left(0.11*AHI\right)+\left(0.53*LSaO2\right)+
(0.09*proportion of hypopneas)$$
### Statistical analysis
The sample size was determined based on power analysis. With a power of 90%
and α of 0.05, 2,300 participants were required. The Kolmogorov–Smirnov test
was used to verify the normality of the data distribution. Continuous
variables with a normal distribution are shown as means ± standard deviation,
while skewed data are presented as the median (first to third quartile).
Categorical data are presented as percentages. The data were further analyzed
by ANOVA, _t_ test, Kruskal–Wallis test, and the χ 2 test. Logistic
regression analyses were performed to identify predictors of POSA, and the
association between ArTH and POSA. Age, BMI, sex, NC, WC, HC, alcohol
consumption, smoking, TST, ESS, MAI, and CT90 were included as potential
confounding factors. Statistical analyses were performed using SPSS software
(version 25.0; IBM Corp., Armonk, NY, USA). In all analyses, _P_ < 0.05 was
taken to indicate statistical significance.
## Results
### Prevalence of POSA
Of the 9,171 patients in our study cohort with suspected OSA between May 15,
2007, and December 31, 2018, 2,061 were excluded due to inappropriate age (<
18 years, _n_ = 246), TST < 4 h ( _n_ = 560), < 30 min spent in the supine or
non-supine position ( _n_ = 1,042), the presence of comorbid sleep disorders (
_n_ = 62), and taking anxiolytics, antidepressants, hypnotics, or
antipsychotic drugs ( _n_ = 121). Therefore, the final study sample consisted
of 7,110 patients (Fig. [ 1 ](/articles/10.1186/s12931-022-02141-3#Fig1) ) of
whom the clinical and sleep characteristics were showed in Additional file [ 2
](/articles/10.1186/s12931-022-02141-3#MOESM2) : Table S1. Of the 5,748 OSA
patients, 36.80% met the CC criteria, and 42.88% the APOC criteria, for POSA
(Fig. [ 2 ](/articles/10.1186/s12931-022-02141-3#Fig2) ). The prevalence of
POSA was significantly higher in women than men according to both the CC
(Table [ 1 ](/articles/10.1186/s12931-022-02141-3#Tab1) ) and APOC (Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) ) criteria (40.21% and 46.52% in
women vs. 36.13%, 42.18% in men, respectively). According to the CC and APOC
criteria, the male to female ratios were 8.36:1 and 7.73:1 for extremely
severe POSA, and 3.11:1 and 2.94:1 for mild OSA, respectively (Fig. [ 3
](/articles/10.1186/s12931-022-02141-3#Fig3) ). The male to female ratio of
POSA increased with increasing AHI. The prevalence of POSA decreased
significantly with increasing AHI (Fig. [ 4
](/articles/10.1186/s12931-022-02141-3#Fig4) a, c) with similar trends
according to both the CC and APOC criteria. The prevalence of si-POSA was
higher in mild OSA than sp-POSA (Fig. [ 4
](/articles/10.1186/s12931-022-02141-3#Fig4) b). APOC I was associated with
milder AHI than APOC II and III (Fig. [ 4
](/articles/10.1186/s12931-022-02141-3#Fig4) d). The APOC grade increased with
AHI and nocturnal hypoxia severity.
**Fig. 1**
[ 
](/articles/10.1186/s12931-022-02141-3/figures/1)
Flow diagram of the recruitment process. _NOSA_ non-obstructive sleep apnea,
_OSA_ obstructive sleep apnea, _PSG_ polysomnography, _TST_ total sleep time
[ Full size image ](/articles/10.1186/s12931-022-02141-3/figures/1)
**Fig. 2**
[ 
](/articles/10.1186/s12931-022-02141-3/figures/2)
Prevalence of CC-POSA **a** and APOC-POSA **b** in different OSA severity
groups. _AHI_ apnea–hypopnea index, _APOC_ Amsterdam Positional Obstructive
Sleep Apnea Classification, _CC_ Cartwright Classification, _POSA_ positional
obstructive sleep apnea, _si-POSA_ supine-isolated positional obstructive
sleep apnea, _sp-POSA_ supine-predominant positional obstructive sleep apnea
[ Full size image ](/articles/10.1186/s12931-022-02141-3/figures/2)
**Table 1 Clinical and Sleep Characteristics of OSA Subjects (n = 5748)
according to CC**
[ Full size table ](/articles/10.1186/s12931-022-02141-3/tables/1)
**Table 2 Clinical and Sleep Characteristics of OSA Subjects (n = 5748)
according to APOC**
[ Full size table ](/articles/10.1186/s12931-022-02141-3/tables/2)
**Fig. 3**
[ 
](/articles/10.1186/s12931-022-02141-3/figures/3)
Male to female ratio of OSA and POSA subjects in different OSA severity
groups. _AHI_ apnea–hypopnea index, _APOC_ Amsterdam Positional Obstructive
Sleep Apnea Classification; _CC_ Cartwright Classification, _OSA_ obstructive
sleep apnea, _POSA_ positional obstructive sleep apnea, _si-POSA_ supine-
isolated positional obstructive sleep apnea, _sp-POSA_ supine-predominant
positional obstructive sleep apnea
[ Full size image ](/articles/10.1186/s12931-022-02141-3/figures/3)
**Fig. 4**
[ 
](/articles/10.1186/s12931-022-02141-3/figures/4)
Treads in the proportions of POSA subjects with AHI **a** CC-POSA and CC-
NPOSA, **b** Si-POSA and sp-POSA, **c** APOC-POSA and APOC-NPOSA, **d** APOC
I, APOC II and APOC III. _AHI_ apnea–hypopnea index, _APOC_ Amsterdam
Positional Obstructive Sleep Apnea Classification, _CC_ Cartwright
Classification, _NPOSA_ non-positional obstructive sleep apnea, _POSA_
positional obstructive sleep apnea, _si-POSA_ supine-isolated positional
obstructive sleep apnea, _sp-POSA_ supine-predominant positional obstructive
sleep apnea
[ Full size image ](/articles/10.1186/s12931-022-02141-3/figures/4)
### Comparison between POSA and NPOSA according to the CC and APOC criteria
Chinese POSA patients had lower AHI, ODI, and CT90 values, and higher mean SaO
2 and LSaO 2 values, than NPOSA patients during sleep. The overall AHI,
supine AHI, non-supine AHI, REM AHI, and NREM AHI values were lower in the
POSA group (all _P_ < 0.001), indicating less severe OSA compared to the NPOSA
group according to both the CC (Table [ 1
](/articles/10.1186/s12931-022-02141-3#Tab1) ) and APOC (Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) ) criteria. Compared to the NPOSA
group, the ODI and CT90 values were lower, and the mean SaO 2 and LSaO 2
were higher, in the POSA group, indicating less severe nocturnal hypoxia in
the latter group according to both the CC (Table [ 1
](/articles/10.1186/s12931-022-02141-3#Tab1) , Fig. [ 5
](/articles/10.1186/s12931-022-02141-3#Fig5) a, b) and APOC (Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) , Fig. [ 5
](/articles/10.1186/s12931-022-02141-3#Fig5) c, d) criteria.
**Fig. 5**
[ 
](/articles/10.1186/s12931-022-02141-3/figures/5)
Treads in the proportions of POSA subjects with LSaO2 **a** CC-POSA and CC-
NPOSA, **b** Si-POSA and sp-POSA, **c** APOC-POSA and APOC-NPOSA, **d** APOC
I, APOC II and APOC III. _APOC_ Amsterdam Positional Obstructive Sleep Apnea
Classification, _CC_ Cartwright Classification, _LSaO2_ lowest oxygen
saturation, _NPOSA_ non-positional obstructive sleep apnea, _POSA_ positional
obstructive sleep apnea, _si-POSA_ supine-isolated positional obstructive
sleep apnea, _sp-POSA_ supine-predominant positional obstructive sleep apnea
[ Full size image ](/articles/10.1186/s12931-022-02141-3/figures/5)
In further subgroup analyses, the si-POSA group had lower overall AHI, REM
AHI, NREM AHI, supine AHI, non-supine AHI, ODI, and CT90 values, and higher
mean SaO 2 and LSaO 2 values, than the sp-POSA group (Table [ 1
](/articles/10.1186/s12931-022-02141-3#Tab1) ). In subgroup analyses of APOC,
the APOC I group had the lowest overall AHI, REM AHI, NREM AHI, and AHI values
in the supine and non-supine positions (Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) ). ODI and CT90 were lowest, and
the mean SaO 2 and LSaO 2 were highest, in the APOC I group, indicating
that nocturnal hypoxia was less severe than in the other APOC subgroups (Table
[ 2 ](/articles/10.1186/s12931-022-02141-3#Tab2) ).
Subjects with POSA were less likely to feel sleepy and experience EDS, while
the si-POSA (Table [ 1 ](/articles/10.1186/s12931-022-02141-3#Tab1) ) and APOC
I (Table [ 2 ](/articles/10.1186/s12931-022-02141-3#Tab2) ) groups had low
proportions of EDS. The POSA group had a lower BMI than the NPOSA group
(26.47kg/m 2 [24.51–28.73]kg/m 2 vs. 27.51kg/m 2 [25.15–30.03]kg/m 2
and 26.49kg/m 2 [24.56–28.73]kg/m 2 vs. 27.64kg/m 2 [25.17–30.07]kg/m 2
for CC [Table [ 1 ](/articles/10.1186/s12931-022-02141-3#Tab1) ] and APOC
[Table [ 2 ](/articles/10.1186/s12931-022-02141-3#Tab2) ], respectively). As
shown in Table [ 1 ](/articles/10.1186/s12931-022-02141-3#Tab1) , the si-POSA
group had a lower BMI than the sp-POSA group, and the BMI was lower in the
APOC I group than the other APOC subgroups (Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) ). As BMI increased, the
prevalence of POSA decreased (Additional file [ 1
](/articles/10.1186/s12931-022-02141-3#MOESM1) : Fig. S1), especially in the
si-POSA and APOC I groups.
With regard to sleep structure, the percentages of SWS and REM stage sleep
were significantly higher in the POSA than NPOSA group according to the CC
(Table [ 1 ](/articles/10.1186/s12931-022-02141-3#Tab1) ) and APOC (Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) ) criteria ( _P_ < 0.01 for SWS,
_P < _ 0.05 for REM stage sleep [for both criteria sets]). Furthermore, the
si-POSA group had a higher percentage of SWS and lower percentage of N1 stage
sleep than the sp-POSA group. Meanwhile, the percentage of SWS was
significantly higher, and the percentage of N1 stage sleep was significantly
lower, in the APOC I group than APOC II and APOC III groups. The POSA group
had a shorter TST and lower sleep efficiency according to the CC (Table [ 1
](/articles/10.1186/s12931-022-02141-3#Tab1) ) and APOC (Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) ) criteria (all _P_ < 0.001). The
APOC III group had a significantly higher percentage of supine sleep than the
APOC I and APOC II groups (Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) ).
### ArTH
A low ArTH was more common in females than males (Table [ 1
](/articles/10.1186/s12931-022-02141-3#Tab1) and Table [ 2
](/articles/10.1186/s12931-022-02141-3#Tab2) ). The POSA group had a higher
absolute fraction of hypopneas. The percentages of AHI < 30 events/h, LSaO 2
> 82.5%, and hypopnea proportion > 58.3%, were higher in the POSA than NPOSA
group, and higher in the si-POSA than sp-POSA group. In the si-POSA and sp-
POSA groups, the proportions of low ArTH (71.13% and 31.86%, respectively)
were significantly higher compared to the NPOSA group (22.85%) (Table [ 1
](/articles/10.1186/s12931-022-02141-3#Tab1) ). The APOC I group had the
highest proportion of low ArTH (71.57%) among the three APOC subgroups (Table
[ 2 ](/articles/10.1186/s12931-022-02141-3#Tab2) ).
The results of binary logistic regression analysis of the association between
POSA and low ArTH are shown in Table [ 3
](/articles/10.1186/s12931-022-02141-3#Tab3) . In the model adjusted for age,
BMI, and sex, si-POSA (adjusted odds ratio [OR], 7.302; 95% confidence
interval [CI], 6.090–8.757; P < 0.001) and sp-POSA (adjusted OR, 1.567; 95%
CI, 1.357–1.809) were significantly associated with the development of low
ArTH. In a model adjusted for more potential confounders, si-POSA (adjusted
OR, 3.542; 95% CI, 2.862–4.384; P < 0.001) was still significantly associated
with the development of low ArTH, although significance disappeared for sp-
POSA. With regard to APOC (Table [ 3
](/articles/10.1186/s12931-022-02141-3#Tab3) ), APOC I (adjusted OR, 3.900;
95% CI, 3.141–4.842) and II (adjusted OR, 1.287; 95% CI, 1.091–1.518) were
associated with a higher likelihood of a low ArTH after adjustment for
confounding factors, while APOC III was not (adjusted OR, 0.143; 95% CI,
0.062–0.330).
**Table 3 Adjusted ORs and 95% CIs for the Association between POSA and ArTH
according to CC and APOC**
[ Full size table ](/articles/10.1186/s12931-022-02141-3/tables/3)
### POSA predictors
Univariate and multivariate regression analyses demonstrated that a higher
mean SaO 2 (adjusted OR, 1.099; 95% CI, 1.063–1.136 for CC; and adjusted OR,
1.086; 95% CI, 1.053–1.120 for APOC) and lower AHI (adjusted OR, 0.967; 95%
CI, 0.960–0.973 for CC; and adjusted OR, 0.968; 95% CI, 0.961–0.974 for APOC)
were positive predictors of POSA (Table [ 4
](/articles/10.1186/s12931-022-02141-3#Tab4) ). Table [ 5
](/articles/10.1186/s12931-022-02141-3#Tab5) shows the results of binary
logistic regression analysis of the associations among mean SaO 2 , AHI, and
POSA. Compared to AHI ≥ 55/h, mild OSA (5 ≤ AHI < 15/h), moderate OSA (15 ≤
AHI < 30/h) and 30 ≤ AHI < 55/h were more likely to be associated with POSA
according to the CC (adjusted OR, 4.174; 95% CI, 3.238–5.380; adjusted OR,
4.818; 95% CI, 3.826–6.066; and adjusted OR, 3.643; 95% CI, 2.977–4.457,
respectively). Similar results were found for APOC (adjusted OR, 3.400; 95%
CI, 2.673–4.325; adjusted OR, 5.127; 95% CI, 4.121–6.379; and adjusted OR,
3.399; 95% CI, 2.822–4.095, respectively) (Table [ 5
](/articles/10.1186/s12931-022-02141-3#Tab5) ). After adjusting for potential
confounders, OSA patients with a mean SaO 2 > 95% were 49.5% (OR, 1.495 [95%
CI, 1.075–2.080]) and 44.3% (OR, 1.443 [95% CI, 1.053–1.976]) more likely to
have POSA according to CC or APOC, respectively, than those with a mean SaO 2
< 92% (Table [ 5 ](/articles/10.1186/s12931-022-02141-3#Tab5) ).
**Table 4 Adjusted ORs and 95% CIs for the Association Between Predictors and
POSA according to CC and APOC**
[ Full size table ](/articles/10.1186/s12931-022-02141-3/tables/4)
**Table 5 Adjusted ORs and 95% CIs for the Association Between AHI / Mean SaO2
and POSA according to CC and APOC**
[ Full size table ](/articles/10.1186/s12931-022-02141-3/tables/5)
## Discussion
To our knowledge, this is the first study to analyze the clinical
characteristics and ArTH of Chinese POSA patients according to both the CC and
APOC criteria, and the prevalence of the disease in a large Chinese sample.
More than 1/3 of the OSA subjects met the CC or APOC criteria for POSA,
representing a lower prevalence than in Western studies. In addition, more
than 40% of the POSA patients had a low ArTH. The proportion was extremely
high in the si-POSA and APOC I groups.
Compared to NPOSA, POSA patients are less obese and have less severe OSA [ [ 8
](/articles/10.1186/s12931-022-02141-3#ref-CR8 "Mador MJ, Kufel TJ, Magalang
UJ, Rajesh SK, Watwe V, Grant BJ. Prevalence of positional sleep apnea in
patients undergoing polysomnography. Chest. 2005;128\(4\):2130–7.
https://doi.org/10.1378/chest.128.4.2130
.") , [ 10 ](/articles/10.1186/s12931-022-02141-3#ref-CR10 "Lee SA, Paek JH, Chung YS, Kim WS. Clinical features in patients with positional obstructive sleep apnea according to its subtypes. Sleep Breath. 2017;21\(1\):109–17.
https://doi.org/10.1007/s11325-016-1379-z
.") , [ 13 ](/articles/10.1186/s12931-022-02141-3#ref-CR13 "Mo JH, Lee CH, Rhee CS, Yoon IY, Kim JW. Positional dependency in Asian patients with obstructive sleep apnea and its implication for hypertension. Arch Otolaryngol Head Neck Surg. 2011;137\(8\):786–90.
https://doi.org/10.1001/archoto.2011.122
.") , [ 24 ](/articles/10.1186/s12931-022-02141-3#ref-CR24 "Joosten SA, O’Driscoll DM, Berger PJ, Hamilton GS. Supine position related obstructive sleep apnea in adults: pathogenesis and treatment. Sleep Med Rev. 2014;18\(1\):7–17.
https://doi.org/10.1016/j.smrv.2013.01.005
.") ]. Certain craniofacial characteristics, such as retrognathia, have been shown to promote upper airway obstruction in Chinese patients regardless of BMI. Cephalometric studies reported a shorter cranial base, maxilla, and mandible in Chinese OSA patients [ [ 42 ](/articles/10.1186/s12931-022-02141-3#ref-CR42 "Lee RW, Vasudavan S, Hui DS, Prvan T, Petocz P, Darendeliler MA, et al. Differences in craniofacial structures and obesity in Caucasian and Chinese patients with obstructive sleep apnea. Sleep. 2010;33\(8\):1075–80.
https://doi.org/10.1093/sleep/33.8.1075
.") ], along with a more posteriorly positioned mandible and inferiorly positioned hyoid bone, and an enlarged tongue and soft palate, compared to Caucasian OSA patients [ [ 43 ](/articles/10.1186/s12931-022-02141-3#ref-CR43 "Hui DSC, Ko FWS, Chu ASY, Fok JPC, Chan MCH, Li TST, et al. Cephalometric assessment of craniofacial morphology in Chinese patients with obstructive sleep apnoea. Respir Med. 2003;97\(6\):640–6.
https://doi.org/10.1053/rmed.2003.1494
.") ]. One study found that the maximum esophageal pressure was significantly higher in Asians than Caucasians [ [ 44 ](/articles/10.1186/s12931-022-02141-3#ref-CR44 "Ong KC, Clerk AA. Comparison of the severity of sleep-disordered breathing in Asian and Caucasian patients seen at a sleep disorders center. Respir Med. 1998;92\(6\):843–8.
https://doi.org/10.1016/s0954-6111\(98\)90386-9
.") ]. These findings have been attributed to the greater craniofacial restriction seen in Asians [ [ 42 ](/articles/10.1186/s12931-022-02141-3#ref-CR42 "Lee RW, Vasudavan S, Hui DS, Prvan T, Petocz P, Darendeliler MA, et al. Differences in craniofacial structures and obesity in Caucasian and Chinese patients with obstructive sleep apnea. Sleep. 2010;33\(8\):1075–80.
https://doi.org/10.1093/sleep/33.8.1075
.") ]. A smaller upper airway is more likely to collapse, thereby promoting OSA in both the supine and non-supine positions [ [ 45 ](/articles/10.1186/s12931-022-02141-3#ref-CR45 "Schorr F, Kayamori F, Hirata RP, Danzi-Soares NJ, Gebrim EM, Moriya HT, et al. Different craniofacial characteristics predict upper airway collapsibility in Japanese-Brazilian and white men. Chest. 2016;149\(3\):737–46.
https://doi.org/10.1378/chest.15-0638
.") ].
In POSA, respiratory events generally cease, accompanied by cortical arousal.
Respiratory arousal during sleep can prevent apnea and may even be lifesaving
[ [ 41 ](/articles/10.1186/s12931-022-02141-3#ref-CR41 "Lee RWW, Sutherland K,
Sands SA, Edwards BA, Chan TO, et al. Differences in respiratory arousal
threshold in Caucasian and Chinese patients with obstructive sleep apnoea.
Respirology. 2017;22\(5\):1015–21.
https://doi.org/10.1111/resp.13022
.") , [ 46 ](/articles/10.1186/s12931-022-02141-3#ref-CR46 "Gleeson K, Zwillich CW, White DP. The influence of increasing ventilatory effort on arousal from sleep. Am Rev Respir Dis. 1990;142\(2\):295–300.
https://doi.org/10.1164/ajrccm/142.2.295
.") ]. However, low ArTH prevents deeper sleep stages (SWS) with stable breathing, and leads to ventilatory instability with sleep fragmentation even under conditions of mild upper airway obstruction [ [ 28 ](/articles/10.1186/s12931-022-02141-3#ref-CR28 "Younes M. Role of arousals in the pathogenesis of obstructive sleep apnea. Am J Respir Crit Care Med. 2004;169\(5\):623–33.
https://doi.org/10.1164/rccm.200307-1023OC
.") , [ 47 ](/articles/10.1186/s12931-022-02141-3#ref-CR47 "Younes M. Role of respiratory control mechanisms in the pathogenesis of obstructive sleep disorders. J Appl Physiol. 2008;105\(5\):1389–405.
https://doi.org/10.1152/japplphysiol.90408.2008
.") , [ 48 ](/articles/10.1186/s12931-022-02141-3#ref-CR48 "Younes M, Ostrowski M, Thompson W, Leslie C, Shewchuk W. Chemical control stability in patients with obstructive sleep apnea. Am J Respir Crit Care Med. 2001;163\(5\):1181–90.
https://doi.org/10.1164/ajrccm.163.5.2007013
.") ]. Premature arousal results in inadequate chemical stimuli for activation of the upper airway dilator muscles [ [ 28 ](/articles/10.1186/s12931-022-02141-3#ref-CR28 "Younes M. Role of arousals in the pathogenesis of obstructive sleep apnea. Am J Respir Crit Care Med. 2004;169\(5\):623–33.
https://doi.org/10.1164/rccm.200307-1023OC
.") ]. Therefore, a low ArTH is an important endotype in the pathogenesis of POSA [ [ 27 ](/articles/10.1186/s12931-022-02141-3#ref-CR27 "Eckert DJ, White DP, Jordan AS, Malhotra A, Wellman A. Defining phenotypic causes of obstructive sleep apnea. Identification of novel therapeutic targets. Am J Respir Crit Care Med. 2013;188\(8\):996–1004.
https://doi.org/10.1164/rccm.201303-0448OC
.") ].
Non-obese OSA patients, who have a high prevalence of low ArTH, also tend to
have less collapsible upper airways and less severe OSA. The characteristics
of these patients are identical to those of POSA patients [ [ 49
](/articles/10.1186/s12931-022-02141-3#ref-CR49 "Gray EL, McKenzie DK, Eckert
DJ. Obstructive sleep apnea without obesity is common and difficult to treat:
evidence for a distinct pathophysiological phenotype. J Clin Sleep Med.
2017;13\(1\):81–8.
https://doi.org/10.5664/jcsm.6394
.") ]. Strategies to increase the ArTH have the potential to make breathing more stable during sleep. Previous studies showed that increasing the ArTH through pharmacological interventions can reduce OSA severity, particularly in patients with a low initial ArTH [ [ 50 ](/articles/10.1186/s12931-022-02141-3#ref-CR50 "Eckert DJ, Owens RL, Kehlmann GB, Wellman A, Rahangdale S, Yim-Yeh S, et al. Eszopiclone increases the respiratory arousal threshold and lowers the apnoea/hypopnoea index in obstructive sleep apnoea patients with a low arousal threshold. Clin Sci \(Lond\). 2011;120\(12\):505–14.
https://doi.org/10.1042/cs20100588
.") ]. Compared to Caucasians, Asians are less likely to exhibit a low ArTH [ [ 41 ](/articles/10.1186/s12931-022-02141-3#ref-CR41 "Lee RWW, Sutherland K, Sands SA, Edwards BA, Chan TO, et al. Differences in respiratory arousal threshold in Caucasian and Chinese patients with obstructive sleep apnoea. Respirology. 2017;22\(5\):1015–21.
https://doi.org/10.1111/resp.13022
.") ]. The findings suggest that genetic background is likely a key factor underlying pathophysiological traits that are predisposing factors for OSA [ [ 51 ](/articles/10.1186/s12931-022-02141-3#ref-CR51 "Zinchuk A, Edwards BA, Jeon S, Koo BB, Concato J, Sands S, et al. Prevalence, associated clinical features, and impact on continuous positive airway pressure use of a low respiratory arousal threshold among male United States veterans with obstructive sleep apnea. J Clin Sleep Med. 2018;14\(5\):809–17.
https://doi.org/10.5664/jcsm.7112
.") ]. This is supported by emerging evidence that compromised upper airway anatomy in Asians is predominantly due to a restriction caused by the craniofacial skeletal structure, whereas in African-Americans it is primarily due to enlargement of upper airway soft tissues in the setting of obesity as well as non-anatomical factors [ [ 52 ](/articles/10.1186/s12931-022-02141-3#ref-CR52 "Sutherland K, Lee RW, Cistulli PA. Obesity and craniofacial structure as risk factors for obstructive sleep apnoea: impact of ethnicity. Respirology. 2012;17\(2\):213–22.
https://doi.org/10.1111/j.1440-1843.2011.02082.x
.") ].
A low ArTH may be significant factor in terms of the pathogenesis of OSA in
nonobese patients, and is a strong predictor of poor compliance with long-term
CPAP use. This emphasizes the importance of understanding the
pathophysiological phenotype of OSA for treatment management and enhanced CPAP
compliance [ [ 49 ](/articles/10.1186/s12931-022-02141-3#ref-CR49 "Gray EL,
McKenzie DK, Eckert DJ. Obstructive sleep apnea without obesity is common and
difficult to treat: evidence for a distinct pathophysiological phenotype. J
Clin Sleep Med. 2017;13\(1\):81–8.
https://doi.org/10.5664/jcsm.6394
.") ]. In one study, at least one-third of OSA patients had low ArTH levels [ [ 53 ](/articles/10.1186/s12931-022-02141-3#ref-CR53 "Eckert DJ. Phenotypic approaches to obstructive sleep apnoea—new pathways for targeted therapy. Sleep Med Rev. 2018;37:45–59.
https://doi.org/10.1016/j.smrv.2016.12.003
.") ]. In the present study, over 40% of the POSA patients had low ArTH levels. POSA is generally less severe, and this finding may explain why POSA patients have poorer compliance with CPAP treatment [ [ 49 ](/articles/10.1186/s12931-022-02141-3#ref-CR49 "Gray EL, McKenzie DK, Eckert DJ. Obstructive sleep apnea without obesity is common and difficult to treat: evidence for a distinct pathophysiological phenotype. J Clin Sleep Med. 2017;13\(1\):81–8.
https://doi.org/10.5664/jcsm.6394
.") , [ 54 ](/articles/10.1186/s12931-022-02141-3#ref-CR54 "McNicholas WT, Bonsignore MR, Lévy P, Ryan S. Mild obstructive sleep apnoea: clinical relevance and approaches to management. Lancet Respir Med. 2016;4\(10\):826–34.
https://doi.org/10.1016/s2213-2600\(16\)30146-1
.") ].
Our patients with a higher mean SaO 2 (> 95%) during sleep and mild-to-
moderate OSA were more likely to have POSA. Women with OSA had a higher
likelihood of POSA, especially those in the si-POSA and APOC I groups,
suggesting that women may benefit more from positional therapy. Although
positional therapy alone will not resolve upper airway obstruction in the
majority of OSA patients, it could be combined with treatments that improve
ArTH and loop gain as an alternative to CPAP in certain POSA patients [ [ 55
](/articles/10.1186/s12931-022-02141-3#ref-CR55 "Joosten SA, Edwards BA,
Wellman A, Turton A, Skuza EM, Berger PJ, et al. The effect of body position
on physiological factors that contribute to obstructive sleep apnea. Sleep.
2015;38\(9\):1469–78.
https://doi.org/10.5665/sleep.4992
.") ]. Eszopiclone, zopiclone, and zolpidem were found to increase ArTH in previous randomized controlled trials [ [ 25 ](/articles/10.1186/s12931-022-02141-3#ref-CR25 "Taranto-Montemurro L, Messineo L, Wellman A. Targeting endotypic traits with medications for the pharmacological treatment of obstructive sleep apnea. A review of the current literature. J Clin Med. 2019.
https://doi.org/10.3390/jcm8111846
.") , [ 56 ](/articles/10.1186/s12931-022-02141-3#ref-CR56 "Messineo L, Eckert DJ, Lim R, Chiang A, Azarbarzin A, Carter SG, et al. Zolpidem increases sleep efficiency and the respiratory arousal threshold without changing sleep apnoea severity and pharyngeal muscle activity. J Physiol. 2020;598\(20\):4681–92.
https://doi.org/10.1113/jp280173
.") ]. Therefore, these medications may improve compliance with CPAP therapy in POSA patients.
The present study had a number of strengths, including analysis of most of the
relevant clinical and PSG characteristics of POSA patients, and the
performance of full-night PSG in the laboratory. Moreover, the CC and APOC
criteria were both applied, with adjustment for potential confounding factors
to avoid false-negative results. Finally, the large sample size allowed full
subgroup analyses.
However, this study also had some limitations. First, it could only
demonstrate an association between POSA and ArTH due to its observational
design. As epiglottic pressure measurement (the gold standard ArTH evaluation)
is extremely difficult in a large-scale study, a validated clinical screening
tool was used for subgroup analyses, and to determine subtle clinical
associations. Although this screening tool is widely accepted, it was
developed in a largely non-ethnic Chinese population and the potential for
bias effect should be acknowledged. The equation proposed for calculating ArTH
may not be applicable to other populations, as the role of ArTH in the
pathogenesis and treatment of OSA may vary by morphology, age, and ethnicity [
[ 41 ](/articles/10.1186/s12931-022-02141-3#ref-CR41 "Lee RWW, Sutherland K,
Sands SA, Edwards BA, Chan TO, et al. Differences in respiratory arousal
threshold in Caucasian and Chinese patients with obstructive sleep apnoea.
Respirology. 2017;22\(5\):1015–21.
https://doi.org/10.1111/resp.13022
.") ]. As the major determinants of OSA severity in Chinese patients are anatomical, rather than non-anatomical, the ArTH may have been slightly overestimated for a given level of OSA severity which is similar in non-ethnic Chinese population. Our indirect estimations of ArTH should be verified via invasive measurements directly in ethnic Chinese subjects. Also, POSA was diagnosed based on recordings performed for only 1 night, where considerable night-to-night variability in respiratory events has been reported; OSA severity (according to ODI) changed in 77.9% of patients [ [ 57 ](/articles/10.1186/s12931-022-02141-3#ref-CR57 "Stöberl AS, Schwarz EI, Haile SR, Turnbull CD, Rossi VA, Stradling JR, et al. Night-to-night variability of obstructive sleep apnea. J Sleep Res. 2017;26\(6\):782–8.
https://doi.org/10.1111/jsr.12558
.") ]. And 19.7% of subjects were misdiagnosed when using an ODI cutoff of 15 events/h during single-night PSG [ [ 58 ](/articles/10.1186/s12931-022-02141-3#ref-CR58 "Roeder M, Sievi NA, Bradicich M, Grewe FA, Siegfried S, Gaisl T, et al. The accuracy of repeated sleep studies in OSA: a longitudinal observational study with 14 nights of oxygen saturation monitoring. Chest. 2021;159\(3\):1222–31.
https://doi.org/10.1016/j.chest.2020.09.098
.") ]. The intraindividual variability (indicated by the coefficient of variation) was > 30%, allowing for the identification of a relevant number of OSA patients who would have been misdiagnosed or misclassified with single-night sleep study [ [ 57 ](/articles/10.1186/s12931-022-02141-3#ref-CR57 "Stöberl AS, Schwarz EI, Haile SR, Turnbull CD, Rossi VA, Stradling JR, et al. Night-to-night variability of obstructive sleep apnea. J Sleep Res. 2017;26\(6\):782–8.
https://doi.org/10.1111/jsr.12558
.") , [ 58 ](/articles/10.1186/s12931-022-02141-3#ref-CR58 "Roeder M, Sievi NA, Bradicich M, Grewe FA, Siegfried S, Gaisl T, et al. The accuracy of repeated sleep studies in OSA: a longitudinal observational study with 14 nights of oxygen saturation monitoring. Chest. 2021;159\(3\):1222–31.
https://doi.org/10.1016/j.chest.2020.09.098
.") ]. As OSA severity exhibits a considerable night-to-night variability, the sleep position that determines the phenotype of POSA might show similar variability. Recording the sleeping position for several consecutive nights may be necessary to confirm the POSA phenotype. Nonetheless, this study adds to the literature by shedding light on the prevalence of POSA in China, and the clinical characteristics and ArTH of Chinese POSA patients.
## Conclusion
Among the subjects with OSA included in this study, 36.80% and 42.88% met the
CC and APOC criteria for POSA, respectively. Chinese POSA patients had less
severe OSA and nocturnal hypoxia compared to the si-POSA and APOC I groups. In
comparison with NPOSA patients, significantly more patients with POSA had a
low ArTH. A low ArTH may be an important endotype in the pathogenesis of POSA.
Further studies are necessary to develop personalized management strategies
for patients with POSA.
## Current knowledge/study rationale
There is strong evidence that the severity of obstructive sleep apnea (OSA)
can worsen when sleeping in the supine position, which is known as positional
OSA (POSA). While POSA is prevalent among adults, there are limited data on
the presence and characteristics of POSA in China. In addition, studies of
large clinical populations examining how the respiratory arousal threshold
(ArTH), a key physiological trait, is involved in the pathogenesis of POSA,
which may influence adherence to continuous positive airway pressure (CPAP),
are lacking. This study was performed to assess the prevalence,
characteristics, and ArTH of POSA in a large Chinese cohort.
## Study impact
More than 1/3 of our Chinese subjects with OSA had POSA, which was especially
prevalent among those with mild OSA. The rate was lower than in Western
studies because of the differences in anatomical and non-anatomical factors
between Chinese and Western populations. A low ArTH is more common in patients
with POSA compared to those with non-positional OSA (NPOSA). These data
suggest that millions of Chinese people have POSA, where assessment of ArTH
can help identify patients at risk of poor CPAP adherence, and may inform the
selection of targeted therapy to improve CPAP use. Personalized treatment,
such as the use of positional therapy devices, should be considered when
treating POSA, and may be beneficial for individuals with poor adherence to
CPAP.
## Availability of data and materials
The datasets used and analyzed in this study are available from Hongliang Yi,
the corresponding author, on reasonable request.
## Abbreviations
AASM:
American Academy of Sleep Medicine
AHI:
Apnea–hypopnea index
APOC:
Amsterdam Positional Obstructive Sleep Apnea Classification
ArTH:
Respiratory arousal threshold
BMI:
Body mass index
BSP:
Best sleeping position
CC:
Cartwright Classification
CI:
Confidence interval
CPAP:
Continuous positive airway pressure
CT90:
Cumulative time of oxygen saturation < 90%
CVD:
Cardiovascular disease
EDS:
Excessive daytime sleepiness
ESS:
Epworth Sleepiness Scale
HC:
Hip circumference
HOMA-IR:
Homeostasis model assessment of insulin resistance
LSaO2:
Lowest oxygen saturation
MAI:
Microarousal index
MS:
Metabolic syndrome
NC:
Neck circumference
NPOSA:
Non-positional obstructive sleep apnea
NREM:
Non-rapid eye movement sleep
ODI:
Oxygen desaturation index
OR:
Odds ratio
OSA:
Obstructive sleep apnea
POSA:
Positional obstructive sleep apnea
PSG:
Polysomnography
REM:
Rapid eye movement sleep
SaO2:
Oxygen saturation
si-POSA:
Supine-isolated positional obstructive sleep apnea
sp-POSA:
Supine-predominant positional obstructive sleep apnea
SWS:
Slow wave sleep
TST:
Total sleep time
WC:
Waist circumference
WSP:
Worst sleeping position
## References
1. Benjafield AV, Ayas NT, Eastwood PR, Heinzer R, Ip MSM, Morrell MJ, et al. Estimation of the global prevalence and burden of obstructive sleep apnoea: a literature-based analysis. Lancet Respir Med. 2019;7(8):687–98. [ https://doi.org/10.1016/s2213-2600(19)30198-5 ](https://doi.org/10.1016/s2213-2600\(19\)30198-5) .
[ Article ](https://doi.org/10.1016%2Fs2213-2600%2819%2930198-5) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=31300334)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7007763) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Estimation%20of%20the%20global%20prevalence%20and%20burden%20of%20obstructive%20sleep%20apnoea%3A%20a%20literature-
based%20analysis&journal=Lancet%20Respir%20Med&doi=10.1016%2Fs2213-2600%2819%2930198-5&volume=7&issue=8&pages=687-698&publication_year=2019&author=Benjafield%2CAV&author=Ayas%2CNT&author=Eastwood%2CPR&author=Heinzer%2CR&author=Ip%2CMSM&author=Morrell%2CMJ)
2. Senaratna CV, Perret JL, Lodge CJ, Lowe AJ, Campbell BE, Matheson MC, et al. Prevalence of obstructive sleep apnea in the general population: a systematic review. Sleep Med Rev. 2017;34:70–81. [ https://doi.org/10.1016/j.smrv.2016.07.002 ](https://doi.org/10.1016/j.smrv.2016.07.002) .
[ Article ](https://doi.org/10.1016%2Fj.smrv.2016.07.002) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27568340)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Prevalence%20of%20obstructive%20sleep%20apnea%20in%20the%20general%20population%3A%20a%20systematic%20review&journal=Sleep%20Med%20Rev&doi=10.1016%2Fj.smrv.2016.07.002&volume=34&pages=70-81&publication_year=2017&author=Senaratna%2CCV&author=Perret%2CJL&author=Lodge%2CCJ&author=Lowe%2CAJ&author=Campbell%2CBE&author=Matheson%2CMC)
3. Pedrosa RP, Drager LF, Gonzaga CC, Sousa MG, de Paula LK, Amaro AC, et al. Obstructive sleep apnea: the most common secondary cause of hypertension associated with resistant hypertension. Hypertension. 2011;58(5):811–7. [ https://doi.org/10.1161/hypertensionaha.111.179788 ](https://doi.org/10.1161/hypertensionaha.111.179788) .
[ Article ](https://doi.org/10.1161%2Fhypertensionaha.111.179788) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BC3MXhtlChsb%2FL) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21968750)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Obstructive%20sleep%20apnea%3A%20the%20most%20common%20secondary%20cause%20of%20hypertension%20associated%20with%20resistant%20hypertension&journal=Hypertension&doi=10.1161%2Fhypertensionaha.111.179788&volume=58&issue=5&pages=811-817&publication_year=2011&author=Pedrosa%2CRP&author=Drager%2CLF&author=Gonzaga%2CCC&author=Sousa%2CMG&author=Paula%2CLK&author=Amaro%2CAC)
4. Peker Y, Carlson J, Hedner J. Increased incidence of coronary artery disease in sleep apnoea: a long-term follow-up. Eur Respir J. 2006;28(3):596–602. [ https://doi.org/10.1183/09031936.06.00107805 ](https://doi.org/10.1183/09031936.06.00107805) .
[ Article ](https://doi.org/10.1183%2F09031936.06.00107805) [ CAS
](/articles/cas-redirect/1:STN:280:DC%2BD28rit1WrtQ%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=16641120)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Increased%20incidence%20of%20coronary%20artery%20disease%20in%20sleep%20apnoea%3A%20a%20long-
term%20follow-
up&journal=Eur%20Respir%20J&doi=10.1183%2F09031936.06.00107805&volume=28&issue=3&pages=596-602&publication_year=2006&author=Peker%2CY&author=Carlson%2CJ&author=Hedner%2CJ)
5. Gottlieb DJ, Punjabi NM. Diagnosis and management of obstructive sleep apnea: a review. JAMA. 2020;323(14):1389–400. [ https://doi.org/10.1001/jama.2020.3514 ](https://doi.org/10.1001/jama.2020.3514) .
[ Article ](https://doi.org/10.1001%2Fjama.2020.3514) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32286648)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Diagnosis%20and%20management%20of%20obstructive%20sleep%20apnea%3A%20a%20review&journal=JAMA&doi=10.1001%2Fjama.2020.3514&volume=323&issue=14&pages=1389-1400&publication_year=2020&author=Gottlieb%2CDJ&author=Punjabi%2CNM)
6. Cartwright RD. Effect of sleep position on sleep apnea severity. Sleep. 1984;7(2):110–4. [ https://doi.org/10.1093/sleep/7.2.110 ](https://doi.org/10.1093/sleep/7.2.110) .
[ Article ](https://doi.org/10.1093%2Fsleep%2F7.2.110) [ CAS ](/articles/cas-
redirect/1:STN:280:DyaL2c3kvFChug%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=6740055)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Effect%20of%20sleep%20position%20on%20sleep%20apnea%20severity&journal=Sleep&doi=10.1093%2Fsleep%2F7.2.110&volume=7&issue=2&pages=110-114&publication_year=1984&author=Cartwright%2CRD)
7. Frank MH, Ravesloot MJ, van Maanen JP, Verhagen E, de Lange J, de Vries N. Positional OSA part 1: towards a clinical classification system for position-dependent obstructive sleep apnoea. Sleep Breath. 2015;19(2):473–80. [ https://doi.org/10.1007/s11325-014-1022-9 ](https://doi.org/10.1007/s11325-014-1022-9) .
[ Article ](https://link.springer.com/doi/10.1007/s11325-014-1022-9) [ CAS
](/articles/cas-redirect/1:STN:280:DC%2BC2cfjs12lsg%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=24943728)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Positional%20OSA%20part%201%3A%20towards%20a%20clinical%20classification%20system%20for%20position-
dependent%20obstructive%20sleep%20apnoea&journal=Sleep%20Breath&doi=10.1007%2Fs11325-014-1022-9&volume=19&issue=2&pages=473-480&publication_year=2015&author=Frank%2CMH&author=Ravesloot%2CMJ&author=Maanen%2CJP&author=Verhagen%2CE&author=Lange%2CJ&author=Vries%2CN)
8. Mador MJ, Kufel TJ, Magalang UJ, Rajesh SK, Watwe V, Grant BJ. Prevalence of positional sleep apnea in patients undergoing polysomnography. Chest. 2005;128(4):2130–7. [ https://doi.org/10.1378/chest.128.4.2130 ](https://doi.org/10.1378/chest.128.4.2130) .
[ Article ](https://doi.org/10.1378%2Fchest.128.4.2130) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=16236865)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Prevalence%20of%20positional%20sleep%20apnea%20in%20patients%20undergoing%20polysomnography&journal=Chest&doi=10.1378%2Fchest.128.4.2130&volume=128&issue=4&pages=2130-2137&publication_year=2005&author=Mador%2CMJ&author=Kufel%2CTJ&author=Magalang%2CUJ&author=Rajesh%2CSK&author=Watwe%2CV&author=Grant%2CBJ)
9. Kim KT, Cho YW, Kim DE, Hwang SH, Song ML, Motamedi GK. Two subtypes of positional obstructive sleep apnea: supine-predominant and supine-isolated. Clin Neurophysiol. 2016;127(1):565–70. [ https://doi.org/10.1016/j.clinph.2015.06.009 ](https://doi.org/10.1016/j.clinph.2015.06.009) .
[ Article ](https://doi.org/10.1016%2Fj.clinph.2015.06.009) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=26116298)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Two%20subtypes%20of%20positional%20obstructive%20sleep%20apnea%3A%20supine-
predominant%20and%20supine-
isolated&journal=Clin%20Neurophysiol&doi=10.1016%2Fj.clinph.2015.06.009&volume=127&issue=1&pages=565-570&publication_year=2016&author=Kim%2CKT&author=Cho%2CYW&author=Kim%2CDE&author=Hwang%2CSH&author=Song%2CML&author=Motamedi%2CGK)
10. Lee SA, Paek JH, Chung YS, Kim WS. Clinical features in patients with positional obstructive sleep apnea according to its subtypes. Sleep Breath. 2017;21(1):109–17. [ https://doi.org/10.1007/s11325-016-1379-z ](https://doi.org/10.1007/s11325-016-1379-z) .
[ Article ](https://link.springer.com/doi/10.1007/s11325-016-1379-z) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27406180)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Clinical%20features%20in%20patients%20with%20positional%20obstructive%20sleep%20apnea%20according%20to%20its%20subtypes&journal=Sleep%20Breath&doi=10.1007%2Fs11325-016-1379-z&volume=21&issue=1&pages=109-117&publication_year=2017&author=Lee%2CSA&author=Paek%2CJH&author=Chung%2CYS&author=Kim%2CWS)
11. Oulhaj A, Al Dhaheri S, Su BB, Al-Houqani M. Discriminating between positional and non-positional obstructive sleep apnea using some clinical characteristics. Sleep Breath. 2017;21(4):877–84. [ https://doi.org/10.1007/s11325-017-1499-0 ](https://doi.org/10.1007/s11325-017-1499-0) .
[ Article ](https://link.springer.com/doi/10.1007/s11325-017-1499-0) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=28425082)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Discriminating%20between%20positional%20and%20non-
positional%20obstructive%20sleep%20apnea%20using%20some%20clinical%20characteristics&journal=Sleep%20Breath&doi=10.1007%2Fs11325-017-1499-0&volume=21&issue=4&pages=877-884&publication_year=2017&author=Oulhaj%2CA&author=Al%20Dhaheri%2CS&author=Su%2CBB&author=Al-
Houqani%2CM)
12. Koh WP, Mok Y, Poh Y, Kam JW, Wong HS. Prevalence of positional obstructive sleep apnoea (OSA) among patients with OSA in a tertiary healthcare institution in Singapore. Singapore Med J. 2020;61(12):665–6. [ https://doi.org/10.11622/smedj.2020153 ](https://doi.org/10.11622/smedj.2020153) .
[ Article ](https://doi.org/10.11622%2Fsmedj.2020153) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=33415342)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7930302) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Prevalence%20of%20positional%20obstructive%20sleep%20apnoea%20%28OSA%29%20among%20patients%20with%20OSA%20in%20a%20tertiary%20healthcare%20institution%20in%20Singapore&journal=Singapore%20Med%20J&doi=10.11622%2Fsmedj.2020153&volume=61&issue=12&pages=665-666&publication_year=2020&author=Koh%2CWP&author=Mok%2CY&author=Poh%2CY&author=Kam%2CJW&author=Wong%2CHS)
13. Mo JH, Lee CH, Rhee CS, Yoon IY, Kim JW. Positional dependency in Asian patients with obstructive sleep apnea and its implication for hypertension. Arch Otolaryngol Head Neck Surg. 2011;137(8):786–90. [ https://doi.org/10.1001/archoto.2011.122 ](https://doi.org/10.1001/archoto.2011.122) .
[ Article ](https://doi.org/10.1001%2Farchoto.2011.122) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21844412)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Positional%20dependency%20in%20Asian%20patients%20with%20obstructive%20sleep%20apnea%20and%20its%20implication%20for%20hypertension&journal=Arch%20Otolaryngol%20Head%20Neck%20Surg&doi=10.1001%2Farchoto.2011.122&volume=137&issue=8&pages=786-790&publication_year=2011&author=Mo%2CJH&author=Lee%2CCH&author=Rhee%2CCS&author=Yoon%2CIY&author=Kim%2CJW)
14. Wang X, Luo J, Huang R, Yi X. Preliminary study on clinical characteristics of Chinese patients with positional obstructive sleep apnea. Sleep Breath. 2021. [ https://doi.org/10.1007/s11325-021-02346-8 ](https://doi.org/10.1007/s11325-021-02346-8) .
[ Article ](https://link.springer.com/doi/10.1007/s11325-021-02346-8) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=34845629)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8084412) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Preliminary%20study%20on%20clinical%20characteristics%20of%20Chinese%20patients%20with%20positional%20obstructive%20sleep%20apnea&journal=Sleep%20Breath&doi=10.1007%2Fs11325-021-02346-8&publication_year=2021&author=Wang%2CX&author=Luo%2CJ&author=Huang%2CR&author=Yi%2CX)
15. Garg H, Er XY, Howarth T, Heraganahally SS. Positional sleep apnea among regional and remote australian population and simulated positional treatment effects. Nat Sci Sleep. 2020;12:1123–35. [ https://doi.org/10.2147/nss.S286403 ](https://doi.org/10.2147/nss.S286403) .
[ Article ](https://doi.org/10.2147%2Fnss.S286403) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=33304112)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7723233) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Positional%20sleep%20apnea%20among%20regional%20and%20remote%20australian%20population%20and%20simulated%20positional%20treatment%20effects&journal=Nat%20Sci%20Sleep&doi=10.2147%2Fnss.S286403&volume=12&pages=1123-1135&publication_year=2020&author=Garg%2CH&author=Er%2CXY&author=Howarth%2CT&author=Heraganahally%2CSS)
16. Sabil A, Blanchard M, Trzepizur W, Goupil F, Meslier N, Paris A, et al. Positional obstructive sleep apnea within a large multicenter French cohort: prevalence, characteristics, and treatment outcomes. J Clin Sleep Med. 2020;16(12):2037–46. [ https://doi.org/10.5664/jcsm.8752 ](https://doi.org/10.5664/jcsm.8752) .
[ Article ](https://doi.org/10.5664%2Fjcsm.8752) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32804071)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7848932) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Positional%20obstructive%20sleep%20apnea%20within%20a%20large%20multicenter%20French%20cohort%3A%20prevalence%2C%20characteristics%2C%20and%20treatment%20outcomes&journal=J%20Clin%20Sleep%20Med&doi=10.5664%2Fjcsm.8752&volume=16&issue=12&pages=2037-2046&publication_year=2020&author=Sabil%2CA&author=Blanchard%2CM&author=Trzepizur%2CW&author=Goupil%2CF&author=Meslier%2CN&author=Paris%2CA)
17. Oksenberg A, Silverberg DS, Arons E, Radwan H. Positional vs nonpositional obstructive sleep apnea patients: anthropomorphic, nocturnal polysomnographic, and multiple sleep latency test data. Chest. 1997;112(3):629–39. [ https://doi.org/10.1378/chest.112.3.629 ](https://doi.org/10.1378/chest.112.3.629) .
[ Article ](https://doi.org/10.1378%2Fchest.112.3.629) [ CAS ](/articles/cas-
redirect/1:STN:280:DyaK2svlvFygtg%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=9315794)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Positional%20vs%20nonpositional%20obstructive%20sleep%20apnea%20patients%3A%20anthropomorphic%2C%20nocturnal%20polysomnographic%2C%20and%20multiple%20sleep%20latency%20test%20data&journal=Chest&doi=10.1378%2Fchest.112.3.629&volume=112&issue=3&pages=629-639&publication_year=1997&author=Oksenberg%2CA&author=Silverberg%2CDS&author=Arons%2CE&author=Radwan%2CH)
18. Joosten SA, Hamza K, Sands S, Turton A, Berger P, Hamilton G. Phenotypes of patients with mild to moderate obstructive sleep apnoea as confirmed by cluster analysis. Respirology. 2012;17(1):99–107. [ https://doi.org/10.1111/j.1440-1843.2011.02037.x ](https://doi.org/10.1111/j.1440-1843.2011.02037.x) .
[ Article ](https://doi.org/10.1111%2Fj.1440-1843.2011.02037.x) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21848707)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Phenotypes%20of%20patients%20with%20mild%20to%20moderate%20obstructive%20sleep%20apnoea%20as%20confirmed%20by%20cluster%20analysis&journal=Respirology&doi=10.1111%2Fj.1440-1843.2011.02037.x&volume=17&issue=1&pages=99-107&publication_year=2012&author=Joosten%2CSA&author=Hamza%2CK&author=Sands%2CS&author=Turton%2CA&author=Berger%2CP&author=Hamilton%2CG)
19. Teerapraipruk B, Chirakalwasan N, Simon R, Hirunwiwatkul P, Jaimchariyatam N, Desudchit T, et al. Clinical and polysomnographic data of positional sleep apnea and its predictors. Sleep Breath. 2012;16(4):1167–72. [ https://doi.org/10.1007/s11325-011-0627-5 ](https://doi.org/10.1007/s11325-011-0627-5) .
[ Article ](https://link.springer.com/doi/10.1007/s11325-011-0627-5) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=22134851)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Clinical%20and%20polysomnographic%20data%20of%20positional%20sleep%20apnea%20and%20its%20predictors&journal=Sleep%20Breath&doi=10.1007%2Fs11325-011-0627-5&volume=16&issue=4&pages=1167-1172&publication_year=2012&author=Teerapraipruk%2CB&author=Chirakalwasan%2CN&author=Simon%2CR&author=Hirunwiwatkul%2CP&author=Jaimchariyatam%2CN&author=Desudchit%2CT)
20. Heinzer R, Petitpierre NJ, Marti-Soler H, Haba-Rubio J. Prevalence and characteristics of positional sleep apnea in the HypnoLaus population-based cohort. Sleep Med. 2018;48:157–62. [ https://doi.org/10.1016/j.sleep.2018.02.011 ](https://doi.org/10.1016/j.sleep.2018.02.011) .
[ Article ](https://doi.org/10.1016%2Fj.sleep.2018.02.011) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=29957486)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Prevalence%20and%20characteristics%20of%20positional%20sleep%20apnea%20in%20the%20HypnoLaus%20population-
based%20cohort&journal=Sleep%20Med&doi=10.1016%2Fj.sleep.2018.02.011&volume=48&pages=157-162&publication_year=2018&author=Heinzer%2CR&author=Petitpierre%2CNJ&author=Marti-
Soler%2CH&author=Haba-Rubio%2CJ)
21. Selvadurai S, Voutsas G, Massicotte C, Kassner A, Katz SL, Propst EJ, et al. Positional obstructive sleep apnea in an obese pediatric population. J Clin Sleep Med. 2020;16(8):1295–301. [ https://doi.org/10.5664/jcsm.8496 ](https://doi.org/10.5664/jcsm.8496) .
[ Article ](https://doi.org/10.5664%2Fjcsm.8496) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32807295)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7446091) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Positional%20obstructive%20sleep%20apnea%20in%20an%20obese%20pediatric%20population&journal=J%20Clin%20Sleep%20Med&doi=10.5664%2Fjcsm.8496&volume=16&issue=8&pages=1295-1301&publication_year=2020&author=Selvadurai%2CS&author=Voutsas%2CG&author=Massicotte%2CC&author=Kassner%2CA&author=Katz%2CSL&author=Propst%2CEJ)
22. Iannella G, Magliulo G, Lo Iacono CAM, Bianchi G, Polimeni A, Greco A, et al. Positional obstructive sleep apnea syndrome in elderly patients. Int J Environ Res Public Health. 2020. [ https://doi.org/10.3390/ijerph17031120 ](https://doi.org/10.3390/ijerph17031120) .
[ Article ](https://doi.org/10.3390%2Fijerph17031120) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32718065)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7432019) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Positional%20obstructive%20sleep%20apnea%20syndrome%20in%20elderly%20patients&journal=Int%20J%20Environ%20Res%20Public%20Health&doi=10.3390%2Fijerph17031120&publication_year=2020&author=Iannella%2CG&author=Magliulo%2CG&author=Lo%20Iacono%2CCAM&author=Bianchi%2CG&author=Polimeni%2CA&author=Greco%2CA)
23. O’Driscoll DM, Landry SA, Pham J, Young A, Sands SA, Hamilton GS, et al. The physiological phenotype of obstructive sleep apnea differs between Caucasian and Chinese patients. Sleep. 2019. [ https://doi.org/10.1093/sleep/zsz186 ](https://doi.org/10.1093/sleep/zsz186) .
[ Article ](https://doi.org/10.1093%2Fsleep%2Fzsz186) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=31418028)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20physiological%20phenotype%20of%20obstructive%20sleep%20apnea%20differs%20between%20Caucasian%20and%20Chinese%20patients&journal=Sleep&doi=10.1093%2Fsleep%2Fzsz186&publication_year=2019&author=O%27Driscoll%2CDM&author=Landry%2CSA&author=Pham%2CJ&author=Young%2CA&author=Sands%2CSA&author=Hamilton%2CGS)
24. Joosten SA, O’Driscoll DM, Berger PJ, Hamilton GS. Supine position related obstructive sleep apnea in adults: pathogenesis and treatment. Sleep Med Rev. 2014;18(1):7–17. [ https://doi.org/10.1016/j.smrv.2013.01.005 ](https://doi.org/10.1016/j.smrv.2013.01.005) .
[ Article ](https://doi.org/10.1016%2Fj.smrv.2013.01.005) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=23669094)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Supine%20position%20related%20obstructive%20sleep%20apnea%20in%20adults%3A%20pathogenesis%20and%20treatment&journal=Sleep%20Med%20Rev&doi=10.1016%2Fj.smrv.2013.01.005&volume=18&issue=1&pages=7-17&publication_year=2014&author=Joosten%2CSA&author=O%27Driscoll%2CDM&author=Berger%2CPJ&author=Hamilton%2CGS)
25. Taranto-Montemurro L, Messineo L, Wellman A. Targeting endotypic traits with medications for the pharmacological treatment of obstructive sleep apnea. A review of the current literature. J Clin Med. 2019. [ https://doi.org/10.3390/jcm8111846 ](https://doi.org/10.3390/jcm8111846) .
[ Article ](https://doi.org/10.3390%2Fjcm8111846) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=31684047)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6912255) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Targeting%20endotypic%20traits%20with%20medications%20for%20the%20pharmacological%20treatment%20of%20obstructive%20sleep%20apnea.%20A%20review%20of%20the%20current%20literature&journal=J%20Clin%20Med&doi=10.3390%2Fjcm8111846&publication_year=2019&author=Taranto-
Montemurro%2CL&author=Messineo%2CL&author=Wellman%2CA)
26. Zinchuk AV, Gentry MJ, Concato J, Yaggi HK. Phenotypes in obstructive sleep apnea: a definition, examples and evolution of approaches. Sleep Med Rev. 2017;35:113–23. [ https://doi.org/10.1016/j.smrv.2016.10.002 ](https://doi.org/10.1016/j.smrv.2016.10.002) .
[ Article ](https://doi.org/10.1016%2Fj.smrv.2016.10.002) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27815038)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Phenotypes%20in%20obstructive%20sleep%20apnea%3A%20a%20definition%2C%20examples%20and%20evolution%20of%20approaches&journal=Sleep%20Med%20Rev&doi=10.1016%2Fj.smrv.2016.10.002&volume=35&pages=113-123&publication_year=2017&author=Zinchuk%2CAV&author=Gentry%2CMJ&author=Concato%2CJ&author=Yaggi%2CHK)
27. Eckert DJ, White DP, Jordan AS, Malhotra A, Wellman A. Defining phenotypic causes of obstructive sleep apnea. Identification of novel therapeutic targets. Am J Respir Crit Care Med. 2013;188(8):996–1004. [ https://doi.org/10.1164/rccm.201303-0448OC ](https://doi.org/10.1164/rccm.201303-0448OC) .
[ Article ](https://doi.org/10.1164%2Frccm.201303-0448OC) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=23721582)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3826282) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Defining%20phenotypic%20causes%20of%20obstructive%20sleep%20apnea.%20Identification%20of%20novel%20therapeutic%20targets&journal=Am%20J%20Respir%20Crit%20Care%20Med&doi=10.1164%2Frccm.201303-0448OC&volume=188&issue=8&pages=996-1004&publication_year=2013&author=Eckert%2CDJ&author=White%2CDP&author=Jordan%2CAS&author=Malhotra%2CA&author=Wellman%2CA)
28. Younes M. Role of arousals in the pathogenesis of obstructive sleep apnea. Am J Respir Crit Care Med. 2004;169(5):623–33. [ https://doi.org/10.1164/rccm.200307-1023OC ](https://doi.org/10.1164/rccm.200307-1023OC) .
[ Article ](https://doi.org/10.1164%2Frccm.200307-1023OC) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=14684560)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Role%20of%20arousals%20in%20the%20pathogenesis%20of%20obstructive%20sleep%20apnea&journal=Am%20J%20Respir%20Crit%20Care%20Med&doi=10.1164%2Frccm.200307-1023OC&volume=169&issue=5&pages=623-633&publication_year=2004&author=Younes%2CM)
29. Zinchuk AV, Chu JH, Liang J, Celik Y, de Op Beeck S, Redeker NS, et al. Physiological traits and adherence to sleep apnea therapy in individuals with coronary artery disease. Am J Respir Crit Care Med. 2021;204(6):703–12. [ https://doi.org/10.1164/rccm.202101-0055OC ](https://doi.org/10.1164/rccm.202101-0055OC) .
[ Article ](https://doi.org/10.1164%2Frccm.202101-0055OC) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=34156917)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Physiological%20traits%20and%20adherence%20to%20sleep%20apnea%20therapy%20in%20individuals%20with%20coronary%20artery%20disease&journal=Am%20J%20Respir%20Crit%20Care%20Med&doi=10.1164%2Frccm.202101-0055OC&volume=204&issue=6&pages=703-712&publication_year=2021&author=Zinchuk%2CAV&author=Chu%2CJH&author=Liang%2CJ&author=Celik%2CY&author=Op%20Beeck%2CS&author=Redeker%2CNS)
30. Bonora E, Targher G, Alberiche M, Bonadonna RC, Saggiani F, Zenere MB, et al. Homeostasis model assessment closely mirrors the glucose clamp technique in the assessment of insulin sensitivity: studies in subjects with various degrees of glucose tolerance and insulin sensitivity. Diabetes Care. 2000;23(1):57–63. [ https://doi.org/10.2337/diacare.23.1.57 ](https://doi.org/10.2337/diacare.23.1.57) .
[ Article ](https://doi.org/10.2337%2Fdiacare.23.1.57) [ CAS ](/articles/cas-
redirect/1:STN:280:DC%2BD3czpsVyisA%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=10857969)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Homeostasis%20model%20assessment%20closely%20mirrors%20the%20glucose%20clamp%20technique%20in%20the%20assessment%20of%20insulin%20sensitivity%3A%20studies%20in%20subjects%20with%20various%20degrees%20of%20glucose%20tolerance%20and%20insulin%20sensitivity&journal=Diabetes%20Care&doi=10.2337%2Fdiacare.23.1.57&volume=23&issue=1&pages=57-63&publication_year=2000&author=Bonora%2CE&author=Targher%2CG&author=Alberiche%2CM&author=Bonadonna%2CRC&author=Saggiani%2CF&author=Zenere%2CMB)
31. Catapano AL, Graham I, De Backer G, Wiklund O, Chapman MJ, Drexel H, et al. 2016 ESC/EAS guidelines for the management of dyslipidaemias. Eur Heart J. 2016;37(39):2999–3058. [ https://doi.org/10.1093/eurheartj/ehw272 ](https://doi.org/10.1093/eurheartj/ehw272) .
[ Article ](https://doi.org/10.1093%2Feurheartj%2Fehw272) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27567407)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=2016%20ESC%2FEAS%20guidelines%20for%20the%20management%20of%20dyslipidaemias&journal=Eur%20Heart%20J&doi=10.1093%2Feurheartj%2Fehw272&volume=37&issue=39&pages=2999-3058&publication_year=2016&author=Catapano%2CAL&author=Graham%2CI&author=Backer%2CG&author=Wiklund%2CO&author=Chapman%2CMJ&author=Drexel%2CH)
32. Alberti KG, Zimmet P, Shaw J. The metabolic syndrome–a new worldwide definition. Lancet. 2005;366(9491):1059–62. [ https://doi.org/10.1016/s0140-6736(05)67402-8 ](https://doi.org/10.1016/s0140-6736\(05\)67402-8) .
[ Article ](https://doi.org/10.1016%2Fs0140-6736%2805%2967402-8) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=16182882)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20metabolic%20syndrome%E2%80%93a%20new%20worldwide%20definition&journal=Lancet&doi=10.1016%2Fs0140-6736%2805%2967402-8&volume=366&issue=9491&pages=1059-1062&publication_year=2005&author=Alberti%2CKG&author=Zimmet%2CP&author=Shaw%2CJ)
33. Johns MW. A new method for measuring daytime sleepiness: the Epworth sleepiness scale. Sleep. 1991;14(6):540–5. [ https://doi.org/10.1093/sleep/14.6.540 ](https://doi.org/10.1093/sleep/14.6.540) .
[ Article ](https://doi.org/10.1093%2Fsleep%2F14.6.540) [ CAS ](/articles/cas-
redirect/1:STN:280:DyaK387ovVSksw%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=1798888)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=A%20new%20method%20for%20measuring%20daytime%20sleepiness%3A%20the%20Epworth%20sleepiness%20scale&journal=Sleep&doi=10.1093%2Fsleep%2F14.6.540&volume=14&issue=6&pages=540-545&publication_year=1991&author=Johns%2CMW)
34. Hidalgo Armas L, Ingles S, Vaca R, Cordero-Guevara J, Duran Carro J, Ullate J, et al. New forehead device in positional obstructive sleep apnoea: a randomised clinical trial. Thorax. 2021;76(9):930–8. [ https://doi.org/10.1136/thoraxjnl-2020-216167 ](https://doi.org/10.1136/thoraxjnl-2020-216167) .
[ Article ](https://doi.org/10.1136%2Fthoraxjnl-2020-216167) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=33888576)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=New%20forehead%20device%20in%20positional%20obstructive%20sleep%20apnoea%3A%20a%20randomised%20clinical%20trial&journal=Thorax&doi=10.1136%2Fthoraxjnl-2020-216167&volume=76&issue=9&pages=930-938&publication_year=2021&author=Hidalgo%20Armas%2CL&author=Ingles%2CS&author=Vaca%2CR&author=Cordero-
Guevara%2CJ&author=Duran%20Carro%2CJ&author=Ullate%2CJ)
35. Berry RB, Budhiraja R, Gottlieb DJ, Gozal D, Iber C, Kapur VK, et al. Rules for scoring respiratory events in sleep: update of the 2007 AASM manual for the scoring of sleep and associated events. Deliberations of the sleep apnea definitions task force of the American Academy of Sleep Medicine. J Clin Sleep Med. 2012;8(5):597–619. [ https://doi.org/10.5664/jcsm.2172 ](https://doi.org/10.5664/jcsm.2172) .
[ Article ](https://doi.org/10.5664%2Fjcsm.2172) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=23066376)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3459210) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Rules%20for%20scoring%20respiratory%20events%20in%20sleep%3A%20update%20of%20the%202007%20AASM%20manual%20for%20the%20scoring%20of%20sleep%20and%20associated%20events.%20Deliberations%20of%20the%20sleep%20apnea%20definitions%20task%20force%20of%20the%20American%20Academy%20of%20Sleep%20Medicine&journal=J%20Clin%20Sleep%20Med&doi=10.5664%2Fjcsm.2172&volume=8&issue=5&pages=597-619&publication_year=2012&author=Berry%2CRB&author=Budhiraja%2CR&author=Gottlieb%2CDJ&author=Gozal%2CD&author=Iber%2CC&author=Kapur%2CVK)
36. Guan J, Yi H, Zou J, Meng L, Tang X, Zhu H, et al. Distinct severity stages of obstructive sleep apnoea are correlated with unique dyslipidaemia: large-scale observational study. Thorax. 2016;71(4):347–55. [ https://doi.org/10.1136/thoraxjnl-2015-207403 ](https://doi.org/10.1136/thoraxjnl-2015-207403) .
[ Article ](https://doi.org/10.1136%2Fthoraxjnl-2015-207403) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=26883674)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Distinct%20severity%20stages%20of%20obstructive%20sleep%20apnoea%20are%20correlated%20with%20unique%20dyslipidaemia%3A%20large-
scale%20observational%20study&journal=Thorax&doi=10.1136%2Fthoraxjnl-2015-207403&volume=71&issue=4&pages=347-355&publication_year=2016&author=Guan%2CJ&author=Yi%2CH&author=Zou%2CJ&author=Meng%2CL&author=Tang%2CX&author=Zhu%2CH)
37. Ravesloot MJ, Frank MH, van Maanen JP, Verhagen EA, de Lange J, de Vries N. Positional OSA part 2: retrospective cohort analysis with a new classification system (APOC). Sleep Breath. 2016;20(2):881–8. [ https://doi.org/10.1007/s11325-015-1206-y ](https://doi.org/10.1007/s11325-015-1206-y) .
[ Article ](https://link.springer.com/doi/10.1007/s11325-015-1206-y) [ CAS
](/articles/cas-redirect/1:STN:280:DC%2BC2MbksVCktg%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=26084413)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Positional%20OSA%20part%202%3A%20retrospective%20cohort%20analysis%20with%20a%20new%20classification%20system%20%28APOC%29&journal=Sleep%20Breath&doi=10.1007%2Fs11325-015-1206-y&volume=20&issue=2&pages=881-888&publication_year=2016&author=Ravesloot%2CMJ&author=Frank%2CMH&author=Maanen%2CJP&author=Verhagen%2CEA&author=Lange%2CJ&author=Vries%2CN)
38. Edwards BA, Eckert DJ, McSharry DG, Sands SA, Desai A, Kehlmann G, et al. Clinical predictors of the respiratory arousal threshold in patients with obstructive sleep apnea. Am J Respir Crit Care Med. 2014;190(11):1293–300. [ https://doi.org/10.1164/rccm.201404-0718OC ](https://doi.org/10.1164/rccm.201404-0718OC) .
[ Article ](https://doi.org/10.1164%2Frccm.201404-0718OC) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25321848)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4315811) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Clinical%20predictors%20of%20the%20respiratory%20arousal%20threshold%20in%20patients%20with%20obstructive%20sleep%20apnea&journal=Am%20J%20Respir%20Crit%20Care%20Med&doi=10.1164%2Frccm.201404-0718OC&volume=190&issue=11&pages=1293-1300&publication_year=2014&author=Edwards%2CBA&author=Eckert%2CDJ&author=McSharry%2CDG&author=Sands%2CSA&author=Desai%2CA&author=Kehlmann%2CG)
39. Schmickl CN, Li Y, Orr JE, Jen R, Sands SA, Edwards BA, et al. Effect of venlafaxine on apnea-hypopnea index in patients with sleep apnea: a randomized. Double-Blind Crossover. Study Chest. 2020;158(2):765–75. [ https://doi.org/10.1016/j.chest.2020.02.074 ](https://doi.org/10.1016/j.chest.2020.02.074) .
[ Article ](https://doi.org/10.1016%2Fj.chest.2020.02.074) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BB3cXhtlWnsLvL) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32278781)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Effect%20of%20venlafaxine%20on%20apnea-
hypopnea%20index%20in%20patients%20with%20sleep%20apnea%3A%20a%20randomized.%20Double-
Blind%20Crossover&journal=Study%20Chest&doi=10.1016%2Fj.chest.2020.02.074&volume=158&issue=2&pages=765-775&publication_year=2020&author=Schmickl%2CCN&author=Li%2CY&author=Orr%2CJE&author=Jen%2CR&author=Sands%2CSA&author=Edwards%2CBA)
40. Fu X, Li J, Wu JJ, Chen J, Huang JY, Mao CJ, et al. Reduced cortical arousability to nocturnal apneic episodes in patients with wake-up ischemic stroke. Sleep Med. 2020;66:252–8. [ https://doi.org/10.1016/j.sleep.2019.09.007 ](https://doi.org/10.1016/j.sleep.2019.09.007) .
[ Article ](https://doi.org/10.1016%2Fj.sleep.2019.09.007) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32008889)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Reduced%20cortical%20arousability%20to%20nocturnal%20apneic%20episodes%20in%20patients%20with%20wake-
up%20ischemic%20stroke&journal=Sleep%20Med&doi=10.1016%2Fj.sleep.2019.09.007&volume=66&pages=252-258&publication_year=2020&author=Fu%2CX&author=Li%2CJ&author=Wu%2CJJ&author=Chen%2CJ&author=Huang%2CJY&author=Mao%2CCJ)
41. Lee RWW, Sutherland K, Sands SA, Edwards BA, Chan TO, et al. Differences in respiratory arousal threshold in Caucasian and Chinese patients with obstructive sleep apnoea. Respirology. 2017;22(5):1015–21. [ https://doi.org/10.1111/resp.13022 ](https://doi.org/10.1111/resp.13022) .
[ Article ](https://doi.org/10.1111%2Fresp.13022) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=28303676)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Differences%20in%20respiratory%20arousal%20threshold%20in%20Caucasian%20and%20Chinese%20patients%20with%20obstructive%20sleep%20apnoea&journal=Respirology&doi=10.1111%2Fresp.13022&volume=22&issue=5&pages=1015-1021&publication_year=2017&author=Lee%2CRWW&author=Sutherland%2CK&author=Sands%2CSA&author=Edwards%2CBA&author=Chan%2CTO)
42. Lee RW, Vasudavan S, Hui DS, Prvan T, Petocz P, Darendeliler MA, et al. Differences in craniofacial structures and obesity in Caucasian and Chinese patients with obstructive sleep apnea. Sleep. 2010;33(8):1075–80. [ https://doi.org/10.1093/sleep/33.8.1075 ](https://doi.org/10.1093/sleep/33.8.1075) .
[ Article ](https://doi.org/10.1093%2Fsleep%2F33.8.1075) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=20815189)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2910536) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Differences%20in%20craniofacial%20structures%20and%20obesity%20in%20Caucasian%20and%20Chinese%20patients%20with%20obstructive%20sleep%20apnea&journal=Sleep&doi=10.1093%2Fsleep%2F33.8.1075&volume=33&issue=8&pages=1075-1080&publication_year=2010&author=Lee%2CRW&author=Vasudavan%2CS&author=Hui%2CDS&author=Prvan%2CT&author=Petocz%2CP&author=Darendeliler%2CMA)
43. Hui DSC, Ko FWS, Chu ASY, Fok JPC, Chan MCH, Li TST, et al. Cephalometric assessment of craniofacial morphology in Chinese patients with obstructive sleep apnoea. Respir Med. 2003;97(6):640–6. [ https://doi.org/10.1053/rmed.2003.1494 ](https://doi.org/10.1053/rmed.2003.1494) .
[ Article ](https://doi.org/10.1053%2Frmed.2003.1494) [ CAS ](/articles/cas-
redirect/1:STN:280:DC%2BD3s3os1KjsA%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=12814148)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Cephalometric%20assessment%20of%20craniofacial%20morphology%20in%20Chinese%20patients%20with%20obstructive%20sleep%20apnoea&journal=Respir%20Med&doi=10.1053%2Frmed.2003.1494&volume=97&issue=6&pages=640-646&publication_year=2003&author=Hui%2CDSC&author=Ko%2CFWS&author=Chu%2CASY&author=Fok%2CJPC&author=Chan%2CMCH&author=Li%2CTST)
44. Ong KC, Clerk AA. Comparison of the severity of sleep-disordered breathing in Asian and Caucasian patients seen at a sleep disorders center. Respir Med. 1998;92(6):843–8. [ https://doi.org/10.1016/s0954-6111(98)90386-9 ](https://doi.org/10.1016/s0954-6111\(98\)90386-9) .
[ Article ](https://doi.org/10.1016%2Fs0954-6111%2898%2990386-9) [ CAS
](/articles/cas-redirect/1:STN:280:DyaK1M%2Fmslemtg%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=9850368)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Comparison%20of%20the%20severity%20of%20sleep-
disordered%20breathing%20in%20Asian%20and%20Caucasian%20patients%20seen%20at%20a%20sleep%20disorders%20center&journal=Respir%20Med&doi=10.1016%2Fs0954-6111%2898%2990386-9&volume=92&issue=6&pages=843-848&publication_year=1998&author=Ong%2CKC&author=Clerk%2CAA)
45. Schorr F, Kayamori F, Hirata RP, Danzi-Soares NJ, Gebrim EM, Moriya HT, et al. Different craniofacial characteristics predict upper airway collapsibility in Japanese-Brazilian and white men. Chest. 2016;149(3):737–46. [ https://doi.org/10.1378/chest.15-0638 ](https://doi.org/10.1378/chest.15-0638) .
[ Article ](https://doi.org/10.1378%2Fchest.15-0638) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=26291487)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4944782) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Different%20craniofacial%20characteristics%20predict%20upper%20airway%20collapsibility%20in%20Japanese-
Brazilian%20and%20white%20men&journal=Chest&doi=10.1378%2Fchest.15-0638&volume=149&issue=3&pages=737-746&publication_year=2016&author=Schorr%2CF&author=Kayamori%2CF&author=Hirata%2CRP&author=Danzi-
Soares%2CNJ&author=Gebrim%2CEM&author=Moriya%2CHT)
46. Gleeson K, Zwillich CW, White DP. The influence of increasing ventilatory effort on arousal from sleep. Am Rev Respir Dis. 1990;142(2):295–300. [ https://doi.org/10.1164/ajrccm/142.2.295 ](https://doi.org/10.1164/ajrccm/142.2.295) .
[ Article ](https://doi.org/10.1164%2Fajrccm%2F142.2.295) [ CAS
](/articles/cas-redirect/1:STN:280:DyaK3czktlWgtg%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=2382892)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20influence%20of%20increasing%20ventilatory%20effort%20on%20arousal%20from%20sleep&journal=Am%20Rev%20Respir%20Dis&doi=10.1164%2Fajrccm%2F142.2.295&volume=142&issue=2&pages=295-300&publication_year=1990&author=Gleeson%2CK&author=Zwillich%2CCW&author=White%2CDP)
47. Younes M. Role of respiratory control mechanisms in the pathogenesis of obstructive sleep disorders. J Appl Physiol. 2008;105(5):1389–405. [ https://doi.org/10.1152/japplphysiol.90408.2008 ](https://doi.org/10.1152/japplphysiol.90408.2008) .
[ Article ](https://doi.org/10.1152%2Fjapplphysiol.90408.2008) [ CAS
](/articles/cas-redirect/1:CAS:528:DC%2BD1cXhsVOqsrbP) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=18787092)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Role%20of%20respiratory%20control%20mechanisms%20in%20the%20pathogenesis%20of%20obstructive%20sleep%20disorders&journal=J%20Appl%20Physiol&doi=10.1152%2Fjapplphysiol.90408.2008&volume=105&issue=5&pages=1389-1405&publication_year=2008&author=Younes%2CM)
48. Younes M, Ostrowski M, Thompson W, Leslie C, Shewchuk W. Chemical control stability in patients with obstructive sleep apnea. Am J Respir Crit Care Med. 2001;163(5):1181–90. [ https://doi.org/10.1164/ajrccm.163.5.2007013 ](https://doi.org/10.1164/ajrccm.163.5.2007013) .
[ Article ](https://doi.org/10.1164%2Fajrccm.163.5.2007013) [ CAS
](/articles/cas-redirect/1:STN:280:DC%2BD3MzisFGruw%3D%3D) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=11316657)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Chemical%20control%20stability%20in%20patients%20with%20obstructive%20sleep%20apnea&journal=Am%20J%20Respir%20Crit%20Care%20Med&doi=10.1164%2Fajrccm.163.5.2007013&volume=163&issue=5&pages=1181-1190&publication_year=2001&author=Younes%2CM&author=Ostrowski%2CM&author=Thompson%2CW&author=Leslie%2CC&author=Shewchuk%2CW)
49. Gray EL, McKenzie DK, Eckert DJ. Obstructive sleep apnea without obesity is common and difficult to treat: evidence for a distinct pathophysiological phenotype. J Clin Sleep Med. 2017;13(1):81–8. [ https://doi.org/10.5664/jcsm.6394 ](https://doi.org/10.5664/jcsm.6394) .
[ Article ](https://doi.org/10.5664%2Fjcsm.6394) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27655455)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5181619) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Obstructive%20sleep%20apnea%20without%20obesity%20is%20common%20and%20difficult%20to%20treat%3A%20evidence%20for%20a%20distinct%20pathophysiological%20phenotype&journal=J%20Clin%20Sleep%20Med&doi=10.5664%2Fjcsm.6394&volume=13&issue=1&pages=81-88&publication_year=2017&author=Gray%2CEL&author=McKenzie%2CDK&author=Eckert%2CDJ)
50. Eckert DJ, Owens RL, Kehlmann GB, Wellman A, Rahangdale S, Yim-Yeh S, et al. Eszopiclone increases the respiratory arousal threshold and lowers the apnoea/hypopnoea index in obstructive sleep apnoea patients with a low arousal threshold. Clin Sci (Lond). 2011;120(12):505–14. [ https://doi.org/10.1042/cs20100588 ](https://doi.org/10.1042/cs20100588) .
[ Article ](https://doi.org/10.1042%2Fcs20100588) [ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Eszopiclone%20increases%20the%20respiratory%20arousal%20threshold%20and%20lowers%20the%20apnoea%2Fhypopnoea%20index%20in%20obstructive%20sleep%20apnoea%20patients%20with%20a%20low%20arousal%20threshold&journal=Clin%20Sci%20%28Lond%29&doi=10.1042%2Fcs20100588&volume=120&issue=12&pages=505-514&publication_year=2011&author=Eckert%2CDJ&author=Owens%2CRL&author=Kehlmann%2CGB&author=Wellman%2CA&author=Rahangdale%2CS&author=Yim-
Yeh%2CS)
51. Zinchuk A, Edwards BA, Jeon S, Koo BB, Concato J, Sands S, et al. Prevalence, associated clinical features, and impact on continuous positive airway pressure use of a low respiratory arousal threshold among male United States veterans with obstructive sleep apnea. J Clin Sleep Med. 2018;14(5):809–17. [ https://doi.org/10.5664/jcsm.7112 ](https://doi.org/10.5664/jcsm.7112) .
[ Article ](https://doi.org/10.5664%2Fjcsm.7112) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=29734986)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5940432) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Prevalence%2C%20associated%20clinical%20features%2C%20and%20impact%20on%20continuous%20positive%20airway%20pressure%20use%20of%20a%20low%20respiratory%20arousal%20threshold%20among%20male%20United%20States%20veterans%20with%20obstructive%20sleep%20apnea&journal=J%20Clin%20Sleep%20Med&doi=10.5664%2Fjcsm.7112&volume=14&issue=5&pages=809-817&publication_year=2018&author=Zinchuk%2CA&author=Edwards%2CBA&author=Jeon%2CS&author=Koo%2CBB&author=Concato%2CJ&author=Sands%2CS)
52. Sutherland K, Lee RW, Cistulli PA. Obesity and craniofacial structure as risk factors for obstructive sleep apnoea: impact of ethnicity. Respirology. 2012;17(2):213–22. [ https://doi.org/10.1111/j.1440-1843.2011.02082.x ](https://doi.org/10.1111/j.1440-1843.2011.02082.x) .
[ Article ](https://doi.org/10.1111%2Fj.1440-1843.2011.02082.x) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=21992683)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Obesity%20and%20craniofacial%20structure%20as%20risk%20factors%20for%20obstructive%20sleep%20apnoea%3A%20impact%20of%20ethnicity&journal=Respirology&doi=10.1111%2Fj.1440-1843.2011.02082.x&volume=17&issue=2&pages=213-222&publication_year=2012&author=Sutherland%2CK&author=Lee%2CRW&author=Cistulli%2CPA)
53. Eckert DJ. Phenotypic approaches to obstructive sleep apnoea—new pathways for targeted therapy. Sleep Med Rev. 2018;37:45–59. [ https://doi.org/10.1016/j.smrv.2016.12.003 ](https://doi.org/10.1016/j.smrv.2016.12.003) .
[ Article ](https://doi.org/10.1016%2Fj.smrv.2016.12.003) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=28110857)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Phenotypic%20approaches%20to%20obstructive%20sleep%20apnoea%E2%80%94new%20pathways%20for%20targeted%20therapy&journal=Sleep%20Med%20Rev&doi=10.1016%2Fj.smrv.2016.12.003&volume=37&pages=45-59&publication_year=2018&author=Eckert%2CDJ)
54. McNicholas WT, Bonsignore MR, Lévy P, Ryan S. Mild obstructive sleep apnoea: clinical relevance and approaches to management. Lancet Respir Med. 2016;4(10):826–34. [ https://doi.org/10.1016/s2213-2600(16)30146-1 ](https://doi.org/10.1016/s2213-2600\(16\)30146-1) .
[ Article ](https://doi.org/10.1016%2Fs2213-2600%2816%2930146-1) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=27245915)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Mild%20obstructive%20sleep%20apnoea%3A%20clinical%20relevance%20and%20approaches%20to%20management&journal=Lancet%20Respir%20Med&doi=10.1016%2Fs2213-2600%2816%2930146-1&volume=4&issue=10&pages=826-834&publication_year=2016&author=McNicholas%2CWT&author=Bonsignore%2CMR&author=L%C3%A9vy%2CP&author=Ryan%2CS)
55. Joosten SA, Edwards BA, Wellman A, Turton A, Skuza EM, Berger PJ, et al. The effect of body position on physiological factors that contribute to obstructive sleep apnea. Sleep. 2015;38(9):1469–78. [ https://doi.org/10.5665/sleep.4992 ](https://doi.org/10.5665/sleep.4992) .
[ Article ](https://doi.org/10.5665%2Fsleep.4992) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=25761982)
[ PubMed Central ](http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4531415) [
Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20effect%20of%20body%20position%20on%20physiological%20factors%20that%20contribute%20to%20obstructive%20sleep%20apnea&journal=Sleep&doi=10.5665%2Fsleep.4992&volume=38&issue=9&pages=1469-1478&publication_year=2015&author=Joosten%2CSA&author=Edwards%2CBA&author=Wellman%2CA&author=Turton%2CA&author=Skuza%2CEM&author=Berger%2CPJ)
56. Messineo L, Eckert DJ, Lim R, Chiang A, Azarbarzin A, Carter SG, et al. Zolpidem increases sleep efficiency and the respiratory arousal threshold without changing sleep apnoea severity and pharyngeal muscle activity. J Physiol. 2020;598(20):4681–92. [ https://doi.org/10.1113/jp280173 ](https://doi.org/10.1113/jp280173) .
[ Article ](https://doi.org/10.1113%2Fjp280173) [ CAS ](/articles/cas-
redirect/1:CAS:528:DC%2BB3cXhs12jtb%2FE) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32864734)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=Zolpidem%20increases%20sleep%20efficiency%20and%20the%20respiratory%20arousal%20threshold%20without%20changing%20sleep%20apnoea%20severity%20and%20pharyngeal%20muscle%20activity&journal=J%20Physiol&doi=10.1113%2Fjp280173&volume=598&issue=20&pages=4681-4692&publication_year=2020&author=Messineo%2CL&author=Eckert%2CDJ&author=Lim%2CR&author=Chiang%2CA&author=Azarbarzin%2CA&author=Carter%2CSG)
57. Stöberl AS, Schwarz EI, Haile SR, Turnbull CD, Rossi VA, Stradling JR, et al. Night-to-night variability of obstructive sleep apnea. J Sleep Res. 2017;26(6):782–8. [ https://doi.org/10.1111/jsr.12558 ](https://doi.org/10.1111/jsr.12558) .
[ Article ](https://doi.org/10.1111%2Fjsr.12558) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=28548301)
[ Google Scholar ](http://scholar.google.com/scholar_lookup?&title=Night-to-
night%20variability%20of%20obstructive%20sleep%20apnea&journal=J%20Sleep%20Res&doi=10.1111%2Fjsr.12558&volume=26&issue=6&pages=782-788&publication_year=2017&author=St%C3%B6berl%2CAS&author=Schwarz%2CEI&author=Haile%2CSR&author=Turnbull%2CCD&author=Rossi%2CVA&author=Stradling%2CJR)
58. Roeder M, Sievi NA, Bradicich M, Grewe FA, Siegfried S, Gaisl T, et al. The accuracy of repeated sleep studies in OSA: a longitudinal observational study with 14 nights of oxygen saturation monitoring. Chest. 2021;159(3):1222–31. [ https://doi.org/10.1016/j.chest.2020.09.098 ](https://doi.org/10.1016/j.chest.2020.09.098) .
[ Article ](https://doi.org/10.1016%2Fj.chest.2020.09.098) [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Abstract&list_uids=32980370)
[ Google Scholar
](http://scholar.google.com/scholar_lookup?&title=The%20accuracy%20of%20repeated%20sleep%20studies%20in%20OSA%3A%20a%20longitudinal%20observational%20study%20with%2014%20nights%20of%20oxygen%20saturation%20monitoring&journal=Chest&doi=10.1016%2Fj.chest.2020.09.098&volume=159&issue=3&pages=1222-1231&publication_year=2021&author=Roeder%2CM&author=Sievi%2CNA&author=Bradicich%2CM&author=Grewe%2CFA&author=Siegfried%2CS&author=Gaisl%2CT)
[ Download references ](https://citation-
needed.springer.com/v2/references/10.1186/s12931-022-02141-3?format=refman&flavour=references)
## Acknowledgements
All of the authors are grateful to the staff in our sleep center and all of
the subjects.
## Funding
The study was granted by grants from Ministry of Science and Technology of the
People’s Republic of China (Grant Nos. 2021ZD0201900, 2021ZD0201902), Shanghai
Municipal Commission of Science and Technology (Grant No.18DZ2260200),
Shanghai Science and Technology Innovation Program of Science and Technology
Commission (Grant No. 20Y11902100), National Natural Science Foundation of
China (Grant Nos. 82071030, 81700896, 81770988, 81970869) and Shanghai Shen-
Kang Hospital Management Center Project (Grant Nos. SHDC2020CR2044B,
SHDC2020CR3056B).
## Author information
Author notes
1. Weijun Huang and Xiaoting Wang contributed equally to this work
### Authors and Affiliations
1. Department of Otorhinolaryngology Head and Neck Surgery, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai, China
Weijun Huang, Xiaoting Wang, Chong Xu, Huajun Xu, Huaming Zhu, Suru Liu,
Jianyin Zou, Jian Guan, Hongliang Yi & Shankai Yin
2. Shanghai Key Laboratory of Sleep Disordered Breathing, 600 Yishan Road, Shanghai, China
Weijun Huang, Xiaoting Wang, Chong Xu, Huajun Xu, Huaming Zhu, Suru Liu,
Jianyin Zou, Jian Guan, Hongliang Yi & Shankai Yin
3. Otolaryngology Institute of Shanghai Jiao Tong University, 600 Yishan Road, Shanghai, China
Weijun Huang, Xiaoting Wang, Chong Xu, Huajun Xu, Huaming Zhu, Suru Liu,
Jianyin Zou, Jian Guan, Hongliang Yi & Shankai Yin
Authors
1. Weijun Huang
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Weijun%20Huang)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Weijun%20Huang)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Weijun%20Huang%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
2. Xiaoting Wang
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Xiaoting%20Wang)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Xiaoting%20Wang)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Xiaoting%20Wang%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
3. Chong Xu
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Chong%20Xu)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Chong%20Xu) [
Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Chong%20Xu%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
4. Huajun Xu
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Huajun%20Xu)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Huajun%20Xu) [
Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Huajun%20Xu%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
5. Huaming Zhu
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Huaming%20Zhu)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Huaming%20Zhu)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Huaming%20Zhu%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
6. Suru Liu
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Suru%20Liu)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Suru%20Liu) [
Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Suru%20Liu%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
7. Jianyin Zou
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Jianyin%20Zou)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Jianyin%20Zou)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Jianyin%20Zou%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
8. Jian Guan
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Jian%20Guan)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Jian%20Guan) [
Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Jian%20Guan%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
9. Hongliang Yi
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Hongliang%20Yi)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Hongliang%20Yi)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Hongliang%20Yi%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
10. Shankai Yin
[ View author publications
](https://www.biomedcentral.com/search?query=author%23Shankai%20Yin)
You can also search for this author in [ PubMed
](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=search&term=Shankai%20Yin)
[ Google Scholar
](http://scholar.google.co.uk/scholar?as_q=&num=10&btnG=Search+Scholar&as_epq=&as_oq=&as_eq=&as_occt=any&as_sauthors=%22Shankai%20Yin%22&as_publication=&as_ylo=&as_yhi=&as_allsubj=all&hl=en)
### Contributions
The corresponding authors are responsible for the authenticity of the data.
All authors made a significant contribution to the work reported (i.e., in the
conception design or execution of the study, acquisition, analysis, or
interpretation of the data, or in all of these areas). WH, JZ, HX, SL, JG, HY,
and SY contributed to the study design, manuscript drafting or revision, or
critical review of the article. WH, XW, CX, HX, and SL contributed to data
collection. WH, JZ, HX, HZ, SL, JG, and HY contributed to the statistical
analyses. All authors have agreed to be accountable for all aspects of the
work. All authors read and approved the final manuscript.
### Corresponding authors
Correspondence to [ Jianyin Zou ](mailto:[email protected]) or [ Hongliang Yi
](mailto:[email protected]) .
## Ethics declarations
### Ethics approval and consent to participate
This study was performed in accordance with the Declaration of Helsinki. The
study protocol was approved by the Ethics Committee of Shanghai Jiao Tong
University Affiliated Sixth People’s Hospital (Approval No: 2019-KY-050[K])
and was registered at the Chinese Clinical Trial Registry (No.
ChiCTR1900025714).
### Consent for publication
We obtained informed consent from all subjects.
### Competing interests
The authors declare that they have no competing interests.
## Additional information
### Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in
published maps and institutional affiliations.
## Supplementary Information
### [ **Additional file 1: Figure S1.** ](https://static-
content.springer.com/esm/art%3A10.1186%2Fs12931-022-02141-3/MediaObjects/12931_2022_2141_MOESM1_ESM.tif)
Prevalence of CC-POSA (a) and APOC-POSA (b) by BMI. APOC, Amsterdam Positional
Obstructive Sleep Apnea Classification; BMI, body mass index; CC, Cartwright
Classification; POSA, positional obstructive sleep apnea; si-POSA, supine-
isolated positional obstructive sleep apnea; sp-POSA, supine-predominant
positional obstructive sleep apnea.
### [ **Additional file 2: Table S1.** ](https://static-
content.springer.com/esm/art%3A10.1186%2Fs12931-022-02141-3/MediaObjects/12931_2022_2141_MOESM2_ESM.docx)
Clinical and Sleep Characteristics of All Subjects (n = 7110).
## Rights and permissions
**Open Access** This article is licensed under a Creative Commons Attribution
4.0 International License, which permits use, sharing, adaptation,
distribution and reproduction in any medium or format, as long as you give
appropriate credit to the original author(s) and the source, provide a link to
the Creative Commons licence, and indicate if changes were made. The images or
other third party material in this article are included in the article's
Creative Commons licence, unless indicated otherwise in a credit line to the
material. If material is not included in the article's Creative Commons
licence and your intended use is not permitted by statutory regulation or
exceeds the permitted use, you will need to obtain permission directly from
the copyright holder. To view a copy of this licence, visit [
http://creativecommons.org/licenses/by/4.0/
](http://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public
Domain Dedication waiver ( [ http://creativecommons.org/publicdomain/zero/1.0/
](http://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data
made available in this article, unless otherwise stated in a credit line to
the data.
[ Reprints and permissions
](https://s100.copyright.com/AppDispatchServlet?title=Prevalence%2C%20characteristics%2C%20and%20respiratory%20arousal%20threshold%20of%20positional%20obstructive%20sleep%20apnea%20in%20China%3A%20a%20large%20scale%20study%20from%20Shanghai%20Sleep%20Health%20Study%20cohort&author=Weijun%20Huang%20et%20al&contentID=10.1186%2Fs12931-022-02141-3©right=The%20Author%28s%29&publication=1465-993X&publicationDate=2022-09-12&publisherName=SpringerNature&orderBeanReset=true&oa=CC%20BY%20%2B%20CC0)
## About this article
[ 
](https://crossmark.crossref.org/dialog/?doi=10.1186/s12931-022-02141-3)
### Cite this article
Huang, W., Wang, X., Xu, C. _et al._ Prevalence, characteristics, and
respiratory arousal threshold of positional obstructive sleep apnea in China:
a large scale study from Shanghai Sleep Health Study cohort. _Respir Res_
**23** , 240 (2022). https://doi.org/10.1186/s12931-022-02141-3
[ Download citation ](https://citation-
needed.springer.com/v2/references/10.1186/s12931-022-02141-3?format=refman&flavour=citation)
* Received : 10 February 2022
* Accepted : 16 August 2022
* Published : 12 September 2022
* DOI : https://doi.org/10.1186/s12931-022-02141-3
### Share this article
Anyone you share the following link with will be able to read this content:
Get shareable link
Sorry, a shareable link is not currently available for this article.
Copy to clipboard
Provided by the Springer Nature SharedIt content-sharing initiative
### Keywords
* [ Positional obstructive sleep apnea ](/search?query=Positional%20obstructive%20sleep%20apnea&facet-discipline="Medicine%20%26%20Public%20Health")
* [ Prevalence ](/search?query=Prevalence&facet-discipline="Medicine%20%26%20Public%20Health")
* [ Respiratory arousal threshold ](/search?query=Respiratory%20arousal%20threshold&facet-discipline="Medicine%20%26%20Public%20Health")
[ Download PDF ](//respiratory-
research.biomedcentral.com/counter/pdf/10.1186/s12931-022-02141-3.pdf)
Advertisement
[
](//pubads.g.doubleclick.net/gampad/jump?iu=/270604982/bmc/respiratory-
research/articles&sz=300x250&pos=MPU1&doi=10.1186/s12931-022-02141-3&type=article&kwrd=Positional
obstructive sleep apnea,Prevalence,Respiratory arousal threshold&pmc=H33134&)
#### Respiratory Research
ISSN: 1465-993X
#### Contact us
* General enquiries: [ [email protected] ](mailto:[email protected])
* [ Read more on our blogs ](https://blogs.biomedcentral.com/)
* [ Receive BMC newsletters ](//www.biomedcentral.com/login)
* [ Manage article alerts ](//www.biomedcentral.com/account)
* [ Language editing for authors ](https://authorservices.springernature.com/go/sn/?utm_source=Website&utm_medium=BMC&utm_campaign=SNAS+Referrals+2022&utm_id=ref2022)
* [ Scientific editing for authors ](https://authorservices.springernature.com/go/sn/?utm_source=Website&utm_medium=BMC&utm_campaign=SNAS+Referrals+2022&utm_id=ref2022)
* [ Policies ](//www.biomedcentral.com/about/policies)
* [ Accessibility ](//www.biomedcentral.com/accessibility)
* [ Press center ](//www.biomedcentral.com/about/press-centre)
* [ Support and Contact ](https://support.biomedcentral.com/support/home)
* [ Leave feedback ](https://biomedcentral.typeform.com/to/VLXboo)
* [ Careers ](//www.biomedcentral.com/about/jobs)
### Follow BMC
* [ BMC Twitter page ](https://twitter.com/biomedcentral)
* [ BMC Facebook page ](https://www.facebook.com/BioMedCentral)
* [ BMC Weibo page ](http://www.weibo.com/biomedcentral)
By using this website, you agree to our [ Terms and Conditions
](//www.biomedcentral.com/terms-and-conditions) , [ Your US state privacy
rights ](https://www.springernature.com/ccpa) , [ Privacy statement
](//www.biomedcentral.com/privacy-statement) and [ Cookies
](//www.biomedcentral.com/cookies) policy. [ Your privacy choices/Manage
cookies ](javascript:void\(0\);) we use in the preference centre.
© 2024 BioMed Central Ltd unless otherwise stated. Part of [ Springer Nature
](https://www.springernature.com) .
*[
DOI
]: Digital Object Identifier
| biology | 941 | https://nn.wikipedia.org/wiki/1889 | 1889 | 1889 (romartal MDCCCLXXXIX) var eit normalår som byrja på ein tysdag i den gregorianske kalenderen og eit normalår som byrja på ein sundag i den julianske kalenderen.
Hendingar
Utlandet
30. januar: Mayerlingdramat fann stad i Austerrike.
11. februar: Japan tok i bruk Meiji-grunnlova.
4. mars: Benjamin Harrison vart president i USA etter Grover Cleveland.
9. mars: den etiopiske keisaren Yohannes IV døydde, og Menelik II vart ny keisar.
31. mars: Eiffeltårnet blei innvigd som porten til Verdsutstillinga i Paris i høve hundreårsmarkeringa av den franske revolusjonen.
15. november: keisar Pedro II av Brasil vart avsett i eit militært statskupp og Marechal Deodoro da Fonseca erklærte landet ein republikk.
Leiarane for det mislukka Zuluopprøret i 1888 vart sende i eksil til St. Helena.
Charter Gas Engine Co. i USA bygde den fyrste traktoren i historia med intern forbrenningsmotor.
Emile Berliner innførte ei grammofonplate med ein diameter på 12.7 mm.
Emile Berliner stifta Deutsche Grammophon Gesellschaft.
Noreg
26. juni: Lov om folkeskolen innførte 7-årig skuleplikt og endra namnet på skulane frå allmugeskule til folkeskulen.
Fyrstikkarbeidarstreiken i Kristiania var den første store organiserte streiken i norsk arbeidarhistorie.
Det norske Arbeidarpartiet fekk sosialistisk program.
Fødde
3. februar: Risto Ryti, finsk president
16. april: Charlie Chaplin, britisk skodespelar
20. april: Adolf Hitler, austerriksk-tysk statsleiar
26. april: Ludwig Wittgenstein, tysk filosof
27. april: Arnulf Øverland, norsk forfattar
28. april: Sjur Bygd, norsk bonde og forfattar
29. april: Ragnvald Vaage, norsk bonde og forfattar
18. juni: Per Krohg, norsk målar
25. august: Aslaug Vaa, norsk forfattar
3. oktober: Carl von Ossietzky, tysk pasifist og fredsprisvinnar
14. november: Jawaharlal Nehru, indisk statsminister
17. november: Gustav Indrebø, norsk språkgranskar og målmann
20. november: Edwin Hubble, astronom frå USA
Døde
23. januar: Alexandre Cabanel, fransk målar
5. februar: Ole Jacob Broch, norsk matematikar og embetsmann
8. mars: John Ericsson, svensk-amerikansk oppfinnar og ingeniør
17. november: Ketil Motzfeldt, norsk embetsmann og politikar
22. oktober: Synnøve Riste, norsk målkvinne
22. november: Georg Harbitz, norsk prest og politikar
6. desember: Jefferson Davis, USA-amerikansk president
Kjelder | norwegian_nynorsk | 1.223579 |
sense_dimmed_sleep/Parietal_lobe.txt | The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus.
The parietal lobe integrates sensory information among various modalities, including spatial sense and navigation (proprioception), the main sensory receptive area for the sense of touch in the somatosensory cortex which is just posterior to the central sulcus in the postcentral gyrus, and the dorsal stream of the visual system. The major sensory inputs from the skin (touch, temperature, and pain receptors), relay through the thalamus to the parietal lobe.
Several areas of the parietal lobe are important in language processing. The somatosensory cortex can be illustrated as a distorted figure – the cortical homunculus (Latin: "little man") in which the body parts are rendered according to how much of the somatosensory cortex is devoted to them. The superior parietal lobule and inferior parietal lobule are the primary areas of body or spatial awareness. A lesion commonly in the right superior or inferior parietal lobule leads to hemineglect.
The name comes from the parietal bone, which is named from the Latin paries-, meaning "wall".
Structure[edit]
Animation. Parietal lobe (red) of left cerebral hemisphere.
The parietal lobe is defined by three anatomical boundaries: The central sulcus separates the parietal lobe from the frontal lobe; the parieto-occipital sulcus separates the parietal and occipital lobes; the lateral sulcus (sylvian fissure) is the most lateral boundary, separating it from the temporal lobe; and the longitudinal fissure divides the two hemispheres. Within each hemisphere, the somatosensory cortex represents the skin area on the contralateral surface of the body.
Immediately posterior to the central sulcus, and the most anterior part of the parietal lobe, is the postcentral gyrus (Brodmann area 3), the primary somatosensory cortical area. Separating this from the posterior parietal cortex is the postcentral sulcus.
The posterior parietal cortex can be subdivided into the superior parietal lobule (Brodmann areas 5 + 7) and the inferior parietal lobule (39 + 40), separated by the intraparietal sulcus (IPS). The intraparietal sulcus and adjacent gyri are essential in guidance of limb and eye movement, and—based on cytoarchitectural and functional differences—is further divided into medial (MIP), lateral (LIP), ventral (VIP), and anterior (AIP) areas.
Function[edit]
Functions of the parietal lobe include:
Two point discrimination – through touch alone without other sensory input (e.g. visual)
Graphesthesia – recognizing writing on skin by touch alone
Touch localization (bilateral simultaneous stimulation)
The parietal lobe plays important roles in integrating sensory information from various parts of the body, knowledge of numbers and their relations, and in the manipulation of objects. Its function also includes processing information relating to the sense of touch. Portions of the parietal lobe are involved with visuospatial processing. Although multisensory in nature, the posterior parietal cortex is often referred to by vision scientists as the dorsal stream of vision (as opposed to the ventral stream in the temporal lobe). This dorsal stream has been called both the "where" stream (as in spatial vision) and the "how" stream (as in vision for action). The posterior parietal cortex (PPC) receives somatosensory and visual input, which then, through motor signals, controls movement of the arm, hand, and eyes.
Various studies in the 1990s found that different regions of the posterior parietal cortex in macaques represent different parts of space.
The lateral intraparietal (LIP) area contains a map of neurons (retinotopically-coded when the eyes are fixed) representing the saliency of spatial locations, and attention to these spatial locations. It can be used by the oculomotor system for targeting eye movements, when appropriate.
The ventral intraparietal (VIP) area receives input from a number of senses (visual, somatosensory, auditory, and vestibular). Neurons with tactile receptive fields represent space in a head-centered reference frame. The cells with visual receptive fields also fire with head-centered reference frames but possibly also with eye-centered coordinates
The medial intraparietal (MIP) area neurons encode the location of a reach target in eye-centered coordinates.
The anterior intraparietal (AIP) area contains neurons responsive to shape, size, and orientation of objects to be grasped as well as for manipulation of the hands themselves, both to viewed and remembered stimuli. The AIP has neurons that are responsible for grasping and manipulating objects through motor and visual inputs. The AIP and ventral premotor together are responsible for visuomotor transformations for actions of the hand.
More recent fMRI studies have shown that humans have similar functional regions in and around the intraparietal sulcus and parietal-occipital junction. The human "parietal eye fields" and "parietal reach region", equivalent to LIP and MIP in the monkey, also appear to be organized in gaze-centered coordinates so that their goal-related activity is "remapped" when the eyes move.
Emerging evidence has linked processing in the inferior parietal lobe to declarative memory. Bilateral damage to this brain region does not cause amnesia however the strength of memory is diminished, details of complex events become harder to retrieve, and subjective confidence in memory is very low. This has been interpreted as reflecting either deficits in internal attention, deficits in subjective memory states, or problems with the computation that allows evidence to accumulate, thus allowing decisions to be made about internal representations.
Clinical significance[edit]
Features of parietal lobe lesions are as follows:
Unilateral parietal lobe
Contralateral hemisensory loss
Astereognosis – inability to determine 3-D shape by touch.
Agraphaesthesia – inability to read numbers or letters drawn on hand, with eyes shut.
Contralateral homonymous inferior quadrantanopia
Asymmetry of optokinetic nystagmus (OKN)
Sensory seizures
Dominant hemisphere
Conduction aphasia
Dyslexia – a general term for disorders that can involve difficulty in learning to read or interpret words, letters, and other symbols
Apraxia – inability to perform complex movements in the presence of normal motor, sensory and cerebellar function
Gerstmann syndrome – characterized by acalculia, agraphia, finger agnosia, and left-right disorientation
Non-dominant hemisphere
Contralateral hemispatial neglect
Constructional apraxia
Dress apraxia
Anosognosia – lack of awareness of the existence of one's disability
Bilateral hemispheres
Bálint's syndrome
Damage to this lobe in the right hemisphere results in the loss of imagery, visualization of spatial relationships and neglect of left-side space and left side of the body. Even drawings may be neglected on the left side. Damage to this lobe in the left hemisphere will result in problems in mathematics, long reading, writing, and understanding symbols. The parietal association cortex enables individuals to read, write, and solve mathematical problems. The sensory inputs from the right side of the body go to the left side of the brain and vice versa.
The syndrome of hemispatial neglect is usually associated with large deficits of attention of the non-dominant hemisphere. Optic ataxia is associated with difficulties reaching toward objects in the visual field opposite to the side of the parietal damage. Some aspects of optic ataxia have been explained in terms of the functional organization described above.
Apraxia is a disorder of motor control which can be referred neither to "elemental" motor deficits nor to general cognitive impairment. The concept of apraxia was shaped by Hugo Liepmann about a hundred years ago. Apraxia is predominantly a symptom of left brain damage, but some symptoms of apraxia can also occur after right brain damage.
Amorphosynthesis is a loss of perception on one side of the body caused by a lesion in the parietal lobe. Usually, left-sided lesions cause agnosia, a full-body loss of perception, while right-sided lesions cause lack of recognition of the person's left side and extrapersonal space. The term amorphosynthesis was coined by D. Denny-Brown to describe patients he studied in the 1950s.
Can also result in sensory impairment where one of the affected person's senses (sight, hearing, smell, touch, taste and spatial awareness) is no longer normal.
See also[edit]
Lobes of the brain
Temporoparietal junction | biology | 373153 | https://sv.wikipedia.org/wiki/Temporallob | Temporallob | Temporallob, tinninglob eller lobus temporalis är en av de fyra större hjärnloberna i den cerebrala barken hos däggdjur. Den fyller huvudsakligen funktioner relaterade till hörsel och i semantik både i tal och syn. Temporalloben innehåller hippocampus och är därför även involverad även i minnesbildningen. Temporal refererar till tinningarna.
Anatomi
Temporalloberna fördelar sig på så vis att det finns en för varje hjärnhalva, således en höger och en vänster. De är båda lokaliserade under den laterala fåran, även kallad sidofåran, och kan vidare liknas med den placering en tumme har om den sätts på utsidan av en stängd näve (Se bild). Temporallobens struktur inkluderar det limbiska systemet, amygdala, Wernickes område, det primära hörselcentrat samt hippocampus. Utöver det har den neuronala nätverk till och från hela hjärnan. Faktum är att dess interna nätverk är väldigt starkt, med både afferenta projektioner från sinnessystemet samt efferenta projektioner till parietala och frontal associerade områden, det limbiska system och de basala ganglierna. De båda temporalloberna binds främst samman av corpus callosum, även kallad hjärnbalken. Tinningloben kan delas in i fyra funktionella zoner: auditiva processer, visuella processer, emotioner och spatial navigation samt objekt minne.
Några olika "vägar" för informationsflödet
En hierarkisk sensorisk väg: Den här vägen är till för igenkännandet av stimulus. Härigenom kommer information från det primär och sekundära hörselcentral och de visuella områdena, de kommer då till temporalloben. Det är dock viktigt att komma ihåg att denna väg egentligen är två parallella vägar där det auditiva och det visuella är separerade från varandra.
En bakre auditiv väg: Detta nätverk består av projektioner från hörselområdena till den bakre parietala barken. Det är även troligt att denna väg spelar en stor roll i att upptäcka och uppdatera om det spatiala läget genom auditiva impulser.
Den polymodala gångvägen: Här finns en mängd parallella projektioner från de visuella och auditiva associationsområdena som senare då skickas till de polymodala regionerna. Denna väg ska troligtvis vara underliggande någon stimulus kategorisering.
En mittre temporal projektion: Denna är väldigt viktig för långtidsminnet då den skickar information först från de visuella och auditiva områdena till den mittre temporala barken innan det slussas vidare till antingen hippocampus eller amygdala, eventuellt till båda. Om denna väg utsätts för skada skulle det resultera i stor disfunktionalitet i hippocampus aktivitet.
En frontallobs projektion: Den här serien av parallella projektioner är nödvändig för många aspekter av rörelsekontroll, korttidsminnet och affekter. Den går således ändå från temporallobernas områden till frontalloben.
Alla dessa vägar spelar i sin tur stor roll i temporallobernas olika funktioner.
Funktion
Temporalloberna har flera olika funktionsområden, här följer några av dem:
Ljud- och språk relaterade funktioner:
- Denna lob är en väldigt effektiv mottagare av ljudinformation från det auditiva området, ovan nämns det hur denna information letar sig hit. Det ska även vara diskuterat att den vänstra tinningloben är den som analyserar och tolkar språkljud medan den högra skall analysera musikljud.
- Då Wernickes område är placerat i tinningloberna är det här som hjärnan skall förstå språk, både det vi läser och det vi hör.
Minnesregistrering:
- Hippocampus står för inlärning och att förbereda minneslagring för långtidsminnet. Den spelar även en stor roll i att organisera minnet av objekt i tid och rum.
Reaktionsskapande och analysering av omvärlden:
- Amygdala bidrar med emotionskryddningen av sensoriska inmatningen och minnen genom att kontrollera samt utlösa känslomässiga reaktioner. Ofta som respons på olika sinnesintryck, särskilt synintryck. Exempelvis kan dessa känsloreaktioner vara vrede, rädsla eller nyfikenhet. Det har även spekulerats om att luktsinnet ska ha en bidragande roll här, det finns dock inte tillräckligt med fakta för detta ännu.
- Ytterligare ett användningsområde för temporalloberna skall vara att den kan analysera och uppfatta sociala rörelser eller antydan till rörelser. Detta med hjälp av "Superior temporal sulcus", som förkortas STS, och är en del av temporalloben. Den information som ges från dessa analyser är särskilt viktig i social kognition och theory of mind då de tillåter oss att skapa hypoteser om andra människors känsloliv och intentioner. Informationen dras från små ögonrörelser, huvudrörelser och munrörelser till handrörelser och mer distinkta ansiktsuttryck.
Igenkännande funktioner:
- Utöver det jobbar dessa lober med att aktivt analysera och tolka information som skickas från nackloberna. Det handlar således om former och färger i vår omgivning, detta resulterar i att vi kan känna igen samt benämna objekt i vår omvärld.
Navigering:
- Sist men inte minst sköter temporalloberna rumslig orientering. Så att en ska kunna navigera i vardagen eller med andra ord: "Vi vet var vi är någonstans, hur vi tog oss hit och hur vi skall hitta hem" Detta syftar både på objekt placering samt vägledning av personens egna rörelser. För att vi ska kunna röra vår arm mot ett visst mål, exempelvis kanske vi vill ta tag i någons hand, behöver vi vara medvetna om var vår arm ursprungligen befinner sig samt var den andres hand är. Sedan behöver vi veta hur vi ska vinkla vår egen hand för att den ska kunna sammanfogas korrekt med den andres och liknande. Väldigt för oss enkla rörelser bygger egentligen på flera komplexa system och det är viktigt att de fungerar som de skall.
För att klara av denna uppgift behöver vår uppdatering om omvärlden ske så effektivt som möjligt. Då använder sig temporalloberna av ett så kallat "cross-modal matching", ett system som bland annat matchar den visuella och auditiva informationen och gör att de sammanfogas till en bild av verkligheten.
Skador på temporalloberna
Då temporallobernas generella funktioner innehåller navigation, sensorisk förmåga och viss känslobehandling är det kanske självklart att en avsaknad av detta skulle ställa till med stor problematik för en person och dess beteende. Exempelvis skulle det kunna resultera i en oförmåga att uppfatta eller komma ihåg olika händelser, detta inkluderar då en tydligt brist av språkförmågan och känslobehandlingen. Däremot skulle dessa människor eventuellt kunna uppfattas "normala" vid första åsynen då de skulle kunna använda det dorsala visuella systemet för att visuellt vägleda sig själva.
Eftersom Tinningloberna både behandlar visuella och auditiva system kan en skada i detta område leda till såväl sämre förmåga att lokalisera ljud som att förlora förmågan att känna igen komplexa visuella stimulin. En skada på Wernickes område kan även leda till en oförmåga att förstå både skrivet och talat språk.
En skada på hippocampus skulle i sin tur kunna leda till svårigheter att minnas saker som precis skett, däremot är minnen som skapats och lagrats före skadan fortfarande intakta efter skadan. Detta är en konsekvens av att hippocampus tros omvandla nya minnen till ett långtidsminne. En skada i detta område skulle leda till att nya minnen inte "stannar kvar" och blir långtidsminnen.
Höger eller vänster?
En viss asymmetri mellan loberna verkar existera då skador i den vänstra temporalloben är associerat med negativa konsekvenser på verbalt minne, medan skador på högra tinningloben kopplas till negativa konsekvenser på det icke-verbala minnet, exempelvis ansiktsminnet. Ytterligare verkar skador på den vänstra halvan resultera i sämre bearbetning av språkljud, då däremot skador på den högra halvan pekar på sämre bearbetning av andra ljud som är mer musikaliskt inriktade. Dessutom är det endast defekter i högra tinningloben som leder till svårigheter med att känna igen ansikten och ansiktsuttryck. Genom detta verkar som sagt en viss asymmetri finnas, vissa påstår att de olika halvorna skall ha olika roller i både social kognition och individers personlighet genom det. Huruvida det nu existerar skillnader mellan de båda halvorna av tinningloberna eller inte är det åtminstone klart att en avsaknad av båda dessa lober skulle dubblera symtom och skapa dramatiska effekter på både minne och affekt.
Sjukdomar:
Picks sjukdom- kallas även för frontaltemporal amnesi och är en typ av frontallobsdemens. Däremot är den största förlusten av nervceller lokaliserade i hippocampus och amygdala vilket gör att den även kan klassas som en temporallobssjukdom. De emotionella symtomen inkluderar humörsvängningar (som patienten kan vara omedveten om), ett sämre uppmärksamhetsspann och aggressivt beteende mot både dem själva och andra. Språksymtomen för denna sjukdom inkluderar talsvårigheter, svårigheter med att skriva och läsa och förluster i ordförrådet. Det kan även leda till total stumhet hos patienterna allteftersom. Personer med denna sjukdom får även svårigheter med att organisera, påbörja och genomföra aktiviteter samt ett sämre socialt omdöme.
Temporallobsepilepsi eller tinningslobsepilepsi- en form av epilepsi som är kopplat till temporalloben. Det är en kronisk sjukdom som kategoriseras av olika återkommande anfall. Dessa anfall kan vara olika stora och vara olika länge. Symtom inkluderar hallucinationer, allt från visuella till auditiva, samt en oförmåga att bearbeta semantiska och episodiska minnen.
Se även
Frontallob
Occipitallob
Parietallob
Referenser
Storhjärnan | swedish | 0.612276 |
sense_dimmed_sleep/nonobesepatientswith.txt | __
[ 
](https://www.itamar-medical.com/ "Itamar Medical")
Home Sleep Apnea Testing Products
* Products & Services
* Products
* • Home Sleep Apnea Testing
* [ WatchPAT®️ 300 ](https://www.itamar-medical.com/professionals/watchpat-300/)
* [ WatchPAT®️ ONE ](https://www.itamar-medical.com/professionals/disposable-hsawatchpat-one/)
* • Endothelial Dysfunction
* [ EndoPAT®️ ](https://www.itamar-medical.com/professionals/endopat/)
* [ EndoPAT®️X ](https://www.itamar-medical.com/professionals/endopat-x/)
* [ PAT®️ Technology ](https://www.itamar-medical.com/pat-peripheral-arterial-tone-technology/)
* Services
* • Home Sleep Apnea Testing
* [ WatchPAT®️ Direct ](https://www.itamar-medical.com/professionals/watchpat-direct/)
* [ WatchPAT®️ Solutions ](https://www.itamar-medical.com/cardiology/watchpat-solutions/)
* [ SleePATh ®️ ](https://www.itamar-medical.com/professionals/sleepath/)
* [ Arrhythmia Detection ](https://www.itamar-medical.com/arrhythmia-detection/)
* Healthcare Professionals
* Sleep Medicine
* [ CARDIO SLEEP PUBLICATIONS ](https://www.itamar-medical.com/professionals/publications/)
* [ Sleep Apnea Blog ](https://www.itamar-medical.com/professionals/sleep-apnea-blog/)
* [ Videos ](https://www.itamar-medical.com/professionals/videos/)
* [ WatchPAT ®️ Scoring Guidelines Webinar ](https://www.itamar-medical.com/sleepmedicine-webinars/)
* Cardiology
* [ WatchPAT®️ Solutions ](https://www.itamar-medical.com/cardiology/watchpat-solutions/)
* [ Cardio Sleep Clinical Testimonials ](https://www.itamar-medical.com/professionals/clinical-testimonials/)
* [ Cardio Sleep Blog ](https://www.itamar-medical.com/professionals/cardio-sleep-blog-2/)
* [ CARDIO SLEEP PUBLICATIONS ](https://www.itamar-medical.com/professionals/publications/)
* [ SLEEP APNEA AND CARDIOLOGY: Clinical Research ](https://www.itamar-medical.com/clinical-research/)
* Dental
* [ Dental Blog ](https://www.itamar-medical.com/professionals/dental-blog-2/)
* Support
* Manuals and Tutorials
* [ WatchPAT®️ Tutorials ](https://www.itamar-medical.com/support/watchpat-tutorials/)
* [ CloudPAT® Tutorials ](https://www.itamar-medical.com/cloudpat-tutorials/)
* [ Manuals ](https://www.itamar-medical.com/support/manuals/)
* Reimbursement
* [ WatchPAT®️ Reimbursement ](https://www.itamar-medical.com/watchpat-reimbursement/)
* [ EndoPAT®️ Reimbursement ](https://www.itamar-medical.com/reimbursement/)
* [ Upgrade and Installation ](https://www.itamar-medical.com/support/upgrades-installation/)
* [ Product Bulletins ](https://www.itamar-medical.com/support/announcements-2/)
* [ Legal and Terms and Conditions ](https://www.itamar-medical.com/terms-and-conditions/)
* [ Customer Community ](https://itamar-medical.my.site.com/login?ec=302&startURL=%2Fs%2F)
* International
* [ Spanish ](https://es.itamar-medical.com/)
* [ French ](https://www.watchpat.fr/)
* CloudPAT Servers
* [ USA ](https://cloudpat.itamar-medical.com/)
* [ UK ](https://cloudpat-uk.itamar-medical.com/)
* [ EU ](https://cloudpat-eu.itamar-medical.com/)
* [ AU ](https://cloudpat-au.itamar-medical.com/)
* [ About Us ](https://www.itamar-medical.com/about-us/)
* [ Company Profile ](https://www.itamar-medical.com/company-profile/)
* [ Global Presence ](https://www.itamar-medical.com/global-presence/)
* [ WatchPAT® ONE Green Program ](https://www.itamar-medical.com/watchpat-one-green-program/)
* [ ZOLL Itamar Events ](https://www.itamar-medical.com/about-us/events/)
* [ Careers ](https://www.zoll.com/contact/careers-at-zoll)
* [ ZOLL Itamar Corporate News ](https://www.itamar-medical.com/news-media/)
* [ Contact ](https://www.itamar-medical.com/contact-us/)
[ CONTACT US contact ](/contact-us/)
[ Home ](https://www.itamar-medical.com/) » [ Articles ](https://www.itamar-
medical.com/articles/) » Nonobese patients with obstructive sleep apnea: what
is the effect of low respiratory arousal threshold (LRAT)?
#
Nonobese patients with obstructive sleep apnea: what is the effect of low
respiratory arousal threshold (LRAT)?
* 
Obstructive sleep apnea (OSA) is well-established as a disease that is also a
risk factor for many other health problems. Studies continue to help increase
understanding of why people develop sleep apnea, which people are more
susceptible, when to test for it, how to treat it properly, and so forth. A
recent study added to this knowledge, starting with a closer examination of
OSA, a look at obesity, and then an uncommon possible influencing factor 1 .
**The Pathophysiology of OSA remains complex**
The anatomical predisposition factors are present in all patients (in 30% of
patients without other factors). In 70% of cases, there are 1 or more
associated _non_ -anatomical pathophysiologic factors. This is responsible for
a different phenotype of the disease. 2
There are 4 pathophysiologic factors involved in the pathogenesis of OSA:
* Anatomic, which can lead to greater collapse of the upper airways in **nonobese patients**
* Instability of ventilatory control, also known as high loop gain
* Neuromuscular inefficiency of the dilator muscles of the upper airways
* Increased propensity for nocturnal awakenings due to respiratory stimuli or a reduced awakening threshold, known as **low arousal threshold** ( **also called low** **_respiratory_ ** **arousal threshold, or LRAT** ). 2
**Nonobese patients with OSA: looking at an unusual cause**
A recent study looked specifically at the role of LRAT in nonobese patients.
Nonobese patients with OSA are a subgroup of individuals with clinical,
polysomnographic, and pathophysiologic features. 1 Little evidence exists
regarding the role of LRAT. 1 But, because there could be a non-anatomical
pathological prevalent trait, this factor could explain **the difficulty in
treating OSA in nonobese patients** . 1
**How prevalent is low arousal threshold?**
**Low arousal threshold is present in 30% to 50% of all patients with OSA.**
** 2 ** Disturbingly, another study showed that LRAT was observed in more
than 60% of African American patients evaluated for OSA. This study also
showed a significantly higher LRAT score in African American females,
nonsmokers, patients with body mass index (BMI) <25, and patients with _mild_
sleep apnea severity. 3
**Nonobesity by the numbers**
Nonobese patients are those with a BMI <30 kg/m 2 . 1 **Approximately 20%
of adults with OSA are nonobese.** 4 The number of people with OSA is thought
to be as many as 18 million in the United States—1 in 15 adults—with 80%
undiagnosed. Some estimates are much higher.
**Uncommon characteristics**
OSA in nonobese patients is usually less severe and less frequent. However, it
is **essential to identify these patients because they are 4 times more likely
to develop hypertension than obese individuals without OSA** . 5 Nonobese
patients are **at risk for early atherosclerosis—approximately 2.7 times
more** than obese patients without OSA, and **this risk increases** as the
severity of the syndrome increases. 6 Also, **nonobese patients with OSA are
usually younger, so early detection and care could reduce long-term risk
associated with the syndrome** . 7
**Diagnosis and treatment**
An in-laboratory overnight sleep study using polysomnography (PSG) is
routinely indicated for the diagnosis of respiratory sleep disorders. The
study authors point out that an excellent, alternative is nocturnal portable
monitoring (PM), often known as home sleep apnea tests, or HSATs.
The treatment of choice is continuous positive airway pressure (CPAP);
however, **nonobese patients with OSA with a low arousal threshold have poorer
adherence to CPAP therapy** . 8 CPAP may not be the right therapy for
everyone. For some patients, other approaches such as mandibular advancement
devices (MADs), maxillofacial surgery, hypoglossal nerve stimulation, or a
pharmacological approach with targeted therapies may be more appropriate than
CPAP. 8 Non-anatomic interventions (e.g., non-myorelaxant sedatives) to
increase the threshold for arousal, alone, or in combination with existing
therapies (e.g., CPAP or oral appliances), may yield greater therapeutic
success in this group of patients. 2 Improved understanding of the
pathophysiology of OSA in recent years provides an opportunity to develop
individualized therapies based on subpopulations and mechanisms. 1
The study authors believe that further pathophysiologic studies are needed to
better clarify the role of low arousal threshold in patients with OSA and in
the nonobese subgroup.
REFERENCES:
1\. Antonaglia C, Passuti G. Obstructive sleep apnea syndrome in non-obese
patients. _Sleep Breath._ 2021\. [ doi: 10.1007/s11325-021-02412-1
](https://doi.org/10.1007/s11325-021-02412-1)
2\. Eckert DJ, White DP, Jordan AS, Malhotra A, Wellman A. Defining phenotypic
causes of obstructive sleep apnea. Identification of novel therapeutic
targets. _Am J Respir Crit Care Med_ . 2013;188(8):996-1004. [ doi:
10.1164/rccm.201303-0448OC ](about:blank)
3\. Moghalu O, Whitesell P, Kwagyan J. Low respiratory arousal threshold
(LRAT) in African Americans with obstructive sleep apnea (OSA).
_Neurology_ . 2020;94(15 suppl):2740.
4\. Heinzer R, Vat S, Marques-Vidal P, et al. Prevalence of sleep-disordered
breathing in the general population: the HypnoLaus study. _Lancet Respir Med._
2015;3(4):310-318. [ doi: 10.1016/S2213-2600(15)00043-0 ](about:blank)
5\. Bixler EO, Vgontzas AN, Lin HM, et al. Prevalence of sleep-disordered
breathing in women: effects of gender. _Am J Respir Crit Care Med_ .
2001;163(3 Pt 1):608-613. [ doi: 10.1164/ajrccm.163.3.9911064 ](about:blank)
6\. Luyster FS, Kip KE, Aiyer AN, Reis SE, Strollo PJ. Relation of obstructive
sleep apnea to coronary artery calcium in non-obese versus obese men and women
aged 45–75 years. _Am J Cardiol_ . 2014;114(11):1690-1694. [ doi:
10.1016/j.amjcard.2014.08.040 ](about:blank)
7\. Frey WC, Pilcher J (2003) Obstructive sleep-related breathing disorders in
patients evaluated for bariatric surgery. Obes Surg 13(5):676–683. [
https://doi.org/10.1381/096089203322509228
](https://doi.org/10.1381/096089203322509228)
8\. Gray EL, McKenzie DK, Eckert DJ. Obstructive sleep apnea without obesity
is common and difficult to treat: evidence for a distinct pathophysiological
phenotype. _J Clin Sleep Med_ . 2017;13(1):81-88. [ doi: 10.5664/jcsm.6394
](about:blank)
CONTACT US
To reach our customer support please send an email to [ [email protected]
](/cdn-cgi/l/email-
protection#38514c5955594a154b4d4848574a4c7842575454165b5755)
Salutation
__
Mr. Ms. Mrs. Dr. Prof. Assoc. Prof Assis. Prof. Sir.
Email
First Name
Last Name
Telephone
Specialty
__
Sleep Medicine Cardiology Pulmonology ENT Dental Neurology Primary Care
Medicine Other
Country
__
Afghanistan Aland Islands Albania Algeria American Samoa Andorra Angola
Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba
Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados
Belarus Belgium Belize Benin Bermuda Bhutan Bolivia Bonaire Bosnia and
Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory
Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada
Cape Verde Cayman Islands Central African Republic Chad Chile China
Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo,
the Democratic Republic of the Cook Islands Costa Rica Cote d'Ivoire
Croatia Cuba Curacao Cyprus Czech Republic Denmark Djibouti Dominica
Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea
Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland
France French Guiana French Polynesia French Southern Territories Gabon
Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada
Guadeloupe Guam Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti
Heard Island and McDonald Islands Holy See (Vatican City State) Honduras
Hong Kong Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq
Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan
Kazakhstan Kenya Kiribati Korea, Democratic People's Republic of Korea,
Republic of Kuwait Kyrgyzstan Lao People's Democratic Republic Latvia
Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania
Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar
Malawi Malaysia Maldives Mali Malta Marshall Islands Martinique
Mauritania Mauritius Mayotte Mexico Micronesia, Federated States Moldova,
Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique
Myanmar Namibia Nauru Nepal Netherlands Netherlands Antilles New
Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island
Northern Mariana Islands Norway Oman Pakistan Palau Palestinian Territory
Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland
Portugal Qatar Reunion Romania Russian Federation Rwanda Saint
Barthelemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and
Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon
Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe
Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint
Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South
Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri
Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland
Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of
Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia
Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine
United Arab Emirates United Kingdom United States Uruguay US Minor
Outlying Islands US Virgin Islands Uzbekistan Vanuatu Venezuela,
Bolivarian Republic of Viet Nam Virgin Islands, British Wallis and Futuna
Western Sahara Yemen Zambia Zimbabwe
State
__
Alabama Alaska Arizona Arkansas California Colorado Connecticut
Delaware District of Columbia Florida Georgia Hawaii Idaho Illinois
Indiana Iowa Kansas Kentucky Louisiana Maine Maryland Massachusetts
Michigan Minnesota Mississippi Missouri Montana Nebraska Nevada New
Hampshire New Jersey New Mexico New York North Carolina North Dakota
Ohio Oklahoma Oregon Pennsylvania Puerto Rico Rhode Island South
Carolina South Dakota Tennessee Texas Utah Vermont Virgin Islands
Virginia Washington Washington DC West Virginia Wisconsin Wyoming
Zip
Message
I want to receive additional information and marketing material.
Your information will be handled according to our [ Privacy Policy ](/itamar-
medical-privacy-policy-final-230919-2/)
Send
[ Data Protection ](https://www.itamar-medical.com/data-protection/)
[ PRIVACY POLICY FOR END USERS ](https://www.itamar-
medical.com/privacy_policy.htm)
[ PRIVACY POLICY FOR WEBSITE VISITORS & BUSINESS CONTACTS
](https://www.itamar-medical.com/website_privacy_policy.html)
[ Cookie Policy ](https://www.itamar-medical.com/wp-
content/uploads/2019/10/Itamar-Medical-Revised-Cookie-Policy-Clean-092922.pdf)
[ Terms and Conditions of Sale ](https://www.itamar-medical.com/wp-
content/uploads/2022/01/IMI-G4-Terms-and-Conditions-of-Sale-09.2020.pdf)
[ Home Sleep Apnea Test ](https://www.itamar-medical.com/articles/testing-
your-patients-sleep-apnea-at-home/)
[ Itamar Medical - Home Sleep Testing Company Profile ](https://www.itamar-
medical.com/company-profile/)
[ WatchPAT Home Sleep Study Device ](https://www.itamar-
medical.com/patients/watchpat-home-sleep-testing/)
[ Endothelial Dysfunction ](https://www.itamar-medical.com/endothelial-
dysfunction/)
[ Itamar Medical: Medical Device Company & Manufacturer ](https://www.itamar-
medical.com/company-profile/)
[ Diagnosing Sleep Apnea ](https://www.itamar-medical.com/professionals/total-
sleep-solution/)
[ CONTACT US ](https://www.itamar-medical.com/contact-us/)
[ __ ](https://www.facebook.com/ItamarMedical) [ __
](https://twitter.com/itamarmedical1?lang=en) [ __
](https://www.linkedin.com/company/itamar-medical/)
© ZOLL Itamar Ltd.
Site by [ Imaginet ](http://imaginet.co.il)
© Itamar Medical Ltd.
Site by [ Imaginet ](http://imaginet.co.il)
When using the marks in our publications and this website, we used the
appropriate ™️, ℠, or ®️. The ®️ symbol is used to indicate registrations in
the U.S. and the territories listed in [ https://www.itamar-medical.com/terms-
and-conditions/ ](https://www.itamar-medical.com/terms-and-conditions/) and
this should not mean that such trademarks are necessarily registered in other
countries. For example, WatchPAT®️ is a trademark of Itamar Medical Ltd a
subsidiary of ZOLL Medical Corporation, in the United States and/or other
countries. All other trademarks are the property of their respective owners.,
registered in the U.S. and the applicable territories listed in [
https://www.itamar-medical.com/terms-and-conditions/ ](https://www.itamar-
medical.com/terms-and-conditions/) only.
Menu
* Placeholder
* CloudPAT Servers
* [ USA ](https://cloudpat.precisemd.com/)
* [ UK ](https://cloudpatuk.precisemd.com/)
* [ EU ](https://cloudpateu.precisemd.com/)
* [ HEALTHCARE PROFESSIONALS ](https://www.itamar-medical.com/professionals/)
* Products
* • Home Sleep Apnea Testing
* [ WatchPAT ®️ 300 ](https://www.itamar-medical.com/professionals/watchpat-300/)
* [ WatchPAT®️ ONE ](https://www.itamar-medical.com/professionals/disposable-hsawatchpat-one/)
* [ PAT ®️ Technology ](https://www.itamar-medical.com/pat-peripheral-arterial-tone-technology/)
* • Endothelial Dysfunction
* [ EndoPAT ®️ ](https://www.itamar-medical.com/professionals/endopat/)
* [ EndoPAT ®️ X ](https://www.itamar-medical.com/professionals/endopat-x/)
* Services
* • Home Sleep Apnea Testing
* [ WatchPAT®️ Direct ](https://www.itamar-medical.com/professionals/watchpat-direct/)
* [ WatchPAT®️ Solutions ](https://www.itamar-medical.com/cardiology/watchpat-solutions/)
* [ SleePATh ®️ ](https://www.itamar-medical.com/professionals/sleepath/)
* [ Arrhythmia Detection ](https://www.itamar-medical.com/arrhythmia-detection/)
* Support
* Manuals and Tutorials
* [ WatchPAT® Tutorials ](https://www.itamar-medical.com/support/watchpat-tutorials/)
* [ CloudPAT® Tutorials ](https://www.itamar-medical.com/cloudpat-tutorials/)
* [ Manuals ](https://www.itamar-medical.com/support/manuals/)
* Reimbursement
* [ WatchPAT ®️ Reimbursement ](https://www.itamar-medical.com/watchpat-reimbursement/)
* [ EndoPAT®️ Reimbursement ](https://www.itamar-medical.com/reimbursement/)
* [ WatchPAT®️ Software & Firmware Upgrades ](https://www.itamar-medical.com/support/upgrades-installation/)
* [ Customer Questionnaire ](https://www.itamar-medical.com/?page_id=1573)
* [ Product Bulletins ](https://www.itamar-medical.com/support/announcements-2/)
* [ Legal and Terms and Conditions ](https://www.itamar-medical.com/terms-and-conditions/)
* Healthcare professionals
* Sleep Medicine
* [ CARDIO SLEEP PUBLICATIONS ](https://www.itamar-medical.com/professionals/publications/)
* [ Blog ](https://www.itamar-medical.com/blog-2/)
* [ Videos ](https://www.itamar-medical.com/professionals/videos/)
* [ Webinars ](https://www.itamar-medical.com/sleepmedicine-webinars/)
* Cardiology
* [ WatchPAT®️ Solutions ](https://www.itamar-medical.com/cardiology/watchpat-solutions/)
* [ Cardio Sleep Clinical Testimonials ](https://www.itamar-medical.com/professionals/clinical-testimonials/)
* [ Cardio Sleep Blog ](https://www.itamar-medical.com/?page_id=9340)
* [ CARDIO SLEEP PUBLICATIONS ](https://www.itamar-medical.com/professionals/publications/)
* [ SLEEP APNEA AND CARDIOLOGY: Clinical Research ](https://www.itamar-medical.com/clinical-research/)
* Dental
* [ Dental Blog ](https://www.itamar-medical.com/?page_id=10826)
* Info & Resources
* [ CARDIO SLEEP PUBLICATIONS ](https://www.itamar-medical.com/professionals/publications/)
* [ SLEEP APNEA BLOG ](https://www.itamar-medical.com/blog-2/)
* [ Videos ](https://www.itamar-medical.com/professionals/videos/)
* International
* [ Spanish ](https://es.itamar-medical.com/)
* [ French ](https://www.watchpat.fr/)
* About Us
* [ Company Profile ](https://www.itamar-medical.com/company-profile/)
* [ Global Presence ](https://www.itamar-medical.com/global-presence/)
* [ WatchPAT® ONE Green Program ](https://www.itamar-medical.com/greenprogram/)
* [ ZOLL Itamar Corporate News ](https://www.itamar-medical.com/news-media/)
* [ Contact ](https://www.itamar-medical.com/contact-us/)
* [ Patients ](https://www.itamar-medical.com/patients/)
* Get Educated
* [ What is sleep apnea ](https://www.itamar-medical.com/patients/facts-what-is-sleep-apnea/)
* [ Cardiovascular Disease and Sleep Apnea ](https://www.itamar-medical.com/patients/cardiovascular-patients/)
* [ Sleep Apnea Risk Level Test ](https://www.itamar-medical.com/patients/sleep-apnea-test/)
* Test at Home
* [ Watchpat – Home Sleep Testing ](https://www.itamar-medical.com/patients/watchpat-home-sleep-testing/)
* [ How to Use ](https://www.itamar-medical.com/support/tutorial-videos/)
* [ Find a Physician ](https://www.itamar-medical.com/find-a-physician/)
* [ WatchPAT® ONE Green Program ](https://www.itamar-medical.com/greenprogram/)
Accessibility Toolbar
_close_ Toggle the visibility of the Accessibility Toolbar
_keyboard_ Keyboard Navigation
_visibility_off_ Disable Animations
_nights_stay_ Contrast
_format_size_ Increase Text
_text_fields_ Decrease Text
_font_download_ Readable Font
_title_ Mark Titles
_link_ Highlight Links & Buttons
* Powered with _favorite_ Love by [ Codenroll ](https://www.codenroll.co.il/)
| biology | 387275 | https://nn.wikipedia.org/wiki/Podocarpaceae | Podocarpaceae | Podocarpaceae, på norsk også kjend som gultrefamilien eller podokarpfamilien, er ein biologisk familie av bartre. Trea i familien veks hovudsakleg på den sørlege halvkula. Han omfattar 170-200 nolevande artar fordelt på 17-19 slekter. Familien er utprega sørleg med sentrum i blant anna Ny-Caledonia, Tasmania, New Zealand, Søraust-Asia og Sør-Amerika. Slektene Podocarpus og den endemiske Afrocarpus finst òg i det sørlege Afrika. Podocarpus-artar òg finst så langt nord som sørlege Japan og Kina i Asia og Mexico i Amerika, medan Nageia finst i Sør-Kina og Sør-India.
Arten Parasitaxus usta er unik som det einaste parasittiske bartreet i verda. Det er parasittisk på eit anna medlem av gultrefamilien, nemleg Falcatifolium taxoides på Ny-Caledonia.
Slekta Phyllocladus, som gjerne blir rekna til familien, blir av enkelte forskarar plassert som ein eigen familie – Phyllocladaceae.
Taksonomi
Acmopyle, 2 artar
Acmopyle pancheri (Ny-Caledonia)
Acmopyle sahniana (Fiji)
Afrocarpus, 6 artar
Afrocarpus dawei (Kenya, Tanzania, Uganda, Kongo)
Afrocarpus falcatus (Sør-Afrika, Mosambik)
Afrocarpus gaussenii (Madagaskar)
Afrocarpus gracilior (Etiopia, Kenya, Uganda, Tanzania)
Afrocarpus mannii (São Tomé)
Afrocarpus usambarensis (Burundi, Rwanda, Kongo, Tanzania)
Dacrycarpus, 9 artar
Dacrycarpus cinctus (Ny-Guinea)
Dacrycarpus compactus (Ny-Guinea)
Dacrycarpus cumingii (Indonesia, Malaysia, Filippinane)
Dacrycarpus dacrydioides (New Zealand), kahikatea
Dacrycarpus expansus (Ny-Guinea)
Dacrycarpus imbricatus (Kina, Søraust-Asia, Indonesia, Ny-Guinea, Filippinene, Fiji, Vanuatu)
Dacrycarpus kinabaluensis (Malaysia)
Dacrycarpus steupii (Indonesia)
Dacrycarpus vieillardii (Ny-Caledonia)
Dacrydium, 16-19 artar
Dacrydium balansae (Ny-Caledonia)
Dacrydium beccarii (Indonesia, Malaysia, Ny-Guinea, Filippinane, Salomonøyane)
Dacrydium comosum (Malaysia)
Dacrydium cupressinum eller «Rimu» (New Zealand)
Dacrydium cornwalliana (Indonesia, Ny-Guinea)
Dacrydium elatum (Kina, Søraust-Asia, Malaysia, Indonesia)
Dacrydium gibbsiae (Mt. Kinabalu, Malaysia)
Dacrydium guillauminii (Ny-Caledonia)
Dacrydium leptophyllum (Indonesia)
Dacrydium magnum (Indonesia, Ny-Guinea)
Dacrydium medium (Indonesia, Malaysia)
Dacrydium nidulum (Indonesia, Ny-Guinea, Fiji)
Dacrydium novo-guineense (Indonesia, Ny-Guinea)
Dacrydium pectinatum (Kina, Borneo, Malaysia, Filippinane)
Dacrydium spathoides (Indonesia)
Dacrydium xanthandrum (Indonesia, Borneo, Malaysia, Filippinane)
Falcatifolium, 5 artar
Falcatifolium angustum (Malaysia)
Falcatifolium falciforme (Borneo)
Falcatifolium gruezoi
Falcatifolium papuanum (Ny-Guinea)
Falcatifolium sleumeri (Indonesia)
Falcatifolium taxoides (Ny-Caledonia)
Halocarpus, 3 artar
Halocarpus bidwillii (New Zealand)
Halocarpus biformis (New Zealand)
Halocarpus kirkii eller «Maonao» (New Zealand)
Lagarostrobos, 1 art
Lagarostrobos franklinii (Tasmania)
Lepidothamnus, 3 artar
Lepidothamnus fonkii (Chile, Argentina)
Lepidothamnus intermedius (New Zealand)
Lepidothamnus laxifolius (New Zealand)
Manoao, 1 art
Manoao colensoi eller «Silver pine» (New Zealand)
Microcachrys, 1 art
Microcachrys tetragona (Tasmania)
Microstrobos
Nageia
Parasitaxus
Parasitaxus usta (Ny-Caledonia)
Phyllocladus
Podocarpus
Podocarpus totara, tōtara
Prumnopitys
Chilensk plommebarlind eller «Chilean Plum Yew» (Prumnopitys andina) = syn. Podocarpus andinus - Chile
Matai eller «plommebarlind» (Prumnopitys taxifolia) – New Zealand
Miro (Prumnopitys ferruginea) – New Zealand
Retrophyllum
Saxegothaea
Prins Albert-barlind «Prince Albert's Yew» (Saxegothaea conspicua) – (Sør-Amerika)
Sundacarpus
Kjelder
Denne artikkelen bygger på «Gultrefamilien» frå , den 2. februar 2021.
Plantefamiliar | norwegian_nynorsk | 1.131987 |
baby_animals_cellulose/Cecotrope.txt | Cecotropes (also caecotropes, cecotrophs, cecal pellets, soft feces, or night feces) are a nutrient filled package created in the gastointestinal (GI) tract, expelled and eaten by rabbits and guinea pigs (among other animals) to get more nutrition out of their food. The first time through the GI tract, small particles of fiber are moved into the cecum (at the small intestine/colon junction), where microbes ferment them. This creates useable nutrients which are stored and expelled in cecotropes. The cecotropes are eaten and the nutrients are absorbed in the small intestine.
Terminology[edit]
Cecotropes are not fecal material but rather nutrition, so terms such as "soft feces" and "night feces" are technically incorrect.
Similarly, though cecotropes are sometimes called "night feces," they are in fact produced throughout the day and night.
The act of eating cecotropes is known as cecotrophy (caecotrophy, cecophagy, pseudo-rumination, refection), again as distinct from coprophagy (the eating of feces proper).
Rabbits (and other animals discussed here) will occasionally engage in coprophagy.
Cecotropes are a group of small balls clumped together that look like a thin blackberry, which exit the anus all at once. They are very dark (almost black) and smelly, look wet, are sticky (as they are covered in mucus), are very soft, and are full of nutrition.
Cecotropes differ from regular feces (dry feces, hard feces, or fecal pellets), which are larger, single balls, exit the anus one at a time, are dark brown/dark gray, smell only slightly, have very little moisture, are harder and are a waste product.
It is well known that lagomorphs (rabbits, hares, pikas) eat cecotropes. Some rodents do the same, including the beaver and probably all in the suborder Hystricomorpha (e.g., capybara, guinea pig, chinchilla).
Other animals also eat cecotropes, for example marsupials (common ringtail possum, coppery ringtail possum).
While the information in this article is specific to rabbits, much of the information also relates to all animals that eat cecotropes.
These animals are hindgut fermenters. This means fibrous food material is fermented after the small intestine (in the cecum and/or colon). Small animals (discussed in this article) are classified as cecal fermenters while large animals are colonic fermenters.
They all have one stomach (monogastric).
Not all hindgut fermentators have ceca that make material for cecotropes that are reingested.
Overview[edit]
The stomach and small intestine digest food material. The small intestine also absorbs some digested material. The rest of the material then moves into the colon. Here material is separated according to size. The large particles continue to move down the colon while the small particles move back up the colon and into the cecum. The large particles are formed into regular feces and expelled. Meanwhile, the material in the cecum is fermented by microbes, producing nutrients that can later be absorbed. The material is then passed down the colon, formed into cecotropes, expelled and eaten. When the cecotropes move into the small intestine, the nutrients are absorbed.
Before the cecum[edit]
Animals discussed in this article are herbivores.
Adults eat more than 30 meals a day.
The incisors cut the food (e.g., grass and forbs) while the premolars and molars grind it into smaller pieces. The organized tongue movements help to thoroughly chew the food.
Saliva (containing the enzyme amylase) starts the digestion process.
The food material is swallowed down the esophagus and then reaches the stomach, where digestion continues. The stomach is 15% of the total volume of the GI tract and has a pH of 1-2 (which is very acidic).
Rabbits cannot vomit. This is because where the esophagus meets the stomach, rabbits have a massive muscular sphincter (with both smooth and striated muscles) along with a mucosal membrane flap that produces a watertight one-way seal.
They also lack the nerves necessary to vomit.
Moving down to the small intestine (12% of GI tract),
digestion continues. Most absorption occurs in the small intestine, where the nutrients move through the walls and into the bloodstream.
Some absorption also occurs in the stomach, cecum and colon.
The material then reaches the proximal (upper) colon. Between the proximal and distal (lower) colon is a small segment called the fusus coli, which is unique to lagomorphs. It regulates the separation of the material. Particles greater than 0.3-0.5 mm (mainly non-fermentable material) move to the center of the colon and then peristalsis moves them down the colon. Particles less than 0.3-0.5 mm (mainly fermentable fiber and proteins) move to the sides, and then retrograde peristalsis moves them back up the colon and into the cecum.
The ileocecal valve (at the end of the small intestine) ensures the material goes to the cecum and not the small intestine.
At the cecum[edit]
A rabbit's cecum is proportionally the largest of any mammal. It is 40% of the total volume of the GI tract.
The cecum is a blind sac coming off the small intestine/colon junction. At the end of the cecum is the vermiform appendix.
Mammalian enzymes cannot break down fiber.
However, microbes in the cecum have enzymes that are capable of breaking down fiber.
The microbes include bacteria (mainly Bacteroides and also Bifidobacterium, Clostridium, Streptococcus, Enterobacter, Endophorus, Acuformis, Peptococcus,
Peptostreptococcus, Fusobacterium, Coliform (usually in small numbers, e.g., Escherischia coli) and others), protozoa (ciliated and flagellated), an amoeboid organism (Entamoeba cuniculi) and a rabbit-specific yeast (Cyniclomyces guttulatulus).
It is estimated that more than 50% of the microbes are not known.
Note that no Lactobacillus species are found in the microbiome of the rabbit and thus using L. acidophilus as a probiotic has unknown value.
The anaerobic fermentation in the cecum breaks down the fiber into useable food for the animal. It is also used as food for the proliferating microbes. The results of the fermentation are volatile fatty acids (VFAs) (mostly acetic, butyric and propionic acids), all of the B vitamins, vitamin K, microbial proteins, essential amino acids and minerals.
The cecum has a pH of 5.4-6.8, which does not harm the microbes.
Most of the VFAs are absorbed through the walls of the cecum.
Some of the other nutrients are also absorbed by the cecum and the colon.
Four to nine hours after a meal, the cecum empties and the contents (containing the results of fermentation, along with microbes) continue down the colon.
After the cecum[edit]
Microbes also live in the colon.
Cecotropes and regular feces pass through the colon at different times. Regular feces are formed in the fusus coli, continue through the colon and rectum and are expelled through the anus, about 4 hours after eating.
They contain mainly insoluble fiber which is used for motility, not for nutrition.
The material from the cecum is formed into cecotropes in the fusus coli, where it contracts more gently than when forming regular feces.
Goblet cells in the fusus coli secrete mucus which covers the cecotropes, which will protect them when they get into the acidic stomach.
An enzyme (lysozyme) is also added that aids digestion of microbial proteins.
Cecotropes (pH about 7) continue through the colon and rectum and are expelled thru the anus, about eight hours after eating.
Reingestion[edit]
Cecotropes are eaten directly from the anus.
They usually do not touch the ground. They are not chewed (even though it looks like it).
They are swallowed whole so the mucus is not disturbed. They are held in the fundic region of the stomach (at the top) for 3 to 6 hours where they continue to ferment.
Then they move into the small intestine
where the nutrients are absorbed,
about 17 hours after the original meal.
The gastrointestinal tract of newborn rabbits is sterile and contains no microbes. The babies eat cecotropes and regular feces from the mother in order to obtain microbes that are needed for the cecum. Young rabbits start eating their own cecotropes at about day 20.
The stomach of the babies has a pH of 5 to 6.5, which does not kill the microbes. However, when the mother's milk combines with an enzyme in the baby's stomach, it produces an antimicrobial fatty acid (octanoic and decanoic acids) (milk oil) which kills microbes.
Only after the milk oil decreases and before the stomach pH gets too low (as the baby ages) can the microbes survive the stomach conditions and pass into the cecum to proliferate.
Why cecotrophy[edit]
Many herbivores have a diet that is low in nutrition and high in fiber (which is a non-starch polysaccharide carbohydrate).
Fiber can be either soluble (pectins and gums) or insoluble (cellulose, hemicellulose and lignocellulose).
A simple gastrointestinal tract is not capable of extracting enough nutrients for these animals.
One strategy to get the needed nutrition is used by ruminants (e.g., cows). They chew the cud in order to process their food a second time to extract more nutrients.
Another strategy (e.g., used by horses) is to have a very long colon to aid in digestion and absorption.
Both of these strategies add substantial bulk to the animal.
Since the rabbit is at the bottom of the food chain, it must be nimble in order to out run its many predators. Creating cecotropes is a way to get more nutrients out of their food without adding a lot of bulk to their GI tract (which is 10% - 20% of their body weight).
Since their colons do not absorb the nutrients in the cecotropes, they reingest them so they can be absorbed in the small intestine.
Disorder[edit]
It is essential to maintain a balanced microbiome in the gastrointestinal tract, especially the cecum. If beneficial microbes decrease and harmful microbes proliferate, the microbiome becomes unbalanced (called dysbiosis).
The cause of this includes a diet too high in carbohydrates and/or too low in indigestible fiber (which slows down gut motility and changes the pH of the cecum, among other things); toxins; some medications (especially some antibiotics); dehydration; extreme stress; dental disease and other systemic diseases (e.g., liver or kidney disease). If the balance is not maintained, there can be multiple health issues, including GI stasis, which can lead to pain, stress and death.
A few cecotropes left on the ground of the living area of the animal is not cause for concern. However, if a large amount is found on the ground or stuck to the fur, a veterinarian should be consulted. Possible causes are poor diet, dental issues, arthritis, very large dewlap, obesity, or too-long fur in the anal region.
If the cecotropes are like pudding, it is called intermittent soft cecotropes (ISC). This is different from true diarrhea, which has no form, is completely watery and is very serious. If regular feces are also produced, it is not diarrhea.
ISC will stick to the hindquarters and feet of the animal and to places in the living area. Causes are a poor diet (too many carbohydrates, too little fiber) or inappropriate antibiotics. Treatment is to feed unlimited grass hay, greens and limited pellets and to stop giving inappropriate antibiotics. | biology | 14155 | https://da.wikipedia.org/wiki/Mikroorganisme | Mikroorganisme | En mikroorganisme (mikrobe) er en organisme som er så lille, at den kun kan ses i et mikroskop.
Bakterier på arbejde
Ofte omtaler man mikroorganismer som levende enzymfabrikker, da de kan indeholde flere millioner enzymer. Man udnytter dog også mikroorganismer i industrien; i den industrielle sammenhæng gæres mikroorgansimer i store tanke, hvor der bliver produceret enzymer, som fx bruges til gødning eller fremstilling af vaskemiddel. Derfor kan man med sikkerhed sige, at enzymer anvendes i flere forskellige processer. I dag er det også muligt, at indsplejse en DNA streng så den danner de proteiner man ønsker at fremstille. Det er blandt andet den proces, der foretages, når insulin fremstilles.
Ved rensning af vand hjælper bakterier også med at rense fx industrispildevand. Populært sagt siger vi, at mikroorgansimerne æder affaldet og omdanner det til kuldioxid, vand og salte. Med tiden indgår disse elementer igen i naturens økologiske kredsløb.
Bakterier i kvælstofskredsløbet
Knoldbakterier binder stoffet nitrogen, og med denne proces skaber de dermed det primære grundlag for, at planter kan overleve i naturen. En anden vigtig funktion opstår under processen: forrådnelse. Når dødt organisk materiale bliver nedbrudt, bliver der dannet ammoniak. Når dette stof kommer i kontakt med vand, dannes der et ammoniumion. Dette ammoniumion bliver omdannet til nitritioner ved hjælp af effektive nitritbakterier. Derefter omdanner nitrat nitritioner til nitrationer. De mange kemiske reaktioner resulterer i det vi kalder nitrifikationsprocessen.
Denne proces medfører, at planter kan få de næringstoffer, som de har brug for til deres overlevelse. Alligevel kan visse problemer opstå; hvis planter modtager mere næring, end de kan optage, kan næringen blive udnyttet af alger. Formerer algerne sig, medfører det, at underhavsplanter ikke kan få det nødvendige sollys til deres fotosyntese. I stedet foretager disse planter respiration. Dette vil resultere i iltsvind, der medfører fiske- og plantedød. Ved nebrydelsen af disse forsvinder endnu mere ilt.
Følgende organismegrupper indeholder arter som er mikroorganismer:
bjørnedyr
amøbe
protozo
alge
rødalge
brunalge
grønalge
plankton
svampedyr
eubacteria
arker
stramenopila
Vira
Gærsvampe
Parasitter
Se også
liv i rummet
Eksterne henvisninger
Mikroorganismer. Biotech Academy
3.12.2003, Ing.dk: Bakterier skal afvises – ikke dræbes Modermælk og tranebærsaft indeholder stoffer, der forhindrer bakterier i at binde sig til kroppens slimhinder. Citat: "...Mikroberne har haft millioner af år til at udvikle resistens overfor denne teknik, der »trækker tæppet bort under dem«, men det er ikke lykkedes..."
BBC News, 28 September, 2001: The microbes that 'rule the world' Citat: "... The Earth's climate may be dependent upon microbes that eat rock beneath the sea floor, according to new research....The number of the worm-like tracks in the rocks diminishes with depth; at 300 metres (985 feet) below the sea floor, they become much rarer..."
BBC News, 14 October, 2002, Earth 'depends on creepy-crawlies'
BBC News, 10 July, 2000, Snow microbes found at South Pole Citat: "...able to survive the large doses of ultraviolet radiation, extreme cold and darkness...The microbes have DNA sequences similar to a category of bacteria known as Deinococcus..."
BBCNews: 16 January, 2002, Tough bugs point to life on Mars Citat: "...This research demonstrates that certain microbes can thrive in the absence of sunlight by using hydrogen gas..."
Ingeniøren: 14.04.2002 Brint-spisende bakterier fundet under jorden Nye undersøgelser viser, at der findes enorme mængder bakterier under jorden, der lever af brint.
BBCNews: 17 January, 2002, Alien life could be like Antarctic bugs
31 January, 2004, BBC News: Microbes 'are living antibiotic' Citat: "...Once it has collided with a potential prey cell, it attaches itself to it, pulling itself close using long retractable fibres...It can then produce chemicals which can cut a hole in the cell wall, pull itself in and start consuming the cell from the inside..."
01.02.2004, Ing.dk: Dresserede bakterier gør underlivet surt Svensk hygiejnegigant satser på intelligente trusseindlæg. Citat: "...hvorefter de først vågner op, når kvinden tager trusseindlægget på. Herefter bevæger de sig over på huden og begynder at arbejde..." | danish | 0.538748 |
humans_more_adapted_to_light_mode_or_dark_mode/Light.txt |
Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 terahertz, between the infrared (with longer wavelengths) and the ultraviolet (with shorter wavelengths).
In physics, the term "light" may refer more broadly to electromagnetic radiation of any wavelength, whether visible or not. In this sense, gamma rays, X-rays, microwaves and radio waves are also light. The primary properties of light are intensity, propagation direction, frequency or wavelength spectrum, and polarization. Its speed in vacuum, 299792458 m/s, is one of the fundamental constants of nature. Like all types of electromagnetic radiation, visible light propagates by massless elementary particles called photons that represents the quanta of electromagnetic field, and can be analyzed as both waves and particles. The study of light, known as optics, is an important research area in modern physics.
The main source of natural light on Earth is the Sun. Historically, another important source of light for humans has been fire, from ancient campfires to modern kerosene lamps. With the development of electric lights and power systems, electric lighting has effectively replaced firelight.
Electromagnetic spectrum and visible light
The electromagnetic spectrum, with the visible portion highlighted. The bottom graph (Visible spectrum) is wavelength in units of nanometres (nm).
Main article: Electromagnetic spectrum
Generally, electromagnetic radiation (EMR) is classified by wavelength into radio waves, microwaves, infrared, the visible spectrum that we perceive as light, ultraviolet, X-rays and gamma rays. The designation "radiation" excludes static electric, magnetic and near fields.
The behavior of EMR depends on its wavelength. Higher frequencies have shorter wavelengths and lower frequencies have longer wavelengths. When EMR interacts with single atoms and molecules, its behavior depends on the amount of energy per quantum it carries.
EMR in the visible light region consists of quanta (called photons) that are at the lower end of the energies that are capable of causing electronic excitation within molecules, which leads to changes in the bonding or chemistry of the molecule. At the lower end of the visible light spectrum, EMR becomes invisible to humans (infrared) because its photons no longer have enough individual energy to cause a lasting molecular change (a change in conformation) in the visual molecule retinal in the human retina, which change triggers the sensation of vision.
There exist animals that are sensitive to various types of infrared, but not by means of quantum-absorption. Infrared sensing in snakes depends on a kind of natural thermal imaging, in which tiny packets of cellular water are raised in temperature by the infrared radiation. EMR in this range causes molecular vibration and heating effects, which is how these animals detect it.
Above the range of visible light, ultraviolet light becomes invisible to humans, mostly because it is absorbed by the cornea below 360 nm and the internal lens below 400 nm. Furthermore, the rods and cones located in the retina of the human eye cannot detect the very short (below 360 nm) ultraviolet wavelengths and are in fact damaged by ultraviolet. Many animals with eyes that do not require lenses (such as insects and shrimp) are able to detect ultraviolet, by quantum photon-absorption mechanisms, in much the same chemical way that humans detect visible light.
Various sources define visible light as narrowly as 420–680 nm to as broadly as 380–800 nm. Under ideal laboratory conditions, people can see infrared up to at least 1,050 nm; children and young adults may perceive ultraviolet wavelengths down to about 310–313 nm.
Plant growth is also affected by the colour spectrum of light, a process known as photomorphogenesis.
Speed of light
Main article: Speed of light
Beam of sun light inside the cavity of Rocca ill'Abissu at Fondachelli-Fantina, Sicily
The speed of light in vacuum is defined to be exactly 299 792 458 m/s (approx. 186,282 miles per second). The fixed value of the speed of light in SI units results from the fact that the metre is now defined in terms of the speed of light. All forms of electromagnetic radiation move at exactly this same speed in vacuum.
Different physicists have attempted to measure the speed of light throughout history. Galileo attempted to measure the speed of light in the seventeenth century. An early experiment to measure the speed of light was conducted by Ole Rømer, a Danish physicist, in 1676. Using a telescope, Rømer observed the motions of Jupiter and one of its moons, Io. Noting discrepancies in the apparent period of Io's orbit, he calculated that light takes about 22 minutes to traverse the diameter of Earth's orbit. However, its size was not known at that time. If Rømer had known the diameter of the Earth's orbit, he would have calculated a speed of 227000000 m/s.
Another more accurate measurement of the speed of light was performed in Europe by Hippolyte Fizeau in 1849. Fizeau directed a beam of light at a mirror several kilometers away. A rotating cog wheel was placed in the path of the light beam as it traveled from the source, to the mirror and then returned to its origin. Fizeau found that at a certain rate of rotation, the beam would pass through one gap in the wheel on the way out and the next gap on the way back. Knowing the distance to the mirror, the number of teeth on the wheel and the rate of rotation, Fizeau was able to calculate the speed of light as 313000000 m/s.
Léon Foucault carried out an experiment which used rotating mirrors to obtain a value of 298 000 000 m/s in 1862. Albert A. Michelson conducted experiments on the speed of light from 1877 until his death in 1931. He refined Foucault's methods in 1926 using improved rotating mirrors to measure the time it took light to make a round trip from Mount Wilson to Mount San Antonio in California. The precise measurements yielded a speed of 299 796 000 m/s.
The effective velocity of light in various transparent substances containing ordinary matter, is less than in vacuum. For example, the speed of light in water is about 3/4 of that in vacuum.
Two independent teams of physicists were said to bring light to a "complete standstill" by passing it through a Bose–Einstein condensate of the element rubidium, one team at Harvard University and the Rowland Institute for Science in Cambridge, Massachusetts and the other at the Harvard–Smithsonian Center for Astrophysics, also in Cambridge. However, the popular description of light being "stopped" in these experiments refers only to light being stored in the excited states of atoms, then re-emitted at an arbitrary later time, as stimulated by a second laser pulse. During the time it had "stopped", it had ceased to be light.
Optics
Main article: Optics
The study of light and the interaction of light and matter is termed optics. The observation and study of optical phenomena such as rainbows and the aurora borealis offer many clues as to the nature of light.
A transparent object allows light to transmit or pass through. Conversely, an opaque object does not allow light to transmit through and instead reflecting or absorbing the light it receives. Most objects do not reflect or transmit light specularly and to some degree scatters the incoming light, which is called glossiness. Surface scatterance is caused by the surface roughness of the reflecting surfaces, and internal scatterance is caused by the difference of refractive index between the particles and medium inside the object. Like transparent objects, translucent objects allow light to transmit through, but translucent objects also scatter certain wavelength of light via internal scatterance.
Refraction
Main article: Refraction
Due to refraction, the straw dipped in water appears bent and the ruler scale compressed when viewed from a shallow angle.
Refraction is the bending of light rays when passing through a surface between one transparent material and another. It is described by Snell's Law:
n
1
sin
θ
1
=
n
2
sin
θ
2
.
{\displaystyle n_{1}\sin \theta _{1}=n_{2}\sin \theta _{2}\ .}
where θ1 is the angle between the ray and the surface normal in the first medium, θ2 is the angle between the ray and the surface normal in the second medium and n1 and n2 are the indices of refraction, n = 1 in a vacuum and n > 1 in a transparent substance.
When a beam of light crosses the boundary between a vacuum and another medium, or between two different media, the wavelength of the light changes, but the frequency remains constant. If the beam of light is not orthogonal (or rather normal) to the boundary, the change in wavelength results in a change in the direction of the beam. This change of direction is known as refraction.
The refractive quality of lenses is frequently used to manipulate light in order to change the apparent size of images. Magnifying glasses, spectacles, contact lenses, microscopes and refracting telescopes are all examples of this manipulation.
Light sources
"Lightsource" redirects here. For the solar energy developer named Lightsource, see Lightsource Renewable Energy. For a particle accelerator used to generate X-rays, see Synchrotron light source.
Further information: List of light sources
There are many sources of light. A body at a given temperature emits a characteristic spectrum of black-body radiation. A simple thermal source is sunlight, the radiation emitted by the chromosphere of the Sun at around 6,000 K (5,730 °C; 10,340 °F). Solar radiation peaks in the visible region of the electromagnetic spectrum when plotted in wavelength units, and roughly 44% of the radiation that reaches the ground is visible. Another example is incandescent light bulbs, which emit only around 10% of their energy as visible light and the remainder as infrared. A common thermal light source in history is the glowing solid particles in flames, but these also emit most of their radiation in the infrared and only a fraction in the visible spectrum.
The peak of the black-body spectrum is in the deep infrared, at about 10 micrometre wavelength, for relatively cool objects like human beings. As the temperature increases, the peak shifts to shorter wavelengths, producing first a red glow, then a white one and finally a blue-white colour as the peak moves out of the visible part of the spectrum and into the ultraviolet. These colours can be seen when metal is heated to "red hot" or "white hot". Blue-white thermal emission is not often seen, except in stars (the commonly seen pure-blue colour in a gas flame or a welder's torch is in fact due to molecular emission, notably by CH radicals emitting a wavelength band around 425 nm and is not seen in stars or pure thermal radiation).
Atoms emit and absorb light at characteristic energies. This produces "emission lines" in the spectrum of each atom. Emission can be spontaneous, as in light-emitting diodes, gas discharge lamps (such as neon lamps and neon signs, mercury-vapor lamps, etc.) and flames (light from the hot gas itself—so, for example, sodium in a gas flame emits characteristic yellow light). Emission can also be stimulated, as in a laser or a microwave maser.
Deceleration of a free charged particle, such as an electron, can produce visible radiation: cyclotron radiation, synchrotron radiation and bremsstrahlung radiation are all examples of this. Particles moving through a medium faster than the speed of light in that medium can produce visible Cherenkov radiation. Certain chemicals produce visible radiation by chemoluminescence. In living things, this process is called bioluminescence. For example, fireflies produce light by this means and boats moving through water can disturb plankton which produce a glowing wake.
Certain substances produce light when they are illuminated by more energetic radiation, a process known as fluorescence. Some substances emit light slowly after excitation by more energetic radiation. This is known as phosphorescence. Phosphorescent materials can also be excited by bombarding them with subatomic particles. Cathodoluminescence is one example. This mechanism is used in cathode-ray tube television sets and computer monitors.
Hong Kong illuminated by colourful artificial lighting
Certain other mechanisms can produce light:
Bioluminescence
Cherenkov radiation
Electroluminescence
Scintillation
Sonoluminescence
Triboluminescence
When the concept of light is intended to include very-high-energy photons (gamma rays), additional generation mechanisms include:
Particle–antiparticle annihilation
Radioactive decay
Measurement
Main articles: Photometry (optics) and Radiometry
Light is measured with two main alternative sets of units: radiometry consists of measurements of light power at all wavelengths, while photometry measures light with wavelength weighted with respect to a standardized model of human brightness perception. Photometry is useful, for example, to quantify Illumination (lighting) intended for human use.
The photometry units are different from most systems of physical units in that they take into account how the human eye responds to light. The cone cells in the human eye are of three types which respond differently across the visible spectrum and the cumulative response peaks at a wavelength of around 555 nm. Therefore, two sources of light which produce the same intensity (W/m) of visible light do not necessarily appear equally bright. The photometry units are designed to take this into account and therefore are a better representation of how "bright" a light appears to be than raw intensity. They relate to raw power by a quantity called luminous efficacy and are used for purposes like determining how to best achieve sufficient illumination for various tasks in indoor and outdoor settings. The illumination measured by a photocell sensor does not necessarily correspond to what is perceived by the human eye and without filters which may be costly, photocells and charge-coupled devices (CCD) tend to respond to some infrared, ultraviolet or both.
Light pressure
Main article: Radiation pressure
Light exerts physical pressure on objects in its path, a phenomenon which can be deduced by Maxwell's equations, but can be more easily explained by the particle nature of light: photons strike and transfer their momentum. Light pressure is equal to the power of the light beam divided by c, the speed of light. Due to the magnitude of c, the effect of light pressure is negligible for everyday objects. For example, a one-milliwatt laser pointer exerts a force of about 3.3 piconewtons on the object being illuminated; thus, one could lift a U.S. penny with laser pointers, but doing so would require about 30 billion 1-mW laser pointers. However, in nanometre-scale applications such as nanoelectromechanical systems (NEMS), the effect of light pressure is more significant and exploiting light pressure to drive NEMS mechanisms and to flip nanometre-scale physical switches in integrated circuits is an active area of research. At larger scales, light pressure can cause asteroids to spin faster, acting on their irregular shapes as on the vanes of a windmill. The possibility of making solar sails that would accelerate spaceships in space is also under investigation.
Although the motion of the Crookes radiometer was originally attributed to light pressure, this interpretation is incorrect; the characteristic Crookes rotation is the result of a partial vacuum. This should not be confused with the Nichols radiometer, in which the (slight) motion caused by torque (though not enough for full rotation against friction) is directly caused by light pressure.
As a consequence of light pressure, Einstein in 1909 predicted the existence of "radiation friction" which would oppose the movement of matter. He wrote, "radiation will exert pressure on both sides of the plate. The forces of pressure exerted on the two sides are equal if the plate is at rest. However, if it is in motion, more radiation will be reflected on the surface that is ahead during the motion (front surface) than on the back surface. The backwardacting force of pressure exerted on the front surface is thus larger than the force of pressure acting on the back. Hence, as the resultant of the two forces, there remains a force that counteracts the motion of the plate and that increases with the velocity of the plate. We will call this resultant 'radiation friction' in brief."
Usually light momentum is aligned with its direction of motion. However, for example in evanescent waves momentum is transverse to direction of propagation.
Historical theories about light, in chronological order
Classical Greece and Hellenism
In the fifth century BC, Empedocles postulated that everything was composed of four elements; fire, air, earth and water. He believed that Aphrodite made the human eye out of the four elements and that she lit the fire in the eye which shone out from the eye making sight possible. If this were true, then one could see during the night just as well as during the day, so Empedocles postulated an interaction between rays from the eyes and rays from a source such as the sun.
In about 300 BC, Euclid wrote Optica, in which he studied the properties of light. Euclid postulated that light travelled in straight lines and he described the laws of reflection and studied them mathematically. He questioned that sight is the result of a beam from the eye, for he asks how one sees the stars immediately, if one closes one's eyes, then opens them at night. If the beam from the eye travels infinitely fast this is not a problem.
In 55 BC, Lucretius, a Roman who carried on the ideas of earlier Greek atomists, wrote that "The light & heat of the sun; these are composed of minute atoms which, when they are shoved off, lose no time in shooting right across the interspace of air in the direction imparted by the shove." (from On the nature of the Universe). Despite being similar to later particle theories, Lucretius's views were not generally accepted. Ptolemy (c. second century) wrote about the refraction of light in his book Optics.
Classical India
In ancient India, the Hindu schools of Samkhya and Vaisheshika, from around the early centuries AD developed theories on light. According to the Samkhya school, light is one of the five fundamental "subtle" elements (tanmatra) out of which emerge the gross elements. The atomicity of these elements is not specifically mentioned and it appears that they were actually taken to be continuous.
The Vishnu Purana refers to sunlight as "the seven rays of the sun".
The Indian Buddhists, such as Dignāga in the fifth century and Dharmakirti in the seventh century, developed a type of atomism that is a philosophy about reality being composed of atomic entities that are momentary flashes of light or energy. They viewed light as being an atomic entity equivalent to energy.
Descartes
René Descartes (1596–1650) held that light was a mechanical property of the luminous body, rejecting the "forms" of Ibn al-Haytham and Witelo as well as the "species" of Bacon, Grosseteste and Kepler. In 1637 he published a theory of the refraction of light that assumed, incorrectly, that light travelled faster in a denser medium than in a less dense medium. Descartes arrived at this conclusion by analogy with the behaviour of sound waves. Although Descartes was incorrect about the relative speeds, he was correct in assuming that light behaved like a wave and in concluding that refraction could be explained by the speed of light in different media.
Descartes is not the first to use the mechanical analogies but because he clearly asserts that light is only a mechanical property of the luminous body and the transmitting medium, Descartes's theory of light is regarded as the start of modern physical optics.
Particle theory
Main article: Corpuscular theory of light
Pierre Gassendi
Pierre Gassendi (1592–1655), an atomist, proposed a particle theory of light which was published posthumously in the 1660s. Isaac Newton studied Gassendi's work at an early age and preferred his view to Descartes's theory of the plenum. He stated in his Hypothesis of Light of 1675 that light was composed of corpuscles (particles of matter) which were emitted in all directions from a source. One of Newton's arguments against the wave nature of light was that waves were known to bend around obstacles, while light travelled only in straight lines. He did, however, explain the phenomenon of the diffraction of light (which had been observed by Francesco Grimaldi) by allowing that a light particle could create a localised wave in the aether.
Newton's theory could be used to predict the reflection of light, but could only explain refraction by incorrectly assuming that light accelerated upon entering a denser medium because the gravitational pull was greater. Newton published the final version of his theory in his Opticks of 1704. His reputation helped the particle theory of light to hold sway during the eighteenth century. The particle theory of light led Laplace to argue that a body could be so massive that light could not escape from it. In other words, it would become what is now called a black hole. Laplace withdrew his suggestion later, after a wave theory of light became firmly established as the model for light (as has been explained, neither a particle or wave theory is fully correct). A translation of Newton's essay on light appears in The large scale structure of space-time, by Stephen Hawking and George F. R. Ellis.
The fact that light could be polarized was for the first time qualitatively explained by Newton using the particle theory. Étienne-Louis Malus in 1810 created a mathematical particle theory of polarization. Jean-Baptiste Biot in 1812 showed that this theory explained all known phenomena of light polarization. At that time the polarization was considered as the proof of the particle theory.
Wave theory
To explain the origin of colours, Robert Hooke (1635–1703) developed a "pulse theory" and compared the spreading of light to that of waves in water in his 1665 work Micrographia ("Observation IX"). In 1672 Hooke suggested that light's vibrations could be perpendicular to the direction of propagation. Christiaan Huygens (1629–1695) worked out a mathematical wave theory of light in 1678 and published it in his Treatise on Light in 1690. He proposed that light was emitted in all directions as a series of waves in a medium called the luminiferous aether. As waves are not affected by gravity, it was assumed that they slowed down upon entering a denser medium.
Christiaan Huygens
Thomas Young's sketch of a double-slit experiment showing diffraction. Young's experiments supported the theory that light consists of waves.
The wave theory predicted that light waves could interfere with each other like sound waves (as noted around 1800 by Thomas Young). Young showed by means of a diffraction experiment that light behaved as waves. He also proposed that different colours were caused by different wavelengths of light and explained colour vision in terms of three-coloured receptors in the eye. Another supporter of the wave theory was Leonhard Euler. He argued in Nova theoria lucis et colorum (1746) that diffraction could more easily be explained by a wave theory. In 1816 André-Marie Ampère gave Augustin-Jean Fresnel an idea that the polarization of light can be explained by the wave theory if light were a transverse wave.
Later, Fresnel independently worked out his own wave theory of light and presented it to the Académie des Sciences in 1817. Siméon Denis Poisson added to Fresnel's mathematical work to produce a convincing argument in favor of the wave theory, helping to overturn Newton's corpuscular theory. By the year 1821, Fresnel was able to show via mathematical methods that polarization could be explained by the wave theory of light if and only if light was entirely transverse, with no longitudinal vibration whatsoever.
The weakness of the wave theory was that light waves, like sound waves, would need a medium for transmission. The existence of the hypothetical substance luminiferous aether proposed by Huygens in 1678 was cast into strong doubt in the late nineteenth century by the Michelson–Morley experiment.
Newton's corpuscular theory implied that light would travel faster in a denser medium, while the wave theory of Huygens and others implied the opposite. At that time, the speed of light could not be measured accurately enough to decide which theory was correct. The first to make a sufficiently accurate measurement was Léon Foucault, in 1850. His result supported the wave theory and the classical particle theory was finally abandoned, only to partly re-emerge in the twentieth century.
Electromagnetic theory
Main article: Electromagnetic radiation
A linearly polarized electromagnetic wave traveling along the z-axis, with E denoting the electric field and perpendicular B denoting magnetic field
In 1845, Michael Faraday discovered that the plane of polarization of linearly polarized light is rotated when the light rays travel along the magnetic field direction in the presence of a transparent dielectric, an effect now known as Faraday rotation. This was the first evidence that light was related to electromagnetism. In 1846 he speculated that light might be some form of disturbance propagating along magnetic field lines. Faraday proposed in 1847 that light was a high-frequency electromagnetic vibration, which could propagate even in the absence of a medium such as the ether.
Faraday's work inspired James Clerk Maxwell to study electromagnetic radiation and light. Maxwell discovered that self-propagating electromagnetic waves would travel through space at a constant speed, which happened to be equal to the previously measured speed of light. From this, Maxwell concluded that light was a form of electromagnetic radiation: he first stated this result in 1862 in On Physical Lines of Force. In 1873, he published A Treatise on Electricity and Magnetism, which contained a full mathematical description of the behavior of electric and magnetic fields, still known as Maxwell's equations. Soon after, Heinrich Hertz confirmed Maxwell's theory experimentally by generating and detecting radio waves in the laboratory and demonstrating that these waves behaved exactly like visible light, exhibiting properties such as reflection, refraction, diffraction and interference. Maxwell's theory and Hertz's experiments led directly to the development of modern radio, radar, television, electromagnetic imaging and wireless communications.
In the quantum theory, photons are seen as wave packets of the waves described in the classical theory of Maxwell. The quantum theory was needed to explain effects even with visual light that Maxwell's classical theory could not (such as spectral lines).
Quantum theory
In 1900 Max Planck, attempting to explain black-body radiation, suggested that although light was a wave, these waves could gain or lose energy only in finite amounts related to their frequency. Planck called these "lumps" of light energy "quanta" (from a Latin word for "how much"). In 1905, Albert Einstein used the idea of light quanta to explain the photoelectric effect and suggested that these light quanta had a "real" existence. In 1923 Arthur Holly Compton showed that the wavelength shift seen when low intensity X-rays scattered from electrons (so called Compton scattering) could be explained by a particle-theory of X-rays, but not a wave theory. In 1926 Gilbert N. Lewis named these light quanta particles photons.
Eventually the modern theory of quantum mechanics came to picture light as (in some sense) both a particle and a wave and (in another sense), as a phenomenon which is neither a particle nor a wave (which actually are macroscopic phenomena, such as baseballs or ocean waves). Instead, modern physics sees light as something that can be described sometimes with mathematics appropriate to one type of macroscopic metaphor (particles) and sometimes another macroscopic metaphor (water waves), but is actually something that cannot be fully imagined. As in the case for radio waves and the X-rays involved in Compton scattering, physicists have noted that electromagnetic radiation tends to behave more like a classical wave at lower frequencies, but more like a classical particle at higher frequencies, but never completely loses all qualities of one or the other. Visible light, which occupies a middle ground in frequency, can easily be shown in experiments to be describable using either a wave or particle model, or sometimes both.
In February 2018, scientists reported, for the first time, the discovery of a new form of light, which may involve polaritons, that could be useful in the development of quantum computers.
Use for light on Earth
Sunlight provides the energy that green plants use to create sugars mostly in the form of starches, which release energy into the living things that digest them. This process of photosynthesis provides virtually all the energy used by living things. Some species of animals generate their own light, a process called bioluminescence. For example, fireflies use light to locate mates and vampire squid use it to hide themselves from prey.
See also
Physics portalScience portal
Automotive lighting
Ballistic photon
Colour temperature
Fermat's principle
Huygens' principle
Journal of Luminescence
Light art
Light beam – in particular about light beams visible from the side
Light Fantastic (TV series)
Light mill
Light painting
Light pollution
Light therapy
Lighting
List of light sources
Luminescence: The Journal of Biological and Chemical Luminescence
Photic sneeze reflex
Right to light
Risks and benefits of sun exposure
Spectroscopy
Notes
| biology | 19358 | https://da.wikipedia.org/wiki/Foton | Foton | Fotonen er den elementarpartikel, der er ansvarlig for elektromagnetiske fænomener, eksempelvis elektromagnetisk stråling som røntgenstråling, ultraviolet lys, synligt lys, infrarødt lys, mikrobølger og radiobølger.
Fotonen adskiller sig fra andre elementarpartikler, f.eks. elektroner eller kvarker, ved at den ikke besidder nogen hvilemasse. I vakuum bevæger den sig med lysets hastighed, c = 299.792.458 m/s eller tæt på 300.000 km/s.
Som alle kvanter besidder fotonen både bølge- og partikelegenskaber (Partikel-bølge dualitet). Bølgeegenskaberne inkluderer brydning i linser og interferens. At fotonen også besidder partikelegenskaber kommer til udtryk ved, at den kun kan vekselvirke med stof ved at overføre en kvantiseret mængde energi givet ved
hvor h er Plancks konstant og er fotonernes bølgelængde. I modsætning hertil kan en almindelig bølge overføre eller modtage vilkårlige mængder af energi.
For synligt lys er en enkelt fotons energi mellem 2,8 × 10-19 og 5 × 10-19 J eller 1,8 og 3,1 eV, en relativt lille energi, men nok til at excitere et enkelt molekyle i øjets fotoreceptorer og dermed bidrage til synssansen. Til sammenligning skal anføres at fotonenergien af UV-stråling er mellem 3.10 og 12.4 eV, tilstrækkeligt til at bryde en kemisk binding og danne radikaler.
Udover at have en energi har fotoner også en impuls og en polarisering. Eftersom fotonen følger kvantemekanikkens love, er det ofte tilfældet, at dens egenskaber ikke har veldefinerede værdier. Derimod er de beskrevet ved en sandsynlighed for at måle en bestemt polarisering, position eller impuls. Selvom en foton er i stand til at excitere et enkelt molekyle, er det f.eks. ofte ikke muligt på forhånd at bestemme hvilket molekyle, der bliver exciteret.
Fysikere benytter ofte beskrivelsen af en foton, som en partikel der bærer elektromagnetisk stråling. Indenfor teoretisk fysik kan fotonen dog også betragtes som formidler af enhver type elektromagnetisk vekselvirkning, eksempelvis magnetfelter og elektrisk frastødning/tiltrækning mellem elektrisk ladede partikler.
Fotonen som koncept, blev udviklet gradvis omkring årene 1905-1907 af Albert Einstein for at forklare eksperimentelle observationer, der ikke stemte overens med den klassiske bølgebeskrivelse af lys. Specifikt forklarede foton-modellen lysets energis afhængighed af frekvens, samt at stof og stråling kan være i termisk ligevægt. Andre fysikere forsøgte at forklare disse observationer med semiklassiske modeller, hvor lys stadig blev beskrevet ved Maxwells ligninger, men hvor de materialer der udsendte og absorberede lyset var kvantiserede. Disse modeller medvirkede til udvikling af kvantemekanikken, men yderligere forsøg underbyggede Einsteins hypotese om at lyset er kvantiseret. Lyskvanterne er fotoner.
Fotonkonceptet har ført til store fremskridt i både eksperimentel og teoretisk fysik, f.eks. lasere, Bose-Einstein-kondensat og kvantefeltteori. Ifølge standardmodellen for partikelfysik, ligger fotoner til grund for alle elektriske og magnetiske felter og er selv et produkt af kravet om, at de fysiske love har visse symmetrier for ethvert punkt i rumtiden. Fotonens indbyggede egenskaber, som f.eks ladning, spin og (fravær af) masse, er bestemt ud fra disse symmetrier.
I 2007 lykkedes det at fastholde og måle tilstedeværelsen af en mikrobølgefoton i op til et halvt sekund mellem to superledende spejle.
Se også
Elementarpartikel
Kvantemekanik
Fotonisk krystal
Orbitalt impulsmoment (bølge)
Ultraviolet lys
Referencer
Eksterne henvisninger
Webarchive backup: En lyspartikel med identitetsproblemer (humoristisk tegning)
Number 523 #2, February 1, 2001, AIP: How Light Gets Through Tiny Holes Citat: "...Now, two research collaborations independently explain the results by showing that plasmons (themselves collective objects) and the photons of light form a composite object, known as a "surface plasmon polariton."..."
'Energy-sucking' Radio Antennas, N. Tesla's Power Receiver Citat: "...The truth is quite strange...By manipulating the EM fields, we can force an electrically-small receiving antenna to behave as if it was very, VERY large...In theory a tiny loop antenna can work as well as a longwire 1/2-wave antenna which is 10KM long...The energy doesn't vanish, instead it ends up INSIDE the atom. By resonantly creating an "anti-wave", the tiny atom has "sucked energy" out of the enormously long light waves as they go by...When all is said and done, our oscillating coil has absorbed half of the incoming EM energy and re-emitted (or "scattered") the rest..."
C. F. Bohren, "How can a particle absorb more than the light incident on it?", Am J Phys, 51 #4, pp323 Apr 1983 Citat: "...A particle can indeed absorb more than the light incident on it...In the former, strong absorption is associated with excitation of surfaces plasmons; in the latter it is associated with excitation of surface phonons. In both instances, the target area a particle presents to incident light can be much greater than its geometrical cross-sectional area...."
Regeneration revisited. The Tesla Connection by Gary L. Peterson Citat: "...So it may be said that Tesla anticipated the technique of regenerative feedback to increase detector sensitivity...A detailed description of how the negative resistance, negative inductance circuit works, including a differential form of the active antenna circuit and other pertinent information, can be found in U.S. Patent No. 5,296,866, Mar. 22, 199..."
Gaugebosoner
Kvantemekanik
Kvanteelektrodynamik | danish | 0.752863 |
humans_more_adapted_to_light_mode_or_dark_mode/Trichromacy.txt |
Trichromacy or trichromatism is the possession of three independent channels for conveying color information, derived from the three different types of cone cells in the eye. Organisms with trichromacy are called trichromats.
The normal explanation of trichromacy is that the organism's retina contains three types of color receptors (called cone cells in vertebrates) with different absorption spectra. In actuality, the number of such receptor types may be greater than three, since different types may be active at different light intensities. In vertebrates with three types of cone cells, at low light intensities the rod cells may contribute to color vision.
Humans and other animals that are trichromats[edit]
Humans and some other mammals have evolved trichromacy based partly on pigments inherited from early vertebrates. In fish and birds, for example, four pigments are used for vision. These extra cone receptor visual pigments detect energy of other wavelengths, sometimes including ultraviolet. Eventually two of these pigments were lost (in placental mammals) and another was gained, resulting in trichromacy among some primates. Humans and closely related primates are usually trichromats, as are some of the females of most species of New World monkeys, and both male and female howler monkeys.
Recent research suggests that trichromacy may also be quite general among marsupials. A study conducted regarding trichromacy in Australian marsupials suggests the medium wavelength sensitivity (MWS), cones of the honey possum (Tarsipes rostratus) and the fat-tailed dunnart (Sminthopsis crassicaudata) are features coming from the inherited reptilian retinal arrangement. The possibility of trichromacy in marsupials potentially has another evolutionary basis than that of primates. Further biological and behavioural tests may verify if trichromacy is a common characteristic of marsupials.
Most other mammals are currently thought to be dichromats, with only two types of cone (though limited trichromacy is possible at low light levels where the rods and cones are both active). Most studies of carnivores, as of other mammals, reveal dichromacy; examples include the domestic dog, the ferret, and the spotted hyena. Some species of insects (such as honeybees) are also trichromats, being sensitive to ultraviolet, blue and green instead of blue, green and red.
Research indicates that trichromacy allows animals to distinguish brightly colored fruit and young leaves from other vegetation that is not beneficial to their survival. Another theory is that detecting skin flushing and thereby mood may have influenced the development of primate trichromate vision. The color red also has other effects on primate and human behavior as discussed in the color psychology article.
Types of cones specifically found in primates[edit]
Primates are the only known placental mammalian trichromats.
Their eyes include three different kinds of cones, each containing a different photopigment (opsin). Their peak sensitivities lie in the blue (short-wavelength S cones), green (medium-wavelength M cones) and yellow-green (long-wavelength L cones) regions of the color spectrum. S cones make up 5–10% of the cones and form a regular mosaic. Special bipolar and ganglion cells pass those signals from S cones and there is evidence that they have a separate signal pathway through the thalamus to the visual cortex as well. On the other hand, the L and M cones are hard to distinguish by their shapes or other anatomical means – their opsins differ in only 15 out of 363 amino acids, so no one has yet succeeded in producing specific antibodies to them. But Mollon and Bowmaker did find that L cones and M cones are randomly distributed and are in equal numbers.
Mechanism of trichromatic color vision[edit]
Normalised responsivity spectra of human cone cells
Illustration of color metamerism:In column 1, a ball is illuminated by monochromatic light. Multiplying the spectrum by the cones' spectral sensitivity curves gives the response for each cone type.In column 2, metamerism is used to simulate the scene with blue, green and red LEDs, giving a similar response.
Trichromatic color vision is the ability of humans and some other animals to see different colors, mediated by interactions among three types of color-sensing cone cells. The trichromatic color theory began in the 18th century, when Thomas Young proposed that color vision was a result of three different photoreceptor cells. From the middle of the 19th century, in his Treatise on Physiological Optics, Hermann von Helmholtz later expanded on Young's ideas using color-matching experiments which showed that people with normal vision needed three wavelengths to create the normal range of colors. Physiological evidence for trichromatic theory was later given by Gunnar Svaetichin (1956).
Each of the three types of cones in the retina of the eye contains a different type of photosensitive pigment, which is composed of a transmembrane protein called opsin and a light-sensitive molecule called 11-cis retinal. Each different pigment is especially sensitive to a certain wavelength of light (that is, the pigment is most likely to produce a cellular response when it is hit by a photon with the specific wavelength to which that pigment is most sensitive). The three types of cones are L, M, and S, which have pigments that respond best to light of long (especially 560 nm), medium (530 nm), and short (420 nm) wavelengths respectively.
Since the likelihood of response of a given cone varies not only with the wavelength of the light that hits it but also with its intensity, the brain would not be able to discriminate different colors if it had input from only one type of cone. Thus, interaction between at least two types of cone is necessary to produce the ability to perceive color. With at least two types of cones, the brain can compare the signals from each type and determine both the intensity and color of the light. For example, moderate stimulation of a medium-wavelength cone cell could mean that it is being stimulated by very bright red (long-wavelength) light, or by not very intense yellowish-green light. But very bright red light would produce a stronger response from L cones than from M cones, while not very intense yellowish light would produce a stronger response from M cones than from other cones. Thus trichromatic color vision is accomplished by using combinations of cell responses.
It is estimated that the average human can distinguish up to ten million different colors.
See also[edit]
Visual system
Monochromacy
Dichromacy
Tetrachromacy
Pentachromacy
Mantis shrimp (dodecachromats)
Evolution of color vision in primates
Young–Helmholtz theory
LMS color space | biology | 32632 | https://sv.wikipedia.org/wiki/Tryptofan | Tryptofan | Tryptofan (förkortas Trp eller W) är inom biokemi en av de 20 aminosyror som är byggstenar i proteiner. Den tillhör gruppen opolära, hydrofoba aminosyror och är en av de essentiella aminosyrorna, som kroppen inte själv kan tillverka, och som därför måste tillföras i födan. Bara L-stereoisomeren av tryptofan används som strukturellt enzymprotein; D-stereoisomeren är vanligast förekommande i naturligt producerade peptider. Det utmärkande strukturella kännetecknet för tryptofan är att den har en indol-grupp. Den är en av de två aminosyror som motsvaras av endast ett kodon (UGG) i den genetiska koden.
Tryptofan är också ett utgångsämne (substrat) vid kroppens tillverkning av serotonin och melatonin som har betydelse för sömn, avslappning och stämningsläge och även blodkärlssammandragande. Tryptofan kan även användas för bildning av niacin. I mat finns tryptofan i proteinrik föda, främst i kött och hårdost men även i mjölk och spannmål (se havregryn). Vissa nötter och frön har en hög halt av tryptofan; särskilt kan nämnas pumpafrökärnor och chiafrön. Kynurenin bildas i omsättningen av tryptofan.
Hos växter, svampar och bakterier är tryptofan substrat för biosyntesen av indolättiksyra.
Innehåll i olika livsmedel
Källa USA:s jordbruksdepartements livsmedelsdatabas
Fluorescensmätningar med hjälp av tryptofan
Tryptofan är luminiscent och kan därför vara till hjälp vid koncentrationsbestämningar av proteinlösningar. De flesta fluorescensemissionerna av ett veckat protein sker på grund av excitationen av tryptofan. En del emissioner sker på grund av de aromatiska aminosyrorna tyrosin och fenylalanin. Man får dock se upp för disulfidbryggor (cystein kan bilda dessa) som också har ansenlig absorbans vid dessa våglängder. Tryptofan exciteras av fotoner med våglängderna 280–300 nm (nära UV) och erhåller en emissionstopp som är solvatokromatisk (möjligheten för en kemisk substans att ändra färg efter förändring i av lösningsmedlet, i detta fall polaritet hos lösningen) mellan 300 och 350 nm, beroende på lösningens polaritet. Ifall tryptofanerna är exponerade mot något polärt (till exempel ett lösningsmedel såsom vatten, etanol etcetera) kommer toppen på fluorescensen från tryptofan att närma sig våglängden 350 nm. Då tryptofan är i hydrofob (opolär) miljö (till exempel proteinets inre delar, ett denatureringsmedel etcetera) kommer toppen på fluorescensen att närma sig 300 nm (blåskift).
Det är därför man kan använda tryptofanfluorescens vid diagnos av konformationen (tertiärstruktur) hos ett protein. Problemet är att tryptofans fluorescens är starkt påverkad av närliggande protoniserade grupper, som till exempel asparagin och glycin, som kan orsaka utsläckning av tryptofans exciterade tillstånd. Även energiöverföring mellan tryptofan och andra fluorescerande aminosyror är möjlig, vilket påverkar analysen, särskilt när syra använts. Tryptofan är ganska ovanlig i proteiner; oftast innehåller ett protein en eller kanske några stycken tryptofaner. Därför kan tryptofanfluorescens vara en väldigt känslig mätmetod vid konformationsbestämning av individuella tryptofaner. Det som är positivt är att man inte behöver ändra proteinets veckning vid mätningarna; man påverkar inte proteinets egenskaper.
Referenser
Noter
Externa länkar
Aromatiska aminosyror
Tryptaminalkaloider
Kosttillskott | swedish | 0.813991 |
humans_more_adapted_to_light_mode_or_dark_mode/Diurnality.txt |
Diurnality is a form of plant and animal behavior characterized by activity during daytime, with a period of sleeping or other inactivity at night. The common adjective used for daytime activity is "diurnal". The timing of activity by an animal depends on a variety of environmental factors such as the temperature, the ability to gather food by sight, the risk of predation, and the time of year. Diurnality is a cycle of activity within a 24-hour period; cyclic activities called circadian rhythms are endogenous cycles not dependent on external cues or environmental factors except for a zeitgeber. Animals active during twilight are crepuscular, those active during the night are nocturnal and animals active at sporadic times during both night and day are cathemeral.
Plants that open their flowers during the daytime are described as diurnal, while those that bloom during nighttime are nocturnal. The timing of flower opening is often related to the time at which preferred pollinators are foraging. For example, sunflowers open during the day to attract bees, whereas the night-blooming cereus opens at night to attract large sphinx moths.
In animals[edit]
A bearded dragon, a diurnal reptile
Many types of animals are classified as being diurnal, meaning they are active during the day time and inactive or have periods of rest during the night time. Commonly classified diurnal animals include mammals, birds, and reptiles. Most primates are diurnal, including humans. Scientifically classifying diurnality within animals can be a challenge, apart from the obvious increased activity levels during the day time light.
Evolution of diurnality[edit]
A chimpanzee, a diurnal simian
Initially, most animals were diurnal, but adaptations that allowed some animals to become nocturnal is what helped contribute to the success of many, especially mammals. This evolutionary movement to nocturnality allowed them to better avoid predators and gain resources with less competition from other animals. This did come with some adaptations that mammals live with today. Vision has been one of the most greatly affected senses from switching back and forth from diurnality to nocturnality, and this can be seen using biological and physiological analysis of rod nuclei from primate eyes. This includes losing two of four cone opsins that assists in colour vision, making many mammals dichromats. When early primates converted back to diurnality, better vision that included trichromatic colour vision became very advantageous, making diurnality and colour vision adaptive traits of simiiformes, which includes humans. Studies using chromatin distribution analysis of rod nuclei from different simian eyes found that transitions between diurnality and nocturnality occurred several times within primate lineages, with switching to diurnality being the most common transitions.
Still today, diurnality seems to be reappearing in many lineages of other animals, including small rodent mammals like the Nile grass rat and golden mantle squirrel and reptiles. More specifically, geckos, which were thought to be naturally nocturnal have shown many transitions to diurnality, with about 430 species of geckos now showing diurnal activity. With so many diurnal species recorded, comparative analysis studies using newer lineages of gecko species have been done to study the evolution of diurnality. With about 20 transitions counted for the gecko lineages, it shows the significance of diurnality. Strong environmental influences like climate change, predation risk, and competition for resources are all contributing factors. Using the example of geckos, it is thought that species like Mediodactylus amictopholis that live at higher altitudes have switched to diurnality to help gain more heat through the day, and therefore conserve more energy, especially when colder seasonal temperatures hit.
Light[edit]
Light is one of the most defining environmental factors that determines an animal's activity pattern. Photoperiod or a light dark cycle is determined by the geographical location, with day time being associated with much ambient light, and night time being associated with little ambient light. Light is one of the strongest influences of the suprachiasmatic nucleus (SCN) which is part of the hypothalamus in the brain that controls the circadian rhythm in most animals. This is what determines whether an animal is diurnal or not. The SCN uses visual information like light to start a cascade of hormones that are released and work on many physiological and behavioural functions.
Light can produce powerful masking effects on an animal's circadian rhythm, meaning that it can "mask" or influence the internal clock, changing the activity patterns of an animal, either temporarily or over the long term if exposed to enough light over a long period of time. Masking can be referred to either as positive masking or negative masking, with it either increasing an diurnal animals activity or decreasing a nocturnal animal's activity, respectively. This can be depicted when exposing different types of rodents to the same photoperiods. When a diurnal Nile grass rat and nocturnal mouse are exposed to the same photoperiod and light intensity, increased activity occurred within the grass rat (positive masking), and decreased activity within the mouse (negative masking).
Even small amounts of environmental light change have shown to have an effect on the activity of mammals. An observational study done on the activity of nocturnal owl monkeys in the Gran Chaco in South America showed that increased amounts of moonlight at night increased their activity levels through the night which led to a decrease of daytime activity. Meaning that for this species, ambient moonlight is negatively correlated with diurnal activity. This is also connected with the foraging behaviours of the monkeys, as when there were nights of little to no moonlight, it affected the monkey's ability to forage efficiently, so they were forced to be more active in the day to find food.
Other environmental influences[edit]
Diurnality has shown to be an evolutionary trait in many animal species, with diurnality mostly reappearing in many lineages. Other environmental factors like ambient temperature, food availability, and predation risk can all influence whether an animal will evolve to be diurnal, or if their effects are strong enough, then mask over their circadian rhythm, changing their activity patterns to becoming diurnal. All three factors often involve one another, and animals need to be able to find a balance between them if they are to survive and thrive.
Ambient temperature has been shown to affect and even convert nocturnal animals to diurnality as it is a way for them to conserve metabolic energy. Nocturnal animals are often energetically challenged due to being most active in the nighttime when ambient temperatures are lower than through the day, and so they lose a lot of energy in the form of body heat. According to the circadian thermos-energetics (CTE) hypothesis, animals that are expending more energy than they are taking in (through food and sleep) will be more active in the light cycle, meaning they will be more active in the day. This has been shown in studies done on small nocturnal mice in a laboratory setting. When they were placed under a combination of enough cold and hunger stress, they converted to diurnality through temporal niche switching, which was expected. Another similar study that involved energetically challenging small mammals showed that diurnality is most beneficial when the animal has a sheltered location to rest in, reducing heat loss. Both studies concluded that nocturnal mammals do change their activity patterns to be more diurnal when energetically stressed (due to heat loss and limited food availability), but only when predation is also limited, meaning the risks of predation are less than the risk of freezing or starving to death.
In plants[edit]
Many plants are diurnal or nocturnal, depending on the time period when the most effective pollinators, i.e., insects, visit the plant. Most angiosperm plants are visited by various insects, so the flower adapts its phenology to the most effective pollinators. Thus, the effectiveness of relative diurnal or nocturnal species of insects affects the diurnal or nocturnal nature of the plants they pollinate, causing in some instances an adjustment of the opening and closing cycles of the plants. For example, the baobab is pollinated by fruit bats and starts blooming in late afternoon; the flowers are dead within twenty-four hours.
In technology operations[edit]
Services that alternate between high and low utilization in a daily cycle are described as being diurnal. Many websites have the most users during the day and little utilization at night, or vice versa. Operations planners can use this cycle to plan, for example, maintenance that needs to be done when there are fewer users on the web site.
Notes[edit]
^ All human societies are organised in a generally diurnal pattern, and humans have a natural tendency to sleep in the night.
See also[edit]
Look up diurnal in Wiktionary, the free dictionary.
Diurnal cycle
Cathemeral
Chronotype
Crepuscular
Crypsis
Nocturnality | biology | 2739321 | https://sv.wikipedia.org/wiki/Oncopsis%20variabilis | Oncopsis variabilis | Oncopsis variabilis är en insektsart som beskrevs av Fitch 1851. Oncopsis variabilis ingår i släktet Oncopsis och familjen dvärgstritar. Inga underarter finns listade i Catalogue of Life.
Källor
Dvärgstritar
variabilis | swedish | 1.366263 |
humans_more_adapted_to_light_mode_or_dark_mode/Darkness.txt | Darkness is defined as a lack of illumination, an absence of visible light, or a surface that absorbs light, such as a black one.
Human vision is unable to distinguish colors in conditions of very low luminance because the hue-sensitive photoreceptor cells on the retina are inactive when light levels are insufficient, in the range of visual perception referred to as scotopic vision.
The emotional response to darkness has generated metaphorical usages of the term in many cultures, often used to describe an unhappy or foreboding feeling.
"Darkness" may also refer to night, which occurs when the Sun is more than 18° below the horizon.
Scientific[edit]
Perception[edit]
The perception of darkness differs from the mere absence of light due to the effects of after images on perception. In perceiving, the eye is active, and the part of the retina that is unstimulated produces a complementary afterimage.
Physics[edit]
See also: Light and Heat death of the universe
In terms of physics, an object is said to be dark when it absorbs photons, causing it to appear dim compared to other objects. For example, matte black paint does not reflect much visible light and appears dark, whereas white paint reflects much light and appears bright. For more information, see color. An object may appear dark, but it may be bright at a frequency that humans cannot perceive.
A dark area has limited light sources, making things hard to see. Exposure to alternating light and darkness (night and day) has caused several evolutionary adaptations to darkness. When a vertebrate, like a human, enters a dark area, its pupils dilate, allowing more light to enter the eye and improving night vision. Also, the light detecting cells in the human eye (rods and cones) will regenerate more unbleached rhodopsin when adapting to darkness.
One scientific measure of darkness is the Bortle scale, which indicates the night sky's and stars' brightness at a particular location, and the observability of celestial objects at that location.
The material known as Vantablack is one of the darkest substances known, absorbing up to 99.965% of visible light (at 663 nm if the light is perpendicular to the material), and was developed by Surrey NanoSystems in the United Kingdom. The name is a compound of the acronym VANTA (vertically aligned nanotube arrays) and the color black.
Technical[edit]
The color of a point, on a standard 24-bit computer display, is defined by three RGB (red, green, blue) values, each ranging from 0–255. When the red, green, and blue components of a pixel are fully illuminated (255,255,255), the pixel appears white; when all three components are unilluminated (0,0,0), the pixel appears black.
Cultural[edit]
Artistic[edit]
Caravaggio's The Calling of St Matthew uses darkness for its chiaroscuro effects.
Main article: Tints and shades
This section has multiple issues. Please help improve it or discuss these issues on the talk page. (Learn how and when to remove these template messages)
This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (January 2010) (Learn how and when to remove this template message)
This section possibly contains original research. Please improve it by verifying the claims made and adding inline citations. Statements consisting only of original research should be removed. (November 2014) (Learn how and when to remove this template message)
(Learn how and when to remove this template message)
Artists use darkness to emphasize and contrast the presence of light. Darkness can be used as a counterpoint to areas of lightness to create leading lines and voids. Such shapes draw the eye around areas of the painting. Shadows add depth and perspective to a painting. See chiaroscuro for a discussion of the uses of such contrasts in visual media.
Color paints are mixed together to create darkness, because each color absorbs certain frequencies of light. Theoretically, mixing together the three primary colors, or the three secondary colors, will absorb all visible light and create black. In practice, it is difficult to prevent the mixture from taking on a brown tint.
Literature[edit]
Separation of light and darkness on the first day of creation, from the Sistine Chapel ceiling by Michelangelo
Further information: Light and darkness
As a poetic term in the Western world, darkness is used to connote the presence of shadows, evil, and foreboding, or in modern parlance, to connote that a story is grim, heavy, and/or depressing.
Religion[edit]
The first creation narrative in Judaism and Christianity begins with darkness, into which is introduced the creation of light, and the separation of this light from the darkness (as distinct from the creation of the Sun and Moon on the fourth day of creation). Thus, although both light and darkness are included in the comprehensive works of God, darkness was considered "the second to last plague" (Exodus 10:21), and the location of "weeping and gnashing of teeth" (Matthew 8:12).
Erebus was a primordial deity in Greek mythology, representing the personification of darkness.
Philosophy[edit]
In Chinese philosophy, yin is the complementary feminine part of the taijitu and is represented by a dark lobe.
Poetry[edit]
The use of darkness as a rhetorical device has a long-standing tradition. William Shakespeare, working in the 16th and 17th centuries, made a character called the "prince of darkness" (King Lear: III, iv) and gave darkness jaws with which to devour love. (A Midsummer Night's Dream: I, i) Geoffrey Chaucer, a 14th-century Middle English writer of The Canterbury Tales, wrote that knights must cast away the "workes of darkness". In Divine Comedy, Dante described hell as "solid darkness stain'd".
Language[edit]
In Old English there were three words that could mean darkness: heolstor, genip, and sceadu. Heolstor also meant "hiding-place" and became holster. Genip meant "mist" and fell out of use like many strong verbs. It is however still used in the Dutch saying "in het geniep" which means secretly. Sceadu meant "shadow" and remained in use. The word dark eventually evolved from the word deorc.
See also[edit]
Lightness
Shadow
Theory of colours
Nyctophobia | biology | 282808 | https://da.wikipedia.org/wiki/Skygge | Skygge | En skygge er et område som er mindre belyst end omgivelserne på grund af at et lysbrydende objekt er placeret i mellem området og en lyskilde. Man siger at objektet kaster skygge. Lyskilden kan f.eks. være solen, et stearinlys eller en lampe. Skygger tager form efter det lysbrydende objekt, dog kan skyggen være deformeret eller forvredet afhængig af strukturen af underlaget den falder på, og afhængig af vinklen hvormed lyset rammer objektet. Jo mindre vinklen er mellem lysets retning og den overflade som skyggen falder på, desto længere er skyggen. Dette ses f.eks. sidst på eftermiddagen og om aftenen, når solen er ved at gå ned bag horisonten. Hvis lyskilden befinder sig meget tæt på objektet bliver skyggen meget stor.
Kanten på en skygge vil være mere veldefineret i skarpt lys end i svagt. Dette skyldes at lyset spredes. Hvis lyset falder tæt ind på kanten af et objekt som befinder sig tæt ved den overflade den kaster skygge på, vil skyggens kant være meget skarp.
Ved en måneformørkelse er jorden det lysbrydende objekt og kaster skygge på månen.
Brug af skygge i kunsten
Billedkunstnere har altid været inspireret af lys/skygge-virkninger. Dette ses tydelig ved relieffer og tredimensionale fremstillinger som statuer og skulpturer, hvis placering i forhold til lyskilderne bidrager til den endelige virkning.
I malerkunsten bruger kunstnerne ofte gråtoner til at skabe en tredimenional effekt ved at efterligne skyggevirkningerne. For malerkunsten som efterligner naturen, er det vigtig at lægge mærke til farvetonerne på skyggepartierne (der er ofte et blåtonerr fra himmellyset, men også farvereflekser fra omgivelserne som er belyst).
Andre typer af skygger
I overført betydning anvendes ordet som en form for stråling, f.eks. radioskygge, der er radiosignaler der f.eks. bliver standset af et bjerg og derfor ikke kan modtages.
Udtrykket regnskygge beskriver situationen i et område, som ligger i ly af en bjergkæde og derfor får mindre nedbør, end det er normalt for regionen.
Se også
Optik | danish | 0.663174 |
humans_more_adapted_to_light_mode_or_dark_mode/Human.txt |
Humans (Homo sapiens) or modern humans are the most common and widespread species of primate, and the last surviving species of the genus Homo. They are great apes characterized by their hairlessness, bipedalism, and high intelligence. Humans have large brains, enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools, and form complex social structures and civilizations. Humans are highly social, with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states. As such, social interactions between humans have established a wide variety of values, social norms, languages, and traditions (collectively termed institutions), each of which bolsters human society. Humans are also highly curious: the desire to understand and influence phenomena has motivated humanity's development of science, technology, philosophy, mythology, religion, and other frameworks of knowledge; humans also study themselves through such domains as anthropology, social science, history, psychology, and medicine. As of March 2024, there are estimated to be more than 8 billion humans alive.
Although some scientists equate the term "humans" with all members of the genus Homo, in common usage it generally refers to Homo sapiens, the only extant member. Extinct members of the genus Homo are known as archaic humans, and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa, they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence, interbreeding with Homo sapiens, or inability to adapt to climate change.
For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution, which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change. Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle.
Genes and the environment influence human biological variation in visible characteristics, physiology, disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic: generally, males have greater body strength and females have a higher body fat percentage. At puberty, humans develop secondary sex characteristics. Females are capable of pregnancy, usually between puberty, at around 12 years old, and menopause, around the age of 50.
Humans are omnivorous, capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus. Humans can survive for up to eight weeks without food and several days without water. Humans are generally diurnal, sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death. Often, both the mother and the father provide care for their children, who are helpless at birth.
Humans have a large, highly developed, and complex prefrontal cortex, the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory; they have flexible facial expressions, self-awareness, and a theory of mind. The human mind is capable of introspection, private thought, imagination, volition, and forming views on existence. This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language.
Humans' advanced technology has enabled them to spread to all the continents of the globe as well as to outer space, and to command profound influence on the biosphere and environment. The latter has prompted some geologists to demarcate the time from the emergence of human civilization till present as a separate geological epoch: the Anthropocene (with anthropo- deriving from the Ancient Greek word for "human", ἄνθρωπος).
Etymology and definition
Further information: Names for the human species and Human taxonomy
Carl Linnaeus coined the name Homo sapiens and is the type specimen of the species
All modern humans are classified into the species Homo sapiens, coined by Carl Linnaeus in his 1735 work Systema Naturae. The generic name "Homo" is a learned 18th-century derivation from Latin homō, which refers to humans of either sex. The word human can refer to all members of the Homo genus, although in common usage it generally just refers to Homo sapiens, the only extant species. The name "Homo sapiens" means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals, should be included as a separate species of humans or as a subspecies of H. sapiens.
Human is a loanword of Middle English from Old French humain, ultimately from Latin hūmānus, the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity) as well as to human males. It may also refer to individuals of either sex.
Despite the fact that the word animal is colloquially used as an antonym for human, and contrary to a common biological misconception, humans are animals. The word person is often used interchangeably with human, but philosophical debate exists as to whether personhood applies to all humans or all sentient beings, and further if one can lose personhood (such as by going into a persistent vegetative state).
Evolution
Main article: Human evolution
Humans are apes (superfamily Hominoidea). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo), then gorillas (genus Gorilla), and finally, chimpanzees and bonobos (genus Pan). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct.
Reconstruction of Lucy, the first Australopithecus afarensis skeleton found
The genus Homo evolved from Australopithecus. Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus. The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia, and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan. Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis, the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier.
The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second (Southern Dispersal) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii, Easter Island, Madagascar, and New Zealand in the years 300 to 1280 CE.
Human evolution was not a simple linear or branched progression but involved interbreeding between related species. Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans, may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans.
Human evolution is characterized by a number of morphological, developmental, physiological, and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees. The most significant of these adaptations are hairlessness, obligate bipedalism, increased brain size and decreased sexual dimorphism (neoteny). The relationship between all these changes is the subject of ongoing debate.
Hominoidea (hominoids, apes)
Hylobatidae (gibbons)
Hominidae (hominids, great apes)
Ponginae
Pongo (orangutans)
Pongo abelii
Pongo tapanuliensis
Pongo pygmaeus
Homininae (hominines)
Gorillini
Gorilla (gorillas)
Gorilla gorilla
Gorilla beringei
Hominini (hominins)
Panina
Pan (chimpanzees)
Pan troglodytes
Pan paniscus
Hominina (homininans)
Homo sapiens (humans)
History
Main article: Human history
Prehistory
Main article: Prehistory
Overview map of the peopling of the world by early human migration during the Upper Paleolithic, following to the Southern Dispersal paradigm
Until about 12,000 years ago, all humans lived as hunter-gatherers. The Neolithic Revolution (the invention of agriculture) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea, and the Sahel and West Savanna regions of Africa.
Access to food surplus led to the formation of permanent human settlements, the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations.
Ancient
Main article: Ancient history
Great Pyramids of Giza, Egypt
An urban revolution took place in the 4th millennium BCE with the development of city-states, particularly Sumerian cities located in Mesopotamia. It was in these cities that the earliest known form of writing, cuneiform script, appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation. They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture, Minoans and the Shang dynasty, rose to prominence in new areas.
The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages. During this period iron started replacing bronze, leading to the Iron Age.
In the 5th century BCE, history started being recorded as a discipline, which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars. In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions.
Medieval
Main article: Post-classical history
Medieval French manuscript illustration of the three classes of medieval society from the 13th-century Li Livres dou Santé
Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages. During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age, inspiring achievements in architecture, the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England, the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims.
In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast. Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific.
Modern
Main articles: Early modern period and Late modern period
James Watt's steam engine
The early modern period in Europe and the Near East (c. 1450–1800) began with the final defeat of the Byzantine Empire, and the rise of the Ottoman Empire. Meanwhile, Japan entered the Edo period, the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance, starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas. This expansion led to the Atlantic slave trade and the genocide of Native American peoples. This period also marked the Scientific Revolution, with great advances in mathematics, mechanics, astronomy and physiology.
The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology, major innovations in transport and energy development. The United States of America underwent great change, going from a small group of colonies to one of the global superpowers. The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World, while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania.
A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War, one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War, involving almost all of the world's countries. The war's destruction led to the collapse of most global empires, leading to widespread decolonization.
Contemporary
Main article: Contemporary history
Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race, ending in the collapse of the Soviet Union. The current Information Age, spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected.
Habitat and population
Further information: Human geography and Demography
Population statisticsMosaic cartogram showing the distribution of the global population based on 2018 UN data. Each of the 15,266 pixels represents the home country of 500,000 people – cartogram by Max Roser for Our World in DataChoropleth showing Population density (people per square kilometer) estimates by 30 arc-second grid in 2020World population8.1 billionPopulation density16/km (41/sq mi) by total area54/km (140/sq mi) by land areaLargest citiesTokyo, Delhi, Shanghai, São Paulo, Mexico City, Cairo, Mumbai, Beijing, Dhaka, Osaka, New York-Newark, Karachi, Buenos Aires, Chongqing, Istanbul, Kolkata, Manila, Lagos, Rio de Janeiro, Tianjin, Kinshasa, Guangzhou, Los Angeles-Long Beach-Santa Ana, Moscow, Shenzhen, Lahore, Bangalore, Paris, Jakarta, Chennai, Lima, Bogota, Bangkok, London
Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence, such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation, urban planning, construction, deforestation and desertification. Human settlements continue to be vulnerable to natural disasters, especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics, increasing knowledge or enhancing the exchange of resources.
Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms, although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa, India, Russia, Australia, Fiji, United States and Brazil (each located in a different biogeographical realm).
By using advanced tools and clothing, humans have been able to extend their tolerance to a wide variety of temperatures, humidities, and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest, arid desert, extremely cold arctic regions, and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%).
Within the last century, humans have explored challenging environments such as Antarctica, the deep sea, and outer space. Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific, military, or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft. Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station.
Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%.
Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues, first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals.
In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums. Humans have had a dramatic effect on the environment. They are apex predators, being rarely preyed upon by other species. Human population growth, industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life.
Biology
Anatomy and physiology
Main article: Human body
Diagram of the human skeleton
Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.32.1.2.3. Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth. Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars, with some individuals having them congenitally absent.
Humans share with chimpanzees a vestigial tail, appendix, flexible shoulder joints, grasping fingers and opposable thumbs. Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling, hearing and digesting proteins. While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair, most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet.
It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged. Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals.
Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger.
Genetics
Main article: Human genetics
A graphical representation of the standard human karyotype, including both the female (XX) and male (XY) sex chromosomes (bottom right), as well as the mitochondrial genome (shown to scale as "MT" at bottom left). Further information: Karyotype
Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes, each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes. Like other mammals, humans have an XY sex-determination system, so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood.
While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years.
The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms. African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas. By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA, which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve, must have lived around 90,000 to 200,000 years ago.
Life cycle
See also: Childbirth and Life expectancy
A 10 mm human embryo at 5 weeks
Most human reproduction takes place by internal fertilization via sexual intercourse, but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus. Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions.
Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries.
Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth, humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy, childhood, adolescence, adulthood and old age. The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis), rather than by continuing to bear children into old age.
The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018, the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic, it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world, the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide.
Human life stages
Infant boy and girl
Boy and girl before puberty (children)
Adolescent male and female
Adult man and woman
Elderly man and woman
Diet
Main article: Human nutrition
Humans living in Bali, Indonesia, preparing a meal
Humans are omnivorous, capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous. In some cases, dietary restrictions in humans can lead to deficiency diseases; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science.
Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game, which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus. Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture, a gradual process called the Neolithic Revolution. These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture.
In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation. Childhood malnutrition is also common and contributes to the global burden of disease. However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries. Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an "obesity epidemic." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet.
Biological variation
Main article: Human genetic variation
Changes in the number and order of genes (A–D) create genetic diversity within and between population.
There is biological variation in the human species – with traits such as blood type, genetic diseases, cranial features, facial features, organ systems, eye color, hair color and texture, height and build, and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin, and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet, exercise, and sleep patterns.
There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk. Sickle cell anemia, which may provide increased resistance to malaria, is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions, tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes. Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau.
Human hair ranges in color from red to blond to brown to black, which is the most frequent. Hair color depends on the amount of melanin, with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach, or even nearly white or colorless in cases of albinism. It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D, which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation.
A Libyan, a Nubian, a Syrian, and an Egyptian, drawing by an unknown artist after a mural of the tomb of Seti I
There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other.
Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa, and particularly West Africa, have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans.
Humans are a gonochoric species, meaning they are divided into male and female sexes. The greatest degree of genetic variation exists between males and females. While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation. As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare.
Psychology
Main article: Psychology
Drawing of the human brain, showing several important structures
The human brain, the focal point of the central nervous system in humans, controls the peripheral nervous system. In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion, it is also the locus of "higher" order functioning such as thought, reasoning, and abstraction. These cognitive processes constitute the mind, and, along with their behavioral consequences, are studied in the field of psychology.
Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition. This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to.
There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in "mental time travel". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind.
Sleep and dreaming
Main articles: Sleep and Dream
Humans are generally diurnal. The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort.
During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep. The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming, where the dreamer is self-aware. Dreams can at times make a creative thought occur or give a sense of inspiration.
Consciousness and thought
Main articles: Consciousness and Cognition
Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection, private thought, imagination and volition. It now often includes some kind of experience, cognition, feeling or perception. It may be 'awareness', or 'awareness of awareness', or self-awareness. There might be different levels or orders of consciousness, or different kinds of consciousness, or just one kind with different features.
The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses, and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition, the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development. Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population.
Motivation and emotion
Main articles: Motivation and Emotion
Illustration of grief from Charles Darwin's 1872 book The Expression of the Emotions in Man and Animals
Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization.
Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. They are often intertwined with mood, temperament, personality, disposition, creativity, and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal.
Emotional experiences perceived as pleasant, such as joy, interest or contentment, contrast with those perceived as unpleasant, like anxiety, sadness, anger, and despair. Happiness, or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects, while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life. Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted.
Sexuality and love
Main articles: Human sexuality and Love
Human parents often display familial love for their children.
For humans, sexuality involves biological, erotic, physical, emotional, social, or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions, including the human sexual response cycle. Sexuality also affects and is affected by cultural, political, legal, philosophical, moral, ethical, and religious aspects of life. Sexual desire, or libido, is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often.
Humans can fall anywhere along a continuous scale of sexual orientation, although most humans are heterosexual. While homosexual behavior occurs in some other animals, only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation, as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well.
Love most commonly refers to a feeling of strong attraction or emotional attachment. It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine, norepinephrine, serotonin and other chemicals stimulate the brain's pleasure center, leading to side effects such as increased heart rate, loss of appetite and sleep, and an intense feeling of excitement.
Culture
Main articles: Culture and Cultural universal
Human society statisticsMost widely spoken languagesEnglish, Mandarin Chinese, Hindi, Spanish, Standard Arabic, Bengali, French, Russian, Portuguese, UrduMost practiced religionsChristianity, Islam, Hinduism, Buddhism, folk religions, Sikhism, Judaism, unaffiliated
Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the "folk physics" required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning.
Language
Main article: Language
Principal language families of the world (and in some cases geographic groups of families). For greater detail, see Distribution of languages in the world.
While many species communicate, language is unique to humans, a defining feature of humanity, and a cultural universal. Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement, using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors.
Language differs from other forms of communication in that it is modality independent; the same meanings can be conveyed through different media, audibly in speech, visually by sign language or writing, and through tactile media such as braille. Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct.
The arts
Main article: The arts
Human arts can take many forms including visual, literary, and performing. Visual art can range from paintings and sculptures to film, fashion design, and architecture. Literary arts can include prose, poetry, and dramas. The performing arts generally involve theatre, music, and dance. Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation, video games, and medicine. As well as providing entertainment and transferring knowledge, the arts are also used for political purposes.
The Deluge tablet of the Gilgamesh epic in Akkadian
Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage.
Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures. There exists a wide variety of music genres and ethnic musics; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment. Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain.
Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh, first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation.
Tools and technologies
Main articles: Tool and Technology
The SCMaglev, the fastest train in the world clocking in at 603 km/h (375 mph) as of 2015
Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated, thus proving essential in the development of agriculture – what is known as the Neolithic Revolution.
China developed paper, the printing press, gunpowder, the compass and other important inventions. The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel, which is used in railways, skyscrapers and many other products. This coincided with the Industrial Revolution, where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially, with major innovations in the 20th century including: electricity, penicillin, semiconductors, internal combustion engines, the Internet, nitrogen fixing fertilisers, airplanes, computers, automobiles, contraceptive pills, nuclear fission, the green revolution, radio, scientific plant breeding, rockets, air conditioning, television and the assembly line.
Religion and spirituality
Main articles: Religion and Spirituality
Shango, the Orisha of fire, lightning, and thunder, in the Yoruba religion, depicted on horseback
Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural, sacred or divine, and practices, values, institutions and rituals associated with such belief. Some religions also have a moral code. The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago). It may have evolved to play a role in helping enforce and encourage cooperation between humans.
Religion manifests in diverse forms. Religion can include a belief in life after death, the origin of life, the nature of the universe (religious cosmology) and its ultimate fate (eschatology), and moral or ethical teachings. Views on transcendence and immanence vary substantially; traditions variously espouse monism, deism, pantheism, and theism (including polytheism and monotheism).
Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims, Hindus and Buddhists. As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious, including those with no religious beliefs or no identity with any religion.
Science and philosophy
Main articles: Science and Philosophy
The Dunhuang map, a star map showing the North Polar region. China circa 700.
An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy.
Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period. Other early advances in science came from the Han Dynasty in China and during the Islamic Golden Age. The scientific revolution, near the end of the Renaissance, led to the emergence of modern science.
A chain of events and influences led to the development of the scientific method, a process of observation and experimentation that is used to differentiate science from pseudoscience. An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition. All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics), which are concerned with formal systems, the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics, chemistry, biology) and social sciences (e.g., psychology, economics, sociology).
Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics, epistemology, logic, and axiology (which includes ethics and aesthetics).
Society
Main article: Society
Humans often live in family-based social structures
Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power, reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies.
Gender
Main article: Gender
Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex. The most common categorisation is a gender binary of men and women. Many societies recognise a third gender, or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female.
Gender roles are often associated with a division of norms, practices, dress, behavior, rights, duties, privileges, status, and power, with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct, gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic, while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal.
Kinship
Main article: Kinship
All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants (consanguinity), and relations through marriage (affinity). There is also a third type applied to godparents or adoptive children (fictive). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance. All societies have rules of incest taboo, according to which marriage between certain kinds of kin relations are prohibited, and some also have rules of preferential marriage with certain kin relations.
Ethnicity
Main article: Ethnic group
Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry, language, history, society, culture, nation, religion, or social treatment within their residing area. Ethnicity is separate from the concept of race, which is based on physical characteristics, although both are socially constructed. Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries.
Government and politics
Main articles: Government and Politics
The United Nations headquarters in New York City, which houses one of the world's largest political organizations
As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances.
Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy, 17% in a hybrid regime, and 37% in an authoritarian regime. Many countries belong to international organizations and alliances; the largest of these is the United Nations, with 193 member states.
Trade and economics
Main articles: Trade and Economics
The Silk Road (red) and spice trade routes (blue)
Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian. The first truly international trade routes were around the spice trade through the Roman and medieval periods.
Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities; the oldest being in the form of cattle and the most widely used being cowrie shells. Money has since evolved into governmental issued coins, paper and electronic money. Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population.
Conflict
Further information: War and Violence
American troops landing at Normandy, WWII.
Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered, rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations with rates of homicide in societies that have legal systems and strong cultural attitudes against violence at about 0.01%.
The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict.
See also
Mammals portalEvolutionary biology portalScience portal
List of human evolution fossils
Timeline of human evolution
Notes
^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects.
^ Cities with over 10 million inhabitants as of 2018.
^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma), but recent research suggest it might be more complicated than that. | biology | 494108 | https://no.wikipedia.org/wiki/Menneske | Menneske | ? H. s. denisova
† H. s. idaltu
H. s. sapiens
Menneske (Homo sapiens) er en art med tobeinte primater (Primates) i familien av store aper (Hominidae) og tilhører menneskeslekten (Homo). Det vitenskapelige navnet kommer fra latin og betyr «det tenkende mennesket». Nålevende mennesker tilhører underarten H. s. sapiens, alle tidligere underarter av vår art er dødd ut eller absorbert i den moderne befolkningen. Menneske kan være både primærkonsument, sekundærkonsument, tertiærkonsument og toppkonsument i en næringskjede.
Karakteristisk for mennesker er artens kombinasjon av å gå på to bein (tobeint), tilpasningsevne (som klær og verktøy), finmotorikk (hender og fingre), evne til å tenke abstrakt (å vise følelser og empati [medfølelse]), skjelne årsakssammenheng (kausalitet), tolke språk og symboler og eventuelt selvbevissthet. Ingen av disse egenskapene er egentlig unike for mennesker individuelt, men finnes også i ulike dyrearter – fra insekter til andre primater og hvaler. Sammen har de satt mennesket i stand til å utvikle samfunn, filosofi, religion, vitenskap, teknologi og kunst.
Mennesker har utviklet seg i forhold til andre arter og har over tid kommet til å dominere utviklingen på planeten Jorden. Som et sosialt vesen har dets strukturer for sivilisasjon og samfunn blitt styrt ved hjelp av politikk, dens kultur og oppfatning av omverdenen ved hjelp av fenomener som religion, filosofi og vitenskapelig utvikling. Gjennom språket har arten også kunnet dokumentere funn, oppdagelser, oppfinnelser og sin egen historie.
Studiet av mennesker er vanligvis delt inn i ulike fagområder. Studiet av mennesker kalles antropologi og studiet av menneskelig evolusjon kalles paleoantropologi. Studiet av menneskelig atferd kan gjøres innenfor psykologi og sosiologi, mens studiet basert på nøytrale etologiske perspektiver (atferdsbiologi) kalles humanetologi. Studiet av menneskelig språk kalles lingvistikk. Studiet av menneskers helse og mer kalles menneskelig medisin, og studiet av dens kropp kan beskrives i menneskelig anatomi og fysiologi. Menneskelig reproduksjon er relatert til både genetikk og seksualitet.
Biologi
Det moderne mennesket har mulighet for å bruke språk på et meget høyt nivå, og har en høyt utviklet hjerne som er i stand til utstrakt abstrakt tenkning og bevissthet. Denne mentale kapasiteten, kombinert med en oppreist kroppsholdning som frigjør dets øvre lemmer til andre aktiviteter enn gange, har gjort mennesket i stand til å bruke verktøy i større grad enn noen annen kjent dyreart. DNA-baserte beviser indikerer at moderne mennesker oppstod i Afrika for omtrent år siden. Mennesker befolker nå samtlige kontinenter og har per 2022 en total populasjon på over 7.8 milliarder individer.
Studiet av mennesket skjer både i naturvitenskapene (humanbiologi), samfunnsvitenskapene (antropologi) og medisin (inkl. psykologi).
Beskrivelse
Et voksent menneske har ca. 1,8 m² hud, 32 tenner, ca. 600 muskler, 206 knokler, over 100 ledd, km blodårer samt 13 milliarder nerveceller. Mennesket har 4–6 liter blod som inneholder omtrent 25 billioner røde blodlegemer. Hjernen veier gjennomsnittlig gram. Mennesket har opp til 5 millioner hår, like mange som en sjimpanse eller gorilla. I motsetning til hos dem, er kroppshårene hos menneske tynne og kortvokste, slik at mennesket framstår som nakent i forhold til sine slektninger.
Mennesket er en svært variabel art. Gjennomsnittsvekten på voksne individer varierer mellom 40 kg hos noen tropiske folkeslag til opp mot 70 kg hos enkelte nordlige grupper. Størrelsesforskjellen på kjønnene er omkring 20 %, større enn hos sjimpanse, men mindre enn det vi finner hos gorilla og orangutang.
Med unntak av ryggsøylen og den store hjerneskallen er menneskekroppen lite spesialisert, og likner den vi finner hos de fleste primater. Øynene er foroverrettet. Tannsettet er noe redusert i forhold til primitive pattedyr, og mangler de lange hjørnetennene som er vanlig for øvrige primater. Hele tannarden er relativt liten og tilbaketrukket i forhold til slektningene, slik at den nederste del av underkjeven stikker fram som en hake. Dette er trolig en tilpasning til å spise mat som må tygges «sideveis», slik som frø og røtter. Fordøyelsessystemet er ganske enkelt og mangler tilpasninger for mer næringsfattig kost slik vi finner det hos gressetere. Som andre primater har mennesket relativt lite spesialiserte lemmer med fem fingre/tær på hver ekstremitet og kragebein. Menneskets føtter er tilpasset til å gå på hele fotsålen (sålegjenger), og mangler tilpasning til klatring slik vi finner hos andre primater.
Evolusjon og systematikk
Biologisk sett utgjør helheten av alle mennesker en art.
Denne ga Linné det vitenskapelige navnet Homo sapiens (latin: i betydningen «det kloke mennesket»).
Menneskets plass i naturen
Menneskets plass i naturen har fra oldtiden av vært et stridstema. I mange religioner, eksempelvis åsatru, gresk mytologi, kristendom og islam blir mennesket beskrevet som en skapning som er skapt (eller har oppstått) spesielt og løsrevet fra den øvrige naturen. Likevel er likhetene med andre levende organismer ikke til å overse, og allerede Aristoteles grupperte mennesket i dyreriket.
Linné plasserte i sitt verk Systema Naturae menneskene blant herredyrene (primater), i samme biologiske slekt som sjimpanse og orangutang. Denne plasseringen var omstridt i hans samtid, men på forespørsel fra biskopen i Uppsala, skrev han: Jeg kan ikke se at det er noen generiske forskjeller. Med «generisk» viste han til de egenskapene som skiller en slekt (genus på latin) fra en annen. Ideen om mennesket som en primat har holdt stand også i lys av de siste to hundre års forskning. Med Charles Darwins evolusjonsteori fikk man for første gang en etterprøvbar teori om stamtrær og slektskap, og menneskets fortid er i dag ganske godt beskrevet gjennom fossilfunn.
Klassifikasjon
Rike: Animalia (dyreriket)
Rekke: Chordata (ryggstrengdyr)
Klasse: Mammalia (pattedyr)
Orden: Primates (primater)
Familie: Hominidae (store aper)
Slekt: Homo (menneskeslekten)
Art: H. sapiens (menneske)
Underart: H. s. sapiens (det moderne mennesket)
Menneske hører også med i en rekke grupper som faller mellom de formelle kategoriene, slik som infraordenen høyere aper, underklassen placentale pattedyr, overklassen amniondyr, overrekken deuterostomier, gruppene opisthokonter og eukaryoter.
Spredning av mennesker
Menneskeaper
Blant menneskeapene er sjimpanser menneskets nærmeste slektninger. Inntil for om lag 12 millioner år siden delte menneskene sin evolusjonære historie med sjimpansene og gorilla. Mennesket og sjimpansene har hatt en komplisert artsdannelsesprosess fra 8 til 4 millioner år siden, der populasjoner ser ut til å ha skilt lag for så å blande seg igjen i flere omganger. Etter dette «skilte de lag», dvs. at menneskene fikk en stamform som de ikke deler med andre menneskeaper. Det finnes flere fossiler som er kandidat til stamformen til menneske og sjimpanser, men disse er svært fragmentariske og det er per i dag usikkert nøyaktig hvem som representerer våre forfedre, sjimpansens forfedre og utdødde sidegreiner. Det finnes derimot godt med fossilt materiale fra utdødde arter som står nærmere mennesker enn andre aper, slik som Australopithecus afarensis og Homo erectus.
Noen av disse er utdødde sidegrener, som vil si at de ikke etterlot seg avkom som har overlevd til i dag. Andre er menneskenes direkte stamformer. Disse er ikke i egentlig forstand «dødd ut» (fordi de jo har etterlatt seg avkom), men har gjennomgått så store endringer at de ikke lenger er gjenkjennelige, såkalte krono-arter. For mange av disse fossile artene er imidlertid statusen usikker. Det vil si at man ikke med sikkerhet vet om de representerte en sidegren, eller om de kan ha bidratt med avkom til nåtidens menneskeart. Hva som har utgjort arter og hva som bare har vært variasjoner innfor en gruppe er også usikkert.
Førmennesker (Australopithecus)
Noen av Australopithecus-artene, som levde for 4,2–1,2 millioner år siden, er f.eks. med sikkerhet sidegrener (bl.a. A. boisei og A. robustus), andre kan ha vært menneskenes stamformer (bl.a. A. anamensis og A. afarensis). De mindre robuste A. afarensis og A. africanus er vanligvis regnet som de linjene som leder til slekten menneskeslekten. Slekten Homo oppsto med bruk av de første steinredskapene for rundt 2,5 millioner år siden, men Australopithecus fortsatte å eksistere. De yngste restene vi kjenner av denne slekten er rundt 1,2 millioner år gamle.
Mennesker (Homo)
Gjennom tidene har det vært flere teorier om det moderne menneskets opprinnelse. I dag er de fleste forskere enige om at moderne Homo sapiens ble utviklet på den afrikanske savannen for mellom og år siden. For om lag år siden vandret grupper ut fra Afrika og spredte seg, først i tropiske strøk, og for kanskje så mye som år siden begynte de også å besette kaldere områder. I prosessen delvis fortrengte de, delvis blandet seg med tidligere utvandringsbølger (neandertalere, denisovere, Homo erectus). Mennesket nådde polare områder for rundt år siden og nådde derved de amerikanske kontinentene via Sibir. I dag er mennesket naturlig utbredt på alle kontinenter utenom Antarktis. Etter hvert som mennesket spredte seg, fortrengte det de tidligere menneskeartene, neandertalere i Europa, Mapa-folket i Asia, Homo erectus i Sørøst-Asia og Homo floresiensis på øya Flores.
Den første representanten for nåtidsmennesket er i Europa Cro-Magnon-mennesket, oppkalt etter et funnsted i Frankrike. Der fant man de første restene etter disse menneskene i 1868. Cro-Magnon spredte seg trolig inn i Europa for omkring år siden.
Menneske (H. sapiens)
Man regner i dag med kun én nålevende underart av mennesket, nåtidsmennesket Homo sapiens sapiens. Utdødde underarter inkluderer Homo sapiens idaltu, funnene fra Omo og skjelettene fra Qafzeh-hulen i Israel. Det eksisterer imidlertid ikke en enhetlig taksonomi som alle er enige i. Disse funnene kan være vanskelige å skille fra eldre slekninger av vår art, men alle har en trekantet forhøyning midt på underkjeven som utgjør haken hos moderne mennesker. Eldre Homo-arter mangler dette tydelige trekket.
Tidligere delte antropologer mennesket inn i raser, men det har man sluttet med (se menneskeraser). Menneskelig variasjon eksisterer (se menneskets kropp), men av politiske og etiske årsaker, spesielt på grunn av misbruk av rasebiologien på første halvdel av 1900-tallet, har man altså sluttet med å dele inn mennesket i annet enn etnisitet.
Referanser
Eksterne lenker
Pattedyr i Norge
1000 artikler enhver Wikipedia bør ha | norwegian_bokmål | 0.472136 |
3D_vision/full.txt | Skip to main content
# Top bar navigation
Frontiers in Neuroscience
About us
About us
* Who we are
* Mission
* Values
* History
* Leadership
* Awards
* Impact and progress
* Frontiers' impact
* Progress Report 2022
* All progress reports
* Publishing model
* How we publish
* Open access
* Fee policy
* Peer review
* Research Topics
* Services
* Societies
* National consortia
* Institutional partnerships
* Collaborators
* More from Frontiers
* Frontiers Forum
* Press office
* Career opportunities
* Contact us
All journals All articles Submit your research
Search
Frontiers in Neuroscience
Sections
Sections
* Auditory Cognitive Neuroscience
* Autonomic Neuroscience
* Brain Imaging Methods
* Decision Neuroscience
* Gut-Brain Axis
* Neural Technology
* Neurodegeneration
* Neurodevelopment
* Neuroendocrine Science
* Neuroenergetics and Brain Health
* Neurogenesis
* Neurogenomics
* Neuromorphic Engineering
* Neuropharmacology
* Neuroprosthetics
* Neuroscience Methods and Techniques
* Perception Science
* Sleep and Circadian Rhythms
* Social and Evolutionary Neuroscience
* Translational Neuroscience
* Visual Neuroscience
Articles Research Topics Editorial Board
About journal
About journal
* Scope
* Field chief editors
* Mission & scope
* Facts
* Journal sections
* Open access statement
* Copyright statement
* Quality
* For authors
* Why submit?
* Article types
* Author guidelines
* Editor guidelines
* Publishing fees
* Submission checklist
* Contact editorial office
About us
About us
* Who we are
* Mission
* Values
* History
* Leadership
* Awards
* Impact and progress
* Frontiers' impact
* Progress Report 2022
* All progress reports
* Publishing model
* How we publish
* Open access
* Fee policy
* Peer review
* Research Topics
* Services
* Societies
* National consortia
* Institutional partnerships
* Collaborators
* More from Frontiers
* Frontiers Forum
* Press office
* Career opportunities
* Contact us
All journals All articles Submit your research
Frontiers in Neuroscience
Sections
Sections
* Auditory Cognitive Neuroscience
* Autonomic Neuroscience
* Brain Imaging Methods
* Decision Neuroscience
* Gut-Brain Axis
* Neural Technology
* Neurodegeneration
* Neurodevelopment
* Neuroendocrine Science
* Neuroenergetics and Brain Health
* Neurogenesis
* Neurogenomics
* Neuromorphic Engineering
* Neuropharmacology
* Neuroprosthetics
* Neuroscience Methods and Techniques
* Perception Science
* Sleep and Circadian Rhythms
* Social and Evolutionary Neuroscience
* Translational Neuroscience
* Visual Neuroscience
Articles Research Topics Editorial Board
About journal
About journal
* Scope
* Field chief editors
* Mission & scope
* Facts
* Journal sections
* Open access statement
* Copyright statement
* Quality
* For authors
* Why submit?
* Article types
* Author guidelines
* Editor guidelines
* Publishing fees
* Submission checklist
* Contact editorial office
Frontiers in Neuroscience
Sections
Sections
* Auditory Cognitive Neuroscience
* Autonomic Neuroscience
* Brain Imaging Methods
* Decision Neuroscience
* Gut-Brain Axis
* Neural Technology
* Neurodegeneration
* Neurodevelopment
* Neuroendocrine Science
* Neuroenergetics and Brain Health
* Neurogenesis
* Neurogenomics
* Neuromorphic Engineering
* Neuropharmacology
* Neuroprosthetics
* Neuroscience Methods and Techniques
* Perception Science
* Sleep and Circadian Rhythms
* Social and Evolutionary Neuroscience
* Translational Neuroscience
* Visual Neuroscience
Articles Research Topics Editorial Board
About journal
About journal
* Scope
* Field chief editors
* Mission & scope
* Facts
* Journal sections
* Open access statement
* Copyright statement
* Quality
* For authors
* Why submit?
* Article types
* Author guidelines
* Editor guidelines
* Publishing fees
* Submission checklist
* Contact editorial office
Submit your research Search
Download article
* Download PDF
* ReadCube
* EPUB
* XML (NLM)
##### Share on
* * *
Export citation
* EndNote
* Reference Manager
* Simple Text file
* BibTex
1,3K
Total views
376
Downloads
1
Citations
Citation numbers are available from Dimensions
View article impact
View altmetric score
##### Share on
* * *
Edited by
Maurice Ptito
Montreal University, Canada
Reviewed by
Laurence Dricot
Université Catholique de Louvain, Belgium
Stuart Trenholm
McGill University, Canada
Table of contents
* Abstract
* 1\. Introduction
* 2\. Materials and methods
* 3\. Results
* 4\. Discussion
* 5\. Conclusion
* Data availability statement
* Ethics statement
* Author contributions
* Funding
* Acknowledgments
* Conflict of interest
* Publisher’s note
* References
Export citation
* EndNote
* Reference Manager
* Simple Text file
* BibTex
Check for updates
Download article
Download
* Download PDF
* ReadCube
* EPUB
* XML (NLM)
## ORIGINAL RESEARCH article
Front. Neurosci. , 11 January 2023
Sec. Perception Science
Volume 16 - 2022 | https://doi.org/10.3389/fnins.2022.962817
This article is part of the Research Topic Brain Plasticity Following Sensory
Loss: From Basic Mechanisms to Therapy View all 12 articles
# Testing geometry and 3D perception in children following vision restoring
cataract-removal surgery
Amber Maimon 1,2* Ophir Netzer 3 Benedetta Heimler 4 Amir Amedi 1,2
* 1 The Baruch Ivcher Institute for Brain, Cognition, and Technology, Baruch Ivcher School of Psychology, Reichman University, Herzliya, Israel
* 2 The Ruth & Meir Rosenthal Brain Imaging Center, Reichman University, Herzliya, Israel
* 3 Gonda Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
* 4 Center of Advanced Technologies in Rehabilitation (CATR), Sheba Medical Center, Ramat Gan, Israel
As neuroscience and rehabilitative techniques advance, age-old questions
concerning the visual experience of those who gain sight after blindness, once
thought to be philosophical alone, take center stage and become the target for
scientific inquiries. In this study, we employ a battery of visual perception
tasks to study the unique experience of a small group of children who have
undergone vision-restoring cataract removal surgery as part of the Himalayan
Cataract Project. We tested their abilities to perceive in three dimensions
(3D) using a binocular rivalry task and the Brock string task, perceive visual
illusions, use cross-modal mappings between touch and vision, and spatially
group based on geometric cues. Some of the children in this study gained a
sense of sight for the first time in their lives, having been born with
bilateral congenital cataracts, while others suffered late-onset blindness in
one eye alone. This study simultaneously supports yet raises further questions
concerning Hubel and Wiesel’s critical periods theory and provides additional
insight into Molyneux’s problem, the ability to correlate vision with touch
quickly. We suggest that our findings present a relatively unexplored
intermediate stage of 3D vision development. Importantly, we spotlight some
essential geometrical perception visual abilities that strengthen the idea
that spontaneous geometry intuitions arise independently from visual
experience (and education), thus replicating and extending previous studies.
We incorporate a new model, not previously explored, of testing children with
congenital cataract removal surgeries who perform the task via vision. In
contrast, previous work has explored these abilities in the congenitally blind
via touch. Taken together, our findings provide insight into the development
of what is commonly known as the visual system in the visually deprived and
highlight the need to further empirically explore an amodal, task-based
interpretation of specializations in the development and structure of the
brain. Moreover, we propose a novel objective method, based on a simple
binocular rivalry task and the Brock string task, for determining congenital
(early) vs. late blindness where medical history and records are partial or
lacking (e.g., as is often the case in cataract removal cases).
## 1\. Introduction
“You’ll learn,” the blind man answered. “There is much to learn in the world.”
And indeed, as discovered by the protagonist in Wells, 1921 short story “The
Country of the Blind,” we have much to learn from the blind and the visually
impaired. Particularly with regard to the neuroscience of vision and the
development of the brain and the senses. Today, actual attempts at restoring
vision allow for true exploration concerning these themes. In particular, by
way of cataract removal. Though cataract removal methods and techniques have
been documented for hundreds of years–with one of the first reported cases
taking place as early as 1615 ( Leffler et al., 2021 ), case studies and
reports on the visual abilities and experiences of people who undergo cataract
removal surgeries are still relatively few and far between ( Fine et al.,
2003 ; Ostrovsky et al., 2006 ).
Cataracts are the leading cause of vision impairment in children, particularly
those residing in low-income countries worldwide ( World Health Organization
[WHO], 2021 ). Several humanitarian efforts are currently underway to change
this unfortunate circumstance and rectify the situation. Among these projects
is project Prakash ( Thomas, 2011 ; Sinha, 2013 ; Sinha et al., 2013 ),
a project with humanitarian and scientific goals led by Prof. Pawan Sinha, and
the Himalayan Cataract Project ( Welling et al., 2013 ; Brant et al., 2021
), founded by Drs. Geoffrey Tabin and Sanduk Ruit that aims to eradicate
curable blindness.
David Hubel and Torsten Wiesel, who later won the 1981 Nobel Prize for this
work, found that deprivation of visual input in the first few months of the
lives of animals (such as cats and monkeys) led to irreversibly abnormal
visual processing ( Wiesel and Hubel, 1965 ; Hubel et al., 1977 ; LeVay
et al., 1980 ). They found that when monocularly deprived of vision, the
percentage of cells driven by the sensory-deprived eye is reduced ( Wiesel
and Hubel, 1963 ). When binocularly deprived of vision, they found a decrease
in the number of binocularly influenced cells. They suggested that this
indicates “a deterioration of innate connections subserving binocular
convergence” ( Wiesel and Hubel, 1974 , p. 1060).
Following from these findings, Hubel and Wiesel (1963) concluded that while
there is a basic organization in place at birth, for proper development and
visual processing, visual input is necessary. They thus formulated the
critical periods hypothesis, which postulates that there is a critical period
for developing the sense of vision (and other senses). If sensory information
is deprived during the critical period, the neuronal morphology and
connectivity are altered in such a way that the sense cannot be gained or
recovered at a later stage ( Wiesel and Hubel, 1965 ; Hubel and Wiesel,
1970 ). In humans, while the greatest chance of visual recovery in the case
of detected and treated visual abnormality is under the age of 5 ( Siu and
Murphy, 2018 ), the critical period for binocularity was thought to decrease
by age 6–8 ( Aslin and Banks, 1978 ), with some studies pointing to the end
of the critical period for stereopsis as falling between the age of 4–5 (
Fawcett et al., 2005 ). Despite this, research conducted specifically on
congenital cataract removal by Prof. Pawan Sinha and others indicates that the
human brain “retains the capacity” for the acquisition of vision even after
extended sensory deprivation during critical periods ( Held et al., 2011 ).
A wealth of research indicates that neuroplasticity can bring about enhanced
development in the intact skills and abilities of the sensory deprived (
Amedi et al., 2005 ; Heimler et al., 2014 ; Heimler and Amedi, 2020 ).
Further support for this comes from studies showing compensatory
neuroplasticity, for example, switching of tasks performed by a specific brain
area leading to enhancement in high-level cognitive functions, such as memory
or language ( Amedi et al., 2003 ; Bedny et al., 2011 or memory in a
causal relationship Amedi et al., 2004 ), or neuroplasticity that underlies
the ability to perform substitution of one sense by another. Contemporary
research on blind users trained with sensory substitution devices that
translate vision to audition show activation in category-specific visual areas
when using the devices for various tasks, such as identification of objects (
Striem-Amit et al., 2012a ), letters ( Reich et al., 2011 ), and numbers (
Abboud et al., 2015 ).
A cataract is a lens opacity that causes visual impairment, sometimes to
complete blindness ( Grałek et al., 2007 ). Cases of visual restoration
following cataract removal represent the true core of both the philosophical
and scientific debate on sight, the senses, and neuroplasticity. Would one who
underwent surgery that allowed them to gain a previously inexperienced sense
of vision be able to “know” what they were seeing? If so, how rapidly and to
what level would the ability to use this knowledge, for example, for
perceiving three dimensions (3D) vision and geometry, come about? These
findings are also interesting for the nature vs. nurture debate concerning
visual properties. This debate dates back to the time of John Locke and his
acquaintance William Molineux, who pondered in correspondence whether a blind
person who could recognize objects by touch would be able to recognize those
same objects by vision, were their vision miraculously restored ( Locke, 1847
; Ferretti and Glenney(eds), 2021 ). We aim to weigh in on several core
questions in this case study. Would children blind from birth in one or both
eyes gain true visual properties? If so, to what extent and how similar or
different is their visual experience from those of the normally sighted? Would
they achieve the level of visual knowledge experienced by the normally sighted
children?
In addition, we specifically explore some still-open questions at the
forefront of research conducted with vision restoration patients. Would these
children have 3D vision? Fine et al. (2003) conducted a case study that
showed that long-term visual deprivation leads to deficits in processing
complex forms, specifically 3D. Would the children be able to correspond what
they now see with what they feel through touch? Prior research indicates, for
example, that the cross-modal transfer of information between the tactile
sense and the newly acquired visual one does not develop immediately. However,
it develops within a few days ( Held et al., 2011 ). Later research
indicates that this correspondence occurs quicker than previously thought (
Chen et al., 2016 ). Would these children be susceptible to visual illusions?
It was commonly believed that susceptibility to visual illusions is visual
experience-dependent ( Gillam, 1980 ). Yet, a study showed that children who
underwent cataract removal surgery (as part of project Prakash) are
susceptible to certain illusions immediately after surgery ( Gandhi et al.,
2015 ). Moreover, how would they perform on tasks requiring the spatial
grouping of visual geometric cues? Research conducted with haptic geometric
cues has led to conflicting conclusion. On the one hand, Marlair et al.
(2021) showed lower performance in the blind than the sighted, but on the
other, Heimler et al. (2021) showed similar performance in the blind as in
the sighted.
This paper aims to provide insight into these key questions, to some extent,
through the individual experiences of eight children who underwent cataract-
removal surgery in Quiha hospital in Ethiopia as part of the Himalayan
Cataract Project. We were able to explore the children’s visual state a few
days after surgery (but due to the circumstances–not before) to shed some
light on the relationship between the behavioral and the neurological. A case
study is particularly warranted in these circumstances due to the exceptional
nature of these cases. The extensive battery of tests we employ allows for
ascertaining the fine details of the children’s visual experience. We believe
this paper serves as a springboard for more research in this challenging field
and paves the way for a deeper understanding of the development of vision and
the senses in general.
In addition, we wish to propose a novel and more objective method for
determining congenital (early) vs. late blindness in children undergoing
cataract-removal surgery. In these cases, particularly in, but not limited to,
low and middle-income countries, it is often difficult to determine the
precise medical background of the children, and their clinical state is often
not adequately documented, leaving the medical and rehabilitative staff often
dependent on reports of the parents alone. We suggest utilizing the findings
of this study, particularly concerning the binocular rivalry and the Brock
String task, as a method for distinguishing cases of congenital (early) and
late blindness in children following cataract surgery.
## 2\. Materials and methods
### 2.1. Participants and ethics
Eight children participated in the study, all of whom underwent vision
restoring or rehabilitating ophthalmological surgery in the days before the
study as part of the Himalayan Cataract Project (see Table 1 for more
details). For the purpose of this study, childhood is defined as below the
universally accepted age of 18 ( McGoldrick, 1991 ). The children presented
with various visual impairments but had no other known diseases or medical
conditions. RS (male, 11 years old) and HB (male, 13 years old) had congenital
cataracts in both eyes. IG (male, 14 years old) had a congenital cataract in
one eye. OB (male, 7 years old), GA (male, 7 years old), AC (female, 10 years
old), AB (male, 12 years old), and GH (female, 10 years old) had trauma-
induced cataracts in one eye. While RS and HB had been blind from birth in
both eyes, and IG blind from birth in one eye, the others had much shorter
periods of vision loss, between 2 weeks to a month, before surgery (see Table
1 for demographic and medical information about the children). All the
children underwent the operation 4–6 days before the study. The children’s
legal guardians gave informed consent to their participation in this study. In
addition, the study was conducted within the hospital setting while the
children were under the care of the hospital staff and adhered to the ethical
guidelines of the declaration of Helsinki.
TABLE 1
Table 1. Demographic and medical information about the children.
### 2.2. Binocular rivalry
All subjects performed a binocular rivalry task and a depth perception task.
The subjects wore classic (generic) paper 3D viewing glasses in the binocular
rivalry task. They were presented with stimuli consisting of two superimposed
cartoon figures (cartoon figures were used as stimuli as the subjects were
children) in red and blue (see examples in Figure 1D ). We asked
participants to close one eye at a time to see each figure separately and then
to look at the image on the screen with both eyes and report whether they see
the two figures alternating. In those with normally developed vision, the
simultaneous presentation of two different images in two colors superimposed
through the red/blue filter leads to a well-documented perceptual phenomenon
of image dominance switching ( Wade, 1998 ). The perceptual dominance of the
images changes such that only one image is perceived at a time, with the
images switching between them (coming in and out of active perception) every
few seconds ( Miller et al., 2000 ; Pettigrew, 2001 ; Blake and
Logothetis, 2002 ).
FIGURE 1
Figure 1. (A) A child in the study that had cataract removal surgery 4–6
days prior to undergoing the binocular rivalry task. (B) A child in the
study undergoing the Brock string task and binocular rivalry task. (C)
Geometrical three dimensional (3D) shapes used for the three-dimensional
cross-modal object recognition task. (D) Superimposed images were used to
test binocular rivalry. (E) Spatial grouping task based on geometric cues
from Dehaene et al. (2006) (detection of the outlier in each group of
geometric cues, for example, the triangle among the quadrilaterals).
On the other hand, when one eye or the other is covered, only one image is
perceived at a time without changing. This phenomenon is closely correlated
with the two-dimensional information presented to our eyes from the outside
world, which is combined into a single three-dimensional representation in the
brain ( Levelt, 1965 ). In this study, the children were instructed to look
at the images first with one eye, then with the other, then with both eyes
while fixating their gaze on the fixation cross at the top center of the image
( Figure 1A ).
### 2.3. Depth perception with the Brock string task
In addition to the binocular rivalry task, all children performed a Brock
string task to test their ability to converge the information acquired by
their two eyes to create binocular 3D vision ( Brock, 1955 ). The instrument
employed in the task is a white string with three beads, one green, one
yellow, and one red, placed along the string’s length at different intervals.
The string and beads used for the task were homemade and not commercial
instruments. One end of the string is held precisely at the tip of the
subject’s nose, while the other is placed at a fixed location with the string
pulled tautly. In this task, the experimenter points sequentially at the three
balls, and the participant must gaze at them, reporting what they (see Figure
1B ). Participants prepared for ∼1 min using the string: the experimenter
pointed sequentially to the different balls on the thread, and the
participants needed to direct their gaze to the ball pointed to by the
experimenter. If the beads appear double to the subject, then it indicates an
inadequacy in the convergence of visual input. If one has binocular depth
perception, s/he will start to see two lines rather than only one line.
### 2.4. Spatial grouping based on geometric cues
Four children, RS, HB (the two who had bilateral congenital cataracts
removed), AC and GH (who had trauma-induced cataracts removed and were close
in age to RS and HB), performed a spatial grouping task based on geometric
cues ( Dehaene et al., 2006 ) in which they are shown six images–five images
depicting a specific geometric concept, and one outlier which does not abide
by the given regularity (for example, right angles, or parallel lines). The
children were asked to identify the outlier among the given geometric groups
(see, for instance, Figure 1E ).
### 2.5. Cross-modal object recognition
RS, HB, and IG were also tested for cross-modal object recognition. During
this task, they were asked to feel a 3D geometrically shaped wooden shape
(store-bought generic wooden blocks) they had never been exposed to before
(using touch alone–without seeing the shape as it was placed in a black,
opaque bag) corresponding to some of the shapes in a geometrical cues task
(see below). They were asked to look at one shape and report whether it was
the same or different from the shape they were touching; then, to match among
alternatives: look at two shapes and point to the one that matched the tactile
shape they were touching ( Figure 1C –the same wooden shapes they touched
were placed on a table in front of them). This task was repeated twice: once
using 3D real shapes for visual matching; once using 2D figures of the same
shapes presented on the computer.
### 2.6. Visual illusions
These three children were also tested on their perception of visual illusions.
The children were presented with classic visual illusions: Length illusions:
the Muller-Lyer (1889) illusion, the vertical-horizontal illusion (
Künnapas, 1955 ), and the Ponzo (1911) , Size illusions: Delboeuf (1865)
and Ebbinghaus (1902) illusions. In the length and depth illusions, the
children were asked whether one of the two lines appeared to be longer, while
in size illusions, they were asked whether one of the two circles looked
bigger (see Figure 2 ).
FIGURE 2
Figure 2. The single subject susceptibility to visual illusions. V represents
the subject’s susceptibility to the illusion, and X means that the subject was
not susceptible to the illusion.
## 3\. Results
### 3.1. Binocular rivalry
The two children with bilateral congenital cataracts removed (RS and HB) did
not show binocular rivalry despite reporting that they accurately saw each
image with the two eyes separately, meaning that they did not see the two
images alternating at any point of the task. IG, who had a congenital cataract
in one eye removed, did not report binocular rivalry. AC had a unilateral
trauma-induced cataract removed, lacked color perception in the eye, and did
not show binocular rivalry. The other children showed binocular rivalry when
tested 4–6 days after surgery.
### 3.2. Depth perception with the Brock string task
If one has binocular depth perception, they will see two lines crossing
instead of only one line after some time. The two children with bilateral
congenital cataracts removed (RS and HB) had no binocular depth perception.
Four of the five children with unilateral trauma-induced cataract removals did
have depth perception. IG, who had a congenital cataract in one eye removed,
did not have depth perception during the task.
### 3.3. Spatial grouping based on geometric cues
RS and HB (who had bilateral congenital cataracts removed), compared to AC and
GH, who had unilateral trauma-induced cataracts removed, performed this task.
Correct identification of the outlier was considered to be a “success.” All
the children tested had no or minimal prior schooling. The results showed that
RS and HB (congenital cataracts) outperformed AC and GH on this task with an
average success of 53% vs. 38%, much higher than the chance level of 16.6%. Of
course, it is difficult to reach generalized conclusion with such a low number
of subjects and trials, given the nature of this field research ( Figures 3
, 4 ).
FIGURE 3
Figure 3. The single subject average results on the spatial grouping task
based on geometric cues from Dehaene et al. (2006) (chance level is 16.6% in
these tasks).
FIGURE 4
Figure 4. The single subject grand average success on the spatial grouping
task.
### 3.4. Cross-modal object recognition
RS and HB (who had bilateral congenital cataracts removed), and IG (who had a
unilateral congenital cataract removed), underwent testing for cross-modal
object recognition. If the child correctly pointed to the visual shape that
matched the tactile shape they were touching, it was considered a “success.”
When tested 4–6 days after surgery, the children after bilateral cataract
removals showed very high accuracy in both the 2D and the 3D conditions. RS
and HB each succeeded in 9/10 trials with an accuracy of 90% (much higher than
the 50% chance level), and IG succeeded in 6/10 with an accuracy of 60%.
### 3.5. Visual illusions
A total of 4–6 days after surgery, RS, HB, and IG were tested on visual
illusions. RS and HB (who had bilateral congenital cataracts removed) showed
higher susceptibility to length illusions (Muller-Lyer, Vertical-Horizontal,
and Ponzo) than to size illusions (Ebbinghaus, Delboeouf). This test was
binary. Either the child perceived the illusion or not. Higher susceptibility,
in this case, refers to the fact that the children were influenced more by the
length illusions than the size illusions (as seen in Figure 2 ).
## 4\. Discussion
In this case study, eight children underwent a battery of numerous visual
tests and tasks in a challenging field setting, including the classic
binocular rivalry red/blue filtered glasses task and the Brock string task of
depth perception. Of the eight children who participated in the study, Two of
them were born with bilateral congenital cataracts, thereby experiencing true
unobscured sight for the first time in their lives only in the few days
preceding the study. One child was unilaterally congenitally blind, thereby
experiencing binocular vision for the first time in his life. The remaining
five were normally sighted children who lost vision in one eye due to trauma-
induced cataracts. As such, these children served as important control cases,
representing age-matched children with normal visual development during the
standard critical periods. The children with congenital cataracts were the
only ones in the group not to display either binocular rivalry or depth
perception on the Brock string task. In contrast, the other cases of trauma-
induced and later onset/short-term cataracts did show these abilities. Out of
the group, the two children with congenital cataract removals (bilateral and
unilateral) were also tested on visual illusions and cross-modal
correspondence. The children were susceptible to some depth illusions relying
on monocular cues, such as the Ponzo illusion. They showed high accuracy in
both the 2D and the 3D conditions of the cross-modal correspondences task (the
two with bilateral congenital cataracts showed nearly ceiling-level accuracy).
In addition, the two children with bilateral cataract removals were compared
to two children with trauma-induced cataract removals in a task of spontaneous
use of geometric cues. In this task, the children with bilateral congenital
cataract removals displayed an even higher success rate than their peers.
### 4.1. The results in the context of the theory of critical periods
Hubel and Wiesel’s Nobel prize-winning studies claim that sensory deprivation,
specifically of visual input in the early stages of life, would prevent the
rehabilitation of vision later in life ( Wiesel and Hubel, 1965 ; Hubel et
al., 1977 ; LeVay et al., 1980 ). On the one hand, the visual properties we
observed in the children who were deprived of vision during the critical
period (those who underwent bilateral or unilateral congenital cataract
removals) support the theory of critical periods (with regard to binocular
vision and depth perception in particular). But on the other hand, some
findings we observed in other tasks hint at a different interpretation
overall. It has been suggested that the unnatural, immediate increase in
visual acuity following congenital cataract removal does not follow the course
of events of vision acquisition in newborns, which in itself may delay the
proper encoding of visual information in the period directly following the
surgery ( Vogelsang et al., 2018 ).
In this study, when tested a few days after the surgery, the children who
underwent congenital cataract removal showed neither binocular rivalry nor
depth perception on the Brock string test. The obvious and clear implication
of this is that, as expressed by Bach-y-Rita (1972) , we see with our
brains, not with our eyes. Though the children’s eyes were no longer occluded,
and they achieved moderate-mild visual acuity (the WHO defines mild visual
acuity as worse than 6/12 to 6/18 and moderate visual acuity as worse than
6/18 to 6/60), their higher-level visual processing of the information was not
fully established.
Interestingly, on the visual illusion tasks in our study, the children who had
congenital cataracts removed were susceptible to some of the depth illusions
that rely on monocular depth cues, such as the Ponzo illusion. This might
indicate that at the time of testing, a few days after surgery, the children
were at an intermediate stage of visual recovery. This is further strengthened
by our findings concerning cross-modal object recognition and grouping based
on geometric cues, and by animal research that indicates sensory-motor
stimulation can promote recovery from visual deprivation ( Baroncelli et al.,
2010 ; Levelt and Hübener, 2012 ). The children’s success on these tasks
could represent the initial stages of development of a sense of 3D in the
visual domain. It is possible that recovery of bilateral depth is not as quick
as other aspects of visual recovery, compared to the results of the other
tasks, which the children were able to perform at a level similar to the
children who underwent trauma-induced cataract removal. This point is raised
with caution, as we lack information concerning the continued development of
the children’s vision at a later time. Yet we believe this indicates that
further research into the long-term visual recovery of children who have
undergone bilateral congenital cataract removal is particularly warranted.
### 4.2. A novel, objective method for determining congenital (early) vs.
late blindness
As described above, the children’s results on the binocular rivalry task and
the Brock string task are particularly interesting. Taken together, these two
tasks seem to be the primary distinguishing factor between congenitally blind
children and those who developed cataracts later in life. We propose utilizing
these two simple, straightforward tests as a method of making this
differentiation precisely in the field. This is particularly important for,
but not limited to, projects operating in low or middle-income countries where
access to medical records and documentation is less readily available or even
scarce ( Röder et al., 2021 ).
To promote and reliably conduct research involving people who have undergone
cataract removal or other surgeries and procedures for sight restoration in
childhood or even adulthood. Conducting research with these individuals
necessitates a very high degree of certainty that the study participants were
indeed devoid of vision from birth/very early life, specifically during the
critical periods ( Röder et al., 2021 ).
Following our study’s findings, we propose a novel method for retroactively
identifying individuals born congenitally blind. Potential subjects can be
screened on the binocular rivalry task and the Brock string task in
combination a few days after surgery. Our findings would allow the researcher
to confirm or disaffirm a congenital cataract diagnosis retroactively since
children with trauma-induced cataracts later in childhood could perform these
two specific tasks while children with congenital cataracts were not.
### 4.3. Replication and extension of previous studies on cross-modal
correspondence following congenital cataracts
The children’s results on the cross-modal object recognition tasks and the
spatial grouping based on geometric cues have significant scientific and
philosophical implications. Cross-modal object recognition tasks are
historically based on a philosophical thought experiment known as Molyneux’s
problem ( Ferretti and Glenney(eds), 2021 ). Molyneux, whose wife was blind,
pondered upon whether a blind person who could recognize objects by touch
would be able to recognize those same objects by vision, were his/her vision
miraculously restored. Molyneux pondered whether sighted and touch can or
cannot be linked immediately upon first sight Molyneux’s answer to his
proposed question was that they cannot, a stance backed by his friend Locke
(1847) and further agreed upon and expanded by George Berkley. Berkley (1709)
further stated that visual experience gained by the blind upon visual
restoration represents a “new set of ideas, perfectly distinct and different
from the former, and which can in no sort make themselves perceived by touch.”
This philosophical stance represents that of the empiricists, who opposed the
idea that there are innate amodal mechanisms in common between the senses and
that true sensory knowledge can only be gained through modality-specific
sensory experience.
Previous research conducted on children following congenital cataract removal
surgeries through Project Prakash found evidence that was consistent with
Molyneux’s idea in that the children could not immediately correspond between
what they saw and what they had felt ( Held et al., 2011 ). Yet they showed
that the children’s abilities to perform this matching improved rapidly,
developing within a few days. Another study by Chen et al. (2016) also
showed very rapid development of these abilities in a child who had undergone
cataract-removal surgery in under 2 days, concluding that the merging between
the senses is “prearranged.” Our results are consistent with these findings,
as the children in our study reached nearly top performance on this task when
tested a few days following their surgeries after having never encountered
these items in the visual domain. In addition, unlike Held et al. (2011) ,
the stimuli used in our study were naturally occurring geometric shapes,
further correlated to the task of spatial grouping by geometric cues (as
expanded upon below). Held et al. (2011) suggested that the performance
improvement may be due to their ability to create a three-dimensional visual
representation. Yet, the children in our study (who had congenital cataracts
removed) could not create three-dimensional representations at the stage at
which they could perform with very high accuracy on the cross-modal object
recognition task.
So while our findings are consistent with those of Held et al. (2011) who
show the development of this ability in such a consistently rapid way. We
interpret these findings differently with respect to the conclusion drawn with
respect to Molyneux’s problem. We claim that the extremely rapid development
of this ability, within days following surgery, could serve as evidence for
precisely the opposite interpretation, an uncovering of innate preexisting
connections between these senses ( Chen et al., 2016 ; Bola et al., 2017 ;
Maimon and Hemmo, 2022 ) or a re-calibration ( Gallagher, 2020 ). This
interpretation, which we believe is warranted by the findings, supports an
amodal understanding of brain development and structure. This is further
supported by the results of this study concerning spatial grouping based on
geometric cues. This interpretation is supported by prior research conducted
in our lab that has shown that the lateral-occipital tactile-visual area
(LOtv) is an area activated by visual and tactile exploration of objects (
Amedi et al., 2002 ) that can also be activated in the blind for processing
object shapes after training with a visual to auditory sensory substitution
device, indicating that this area is involved in the task of processing the
geometry and shape of objects, irrespective of the sensory modality through
which the information was conveyed ( Amedi et al., 2007 ).
### 4.4. Replication and expansion of previous studies on the spontaneous
emergence of geometry concepts in congenital cataracts
Spatial grouping tasks based on geometric cues have been used in prior
research to show that spontaneous geometry intuitions arise independently from
education in normally sighted Amazonian adults ( Dehaene et al., 2006 ).
This research was later expanded in our lab, showing that geometric knowledge
and reasoning develop irrespective of vision ( Heimler et al., 2021 ). This
study showed that both normally sighted blindfolded people and the
congenitally blind showed geometrical sense driven by touch alone. The results
of this current study further strengthen and elaborate on these findings, now
repeating the task for the first time via vision. The four children tested
on this task in our study had very little formal education, with RS having
never attended school at all and the other three children reaching up to
second-grade education. The findings showed that all four children (RS and HB,
who underwent surgery for bilateral congenital cataracts, and AC and GH, who
underwent surgery for unilateral trauma-induced cataracts) performed above
chance level, with RS and HB performing better than their peers who were born
with intact vision. These findings further support the amodal nature of the
brain, at least for geometry, and the innate preexisting links between the
senses. More generally, these findings support the revised “neuronal recycling
theory ( Dehaene, 2005 ; Dehaene and Cohen, 2007 )” that posits a task-
selective, sensory independent interpretation of specialization in the brain (
Striem-Amit et al. 2011 , 2012a ; Reich et al., 2012 ; Heimler et al.,
2015 ; Amedi et al., 2017 ). Under this interpretation, areas such as the
visual cortex are not “visual” per se as they do not undergo specialization
for vision but rather undergo specialization for performing a specific task
(where usually vision is the most accurate and easy way to perform the task)
and thereby can be activated by corresponding information delivered through
other senses. For example, the Lateral Occipital Cortex (LOC), commonly
correlated with visual object and shape recognition, could be recruited for
processing 3D geometric shapes, irrespective of the sensory modality through
which the information was provided, as was indeed shown in Amedi et al.
(2001) .
Another example would be the Visual Word Form Area (VWFA) commonly associated
with visual letter recognition. According to the task selective, sensory
independent interpretation, this area would be designated for the task of
symbol-to-phoneme conversion (independent of the visual modality), as
supported by Striem-Amit et al. (2012b) . There are many more such examples
of task selectivity as opposed to sensory-dependent organization. For a full
review, see Amedi et al. (2017) . Similar views of the brain as a-modal or
supramodal (see Pascual-Leone and Hamilton, 2001 ; Kupers and Ptito, 2011
; Ricciardi et al., 2014 ; Cecchetti et al., 2016 ) fit well with this
notion and theory.
### 4.5. Limitations and future directions
A practical limitation of the study pertains to the partial nature of the
children’s medical histories, which were reported by the parents, and the lack
of digitized medical data related to the children and their medical reports
(the post-operative surgical report was handwritten). Due to this partial or
illegible information, we did not, for example, have data concerning some of
the children’s pre-op visual acuity. Furthermore, as these results represent
the individual cases of the experiences of a number of children, the results
cannot be generalized. Yet, we feel that this research indicates several
future study directions. With respect to future directions, we suggest
implementing this battery of tests on children undergoing congenital cataract
removal, with data acquired pre-surgery, immediately following surgery, and
months after surgery. This way, the progressive development can be tracked,
further shedding light on the questions and issues we have discussed. In
addition, future research on the neural underpinnings of children’s visual
recovery in similar circumstances is warranted to further elucidate the link
between the behavioral and the neurological. As such, fMRI studies can be
conducted pre and post-surgery to investigate the mechanisms in the brain
corresponding to the visual experiences of the children following surgery.
This study presents a select few of the many lessons to be learned from these
cases regarding the deepest aspects of visual development specifically and the
profound interaction between the sensory experience and the brain more
generally.
## 5\. Conclusion
This study focused on the visual and geometry abilities of children who had
undergone cataract removal surgery at Quiha hospital in Ethiopia as part of
the Himalayan Cataract Project. The findings of the study reveal, first and
foremost, that out of the cohort of children, those with congenital cataracts
did not exhibit binocular rivalry, nor did they show depth perception when
tested with the Brock string test. These two tests clearly delineated the
congenitally blind children from the normally sighted at birth (who developed
cataracts later in life). As such, we novelly propose the utilization of these
two tests in retroactively confirming the blindness status of a child,
particularly in cases where medical history and records are lacking. In
addition, the current study replicates and expands upon previous studies
conducted on cross-modal correspondence following congenital cataract removal
in children. The children in this study reached nearly ceiling-level
performance on the cross-modal correspondence task when tested a mere few days
following their surgeries. Finally, this study strengthens the findings of
previous studies indicating that geometry concepts arise independently from
experience and education, thus supporting a task-selective, sensory-
independent interpretation of specialization and development in the brain.
## Data availability statement
The original contributions presented in this study are included in the
article/supplementary material, further inquiries can be directed to the
corresponding author.
## Ethics statement
Ethical approval was not provided for this study on human participants because
the study was conducted while the children were under the care and supervision
of the local Quiha Hospital medical staff, with the parents present. The
parents of all of the children signed written consent forms approving the
participation of the children in the study. Written informed consent to
participate in this study was provided by the participants’ legal
guardian/next of kin. Written informed consent was obtained from the
participant’s next of kind for the publication of any identifiable images or
data included in this article.
## Author contributions
AM: writing—original draft, review, and editing, conceptualization,
visualization, and project administration. ON and BH: conceptualization,
investigation, and visualization. AA: writing—original draft, review, and
editing, project administration, supervision, resources, conceptualization,
investigation, methodology, and funding acquisition. All authors contributed
to the article and approved the submitted version.
## Funding
This research was supported by an ERC Consolidator Grant (773121
NovelExperiSense) and a Horizon GuestXR (101017884) grant (both to AA).
## Acknowledgments
We wish to acknowledge and thank Dr. Geoffrey Tabin, co-founder and chairman
of the Himalayan Cataract Project, and Dr. Yonas Mitku, head of the
ophthalmology unit at Quiha General Hospital, who led the clinical operation
to restore vision and test the patients postsurgery. We would also like to
thank Prof. Stanislas Dehaene for providing us with material to test spatial
grouping based on geometric cues.
## Conflict of interest
The authors declare that the research was conducted in the absence of any
commercial or financial relationships that could be construed as a potential
conflict of interest.
## Publisher’s note
All claims expressed in this article are solely those of the authors and do
not necessarily represent those of their affiliated organizations, or those of
the publisher, the editors and the reviewers. Any product that may be
evaluated in this article, or claim that may be made by its manufacturer, is
not guaranteed or endorsed by the publisher.
## References
Abboud, S., Maidenbaum, S., Dehaene, S., and Amedi, A. (2015). A number-form
area in the blind. Nat. Commun. 6, 1–9. doi: 10.1038/ncomms7026
PubMed Abstract | CrossRef Full Text | Google Scholar
Amedi, A., Floel, A., Knecht, S., Zohary, E., and Cohen, L. G. (2004).
Transcranial magnetic stimulation of the occipital pole interferes with verbal
processing in blind subjects. Nat. Neurosci. 7, 1266–1270. doi:
10.1038/nn1328
PubMed Abstract | CrossRef Full Text | Google Scholar
Amedi, A., Hofstetter, S., Maidenbaum, S., and Heimler, B. (2017). Task
selectivity as a comprehensive principle for brain organization. Trends Cogn.
Sci. 21, 307–310. doi: 10.1016/j.tics.2017.03.007
PubMed Abstract | CrossRef Full Text | Google Scholar
Amedi, A., Jacobson, G., Hendler, T., Malach, R., and Zohary, E. (2002).
Convergence of visual and tactile shape processing in the human lateral
occipital complex. Cerebr. Cortex 12, 1202–1212. doi:
10.1093/cercor/12.11.1202
PubMed Abstract | CrossRef Full Text | Google Scholar
Amedi, A., Malach, R., Hendler, T., Peled, S., and Zohary, E. (2001). Visuo-
haptic object-related activation in the ventral visual pathway. Nat.
Neurosci. 4, 324–330. doi: 10.1038/85201
PubMed Abstract | CrossRef Full Text | Google Scholar
Amedi, A., Merabet, L. B., Bermpohl, F., and Pascual-Leone, A. (2005). The
occipital cortex in the blind: lessons about plasticity and vision. Curr.
Direct. Psychol. Sci. 14, 306–311. doi: 10.1111/j.0963-7214.2005.00387.x
CrossRef Full Text | Google Scholar
Amedi, A., Raz, N., Pianka, P., Malach, R., and Zohary, E. (2003). Early
‘visual’ cortex activation correlates with superior verbal memory performance
in the blind. Nat. Neurosci. 6, 758–766. doi: 10.1038/nn1072
PubMed Abstract | CrossRef Full Text | Google Scholar
Amedi, A., Stern, W. M., Camprodon, J. A., Bermpohl, F., Merabet, L., Rotman,
S., et al. (2007). Shape conveyed by visual-to-auditory sensory substitution
activates the lateral occipital complex. Nat. Neurosci. 10, 687–689. doi:
10.1038/nn1912
PubMed Abstract | CrossRef Full Text | Google Scholar
Aslin, R. N., and Banks, M. S. (1978). “Early visual experience in humans:
evidence for a critical period in the development of binocular vision,” in
Psychology: From Research to Practice , eds H. L. Pick, H. W. Leibowitz, J.
E. Singer, A. Steinschneider, and H. W. Stevenson (Boston, MA: Springer). doi:
10.1007/978-1-4684-2487-4_14
CrossRef Full Text | Google Scholar
Bola, Ł., Zimmermann, M., Mostowski, P., Jednoróg, K., Marchewka, A.,
Rutkowski, P., et al. (2017). Task-specific reorganization of the auditory
cortex in deaf humans. Proc. Natl. Acad. Sci. U.S.A. 114, E600–E609.
Google Scholar
Bach-y-Rita, P. (1972). Brain Mechanisms in Sensory Substitution. Cambridge,
MA: Academic Press.
Google Scholar
Baroncelli, L., Sale, A., Viegi, A., Vetencourt, J. F. M., De Pasquale, R.,
Baldini, S., et al. (2010). Experience-dependent reactivation of ocular
dominance plasticity in the adult visual cortex. Exp. Neurol. 226, 100–109.
doi: 10.1016/j.expneurol.2010.08.009
PubMed Abstract | CrossRef Full Text | Google Scholar
Bedny, M., Pascual-Leone, A., Dodell-Feder, D., Fedorenko, E., and Saxe, R.
(2011). Language processing in the occipital cortex of congenitally blind
adults. Proc. Natl. Acad. Sci. U.S.A. 108, 4429–4434. doi:
10.1073/pnas.1014818108
PubMed Abstract | CrossRef Full Text | Google Scholar
Blake, R., and Logothetis, N. K. (2002). Visual competition. Nat. Rev.
Neurosci. 3, 13–21. doi: 10.1038/nrn701
PubMed Abstract | CrossRef Full Text | Google Scholar
Brant, A. R., Hinkle, J., Shi, S., Hess, O., Zubair, T., Pershing, S., et al.
(2021). Artificial intelligence in global ophthalmology: using machine
learning to improve cataract surgery outcomes at Ethiopian outreaches. J.
Cataract Refract. Surg. 47, 6–10. doi: 10.1097/j.jcrs.0000000000000407
PubMed Abstract | CrossRef Full Text | Google Scholar
Brock, F. W. (1955). The string as an aid to visual training. Vis. Train.
Work 4, 29–33.
PubMed Abstract | Google Scholar
Cecchetti, L., Kupers, R., Ptito, M., Pietrini, P., and Ricciardi, E. (2016).
Are supramodality and cross-modal plasticity the yin and yang of brain
development? From blindness to rehabilitation. Front. Syst. Neurosci. 10:89.
doi: 10.3389/fnsys.2016.00089
PubMed Abstract | CrossRef Full Text | Google Scholar
Chen, J., Wu, E., Chen, X., Zhu, L., Li, X., Thorn, F., et al. (2016). Rapid
integration of tactile and visual information by a newly sighted child. Curr.
Biol. 26, 1069–1074. doi: 10.1016/j.cub.2016.02.065
PubMed Abstract | CrossRef Full Text | Google Scholar
Dehaene, S. (2005). 8 Evolution of Human Cortical Circuits for Reading and
Arithmetic: The From monkey brain to human brain: A Fyssen Foundation
symposium. Cambridge, MA: MIT press. doi: 10.7551/mitpress/3136.001.0001
CrossRef Full Text | Google Scholar
Dehaene, S., and Cohen, L. (2007). Cultural recycling of cortical maps.
Neuron 56, 384–398. doi: 10.1016/j.neuron.2007.10.004
PubMed Abstract | CrossRef Full Text | Google Scholar
Dehaene, S., Izard, V., Pica, P., and Spelke, E. (2006). Core knowledge of
geometry in an Amazonian indigene group. Science 311, 381–384. doi:
10.1126/science.1121739
PubMed Abstract | CrossRef Full Text | Google Scholar
Delboeuf, F. J. (1865). Note sur certaines illusions d’optique: essai d’une
théorie psychophysique de la maniere dont l’oeil apprécie les distances et les
angles. Bull. l’Académie R. Sci. Lett. Beaux Arts Belgique 19, 195–216.
Google Scholar
Ebbinghaus, H. (1902). The Principles of Psychology. Leipzig: VEIT GmbH.
Google Scholar
Fawcett, S. L., Wang, Y. Z., and Birch, E. E. (2005). The critical period for
susceptibility of human stereopsis. Investig. Ophthalmol. Vis. Sci. 46,
521–525. doi: 10.1167/iovs.04-0175
PubMed Abstract | CrossRef Full Text | Google Scholar
Ferretti, G., and Glenney, B. (eds) (2021). Molyneux’s Question and the
History of Philosophy. Milton Park: Routledge. doi: 10.4324/9780429020377
PubMed Abstract | CrossRef Full Text | Google Scholar
Fine, I., Wade, A. R., Brewer, A. A., May, M. G., Goodman, D. F., Boynton, G.
M., et al. (2003). Long-term deprivation affects visual perception and cortex.
Nat. Neurosci. 6, 915–916. doi: 10.1038/nn1102
PubMed Abstract | CrossRef Full Text | Google Scholar
Gallagher, S. (2020). “No yes answers to Molyneux,” in Molyneux’s Question
and the History of Philosophy , eds G. Ferretti and B. Glenney (Milton Park:
Routledge), 235–249. doi: 10.4324/9780429020377-21
PubMed Abstract | CrossRef Full Text | Google Scholar
Gandhi, T., Kalia, A., Ganesh, S., and Sinha, P. (2015). Immediate
susceptibility to visual illusions after sight onset. Curr. Biol. 25,
R358–R359.
Google Scholar
Gillam, B. (1980). Geometrical illusions. Sci. Am. 242, 102–111. doi:
10.1038/scientificamerican0180-102
CrossRef Full Text | Google Scholar
Grałek, M., Kanigowska, K., and Seroczyńska, M. (2007). Cataract in
children–not only an ophthalmological problem. Medycyna Wieku Rozwojowego
11(2 Pt 2), 227–230.
PubMed Abstract | Google Scholar
Heimler, B., and Amedi, A. (2020). Are critical periods reversible in the
adult brain? Insights on cortical specializations based on sensory deprivation
studies. Neurosci. Biobehav. Rev. 116, 494–507.
Google Scholar
Heimler, B., Behor, T., Dehaene, S., Izard, V., and Amedi, A. (2021). Core
knowledge of geometry can develop independently of visual experience.
Cognition 212:104716. doi: 10.1016/j.cognition.2021.104716
PubMed Abstract | CrossRef Full Text | Google Scholar
Heimler, B., Striem-Amit, E., and Amedi, A. (2015). Origins of task-specific
sensory-independent organization in the visual and auditory brain:
neuroscience evidence, open questions and clinical implications. Curr. Opin.
Neurobiol. 35, 169–177. doi: 10.1016/j.conb.2015.09.001
PubMed Abstract | CrossRef Full Text | Google Scholar
Heimler, B., Weisz, N., and Collignon, O. (2014). Revisiting the adaptive and
maladaptive effects of crossmodal plasticity. Neuroscience 283, 44–63. doi:
10.1016/j.neuroscience.2014.08.003
PubMed Abstract | CrossRef Full Text | Google Scholar
Held, R., Ostrovsky, Y., de Gelder, B., Gandhi, T., Ganesh, S., Mathur, U., et
al. (2011). The newly sighted fail to match seen with felt. Nat. Neurosci.
14, 551–553. doi: 10.1038/nn.2795
PubMed Abstract | CrossRef Full Text | Google Scholar
Hubel, D. H., and Wiesel, T. N. (1963). Shape and arrangement of columns in
cat’s striate cortex. J. Physiol. 165:559. doi:
10.1113/jphysiol.1963.sp007079
PubMed Abstract | CrossRef Full Text | Google Scholar
Hubel, D. H., and Wiesel, T. N. (1970). The period of susceptibility to the
physiological effects of unilateral eye closure in kittens. J. Physiol. 206,
419–436. doi: 10.1113/jphysiol.1970.sp009022
PubMed Abstract | CrossRef Full Text | Google Scholar
Hubel, D. H., Wiesel, T. N., LeVay, S., Barlow, H. B., and Gaze, R. M. (1977).
Plasticity of ocular dominance columns in monkey striate cortex. Philos.
Trans. R. Soc. Lond. B Biol. Sci. 278, 377–409. doi: 10.1098/rstb.1977.0050
PubMed Abstract | CrossRef Full Text | Google Scholar
Künnapas, T. M. (1955). “An analysis of the” vertical-horizontal illusion. J.
Exp. Psychol. 49:134. doi: 10.1037/h0045229
CrossRef Full Text | Google Scholar
Kupers, R., and Ptito, M. (2011). Insights from darkness: what the study of
blindness has taught us about brain structure and function. Prog. Brain Res.
192, 17–31. doi: 10.1016/B978-0-444-53355-5.00002-6
PubMed Abstract | CrossRef Full Text | Google Scholar
Leffler, C. T., Schwartz, S. G., Peterson, E., Couser, N. L., and Salman,
A.-R. (2021). The First Cataract Surgeons in the British Isles. Am. J.
Ophthalmol. 230, 75–122. doi: 10.1016/j.ajo.2021.03.009
PubMed Abstract | CrossRef Full Text | Google Scholar
LeVay, S., Wiesel, T. N., and Hubel, D. H. (1980). The development of ocular
dominance columns in normal and visually deprived monkeys. J. Comp. Neurol.
191, 1–51. doi: 10.1002/cne.901910102
PubMed Abstract | CrossRef Full Text | Google Scholar
Levelt, C. N., and Hübener, M. (2012). Critical-period plasticity in the
visual cortex. Annu. Rev. Neurosci. 35, 309–330. doi: 10.1146/annurev-
neuro-061010-113813
PubMed Abstract | CrossRef Full Text | Google Scholar
Levelt, W. J. (1965). On Binocular Rivalry. Doctoral dissertation. Assen:
Van Gorcum Assen.
Google Scholar
Locke, J. (1847). An Essay Concerning Human Understanding. Philadelphia, PA:
Kay & Troutman.
Google Scholar
Maimon, A., and Hemmo, M. (2022). Does Neuroplasticity Support the Hypothesis
of Multiple Realizability? Philos. Sci. 89, 107–127. doi:
10.1017/psa.2021.16
CrossRef Full Text | Google Scholar
Marlair, C., Pierret, E., and Crollen, V. (2021). Geometry intuitions without
vision? A study in blind children and adults. Cognition 216:104861. doi:
10.1016/j.cognition.2021.104861
PubMed Abstract | CrossRef Full Text | Google Scholar
McGoldrick, D. (1991). The United Nations convention on the rights of the
child. Int. J. Law Policy Fam. 5, 132–169. doi: 10.1093/lawfam/5.2.132
CrossRef Full Text | Google Scholar
Miller, S. M., Liu, G. B., Ngo, T. T., Hooper, G., Riek, S., Carson, R. G., et
al. (2000). Interhemispheric switching mediates perceptual rivalry. Curr.
Biol. 10, 383–392.
Google Scholar
Muller-Lyer, F. C. (1889). Optische urteilstauschungen. Arch. Anatomie
Physiol. Physiol. Abteilung 2, 263–270.
Google Scholar
Ostrovsky, Y., Andalman, A., and Sinha, P. (2006). Vision following extended
congenital blindness. Psychol. Sci. 17, 1009–1014. doi:
10.1111/j.1467-9280.2006.01827.x
PubMed Abstract | CrossRef Full Text | Google Scholar
Pascual-Leone, A., and Hamilton, R. (2001). The metamodal organization of the
brain. Prog. Brain Res. 134, 427–445. doi: 10.1016/S0079-6123(01)34028-1
CrossRef Full Text | Google Scholar
Pettigrew, J. D. (2001). Searching for the switch: neural bases for perceptual
rivalry alternations. Brain Mind 2, 85–118. doi: 10.1023/A:1017929617197
CrossRef Full Text | Google Scholar
Ponzo, M. (1911). Intorno Ad Alcune Illusioni Nel Campo Delle Sensazioni
Tattili Sull’illusione Di Aristotele e Fenomeni Analoghi. Berlin: Wilhelm
Engelmann.
Google Scholar
Reich, L., Maidenbaum, S., and Amedi, A. (2012). The brain as a flexible task
machine: implications for visual rehabilitation using noninvasive vs. invasive
approaches. Curr. Opin. Neurol. 25, 86–95. doi: 10.1097/WCO.0b013e32834ed723
PubMed Abstract | CrossRef Full Text | Google Scholar
Reich, L., Szwed, M., Cohen, L., and Amedi, A. (2011). A ventral visual stream
reading center independent of visual experience. Curr. Biol. 21, 363–368.
doi: 10.1016/j.cub.2011.01.040
PubMed Abstract | CrossRef Full Text | Google Scholar
Ricciardi, E., Bonino, D., Pellegrini, S., and Pietrini, P. (2014). Mind the
blind brain to understand the sighted one! Is there a supramodal cortical
functional architecture? Neurosci. Biobehav. Rev. 41, 64–77. doi:
10.1016/j.neubiorev.2013.10.006
PubMed Abstract | CrossRef Full Text | Google Scholar
Röder, B., Kekunnaya, R., and Guerreiro, M. J. (2021). Neural mechanisms of
visual sensitive periods in humans. Neurosci. Biobehav. Rev. 120, 86–99.
doi: 10.1016/j.neubiorev.2020.10.030
PubMed Abstract | CrossRef Full Text | Google Scholar
Sinha, P. (2013). Once blind and now they see. Sci. Am. 309, 48–55. doi:
10.1038/scientificamerican0713-48
PubMed Abstract | CrossRef Full Text | Google Scholar
Sinha, P., Chatterjee, G., Gandhi, T., and Kalia, A. (2013). Restoring vision
through “Project Prakash”: the opportunities for merging science and service.
PLoS Biol. 11:e1001741. doi: 10.1371/journal.pbio.1001741
PubMed Abstract | CrossRef Full Text | Google Scholar
Siu, C. R., and Murphy, K. M. (2018). The development of human visual cortex
and clinical implications. Eye Brain 10, 25–36. doi: 10.2147/EB.S130893
PubMed Abstract | CrossRef Full Text | Google Scholar
Striem-Amit, E., Bubic, A., and Amedi, A. (2012a). “Neurophysiological
mechanisms underlying plastic changes and rehabilitation following sensory
loss in blindness and deafness,” in The Neural Bases of Multisensory
Processes , eds M. M. Murray and M. T. Wallace (Boca Raton, FL: CRC
Press/Taylor & Francis). doi: 10.1201/b11092-27
PubMed Abstract | CrossRef Full Text | Google Scholar
Striem-Amit, E., Cohen, L., Dehaene, S., and Amedi, A. (2012b). Reading with
sounds: sensory substitution selectively activates the visual word form area
in the blind. Neuron 76, 640–652. doi: 10.1016/j.neuron.2012.08.026
PubMed Abstract | CrossRef Full Text | Google Scholar
Striem-Amit, E., Dakwar, O., Reich, L., and Amedi, A. (2011). The large-scale
organization of “visual” streams emerges without visual experience. Cerebr.
Cortex 22, 1698–1709. doi: 10.1093/cercor/bhr253
PubMed Abstract | CrossRef Full Text | Google Scholar
Thomas, S. (2011). Project prakash: challenging the critical period:
association of research in vision and ophthalmology national meeting. Yale J.
Biol. Med. 84, 483–485.
PubMed Abstract | Google Scholar
Vogelsang, L., Gilad-Gutnick, S., Ehrenberg, E., Yonas, A., Diamond, S., Held,
R., et al. (2018). Potential downside of high initial visual acuity. Proc.
Natl. Acad. Sci. U.S.A. 115, 11333–11338. doi: 10.1073/pnas.1800901115
PubMed Abstract | CrossRef Full Text | Google Scholar
Wade, N. J. (1998). Early studies of eye dominances. Lateral. Asymmetr. Body
Brain Cogn. 3, 97–108. doi: 10.1080/713754296
PubMed Abstract | CrossRef Full Text | Google Scholar
Welling, J., Newick, E., and Tabin, G. (2013). The economic impact of cataract
surgery in a remote Ghanaian village three years after surgical intervention.
Investig. Ophthalmol. Vis. Sci. 54, 4396–4396.
Google Scholar
Wells, H. G. (1921). The Country of the Blind. New York, NY: Appeal
Publishing Company.
Google Scholar
Wiesel, T. N., and Hubel, D. H. (1963). Effects of visual deprivation on
morphology and physiology of cells in the cat’s lateral geniculate body. J.
Neurophysiol. 26, 978–993.
Google Scholar
Wiesel, T. N., and Hubel, D. H. (1965). Extent of recovery from the effects of
visual deprivation in kittens. J. Neurophysiol. 28, 1060–1072. doi:
10.1152/jn.1965.28.6.1060
PubMed Abstract | CrossRef Full Text | Google Scholar
Wiesel, T. N., and Hubel, D. H. (1974). Ordered arrangement of orientation
columns in monkeys lacking visual experience. J. Comp. Neurol. 158, 307–318.
Google Scholar
World Health Organization [WHO] (2021). Blindness and Vision Impairment.
Geneva: World Health Organization.
Google Scholar
Keywords : vision restoration, sensory perception, sensory development,
visual perception, cataract removal, visual development, geometry, 3D
perception
Citation: Maimon A, Netzer O, Heimler B and Amedi A (2023) Testing geometry
and 3D perception in children following vision restoring cataract-removal
surgery. Front. Neurosci. 16:962817. doi: 10.3389/fnins.2022.962817
Received: 06 June 2022; Accepted: 19 December 2022;
Published: 11 January 2023.
Edited by:
Maurice Ptito , University of Montreal, Canada
Reviewed by:
Laurence Dricot , Université Catholique de Louvain, Belgium
Stuart Trenholm , McGill University, Canada
Copyright © 2023 Maimon, Netzer, Heimler and Amedi. This is an open-access
article distributed under the terms of the Creative Commons Attribution
License (CC BY) . The use, distribution or reproduction in other forums is
permitted, provided the original author(s) and the copyright owner(s) are
credited and that the original publication in this journal is cited, in
accordance with accepted academic practice. No use, distribution or
reproduction is permitted which does not comply with these terms.
*Correspondence: Amber Maimon, [email protected]
Disclaimer: All claims expressed in this article are solely those of the
authors and do not necessarily represent those of their affiliated
organizations, or those of the publisher, the editors and the reviewers. Any
product that may be evaluated in this article or claim that may be made by its
manufacturer is not guaranteed or endorsed by the publisher.
# Footer
* Guidelines
* Author guidelines
* Editor guidelines
* Policies and publication ethics
* Fee policy
* Explore
* Articles
* Research Topics
* Journals
* Outreach
* Frontiers Forum
* Frontiers Policy Labs
* Frontiers for Young Minds
* Connect
* Help center
* Emails and alerts
* Contact us
* Submit
* Career opportunities
Follow us
© 2024 Frontiers Media S.A. All rights reserved
Privacy policy | Terms and conditions
| biology | 2149922 | https://no.wikipedia.org/wiki/%C3%98yebevegelse%20i%20lesing | Øyebevegelse i lesing | Øyenbevegelse i lesing innebærer visuell behandling av skriftlig tekst. Dette ble beskrevet av den franske øyelege Louis Émile Javal på slutten av 1800-tallet. Han rapporterte at øynene ikke beveger seg kontinuerlig langs en tekstlinje, men gjør korte, raske bevegelser (sakkader) blandet med korte stopp. Javals observasjoner av øyenbevegelser ble gjort helt manuelt, som følge av fravær av teknologi. Fra slutten av 1800-tallet til midten av 1900-tallet brukte forskere tidlig sporingsteknologi til hjelp med observasjon, i et forskningsmiljø som vektla måling av mennelskelig adferd og ferdigheter for utdanningsformål. Det meste av grunnleggende kunnskap om øyenbevegelse ble oppdaget i denne perioden. Siden midten av det 20. århundre har det vært tre store endringer: utviklingen av utstyr for ikke-invasiv øyebevegelses sporing; innføring av datateknologi for å øke dette utstyrets evne til å hente, registrere og behandle den enorme mengden data som øyebevegelsen genererer; og fremveksten av kognitiv psykologi som en teoretisk og metodisk ramme for å observere lese prosesser. Sereno & Rayner (2003) mente at den beste tilnærmingen for å oppdage umiddelbare tegn på ordgjenkjenning er gjennom opptak av øyenbevegelse og registrering av hjernens respons (ERP)
Historie
Fram til andre halvdel av 1800-tallet hadde forskere tre metoder til å undersøke øyets bevegelse. Den første, uten hjelp observasjonen, ga bare små mengder data som ville bli ansett som upålitelige etter dagens vitenskapelige standarder. Denne mangelen på pålitelighet skyldes at øyebevegelsen skjer ofte, raskt og i små vinkler, i den grad at det er umulig for en forsker å oppfatte og registrere dataene fullstendig og nøyaktig uten teknisk hjelp. Den andre metoden var selvobservasjon, som nå anses å være tvilsom i en vitenskapelig sammenheng. Til tross for dette, ser det ut til at noe kunnskap er blitt tilført gjennom visuell egenobservasjon . Ibn al Haytham, en lege i det 11. århundre i Egypt, har for eksempel skrevet om lesing i form av en rekke raske bevegelser og at han har innsett at leserne bruker både sidesyn og sentralt syn
Leonardo da Vinci (1452-1519) var kanskje den første i Europa som oppdaget visse spesielle optiske egenskaper i øyet. Han tilegnet seg kunnskapen delvis gjennom selvobservasjon, men hovedsakelig gjennom en prosess som kunne beskrives som optisk modellering. Basert på disseksjon av det menneskelige øyet gjorde han eksperimenter med vannfylte krystallkuler. Han skrev: "Det menneskelig øyets virkemåte, ...ble beskrevet av et stort antall forfattere på en viss måte. Men jeg fant ut at det virket på en helt annen måte"
Hans viktigste eksperimentelle funn var at det bare er tydelig og klart syn ved "synslinjen", den optiske aksen som ender ved fovea. Selv om han ikke brukte akkurat disse ordene, er han den første som skiller mellom fovea centralis (hvor observatøren fokuserer på objektet av interesse) og sidesyn. Leonardo visste imidlertid ikke at det var netthinnen som fanget opp synsnntrykkene, han trodde fortsatt at linsen var synsorganet.
Det er ikke dokumentert forskning på øyenbevegelse før tidlig på 1800-tallet. Utfordringen lå først i å beskrive øyet som et fysiologisk og mekanisk bevegelig objekt, det første forsøket ble gjort av Hermann von Helmholtz, i hans store verk Handbook of physiological optics (1866). Den fysiologiske tilnærmingen ble gradvis erstattet av interesse for de psykologisk aspektene av visuell input.
De neste tiårene var det flere, mer omfattende forsøk på å tolke øyenbevegelsen, inkludert en påstand om at meningsfull tekst krever færre stopp i lesingen, enn tilfeldige bokstavstrenger. I 1879 brukte den franske øyelegen Louis Émile Javal et speil på en side av en siden i en bok, for å observere øyet bevegelse i stille lesning, og fant ut at dette innebærer en rekke diskontinuerlige individuelle bevegelser. Dette fenomenet kalte han sakkader. I 1898 brukte Erdmann & Dodge et håndspeil for å estimere gjennomsnittlig fiksasjonstid og sakkadelengde med overraskende nøyaktighet.
Tidlig sporingsteknologi
Øyesporingsapparat er et verktøy som er laget for å måle bevegelser i øyet, samt hodebevegelser. De første apparatene som ble laget for å spore øyenbevegelsen måtte enten ha en mekanisk forbindelse mellom deltaker og apparatet, eller det ble brukt lys eller annen form for elektromagnetisk energi som ble rettet mot deltakerens øyne. I 1883 var Lamare den første til å bruke en mekanisk forbindelse ved å plassere en stump nål på deltakernes øvre øyelokk. Nålen opptar lyden som produseres av hver sakkade og sender den som et svakt klikk til forsøkspersonens øre gjennom et forsterkende membran og et gummirør. Begrunnelsen for å gjøre det på denne måten var at det var enklere å oppfatte sakkader ved hjelp av lyd. I 1889 oppfant Edmund B. Delabarre et system for å registrere øyets bevegelse direkte på et roterende trommel ved hjelp av en stylus med direkte mekanisk tilkobling til hornhinnen. Andre enheter som involverer fysisk kontakt med øyen overflaten ble utviklet og brukt fra slutten av 1800-tallet til slutten av 1920-tallet; disse inkluderte gjenstander som gummiballonger og øyetapper.
Mekaniske metoder medførte tre alvorlige ulemper: unøyaktighet på grunn av brudd den fysiske tilkoblingen, et betydelige ubehag som deltakerne ble påført som følge av den direkte mekaniske tilkoblingen (og dermed store vanskeligheter med å overtale folk til å delta), og spørsmål om forskningens gyldighet, siden deltakernes opplevelse av lesing i forsøk var veldig forskjellig fra leseopplevelsen under normale omstendigheter. Til tross for disse ulempene ble mekaniske apparater brukt i øyenbevegelsesforskning godt inn i det 20. århundre.
Etter hvert ble det gjort flere forsøk på å løse problemene og ulempene ved mekaniske metoder. En løsning var å bruke elektromagnetisk energi, i stedet for en mekanisk forbindelse. I "Dodge-teknikken" ble en lysstråle rettet mot hornhinnen, ved hjelp av et system med linser, for deretter å registrere resultatet på en bevegelig fotografisk plate. Erdmann & Dodge brukte denne teknikken, og fant ut at det er liten eller ingen oppfatning under sakkader, et funn som senere ble bekreftet av Utall & Smith ved hjelp av mer sofistikert utstyr. Den fotografiske platen i Dodge-teknikken ble snart erstattet med et filmkamera, men fortsatt var registreringen unøyaktig, på grunn av vanskeligheten med å holde alle deler av utstyret perfekt justert gjennom testene. I tillegg var det vanligvis nødvendig å holde deltakerens hode i ro ved hjelp av en klemme eller en bitekloss.
I 1922 var Schott med i utviklingen av det som kalles elektro-okulografi (EOG), en teknikk for å måle corneo-retinale ståpotensialet som finnes mellom forsiden og baksiden av det menneskelige øyet. Elektroder kan dekkes med spesiell kontaktpasta før de plasseres på huden. Så det er nå unødvendig å gjøre snitt i pasientens hud. En vanlig misforståelse om EOG er at målt potensial er elektromyogrammet av øyenmuskler. Faktisk er det bare projisering av øye dipol til huden, fordi høyere frekvenser, som tilsvarer EMG, filtreres ut. EOG har gitt betydelige forbedringer i nøyaktighet og pålitelighet, noe som forklarer at forskere har fortsatt å bruke den i mange tiår.
Moderne sporing av øyenbevegelse
Fire store kognitive systemer er involvert i øyes bevegelse under lesing: språkbehandling, oppmerksomhet, syn og oculomotorisk kontroll. Apperater for sporing av øyets bevegelse sender infrarødt lys inn i av øyet, og registrerer refleksjonen på øyet for å avgjøre blikkets plassering. Med denne teknikken kan blikkets begelse over en skjerm registreres nøyaktig. Wang (2011) nevnte at videobasert øye-sporing som bruker vkameraer til å registrere øyeposisjonen - opptak av pupillens utvidelse og øyebevegelse - kan brukes til å undersøke hvordan fiksasjoner, sakkader og pupillens utvidelse er relatert til informasjonen på skjermen og adferdsvalg. Ifølge Wang (2011:185), "å forstå forholdet mellom disse observasjonene kan hjelpe oss til å forstå hvordan menneskelig atferd i økonomien kan påvirkes av hvilken informasjon folk mottar, hvor oppmerksomheten er fokusert, hvilken følelsesmessig tilstand de er i, og til og med hvilken hjerneaktivitet som foregår. Dette er fordi fiksasjoner og sakkader (sammenholdt med informasjon som vises på skjermen) indikerer hvordan folk oppsøker informasjon (og hva de ser), tidsintervallene på fiksasjoner indikerer oppmerksomhet, og pupillenes utvidelse indikerer følelser, opphisselse, stress, smerte eller kognitiv belastning".
Sakkader
De dyktige leserne beveger øynene sine når de leser, i gjennomsnitt hvert fjerdedels sekund. I løpet av tiden øyet er fiksert, blir ny informasjon oppfattet i prosessystemet. Selv om gjennomsnittlig fiksasjonstid er 200-250 ms (tusendeler av et sekund), er området fra 100 ms til over 500 ms. Avstanden øyet beveger seg i hver sakkade (eller kort rask bevegelse) er mellom 1 og 20 tegn med gjennomsnittet på 7-9 tegn. Sakkaden varer i 20-40 ms og i løpet av denne tiden blir synet undertrykt slik at ingen ny informasjon blir oppfattet. Det er betydelig variasjon i fiksasjoner (punktet en sakkade hopper til) og sakkader mellom lesere og selv for den samme personen som leser en enkelt tekst. De dyktige leserne gjør regresjoner tilbake til materiale som allerede er lest omtrent 15 prosent av tiden. Hovedforskjellen mellom raskere og langsommere lesere er at den siste gruppen konsekvent viser lengre gjennomsnittlig fiksasjonstid, kortere sakkader og flere regresjoner. Disse grunnleggende fakta om øyenbevegelse har vært kjent i nesten hundre år, men først nå nylig, har forskere begynt å se på sammenhengen mellom øyenbevegelsesadferd og kognitiv prosessering ved lesing.
Den nedre linjen av teksten simulerer synsskydigheten med de relative skarphetsprosentene. Vankeligheten med å gjenkjenne tekst øker med avstanden fra punktet i fokus.
Dysleksi
Personer med dysleksi har vanligvis en redusert lesehastighet, noe som kan ha mange forskjellige årsaker. Det finnes mange tiltak man kan gjøre for å prøve bøte på symptomene, avhengig av hvilken biologisk teori dysleksi er basert på. Èn slik ide er basert på magnosellulært underskudd, hvor Magnocellular veier er ukoordinert, noe som forårsaker å hoppe over, eller lese linjer på nytt.
Datamodeller for øyenbevegelse i lesing
Konkurranse-interaksjonsteori og SERIF legger vekt på oculomotoriske prosesser på lavt nivå i lesing, for eksempel hvordan ordlengden til det nåværende fikserte ordet og dets naboord påvirker sakkadeamplitude og latens (eller fikseringsvarighet). Reader, EMMA, E-Z Reader og SWIFT legger vekt på kognitive prosesser på høyere nivå som leksikalsk prosessering, ordfrekvens, ordanalyse eller ordforutsigbarhet.
Se også
Lesing
Øyesporing
Foveal
Referanser
Litteratur
Abadi, R. V. (2006). Vision and eye movements. Clinical and Experimental Optometry, 55–56.
Delabarre E.B. (1898) A method of recording eye-movements, Psychological Review 8, 572–74.
Engbert, R. & Kliegl, R. (2011) Parallel graded attention models of reading. The Oxford handbook of eye movements. Liversedge, S., Gilchrist, I., & Everling, S. (Eds.) Oxford University Press.
Erdmann B & Dodge R (1898) Psychologische Untersuchung über das Lesen auf experimenteller Grundlage, Niemeyer: Halle.
Finocchio, Dom; Preston, Karen L; Fuchs, Albert F. (1990). "Obtaining a quantitative measure of eye movements in human infants: A method of calibrating the electrooculogram". Vision Research 30(8): 1119–28. .
Heller D (1988) "On the history of eye movement recording" in Eye movement research: physiological and psychological aspects, Toronto: CJ Hogrefe, 37–51.
Helmholtz H (1866) Handbuch der physiologischen Optik, Voss: Hamburg.
Hunziker, H. (2006). Im Auge des Lesers: foveale und periphere Wahrnehmung – vom Buchstabieren zur Lesefreude [In the eye of the reader: foveal and peripheral perception – from letter recognition to the joy of reading] Transmedia Stäubli Verlag Zürich 2006, .
Javal, E. (1878) "Essai sur la physiologie de la lecture", in Annales d'ocullistique 80, 61–73.
Just, M.A., & Carpenter, P.A. (1980). A theory of reading: from eye fixations to comprehension. Psychological review, 87(4), 329.
Lamare, M. (1893) Des mouvements des yeux pendants la lecture, Comptes rendus de la société française d'ophthalmologie, 35–64.
Liu, Y.; Zhou, Z.; Hu, D. (2011). "Gaze independent brain-computer speller with covert visual search tasks". Clinical Neurophysiology 122(6): 1127–36. . Retrieved 1 November 2011.
McDonald, S. A., Carpenter, R. H. S., & Shillcock, R. C. (2005). An anatomically constrained, stochastic model of eye movement control in reading. Psychological review, 112(4), 814.
Nuthmann, A. (2014, September). Eye movements and visual cognition lecture 2 (University of Edinburgh, UK).
Rayner, K.; Foorman, B.; Perfetti, C.; Pesetsky, D. & Seidenberg, M. (2001). How psychological science informs the teaching of reading. Psychological Science in the Public Interest 2(2): 31–74.
Rayner, K.; Slattery, Timothy J; Belanger, Nathalie N. (2010). Eye movements, the perceptual span, and reading speed. Psychonomic Bulletin & Review 17(6): 834–39. . Retrieved 1 November 2011.
Rayner K. (1975). Eye movements, perceptual span, and reading disability, Annals of Dyslexia, 33(1), 163–73.
Rayner; K.; Pollatsek, J.; Alexander, B.(2005). Eye movements during reading. The science of reading: A handbook. [1-4051-1488-6 ]: Blackwell Publishing. pp. 79–97. (Hardcover); 978-1-4051-1488-2.
Reichle, E. (2011). Serial-attention models of reading. The Oxford handbook of eye movements. Liversedge, S., Gilchrist, I., & Everling, S. (Eds.) Oxford University Press.
Reichle, E.D., Rayner, K., & Pollatsek, A. (2003). The EZ Reader model of eye-movement control in reading: comparisons to other models. Behavioral and Brain Sciences, 26(04), 445–76.
Salvucci, D.D. (2001). An integrated model of eye movements and visual encoding. Cognitive Systems Research, 1(4), 201-220.
Schott E (1922) Über die Registrierung des Nystagmus und anderer Augenbewegungen vermittels des Saitengalvanometers, Deutsches Archiv für klinisches Medizin 140, 79–90.
Sereno, S.; Rayner, K. (2003). Measuring word recognition in reading: eye movements and event-related potentials. Trends in Cognitive Sciences, 7(11): 489–93.
Tecce, J.; Pok, L.J.; Consiglio, M.R.; O'Neil, J.L. (2005). Attention impairment in electrooculographic control of computer functions. International Journal of Psychophysiology, 55(2): 159–63. . Retrieved 1 November 2011.
Vitu, F., McConkie, G.W., Kerr, P., & O'Regan, J.K. (2001). Fixation location effects on fixation durations during reading: An inverted optimal viewing position effect. Vision research'', 41(25), 3513–33.
Wang, J. (2011). "Pupil dilation and eye-tracking." A handbook of process tracing methods for decision research: a critical review and user's guide: Society for Judgment and Decision Making Series. pp. 185–204. .
Yang, S.-N., & McConkie, G.W. (2001). Eye movements during reading: a theory of saccade initiation times. Vision Research, 41, 3567–85.
Motorikk
Øyet
Kognitiv vitenskap | norwegian_bokmål | 0.572038 |
3D_vision/Binocular_disparity.txt | Binocular disparity refers to the difference in image location of an object seen by the left and right eyes, resulting from the eyes’ horizontal separation (parallax). The mind uses binocular disparity to extract depth information from the two-dimensional retinal images in stereopsis. In computer vision, binocular disparity refers to the difference in coordinates of similar features within two stereo images.
A similar disparity can be used in rangefinding by a coincidence rangefinder to determine distance and/or altitude to a target. In astronomy, the disparity between different locations on the Earth can be used to determine various celestial parallax, and Earth's orbit can be used for stellar parallax.
Definition[edit]
Figure 1. Definition of binocular disparity (far and near).
Human eyes are horizontally separated by about 50–75 mm (interpupillary distance) depending on each individual. Thus, each eye has a slightly different view of the world around. This can be easily seen when alternately closing one eye while looking at a vertical edge. The binocular disparity can be observed from apparent horizontal shift of the vertical edge between both views.
At any given moment, the line of sight of the two eyes meet at a point in space. This point in space projects to the same location (i.e. the center) on the retinae of the two eyes. Because of the different viewpoints observed by the left and right eye however, many other points in space do not fall on corresponding retinal locations. Visual binocular disparity is defined as the difference between the point of projection in the two eyes and is usually expressed in degrees as the visual angle.
The term "binocular disparity" refers to geometric measurements made external to the eye. The disparity of the images on the actual retina depends on factors internal to the eye, especially the location of the nodal points, even if the cross section of the retina is a perfect circle. Disparity on retina conforms to binocular disparity when measured as degrees, while much different if measured as distance due to the complicated structure inside eye.
Figure 1: The full black circle is the point of fixation. The blue object lies nearer to the observer. Therefore, it has a "near" disparity dn. Objects lying more far away (green) correspondingly have a "far" disparity df. Binocular disparity is the angle between two lines of projection . One of which is the real projection from the object to the actual point of projection. The other one is the imaginary projection running through the nodal point of the fixation point.
In computer vision, binocular disparity is calculated from stereo images taken from a set of stereo cameras. The variable distance between these cameras, called the baseline, can affect the disparity of a specific point on their respective image plane. As the baseline increases, the disparity increases due to the greater angle needed to align the sight on the point. However, in computer vision, binocular disparity is referenced as coordinate differences of the point between the right and left images instead of a visual angle. The units are usually measured in pixels.
Tricking neurons with 2D images[edit]
Figure 2. Simulation of disparity from depth in the plane. (relates to Figure 1)
Brain cells (neurons) in a part of the brain responsible for processing visual information coming from the retinae (primary visual cortex) can detect the existence of disparity in their input from the eyes. Specifically, these neurons will be active, if an object with "their" special disparity lies within the part of the visual field to which they have access (receptive field).
Researchers investigating precise properties of these neurons with respect to disparity present visual stimuli with different disparities to the cells and look whether they are active or not. One possibility to present stimuli with different disparities is to place objects in varying depth in front of the eyes. However, the drawback to this method may not be precise enough for objects placed further away as they possess smaller disparities while objects closer will have greater disparities. Instead, neuroscientists use an alternate method as schematised in Figure 2.
Figure 2: The disparity of an object with different depth than the fixation point can alternatively be produced by presenting an image of the object to one eye and a laterally shifted version of the same image to the other eye. The full black circle is the point of fixation. Objects in varying depths are placed along the line of fixation of the left eye. The same disparity produced from a shift in depth of an object (filled coloured circles) can also be produced by laterally shifting the object in constant depth in the picture one eye sees (black circles with coloured margin). Note that for near disparities the lateral shift has to be larger to correspond to the same depth compared with far disparities. This is what neuroscientists usually do with random dot stimuli to study disparity selectivity of neurons since the lateral distance required to test disparities is less than the distances required using depth tests. This principle has also been applied in autostereogram illusions.
Computing disparity using digital stereo images[edit]
The disparity of features between two stereo images are usually computed as a shift to the left of an image feature when viewed in the right image. For example, a single point that appears at the x coordinate t (measured in pixels) in the left image may be present at the x coordinate t − 3 in the right image. In this case, the disparity at that location in the right image would be 3 pixels.
Stereo images may not always be correctly aligned to allow for quick disparity calculation. For example, the set of cameras may be slightly rotated off level. Through a process known as image rectification, both images are rotated to allow for disparities in only the horizontal direction (i.e. there is no disparity in the y image coordinates). This is a property that can also be achieved by precise alignment of the stereo cameras before image capture.
Computer algorithm[edit]
After rectification, the correspondence problem can be solved using an algorithm that scans both the left and right images for matching image features. A common approach to this problem is to form a smaller image patch around every pixel in the left image. These image patches are compared to all possible disparities in the right image by comparing their corresponding image patches. For example, for a disparity of 1, the patch in the left image would be compared to a similar-sized patch in the right, shifted to the left by one pixel. The comparison between these two patches can be made by attaining a computational measure from one of the following equations that compares each of the pixels in the patches. For all of the following equations, L and R refer to the left and right columns while r and c refer to the current row and column of either images being examined. d refers to the disparity of the right image.
Normalized correlation:
∑
∑
L
(
r
,
c
)
⋅
R
(
r
,
c
−
d
)
(
∑
∑
L
(
r
,
c
)
2
)
⋅
(
∑
∑
R
(
r
,
c
−
d
)
2
)
{\displaystyle {\frac {\sum {\sum {L(r,c)\cdot R(r,c-d)}}}{\sqrt {(\sum {\sum {L(r,c)^{2}}})\cdot (\sum {\sum {R(r,c-d)^{2}}})}}}}
Sum of squared differences:
∑
∑
(
L
(
r
,
c
)
−
R
(
r
,
c
−
d
)
)
2
{\displaystyle \sum {\sum {(L(r,c)-R(r,c-d))^{2}}}}
Sum of absolute differences:
∑
∑
|
L
(
r
,
c
)
−
R
(
r
,
c
−
d
)
|
{\displaystyle \sum {\sum {\left|L(r,c)-R(r,c-d)\right\vert }}}
The disparity with the lowest computed value using one of the above methods is considered the disparity for the image feature. This lowest score indicates that the algorithm has found the best match of corresponding features in both images.
The method described above is a brute-force search algorithm. With large patch and/or image sizes, this technique can be very time consuming as pixels are constantly being re-examined to find the lowest correlation score. However, this technique also involves unnecessary repetition as many pixels overlap. A more efficient algorithm involves remembering all values from the previous pixel. An even more efficient algorithm involves remembering column sums from the previous row (in addition to remembering all values from the previous pixel). Techniques that save previous information can greatly increase the algorithmic efficiency of this image analyzing process.
Uses of disparity from images[edit]
Knowledge of disparity can be used in further extraction of information from stereo images. One case that disparity is most useful is for depth/distance calculation. Disparity and distance from the cameras are inversely related. As the distance from the cameras increases, the disparity decreases. This allows for depth perception in stereo images. Using geometry and algebra, the points that appear in the 2D stereo images can be mapped as coordinates in 3D space.
This concept is particularly useful for navigation. For example, the Mars Exploration Rover uses a similar method for scanning the terrain for obstacles. The rover captures a pair of images with its stereoscopic navigation cameras and disparity calculations are performed in order to detect elevated objects (such as boulders). Additionally, location and speed data can be extracted from subsequent stereo images by measuring the displacement of objects relative to the rover. In some cases, this is the best source of this type of information as the encoder sensors in the wheels may be inaccurate due to tire slippage.
See also[edit]
Binocular summation
Binocular vision
Cyclodisparity
Epipolar geometry | biology | 1573788 | https://sv.wikipedia.org/wiki/Autostereogram | Autostereogram | Ett autostereogram är en singelbild av ett stereogram (SIS), som syftar till att skapa en illusion av en tredimensionell scen i hjärnan, från en tvådimensionell bild. För att uppfatta 3D-former i dessa autostereogram, måste hjärnan övervinna den normalt automatiska samordningen mellan fokusering och vergens.
Den enklaste typen av ett autostereogram består av ett horisontellt upprepat mönster och är känd som en tapetillusion. Sedda med ordentlig vergens verkar de upprepade mönstren flyta ovanpå eller under bakgrunden. I bokserien The Magic Eye har en annan typ av autostereogram kallats random dot autostereogram, vilket visas i exempelbilden till höger. I denna typ av autostereogram är varje pixel i bilden beräknad från en mönsterremsa och en djupkarta. Vanligtvis uppstår en dold 3D-scen när bilden betraktas med rätt vergens.
Autostereogram liknar vanliga stereogram, förutom att de ses utan stereobetraktning. Ett stereoskop visar 2D-bilder av samma objekt i något olika vinklar för vänster och höger öga, vilket gör att hjärnan för att rekonstruera det ursprungliga objektet måste kompensera för den binoculara skillnaden. Med ett autostereogram fås hjärnan att upprepa ett 2D-mönster från båda ögonen, för att sedan misslyckas med att matcha dem korrekt. De två intilliggande mönstren i bilden bygger på ett parallaxfel, vilket placerar ett virtuellt föremål på ett djup som skiljer sig från den övriga bilden.
Det finns två olika betraktningsprinciper för att se ett autostereogram, antingen med ett parallellt fokus (wall-eyed) eller med ett skelande (cross-eyed). De flesta autostereogram (alla i denna artikel) är utformade för att enbart ses på ett sätt, som vanligen bygger på ett parallellt fokus. Ett parallellt fokus bygger på att ögonen intar en relativt parallell vinkel, medan en skelande betraktning kräver att ögonen vinklas något.
Bakgrund
År 1838 publicerade den brittiska vetenskapsmannen Charles Wheatstone en studie av den binokulär synen som orsakar ett djupseende, till följd av skillnader i de horisontella positionerna för de två bilderna som ögonen registrerar. Hans studie stöddes av bilder med övergripande skillnader, som genom visning i spegelstereoskop kunde skapa virtuella djup. När de tvådimensionella bilderna kombinerades, skapades ett tredimensionellt djup.
Mellan 1849 och 1850 förbättrade den skotske vetenskapsmannen David Brewster Wheatstones stereoskop med linser i stället för speglar, vilket minskade enhetens storlek.
Brewster upptäckte "tapeteffekten". Han märkte att genom att stirra på upprepade mönster i tapeter kunde hjärnan luras att matcha mönster till att synbart befinna sig bakom väggen. Detta är grunden för wallpaper-stil "autostereograms", även kända som Single Image Stereograms (SIS).
År 1959 uppfann psykologen och vetenskapsmannen Béla Julesz det så kallade Random Dot Stereogram, medan han på Bell Labs kamouflerade objekt från flygbilder. Vid den tiden antogs ofta att djupseendet skapades i själva ögat, medan det nu är känt för att vara en komplicerad neurologisk process. Julesz använde datorteknik för att skapa ett stereopar av slumpmässig-dot bilder som när de betraktas under ett stereoskop, som orsakas av hjärnan för att se 3D-former. Detta påvisade att djupseendet är en neurologisk process.
Beskrivning
Tapetmönster
Stereoseende är den visuella blandning av två liknande, men inte identiska bilder, som resulterar i ett visuellt intryck av soliditet och djupseende. På grund av hjärnans komplexa mekanismer skapas ett tredimensionell intryck genom att försöka att matcha varje punkt (eller en uppsättning punkter) från ena ögats synfält med motsvarande punkt (eller en uppsättning punkter) i det andra ögats synfält. På grund av vergenskillnader, härleder hjärnan de punkter som fixpunkter i den annars osynliga z-axeln (djupet).
När hjärnan ska tolka ett upprepat bakgrundsmönster, blir det har det svårt att matcha de två ögonens synfält korrekt. Genom att titta på ett upprepande horisontellt mönster samtidigt som man mentalt försöker fokusera på en punkt bakom mönstret kan hjärnan fås att matcha den bild som ses med det ena ögat med en liknande bild som ses med det andra ögat. Med ett parallellt fokus skapas en illusion av ett plan med samma mönster, men bakom den riktiga väggen. Detta plans avstånd från den först sedda bilden är beroende på avståndet mellan de upprepade motiven.
Autostereogram använder upprepningarnas avstånd för att skapa tredimensionella bilder. Om något område av mönstret upprepas med ett mindre avstånd, kommer detta område att upplevas vara närmare än bakgrundsplanet. Om avståndet i upprepningarna istället är längre, kommer området kommer att framstå ligga längre bort (som ett hål i planet).
Detta autostereogram visar mönster på tre olika plan genom att upprepa motiven med olika avstånd. Någon som aldrig kunnat uppfatta 3D-former gömda i ett autostereogram, kan tycka att det är svårt att förstå uttalanden som: "3D-bilden hoppar bara ut från bakgrunden, när man stirrat på bilden tillräckligt länge". Det bidrar till att illustrera hur 3D-bilder "dyker upp" från bakgrunden från den andra betraktarens perspektiv. Om de virtuellt skapade 3D-objekt var verkliga, skulle en andra betraktare observerar scenen från sidan ser dessa objekt som svävar i luften ovanför bakgrundsbilden.
3D-effekterna i exemplet nedan skapas genom att upprepa motivet med tigerryttaren var 140:e pixel på bakgrundsplanet, motivet med hajryttaren var 130:e pixel och tigermotivet med 120 pixlars avstånd. Ju närmare en motivserie ligger horisontellt, ju högre de lyfts de från bakgrundsplanet. Detta upprepade avstånd motsvarar alltså djupvärdet i ett aktuellt autostereogram och det kallas också ibland för Z-buffer.
Hjärnan kan nästan omedelbart matcha hundratals mönster upprepade vid olika intervall för att återskapa ett antaget djup för varje mönster. En autostereogram kan innehålla ett 50-tal tigrar av varierande storlek, upprepade vid olika intervall mot en komplex, upprepad bakgrund. Trots den uppenbara kaotiska arrangemanget av mönster, kan hjärnan placera dem alla till rätt djup på basis av dess storlek och upprepningsfrekvens.
Djup
Autostereogram där mönster i en särskild rad upprepas horisontellt med samma avstånd kan avläsas antingen med en parallell eller skelande skelögd metod. I sådana autostereogram kommer båda typerna av betraktning skapa en liknande 3D-tolkning, med undantag för att en skelande betraktning inverterar djupet (bilder som annars framträder, fördjupas istället).
Motiven i en rad behöver inte vara placerade på samma avstånd. Ett autostereogram med varierande mellanrum mellan samma typ av motiv, kommer att återge dessa på olika djupplan. Djupet för varje symbol kalkyleras beroende på avståndet mellan denna och den föregående till vänster. Dessa typer av autostereograms är utformade för att läsas på ett enda sätt, antingen parallellt eller skelande. Alla autostereograms i denna artikel är kodade för parallell visning, om inte annat särskilt angivet. Autostereogram som är konstruerade för parallell betraktning kommer att producera osammanhängande 3D-mönster när de tolkas skelande.
De flesta Magic Eye-bilderna är avsedda för parallell betraktning.
Autosterogrammet till höger visar 3 plan längs x-axeln. Bakgrundens plan är på den vänstra sidan av bilden, det högsta planet ligger till höger och mellan dem finns ett smalt mittre plan i centrum av x-axeln. Med en början till vänster där ikonerna har ett avstånd på 140 pixlar, kan en specifik ikon "höjas" genom att flytta det ett visst antal pixel till vänster. Till exempel är mittplanet skapat genom att en ikon flyttats 10 pixlar åt vänster, som på sätt har skapat ett mellanrum på 130 pixlar. Hjärnan är inte beroende av begripliga motiv som representerar objekt eller begrepp. I detta autostereogram, mönster blir mindre och mindre ned på y-axeln, tills de ser ut som slumpmässiga punkter. Hjärnan kan dock fortfarande tolka det slumpmässiga punktmönstret.
Sambandet mellan avståndet mellan motiven och det upplevda djupet kan också beskrivas som i nästa bild. Det är en gråskala som representerar avståndet i pixlar till dess vänstra motsvarighet med ett gråskalevärde mellan svart och vitt. Ju närmare avståndet är, desto ljusare blir färgen.
Med hjälp av denna konvention kan en djupmappning skapas för ovanstående autostereogram där svart, grått och vitt representerar förändringar av 0, 10 och 20 pixlar. En djupmappning är även nyckeln till skapandet av random dot autostereograms.
Random-dot
Ett datorprogram kan ta en djupmappning och en medföljande mönsterbild för att producera en autostereogram. Programmet bygger mönstret horisontellt för att täcka ett område vars storlek är identiskt med djupmappningen. Vid varje pixel i den producerade bilden bestämmer programmet ett gråskalevärde för motsvarande pixel i djupmappningen och använder detta värde för att beräkna den nödvändiga horisontella pixelförskjutningen.
Ett sätt att åstadkomma detta är att låta programmet skanna av varje rad i bilden pixel för pixel, från vänster till höger. Det sätter den första serien av pixlar i en rad från mönsterbilden. Sedan används djupmappningen för att hämta lämpliga skiftvärden för efterföljande pixlar. För varje pixel, subtraheras övergången från bredden hos mönsterbilden för att komma fram till ett repetitionsintervall. Intervallet används sedan för att bestämma färgen på motsvarande pixel till vänster och sedan används dess färg till den nya pixeln.
Till skillnad från de enklare djupplan som kan skapas i en tapet kan mindre förändringar i intervall, som anges av djupmappningen, skapa en illusion med mjuka övergångar i fjärran. Detta är möjligt eftersom djupmappningens gråskala tillåter att enskilda pixlar placeras på ett av 2n djupplan, där n är antalet bitar som används av varje pixel i djupmappningen. I praktiken bestäms det totala antalet plan av antalet pixlar som används för bredden av mönsterbilden. Varje gråskalevärde måste översättas till pixelintervall för att kunna förskjuta pixlarna i det slutliga autostereogramet. Därför måste också antalet ingående plan vara mindre än mönsterbredden.
En detaljerad illusion kräver en mönsterbild som är mycket mer komplext än ett upprepat tapetmönster, varför ofta dessa mönster består av upprepade slumpmässiga punkter (random dots). När autostereogram betraktas rätt, framträder ett dolt 3D-motiv. Autostereograms av denna form kallas Random Dot Autostereograms.
Mjuka övergångar kan också uppnås med ett begripligt mönster, förutsatt att mönstret är komplext nog och inte har stora, horisontella enfärgade fläckar. Ett stort område med enhetliga färg utan förändring i nyans och ljusstyrka lämpar sig inte för pixelintervall, utifall ett intervall inte synbart kan förskjutas. Följande djupmappning av en haj med mjuk uttoning ger en perfekt avläsbart autostereogram och även om 2D-bilden innehåller små enfärgade områden kan hjärnan kan känna igen dessa små luckor och tolka dem som homogena. Upprepade mönster används ofta istället för slumpmässiga mönster och är även de kända som random dot autostereogram, vilket är förståeligt eftersom det skapas med hjälp av samma process.
Animationer
När en serie autostereogram visas efter varandra, på samma sätt som film visas, uppfattar hjärnan ett animerat autostereogram. Om alla autostereogram i animeringen är gjorda med hjälp av samma bakgrundsmönster, är det ofta möjligt att se svaga konturer av delar av det rörliga 3D-objektet i 2D-bilden utan parallellt fokus. De ständigt skiftande pixlarna i det rörliga objektet kan tydligt urskiljas från den statiska bakgrunden. För att eliminera denna bieffekt, används ofta även skiftande bakgrunder för att bättre dölja de rörliga delarna.
När ett regelbundet återkommande mönster visas på en CRT-skärm, som om det vore en tapetillusion, är det oftast möjligt att se djupförvrängningar. Dessa kan också ses i bakgrunden till ett statiskt random dot autostereogram. Dessa orsakas av de sidledes förskjutningar i bilden som på grund av små förändringar i linjeavsökning sedan tolkas som djup. Denna effekt är speciellt tydlig vid den vänstra kanten av skärmen, där skanningshastigheten minskar efter återgångsfasen. CRT-skärmar med högre kvalitet har bättre linjäritet och uppvisar mindre eller ingen bieffekt. Det gör inte heller TFT-skärmar som fungerar fungerar annorlunda och inte uppvisar denna effekt.
Visningsmekanismer
Det finns olika tekniker för att kunna se den avsedda tredimensionella bilden i en autostereogram. Medan vissa människor helt enkelt kan se 3D-bilden i ett autostereogram, måste andra träna sina ögon för att kunna undvika att fokusera oönskat.
Alla personer kan inte heller se 3D-illusionen i autostereograms. Eftersom ett autostereograms konstruktion är baserad på stereoseende kan personer med olika synskador, även de som bara drabbar ett öga, vara oförmögna att se dessa tre-dimensionella bilder.
Personer med amblyopi är oförmögna att se dessa tre-dimensionella bilder. Barn med en dålig eller dysfunktionell syn under en kritisk period i barndomen kan växa upp stereoblinda, eftersom deras hjärnor inte stimuleras att tolka stereobilder under den kritiska perioden. Om sådana synrubbningar inte behandlas i den tidiga barndomen blir skadan permanent och den vuxna kommer aldrig att kunna se autostereograms. Det uppskattas att omkring 1 till 5 procent av befolkningen är påverkad av amblyopi.
3D-perception
Ett utvecklat djupseende är resultatet från flera samverkande visuella funktioner. När det gäller föremål som befinner sig relativt nära ögonen, spelar binokulärseendet en viktig roll i djupuppfattningen. Binokulärseendet tillåter hjärnan att skapa en enda cyclopisk bild och för att sätta ett djup i dess olika delar.
Hjärnan använder en koordinatteknik (även känd som parallax) för att para ihop registrerade föremål för att kunna identifiera djupet av dessa. Djupet för varje punkt i den kombinerade bilden kan representeras av en gråskalepixel på en 2D-bild för att enklare förstå det. Ju närmare en punkt förefaller för hjärnan, desto ljusare nyans. Sättet som hjärnan uppfattar djup, med hjälp binokulärseendet, åskliggörs genom en cyklopisk bild på djupkartan som simulerar det faktiska koordinatsystemet.
Ögat har en del likheter med en vanlig kamera. Det har en justerbar iris som reglerar infallande ljus genom att förändra storleken på öppningen, likt en kameras bländare. Ögat måste inrikta ljuset för att kunna fokusera på en enda punkt på näthinnan för att skapa en skarp bild. Detta uppnås genom att ögonmuskler justera en lins bakom hornhinnan som sedan bryter ljuset på ett lämpligt sätt.
När en person ska fokusera på ett objekt, justeras de två ögongloberna i sidled för att rikta in sig på objektet, så att det ska visas i mitten av varje ögas näthinna. För att titta på en närliggande objekt, riktas ögongloberna mot varandra för att fokusera objektet. Detta kallas en skelande visning. När personen vill se ett avlägset objekt, dras ögongloberna isär för att bli nästan parallella med varandra. Detta är känt som parallellt fokus, där konvergensvinkeln är mycket mindre än den i en skelande vinkel.
Stereoseende baserad på parallax tillåter hjärnan att beräkna djupet av objekt i förhållande till en punktkonvergens. Det är konvergensvinkeln som ger hjärnan referensvärdet för djupet från vilket djupet av alla andra objekt kan härledas.
Simulerad 3D-perception
Vid normal betraktning av ett objekt fokuserar ögonen och konvergerar på samma avstånd i en process som kallas expansiv konvergens. När någon ska fokusera på ett avlägset objekt, plattar hjärnan automatiskt linserna och vrider ögongloberna för ett parallellt fokus. Det är möjligt att träna hjärnan att frikoppla dessa två automatiska förlopp, vilket krävs för att kunna se dessa dolda bilder.
Genom att fokusera på ett närliggande autostereogram, kan hjärnan så att säga tänka om för att kunna se alternativa upprepade mönster som visar de de dolda 3D-bilderna. Om mönstren som registreras av de båda synfälten är tillräckligt lika, kommer hjärnan att överväga att behandla dessa båda bilder som en del av en helhet. Denna typ av visualisering är känd som ett parallellt fokus (wall-eyed), eftersom ögongloberna måste inriktas som för att se ett avlägset föremål. Eftersom ögonen fokuserar på en punkt bakom bilden, är också den upplevda platsen för det virtuella föremålet bakom ett autostereogram. Det virtuella föremålet upplevs och vara större än dess ursprungsmönster på grund av en perspektivkortning.
Följande autostereogram visar 3 rader av upprepade mönster. Varje mönster upprepas på ett annat intervall för att placera den på ett annat djupplan. De två icke upprepande linjerna kan användas för att verifiera att ögonen inriktas korrekt i detta sammanhang. När detta autostereogram ska avläsas med hjälp av ett parallellt fokus som pekar förbi delfinmönstren i mitten, bör det uppstå två uppsättningar fladdrande linjer, som en följd av en binocular rivalitet.
Även om det först bara verkar vara 6 delfiner i bilden, bör hjärnan kunna se 7 delfiner i detta autostereogram. Detta är en bieffekt av parningen av ett liknande mönster av hjärnan. Det finns 5 par delfinmönster i denna bild, vilket tillåter hjärnan att skapa 5 uppenbara delfiner. Mönstret längst till vänster och höger har inte själva någon partner, men hjärnan försöker assimilera dessa två mönster på det etablerade djupetplanet, trots den binoculara rivaliteten. Som ett resultat finns det 7 uppenbara delfiner, men de båda längst ut får ett lätt flimmer, inte olikt de två fladdrande linjerna som uppstår när man tittar på den 4:e delfinen.
På grund av perspektivkortningen får konvergensskillnaden hjärnan att se upprepade mönster på olika plan, för att para ihop dem med storleken på de andra mönstren. I bilden med 3 rader med kuber, har alla medan alla kuber har samma fysiska 2D dimension, medan de på översta raden visas något större, eftersom de uppfattas som längre bort än kuberna på de nedre raderna.
Betraktningstekniker
Ögat har lättare att fokusera på ett objekt när det är finns mycket omgivande ljus. Med bra belysning, kan ögat dra ihop iris och ändå få tillräckligt med ljus för att nå näthinnan. Med andra ord sänks graden av frikoppling mellan fokusering och konvergens, för att kunna visualisera ett autostereogram, vilket också avlastar hjärnan. Därför kan det vara lättare när någon för första gången ska se sina första 3D-bilder att det sker i bra ljus.
Vergenskontroll är viktigt för att kunna se 3D-bilder. Det hjälper till för att kunna koncentrera sig på att bara hämta in de båda synfälten istället för att försöka fokusera direkt på att få en skarp begriplig bild. Trots att ögats lins också justeras automatiskt för att kunna skapa en skarp bild, är det möjligt att så att säga ta över kontrollen manuellt. Betraktaren växlar i stället mellan konvergerande och divergerande i processen för att se dubbla bilder, vilket annars är mest typiskt när hjärnan är utsatt för någon drog. Så småningom kommer hjärnan att lyckas skapa ett matchande mönsterpar och låsa fast denna grad av konvergens. Hjärnan kommer också att anpassa ögat linser, för att få en klar bild av detta matchande par. När detta är gjort kommer också bilderna runt de parade mönstren sammanfogas, om de ligger ungefär i samma konvergensgrad.
När någon flyttar sin uppmärksamhet från ett djupplan till ett annat (till exempel från översta raden i schackbrädet till nedersta raden), behöver ögonen anpassa sin konvergens för att matcha det nya återkommande intervallmönstret. Om denna förändringsgrad blir för hög, kan hjärnan ibland förlora den hårt intjänade frikopplingen mellan fokus och konvergens. För en förstagångs-betraktare kan det därför vara lättare att se autostereogram, om mönstren på en speciell rad förblir konstant.
I de autostereogram som är uppbyggda med slumpmässiga punkter (random dot) visas vanligen 3D-bilden i mitten av bakgrundens djupplan (se hajbilden i inledningen). Det kan bidra till att skapa rätt konvergens genom att först söka sikta (utan att fästa blicken) ovan eller under detta område, där mönstren vanligen upprepas med ett mer fast intervall. När väl hjärnan låser på bakgrundens djupplan, är redan konvergensgraden känd och det går lättare att matcha andra mönsterpar.
Majoriteten av autostereogram, likt de i denna artikel, är avsedda för ett parallellt fokus (wall-eyed). Ett sätt att hjälpa hjärnan koncentrera sig på avvikelserna, istället för att fokusera är att hålla bilden framför ansiktet och att nästan låta näsan röra bilden. Med bilden så nära ögonen, är det svårare att fokusera bilden. Hjärnan kan då ge upp försöken att låta ögonmusklerna hjälpa till för att få en tydligare bild. Om man långsamt flyttar bort bilden från ansiktet, samtidigt som man avstår från att fokusera eller att vrida ögonen, kommer hjärnan hitta ett läge där det går att låsa parande mönster.
Ett annat sätt är att söka låsa ett tänkt fokus på en punkt bakom bilden i ett försök att etablera rätt divergens, samtidigt som en del av uppmärksamheten fästes på bilden, för att övertala hjärnan att hitta alternativa mönster. En knep kan vara att betraktaren kan låsa på sin spegelbild, om det finns någon blank yta på bilden, som hjärnan då kan uppfatta som borde vara dubbelt så långt bort som själva bilden. Detta kan hjälpa till att övertyga hjärnan att det finns en fokusskillnad.
För skelande autostereogram behöver en annan metod vidtas. Betraktaren kan fokusera på ett finger som hålls mellan ögonen och bilden, samtidigt som det gradvis flyttas mot bilden, vilket kan ge en bättre möjlighet att inledningsvis se illusionen.
Terminologi
Stereogram
Användes ursprungligen för att beskriva ett par 2D-bilder som användes i stereoskop, som kunde skapa en #D-bild för betraktarna. Termen är nu ofta också använd tillsammans med autostereogram eller random dot autostereogram. Men Dr. Christopher Tyler, uppfinnare av autostereogram, använder konsekvent termen autostereogram för att referera till en singelbild, som skapar 3D-bilder.
Random dot stereogram (RDS)
"Slumpmässiga punkter" var ursprungligen ett par 2D-bilder, som vid visning i steroskop kunde skapa en 3D-bild. Denna term växlas nu ofta mot random dot autostereogram.
Single Image Stereogram (SIS)
Single Image Stereogram (SIS) är en synonym till autostereogram. SIS skiljer sig från de flesta stereogram genom sin användning av en enda 2D-bild istället för ett stereopar. När den inre 2D-bilden betraktas med rätt konvergens, får den hjärnan att omarbeta de olika mönstren till en virtuell 3D-bild, utan hjälp av någon optisk utrustning. SIS bilder skapas med hjälp av ett upprepat mönster.
Wallpaper autostereogram (tapetillusion)
Är en 2D-bild där mönster upprepas vid olika intervall, för att höja eller sänka ett uppfattat 3D läge i förhållande till ett virtuellt bakgrundsplan.
Random-dot autostereogram
Är också känt som Single Image Random Dot Stereogram (SIRDS). Termen refererar också till autostereograms, där dolda 3D-bilder skaps genom ett slumpmässigt mönster av bildpunkter.
Single Image Random Text Stereogram (SIRTS)
En enda bild med slumpvis placerad text, är ett alternativ till SIRDS, som normalt använder ASCII-text istället för punkter för att skapa 3D-former av ASCII-konst.
Referenser
Noter
Källor
N. E. Thing Enterprises (1993). Magic Eye: A New Way of Looking at the World. Kansas City: Andrews and McMeel.
Christopher Tyler and Clarke, M.B. (1990) "The Autostereogram". Stereoscopic Displays and Applications, Proc. SPIE Vol. 1258:182–196.
Marr, D. and Poggio, T. (1976). "Cooperative computation of stereo disparity". Science, 194:283–287; October 15.
Bela Julesz (1964). "Binocular depth perception without familiarity cues". Science, 145:356–363.
Bela Julesz (1963). "Stereopsis and binocular 3d Stereogram rivalry of contours". Journal of the Optical Society of America, 53:994–999.
Bela Julesz and J.E. Miller. (1962). "Automatic stereoscopic presentation of functions of two variables". Bell System Technical Journal, 41:663–676; March.
Scott B. Steinman, Barbara A. Steinman and Ralph Philip Garzia. (2000). Foundations of Binocular Vision: A Clinical perspective. McGraw-Hill Medical.
Externa länkar
TIM - Online raytracer, som också genererar anaglyphs (för röd/blå glasögon) och autostereogram
Online ASCII stereogramsgenerator
Stereogram-exempel
Optiska illusioner
Perception | swedish | 0.515315 |
3D_vision/vision-and-visual-perception-challenges.txt | * Reviews / Why join our community?
* For companies
* Frequently asked questions
* Contact
* UX Courses
* Master Classes
* Community
* Literature
* Blog
* Search
* Log in
* Join our community Join us
Please upgrade your browser as it’s outdated. You’ll reduce security risks
and help make the internet better.
Your browser is outdated— upgrade it now .
Open menu Close menu
Search
Join us
* UX Courses
* Master Classes
* Community
* Literature
* Blog
* Search
Log in
* Reviews / Why join our community?
* For companies
* Frequently asked questions
* Contact
# Vision and Visual Perception Challenges
10 months ago | 12 min read
689 shares
Share this article Cite this article
Cite this article
It sounds so simple; take some light and turn it into an understanding of the
world around you – we all do it every day; yet, there isn’t a single computer
on earth, no matter how powerful, that can mimic the feat of vision to any
real extent.
Vision requires us to separate the foreground from the background, recognize
objects viewed from an incredible range of spatial orientations, and
accurately interpret spatial cues (or risk walking into doors rather than
through them).
## Visual Perception – The Eye
Vision begins in the eye, which receives the inputs, in the form of light, and
finishes in the brain which interprets those inputs and gives us the
information we need from the data we receive. The components of the eye are
pictured below.
© National Eye Institute, Fair Use.
The eye focuses light on the retina. In the retina, there is a layer of
photoreceptor (light receiving) cells that are designed to change light into a
series of electrochemical signals to be transmitted to the brain. There are
two types of photoreceptors – rods and cones.
Rods tend to be found in the peripheral areas of the retina and are designed
to respond to low levels of light. They are responsible for our night vision
and because of where they are placed on the retina – you can improve your
night vision by learning to focus slightly to the side of whatever you are
looking at, allowing the light to reach the rod cells most successfully.
Cones cells are found in the fovea (the center of the retina); cone cells
handle the high acuity visual tasks such as reading and color vision. Cone
cells respond to red, green or blue light and by combining the signals from
these three receptors, we can perceive a full range of color.
Once the light has been processed by the photoreceptors, an electrochemical
signal is then passed via a network of neurons to the ganglion cells further
back in the retina. The neurons are designed to help detect the contrasts
within an image (such as shadows or edges) and the ganglion cells record this
(and other information) and pass an amended electrochemical signal, via the
optic nerve, to the brain.
Marcus Tullius Cicero, the Roman orator, said, “The face is a picture of the
mind with the eyes as its interpreter.” In fact, the eyes are simply the first
step in interpreting the mind – the brain is the essential second part of the
process.
## Visual Perception – The Brain
Visual perception takes place in the cerebral cortex and the electrochemical
signal travels through the optic nerve and via the thalamus (another area of
the brain) to the cerebral cortex. In addition to the main signal sent to the
cerebral cortex – the optic nerve passes additional data to two other areas of
the brain.
The first is the pretectum which controls the pupils and enables the
adjustment of pupil size based on the intensity of light that we see. It’s why
your pupils contract in bright sunlight and expand in the dark.
The second is the superior colliculus. This part of the brain controls the
motion of the eye, which is actually not smooth but rather a series of short
jumps. These jumps are called saccades. The reason that the eye jumps rather
than moves in a smooth action is that a smooth action would create motion blur
(in the same way that a long exposure photography shot can be used to create
motion blur) – the jumps allow for a “reset” of the information condition and
eliminate that blur.
In the thalamus, the projections from the retina are processed in the lateral
geniculate nucleus. This separates the outputs from the retina into two
streams. The first stream handles color and fine structure within the output
and the other handles the contrast and motion perceived.
The first stream is then sent to the visual cortex, which is pictured below,
to an area known as the primary visual cortex or V1. V1 has a bunch of cells
whose job is to calculate where objects are in space relative to us. The
signal received is mapped on a 2-D map to determine the overall placement of
objects and then the third dimension is added when the map from each eye is
compared with the other. In short, they calculate the depth by triangulating
every point within the image.
© Selket. CC BY-SA 3.0
In 1981, David Hubel and Torsten Wiesel, won the Nobel Prize for demonstrating
that a column of orientation cells within V1 enables the brain to determine
the edges of objects by focusing on the spatial orientation of objects within
the image received by the brain.
There are other areas of the central cortex that help further process the
image; V2, V3 and V4. V2 helps us control our color perception by helping us
separate the color of an object from the color of ambient light –
interestingly, the color we perceive an object to be when this process is
complete is usually the color we expect to perceive the object in. This
suggests that the V2 area is not just handling color processing but also
comparing the color of the processed image with our memories of previous
examples of an object of that type .
V3 and V4 handle face and object recognition and normally do a very good job
of this – though they can be “pranked” with optical illusions .
All the data from all these areas of the brain are then combined over and over
again throughout the day to help us make sense of what we see.
## Visual Perception – The System Demands
It isn’t clearly understood just how much data the visual perceptive system in
human beings processes. We do know that the storage capacity of the human
brain is enormous; though the network of neurons is only a trillion or so
neurons, each neuron is capable of combining with other neurons to store much
more information in parallel than they could in series.
There are almost certainly chemical “tricks” that the brain pulls to reduce
the amount of data compared to, say, the data processed by a camera operating
at the same speed (as the eye and the brain), but what those tricks are – we
are yet to understand fully.
It is estimated that 70% of all the data we process is visual, but again this
is not a “hard fact” but based on our understanding of how data works in
computer systems.
## Challenges Associated with Visual Perception
While long-sightedness and short-sightedness can both be considered challenges
associated with visual perception, they are typically easily corrected with
glasses and are not a major concern for designers in any field. The two most
common challenges that designers may face are visual stress and color
blindness .
### Visual Stress
Visual stress is a peculiar phenomenon affecting a small but significant
percentage of the population. When striped patterns (at about three cycles per
degree) are shown at a flicker rate of about 20 Hz (cycles per second), they
can cause seizures in people susceptible to visual stress.
Back in 1997, a Japanese TV network pulled the plug on a TV show which caused
visual stress in over 700 children. It caused seizures and, in extreme cases –
vomiting of blood.
Visual stress is sometimes known as “pattern-induced epilepsy,” and while this
is the most extreme manifestation of visual stress, it’s worth noting that
visual stress can be induced at milder levels by striped patterns in most
people.
Even normal text (which is arranged in horizontal stripes) can cause problems
for some people, and certain fonts may exacerbate the problem. Visual stress,
in this instance, can distort print and cause rapid fatigue when reading. In
some respects, the effect of visual stress is very similar to the ways
dyslexics see print, as pictured below.
© Willard5. Fair Use.
### Color Blindness
Color blindness is mislabeled. It’s not blindness but rather a deficiency in
color vision. It is the inability (or sometimes decreased ability) to see
certain colors or perceives color contrasts in normal light.
For some reason, men suffer from color blindness more often than women. 1 in
12 men have color blindness compared to 1 in 200 women. Color blindness is
normally genetic and the trait is inherited from the mother but in some cases,
it may be induced by disease or aging.
The most common form of color blindness is red/green color blindness – this
doesn’t mean that the person cannot see red or green but rather that they
confuse colors that have some elements of red or green within them. There are
other less common forms of color blindness that affect different pairings of
colors too. There are many tests for color blindness (some are pictured
below), but the condition should not be self-diagnosed but rather diagnosed by
an optician or medical professional.
© Eddau. CC BY-SA 3.0
## Awareness
Designers should be aware of visual stress and color blindness and ideally
test their designs with people known to suffer from these conditions to ensure
that the effects are muted or eliminated entirely.
## The Take Away:
Human vision is complex and more powerful than any of today’s computers. The
process by which the signal (in the form of light) is passed through the
retina of the eye and then processed in the brain is complex and still not
completely understood.
Designers need to be aware that there are common processing errors and, in
particular, to be aware of visual stress and color blindness so that they can
adjust their designs to minimize the impacts of these errors.
## References and Resources:
Course: The Ultimate Guide to Visual Perception and Design
Read about the capacity of the human brain.
You can find a detailed account of the components of the visual cortex here
.
Learn all about sensory processing in the brain.
Find out more about color blindness here .
Hero image: © Jjw. Edits by: Ana Zdravic, CC BY-SA 3.0
### Perception and Memory in HCI and UX
Perception and Memory in HCI and UX
Closes in
17
days
booked
View Course
## Get Weekly Design Insights
Join 311,145 designers who get useful UI / UX Design tips from our
newsletter.
A valid email address is required.
Go
## Topics in This Article
Visual Perception Color Blindness Information Visualization Visual Design
Graphic Design Perception
689 shares
Share this article Cite this article
## What You Should Read Next
### 10 Great Sites for UI Design Patterns
10 Great Sites for UI Design Patterns
You don’t want to spend your whole life redesigning the wheel, do you? No,
neither do we. If you are looking for a desig
* 1.4k shares
* 3 mths ago
Read article
### How to Change Your Career from Graphic Design to UX Design
How to Change Your Career from Graphic Design to UX Design
If there’s an occupation that is 100% linked with the public’s idea of what
design is all about, it’s graphic design. Fr
* 1.4k shares
* 3 mths ago
Read article
### Repetition, Pattern, and Rhythm
Repetition, Pattern, and Rhythm
Let’s look at three subjects that, at first glance, may strike you as being
incredibly basic and self-explanatory. Howev
* 1.2k shares
* 3 mths ago
Read article
### The Grid System: Building a Solid Design Layout
The Grid System: Building a Solid Design Layout
Now that we’ve seen some grids at work in the Rule of Thirds article, let’s
examine them a little more deeply. As a conc
* 1.2k shares
* 3 years ago
Read article
### Information Overload, Why it Matters and How to Combat It
Information Overload, Why it Matters and How to Combat It
Designers often need to convey information to the users of their designs.
Specialists in information visualization desig
* 1.1k shares
* 3 years ago
Read article
### The Key Elements & Principles of Visual Design
The Key Elements & Principles of Visual Design
Visual design is about creating and making the general aesthetics of a product
consistent. To create the aesthetic style
* 1.1k shares
* 1 year ago
Read article
### Recalling Color Theory Keywords: a way to refresh your memories!
Recalling Color Theory Keywords: a way to refresh your memories!
Choosing the best combination of colors for an interactive design layout is
not, as it may appear, a guessing game. Know
* 1.1k shares
* 3 years ago
Read article
### The Ultimate Guide to Understanding UX Roles and Which One You Should Go
For
The Ultimate Guide to Understanding UX Roles and Which One You Should Go For
UX design roles are confusing. You might know what a “UX designer” does, but
what about a “visual designer”, “product de
* 1k shares
* 6 mths ago
Read article
### Flow Design Processes - Focusing on the Users' Needs
Flow Design Processes - Focusing on the Users' Needs
It can be really tempting to start a design project by leaping into the deep
end and starting to sketch out pages and wo
* 1k shares
* 3 years ago
Read article
### The Golden Ratio - Principles of form and layout
The Golden Ratio - Principles of form and layout
Now, we’re going to look at a subject that comes directly from mathematics and
that we can also find all around us – the
* 997 shares
* 3 years ago
Read article
## Top Articles
* The 5 Stages in the Design Thinking Process 1.8k shares
* What is Design Thinking and Why Is It So Popular? 1.6k shares
* Personas – A Simple Introduction 1.5k shares
* Bad Design vs. Good Design: 5 Examples We can Learn From 1.5k shares
* 10 Great Sites for UI Design Patterns 1.4k shares
## Top Topics
Design Thinking (DT) 49 articles 10 videos
User Experience (UX) Design 150 articles 8 videos
Graphic Design 19 articles 4 videos
Color Theory 6 articles 6 videos
User Interface (UI) Design 60 articles 9 videos
## Open Access—Link to us!
We believe in Open Access and the democratization of knowledge .
Unfortunately, world-class educational materials such as this page are
normally hidden behind paywalls or in expensive textbooks.
If you want this to change , cite this article , link to us, or join us
to help us democratize design knowledge !
## Search
Close
### Popular related searches
### Filters
### Search Results
## Footer navigation
With 172,807 graduates, the Interaction Design Foundation is the biggest
online design school globally. We were founded in 2002.
### Connect With Us
Reach us at [email protected] or through our online contact form
.
LinkedIn page Instagram page YouTube page X page Facebook page
Have questions? Check our frequently asked questions .
### Get Inspired Weekly
Join 311,145 designers and get weekly inspiration and design tips in your
inbox.
Email
Subscribe
Please write a valid email address.
### Browse UX / UI Design Topics
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
#
### UX Courses
* Beginner UX Courses
* Intermediate UX Courses
* Advanced UX Courses
### Community
* Master Classes
* Local Groups
* Discussions
### Literature
* UX Daily Articles
* UX Topics
* UX Books
### About
* About Us
* The People Behind
* Contact Us
* Terms of Use / Privacy
* For companies
* What is UX Design?
* Give as gift
* Careers
Open
##### Privacy Settings
Close
By using this site, you accept our Cookie Policy and Terms of Use .
Customize
Our digital services use necessary tracking technologies, including third-
party cookies, for security, functionality, and to uphold user rights.
Optional cookies offer enhanced features, and analytics.
Essential
Experience the full potential of our site that remembers your preferences and
supports secure sign-in.
###### Security
Governs the storage of data necessary for maintaining website security, user
authentication, and fraud prevention mechanisms.
###### Enhanced Functionality
Saves your settings and preferences, like your location, for a more
personalized experience.
###### Referral Program
We use cookies to enable our referral program, giving you and your friends
discounts.
###### Error Reporting
We share user ID with Bugsnag and NewRelic to help us track errors and fix
issues.
Analytics
Optimize your experience by allowing us to monitor site usage. You’ll enjoy a
smoother, more personalized journey without compromising your privacy.
###### Analytics Storage
Collects anonymous data on how you navigate and interact, helping us make
informed improvements.
###### Google
Differentiates real visitors from automated bots, ensuring accurate usage data
and improving your website experience.
Personalization
Lets us tailor your digital ads to match your interests, making them more
relevant and useful to you.
###### Advertising Storage
Stores information for better-targeted advertising, enhancing your online ad
experience.
###### Personalization Storage
Permits storing data to personalize content and ads across Google services
based on user behavior, enhancing overall user experience.
###### Advertising Personalization
Allows for content and ad personalization across Google services based on user
behavior. This consent enhances user experiences.
###### User Data
Enables personalizing ads based on user data and interactions, allowing for
more relevant advertising experiences across Google services.
Advertising
Receive more relevant advertisements by sharing your interests and behavior
with our trusted advertising partners.
###### Meta Pixel
Enables better ad targeting and measurement on Meta platforms, making ads you
see more relevant.
###### Meta CAPI
Allows for improved ad effectiveness and measurement through Meta’s
Conversions API, ensuring privacy-compliant data sharing.
###### LinkedIn Insights
Tracks conversions, retargeting, and web analytics for LinkedIn ad campaigns,
enhancing ad relevance and performance.
###### LinkedIn CAPI
Enhances LinkedIn advertising through server-side event tracking, offering
more accurate measurement and personalization.
###### Google Ads Tag
Tracks ad performance and user engagement, helping deliver ads that are most
useful to you.
Accept all
Save Settings
## Share Knowledge, Get Respect!
Share on:
or copy link
Copy link
## Cite according to academic standards
Simply copy and paste the text below into your bibliographic reference list,
onto your blog, or anywhere else. You can also just hyperlink to this article.
Citation format APA (recommended) MLA IEEE ACM What is this?
Copy citation
Interaction Design Foundation - IxDF. (2023, June 29). Vision and Visual
Perception Challenges . Interaction Design Foundation - IxDF.
Interaction Design Foundation - IxDF. “Vision and Visual Perception
Challenges” Interaction Design Foundation - IxDF. 30 Apr. 2024
Interaction Design Foundation - IxDF. “Vision and Visual Perception
Challenges” Interaction Design Foundation - IxDF. (accessed Apr. 30, 2024).
Interaction Design Foundation - IxDF. 2023\. Vision and Visual Perception
Challenges Retrieved April 30, 2024 from
Cite selection
Copied to clipboard!
## New to UX Design? We’re giving you a free ebook!
Download our free ebook The Basics of User Experience Design to learn about
core concepts of UX design.
In 9 chapters, we’ll cover: conducting user interviews, design thinking,
interaction design, mobile UX design, usability, UX research, and many more!
Download free ebook Go
A valid email address is required.
Get free UX design learning material every week
311,145 designers enjoy our newsletter—sure you don’t want to receive it?
## New to UX Design? We’re Giving You a Free ebook!
Download our free ebook The Basics of User Experience Design to learn about
core concepts of UX design.
In 9 chapters, we’ll cover: conducting user interviews, design thinking,
interaction design, mobile UX design, usability, UX research, and many more!
Download free ebook Go
A valid email address is required.
Get free UX design learning material every week
311,145 designers enjoy our newsletter—sure you don’t want to receive it?
| biology | 285923 | https://da.wikipedia.org/wiki/X3D | X3D | X3D er et royalty frit åbent ISO-standard XML-baseret filformat, for 3D grafik.
Indeledning
Formatet er en viderudvikling af Virtual Reality Modeling Language (VRML) og byder på
udvidelser til VRML, såsom Humanoid Animation, NURBS og GeoVRML, mulighed for både, at bruge
XML-syntaks og VRML-syntaks og understøttelse af udvidede Application Programmer Interfaces (API).
En fordel ved formatet er, at man ved hjælp af et plug-in til en webbrowser, kan interagere med 3D-modeller
over internettet.
Brugsmuligheder
Formatet kan bruges i mange forskellige sammenhænge:
CAD og arkitektur
træning og uddannelse
underholdning
Understøttelse
X3D understøtter:
3D grafik
Polygonal geometri
Parametrisk geometri
Hierakisk transformation
Belysning
Overflader
Texture mapping
Pixel eller vertex shaders
2D grafik
Rumlig tekst
2D vektor grafik
2D/3D kompostioner
CAD data: Oversættelse af CAD data til et åbent format, i forbindelse med interaktivitet
Animation: Timere og interpolatorer giver mulighed for:
Kontinuerlig animation
Humanoid animation
Morphing
Rumlig lyd og billede
Audio-visuelle kilder mappes til geometrien i scener.
Bruger interaktion
Navigation
Kameraer
Bruger bevægelse
Kollisions detektion
Nærheds detektion
Synsvidde detektion
Netværk, det er muligt at bygge scener med elementer, der er lokaliseret andre steder på et netværk.
Fysisk simulation og real-tids kommunikation.
Se også
Flux (program)
Referencer
Eksterne henvisninger
Officiel hjemmeside
X3D specifikationer
Programmeringssprog | danish | 0.794762 |
3D_vision/science-vision-perception-really-reality.txt | # Columbia University in the City of New York
Asset 1
Mind. Brain. Behavior.
menu close
* Science
* People
* Programs
* Engage
* Events
* News
* About
Support
* * * *
Search Search
close
### Discover new insights when you open your inbox
Subscribe
Mar 14, 2018 6:30 pm
#### Tell a Friend:
Brain Awareness Week
# The Science of Vision: Is Perception Really Reality?
## Featuring Tiago Siebert Altavini, PhD
## March 14th, 6:30 pm – 8:00 pm at the Education Lab, Jerome L. Greene
Science Center
Register Here
### Contact
[email protected]
### Add To Calendar
* iCal / Outlook
* Google
* Yahoo
We rely heavily on visual perception to guide ourselves around the world. Our
brain is very good at processing visual information about different shapes,
colors and brightness variations. However, the meaning of an object is not an
intrinsic physical feature of the object, but is also defined by internal
representations in our brain, often based on past experience. Thus visual
perception is not just the processing of information about the physical
attributes of what we see, but the combination of these with the internal
representations the brain already has. How is it that our memory and
expectations influence our visual perception? That’s what we are trying to
find out.
Dr. Tiago Siebert Altavini is a neuroscientist working in the Laboratory of
Neurobiology at The Rockefeller University. He was an undergrad at the
University of Brasilia and obtained his PhD from the University of Rio Grande
do Norte, where he worked with Dr. Kerstin Schmidt at the University’s Brain
Institute. His PhD research focused on the visual connections in the brain and
their influence in patterns of spontaneous brain activity. He currently works
with Dr. Charles Gilbert, to investigate the top-down influence of feedback
connections on object recognition. The aim of such research is to understand
the mechanisms by which expectation influences visual perception.
The event is free but registration is encouraged.
This lecture is a Know Science Public Talk. Know Science, Inc. is a not-for-
profit science outreach organization that provides the public with free
lectures and outreach events. Learn more at: http://knowscience.org/
Venue: the Education Lab, Jerome L. Greene Science Center
609 W 129th St., New York, NY 10027
## Connect with us
## Discover new insights when you open your inbox.
### Get thought provoking updates on neuroscience, as well as news about
upcoming events and activities at the Institute.
Subscribe
### Follow us for updates
footer-logo
* * * *
## The Future in Mind
* Science
* People
* Programs
* Engage
* Events
* News
* About
* Press Room
* Contact Us
* Work with Us
* Internal Website
Support
©2019 The Zuckerman Institute, Columbia University
Interneurons illuminated in different colors in a mouse spine (Columbia's
Zuckerman Institute)
| biology | 274948 | https://da.wikipedia.org/wiki/Virksomhedsteori | Virksomhedsteori | Virksomhedsteori (engelsk: Activity theory) er en teori inden for psykologi og kognitionsforskning, der betoner tænkningens og bevidsthedens sociale, historiske og kulturelle natur. Den har fundet anvendelse på forskellige områder, herunder pædagogik og i informationsvidenskab.
Inden for Biblioteks- og informationsvidenskab er den især anvendt til menneske-maskingrænseflader. Nyere anvendelser omfatter desuden studiet af brugere og en generel forståelse af information og informationsformidling.
Links
Leont'ev, A. Activity, Consciousness, and Personality
Engeström, Y. Learning by expanding
Litteratur
Bannon, L. (1997). Activity Theory, http://www.irit.fr/ACTIVITES/GRIC/cotcos/pjs/TheoreticalApproaches/Actvity/ActivitypaperBannon.htm .
Boedker, S. (1990). Activity theory as a challenge to systems design. Aarhus, Aarhus University.
Engeström, Y. (1987). Learning by expanding. Helsinki, Orienta Consultit.
Engeström, Y. (1990). Learning, working and imagining : twelve studies in activity theory. Helsinki, Orienta-konsultit.
Engeström, Y. (1993). Developmental studies of work as a testbench of activity theory. Understanding Practice: Perspectives on Activity and Context. S. Chaiklin and J. Lave. Cambridge: 4-103
Engeström, Y., J. Lompscher, et al. (2005). Putting activity theory to work : contributions from developmental work research. International cultural-historical human sciences ; Bd. 13. Berlin, Lehmanns Media: 644 s.
Engeström, Y., R. Miettinen, et al. (1999). Perspectives on activity theory. Cambridge, Cambridge University Press.
Kaptelinin, V. (1992). Activity Theory: Implications for Human-Computer Interaction.
Kaptelinin, V., B. Nardi, et al. (1999). The Activity Checklist: A Tool For Representing the "Space" of Context. Interactions. July/August 1999: 27-39.
Korpela, M. and A. Mursu (2003). Means for cooperative work and activity networks: An analytical framework. ECSCW'03, 8th European Conference of Computer-Supported Cooperative Work, Helsinki, Finland.
Kuuti, K. (1991). Activity Theory and its application to information system research. Amsterdam.
Kuuti, K. (1996). Activity Theory as a Potential Framework for Human-Computer Interaction Research. Context and Consciousness. B. A. Nardi. Cambridge, MA: 17-44.
Leontiev, A. N. (1978). Activity, Consciousness and Personality. New York, Prentice Hall, Englewood Cliffs.
Leontiev, A. N. (1981). Problems of the Development of the Mind. Moscow, Progress. English translation, Moscow: Progress Press. (Russian original 1947).
Nardi, B. A. (1996). Context and Consciousness: Activity Theory and Human-Computer Interaction. Cambridge (MA), The MIT Press.
Vygotsky, L. S. (1962). Thought and Language. New York, John Wiley & Sons.
Vygotsky, L. S. (1978). Mind in society: The development of higher psychological processes. Cambridge, MA, Harvard Business Press.
Vygotsky, L. S. (1981). The genesis of higher mental functions. The concept of activity in Soviet psychology. J. V. Wertsch. Armonk, Sharpe.
Wertsch, J. V. (1981). The concept of activity in soviet psychology. New York.
Web Links
What is Activity Theory?
Activity theory (Cultural Historical Activity Theory, CHAT
Center for Activity Theory and Developmental Work Research
Lexikon. Wissenswertes zur Erwachsenenbildung
Acting with Technology: Activity Theory and Interaction Design
Virksomhedsteorikonferencerne i Danmark
Se også
Kritisk psykologi
Lev Vygotskij
Psykologi
Biblioteks- og informationsvidenskab | danish | 0.847388 |
3D_vision/visual-perception.txt | Skip to main content
Switch Language
* English
* 繁體中文
* * * *
* +852 2849 6138
DONATE 捐助支持
## Main navigation
* We Do
* Our Services
* Enquiry & Admissions
* Assessments & Consultation
* Individual Therapies
* Group Programmes
* Parenting
* Get Tips
* Developmental Milestones
* Parent Tips
* SEN School Tips
* Health & Additional Needs
* Navigating Additional Needs in Hong Kong
* Our Video Series
* For CDC Parents
* Calendar
* Weather Procedures
* Forms & Info
* Financial Assistance
* News
* Newsletter
* Monthly Classroom News
* Sen Network
* SEN Events
* Submit an Event
* Get Involved
* Our Impact
* Be Our Partner
* Donate
* Donate Offline [ Form ]
* My Charity Event [ Form ]
* Daddy Daughter Ball
* Volunteer
* We are
* Our Approach
* Our Story
* Our Team
* Executive Committee
* Annual Reports
* Careers
* Why Work With Us
* Service Quality Standards
×
Search
Search
## Main navigation
* We Do
* Our Services
* Enquiry & Admissions
* Assessments & Consultation
* Individual Therapies
* Group Programmes
* Parenting
* Get Tips
* Developmental Milestones
* Parent Tips
* SEN School Tips
* Health & Additional Needs
* Navigating Additional Needs in Hong Kong
* Our Video Series
* For CDC Parents
* Calendar
* Weather Procedures
* Forms & Info
* Financial Assistance
* News
* Newsletter
* Monthly Classroom News
* Sen Network
* SEN Events
* Submit an Event
* Get Involved
* Our Impact
* Be Our Partner
* Donate
* Donate Offline [ Form ]
* My Charity Event [ Form ]
* Daddy Daughter Ball
* Volunteer
* We are
* Our Approach
* Our Story
* Our Team
* Executive Committee
* Annual Reports
* Careers
* Why Work With Us
* Service Quality Standards
Search
## Visual Perception
* 29 September 2017
* Posted By: devadmin
* Category: Parent Tips
What is Visual Perception? Visual perception refers to the brain’s ability to
make sense of what the eyes see. Some children have 20/20 vision but they can
still have problems with visual perception processing. It has nothing to do
with their vision. Why is it important? Good visual perceptual skills are
important for many every day skills such as reading, writing, completing
puzzles, cutting, drawing, completing math problems, dressing, finding your
sock on the bedroom floor as well as many other skills. Without the ability to
complete these everyday tasks, a child’s self-esteem can suffer and their
academic and play skills can also be compromised. If a child has difficulties
with visual perception they may have problems with the following activities:
* Completing puzzles or dot-to-dot pictures.
* Spatial concepts such as “in, out, on, under, next to, up, down and in front ”
* Differentiating between “b, d, p, q”.
* Reversing numbers or letters when writing.
* Losing their place on a page when reading or writing.
* Remembering left and right.
* Remembering the alphabet in sequence.
* Coping from one place to another (e.g. from board, from a book, from one side of the paper to the other).
* Dressing (i.e. matching shoes or socks).
* Discriminating between the size of letters and objects.
* Filtering out visual distractions such as colourful bulletin boards or movement in the room in order to attend to the task at hand.
* Sorting and organising personal belongings (i.e. may appear disorganised or careless in work).
* Hidden picture activities or finding a specific item on a cluttered desk.
Here are some activities to help children with visual perception difficulties:
* Hidden pictures games in books such as “Where’s Wally” and “I spy”.
* Picture drawing: Practice completing partially-drawn pictures.
* Dot-to-dot
* Memory games: Playing games such as Memory .
* Sensory activities: Use bendable things such as pipe cleaners to form letters and shapes (because feeling a shape can help them visualise the shape). The letters can then be glued onto index cards, and later the child can touch them to “feel” the shape of the letter.
* Construction-type activities such as Duplo, Lego or other building blocks.
* Flash cards with a correct letter on one side and an incorrectly formed letter on the other side. Have your child try to draw the letter correctly, then turn over the card to see if it is right. (Have them write in sand or with finger paint to make it more fun).
* Word search puzzles that require your child to look for a series of letters.
* Copy 3-D block designs using building blocks, Lego or Duplo.
* Identify objects by touch: Place plastic letters into a bag, and have your child identify the letter by “feeling it”.
* Bingo: which requires your child to look for a specific number.
If you feel your child is having difficulties with their visual perception
processing, you can contact an Occupational Therapist for an in-depth
assessment.
#### NEWSLETTER SIGNUP
Email Address
### Recent posts
Exploring books together!
Parent Tips
Stuttering and Typical Disfluency – What’s the Difference?
Parent Tips
Why is Attention So Crucial for Your Child's Development?
Parent Tips
## QUICKLINKS
* Donate
* Careers
* Centre Calendar
* Weather Procedures
* Contact Us
#### Opening Hours
Fortress Hill Centre
Monday | 08:30 - 18:00
---|---
Tuesday | 08:30 - 18:00
Wednesday | 08:30 - 18:00
Thursday | 08:30 - 18:00
Friday | 08:30 - 18:00
Saturday | 08:30 - 17:30
Sunday | CLOSED
North Point Centre
Monday | ENQUIRIES ONLY
---|---
Tuesday | 08:30 - 18:00
Wednesday | 08:30 - 18:00
Thursday | 08:30 - 18:00
Friday | 08:30 - 18:00
Saturday | 08:30 - 17:30
Sunday | CLOSED
#### CONTACT US
* Unit 7, 4/F, Victoria Centre, 15 Watson Road, Fortress Hill, Hong Kong
* +852 2849 6138
* +852 2849 6900
* [email protected]
* 3/F, North Point Welfare Facilities Block, 123 Java Road (Harbour North Phase 2), North Point, Hong Kong
* +852 2849 2018
* +852 2849 2280
* [email protected]
Copyright © The Child Development Centre. We are a Hong Kong Registered
Charity IRD No. 91/1579 and a company limited by guarantee.
Terms and Conditions | Privacy Policy
* * * *
| biology | 248053 | https://da.wikipedia.org/wiki/Regent%20Street | Regent Street | Regent Street er en central handelsgade og gennemfartsvej i det centrale London. Den har navn efter prinsregenten, den senere George 4., og var en del af byplanen fra 1811 tegnet af John Nash. Gaden tilhører formelt kronen, men vedligeholdes af Londons myndigheder.
Den starter som Lower Regent Street i krydset med Charles II Street og Waterloo Place, går nordover til Piccadilly Circus. Selve Regent Street begynder fra Piccadilly Circus og går i en kvart cirkelbue til Oxford Circus. På oversiden af Oxford Circus begynder Upper Regent Street, som slutter ved krydset med Langham Place, Cavendish Place og Mortimer Street.
Gaden er kendt for en række store forretningskæders flagskibsbutikker som Hamleys legetøjsbutik, som indtil 1990'erne var verdens største, med seks etager. Tæt ved ligger Liberty's, et af de ældste varehuse i byen, Austin Reed, Apple Store, Jaeger og Superdry.
Aquascutums første butik lå ligeledes på Regent street.
London Underground har en station i hver ende af Regent Street: Oxford Circus (Bakerloo line, Central line og Victoria line) og Piccadilly Circus (Piccadilly line og Bakerloo line).
Eksterne henvisninger
Veje i London | danish | 1.172632 |
human_monogamy/Infidelity.txt | Infidelity (synonyms include cheating, straying, adultery, being unfaithful, two-timing, or having an affair) is a violation of a couple's emotional and/or sexual exclusivity that commonly results in feelings of anger, sexual jealousy, and rivalry.
What constitutes infidelity depends on expectations within the relationship. In marital relationships, exclusivity is commonly assumed. Infidelity can cause psychological damage, including feelings of rage and betrayal, low sexual and personal confidence, and even post-traumatic stress disorder. People of all genders can experience social consequences if their act of infidelity becomes public, but the form and extent of these consequences can depend on the gender of the unfaithful person.
Incidence[edit]
After the Kinsey Reports came out in the early 1950s, findings suggested that historically and cross-culturally, extramarital sex has been a matter of regulation more than sex before marriage. The Kinsey Reports found that around half of men and a quarter of women studied had committed adultery. The Janus Report on Sexual Behavior in America also reported that one-third of married men and a quarter of women have had an extramarital affair.
According to The New York Times, the most consistent data on infidelity comes from the University of Chicago's General Social Survey (GSS). Interviews with people in monogamous relationships since 1972 by the GSS have shown that approximately 12% of men and 7% of women admit to having had an extramarital relationship. Results, however, vary year by year, and also by age-group surveyed. For example, one study conducted by the University of Washington, Seattle, found slightly, or significantly higher, rates of infidelity for populations under 35, or older than 60. In that study, which involved 19,065 people during a 15-year period, rates of infidelity among men were found to have risen from 20% to 28%, and rates for women ranged from 5% to 15%. In more recent nationwide surveys, several researchers found that about twice as many men as women reported having an extramarital affair. A survey conducted in 1990 found that 2.2% of married participants reported having more than one partner during the past year. In general, national surveys conducted in the early 1990s reported that between 15 and 25% of married Americans reported having extramarital affairs. People who had stronger sexual interests, more permissive sexual values, lower subjective satisfaction with their partner, weaker network ties to their partner, and greater sexual opportunities were more likely to be unfaithful. Studies suggest around 30–40% of unmarried relationships and 18–20% of marriages see at least one incident of sexual infidelity.
Rates of infidelity among women are thought to increase with age. In one study, rates were higher in more recent marriages, compared with previous generations. Men were found to be only "somewhat" more likely than women to engage in infidelity, with rates for both sexes becoming increasingly similar. Another study found that the likelihood of women being involved in infidelity reached a peak in the seventh year of their marriage and then declined afterward. For married men, the longer they were in relationships, the less likely they were to engage in infidelity, until the eighteenth year of marriage, at which point the chance of men engaging in infidelity began to increase.
Research on pregnancy and its effects on sexual desire and rates of infidelity conducted in southern Spain indicated that men were more likely to engage in infidelity while their partner was pregnant. It was estimated that 1 in 10 fathers-to-be engaged in infidelity at some point during their partner's pregnancy and suggested that the likelihood of the man engaging in infidelity increases as the woman's pregnancy progresses through its trimesters.
One measure of infidelity is paternal discrepancy, a situation that arises when someone who is presumed to be a child's father is in fact not the biological parent. Frequencies as high as 30% are sometimes assumed in the media, but research by sociologist Michael Gilding traced these overestimates back to an informal remark at a 1972 conference. The detection of paternal discrepancy can occur in the context of medical genetic screening, in genetic family name research, and in immigration testing. Such studies show that paternal discrepancy is, in fact, less than 10% among the sampled African populations, less than 5% among the sampled Native American and Polynesian populations, less than 2% of the sampled Middle Eastern population, and generally 1–2% among European samples.
Gender[edit]
Differences in sexual infidelity as a function of gender have been commonly reported. It is more common for men compared to women to engage in extradyadic relationships. The National Health and Social Life Survey found that 4% of married men, 16% of cohabiting men, and 37% of dating men engaged in acts of sexual infidelity in the previous year compared to 1% of married women, 8% of cohabiting women, and 17% of women in dating relationships. These differences have been generally thought due to evolutionary pressures that motivate men towards sexual opportunity and women towards commitment to one partner (for reasons such as reproductive success, stability, and social expectations). In addition, recent research finds that differences in gender may possibly be explained by other mechanisms including power and sensations seeking. For example, one study found that some women in more financially independent and higher positions of power, were also more likely to be more unfaithful to their partners. In another study, when the tendency to sensation seek (i.e., engage in risky behaviours) was controlled for, there were no gender differences in the likelihood to being unfaithful. These findings suggest there may be various factors that might influence the likelihood of some individuals to engage in extradyadic relationships, and that such factors may account for observed gender differences beyond actual gender and evolutionary pressures associated with each.
Gender differences[edit]
There is currently debate in the field of evolutionary psychology whether an innate, evolved sex difference exists between men and women in response to an act of infidelity; this is often called a "sex difference". A study published in 2002 suggested there may be sex differences in jealousy. Those that posit a sex difference exists state that men are 60% more likely to be disturbed by an act of sexual infidelity (having one's partner engage in sexual relations with another), whereas women are 83% more likely to be disturbed by an act of emotional infidelity (having one's partner fall in love with another). Those against this model argue that there is no difference between men and women in their response to an act of infidelity. From an evolutionary perspective, men are theorized to maximize their fitness by investing as little as possible in their offspring and producing as many offspring as possible, due to the risk of males investing in children that are not theirs. Women, who do not face the risk of cuckoldry, are theorized to maximize their fitness by investing as much as possible in their offspring because they invest at least nine months of resources towards their offspring in pregnancy. Maximizing female fitness is theorized to require males in the relationship to invest all their resources in the offspring. These conflicting strategies are theorized to have resulted in selection of different jealousy mechanisms that are designed to enhance the fitness of the respective gender.
A common way to test whether an innate jealousy response exists between sexes is to use a forced-choice questionnaire. This style of questionnaire asks participants "yes or no" and "response A or response B" style questions about certain scenarios. For example, a question might ask, "If you found your partner cheating on you would you be more upset by (A) the sexual involvement or (B) the emotional involvement". Many studies using forced choice questionnaires have found statistically significant results supporting an innate sex difference between men and women. Furthermore, studies have shown that this observation holds across many cultures, although the magnitudes of the sex difference vary within sexes across cultures.
Although forced-choice questionnaires show a statistically significant sex-difference, critics of the theory of evolved sex differences in jealousy question these findings. In consideration of the entire body of work on sex differences, C. F. Harris asserted that when methods other than forced-choice questionnaires are used to identify an innate sex difference, inconsistencies between studies begin to arise. For example, researchers found that women sometimes report feeling more intense jealousy in response to both sexual and emotional infidelity. The results of these studies also depended on the context in which the participants were made to describe what type of jealousy they felt, as well as the intensity of their jealousy.
In her meta-analysis, Harris raises the question of whether forced choice questionnaires actually measure what they purport: jealousy itself and evidence that differences in jealousy arise from innate mechanisms. Her meta-analysis reveals that sex-differences are almost exclusively found in forced-choice studies. According to Harris, a meta-analysis of multiple types of studies should indicate a convergence of evidence and multiple operationalizations. This is not the case, which raises the question as to the validity of forced-choice studies. DeSteno and Bartlett (2002) further support this argument by providing evidence which indicates that significant results of forced-choice studies may actually be an artifact of measurement; this finding would invalidate many of the claims made by those "in favor" of an "innate" sex difference. Even those "in favor" of sex-differences admit that certain lines of research, such as homicide studies, suggest against the possibility of sex-differences.
These inconsistent results have led researchers to propose novel theories that attempt to explain the sex differences observed in certain studies. One theory that has been hypothesized to explain why men and women both report more distress to emotional infidelity than sexual infidelity is borrowed from childhood attachment theories. Studies have found that attachment styles of adults are consistent with their self-reported relationship histories. For example, more men are reported to have an insecure, dismissing avoidant attachment style; where these "individuals often attempt to minimize or constrict emotional experience, deny needs for intimacy, are highly invested in autonomy, and are more sexually promiscuous than individuals who have other attachment styles". Levy and Kelly (2010) tested this theory and found that adult attachment styles strongly correlate to which type of infidelity elicited more jealousy. Individuals who have secure attachment styles often report that emotional infidelity is more upsetting whereas dismissing attachment styles were more likely to find sexual infidelity more upsetting. Their study did report that men in general were more likely than women to report sexual infidelity as more distressing, however this could be related to more men having a dismissing attachment style.The authors propose that a social mechanism may be responsible for the observed results. In other words, replicable sex differences in emotion and sexual jealousy could be a function of a social function. Similar studies focusing on the masculinization and feminization by society also argue for a social explanation, while discounting an evolutionary explanation.
A 2015 study found a correlation between AVPR1A expression and predisposition to extrapair mating in women but not in men.
Sexual orientation[edit]
Evolutionary researchers have suggested that men and women have innate mechanisms that contribute to why they become sexually jealous, this is especially true for certain types of infidelity. It has been hypothesized that heterosexual men have developed an innate psychological mechanism that responds to the threat of sexual infidelity more than emotional infidelity, and vice versa for heterosexual women because potential cuckoldry is more detrimental to the male, who could potentially invest in offspring of another male, while for females emotional infidelity is more worrisome because they could lose the parental investment to another woman's offspring, therefore affecting their chances of survival. However, more recent studies suggest that increasingly both men and women would find emotional infidelity psychologically worse.
Symons (1979) determined that sexual jealousy is the major reason that many homosexual men are unsuccessful in maintaining monogamous relationships and suggests that all men are innately disposed to want sexual variation, with the difference between heterosexual and homosexual men being that homosexual men can find willing partners more often for casual sex, and thus satisfy this innate desire for sexual variety. However, according to this view, all men can be "hard wired" to be sexually jealous, and therefore gay men could be more upset by sexual infidelity than by emotional infidelity, and that lesbians could be more upset by emotional infidelity than sexual. Recent studies suggest that it may not be an innate mechanism, rather depends on the importance placed on sexual exclusivity. Peplau and Cochran (1983) found that sexual exclusivity was much more important to heterosexual men and women compared to homosexual men and women. This theory suggests that it is not sexuality that may lead to differences but that people are prone to jealousy in domains that are especially important to them. Barah and Lipton argue that heterosexual couples may cheat just as much as homosexual relationships.
Harris (2002) tested these hypotheses among 210 individuals: 48 homosexual women, 50 homosexual men, 40 heterosexual women, and 49 heterosexual men. Results found that more heterosexual than homosexual individuals picked sexual infidelity as worse than emotional infidelity, with heterosexual men being the highest, and that when forced to choose, gay men overwhelmingly predicted emotional infidelity would be more troubling than sexual infidelity. These findings contradict Symons (1979) suggestion that there would be no gender difference in predicted responses to infidelity by sexual orientation. Blow and Bartlett (2005) suggest that even though sex outside of a homosexual relationship might be seen as more acceptable in some relationships, the consequences of infidelity do not occur without pain or jealousy.
Heterosexuals rated emotional and sexual infidelity as more emotionally distressing than did lesbian and gay individuals. Sex and sexual orientation differences emerged regarding the degree to which specific emotions were reported in response to sexual and emotional infidelity. Few researchers have explored the influence of sexual orientation on which type of infidelity is viewed as more distressing.
Summarizing the findings from these studies, heterosexual men seem to be more distressed by sexual infidelity than heterosexual women, lesbian women, and gay men. These latter three groups seem more responsible for this difference by reporting similarly higher levels of distress toward emotional infidelity than heterosexual men. However, within-sex analyses reveal that heterosexual men tend to rate emotional infidelity as more distressing than sexual infidelity.
Responses[edit]
Some studies suggest that only a small percentage of couples that experience infidelity actually improve their relationship, whereas others report couples having surprisingly positive relationship outcomes. In terms of negative responses to infidelity, Charney and Parnass (1995) report that after hearing of a partner's infidelity, reactions have included rage and increased aggressiveness, loss of trust, decreased personal and sexual confidence, sadness, depression, damaged self-esteem, fear of abandonment, and a surge of justification to leave their partner. Another study reported that nearly 60% of the partners that were cheated on had emotional problems and depression following disclosure of the affair. Other negative consequences have included damage to relationships with children, parents, and friends, as well as legal consequences. A report in 1983 detailed that of a sample of 205 divorced individuals, about one half said their marital problems were caused by their spouse's infidelity.
The negative impact of infidelity on a relationship depends on how involved partners are in their infidelity relationship, and researchers maintain that infidelity itself does not cause divorce but the overall level of relationship satisfaction, motives for infidelity, level of conflict, and attitudes held about infidelity do. In fact, Schneider, et al. (1999) reported that even though 60% of their participants initially threatened to leave their primary relationship, a threat to leave due to infidelity did not actually predict the eventual outcome. Atkins, Eldridge, Baucom, and Christiansen found that couples who went through therapy as well as openly dealt with the infidelity were able to change at a faster rate than distressed couples who were just in therapy. Some unintended positive outcomes that have been reported for couples experiencing infidelity include closer marital relationships, increased assertiveness, taking better care of oneself, placing higher value on family, and realizing the importance of marital communication.
If divorce results from infidelity, research suggest that the "faithful" spouse may experience feelings of low life satisfaction and self-esteem; they may also engage in future relationships fearful of the same incidence occurring. Sweeney and Horwitz (2001) found that individuals who initiated a divorce after hearing about their partner's infidelity experienced less depression; however, the opposite was true when the offending spouse initiated divorce.
According to attachment theory, intimates evaluate the availability of close others and respond to them accordingly. While those with a secure attachment style believe others are available to them, those with insecure attachment believe others are less available to them. People who develop high levels of attachment have more anxiety and uncertainty. They cope by seeking reassurance and clinging themselves to another person. In attachment theory, people seek sex to help meet their needs. Those whose partners are unfaithful may experience anxiety, stress and depression. They are more likely to engage in activities that are risky to their health. Women who experienced negative appraisals, like self-blame and causal attribution, led to emotional distress and increased health-compromising behavior.
Gender self-esteem greatly affects infidelity. Different factors for the two genders are known to influence jealousy. Heterosexual men seem to be more distressed by sexual infidelity than heterosexual women, lesbian women, and gay men. The latter three groups seem more responsible for the difference by reporting similarly higher levels of distress toward emotional infidelity than heterosexual men.
Causes[edit]
Studies have found that men are more likely to engage in extramarital sex if they are unsatisfied sexually, while women are more likely to engage in extramarital sex if they are unsatisfied emotionally. Kimmel and Van Der Veen found that sexual satisfaction may be more important to husbands and that wives are more concerned with compatibility with their partners. Studies suggest that individuals who can separate concepts of sex and love are more likely to accept situations where infidelity occurs. One study done by Roscoe, Cavanaugh, and Kennedy found that women indicated relationship dissatisfaction as the number one reason for infidelity, whereas men reported a lack of communication, understanding, and sexual incompatibility. Glass and Wright also found that men and women who are involved in both sexual and emotional infidelities reported being the most dissatisfied in their relationships than those who engaged in either sexual or emotional infidelity alone. In general, marital dissatisfaction overall is the number one reason often reported for infidelity for both sexes.
It is important to note that there are many other factors that increase the likelihood of anyone engaging in infidelity. Individuals exhibiting sexually permissive attitudes and those who have had a high number of past sexual relationships are also more likely to engage in infidelity. Other factors such as being well educated, living in an urban centre, being less religious, having a liberal ideology and values, having more opportunities to meet potential partners, and being older affected the likelihood of one being involved in an extramarital affair.
Anthropological viewpoint[edit]
Anthropologists tend to believe humans are neither completely monogamous nor completely polygamous. Anthropologist Bobbi Low says we are "slightly polygamous", while Deborah Blum believes we are "ambiguously monogamous", and slowly moving away from the polygamous habits of our evolutionary ancestors.
According to anthropologist Helen Fisher, there are numerous psychological reasons for adultery. Some people may want to supplement a marriage, solve a sex problem, gather more attention, seek revenge, or have more excitement in the marriage. But based on Fisher's research, there also is a biological side to adultery. "We have two brain systems: one of them is linked to attachment and romantic love, and then there is the other brain system, which is purely sex drive." Sometimes these two brain systems are not well-connected, which enables people to become adulterers and satisfy their libido without any regards to their attachment side.
Cultural variation[edit]
Often, gender differences in both jealousy and infidelity are attributable to cultural factors. This variation stems from the fact that societies differ in how they view extramarital affairs and jealousy. An examination of jealousy across seven nations revealed that each partner in a relationship serves as each other's primary and exclusive source of satisfaction and attention in all cultures. Therefore, when an individual feels jealousy towards another, it is usually because they are now sharing their primary source of attention and satisfaction. However, variation can be seen when identifying the behaviors and actions that betray the role of primary attention (satisfaction) giver. For instance, in certain cultures if an individual goes out with another of the opposite gender, emotions of intense jealousy can result; however, in other cultures, this behavior is perfectly acceptable and is not given much thought.
It is important to understand where these cultural variations come from and how they root themselves into differing perceptions of infidelity. While many cultures report infidelity as wrong and admonish it, some are more tolerant of such behaviour. These views are generally linked to the overall liberal nature of the society. For instance, Danish society is viewed as more liberal than many other cultures, and as such, have correlating liberal views on infidelity and extramarital affairs. According to Christine Harris and Nicholas Christenfeld, societies that are legally more liberal against extramarital affairs judge less harshly upon sexual infidelity because it is distinct from emotional infidelity. In Danish society, having sex does not necessarily imply a deep emotional attachment. As a result, infidelity does not carry such a severe negative connotation. A comparison between modern-day Chinese and American societies showed that there was greater distress with sexual infidelity in the U.S. than in China. The cultural difference is most likely due to the more restrictive nature of Chinese society, thus, making infidelity a more salient concern. Sexual promiscuity is more prominent in the United States, thus it follows that American society is more preoccupied with infidelity than Chinese society. Often, a single predominant religion can influence the culture of an entire nation. Even within Christianity in the United States, there are discrepancies as to how extramarital affairs are viewed. For instance, Protestants and Catholics do not view infidelity with equal severity. The conception of marriage is also markedly different; while in Roman Catholicism marriage is seen as an indissoluble sacramental bond and does not permit divorce even in cases of infidelity, most Protestant denominations allow for divorce and remarriage for infidelity or other reasons. Ultimately, it was seen that adults that associated with a religion (any denomination) were found to view infidelity as much more distressing than those who were not affiliated with a religion. Those that participated more heavily in their religions were even more conservative in their views on infidelity.
Some research has also suggested that being African American has a positive correlation to infidelity, even when education attainment is controlled for. Other research suggests that lifetime incidence of infidelity does not differ between African Americans and whites, only the likelihood of when they engage in it. Race and gender have been found to be positively correlated with infidelity, however this is the case more often for African American men engaging in extramarital infidelity. Human mating strategies differ from culture to culture. For example, Schmitt discusses how tribal cultures with higher pathogen stress are more likely to have polygynous marriage systems; whereas monogamous mating systems usually have relatively lower high-pathogen environments. In addition researchers have also proposed the idea that high mortality rates in local cultures should be correlated with more permissive mating strategies. On the other hand, Schmitt discusses how demanding reproductive environments should increase the desire and pursuit of biparental, monogamous relationships.
Strategic pluralism theory[edit]
Strategic pluralism is a theory that focuses on how environmental factors influence mating strategies. According to this theory, when people live within environments that are demanding and stressful, the need for bi-parental care is greater for increasing the survival of offspring. Correspondingly, monogamy and commitment are more commonplace. On the other hand, when people live within environments that encompass little stress and threats to the viability of offspring, the need for serious and committed relations is lowered, and therefore promiscuity and infidelity are more common.
Sex-ratio theory[edit]
Sex ratio theory is a theory that explains the relationship and sexual dynamics within different areas of the world based on the ratio of the number of marriage-aged men to marriage-aged women. According to this theory, an area has a high sex ratio when there is a higher number of marriage-aged women to marriage-aged men and an area has a low sex ratio when there are more marriage-aged men. In terms of infidelity, the theory states that when sex ratios are high, men are more likely to be promiscuous and engage in sex outside of a committed relationship because the demand for men is higher and this type of behavior, desired by men, is more accepted. On the other hand, when sex ratios are low, promiscuity is less common because women are in demand and since they desire monogamy and commitment, in order for men to remain competitive in the pool of mates, they must respond to these desires. Support for this theory comes from evidence showing higher divorce rates in countries with higher sex ratios and higher monogamy rates in countries with lower sex ratios.
Other contributing factors[edit]
While infidelity is by no means exclusive to certain groups of people, its perception can be influenced by other factors. Furthermore, within a "homogeneous culture", like that in the United States, factors like community size can be strong predictors of how infidelity is perceived. Larger communities tend to care less about infidelity whereas small towns are much more concerned with such issues. These patterns are observed in other cultures as well. For example, a cantina in a small, rural Mexican community is often viewed as a place where "decent" or "married" women do not go because of its semi-private nature. Conversely, public spaces like the market or plaza are acceptable areas for heterosexual interaction. A smaller population size presents the threat of being publicly recognized for infidelity. However, within a larger community of the same Mexican society, entering a bar or watering hole would garner a different view. It would be deemed perfectly acceptable for both married and unmarried individuals to drink at a bar in a large city. These observations can be paralleled to rural and urban societies in the United States as well. Ultimately, these variables and societal differences dictate attitudes towards sexual infidelity which can vary across cultures as well as within cultures.
"Mate poaching" is the phenomenon of a single person luring a person who is in an intimate relationship to leave their partner for the single person. According to a survey of 16,964 individuals in 53 countries by David Schmitt (2001), mate poaching happens significantly more frequently in Middle Eastern countries such as Turkey and Lebanon, and less frequently in East Asian countries such as China and Japan.
Evolutionary factors[edit]
The parental investment theory is used to explain evolutionary pressures that can account for sex differences in infidelity. This theory states that the sex that invests less in the offspring has more to gain from indiscriminate sexual behaviour. This means that women, who typically invest more time and energy into raising their offspring (9 months of carrying offspring, breast feeding etc.), should be more choosy when it comes to mate selection and should therefore desire long-term, monogamous relationships that would ensure the viability of their offspring. Men on the other hand, have less parental investment and so they are driven towards indiscriminate sexual activity with multiple partners as such activity increases the likelihood of their reproduction. This theory says that it is these evolutionary pressures that act on men and women differentially and what ultimately drives more men to seek sexual activity outside of their own relationships. It can however, still account for the occurrence of extradyadic sexual relationships among women. For example, a woman whose husband has fertilization difficulties can benefit from engaging in sexual activity outside of her relationship. She can gain access to high-quality genes and still derive the benefit of parental investment from her husband or partner who is unknowingly investing in their illegitimate child. Evidence for the development of such a short-term mating strategy in women comes from findings that women who engage in affairs typically do so with men who are of higher status, dominance, physical attractiveness (which is indicative of genetic quality).
Defense mechanisms[edit]
One defense mechanism that some researchers believe is effective at preventing infidelity is jealousy. Jealousy is an emotion that can elicit strong responses. Cases have been commonly documented where sexual jealousy was a direct cause of murders and morbid jealousy. Buss (2005) states that jealousy has three main functions to help prevent infidelity. These suggestions are:
It can alert an individual to threats with a valued relationship.
It can be activated by the presence of interested and more desirable intrasexual rivals.
It can function as a motivational mechanism that creates behavioral outputs to deter infidelity and abandonment.
Looking at jealousy's physiological mechanism offers support for this idea. Jealousy is a form of stress response which has been shown to activate the sympathetic nervous system by increasing heart rate, blood pressure, and respiration. This will activate the "fight or flight" response to ensure action against the attempt at sexual infidelity in their partner. Buss and his colleagues were the first to pioneer a theory that jealousy is an evolved human emotion that has become an innate module, hard-wired to prevent infidelity from occurring. This idea is commonly referred to as Jealousy as a Specific Innate Module and has become widely debated. The basis behind this argument is that jealousy was beneficial in our ancestor's time when cuckoldry was more common. They suggested that those who were equipped with this emotional response could more effectively stop infidelity and those without the emotional response had a harder time doing so. Because infidelity imposed such a fitness cost, those who had the jealous emotional response, improved their fitness, and could pass down the jealousy module to the next generation.
Another defense mechanism for preventing infidelity is by social monitoring and acting on any violation of expectations. Researchers in favor of this defense mechanism speculate that in our ancestor's times, the act of sex or emotional infidelity is what triggered jealousy and therefore the signal detection would have happened only after infidelity had occurred, making jealousy an emotional by-product with no selective function. In line with this reasoning, these researchers hypothesize that as a person monitors their partner's actions with a potential rival through primary and secondary appraisals; if their expectations are violated at either level of observation, they will become distressed and enact an appropriate action to stop the chance of infidelity. Social monitoring therefore enables them to act accordingly before infidelity occurs, thereby having the capability to raise their fitness. Research testing this theory has found more favor for the sexual jealousy hypothesis.
A more recently suggested defense mechanism of infidelity attracting more attention is that a particular social group will punish cheaters by damaging their reputation. The basis for this suggestion stems from the fact that humans have an unmatched ability to monitor social relationships and inflict punishment on cheaters, regardless of the context. This punishment comes in many forms, one of which is gossip. This damage will impair the future benefits that individual can confer from the group and its individuals. A damaged reputation is especially debilitating when related to sexual and emotional infidelity, because it can limit future reproductive mate choices within the group and will cause a net fitness cost that outweighs the fitness benefit gained from the infidelity. Such limitations and costs deter an individual from cheating in the first place. Support for this defense mechanism comes from fieldwork by Hirsch and his colleagues (2007) that found that gossip about extramarital affairs in a small community in Mexico was particularly prevalent and devastating for reputation in this region. Specifically, adultery was found to cause an individual to be disowned by their family, decrease the marriage value of his/her family, cause an individual to lose money or a job, and diminish future reproductive potential. In this community, men having extramarital affairs did so in private areas with lower prevalence of women connected to the community, such as bars and brothels, both areas of which had a high risk of contracting sexually transmitted infections.
The Internet[edit]
The proliferation of sex chat rooms and dating apps has increased the opportunity for people in committed relationships to engage in acts of infidelity on and off the Internet. A cyber affair is defined as "a romantic or sexual relationship initiated by online contact and maintained primarily via online communication". Sexual acts online include behaviors such as cybersex, where two or more individuals engage in discussions about sexual fantasies over the Internet and is usually accompanied by masturbation; hot-chatting, where discussions between two or more people move away from light-hearted flirting; and emotional acts where people disclose intimate information to a significant other. A new type of sexual activity online is when two people's avatars engage in sexual activity in virtual reality worlds such as Second Life. The majority of Americans believe that if a partner engaged in cybersex this constitutes as an act of infidelity.
A 2005 survey of 1828 participants reported one third of them reported engaging in cybersex and of that one third, 46% said they were in a committed relationship with someone else.
In an attempt to differentiate offline and online infidelity, Cooper, Morahan-Martin, Mathy, and Maheu constructed a "Triple-A Engine", which identifies the three aspects of Internet infidelity that distinguish it, to some degree, from traditional infidelity:
Accessibility: the more access one has to the Internet, the more likely they will engage in infidelity
Affordability: the monetary cost of being able to access the Internet continues to drop, and for a small price, a user can visit many sites, and meet multiple potential sexual needs
Anonymity: the Internet allows users to masquerade as someone else, or hide their identity altogether.
In a study of 335 Dutch undergraduate students involved in serious intimate relationships, participants were presented with four dilemmas concerning a partner's emotional and sexual infidelity over the Internet. They found a significant sex difference as to whether participants chose sexual and emotional infidelity as more upsetting. More men than women indicated that a partner's sexual involvement would upset them more than a partner's emotional bonding with someone else. Similarly, in the dilemma involving infidelity over the Internet, more men indicated their partner's sexual involvement would upset them more than a partner's emotional bonding with someone else. Women, on the other hand, expressed more problems with emotional infidelity over the Internet than did men.
Online infidelity can be just as damaging to a relationship as offline physical unfaithfulness. A possible explanation is that our brain registers virtual and physical acts the same way and responds similarly. Several studies have concluded that online infidelity, whether sexual or emotional in nature, often leads to off-line infidelity.
Chat rooms[edit]
A study by Beatriz Lia Avila Mileham in 2004 examined the phenomenon of online infidelity in chat rooms. The following factors were investigated: what elements and dynamics online infidelity involves and how it happens; what leads individuals specifically to the computer to search for a relationship on the side; whether individuals consider online contacts as infidelity and why or why not; and what dynamics chat room users experience in their marriages. The results led to three constructs that symbolize chat room dynamics and serve as a foundation for Internet infidelity:
Anonymous sexual interactionism: the individuals' predilection for anonymous interactions of a sexual nature in chat rooms. The allure of anonymity gains extra importance for married individuals, who can enjoy relative safety to express fantasies and desires without being known or exposed.
Behavioral rationalization: the reasoning that chat room users present for conceiving their online behaviors as innocent and harmless, despite the secrecy and highly sexual nature.
Effortless avoidance: chat room users' lack of psychological discomfort in exchanging sexual messages with strangers.
Legal implications[edit]
See also: Adultery § Law
All countries in Europe, as well as most countries in Latin America have decriminalized adultery; however, in many countries in Africa and Asia (particularly the Middle East) this type of infidelity is criminalized. Even where infidelity is not a criminal offense, it may have legal implications in divorce cases; for example it may be a factor in property settlement, the custody of children, the denial of alimony, etc. In civil claims, not only the spouse, but also the "other man/other woman" may be held accountable: for example, seven US states (Hawaii, Illinois, North Carolina, Mississippi, New Mexico, South Dakota, and Utah) allow the possibility of the tort action of alienation of affections (brought by a deserted spouse against a third party alleged to be responsible for the failure of the marriage). In a highly publicized case in 2010, a woman in North Carolina won a $9 million suit against her husband's mistress. In the United States, criminal laws relating to infidelity vary, and those states that criminalize adultery rarely prosecute the offense. Penalties for adultery range from life imprisonment in Michigan, to a $10 fine in Maryland or class 1 felony in Wisconsin. The constitutionality of US criminal laws on adultery is unclear due to Supreme Court decisions in 1965 giving privacy of sexual intimacy to consenting adults, as well as broader implications of Lawrence v. Texas (2003). Adultery is declared to be illegal in 21 states.
In many jurisdictions, adultery may have indirect legal implications, particularly in cases of infliction of violence, such as domestic assaults and killings, in particular by mitigating murder to manslaughter, or otherwise providing for partial or complete defenses in case of violence, especially in cultures where there is a traditional toleration of crimes of passion and honor killings. Such provisions have been condemned by the Council of Europe and the United Nations in recent years. The Council of Europe Recommendation Rec(2002)5 of the Committee of Ministers to member states on the protection of women against violence states that member states should: "(...) 57. preclude adultery as an excuse for violence within the family." UN Women has also stated in regard to the defense of provocation and other similar defenses: "Laws should clearly state that these defenses do not include or apply to crimes of 'honour', adultery, or domestic assault or murder."
Workplace issues[edit]
As the number of women in the workforce increases to match that of men, researchers expect the likelihood of infidelity will also increase with workplace interactions. Wiggins and Lederer (1984) found that opportunities to engage in infidelity were related to the workplace where nearly one half of their samples who engaged in infidelity were involved with coworkers. A study done by McKinnish (2007) found that those who work with a larger fraction of workers of the opposite sex are more likely to be divorced due to infidelity. Kuroki found that married women were less likely to have a workplace affair, whereas self-employed individuals are more likely. In 2000, Treas and Giesen found similar results where sexual opportunities in the workplace increased the likelihood of infidelity during the last 12 months.
Adulterous office romances are widely considered to be unhelpful to business and work relationships, and superior-subordinate relationships are banned in 90% of companies with written policies regarding office romance. Companies cannot ban adultery, as, in all but a handful of states, such regulations would run afoul of laws prohibiting discrimination on the basis of marital status. Firings nonetheless often occur on the basis of charges of inappropriate office conduct.
Academics and therapists say cheating is probably more prevalent on the road than close to home. The protection of the road offers a secret life of romance, far from spouses or partners. Affairs range from one-night stands to relationships that last for years. They are usually with a co-worker, a business associate or someone they repeatedly encounter.
Another reason for the development of office romances is the amount of time co-workers spend together. Spouses today often spend more time with co-workers in the office than with each other. A Newsweek article notes, "Nearly 60 percent of American women work outside the home, up from about 40 percent in 1964. Quite simply, women intersect with more people during the day than they used to. They go to more meetings, take more business trips and, presumably, participate more in flirtatious water-cooler chatter."
According to Debra Laino in an article for Shave, some of the reasons women cheat at the workplace are because "women are disproportionately exposed to men in the workplace, and, as a direct consequence, many have more options and chances to cheat."
Alternative views (swinging and polyamory)[edit]
Swinging is a form of extradyadic sex where married couples exchange partners with each other. Swinging was originally called "wife-swapping", but due to the sexist connotations and the fact that many wives were willing to swap partners, "mate swapping" and or "swinging" was substituted. The Supreme Court of Canada has ruled swinging is legal as long as it takes place in a private place and is consensual. Swinging can be closed or open, where couples meet and each pair goes off to a separate room or they have sex in the same room. The majority of swingers fall into the middle and upper classes, with an above average education and income, and majority of these swingers are white (90%). A study done by Jenks in 1986 found that swingers are not significantly different from non-swingers on measures such as philosophy, authoritarianism, self-respect, happiness, freedom, equality etc. Swingers tend to emphasize personal values over more social ones. According to Henshel (1973), the initiation into the world of swinging usually is done by the husband.
Reasons for getting involved in swinging are the variety of sexual partners and experiences, pleasure or excitement, meeting new people, and voyeurism. In order for swinging to work, both partners need to have a liberal sexual predisposition, and a low degree of jealousy. Gilmartin (1975) found that 85% of his sample of swingers felt that these sexual encounters posed no real threat to their marriage and felt it had improved. Jenks (1998) found no reason to believe that swinging was detrimental to marriage, with over 91% of males and 82% of females indicating they were happy with swinging.
Another form of extradyadic sex is polyamory, a "non-possessive, honest, responsible and ethical philosophy and practice of loving multiple people simultaneously". There are various types of relationships in polyamory such as intentional family, group relationship, and group marriage. One type of group relationship can be a triad involving a married couple and an additional person who all share sexual intimacy, however, it is usually an addition of a female. Unlike polygyny or polyandry, both men and women may have multiple partners within the confines of polyamory. Polyamorous relationships are distinguished from extramarital affairs by the full disclosure and consent of all involved. Polyamorous relationships may specify unique boundaries outside monogamous expectations of fidelity, that if violated are still considered cheating. Because both men and women can have multiple partners, these individuals do not consider themselves to be either uncommitted or unfaithful.
See also[edit]
Crime of passion
Cuckold and Cuckquean
Emotional affair
Financial infidelity
Fornication
Open marriage
Polygyny threshold model
Relational transgressions
Seduction
Zina
Notes[edit]
^ "How Infidelity Causes Post Traumatic Stress Disorder | Psychology Today". www.psychologytoday.com. Retrieved 2021-06-01.
^ Boyce, Sabrina; Zeledón, Perla; Tellez, Ever; Barrington, Clare (April 2016). "Gender-Specific Jealousy and Infidelity Norms as Sources of Sexual Health Risk and Violence Among Young Coupled Nicaraguans". American Journal of Public Health. 106 (4): 625–632. doi:10.2105/AJPH.2015.303016. ISSN 0090-0036. PMC 4816077. PMID 26890184.
^ Christensen, H. T. (1 March 1962). "A Cross-Cultural Comparison of Attitudes Toward Marital Infidelity". International Journal of Comparative Sociology. 3 (1): 124–137. doi:10.1177/002071526200300112. S2CID 220874833.
^ Greeley, Andrew (May 1994). "Marital infidelity". Society. 31 (4): 9–13. doi:10.1007/bf02693241. S2CID 189887196.
^ Parker-Pope, Tara (28 October 2008). "Love, sex and the changing landscape of infidelity". The New York Times.
^ Wiederman, Michael W. (January 1997). "Extramarital sex: Prevalence and correlates in a national survey". Journal of Sex Research. 34 (2): 167–174. doi:10.1080/00224499709551881.
^ Choi, K H; Catania, J A; Dolcini, M M (December 1994). "Extramarital sex and HIV risk behavior among US adults: results from the National AIDS Behavioral Survey". American Journal of Public Health. 84 (12): 2003–2007. doi:10.2105/ajph.84.12.2003. PMC 1615405. PMID 7998648.
^ Treas, Judith; Giesen, Deirdre (February 2000). "Sexual Infidelity Among Married and Cohabiting Americans". Journal of Marriage and Family. 62 (1): 48–60. doi:10.1111/j.1741-3737.2000.00048.x.
^ Blow, Adrian J.; Hartnett, Kelley (April 2005). "Infidelity in Committed Relationships II: A Substantive Review". Journal of Marital and Family Therapy. 31 (2): 217–233. doi:10.1111/j.1752-0606.2005.tb01556.x. PMID 15974059.
^ Liu, Chien (May 2000). "A Theory of Marital Sexual Life". Journal of Marriage and Family. 62 (2): 363–374. doi:10.1111/j.1741-3737.2000.00363.x.
^ Fernández-Carrasco, Francisco Javier; Rodríguez-Díaz, Luciano; González-Mey, Urbano; Vázquez-Lara, Juana María; Gómez-Salgado, Juan; Parrón-Carreño, Tesifón (14 February 2020). "Changes in Sexual Desire in Women and Their Partners during Pregnancy". Journal of Clinical Medicine. 9 (2): 526. doi:10.3390/jcm9020526. ISSN 2077-0383. PMC 7074242. PMID 32075159.
^ Gilding, Michael (2005). "Rampant misattributed paternity: the creation of an urban myth". People and Place. 13 (12): 1–11.
^ Gilding, Michael (February 2009). "Paternity Uncertainty and Evolutionary Psychology: How a Seemingly Capricious Occurrence Fails to Follow Laws of Greater Generality". Sociology. 43 (1): 140–157. doi:10.1177/0038038508099102. S2CID 145367552.
^ Philipp EE (1973) "Discussion: moral, social and ethical issues". In: Wolstenholme GEW, Fitzsimons DW, eds. Law and ethics of AID and embryo transfer. Ciba Foundation symposium. Vol 17. London: Associated Scientific 63–66
^ Bellis MA, Hughes K, Hughes S, Ashton JR (September 2005). "Measuring paternal discrepancy and its public health consequences". J Epidemiol Community Health. 59 (9): 749–54. doi:10.1136/jech.2005.036517. PMC 1733152. PMID 16100312.
^ Sykes, B; Irven, C (2000). "Surnames and the Y chromosome". Am J Hum Genet. 66 (4): 1417–1419. doi:10.1086/302850. PMC 1288207. PMID 10739766.
^ King, T. E.; Jobling, M. A. (1 May 2009). "Founders, Drift, and Infidelity: The Relationship between Y Chromosome Diversity and Patrilineal Surnames". Molecular Biology and Evolution. 26 (5): 1093–1102. doi:10.1093/molbev/msp022. PMC 2668828. PMID 19204044.
^ Forster, P; Hohoff, C; Dunkelmann, B; Schürenkamp, M; Pfeiffer, H; Neuhuber, F; Brinkmann, B (2015). "Elevated germline mutation rate in teenage fathers". Proc Biol Sci. 282 (1803): 20142898. doi:10.1098/rspb.2014.2898. PMC 4345458. PMID 25694621.
^ Lalasz, C. B.; Weigel, D. J. (2011). "Understanding the relationship between gender and extradyadic relations: The mediating role of sensation seeking on intentions to engage in sexual infidelity". Personality and Individual Differences. 50 (7): 1079–1083. doi:10.1016/j.paid.2011.01.029.
^ Lammers, J.; Stoker, J. I.; Jordan, J.; Pollmann, M.; Stapel, D. A. (2011). "Power increases infidelity among men and women". Psychological Science. 22 (9): 1191–1197. doi:10.1177/0956797611416252. PMID 21771963. S2CID 11385458.
^ DeSteno, D.; Bartlett, M. Y.; Braverman, J.; Salovey, P. (2002). "Sex differences in jealousy: Evolutionary mechanism or artifact of measurement?" (PDF). Journal of Personality and Social Psychology. 83 (5): 1103–1116. CiteSeerX 10.1.1.616.5778. doi:10.1037/0022-3514.83.5.1103. PMID 12416915. S2CID 10537789. Archived from the original (PDF) on 2018-07-30.
^ Buss, D. M.; Larsen, R. J.; Westen, D.; Semmelroth, J. (1992). "Sex Differences in Jealousy—Evolution, Physiology, and Psychology". Psychological Science. 3 (4): 251–255. doi:10.1111/j.1467-9280.1992.tb00038.x. S2CID 27388562.
^ Miller, S. L.; Maner, J. K. (2009). "Sex differences in response to sexual versus emotional infidelity: The moderating role of individual differences". Personality and Individual Differences. 46 (3): 287–291. doi:10.1016/j.paid.2008.10.013.
^ Murphy, S. M.; Vallacher, R. R.; Shackelford, T. K.; Bjorklund, D. F.; Yunger, J. L. (2006). "Relationship experience as a predictor of romantic jealousy". Personality and Individual Differences. 40 (4): 761–769. doi:10.1016/j.paid.2005.09.004.
^ Buunk, B. P.; Angleitner, A.; Oubaid, V.; Buss, D. M. (1996). "Sex differences in jealousy in evolutionary and cultural perspective: Tests from the Netherlands, Germany, and the United States". Psychological Science. 7 (6): 359–363. doi:10.1111/j.1467-9280.1996.tb00389.x. S2CID 27485391.
^ Harris, C. R. (2003). "A review of sex differences in sexual jealousy, including self-report data, psychophysiological responses, interpersonal violence, and morbid jealousy". Personality and Social Psychology Review. 7 (2): 102–128. doi:10.1207/S15327957PSPR0702_102-128. PMID 12676643. S2CID 7357390.
^ Sagarin, B. J. (2005). "Reconsidering evolved sex differences in jealousy: Comment on Harris (2003)". Personality and Social Psychology Review. 9 (1): 62–75. doi:10.1207/s15327957pspr0901_5. PMID 15745865. S2CID 10951706.
^ Levy, K. N.; Blatt, S. J.; Shaver, P. R. (1998). "Attachment styles and parental representations". Journal of Personality and Social Psychology. 74 (2): 407–419. doi:10.1037/0022-3514.74.2.407.
^ Levy, K. N.; Kelly, K. M. (2010). "Sex differences in jealousy A contribution from attachment theory". Psychological Science. 21 (2): 168–173. doi:10.1177/0956797609357708. PMID 20424039. S2CID 206584973.
^ Ward, J.; Voracek, M. (2004). "Evolutionary and social cognitive explanations of sex differences in romantic jealousy". Australian Journal of Psychology. 56 (3): 165–171. doi:10.1080/00049530412331283381.
^ Zietsch, Brendan P.; Westberg, Lars; Santtila, Pekka; Jern, Patrick (2015). "Genetic analysis of human extrapair mating: heritability, between-sex correlation, and receptor genes for vasopressin and oxytocin" (PDF). Evolution & Human Behavior. 36 (2): 130–136. doi:10.1016/j.evolhumbehav.2014.10.001. We find strong genetic effects on extrapair mating in women and, for the first time, in men.
^ Harris, Christine R. (2004). "The Evolution of Jealousy: Did men and women, facing different selective pressures, evolve different "brands" of jealousy? Recent evidence suggests not". American Scientist. 92 (1): 62–71. doi:10.1511/2004.1.62. JSTOR 27858334.
^ Schmitt, D. P. (2005). "Sociosexuality from Argentina to Zimbabwe: A 48-nation study of sex, culture, and strategies of human mating". Behavioral and Brain Sciences. 28 (2): 247–274. doi:10.1017/s0140525x05000051. PMID 16201459. S2CID 25458417.
^ Harris, C. R. (2002). "Sexual and romantic jealousy in heterosexual and homosexual adults". Psychological Science. 13 (1): 7–12. doi:10.1111/1467-9280.00402. PMID 11892782. S2CID 18815461.
^ Salovey, Peter (1991). The Psychology of Jealousy and Envy. Guilford Press. pp. 271–286. ISBN 978-0-89862-555-4.
^ Barash & Lipton, D.P. & J.E. (2001). The Myth of Monogamy: Fidelity and Infidelity in Animals and People. New York: Henry Holt.
^ Leeker, O.; Carlozzi, A. (2012). "Effects of sex, sexual orientation, infidelity expectations, and love on distress related to emotional and sexual infidelity". Journal of Marital and Family Therapy. 40 (1): 68–91. doi:10.1111/j.1752-0606.2012.00331.x. hdl:11244/7190. PMID 25059413.
^ "After Infidelity". Psychology Today. Retrieved 2017-11-09.
^ Schneider, J. P.; Irons, R. R.; & Corley, M. D. (1999). "Disclosure of extramarital sexual activities by sexually exploitative professionals and other persons with addictive or compulsive sexual disorders". Journal of Sex Education and Therapy. 24 (4): 277–288. doi:10.1080/01614576.1999.11074316.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^ Mikulincer, Mario; Florian, Victor; Hirschberger, Gilad (February 2003). "The Existential Function of Close Relationships: Introducing Death Into the Science of Love". Personality and Social Psychology Review. 7 (1): 20–40. doi:10.1207/s15327957pspr0701_2. PMID 12584055. S2CID 11600574.
^ Russell, V. Michelle; Baker, Levi R.; McNulty, James K. (2013). "Attachment insecurity and infidelity in marriage: Do studies of dating relationships really inform us about marriage?". Journal of Family Psychology. 27 (2): 242–251. doi:10.1037/a0032118. PMC 3648986. PMID 23544923.
^ Shrout, M. Rosie; Weigel, Daniel J. (2017-04-21). "Infidelity's aftermath: Appraisals, mental health, and health-compromising behaviors following a partner's infidelity". Journal of Social and Personal Relationships. 35 (8): 1067–1091. doi:10.1177/0265407517704091. S2CID 151439845.
^ Goldenberg, Jamie L.; Landau, Mark J.; Pyszczynski, Tom; Cox, Cathy R.; Greenberg, Jeff; Solomon, Sheldon; Dunnam, Heather (December 2003). "Gender-Typical Responses to Sexual and Emotional Infidelity as a Function of Mortality Salience Induced Self-Esteem Striving". Personality and Social Psychology Bulletin. 29 (12): 1585–1595. doi:10.1177/0146167203256880. PMID 15018688. S2CID 19133225.
^ Sheppard, V. J.; Nelso, E. S.; Andreoli-Mathie, V. (1995). "Dating relationships and infidelity: Attitudes and behaviors". Journal of Sex & Marital Therapy. 21 (3): 202–212. doi:10.1080/00926239508404399. PMID 7500371.
^ Roscoe, B.; Cavanaugh, L. E.; Kennedy, D. R. (1988). "Dating infidelity: Behaviors, reasons and consequences". Adolescence. 23 (89): 35–43. PMID 3381685.
^ Glass, S. P.; Wright, T. L. (1992). "Justifications for extramarital relationships: The association between attitudes, behaviors, and gender". Journal of Sex Research. 29 (3): 361–387. doi:10.1080/00224499209551654.
^ Atkins, DC; Baucom, DH; Jacobson, NS (December 2001). "Understanding infidelity: correlates in a national random sample". J Fam Psychol. 15 (4): 735–49. doi:10.1037/0893-3200.15.4.735. PMID 11770478. S2CID 20925417.
^ Feldman, S. S.; Cauffman, E. (1999). "Your cheatin' heart: Attitudes, behaviors, and correlates of sexual betrayal in late adolescents". Journal of Research on Adolescence. 9 (3): 227–252. doi:10.1207/s15327795jra0903_1.
^ Adultery by Louise DeSalvo.
^ Kathiya, Henna (1 April 2010). "Adultery has roots in psychology, biology". The Daily Targum. Rutgers University. Archived from the original on August 21, 2011. Retrieved 16 September 2011.
^ Hupka, Ralph B.; Buunk, Bram; Falus, Gábor; Fulgosi, Ante; Ortega, Elsa; Swain, Ronny; Tarabrina, Nadia (1985). "Romantic Jealousy and Romantic Envy: A Seven-Nation Study". Journal of Cross-Cultural Psychology. 16 (4): 423–46. doi:10.1177/0022002185016004002. S2CID 145376600.
^ Harris, Christine R.; Christenfeld, Nicholas (1996). "Jealousy and Rational Responses to Infidelity Across Gender and Culture". Psychological Science. 7 (6): 378–79. doi:10.1111/j.1467-9280.1996.tb00394.x. S2CID 36000699.
^ Geary, David C.; Rumsey, Michael; Bow-Thomas, Christine; Hoard, Mary K. (1995). "Sexual Jealousy as a Facultative Trait: Evidence from the Pattern of Sex Differences in Adults from China and the United States". Ethology and Sociobiology. 16 (5): 355–83. doi:10.1016/0162-3095(95)00057-7.
^ Burdette, Amy M.; Ellison, Christopher G.; Sherkat, Darren E.; Gore, Kurt A. (2007). "Are Their Religious Variations in Material Infidelity". Journal of Family Issues. 28 (12): 1553–581. doi:10.1177/0192513x07304269. S2CID 145714348.
^ Buss, David; Schmitt, David (1 May 1993). "Sexual Strategies Theory: An Evolutionary Perspective on Human Mating". Psychological Review. 100 (2): 204–32. doi:10.1037/0033-295X.100.2.204. PMID 8483982.
^ Hirsch, J. S.; Meneses, S.; Thompson, B.; Negroni, M.; Pelcastre, B.; RIo, C. (2007). "The inevitability of infidelity: Sexual reputation, social geographies, and marital HIV risk in rural Mexico". American Journal of Public Health. 97 (6): 986–996. doi:10.2105/ajph.2006.088492. PMC 1874214. PMID 17463368.
^ Meston, Cindy; Buss, David (2009). Why Women Have Sex: Understanding Sexual Motivations from Adventure to Revenge. Macmillan. p. 94.
^ Petersen, J. L.; Hyde, J. S. (2011). "Gender differences in sexual attitudes and behaviors: A review of meta-analytic results and large datasets". Journal of Sex Research. 48 (2–3): 149–165. doi:10.1080/00224499.2011.551851. PMID 21409712. S2CID 205442621.
^ Trivers, Robert (1972). Parental Investment and Sexual Selection (PDF). Vol. 136. Biological Laboratories, Harvard University Cambridge, MA.
^ Buss, D. M.; Haselton, M. (2005). "The Evolution of Jealousy". Trends in Cognitive Sciences. 9 (11): 506–507. doi:10.1016/j.tics.2005.09.006. PMID 16199197. S2CID 1650403.
^ Harris, C. R. (2000). "Psychophysiological responses to imagined infidelity: The specific innate modular view of jealousy reconsidered". Journal of Personality and Social Psychology. 78 (6): 1082–1091. doi:10.1037/0022-3514.78.6.1082. PMID 10870910. S2CID 18180981.
^ Buss, D. M. (1996). "Paternity uncertainty and the complex repertoire of human mating strategies". American Psychologist. 51 (2): 161–162. doi:10.1037/0003-066x.51.2.161.
^ Harris, C. R. (2005). "Male and female jealousy, still more similar than different: Reply to Sagarin (2005)". Personality and Social Psychology Review. 9 (1): 76–86. doi:10.1207/s15327957pspr0901_6. S2CID 35530393.
^ Harris, C. R. (2004). "The Evolution of Jealousy". American Scientist. 92 (1): 62–71. doi:10.1511/2004.45.919.
^ Cramer, R. E.; Lipinski, R. E.; Meeter, J. D.; Houska, J. A. (2008). "Sex Differences in Subjective Distress to Unfaithfulness: Testing Competing Evolutionary and Violation of Infidelity Expectations Hypotheses". Journal of Social Psychology. 148 (4): 389–405. doi:10.3200/socp.148.4.389-406. PMID 18807418. S2CID 17843905.
^ Fisher, M.; Geher, G.; Cox, A.; Tran, U.S.; Hoben, A.; Arrabaca, A.; Chaize, C.; Deitrich, R.; Voracek, M. (2009). "Impact of Relational Proximity on Distress from Infidelity". Evolutionary Psychology. 7 (4): 560–580. doi:10.1177/147470490900700406.
^ Scheuring, I. (2010). "Coevolution of honest signaling and cooperative norms by cultural group selection". Biosystems. 101 (2): 79–87. Bibcode:2010BiSys.101...79S. doi:10.1016/j.biosystems.2010.04.009. PMID 20444429.
^ Fisher et al., 2010
^ Young, K. S.; Griffin-Shelley, E.; Cooper, A.; O'mara, J.; Buchanan, J. (2000). "Online infidelity: A new dimension in couple relationships with implications for evaluation and treatment". Sexual Addiction & Compulsivity: The Journal of Treatment and Prevention. 7 (1–2): 59–74. doi:10.1080/10720160008400207. S2CID 143786655.
^ Whitty, Monica (January 2004). "Cybercheating: What do people perceive to be infedelity [sic] in online relationships?". Counselling and Psychotherapy Journal.
^ Randall, H.E.; Byers, E (1 January 2003). "What is sex? Students' definitions of having sex, sexual partner, and unfaithful sexual behaviour". Canadian Journal of Human Sexuality. 12: 87–96.
^ Daneback, K.; Al Cooper, Ph; Månsson, S. (2005). "An Internet study of cybersex participants". Archives of Sexual Behavior. 34 (3): 321–328. doi:10.1007/s10508-005-3120-z. PMID 15971014. S2CID 2435329.
^ Cooper, A.; Morahan-Martin, J.; Mathy, R. M.; Maheu, M. (2002). "Toward an increased understanding of user demographics in online sexual activity". Journal of Sex & Marital Therapy. 28 (2): 105–129. doi:10.1080/00926230252851861. PMID 11894795. S2CID 22245574.
^ Groothof, Hinke A. K.; Dijkstra, Pieternel; Barelds, Dick P. H. (December 2009). "Sex differences in jealousy: The case of Internet infidelity". Journal of Social and Personal Relationships. 26 (8): 1119–1129. doi:10.1177/0265407509348003. S2CID 52087028.
^ Whitty, Monica T. (February 2005). "The Realness of Cybercheating: Men's and Women's Representations of Unfaithful Internet Relationships" (PDF). Social Science Computer Review. 23 (1): 57–67. doi:10.1177/0894439304271536. S2CID 59023323.
^ Mathiak, K.; Weber, R. (2006). "Toward brain correlates of natural behavior:fMRI during violent video games". Human Brain Mapping. 27 (12): 948–956. doi:10.1002/hbm.20234. PMC 6871426. PMID 16628606.
^ Parks, M.R.; Floyd, K. (1996). "Making friends in cyberspace". Journal of Communication. 46: 80–97. doi:10.1111/j.1460-2466.1996.tb01462.x.
^ Parks, M.R.; Roberts, L.D. (1998). "'Making MOOsic': The development of personal relationships on line and a comparison to their off-line counterparts". Journal of Social and Personal Relationships. 15 (4): 517–537. doi:10.1177/0265407598154005. S2CID 145209206.
^ Whitty, M.; Gavin, J. (2001). "Age/Sex/Location: Uncovering the Social Cues in the Development of Online Relationships". Cyberpsychology & Behavior. 4 (5): 623–630. doi:10.1089/109493101753235223. hdl:2381/9609. PMID 11725656. S2CID 637814.
^ Schneider, J. P. (2003). "The impact of compulsive cybersex behaviours on the family". Sexual & Relationship Therapy. 18 (3): 329–354. doi:10.1080/146819903100153946. S2CID 145414867.
^ Online Infidelity in Internet Chat Rooms: An Ethnographic Exploration
^ Drash, Wayne (2009-12-08). "Beware cheaters: Your lover's spouse can sue you". CNN. Retrieved 2015-02-26.
^ Gomstyn, Alice (23 March 2010). "Wife Wins $9 Million From Husband's Alleged Mistress". ABC News.
^ "Woman wins 'alienation of affection' case". UPI.
^ "Crimes Against Marriage". The Maryland People's Law Library.
^ "Adultery laws: where is cheating still illegal?". The Week UK.
^ Nicolas, Peter (8 February 2013). "The Lavender Letter: Applying the Law of Adultery to Same Sex Couples and Same Sex Conduct". Florida Law Review. 63 (1): 97.
^ "Recommendation Rec(2002)5 of the Committee of Ministers to member States on the protection of women against violence" (PDF). Council of Europe. 2002.
^ "Decriminalization of adultery and defenses". UN Women.
^ Kuroki, Masanori (January 2013). "Opposite-sex coworkers and marital infidelity". Economics Letters. 118 (1): 71–73. doi:10.1016/j.econlet.2012.09.023.
^ Losee, Stephanie; Olen, Helaine (2007). Office Mate: The Employee Handbook for Finding—and Managing—Romance on the Job. Avon, Mass.: Adams Media. ISBN 978-1-59869-330-0. OCLC 502925213.
^ Stoller, Gary (2007-04-23). "Infidelity is in the air for road warriors". USA Today. Retrieved 2009-10-19.
^ Ali, Lorraine (8 August 2004). "Marriage: The New Infidelity". Newsweek.
^ Laino, Debra. "Why Women Cheat". ShaveMagazine.com. Archived from the original on 2010-02-04. Retrieved 2010-02-10.
^ Hyde, Byers & DeLamater 2009, p. .
^ Jenks, R. J. (1998). "Swinging: A review of the literature". Archives of Sexual Behavior. 27 (5): 507–521. doi:10.1023/a:1018708730945. PMID 9795730. S2CID 5971960.
^ Henshel, Anne-Marie (January 1973). "Swinging: A Study of Decision Making in Marriage". American Journal of Sociology. 78 (4): 885–891. doi:10.1086/225408. JSTOR 2776609. S2CID 143595796.
^ Ritchie, A.; Barker, M. (2006). "'There Aren't words for what we do or how we feel so we have to make them up': Constructing polyamorous languages in a culture of compulsory monogamy" (PDF). Sexualities. 9 (5): 584–601. doi:10.1177/1363460706069987. S2CID 56365641. | biology | 846423 | https://no.wikipedia.org/wiki/Hemmet%20seksuell%20opphisselse%20hos%20kvinner | Hemmet seksuell opphisselse hos kvinner | Hemmet seksuell opphisselse hos kvinner (FSAD), ofte referert til som frigiditet , er en lidelse preget av en vedvarende eller gjentatt manglende evne til å oppnå seksuell opphisselse eller å opprettholde opphisselse til fullføringen av en seksuell aktivitet eller en tilstrekkelig lubrikasjon – fuktighets-oppsvulmings-reaksjon som ellers er stede under opphisselse og seksuell aktivitet. Tilstanden bør skilles fra et generelt tap av interesse for seksuell aktivitet og fra andre seksuell dysfunksjoner, slik som kvinnelig orgasmeforstyrrelse (anorgasmi) og hypoaktiv seksuell dysfunksjon (manglende lyst) som karakteriseres som mangel eller fravær på seksuelle fantasier og begjær for seksuell aktivitet over en viss periode.
Selv om kvinnelig seksuell dysfunksjon for tiden er en omdiskutert diagnose, begynner farmasøytiske selskaper å markedsføre produkter til behandling av hypoaktiv seksuell dysfunksjon (lystforstyrrelse) ofte med lave doser av testosteron.
Inndeling
Det finnes flere inndelinger på nedsatt seksuell respons hos kvinner. Disse kan indikere utbruddet: primær (livslang) eller sekundær (ervervet). De kan være basert på kontekst: det kan være i enhver sammenheng (generalisert) eller situasjonsbetinget. For eksempel kan problemet være tilstede med en ektefelle, mens det ikke er noe problem med en annen partner.
Hvor lenge tilstanden har vart, og i hvilken grad den er partner- eller situasjonsspesifikk, kan være et resultat av ulike årsaksfaktorer og kan påvirke behandlingen for tilstanden. Det kan skyldes psykologiske faktorer eller en kombinasjon av faktorer.
Diagnostiske trekk
I DSM-IV (American Psychiatric Association 1994) er diagnostiske kriterier for kvinnelig seksuell opphisselse lidelser:
Vedvarende eller tilbakevendende sviktende evne til å oppnå tilstrekkelig lubrikasjon (fuktighets-oppsvulmingsreaksjon på seksuell opphisselse) til gjennomføring av seksuell aktivitet.
Forstyrrelsen forårsaker merkbart ubehag eller mellommenneskelige problemer
Den seksuelle dysfunksjon beskrives ikke bedre av en annen Akse I-lidelse (utenom andre seksuelle dysfunksjoner) og skyldes ikke utelukkende de direkte fysiologiske virkninger av en substans (for eksempel legemiddel eller stoffmisbruk) eller en underliggende medisinsk tilstand.
Marita P. McCabe har merket seg at
"Problemer oppstår med denne definisjonen i forhold til hva som utgjør tilstrekkelig lubrikasjon. Det finnes ingen "gullstandard" på hvor lang tid det skal ta å bli opphisset eller på grad av opphisselse som skal oppnås. Disse responsene kan variere fra kvinne til kvinne og er avhengig av en rekke faktorer, inkludert humøret generelt når seksuell stimulering begynner og partners ferdigheter i å stimulere henne. Det kan også være forskjeller mellom fysiologisk og subjektiv grad av opphisselse. Noen kvinner sier de ikke føler seg seksuelt opphisselse tross økt fysiologisk respons som blodgjennomstrømning i skjedeveggen, mens andre sier de opplever seg seksuelt opphisset uten at det er påvisbar fysiologisk respons. Forventninger og tidligere erfaringer hos klinikere og klienter kan også lede dem til å klassifisere samme symptomene som sviktende seksuell respons hos en kvinne, men ikke hos en annen. "
Årsaker
En rekke studier har undersøkt hvilke faktorer som bidrar til hemmet seksuell respons og orgasmeforstyrrelse hos kvinner. Det omfatter både psykologiske og fysiske faktorer. Psykologisk sett kan følger av erfaringer fra barndom- og oppvekst, samt aktuelle hendelser – både hos kvinnen selv og i den aktuelle parrelasjonen være mulige årsaker til problemet.
Følger av hendelser i barndoms- og ungdomstiden
De fleste studier som har vurdert følgene av opplevelser i oppveksten på kvinnelig seksuell dysfunksjon blir vurdert som potensielt metodisk svake. Studiene stoler på retrospektiv hukommelse, noe som er spesielt problematisk når følelsesmessige reaksjoner på hendelsen blir rapportert så vel som den faktiske hendelsen . Det ser imidlertid ut til å være koblinger mellom seksuelle overgrep i barndommen og senere seksuelle problemer.
Enkeltfaktorer hos kvinnen
Det har vært lite undersøkelser av følgen av enkeltfaktorer på kvinnelig seksuell dysfunksjon. Slike faktorer er stress, tretthetsgrad, kjønnsidentitet, helse og andre individuelle egenskaper og erfaringer som kan påvirke seksuell lyst eller respons. Overeksponering for pornografilignende media antas å føre til dårlig kroppsbilde, selvbilde og nedsatt selvfølelse. En enkeltpersons seksuelle aktivitet kan forstyrres av overveldende følelsesmessig ubehag som resulterer i manglende evne til å oppnå seksuell nytelse.
Faktorer i parforholdet
En betydelig mengde vitenskapelige studier har utforsket rollen mellommenneskelige faktorer spiller på kvinnelig seksuell dysfunksjon, spesielt i forhold til orgasmerespons. Disse studiene har i stor grad fokusert på følger av kvaliteten på forholdet når det gjelder den seksuelle funksjonen til partnerne. Noen studier har vurdert betydningen av spesifikke relasjonsvariabler, mens andre har undersøkt generell tilfredshet i forholdet. Noen studier har utforsket hendelser, mens andre har fokusert på holdninger som et empirisk mål på hvordan forholdet fungerer. Populasjoner som har blitt undersøkt har variert fra ulykkelige par og seksuelt dysfunksjonelle klienter til par med høy grad av tilfredshet i forholdet.
Fysiske faktorer
Anslag over andelen kvinnelig seksuell dysfunksjon som kan tilskrives fysiske faktorer har variert fra 30 % til 80 %. Lidelsene som med størst sannsynlighet kan føre til seksuell dysfunksjon er de som fører til forstyrrelser i kar- eller nervefunksjon. Disse faktorene har blitt mer omfattende undersøkt blant menn enn hos kvinner. Fysiske årsaker som for eksempel nevrologiske og hjerte- og karsykdommer har vært direkte innblandet i både tidlig og forsinket utløsning, samt erektil dysfunksjon (Hawton 1993), men bidraget av fysiologiske faktorer til kvinnelig seksuelle dysfunksjoner er ikke like tydelig. Men nyere litteratur tyder på at det kan være en svekkelse i opphisselsesfasen hos kvinner med diabetes. Gitt at kvinner med diabetes viser en betydelig variasjon i sine svar på denne medisinske lidelsen, er det ikke overraskende at sykdommens påvirkning av opphisselse også er svært variabel. Faktisk tyder mangelen på en klar sammenheng mellom medisinske lidelser og seksuell funksjon på at psykologiske faktorer spiller en betydelig rolle i virkningen av disse lidelsene på seksuell funksjon (Melman et al. 1988).
Kenneth Maravilla, professor i radiologi og nevrologisk kirurgi og direktør for MR Research Laboratory ved University of Washington, Seattle, presenterte forskningsresultater basert på bildediagnostikk av kvinners seksuelle funksjon. I en liten pilotstudie på fire kvinner med hemmet seksuell opphisselse, rapporterte Maravilla at det var mindre hjerneaktivisering sett i denne gruppen, blant annet svært lite aktivering i amygdala. Disse kvinnene viste også økt aktivering i temporale områder, i motsetning til kvinner uten seksuelle problemer som viste deaktivering i lignende områder. Dette kan tyde på økt grad av hemming ved opphisselsesstimuli hos denne lille gruppen av kvinner med FSAD.
Behandling
Selv om det er stor variasjon i hvordan sviktende seksuell respons og orgasmeforstyrrelser uttrykkes hos kvinner, er det ingen dokumentasjon som tyder på at forskjellige faktorer bidrar til de to tilstandene, eller at ulike behandlingsstrategier bør brukes. Faktisk anvendes generelt de samme behandlingsstrategiene for begge tilstandene. Disse strategiene må kanskje suppleres med ekstra teknikker for å løse spesifikke problemer for enkelte kvinner, men de er generelt gode utgangspunkter for å løse problemene som bidrar til utvikling og vedlikehold av det seksuelle problemet. Fordi forholdet mellom kvinnen og hennes partner har vist seg å spille en betydelig rolle i både utvikling og vedlikehold av seksuelle problemer, er de fleste programmer laget slik at de skal gjennomføres av paret. Det finnes imidlertid også andre strategier som fokuserer på individet. Det er også viktig å skille tilstanden fra manglende seksuell lyst.
Kritiske bemerkninger
Begrepet hemmet seksuell respons hos kvinner er ikke uten kritiske bemerkninger.
Kilder
Female Sexual Arousal Disorder and Female Orgasmic Disorder''Se også
Hemmet seksuell opphisselse
Seksuell dysfunksjon
Seksuell funksjon
Anorgasmi
Referanser
Anbefalt lesing
Barlow David H (1986): The causes of sexual dysfunction: the role of anxiety and cognitive interference. Journal of Consulting and Clinical Psychology, 54, 140-148
Beck J Gayle og Barlow David H (1984): Current conceptualizations of sexual dysfunction: a review and an alternative perspective.'' Clinical Psychology Review, 9, 37-47.
Cahill C, Llewelyn SP, Pearson C: Long term effects of sexual abuse which occurred in childhood: a review. Br J Clin psychol 30:117-130, 1991
Delaney SM, McCabe MP: Secondary inorgasmia in women: a treatment program and case study. Sexual and Marital Therapy 3:165-190, 1988
Hallström T, Samuelsson S: Changes in women's sexual desire in middle life: the longitudinal study of women in Gothenburg. Arch Sex Behav 19:259-268, 1990
Hawton K: Sex Therapy. Oxford, UK, Oxford University Press, 1993
Heiman JR, Gladue BA, Roberts CW, et al:. Historical and current factors discriminating sexually functional from sexually dysfunctional married couples. J Marital Fam Ther 12:163-174, 1986
Hoch Z, Safir MP, Peres G, et al: An evaluation of sexual performance – comparison between sexually dysfunctional and functional couples. J Sex Marital Ther 7:195-206, 1981
The sexual genogram. J Marital Fam Ther 12:39-47, 1986
Hulbert DF. The role of assertiveness in female sexuality: a comparative study between sexually assertive and sexually non-assertive women. J Sex Marital Ther 17:183-190, 1991
Kilpatrick AC. Some correlates of women's childhood sexual experiences: a retrospective study. J Sex Res 22:221-242, 1986
Salamonsen LA: Hormonal activity in the endometrium: tissue remodelling and uterine bleeding, in Progress in the Management of Menopause. Redigert av Wren BG. London, Parthenon, 1997, pp 212–216
Laks UJ, Geist SH: The effects of androgens upon libido in women. Journal of Clinical Endocrinology 3:235-238, 1943
Segraves RT, Segraves KB. Human sexuality and aging. Journal of Sex Education and Therapy 21:88-102, 1995
Spector IP, Carey P: Incidence and prevalence of the sexual dysfunctions: a critical review of the empirical literature. Arch Sex Behav 19:389-408, 1990
Spector KR, Boyle M: The prevalence and perceived aetiology of male sexual problems in a non-clinical sample. Br J Med psychol 59:351-358, 1986
Eksterne lenker
Helsebibliotekets sider for kjønn og seksualitet
Nedsatt seksuell tenning hos kvinner på Norsk Helseinformatikk AS
Kvinnelig seksuell dysfunksjon i oppslagsverket BMJ Best Practice
Sexual Problems Overview Seksuelle problemer hos kvinner i Emedicine
Useful Addresses – The Sexual Dysfunction Association
A brief review that explores issues of the medicalization of the female orgasm
Our Bodies Ourselves chapter on Female Sexual Dysfunction: A Feminist View
Det kvinnelige reproduktive system
Seksuelle dysfunksjoner og kjønnsidentitetsforstyrrelser
Seksuell helse
Seksuell opphisselse
Kvinnehelse | norwegian_bokmål | 0.603964 |
human_monogamy/human-being.txt |
Home Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos On This Day One Good Fact Dictionary New Articles History & Society Lifestyles & Social Issues Philosophy & Religion Politics, Law & Government World History Science & Tech Health & Medicine Science Technology Biographies Browse Biographies Animals & Nature Birds, Reptiles & Other Vertebrates Bugs, Mollusks & Other Invertebrates Environment Fossils & Geologic Time Mammals Plants Geography & Travel Geography & Travel Arts & Culture Entertainment & Pop Culture Literature Sports & Recreation Visual Arts Companions Demystified Image Galleries Infographics Lists Podcasts Spotlights Summaries The Forum Top Questions #WTFact 100 Women Britannica Kids Saving Earth Space Next 50 Student Center
Home Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos On This Day One Good Fact Dictionary New Articles History & Society Lifestyles & Social Issues Philosophy & Religion Politics, Law & Government World History Science & Tech Health & Medicine Science Technology Biographies Browse Biographies Animals & Nature Birds, Reptiles & Other Vertebrates Bugs, Mollusks & Other Invertebrates Environment Fossils & Geologic Time Mammals Plants Geography & Travel Geography & Travel Arts & Culture Entertainment & Pop Culture Literature Sports & Recreation Visual Arts Companions Demystified Image Galleries Infographics Lists Podcasts Spotlights Summaries The Forum Top Questions #WTFact 100 Women Britannica Kids Saving Earth Space Next 50 Student Center
Home Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos
Home Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos
Home Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos
Home Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture Money Videos
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare
human being Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare
Table of Contents Introduction References & Edit History Quick Facts & Related Topics Images & Videos Quizzes Know Your Mammals Quiz Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work? Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare
Related Questions What is Charles Darwin famous for? What is evolution, as Charles Darwin understood it? What was Charles Darwin’s educational background? What was Charles Darwin’s family life like? What were the social impacts of Charles Darwin’s work?
Read Next 9 of the World’s Deadliest Mammals The Oldest Human Ancestor The Anthropocene Epoch: Adding Humans to the Chart of Geologic Time What Darwin Got Right (and Wrong) About Evolution
Discover A Timeline of Environmental History Timeline of the Titanic ’s Final Hours Can Apple Seeds Kill You? Inventors and Inventions of the Industrial Revolution Vietnam War Timeline Where Is the Ark of the Covenant? The Death of Shakespeare
Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
Contents Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
Home Lifestyles & Social Issues Sociology & Society human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History Table of Contents Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals? Also known as: human, human race, man, mankind Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History
human being Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
Actions Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Give Feedback External Websites
Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation
verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation
verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.
Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other
Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.
External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
Print Cite verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation Share Share Share to social media Facebook Twitter URL https://www.britannica.com/topic/human-being Feedback External Websites Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article. External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation
verified Cite While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions. Select Citation Style MLA APA Chicago Manual of Style Copy Citation
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.
Feedback Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login). Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other Your Feedback Submit Feedback Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Feedback Type Select a type (Required) Factual Correction Spelling/Grammar Correction Link Correction Additional Information Other
Thank you for your feedback Our editors will review what you’ve submitted and determine whether to revise the article.
External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
External Websites Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
Smithsonian National Museum of Natural History - Human Characteristics: What Does it Mean to be Human National Library of Medicine - What a human being is Cleveland Clinic - Genetic Mutations in Humans Princeton University - When Do Human Beings Begin? Arizona State University - Ask A Biologist - How are humans different from other animals?
Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica Last Updated: Apr 26, 2024 • Article History
Written and fact-checked by The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors. The Editors of Encyclopaedia Britannica
The Editors of Encyclopaedia Britannica Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.
Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.
Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content → Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US? Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans. (Read Yuval Noah Harari’s Britannica essay on the future of “Nonconscious Man.”) Britannica Quiz Know Your Mammals Quiz Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution . (Read Ray Kurzweil’s Britannica essay on the future of “Nonbiological Man.”) The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . This article was most recently revised and updated by John P. Rafferty .
Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more) See all related content →
Key People: Hwang Woo-Suk Severino Antinori Moon Shin Yong Herophilus Elman Rogers Service (Show more) Related Topics: anthropology race philosophical anthropology human evolution person (Show more)
Recent News Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US?
Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US?
Apr. 24, 2024, 6:47 AM ET (ABC News (Australia)) Voyager 1 talking to Earth again after NASA engineers 24 billion kilometres away devise software fix
Apr. 7, 2024, 5:23 AM ET (Straits Times) What do scientists hope to learn from total solar eclipse in US?
Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article
Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article
Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article
Hear a discussion about the uniqueness in humans which separates them from other animals What is it to be human? (more) See all videos for this article
Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species Psycholinguist Steven Pinker outlining uniquely human traits. (more) See all videos for this article
Hear psycholinguist Steven Pinker outlining the evolution of several unique traits in humans as compared with other species
Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species Learn about early species in the genus Homo and scholarly debates over what defines being human. (more) See all videos for this article
Compare Homo habilis , H. erectus , H. neanderthalensis , and H. sapiens to determine the first human species
human being , a culture-bearing primate classified in the genus Homo , especially the species H. sapiens . Human beings are anatomically similar and related to the great apes but are distinguished by a more highly developed brain and a resultant capacity for articulate speech and abstract reasoning . In addition, human beings display a marked erectness of body carriage that frees the hands for use as manipulative members. Some of these characteristics, however, are not entirely unique to humans. The gap in cognition , as in anatomy, between humans and the great apes ( orangutans , gorillas , chimpanzees , and bonobos ) is much less than was once thought, as they have been shown to possess a variety of advanced cognitive abilities formerly believed to be restricted to humans.
Traditionally, humans were considered the sole recent representatives of the family Hominidae , but recent findings indicate that chimpanzees and bonobos are more closely related to humans than are gorillas and orangutans and that the last common ancestor between the chimpanzee and human lines lived sometime between seven million and six million years ago. Therefore, all great apes are now gathered with humans into Hominidae, and within that family humans and their extinct ancestors are considered to make up the tribe Hominini . See also Homo sapiens ; human evolution .
The term man has traditionally referred to humans in general, or humankind. The idea of man is treated in a number of articles. For a philosophical treatment of the subject, see philosophical anthropology . For the physical anthropology of human ancestry, see human evolution . For an examination of human culture , see art ; cuisine ; dance ; government ; literature ; music ; sport . For other related articles, see collective behaviour ; death ; emotion ; family ; human behaviour ; human rights ; intelligence ; kinship ; language ; learning theory ; mind, philosophy of ; motivation ; perception ; personality ; population ; sexual behaviour, human ; social structure ; Stone Age ; technology ; thought . | biology | 929254 | https://sv.wikipedia.org/wiki/Sociobiologi | Sociobiologi | Sociobiologi eller socialbiologi är en evolutionärt inriktad syntes av vetenskapliga discipliner som försöker förklara socialt beteende inom alla arter genom att undersöka de evolutionära fördelar som beteendet kan ge. Det betraktas ofta som en gren av biologi och sociologi, och drar således även insikter från etologi, antropologi, evolution, zoologi, arkeologi, populationsgenetik och andra discipliner. Inom studiet av mänskliga samhällen är sociobiologi nära relaterat till humanekologi och evolutionspsykologi. Under senare tid har begreppet sociobiologi mer eller mindre övergått till evolutionspsykologi.
Sociobiologin studerar djurens beteende (inklusive människans), vilka evolutionära fördelar olika beteenden har och vilken selektion som gör att dessa beteenden sprider sig. Sociobiologin introducerades via en inflytelserik bok av biologen E. O. Wilson år 1975. Generellt hävdar företrädarna att det finns en genetisk bakgrund till många beteenden. Begreppet släktskapsselektion introducerades på bred front av företrädarna för denna skola.
Kända sociobiologer
Pierre van den Berghe
Richard Dawkins
Daniel Dennett
Edward O. Wilson
W. D. Hamilton
J. P. Rushton
George C. Williams
John Maynard Smith
Sarah Blaffer Hrdy
Richard Machalek
Steven Pinker
Kritik
Kritiken mot sociobiologin riktar sig främst in på att peka på kopplingen mellan sociobiologi och biologisk determinism; att olikheter mellan människor beror på specifika genetiska orsaker snarare än skillnader sprungna ur kulturella och sociala miljöer. Kritikerna menar att den biologiska determinismen var en grundläggande ideologisk och filosofisk förutsättning för socialdarwinismen, de rashygienrörelser som verkade under 1900-talet, samt kontroverser runt intelligenstester.
Se även
Evolution
Psykologi
Evolutionspsykologi
Humanekologi
Kulturell evolution
Socialt beteende
Vidare läsning
Sociobiology: The New Synthesis av E. O. Wilson, 1975
Ett oskrivet blad av Steven Pinker
Den själviska genen (The Selfish Gene) av Richard Dawkins
Biology, Ideology and Human Nature: Not In Our Genes av Richard Lewontin, Steven Rose & Leon Kamin
Alcock, John (2001). The Triumph of Sociobiology. Oxford: Oxford University Press.
Barkow, Jerome (Ed.). (2006) Missing the Revolution: Darwinism for Social Scientists. Oxford: Oxford University Press.
Cronin, H. (1992). The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today. Cambridge: Cambridge University Press.
Richards, Janet Radcliffe (2000). Human Nature After Darwin: A Philosophical Introduction. London: Routledge.
Referenser
Externa länkar
Sociobiology (Stanford Encyclopedia of Philosophy) - Harmon Holcomb & Jason Byron
Speak, Darwinists! Intervjuer med ledande sociobiologer.
Race and Creation - Richard Dawkins
Genetic Similarity and Ethnic Nationalism - Ett försök till förklaring av politisk gruppformering från sociobiologiskt perspektiv
En kort historia över sociobiologin - New York Times
Evolution
Sociologi
Biologi | swedish | 0.573603 |
human_monogamy/Human_behavior.txt |
Main menu Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file Search Search Create account Log in Personal tools Create account Log in Pages for logged out editors learn more Contributions Talk
Main menu Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Main menu Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Search Search Create account Log in Personal tools Create account Log in Pages for logged out editors learn more Contributions Talk
Contents move to sidebar hide (Top) 1 Study 2 Social behavior Toggle Social behavior subsection 2.1 Social norms 2.2 Interpersonal relationships 2.3 Politics and conflict 3 Cognitive behavior 4 Physiological behavior 5 Economic behavior Toggle Economic behavior subsection 5.1 Work 5.2 Leisure 5.3 Consumption 6 Ecological behavior 7 Causes and factors Toggle Causes and factors subsection 7.1 Age 7.2 Culture and environment 7.3 Genetics 7.4 Physiology 8 See also 9 References 10 Bibliography 11 Further reading 12 External links Toggle the table of contents Human behavior 22 languages العربية বাংলা Català Deutsch Español Esperanto فارسی Français 한국어 Հայերեն हिन्दी Bahasa Indonesia עברית Қазақша Kiswahili Bahasa Melayu Slovenčina Suomi Українська اردو 粵語 中文 Edit links Article Talk English Read Edit View history Tools Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote From Wikipedia, the free encyclopedia Array of every physical action and observable emotion associated with humans For the song, see Human Behaviour . Social interaction and creative expression are forms of human behavior Part of a series on Sociology History Outline Index Key themes Society Globalization Human behavior Human environmental impact Identity Industrial revolutions 3 / 4 / 5 Social complexity Social construct Social environment Social equality Social equity Social power Social stratification Social structure Perspectives Conflict theory Critical theory Structural functionalism Positivism Social constructionism Symbolic interactionism Branches Aging Architecture Art Astrosociology Body Criminology Consciousness Culture Death Demography Deviance Disaster Economic Education Emotion ( Jealousy ) Environmental Family Feminist Fiscal Food Gender Generations Health Historical Immigration Industrial Internet Jewry Knowledge Language Law Leisure Literature Marxist Mathematic Medical Military Music Peace, war, and social conflict Philosophy Political Public Punishment Race and ethnicity Religion Rural Science ( History of science ) Social movements Social psychology Sociocybernetics Sociology Space Sport Technology Terrorism Urban Utopian Victimology Visual Methods Quantitative Qualitative Comparative Computational Ethnographic Conversation analysis Historical Interview Mathematical Network analysis Social experiment Survey Sociologists 1700s: Comte · Sieyès 1800s: Martineau · Tocqueville · Marx · Spencer · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Marcuse 1900s: Fromm · Adorno · Merton · Mills · Goffman · Bauman · Foucault · Habermas · Baudrillard · Bourdieu · Giddens Lists Bibliography Terminology Journals Organizations People Timeline By country Society portal v t e Human behavior is the potential and expressed capacity ( mentally , physically , and socially ) of human individuals or groups to respond to internal and external stimuli throughout their life. Behavior is driven by genetic and environmental factors that affect an individual. Behavior is also driven, in part, by thoughts and feelings , which provide insight into individual psyche , revealing such things as attitudes and values . Human behavior is shaped by psychological traits , as personality types vary from person to person, producing different actions and behavior. Social behavior accounts for actions directed at others. It is concerned with the considerable influence of social interaction and culture , as well as ethics , interpersonal relationships , politics , and conflict . Some behaviors are common while others are unusual. The acceptability of behavior depends upon social norms and is regulated by various means of social control . Social norms also condition behavior, whereby humans are pressured into following certain rules and displaying certain behaviors that are deemed acceptable or unacceptable depending on the given society or culture. Cognitive behavior accounts for actions of obtaining and using knowledge . It is concerned with how information is learned and passed on, as well as creative application of knowledge and personal beliefs such as religion . Physiological behavior accounts for actions to maintain the body. It is concerned with basic bodily functions as well as measures taken to maintain health. Economic behavior accounts for actions regarding the development, organization, and use of materials as well as other forms of work . Ecological behavior accounts for actions involving the ecosystem. It is concerned with how humans interact with other organisms and how the environment shapes human behavior. Study [ edit ] Main article: Human ethology Human behavior is studied by the social sciences , which include psychology , sociology , ethology , and their various branches and schools of thought. There are many different facets of human behavior, and no one definition or field study encompasses it in its entirety. The nature versus nurture debate is one of the fundamental divisions in the study of human behavior; this debate considers whether behavior is predominantly affected by genetic or environmental factors. The study of human behavior sometimes receives public attention due to its intersection with cultural issues, including crime , sexuality , and social inequality . Some natural sciences also place emphasis on human behavior. Neurology and evolutionary biology , study how behavior is controlled by the nervous system and how the human mind evolved , respectively. In other fields, human behavior may be a secondary subject of study when considering how it affects another subject. Outside of formal scientific inquiry, human behavior and the human condition is also a major focus of philosophy and literature . Philosophy of mind considers aspects such as free will , the mind–body problem , and malleability of human behavior. Human behavior may be evaluated through questionnaires , interviews , and experimental methods . Animal testing may also be used to test behaviors that can then be compared to human behavior. Twin studies are a common method by which human behavior is studied. Twins with identical genomes can be compared to isolate genetic and environmental factors in behavior. Lifestyle, susceptibility to disease, and unhealthy behaviors have been identified to have both genetic and environmental indicators through twin studies. Social behavior [ edit ] Further information: Sociology Women bowing in Japan ( c. 1880 ) Human social behavior is the behavior that considers other humans, including communication and cooperation. It is highly complex and structured, based on advanced theory of mind that allows humans to attribute thoughts and actions to one another. Through social behavior, humans have developed society and culture distinct from other animals. Human social behavior is governed by a combination of biological factors that affect all humans and cultural factors that change depending on upbringing and societal norms. Human communication is based heavily on language , typically through speech or writing . Nonverbal communication and paralanguage can modify the meaning of communications by demonstrating ideas and intent through physical and vocal behaviors. Social norms [ edit ] Human behavior in a society is governed by social norms . Social norms are unwritten expectations that members of society have for one another. These norms are ingrained in the particular culture that they emerge from, and humans often follow them unconsciously or without deliberation. These norms affect every aspect of life in human society, including decorum , social responsibility , property rights , contractual agreement , morality , justice , and meaning . Many norms facilitate coordination between members of society and prove mutually beneficial, such as norms regarding communication and agreements. Norms are enforced by social pressure , and individuals that violate social norms risk social exclusion . Systems of ethics are used to guide human behavior to determine what is moral. Humans are distinct from other animals in the use of ethical systems to determine behavior. Ethical behavior is human behavior that takes into consideration how actions will affect others and whether behaviors will be optimal for others. What constitutes ethical behavior is determined by the individual value judgments of the person and the collective social norms regarding right and wrong. Value judgments are intrinsic to people of all cultures, though the specific systems used to evaluate them may vary. These systems may be derived from divine law , natural law , civil authority , reason , or a combination of these and other principles. Altruism is an associated behavior in which humans consider the welfare of others equally or preferentially to their own. While other animals engage in biological altruism, ethical altruism is unique to humans. Deviance is behavior that violates social norms. As social norms vary between individuals and cultures, the nature and severity of a deviant act is subjective. What is considered deviant by a society may also change over time as new social norms are developed. Deviance is punished by other individuals through social stigma , censure , or violence . Many deviant actions are recognized as crimes and punished through a system of criminal justice . Deviant actions may be punished to prevent harm to others, to maintain a particular worldview and way of life, or to enforce principles of morality and decency . Cultures also attribute positive or negative value to certain physical traits, causing individuals that do not have desirable traits to be seen as deviant. Interpersonal relationships [ edit ] Main article: Interpersonal relationship A family in Noatak , Alaska (1929) Interpersonal relationships can be evaluated by the specific choices and emotions between two individuals, or they can be evaluated by the broader societal context of how such a relationship is expected to function. Relationships are developed through communication, which creates intimacy, expresses emotions, and develops identity. An individual's interpersonal relationships form a social group in which individuals all communicate and socialize with one another, and these social groups are connected by additional relationships. Human social behavior is affected not only by individual relationships, but also by how behaviors in one relationship may affect others. Individuals that actively seek out social interactions are extraverts , and those that do not are introverts. Romantic love is a significant interpersonal attraction toward another. Its nature varies by culture, but it is often contingent on gender, occurring in conjunction with sexual attraction and being either heterosexual or homosexual . It takes different forms and is associated with many individual emotions. Many cultures place a higher emphasis on romantic love than other forms of interpersonal attraction. Marriage is a union between two people, though whether it is associated with romantic love is dependent on the culture. Individuals that are closely related by consanguinity form a family . There are many variations on family structures that may include parents and children as well as stepchildren or extended relatives. Family units with children emphasize parenting , in which parents engage in a high level of parental investment to protect and instruct children as they develop over a period of time longer than that of most other mammals. Politics and conflict [ edit ] Further information: Political science , Theories of political behavior , and Conflict (process) A depiction of men fighting in the First Battle of Komárom (1849) When humans make decisions as a group, they engage in politics. Humans have evolved to engage in behaviors of self-interest , but this also includes behaviors that facilitate cooperation rather than conflict in collective settings. Individuals will often form in-group and out-group perceptions, through which individuals cooperate with the in-group and compete with the out-group. This causes behaviors such as unconsciously conforming, passively obeying authority, taking pleasure in the misfortune of opponents, initiating hostility toward out-group members, artificially creating out-groups when none exist, and punishing those that do not comply with the standards of the in-group. These behaviors lead to the creation of political systems that enforce in-group standards and norms. When humans oppose one another, it creates conflict. It may occur when the involved parties have a disagreement of opinion, when one party obstructs the goals of another, or when parties experience negative emotions such as anger toward one another. Conflicts purely of disagreement are often resolved through communication or negotiation , but incorporation of emotional or obstructive aspects can escalate conflict. Interpersonal conflict is that between specific individuals or groups of individuals. Social conflict is that between different social groups or demographics. This form of conflict often takes place when groups in society are marginalized, do not have the resources they desire, wish to instigate social change, or wish to resist social change. Significant social conflict can cause civil disorder . International conflict is that between nations or governments. It may be solved through diplomacy or war . Cognitive behavior [ edit ] Main article: Cognition People being taught to paint in Volgograd , Russia (2013) Human cognition is distinct from that of other animals. This is derived from biological traits of human cognition, but also from shared knowledge and development passed down culturally. Humans are able to learn from one another due to advanced theory of mind that allows knowledge to be obtained through education . The use of language allows humans to directly pass knowledge to one another. The human brain has neuroplasticity , allowing it to modify its features in response to new experiences. This facilitates learning in humans and leads to behaviors of practice , allowing the development of new skills in individual humans. Behavior carried out over time can be ingrained as a habit , where humans will continue to regularly engage in the behavior without consciously deciding to do so. Humans engage in reason to make inferences with a limited amount of information. Most human reasoning is done automatically without conscious effort on the part of the individual. Reasoning is carried out by making generalizations from past experiences and applying them to new circumstances. Learned knowledge is acquired to make more accurate inferences about the subject. Deductive reasoning infers conclusions that are true based on logical premises, while inductive reasoning infers what conclusions are likely to be true based on context. Emotion is a cognitive experience innate to humans. Basic emotions such as joy , distress , anger , fear , surprise , and disgust are common to all cultures, though social norms regarding the expression of emotion may vary. Other emotions come from higher cognition, such as love , guilt , shame , embarrassment , pride , envy , and jealousy . These emotions develop over time rather than instantly and are more strongly influenced by cultural factors. Emotions are influenced by sensory information , such as color and music , and moods of happiness and sadness . Humans typically maintain a standard level of happiness or sadness determined by health and social relationships, though positive and negative events have short-term influences on mood. Humans often seek to improve the moods of one another through consolation , entertainment , and venting . Humans can also self-regulate mood through exercise and meditation . Creativity is the use of previous ideas or resources to produce something original. It allows for innovation , adaptation to change, learning new information, and novel problem solving. Expression of creativity also supports quality of life . Creativity includes personal creativity, in which a person presents new ideas authentically , but it can also be expanded to social creativity, in which a community or society produces and recognizes ideas collectively. Creativity is applied in typical human life to solve problems as they occur. It also leads humans to carry out art and science . Individuals engaging in advanced creative work typically have specialized knowledge in that field, and humans draw on this knowledge to develop novel ideas. In art, creativity is used to develop new artistic works, such as visual art or music . In science, those with knowledge in a particular scientific field can use trial and error to develop theories that more accurately explain phenomena. Religious behavior is a set of traditions that are followed based on the teachings of a religious belief system. The nature of religious behavior varies depending on the specific religious traditions. Most religious traditions involve variations of telling myths , practicing rituals , making certain things taboo , adopting symbolism , determining morality, experiencing altered states of consciousness , and believing in supernatural beings. Religious behavior is often demanding and has high time, energy, and material costs, and it conflicts with rational choice models of human behavior, though it does provide community-related benefits. Anthropologists offer competing theories as to why humans adopted religious behavior. Religious behavior is heavily influenced by social factors, and group involvement is significant in the development of an individual's religious behavior. Social structures such as religious organizations or family units allow the sharing and coordination of religious behavior. These social connections reinforce the cognitive behaviors associated with religion, encouraging orthodoxy and commitment. According to a Pew Research Center report, 54% of adults around the world state that religion is very important in their lives as of 2018. Physiological behavior [ edit ] See also: Psychophysiology A boy eating in Harare , Zimbabwe (2017) Humans undergo many behaviors common to animals to support the processes of the human body . Humans eat food to obtain nutrition . These foods may be chosen for their nutritional value, but they may also be eaten for pleasure . Eating often follows a food preparation process to make it more enjoyable. Humans dispose of excess food through waste . Excrement is often treated as taboo, particularly in developed and urban communities where sanitation is more widely available and excrement has no value as fertilizer . Humans also regularly engage in sleep , based on homeostatic and circadian factors. The circadian rhythm causes humans to require sleep at a regular pattern and is typically calibrated to the day-night cycle and sleep-wake habits. Homeostasis is also be maintained, causing longer sleep longer after periods of sleep deprivation . The human sleep cycle takes place over 90 minutes, and it repeats 3–5 times during normal sleep. There are also unique behaviors that humans undergo to maintain physical health. Humans have developed medicine to prevent and treat illnesses. In industrialized nations, eating habits that favor better nutrition, hygienic behaviors that promote sanitation , medical treatment to eradicate diseases, and the use of birth control significantly improve human health. Humans can also engage in exercise beyond that required for survival to maintain health. Humans engage in hygiene to limit exposure to dirt and pathogens . Some of these behaviors are adaptive while others are learned. Basic behaviors of disgust evolved as an adaptation to prevent contact with sources of pathogens, resulting in a biological aversion to feces , body fluids , rotten food , and animals that are commonly disease vectors . Personal grooming , disposal of human corpses , use of sewerage , and use of cleaning agents are hygienic behaviors common to most human societies. Humans reproduce sexually , engaging in sexual intercourse for both reproduction and sexual pleasure . Human reproduction is closely associated with human sexuality and an instinctive desire to procreate , though humans are unique in that they intentionally control the number of offspring that they produce. Humans engage in a large variety of reproductive behaviors relative to other animals, with various mating structures that include forms of monogamy , polygyny , and polyandry . How humans engage in mating behavior is heavily influenced by cultural norms and customs. Unlike most mammals, human women ovulate spontaneously rather than seasonally, with a menstrual cycle that typically lasts 25–35 days. Humans are bipedal and move by walking . Human walking corresponds to the bipedal gait cycle , which involves alternating heel contact and toe off with the ground and slight elevation and rotation of the pelvis . Balance while walking learned during the first 7–9 years of life, and individual humans develop unique gaits while learning to displace weight, adjust center of mass , and correspond neural control with movement. Humans can achieve higher speed by running . The endurance running hypothesis proposes that humans can outpace most other animals over long distances through running, though human running causes a higher rate of energy exertion. The human body self-regulates through perspiration during periods of exertion, allowing humans more endurance than other animals. The human hand is prehensile and capable of grasping objects and applying force with control over the hand's dexterity and grip strength . This allows the use of complex tools by humans. Economic behavior [ edit ] Further information: Behavioral economics Humans engage in predictable behaviors when considering economic decisions, and these behaviors may or may not be rational . Like all animals, humans make basic decisions through cost–benefit analysis and the risk–return spectrum , though humans are able to contemplate these decisions more thoroughly. Human economic decision making is often reference dependent , in which options are weighed in reference to the status quo rather than absolute gains and losses. Humans are also loss averse , fearing loss rather than seeking gain. Advanced economic behavior developed in humans after the Neolithic Revolution and the development of agriculture . These developments led to a sustainable supply of resources that allowed specialization in more complex societies. Work [ edit ] Main article: Work (human activity) Women tending to farm animals in Mangskogs, Sweden (1911) The nature of human work is defined by the complexity of society. The simplest societies are tribes that work primarily for sustenance as hunter-gatherers . In this sense, work is not a distinct activity but a constant that makes up all parts of life, as all members of the society must work consistently to stay alive. More advanced societies developed after the Neolithic Revolution, emphasizing work in agricultural and pastoral settings. In these societies, production is increased, ending the need for constant work and allowing some individuals to specialize and work in areas outside of food-production. This also created non-laborious work, as increasing occupational complexity required some individuals to specialize in technical knowledge and administration. Laborious work in these societies has variously been carried out by slaves, serfs, peasants, and guild craftsmen. The nature of work changed significantly during the Industrial Revolution in which the factory system was developed for use by industrializing nations. In addition to further increasing general quality of life, this development changed the dynamic of work. Under the factory system, workers increasingly collaborate with others, employers serve as authority figures during work hours, and forced labor is largely eradicated. Further changes occur in post-industrial societies where technological advance makes industries obsolete, replacing them with mass production and service industries . Humans approach work differently based on both physical and personal attributes, and some work with more effectiveness and commitment than others. Some find work to contribute to personal fulfillment, while others work only out of necessity. Work can also serve as an identity, with individuals identifying themselves based on their occupation. Work motivation is complex, both contributing to and subtracting from various human needs. The primary motivation for work is for material gain, which takes the form of money in modern societies. It may also serve to create self-esteem and personal worth, provide activity, gain respect, and express creativity. Modern work is typically categorized as laborious or blue-collar work and non-laborious or white-collar work . Leisure [ edit ] Main article: Leisure Men playing association football in Kilkenny , Ireland (2007) Leisure is activity or lack of activity that takes place outside of work. It provides relaxation, entertainment , and improved quality of life for individuals. Engaging in leisure can be beneficial for physical and mental health. It may be used to seek temporary relief from psychological stress , to produce positive emotions, or to facilitate social interaction. Leisure can also facilitate health risks and negative emotions caused by boredom , substance abuse , or high-risk behavior . Leisure may be defined as serious or casual. Serious leisure behaviors involve non-professional pursuit of arts and sciences, the development of hobbies , or career volunteering in an area of expertise. Casual leisure behaviors provide short-term gratification, but they do not provide long-term gratification or personal identity. These include play , relaxation, casual social interaction, volunteering , passive entertainment, active entertainment, and sensory stimulation. Passive entertainment is typically derived from mass media , which may include written works or digital media . Active entertainment involves games in which individuals participate. Sensory stimulation is immediate gratification from behaviors such as eating or sexual intercourse. Consumption [ edit ] Main article: Consumer behaviour Humans operate as consumers that obtain and use goods. All production is ultimately designed for consumption , and consumers adapt their behavior based on the availability of production. Mass consumption began during the Industrial Revolution, caused by the development of new technologies that allowed for increased production. Many factors affect a consumer's decision to purchase goods through trade. They may consider the nature of the product, its associated cost, the convenience of purchase, and the nature of advertising around the product. Cultural factors may influence this decision, as different cultures value different things, and subcultures within these cultures may have distinct priorities as buyers. Social class , including wealth, education, and occupation may affect one's purchasing behavior. A consumer's interpersonal relationships and reference groups may also influence purchasing behavior. Ecological behavior [ edit ] Main article: Human ecology A girl with lambs in Gilandeh , Iran (2018) Like all living things, humans live in ecosystems and interact with other organisms. Human behavior is affected by the environment in which a human lives, and environments are affected by human habitation. Humans have also developed man-made ecosystems such as urban areas and agricultural land . Geography and landscape ecology determine how humans are distributed within an ecosystem, both naturally and through planned urban morphology . Humans exercise control over the animals that live within their environment. Domesticated animals are trained and cared for by humans. Humans can develop social and emotional bonds with animals in their care. Pets are kept for companionship within human homes, including dogs and cats that have been bred for domestication over many centuries. Livestock animals, such as cattle , sheep , goats , and poultry , are kept on agricultural land to produce animal products . Domesticated animals are also kept in laboratories for animal testing . Non-domesticated animals are sometimes kept in nature reserves and zoos for tourism and conservation . Causes and factors [ edit ] Human behavior is influenced by biological and cultural elements. The structure and agency debate considers whether human behavior is predominantly led by individual human impulses or by external structural forces. Behavioral genetics considers how human behavior is affected by inherited traits. Though genes do not guarantee certain behaviors, certain traits can be inherited that make individuals more likely to engage in certain behaviors or express certain personalities. An individual's environment can also affect behavior, often in conjunction with genetic factors. An individual's personality and attitudes affect how behaviors are expressed, formed in conjunction by genetic and environmental factors. Age [ edit ] Further information: Ageing An infant engaging in play in Los Angeles , California (2015) Infants are limited in their ability to interpret their surroundings shortly after birth. Object permanence and understanding of motion typically develop within the first six months of an infant's life, though the specific cognitive processes are not understood. The ability to mentally categorize different concepts and objects that they perceive also develops within the first year. Infants are quickly able to discern their body from their surroundings and often take interest in their own limbs or actions they cause by two months of age. Infants practice imitation of other individuals to engage socially and learn new behaviors. In young infants, this involves imitating facial expressions , and imitation of tool use takes place within the first year. Communication develops over the first year, and infants begin using gestures to communicate intention around nine to ten months of age. Verbal communication develops more gradually, taking form during the second year of age. Children develop fine motor skills shortly after infancy, in the range of three to six years of age, allowing them to engage in behaviors using the hands and eye–hand coordination and perform basic activities of self sufficiency . Children begin expressing more complex emotions in the three- to six-year-old range, including humor, empathy, and altruism, as well engaging in creativity and inquiry. Aggressive behaviors also become varied at this age as children engage in increased physical aggression before learning to favor diplomacy over aggression. Children at this age can express themselves using language with basic grammar. As children grow older, they develop emotional intelligence . Young children engage in basic social behaviors with peers , typically forming friendships centered on play with individuals of the same age and gender. Behaviors of young children are centered around play, which allows them to practice physical, cognitive, and social behaviors. Basic self-concept first develops as children grow, particularly centered around traits such as gender and ethnicity, and behavior is heavily affected by peers for the first time. Adolescents undergo changes in behavior caused by puberty and the associated changes in hormone production. Production of testosterone increases sensation seeking and sensitivity to rewards in adolescents as well as aggression and risk-taking in adolescent boys. Production of estradiol causes similar risk-taking behavior among adolescent girls. The new hormones cause changes in emotional processing that allow for close friendships, stronger motivations and intentions, and adolescent sexuality . Adolescents undergo social changes on a large scale, developing a full self-concept and making autonomous decisions independently of adults. They typically become more aware of social norms and social cues than children, causing an increase in self-consciousness and adolescent egocentrism that guides behavior in social settings throughout adolescence. Culture and environment [ edit ] Human brains, as with those of all mammals, are neuroplastic . This means that the structure of the brain changes over time as neural pathways are altered in response to the environment. Many behaviors are learned through interaction with others during early development of the brain. Human behavior is distinct from the behavior of other animals in that it is heavily influenced by culture and language. Social learning allows humans to develop new behaviors by following the example of others. Culture is also the guiding influence that defines social norms. Genetics [ edit ] Physiology [ edit ] Neurotransmitters , hormones , and metabolism are all recognized as biological factors in human behavior. Physical disabilities can prevent individuals from engaging in typical human behavior or necessitate alternative behaviors. Accommodations and accessibility are often made available for individuals with physical disabilities in developed nations, including health care, assistive technology , and vocational services . Severe disabilities are associated with increased leisure time but also with a lower satisfaction in the quality of leisure time. Productivity and health both commonly undergo long term decline following the onset of a severe disability. Mental disabilities are those that directly affect cognitive and social behavior. Common mental disorders include mood disorders , anxiety disorders , personality disorders , and substance dependence . See also [ edit ] Psychology portal Society portal Behavioral modernity Behaviorism Cultural ecology Human behavioral ecology References [ edit ] ^ Longino 2013 , pp. 13–14. ^ Longino 2013 , pp. 7–8. ^ Longino 2013 , p. 2. ^ Longino 2013 , p. 11. ^ Longino 2013 , p. 1. ^ Longino 2013 , p. 8. ^ Longino 2013 , pp. 9–10. ^ Longino 2013 , p. 12. ^ Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 . ^ Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 . ^ Duck 2007 , pp. 1–5. ^ Duck 2007 , pp. 10–14. ^ Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 . ^ Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 . ^ Goode 2015 , pp. 3–4. ^ Goode 2015 , p. 7. ^ Goode 2015 , p. 5. ^ Goode 2015 , p. 6. ^ Duck 2007 , p. 107. ^ Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 . ^ Duck 2007 , pp. 56–60. ^ Duck 2007 , pp. 121–125. ^ Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 . ^ Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 . ^ Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 . ^ Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation. ^ Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 . ^ Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 . ^ Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 . ^ Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 . ^ Evans 2003 , pp. 1–21. ^ Evans 2003 , pp. 47–. ^ Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 . ^ Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 . ^ " 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 . ^ Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 . ^ Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 . ^ Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 . ^ McKeown, Thomas (1980). The Role of Medicine . Princeton University Press. p. 78. ISBN 978-1400854622 . ^ Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 . ^ Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 . ^ Baggott, L. M. (1997). Human Reproduction . Cambridge University Press. p. 5. ISBN 978-0521469142 . ^ Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 . ^ Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 . ^ Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 . ^ Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 . ^ Neff 1985 , pp. 24–33. ^ Neff 1985 , pp. 41–46. ^ Neff 1985 , p. 2. ^ Neff 1985 , pp. 142–153. ^ Neff 1985 , pp. 79–80. ^ Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 . ^ Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 . ^ Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X . ^ Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 . ^ Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 . ^ Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 . ^ Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 . ^ Bremner & Wachs 2010 , pp. 234–235. ^ Bremner & Wachs 2010 , pp. 264–265. ^ Bremner & Wachs 2010 , pp. 337–340. ^ Bremner & Wachs 2010 , pp. 346–347. ^ Bremner & Wachs 2010 , pp. 398–399. ^ Woody & Woody 2019 , pp. 259–260. ^ Woody & Woody 2019 , p. 263. ^ Woody & Woody 2019 , p. 279. ^ Woody & Woody 2019 , pp. 268–269. ^ Charlesworth 2019 , p. 346. ^ Woody & Woody 2019 , p. 281. ^ Woody & Woody 2019 , p. 290. ^ Charlesworth 2019 , p. 343. ^ Charlesworth 2019 , p. 353. ^ Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 . ^ Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 . ^ Van Schaik 2016 , Chapter 2.4. ^ Van Schaik 2016 , Chapter 3.1. ^ Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 . ^ Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 . ^ Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 . Bibliography [ edit ] Bremner, Gavin; Wachs, Theodore D., eds. (2010). The Wiley-Blackwell Handbook of Infant Development . Vol. 1: Basic Research (2nd ed.). Wiley-Blackwell. ISBN 978-1444332735 . Charlesworth, Leanne Wood (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 327–395. ISBN 978-1544339344 . LCCN 2018021374 . Duck, Steve (2007). Human Relationships (4th ed.). SAGE Publications. ISBN 978-1412929998 . Evans, Dylan (2003). Emotion: A Very Short Introduction . Oxford University Press. ISBN 978-0192804617 . Goode, Erich (2015). "The Sociology of Deviance: An Introduction". In Goode, Erich (ed.). The Handbook of Deviance . Wiley. pp. 3–29. doi : 10.1002/9781118701386 . ISBN 978-1118701324 . Longino, Helen E. (2013). Studying Human Behavior: How Scientists Investigate Aggression and Sexuality . University of Chicago Press. doi : 10.7208/9780226921822 (inactive 31 January 2024). ISBN 978-0226921822 . {{ cite book }} : CS1 maint: DOI inactive as of January 2024 ( link ) Neff, Walter S. (1985). Work and Human Behavior (3rd ed.). Aldine Publishing Company. ISBN 0202303195 . Van Schaik, Carel P. (2016). The primate origins of human nature . Foundations of human biology. Hoboken, New Jersey: Wiley-Blackwell. ISBN 978-1-119-11820-6 . Woody, Debra J.; Woody, David (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 251–326. ISBN 978-1544339344 . LCCN 2018021374 . Further reading [ edit ] Ardrey, Robert . 1970. The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder . Atheneum . ISBN 0689103476 . Sapolsky, Robert M. (2017). Behave: The Biology of Humans at Our Best and Worst . Penguin Press. ISBN 978-1594205071 . External links [ edit ] Wikiquote has quotations related to Human behavior . Media related to Human behavior at Wikimedia Commons Authority control databases International FAST National France BnF data Israel United States Japan Czech Republic Other NARA Retrieved from " https://en.wikipedia.org/w/index.php?title=Human_behavior&oldid=1215120043 " Categories : Human behavior Behavior Culture Humans Main topic articles Hidden categories: Articles with short description Short description is different from Wikidata Use American English from February 2020 All Wikipedia articles written in American English CS1: long volume value CS1 maint: DOI inactive as of January 2024 Commons category link is on Wikidata Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with J9U identifiers Articles with LCCN identifiers Articles with NDL identifiers Articles with NKC identifiers Articles with NARA identifiers This page was last edited on 23 March 2024, at 06:25 (UTC) . Text is available under the Creative Commons Attribution-ShareAlike License 4.0 ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy . Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. , a non-profit organization. Privacy policy About Wikipedia Disclaimers Contact Wikipedia Code of Conduct Developers Statistics Cookie statement Mobile view
Contents move to sidebar hide (Top) 1 Study 2 Social behavior Toggle Social behavior subsection 2.1 Social norms 2.2 Interpersonal relationships 2.3 Politics and conflict 3 Cognitive behavior 4 Physiological behavior 5 Economic behavior Toggle Economic behavior subsection 5.1 Work 5.2 Leisure 5.3 Consumption 6 Ecological behavior 7 Causes and factors Toggle Causes and factors subsection 7.1 Age 7.2 Culture and environment 7.3 Genetics 7.4 Physiology 8 See also 9 References 10 Bibliography 11 Further reading 12 External links Toggle the table of contents Human behavior 22 languages العربية বাংলা Català Deutsch Español Esperanto فارسی Français 한국어 Հայերեն हिन्दी Bahasa Indonesia עברית Қазақша Kiswahili Bahasa Melayu Slovenčina Suomi Українська اردو 粵語 中文 Edit links Article Talk English Read Edit View history Tools Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote From Wikipedia, the free encyclopedia Array of every physical action and observable emotion associated with humans For the song, see Human Behaviour . Social interaction and creative expression are forms of human behavior Part of a series on Sociology History Outline Index Key themes Society Globalization Human behavior Human environmental impact Identity Industrial revolutions 3 / 4 / 5 Social complexity Social construct Social environment Social equality Social equity Social power Social stratification Social structure Perspectives Conflict theory Critical theory Structural functionalism Positivism Social constructionism Symbolic interactionism Branches Aging Architecture Art Astrosociology Body Criminology Consciousness Culture Death Demography Deviance Disaster Economic Education Emotion ( Jealousy ) Environmental Family Feminist Fiscal Food Gender Generations Health Historical Immigration Industrial Internet Jewry Knowledge Language Law Leisure Literature Marxist Mathematic Medical Military Music Peace, war, and social conflict Philosophy Political Public Punishment Race and ethnicity Religion Rural Science ( History of science ) Social movements Social psychology Sociocybernetics Sociology Space Sport Technology Terrorism Urban Utopian Victimology Visual Methods Quantitative Qualitative Comparative Computational Ethnographic Conversation analysis Historical Interview Mathematical Network analysis Social experiment Survey Sociologists 1700s: Comte · Sieyès 1800s: Martineau · Tocqueville · Marx · Spencer · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Marcuse 1900s: Fromm · Adorno · Merton · Mills · Goffman · Bauman · Foucault · Habermas · Baudrillard · Bourdieu · Giddens Lists Bibliography Terminology Journals Organizations People Timeline By country Society portal v t e Human behavior is the potential and expressed capacity ( mentally , physically , and socially ) of human individuals or groups to respond to internal and external stimuli throughout their life. Behavior is driven by genetic and environmental factors that affect an individual. Behavior is also driven, in part, by thoughts and feelings , which provide insight into individual psyche , revealing such things as attitudes and values . Human behavior is shaped by psychological traits , as personality types vary from person to person, producing different actions and behavior. Social behavior accounts for actions directed at others. It is concerned with the considerable influence of social interaction and culture , as well as ethics , interpersonal relationships , politics , and conflict . Some behaviors are common while others are unusual. The acceptability of behavior depends upon social norms and is regulated by various means of social control . Social norms also condition behavior, whereby humans are pressured into following certain rules and displaying certain behaviors that are deemed acceptable or unacceptable depending on the given society or culture. Cognitive behavior accounts for actions of obtaining and using knowledge . It is concerned with how information is learned and passed on, as well as creative application of knowledge and personal beliefs such as religion . Physiological behavior accounts for actions to maintain the body. It is concerned with basic bodily functions as well as measures taken to maintain health. Economic behavior accounts for actions regarding the development, organization, and use of materials as well as other forms of work . Ecological behavior accounts for actions involving the ecosystem. It is concerned with how humans interact with other organisms and how the environment shapes human behavior. Study [ edit ] Main article: Human ethology Human behavior is studied by the social sciences , which include psychology , sociology , ethology , and their various branches and schools of thought. There are many different facets of human behavior, and no one definition or field study encompasses it in its entirety. The nature versus nurture debate is one of the fundamental divisions in the study of human behavior; this debate considers whether behavior is predominantly affected by genetic or environmental factors. The study of human behavior sometimes receives public attention due to its intersection with cultural issues, including crime , sexuality , and social inequality . Some natural sciences also place emphasis on human behavior. Neurology and evolutionary biology , study how behavior is controlled by the nervous system and how the human mind evolved , respectively. In other fields, human behavior may be a secondary subject of study when considering how it affects another subject. Outside of formal scientific inquiry, human behavior and the human condition is also a major focus of philosophy and literature . Philosophy of mind considers aspects such as free will , the mind–body problem , and malleability of human behavior. Human behavior may be evaluated through questionnaires , interviews , and experimental methods . Animal testing may also be used to test behaviors that can then be compared to human behavior. Twin studies are a common method by which human behavior is studied. Twins with identical genomes can be compared to isolate genetic and environmental factors in behavior. Lifestyle, susceptibility to disease, and unhealthy behaviors have been identified to have both genetic and environmental indicators through twin studies. Social behavior [ edit ] Further information: Sociology Women bowing in Japan ( c. 1880 ) Human social behavior is the behavior that considers other humans, including communication and cooperation. It is highly complex and structured, based on advanced theory of mind that allows humans to attribute thoughts and actions to one another. Through social behavior, humans have developed society and culture distinct from other animals. Human social behavior is governed by a combination of biological factors that affect all humans and cultural factors that change depending on upbringing and societal norms. Human communication is based heavily on language , typically through speech or writing . Nonverbal communication and paralanguage can modify the meaning of communications by demonstrating ideas and intent through physical and vocal behaviors. Social norms [ edit ] Human behavior in a society is governed by social norms . Social norms are unwritten expectations that members of society have for one another. These norms are ingrained in the particular culture that they emerge from, and humans often follow them unconsciously or without deliberation. These norms affect every aspect of life in human society, including decorum , social responsibility , property rights , contractual agreement , morality , justice , and meaning . Many norms facilitate coordination between members of society and prove mutually beneficial, such as norms regarding communication and agreements. Norms are enforced by social pressure , and individuals that violate social norms risk social exclusion . Systems of ethics are used to guide human behavior to determine what is moral. Humans are distinct from other animals in the use of ethical systems to determine behavior. Ethical behavior is human behavior that takes into consideration how actions will affect others and whether behaviors will be optimal for others. What constitutes ethical behavior is determined by the individual value judgments of the person and the collective social norms regarding right and wrong. Value judgments are intrinsic to people of all cultures, though the specific systems used to evaluate them may vary. These systems may be derived from divine law , natural law , civil authority , reason , or a combination of these and other principles. Altruism is an associated behavior in which humans consider the welfare of others equally or preferentially to their own. While other animals engage in biological altruism, ethical altruism is unique to humans. Deviance is behavior that violates social norms. As social norms vary between individuals and cultures, the nature and severity of a deviant act is subjective. What is considered deviant by a society may also change over time as new social norms are developed. Deviance is punished by other individuals through social stigma , censure , or violence . Many deviant actions are recognized as crimes and punished through a system of criminal justice . Deviant actions may be punished to prevent harm to others, to maintain a particular worldview and way of life, or to enforce principles of morality and decency . Cultures also attribute positive or negative value to certain physical traits, causing individuals that do not have desirable traits to be seen as deviant. Interpersonal relationships [ edit ] Main article: Interpersonal relationship A family in Noatak , Alaska (1929) Interpersonal relationships can be evaluated by the specific choices and emotions between two individuals, or they can be evaluated by the broader societal context of how such a relationship is expected to function. Relationships are developed through communication, which creates intimacy, expresses emotions, and develops identity. An individual's interpersonal relationships form a social group in which individuals all communicate and socialize with one another, and these social groups are connected by additional relationships. Human social behavior is affected not only by individual relationships, but also by how behaviors in one relationship may affect others. Individuals that actively seek out social interactions are extraverts , and those that do not are introverts. Romantic love is a significant interpersonal attraction toward another. Its nature varies by culture, but it is often contingent on gender, occurring in conjunction with sexual attraction and being either heterosexual or homosexual . It takes different forms and is associated with many individual emotions. Many cultures place a higher emphasis on romantic love than other forms of interpersonal attraction. Marriage is a union between two people, though whether it is associated with romantic love is dependent on the culture. Individuals that are closely related by consanguinity form a family . There are many variations on family structures that may include parents and children as well as stepchildren or extended relatives. Family units with children emphasize parenting , in which parents engage in a high level of parental investment to protect and instruct children as they develop over a period of time longer than that of most other mammals. Politics and conflict [ edit ] Further information: Political science , Theories of political behavior , and Conflict (process) A depiction of men fighting in the First Battle of Komárom (1849) When humans make decisions as a group, they engage in politics. Humans have evolved to engage in behaviors of self-interest , but this also includes behaviors that facilitate cooperation rather than conflict in collective settings. Individuals will often form in-group and out-group perceptions, through which individuals cooperate with the in-group and compete with the out-group. This causes behaviors such as unconsciously conforming, passively obeying authority, taking pleasure in the misfortune of opponents, initiating hostility toward out-group members, artificially creating out-groups when none exist, and punishing those that do not comply with the standards of the in-group. These behaviors lead to the creation of political systems that enforce in-group standards and norms. When humans oppose one another, it creates conflict. It may occur when the involved parties have a disagreement of opinion, when one party obstructs the goals of another, or when parties experience negative emotions such as anger toward one another. Conflicts purely of disagreement are often resolved through communication or negotiation , but incorporation of emotional or obstructive aspects can escalate conflict. Interpersonal conflict is that between specific individuals or groups of individuals. Social conflict is that between different social groups or demographics. This form of conflict often takes place when groups in society are marginalized, do not have the resources they desire, wish to instigate social change, or wish to resist social change. Significant social conflict can cause civil disorder . International conflict is that between nations or governments. It may be solved through diplomacy or war . Cognitive behavior [ edit ] Main article: Cognition People being taught to paint in Volgograd , Russia (2013) Human cognition is distinct from that of other animals. This is derived from biological traits of human cognition, but also from shared knowledge and development passed down culturally. Humans are able to learn from one another due to advanced theory of mind that allows knowledge to be obtained through education . The use of language allows humans to directly pass knowledge to one another. The human brain has neuroplasticity , allowing it to modify its features in response to new experiences. This facilitates learning in humans and leads to behaviors of practice , allowing the development of new skills in individual humans. Behavior carried out over time can be ingrained as a habit , where humans will continue to regularly engage in the behavior without consciously deciding to do so. Humans engage in reason to make inferences with a limited amount of information. Most human reasoning is done automatically without conscious effort on the part of the individual. Reasoning is carried out by making generalizations from past experiences and applying them to new circumstances. Learned knowledge is acquired to make more accurate inferences about the subject. Deductive reasoning infers conclusions that are true based on logical premises, while inductive reasoning infers what conclusions are likely to be true based on context. Emotion is a cognitive experience innate to humans. Basic emotions such as joy , distress , anger , fear , surprise , and disgust are common to all cultures, though social norms regarding the expression of emotion may vary. Other emotions come from higher cognition, such as love , guilt , shame , embarrassment , pride , envy , and jealousy . These emotions develop over time rather than instantly and are more strongly influenced by cultural factors. Emotions are influenced by sensory information , such as color and music , and moods of happiness and sadness . Humans typically maintain a standard level of happiness or sadness determined by health and social relationships, though positive and negative events have short-term influences on mood. Humans often seek to improve the moods of one another through consolation , entertainment , and venting . Humans can also self-regulate mood through exercise and meditation . Creativity is the use of previous ideas or resources to produce something original. It allows for innovation , adaptation to change, learning new information, and novel problem solving. Expression of creativity also supports quality of life . Creativity includes personal creativity, in which a person presents new ideas authentically , but it can also be expanded to social creativity, in which a community or society produces and recognizes ideas collectively. Creativity is applied in typical human life to solve problems as they occur. It also leads humans to carry out art and science . Individuals engaging in advanced creative work typically have specialized knowledge in that field, and humans draw on this knowledge to develop novel ideas. In art, creativity is used to develop new artistic works, such as visual art or music . In science, those with knowledge in a particular scientific field can use trial and error to develop theories that more accurately explain phenomena. Religious behavior is a set of traditions that are followed based on the teachings of a religious belief system. The nature of religious behavior varies depending on the specific religious traditions. Most religious traditions involve variations of telling myths , practicing rituals , making certain things taboo , adopting symbolism , determining morality, experiencing altered states of consciousness , and believing in supernatural beings. Religious behavior is often demanding and has high time, energy, and material costs, and it conflicts with rational choice models of human behavior, though it does provide community-related benefits. Anthropologists offer competing theories as to why humans adopted religious behavior. Religious behavior is heavily influenced by social factors, and group involvement is significant in the development of an individual's religious behavior. Social structures such as religious organizations or family units allow the sharing and coordination of religious behavior. These social connections reinforce the cognitive behaviors associated with religion, encouraging orthodoxy and commitment. According to a Pew Research Center report, 54% of adults around the world state that religion is very important in their lives as of 2018. Physiological behavior [ edit ] See also: Psychophysiology A boy eating in Harare , Zimbabwe (2017) Humans undergo many behaviors common to animals to support the processes of the human body . Humans eat food to obtain nutrition . These foods may be chosen for their nutritional value, but they may also be eaten for pleasure . Eating often follows a food preparation process to make it more enjoyable. Humans dispose of excess food through waste . Excrement is often treated as taboo, particularly in developed and urban communities where sanitation is more widely available and excrement has no value as fertilizer . Humans also regularly engage in sleep , based on homeostatic and circadian factors. The circadian rhythm causes humans to require sleep at a regular pattern and is typically calibrated to the day-night cycle and sleep-wake habits. Homeostasis is also be maintained, causing longer sleep longer after periods of sleep deprivation . The human sleep cycle takes place over 90 minutes, and it repeats 3–5 times during normal sleep. There are also unique behaviors that humans undergo to maintain physical health. Humans have developed medicine to prevent and treat illnesses. In industrialized nations, eating habits that favor better nutrition, hygienic behaviors that promote sanitation , medical treatment to eradicate diseases, and the use of birth control significantly improve human health. Humans can also engage in exercise beyond that required for survival to maintain health. Humans engage in hygiene to limit exposure to dirt and pathogens . Some of these behaviors are adaptive while others are learned. Basic behaviors of disgust evolved as an adaptation to prevent contact with sources of pathogens, resulting in a biological aversion to feces , body fluids , rotten food , and animals that are commonly disease vectors . Personal grooming , disposal of human corpses , use of sewerage , and use of cleaning agents are hygienic behaviors common to most human societies. Humans reproduce sexually , engaging in sexual intercourse for both reproduction and sexual pleasure . Human reproduction is closely associated with human sexuality and an instinctive desire to procreate , though humans are unique in that they intentionally control the number of offspring that they produce. Humans engage in a large variety of reproductive behaviors relative to other animals, with various mating structures that include forms of monogamy , polygyny , and polyandry . How humans engage in mating behavior is heavily influenced by cultural norms and customs. Unlike most mammals, human women ovulate spontaneously rather than seasonally, with a menstrual cycle that typically lasts 25–35 days. Humans are bipedal and move by walking . Human walking corresponds to the bipedal gait cycle , which involves alternating heel contact and toe off with the ground and slight elevation and rotation of the pelvis . Balance while walking learned during the first 7–9 years of life, and individual humans develop unique gaits while learning to displace weight, adjust center of mass , and correspond neural control with movement. Humans can achieve higher speed by running . The endurance running hypothesis proposes that humans can outpace most other animals over long distances through running, though human running causes a higher rate of energy exertion. The human body self-regulates through perspiration during periods of exertion, allowing humans more endurance than other animals. The human hand is prehensile and capable of grasping objects and applying force with control over the hand's dexterity and grip strength . This allows the use of complex tools by humans. Economic behavior [ edit ] Further information: Behavioral economics Humans engage in predictable behaviors when considering economic decisions, and these behaviors may or may not be rational . Like all animals, humans make basic decisions through cost–benefit analysis and the risk–return spectrum , though humans are able to contemplate these decisions more thoroughly. Human economic decision making is often reference dependent , in which options are weighed in reference to the status quo rather than absolute gains and losses. Humans are also loss averse , fearing loss rather than seeking gain. Advanced economic behavior developed in humans after the Neolithic Revolution and the development of agriculture . These developments led to a sustainable supply of resources that allowed specialization in more complex societies. Work [ edit ] Main article: Work (human activity) Women tending to farm animals in Mangskogs, Sweden (1911) The nature of human work is defined by the complexity of society. The simplest societies are tribes that work primarily for sustenance as hunter-gatherers . In this sense, work is not a distinct activity but a constant that makes up all parts of life, as all members of the society must work consistently to stay alive. More advanced societies developed after the Neolithic Revolution, emphasizing work in agricultural and pastoral settings. In these societies, production is increased, ending the need for constant work and allowing some individuals to specialize and work in areas outside of food-production. This also created non-laborious work, as increasing occupational complexity required some individuals to specialize in technical knowledge and administration. Laborious work in these societies has variously been carried out by slaves, serfs, peasants, and guild craftsmen. The nature of work changed significantly during the Industrial Revolution in which the factory system was developed for use by industrializing nations. In addition to further increasing general quality of life, this development changed the dynamic of work. Under the factory system, workers increasingly collaborate with others, employers serve as authority figures during work hours, and forced labor is largely eradicated. Further changes occur in post-industrial societies where technological advance makes industries obsolete, replacing them with mass production and service industries . Humans approach work differently based on both physical and personal attributes, and some work with more effectiveness and commitment than others. Some find work to contribute to personal fulfillment, while others work only out of necessity. Work can also serve as an identity, with individuals identifying themselves based on their occupation. Work motivation is complex, both contributing to and subtracting from various human needs. The primary motivation for work is for material gain, which takes the form of money in modern societies. It may also serve to create self-esteem and personal worth, provide activity, gain respect, and express creativity. Modern work is typically categorized as laborious or blue-collar work and non-laborious or white-collar work . Leisure [ edit ] Main article: Leisure Men playing association football in Kilkenny , Ireland (2007) Leisure is activity or lack of activity that takes place outside of work. It provides relaxation, entertainment , and improved quality of life for individuals. Engaging in leisure can be beneficial for physical and mental health. It may be used to seek temporary relief from psychological stress , to produce positive emotions, or to facilitate social interaction. Leisure can also facilitate health risks and negative emotions caused by boredom , substance abuse , or high-risk behavior . Leisure may be defined as serious or casual. Serious leisure behaviors involve non-professional pursuit of arts and sciences, the development of hobbies , or career volunteering in an area of expertise. Casual leisure behaviors provide short-term gratification, but they do not provide long-term gratification or personal identity. These include play , relaxation, casual social interaction, volunteering , passive entertainment, active entertainment, and sensory stimulation. Passive entertainment is typically derived from mass media , which may include written works or digital media . Active entertainment involves games in which individuals participate. Sensory stimulation is immediate gratification from behaviors such as eating or sexual intercourse. Consumption [ edit ] Main article: Consumer behaviour Humans operate as consumers that obtain and use goods. All production is ultimately designed for consumption , and consumers adapt their behavior based on the availability of production. Mass consumption began during the Industrial Revolution, caused by the development of new technologies that allowed for increased production. Many factors affect a consumer's decision to purchase goods through trade. They may consider the nature of the product, its associated cost, the convenience of purchase, and the nature of advertising around the product. Cultural factors may influence this decision, as different cultures value different things, and subcultures within these cultures may have distinct priorities as buyers. Social class , including wealth, education, and occupation may affect one's purchasing behavior. A consumer's interpersonal relationships and reference groups may also influence purchasing behavior. Ecological behavior [ edit ] Main article: Human ecology A girl with lambs in Gilandeh , Iran (2018) Like all living things, humans live in ecosystems and interact with other organisms. Human behavior is affected by the environment in which a human lives, and environments are affected by human habitation. Humans have also developed man-made ecosystems such as urban areas and agricultural land . Geography and landscape ecology determine how humans are distributed within an ecosystem, both naturally and through planned urban morphology . Humans exercise control over the animals that live within their environment. Domesticated animals are trained and cared for by humans. Humans can develop social and emotional bonds with animals in their care. Pets are kept for companionship within human homes, including dogs and cats that have been bred for domestication over many centuries. Livestock animals, such as cattle , sheep , goats , and poultry , are kept on agricultural land to produce animal products . Domesticated animals are also kept in laboratories for animal testing . Non-domesticated animals are sometimes kept in nature reserves and zoos for tourism and conservation . Causes and factors [ edit ] Human behavior is influenced by biological and cultural elements. The structure and agency debate considers whether human behavior is predominantly led by individual human impulses or by external structural forces. Behavioral genetics considers how human behavior is affected by inherited traits. Though genes do not guarantee certain behaviors, certain traits can be inherited that make individuals more likely to engage in certain behaviors or express certain personalities. An individual's environment can also affect behavior, often in conjunction with genetic factors. An individual's personality and attitudes affect how behaviors are expressed, formed in conjunction by genetic and environmental factors. Age [ edit ] Further information: Ageing An infant engaging in play in Los Angeles , California (2015) Infants are limited in their ability to interpret their surroundings shortly after birth. Object permanence and understanding of motion typically develop within the first six months of an infant's life, though the specific cognitive processes are not understood. The ability to mentally categorize different concepts and objects that they perceive also develops within the first year. Infants are quickly able to discern their body from their surroundings and often take interest in their own limbs or actions they cause by two months of age. Infants practice imitation of other individuals to engage socially and learn new behaviors. In young infants, this involves imitating facial expressions , and imitation of tool use takes place within the first year. Communication develops over the first year, and infants begin using gestures to communicate intention around nine to ten months of age. Verbal communication develops more gradually, taking form during the second year of age. Children develop fine motor skills shortly after infancy, in the range of three to six years of age, allowing them to engage in behaviors using the hands and eye–hand coordination and perform basic activities of self sufficiency . Children begin expressing more complex emotions in the three- to six-year-old range, including humor, empathy, and altruism, as well engaging in creativity and inquiry. Aggressive behaviors also become varied at this age as children engage in increased physical aggression before learning to favor diplomacy over aggression. Children at this age can express themselves using language with basic grammar. As children grow older, they develop emotional intelligence . Young children engage in basic social behaviors with peers , typically forming friendships centered on play with individuals of the same age and gender. Behaviors of young children are centered around play, which allows them to practice physical, cognitive, and social behaviors. Basic self-concept first develops as children grow, particularly centered around traits such as gender and ethnicity, and behavior is heavily affected by peers for the first time. Adolescents undergo changes in behavior caused by puberty and the associated changes in hormone production. Production of testosterone increases sensation seeking and sensitivity to rewards in adolescents as well as aggression and risk-taking in adolescent boys. Production of estradiol causes similar risk-taking behavior among adolescent girls. The new hormones cause changes in emotional processing that allow for close friendships, stronger motivations and intentions, and adolescent sexuality . Adolescents undergo social changes on a large scale, developing a full self-concept and making autonomous decisions independently of adults. They typically become more aware of social norms and social cues than children, causing an increase in self-consciousness and adolescent egocentrism that guides behavior in social settings throughout adolescence. Culture and environment [ edit ] Human brains, as with those of all mammals, are neuroplastic . This means that the structure of the brain changes over time as neural pathways are altered in response to the environment. Many behaviors are learned through interaction with others during early development of the brain. Human behavior is distinct from the behavior of other animals in that it is heavily influenced by culture and language. Social learning allows humans to develop new behaviors by following the example of others. Culture is also the guiding influence that defines social norms. Genetics [ edit ] Physiology [ edit ] Neurotransmitters , hormones , and metabolism are all recognized as biological factors in human behavior. Physical disabilities can prevent individuals from engaging in typical human behavior or necessitate alternative behaviors. Accommodations and accessibility are often made available for individuals with physical disabilities in developed nations, including health care, assistive technology , and vocational services . Severe disabilities are associated with increased leisure time but also with a lower satisfaction in the quality of leisure time. Productivity and health both commonly undergo long term decline following the onset of a severe disability. Mental disabilities are those that directly affect cognitive and social behavior. Common mental disorders include mood disorders , anxiety disorders , personality disorders , and substance dependence . See also [ edit ] Psychology portal Society portal Behavioral modernity Behaviorism Cultural ecology Human behavioral ecology References [ edit ] ^ Longino 2013 , pp. 13–14. ^ Longino 2013 , pp. 7–8. ^ Longino 2013 , p. 2. ^ Longino 2013 , p. 11. ^ Longino 2013 , p. 1. ^ Longino 2013 , p. 8. ^ Longino 2013 , pp. 9–10. ^ Longino 2013 , p. 12. ^ Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 . ^ Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 . ^ Duck 2007 , pp. 1–5. ^ Duck 2007 , pp. 10–14. ^ Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 . ^ Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 . ^ Goode 2015 , pp. 3–4. ^ Goode 2015 , p. 7. ^ Goode 2015 , p. 5. ^ Goode 2015 , p. 6. ^ Duck 2007 , p. 107. ^ Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 . ^ Duck 2007 , pp. 56–60. ^ Duck 2007 , pp. 121–125. ^ Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 . ^ Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 . ^ Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 . ^ Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation. ^ Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 . ^ Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 . ^ Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 . ^ Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 . ^ Evans 2003 , pp. 1–21. ^ Evans 2003 , pp. 47–. ^ Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 . ^ Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 . ^ " 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 . ^ Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 . ^ Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 . ^ Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 . ^ McKeown, Thomas (1980). The Role of Medicine . Princeton University Press. p. 78. ISBN 978-1400854622 . ^ Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 . ^ Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 . ^ Baggott, L. M. (1997). Human Reproduction . Cambridge University Press. p. 5. ISBN 978-0521469142 . ^ Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 . ^ Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 . ^ Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 . ^ Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 . ^ Neff 1985 , pp. 24–33. ^ Neff 1985 , pp. 41–46. ^ Neff 1985 , p. 2. ^ Neff 1985 , pp. 142–153. ^ Neff 1985 , pp. 79–80. ^ Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 . ^ Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 . ^ Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X . ^ Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 . ^ Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 . ^ Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 . ^ Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 . ^ Bremner & Wachs 2010 , pp. 234–235. ^ Bremner & Wachs 2010 , pp. 264–265. ^ Bremner & Wachs 2010 , pp. 337–340. ^ Bremner & Wachs 2010 , pp. 346–347. ^ Bremner & Wachs 2010 , pp. 398–399. ^ Woody & Woody 2019 , pp. 259–260. ^ Woody & Woody 2019 , p. 263. ^ Woody & Woody 2019 , p. 279. ^ Woody & Woody 2019 , pp. 268–269. ^ Charlesworth 2019 , p. 346. ^ Woody & Woody 2019 , p. 281. ^ Woody & Woody 2019 , p. 290. ^ Charlesworth 2019 , p. 343. ^ Charlesworth 2019 , p. 353. ^ Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 . ^ Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 . ^ Van Schaik 2016 , Chapter 2.4. ^ Van Schaik 2016 , Chapter 3.1. ^ Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 . ^ Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 . ^ Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 . Bibliography [ edit ] Bremner, Gavin; Wachs, Theodore D., eds. (2010). The Wiley-Blackwell Handbook of Infant Development . Vol. 1: Basic Research (2nd ed.). Wiley-Blackwell. ISBN 978-1444332735 . Charlesworth, Leanne Wood (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 327–395. ISBN 978-1544339344 . LCCN 2018021374 . Duck, Steve (2007). Human Relationships (4th ed.). SAGE Publications. ISBN 978-1412929998 . Evans, Dylan (2003). Emotion: A Very Short Introduction . Oxford University Press. ISBN 978-0192804617 . Goode, Erich (2015). "The Sociology of Deviance: An Introduction". In Goode, Erich (ed.). The Handbook of Deviance . Wiley. pp. 3–29. doi : 10.1002/9781118701386 . ISBN 978-1118701324 . Longino, Helen E. (2013). Studying Human Behavior: How Scientists Investigate Aggression and Sexuality . University of Chicago Press. doi : 10.7208/9780226921822 (inactive 31 January 2024). ISBN 978-0226921822 . {{ cite book }} : CS1 maint: DOI inactive as of January 2024 ( link ) Neff, Walter S. (1985). Work and Human Behavior (3rd ed.). Aldine Publishing Company. ISBN 0202303195 . Van Schaik, Carel P. (2016). The primate origins of human nature . Foundations of human biology. Hoboken, New Jersey: Wiley-Blackwell. ISBN 978-1-119-11820-6 . Woody, Debra J.; Woody, David (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 251–326. ISBN 978-1544339344 . LCCN 2018021374 . Further reading [ edit ] Ardrey, Robert . 1970. The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder . Atheneum . ISBN 0689103476 . Sapolsky, Robert M. (2017). Behave: The Biology of Humans at Our Best and Worst . Penguin Press. ISBN 978-1594205071 . External links [ edit ] Wikiquote has quotations related to Human behavior . Media related to Human behavior at Wikimedia Commons Authority control databases International FAST National France BnF data Israel United States Japan Czech Republic Other NARA Retrieved from " https://en.wikipedia.org/w/index.php?title=Human_behavior&oldid=1215120043 " Categories : Human behavior Behavior Culture Humans Main topic articles Hidden categories: Articles with short description Short description is different from Wikidata Use American English from February 2020 All Wikipedia articles written in American English CS1: long volume value CS1 maint: DOI inactive as of January 2024 Commons category link is on Wikidata Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with J9U identifiers Articles with LCCN identifiers Articles with NDL identifiers Articles with NKC identifiers Articles with NARA identifiers This page was last edited on 23 March 2024, at 06:25 (UTC) . Text is available under the Creative Commons Attribution-ShareAlike License 4.0 ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy . Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. , a non-profit organization. Privacy policy About Wikipedia Disclaimers Contact Wikipedia Code of Conduct Developers Statistics Cookie statement Mobile view
Contents move to sidebar hide (Top) 1 Study 2 Social behavior Toggle Social behavior subsection 2.1 Social norms 2.2 Interpersonal relationships 2.3 Politics and conflict 3 Cognitive behavior 4 Physiological behavior 5 Economic behavior Toggle Economic behavior subsection 5.1 Work 5.2 Leisure 5.3 Consumption 6 Ecological behavior 7 Causes and factors Toggle Causes and factors subsection 7.1 Age 7.2 Culture and environment 7.3 Genetics 7.4 Physiology 8 See also 9 References 10 Bibliography 11 Further reading 12 External links
Contents move to sidebar hide (Top) 1 Study 2 Social behavior Toggle Social behavior subsection 2.1 Social norms 2.2 Interpersonal relationships 2.3 Politics and conflict 3 Cognitive behavior 4 Physiological behavior 5 Economic behavior Toggle Economic behavior subsection 5.1 Work 5.2 Leisure 5.3 Consumption 6 Ecological behavior 7 Causes and factors Toggle Causes and factors subsection 7.1 Age 7.2 Culture and environment 7.3 Genetics 7.4 Physiology 8 See also 9 References 10 Bibliography 11 Further reading 12 External links
Contents move to sidebar hide (Top) 1 Study 2 Social behavior Toggle Social behavior subsection 2.1 Social norms 2.2 Interpersonal relationships 2.3 Politics and conflict 3 Cognitive behavior 4 Physiological behavior 5 Economic behavior Toggle Economic behavior subsection 5.1 Work 5.2 Leisure 5.3 Consumption 6 Ecological behavior 7 Causes and factors Toggle Causes and factors subsection 7.1 Age 7.2 Culture and environment 7.3 Genetics 7.4 Physiology 8 See also 9 References 10 Bibliography 11 Further reading 12 External links
Contents move to sidebar hide (Top) 1 Study 2 Social behavior Toggle Social behavior subsection 2.1 Social norms 2.2 Interpersonal relationships 2.3 Politics and conflict 3 Cognitive behavior 4 Physiological behavior 5 Economic behavior Toggle Economic behavior subsection 5.1 Work 5.2 Leisure 5.3 Consumption 6 Ecological behavior 7 Causes and factors Toggle Causes and factors subsection 7.1 Age 7.2 Culture and environment 7.3 Genetics 7.4 Physiology 8 See also 9 References 10 Bibliography 11 Further reading 12 External links
Toggle the table of contents Human behavior 22 languages العربية বাংলা Català Deutsch Español Esperanto فارسی Français 한국어 Հայերեն हिन्दी Bahasa Indonesia עברית Қазақша Kiswahili Bahasa Melayu Slovenčina Suomi Українська اردو 粵語 中文 Edit links Article Talk English Read Edit View history Tools Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote From Wikipedia, the free encyclopedia Array of every physical action and observable emotion associated with humans For the song, see Human Behaviour . Social interaction and creative expression are forms of human behavior Part of a series on Sociology History Outline Index Key themes Society Globalization Human behavior Human environmental impact Identity Industrial revolutions 3 / 4 / 5 Social complexity Social construct Social environment Social equality Social equity Social power Social stratification Social structure Perspectives Conflict theory Critical theory Structural functionalism Positivism Social constructionism Symbolic interactionism Branches Aging Architecture Art Astrosociology Body Criminology Consciousness Culture Death Demography Deviance Disaster Economic Education Emotion ( Jealousy ) Environmental Family Feminist Fiscal Food Gender Generations Health Historical Immigration Industrial Internet Jewry Knowledge Language Law Leisure Literature Marxist Mathematic Medical Military Music Peace, war, and social conflict Philosophy Political Public Punishment Race and ethnicity Religion Rural Science ( History of science ) Social movements Social psychology Sociocybernetics Sociology Space Sport Technology Terrorism Urban Utopian Victimology Visual Methods Quantitative Qualitative Comparative Computational Ethnographic Conversation analysis Historical Interview Mathematical Network analysis Social experiment Survey Sociologists 1700s: Comte · Sieyès 1800s: Martineau · Tocqueville · Marx · Spencer · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Marcuse 1900s: Fromm · Adorno · Merton · Mills · Goffman · Bauman · Foucault · Habermas · Baudrillard · Bourdieu · Giddens Lists Bibliography Terminology Journals Organizations People Timeline By country Society portal v t e Human behavior is the potential and expressed capacity ( mentally , physically , and socially ) of human individuals or groups to respond to internal and external stimuli throughout their life. Behavior is driven by genetic and environmental factors that affect an individual. Behavior is also driven, in part, by thoughts and feelings , which provide insight into individual psyche , revealing such things as attitudes and values . Human behavior is shaped by psychological traits , as personality types vary from person to person, producing different actions and behavior. Social behavior accounts for actions directed at others. It is concerned with the considerable influence of social interaction and culture , as well as ethics , interpersonal relationships , politics , and conflict . Some behaviors are common while others are unusual. The acceptability of behavior depends upon social norms and is regulated by various means of social control . Social norms also condition behavior, whereby humans are pressured into following certain rules and displaying certain behaviors that are deemed acceptable or unacceptable depending on the given society or culture. Cognitive behavior accounts for actions of obtaining and using knowledge . It is concerned with how information is learned and passed on, as well as creative application of knowledge and personal beliefs such as religion . Physiological behavior accounts for actions to maintain the body. It is concerned with basic bodily functions as well as measures taken to maintain health. Economic behavior accounts for actions regarding the development, organization, and use of materials as well as other forms of work . Ecological behavior accounts for actions involving the ecosystem. It is concerned with how humans interact with other organisms and how the environment shapes human behavior. Study [ edit ] Main article: Human ethology Human behavior is studied by the social sciences , which include psychology , sociology , ethology , and their various branches and schools of thought. There are many different facets of human behavior, and no one definition or field study encompasses it in its entirety. The nature versus nurture debate is one of the fundamental divisions in the study of human behavior; this debate considers whether behavior is predominantly affected by genetic or environmental factors. The study of human behavior sometimes receives public attention due to its intersection with cultural issues, including crime , sexuality , and social inequality . Some natural sciences also place emphasis on human behavior. Neurology and evolutionary biology , study how behavior is controlled by the nervous system and how the human mind evolved , respectively. In other fields, human behavior may be a secondary subject of study when considering how it affects another subject. Outside of formal scientific inquiry, human behavior and the human condition is also a major focus of philosophy and literature . Philosophy of mind considers aspects such as free will , the mind–body problem , and malleability of human behavior. Human behavior may be evaluated through questionnaires , interviews , and experimental methods . Animal testing may also be used to test behaviors that can then be compared to human behavior. Twin studies are a common method by which human behavior is studied. Twins with identical genomes can be compared to isolate genetic and environmental factors in behavior. Lifestyle, susceptibility to disease, and unhealthy behaviors have been identified to have both genetic and environmental indicators through twin studies. Social behavior [ edit ] Further information: Sociology Women bowing in Japan ( c. 1880 ) Human social behavior is the behavior that considers other humans, including communication and cooperation. It is highly complex and structured, based on advanced theory of mind that allows humans to attribute thoughts and actions to one another. Through social behavior, humans have developed society and culture distinct from other animals. Human social behavior is governed by a combination of biological factors that affect all humans and cultural factors that change depending on upbringing and societal norms. Human communication is based heavily on language , typically through speech or writing . Nonverbal communication and paralanguage can modify the meaning of communications by demonstrating ideas and intent through physical and vocal behaviors. Social norms [ edit ] Human behavior in a society is governed by social norms . Social norms are unwritten expectations that members of society have for one another. These norms are ingrained in the particular culture that they emerge from, and humans often follow them unconsciously or without deliberation. These norms affect every aspect of life in human society, including decorum , social responsibility , property rights , contractual agreement , morality , justice , and meaning . Many norms facilitate coordination between members of society and prove mutually beneficial, such as norms regarding communication and agreements. Norms are enforced by social pressure , and individuals that violate social norms risk social exclusion . Systems of ethics are used to guide human behavior to determine what is moral. Humans are distinct from other animals in the use of ethical systems to determine behavior. Ethical behavior is human behavior that takes into consideration how actions will affect others and whether behaviors will be optimal for others. What constitutes ethical behavior is determined by the individual value judgments of the person and the collective social norms regarding right and wrong. Value judgments are intrinsic to people of all cultures, though the specific systems used to evaluate them may vary. These systems may be derived from divine law , natural law , civil authority , reason , or a combination of these and other principles. Altruism is an associated behavior in which humans consider the welfare of others equally or preferentially to their own. While other animals engage in biological altruism, ethical altruism is unique to humans. Deviance is behavior that violates social norms. As social norms vary between individuals and cultures, the nature and severity of a deviant act is subjective. What is considered deviant by a society may also change over time as new social norms are developed. Deviance is punished by other individuals through social stigma , censure , or violence . Many deviant actions are recognized as crimes and punished through a system of criminal justice . Deviant actions may be punished to prevent harm to others, to maintain a particular worldview and way of life, or to enforce principles of morality and decency . Cultures also attribute positive or negative value to certain physical traits, causing individuals that do not have desirable traits to be seen as deviant. Interpersonal relationships [ edit ] Main article: Interpersonal relationship A family in Noatak , Alaska (1929) Interpersonal relationships can be evaluated by the specific choices and emotions between two individuals, or they can be evaluated by the broader societal context of how such a relationship is expected to function. Relationships are developed through communication, which creates intimacy, expresses emotions, and develops identity. An individual's interpersonal relationships form a social group in which individuals all communicate and socialize with one another, and these social groups are connected by additional relationships. Human social behavior is affected not only by individual relationships, but also by how behaviors in one relationship may affect others. Individuals that actively seek out social interactions are extraverts , and those that do not are introverts. Romantic love is a significant interpersonal attraction toward another. Its nature varies by culture, but it is often contingent on gender, occurring in conjunction with sexual attraction and being either heterosexual or homosexual . It takes different forms and is associated with many individual emotions. Many cultures place a higher emphasis on romantic love than other forms of interpersonal attraction. Marriage is a union between two people, though whether it is associated with romantic love is dependent on the culture. Individuals that are closely related by consanguinity form a family . There are many variations on family structures that may include parents and children as well as stepchildren or extended relatives. Family units with children emphasize parenting , in which parents engage in a high level of parental investment to protect and instruct children as they develop over a period of time longer than that of most other mammals. Politics and conflict [ edit ] Further information: Political science , Theories of political behavior , and Conflict (process) A depiction of men fighting in the First Battle of Komárom (1849) When humans make decisions as a group, they engage in politics. Humans have evolved to engage in behaviors of self-interest , but this also includes behaviors that facilitate cooperation rather than conflict in collective settings. Individuals will often form in-group and out-group perceptions, through which individuals cooperate with the in-group and compete with the out-group. This causes behaviors such as unconsciously conforming, passively obeying authority, taking pleasure in the misfortune of opponents, initiating hostility toward out-group members, artificially creating out-groups when none exist, and punishing those that do not comply with the standards of the in-group. These behaviors lead to the creation of political systems that enforce in-group standards and norms. When humans oppose one another, it creates conflict. It may occur when the involved parties have a disagreement of opinion, when one party obstructs the goals of another, or when parties experience negative emotions such as anger toward one another. Conflicts purely of disagreement are often resolved through communication or negotiation , but incorporation of emotional or obstructive aspects can escalate conflict. Interpersonal conflict is that between specific individuals or groups of individuals. Social conflict is that between different social groups or demographics. This form of conflict often takes place when groups in society are marginalized, do not have the resources they desire, wish to instigate social change, or wish to resist social change. Significant social conflict can cause civil disorder . International conflict is that between nations or governments. It may be solved through diplomacy or war . Cognitive behavior [ edit ] Main article: Cognition People being taught to paint in Volgograd , Russia (2013) Human cognition is distinct from that of other animals. This is derived from biological traits of human cognition, but also from shared knowledge and development passed down culturally. Humans are able to learn from one another due to advanced theory of mind that allows knowledge to be obtained through education . The use of language allows humans to directly pass knowledge to one another. The human brain has neuroplasticity , allowing it to modify its features in response to new experiences. This facilitates learning in humans and leads to behaviors of practice , allowing the development of new skills in individual humans. Behavior carried out over time can be ingrained as a habit , where humans will continue to regularly engage in the behavior without consciously deciding to do so. Humans engage in reason to make inferences with a limited amount of information. Most human reasoning is done automatically without conscious effort on the part of the individual. Reasoning is carried out by making generalizations from past experiences and applying them to new circumstances. Learned knowledge is acquired to make more accurate inferences about the subject. Deductive reasoning infers conclusions that are true based on logical premises, while inductive reasoning infers what conclusions are likely to be true based on context. Emotion is a cognitive experience innate to humans. Basic emotions such as joy , distress , anger , fear , surprise , and disgust are common to all cultures, though social norms regarding the expression of emotion may vary. Other emotions come from higher cognition, such as love , guilt , shame , embarrassment , pride , envy , and jealousy . These emotions develop over time rather than instantly and are more strongly influenced by cultural factors. Emotions are influenced by sensory information , such as color and music , and moods of happiness and sadness . Humans typically maintain a standard level of happiness or sadness determined by health and social relationships, though positive and negative events have short-term influences on mood. Humans often seek to improve the moods of one another through consolation , entertainment , and venting . Humans can also self-regulate mood through exercise and meditation . Creativity is the use of previous ideas or resources to produce something original. It allows for innovation , adaptation to change, learning new information, and novel problem solving. Expression of creativity also supports quality of life . Creativity includes personal creativity, in which a person presents new ideas authentically , but it can also be expanded to social creativity, in which a community or society produces and recognizes ideas collectively. Creativity is applied in typical human life to solve problems as they occur. It also leads humans to carry out art and science . Individuals engaging in advanced creative work typically have specialized knowledge in that field, and humans draw on this knowledge to develop novel ideas. In art, creativity is used to develop new artistic works, such as visual art or music . In science, those with knowledge in a particular scientific field can use trial and error to develop theories that more accurately explain phenomena. Religious behavior is a set of traditions that are followed based on the teachings of a religious belief system. The nature of religious behavior varies depending on the specific religious traditions. Most religious traditions involve variations of telling myths , practicing rituals , making certain things taboo , adopting symbolism , determining morality, experiencing altered states of consciousness , and believing in supernatural beings. Religious behavior is often demanding and has high time, energy, and material costs, and it conflicts with rational choice models of human behavior, though it does provide community-related benefits. Anthropologists offer competing theories as to why humans adopted religious behavior. Religious behavior is heavily influenced by social factors, and group involvement is significant in the development of an individual's religious behavior. Social structures such as religious organizations or family units allow the sharing and coordination of religious behavior. These social connections reinforce the cognitive behaviors associated with religion, encouraging orthodoxy and commitment. According to a Pew Research Center report, 54% of adults around the world state that religion is very important in their lives as of 2018. Physiological behavior [ edit ] See also: Psychophysiology A boy eating in Harare , Zimbabwe (2017) Humans undergo many behaviors common to animals to support the processes of the human body . Humans eat food to obtain nutrition . These foods may be chosen for their nutritional value, but they may also be eaten for pleasure . Eating often follows a food preparation process to make it more enjoyable. Humans dispose of excess food through waste . Excrement is often treated as taboo, particularly in developed and urban communities where sanitation is more widely available and excrement has no value as fertilizer . Humans also regularly engage in sleep , based on homeostatic and circadian factors. The circadian rhythm causes humans to require sleep at a regular pattern and is typically calibrated to the day-night cycle and sleep-wake habits. Homeostasis is also be maintained, causing longer sleep longer after periods of sleep deprivation . The human sleep cycle takes place over 90 minutes, and it repeats 3–5 times during normal sleep. There are also unique behaviors that humans undergo to maintain physical health. Humans have developed medicine to prevent and treat illnesses. In industrialized nations, eating habits that favor better nutrition, hygienic behaviors that promote sanitation , medical treatment to eradicate diseases, and the use of birth control significantly improve human health. Humans can also engage in exercise beyond that required for survival to maintain health. Humans engage in hygiene to limit exposure to dirt and pathogens . Some of these behaviors are adaptive while others are learned. Basic behaviors of disgust evolved as an adaptation to prevent contact with sources of pathogens, resulting in a biological aversion to feces , body fluids , rotten food , and animals that are commonly disease vectors . Personal grooming , disposal of human corpses , use of sewerage , and use of cleaning agents are hygienic behaviors common to most human societies. Humans reproduce sexually , engaging in sexual intercourse for both reproduction and sexual pleasure . Human reproduction is closely associated with human sexuality and an instinctive desire to procreate , though humans are unique in that they intentionally control the number of offspring that they produce. Humans engage in a large variety of reproductive behaviors relative to other animals, with various mating structures that include forms of monogamy , polygyny , and polyandry . How humans engage in mating behavior is heavily influenced by cultural norms and customs. Unlike most mammals, human women ovulate spontaneously rather than seasonally, with a menstrual cycle that typically lasts 25–35 days. Humans are bipedal and move by walking . Human walking corresponds to the bipedal gait cycle , which involves alternating heel contact and toe off with the ground and slight elevation and rotation of the pelvis . Balance while walking learned during the first 7–9 years of life, and individual humans develop unique gaits while learning to displace weight, adjust center of mass , and correspond neural control with movement. Humans can achieve higher speed by running . The endurance running hypothesis proposes that humans can outpace most other animals over long distances through running, though human running causes a higher rate of energy exertion. The human body self-regulates through perspiration during periods of exertion, allowing humans more endurance than other animals. The human hand is prehensile and capable of grasping objects and applying force with control over the hand's dexterity and grip strength . This allows the use of complex tools by humans. Economic behavior [ edit ] Further information: Behavioral economics Humans engage in predictable behaviors when considering economic decisions, and these behaviors may or may not be rational . Like all animals, humans make basic decisions through cost–benefit analysis and the risk–return spectrum , though humans are able to contemplate these decisions more thoroughly. Human economic decision making is often reference dependent , in which options are weighed in reference to the status quo rather than absolute gains and losses. Humans are also loss averse , fearing loss rather than seeking gain. Advanced economic behavior developed in humans after the Neolithic Revolution and the development of agriculture . These developments led to a sustainable supply of resources that allowed specialization in more complex societies. Work [ edit ] Main article: Work (human activity) Women tending to farm animals in Mangskogs, Sweden (1911) The nature of human work is defined by the complexity of society. The simplest societies are tribes that work primarily for sustenance as hunter-gatherers . In this sense, work is not a distinct activity but a constant that makes up all parts of life, as all members of the society must work consistently to stay alive. More advanced societies developed after the Neolithic Revolution, emphasizing work in agricultural and pastoral settings. In these societies, production is increased, ending the need for constant work and allowing some individuals to specialize and work in areas outside of food-production. This also created non-laborious work, as increasing occupational complexity required some individuals to specialize in technical knowledge and administration. Laborious work in these societies has variously been carried out by slaves, serfs, peasants, and guild craftsmen. The nature of work changed significantly during the Industrial Revolution in which the factory system was developed for use by industrializing nations. In addition to further increasing general quality of life, this development changed the dynamic of work. Under the factory system, workers increasingly collaborate with others, employers serve as authority figures during work hours, and forced labor is largely eradicated. Further changes occur in post-industrial societies where technological advance makes industries obsolete, replacing them with mass production and service industries . Humans approach work differently based on both physical and personal attributes, and some work with more effectiveness and commitment than others. Some find work to contribute to personal fulfillment, while others work only out of necessity. Work can also serve as an identity, with individuals identifying themselves based on their occupation. Work motivation is complex, both contributing to and subtracting from various human needs. The primary motivation for work is for material gain, which takes the form of money in modern societies. It may also serve to create self-esteem and personal worth, provide activity, gain respect, and express creativity. Modern work is typically categorized as laborious or blue-collar work and non-laborious or white-collar work . Leisure [ edit ] Main article: Leisure Men playing association football in Kilkenny , Ireland (2007) Leisure is activity or lack of activity that takes place outside of work. It provides relaxation, entertainment , and improved quality of life for individuals. Engaging in leisure can be beneficial for physical and mental health. It may be used to seek temporary relief from psychological stress , to produce positive emotions, or to facilitate social interaction. Leisure can also facilitate health risks and negative emotions caused by boredom , substance abuse , or high-risk behavior . Leisure may be defined as serious or casual. Serious leisure behaviors involve non-professional pursuit of arts and sciences, the development of hobbies , or career volunteering in an area of expertise. Casual leisure behaviors provide short-term gratification, but they do not provide long-term gratification or personal identity. These include play , relaxation, casual social interaction, volunteering , passive entertainment, active entertainment, and sensory stimulation. Passive entertainment is typically derived from mass media , which may include written works or digital media . Active entertainment involves games in which individuals participate. Sensory stimulation is immediate gratification from behaviors such as eating or sexual intercourse. Consumption [ edit ] Main article: Consumer behaviour Humans operate as consumers that obtain and use goods. All production is ultimately designed for consumption , and consumers adapt their behavior based on the availability of production. Mass consumption began during the Industrial Revolution, caused by the development of new technologies that allowed for increased production. Many factors affect a consumer's decision to purchase goods through trade. They may consider the nature of the product, its associated cost, the convenience of purchase, and the nature of advertising around the product. Cultural factors may influence this decision, as different cultures value different things, and subcultures within these cultures may have distinct priorities as buyers. Social class , including wealth, education, and occupation may affect one's purchasing behavior. A consumer's interpersonal relationships and reference groups may also influence purchasing behavior. Ecological behavior [ edit ] Main article: Human ecology A girl with lambs in Gilandeh , Iran (2018) Like all living things, humans live in ecosystems and interact with other organisms. Human behavior is affected by the environment in which a human lives, and environments are affected by human habitation. Humans have also developed man-made ecosystems such as urban areas and agricultural land . Geography and landscape ecology determine how humans are distributed within an ecosystem, both naturally and through planned urban morphology . Humans exercise control over the animals that live within their environment. Domesticated animals are trained and cared for by humans. Humans can develop social and emotional bonds with animals in their care. Pets are kept for companionship within human homes, including dogs and cats that have been bred for domestication over many centuries. Livestock animals, such as cattle , sheep , goats , and poultry , are kept on agricultural land to produce animal products . Domesticated animals are also kept in laboratories for animal testing . Non-domesticated animals are sometimes kept in nature reserves and zoos for tourism and conservation . Causes and factors [ edit ] Human behavior is influenced by biological and cultural elements. The structure and agency debate considers whether human behavior is predominantly led by individual human impulses or by external structural forces. Behavioral genetics considers how human behavior is affected by inherited traits. Though genes do not guarantee certain behaviors, certain traits can be inherited that make individuals more likely to engage in certain behaviors or express certain personalities. An individual's environment can also affect behavior, often in conjunction with genetic factors. An individual's personality and attitudes affect how behaviors are expressed, formed in conjunction by genetic and environmental factors. Age [ edit ] Further information: Ageing An infant engaging in play in Los Angeles , California (2015) Infants are limited in their ability to interpret their surroundings shortly after birth. Object permanence and understanding of motion typically develop within the first six months of an infant's life, though the specific cognitive processes are not understood. The ability to mentally categorize different concepts and objects that they perceive also develops within the first year. Infants are quickly able to discern their body from their surroundings and often take interest in their own limbs or actions they cause by two months of age. Infants practice imitation of other individuals to engage socially and learn new behaviors. In young infants, this involves imitating facial expressions , and imitation of tool use takes place within the first year. Communication develops over the first year, and infants begin using gestures to communicate intention around nine to ten months of age. Verbal communication develops more gradually, taking form during the second year of age. Children develop fine motor skills shortly after infancy, in the range of three to six years of age, allowing them to engage in behaviors using the hands and eye–hand coordination and perform basic activities of self sufficiency . Children begin expressing more complex emotions in the three- to six-year-old range, including humor, empathy, and altruism, as well engaging in creativity and inquiry. Aggressive behaviors also become varied at this age as children engage in increased physical aggression before learning to favor diplomacy over aggression. Children at this age can express themselves using language with basic grammar. As children grow older, they develop emotional intelligence . Young children engage in basic social behaviors with peers , typically forming friendships centered on play with individuals of the same age and gender. Behaviors of young children are centered around play, which allows them to practice physical, cognitive, and social behaviors. Basic self-concept first develops as children grow, particularly centered around traits such as gender and ethnicity, and behavior is heavily affected by peers for the first time. Adolescents undergo changes in behavior caused by puberty and the associated changes in hormone production. Production of testosterone increases sensation seeking and sensitivity to rewards in adolescents as well as aggression and risk-taking in adolescent boys. Production of estradiol causes similar risk-taking behavior among adolescent girls. The new hormones cause changes in emotional processing that allow for close friendships, stronger motivations and intentions, and adolescent sexuality . Adolescents undergo social changes on a large scale, developing a full self-concept and making autonomous decisions independently of adults. They typically become more aware of social norms and social cues than children, causing an increase in self-consciousness and adolescent egocentrism that guides behavior in social settings throughout adolescence. Culture and environment [ edit ] Human brains, as with those of all mammals, are neuroplastic . This means that the structure of the brain changes over time as neural pathways are altered in response to the environment. Many behaviors are learned through interaction with others during early development of the brain. Human behavior is distinct from the behavior of other animals in that it is heavily influenced by culture and language. Social learning allows humans to develop new behaviors by following the example of others. Culture is also the guiding influence that defines social norms. Genetics [ edit ] Physiology [ edit ] Neurotransmitters , hormones , and metabolism are all recognized as biological factors in human behavior. Physical disabilities can prevent individuals from engaging in typical human behavior or necessitate alternative behaviors. Accommodations and accessibility are often made available for individuals with physical disabilities in developed nations, including health care, assistive technology , and vocational services . Severe disabilities are associated with increased leisure time but also with a lower satisfaction in the quality of leisure time. Productivity and health both commonly undergo long term decline following the onset of a severe disability. Mental disabilities are those that directly affect cognitive and social behavior. Common mental disorders include mood disorders , anxiety disorders , personality disorders , and substance dependence . See also [ edit ] Psychology portal Society portal Behavioral modernity Behaviorism Cultural ecology Human behavioral ecology References [ edit ] ^ Longino 2013 , pp. 13–14. ^ Longino 2013 , pp. 7–8. ^ Longino 2013 , p. 2. ^ Longino 2013 , p. 11. ^ Longino 2013 , p. 1. ^ Longino 2013 , p. 8. ^ Longino 2013 , pp. 9–10. ^ Longino 2013 , p. 12. ^ Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 . ^ Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 . ^ Duck 2007 , pp. 1–5. ^ Duck 2007 , pp. 10–14. ^ Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 . ^ Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 . ^ Goode 2015 , pp. 3–4. ^ Goode 2015 , p. 7. ^ Goode 2015 , p. 5. ^ Goode 2015 , p. 6. ^ Duck 2007 , p. 107. ^ Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 . ^ Duck 2007 , pp. 56–60. ^ Duck 2007 , pp. 121–125. ^ Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 . ^ Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 . ^ Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 . ^ Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation. ^ Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 . ^ Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 . ^ Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 . ^ Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 . ^ Evans 2003 , pp. 1–21. ^ Evans 2003 , pp. 47–. ^ Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 . ^ Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 . ^ " 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 . ^ Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 . ^ Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 . ^ Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 . ^ McKeown, Thomas (1980). The Role of Medicine . Princeton University Press. p. 78. ISBN 978-1400854622 . ^ Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 . ^ Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 . ^ Baggott, L. M. (1997). Human Reproduction . Cambridge University Press. p. 5. ISBN 978-0521469142 . ^ Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 . ^ Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 . ^ Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 . ^ Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 . ^ Neff 1985 , pp. 24–33. ^ Neff 1985 , pp. 41–46. ^ Neff 1985 , p. 2. ^ Neff 1985 , pp. 142–153. ^ Neff 1985 , pp. 79–80. ^ Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 . ^ Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 . ^ Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X . ^ Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 . ^ Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 . ^ Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 . ^ Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 . ^ Bremner & Wachs 2010 , pp. 234–235. ^ Bremner & Wachs 2010 , pp. 264–265. ^ Bremner & Wachs 2010 , pp. 337–340. ^ Bremner & Wachs 2010 , pp. 346–347. ^ Bremner & Wachs 2010 , pp. 398–399. ^ Woody & Woody 2019 , pp. 259–260. ^ Woody & Woody 2019 , p. 263. ^ Woody & Woody 2019 , p. 279. ^ Woody & Woody 2019 , pp. 268–269. ^ Charlesworth 2019 , p. 346. ^ Woody & Woody 2019 , p. 281. ^ Woody & Woody 2019 , p. 290. ^ Charlesworth 2019 , p. 343. ^ Charlesworth 2019 , p. 353. ^ Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 . ^ Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 . ^ Van Schaik 2016 , Chapter 2.4. ^ Van Schaik 2016 , Chapter 3.1. ^ Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 . ^ Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 . ^ Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 . Bibliography [ edit ] Bremner, Gavin; Wachs, Theodore D., eds. (2010). The Wiley-Blackwell Handbook of Infant Development . Vol. 1: Basic Research (2nd ed.). Wiley-Blackwell. ISBN 978-1444332735 . Charlesworth, Leanne Wood (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 327–395. ISBN 978-1544339344 . LCCN 2018021374 . Duck, Steve (2007). Human Relationships (4th ed.). SAGE Publications. ISBN 978-1412929998 . Evans, Dylan (2003). Emotion: A Very Short Introduction . Oxford University Press. ISBN 978-0192804617 . Goode, Erich (2015). "The Sociology of Deviance: An Introduction". In Goode, Erich (ed.). The Handbook of Deviance . Wiley. pp. 3–29. doi : 10.1002/9781118701386 . ISBN 978-1118701324 . Longino, Helen E. (2013). Studying Human Behavior: How Scientists Investigate Aggression and Sexuality . University of Chicago Press. doi : 10.7208/9780226921822 (inactive 31 January 2024). ISBN 978-0226921822 . {{ cite book }} : CS1 maint: DOI inactive as of January 2024 ( link ) Neff, Walter S. (1985). Work and Human Behavior (3rd ed.). Aldine Publishing Company. ISBN 0202303195 . Van Schaik, Carel P. (2016). The primate origins of human nature . Foundations of human biology. Hoboken, New Jersey: Wiley-Blackwell. ISBN 978-1-119-11820-6 . Woody, Debra J.; Woody, David (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 251–326. ISBN 978-1544339344 . LCCN 2018021374 . Further reading [ edit ] Ardrey, Robert . 1970. The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder . Atheneum . ISBN 0689103476 . Sapolsky, Robert M. (2017). Behave: The Biology of Humans at Our Best and Worst . Penguin Press. ISBN 978-1594205071 . External links [ edit ] Wikiquote has quotations related to Human behavior . Media related to Human behavior at Wikimedia Commons Authority control databases International FAST National France BnF data Israel United States Japan Czech Republic Other NARA Retrieved from " https://en.wikipedia.org/w/index.php?title=Human_behavior&oldid=1215120043 " Categories : Human behavior Behavior Culture Humans Main topic articles Hidden categories: Articles with short description Short description is different from Wikidata Use American English from February 2020 All Wikipedia articles written in American English CS1: long volume value CS1 maint: DOI inactive as of January 2024 Commons category link is on Wikidata Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with J9U identifiers Articles with LCCN identifiers Articles with NDL identifiers Articles with NKC identifiers Articles with NARA identifiers
22 languages العربية বাংলা Català Deutsch Español Esperanto فارسی Français 한국어 Հայերեն हिन्दी Bahasa Indonesia עברית Қазақша Kiswahili Bahasa Melayu Slovenčina Suomi Українська اردو 粵語 中文 Edit links
العربية বাংলা Català Deutsch Español Esperanto فارسی Français 한국어 Հայերեն हिन्दी Bahasa Indonesia עברית Қазақша Kiswahili Bahasa Melayu Slovenčina Suomi Українська اردو 粵語 中文 Edit links
العربية বাংলা Català Deutsch Español Esperanto فارسی Français 한국어 Հայերեն हिन्दी Bahasa Indonesia עברית Қазақша Kiswahili Bahasa Melayu Slovenčina Suomi Українська اردو 粵語 中文 Edit links
Article Talk English Read Edit View history Tools Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote
Article Talk English Read Edit View history Tools Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote
Read Edit View history Tools Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote
Tools Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote
Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote
Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote
Tools move to sidebar hide Actions Read Edit View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikiquote
General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item
What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item
From Wikipedia, the free encyclopedia Array of every physical action and observable emotion associated with humans For the song, see Human Behaviour . Social interaction and creative expression are forms of human behavior Part of a series on Sociology History Outline Index Key themes Society Globalization Human behavior Human environmental impact Identity Industrial revolutions 3 / 4 / 5 Social complexity Social construct Social environment Social equality Social equity Social power Social stratification Social structure Perspectives Conflict theory Critical theory Structural functionalism Positivism Social constructionism Symbolic interactionism Branches Aging Architecture Art Astrosociology Body Criminology Consciousness Culture Death Demography Deviance Disaster Economic Education Emotion ( Jealousy ) Environmental Family Feminist Fiscal Food Gender Generations Health Historical Immigration Industrial Internet Jewry Knowledge Language Law Leisure Literature Marxist Mathematic Medical Military Music Peace, war, and social conflict Philosophy Political Public Punishment Race and ethnicity Religion Rural Science ( History of science ) Social movements Social psychology Sociocybernetics Sociology Space Sport Technology Terrorism Urban Utopian Victimology Visual Methods Quantitative Qualitative Comparative Computational Ethnographic Conversation analysis Historical Interview Mathematical Network analysis Social experiment Survey Sociologists 1700s: Comte · Sieyès 1800s: Martineau · Tocqueville · Marx · Spencer · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Marcuse 1900s: Fromm · Adorno · Merton · Mills · Goffman · Bauman · Foucault · Habermas · Baudrillard · Bourdieu · Giddens Lists Bibliography Terminology Journals Organizations People Timeline By country Society portal v t e Human behavior is the potential and expressed capacity ( mentally , physically , and socially ) of human individuals or groups to respond to internal and external stimuli throughout their life. Behavior is driven by genetic and environmental factors that affect an individual. Behavior is also driven, in part, by thoughts and feelings , which provide insight into individual psyche , revealing such things as attitudes and values . Human behavior is shaped by psychological traits , as personality types vary from person to person, producing different actions and behavior. Social behavior accounts for actions directed at others. It is concerned with the considerable influence of social interaction and culture , as well as ethics , interpersonal relationships , politics , and conflict . Some behaviors are common while others are unusual. The acceptability of behavior depends upon social norms and is regulated by various means of social control . Social norms also condition behavior, whereby humans are pressured into following certain rules and displaying certain behaviors that are deemed acceptable or unacceptable depending on the given society or culture. Cognitive behavior accounts for actions of obtaining and using knowledge . It is concerned with how information is learned and passed on, as well as creative application of knowledge and personal beliefs such as religion . Physiological behavior accounts for actions to maintain the body. It is concerned with basic bodily functions as well as measures taken to maintain health. Economic behavior accounts for actions regarding the development, organization, and use of materials as well as other forms of work . Ecological behavior accounts for actions involving the ecosystem. It is concerned with how humans interact with other organisms and how the environment shapes human behavior. Study [ edit ] Main article: Human ethology Human behavior is studied by the social sciences , which include psychology , sociology , ethology , and their various branches and schools of thought. There are many different facets of human behavior, and no one definition or field study encompasses it in its entirety. The nature versus nurture debate is one of the fundamental divisions in the study of human behavior; this debate considers whether behavior is predominantly affected by genetic or environmental factors. The study of human behavior sometimes receives public attention due to its intersection with cultural issues, including crime , sexuality , and social inequality . Some natural sciences also place emphasis on human behavior. Neurology and evolutionary biology , study how behavior is controlled by the nervous system and how the human mind evolved , respectively. In other fields, human behavior may be a secondary subject of study when considering how it affects another subject. Outside of formal scientific inquiry, human behavior and the human condition is also a major focus of philosophy and literature . Philosophy of mind considers aspects such as free will , the mind–body problem , and malleability of human behavior. Human behavior may be evaluated through questionnaires , interviews , and experimental methods . Animal testing may also be used to test behaviors that can then be compared to human behavior. Twin studies are a common method by which human behavior is studied. Twins with identical genomes can be compared to isolate genetic and environmental factors in behavior. Lifestyle, susceptibility to disease, and unhealthy behaviors have been identified to have both genetic and environmental indicators through twin studies. Social behavior [ edit ] Further information: Sociology Women bowing in Japan ( c. 1880 ) Human social behavior is the behavior that considers other humans, including communication and cooperation. It is highly complex and structured, based on advanced theory of mind that allows humans to attribute thoughts and actions to one another. Through social behavior, humans have developed society and culture distinct from other animals. Human social behavior is governed by a combination of biological factors that affect all humans and cultural factors that change depending on upbringing and societal norms. Human communication is based heavily on language , typically through speech or writing . Nonverbal communication and paralanguage can modify the meaning of communications by demonstrating ideas and intent through physical and vocal behaviors. Social norms [ edit ] Human behavior in a society is governed by social norms . Social norms are unwritten expectations that members of society have for one another. These norms are ingrained in the particular culture that they emerge from, and humans often follow them unconsciously or without deliberation. These norms affect every aspect of life in human society, including decorum , social responsibility , property rights , contractual agreement , morality , justice , and meaning . Many norms facilitate coordination between members of society and prove mutually beneficial, such as norms regarding communication and agreements. Norms are enforced by social pressure , and individuals that violate social norms risk social exclusion . Systems of ethics are used to guide human behavior to determine what is moral. Humans are distinct from other animals in the use of ethical systems to determine behavior. Ethical behavior is human behavior that takes into consideration how actions will affect others and whether behaviors will be optimal for others. What constitutes ethical behavior is determined by the individual value judgments of the person and the collective social norms regarding right and wrong. Value judgments are intrinsic to people of all cultures, though the specific systems used to evaluate them may vary. These systems may be derived from divine law , natural law , civil authority , reason , or a combination of these and other principles. Altruism is an associated behavior in which humans consider the welfare of others equally or preferentially to their own. While other animals engage in biological altruism, ethical altruism is unique to humans. Deviance is behavior that violates social norms. As social norms vary between individuals and cultures, the nature and severity of a deviant act is subjective. What is considered deviant by a society may also change over time as new social norms are developed. Deviance is punished by other individuals through social stigma , censure , or violence . Many deviant actions are recognized as crimes and punished through a system of criminal justice . Deviant actions may be punished to prevent harm to others, to maintain a particular worldview and way of life, or to enforce principles of morality and decency . Cultures also attribute positive or negative value to certain physical traits, causing individuals that do not have desirable traits to be seen as deviant. Interpersonal relationships [ edit ] Main article: Interpersonal relationship A family in Noatak , Alaska (1929) Interpersonal relationships can be evaluated by the specific choices and emotions between two individuals, or they can be evaluated by the broader societal context of how such a relationship is expected to function. Relationships are developed through communication, which creates intimacy, expresses emotions, and develops identity. An individual's interpersonal relationships form a social group in which individuals all communicate and socialize with one another, and these social groups are connected by additional relationships. Human social behavior is affected not only by individual relationships, but also by how behaviors in one relationship may affect others. Individuals that actively seek out social interactions are extraverts , and those that do not are introverts. Romantic love is a significant interpersonal attraction toward another. Its nature varies by culture, but it is often contingent on gender, occurring in conjunction with sexual attraction and being either heterosexual or homosexual . It takes different forms and is associated with many individual emotions. Many cultures place a higher emphasis on romantic love than other forms of interpersonal attraction. Marriage is a union between two people, though whether it is associated with romantic love is dependent on the culture. Individuals that are closely related by consanguinity form a family . There are many variations on family structures that may include parents and children as well as stepchildren or extended relatives. Family units with children emphasize parenting , in which parents engage in a high level of parental investment to protect and instruct children as they develop over a period of time longer than that of most other mammals. Politics and conflict [ edit ] Further information: Political science , Theories of political behavior , and Conflict (process) A depiction of men fighting in the First Battle of Komárom (1849) When humans make decisions as a group, they engage in politics. Humans have evolved to engage in behaviors of self-interest , but this also includes behaviors that facilitate cooperation rather than conflict in collective settings. Individuals will often form in-group and out-group perceptions, through which individuals cooperate with the in-group and compete with the out-group. This causes behaviors such as unconsciously conforming, passively obeying authority, taking pleasure in the misfortune of opponents, initiating hostility toward out-group members, artificially creating out-groups when none exist, and punishing those that do not comply with the standards of the in-group. These behaviors lead to the creation of political systems that enforce in-group standards and norms. When humans oppose one another, it creates conflict. It may occur when the involved parties have a disagreement of opinion, when one party obstructs the goals of another, or when parties experience negative emotions such as anger toward one another. Conflicts purely of disagreement are often resolved through communication or negotiation , but incorporation of emotional or obstructive aspects can escalate conflict. Interpersonal conflict is that between specific individuals or groups of individuals. Social conflict is that between different social groups or demographics. This form of conflict often takes place when groups in society are marginalized, do not have the resources they desire, wish to instigate social change, or wish to resist social change. Significant social conflict can cause civil disorder . International conflict is that between nations or governments. It may be solved through diplomacy or war . Cognitive behavior [ edit ] Main article: Cognition People being taught to paint in Volgograd , Russia (2013) Human cognition is distinct from that of other animals. This is derived from biological traits of human cognition, but also from shared knowledge and development passed down culturally. Humans are able to learn from one another due to advanced theory of mind that allows knowledge to be obtained through education . The use of language allows humans to directly pass knowledge to one another. The human brain has neuroplasticity , allowing it to modify its features in response to new experiences. This facilitates learning in humans and leads to behaviors of practice , allowing the development of new skills in individual humans. Behavior carried out over time can be ingrained as a habit , where humans will continue to regularly engage in the behavior without consciously deciding to do so. Humans engage in reason to make inferences with a limited amount of information. Most human reasoning is done automatically without conscious effort on the part of the individual. Reasoning is carried out by making generalizations from past experiences and applying them to new circumstances. Learned knowledge is acquired to make more accurate inferences about the subject. Deductive reasoning infers conclusions that are true based on logical premises, while inductive reasoning infers what conclusions are likely to be true based on context. Emotion is a cognitive experience innate to humans. Basic emotions such as joy , distress , anger , fear , surprise , and disgust are common to all cultures, though social norms regarding the expression of emotion may vary. Other emotions come from higher cognition, such as love , guilt , shame , embarrassment , pride , envy , and jealousy . These emotions develop over time rather than instantly and are more strongly influenced by cultural factors. Emotions are influenced by sensory information , such as color and music , and moods of happiness and sadness . Humans typically maintain a standard level of happiness or sadness determined by health and social relationships, though positive and negative events have short-term influences on mood. Humans often seek to improve the moods of one another through consolation , entertainment , and venting . Humans can also self-regulate mood through exercise and meditation . Creativity is the use of previous ideas or resources to produce something original. It allows for innovation , adaptation to change, learning new information, and novel problem solving. Expression of creativity also supports quality of life . Creativity includes personal creativity, in which a person presents new ideas authentically , but it can also be expanded to social creativity, in which a community or society produces and recognizes ideas collectively. Creativity is applied in typical human life to solve problems as they occur. It also leads humans to carry out art and science . Individuals engaging in advanced creative work typically have specialized knowledge in that field, and humans draw on this knowledge to develop novel ideas. In art, creativity is used to develop new artistic works, such as visual art or music . In science, those with knowledge in a particular scientific field can use trial and error to develop theories that more accurately explain phenomena. Religious behavior is a set of traditions that are followed based on the teachings of a religious belief system. The nature of religious behavior varies depending on the specific religious traditions. Most religious traditions involve variations of telling myths , practicing rituals , making certain things taboo , adopting symbolism , determining morality, experiencing altered states of consciousness , and believing in supernatural beings. Religious behavior is often demanding and has high time, energy, and material costs, and it conflicts with rational choice models of human behavior, though it does provide community-related benefits. Anthropologists offer competing theories as to why humans adopted religious behavior. Religious behavior is heavily influenced by social factors, and group involvement is significant in the development of an individual's religious behavior. Social structures such as religious organizations or family units allow the sharing and coordination of religious behavior. These social connections reinforce the cognitive behaviors associated with religion, encouraging orthodoxy and commitment. According to a Pew Research Center report, 54% of adults around the world state that religion is very important in their lives as of 2018. Physiological behavior [ edit ] See also: Psychophysiology A boy eating in Harare , Zimbabwe (2017) Humans undergo many behaviors common to animals to support the processes of the human body . Humans eat food to obtain nutrition . These foods may be chosen for their nutritional value, but they may also be eaten for pleasure . Eating often follows a food preparation process to make it more enjoyable. Humans dispose of excess food through waste . Excrement is often treated as taboo, particularly in developed and urban communities where sanitation is more widely available and excrement has no value as fertilizer . Humans also regularly engage in sleep , based on homeostatic and circadian factors. The circadian rhythm causes humans to require sleep at a regular pattern and is typically calibrated to the day-night cycle and sleep-wake habits. Homeostasis is also be maintained, causing longer sleep longer after periods of sleep deprivation . The human sleep cycle takes place over 90 minutes, and it repeats 3–5 times during normal sleep. There are also unique behaviors that humans undergo to maintain physical health. Humans have developed medicine to prevent and treat illnesses. In industrialized nations, eating habits that favor better nutrition, hygienic behaviors that promote sanitation , medical treatment to eradicate diseases, and the use of birth control significantly improve human health. Humans can also engage in exercise beyond that required for survival to maintain health. Humans engage in hygiene to limit exposure to dirt and pathogens . Some of these behaviors are adaptive while others are learned. Basic behaviors of disgust evolved as an adaptation to prevent contact with sources of pathogens, resulting in a biological aversion to feces , body fluids , rotten food , and animals that are commonly disease vectors . Personal grooming , disposal of human corpses , use of sewerage , and use of cleaning agents are hygienic behaviors common to most human societies. Humans reproduce sexually , engaging in sexual intercourse for both reproduction and sexual pleasure . Human reproduction is closely associated with human sexuality and an instinctive desire to procreate , though humans are unique in that they intentionally control the number of offspring that they produce. Humans engage in a large variety of reproductive behaviors relative to other animals, with various mating structures that include forms of monogamy , polygyny , and polyandry . How humans engage in mating behavior is heavily influenced by cultural norms and customs. Unlike most mammals, human women ovulate spontaneously rather than seasonally, with a menstrual cycle that typically lasts 25–35 days. Humans are bipedal and move by walking . Human walking corresponds to the bipedal gait cycle , which involves alternating heel contact and toe off with the ground and slight elevation and rotation of the pelvis . Balance while walking learned during the first 7–9 years of life, and individual humans develop unique gaits while learning to displace weight, adjust center of mass , and correspond neural control with movement. Humans can achieve higher speed by running . The endurance running hypothesis proposes that humans can outpace most other animals over long distances through running, though human running causes a higher rate of energy exertion. The human body self-regulates through perspiration during periods of exertion, allowing humans more endurance than other animals. The human hand is prehensile and capable of grasping objects and applying force with control over the hand's dexterity and grip strength . This allows the use of complex tools by humans. Economic behavior [ edit ] Further information: Behavioral economics Humans engage in predictable behaviors when considering economic decisions, and these behaviors may or may not be rational . Like all animals, humans make basic decisions through cost–benefit analysis and the risk–return spectrum , though humans are able to contemplate these decisions more thoroughly. Human economic decision making is often reference dependent , in which options are weighed in reference to the status quo rather than absolute gains and losses. Humans are also loss averse , fearing loss rather than seeking gain. Advanced economic behavior developed in humans after the Neolithic Revolution and the development of agriculture . These developments led to a sustainable supply of resources that allowed specialization in more complex societies. Work [ edit ] Main article: Work (human activity) Women tending to farm animals in Mangskogs, Sweden (1911) The nature of human work is defined by the complexity of society. The simplest societies are tribes that work primarily for sustenance as hunter-gatherers . In this sense, work is not a distinct activity but a constant that makes up all parts of life, as all members of the society must work consistently to stay alive. More advanced societies developed after the Neolithic Revolution, emphasizing work in agricultural and pastoral settings. In these societies, production is increased, ending the need for constant work and allowing some individuals to specialize and work in areas outside of food-production. This also created non-laborious work, as increasing occupational complexity required some individuals to specialize in technical knowledge and administration. Laborious work in these societies has variously been carried out by slaves, serfs, peasants, and guild craftsmen. The nature of work changed significantly during the Industrial Revolution in which the factory system was developed for use by industrializing nations. In addition to further increasing general quality of life, this development changed the dynamic of work. Under the factory system, workers increasingly collaborate with others, employers serve as authority figures during work hours, and forced labor is largely eradicated. Further changes occur in post-industrial societies where technological advance makes industries obsolete, replacing them with mass production and service industries . Humans approach work differently based on both physical and personal attributes, and some work with more effectiveness and commitment than others. Some find work to contribute to personal fulfillment, while others work only out of necessity. Work can also serve as an identity, with individuals identifying themselves based on their occupation. Work motivation is complex, both contributing to and subtracting from various human needs. The primary motivation for work is for material gain, which takes the form of money in modern societies. It may also serve to create self-esteem and personal worth, provide activity, gain respect, and express creativity. Modern work is typically categorized as laborious or blue-collar work and non-laborious or white-collar work . Leisure [ edit ] Main article: Leisure Men playing association football in Kilkenny , Ireland (2007) Leisure is activity or lack of activity that takes place outside of work. It provides relaxation, entertainment , and improved quality of life for individuals. Engaging in leisure can be beneficial for physical and mental health. It may be used to seek temporary relief from psychological stress , to produce positive emotions, or to facilitate social interaction. Leisure can also facilitate health risks and negative emotions caused by boredom , substance abuse , or high-risk behavior . Leisure may be defined as serious or casual. Serious leisure behaviors involve non-professional pursuit of arts and sciences, the development of hobbies , or career volunteering in an area of expertise. Casual leisure behaviors provide short-term gratification, but they do not provide long-term gratification or personal identity. These include play , relaxation, casual social interaction, volunteering , passive entertainment, active entertainment, and sensory stimulation. Passive entertainment is typically derived from mass media , which may include written works or digital media . Active entertainment involves games in which individuals participate. Sensory stimulation is immediate gratification from behaviors such as eating or sexual intercourse. Consumption [ edit ] Main article: Consumer behaviour Humans operate as consumers that obtain and use goods. All production is ultimately designed for consumption , and consumers adapt their behavior based on the availability of production. Mass consumption began during the Industrial Revolution, caused by the development of new technologies that allowed for increased production. Many factors affect a consumer's decision to purchase goods through trade. They may consider the nature of the product, its associated cost, the convenience of purchase, and the nature of advertising around the product. Cultural factors may influence this decision, as different cultures value different things, and subcultures within these cultures may have distinct priorities as buyers. Social class , including wealth, education, and occupation may affect one's purchasing behavior. A consumer's interpersonal relationships and reference groups may also influence purchasing behavior. Ecological behavior [ edit ] Main article: Human ecology A girl with lambs in Gilandeh , Iran (2018) Like all living things, humans live in ecosystems and interact with other organisms. Human behavior is affected by the environment in which a human lives, and environments are affected by human habitation. Humans have also developed man-made ecosystems such as urban areas and agricultural land . Geography and landscape ecology determine how humans are distributed within an ecosystem, both naturally and through planned urban morphology . Humans exercise control over the animals that live within their environment. Domesticated animals are trained and cared for by humans. Humans can develop social and emotional bonds with animals in their care. Pets are kept for companionship within human homes, including dogs and cats that have been bred for domestication over many centuries. Livestock animals, such as cattle , sheep , goats , and poultry , are kept on agricultural land to produce animal products . Domesticated animals are also kept in laboratories for animal testing . Non-domesticated animals are sometimes kept in nature reserves and zoos for tourism and conservation . Causes and factors [ edit ] Human behavior is influenced by biological and cultural elements. The structure and agency debate considers whether human behavior is predominantly led by individual human impulses or by external structural forces. Behavioral genetics considers how human behavior is affected by inherited traits. Though genes do not guarantee certain behaviors, certain traits can be inherited that make individuals more likely to engage in certain behaviors or express certain personalities. An individual's environment can also affect behavior, often in conjunction with genetic factors. An individual's personality and attitudes affect how behaviors are expressed, formed in conjunction by genetic and environmental factors. Age [ edit ] Further information: Ageing An infant engaging in play in Los Angeles , California (2015) Infants are limited in their ability to interpret their surroundings shortly after birth. Object permanence and understanding of motion typically develop within the first six months of an infant's life, though the specific cognitive processes are not understood. The ability to mentally categorize different concepts and objects that they perceive also develops within the first year. Infants are quickly able to discern their body from their surroundings and often take interest in their own limbs or actions they cause by two months of age. Infants practice imitation of other individuals to engage socially and learn new behaviors. In young infants, this involves imitating facial expressions , and imitation of tool use takes place within the first year. Communication develops over the first year, and infants begin using gestures to communicate intention around nine to ten months of age. Verbal communication develops more gradually, taking form during the second year of age. Children develop fine motor skills shortly after infancy, in the range of three to six years of age, allowing them to engage in behaviors using the hands and eye–hand coordination and perform basic activities of self sufficiency . Children begin expressing more complex emotions in the three- to six-year-old range, including humor, empathy, and altruism, as well engaging in creativity and inquiry. Aggressive behaviors also become varied at this age as children engage in increased physical aggression before learning to favor diplomacy over aggression. Children at this age can express themselves using language with basic grammar. As children grow older, they develop emotional intelligence . Young children engage in basic social behaviors with peers , typically forming friendships centered on play with individuals of the same age and gender. Behaviors of young children are centered around play, which allows them to practice physical, cognitive, and social behaviors. Basic self-concept first develops as children grow, particularly centered around traits such as gender and ethnicity, and behavior is heavily affected by peers for the first time. Adolescents undergo changes in behavior caused by puberty and the associated changes in hormone production. Production of testosterone increases sensation seeking and sensitivity to rewards in adolescents as well as aggression and risk-taking in adolescent boys. Production of estradiol causes similar risk-taking behavior among adolescent girls. The new hormones cause changes in emotional processing that allow for close friendships, stronger motivations and intentions, and adolescent sexuality . Adolescents undergo social changes on a large scale, developing a full self-concept and making autonomous decisions independently of adults. They typically become more aware of social norms and social cues than children, causing an increase in self-consciousness and adolescent egocentrism that guides behavior in social settings throughout adolescence. Culture and environment [ edit ] Human brains, as with those of all mammals, are neuroplastic . This means that the structure of the brain changes over time as neural pathways are altered in response to the environment. Many behaviors are learned through interaction with others during early development of the brain. Human behavior is distinct from the behavior of other animals in that it is heavily influenced by culture and language. Social learning allows humans to develop new behaviors by following the example of others. Culture is also the guiding influence that defines social norms. Genetics [ edit ] Physiology [ edit ] Neurotransmitters , hormones , and metabolism are all recognized as biological factors in human behavior. Physical disabilities can prevent individuals from engaging in typical human behavior or necessitate alternative behaviors. Accommodations and accessibility are often made available for individuals with physical disabilities in developed nations, including health care, assistive technology , and vocational services . Severe disabilities are associated with increased leisure time but also with a lower satisfaction in the quality of leisure time. Productivity and health both commonly undergo long term decline following the onset of a severe disability. Mental disabilities are those that directly affect cognitive and social behavior. Common mental disorders include mood disorders , anxiety disorders , personality disorders , and substance dependence . See also [ edit ] Psychology portal Society portal Behavioral modernity Behaviorism Cultural ecology Human behavioral ecology References [ edit ] ^ Longino 2013 , pp. 13–14. ^ Longino 2013 , pp. 7–8. ^ Longino 2013 , p. 2. ^ Longino 2013 , p. 11. ^ Longino 2013 , p. 1. ^ Longino 2013 , p. 8. ^ Longino 2013 , pp. 9–10. ^ Longino 2013 , p. 12. ^ Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 . ^ Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 . ^ Duck 2007 , pp. 1–5. ^ Duck 2007 , pp. 10–14. ^ Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 . ^ Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 . ^ Goode 2015 , pp. 3–4. ^ Goode 2015 , p. 7. ^ Goode 2015 , p. 5. ^ Goode 2015 , p. 6. ^ Duck 2007 , p. 107. ^ Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 . ^ Duck 2007 , pp. 56–60. ^ Duck 2007 , pp. 121–125. ^ Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 . ^ Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 . ^ Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 . ^ Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation. ^ Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 . ^ Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 . ^ Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 . ^ Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 . ^ Evans 2003 , pp. 1–21. ^ Evans 2003 , pp. 47–. ^ Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 . ^ Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 . ^ " 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 . ^ Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 . ^ Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 . ^ Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 . ^ McKeown, Thomas (1980). The Role of Medicine . Princeton University Press. p. 78. ISBN 978-1400854622 . ^ Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 . ^ Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 . ^ Baggott, L. M. (1997). Human Reproduction . Cambridge University Press. p. 5. ISBN 978-0521469142 . ^ Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 . ^ Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 . ^ Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 . ^ Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 . ^ Neff 1985 , pp. 24–33. ^ Neff 1985 , pp. 41–46. ^ Neff 1985 , p. 2. ^ Neff 1985 , pp. 142–153. ^ Neff 1985 , pp. 79–80. ^ Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 . ^ Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 . ^ Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X . ^ Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 . ^ Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 . ^ Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 . ^ Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 . ^ Bremner & Wachs 2010 , pp. 234–235. ^ Bremner & Wachs 2010 , pp. 264–265. ^ Bremner & Wachs 2010 , pp. 337–340. ^ Bremner & Wachs 2010 , pp. 346–347. ^ Bremner & Wachs 2010 , pp. 398–399. ^ Woody & Woody 2019 , pp. 259–260. ^ Woody & Woody 2019 , p. 263. ^ Woody & Woody 2019 , p. 279. ^ Woody & Woody 2019 , pp. 268–269. ^ Charlesworth 2019 , p. 346. ^ Woody & Woody 2019 , p. 281. ^ Woody & Woody 2019 , p. 290. ^ Charlesworth 2019 , p. 343. ^ Charlesworth 2019 , p. 353. ^ Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 . ^ Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 . ^ Van Schaik 2016 , Chapter 2.4. ^ Van Schaik 2016 , Chapter 3.1. ^ Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 . ^ Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 . ^ Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 . Bibliography [ edit ] Bremner, Gavin; Wachs, Theodore D., eds. (2010). The Wiley-Blackwell Handbook of Infant Development . Vol. 1: Basic Research (2nd ed.). Wiley-Blackwell. ISBN 978-1444332735 . Charlesworth, Leanne Wood (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 327–395. ISBN 978-1544339344 . LCCN 2018021374 . Duck, Steve (2007). Human Relationships (4th ed.). SAGE Publications. ISBN 978-1412929998 . Evans, Dylan (2003). Emotion: A Very Short Introduction . Oxford University Press. ISBN 978-0192804617 . Goode, Erich (2015). "The Sociology of Deviance: An Introduction". In Goode, Erich (ed.). The Handbook of Deviance . Wiley. pp. 3–29. doi : 10.1002/9781118701386 . ISBN 978-1118701324 . Longino, Helen E. (2013). Studying Human Behavior: How Scientists Investigate Aggression and Sexuality . University of Chicago Press. doi : 10.7208/9780226921822 (inactive 31 January 2024). ISBN 978-0226921822 . {{ cite book }} : CS1 maint: DOI inactive as of January 2024 ( link ) Neff, Walter S. (1985). Work and Human Behavior (3rd ed.). Aldine Publishing Company. ISBN 0202303195 . Van Schaik, Carel P. (2016). The primate origins of human nature . Foundations of human biology. Hoboken, New Jersey: Wiley-Blackwell. ISBN 978-1-119-11820-6 . Woody, Debra J.; Woody, David (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 251–326. ISBN 978-1544339344 . LCCN 2018021374 . Further reading [ edit ] Ardrey, Robert . 1970. The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder . Atheneum . ISBN 0689103476 . Sapolsky, Robert M. (2017). Behave: The Biology of Humans at Our Best and Worst . Penguin Press. ISBN 978-1594205071 . External links [ edit ] Wikiquote has quotations related to Human behavior . Media related to Human behavior at Wikimedia Commons Authority control databases International FAST National France BnF data Israel United States Japan Czech Republic Other NARA Retrieved from " https://en.wikipedia.org/w/index.php?title=Human_behavior&oldid=1215120043 " Categories : Human behavior Behavior Culture Humans Main topic articles Hidden categories: Articles with short description Short description is different from Wikidata Use American English from February 2020 All Wikipedia articles written in American English CS1: long volume value CS1 maint: DOI inactive as of January 2024 Commons category link is on Wikidata Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with J9U identifiers Articles with LCCN identifiers Articles with NDL identifiers Articles with NKC identifiers Articles with NARA identifiers
Array of every physical action and observable emotion associated with humans For the song, see Human Behaviour . Social interaction and creative expression are forms of human behavior Part of a series on Sociology History Outline Index Key themes Society Globalization Human behavior Human environmental impact Identity Industrial revolutions 3 / 4 / 5 Social complexity Social construct Social environment Social equality Social equity Social power Social stratification Social structure Perspectives Conflict theory Critical theory Structural functionalism Positivism Social constructionism Symbolic interactionism Branches Aging Architecture Art Astrosociology Body Criminology Consciousness Culture Death Demography Deviance Disaster Economic Education Emotion ( Jealousy ) Environmental Family Feminist Fiscal Food Gender Generations Health Historical Immigration Industrial Internet Jewry Knowledge Language Law Leisure Literature Marxist Mathematic Medical Military Music Peace, war, and social conflict Philosophy Political Public Punishment Race and ethnicity Religion Rural Science ( History of science ) Social movements Social psychology Sociocybernetics Sociology Space Sport Technology Terrorism Urban Utopian Victimology Visual Methods Quantitative Qualitative Comparative Computational Ethnographic Conversation analysis Historical Interview Mathematical Network analysis Social experiment Survey Sociologists 1700s: Comte · Sieyès 1800s: Martineau · Tocqueville · Marx · Spencer · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Marcuse 1900s: Fromm · Adorno · Merton · Mills · Goffman · Bauman · Foucault · Habermas · Baudrillard · Bourdieu · Giddens Lists Bibliography Terminology Journals Organizations People Timeline By country Society portal v t e Human behavior is the potential and expressed capacity ( mentally , physically , and socially ) of human individuals or groups to respond to internal and external stimuli throughout their life. Behavior is driven by genetic and environmental factors that affect an individual. Behavior is also driven, in part, by thoughts and feelings , which provide insight into individual psyche , revealing such things as attitudes and values . Human behavior is shaped by psychological traits , as personality types vary from person to person, producing different actions and behavior. Social behavior accounts for actions directed at others. It is concerned with the considerable influence of social interaction and culture , as well as ethics , interpersonal relationships , politics , and conflict . Some behaviors are common while others are unusual. The acceptability of behavior depends upon social norms and is regulated by various means of social control . Social norms also condition behavior, whereby humans are pressured into following certain rules and displaying certain behaviors that are deemed acceptable or unacceptable depending on the given society or culture. Cognitive behavior accounts for actions of obtaining and using knowledge . It is concerned with how information is learned and passed on, as well as creative application of knowledge and personal beliefs such as religion . Physiological behavior accounts for actions to maintain the body. It is concerned with basic bodily functions as well as measures taken to maintain health. Economic behavior accounts for actions regarding the development, organization, and use of materials as well as other forms of work . Ecological behavior accounts for actions involving the ecosystem. It is concerned with how humans interact with other organisms and how the environment shapes human behavior. Study [ edit ] Main article: Human ethology Human behavior is studied by the social sciences , which include psychology , sociology , ethology , and their various branches and schools of thought. There are many different facets of human behavior, and no one definition or field study encompasses it in its entirety. The nature versus nurture debate is one of the fundamental divisions in the study of human behavior; this debate considers whether behavior is predominantly affected by genetic or environmental factors. The study of human behavior sometimes receives public attention due to its intersection with cultural issues, including crime , sexuality , and social inequality . Some natural sciences also place emphasis on human behavior. Neurology and evolutionary biology , study how behavior is controlled by the nervous system and how the human mind evolved , respectively. In other fields, human behavior may be a secondary subject of study when considering how it affects another subject. Outside of formal scientific inquiry, human behavior and the human condition is also a major focus of philosophy and literature . Philosophy of mind considers aspects such as free will , the mind–body problem , and malleability of human behavior. Human behavior may be evaluated through questionnaires , interviews , and experimental methods . Animal testing may also be used to test behaviors that can then be compared to human behavior. Twin studies are a common method by which human behavior is studied. Twins with identical genomes can be compared to isolate genetic and environmental factors in behavior. Lifestyle, susceptibility to disease, and unhealthy behaviors have been identified to have both genetic and environmental indicators through twin studies. Social behavior [ edit ] Further information: Sociology Women bowing in Japan ( c. 1880 ) Human social behavior is the behavior that considers other humans, including communication and cooperation. It is highly complex and structured, based on advanced theory of mind that allows humans to attribute thoughts and actions to one another. Through social behavior, humans have developed society and culture distinct from other animals. Human social behavior is governed by a combination of biological factors that affect all humans and cultural factors that change depending on upbringing and societal norms. Human communication is based heavily on language , typically through speech or writing . Nonverbal communication and paralanguage can modify the meaning of communications by demonstrating ideas and intent through physical and vocal behaviors. Social norms [ edit ] Human behavior in a society is governed by social norms . Social norms are unwritten expectations that members of society have for one another. These norms are ingrained in the particular culture that they emerge from, and humans often follow them unconsciously or without deliberation. These norms affect every aspect of life in human society, including decorum , social responsibility , property rights , contractual agreement , morality , justice , and meaning . Many norms facilitate coordination between members of society and prove mutually beneficial, such as norms regarding communication and agreements. Norms are enforced by social pressure , and individuals that violate social norms risk social exclusion . Systems of ethics are used to guide human behavior to determine what is moral. Humans are distinct from other animals in the use of ethical systems to determine behavior. Ethical behavior is human behavior that takes into consideration how actions will affect others and whether behaviors will be optimal for others. What constitutes ethical behavior is determined by the individual value judgments of the person and the collective social norms regarding right and wrong. Value judgments are intrinsic to people of all cultures, though the specific systems used to evaluate them may vary. These systems may be derived from divine law , natural law , civil authority , reason , or a combination of these and other principles. Altruism is an associated behavior in which humans consider the welfare of others equally or preferentially to their own. While other animals engage in biological altruism, ethical altruism is unique to humans. Deviance is behavior that violates social norms. As social norms vary between individuals and cultures, the nature and severity of a deviant act is subjective. What is considered deviant by a society may also change over time as new social norms are developed. Deviance is punished by other individuals through social stigma , censure , or violence . Many deviant actions are recognized as crimes and punished through a system of criminal justice . Deviant actions may be punished to prevent harm to others, to maintain a particular worldview and way of life, or to enforce principles of morality and decency . Cultures also attribute positive or negative value to certain physical traits, causing individuals that do not have desirable traits to be seen as deviant. Interpersonal relationships [ edit ] Main article: Interpersonal relationship A family in Noatak , Alaska (1929) Interpersonal relationships can be evaluated by the specific choices and emotions between two individuals, or they can be evaluated by the broader societal context of how such a relationship is expected to function. Relationships are developed through communication, which creates intimacy, expresses emotions, and develops identity. An individual's interpersonal relationships form a social group in which individuals all communicate and socialize with one another, and these social groups are connected by additional relationships. Human social behavior is affected not only by individual relationships, but also by how behaviors in one relationship may affect others. Individuals that actively seek out social interactions are extraverts , and those that do not are introverts. Romantic love is a significant interpersonal attraction toward another. Its nature varies by culture, but it is often contingent on gender, occurring in conjunction with sexual attraction and being either heterosexual or homosexual . It takes different forms and is associated with many individual emotions. Many cultures place a higher emphasis on romantic love than other forms of interpersonal attraction. Marriage is a union between two people, though whether it is associated with romantic love is dependent on the culture. Individuals that are closely related by consanguinity form a family . There are many variations on family structures that may include parents and children as well as stepchildren or extended relatives. Family units with children emphasize parenting , in which parents engage in a high level of parental investment to protect and instruct children as they develop over a period of time longer than that of most other mammals. Politics and conflict [ edit ] Further information: Political science , Theories of political behavior , and Conflict (process) A depiction of men fighting in the First Battle of Komárom (1849) When humans make decisions as a group, they engage in politics. Humans have evolved to engage in behaviors of self-interest , but this also includes behaviors that facilitate cooperation rather than conflict in collective settings. Individuals will often form in-group and out-group perceptions, through which individuals cooperate with the in-group and compete with the out-group. This causes behaviors such as unconsciously conforming, passively obeying authority, taking pleasure in the misfortune of opponents, initiating hostility toward out-group members, artificially creating out-groups when none exist, and punishing those that do not comply with the standards of the in-group. These behaviors lead to the creation of political systems that enforce in-group standards and norms. When humans oppose one another, it creates conflict. It may occur when the involved parties have a disagreement of opinion, when one party obstructs the goals of another, or when parties experience negative emotions such as anger toward one another. Conflicts purely of disagreement are often resolved through communication or negotiation , but incorporation of emotional or obstructive aspects can escalate conflict. Interpersonal conflict is that between specific individuals or groups of individuals. Social conflict is that between different social groups or demographics. This form of conflict often takes place when groups in society are marginalized, do not have the resources they desire, wish to instigate social change, or wish to resist social change. Significant social conflict can cause civil disorder . International conflict is that between nations or governments. It may be solved through diplomacy or war . Cognitive behavior [ edit ] Main article: Cognition People being taught to paint in Volgograd , Russia (2013) Human cognition is distinct from that of other animals. This is derived from biological traits of human cognition, but also from shared knowledge and development passed down culturally. Humans are able to learn from one another due to advanced theory of mind that allows knowledge to be obtained through education . The use of language allows humans to directly pass knowledge to one another. The human brain has neuroplasticity , allowing it to modify its features in response to new experiences. This facilitates learning in humans and leads to behaviors of practice , allowing the development of new skills in individual humans. Behavior carried out over time can be ingrained as a habit , where humans will continue to regularly engage in the behavior without consciously deciding to do so. Humans engage in reason to make inferences with a limited amount of information. Most human reasoning is done automatically without conscious effort on the part of the individual. Reasoning is carried out by making generalizations from past experiences and applying them to new circumstances. Learned knowledge is acquired to make more accurate inferences about the subject. Deductive reasoning infers conclusions that are true based on logical premises, while inductive reasoning infers what conclusions are likely to be true based on context. Emotion is a cognitive experience innate to humans. Basic emotions such as joy , distress , anger , fear , surprise , and disgust are common to all cultures, though social norms regarding the expression of emotion may vary. Other emotions come from higher cognition, such as love , guilt , shame , embarrassment , pride , envy , and jealousy . These emotions develop over time rather than instantly and are more strongly influenced by cultural factors. Emotions are influenced by sensory information , such as color and music , and moods of happiness and sadness . Humans typically maintain a standard level of happiness or sadness determined by health and social relationships, though positive and negative events have short-term influences on mood. Humans often seek to improve the moods of one another through consolation , entertainment , and venting . Humans can also self-regulate mood through exercise and meditation . Creativity is the use of previous ideas or resources to produce something original. It allows for innovation , adaptation to change, learning new information, and novel problem solving. Expression of creativity also supports quality of life . Creativity includes personal creativity, in which a person presents new ideas authentically , but it can also be expanded to social creativity, in which a community or society produces and recognizes ideas collectively. Creativity is applied in typical human life to solve problems as they occur. It also leads humans to carry out art and science . Individuals engaging in advanced creative work typically have specialized knowledge in that field, and humans draw on this knowledge to develop novel ideas. In art, creativity is used to develop new artistic works, such as visual art or music . In science, those with knowledge in a particular scientific field can use trial and error to develop theories that more accurately explain phenomena. Religious behavior is a set of traditions that are followed based on the teachings of a religious belief system. The nature of religious behavior varies depending on the specific religious traditions. Most religious traditions involve variations of telling myths , practicing rituals , making certain things taboo , adopting symbolism , determining morality, experiencing altered states of consciousness , and believing in supernatural beings. Religious behavior is often demanding and has high time, energy, and material costs, and it conflicts with rational choice models of human behavior, though it does provide community-related benefits. Anthropologists offer competing theories as to why humans adopted religious behavior. Religious behavior is heavily influenced by social factors, and group involvement is significant in the development of an individual's religious behavior. Social structures such as religious organizations or family units allow the sharing and coordination of religious behavior. These social connections reinforce the cognitive behaviors associated with religion, encouraging orthodoxy and commitment. According to a Pew Research Center report, 54% of adults around the world state that religion is very important in their lives as of 2018. Physiological behavior [ edit ] See also: Psychophysiology A boy eating in Harare , Zimbabwe (2017) Humans undergo many behaviors common to animals to support the processes of the human body . Humans eat food to obtain nutrition . These foods may be chosen for their nutritional value, but they may also be eaten for pleasure . Eating often follows a food preparation process to make it more enjoyable. Humans dispose of excess food through waste . Excrement is often treated as taboo, particularly in developed and urban communities where sanitation is more widely available and excrement has no value as fertilizer . Humans also regularly engage in sleep , based on homeostatic and circadian factors. The circadian rhythm causes humans to require sleep at a regular pattern and is typically calibrated to the day-night cycle and sleep-wake habits. Homeostasis is also be maintained, causing longer sleep longer after periods of sleep deprivation . The human sleep cycle takes place over 90 minutes, and it repeats 3–5 times during normal sleep. There are also unique behaviors that humans undergo to maintain physical health. Humans have developed medicine to prevent and treat illnesses. In industrialized nations, eating habits that favor better nutrition, hygienic behaviors that promote sanitation , medical treatment to eradicate diseases, and the use of birth control significantly improve human health. Humans can also engage in exercise beyond that required for survival to maintain health. Humans engage in hygiene to limit exposure to dirt and pathogens . Some of these behaviors are adaptive while others are learned. Basic behaviors of disgust evolved as an adaptation to prevent contact with sources of pathogens, resulting in a biological aversion to feces , body fluids , rotten food , and animals that are commonly disease vectors . Personal grooming , disposal of human corpses , use of sewerage , and use of cleaning agents are hygienic behaviors common to most human societies. Humans reproduce sexually , engaging in sexual intercourse for both reproduction and sexual pleasure . Human reproduction is closely associated with human sexuality and an instinctive desire to procreate , though humans are unique in that they intentionally control the number of offspring that they produce. Humans engage in a large variety of reproductive behaviors relative to other animals, with various mating structures that include forms of monogamy , polygyny , and polyandry . How humans engage in mating behavior is heavily influenced by cultural norms and customs. Unlike most mammals, human women ovulate spontaneously rather than seasonally, with a menstrual cycle that typically lasts 25–35 days. Humans are bipedal and move by walking . Human walking corresponds to the bipedal gait cycle , which involves alternating heel contact and toe off with the ground and slight elevation and rotation of the pelvis . Balance while walking learned during the first 7–9 years of life, and individual humans develop unique gaits while learning to displace weight, adjust center of mass , and correspond neural control with movement. Humans can achieve higher speed by running . The endurance running hypothesis proposes that humans can outpace most other animals over long distances through running, though human running causes a higher rate of energy exertion. The human body self-regulates through perspiration during periods of exertion, allowing humans more endurance than other animals. The human hand is prehensile and capable of grasping objects and applying force with control over the hand's dexterity and grip strength . This allows the use of complex tools by humans. Economic behavior [ edit ] Further information: Behavioral economics Humans engage in predictable behaviors when considering economic decisions, and these behaviors may or may not be rational . Like all animals, humans make basic decisions through cost–benefit analysis and the risk–return spectrum , though humans are able to contemplate these decisions more thoroughly. Human economic decision making is often reference dependent , in which options are weighed in reference to the status quo rather than absolute gains and losses. Humans are also loss averse , fearing loss rather than seeking gain. Advanced economic behavior developed in humans after the Neolithic Revolution and the development of agriculture . These developments led to a sustainable supply of resources that allowed specialization in more complex societies. Work [ edit ] Main article: Work (human activity) Women tending to farm animals in Mangskogs, Sweden (1911) The nature of human work is defined by the complexity of society. The simplest societies are tribes that work primarily for sustenance as hunter-gatherers . In this sense, work is not a distinct activity but a constant that makes up all parts of life, as all members of the society must work consistently to stay alive. More advanced societies developed after the Neolithic Revolution, emphasizing work in agricultural and pastoral settings. In these societies, production is increased, ending the need for constant work and allowing some individuals to specialize and work in areas outside of food-production. This also created non-laborious work, as increasing occupational complexity required some individuals to specialize in technical knowledge and administration. Laborious work in these societies has variously been carried out by slaves, serfs, peasants, and guild craftsmen. The nature of work changed significantly during the Industrial Revolution in which the factory system was developed for use by industrializing nations. In addition to further increasing general quality of life, this development changed the dynamic of work. Under the factory system, workers increasingly collaborate with others, employers serve as authority figures during work hours, and forced labor is largely eradicated. Further changes occur in post-industrial societies where technological advance makes industries obsolete, replacing them with mass production and service industries . Humans approach work differently based on both physical and personal attributes, and some work with more effectiveness and commitment than others. Some find work to contribute to personal fulfillment, while others work only out of necessity. Work can also serve as an identity, with individuals identifying themselves based on their occupation. Work motivation is complex, both contributing to and subtracting from various human needs. The primary motivation for work is for material gain, which takes the form of money in modern societies. It may also serve to create self-esteem and personal worth, provide activity, gain respect, and express creativity. Modern work is typically categorized as laborious or blue-collar work and non-laborious or white-collar work . Leisure [ edit ] Main article: Leisure Men playing association football in Kilkenny , Ireland (2007) Leisure is activity or lack of activity that takes place outside of work. It provides relaxation, entertainment , and improved quality of life for individuals. Engaging in leisure can be beneficial for physical and mental health. It may be used to seek temporary relief from psychological stress , to produce positive emotions, or to facilitate social interaction. Leisure can also facilitate health risks and negative emotions caused by boredom , substance abuse , or high-risk behavior . Leisure may be defined as serious or casual. Serious leisure behaviors involve non-professional pursuit of arts and sciences, the development of hobbies , or career volunteering in an area of expertise. Casual leisure behaviors provide short-term gratification, but they do not provide long-term gratification or personal identity. These include play , relaxation, casual social interaction, volunteering , passive entertainment, active entertainment, and sensory stimulation. Passive entertainment is typically derived from mass media , which may include written works or digital media . Active entertainment involves games in which individuals participate. Sensory stimulation is immediate gratification from behaviors such as eating or sexual intercourse. Consumption [ edit ] Main article: Consumer behaviour Humans operate as consumers that obtain and use goods. All production is ultimately designed for consumption , and consumers adapt their behavior based on the availability of production. Mass consumption began during the Industrial Revolution, caused by the development of new technologies that allowed for increased production. Many factors affect a consumer's decision to purchase goods through trade. They may consider the nature of the product, its associated cost, the convenience of purchase, and the nature of advertising around the product. Cultural factors may influence this decision, as different cultures value different things, and subcultures within these cultures may have distinct priorities as buyers. Social class , including wealth, education, and occupation may affect one's purchasing behavior. A consumer's interpersonal relationships and reference groups may also influence purchasing behavior. Ecological behavior [ edit ] Main article: Human ecology A girl with lambs in Gilandeh , Iran (2018) Like all living things, humans live in ecosystems and interact with other organisms. Human behavior is affected by the environment in which a human lives, and environments are affected by human habitation. Humans have also developed man-made ecosystems such as urban areas and agricultural land . Geography and landscape ecology determine how humans are distributed within an ecosystem, both naturally and through planned urban morphology . Humans exercise control over the animals that live within their environment. Domesticated animals are trained and cared for by humans. Humans can develop social and emotional bonds with animals in their care. Pets are kept for companionship within human homes, including dogs and cats that have been bred for domestication over many centuries. Livestock animals, such as cattle , sheep , goats , and poultry , are kept on agricultural land to produce animal products . Domesticated animals are also kept in laboratories for animal testing . Non-domesticated animals are sometimes kept in nature reserves and zoos for tourism and conservation . Causes and factors [ edit ] Human behavior is influenced by biological and cultural elements. The structure and agency debate considers whether human behavior is predominantly led by individual human impulses or by external structural forces. Behavioral genetics considers how human behavior is affected by inherited traits. Though genes do not guarantee certain behaviors, certain traits can be inherited that make individuals more likely to engage in certain behaviors or express certain personalities. An individual's environment can also affect behavior, often in conjunction with genetic factors. An individual's personality and attitudes affect how behaviors are expressed, formed in conjunction by genetic and environmental factors. Age [ edit ] Further information: Ageing An infant engaging in play in Los Angeles , California (2015) Infants are limited in their ability to interpret their surroundings shortly after birth. Object permanence and understanding of motion typically develop within the first six months of an infant's life, though the specific cognitive processes are not understood. The ability to mentally categorize different concepts and objects that they perceive also develops within the first year. Infants are quickly able to discern their body from their surroundings and often take interest in their own limbs or actions they cause by two months of age. Infants practice imitation of other individuals to engage socially and learn new behaviors. In young infants, this involves imitating facial expressions , and imitation of tool use takes place within the first year. Communication develops over the first year, and infants begin using gestures to communicate intention around nine to ten months of age. Verbal communication develops more gradually, taking form during the second year of age. Children develop fine motor skills shortly after infancy, in the range of three to six years of age, allowing them to engage in behaviors using the hands and eye–hand coordination and perform basic activities of self sufficiency . Children begin expressing more complex emotions in the three- to six-year-old range, including humor, empathy, and altruism, as well engaging in creativity and inquiry. Aggressive behaviors also become varied at this age as children engage in increased physical aggression before learning to favor diplomacy over aggression. Children at this age can express themselves using language with basic grammar. As children grow older, they develop emotional intelligence . Young children engage in basic social behaviors with peers , typically forming friendships centered on play with individuals of the same age and gender. Behaviors of young children are centered around play, which allows them to practice physical, cognitive, and social behaviors. Basic self-concept first develops as children grow, particularly centered around traits such as gender and ethnicity, and behavior is heavily affected by peers for the first time. Adolescents undergo changes in behavior caused by puberty and the associated changes in hormone production. Production of testosterone increases sensation seeking and sensitivity to rewards in adolescents as well as aggression and risk-taking in adolescent boys. Production of estradiol causes similar risk-taking behavior among adolescent girls. The new hormones cause changes in emotional processing that allow for close friendships, stronger motivations and intentions, and adolescent sexuality . Adolescents undergo social changes on a large scale, developing a full self-concept and making autonomous decisions independently of adults. They typically become more aware of social norms and social cues than children, causing an increase in self-consciousness and adolescent egocentrism that guides behavior in social settings throughout adolescence. Culture and environment [ edit ] Human brains, as with those of all mammals, are neuroplastic . This means that the structure of the brain changes over time as neural pathways are altered in response to the environment. Many behaviors are learned through interaction with others during early development of the brain. Human behavior is distinct from the behavior of other animals in that it is heavily influenced by culture and language. Social learning allows humans to develop new behaviors by following the example of others. Culture is also the guiding influence that defines social norms. Genetics [ edit ] Physiology [ edit ] Neurotransmitters , hormones , and metabolism are all recognized as biological factors in human behavior. Physical disabilities can prevent individuals from engaging in typical human behavior or necessitate alternative behaviors. Accommodations and accessibility are often made available for individuals with physical disabilities in developed nations, including health care, assistive technology , and vocational services . Severe disabilities are associated with increased leisure time but also with a lower satisfaction in the quality of leisure time. Productivity and health both commonly undergo long term decline following the onset of a severe disability. Mental disabilities are those that directly affect cognitive and social behavior. Common mental disorders include mood disorders , anxiety disorders , personality disorders , and substance dependence . See also [ edit ] Psychology portal Society portal Behavioral modernity Behaviorism Cultural ecology Human behavioral ecology References [ edit ] ^ Longino 2013 , pp. 13–14. ^ Longino 2013 , pp. 7–8. ^ Longino 2013 , p. 2. ^ Longino 2013 , p. 11. ^ Longino 2013 , p. 1. ^ Longino 2013 , p. 8. ^ Longino 2013 , pp. 9–10. ^ Longino 2013 , p. 12. ^ Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 . ^ Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 . ^ Duck 2007 , pp. 1–5. ^ Duck 2007 , pp. 10–14. ^ Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 . ^ Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 . ^ Goode 2015 , pp. 3–4. ^ Goode 2015 , p. 7. ^ Goode 2015 , p. 5. ^ Goode 2015 , p. 6. ^ Duck 2007 , p. 107. ^ Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 . ^ Duck 2007 , pp. 56–60. ^ Duck 2007 , pp. 121–125. ^ Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 . ^ Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 . ^ Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 . ^ Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation. ^ Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 . ^ Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 . ^ Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 . ^ Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 . ^ Evans 2003 , pp. 1–21. ^ Evans 2003 , pp. 47–. ^ Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 . ^ Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 . ^ " 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 . ^ Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 . ^ Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 . ^ Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 . ^ McKeown, Thomas (1980). The Role of Medicine . Princeton University Press. p. 78. ISBN 978-1400854622 . ^ Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 . ^ Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 . ^ Baggott, L. M. (1997). Human Reproduction . Cambridge University Press. p. 5. ISBN 978-0521469142 . ^ Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 . ^ Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 . ^ Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 . ^ Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 . ^ Neff 1985 , pp. 24–33. ^ Neff 1985 , pp. 41–46. ^ Neff 1985 , p. 2. ^ Neff 1985 , pp. 142–153. ^ Neff 1985 , pp. 79–80. ^ Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 . ^ Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 . ^ Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X . ^ Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 . ^ Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 . ^ Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 . ^ Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 . ^ Bremner & Wachs 2010 , pp. 234–235. ^ Bremner & Wachs 2010 , pp. 264–265. ^ Bremner & Wachs 2010 , pp. 337–340. ^ Bremner & Wachs 2010 , pp. 346–347. ^ Bremner & Wachs 2010 , pp. 398–399. ^ Woody & Woody 2019 , pp. 259–260. ^ Woody & Woody 2019 , p. 263. ^ Woody & Woody 2019 , p. 279. ^ Woody & Woody 2019 , pp. 268–269. ^ Charlesworth 2019 , p. 346. ^ Woody & Woody 2019 , p. 281. ^ Woody & Woody 2019 , p. 290. ^ Charlesworth 2019 , p. 343. ^ Charlesworth 2019 , p. 353. ^ Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 . ^ Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 . ^ Van Schaik 2016 , Chapter 2.4. ^ Van Schaik 2016 , Chapter 3.1. ^ Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 . ^ Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 . ^ Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 . Bibliography [ edit ] Bremner, Gavin; Wachs, Theodore D., eds. (2010). The Wiley-Blackwell Handbook of Infant Development . Vol. 1: Basic Research (2nd ed.). Wiley-Blackwell. ISBN 978-1444332735 . Charlesworth, Leanne Wood (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 327–395. ISBN 978-1544339344 . LCCN 2018021374 . Duck, Steve (2007). Human Relationships (4th ed.). SAGE Publications. ISBN 978-1412929998 . Evans, Dylan (2003). Emotion: A Very Short Introduction . Oxford University Press. ISBN 978-0192804617 . Goode, Erich (2015). "The Sociology of Deviance: An Introduction". In Goode, Erich (ed.). The Handbook of Deviance . Wiley. pp. 3–29. doi : 10.1002/9781118701386 . ISBN 978-1118701324 . Longino, Helen E. (2013). Studying Human Behavior: How Scientists Investigate Aggression and Sexuality . University of Chicago Press. doi : 10.7208/9780226921822 (inactive 31 January 2024). ISBN 978-0226921822 . {{ cite book }} : CS1 maint: DOI inactive as of January 2024 ( link ) Neff, Walter S. (1985). Work and Human Behavior (3rd ed.). Aldine Publishing Company. ISBN 0202303195 . Van Schaik, Carel P. (2016). The primate origins of human nature . Foundations of human biology. Hoboken, New Jersey: Wiley-Blackwell. ISBN 978-1-119-11820-6 . Woody, Debra J.; Woody, David (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 251–326. ISBN 978-1544339344 . LCCN 2018021374 . Further reading [ edit ] Ardrey, Robert . 1970. The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder . Atheneum . ISBN 0689103476 . Sapolsky, Robert M. (2017). Behave: The Biology of Humans at Our Best and Worst . Penguin Press. ISBN 978-1594205071 . External links [ edit ] Wikiquote has quotations related to Human behavior . Media related to Human behavior at Wikimedia Commons Authority control databases International FAST National France BnF data Israel United States Japan Czech Republic Other NARA Retrieved from " https://en.wikipedia.org/w/index.php?title=Human_behavior&oldid=1215120043 "
Array of every physical action and observable emotion associated with humans For the song, see Human Behaviour . Social interaction and creative expression are forms of human behavior Part of a series on Sociology History Outline Index Key themes Society Globalization Human behavior Human environmental impact Identity Industrial revolutions 3 / 4 / 5 Social complexity Social construct Social environment Social equality Social equity Social power Social stratification Social structure Perspectives Conflict theory Critical theory Structural functionalism Positivism Social constructionism Symbolic interactionism Branches Aging Architecture Art Astrosociology Body Criminology Consciousness Culture Death Demography Deviance Disaster Economic Education Emotion ( Jealousy ) Environmental Family Feminist Fiscal Food Gender Generations Health Historical Immigration Industrial Internet Jewry Knowledge Language Law Leisure Literature Marxist Mathematic Medical Military Music Peace, war, and social conflict Philosophy Political Public Punishment Race and ethnicity Religion Rural Science ( History of science ) Social movements Social psychology Sociocybernetics Sociology Space Sport Technology Terrorism Urban Utopian Victimology Visual Methods Quantitative Qualitative Comparative Computational Ethnographic Conversation analysis Historical Interview Mathematical Network analysis Social experiment Survey Sociologists 1700s: Comte · Sieyès 1800s: Martineau · Tocqueville · Marx · Spencer · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Marcuse 1900s: Fromm · Adorno · Merton · Mills · Goffman · Bauman · Foucault · Habermas · Baudrillard · Bourdieu · Giddens Lists Bibliography Terminology Journals Organizations People Timeline By country Society portal v t e Human behavior is the potential and expressed capacity ( mentally , physically , and socially ) of human individuals or groups to respond to internal and external stimuli throughout their life. Behavior is driven by genetic and environmental factors that affect an individual. Behavior is also driven, in part, by thoughts and feelings , which provide insight into individual psyche , revealing such things as attitudes and values . Human behavior is shaped by psychological traits , as personality types vary from person to person, producing different actions and behavior. Social behavior accounts for actions directed at others. It is concerned with the considerable influence of social interaction and culture , as well as ethics , interpersonal relationships , politics , and conflict . Some behaviors are common while others are unusual. The acceptability of behavior depends upon social norms and is regulated by various means of social control . Social norms also condition behavior, whereby humans are pressured into following certain rules and displaying certain behaviors that are deemed acceptable or unacceptable depending on the given society or culture. Cognitive behavior accounts for actions of obtaining and using knowledge . It is concerned with how information is learned and passed on, as well as creative application of knowledge and personal beliefs such as religion . Physiological behavior accounts for actions to maintain the body. It is concerned with basic bodily functions as well as measures taken to maintain health. Economic behavior accounts for actions regarding the development, organization, and use of materials as well as other forms of work . Ecological behavior accounts for actions involving the ecosystem. It is concerned with how humans interact with other organisms and how the environment shapes human behavior. Study [ edit ] Main article: Human ethology Human behavior is studied by the social sciences , which include psychology , sociology , ethology , and their various branches and schools of thought. There are many different facets of human behavior, and no one definition or field study encompasses it in its entirety. The nature versus nurture debate is one of the fundamental divisions in the study of human behavior; this debate considers whether behavior is predominantly affected by genetic or environmental factors. The study of human behavior sometimes receives public attention due to its intersection with cultural issues, including crime , sexuality , and social inequality . Some natural sciences also place emphasis on human behavior. Neurology and evolutionary biology , study how behavior is controlled by the nervous system and how the human mind evolved , respectively. In other fields, human behavior may be a secondary subject of study when considering how it affects another subject. Outside of formal scientific inquiry, human behavior and the human condition is also a major focus of philosophy and literature . Philosophy of mind considers aspects such as free will , the mind–body problem , and malleability of human behavior. Human behavior may be evaluated through questionnaires , interviews , and experimental methods . Animal testing may also be used to test behaviors that can then be compared to human behavior. Twin studies are a common method by which human behavior is studied. Twins with identical genomes can be compared to isolate genetic and environmental factors in behavior. Lifestyle, susceptibility to disease, and unhealthy behaviors have been identified to have both genetic and environmental indicators through twin studies. Social behavior [ edit ] Further information: Sociology Women bowing in Japan ( c. 1880 ) Human social behavior is the behavior that considers other humans, including communication and cooperation. It is highly complex and structured, based on advanced theory of mind that allows humans to attribute thoughts and actions to one another. Through social behavior, humans have developed society and culture distinct from other animals. Human social behavior is governed by a combination of biological factors that affect all humans and cultural factors that change depending on upbringing and societal norms. Human communication is based heavily on language , typically through speech or writing . Nonverbal communication and paralanguage can modify the meaning of communications by demonstrating ideas and intent through physical and vocal behaviors. Social norms [ edit ] Human behavior in a society is governed by social norms . Social norms are unwritten expectations that members of society have for one another. These norms are ingrained in the particular culture that they emerge from, and humans often follow them unconsciously or without deliberation. These norms affect every aspect of life in human society, including decorum , social responsibility , property rights , contractual agreement , morality , justice , and meaning . Many norms facilitate coordination between members of society and prove mutually beneficial, such as norms regarding communication and agreements. Norms are enforced by social pressure , and individuals that violate social norms risk social exclusion . Systems of ethics are used to guide human behavior to determine what is moral. Humans are distinct from other animals in the use of ethical systems to determine behavior. Ethical behavior is human behavior that takes into consideration how actions will affect others and whether behaviors will be optimal for others. What constitutes ethical behavior is determined by the individual value judgments of the person and the collective social norms regarding right and wrong. Value judgments are intrinsic to people of all cultures, though the specific systems used to evaluate them may vary. These systems may be derived from divine law , natural law , civil authority , reason , or a combination of these and other principles. Altruism is an associated behavior in which humans consider the welfare of others equally or preferentially to their own. While other animals engage in biological altruism, ethical altruism is unique to humans. Deviance is behavior that violates social norms. As social norms vary between individuals and cultures, the nature and severity of a deviant act is subjective. What is considered deviant by a society may also change over time as new social norms are developed. Deviance is punished by other individuals through social stigma , censure , or violence . Many deviant actions are recognized as crimes and punished through a system of criminal justice . Deviant actions may be punished to prevent harm to others, to maintain a particular worldview and way of life, or to enforce principles of morality and decency . Cultures also attribute positive or negative value to certain physical traits, causing individuals that do not have desirable traits to be seen as deviant. Interpersonal relationships [ edit ] Main article: Interpersonal relationship A family in Noatak , Alaska (1929) Interpersonal relationships can be evaluated by the specific choices and emotions between two individuals, or they can be evaluated by the broader societal context of how such a relationship is expected to function. Relationships are developed through communication, which creates intimacy, expresses emotions, and develops identity. An individual's interpersonal relationships form a social group in which individuals all communicate and socialize with one another, and these social groups are connected by additional relationships. Human social behavior is affected not only by individual relationships, but also by how behaviors in one relationship may affect others. Individuals that actively seek out social interactions are extraverts , and those that do not are introverts. Romantic love is a significant interpersonal attraction toward another. Its nature varies by culture, but it is often contingent on gender, occurring in conjunction with sexual attraction and being either heterosexual or homosexual . It takes different forms and is associated with many individual emotions. Many cultures place a higher emphasis on romantic love than other forms of interpersonal attraction. Marriage is a union between two people, though whether it is associated with romantic love is dependent on the culture. Individuals that are closely related by consanguinity form a family . There are many variations on family structures that may include parents and children as well as stepchildren or extended relatives. Family units with children emphasize parenting , in which parents engage in a high level of parental investment to protect and instruct children as they develop over a period of time longer than that of most other mammals. Politics and conflict [ edit ] Further information: Political science , Theories of political behavior , and Conflict (process) A depiction of men fighting in the First Battle of Komárom (1849) When humans make decisions as a group, they engage in politics. Humans have evolved to engage in behaviors of self-interest , but this also includes behaviors that facilitate cooperation rather than conflict in collective settings. Individuals will often form in-group and out-group perceptions, through which individuals cooperate with the in-group and compete with the out-group. This causes behaviors such as unconsciously conforming, passively obeying authority, taking pleasure in the misfortune of opponents, initiating hostility toward out-group members, artificially creating out-groups when none exist, and punishing those that do not comply with the standards of the in-group. These behaviors lead to the creation of political systems that enforce in-group standards and norms. When humans oppose one another, it creates conflict. It may occur when the involved parties have a disagreement of opinion, when one party obstructs the goals of another, or when parties experience negative emotions such as anger toward one another. Conflicts purely of disagreement are often resolved through communication or negotiation , but incorporation of emotional or obstructive aspects can escalate conflict. Interpersonal conflict is that between specific individuals or groups of individuals. Social conflict is that between different social groups or demographics. This form of conflict often takes place when groups in society are marginalized, do not have the resources they desire, wish to instigate social change, or wish to resist social change. Significant social conflict can cause civil disorder . International conflict is that between nations or governments. It may be solved through diplomacy or war . Cognitive behavior [ edit ] Main article: Cognition People being taught to paint in Volgograd , Russia (2013) Human cognition is distinct from that of other animals. This is derived from biological traits of human cognition, but also from shared knowledge and development passed down culturally. Humans are able to learn from one another due to advanced theory of mind that allows knowledge to be obtained through education . The use of language allows humans to directly pass knowledge to one another. The human brain has neuroplasticity , allowing it to modify its features in response to new experiences. This facilitates learning in humans and leads to behaviors of practice , allowing the development of new skills in individual humans. Behavior carried out over time can be ingrained as a habit , where humans will continue to regularly engage in the behavior without consciously deciding to do so. Humans engage in reason to make inferences with a limited amount of information. Most human reasoning is done automatically without conscious effort on the part of the individual. Reasoning is carried out by making generalizations from past experiences and applying them to new circumstances. Learned knowledge is acquired to make more accurate inferences about the subject. Deductive reasoning infers conclusions that are true based on logical premises, while inductive reasoning infers what conclusions are likely to be true based on context. Emotion is a cognitive experience innate to humans. Basic emotions such as joy , distress , anger , fear , surprise , and disgust are common to all cultures, though social norms regarding the expression of emotion may vary. Other emotions come from higher cognition, such as love , guilt , shame , embarrassment , pride , envy , and jealousy . These emotions develop over time rather than instantly and are more strongly influenced by cultural factors. Emotions are influenced by sensory information , such as color and music , and moods of happiness and sadness . Humans typically maintain a standard level of happiness or sadness determined by health and social relationships, though positive and negative events have short-term influences on mood. Humans often seek to improve the moods of one another through consolation , entertainment , and venting . Humans can also self-regulate mood through exercise and meditation . Creativity is the use of previous ideas or resources to produce something original. It allows for innovation , adaptation to change, learning new information, and novel problem solving. Expression of creativity also supports quality of life . Creativity includes personal creativity, in which a person presents new ideas authentically , but it can also be expanded to social creativity, in which a community or society produces and recognizes ideas collectively. Creativity is applied in typical human life to solve problems as they occur. It also leads humans to carry out art and science . Individuals engaging in advanced creative work typically have specialized knowledge in that field, and humans draw on this knowledge to develop novel ideas. In art, creativity is used to develop new artistic works, such as visual art or music . In science, those with knowledge in a particular scientific field can use trial and error to develop theories that more accurately explain phenomena. Religious behavior is a set of traditions that are followed based on the teachings of a religious belief system. The nature of religious behavior varies depending on the specific religious traditions. Most religious traditions involve variations of telling myths , practicing rituals , making certain things taboo , adopting symbolism , determining morality, experiencing altered states of consciousness , and believing in supernatural beings. Religious behavior is often demanding and has high time, energy, and material costs, and it conflicts with rational choice models of human behavior, though it does provide community-related benefits. Anthropologists offer competing theories as to why humans adopted religious behavior. Religious behavior is heavily influenced by social factors, and group involvement is significant in the development of an individual's religious behavior. Social structures such as religious organizations or family units allow the sharing and coordination of religious behavior. These social connections reinforce the cognitive behaviors associated with religion, encouraging orthodoxy and commitment. According to a Pew Research Center report, 54% of adults around the world state that religion is very important in their lives as of 2018. Physiological behavior [ edit ] See also: Psychophysiology A boy eating in Harare , Zimbabwe (2017) Humans undergo many behaviors common to animals to support the processes of the human body . Humans eat food to obtain nutrition . These foods may be chosen for their nutritional value, but they may also be eaten for pleasure . Eating often follows a food preparation process to make it more enjoyable. Humans dispose of excess food through waste . Excrement is often treated as taboo, particularly in developed and urban communities where sanitation is more widely available and excrement has no value as fertilizer . Humans also regularly engage in sleep , based on homeostatic and circadian factors. The circadian rhythm causes humans to require sleep at a regular pattern and is typically calibrated to the day-night cycle and sleep-wake habits. Homeostasis is also be maintained, causing longer sleep longer after periods of sleep deprivation . The human sleep cycle takes place over 90 minutes, and it repeats 3–5 times during normal sleep. There are also unique behaviors that humans undergo to maintain physical health. Humans have developed medicine to prevent and treat illnesses. In industrialized nations, eating habits that favor better nutrition, hygienic behaviors that promote sanitation , medical treatment to eradicate diseases, and the use of birth control significantly improve human health. Humans can also engage in exercise beyond that required for survival to maintain health. Humans engage in hygiene to limit exposure to dirt and pathogens . Some of these behaviors are adaptive while others are learned. Basic behaviors of disgust evolved as an adaptation to prevent contact with sources of pathogens, resulting in a biological aversion to feces , body fluids , rotten food , and animals that are commonly disease vectors . Personal grooming , disposal of human corpses , use of sewerage , and use of cleaning agents are hygienic behaviors common to most human societies. Humans reproduce sexually , engaging in sexual intercourse for both reproduction and sexual pleasure . Human reproduction is closely associated with human sexuality and an instinctive desire to procreate , though humans are unique in that they intentionally control the number of offspring that they produce. Humans engage in a large variety of reproductive behaviors relative to other animals, with various mating structures that include forms of monogamy , polygyny , and polyandry . How humans engage in mating behavior is heavily influenced by cultural norms and customs. Unlike most mammals, human women ovulate spontaneously rather than seasonally, with a menstrual cycle that typically lasts 25–35 days. Humans are bipedal and move by walking . Human walking corresponds to the bipedal gait cycle , which involves alternating heel contact and toe off with the ground and slight elevation and rotation of the pelvis . Balance while walking learned during the first 7–9 years of life, and individual humans develop unique gaits while learning to displace weight, adjust center of mass , and correspond neural control with movement. Humans can achieve higher speed by running . The endurance running hypothesis proposes that humans can outpace most other animals over long distances through running, though human running causes a higher rate of energy exertion. The human body self-regulates through perspiration during periods of exertion, allowing humans more endurance than other animals. The human hand is prehensile and capable of grasping objects and applying force with control over the hand's dexterity and grip strength . This allows the use of complex tools by humans. Economic behavior [ edit ] Further information: Behavioral economics Humans engage in predictable behaviors when considering economic decisions, and these behaviors may or may not be rational . Like all animals, humans make basic decisions through cost–benefit analysis and the risk–return spectrum , though humans are able to contemplate these decisions more thoroughly. Human economic decision making is often reference dependent , in which options are weighed in reference to the status quo rather than absolute gains and losses. Humans are also loss averse , fearing loss rather than seeking gain. Advanced economic behavior developed in humans after the Neolithic Revolution and the development of agriculture . These developments led to a sustainable supply of resources that allowed specialization in more complex societies. Work [ edit ] Main article: Work (human activity) Women tending to farm animals in Mangskogs, Sweden (1911) The nature of human work is defined by the complexity of society. The simplest societies are tribes that work primarily for sustenance as hunter-gatherers . In this sense, work is not a distinct activity but a constant that makes up all parts of life, as all members of the society must work consistently to stay alive. More advanced societies developed after the Neolithic Revolution, emphasizing work in agricultural and pastoral settings. In these societies, production is increased, ending the need for constant work and allowing some individuals to specialize and work in areas outside of food-production. This also created non-laborious work, as increasing occupational complexity required some individuals to specialize in technical knowledge and administration. Laborious work in these societies has variously been carried out by slaves, serfs, peasants, and guild craftsmen. The nature of work changed significantly during the Industrial Revolution in which the factory system was developed for use by industrializing nations. In addition to further increasing general quality of life, this development changed the dynamic of work. Under the factory system, workers increasingly collaborate with others, employers serve as authority figures during work hours, and forced labor is largely eradicated. Further changes occur in post-industrial societies where technological advance makes industries obsolete, replacing them with mass production and service industries . Humans approach work differently based on both physical and personal attributes, and some work with more effectiveness and commitment than others. Some find work to contribute to personal fulfillment, while others work only out of necessity. Work can also serve as an identity, with individuals identifying themselves based on their occupation. Work motivation is complex, both contributing to and subtracting from various human needs. The primary motivation for work is for material gain, which takes the form of money in modern societies. It may also serve to create self-esteem and personal worth, provide activity, gain respect, and express creativity. Modern work is typically categorized as laborious or blue-collar work and non-laborious or white-collar work . Leisure [ edit ] Main article: Leisure Men playing association football in Kilkenny , Ireland (2007) Leisure is activity or lack of activity that takes place outside of work. It provides relaxation, entertainment , and improved quality of life for individuals. Engaging in leisure can be beneficial for physical and mental health. It may be used to seek temporary relief from psychological stress , to produce positive emotions, or to facilitate social interaction. Leisure can also facilitate health risks and negative emotions caused by boredom , substance abuse , or high-risk behavior . Leisure may be defined as serious or casual. Serious leisure behaviors involve non-professional pursuit of arts and sciences, the development of hobbies , or career volunteering in an area of expertise. Casual leisure behaviors provide short-term gratification, but they do not provide long-term gratification or personal identity. These include play , relaxation, casual social interaction, volunteering , passive entertainment, active entertainment, and sensory stimulation. Passive entertainment is typically derived from mass media , which may include written works or digital media . Active entertainment involves games in which individuals participate. Sensory stimulation is immediate gratification from behaviors such as eating or sexual intercourse. Consumption [ edit ] Main article: Consumer behaviour Humans operate as consumers that obtain and use goods. All production is ultimately designed for consumption , and consumers adapt their behavior based on the availability of production. Mass consumption began during the Industrial Revolution, caused by the development of new technologies that allowed for increased production. Many factors affect a consumer's decision to purchase goods through trade. They may consider the nature of the product, its associated cost, the convenience of purchase, and the nature of advertising around the product. Cultural factors may influence this decision, as different cultures value different things, and subcultures within these cultures may have distinct priorities as buyers. Social class , including wealth, education, and occupation may affect one's purchasing behavior. A consumer's interpersonal relationships and reference groups may also influence purchasing behavior. Ecological behavior [ edit ] Main article: Human ecology A girl with lambs in Gilandeh , Iran (2018) Like all living things, humans live in ecosystems and interact with other organisms. Human behavior is affected by the environment in which a human lives, and environments are affected by human habitation. Humans have also developed man-made ecosystems such as urban areas and agricultural land . Geography and landscape ecology determine how humans are distributed within an ecosystem, both naturally and through planned urban morphology . Humans exercise control over the animals that live within their environment. Domesticated animals are trained and cared for by humans. Humans can develop social and emotional bonds with animals in their care. Pets are kept for companionship within human homes, including dogs and cats that have been bred for domestication over many centuries. Livestock animals, such as cattle , sheep , goats , and poultry , are kept on agricultural land to produce animal products . Domesticated animals are also kept in laboratories for animal testing . Non-domesticated animals are sometimes kept in nature reserves and zoos for tourism and conservation . Causes and factors [ edit ] Human behavior is influenced by biological and cultural elements. The structure and agency debate considers whether human behavior is predominantly led by individual human impulses or by external structural forces. Behavioral genetics considers how human behavior is affected by inherited traits. Though genes do not guarantee certain behaviors, certain traits can be inherited that make individuals more likely to engage in certain behaviors or express certain personalities. An individual's environment can also affect behavior, often in conjunction with genetic factors. An individual's personality and attitudes affect how behaviors are expressed, formed in conjunction by genetic and environmental factors. Age [ edit ] Further information: Ageing An infant engaging in play in Los Angeles , California (2015) Infants are limited in their ability to interpret their surroundings shortly after birth. Object permanence and understanding of motion typically develop within the first six months of an infant's life, though the specific cognitive processes are not understood. The ability to mentally categorize different concepts and objects that they perceive also develops within the first year. Infants are quickly able to discern their body from their surroundings and often take interest in their own limbs or actions they cause by two months of age. Infants practice imitation of other individuals to engage socially and learn new behaviors. In young infants, this involves imitating facial expressions , and imitation of tool use takes place within the first year. Communication develops over the first year, and infants begin using gestures to communicate intention around nine to ten months of age. Verbal communication develops more gradually, taking form during the second year of age. Children develop fine motor skills shortly after infancy, in the range of three to six years of age, allowing them to engage in behaviors using the hands and eye–hand coordination and perform basic activities of self sufficiency . Children begin expressing more complex emotions in the three- to six-year-old range, including humor, empathy, and altruism, as well engaging in creativity and inquiry. Aggressive behaviors also become varied at this age as children engage in increased physical aggression before learning to favor diplomacy over aggression. Children at this age can express themselves using language with basic grammar. As children grow older, they develop emotional intelligence . Young children engage in basic social behaviors with peers , typically forming friendships centered on play with individuals of the same age and gender. Behaviors of young children are centered around play, which allows them to practice physical, cognitive, and social behaviors. Basic self-concept first develops as children grow, particularly centered around traits such as gender and ethnicity, and behavior is heavily affected by peers for the first time. Adolescents undergo changes in behavior caused by puberty and the associated changes in hormone production. Production of testosterone increases sensation seeking and sensitivity to rewards in adolescents as well as aggression and risk-taking in adolescent boys. Production of estradiol causes similar risk-taking behavior among adolescent girls. The new hormones cause changes in emotional processing that allow for close friendships, stronger motivations and intentions, and adolescent sexuality . Adolescents undergo social changes on a large scale, developing a full self-concept and making autonomous decisions independently of adults. They typically become more aware of social norms and social cues than children, causing an increase in self-consciousness and adolescent egocentrism that guides behavior in social settings throughout adolescence. Culture and environment [ edit ] Human brains, as with those of all mammals, are neuroplastic . This means that the structure of the brain changes over time as neural pathways are altered in response to the environment. Many behaviors are learned through interaction with others during early development of the brain. Human behavior is distinct from the behavior of other animals in that it is heavily influenced by culture and language. Social learning allows humans to develop new behaviors by following the example of others. Culture is also the guiding influence that defines social norms. Genetics [ edit ] Physiology [ edit ] Neurotransmitters , hormones , and metabolism are all recognized as biological factors in human behavior. Physical disabilities can prevent individuals from engaging in typical human behavior or necessitate alternative behaviors. Accommodations and accessibility are often made available for individuals with physical disabilities in developed nations, including health care, assistive technology , and vocational services . Severe disabilities are associated with increased leisure time but also with a lower satisfaction in the quality of leisure time. Productivity and health both commonly undergo long term decline following the onset of a severe disability. Mental disabilities are those that directly affect cognitive and social behavior. Common mental disorders include mood disorders , anxiety disorders , personality disorders , and substance dependence . See also [ edit ] Psychology portal Society portal Behavioral modernity Behaviorism Cultural ecology Human behavioral ecology References [ edit ] ^ Longino 2013 , pp. 13–14. ^ Longino 2013 , pp. 7–8. ^ Longino 2013 , p. 2. ^ Longino 2013 , p. 11. ^ Longino 2013 , p. 1. ^ Longino 2013 , p. 8. ^ Longino 2013 , pp. 9–10. ^ Longino 2013 , p. 12. ^ Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 . ^ Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 . ^ Duck 2007 , pp. 1–5. ^ Duck 2007 , pp. 10–14. ^ Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 . ^ Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 . ^ Goode 2015 , pp. 3–4. ^ Goode 2015 , p. 7. ^ Goode 2015 , p. 5. ^ Goode 2015 , p. 6. ^ Duck 2007 , p. 107. ^ Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 . ^ Duck 2007 , pp. 56–60. ^ Duck 2007 , pp. 121–125. ^ Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 . ^ Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 . ^ Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 . ^ Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation. ^ Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 . ^ Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 . ^ Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 . ^ Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 . ^ Evans 2003 , pp. 1–21. ^ Evans 2003 , pp. 47–. ^ Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 . ^ Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 . ^ " 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 . ^ Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 . ^ Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 . ^ Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 . ^ McKeown, Thomas (1980). The Role of Medicine . Princeton University Press. p. 78. ISBN 978-1400854622 . ^ Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 . ^ Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 . ^ Baggott, L. M. (1997). Human Reproduction . Cambridge University Press. p. 5. ISBN 978-0521469142 . ^ Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 . ^ Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 . ^ Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 . ^ Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 . ^ Neff 1985 , pp. 24–33. ^ Neff 1985 , pp. 41–46. ^ Neff 1985 , p. 2. ^ Neff 1985 , pp. 142–153. ^ Neff 1985 , pp. 79–80. ^ Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 . ^ Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 . ^ Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X . ^ Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 . ^ Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 . ^ Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 . ^ Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 . ^ Bremner & Wachs 2010 , pp. 234–235. ^ Bremner & Wachs 2010 , pp. 264–265. ^ Bremner & Wachs 2010 , pp. 337–340. ^ Bremner & Wachs 2010 , pp. 346–347. ^ Bremner & Wachs 2010 , pp. 398–399. ^ Woody & Woody 2019 , pp. 259–260. ^ Woody & Woody 2019 , p. 263. ^ Woody & Woody 2019 , p. 279. ^ Woody & Woody 2019 , pp. 268–269. ^ Charlesworth 2019 , p. 346. ^ Woody & Woody 2019 , p. 281. ^ Woody & Woody 2019 , p. 290. ^ Charlesworth 2019 , p. 343. ^ Charlesworth 2019 , p. 353. ^ Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 . ^ Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 . ^ Van Schaik 2016 , Chapter 2.4. ^ Van Schaik 2016 , Chapter 3.1. ^ Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 . ^ Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 . ^ Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 . Bibliography [ edit ] Bremner, Gavin; Wachs, Theodore D., eds. (2010). The Wiley-Blackwell Handbook of Infant Development . Vol. 1: Basic Research (2nd ed.). Wiley-Blackwell. ISBN 978-1444332735 . Charlesworth, Leanne Wood (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 327–395. ISBN 978-1544339344 . LCCN 2018021374 . Duck, Steve (2007). Human Relationships (4th ed.). SAGE Publications. ISBN 978-1412929998 . Evans, Dylan (2003). Emotion: A Very Short Introduction . Oxford University Press. ISBN 978-0192804617 . Goode, Erich (2015). "The Sociology of Deviance: An Introduction". In Goode, Erich (ed.). The Handbook of Deviance . Wiley. pp. 3–29. doi : 10.1002/9781118701386 . ISBN 978-1118701324 . Longino, Helen E. (2013). Studying Human Behavior: How Scientists Investigate Aggression and Sexuality . University of Chicago Press. doi : 10.7208/9780226921822 (inactive 31 January 2024). ISBN 978-0226921822 . {{ cite book }} : CS1 maint: DOI inactive as of January 2024 ( link ) Neff, Walter S. (1985). Work and Human Behavior (3rd ed.). Aldine Publishing Company. ISBN 0202303195 . Van Schaik, Carel P. (2016). The primate origins of human nature . Foundations of human biology. Hoboken, New Jersey: Wiley-Blackwell. ISBN 978-1-119-11820-6 . Woody, Debra J.; Woody, David (2019). "Early Childhood". In Hutchison, Elizabeth D. (ed.). Dimensions of Human Behavior: The Changing Life Course (6th ed.). SAGE Publications. pp. 251–326. ISBN 978-1544339344 . LCCN 2018021374 . Further reading [ edit ] Ardrey, Robert . 1970. The Social Contract: A Personal Inquiry into the Evolutionary Sources of Order and Disorder . Atheneum . ISBN 0689103476 . Sapolsky, Robert M. (2017). Behave: The Biology of Humans at Our Best and Worst . Penguin Press. ISBN 978-1594205071 . External links [ edit ] Wikiquote has quotations related to Human behavior . Media related to Human behavior at Wikimedia Commons Authority control databases International FAST National France BnF data Israel United States Japan Czech Republic Other NARA
Key themes Society Globalization Human behavior Human environmental impact Identity Industrial revolutions 3 / 4 / 5 Social complexity Social construct Social environment Social equality Social equity Social power Social stratification Social structure
Society Globalization Human behavior Human environmental impact Identity Industrial revolutions 3 / 4 / 5 Social complexity Social construct Social environment Social equality Social equity Social power Social stratification Social structure
Perspectives Conflict theory Critical theory Structural functionalism Positivism Social constructionism Symbolic interactionism
Conflict theory Critical theory Structural functionalism Positivism Social constructionism Symbolic interactionism
Branches Aging Architecture Art Astrosociology Body Criminology Consciousness Culture Death Demography Deviance Disaster Economic Education Emotion ( Jealousy ) Environmental Family Feminist Fiscal Food Gender Generations Health Historical Immigration Industrial Internet Jewry Knowledge Language Law Leisure Literature Marxist Mathematic Medical Military Music Peace, war, and social conflict Philosophy Political Public Punishment Race and ethnicity Religion Rural Science ( History of science ) Social movements Social psychology Sociocybernetics Sociology Space Sport Technology Terrorism Urban Utopian Victimology Visual
Aging Architecture Art Astrosociology Body Criminology Consciousness Culture Death Demography Deviance Disaster Economic Education Emotion ( Jealousy ) Environmental Family Feminist Fiscal Food Gender Generations Health Historical Immigration Industrial Internet Jewry Knowledge Language Law Leisure Literature Marxist Mathematic Medical Military Music Peace, war, and social conflict Philosophy Political Public Punishment Race and ethnicity Religion Rural Science ( History of science ) Social movements Social psychology Sociocybernetics Sociology Space Sport Technology Terrorism Urban Utopian Victimology Visual
Methods Quantitative Qualitative Comparative Computational Ethnographic Conversation analysis Historical Interview Mathematical Network analysis Social experiment Survey
Quantitative Qualitative Comparative Computational Ethnographic Conversation analysis Historical Interview Mathematical Network analysis Social experiment Survey
Sociologists 1700s: Comte · Sieyès 1800s: Martineau · Tocqueville · Marx · Spencer · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Marcuse 1900s: Fromm · Adorno · Merton · Mills · Goffman · Bauman · Foucault · Habermas · Baudrillard · Bourdieu · Giddens
1700s: Comte · Sieyès 1800s: Martineau · Tocqueville · Marx · Spencer · Pareto · Tönnies · Veblen · Simmel · Durkheim · Addams · Mead · Weber · Du Bois · Marcuse 1900s: Fromm · Adorno · Merton · Mills · Goffman · Bauman · Foucault · Habermas · Baudrillard · Bourdieu · Giddens
Human behavior is the potential and expressed capacity ( mentally , physically , and socially ) of human individuals or groups to respond to internal and external stimuli throughout their life. Behavior is driven by genetic and environmental factors that affect an individual. Behavior is also driven, in part, by thoughts and feelings , which provide insight into individual psyche , revealing such things as attitudes and values . Human behavior is shaped by psychological traits , as personality types vary from person to person, producing different actions and behavior.
Social behavior accounts for actions directed at others. It is concerned with the considerable influence of social interaction and culture , as well as ethics , interpersonal relationships , politics , and conflict . Some behaviors are common while others are unusual. The acceptability of behavior depends upon social norms and is regulated by various means of social control . Social norms also condition behavior, whereby humans are pressured into following certain rules and displaying certain behaviors that are deemed acceptable or unacceptable depending on the given society or culture.
Cognitive behavior accounts for actions of obtaining and using knowledge . It is concerned with how information is learned and passed on, as well as creative application of knowledge and personal beliefs such as religion . Physiological behavior accounts for actions to maintain the body. It is concerned with basic bodily functions as well as measures taken to maintain health. Economic behavior accounts for actions regarding the development, organization, and use of materials as well as other forms of work . Ecological behavior accounts for actions involving the ecosystem. It is concerned with how humans interact with other organisms and how the environment shapes human behavior.
Human behavior is studied by the social sciences , which include psychology , sociology , ethology , and their various branches and schools of thought. There are many different facets of human behavior, and no one definition or field study encompasses it in its entirety. The nature versus nurture debate is one of the fundamental divisions in the study of human behavior; this debate considers whether behavior is predominantly affected by genetic or environmental factors. The study of human behavior sometimes receives public attention due to its intersection with cultural issues, including crime , sexuality , and social inequality .
Some natural sciences also place emphasis on human behavior. Neurology and evolutionary biology , study how behavior is controlled by the nervous system and how the human mind evolved , respectively. In other fields, human behavior may be a secondary subject of study when considering how it affects another subject. Outside of formal scientific inquiry, human behavior and the human condition is also a major focus of philosophy and literature . Philosophy of mind considers aspects such as free will , the mind–body problem , and malleability of human behavior.
Human behavior may be evaluated through questionnaires , interviews , and experimental methods . Animal testing may also be used to test behaviors that can then be compared to human behavior. Twin studies are a common method by which human behavior is studied. Twins with identical genomes can be compared to isolate genetic and environmental factors in behavior. Lifestyle, susceptibility to disease, and unhealthy behaviors have been identified to have both genetic and environmental indicators through twin studies.
Human social behavior is the behavior that considers other humans, including communication and cooperation. It is highly complex and structured, based on advanced theory of mind that allows humans to attribute thoughts and actions to one another. Through social behavior, humans have developed society and culture distinct from other animals. Human social behavior is governed by a combination of biological factors that affect all humans and cultural factors that change depending on upbringing and societal norms. Human communication is based heavily on language , typically through speech or writing . Nonverbal communication and paralanguage can modify the meaning of communications by demonstrating ideas and intent through physical and vocal behaviors.
Human behavior in a society is governed by social norms . Social norms are unwritten expectations that members of society have for one another. These norms are ingrained in the particular culture that they emerge from, and humans often follow them unconsciously or without deliberation. These norms affect every aspect of life in human society, including decorum , social responsibility , property rights , contractual agreement , morality , justice , and meaning . Many norms facilitate coordination between members of society and prove mutually beneficial, such as norms regarding communication and agreements. Norms are enforced by social pressure , and individuals that violate social norms risk social exclusion .
Systems of ethics are used to guide human behavior to determine what is moral. Humans are distinct from other animals in the use of ethical systems to determine behavior. Ethical behavior is human behavior that takes into consideration how actions will affect others and whether behaviors will be optimal for others. What constitutes ethical behavior is determined by the individual value judgments of the person and the collective social norms regarding right and wrong. Value judgments are intrinsic to people of all cultures, though the specific systems used to evaluate them may vary. These systems may be derived from divine law , natural law , civil authority , reason , or a combination of these and other principles. Altruism is an associated behavior in which humans consider the welfare of others equally or preferentially to their own. While other animals engage in biological altruism, ethical altruism is unique to humans.
Deviance is behavior that violates social norms. As social norms vary between individuals and cultures, the nature and severity of a deviant act is subjective. What is considered deviant by a society may also change over time as new social norms are developed. Deviance is punished by other individuals through social stigma , censure , or violence . Many deviant actions are recognized as crimes and punished through a system of criminal justice . Deviant actions may be punished to prevent harm to others, to maintain a particular worldview and way of life, or to enforce principles of morality and decency . Cultures also attribute positive or negative value to certain physical traits, causing individuals that do not have desirable traits to be seen as deviant.
Interpersonal relationships can be evaluated by the specific choices and emotions between two individuals, or they can be evaluated by the broader societal context of how such a relationship is expected to function. Relationships are developed through communication, which creates intimacy, expresses emotions, and develops identity. An individual's interpersonal relationships form a social group in which individuals all communicate and socialize with one another, and these social groups are connected by additional relationships. Human social behavior is affected not only by individual relationships, but also by how behaviors in one relationship may affect others. Individuals that actively seek out social interactions are extraverts , and those that do not are introverts.
Romantic love is a significant interpersonal attraction toward another. Its nature varies by culture, but it is often contingent on gender, occurring in conjunction with sexual attraction and being either heterosexual or homosexual . It takes different forms and is associated with many individual emotions. Many cultures place a higher emphasis on romantic love than other forms of interpersonal attraction. Marriage is a union between two people, though whether it is associated with romantic love is dependent on the culture. Individuals that are closely related by consanguinity form a family . There are many variations on family structures that may include parents and children as well as stepchildren or extended relatives. Family units with children emphasize parenting , in which parents engage in a high level of parental investment to protect and instruct children as they develop over a period of time longer than that of most other mammals.
When humans make decisions as a group, they engage in politics. Humans have evolved to engage in behaviors of self-interest , but this also includes behaviors that facilitate cooperation rather than conflict in collective settings. Individuals will often form in-group and out-group perceptions, through which individuals cooperate with the in-group and compete with the out-group. This causes behaviors such as unconsciously conforming, passively obeying authority, taking pleasure in the misfortune of opponents, initiating hostility toward out-group members, artificially creating out-groups when none exist, and punishing those that do not comply with the standards of the in-group. These behaviors lead to the creation of political systems that enforce in-group standards and norms.
When humans oppose one another, it creates conflict. It may occur when the involved parties have a disagreement of opinion, when one party obstructs the goals of another, or when parties experience negative emotions such as anger toward one another. Conflicts purely of disagreement are often resolved through communication or negotiation , but incorporation of emotional or obstructive aspects can escalate conflict. Interpersonal conflict is that between specific individuals or groups of individuals. Social conflict is that between different social groups or demographics. This form of conflict often takes place when groups in society are marginalized, do not have the resources they desire, wish to instigate social change, or wish to resist social change. Significant social conflict can cause civil disorder . International conflict is that between nations or governments. It may be solved through diplomacy or war .
Human cognition is distinct from that of other animals. This is derived from biological traits of human cognition, but also from shared knowledge and development passed down culturally. Humans are able to learn from one another due to advanced theory of mind that allows knowledge to be obtained through education . The use of language allows humans to directly pass knowledge to one another. The human brain has neuroplasticity , allowing it to modify its features in response to new experiences. This facilitates learning in humans and leads to behaviors of practice , allowing the development of new skills in individual humans. Behavior carried out over time can be ingrained as a habit , where humans will continue to regularly engage in the behavior without consciously deciding to do so.
Humans engage in reason to make inferences with a limited amount of information. Most human reasoning is done automatically without conscious effort on the part of the individual. Reasoning is carried out by making generalizations from past experiences and applying them to new circumstances. Learned knowledge is acquired to make more accurate inferences about the subject. Deductive reasoning infers conclusions that are true based on logical premises, while inductive reasoning infers what conclusions are likely to be true based on context.
Emotion is a cognitive experience innate to humans. Basic emotions such as joy , distress , anger , fear , surprise , and disgust are common to all cultures, though social norms regarding the expression of emotion may vary. Other emotions come from higher cognition, such as love , guilt , shame , embarrassment , pride , envy , and jealousy . These emotions develop over time rather than instantly and are more strongly influenced by cultural factors. Emotions are influenced by sensory information , such as color and music , and moods of happiness and sadness . Humans typically maintain a standard level of happiness or sadness determined by health and social relationships, though positive and negative events have short-term influences on mood. Humans often seek to improve the moods of one another through consolation , entertainment , and venting . Humans can also self-regulate mood through exercise and meditation .
Creativity is the use of previous ideas or resources to produce something original. It allows for innovation , adaptation to change, learning new information, and novel problem solving. Expression of creativity also supports quality of life . Creativity includes personal creativity, in which a person presents new ideas authentically , but it can also be expanded to social creativity, in which a community or society produces and recognizes ideas collectively. Creativity is applied in typical human life to solve problems as they occur. It also leads humans to carry out art and science . Individuals engaging in advanced creative work typically have specialized knowledge in that field, and humans draw on this knowledge to develop novel ideas. In art, creativity is used to develop new artistic works, such as visual art or music . In science, those with knowledge in a particular scientific field can use trial and error to develop theories that more accurately explain phenomena.
Religious behavior is a set of traditions that are followed based on the teachings of a religious belief system. The nature of religious behavior varies depending on the specific religious traditions. Most religious traditions involve variations of telling myths , practicing rituals , making certain things taboo , adopting symbolism , determining morality, experiencing altered states of consciousness , and believing in supernatural beings. Religious behavior is often demanding and has high time, energy, and material costs, and it conflicts with rational choice models of human behavior, though it does provide community-related benefits. Anthropologists offer competing theories as to why humans adopted religious behavior. Religious behavior is heavily influenced by social factors, and group involvement is significant in the development of an individual's religious behavior. Social structures such as religious organizations or family units allow the sharing and coordination of religious behavior. These social connections reinforce the cognitive behaviors associated with religion, encouraging orthodoxy and commitment. According to a Pew Research Center report, 54% of adults around the world state that religion is very important in their lives as of 2018.
Humans undergo many behaviors common to animals to support the processes of the human body . Humans eat food to obtain nutrition . These foods may be chosen for their nutritional value, but they may also be eaten for pleasure . Eating often follows a food preparation process to make it more enjoyable. Humans dispose of excess food through waste . Excrement is often treated as taboo, particularly in developed and urban communities where sanitation is more widely available and excrement has no value as fertilizer . Humans also regularly engage in sleep , based on homeostatic and circadian factors. The circadian rhythm causes humans to require sleep at a regular pattern and is typically calibrated to the day-night cycle and sleep-wake habits. Homeostasis is also be maintained, causing longer sleep longer after periods of sleep deprivation . The human sleep cycle takes place over 90 minutes, and it repeats 3–5 times during normal sleep.
There are also unique behaviors that humans undergo to maintain physical health. Humans have developed medicine to prevent and treat illnesses. In industrialized nations, eating habits that favor better nutrition, hygienic behaviors that promote sanitation , medical treatment to eradicate diseases, and the use of birth control significantly improve human health. Humans can also engage in exercise beyond that required for survival to maintain health. Humans engage in hygiene to limit exposure to dirt and pathogens . Some of these behaviors are adaptive while others are learned. Basic behaviors of disgust evolved as an adaptation to prevent contact with sources of pathogens, resulting in a biological aversion to feces , body fluids , rotten food , and animals that are commonly disease vectors . Personal grooming , disposal of human corpses , use of sewerage , and use of cleaning agents are hygienic behaviors common to most human societies.
Humans reproduce sexually , engaging in sexual intercourse for both reproduction and sexual pleasure . Human reproduction is closely associated with human sexuality and an instinctive desire to procreate , though humans are unique in that they intentionally control the number of offspring that they produce. Humans engage in a large variety of reproductive behaviors relative to other animals, with various mating structures that include forms of monogamy , polygyny , and polyandry . How humans engage in mating behavior is heavily influenced by cultural norms and customs. Unlike most mammals, human women ovulate spontaneously rather than seasonally, with a menstrual cycle that typically lasts 25–35 days.
Humans are bipedal and move by walking . Human walking corresponds to the bipedal gait cycle , which involves alternating heel contact and toe off with the ground and slight elevation and rotation of the pelvis . Balance while walking learned during the first 7–9 years of life, and individual humans develop unique gaits while learning to displace weight, adjust center of mass , and correspond neural control with movement. Humans can achieve higher speed by running . The endurance running hypothesis proposes that humans can outpace most other animals over long distances through running, though human running causes a higher rate of energy exertion. The human body self-regulates through perspiration during periods of exertion, allowing humans more endurance than other animals. The human hand is prehensile and capable of grasping objects and applying force with control over the hand's dexterity and grip strength . This allows the use of complex tools by humans.
Humans engage in predictable behaviors when considering economic decisions, and these behaviors may or may not be rational . Like all animals, humans make basic decisions through cost–benefit analysis and the risk–return spectrum , though humans are able to contemplate these decisions more thoroughly. Human economic decision making is often reference dependent , in which options are weighed in reference to the status quo rather than absolute gains and losses. Humans are also loss averse , fearing loss rather than seeking gain. Advanced economic behavior developed in humans after the Neolithic Revolution and the development of agriculture . These developments led to a sustainable supply of resources that allowed specialization in more complex societies.
The nature of human work is defined by the complexity of society. The simplest societies are tribes that work primarily for sustenance as hunter-gatherers . In this sense, work is not a distinct activity but a constant that makes up all parts of life, as all members of the society must work consistently to stay alive. More advanced societies developed after the Neolithic Revolution, emphasizing work in agricultural and pastoral settings. In these societies, production is increased, ending the need for constant work and allowing some individuals to specialize and work in areas outside of food-production. This also created non-laborious work, as increasing occupational complexity required some individuals to specialize in technical knowledge and administration. Laborious work in these societies has variously been carried out by slaves, serfs, peasants, and guild craftsmen. The nature of work changed significantly during the Industrial Revolution in which the factory system was developed for use by industrializing nations. In addition to further increasing general quality of life, this development changed the dynamic of work. Under the factory system, workers increasingly collaborate with others, employers serve as authority figures during work hours, and forced labor is largely eradicated. Further changes occur in post-industrial societies where technological advance makes industries obsolete, replacing them with mass production and service industries .
Humans approach work differently based on both physical and personal attributes, and some work with more effectiveness and commitment than others. Some find work to contribute to personal fulfillment, while others work only out of necessity. Work can also serve as an identity, with individuals identifying themselves based on their occupation. Work motivation is complex, both contributing to and subtracting from various human needs. The primary motivation for work is for material gain, which takes the form of money in modern societies. It may also serve to create self-esteem and personal worth, provide activity, gain respect, and express creativity. Modern work is typically categorized as laborious or blue-collar work and non-laborious or white-collar work .
Leisure is activity or lack of activity that takes place outside of work. It provides relaxation, entertainment , and improved quality of life for individuals. Engaging in leisure can be beneficial for physical and mental health. It may be used to seek temporary relief from psychological stress , to produce positive emotions, or to facilitate social interaction. Leisure can also facilitate health risks and negative emotions caused by boredom , substance abuse , or high-risk behavior .
Leisure may be defined as serious or casual. Serious leisure behaviors involve non-professional pursuit of arts and sciences, the development of hobbies , or career volunteering in an area of expertise. Casual leisure behaviors provide short-term gratification, but they do not provide long-term gratification or personal identity. These include play , relaxation, casual social interaction, volunteering , passive entertainment, active entertainment, and sensory stimulation. Passive entertainment is typically derived from mass media , which may include written works or digital media . Active entertainment involves games in which individuals participate. Sensory stimulation is immediate gratification from behaviors such as eating or sexual intercourse.
Humans operate as consumers that obtain and use goods. All production is ultimately designed for consumption , and consumers adapt their behavior based on the availability of production. Mass consumption began during the Industrial Revolution, caused by the development of new technologies that allowed for increased production. Many factors affect a consumer's decision to purchase goods through trade. They may consider the nature of the product, its associated cost, the convenience of purchase, and the nature of advertising around the product. Cultural factors may influence this decision, as different cultures value different things, and subcultures within these cultures may have distinct priorities as buyers. Social class , including wealth, education, and occupation may affect one's purchasing behavior. A consumer's interpersonal relationships and reference groups may also influence purchasing behavior.
Like all living things, humans live in ecosystems and interact with other organisms. Human behavior is affected by the environment in which a human lives, and environments are affected by human habitation. Humans have also developed man-made ecosystems such as urban areas and agricultural land . Geography and landscape ecology determine how humans are distributed within an ecosystem, both naturally and through planned urban morphology .
Humans exercise control over the animals that live within their environment. Domesticated animals are trained and cared for by humans. Humans can develop social and emotional bonds with animals in their care. Pets are kept for companionship within human homes, including dogs and cats that have been bred for domestication over many centuries. Livestock animals, such as cattle , sheep , goats , and poultry , are kept on agricultural land to produce animal products . Domesticated animals are also kept in laboratories for animal testing . Non-domesticated animals are sometimes kept in nature reserves and zoos for tourism and conservation .
Human behavior is influenced by biological and cultural elements. The structure and agency debate considers whether human behavior is predominantly led by individual human impulses or by external structural forces. Behavioral genetics considers how human behavior is affected by inherited traits. Though genes do not guarantee certain behaviors, certain traits can be inherited that make individuals more likely to engage in certain behaviors or express certain personalities. An individual's environment can also affect behavior, often in conjunction with genetic factors. An individual's personality and attitudes affect how behaviors are expressed, formed in conjunction by genetic and environmental factors.
Infants are limited in their ability to interpret their surroundings shortly after birth. Object permanence and understanding of motion typically develop within the first six months of an infant's life, though the specific cognitive processes are not understood. The ability to mentally categorize different concepts and objects that they perceive also develops within the first year. Infants are quickly able to discern their body from their surroundings and often take interest in their own limbs or actions they cause by two months of age. Infants practice imitation of other individuals to engage socially and learn new behaviors. In young infants, this involves imitating facial expressions , and imitation of tool use takes place within the first year. Communication develops over the first year, and infants begin using gestures to communicate intention around nine to ten months of age. Verbal communication develops more gradually, taking form during the second year of age.
Children develop fine motor skills shortly after infancy, in the range of three to six years of age, allowing them to engage in behaviors using the hands and eye–hand coordination and perform basic activities of self sufficiency . Children begin expressing more complex emotions in the three- to six-year-old range, including humor, empathy, and altruism, as well engaging in creativity and inquiry. Aggressive behaviors also become varied at this age as children engage in increased physical aggression before learning to favor diplomacy over aggression. Children at this age can express themselves using language with basic grammar. As children grow older, they develop emotional intelligence . Young children engage in basic social behaviors with peers , typically forming friendships centered on play with individuals of the same age and gender. Behaviors of young children are centered around play, which allows them to practice physical, cognitive, and social behaviors. Basic self-concept first develops as children grow, particularly centered around traits such as gender and ethnicity, and behavior is heavily affected by peers for the first time.
Adolescents undergo changes in behavior caused by puberty and the associated changes in hormone production. Production of testosterone increases sensation seeking and sensitivity to rewards in adolescents as well as aggression and risk-taking in adolescent boys. Production of estradiol causes similar risk-taking behavior among adolescent girls. The new hormones cause changes in emotional processing that allow for close friendships, stronger motivations and intentions, and adolescent sexuality . Adolescents undergo social changes on a large scale, developing a full self-concept and making autonomous decisions independently of adults. They typically become more aware of social norms and social cues than children, causing an increase in self-consciousness and adolescent egocentrism that guides behavior in social settings throughout adolescence.
Human brains, as with those of all mammals, are neuroplastic . This means that the structure of the brain changes over time as neural pathways are altered in response to the environment. Many behaviors are learned through interaction with others during early development of the brain. Human behavior is distinct from the behavior of other animals in that it is heavily influenced by culture and language. Social learning allows humans to develop new behaviors by following the example of others. Culture is also the guiding influence that defines social norms.
Physical disabilities can prevent individuals from engaging in typical human behavior or necessitate alternative behaviors. Accommodations and accessibility are often made available for individuals with physical disabilities in developed nations, including health care, assistive technology , and vocational services . Severe disabilities are associated with increased leisure time but also with a lower satisfaction in the quality of leisure time. Productivity and health both commonly undergo long term decline following the onset of a severe disability. Mental disabilities are those that directly affect cognitive and social behavior. Common mental disorders include mood disorders , anxiety disorders , personality disorders , and substance dependence .
^ Longino 2013 , pp. 13–14. ^ Longino 2013 , pp. 7–8. ^ Longino 2013 , p. 2. ^ Longino 2013 , p. 11. ^ Longino 2013 , p. 1. ^ Longino 2013 , p. 8. ^ Longino 2013 , pp. 9–10. ^ Longino 2013 , p. 12. ^ Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 . ^ Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 . ^ Duck 2007 , pp. 1–5. ^ Duck 2007 , pp. 10–14. ^ Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 . ^ Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 . ^ Goode 2015 , pp. 3–4. ^ Goode 2015 , p. 7. ^ Goode 2015 , p. 5. ^ Goode 2015 , p. 6. ^ Duck 2007 , p. 107. ^ Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 . ^ Duck 2007 , pp. 56–60. ^ Duck 2007 , pp. 121–125. ^ Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 . ^ Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 . ^ Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 . ^ Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation. ^ Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 . ^ Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 . ^ Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 . ^ Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 . ^ Evans 2003 , pp. 1–21. ^ Evans 2003 , pp. 47–. ^ Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 . ^ Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 . ^ " 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 . ^ Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 . ^ Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 . ^ Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 . ^ McKeown, Thomas (1980). The Role of Medicine . Princeton University Press. p. 78. ISBN 978-1400854622 . ^ Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 . ^ Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 . ^ Baggott, L. M. (1997). Human Reproduction . Cambridge University Press. p. 5. ISBN 978-0521469142 . ^ Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 . ^ Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 . ^ Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 . ^ Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 . ^ Neff 1985 , pp. 24–33. ^ Neff 1985 , pp. 41–46. ^ Neff 1985 , p. 2. ^ Neff 1985 , pp. 142–153. ^ Neff 1985 , pp. 79–80. ^ Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 . ^ Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 . ^ Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X . ^ Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 . ^ Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 . ^ Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 . ^ Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 . ^ Bremner & Wachs 2010 , pp. 234–235. ^ Bremner & Wachs 2010 , pp. 264–265. ^ Bremner & Wachs 2010 , pp. 337–340. ^ Bremner & Wachs 2010 , pp. 346–347. ^ Bremner & Wachs 2010 , pp. 398–399. ^ Woody & Woody 2019 , pp. 259–260. ^ Woody & Woody 2019 , p. 263. ^ Woody & Woody 2019 , p. 279. ^ Woody & Woody 2019 , pp. 268–269. ^ Charlesworth 2019 , p. 346. ^ Woody & Woody 2019 , p. 281. ^ Woody & Woody 2019 , p. 290. ^ Charlesworth 2019 , p. 343. ^ Charlesworth 2019 , p. 353. ^ Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 . ^ Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 . ^ Van Schaik 2016 , Chapter 2.4. ^ Van Schaik 2016 , Chapter 3.1. ^ Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 . ^ Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 . ^ Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 .
^ Longino 2013 , pp. 13–14. ^ Longino 2013 , pp. 7–8. ^ Longino 2013 , p. 2. ^ Longino 2013 , p. 11. ^ Longino 2013 , p. 1. ^ Longino 2013 , p. 8. ^ Longino 2013 , pp. 9–10. ^ Longino 2013 , p. 12. ^ Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 . ^ Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 . ^ Duck 2007 , pp. 1–5. ^ Duck 2007 , pp. 10–14. ^ Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 . ^ Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 . ^ Goode 2015 , pp. 3–4. ^ Goode 2015 , p. 7. ^ Goode 2015 , p. 5. ^ Goode 2015 , p. 6. ^ Duck 2007 , p. 107. ^ Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 . ^ Duck 2007 , pp. 56–60. ^ Duck 2007 , pp. 121–125. ^ Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 . ^ Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 . ^ Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 . ^ Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation. ^ Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 . ^ Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 . ^ Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 . ^ Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 . ^ Evans 2003 , pp. 1–21. ^ Evans 2003 , pp. 47–. ^ Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 . ^ Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 . ^ Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 . ^ " 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 . ^ Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 . ^ Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 . ^ Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 . ^ McKeown, Thomas (1980). The Role of Medicine . Princeton University Press. p. 78. ISBN 978-1400854622 . ^ Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 . ^ Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 . ^ Baggott, L. M. (1997). Human Reproduction . Cambridge University Press. p. 5. ISBN 978-0521469142 . ^ Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 . ^ Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 . ^ Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 . ^ Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 . ^ Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 . ^ Neff 1985 , pp. 24–33. ^ Neff 1985 , pp. 41–46. ^ Neff 1985 , p. 2. ^ Neff 1985 , pp. 142–153. ^ Neff 1985 , pp. 79–80. ^ Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 . ^ Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 . ^ de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 . ^ Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X . ^ Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 . ^ Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 . ^ Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 . ^ Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 . ^ Bremner & Wachs 2010 , pp. 234–235. ^ Bremner & Wachs 2010 , pp. 264–265. ^ Bremner & Wachs 2010 , pp. 337–340. ^ Bremner & Wachs 2010 , pp. 346–347. ^ Bremner & Wachs 2010 , pp. 398–399. ^ Woody & Woody 2019 , pp. 259–260. ^ Woody & Woody 2019 , p. 263. ^ Woody & Woody 2019 , p. 279. ^ Woody & Woody 2019 , pp. 268–269. ^ Charlesworth 2019 , p. 346. ^ Woody & Woody 2019 , p. 281. ^ Woody & Woody 2019 , p. 290. ^ Charlesworth 2019 , p. 343. ^ Charlesworth 2019 , p. 353. ^ Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 . ^ Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 . ^ Van Schaik 2016 , Chapter 2.4. ^ Van Schaik 2016 , Chapter 3.1. ^ Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 . ^ Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 . ^ Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 .
Boomsma, Dorret; Busjahn, Andreas; Peltonen, Leena (2002). "Classical twin studies and beyond" . Nature Reviews Genetics . 3 (11): 872–882. doi : 10.1038/nrg932 . ISSN 1471-0064 . PMID 12415317 . S2CID 9318812 .
Levinson, Stephen C.; Enfield, Nicholas J. (2006). Roots of Human Sociality . Routledge. pp. 1–3. doi : 10.4324/9781003135517 . ISBN 978-1003135517 . S2CID 150799476 .
Young, H. Peyton (2015-08-01). "The Evolution of Social Norms" . Annual Review of Economics . 7 (1): 359–387. doi : 10.1146/annurev-economics-080614-115322 . ISSN 1941-1383 .
Ayala, Francisco J. (2010-05-11). "The difference of being human: Morality" . Proceedings of the National Academy of Sciences . 107 (supplement_2): 9015–9022. doi : 10.1073/pnas.0914616107 . ISSN 0027-8424 . PMC 3024030 . PMID 20445091 .
Argyle, Michael; Lu, Luo (1990-01-01). "The happiness of extraverts" . Personality and Individual Differences . 11 (10): 1011–1017. doi : 10.1016/0191-8869(90)90128-E . ISSN 0191-8869 .
Geary, David C.; Flinn, Mark V. (2001). "Evolution of Human Parental Behavior and the Human Family" . Parenting . 1 (1–2): 5–61. doi : 10.1080/15295192.2001.9681209 . ISSN 1529-5192 . S2CID 15440367 .
Alford, John R.; Hibbing, John R. (2004). "The Origin of Politics: An Evolutionary Theory of Political Behavior" . Perspectives on Politics . 2 (4): 707–723. doi : 10.1017/S1537592704040460 . ISSN 1541-0986 . S2CID 8341131 . Archived from the original on 2022-05-03 . Retrieved 2022-08-15 .
Barki, Henri; Hartwick, Jon (2004-03-01). "Conceptualizing the Construct of Interpersonal Conflict" . International Journal of Conflict Management . 15 (3): 216–244. doi : 10.1108/eb022913 . ISSN 1044-4068 . Archived from the original on 2022-06-16 . Retrieved 2022-08-14 .
Mitchell, Christopher R. (2005). "Conflict, Social Change and Conflict Resolution. An Enquiry.". Berghof Handbook for Conflict Transformation . Berghof Foundation.
Tomasello, Michael; Rakoczy, Hannes (2003). "What Makes Human Cognition Unique? From Individual to Shared to Collective Intentionality" . Mind and Language . 18 (2): 121–147. doi : 10.1111/1468-0017.00217 . ISSN 0268-1064 . Archived from the original on 2022-08-12 . Retrieved 2022-08-12 .
Colagè, Ivan; d'Errico, Francesco (2020). "Culture: The Driving Force of Human Cognition" . Topics in Cognitive Science . 12 (2): 654–672. doi : 10.1111/tops.12372 . ISSN 1756-8757 . PMID 30033618 . S2CID 51706960 .
Wood, Wendy; Rünger, Dennis (2016-01-04). "Psychology of Habit" . Annual Review of Psychology . 67 (1): 289–314. doi : 10.1146/annurev-psych-122414-033417 . ISSN 0066-4308 . PMID 26361052 . S2CID 8821136 .
Evans, Jonathan St.B. T.; Newstead, Stephen E.; Byrne, Ruth M. J. (2019). "Introduction". Human Reasoning: The Psychology of Deduction . Taylor & Francis. ISBN 978-1317716266 .
Runco, Mark A. (2018). Sternberg, Robert J.; Kaufman, James C. (eds.). The Nature of Human Creativity . Cambridge University Press. pp. 246–263. doi : 10.1017/9781108185936.018 . ISBN 978-1108185936 .
Simon, Herbert A. (2001). "Creativity in the Arts and the Sciences" . The Kenyon Review . 23 (2): 203–220. ISSN 0163-075X . JSTOR 4338222 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 .
Sosis, Richard; Alcorta, Candace (2003-11-24). "Signaling, solidarity, and the sacred: The evolution of religious behavior" . Evolutionary Anthropology: Issues, News, and Reviews . 12 (6): 264–274. doi : 10.1002/evan.10120 . S2CID 443130 . Archived from the original on 2022-08-14 . Retrieved 2022-08-14 .
Cornwall, Marie (1989). "The Determinants of Religious Behavior: A Theoretical Model and Empirical Test" . Social Forces . 68 (2): 572–592. doi : 10.2307/2579261 . JSTOR 2579261 . Archived from the original on 2021-11-03 . Retrieved 2022-08-14 .
" 'How religious commitment varies by country among people of all ages" . Pew Forum on Religion & Public Life . 13 June 2018. Archived from the original on 27 August 2018 . Retrieved 9 March 2019 .
Mann, Jim; Truswell, A. Stewart, eds. (2012). Essentials of Human Nutrition (4th ed.). Oxford: Oxford University Press. p. 1. ISBN 978-0199566341 .
Jewitt, Sarah (2011). "Geographies of shit: Spatial and temporal variations in attitudes towards human waste" . Progress in Human Geography . 35 (5): 608–626. doi : 10.1177/0309132510394704 . ISSN 0309-1325 . S2CID 129647616 . Archived from the original on 2022-05-06 . Retrieved 2022-08-11 .
Gillberg, M. (1997). "Human sleep/wake regulation" . Acta Anaesthesiologica Scandinavica. Supplementum . 110 : 8–10. doi : 10.1111/j.1399-6576.1997.tb05482.x . ISSN 0515-2720 . PMID 9248514 . S2CID 9354406 . Archived from the original on 2022-08-11 . Retrieved 2022-08-11 .
Vina, J.; Sanchis-Gomar, F.; Martinez-Bello, V.; Gomez-Cabrera, M.C. (2012). "Exercise acts as a drug; the pharmacological benefits of exercise: Exercise acts as a drug" . British Journal of Pharmacology . 167 (1): 1–12. doi : 10.1111/j.1476-5381.2012.01970.x . PMC 3448908 . PMID 22486393 .
Curtis, Valerie A. (2007). "A Natural History of Hygiene" . Canadian Journal of Infectious Diseases and Medical Microbiology . 18 (1): 11–14. doi : 10.1155/2007/749190 . ISSN 1712-9532 . PMC 2542893 . PMID 18923689 .
Newson, Lesley (2013). "Cultural Evolution and Human Reproductive Behavior". In Clancy, Kathryn B. H.; Hinde, Katie; Rutherford, Julienne N. (eds.). Building Babies: Primate Development in Proximate and Ultimate Perspective . New York: Springer. p. 487. ISBN 978-1461440604 . OCLC 809201501 .
Jones, Richard E.; Lopez, Kristin H. (2013). Human Reproductive Biology . Academic Press. p. 63. ISBN 978-0123821850 .
Inman, Verne T. (1966-05-14). "Human Locomotion" . Canadian Medical Association Journal . 94 (20): 1047–1054. ISSN 0008-4409 . PMC 1935424 . PMID 5942660 .
Carrier, David R.; Kapoor, A. K.; Kimura, Tasuku; Nickels, Martin K.; Scott, Eugenie C.; So, Joseph K.; Trinkaus, Erik (1984-08-01). "The Energetic Paradox of Human Running and Hominid Evolution [and Comments and Reply]" . Current Anthropology . 25 (4): 483–495. doi : 10.1086/203165 . ISSN 0011-3204 . S2CID 15432016 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 .
Wells, Richard; Greig, Michael (2001-12-01). "Characterizing human hand prehensile strength by force and moment wrench" . Ergonomics . 44 (15): 1392–1402. doi : 10.1080/00140130110109702 . ISSN 0014-0139 . PMID 11936830 . S2CID 10935674 . Archived from the original on 2022-08-25 . Retrieved 2022-08-23 .
Santos, Laurie R; Hughes, Kelly D (2009-02-01). "Economic cognition in humans and animals: the search for core mechanisms" . Current Opinion in Neurobiology . Cognitive neuroscience. 19 (1): 63–66. doi : 10.1016/j.conb.2009.05.005 . ISSN 0959-4388 . PMID 19541475 . S2CID 21443957 .
Stebbins, Robert A. (2001-01-01). "The costs and benefits of hedonism: some consequences of taking casual leisure seriously" . Leisure Studies . 20 (4): 305–309. doi : 10.1080/02614360110086561 . ISSN 0261-4367 . S2CID 145273350 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 .
Caldwell, Linda L. (2005-02-01). "Leisure and health: why is leisure therapeutic?" . British Journal of Guidance & Counselling . 33 (1): 7–26. doi : 10.1080/03069880412331335939 . ISSN 0306-9885 . S2CID 144193642 .
Stebbins, Robert A. (2001). "Serious Leisure" . Society . 38 (4): 53–57. doi : 10.1007/s12115-001-1023-8 . Archived from the original on 2022-08-25 . Retrieved 2022-08-14 .
de Vries, Jan (2008). The Industrious Revolution: Consumer Behavior and the Household Economy, 1650 to the Present . Cambridge University Press. pp. 4–7. ISBN 978-0511409936 .
Gajjar, Nilesh B. (2013). "Factors Affecting Consumer Behavior". International Journal of Research in Health Science . 1 (2): 10–15. ISSN 2320-771X .
Steiner, F. (2008). "Human Ecology: Overview". In Jørgensen, Sven Erik; Fath, Brian D. (eds.). Encyclopedia of Ecology . Elsevier. pp. 1898–1906. doi : 10.1016/B978-008045405-4.00626-1 . ISBN 978-0080454054 . OCLC 256490644 .
Hosey, Geoff; Melfi, Vicky (2014). "Human-animal interactions, relationships and bonds: a review and analysis of the literature" . International Journal of Comparative Psychology . 27 (1). ISSN 0889-3675 .
Plomin, Robert; DeFries, John C.; McClearn, Gerald E. (2008). "Overview". Behavioral Genetics (5th ed.). Worth Publishers. pp. 1–4. ISBN 978-1429205771 .
Beauchaine, T. P.; Hinshaw, S. P.; Gatzke-Kopp, L. (2008). "Genetic and Environmental Influences on Behavior". Child and Adolescent Psychopathology . Wiley. pp. 58–90. ISBN 978-0470007440 .
Peper, Jiska S.; Dahl, Ronald E. (2013). "The Teenage Brain: Surging Hormones – Brain-Behavior Interactions During Puberty" . Current Directions in Psychological Science . 22 (2): 134–139. doi : 10.1177/0963721412473755 . ISSN 0963-7214 . PMC 4539143 . PMID 26290625 .
Choudhury, Suparna; Blakemore, Sarah-Jayne; Charman, Tony (2006). "Social cognitive development during adolescence" . Social Cognitive and Affective Neuroscience . 1 (3): 165–174. doi : 10.1093/scan/nsl024 . PMC 2555426 . PMID 18985103 .
Lutz, Barbara J.; Bowers, Barbara J. (2005). "Disability in Everyday Life" . Qualitative Health Research . 15 (8): 1037–1054. doi : 10.1177/1049732305278631 . ISSN 1049-7323 . PMID 16221878 . S2CID 24307046 .
Powdthavee, Nattavudh (2009-12-01). "What happens to people before and after disability? Focusing effects, lead effects, and adaptation in different areas of life" . Social Science & Medicine . Part Special Issue: New approaches to researching patient safety. 69 (12): 1834–1844. doi : 10.1016/j.socscimed.2009.09.023 . ISSN 0277-9536 . PMID 19833424 .
Krueger, Robert F. (1999-10-01). "The Structure of Common Mental Disorders" . Archives of General Psychiatry . 56 (10): 921–926. doi : 10.1001/archpsyc.56.10.921 . ISSN 0003-990X . PMID 10530634 .
Authority control databases International FAST National France BnF data Israel United States Japan Czech Republic Other NARA
Categories : Human behavior Behavior Culture Humans Main topic articles Hidden categories: Articles with short description Short description is different from Wikidata Use American English from February 2020 All Wikipedia articles written in American English CS1: long volume value CS1 maint: DOI inactive as of January 2024 Commons category link is on Wikidata Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with J9U identifiers Articles with LCCN identifiers Articles with NDL identifiers Articles with NKC identifiers Articles with NARA identifiers
Hidden categories: Articles with short description Short description is different from Wikidata Use American English from February 2020 All Wikipedia articles written in American English CS1: long volume value CS1 maint: DOI inactive as of January 2024 Commons category link is on Wikidata Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with J9U identifiers Articles with LCCN identifiers Articles with NDL identifiers Articles with NKC identifiers Articles with NARA identifiers
This page was last edited on 23 March 2024, at 06:25 (UTC) . Text is available under the Creative Commons Attribution-ShareAlike License 4.0 ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy . Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. , a non-profit organization. Privacy policy About Wikipedia Disclaimers Contact Wikipedia Code of Conduct Developers Statistics Cookie statement Mobile view | biology | 929254 | https://sv.wikipedia.org/wiki/Sociobiologi | Sociobiologi | Sociobiologi eller socialbiologi är en evolutionärt inriktad syntes av vetenskapliga discipliner som försöker förklara socialt beteende inom alla arter genom att undersöka de evolutionära fördelar som beteendet kan ge. Det betraktas ofta som en gren av biologi och sociologi, och drar således även insikter från etologi, antropologi, evolution, zoologi, arkeologi, populationsgenetik och andra discipliner. Inom studiet av mänskliga samhällen är sociobiologi nära relaterat till humanekologi och evolutionspsykologi. Under senare tid har begreppet sociobiologi mer eller mindre övergått till evolutionspsykologi.
Sociobiologin studerar djurens beteende (inklusive människans), vilka evolutionära fördelar olika beteenden har och vilken selektion som gör att dessa beteenden sprider sig. Sociobiologin introducerades via en inflytelserik bok av biologen E. O. Wilson år 1975. Generellt hävdar företrädarna att det finns en genetisk bakgrund till många beteenden. Begreppet släktskapsselektion introducerades på bred front av företrädarna för denna skola.
Kända sociobiologer
Pierre van den Berghe
Richard Dawkins
Daniel Dennett
Edward O. Wilson
W. D. Hamilton
J. P. Rushton
George C. Williams
John Maynard Smith
Sarah Blaffer Hrdy
Richard Machalek
Steven Pinker
Kritik
Kritiken mot sociobiologin riktar sig främst in på att peka på kopplingen mellan sociobiologi och biologisk determinism; att olikheter mellan människor beror på specifika genetiska orsaker snarare än skillnader sprungna ur kulturella och sociala miljöer. Kritikerna menar att den biologiska determinismen var en grundläggande ideologisk och filosofisk förutsättning för socialdarwinismen, de rashygienrörelser som verkade under 1900-talet, samt kontroverser runt intelligenstester.
Se även
Evolution
Psykologi
Evolutionspsykologi
Humanekologi
Kulturell evolution
Socialt beteende
Vidare läsning
Sociobiology: The New Synthesis av E. O. Wilson, 1975
Ett oskrivet blad av Steven Pinker
Den själviska genen (The Selfish Gene) av Richard Dawkins
Biology, Ideology and Human Nature: Not In Our Genes av Richard Lewontin, Steven Rose & Leon Kamin
Alcock, John (2001). The Triumph of Sociobiology. Oxford: Oxford University Press.
Barkow, Jerome (Ed.). (2006) Missing the Revolution: Darwinism for Social Scientists. Oxford: Oxford University Press.
Cronin, H. (1992). The Ant and the Peacock: Altruism and Sexual Selection from Darwin to Today. Cambridge: Cambridge University Press.
Richards, Janet Radcliffe (2000). Human Nature After Darwin: A Philosophical Introduction. London: Routledge.
Referenser
Externa länkar
Sociobiology (Stanford Encyclopedia of Philosophy) - Harmon Holcomb & Jason Byron
Speak, Darwinists! Intervjuer med ledande sociobiologer.
Race and Creation - Richard Dawkins
Genetic Similarity and Ethnic Nationalism - Ett försök till förklaring av politisk gruppformering från sociobiologiskt perspektiv
En kort historia över sociobiologin - New York Times
Evolution
Sociologi
Biologi | swedish | 0.573603 |
human_monogamy/Human.txt |
Main menu Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file Search Search Create account Log in Personal tools Create account Log in Pages for logged out editors learn more Contributions Talk
Main menu Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Main menu Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Main menu move to sidebar hide Navigation Main page Contents Current events Random article About Wikipedia Contact us Donate Contribute Help Learn to edit Community portal Recent changes Upload file
Search Search Create account Log in Personal tools Create account Log in Pages for logged out editors learn more Contributions Talk
Contents move to sidebar hide (Top) 1 Etymology and definition 2 Evolution 3 History Toggle History subsection 3.1 Prehistory 3.2 Ancient 3.3 Medieval 3.4 Modern 3.5 Contemporary 4 Habitat and population 5 Biology Toggle Biology subsection 5.1 Anatomy and physiology 5.2 Genetics 5.3 Life cycle 5.4 Diet 5.5 Biological variation 6 Psychology Toggle Psychology subsection 6.1 Sleep and dreaming 6.2 Consciousness and thought 6.3 Motivation and emotion 6.4 Sexuality and love 7 Culture Toggle Culture subsection 7.1 Language 7.2 The arts 7.3 Tools and technologies 7.4 Religion and spirituality 7.5 Science and philosophy 8 Society Toggle Society subsection 8.1 Gender 8.2 Kinship 8.3 Ethnicity 8.4 Government and politics 8.5 Trade and economics 8.6 Conflict 9 See also 10 Notes 11 References 12 External links Toggle the table of contents Human 213 languages Afrikaans Alemannisch አማርኛ अंगिका العربية Aragonés ܐܪܡܝܐ Armãneashti অসমীয়া Asturianu Atikamekw अवधी Avañe'ẽ Авар Aymar aru Azərbaycanca تۆرکجه Basa Bali বাংলা Banjar 閩南語 / Bân-lâm-gú Basa Banyumasan Башҡортса Беларуская Беларуская (тарашкевіца) भोजपुरी Bikol Central Български Boarisch བོད་ཡིག Bosanski Brezhoneg Буряад Català Чӑвашла Cebuano Čeština ChiShona ChiTumbuka Corsu Cymraeg Dagbanli Dansk الدارجة Davvisámegiella Deutsch डोटेली Eesti Ελληνικά Эрзянь Español Esperanto Euskara فارسی Fiji Hindi Føroyskt Frysk Furlan Gaeilge Gàidhlig Galego ГӀалгӀай 贛語 گیلکی ગુજરાતી 客家語/Hak-kâ-ngî 한국어 Hausa Հայերեն हिन्दी Hrvatski Ido Igbo Ilokano Bahasa Indonesia ᐃᓄᒃᑎᑐᑦ / inuktitut Ирон IsiXhosa IsiZulu Íslenska עברית Jawa ಕನ್ನಡ Kapampangan ქართული कॉशुर / کٲشُر Қазақша Kernowek Kiswahili Коми Kongo Kreyòl ayisyen Kriyòl gwiyannen Kurdî Кыргызча Ladin Лакку ລາວ Latgaļu Latina Latviešu Лезги Lietuvių Ligure Limburgs Lingála Lingua Franca Nova La .lojban. Luganda Magyar मैथिली Македонски Malagasy മലയാളം Malti मराठी მარგალური مصرى مازِرونی Bahasa Melayu ꯃꯤꯇꯩ ꯂꯣꯟ Minangkabau 閩東語 / Mìng-dĕ̤ng-ngṳ̄ Mirandés Мокшень Монгол မြန်မာဘာသာ Nāhuatl Nederlands Nedersaksies नेपाली नेपाल भाषा 日本語 Нохчийн Nordfriisk Norfuk / Pitkern Norsk bokmål Norsk nynorsk Occitan Олык марий ଓଡ଼ିଆ Oʻzbekcha / ўзбекча ਪੰਜਾਬੀ पालि پنجابی Papiamentu پښتو Patois Перем коми ភាសាខ្មែរ Piemontèis Plattdüütsch Polski Português Qaraqalpaqsha Ripoarisch Română Romani čhib Rumantsch Runa Simi Русский Саха тыла Sakizaya संस्कृतम् ᱥᱟᱱᱛᱟᱲᱤ Scots Shqip Sicilianu සිංහල Simple English سنڌي Slovenčina Slovenščina Ślůnski Soomaaliga کوردی Српски / srpski Srpskohrvatski / српскохрватски Sunda Suomi Svenska Tagalog தமிழ் Taclḥit Taqbaylit Татарча / tatarça Tayal తెలుగు ไทย Тоҷикӣ Türkçe Türkmençe Twi Tyap Українська اردو ئۇيغۇرچە / Uyghurche Vahcuengh Vepsän kel’ Tiếng Việt Võro Walon 文言 West-Vlams Winaray 吴语 Xitsonga ייִדיש Yorùbá 粵語 Zazaki Žemaitėška 中文 Edit links Article Talk English Read View source View history Tools Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote From Wikipedia, the free encyclopedia Species of hominid in the genus Homo Several terms redirect here. For other uses, see Human (disambiguation) , Mankind (disambiguation) , Humankind (disambiguation) , Human Race (disambiguation) , Human Being (disambiguation) , and Homo sapiens (disambiguation) . Human Temporal range: 0.3–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Chibanian – present Male (left) and female (right) adult humans, Thailand , 2007 Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Infraorder: Simiiformes Family: Hominidae Subfamily: Homininae Tribe: Hominini Genus: Homo Species: H. sapiens Binomial name Homo sapiens Linnaeus , 1758 Homo sapiens population density (2005) Humans ( Homo sapiens ) or modern humans are the most common and widespread species of primate , and the last surviving species of the genus Homo . They are great apes characterized by their hairlessness , bipedalism , and high intelligence . Humans have large brains , enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools , and form complex social structures and civilizations . Humans are highly social , with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states . As such, social interactions between humans have established a wide variety of values, social norms , languages , and traditions (collectively termed institutions ), each of which bolsters human society . Humans are also highly curious : the desire to understand and influence phenomena has motivated humanity's development of science , technology , philosophy , mythology , religion , and other frameworks of knowledge ; humans also study themselves through such domains as anthropology , social science , history , psychology , and medicine . As of April 2024, there are estimated to be more than 8 billion humans alive . Although some scientists equate the term "humans" with all members of the genus Homo , in common usage it generally refers to Homo sapiens , the only extant member. All other members of the genus Homo , which are now extinct, are known as archaic humans , and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa , they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence , interbreeding with Homo sapiens , or inability to adapt to climate change. For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution , which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement ; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change . Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle. Genes and the environment influence human biological variation in visible characteristics, physiology , disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic : generally, males have greater body strength and females have a higher body fat percentage. At puberty , humans develop secondary sex characteristics . Females are capable of pregnancy , usually between puberty, at around 12 years old, and menopause , around the age of 50. Humans are omnivorous , capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus . Humans can survive for up to eight weeks without food and several days without water . Humans are generally diurnal , sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death . Often, both the mother and the father provide care for their children, who are helpless at birth . Humans have a large, highly developed, and complex prefrontal cortex , the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory ; they have flexible facial expressions, self-awareness , and a theory of mind . The human mind is capable of introspection , private thought , imagination , volition , and forming views on existence . This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language . Etymology and definition Further information: Names for the human species and Human taxonomy Carl Linnaeus coined the name Homo sapiens All modern humans are classified into the species Homo sapiens , coined by Carl Linnaeus in his 1735 work Systema Naturae . The generic name " Homo " is a learned 18th-century derivation from Latin homō , which refers to humans of either sex. The word human can refer to all members of the Homo genus. The name " Homo sapiens " means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals , should be included as a separate species of humans or as a subspecies of H. sapiens . Human is a loanword of Middle English from Old French humain , ultimately from Latin hūmānus , the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity ) as well as to human males. It may also refer to individuals of either sex. Despite the fact that the word animal is colloquially used as an antonym for human , and contrary to a common biological misconception , humans are animals. The word person is often used interchangeably with human , but philosophical debate exists as to whether personhood applies to all humans or all sentient beings , and further if one can lose personhood (such as by going into a persistent vegetative state ). Evolution Main article: Human evolution Humans are apes ( superfamily Hominoidea ). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo ), then gorillas (genus Gorilla ), and finally, chimpanzees and bonobos (genus Pan ). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct. Reconstruction of Lucy , the first Australopithecus afarensis skeleton found The genus Homo evolved from Australopithecus . Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus . The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia , and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster ) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan . Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis , the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier. The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second ( Southern Dispersal ) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii , Easter Island , Madagascar , and New Zealand in the years 300 to 1280 CE. Human evolution was not a simple linear or branched progression but involved interbreeding between related species . Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans , may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans. Human evolution is characterized by a number of morphological , developmental , physiological , and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees . The most significant of these adaptations are hairlessness , obligate bipedalism, increased brain size and decreased sexual dimorphism ( neoteny ). The relationship between all these changes is the subject of ongoing debate. Hominoidea (hominoids, apes ) Hylobatidae ( gibbons ) Hominidae (hominids, great apes ) Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans) History Main article: Human history Prehistory Main article: Prehistory Overview map of the peopling of the world by early human migration during the Upper Paleolithic , following the Southern Dispersal paradigm Until about 12,000 years ago, all humans lived as hunter-gatherers . The Neolithic Revolution (the invention of agriculture ) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea , and the Sahel and West Savanna regions of Africa. Access to food surplus led to the formation of permanent human settlements , the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations . Ancient Main article: Ancient history Great Pyramids of Giza , Egypt An urban revolution took place in the 4th millennium BCE with the development of city-states , particularly Sumerian cities located in Mesopotamia . It was in these cities that the earliest known form of writing, cuneiform script , appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation . They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture , Minoans and the Shang dynasty , rose to prominence in new areas. The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages . During this period iron started replacing bronze, leading to the Iron Age . In the 5th century BCE, history started being recorded as a discipline , which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars . In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire 's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions. Medieval Main article: Post-classical history Medieval French manuscript illustration of the three classes of medieval society from the 13th-century Li Livres dou Santé Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages . During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age , inspiring achievements in architecture , the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England , the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims . In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast . Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific. Modern Main articles: Early modern period and Late modern period James Watt 's steam engine The early modern period in Europe and the Near East ( c. 1450 –1800) began with the final defeat of the Byzantine Empire , and the rise of the Ottoman Empire . Meanwhile, Japan entered the Edo period , the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance , starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas . This expansion led to the Atlantic slave trade and the genocide of Native American peoples . This period also marked the Scientific Revolution , with great advances in mathematics , mechanics , astronomy and physiology . The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology , major innovations in transport and energy development . The United States of America underwent great change, going from a small group of colonies to one of the global superpowers . The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World , while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania. A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War , one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War , involving almost all of the world's countries . The war's destruction led to the collapse of most global empires, leading to widespread decolonization. Contemporary Main article: Contemporary history Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race , ending in the collapse of the Soviet Union. The current Information Age , spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected. Habitat and population Further information: Human geography and Demography Population statistics Choropleth showing Population density (people per square kilometer) estimates by 30 arc-second grid in 2020 World population 8.1 billion Population density 16/km (41/sq mi) by total area 54/km (140/sq mi) by land area Largest cities Tokyo , Delhi , Shanghai , São Paulo , Mexico City , Cairo , Mumbai , Beijing , Dhaka , Osaka , New York - Newark , Karachi , Buenos Aires , Chongqing , Istanbul , Kolkata , Manila , Lagos , Rio de Janeiro , Tianjin , Kinshasa , Guangzhou , Los Angeles - Long Beach - Santa Ana , Moscow , Shenzhen , Lahore , Bangalore , Paris , Jakarta , Chennai , Lima , Bogota , Bangkok , London Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence , such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation , urban planning , construction, deforestation and desertification . Human settlements continue to be vulnerable to natural disasters , especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics , increasing knowledge or enhancing the exchange of resources. Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms , although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa , India , Russia , Australia , Fiji , United States and Brazil (each located in a different biogeographical realm). By using advanced tools and clothing , humans have been able to extend their tolerance to a wide variety of temperatures, humidities , and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest , arid desert , extremely cold arctic regions , and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth 's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%). Within the last century, humans have explored challenging environments such as Antarctica, the deep sea , and outer space . Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific , military , or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft . Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station . Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%. Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues , first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals. In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums . Humans have had a dramatic effect on the environment . They are apex predators , being rarely preyed upon by other species. Human population growth , industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life. Biology Anatomy and physiology Main article: Human body Basic anatomical features of female and male humans. These models have had body hair and male facial hair removed and head hair trimmed. Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.3 2.1.2.3 . Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth . Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars , with some individuals having them congenitally absent. Humans share with chimpanzees a vestigial tail, appendix , flexible shoulder joints, grasping fingers and opposable thumbs . Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling , hearing and digesting proteins . While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair , most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet. It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged . Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals. Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger. Genetics Main article: Human genetics A graphical representation of the standard human karyotype , including both the female (XX) and male (XY) sex chromosomes. Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes , each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes . Like other mammals, humans have an XY sex-determination system , so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood. While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years. The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms . African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas . By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA , which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve , must have lived around 90,000 to 200,000 years ago. Life cycle See also: Childbirth and Life expectancy A 10 mm human embryo at 5 weeks Most human reproduction takes place by internal fertilization via sexual intercourse , but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus . Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions. Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries. Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth , humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy , childhood , adolescence , adulthood and old age . The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis ), rather than by continuing to bear children into old age. The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018 , the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic , it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world , the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide. Human life stages Infant boy and girl Boy and girl before puberty ( children ) Adolescent male and female Adult man and woman Elderly man and woman Diet Main article: Human nutrition Humans living in Bali , Indonesia , preparing a meal Humans are omnivorous , capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous . In some cases, dietary restrictions in humans can lead to deficiency diseases ; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science . Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game , which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus . Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture , a gradual process called the Neolithic Revolution . These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture. In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation . Childhood malnutrition is also common and contributes to the global burden of disease . However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries . Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an " obesity epidemic ." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet. Biological variation Main article: Human genetic variation A Libyan , a Nubian , a Syrian , and an Egyptian , drawing by an unknown artist after a mural of the tomb of Seti I There is biological variation in the human species – with traits such as blood type , genetic diseases , cranial features , facial features , organ systems , eye color , hair color and texture , height and build , and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin , and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet , exercise, and sleep patterns . A variety of human hair colors; from top left, clockwise: black , brown , blonde , white , red . There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk . Sickle cell anemia , which may provide increased resistance to malaria , is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions , tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes . Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau . Human hair ranges in color from red to blond to brown to black , which is the most frequent. Hair color depends on the amount of melanin , with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach , or even nearly white or colorless in cases of albinism . It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D , which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation. There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other. Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa , and particularly West Africa , have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans. Humans are a gonochoric species, meaning they are divided into male and female sexes . The greatest degree of genetic variation exists between males and females . While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation . As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare. Psychology Main article: Psychology Drawing of the human brain , showing several important structures The human brain , the focal point of the central nervous system in humans, controls the peripheral nervous system . In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion , it is also the locus of "higher" order functioning such as thought , reasoning , and abstraction . These cognitive processes constitute the mind , and, along with their behavioral consequences, are studied in the field of psychology . Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition . This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to. There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in " mental time travel ". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind . Sleep and dreaming Main articles: Sleep and Dream Humans are generally diurnal . The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort. During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep . The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming , where the dreamer is self-aware . Dreams can at times make a creative thought occur or give a sense of inspiration . Consciousness and thought Main articles: Consciousness and Cognition Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection , private thought , imagination and volition . It now often includes some kind of experience , cognition , feeling or perception . It may be 'awareness', or ' awareness of awareness ', or self-awareness . There might be different levels or orders of consciousness , or different kinds of consciousness, or just one kind with different features. The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses , and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition , the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development . Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population. Motivation and emotion Main articles: Motivation and Emotion Illustration of grief from Charles Darwin 's 1872 book The Expression of the Emotions in Man and Animals Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization . Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure . They are often intertwined with mood , temperament , personality , disposition , creativity , and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal. Emotional experiences perceived as pleasant , such as joy , interest or contentment , contrast with those perceived as unpleasant , like anxiety , sadness , anger , and despair . Happiness , or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects , while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life . Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted. Sexuality and love Main articles: Human sexuality and Love Human parents often display familial love for their children. For humans, sexuality involves biological , erotic , physical , emotional , social , or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions , including the human sexual response cycle . Sexuality also affects and is affected by cultural, political, legal, philosophical, moral , ethical , and religious aspects of life. Sexual desire, or libido , is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often. Humans can fall anywhere along a continuous scale of sexual orientation , although most humans are heterosexual . While homosexual behavior occurs in some other animals , only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation , as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well. Love most commonly refers to a feeling of strong attraction or emotional attachment . It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine , norepinephrine , serotonin and other chemicals stimulate the brain's pleasure center , leading to side effects such as increased heart rate , loss of appetite and sleep , and an intense feeling of excitement . Culture Main articles: Culture and Cultural universal Human society statistics Most widely spoken languages English , Mandarin Chinese , Hindi , Spanish , Standard Arabic , Bengali , French , Russian , Portuguese , Urdu Most practiced religions Christianity , Islam , Hinduism , Buddhism , folk religions , Sikhism , Judaism , unaffiliated Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the " folk physics " required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning . Language Main article: Language Principal language families of the world (and in some cases geographic groups of families). For greater detail, see Distribution of languages in the world . While many species communicate , language is unique to humans, a defining feature of humanity, and a cultural universal . Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement , using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors. Language differs from other forms of communication in that it is modality independent ; the same meanings can be conveyed through different media, audibly in speech , visually by sign language or writing, and through tactile media such as braille . Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct . The arts Main article: The arts Human arts can take many forms including visual , literary , and performing . Visual art can range from paintings and sculptures to film , fashion design , and architecture . Literary arts can include prose , poetry , and dramas . The performing arts generally involve theatre , music , and dance . Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation , video games , and medicine . As well as providing entertainment and transferring knowledge, the arts are also used for political purposes . The Deluge tablet of the Gilgamesh epic in Akkadian Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage. Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures . There exists a wide variety of music genres and ethnic musics ; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment . Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain. Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh , first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation. Tools and technologies Main articles: Tool and Technology The SCMaglev , the fastest train in the world clocking in at 603 km/h (375 mph) as of 2015 Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated , thus proving essential in the development of agriculture – what is known as the Neolithic Revolution . China developed paper , the printing press , gunpowder , the compass and other important inventions . The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel , which is used in railways , skyscrapers and many other products. This coincided with the Industrial Revolution , where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially , with major innovations in the 20th century including: electricity , penicillin , semiconductors , internal combustion engines , the Internet , nitrogen fixing fertilisers , airplanes , computers , automobiles , contraceptive pills , nuclear fission , the green revolution , radio , scientific plant breeding , rockets , air conditioning , television and the assembly line . Religion and spirituality Main articles: Religion and Spirituality Shango , the Orisha of fire, lightning, and thunder, in the Yoruba religion , depicted on horseback Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural , sacred or divine , and practices, values , institutions and rituals associated with such belief. Some religions also have a moral code . The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago ). It may have evolved to play a role in helping enforce and encourage cooperation between humans. Religion manifests in diverse forms. Religion can include a belief in life after death , the origin of life , the nature of the universe ( religious cosmology ) and its ultimate fate ( eschatology ), and moral or ethical teachings . Views on transcendence and immanence vary substantially; traditions variously espouse monism , deism , pantheism , and theism (including polytheism and monotheism ). Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims , Hindus and Buddhists . As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious , including those with no religious beliefs or no identity with any religion. Science and philosophy Main articles: Science and Philosophy The Dunhuang map , a star map showing the North Polar region. China circa 700. An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy. Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period . Other early advances in science came from the Han dynasty in China and during the Islamic Golden Age . The scientific revolution , near the end of the Renaissance , led to the emergence of modern science . A chain of events and influences led to the development of the scientific method , a process of observation and experimentation that is used to differentiate science from pseudoscience . An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition . All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics ), which are concerned with formal systems , the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics , chemistry , biology ) and social sciences (e.g., psychology , economics, sociology). Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics , epistemology , logic , and axiology (which includes ethics and aesthetics ). Society Main article: Society Humans often live in family-based social structures Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power , reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies . Gender Main article: Gender Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex . The most common categorisation is a gender binary of men and women . Some societies recognise a third gender , or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female. Gender roles are often associated with a division of norms , practices , dress , behavior , rights , duties , privileges , status , and power , with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct , gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic , while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal. Kinship Main article: Kinship All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants ( consanguinity ), and relations through marriage ( affinity ). There is also a third type applied to godparents or adoptive children ( fictive ). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance . All societies have rules of incest taboo , according to which marriage between certain kinds of kin relations is prohibited, and some also have rules of preferential marriage with certain kin relations. Ethnicity Main article: Ethnic group Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry , language , history , society , culture , nation , religion , or social treatment within their residing area. Ethnicity is separate from the concept of race , which is based on physical characteristics, although both are socially constructed . Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries. Government and politics Main articles: Government and Politics The United Nations headquarters in New York City, which houses one of the world's largest political organizations As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances. Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy , 17% in a hybrid regime , and 37% in an authoritarian regime . Many countries belong to international organizations and alliances ; the largest of these is the United Nations , with 193 member states . Trade and economics Main articles: Trade and Economics The Silk Road (red) and spice trade routes (blue) Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian . The first truly international trade routes were around the spice trade through the Roman and medieval periods. Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities ; the oldest being in the form of cattle and the most widely used being cowrie shells . Money has since evolved into governmental issued coins , paper and electronic money . Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population. Conflict Main article: Conflict (process) American troops landing at Normandy , WWII. Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered , rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations, with rates of homicide about 0.01% in societies that have legal systems and strong cultural attitudes against violence. The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war ) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict. See also Mammals portal Evolutionary biology portal Science portal List of human evolution fossils Timeline of human evolution Notes ^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects. ^ Cities with over 10 million inhabitants as of 2018. ^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that. References ^ Groves CP (2005). Wilson DE , Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4 . OCLC 62265494 . ^ Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences . 149 (1): 109–114. JSTOR 4065043 . ^ Porkorny (1959). IEW . s.v. "g'hðem" pp. 414–116. ^ "Homo" . Dictionary.com Unabridged (v 1.1) . Random House. 23 September 2008. Archived from the original on 27 September 2008. ^ Barras, Colin (11 January 2016). "We don't know which species should be classed as 'human' " . BBC . Archived from the original on 26 August 2021 . Retrieved 31 March 2021 . ^ Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758" . Proceedings of the Academy of Natural Sciences of Philadelphia . 149 : 109–114. ISSN 0097-3157 . JSTOR 4065043 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . ^ OED . s.v. "human". ^ "Man" . Merriam-Webster Dictionary . Archived from the original on 22 September 2017 . Retrieved 14 September 2017 . Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination ^ "Thesaurus results for human" . Merriam-Webster Dictionary . Archived from the original on 28 June 2022 . Retrieved 21 May 2022 . ^ "Misconceptions about evolution – Understanding Evolution" . University of California, Berkeley . 19 September 2021. Archived from the original on 6 June 2022 . Retrieved 21 May 2022 . ^ "Concept of Personhood" . University of Missouri School of Medicine . Archived from the original on 4 March 2021 . Retrieved 4 July 2021 . ^ Tuttle RH (4 October 2018). "Hominoidea: conceptual history" . In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology . Hoboken , New Jersey , United States : John Wiley & Sons, Inc. pp. 1–2. doi : 10.1002/9781118584538.ieba0246 . ISBN 978-1-118-58442-2 . S2CID 240125199 . Retrieved 26 May 2021 . ^ Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution . 30 (3): 260–266. Bibcode : 1990JMolE..30..260G . doi : 10.1007/BF02099995 . PMID 2109087 . S2CID 2112935 . ^ Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets" . Molecular Biology and Evolution . 14 (3): 248–265. doi : 10.1093/oxfordjournals.molbev.a025761 . PMID 9066793 . ^ MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes" . Evolution pages . Archived from the original on 9 August 2011 . Retrieved 18 May 2006 . ^ McNulty, Kieran P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?" . Nature Education Knowledge . Archived from the original on 10 January 2016 . Retrieved 11 June 2022 . ^ Strait DS (September 2010). "The Evolutionary History of the Australopiths" . Evolution: Education and Outreach . 3 (3): 341–352. doi : 10.1007/s12052-010-0249-6 . ISSN 1936-6434 . S2CID 31979188 . ^ Dunsworth HM (September 2010). "Origin of the Genus Homo" . Evolution: Education and Outreach . 3 (3): 353–366. doi : 10.1007/s12052-010-0247-8 . ISSN 1936-6434 . S2CID 43116946 . ^ Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1698): 20150248. doi : 10.1098/rstb.2015.0248 . PMC 4920303 . PMID 27298460 . S2CID 20267830 . ^ Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia" . Science . 347 (6228): 1352–1355. Bibcode : 2015Sci...347.1352V . doi : 10.1126/science.aaa1343 . PMID 25739410 . ^ Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature . 559 (7715): 608–612. Bibcode : 2018Natur.559..608Z . doi : 10.1038/s41586-018-0299-4 . PMID 29995848 . S2CID 49670311 . ^ Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF) . Nature . 546 (7657): 289–292. Bibcode : 2017Natur.546..289H . doi : 10.1038/nature22336 . PMID 28593953 . S2CID 256771372 . Archived (PDF) from the original on 8 January 2020 . Retrieved 30 July 2022 . ^ "Out of Africa Revisited". Science (This Week in Science ). 308 (5724): 921. 13 May 2005. doi : 10.1126/science.308.5724.921g . ISSN 0036-8075 . S2CID 220100436 . ^ Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature . 423 (6941): 692–693, 695. Bibcode : 2003Natur.423..692S . doi : 10.1038/423692a . PMID 12802315 . S2CID 26693109 . ^ Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?" . actionbioscience . Washington, DC: American Institute of Biological Sciences . Archived from the original on 17 June 2021 . Retrieved 23 November 2009 . ^ Marean, Curtis; et al. (2007). "Early human use of marine resources and pigment in South Africa during the Middle Pleistocene" (PDF) . Nature . 449 (7164): 905–908. Bibcode : 2007Natur.449..905M . doi : 10.1038/nature06204 . PMID 17943129 . S2CID 4387442 . Archived (PDF) from the original on 2023-05-25 . Retrieved 2023-01-07 . ^ Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB (2018). "Long-distance stone transport and pigment use in the earliest Middle Stone Age" . Science . 360 (6384): 90–94. Bibcode : 2018Sci...360...90B . doi : 10.1126/science.aao2646 . PMID 29545508 . ^ Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology . 26 (6): 827–833. Bibcode : 2016CBio...26..827P . doi : 10.1016/j.cub.2016.01.037 . hdl : 2440/114930 . PMID 26853362 . S2CID 140098861 . ^ Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture" . Genome Research . 25 (4): 459–466. doi : 10.1101/gr.186684.114 . PMC 4381518 . PMID 25770088 . ^ Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia" . Science . 331 (6016): 453–456. Bibcode : 2011Sci...331..453A . doi : 10.1126/science.1199113 . PMID 21273486 . S2CID 20296624 . Archived from the original on 27 April 2011 . Retrieved 1 May 2011 . ^ Rincon P (27 January 2011). "Humans 'left Africa much earlier' " . BBC News . Archived from the original on 9 August 2012. ^ Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature . 547 (7663): 306–310. Bibcode : 2017Natur.547..306C . doi : 10.1038/nature22968 . hdl : 2440/107043 . PMID 28726833 . S2CID 205257212 . ^ Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF) . University of Waikato . Archived (PDF) from the original on 22 May 2010 . Retrieved 29 April 2010 . ^ Appenzeller T (May 2012). "Human migrations: Eastern odyssey" . Nature . 485 (7396): 24–26. Bibcode : 2012Natur.485...24A . doi : 10.1038/485024a . PMID 22552074 . ^ Reich D , Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" . Nature . 468 (7327): 1053–1060. Bibcode : 2010Natur.468.1053R . doi : 10.1038/nature09710 . hdl : 10230/25596 . PMC 4306417 . PMID 21179161 . ^ Hammer MF (May 2013). "Human Hybrids" (PDF) . Scientific American . 308 (5): 66–71. Bibcode : 2013SciAm.308e..66H . doi : 10.1038/scientificamerican0513-66 . PMID 23627222 . Archived from the original (PDF) on 24 August 2018. ^ Yong E (July 2011). "Mosaic humans, the hybrid species" . New Scientist . 211 (2823): 34–38. Bibcode : 2011NewSc.211...34Y . doi : 10.1016/S0262-4079(11)61839-3 . ^ Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology . 43 (1): 1–11. doi : 10.1007/s11692-015-9348-1 . S2CID 14329491 . ^ Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans" . Genome Research . 20 (5): 547–553. doi : 10.1101/gr.076000.108 . PMC 2860157 . PMID 20439435 . ^ Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans" . Science . 334 (6052): 89–94. Bibcode : 2011Sci...334...89A . doi : 10.1126/science.1209202 . PMC 3677943 . PMID 21868630 . ^ Sandel, Aaron A. (30 July 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness" . American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . Archived from the original on 22 July 2023 . Retrieved 22 July 2023 . ^ Boyd R , Silk JB (2003). How Humans Evolved . New York: Norton . ISBN 978-0-393-97854-4 . ^ Little, Michael A.; Blumler, Mark A. (2015). "Hunter-Gatherers" . In Muehlenbein, Michael P. (ed.). Basics in Human Evolution . Boston: Academic Press. pp. 323–335. ISBN 978-0-12-802652-6 . Archived from the original on 3 July 2022 . Retrieved 30 July 2022 . ^ Scarre, Chris (2018). "The world transformed: from foragers and farmers to states and empires". In Scarre, Chris (ed.). The Human Past: World Prehistory and the Development of Human Societies (4th ed.). London: Thames & Hudson . pp. 174–197. ISBN 978-0-500-29335-5 . ^ Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe . Walnut Creek, CA: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5 . OCLC 855969933 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society . Elsevier. pp. 103–131. doi : 10.1016/B978-0-12-805247-1.00006-X . ISBN 978-0-12-805247-1 . ^ He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China" . The Holocene . 27 (12): 1885–1898. Bibcode : 2017Holoc..27.1885H . doi : 10.1177/0959683617708455 . S2CID 133660098 . Archived from the original on 20 November 2021 . Retrieved 30 July 2022 . ^ Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago" . Proceedings of the National Academy of Sciences of the United States of America . 106 (18): 7367–7372. Bibcode : 2009PNAS..106.7367L . doi : 10.1073/pnas.0900158106 . PMC 2678631 . PMID 19383791 . ^ Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea" . Science . 301 (5630): 189–193. doi : 10.1126/science.1085255 . PMID 12817084 . S2CID 10644185 . ^ Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication" . Science Advances . 5 (5): eaaw1947. Bibcode : 2019SciA....5.1947S . doi : 10.1126/sciadv.aaw1947 . PMC 6527260 . PMID 31114806 . ^ Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF) . Current Anthropology . 58 (5): 673–683. doi : 10.1086/693898 . S2CID 149402650 . Archived (PDF) from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science . 38 (2): 312–322. Bibcode : 2011JArSc..38..312M . doi : 10.1016/j.jas.2010.09.007 . ^ Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries . Cengage Learning. ISBN 978-1-285-66153-7 . Archived from the original on 27 February 2021 . Retrieved 11 July 2015 . ^ Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500 . Cenpage Learning. ISBN 978-1-285-98299-1 . Archived from the original on 10 August 2023 . Retrieved 11 July 2015 . ^ Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization . San Francisco: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3 . Archived from the original on 10 August 2023 . Retrieved 30 July 2022 . ^ Garfinkle, Steven J. (2013). "Ancient Near Eastern City-States". In Peter Fibiger Bang ; Walter Scheidel (eds.). The Oxford Handbook of the State in the Ancient Near East and Mediterranean . Oxford Academic. pp. 94–119. doi : 10.1093/oxfordhb/9780195188318.013.0004 . ISBN 978-0-19-518831-8 . ^ Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi : 10.1002/9781119193814.ch2 . ISBN 978-1-119-19329-6 . S2CID 216180781 . ^ Robinson A (October 2015). "Ancient civilization: Cracking the Indus script" . Nature . 526 (7574): 499–501. Bibcode : 2015Natur.526..499R . doi : 10.1038/526499a . PMID 26490603 . S2CID 4458743 . ^ Crawford H (2013). "Trade in the Sumerian world". The Sumerian World . Routledge. pp. 447–461. ISBN 978-1-136-21911-5 . ^ Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles" . Acta Archaeologica Academiae Scientiarum Hungaricae . 69 (2): 271–298. doi : 10.1556/072.2018.69.2.3 . ISSN 0001-5210 . S2CID 115685157 . Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Pryor FL (1985). "The Invention of the Plow" . Comparative Studies in Society and History . 27 (4): 727–743. doi : 10.1017/S0010417500011749 . ISSN 0010-4175 . JSTOR 178600 . S2CID 144840498 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Carter R (2012). "19. Watercraft ". In Potts DT (ed.). A companion to the archaeology of the ancient Near East . Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0 . Archived from the original on 28 April 2015 . Retrieved 8 February 2014 . ^ Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction . CUP Archive. p. 1. ISBN 978-0-521-40340-5 . ^ Robson E (2008). Mathematics in ancient Iraq: A social history . Princeton University Press. pp. xxi. ^ Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza" . Technology and Culture . 44 (2): 340–354. doi : 10.1353/tech.2003.0063 . ISSN 0040-165X . JSTOR 25148110 . S2CID 109998651 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Voosen P (August 2018). "New geological age comes under fire". Science . 361 (6402): 537–538. Bibcode : 2018Sci...361..537V . doi : 10.1126/science.361.6402.537 . PMID 30093579 . S2CID 51954326 . ^ Saggs HW (2000). Babylonians . Univ of California Press. p. 7. ISBN 978-0-520-20222-1 . ^ Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory . 12 (4): 335–364. doi : 10.1007/s10816-005-8460-4 . ISSN 1573-7764 . S2CID 53393440 . ^ Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans" . Nature . 548 (7666): 214–218. Bibcode : 2017Natur.548..214L . doi : 10.1038/nature23310 . PMC 5565772 . PMID 28783727 . ^ Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC . Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8 . ^ Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change . 6 (4): 369–382. Bibcode : 2015WIRCC...6..369K . doi : 10.1002/wcc.345 . S2CID 128460316 . ^ Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science . 39 (6): 1862–1870. Bibcode : 2012JArSc..39.1862D . doi : 10.1016/j.jas.2012.01.029 . ^ Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory . Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi : 10.1007/978-1-4419-6633-9_11 . ISBN 978-1-4419-6633-9 . ^ Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography . United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1 . ^ Beard M (2 October 2015). "Why ancient Rome matters to the modern world" . The Guardian . Archived from the original on 14 April 2021 . Retrieved 17 April 2021 . ^ Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece" . Stanford University . Archived from the original on 18 April 2021 . Retrieved 17 April 2021 . ^ Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature . 582 (7813): 530–533. Bibcode : 2020Natur.582..530I . doi : 10.1038/s41586-020-2343-4 . PMID 32494009 . S2CID 219281856 . ^ Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar" . Latin American Antiquity . 28 (1): 88–104. doi : 10.1017/laq.2016.4 . ISSN 1045-6635 . S2CID 164417025 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida" . Proceedings of the Seminar for Arabian Studies . 46 : 25–40. ISSN 0308-8421 . JSTOR 45163415 . Archived from the original on 28 April 2022 . Retrieved 30 July 2022 . ^ Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration . 21 (1): 25–86. doi : 10.1080/01900699808525297 . ISSN 0190-0692 . ^ Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age" . Journal of the American Oriental Society . 96 (1): 15–26. doi : 10.2307/599886 . ISSN 0003-0279 . JSTOR 599886 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty" . Architectural History . 63 : 1–36. doi : 10.1017/arh.2020.1 . ISSN 0066-622X . S2CID 229716130 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question" . Climate . 6 (4): 90. Bibcode : 2018Clim....6...90M . doi : 10.3390/cli6040090 . ^ Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World . New York: Oxford University Press. p. 72. ISBN 978-0-19-532819-6 . Retrieved 30 July 2022 . ^ Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies . International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi : 10.1007/978-3-319-24774-8_2 . ISBN 978-3-319-24774-8 . ^ Vidal-Nanquet P (1987). The Harper Atlas of World History . Harper & Row Publishers. p. 76. ^ Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land . Simon and Schuster. ISBN 978-1-84983-770-5 . ^ Adam King (2002). "Mississippian Period: Overview" . New Georgia Encyclopedia . Archived from the original on 19 August 2009 . Retrieved 15 November 2009 . ^ Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism . Cambridge University Press. p. 2. ISBN 0-521-31896-3 . ^ May T (2013). The Mongol Conquests in World History . Reaktion Books. p. 7. ISBN 978-1-86189-971-2 . ^ Canós-Donnay S (25 February 2019). "The Empire of Mali" . Oxford Research Encyclopedia of African History . Oxford University Press. doi : 10.1093/acrefore/9780190277734.013.266 . ISBN 978-0-19-027773-4 . Archived from the original on 20 October 2021 . Retrieved 7 May 2021 . ^ Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity" . Asian Perspectives . 37 (2): 135–164. ^ Kafadar C (1 January 1994). "Ottomans and Europe" . In Brady T, Oberman T, Tracy JD (eds.). Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation . Brill. pp. 589–635. doi : 10.1163/9789004391659_019 . ISBN 978-90-04-39165-9 . Archived from the original on 2 May 2022 . Retrieved 17 April 2021 . ^ Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan" . Oxford Research Encyclopedia of Asian History . Oxford University Press. doi : 10.1093/acrefore/9780190277727.013.72 . ISBN 978-0-19-027772-7 . Archived from the original on 12 August 2021 . Retrieved 7 May 2021 . ^ Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing" . Pacific Affairs . 83 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526–1857)" . Al-Ta Lim Journal . 23 (2): 128–138. doi : 10.15548/jt.v23i2.228 . ISSN 2355-7893 . Archived from the original on 7 April 2022 . Retrieved 30 July 2022 . ^ Kirkpatrick R (2002). The European Renaissance, 1400–1600 . Routledge. p. 1. ISBN 978-1-317-88646-4 . OCLC 893909816 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Arnold D (2002). The Age of Discovery, 1400–1600 (Second ed.). Routledge. pp. xi. ISBN 978-1-136-47968-7 . OCLC 859536800 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics" . Theoretical Inquiries in Law . 11 (1). doi : 10.2202/1565-3404.1239 . ISSN 1565-3404 . S2CID 56216309 . Archived from the original on 26 August 2021 . Retrieved 30 July 2022 . ^ Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews . 20 (1–3): 277–299. Bibcode : 2001QSRv...20..277J . doi : 10.1016/S0277-3791(00)00116-5 . ^ Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature" . The Journal of African History . 30 (3): 365–394. doi : 10.1017/S0021853700024439 . ISSN 0021-8537 . JSTOR 182914 . S2CID 161321949 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide . London: Palgrave Macmillan UK. pp. 273–295. doi : 10.1057/9780230297784_11 . ISBN 978-0-230-29778-4 . ^ Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour . 38 (3–4): 157–158. doi : 10.1016/j.endeavour.2014.10.001 . PMID 25457642 . ^ "Greatest Engineering Achievements of the 20th Century" . National Academy of Engineering . Archived from the original on 6 April 2015 . Retrieved 7 April 2015 . ^ Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776 . New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0 . OCLC 299054528 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815" . Journal of Global History . 1 (1): 123–149. doi : 10.1017/S1740022806000076 . ISSN 1740-0228 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Zimmerman AF (November 1931). "Spain and Its Colonies, 1808–1820" . The Hispanic American Historical Review . 11 (4): 439–463. doi : 10.2307/2506251 . JSTOR 2506251 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ David S (2011). "British History in depth: Slavery and the 'Scramble for Africa' " . BBC . Archived from the original on 24 March 2022 . Retrieved 5 May 2021 . ^ Raudzens G (2004). "The Australian Frontier Wars, 1788–1838 (review)" . The Journal of Military History . 68 (3): 957–959. doi : 10.1353/jmh.2004.0138 . ISSN 1543-7795 . S2CID 162259092 . ^ Clark CM (2012). "Polarization of Europe, 1887–1907". The sleepwalkers : how Europe went to war in 1914 . London: Allen Lane. ISBN 978-0-7139-9942-6 . OCLC 794136314 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Robert Dahl (1989). Democracy and Its Critics . Yale UP. pp. 239–240 . ISBN 0-300-15355-4 . ^ McDougall WA (May 1985). "Sputnik, the space race, and the Cold War" . Bulletin of the Atomic Scientists . 41 (5): 20–25. Bibcode : 1985BuAtS..41e..20M . doi : 10.1080/00963402.1985.11455962 . ISSN 0096-3402 . ^ Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?" . Journal of Peace Research . 30 (2): 163–179. doi : 10.1177/0022343393030002004 . ISSN 0022-3433 . S2CID 5482851 . Archived from the original on 21 February 2022 . Retrieved 30 July 2022 . ^ Sachs JD (April 2017). "Globalization – In the Name of Which Freedom?" . Humanistic Management Journal . 1 (2): 237–252. doi : 10.1007/s41463-017-0019-5 . ISSN 2366-603X . S2CID 133030709 . ^ "World" . The World Factbook . CIA . 17 May 2016. Archived from the original on 26 January 2021 . Retrieved 2 October 2016 . ^ "World Population Prospects: The 2017 Revision" (PDF) . United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17. Archived (PDF) from the original on 26 June 2019 . Retrieved 30 July 2022 . ^ "The World's Cities in 2018" (PDF) . United Nations . Archived (PDF) from the original on 1 November 2018. ^ Rector RK (2016). The Early River Valley Civilizations (First ed.). New York: Rosen Publishing. p. 10. ISBN 978-1-4994-6329-3 . OCLC 953735302 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ "How People Modify the Environment" (PDF) . Westerville City School District . Archived (PDF) from the original on 25 February 2021 . Retrieved 13 March 2019 . ^ "Natural disasters and the urban poor" (PDF) . World Bank . October 2003. Archived (PDF) from the original on 9 August 2017. ^ Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities . [London]: Routledge. pp. x. ISBN 978-1-135-01559-6 . OCLC 889953315 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Piantadosi CA (2003). The biology of human survival : life and death in extreme environments . Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5 . OCLC 70215878 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Toups, M.A.; Kitchen, A.; Light, J.E.; Reed, D.L. (2011). "Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa" . Molecular Biology and Evolution . 28 (1): 29–32. doi : 10.1093/molbev/msq234 . PMC 3002236 . PMID 20823373 . ^ O'Neil D. "Human Biological Adaptability; Overview" . Palomar College. Archived from the original on 6 March 2013 . Retrieved 6 January 2013 . ^ "Population distribution and density" . BBC. Archived from the original on 23 June 2017 . Retrieved 26 June 2017 . ^ Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management . 30 (4): 492–507. doi : 10.1007/s00267-002-2737-0 . hdl : 10072/6758 . PMID 12481916 . S2CID 25834286 . ^ Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica" . Vanderbilt Journal of Transnational Law . 23 : 819. Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ "Mission to Mars: Mars Science Laboratory Curiosity Rover" . Jet Propulsion Laboratory. Archived from the original on 18 August 2015 . Retrieved 26 August 2015 . ^ "Touchdown! Rosetta's Philae probe lands on comet" . European Space Agency. 12 November 2014. Archived from the original on 22 August 2015 . Retrieved 26 August 2015 . ^ "NEAR-Shoemaker" . NASA . Archived from the original on 26 August 2015 . Retrieved 26 August 2015 . ^ Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station" . JSC Features . Johnson Space Center . Archived from the original on 16 February 2012 . Retrieved 13 February 2012 . ^ Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth" . Proceedings of the National Academy of Sciences of the United States of America . 115 (25): 6506–6511. Bibcode : 2018PNAS..115.6506B . doi : 10.1073/pnas.1711842115 . PMC 6016768 . PMID 29784790 . ^ Tellier LN (2009). Urban world history: an economic and geographical perspective . Presses de l'Université du Québec. p. 26. ISBN 978-2-7605-1588-8 . Retrieved 30 July 2022 . ^ Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, CA: Dickenson Pub. Co. ISBN 978-0-8221-0166-6 . ^ Harl KW (1998). "Population estimates of the Roman Empire" . Tulane.edu. Archived from the original on 7 May 2016 . Retrieved 8 December 2012 . ^ Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis" . International Journal of Hygiene and Environmental Health . 207 (2): 165–178. doi : 10.1078/1438-4639-00259 . PMC 7128933 . PMID 15031959 . ^ "World's population reaches six billion" . BBC News . 5 August 1999. Archived from the original on 15 April 2008 . Retrieved 5 February 2008 . ^ United Nations. "World population to reach 8 billion on 15 November 2022" . United Nations . Archived from the original on 20 January 2023 . Retrieved 27 October 2022 . ^ "Eight billion people, SARS-CoV-2 ancestor and illegal fishing" . Nature . 611 (641): 641. 23 November 2022. Bibcode : 2022Natur.611..641. . doi : 10.1038/d41586-022-03792-4 . S2CID 253764233 . Archived from the original on 26 January 2023 . Retrieved 26 January 2023 . ^ "World Population to Hit Milestone With Birth of 7 Billionth Person" . PBS NewsHour . 27 October 2011. Archived from the original on 24 September 2017 . Retrieved 11 February 2018 . ^ "68% of the world population projected to live in urban areas by 2050, says UN" . United Nations Department of Economic and Social Affairs (DESA) . 16 May 2018. Archived from the original on 10 March 2021 . Retrieved 18 April 2021 . ^ Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF) . U.S. Department of Justice , Bureau of Justice Statistics. Archived (PDF) from the original on 24 February 2013 . Retrieved 1 October 2006 . ^ Roopnarine PD (March 2014). "Humans are apex predators" . Proceedings of the National Academy of Sciences of the United States of America . 111 (9): E796. Bibcode : 2014PNAS..111E.796R . doi : 10.1073/pnas.1323645111 . PMC 3948303 . PMID 24497513 . ^ Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature" . Science . AAAS . Archived from the original on 26 October 2021 . Retrieved 9 May 2021 . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use – principally agriculture – that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.) ^ Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions" . Proceedings of the National Academy of Sciences of the United States of America . 103 (29): 10941–10946. Bibcode : 2006PNAS..10310941P . doi : 10.1073/pnas.0604181103 . PMC 1544153 . PMID 16829570 . ^ Collins D (1976). The Human Revolution: From Ape to Artist . Phaidon. p. 208 . ISBN 978-0-7148-1676-0 . ^ Weisberger, Mindy (March 23, 2024). "Why don't humans have tails? Scientists find answers in an unlikely place" . CNN . Archived from the original on March 24, 2024 . Retrieved March 24, 2024 . ^ Marks JM (2001). Human Biodiversity: Genes, Race, and History . Transaction Publishers. p. 16. ISBN 978-0-202-36656-2 . ^ Gea, J (2008). "The Evolution of the Human Species: A Long Journey for the Respiratory System". Archivos de Bronconeumología ((English Edition)) . 44 (5): 263–270. doi : 10.1016/S1579-2129(08)60042-7 . ^ O'Neil D. "Humans" . Primates . Palomar College. Archived from the original on 11 January 2013 . Retrieved 6 January 2013 . ^ "How to be Human: The reason we are so scarily hairy" . New Scientist . 2017. Archived from the original on 25 February 2021 . Retrieved 29 April 2020 . ^ Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . ^ Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White" . Evolution: Library . PBS. Archived from the original on 16 February 2013 . Retrieved 6 January 2013 . ^ Roser M, Appel C, Ritchie H (8 October 2013). "Human Height" . Our World in Data . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ "Senior Citizens Do Shrink – Just One of the Body Changes of Aging" . News . Senior Journal. Archived from the original on 19 February 2013 . Retrieved 6 January 2013 . ^ Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology . 136 (1): 71–84. doi : 10.1016/S1095-6433(02)00294-5 . PMID 14527631 . ^ "Human weight" . Articleworld.org. Archived from the original on 8 December 2011 . Retrieved 10 December 2011 . ^ Schlessingerman A (2003). "Mass Of An Adult" . The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018 . Retrieved 31 December 2017 . ^ Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology) . Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1 . Retrieved 5 April 2009 . ^ Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care" . British Journal of Anaesthesia . 85 (1): 91–108. doi : 10.1093/bja/85.1.91 . PMID 10927998 . ^ Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology . 93 (1): 1–16. doi : 10.1086/696721 . ISSN 0033-5770 . S2CID 90757192 . ^ Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance" . The New York Times . Archived from the original on 5 November 2015. ^ John B. "What is the role of sweating glands in balancing body temperature when running a marathon?" . Livestrong.com. Archived from the original on 31 January 2013 . Retrieved 6 January 2013 . ^ Shave, R. E.; Lieberman, D. E.; Drane, A. L.; et al. (2019). "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart" . PNAS . 116 (40): 19905–19910. Bibcode : 2019PNAS..11619905S . doi : 10.1073/pnas.1906902116 . PMC 6778238 . PMID 31527253 . ^ Ríos, L; Sleeper, M. M.; Danforth, M. D.; et al. (2023). "The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution" . Scientific Reports . 13 (6841): 6841. Bibcode : 2023NatSR..13.6841R . doi : 10.1038/s41598-023-33675-1 . hdl : 10261/309357 . PMC 10133235 . PMID 37100851 . ^ Therman E (1980). Human Chromosomes: Structure, Behavior, Effects . Springer US . pp. 112–124. doi : 10.1007/978-1-4684-0107-3 . ISBN 978-1-4684-0109-7 . S2CID 36686283 . ^ Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex" . Journal of Medical Genetics . 3 (2): 117–123. doi : 10.1136/jmg.3.2.117 . PMC 1012913 . PMID 6007033 . ^ Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics . 61 (3): 216–228. doi : 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S . PMID 8741866 . ^ Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics . 53 (1): 27–34. doi : 10.1038/s41588-020-00755-1 . PMID 33414551 . S2CID 230986741 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . Between any two humans, the amount of genetic variation – biochemical individuality – is about 0.1%. ^ Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human" . PLOS Biology . 5 (10): e254. doi : 10.1371/journal.pbio.0050254 . PMC 1964779 . PMID 17803354 . ^ Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research" . American Journal of Human Genetics . 77 (4): 519–532. doi : 10.1086/491747 . PMC 1275602 . PMID 16175499 . ^ "Chimps show much greater genetic diversity than humans" . Media . University of Oxford. Archived from the original on 18 December 2013 . Retrieved 13 December 2013 . ^ Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography" . Proceedings of the National Academy of Sciences of the United States of America . 95 (4): 1961–1967. Bibcode : 1998PNAS...95.1961H . doi : 10.1073/pnas.95.4.1961 . PMC 19224 . PMID 9465125 . ^ Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans" . Proceedings of the National Academy of Sciences of the United States of America . 94 (7): 3100–3103. Bibcode : 1997PNAS...94.3100J . doi : 10.1073/pnas.94.7.3100 . PMC 20328 . PMID 9096352 . ^ Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story" . The New York Times . Archived from the original on 14 January 2012 . Retrieved 13 February 2012 . ^ Pennisi E (February 2001). "The human genome". Science . 291 (5507): 1177–1180. doi : 10.1126/science.291.5507.1177 . PMID 11233420 . S2CID 38355565 . ^ Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature . 590 (7845): 220–221. Bibcode : 2021Natur.590..220R . doi : 10.1038/d41586-021-00237-2 . PMID 33568827 . S2CID 231882262 . ^ Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations" . Nature . 467 (7311): 52–58. Bibcode : 2010Natur.467...52T . doi : 10.1038/nature09298 . PMC 3173859 . PMID 20811451 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private , common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture. ^ Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes" . Genome Biology . 11 (5): 206. doi : 10.1186/gb-2010-11-5-206 . PMC 2898077 . PMID 20441615 . ^ Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature . 325 (6099): 31–36. Bibcode : 1987Natur.325...31C . doi : 10.1038/325031a0 . PMID 3025745 . S2CID 4285418 . ^ Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock" . American Journal of Human Genetics . 84 (6): 740–759. doi : 10.1016/j.ajhg.2009.05.001 . PMC 2694979 . PMID 19500773 . ^ "University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history" . 20 August 2017. Archived from the original on 20 August 2017. ^ Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females" . Science . 341 (6145): 562–565. Bibcode : 2013Sci...341..562P . doi : 10.1126/science.1237619 . PMC 4032117 . PMID 23908239 . ^ Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set . John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1 . ^ Jukic AM, Baird DD, Weinberg CR , McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation" . Human Reproduction . 28 (10): 2848–2855. doi : 10.1093/humrep/det297 . PMC 3777570 . PMID 23922246 . ^ Klossner NJ (2005). Introductory Maternity Nursing . Lippincott Williams & Wilkins. p. 103. ISBN 978-0-7817-6237-3 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . The fetal stage is from the beginning of the 9th week after fertilization and continues until birth ^ World Health Organization (November 2014). "Preterm birth Fact sheet N°363" . who.int . Archived from the original on 7 March 2015 . Retrieved 6 March 2015 . ^ Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application" . American Journal of Obstetrics and Gynecology . 218 (2S): S619–S629. doi : 10.1016/j.ajog.2017.12.010 . PMID 29422204 . S2CID 46810955 . ^ "What is the average baby length? Growth chart by month" . www.medicalnewstoday.com . 18 March 2019. Archived from the original on 27 January 2021 . Retrieved 18 April 2021 . ^ Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal . 5 (2): 113–122. PMID 15024783 . ^ Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology . 35 (S15): 89–124. doi : 10.1002/ajpa.1330350605 . ISSN 1096-8644 . ^ Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma" . American Journal of Obstetrics and Gynecology . 222 (1): 3–16. doi : 10.1016/j.ajog.2019.06.043 . PMC 9069416 . PMID 31251927 . S2CID 195761874 . ^ Barras C (22 December 2016). "The real reasons why childbirth is so painful and dangerous". BBC. ^ Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?" . Newsweek . Archived from the original on 28 June 2007. A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa , compared to 1 in 2,800 in developed countries . ^ Rush D (July 2000). "Nutrition and maternal mortality in the developing world" . The American Journal of Clinical Nutrition . 72 (1 Suppl): 212S–240S. doi : 10.1093/ajcn/72.1.212S . PMID 10871588 . ^ Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour . Oxford University Press. p. 7. ISBN 978-0-19-958696-7 . Retrieved 30 July 2022 . ^ Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning . p. 296. ISBN 978-0-495-60037-4 . Archived from the original on 3 October 2023 . Retrieved 30 July 2022 . ^ Schuiling KD, Likis FE (2016). Women's Gynecologic Health . Jones & Bartlett Learning . p. 22. ISBN 978-1-284-12501-6 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13. ^ Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy . SAGE Publications . pp. 18–19. ISBN 978-1-4833-6475-9 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average). ^ Mintz S (1993). "Life stages". Encyclopedia of American Social History . 3 : 7–33. ^ Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?" . Indian Journal of Endocrinology and Metabolism . 18 (Suppl 1): S53-62. doi : 10.4103/2230-8210.145075 . PMC 4266869 . PMID 25538878 . ^ Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?" . Biology of Reproduction . 79 (3): 398–406. doi : 10.1095/biolreprod.108.068536 . PMC 2553520 . PMID 18495681 . ^ Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality . New York: Basic Books. pp. 167–170. ISBN 978-0-465-03127-6 . ^ Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology . 10 (2): 43–57. doi : 10.1002/evan.1013 . S2CID 1665503 . ^ Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth" . USC Trojan Family Magazine . Archived from the original on 13 December 2010 . Retrieved 7 December 2010 . ^ Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex" . Society of Actuaries. Archived from the original on 1 July 2013. ^ "Life expectancy at birth, female (years)" . World Bank . 2018. Archived from the original on 24 January 2021 . Retrieved 13 October 2020 . ^ "Life expectancy at birth, male (years)" . World Bank . 2018. Archived from the original on 24 February 2021 . Retrieved 13 October 2020 . ^ Conceição P, et al. (2019). Human Development Report (PDF) . United Nations Development Programme. ISBN 978-92-1-126439-5 . Archived (PDF) from the original on 20 March 2021 . Retrieved 30 July 2022 . ^ "Human Development Report 2019" (PDF) . United Nations Development Programme . Archived from the original (PDF) on 22 April 2022 . Retrieved 30 July 2022 . ^ "The World Factbook" . U.S. Central Intelligence Agency. Archived from the original on 12 September 2009 . Retrieved 2 April 2005 . ^ "Chapter 1: Setting the Scene" (PDF) . UNFPA. 2012. Archived from the original (PDF) on 12 June 2013 . Retrieved 11 January 2013 . ^ Haenel H (1989). "Phylogenesis and nutrition". Die Nahrung . 33 (9): 867–887. PMID 2697806 . ^ Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable . pp. 264–265. Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods. ^ American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association . 103 (6): 748–765. doi : 10.1053/jada.2003.50142 . PMID 12778049 . ^ Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet" . American Journal of Physical Anthropology . 162 (S63): 84–109. doi : 10.1002/ajpa.23148 . PMID 28105723 . ^ Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century" . The American Journal of Clinical Nutrition . 81 (2): 341–354. doi : 10.1093/ajcn.81.2.341 . PMID 15699220 . ^ Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context" . The Proceedings of the Nutrition Society . 61 (4): 517–526. doi : 10.1079/PNS2002180 . PMID 12691181 . ^ John Carey (2023). "Unearthing the origins of agriculture" . Proceedings of the National Academy of Sciences . 120 (15): e2304407120. Bibcode : 2023PNAS..12004407C . doi : 10.1073/pnas.2304407120 . PMC 10104519 . PMID 37018195 . ^ Ayelet Shavit; Gonen Sharon (2023). "Can models of evolutionary transition clarify the debates over the Neolithic Revolution?" . Philosophical Transactions of the Royal Society B . 378 (1872). doi : 10.1098/rstb.2021.0413 . PMC 9869441 . PMID 36688395 . } ^ Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences" . The American Journal of Clinical Nutrition . 90 (3): 707S–711S. doi : 10.3945/ajcn.2009.27462B . PMID 19656837 . ^ Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology . 69 (5): 605–628. PMID 9299882 . ^ Gibbons A. "The Evolution of Diet" . National Geographic . Archived from the original on 18 August 2014 . Retrieved 18 April 2021 . ^ Ritchie H, Roser M (20 August 2017). "Diet Compositions" . Our World in Data . Archived from the original on 25 August 2021 . Retrieved 30 July 2022 . ^ Lieberson AD (2004). "How Long Can a Person Survive without Food?" . Scientific American . Archived from the original on 14 February 2019 . Retrieved 18 April 2021 . ^ Spector D (9 March 2018). "Here's how many days a person can survive without water" . Business Insider Australia . Archived from the original on 26 June 2014 . Retrieved 18 April 2021 . ^ Holmes J. "Losing 25,000 to Hunger Every Day" . United Nations . Archived from the original on 27 May 2020 . Retrieved 18 April 2021 . ^ Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic" . NPR . Archived from the original on 28 June 2021 . Retrieved 18 April 2021 . ^ Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet . 349 (9063): 1436–1442. doi : 10.1016/S0140-6736(96)07495-8 . PMID 9164317 . S2CID 2569153 . ^ Haslam DW, James WP (October 2005). "Obesity". Lancet . 366 (9492): 1197–1209. doi : 10.1016/S0140-6736(05)67483-1 . PMID 16198769 . S2CID 208791491 . ^ Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine . 30 (3): 415–444, vii. doi : 10.1016/j.ccm.2009.05.001 . PMID 19700042 . ^ de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology . 2 (1): 45–55. doi : 10.1016/j.ehb.2003.11.001 . PMID 15463992 . ^ O'Neil D. "Adapting to Climate Extremes" . Human Biological Adaptability . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status" . PLOS Genetics . 13 (9): e1006977. doi : 10.1371/journal.pgen.1006977 . PMC 5600404 . PMID 28873402 . ^ Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics . 35 (4): 311–313. doi : 10.1038/ng1263 . PMID 14634648 . S2CID 20415396 . ^ Hedrick PW (October 2011). "Population genetics of malaria resistance in humans" . Heredity . 107 (4): 283–304. doi : 10.1038/hdy.2011.16 . PMC 3182497 . PMID 21427751 . ^ Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria" . British Journal of Haematology . 141 (3): 276–286. doi : 10.1111/j.1365-2141.2008.07085.x . PMID 18410566 . S2CID 28191911 . ^ Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea" . Frontiers in Ecology and Evolution . 5 . doi : 10.3389/fevo.2017.00025 . hdl : 11858/00-001M-0000-002C-DD87-4 . ISSN 2296-701X . S2CID 34882477 . ^ Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads" . Cell . 173 (3): 569–580.e15. doi : 10.1016/j.cell.2018.03.054 . PMID 29677510 . ^ Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology . 45 (1): 105–08. doi : 10.1086/381006 . S2CID 224795768 . ^ Roberts D (2011). Fatal Invention . London & New York: The New Press. ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation" . Proceedings of the National Academy of Sciences of the United States of America . 107 (Supplement_2): 8962–8968. Bibcode : 2010PNAS..107.8962J . doi : 10.1073/pnas.0914628107 . PMC 3024016 . PMID 20445093 . ^ Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF) . Journal of Human Evolution . 39 (1): 57–106. doi : 10.1006/jhev.2000.0403 . PMID 10896812 . Archived from the original (PDF) on 14 January 2012. ^ Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R" . American Journal of Human Genetics . 66 (4): 1351–1361. doi : 10.1086/302863 . PMC 1288200 . PMID 10733465 . ^ Robin A (1991). Biological Perspectives on Human Pigmentation . Cambridge: Cambridge University Press. ^ "The Science Behind the Human Genome Project" . Human Genome Project . US Department of Energy. Archived from the original on 2 January 2013 . Retrieved 6 January 2013 . Almost all (99.9%) nucleotide bases are exactly the same in all people. ^ O'Neil D. "Ethnicity and Race: Overview" . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation" . Nature Genetics . 36 (11 Suppl): S17-20. doi : 10.1038/ng1455 . PMID 15507998 . ^ O'Neil D. "Models of Classification" . Modern Human Variation . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Palmié S (May 2007). "Genomics, divination, 'racecraft' ". American Ethnologist . 34 (2): 205–222. doi : 10.1525/ae.2007.34.2.205 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations. ^ Goodman A. "Interview with Alan Goodman" . Race Power of and Illusion . PBS. Archived from the original on 29 October 2012 . Retrieved 6 January 2013 . ^ Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF) . New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012 . Retrieved 5 September 2013 . ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo ^ O'Neil D. "Overview" . Modern Human Variation . Palomar College. Archived from the original on 5 November 2012 . Retrieved 6 January 2013 . ^ Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" . American Journal of Human Genetics . 66 (3): 979–988. doi : 10.1086/302825 . PMC 1288178 . PMID 10712212 . ^ "New Research Proves Single Origin Of Humans In Africa" . Science Daily . 19 July 2007. Archived from the original on 4 November 2011 . Retrieved 5 September 2011 . ^ Manica A, Amos W, Balloux F , Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation" . Nature . 448 (7151): 346–348. Bibcode : 2007Natur.448..346M . doi : 10.1038/nature05951 . PMC 1978547 . PMID 17637668 . ^ Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals" . Cell . 180 (4): 677–687.e16. doi : 10.1016/j.cell.2020.01.012 . PMID 32004458 . S2CID 210955842 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations. ^ Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations" . Science Advances . 6 (7): eaax5097. Bibcode : 2020SciA....6.5097D . doi : 10.1126/sciadv.aax5097 . PMC 7015685 . PMID 32095519 . Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. ^ Pierce BA (2012). Genetics: A Conceptual Approach . Macmillan. p. 75. ISBN 978-1-4292-3252-4 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology . Cambridge University Press. p. 74. ISBN 978-0-521-87948-4 . Retrieved 30 July 2022 . ^ Fusco G, Minelli A (10 October 2019). The Biology of Reproduction . Cambridge University Press. p. 304. ISBN 978-1-108-49985-9 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution . 47 (4): 253–266. doi : 10.1016/j.jhevol.2004.07.004 . PMID 15454336 . ^ Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960–2002" (PDF) . Advance Data (347): 1–17. PMID 15544194 . Archived from the original (PDF) on 23 February 2011. ^ Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology . 66 (3): 254–262. doi : 10.1007/BF00235103 . hdl : 11375/22586 . PMID 8477683 . S2CID 206772211 . ^ Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity . Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi : 10.1007/978-3-319-70178-3_2 . ISBN 978-3-319-70177-6 . PMID 29224088 . ^ Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know" . International Journal of Women's Dermatology . 4 (3): 122–130. doi : 10.1016/j.ijwd.2018.03.002 . PMC 6116811 . PMID 30175213 . ^ Easter C. "Sex Linked" . National Human Genome Research Institute . Archived from the original on 14 April 2022 . Retrieved 18 April 2021 . ^ Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior . 27 (4): 283–296. doi : 10.1016/j.evolhumbehav.2005.11.003 . S2CID 32562654 . ^ "Gender, women, and health" . Reports from WHO 2002–2005 . Archived from the original on 25 June 2013. ^ Sax, Leonard (1 August 2002). "How common is lntersex? A response to Anne Fausto-Sterling" . The Journal of Sex Research . 39 (3): 174–178. doi : 10.1080/00224490209552139 . ISSN 0022-4499 . PMID 12476264 . S2CID 33795209 . ^ "3-D Brain Anatomy" . The Secret Life of the Brain . Public Broadcasting Service. Archived from the original on 5 September 2017 . Retrieved 3 April 2005 . ^ Stern P (22 June 2018). "The human prefrontal cortex is special" . Science . 360 (6395): 1311–1312. Bibcode : 2018Sci...360S1311S . doi : 10.1126/science.360.6395.1311-g . ISSN 0036-8075 . S2CID 149581944 . ^ Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?" . Journal of Intelligence . 2 (3): 119–121. doi : 10.3390/jintelligence2030119 . ISSN 2079-3200 . ^ "Humans not smarter than animals, just different, experts say" . phys.org . Archived from the original on 30 January 2021 . Retrieved 24 October 2020 . ^ Robson D. "We've got human intelligence all wrong" . www.bbc.com . Archived from the original on 31 January 2021 . Retrieved 24 October 2020 . ^ Owen J (26 February 2015). "Many Animals – Including Your Dog – May Have Horrible Short-Term Memories" . National Geographic News . Archived from the original on 19 April 2021 . Retrieved 6 September 2020 . ^ Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research" . American Journal of Physical Anthropology . 116 (S33): 3–24. doi : 10.1002/ajpa.20001 . PMC 2238342 . PMID 11786989 . ^ Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?" . ABC News (American) . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self" . New Scientist . Archived from the original on 18 February 2021 . Retrieved 22 April 2020 . ^ Beck J (2019). "Can We Really Know What Animals Are Thinking?" . Snopes . Archived from the original on 31 October 2021 . Retrieved 22 April 2020 . ^ Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies" . Sleep Medicine Reviews . 14 (4): 239–247. doi : 10.1016/j.smrv.2009.08.001 . PMC 2888649 . PMID 19896872 . ^ Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep" " . Science.howstuffworks.com. Archived from the original on 15 May 2012 . Retrieved 11 August 2012 . ^ Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience . 10 (11): 803–813. doi : 10.1038/nrn2716 . PMID 19794431 . S2CID 205505278 . ^ Empson J (2002). Sleep and dreaming (3rd ed.). New York: Palgrave/St. Martin's Press. ^ Lite J (29 July 2010). "How Can You Control Your Dreams?" . Scientific America . Archived from the original on 2 February 2015. ^ Domhoff W (2002). The scientific study of dreams . APA Press. ^ "Consciousness" . Merriam-Webster . Archived from the original on 7 September 2019 . Retrieved 4 June 2012 . ^ van Gulick R (2004). "Consciousness" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019 . Retrieved 30 July 2022 . ^ Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness . Wiley. ISBN 978-0-470-75145-9 . ^ Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy . Oxford University Press. ISBN 978-0-19-926479-7 . ^ Block N (June 1995). "On a confusion about a function of consciousness" . Behavioral and Brain Sciences . 18 (2): 227–247. doi : 10.1017/S0140525X00038474 . S2CID 246244859 . ^ Jaynes J (2000) [1976]. The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF) . Houghton Mifflin. ISBN 0-618-05707-2 . Archived from the original (PDF) on 7 August 2019 . Retrieved 25 October 2020 . ^ Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition . 12 (4): 717–731. doi : 10.1016/s1053-8100(03)00081-3 . PMID 14656513 . S2CID 10241157 . ^ Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness" . Stanford Encyclopedia of Philosophy . Archived from the original on 13 April 2021 . Retrieved 31 August 2014 . ^ Antony MV (2001). "Is consciousness ambiguous?". Journal of Consciousness Studies . 8 : 19–44. ^ "Cognition" . Lexico . Oxford University Press and Dictionary.com . Archived from the original on 8 July 2016 . Retrieved 6 May 2020 . ^ Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality . The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi : 10.1007/978-3-030-03633-1_14 . ISBN 978-3-030-03633-1 . S2CID 189379814 . ^ "American Psychological Association (2013). Glossary of psychological terms" . Apa.org. Archived from the original on 8 July 2014 . Retrieved 13 August 2014 . ^ "Developmental Psychology Studies Human Development Across the Lifespan" . www.apa.org . Archived from the original on 9 July 2014 . Retrieved 28 August 2017 . ^ Burman E (2017). Deconstructing Developmental Psychology . New York: Routledge. ISBN 978-1-138-84695-1 . ^ Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology : 307–314. doi : 10.1016/B0-12-657410-3/00510-9 . ISBN 978-0-12-657410-4 . ^ McLeod S (20 March 2020). "Maslow's Hierarchy of Needs" . Simplypsychology.org . Simply Scholar Limited. Archived from the original on 8 November 2018 . Retrieved 4 April 2020 . Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up. ^ Heckhausen J, Heckhausen H (28 March 2018). "Motivation and Action: Introduction and Overview". Motivation and Action . Introduction and Overview: Springer, Cham. p. 1. doi : 10.1007/978-3-319-65094-4_1 . ISBN 978-3-319-65093-7 . ^ Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews . 26 (2–3): 83–86. doi : 10.1016/s0165-0173(97)00064-7 . PMID 9651488 . S2CID 8504450 . ^ Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions . New York: Oxford University Press. pp. 291–293. ISBN 978-0-19-508944-8 . Emotional processing, but not emotions, can occur unconsciously. ^ Cabanac M (2002). "What is emotion?". Behavioural Processes . 60 (2): 69–83. doi : 10.1016/S0376-6357(02)00078-5 . PMID 12426062 . S2CID 24365776 . Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure) ^ Scirst DL (2011). Psychology Second Edition . New York: Worth Publishers. p. 310 . ISBN 978-1-4292-3719-2 . ^ Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality . 67 (2): 331–371. doi : 10.1111/1467-6494.00058 . PMID 10202807 . ^ Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory" . Frontiers in Psychology . 8 : 1454. doi : 10.3389/fpsyg.2017.01454 . PMC 5573739 . PMID 28883804 . ^ Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology . Oxford University Press. Archived from the original on 29 January 2021 . Retrieved 30 July 2022 . ^ Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals" . Industrial Psychiatry Journal . 24 (1): 54–58. doi : 10.4103/0972-6748.160934 . PMC 4525433 . PMID 26257484 . ^ Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions" . The American Psychologist . 56 (3): 218–226. doi : 10.1037/0003-066X.56.3.218 . PMC 3122271 . PMID 11315248 . ^ Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica . 90 (3): 387–411. doi : 10.11612/resphil.2013.90.3.5 . ^ Haybron DM (13 April 2014). "Happiness and Its Discontents" . The Opinion Pages . The New York Times. Archived from the original on 12 October 2018 . Retrieved 30 July 2022 . I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life. ^ Graham MC (2014). Facts of Life: ten issues of contentment . Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5 . ^ "Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy" . ScienceDaily . American Psychological Association . 14 August 2017. Archived from the original on 11 November 2020 . Retrieved 25 October 2020 . ^ Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality . Jones & Bartlett Publishers . pp. 4–10. ISBN 978-1-284-08154-1 . Retrieved 21 June 2017 . Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings. ^ Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives . Taylor & Francis . pp. 32–42. ISBN 978-0-7890-2671-2 . ^ Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology . 3 (4): 85–89. doi : 10.1097/01.XHA.0000432482.01760.b0 . S2CID 147235090 . ^ "Sexual orientation, homosexuality and bisexuality" . American Psychological Association . Archived from the original on 8 August 2013 . Retrieved 10 August 2013 . ^ Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science" . Psychological Science in the Public Interest . 17 (2): 45–101. doi : 10.1177/1529100616637616 . PMID 27113562 . ^ LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation . Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6 . Retrieved 30 July 2022 . ^ Balthazart J (2012). The Biology of Homosexuality . Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0 . Retrieved 30 July 2022 . ^ Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York: Basic Books. ISBN 978-0-465-00802-5 . ^ Fromm E (2000). The art of loving . New York: Harper Perennial. ISBN 978-0-06-095828-2 . ^ "Love, Actually: The science behind lust, attraction, and companionship" . Science in the News . 14 February 2017. Archived from the original on 28 October 2020 . Retrieved 25 October 2020 . ^ "What are the top 200 most spoken languages?" . Ethnologue: Languages of the World . 2020. Archived from the original on 12 January 2013 . Retrieved 30 July 2022 . ^ World . The World Factbook (Report). Central Intelligence Agency . Archived from the original on 26 January 2021 . Retrieved 15 November 2021 . ^ "The Changing Global Religious Landscape" . Pew Research Center. 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 30 July 2022 . ^ Ord T (2020). The Precipice: Existential Risk and the Future of Humanity . New York: Hachette Books. ISBN 978-0-316-48489-3 . Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence... ^ Goldman JG (2012). "Pay attention… time for lessons at animal school" . bbc.com . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding" . Science Advances . 4 (11): eaar8334. Bibcode : 2018SciA....4.8334W . doi : 10.1126/sciadv.aar8334 . PMC 6248967 . PMID 30474053 . ^ Johnson-Frey SH (July 2003). "What's so special about human tool use?" . Neuron . 39 (2): 201–204. doi : 10.1016/S0896-6273(03)00424-0 . PMID 12873378 . S2CID 18437970 . ^ Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology . 19 (1): 27–33. doi : 10.1016/j.conb.2009.02.003 . PMID 19328675 . S2CID 18277620 . In short, the evidence to date that animals have an understanding of folk physics is at best mixed. ^ Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To" . National Geographic News . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education" . Procedia - Social and Behavioral Sciences . The Proceedings of 6th World Conference on educational Sciences. 191 : 2565–2567. doi : 10.1016/j.sbspro.2015.04.690 . ISSN 1877-0428 . ^ McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species" . The Guardian . Archived from the original on 5 February 2021 . Retrieved 22 April 2020 . ^ Nicholls H (29 June 2015). "Babblers speak to the origin of language" . The Guardian . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Dasgupta S (2015). "Can any animals talk and use language like humans?" . bbc.com . Archived from the original on 2 May 2020 . Retrieved 22 April 2020 . Most animals are not vocal learners. ^ Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?" . Royal Society. Archived from the original on 18 January 2021 . Retrieved 24 October 2020 . ^ Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?" . BMC Biology . 15 (1): 64. doi : 10.1186/s12915-017-0405-3 . PMC 5525259 . PMID 28738867 . ^ Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist . 208 (2789): ii–iii. Bibcode : 2010NewSc.208D...2F . doi : 10.1016/S0262-4079(10)62961-2 . ISSN 0262-4079 . ^ Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments . London: Palgrave Macmillan UK. pp. 229–255. doi : 10.1057/978-1-137-58746-6_7 . ISBN 978-1-137-58746-6 . ^ "Culture | United Nations For Indigenous Peoples" . www.un.org . 5 June 2015. Archived from the original on 26 November 2020 . Retrieved 24 October 2020 . ^ Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World . New York: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1 . ^ Mavrody S (2013). Visual Art Forms: Traditional to Digital . Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9 . Retrieved 30 July 2022 . ^ "Types of Literary Arts and Their Understanding – bookfestivalscotland.com" . Bookfestival Scotland . 2020. Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ "Bachelor of Performing Arts" (PDF) . University of Otago . Archived (PDF) from the original on 14 December 2021 . Retrieved 30 July 2022 . ^ Brown S (24 October 2018). "Toward a Unification of the Arts" . Frontiers in Psychology . 9 : 1938. doi : 10.3389/fpsyg.2018.01938 . ISSN 1664-1078 . PMC 6207603 . PMID 30405470 . ^ "Culinary arts – How cooking can be an art" . Northern Contemporary Art . 21 October 2019. Archived from the original on 11 May 2021 . Retrieved 5 May 2021 . ^ Smuts A (1 January 2005). "Are Video Games Art?" . Contemporary Aesthetics (Journal Archive) . 3 (1). Archived from the original on 29 May 2022 . Retrieved 30 July 2022 . ^ Cameron IA, Pimlott N (September 2015). "Art of medicine" . Canadian Family Physician . 61 (9): 739–740. PMC 4569099 . PMID 26371092 . ^ Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy . 25 (4): 458–470. doi : 10.1080/10286632.2017.1311328 . ISSN 1028-6632 . S2CID 151443044 . ^ Morriss-Kay GM (February 2010). "The evolution of human artistic creativity" . Journal of Anatomy . 216 (2): 158–176. doi : 10.1111/j.1469-7580.2009.01160.x . PMC 2815939 . PMID 19900185 . ^ Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature . 518 (7538): 228–231. Bibcode : 2015Natur.518..228J . doi : 10.1038/nature13962 . PMID 25470048 . S2CID 4461751 . ^ St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave" . The New York Times . Archived from the original on 14 April 2020 . Retrieved 20 September 2018 . ^ Radford T (16 April 2004). "World's oldest jewellery found in cave" . The Guardian . ISSN 0261-3077 . Archived from the original on 12 February 2021 . Retrieved 23 September 2020 . ^ Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches . Amsterdam: Valiz. pp. 241–263. ^ Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia . 92 (92): 147–177. doi : 10.4436/JASS.92008 (inactive 2024-03-20). PMID 25020016 . {{ cite journal }} : CS1 maint: DOI inactive as of March 2024 ( link ) ^ Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness" (PDF) . NeuroImage . 103 : 55–64. doi : 10.1016/j.neuroimage.2014.09.009 . PMID 25224999 . S2CID 4727529 . ^ Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences . 1337 (1): 140–146. Bibcode : 2015NYASA1337..140K . doi : 10.1111/nyas.12632 . PMID 25773628 . S2CID 206224849 . ^ Chow D (22 March 2010). "Why Do Humans Dance?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 21 September 2020 . ^ Krakauer J (26 September 2008). "Why do we like to dance – And move to the beat?" . Scientific American . Archived from the original on 28 February 2021 . Retrieved 21 September 2020 . ^ Prior KS (21 June 2013). "How Reading Makes Us More Human" . The Atlantic . Archived from the original on 29 January 2021 . Retrieved 23 September 2020 . ^ Puchner M. "How stories have shaped the world" . www.bbc.com . Archived from the original on 5 January 2021 . Retrieved 23 September 2020 . ^ Dalley, Stephanie , ed. (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5 . ^ Hernadi P (2001). "Literature and Evolution" . SubStance . 30 (1/2): 55–71. doi : 10.2307/3685504 . ISSN 0049-2426 . JSTOR 3685504 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run" . The Guardian (U.S. ed.). New York. Archived from the original on 18 June 2022 . Retrieved 30 July 2022 . ^ Clark JD; de Heinzelin J ; Schick KD ; Hart WK; White TD ; WoldeGabriel G; Walter RC; Suwa G ; Asfaw B ; Vrba E ; H.-Selassie Y (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science . 264 (5167): 1907–1910. Bibcode : 1994Sci...264.1907C . doi : 10.1126/science.8009220 . PMID 8009220 . ^ Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use" . livescience.com . Archived from the original on 4 October 2020 . Retrieved 9 October 2020 . ^ Orban GA, Caruana F (2014). "The neural basis of human tool use" . Frontiers in Psychology . 5 : 310. doi : 10.3389/fpsyg.2014.00310 . PMC 3988392 . PMID 24782809 . ^ Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa" . Proceedings of the National Academy of Sciences of the United States of America . 109 (20): E1215-20. doi : 10.1073/pnas.1117620109 . PMC 3356665 . PMID 22474385 . ^ Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1696): 20150164. doi : 10.1098/rstb.2015.0164 . PMC 4874402 . PMID 27216521 . ^ Damiano J (2018). "Neolithic Era Tools: Inventing a New Age" . MagellanTV . Archived from the original on 5 January 2021 . Retrieved 9 October 2020 . ^ Deng Y, Wang P (2011). Ancient Chinese inventions . Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6 . OCLC 671710733 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Schifman J (9 July 2018). "The Entire History of Steel" . Popular Mechanics . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Wilkinson, Freddie (9 January 2020). "Industrial Revolution and Technology" . National Geographic Society . Archived from the original on 30 September 2020 . Retrieved 9 October 2020 . ^ Roser, Max ; Ritchie, Hannah (11 May 2013). "Technological Progress" . Our World in Data . Archived from the original on 10 September 2021 . Retrieved 30 July 2022 . ^ Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel" . The Atlantic . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Idinopulos TA (1998). "What Is Religion?" . CrossCurrents . 48 (3): 366–380. ISSN 0011-1953 . JSTOR 24460821 . Archived from the original on 13 October 2020 . Retrieved 30 July 2022 . ^ Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology . 54 (1): 377–402. doi : 10.1146/annurev.psych.54.101601.145024 . PMID 12171998 . ^ King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?" . The Atlantic . Archived from the original on 20 January 2021 . Retrieved 8 October 2020 . ^ Ball P (2015). "Complex societies evolved without belief in all-powerful deity" . Nature News . doi : 10.1038/nature.2015.17040 . S2CID 183474917 . Archived from the original on 16 May 2021 . Retrieved 30 July 2022 . ^ Culotta E (November 2009). "Origins. On the origin of religion". Science . 326 (5954): 784–787. Bibcode : 2009Sci...326..784C . doi : 10.1126/science.326_784 . PMID 19892955 . ^ Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation" . Evolution and Human Behavior . 32 (1): 41–49. doi : 10.1016/j.evolhumbehav.2010.07.008 . ISSN 1090-5138 . Archived from the original on 15 October 2020 . Retrieved 30 July 2022 . ^ Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA – Journal of Death and Dying . 41 (1): 5–22. doi : 10.2190/Q21C-5VED-GYW6-W091 . ISSN 0030-2228 . S2CID 145686249 . ^ McKay R, Whitehouse H (March 2015). "Religion and morality" . Psychological Bulletin . 141 (2): 447–473. doi : 10.1037/a0038455 . PMC 4345965 . PMID 25528346 . ^ Bernhard Nitsche; Marcus Schmücker, eds. (2023). God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality . De Gruyter . doi : 10.1515/9783110698343 . ISBN 978-3-11-069834-3 . ^ Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique" . Journal of Religion and Health (Submitted manuscript). 47 (2): 134–163. doi : 10.1007/s10943-008-9165-2 . PMC 8823950 . PMID 19105008 . S2CID 25349208 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular" . The Guardian . ISSN 0261-3077 . Archived from the original on 1 March 2021 . Retrieved 8 October 2020 . ^ Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe" . Pew Research Center . Archived from the original on 24 November 2019 . Retrieved 8 October 2020 . ^ "The Changing Global Religious Landscape" . Pew Research Center's Religion & Public Life Project . 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 8 October 2020 . ^ Di Christina, Mariette (September 2018). "A Very Human Story: Why Our Species Is Special" . Scientific American . Archived from the original on 24 November 2020 . Retrieved 27 September 2020 . ^ Andersen H , Hepburn B (2020). "Scientific Method" . In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Lo Presti R (2014). "History of science: The first scientist" . Nature . 512 (7514): 250–251. Bibcode : 2014Natur.512..250L . doi : 10.1038/512250a . ISSN 1476-4687 . S2CID 4394696 . ^ Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn . Springer. p. 1. ISBN 978-3-642-18904-3 . OCLC 883392276 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Needham, J ; Wang Ling (1954). Science and civilisation in China . Cambridge University Press. p. 111. ISBN 0-521-05799-X . OCLC 779676 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6 . OCLC 615209781 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017 . Retrieved 3 July 2017 . ^ Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition . Cambridge University Press. pp. 209–210. ISBN 978-1-107-01116-8 . ^ "Branches of Science" (PDF) . University of Chicago . Archived from the original (PDF) on 23 April 2017 . Retrieved 26 June 2017 . ^ "What is Philosophy?" . Department of Philosophy . Florida State University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ "Philosophy" . Definition, Systems, Fields, Schools, & Biographies . Encyclopedia Britannica. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day" . Philosophy and Phenomenological Research . 7 (3): 461. doi : 10.2307/2102800 . JSTOR 2102800 . Archived from the original on 31 March 2022 . Retrieved 30 July 2022 . ^ Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?" . ieet.org . Archived from the original on 4 March 2021 . Retrieved 8 August 2020 . ^ Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?" . European Journal of Information Systems . 27 (3): 263–277. doi : 10.1080/0960085X.2018.1470776 . hdl : 2086/16128 . ISSN 0960-085X . S2CID 64796132 . ^ Schizzerotto A. "Social Stratification" (PDF) . University of Trento . Archived from the original (PDF) on 20 March 2018 . Retrieved 3 July 2017 . ^ Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution . Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9 . OCLC 1082411117 . ^ "Social Role Theory of Sex Differences and Similarities : A Current Appraisal" . The Developmental Social Psychology of Gender . Psychology Press. 2000. pp. 137–188. doi : 10.4324/9781410605245-12 . ISBN 978-1-4106-0524-5 . Archived from the original on 30 April 2021 . Retrieved 10 June 2022 . ^ Blackstone, Amy (2003). "Gender Roles and Society" . In Miller, Julia R.; Lerner, Richard M.; Schiamberg, Lawrence B. (eds.). Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments . Sociology School Faculty Scholarship. Santa barbara, CA: ABC-CLIO. p. 335. Archived from the original on 16 May 2022 . Retrieved 30 July 2022 . ^ Nadal, Kevin L. (2017). The SAGE Encyclopedia of Psychology and Gender . SAGE Publications. p. 401. ISBN 978-1483384276 . Most cultures currently construct their societies based on the understanding of gender binary – the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization. ^ Herdt, Gilbert (2020). "Third Sexes and Third Genders". Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . Princeton, NJ: Princeton University Press. pp. 21–83. ISBN 978-1-942130-52-9 . Retrieved 30 July 2022 . ^ Trumbach, Randolph (1994). "London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture". In Herdt, Gilbert (ed.). Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . New York: Zone (MIT). pp. 111–136. ISBN 978-0-942299-82-3 . ^ Graham, Sharyn (April–June 2001). "Sulawesi's fifth gender" . Inside Indonesia . Archived from the original on 26 November 2014. ^ Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John ; Nieder, Timo O.; T'Sjoen, Guy (2016). "Non-binary or genderqueer genders" . International Review of Psychiatry . 28 (1): 95–102. doi : 10.3109/09540261.2015.1106446 . hdl : 1854/LU-7279758 . PMID 26753630 . S2CID 29985722 . Archived from the original on 26 June 2019 . Retrieved 9 June 2019 . ^ Ananthaswamy, Anil; Douglas, Kate. "The origins of sexism: How men came to rule 12,000 years ago" . New Scientist . Retrieved 7 March 2023 . ^ "What do we mean by "sex" and "gender"?" . World Health Organization . Archived from the original on 30 January 2017 . Retrieved 26 November 2015 . ^ Alters S, Schiff W (2009). Essential Concepts for Healthy Living . Jones & Bartlett Publishers . p. 143. ISBN 978-0-7637-5641-3 . Retrieved 3 January 2018 . ^ Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy . 21 (3): 416–438. doi : 10.1093/oxrep/gri024 . ^ Dobres, Marcia-Anne (27 November 2020). "Gender in the Earliest Human Societies" . In Meade, Teresa A.; Wiesner-Hanks, Merry E. (eds.). A Companion to Global Gender History (1 ed.). Wiley. pp. 183–204. doi : 10.1002/9781119535812.ch11 . ISBN 978-1-119-53580-5 . S2CID 229399965 . Archived from the original on 10 June 2022 . Retrieved 10 June 2022 . ^ "The Nature of Kinship: Overview" . www2.palomar.edu . Archived from the original on 3 December 2020 . Retrieved 24 October 2020 . ^ Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition" . Proceedings of the National Academy of Sciences of the United States of America . 117 (5): 2378–2384. Bibcode : 2020PNAS..117.2378I . doi : 10.1073/pnas.1917716117 . PMC 7007516 . PMID 31964846 . ^ Chandra, Kanchan (2012). Constructivist theories of ethnic politics . Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7 . OCLC 829678440 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389. In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of 'us' and 'them.' In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population. ^ Blackmore E (22 February 2019). "Race and ethnicity: How are they different?" . Culture . Archived from the original on 22 October 2020 . Retrieved 24 October 2020 . ^ Chandra K (2006). "What is Ethnic Identity and Does It Matter?" . Annual Review of Political Science . 9 (1): 397–424. doi : 10.1146/annurev.polisci.9.062404.170715 . ISSN 1094-2939 . ^ Smith AD (1999). Myths and Memories of the Nation . Oxford University Press. pp. 4–7. ^ Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism . 13 (1): 19–35. doi : 10.1111/j.1469-8129.2007.00271.x . ^ Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism . London: Sage. p. 171. ISBN 978-1-4129-0101-7 . ^ Christian D (2004). Maps of Time . University of California Press. ISBN 978-0-520-24476-4 . ^ Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?" . SAPIENS . Archived from the original on 7 August 2020 . Retrieved 24 October 2020 . ^ Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit" . Proceedings of the National Academy of Sciences of the United States of America . 115 (19): E4532–E4540. Bibcode : 2018PNAS..115E4532Z . doi : 10.1073/pnas.1708960115 . PMC 5948950 . PMID 29674447 . S2CID 4993139 . ^ Melina R (14 February 2011). "What Are the Different Types of Governments?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 24 October 2020 . ^ "Democracy Index 2021: less than half the world lives in a democracy" . The Economist Democracy Index . Economist Intelligence Unit . February 10, 2022. ^ Jeannie Evers (23 December 2012). "international organization" . National Geographic Society . Archived from the original on 27 April 2017 . Retrieved 24 October 2020 . ^ Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization . 58 (1): 1–29. doi : 10.1016/j.jebo.2004.03.009 . ISSN 0167-2681 . ^ Gibbons J (11 August 2015). "Why did Neanderthals go extinct?" . Smithsonian Insider . Archived from the original on 12 November 2020 . Retrieved 11 October 2020 . ^ University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?" . www.newswise.com . Archived from the original on 1 February 2021 . Retrieved 11 October 2020 . ^ Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years" . inews.co.uk . Archived from the original on 23 January 2021 . Retrieved 11 October 2020 . ^ Henriques M. "How spices changed the ancient world" . www.bbc.com . Archived from the original on 25 January 2021 . Retrieved 11 October 2020 . ^ Strauss IE (26 February 2016). "The Myth of the Barter Economy" . The Atlantic . Archived from the original on 15 February 2021 . Retrieved 11 October 2020 . ^ "The History of Money" . www.pbs.org . 26 October 1996. Archived from the original on 29 November 2020 . Retrieved 11 October 2020 . ^ "Why do we need economists and the study of economics?" . Federal Reserve Bank of San Francisco . July 2000. Archived from the original on 12 November 2020 . Retrieved 23 October 2020 . ^ Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong" . New Scientist . Archived from the original on 3 February 2021 . Retrieved 24 October 2020 . ^ Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates" . The Atlantic . Archived from the original on 7 May 2021 . Retrieved 7 May 2021 . ^ Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature . 538 (7624): 233–237. Bibcode : 2016Natur.538..233G . doi : 10.1038/nature19758 . PMID 27680701 . S2CID 4454927 . ^ Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF) . Nature . 538 (7624): 180–181. Bibcode : 2016Natur.538..180P . doi : 10.1038/nature19474 . PMID 27680700 . S2CID 4459560 . Archived (PDF) from the original on 20 May 2022 . Retrieved 30 July 2022 . ^ Ferguson RB (1 September 2018). "War Is Not Part of Human Nature" . Scientific American . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Ferguson N (September–October 2006). "The Next War of the World" . Foreign Affairs . Archived from the original on 25 April 2022 . Retrieved 30 July 2022 . ^ Beauchamp, Zack (June 23, 2015). "600 years of war and peace, in one amazing chart" . Vox . External links Listen to this article ( 1 hour and 16 minutes ) This audio file was created from a revision of this article dated 11 January 2022 ( 2022-01-11 ) , and does not reflect subsequent edits. ( Audio help · More spoken articles ) v t e Human evolution Taxonomy ( Hominins ) Last common ancestors Chimpanzee–human Gorilla–human Orangutan–human Gibbon–human Australopithecines Nakalipithecus Orrorin Sahelanthropus Kenyanthropus Ardipithecus A. kadabba A. ramidus Australopithecus A. afarensis A. africanus A. anamensis A. bahrelghazali A. deyiremeda A. garhi A. sediba Paranthropus P. aethiopicus P. boisei P. robustus Humans and proto-humans ( Homo ) Proto-humans H. gautengensis (?) H. habilis H. naledi H. rudolfensis (?) H. tsaichangensis (?) Homo erectus H. e. erectus H. e. georgicus H. e. lantianensis H. e. nankinensis H. e. pekinensis H. e. soloensis H. e. tautavelensis H. e. yuanmouensis Archaic humans H. antecessor Denisovans H. ergaster (?) H. floresiensis H. heidelbergensis H. longi (?) H. luzonensis H. neanderthalensis H. rhodesiensis (?) Modern humans Homo sapiens H. s. sapiens (archaic homo sapiens, anatomically modern humans) Jebel Irhoud H. s. idaltu Cro-Magnon Manot people Tam Pa Ling Red Deer Cave people Ancestors Homo habilis → Homo ergaster / Homo erectus (→ Homo antecessor ) → Homo heidelbergensis → archaic Homo sapiens → Homo sapiens Models General models Hunting Gathering Endurance running Aquatic ape Sexual selection Self-domestication Specific models Diet Cooking Expensive tissue Shore-based Drugs Drunken monkey Evolutionary models of human drug use Stoned ape theory Behavior Killer ape Cooperative eye Life history Grandmother Patriarch Topics Bipedalism Skeleton Muscles Skin color Hair Thermoregulation Speech Language Intelligence Gender roles Origin of modern humans Recent African origin Multiregional origin Archaic admixture Behavioral modernity Early migrations Recent evolution Timelines Human evolution Human prehistory Human timeline Others Theorists Books Fossils Evolutionary anthropology Paleoanthropology Human evolutionary developmental biology Category Commons Evolutionary biology Portal v t e Extant species of family Hominidae (great apes) Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Hominidae Ponginae Pongo (Orangutans) Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Homininae Gorilla (Gorillas) Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Hominini Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Homo (Humans) Human ( H. sapiens ) Category v t e Apes Extant ape species Homo Human ( H. sapiens ) Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Gorilla Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Orangutan Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Gibbon ( family : Hylobatidae) Study of apes Great ape language Dian Fossey Birutė Galdikas Jane Goodall Chimpanzee genome project Human Genome Project Gladys Kalema-Zikusoka Neanderthal genome project Willie Smits Lone Drøscher Nielsen Ian Redmond Elgin Center Iowa Primate Learning Sanctuary Borneo Orangutan Survival Primate archaeology Legal and social status Personhood Research ban Kinshasa Declaration on Great Apes Great Ape Project Great Apes Survival Partnership International Primate Day Nonhuman Rights Project Related Primate List of individual apes (non-human) Apes in space (non-human) Bigfoot Bushmeat Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor Gibbon–human last common ancestor List of fictional primates (non-human) Great apes Human evolution Monkey Day Mythic humanoids Yeren Yeti Yowie Category Humans at Wikipedia's sister projects : Definitions from Wiktionary Media from Commons Quotations from Wikiquote Texts from Wikisource Taxa from Wikispecies Taxon identifiers Homo sapiens Wikidata : Q15978631 ADW : Homo_sapiens BOLD : 12439 CoL : 6MB3T EoL : 327955 EPPO : HOMXSA GBIF : 2436436 iNaturalist : 43584 IRMNG : 10857762 ITIS : 180092 MDD : 1000718 MSW : 12100795 NBN : NHMSYS0000376773 NCBI : 9606 NZOR: d83185ac-1aa6-4f59-8645-fe8c040857b3 Observation.org : 83981 OBIS : 1455977 Open Tree of Life : 770315 Paleobiology Database : 83088 TSA : 8319 WoRMS : 1455977 ZooBank : 58D31D52-713D-44B4-9FE9-CB2D9249C422 Authority control databases International FAST National France BnF data Germany Israel Czech Republic Korea Other Encyclopedia of Modern Ukraine NARA İslâm Ansiklopedisi Retrieved from " https://en.wikipedia.org/w/index.php?title=Human&oldid=1221314650 " Categories : Hominini Humans Apex predators Mammals described in 1758 Taxa named by Carl Linnaeus Tool-using mammals Cosmopolitan mammals Hidden categories: CS1 maint: DOI inactive as of March 2024 Articles with short description Short description is different from Wikidata Good articles Wikipedia indefinitely semi-protected pages Wikipedia indefinitely move-protected pages Articles with 'species' microformats Articles containing Latin-language text Articles containing Old French (842-ca. 1400)-language text Articles containing French-language text Articles containing potentially dated statements from 2018 All articles containing potentially dated statements Articles with hAudio microformats Spoken articles Pages using Sister project links with wikidata mismatch Pages using Sister project links with default search Taxonbars desynced from Wikidata Taxonbars on possible non-taxon pages Taxonbars with 20–24 taxon IDs Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with GND identifiers Articles with J9U identifiers Articles with NKC identifiers Articles with NLK identifiers Articles with EMU identifiers Articles with NARA identifiers Articles with TDVİA identifiers Articles containing video clips This page was last edited on 29 April 2024, at 05:20 (UTC) . Text is available under the Creative Commons Attribution-ShareAlike License 4.0 ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy . Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. , a non-profit organization. Privacy policy About Wikipedia Disclaimers Contact Wikipedia Code of Conduct Developers Statistics Cookie statement Mobile view
Contents move to sidebar hide (Top) 1 Etymology and definition 2 Evolution 3 History Toggle History subsection 3.1 Prehistory 3.2 Ancient 3.3 Medieval 3.4 Modern 3.5 Contemporary 4 Habitat and population 5 Biology Toggle Biology subsection 5.1 Anatomy and physiology 5.2 Genetics 5.3 Life cycle 5.4 Diet 5.5 Biological variation 6 Psychology Toggle Psychology subsection 6.1 Sleep and dreaming 6.2 Consciousness and thought 6.3 Motivation and emotion 6.4 Sexuality and love 7 Culture Toggle Culture subsection 7.1 Language 7.2 The arts 7.3 Tools and technologies 7.4 Religion and spirituality 7.5 Science and philosophy 8 Society Toggle Society subsection 8.1 Gender 8.2 Kinship 8.3 Ethnicity 8.4 Government and politics 8.5 Trade and economics 8.6 Conflict 9 See also 10 Notes 11 References 12 External links Toggle the table of contents Human 213 languages Afrikaans Alemannisch አማርኛ अंगिका العربية Aragonés ܐܪܡܝܐ Armãneashti অসমীয়া Asturianu Atikamekw अवधी Avañe'ẽ Авар Aymar aru Azərbaycanca تۆرکجه Basa Bali বাংলা Banjar 閩南語 / Bân-lâm-gú Basa Banyumasan Башҡортса Беларуская Беларуская (тарашкевіца) भोजपुरी Bikol Central Български Boarisch བོད་ཡིག Bosanski Brezhoneg Буряад Català Чӑвашла Cebuano Čeština ChiShona ChiTumbuka Corsu Cymraeg Dagbanli Dansk الدارجة Davvisámegiella Deutsch डोटेली Eesti Ελληνικά Эрзянь Español Esperanto Euskara فارسی Fiji Hindi Føroyskt Frysk Furlan Gaeilge Gàidhlig Galego ГӀалгӀай 贛語 گیلکی ગુજરાતી 客家語/Hak-kâ-ngî 한국어 Hausa Հայերեն हिन्दी Hrvatski Ido Igbo Ilokano Bahasa Indonesia ᐃᓄᒃᑎᑐᑦ / inuktitut Ирон IsiXhosa IsiZulu Íslenska עברית Jawa ಕನ್ನಡ Kapampangan ქართული कॉशुर / کٲشُر Қазақша Kernowek Kiswahili Коми Kongo Kreyòl ayisyen Kriyòl gwiyannen Kurdî Кыргызча Ladin Лакку ລາວ Latgaļu Latina Latviešu Лезги Lietuvių Ligure Limburgs Lingála Lingua Franca Nova La .lojban. Luganda Magyar मैथिली Македонски Malagasy മലയാളം Malti मराठी მარგალური مصرى مازِرونی Bahasa Melayu ꯃꯤꯇꯩ ꯂꯣꯟ Minangkabau 閩東語 / Mìng-dĕ̤ng-ngṳ̄ Mirandés Мокшень Монгол မြန်မာဘာသာ Nāhuatl Nederlands Nedersaksies नेपाली नेपाल भाषा 日本語 Нохчийн Nordfriisk Norfuk / Pitkern Norsk bokmål Norsk nynorsk Occitan Олык марий ଓଡ଼ିଆ Oʻzbekcha / ўзбекча ਪੰਜਾਬੀ पालि پنجابی Papiamentu پښتو Patois Перем коми ភាសាខ្មែរ Piemontèis Plattdüütsch Polski Português Qaraqalpaqsha Ripoarisch Română Romani čhib Rumantsch Runa Simi Русский Саха тыла Sakizaya संस्कृतम् ᱥᱟᱱᱛᱟᱲᱤ Scots Shqip Sicilianu සිංහල Simple English سنڌي Slovenčina Slovenščina Ślůnski Soomaaliga کوردی Српски / srpski Srpskohrvatski / српскохрватски Sunda Suomi Svenska Tagalog தமிழ் Taclḥit Taqbaylit Татарча / tatarça Tayal తెలుగు ไทย Тоҷикӣ Türkçe Türkmençe Twi Tyap Українська اردو ئۇيغۇرچە / Uyghurche Vahcuengh Vepsän kel’ Tiếng Việt Võro Walon 文言 West-Vlams Winaray 吴语 Xitsonga ייִדיש Yorùbá 粵語 Zazaki Žemaitėška 中文 Edit links Article Talk English Read View source View history Tools Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote From Wikipedia, the free encyclopedia Species of hominid in the genus Homo Several terms redirect here. For other uses, see Human (disambiguation) , Mankind (disambiguation) , Humankind (disambiguation) , Human Race (disambiguation) , Human Being (disambiguation) , and Homo sapiens (disambiguation) . Human Temporal range: 0.3–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Chibanian – present Male (left) and female (right) adult humans, Thailand , 2007 Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Infraorder: Simiiformes Family: Hominidae Subfamily: Homininae Tribe: Hominini Genus: Homo Species: H. sapiens Binomial name Homo sapiens Linnaeus , 1758 Homo sapiens population density (2005) Humans ( Homo sapiens ) or modern humans are the most common and widespread species of primate , and the last surviving species of the genus Homo . They are great apes characterized by their hairlessness , bipedalism , and high intelligence . Humans have large brains , enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools , and form complex social structures and civilizations . Humans are highly social , with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states . As such, social interactions between humans have established a wide variety of values, social norms , languages , and traditions (collectively termed institutions ), each of which bolsters human society . Humans are also highly curious : the desire to understand and influence phenomena has motivated humanity's development of science , technology , philosophy , mythology , religion , and other frameworks of knowledge ; humans also study themselves through such domains as anthropology , social science , history , psychology , and medicine . As of April 2024, there are estimated to be more than 8 billion humans alive . Although some scientists equate the term "humans" with all members of the genus Homo , in common usage it generally refers to Homo sapiens , the only extant member. All other members of the genus Homo , which are now extinct, are known as archaic humans , and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa , they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence , interbreeding with Homo sapiens , or inability to adapt to climate change. For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution , which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement ; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change . Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle. Genes and the environment influence human biological variation in visible characteristics, physiology , disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic : generally, males have greater body strength and females have a higher body fat percentage. At puberty , humans develop secondary sex characteristics . Females are capable of pregnancy , usually between puberty, at around 12 years old, and menopause , around the age of 50. Humans are omnivorous , capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus . Humans can survive for up to eight weeks without food and several days without water . Humans are generally diurnal , sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death . Often, both the mother and the father provide care for their children, who are helpless at birth . Humans have a large, highly developed, and complex prefrontal cortex , the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory ; they have flexible facial expressions, self-awareness , and a theory of mind . The human mind is capable of introspection , private thought , imagination , volition , and forming views on existence . This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language . Etymology and definition Further information: Names for the human species and Human taxonomy Carl Linnaeus coined the name Homo sapiens All modern humans are classified into the species Homo sapiens , coined by Carl Linnaeus in his 1735 work Systema Naturae . The generic name " Homo " is a learned 18th-century derivation from Latin homō , which refers to humans of either sex. The word human can refer to all members of the Homo genus. The name " Homo sapiens " means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals , should be included as a separate species of humans or as a subspecies of H. sapiens . Human is a loanword of Middle English from Old French humain , ultimately from Latin hūmānus , the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity ) as well as to human males. It may also refer to individuals of either sex. Despite the fact that the word animal is colloquially used as an antonym for human , and contrary to a common biological misconception , humans are animals. The word person is often used interchangeably with human , but philosophical debate exists as to whether personhood applies to all humans or all sentient beings , and further if one can lose personhood (such as by going into a persistent vegetative state ). Evolution Main article: Human evolution Humans are apes ( superfamily Hominoidea ). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo ), then gorillas (genus Gorilla ), and finally, chimpanzees and bonobos (genus Pan ). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct. Reconstruction of Lucy , the first Australopithecus afarensis skeleton found The genus Homo evolved from Australopithecus . Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus . The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia , and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster ) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan . Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis , the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier. The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second ( Southern Dispersal ) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii , Easter Island , Madagascar , and New Zealand in the years 300 to 1280 CE. Human evolution was not a simple linear or branched progression but involved interbreeding between related species . Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans , may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans. Human evolution is characterized by a number of morphological , developmental , physiological , and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees . The most significant of these adaptations are hairlessness , obligate bipedalism, increased brain size and decreased sexual dimorphism ( neoteny ). The relationship between all these changes is the subject of ongoing debate. Hominoidea (hominoids, apes ) Hylobatidae ( gibbons ) Hominidae (hominids, great apes ) Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans) History Main article: Human history Prehistory Main article: Prehistory Overview map of the peopling of the world by early human migration during the Upper Paleolithic , following the Southern Dispersal paradigm Until about 12,000 years ago, all humans lived as hunter-gatherers . The Neolithic Revolution (the invention of agriculture ) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea , and the Sahel and West Savanna regions of Africa. Access to food surplus led to the formation of permanent human settlements , the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations . Ancient Main article: Ancient history Great Pyramids of Giza , Egypt An urban revolution took place in the 4th millennium BCE with the development of city-states , particularly Sumerian cities located in Mesopotamia . It was in these cities that the earliest known form of writing, cuneiform script , appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation . They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture , Minoans and the Shang dynasty , rose to prominence in new areas. The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages . During this period iron started replacing bronze, leading to the Iron Age . In the 5th century BCE, history started being recorded as a discipline , which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars . In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire 's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions. Medieval Main article: Post-classical history Medieval French manuscript illustration of the three classes of medieval society from the 13th-century Li Livres dou Santé Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages . During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age , inspiring achievements in architecture , the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England , the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims . In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast . Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific. Modern Main articles: Early modern period and Late modern period James Watt 's steam engine The early modern period in Europe and the Near East ( c. 1450 –1800) began with the final defeat of the Byzantine Empire , and the rise of the Ottoman Empire . Meanwhile, Japan entered the Edo period , the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance , starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas . This expansion led to the Atlantic slave trade and the genocide of Native American peoples . This period also marked the Scientific Revolution , with great advances in mathematics , mechanics , astronomy and physiology . The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology , major innovations in transport and energy development . The United States of America underwent great change, going from a small group of colonies to one of the global superpowers . The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World , while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania. A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War , one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War , involving almost all of the world's countries . The war's destruction led to the collapse of most global empires, leading to widespread decolonization. Contemporary Main article: Contemporary history Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race , ending in the collapse of the Soviet Union. The current Information Age , spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected. Habitat and population Further information: Human geography and Demography Population statistics Choropleth showing Population density (people per square kilometer) estimates by 30 arc-second grid in 2020 World population 8.1 billion Population density 16/km (41/sq mi) by total area 54/km (140/sq mi) by land area Largest cities Tokyo , Delhi , Shanghai , São Paulo , Mexico City , Cairo , Mumbai , Beijing , Dhaka , Osaka , New York - Newark , Karachi , Buenos Aires , Chongqing , Istanbul , Kolkata , Manila , Lagos , Rio de Janeiro , Tianjin , Kinshasa , Guangzhou , Los Angeles - Long Beach - Santa Ana , Moscow , Shenzhen , Lahore , Bangalore , Paris , Jakarta , Chennai , Lima , Bogota , Bangkok , London Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence , such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation , urban planning , construction, deforestation and desertification . Human settlements continue to be vulnerable to natural disasters , especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics , increasing knowledge or enhancing the exchange of resources. Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms , although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa , India , Russia , Australia , Fiji , United States and Brazil (each located in a different biogeographical realm). By using advanced tools and clothing , humans have been able to extend their tolerance to a wide variety of temperatures, humidities , and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest , arid desert , extremely cold arctic regions , and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth 's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%). Within the last century, humans have explored challenging environments such as Antarctica, the deep sea , and outer space . Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific , military , or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft . Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station . Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%. Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues , first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals. In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums . Humans have had a dramatic effect on the environment . They are apex predators , being rarely preyed upon by other species. Human population growth , industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life. Biology Anatomy and physiology Main article: Human body Basic anatomical features of female and male humans. These models have had body hair and male facial hair removed and head hair trimmed. Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.3 2.1.2.3 . Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth . Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars , with some individuals having them congenitally absent. Humans share with chimpanzees a vestigial tail, appendix , flexible shoulder joints, grasping fingers and opposable thumbs . Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling , hearing and digesting proteins . While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair , most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet. It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged . Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals. Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger. Genetics Main article: Human genetics A graphical representation of the standard human karyotype , including both the female (XX) and male (XY) sex chromosomes. Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes , each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes . Like other mammals, humans have an XY sex-determination system , so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood. While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years. The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms . African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas . By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA , which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve , must have lived around 90,000 to 200,000 years ago. Life cycle See also: Childbirth and Life expectancy A 10 mm human embryo at 5 weeks Most human reproduction takes place by internal fertilization via sexual intercourse , but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus . Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions. Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries. Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth , humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy , childhood , adolescence , adulthood and old age . The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis ), rather than by continuing to bear children into old age. The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018 , the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic , it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world , the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide. Human life stages Infant boy and girl Boy and girl before puberty ( children ) Adolescent male and female Adult man and woman Elderly man and woman Diet Main article: Human nutrition Humans living in Bali , Indonesia , preparing a meal Humans are omnivorous , capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous . In some cases, dietary restrictions in humans can lead to deficiency diseases ; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science . Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game , which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus . Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture , a gradual process called the Neolithic Revolution . These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture. In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation . Childhood malnutrition is also common and contributes to the global burden of disease . However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries . Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an " obesity epidemic ." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet. Biological variation Main article: Human genetic variation A Libyan , a Nubian , a Syrian , and an Egyptian , drawing by an unknown artist after a mural of the tomb of Seti I There is biological variation in the human species – with traits such as blood type , genetic diseases , cranial features , facial features , organ systems , eye color , hair color and texture , height and build , and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin , and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet , exercise, and sleep patterns . A variety of human hair colors; from top left, clockwise: black , brown , blonde , white , red . There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk . Sickle cell anemia , which may provide increased resistance to malaria , is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions , tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes . Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau . Human hair ranges in color from red to blond to brown to black , which is the most frequent. Hair color depends on the amount of melanin , with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach , or even nearly white or colorless in cases of albinism . It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D , which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation. There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other. Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa , and particularly West Africa , have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans. Humans are a gonochoric species, meaning they are divided into male and female sexes . The greatest degree of genetic variation exists between males and females . While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation . As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare. Psychology Main article: Psychology Drawing of the human brain , showing several important structures The human brain , the focal point of the central nervous system in humans, controls the peripheral nervous system . In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion , it is also the locus of "higher" order functioning such as thought , reasoning , and abstraction . These cognitive processes constitute the mind , and, along with their behavioral consequences, are studied in the field of psychology . Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition . This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to. There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in " mental time travel ". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind . Sleep and dreaming Main articles: Sleep and Dream Humans are generally diurnal . The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort. During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep . The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming , where the dreamer is self-aware . Dreams can at times make a creative thought occur or give a sense of inspiration . Consciousness and thought Main articles: Consciousness and Cognition Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection , private thought , imagination and volition . It now often includes some kind of experience , cognition , feeling or perception . It may be 'awareness', or ' awareness of awareness ', or self-awareness . There might be different levels or orders of consciousness , or different kinds of consciousness, or just one kind with different features. The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses , and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition , the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development . Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population. Motivation and emotion Main articles: Motivation and Emotion Illustration of grief from Charles Darwin 's 1872 book The Expression of the Emotions in Man and Animals Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization . Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure . They are often intertwined with mood , temperament , personality , disposition , creativity , and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal. Emotional experiences perceived as pleasant , such as joy , interest or contentment , contrast with those perceived as unpleasant , like anxiety , sadness , anger , and despair . Happiness , or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects , while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life . Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted. Sexuality and love Main articles: Human sexuality and Love Human parents often display familial love for their children. For humans, sexuality involves biological , erotic , physical , emotional , social , or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions , including the human sexual response cycle . Sexuality also affects and is affected by cultural, political, legal, philosophical, moral , ethical , and religious aspects of life. Sexual desire, or libido , is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often. Humans can fall anywhere along a continuous scale of sexual orientation , although most humans are heterosexual . While homosexual behavior occurs in some other animals , only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation , as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well. Love most commonly refers to a feeling of strong attraction or emotional attachment . It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine , norepinephrine , serotonin and other chemicals stimulate the brain's pleasure center , leading to side effects such as increased heart rate , loss of appetite and sleep , and an intense feeling of excitement . Culture Main articles: Culture and Cultural universal Human society statistics Most widely spoken languages English , Mandarin Chinese , Hindi , Spanish , Standard Arabic , Bengali , French , Russian , Portuguese , Urdu Most practiced religions Christianity , Islam , Hinduism , Buddhism , folk religions , Sikhism , Judaism , unaffiliated Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the " folk physics " required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning . Language Main article: Language Principal language families of the world (and in some cases geographic groups of families). For greater detail, see Distribution of languages in the world . While many species communicate , language is unique to humans, a defining feature of humanity, and a cultural universal . Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement , using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors. Language differs from other forms of communication in that it is modality independent ; the same meanings can be conveyed through different media, audibly in speech , visually by sign language or writing, and through tactile media such as braille . Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct . The arts Main article: The arts Human arts can take many forms including visual , literary , and performing . Visual art can range from paintings and sculptures to film , fashion design , and architecture . Literary arts can include prose , poetry , and dramas . The performing arts generally involve theatre , music , and dance . Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation , video games , and medicine . As well as providing entertainment and transferring knowledge, the arts are also used for political purposes . The Deluge tablet of the Gilgamesh epic in Akkadian Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage. Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures . There exists a wide variety of music genres and ethnic musics ; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment . Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain. Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh , first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation. Tools and technologies Main articles: Tool and Technology The SCMaglev , the fastest train in the world clocking in at 603 km/h (375 mph) as of 2015 Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated , thus proving essential in the development of agriculture – what is known as the Neolithic Revolution . China developed paper , the printing press , gunpowder , the compass and other important inventions . The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel , which is used in railways , skyscrapers and many other products. This coincided with the Industrial Revolution , where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially , with major innovations in the 20th century including: electricity , penicillin , semiconductors , internal combustion engines , the Internet , nitrogen fixing fertilisers , airplanes , computers , automobiles , contraceptive pills , nuclear fission , the green revolution , radio , scientific plant breeding , rockets , air conditioning , television and the assembly line . Religion and spirituality Main articles: Religion and Spirituality Shango , the Orisha of fire, lightning, and thunder, in the Yoruba religion , depicted on horseback Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural , sacred or divine , and practices, values , institutions and rituals associated with such belief. Some religions also have a moral code . The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago ). It may have evolved to play a role in helping enforce and encourage cooperation between humans. Religion manifests in diverse forms. Religion can include a belief in life after death , the origin of life , the nature of the universe ( religious cosmology ) and its ultimate fate ( eschatology ), and moral or ethical teachings . Views on transcendence and immanence vary substantially; traditions variously espouse monism , deism , pantheism , and theism (including polytheism and monotheism ). Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims , Hindus and Buddhists . As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious , including those with no religious beliefs or no identity with any religion. Science and philosophy Main articles: Science and Philosophy The Dunhuang map , a star map showing the North Polar region. China circa 700. An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy. Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period . Other early advances in science came from the Han dynasty in China and during the Islamic Golden Age . The scientific revolution , near the end of the Renaissance , led to the emergence of modern science . A chain of events and influences led to the development of the scientific method , a process of observation and experimentation that is used to differentiate science from pseudoscience . An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition . All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics ), which are concerned with formal systems , the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics , chemistry , biology ) and social sciences (e.g., psychology , economics, sociology). Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics , epistemology , logic , and axiology (which includes ethics and aesthetics ). Society Main article: Society Humans often live in family-based social structures Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power , reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies . Gender Main article: Gender Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex . The most common categorisation is a gender binary of men and women . Some societies recognise a third gender , or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female. Gender roles are often associated with a division of norms , practices , dress , behavior , rights , duties , privileges , status , and power , with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct , gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic , while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal. Kinship Main article: Kinship All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants ( consanguinity ), and relations through marriage ( affinity ). There is also a third type applied to godparents or adoptive children ( fictive ). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance . All societies have rules of incest taboo , according to which marriage between certain kinds of kin relations is prohibited, and some also have rules of preferential marriage with certain kin relations. Ethnicity Main article: Ethnic group Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry , language , history , society , culture , nation , religion , or social treatment within their residing area. Ethnicity is separate from the concept of race , which is based on physical characteristics, although both are socially constructed . Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries. Government and politics Main articles: Government and Politics The United Nations headquarters in New York City, which houses one of the world's largest political organizations As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances. Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy , 17% in a hybrid regime , and 37% in an authoritarian regime . Many countries belong to international organizations and alliances ; the largest of these is the United Nations , with 193 member states . Trade and economics Main articles: Trade and Economics The Silk Road (red) and spice trade routes (blue) Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian . The first truly international trade routes were around the spice trade through the Roman and medieval periods. Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities ; the oldest being in the form of cattle and the most widely used being cowrie shells . Money has since evolved into governmental issued coins , paper and electronic money . Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population. Conflict Main article: Conflict (process) American troops landing at Normandy , WWII. Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered , rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations, with rates of homicide about 0.01% in societies that have legal systems and strong cultural attitudes against violence. The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war ) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict. See also Mammals portal Evolutionary biology portal Science portal List of human evolution fossils Timeline of human evolution Notes ^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects. ^ Cities with over 10 million inhabitants as of 2018. ^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that. References ^ Groves CP (2005). Wilson DE , Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4 . OCLC 62265494 . ^ Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences . 149 (1): 109–114. JSTOR 4065043 . ^ Porkorny (1959). IEW . s.v. "g'hðem" pp. 414–116. ^ "Homo" . Dictionary.com Unabridged (v 1.1) . Random House. 23 September 2008. Archived from the original on 27 September 2008. ^ Barras, Colin (11 January 2016). "We don't know which species should be classed as 'human' " . BBC . Archived from the original on 26 August 2021 . Retrieved 31 March 2021 . ^ Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758" . Proceedings of the Academy of Natural Sciences of Philadelphia . 149 : 109–114. ISSN 0097-3157 . JSTOR 4065043 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . ^ OED . s.v. "human". ^ "Man" . Merriam-Webster Dictionary . Archived from the original on 22 September 2017 . Retrieved 14 September 2017 . Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination ^ "Thesaurus results for human" . Merriam-Webster Dictionary . Archived from the original on 28 June 2022 . Retrieved 21 May 2022 . ^ "Misconceptions about evolution – Understanding Evolution" . University of California, Berkeley . 19 September 2021. Archived from the original on 6 June 2022 . Retrieved 21 May 2022 . ^ "Concept of Personhood" . University of Missouri School of Medicine . Archived from the original on 4 March 2021 . Retrieved 4 July 2021 . ^ Tuttle RH (4 October 2018). "Hominoidea: conceptual history" . In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology . Hoboken , New Jersey , United States : John Wiley & Sons, Inc. pp. 1–2. doi : 10.1002/9781118584538.ieba0246 . ISBN 978-1-118-58442-2 . S2CID 240125199 . Retrieved 26 May 2021 . ^ Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution . 30 (3): 260–266. Bibcode : 1990JMolE..30..260G . doi : 10.1007/BF02099995 . PMID 2109087 . S2CID 2112935 . ^ Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets" . Molecular Biology and Evolution . 14 (3): 248–265. doi : 10.1093/oxfordjournals.molbev.a025761 . PMID 9066793 . ^ MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes" . Evolution pages . Archived from the original on 9 August 2011 . Retrieved 18 May 2006 . ^ McNulty, Kieran P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?" . Nature Education Knowledge . Archived from the original on 10 January 2016 . Retrieved 11 June 2022 . ^ Strait DS (September 2010). "The Evolutionary History of the Australopiths" . Evolution: Education and Outreach . 3 (3): 341–352. doi : 10.1007/s12052-010-0249-6 . ISSN 1936-6434 . S2CID 31979188 . ^ Dunsworth HM (September 2010). "Origin of the Genus Homo" . Evolution: Education and Outreach . 3 (3): 353–366. doi : 10.1007/s12052-010-0247-8 . ISSN 1936-6434 . S2CID 43116946 . ^ Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1698): 20150248. doi : 10.1098/rstb.2015.0248 . PMC 4920303 . PMID 27298460 . S2CID 20267830 . ^ Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia" . Science . 347 (6228): 1352–1355. Bibcode : 2015Sci...347.1352V . doi : 10.1126/science.aaa1343 . PMID 25739410 . ^ Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature . 559 (7715): 608–612. Bibcode : 2018Natur.559..608Z . doi : 10.1038/s41586-018-0299-4 . PMID 29995848 . S2CID 49670311 . ^ Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF) . Nature . 546 (7657): 289–292. Bibcode : 2017Natur.546..289H . doi : 10.1038/nature22336 . PMID 28593953 . S2CID 256771372 . Archived (PDF) from the original on 8 January 2020 . Retrieved 30 July 2022 . ^ "Out of Africa Revisited". Science (This Week in Science ). 308 (5724): 921. 13 May 2005. doi : 10.1126/science.308.5724.921g . ISSN 0036-8075 . S2CID 220100436 . ^ Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature . 423 (6941): 692–693, 695. Bibcode : 2003Natur.423..692S . doi : 10.1038/423692a . PMID 12802315 . S2CID 26693109 . ^ Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?" . actionbioscience . Washington, DC: American Institute of Biological Sciences . Archived from the original on 17 June 2021 . Retrieved 23 November 2009 . ^ Marean, Curtis; et al. (2007). "Early human use of marine resources and pigment in South Africa during the Middle Pleistocene" (PDF) . Nature . 449 (7164): 905–908. Bibcode : 2007Natur.449..905M . doi : 10.1038/nature06204 . PMID 17943129 . S2CID 4387442 . Archived (PDF) from the original on 2023-05-25 . Retrieved 2023-01-07 . ^ Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB (2018). "Long-distance stone transport and pigment use in the earliest Middle Stone Age" . Science . 360 (6384): 90–94. Bibcode : 2018Sci...360...90B . doi : 10.1126/science.aao2646 . PMID 29545508 . ^ Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology . 26 (6): 827–833. Bibcode : 2016CBio...26..827P . doi : 10.1016/j.cub.2016.01.037 . hdl : 2440/114930 . PMID 26853362 . S2CID 140098861 . ^ Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture" . Genome Research . 25 (4): 459–466. doi : 10.1101/gr.186684.114 . PMC 4381518 . PMID 25770088 . ^ Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia" . Science . 331 (6016): 453–456. Bibcode : 2011Sci...331..453A . doi : 10.1126/science.1199113 . PMID 21273486 . S2CID 20296624 . Archived from the original on 27 April 2011 . Retrieved 1 May 2011 . ^ Rincon P (27 January 2011). "Humans 'left Africa much earlier' " . BBC News . Archived from the original on 9 August 2012. ^ Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature . 547 (7663): 306–310. Bibcode : 2017Natur.547..306C . doi : 10.1038/nature22968 . hdl : 2440/107043 . PMID 28726833 . S2CID 205257212 . ^ Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF) . University of Waikato . Archived (PDF) from the original on 22 May 2010 . Retrieved 29 April 2010 . ^ Appenzeller T (May 2012). "Human migrations: Eastern odyssey" . Nature . 485 (7396): 24–26. Bibcode : 2012Natur.485...24A . doi : 10.1038/485024a . PMID 22552074 . ^ Reich D , Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" . Nature . 468 (7327): 1053–1060. Bibcode : 2010Natur.468.1053R . doi : 10.1038/nature09710 . hdl : 10230/25596 . PMC 4306417 . PMID 21179161 . ^ Hammer MF (May 2013). "Human Hybrids" (PDF) . Scientific American . 308 (5): 66–71. Bibcode : 2013SciAm.308e..66H . doi : 10.1038/scientificamerican0513-66 . PMID 23627222 . Archived from the original (PDF) on 24 August 2018. ^ Yong E (July 2011). "Mosaic humans, the hybrid species" . New Scientist . 211 (2823): 34–38. Bibcode : 2011NewSc.211...34Y . doi : 10.1016/S0262-4079(11)61839-3 . ^ Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology . 43 (1): 1–11. doi : 10.1007/s11692-015-9348-1 . S2CID 14329491 . ^ Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans" . Genome Research . 20 (5): 547–553. doi : 10.1101/gr.076000.108 . PMC 2860157 . PMID 20439435 . ^ Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans" . Science . 334 (6052): 89–94. Bibcode : 2011Sci...334...89A . doi : 10.1126/science.1209202 . PMC 3677943 . PMID 21868630 . ^ Sandel, Aaron A. (30 July 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness" . American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . Archived from the original on 22 July 2023 . Retrieved 22 July 2023 . ^ Boyd R , Silk JB (2003). How Humans Evolved . New York: Norton . ISBN 978-0-393-97854-4 . ^ Little, Michael A.; Blumler, Mark A. (2015). "Hunter-Gatherers" . In Muehlenbein, Michael P. (ed.). Basics in Human Evolution . Boston: Academic Press. pp. 323–335. ISBN 978-0-12-802652-6 . Archived from the original on 3 July 2022 . Retrieved 30 July 2022 . ^ Scarre, Chris (2018). "The world transformed: from foragers and farmers to states and empires". In Scarre, Chris (ed.). The Human Past: World Prehistory and the Development of Human Societies (4th ed.). London: Thames & Hudson . pp. 174–197. ISBN 978-0-500-29335-5 . ^ Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe . Walnut Creek, CA: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5 . OCLC 855969933 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society . Elsevier. pp. 103–131. doi : 10.1016/B978-0-12-805247-1.00006-X . ISBN 978-0-12-805247-1 . ^ He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China" . The Holocene . 27 (12): 1885–1898. Bibcode : 2017Holoc..27.1885H . doi : 10.1177/0959683617708455 . S2CID 133660098 . Archived from the original on 20 November 2021 . Retrieved 30 July 2022 . ^ Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago" . Proceedings of the National Academy of Sciences of the United States of America . 106 (18): 7367–7372. Bibcode : 2009PNAS..106.7367L . doi : 10.1073/pnas.0900158106 . PMC 2678631 . PMID 19383791 . ^ Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea" . Science . 301 (5630): 189–193. doi : 10.1126/science.1085255 . PMID 12817084 . S2CID 10644185 . ^ Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication" . Science Advances . 5 (5): eaaw1947. Bibcode : 2019SciA....5.1947S . doi : 10.1126/sciadv.aaw1947 . PMC 6527260 . PMID 31114806 . ^ Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF) . Current Anthropology . 58 (5): 673–683. doi : 10.1086/693898 . S2CID 149402650 . Archived (PDF) from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science . 38 (2): 312–322. Bibcode : 2011JArSc..38..312M . doi : 10.1016/j.jas.2010.09.007 . ^ Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries . Cengage Learning. ISBN 978-1-285-66153-7 . Archived from the original on 27 February 2021 . Retrieved 11 July 2015 . ^ Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500 . Cenpage Learning. ISBN 978-1-285-98299-1 . Archived from the original on 10 August 2023 . Retrieved 11 July 2015 . ^ Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization . San Francisco: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3 . Archived from the original on 10 August 2023 . Retrieved 30 July 2022 . ^ Garfinkle, Steven J. (2013). "Ancient Near Eastern City-States". In Peter Fibiger Bang ; Walter Scheidel (eds.). The Oxford Handbook of the State in the Ancient Near East and Mediterranean . Oxford Academic. pp. 94–119. doi : 10.1093/oxfordhb/9780195188318.013.0004 . ISBN 978-0-19-518831-8 . ^ Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi : 10.1002/9781119193814.ch2 . ISBN 978-1-119-19329-6 . S2CID 216180781 . ^ Robinson A (October 2015). "Ancient civilization: Cracking the Indus script" . Nature . 526 (7574): 499–501. Bibcode : 2015Natur.526..499R . doi : 10.1038/526499a . PMID 26490603 . S2CID 4458743 . ^ Crawford H (2013). "Trade in the Sumerian world". The Sumerian World . Routledge. pp. 447–461. ISBN 978-1-136-21911-5 . ^ Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles" . Acta Archaeologica Academiae Scientiarum Hungaricae . 69 (2): 271–298. doi : 10.1556/072.2018.69.2.3 . ISSN 0001-5210 . S2CID 115685157 . Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Pryor FL (1985). "The Invention of the Plow" . Comparative Studies in Society and History . 27 (4): 727–743. doi : 10.1017/S0010417500011749 . ISSN 0010-4175 . JSTOR 178600 . S2CID 144840498 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Carter R (2012). "19. Watercraft ". In Potts DT (ed.). A companion to the archaeology of the ancient Near East . Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0 . Archived from the original on 28 April 2015 . Retrieved 8 February 2014 . ^ Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction . CUP Archive. p. 1. ISBN 978-0-521-40340-5 . ^ Robson E (2008). Mathematics in ancient Iraq: A social history . Princeton University Press. pp. xxi. ^ Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza" . Technology and Culture . 44 (2): 340–354. doi : 10.1353/tech.2003.0063 . ISSN 0040-165X . JSTOR 25148110 . S2CID 109998651 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Voosen P (August 2018). "New geological age comes under fire". Science . 361 (6402): 537–538. Bibcode : 2018Sci...361..537V . doi : 10.1126/science.361.6402.537 . PMID 30093579 . S2CID 51954326 . ^ Saggs HW (2000). Babylonians . Univ of California Press. p. 7. ISBN 978-0-520-20222-1 . ^ Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory . 12 (4): 335–364. doi : 10.1007/s10816-005-8460-4 . ISSN 1573-7764 . S2CID 53393440 . ^ Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans" . Nature . 548 (7666): 214–218. Bibcode : 2017Natur.548..214L . doi : 10.1038/nature23310 . PMC 5565772 . PMID 28783727 . ^ Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC . Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8 . ^ Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change . 6 (4): 369–382. Bibcode : 2015WIRCC...6..369K . doi : 10.1002/wcc.345 . S2CID 128460316 . ^ Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science . 39 (6): 1862–1870. Bibcode : 2012JArSc..39.1862D . doi : 10.1016/j.jas.2012.01.029 . ^ Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory . Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi : 10.1007/978-1-4419-6633-9_11 . ISBN 978-1-4419-6633-9 . ^ Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography . United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1 . ^ Beard M (2 October 2015). "Why ancient Rome matters to the modern world" . The Guardian . Archived from the original on 14 April 2021 . Retrieved 17 April 2021 . ^ Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece" . Stanford University . Archived from the original on 18 April 2021 . Retrieved 17 April 2021 . ^ Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature . 582 (7813): 530–533. Bibcode : 2020Natur.582..530I . doi : 10.1038/s41586-020-2343-4 . PMID 32494009 . S2CID 219281856 . ^ Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar" . Latin American Antiquity . 28 (1): 88–104. doi : 10.1017/laq.2016.4 . ISSN 1045-6635 . S2CID 164417025 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida" . Proceedings of the Seminar for Arabian Studies . 46 : 25–40. ISSN 0308-8421 . JSTOR 45163415 . Archived from the original on 28 April 2022 . Retrieved 30 July 2022 . ^ Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration . 21 (1): 25–86. doi : 10.1080/01900699808525297 . ISSN 0190-0692 . ^ Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age" . Journal of the American Oriental Society . 96 (1): 15–26. doi : 10.2307/599886 . ISSN 0003-0279 . JSTOR 599886 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty" . Architectural History . 63 : 1–36. doi : 10.1017/arh.2020.1 . ISSN 0066-622X . S2CID 229716130 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question" . Climate . 6 (4): 90. Bibcode : 2018Clim....6...90M . doi : 10.3390/cli6040090 . ^ Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World . New York: Oxford University Press. p. 72. ISBN 978-0-19-532819-6 . Retrieved 30 July 2022 . ^ Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies . International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi : 10.1007/978-3-319-24774-8_2 . ISBN 978-3-319-24774-8 . ^ Vidal-Nanquet P (1987). The Harper Atlas of World History . Harper & Row Publishers. p. 76. ^ Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land . Simon and Schuster. ISBN 978-1-84983-770-5 . ^ Adam King (2002). "Mississippian Period: Overview" . New Georgia Encyclopedia . Archived from the original on 19 August 2009 . Retrieved 15 November 2009 . ^ Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism . Cambridge University Press. p. 2. ISBN 0-521-31896-3 . ^ May T (2013). The Mongol Conquests in World History . Reaktion Books. p. 7. ISBN 978-1-86189-971-2 . ^ Canós-Donnay S (25 February 2019). "The Empire of Mali" . Oxford Research Encyclopedia of African History . Oxford University Press. doi : 10.1093/acrefore/9780190277734.013.266 . ISBN 978-0-19-027773-4 . Archived from the original on 20 October 2021 . Retrieved 7 May 2021 . ^ Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity" . Asian Perspectives . 37 (2): 135–164. ^ Kafadar C (1 January 1994). "Ottomans and Europe" . In Brady T, Oberman T, Tracy JD (eds.). Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation . Brill. pp. 589–635. doi : 10.1163/9789004391659_019 . ISBN 978-90-04-39165-9 . Archived from the original on 2 May 2022 . Retrieved 17 April 2021 . ^ Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan" . Oxford Research Encyclopedia of Asian History . Oxford University Press. doi : 10.1093/acrefore/9780190277727.013.72 . ISBN 978-0-19-027772-7 . Archived from the original on 12 August 2021 . Retrieved 7 May 2021 . ^ Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing" . Pacific Affairs . 83 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526–1857)" . Al-Ta Lim Journal . 23 (2): 128–138. doi : 10.15548/jt.v23i2.228 . ISSN 2355-7893 . Archived from the original on 7 April 2022 . Retrieved 30 July 2022 . ^ Kirkpatrick R (2002). The European Renaissance, 1400–1600 . Routledge. p. 1. ISBN 978-1-317-88646-4 . OCLC 893909816 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Arnold D (2002). The Age of Discovery, 1400–1600 (Second ed.). Routledge. pp. xi. ISBN 978-1-136-47968-7 . OCLC 859536800 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics" . Theoretical Inquiries in Law . 11 (1). doi : 10.2202/1565-3404.1239 . ISSN 1565-3404 . S2CID 56216309 . Archived from the original on 26 August 2021 . Retrieved 30 July 2022 . ^ Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews . 20 (1–3): 277–299. Bibcode : 2001QSRv...20..277J . doi : 10.1016/S0277-3791(00)00116-5 . ^ Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature" . The Journal of African History . 30 (3): 365–394. doi : 10.1017/S0021853700024439 . ISSN 0021-8537 . JSTOR 182914 . S2CID 161321949 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide . London: Palgrave Macmillan UK. pp. 273–295. doi : 10.1057/9780230297784_11 . ISBN 978-0-230-29778-4 . ^ Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour . 38 (3–4): 157–158. doi : 10.1016/j.endeavour.2014.10.001 . PMID 25457642 . ^ "Greatest Engineering Achievements of the 20th Century" . National Academy of Engineering . Archived from the original on 6 April 2015 . Retrieved 7 April 2015 . ^ Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776 . New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0 . OCLC 299054528 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815" . Journal of Global History . 1 (1): 123–149. doi : 10.1017/S1740022806000076 . ISSN 1740-0228 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Zimmerman AF (November 1931). "Spain and Its Colonies, 1808–1820" . The Hispanic American Historical Review . 11 (4): 439–463. doi : 10.2307/2506251 . JSTOR 2506251 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ David S (2011). "British History in depth: Slavery and the 'Scramble for Africa' " . BBC . Archived from the original on 24 March 2022 . Retrieved 5 May 2021 . ^ Raudzens G (2004). "The Australian Frontier Wars, 1788–1838 (review)" . The Journal of Military History . 68 (3): 957–959. doi : 10.1353/jmh.2004.0138 . ISSN 1543-7795 . S2CID 162259092 . ^ Clark CM (2012). "Polarization of Europe, 1887–1907". The sleepwalkers : how Europe went to war in 1914 . London: Allen Lane. ISBN 978-0-7139-9942-6 . OCLC 794136314 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Robert Dahl (1989). Democracy and Its Critics . Yale UP. pp. 239–240 . ISBN 0-300-15355-4 . ^ McDougall WA (May 1985). "Sputnik, the space race, and the Cold War" . Bulletin of the Atomic Scientists . 41 (5): 20–25. Bibcode : 1985BuAtS..41e..20M . doi : 10.1080/00963402.1985.11455962 . ISSN 0096-3402 . ^ Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?" . Journal of Peace Research . 30 (2): 163–179. doi : 10.1177/0022343393030002004 . ISSN 0022-3433 . S2CID 5482851 . Archived from the original on 21 February 2022 . Retrieved 30 July 2022 . ^ Sachs JD (April 2017). "Globalization – In the Name of Which Freedom?" . Humanistic Management Journal . 1 (2): 237–252. doi : 10.1007/s41463-017-0019-5 . ISSN 2366-603X . S2CID 133030709 . ^ "World" . The World Factbook . CIA . 17 May 2016. Archived from the original on 26 January 2021 . Retrieved 2 October 2016 . ^ "World Population Prospects: The 2017 Revision" (PDF) . United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17. Archived (PDF) from the original on 26 June 2019 . Retrieved 30 July 2022 . ^ "The World's Cities in 2018" (PDF) . United Nations . Archived (PDF) from the original on 1 November 2018. ^ Rector RK (2016). The Early River Valley Civilizations (First ed.). New York: Rosen Publishing. p. 10. ISBN 978-1-4994-6329-3 . OCLC 953735302 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ "How People Modify the Environment" (PDF) . Westerville City School District . Archived (PDF) from the original on 25 February 2021 . Retrieved 13 March 2019 . ^ "Natural disasters and the urban poor" (PDF) . World Bank . October 2003. Archived (PDF) from the original on 9 August 2017. ^ Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities . [London]: Routledge. pp. x. ISBN 978-1-135-01559-6 . OCLC 889953315 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Piantadosi CA (2003). The biology of human survival : life and death in extreme environments . Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5 . OCLC 70215878 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Toups, M.A.; Kitchen, A.; Light, J.E.; Reed, D.L. (2011). "Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa" . Molecular Biology and Evolution . 28 (1): 29–32. doi : 10.1093/molbev/msq234 . PMC 3002236 . PMID 20823373 . ^ O'Neil D. "Human Biological Adaptability; Overview" . Palomar College. Archived from the original on 6 March 2013 . Retrieved 6 January 2013 . ^ "Population distribution and density" . BBC. Archived from the original on 23 June 2017 . Retrieved 26 June 2017 . ^ Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management . 30 (4): 492–507. doi : 10.1007/s00267-002-2737-0 . hdl : 10072/6758 . PMID 12481916 . S2CID 25834286 . ^ Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica" . Vanderbilt Journal of Transnational Law . 23 : 819. Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ "Mission to Mars: Mars Science Laboratory Curiosity Rover" . Jet Propulsion Laboratory. Archived from the original on 18 August 2015 . Retrieved 26 August 2015 . ^ "Touchdown! Rosetta's Philae probe lands on comet" . European Space Agency. 12 November 2014. Archived from the original on 22 August 2015 . Retrieved 26 August 2015 . ^ "NEAR-Shoemaker" . NASA . Archived from the original on 26 August 2015 . Retrieved 26 August 2015 . ^ Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station" . JSC Features . Johnson Space Center . Archived from the original on 16 February 2012 . Retrieved 13 February 2012 . ^ Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth" . Proceedings of the National Academy of Sciences of the United States of America . 115 (25): 6506–6511. Bibcode : 2018PNAS..115.6506B . doi : 10.1073/pnas.1711842115 . PMC 6016768 . PMID 29784790 . ^ Tellier LN (2009). Urban world history: an economic and geographical perspective . Presses de l'Université du Québec. p. 26. ISBN 978-2-7605-1588-8 . Retrieved 30 July 2022 . ^ Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, CA: Dickenson Pub. Co. ISBN 978-0-8221-0166-6 . ^ Harl KW (1998). "Population estimates of the Roman Empire" . Tulane.edu. Archived from the original on 7 May 2016 . Retrieved 8 December 2012 . ^ Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis" . International Journal of Hygiene and Environmental Health . 207 (2): 165–178. doi : 10.1078/1438-4639-00259 . PMC 7128933 . PMID 15031959 . ^ "World's population reaches six billion" . BBC News . 5 August 1999. Archived from the original on 15 April 2008 . Retrieved 5 February 2008 . ^ United Nations. "World population to reach 8 billion on 15 November 2022" . United Nations . Archived from the original on 20 January 2023 . Retrieved 27 October 2022 . ^ "Eight billion people, SARS-CoV-2 ancestor and illegal fishing" . Nature . 611 (641): 641. 23 November 2022. Bibcode : 2022Natur.611..641. . doi : 10.1038/d41586-022-03792-4 . S2CID 253764233 . Archived from the original on 26 January 2023 . Retrieved 26 January 2023 . ^ "World Population to Hit Milestone With Birth of 7 Billionth Person" . PBS NewsHour . 27 October 2011. Archived from the original on 24 September 2017 . Retrieved 11 February 2018 . ^ "68% of the world population projected to live in urban areas by 2050, says UN" . United Nations Department of Economic and Social Affairs (DESA) . 16 May 2018. Archived from the original on 10 March 2021 . Retrieved 18 April 2021 . ^ Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF) . U.S. Department of Justice , Bureau of Justice Statistics. Archived (PDF) from the original on 24 February 2013 . Retrieved 1 October 2006 . ^ Roopnarine PD (March 2014). "Humans are apex predators" . Proceedings of the National Academy of Sciences of the United States of America . 111 (9): E796. Bibcode : 2014PNAS..111E.796R . doi : 10.1073/pnas.1323645111 . PMC 3948303 . PMID 24497513 . ^ Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature" . Science . AAAS . Archived from the original on 26 October 2021 . Retrieved 9 May 2021 . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use – principally agriculture – that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.) ^ Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions" . Proceedings of the National Academy of Sciences of the United States of America . 103 (29): 10941–10946. Bibcode : 2006PNAS..10310941P . doi : 10.1073/pnas.0604181103 . PMC 1544153 . PMID 16829570 . ^ Collins D (1976). The Human Revolution: From Ape to Artist . Phaidon. p. 208 . ISBN 978-0-7148-1676-0 . ^ Weisberger, Mindy (March 23, 2024). "Why don't humans have tails? Scientists find answers in an unlikely place" . CNN . Archived from the original on March 24, 2024 . Retrieved March 24, 2024 . ^ Marks JM (2001). Human Biodiversity: Genes, Race, and History . Transaction Publishers. p. 16. ISBN 978-0-202-36656-2 . ^ Gea, J (2008). "The Evolution of the Human Species: A Long Journey for the Respiratory System". Archivos de Bronconeumología ((English Edition)) . 44 (5): 263–270. doi : 10.1016/S1579-2129(08)60042-7 . ^ O'Neil D. "Humans" . Primates . Palomar College. Archived from the original on 11 January 2013 . Retrieved 6 January 2013 . ^ "How to be Human: The reason we are so scarily hairy" . New Scientist . 2017. Archived from the original on 25 February 2021 . Retrieved 29 April 2020 . ^ Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . ^ Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White" . Evolution: Library . PBS. Archived from the original on 16 February 2013 . Retrieved 6 January 2013 . ^ Roser M, Appel C, Ritchie H (8 October 2013). "Human Height" . Our World in Data . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ "Senior Citizens Do Shrink – Just One of the Body Changes of Aging" . News . Senior Journal. Archived from the original on 19 February 2013 . Retrieved 6 January 2013 . ^ Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology . 136 (1): 71–84. doi : 10.1016/S1095-6433(02)00294-5 . PMID 14527631 . ^ "Human weight" . Articleworld.org. Archived from the original on 8 December 2011 . Retrieved 10 December 2011 . ^ Schlessingerman A (2003). "Mass Of An Adult" . The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018 . Retrieved 31 December 2017 . ^ Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology) . Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1 . Retrieved 5 April 2009 . ^ Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care" . British Journal of Anaesthesia . 85 (1): 91–108. doi : 10.1093/bja/85.1.91 . PMID 10927998 . ^ Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology . 93 (1): 1–16. doi : 10.1086/696721 . ISSN 0033-5770 . S2CID 90757192 . ^ Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance" . The New York Times . Archived from the original on 5 November 2015. ^ John B. "What is the role of sweating glands in balancing body temperature when running a marathon?" . Livestrong.com. Archived from the original on 31 January 2013 . Retrieved 6 January 2013 . ^ Shave, R. E.; Lieberman, D. E.; Drane, A. L.; et al. (2019). "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart" . PNAS . 116 (40): 19905–19910. Bibcode : 2019PNAS..11619905S . doi : 10.1073/pnas.1906902116 . PMC 6778238 . PMID 31527253 . ^ Ríos, L; Sleeper, M. M.; Danforth, M. D.; et al. (2023). "The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution" . Scientific Reports . 13 (6841): 6841. Bibcode : 2023NatSR..13.6841R . doi : 10.1038/s41598-023-33675-1 . hdl : 10261/309357 . PMC 10133235 . PMID 37100851 . ^ Therman E (1980). Human Chromosomes: Structure, Behavior, Effects . Springer US . pp. 112–124. doi : 10.1007/978-1-4684-0107-3 . ISBN 978-1-4684-0109-7 . S2CID 36686283 . ^ Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex" . Journal of Medical Genetics . 3 (2): 117–123. doi : 10.1136/jmg.3.2.117 . PMC 1012913 . PMID 6007033 . ^ Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics . 61 (3): 216–228. doi : 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S . PMID 8741866 . ^ Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics . 53 (1): 27–34. doi : 10.1038/s41588-020-00755-1 . PMID 33414551 . S2CID 230986741 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . Between any two humans, the amount of genetic variation – biochemical individuality – is about 0.1%. ^ Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human" . PLOS Biology . 5 (10): e254. doi : 10.1371/journal.pbio.0050254 . PMC 1964779 . PMID 17803354 . ^ Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research" . American Journal of Human Genetics . 77 (4): 519–532. doi : 10.1086/491747 . PMC 1275602 . PMID 16175499 . ^ "Chimps show much greater genetic diversity than humans" . Media . University of Oxford. Archived from the original on 18 December 2013 . Retrieved 13 December 2013 . ^ Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography" . Proceedings of the National Academy of Sciences of the United States of America . 95 (4): 1961–1967. Bibcode : 1998PNAS...95.1961H . doi : 10.1073/pnas.95.4.1961 . PMC 19224 . PMID 9465125 . ^ Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans" . Proceedings of the National Academy of Sciences of the United States of America . 94 (7): 3100–3103. Bibcode : 1997PNAS...94.3100J . doi : 10.1073/pnas.94.7.3100 . PMC 20328 . PMID 9096352 . ^ Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story" . The New York Times . Archived from the original on 14 January 2012 . Retrieved 13 February 2012 . ^ Pennisi E (February 2001). "The human genome". Science . 291 (5507): 1177–1180. doi : 10.1126/science.291.5507.1177 . PMID 11233420 . S2CID 38355565 . ^ Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature . 590 (7845): 220–221. Bibcode : 2021Natur.590..220R . doi : 10.1038/d41586-021-00237-2 . PMID 33568827 . S2CID 231882262 . ^ Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations" . Nature . 467 (7311): 52–58. Bibcode : 2010Natur.467...52T . doi : 10.1038/nature09298 . PMC 3173859 . PMID 20811451 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private , common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture. ^ Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes" . Genome Biology . 11 (5): 206. doi : 10.1186/gb-2010-11-5-206 . PMC 2898077 . PMID 20441615 . ^ Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature . 325 (6099): 31–36. Bibcode : 1987Natur.325...31C . doi : 10.1038/325031a0 . PMID 3025745 . S2CID 4285418 . ^ Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock" . American Journal of Human Genetics . 84 (6): 740–759. doi : 10.1016/j.ajhg.2009.05.001 . PMC 2694979 . PMID 19500773 . ^ "University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history" . 20 August 2017. Archived from the original on 20 August 2017. ^ Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females" . Science . 341 (6145): 562–565. Bibcode : 2013Sci...341..562P . doi : 10.1126/science.1237619 . PMC 4032117 . PMID 23908239 . ^ Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set . John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1 . ^ Jukic AM, Baird DD, Weinberg CR , McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation" . Human Reproduction . 28 (10): 2848–2855. doi : 10.1093/humrep/det297 . PMC 3777570 . PMID 23922246 . ^ Klossner NJ (2005). Introductory Maternity Nursing . Lippincott Williams & Wilkins. p. 103. ISBN 978-0-7817-6237-3 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . The fetal stage is from the beginning of the 9th week after fertilization and continues until birth ^ World Health Organization (November 2014). "Preterm birth Fact sheet N°363" . who.int . Archived from the original on 7 March 2015 . Retrieved 6 March 2015 . ^ Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application" . American Journal of Obstetrics and Gynecology . 218 (2S): S619–S629. doi : 10.1016/j.ajog.2017.12.010 . PMID 29422204 . S2CID 46810955 . ^ "What is the average baby length? Growth chart by month" . www.medicalnewstoday.com . 18 March 2019. Archived from the original on 27 January 2021 . Retrieved 18 April 2021 . ^ Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal . 5 (2): 113–122. PMID 15024783 . ^ Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology . 35 (S15): 89–124. doi : 10.1002/ajpa.1330350605 . ISSN 1096-8644 . ^ Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma" . American Journal of Obstetrics and Gynecology . 222 (1): 3–16. doi : 10.1016/j.ajog.2019.06.043 . PMC 9069416 . PMID 31251927 . S2CID 195761874 . ^ Barras C (22 December 2016). "The real reasons why childbirth is so painful and dangerous". BBC. ^ Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?" . Newsweek . Archived from the original on 28 June 2007. A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa , compared to 1 in 2,800 in developed countries . ^ Rush D (July 2000). "Nutrition and maternal mortality in the developing world" . The American Journal of Clinical Nutrition . 72 (1 Suppl): 212S–240S. doi : 10.1093/ajcn/72.1.212S . PMID 10871588 . ^ Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour . Oxford University Press. p. 7. ISBN 978-0-19-958696-7 . Retrieved 30 July 2022 . ^ Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning . p. 296. ISBN 978-0-495-60037-4 . Archived from the original on 3 October 2023 . Retrieved 30 July 2022 . ^ Schuiling KD, Likis FE (2016). Women's Gynecologic Health . Jones & Bartlett Learning . p. 22. ISBN 978-1-284-12501-6 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13. ^ Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy . SAGE Publications . pp. 18–19. ISBN 978-1-4833-6475-9 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average). ^ Mintz S (1993). "Life stages". Encyclopedia of American Social History . 3 : 7–33. ^ Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?" . Indian Journal of Endocrinology and Metabolism . 18 (Suppl 1): S53-62. doi : 10.4103/2230-8210.145075 . PMC 4266869 . PMID 25538878 . ^ Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?" . Biology of Reproduction . 79 (3): 398–406. doi : 10.1095/biolreprod.108.068536 . PMC 2553520 . PMID 18495681 . ^ Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality . New York: Basic Books. pp. 167–170. ISBN 978-0-465-03127-6 . ^ Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology . 10 (2): 43–57. doi : 10.1002/evan.1013 . S2CID 1665503 . ^ Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth" . USC Trojan Family Magazine . Archived from the original on 13 December 2010 . Retrieved 7 December 2010 . ^ Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex" . Society of Actuaries. Archived from the original on 1 July 2013. ^ "Life expectancy at birth, female (years)" . World Bank . 2018. Archived from the original on 24 January 2021 . Retrieved 13 October 2020 . ^ "Life expectancy at birth, male (years)" . World Bank . 2018. Archived from the original on 24 February 2021 . Retrieved 13 October 2020 . ^ Conceição P, et al. (2019). Human Development Report (PDF) . United Nations Development Programme. ISBN 978-92-1-126439-5 . Archived (PDF) from the original on 20 March 2021 . Retrieved 30 July 2022 . ^ "Human Development Report 2019" (PDF) . United Nations Development Programme . Archived from the original (PDF) on 22 April 2022 . Retrieved 30 July 2022 . ^ "The World Factbook" . U.S. Central Intelligence Agency. Archived from the original on 12 September 2009 . Retrieved 2 April 2005 . ^ "Chapter 1: Setting the Scene" (PDF) . UNFPA. 2012. Archived from the original (PDF) on 12 June 2013 . Retrieved 11 January 2013 . ^ Haenel H (1989). "Phylogenesis and nutrition". Die Nahrung . 33 (9): 867–887. PMID 2697806 . ^ Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable . pp. 264–265. Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods. ^ American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association . 103 (6): 748–765. doi : 10.1053/jada.2003.50142 . PMID 12778049 . ^ Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet" . American Journal of Physical Anthropology . 162 (S63): 84–109. doi : 10.1002/ajpa.23148 . PMID 28105723 . ^ Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century" . The American Journal of Clinical Nutrition . 81 (2): 341–354. doi : 10.1093/ajcn.81.2.341 . PMID 15699220 . ^ Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context" . The Proceedings of the Nutrition Society . 61 (4): 517–526. doi : 10.1079/PNS2002180 . PMID 12691181 . ^ John Carey (2023). "Unearthing the origins of agriculture" . Proceedings of the National Academy of Sciences . 120 (15): e2304407120. Bibcode : 2023PNAS..12004407C . doi : 10.1073/pnas.2304407120 . PMC 10104519 . PMID 37018195 . ^ Ayelet Shavit; Gonen Sharon (2023). "Can models of evolutionary transition clarify the debates over the Neolithic Revolution?" . Philosophical Transactions of the Royal Society B . 378 (1872). doi : 10.1098/rstb.2021.0413 . PMC 9869441 . PMID 36688395 . } ^ Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences" . The American Journal of Clinical Nutrition . 90 (3): 707S–711S. doi : 10.3945/ajcn.2009.27462B . PMID 19656837 . ^ Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology . 69 (5): 605–628. PMID 9299882 . ^ Gibbons A. "The Evolution of Diet" . National Geographic . Archived from the original on 18 August 2014 . Retrieved 18 April 2021 . ^ Ritchie H, Roser M (20 August 2017). "Diet Compositions" . Our World in Data . Archived from the original on 25 August 2021 . Retrieved 30 July 2022 . ^ Lieberson AD (2004). "How Long Can a Person Survive without Food?" . Scientific American . Archived from the original on 14 February 2019 . Retrieved 18 April 2021 . ^ Spector D (9 March 2018). "Here's how many days a person can survive without water" . Business Insider Australia . Archived from the original on 26 June 2014 . Retrieved 18 April 2021 . ^ Holmes J. "Losing 25,000 to Hunger Every Day" . United Nations . Archived from the original on 27 May 2020 . Retrieved 18 April 2021 . ^ Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic" . NPR . Archived from the original on 28 June 2021 . Retrieved 18 April 2021 . ^ Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet . 349 (9063): 1436–1442. doi : 10.1016/S0140-6736(96)07495-8 . PMID 9164317 . S2CID 2569153 . ^ Haslam DW, James WP (October 2005). "Obesity". Lancet . 366 (9492): 1197–1209. doi : 10.1016/S0140-6736(05)67483-1 . PMID 16198769 . S2CID 208791491 . ^ Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine . 30 (3): 415–444, vii. doi : 10.1016/j.ccm.2009.05.001 . PMID 19700042 . ^ de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology . 2 (1): 45–55. doi : 10.1016/j.ehb.2003.11.001 . PMID 15463992 . ^ O'Neil D. "Adapting to Climate Extremes" . Human Biological Adaptability . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status" . PLOS Genetics . 13 (9): e1006977. doi : 10.1371/journal.pgen.1006977 . PMC 5600404 . PMID 28873402 . ^ Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics . 35 (4): 311–313. doi : 10.1038/ng1263 . PMID 14634648 . S2CID 20415396 . ^ Hedrick PW (October 2011). "Population genetics of malaria resistance in humans" . Heredity . 107 (4): 283–304. doi : 10.1038/hdy.2011.16 . PMC 3182497 . PMID 21427751 . ^ Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria" . British Journal of Haematology . 141 (3): 276–286. doi : 10.1111/j.1365-2141.2008.07085.x . PMID 18410566 . S2CID 28191911 . ^ Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea" . Frontiers in Ecology and Evolution . 5 . doi : 10.3389/fevo.2017.00025 . hdl : 11858/00-001M-0000-002C-DD87-4 . ISSN 2296-701X . S2CID 34882477 . ^ Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads" . Cell . 173 (3): 569–580.e15. doi : 10.1016/j.cell.2018.03.054 . PMID 29677510 . ^ Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology . 45 (1): 105–08. doi : 10.1086/381006 . S2CID 224795768 . ^ Roberts D (2011). Fatal Invention . London & New York: The New Press. ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation" . Proceedings of the National Academy of Sciences of the United States of America . 107 (Supplement_2): 8962–8968. Bibcode : 2010PNAS..107.8962J . doi : 10.1073/pnas.0914628107 . PMC 3024016 . PMID 20445093 . ^ Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF) . Journal of Human Evolution . 39 (1): 57–106. doi : 10.1006/jhev.2000.0403 . PMID 10896812 . Archived from the original (PDF) on 14 January 2012. ^ Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R" . American Journal of Human Genetics . 66 (4): 1351–1361. doi : 10.1086/302863 . PMC 1288200 . PMID 10733465 . ^ Robin A (1991). Biological Perspectives on Human Pigmentation . Cambridge: Cambridge University Press. ^ "The Science Behind the Human Genome Project" . Human Genome Project . US Department of Energy. Archived from the original on 2 January 2013 . Retrieved 6 January 2013 . Almost all (99.9%) nucleotide bases are exactly the same in all people. ^ O'Neil D. "Ethnicity and Race: Overview" . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation" . Nature Genetics . 36 (11 Suppl): S17-20. doi : 10.1038/ng1455 . PMID 15507998 . ^ O'Neil D. "Models of Classification" . Modern Human Variation . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Palmié S (May 2007). "Genomics, divination, 'racecraft' ". American Ethnologist . 34 (2): 205–222. doi : 10.1525/ae.2007.34.2.205 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations. ^ Goodman A. "Interview with Alan Goodman" . Race Power of and Illusion . PBS. Archived from the original on 29 October 2012 . Retrieved 6 January 2013 . ^ Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF) . New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012 . Retrieved 5 September 2013 . ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo ^ O'Neil D. "Overview" . Modern Human Variation . Palomar College. Archived from the original on 5 November 2012 . Retrieved 6 January 2013 . ^ Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" . American Journal of Human Genetics . 66 (3): 979–988. doi : 10.1086/302825 . PMC 1288178 . PMID 10712212 . ^ "New Research Proves Single Origin Of Humans In Africa" . Science Daily . 19 July 2007. Archived from the original on 4 November 2011 . Retrieved 5 September 2011 . ^ Manica A, Amos W, Balloux F , Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation" . Nature . 448 (7151): 346–348. Bibcode : 2007Natur.448..346M . doi : 10.1038/nature05951 . PMC 1978547 . PMID 17637668 . ^ Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals" . Cell . 180 (4): 677–687.e16. doi : 10.1016/j.cell.2020.01.012 . PMID 32004458 . S2CID 210955842 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations. ^ Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations" . Science Advances . 6 (7): eaax5097. Bibcode : 2020SciA....6.5097D . doi : 10.1126/sciadv.aax5097 . PMC 7015685 . PMID 32095519 . Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. ^ Pierce BA (2012). Genetics: A Conceptual Approach . Macmillan. p. 75. ISBN 978-1-4292-3252-4 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology . Cambridge University Press. p. 74. ISBN 978-0-521-87948-4 . Retrieved 30 July 2022 . ^ Fusco G, Minelli A (10 October 2019). The Biology of Reproduction . Cambridge University Press. p. 304. ISBN 978-1-108-49985-9 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution . 47 (4): 253–266. doi : 10.1016/j.jhevol.2004.07.004 . PMID 15454336 . ^ Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960–2002" (PDF) . Advance Data (347): 1–17. PMID 15544194 . Archived from the original (PDF) on 23 February 2011. ^ Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology . 66 (3): 254–262. doi : 10.1007/BF00235103 . hdl : 11375/22586 . PMID 8477683 . S2CID 206772211 . ^ Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity . Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi : 10.1007/978-3-319-70178-3_2 . ISBN 978-3-319-70177-6 . PMID 29224088 . ^ Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know" . International Journal of Women's Dermatology . 4 (3): 122–130. doi : 10.1016/j.ijwd.2018.03.002 . PMC 6116811 . PMID 30175213 . ^ Easter C. "Sex Linked" . National Human Genome Research Institute . Archived from the original on 14 April 2022 . Retrieved 18 April 2021 . ^ Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior . 27 (4): 283–296. doi : 10.1016/j.evolhumbehav.2005.11.003 . S2CID 32562654 . ^ "Gender, women, and health" . Reports from WHO 2002–2005 . Archived from the original on 25 June 2013. ^ Sax, Leonard (1 August 2002). "How common is lntersex? A response to Anne Fausto-Sterling" . The Journal of Sex Research . 39 (3): 174–178. doi : 10.1080/00224490209552139 . ISSN 0022-4499 . PMID 12476264 . S2CID 33795209 . ^ "3-D Brain Anatomy" . The Secret Life of the Brain . Public Broadcasting Service. Archived from the original on 5 September 2017 . Retrieved 3 April 2005 . ^ Stern P (22 June 2018). "The human prefrontal cortex is special" . Science . 360 (6395): 1311–1312. Bibcode : 2018Sci...360S1311S . doi : 10.1126/science.360.6395.1311-g . ISSN 0036-8075 . S2CID 149581944 . ^ Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?" . Journal of Intelligence . 2 (3): 119–121. doi : 10.3390/jintelligence2030119 . ISSN 2079-3200 . ^ "Humans not smarter than animals, just different, experts say" . phys.org . Archived from the original on 30 January 2021 . Retrieved 24 October 2020 . ^ Robson D. "We've got human intelligence all wrong" . www.bbc.com . Archived from the original on 31 January 2021 . Retrieved 24 October 2020 . ^ Owen J (26 February 2015). "Many Animals – Including Your Dog – May Have Horrible Short-Term Memories" . National Geographic News . Archived from the original on 19 April 2021 . Retrieved 6 September 2020 . ^ Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research" . American Journal of Physical Anthropology . 116 (S33): 3–24. doi : 10.1002/ajpa.20001 . PMC 2238342 . PMID 11786989 . ^ Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?" . ABC News (American) . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self" . New Scientist . Archived from the original on 18 February 2021 . Retrieved 22 April 2020 . ^ Beck J (2019). "Can We Really Know What Animals Are Thinking?" . Snopes . Archived from the original on 31 October 2021 . Retrieved 22 April 2020 . ^ Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies" . Sleep Medicine Reviews . 14 (4): 239–247. doi : 10.1016/j.smrv.2009.08.001 . PMC 2888649 . PMID 19896872 . ^ Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep" " . Science.howstuffworks.com. Archived from the original on 15 May 2012 . Retrieved 11 August 2012 . ^ Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience . 10 (11): 803–813. doi : 10.1038/nrn2716 . PMID 19794431 . S2CID 205505278 . ^ Empson J (2002). Sleep and dreaming (3rd ed.). New York: Palgrave/St. Martin's Press. ^ Lite J (29 July 2010). "How Can You Control Your Dreams?" . Scientific America . Archived from the original on 2 February 2015. ^ Domhoff W (2002). The scientific study of dreams . APA Press. ^ "Consciousness" . Merriam-Webster . Archived from the original on 7 September 2019 . Retrieved 4 June 2012 . ^ van Gulick R (2004). "Consciousness" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019 . Retrieved 30 July 2022 . ^ Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness . Wiley. ISBN 978-0-470-75145-9 . ^ Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy . Oxford University Press. ISBN 978-0-19-926479-7 . ^ Block N (June 1995). "On a confusion about a function of consciousness" . Behavioral and Brain Sciences . 18 (2): 227–247. doi : 10.1017/S0140525X00038474 . S2CID 246244859 . ^ Jaynes J (2000) [1976]. The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF) . Houghton Mifflin. ISBN 0-618-05707-2 . Archived from the original (PDF) on 7 August 2019 . Retrieved 25 October 2020 . ^ Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition . 12 (4): 717–731. doi : 10.1016/s1053-8100(03)00081-3 . PMID 14656513 . S2CID 10241157 . ^ Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness" . Stanford Encyclopedia of Philosophy . Archived from the original on 13 April 2021 . Retrieved 31 August 2014 . ^ Antony MV (2001). "Is consciousness ambiguous?". Journal of Consciousness Studies . 8 : 19–44. ^ "Cognition" . Lexico . Oxford University Press and Dictionary.com . Archived from the original on 8 July 2016 . Retrieved 6 May 2020 . ^ Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality . The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi : 10.1007/978-3-030-03633-1_14 . ISBN 978-3-030-03633-1 . S2CID 189379814 . ^ "American Psychological Association (2013). Glossary of psychological terms" . Apa.org. Archived from the original on 8 July 2014 . Retrieved 13 August 2014 . ^ "Developmental Psychology Studies Human Development Across the Lifespan" . www.apa.org . Archived from the original on 9 July 2014 . Retrieved 28 August 2017 . ^ Burman E (2017). Deconstructing Developmental Psychology . New York: Routledge. ISBN 978-1-138-84695-1 . ^ Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology : 307–314. doi : 10.1016/B0-12-657410-3/00510-9 . ISBN 978-0-12-657410-4 . ^ McLeod S (20 March 2020). "Maslow's Hierarchy of Needs" . Simplypsychology.org . Simply Scholar Limited. Archived from the original on 8 November 2018 . Retrieved 4 April 2020 . Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up. ^ Heckhausen J, Heckhausen H (28 March 2018). "Motivation and Action: Introduction and Overview". Motivation and Action . Introduction and Overview: Springer, Cham. p. 1. doi : 10.1007/978-3-319-65094-4_1 . ISBN 978-3-319-65093-7 . ^ Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews . 26 (2–3): 83–86. doi : 10.1016/s0165-0173(97)00064-7 . PMID 9651488 . S2CID 8504450 . ^ Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions . New York: Oxford University Press. pp. 291–293. ISBN 978-0-19-508944-8 . Emotional processing, but not emotions, can occur unconsciously. ^ Cabanac M (2002). "What is emotion?". Behavioural Processes . 60 (2): 69–83. doi : 10.1016/S0376-6357(02)00078-5 . PMID 12426062 . S2CID 24365776 . Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure) ^ Scirst DL (2011). Psychology Second Edition . New York: Worth Publishers. p. 310 . ISBN 978-1-4292-3719-2 . ^ Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality . 67 (2): 331–371. doi : 10.1111/1467-6494.00058 . PMID 10202807 . ^ Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory" . Frontiers in Psychology . 8 : 1454. doi : 10.3389/fpsyg.2017.01454 . PMC 5573739 . PMID 28883804 . ^ Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology . Oxford University Press. Archived from the original on 29 January 2021 . Retrieved 30 July 2022 . ^ Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals" . Industrial Psychiatry Journal . 24 (1): 54–58. doi : 10.4103/0972-6748.160934 . PMC 4525433 . PMID 26257484 . ^ Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions" . The American Psychologist . 56 (3): 218–226. doi : 10.1037/0003-066X.56.3.218 . PMC 3122271 . PMID 11315248 . ^ Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica . 90 (3): 387–411. doi : 10.11612/resphil.2013.90.3.5 . ^ Haybron DM (13 April 2014). "Happiness and Its Discontents" . The Opinion Pages . The New York Times. Archived from the original on 12 October 2018 . Retrieved 30 July 2022 . I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life. ^ Graham MC (2014). Facts of Life: ten issues of contentment . Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5 . ^ "Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy" . ScienceDaily . American Psychological Association . 14 August 2017. Archived from the original on 11 November 2020 . Retrieved 25 October 2020 . ^ Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality . Jones & Bartlett Publishers . pp. 4–10. ISBN 978-1-284-08154-1 . Retrieved 21 June 2017 . Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings. ^ Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives . Taylor & Francis . pp. 32–42. ISBN 978-0-7890-2671-2 . ^ Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology . 3 (4): 85–89. doi : 10.1097/01.XHA.0000432482.01760.b0 . S2CID 147235090 . ^ "Sexual orientation, homosexuality and bisexuality" . American Psychological Association . Archived from the original on 8 August 2013 . Retrieved 10 August 2013 . ^ Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science" . Psychological Science in the Public Interest . 17 (2): 45–101. doi : 10.1177/1529100616637616 . PMID 27113562 . ^ LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation . Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6 . Retrieved 30 July 2022 . ^ Balthazart J (2012). The Biology of Homosexuality . Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0 . Retrieved 30 July 2022 . ^ Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York: Basic Books. ISBN 978-0-465-00802-5 . ^ Fromm E (2000). The art of loving . New York: Harper Perennial. ISBN 978-0-06-095828-2 . ^ "Love, Actually: The science behind lust, attraction, and companionship" . Science in the News . 14 February 2017. Archived from the original on 28 October 2020 . Retrieved 25 October 2020 . ^ "What are the top 200 most spoken languages?" . Ethnologue: Languages of the World . 2020. Archived from the original on 12 January 2013 . Retrieved 30 July 2022 . ^ World . The World Factbook (Report). Central Intelligence Agency . Archived from the original on 26 January 2021 . Retrieved 15 November 2021 . ^ "The Changing Global Religious Landscape" . Pew Research Center. 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 30 July 2022 . ^ Ord T (2020). The Precipice: Existential Risk and the Future of Humanity . New York: Hachette Books. ISBN 978-0-316-48489-3 . Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence... ^ Goldman JG (2012). "Pay attention… time for lessons at animal school" . bbc.com . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding" . Science Advances . 4 (11): eaar8334. Bibcode : 2018SciA....4.8334W . doi : 10.1126/sciadv.aar8334 . PMC 6248967 . PMID 30474053 . ^ Johnson-Frey SH (July 2003). "What's so special about human tool use?" . Neuron . 39 (2): 201–204. doi : 10.1016/S0896-6273(03)00424-0 . PMID 12873378 . S2CID 18437970 . ^ Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology . 19 (1): 27–33. doi : 10.1016/j.conb.2009.02.003 . PMID 19328675 . S2CID 18277620 . In short, the evidence to date that animals have an understanding of folk physics is at best mixed. ^ Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To" . National Geographic News . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education" . Procedia - Social and Behavioral Sciences . The Proceedings of 6th World Conference on educational Sciences. 191 : 2565–2567. doi : 10.1016/j.sbspro.2015.04.690 . ISSN 1877-0428 . ^ McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species" . The Guardian . Archived from the original on 5 February 2021 . Retrieved 22 April 2020 . ^ Nicholls H (29 June 2015). "Babblers speak to the origin of language" . The Guardian . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Dasgupta S (2015). "Can any animals talk and use language like humans?" . bbc.com . Archived from the original on 2 May 2020 . Retrieved 22 April 2020 . Most animals are not vocal learners. ^ Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?" . Royal Society. Archived from the original on 18 January 2021 . Retrieved 24 October 2020 . ^ Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?" . BMC Biology . 15 (1): 64. doi : 10.1186/s12915-017-0405-3 . PMC 5525259 . PMID 28738867 . ^ Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist . 208 (2789): ii–iii. Bibcode : 2010NewSc.208D...2F . doi : 10.1016/S0262-4079(10)62961-2 . ISSN 0262-4079 . ^ Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments . London: Palgrave Macmillan UK. pp. 229–255. doi : 10.1057/978-1-137-58746-6_7 . ISBN 978-1-137-58746-6 . ^ "Culture | United Nations For Indigenous Peoples" . www.un.org . 5 June 2015. Archived from the original on 26 November 2020 . Retrieved 24 October 2020 . ^ Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World . New York: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1 . ^ Mavrody S (2013). Visual Art Forms: Traditional to Digital . Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9 . Retrieved 30 July 2022 . ^ "Types of Literary Arts and Their Understanding – bookfestivalscotland.com" . Bookfestival Scotland . 2020. Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ "Bachelor of Performing Arts" (PDF) . University of Otago . Archived (PDF) from the original on 14 December 2021 . Retrieved 30 July 2022 . ^ Brown S (24 October 2018). "Toward a Unification of the Arts" . Frontiers in Psychology . 9 : 1938. doi : 10.3389/fpsyg.2018.01938 . ISSN 1664-1078 . PMC 6207603 . PMID 30405470 . ^ "Culinary arts – How cooking can be an art" . Northern Contemporary Art . 21 October 2019. Archived from the original on 11 May 2021 . Retrieved 5 May 2021 . ^ Smuts A (1 January 2005). "Are Video Games Art?" . Contemporary Aesthetics (Journal Archive) . 3 (1). Archived from the original on 29 May 2022 . Retrieved 30 July 2022 . ^ Cameron IA, Pimlott N (September 2015). "Art of medicine" . Canadian Family Physician . 61 (9): 739–740. PMC 4569099 . PMID 26371092 . ^ Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy . 25 (4): 458–470. doi : 10.1080/10286632.2017.1311328 . ISSN 1028-6632 . S2CID 151443044 . ^ Morriss-Kay GM (February 2010). "The evolution of human artistic creativity" . Journal of Anatomy . 216 (2): 158–176. doi : 10.1111/j.1469-7580.2009.01160.x . PMC 2815939 . PMID 19900185 . ^ Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature . 518 (7538): 228–231. Bibcode : 2015Natur.518..228J . doi : 10.1038/nature13962 . PMID 25470048 . S2CID 4461751 . ^ St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave" . The New York Times . Archived from the original on 14 April 2020 . Retrieved 20 September 2018 . ^ Radford T (16 April 2004). "World's oldest jewellery found in cave" . The Guardian . ISSN 0261-3077 . Archived from the original on 12 February 2021 . Retrieved 23 September 2020 . ^ Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches . Amsterdam: Valiz. pp. 241–263. ^ Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia . 92 (92): 147–177. doi : 10.4436/JASS.92008 (inactive 2024-03-20). PMID 25020016 . {{ cite journal }} : CS1 maint: DOI inactive as of March 2024 ( link ) ^ Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness" (PDF) . NeuroImage . 103 : 55–64. doi : 10.1016/j.neuroimage.2014.09.009 . PMID 25224999 . S2CID 4727529 . ^ Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences . 1337 (1): 140–146. Bibcode : 2015NYASA1337..140K . doi : 10.1111/nyas.12632 . PMID 25773628 . S2CID 206224849 . ^ Chow D (22 March 2010). "Why Do Humans Dance?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 21 September 2020 . ^ Krakauer J (26 September 2008). "Why do we like to dance – And move to the beat?" . Scientific American . Archived from the original on 28 February 2021 . Retrieved 21 September 2020 . ^ Prior KS (21 June 2013). "How Reading Makes Us More Human" . The Atlantic . Archived from the original on 29 January 2021 . Retrieved 23 September 2020 . ^ Puchner M. "How stories have shaped the world" . www.bbc.com . Archived from the original on 5 January 2021 . Retrieved 23 September 2020 . ^ Dalley, Stephanie , ed. (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5 . ^ Hernadi P (2001). "Literature and Evolution" . SubStance . 30 (1/2): 55–71. doi : 10.2307/3685504 . ISSN 0049-2426 . JSTOR 3685504 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run" . The Guardian (U.S. ed.). New York. Archived from the original on 18 June 2022 . Retrieved 30 July 2022 . ^ Clark JD; de Heinzelin J ; Schick KD ; Hart WK; White TD ; WoldeGabriel G; Walter RC; Suwa G ; Asfaw B ; Vrba E ; H.-Selassie Y (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science . 264 (5167): 1907–1910. Bibcode : 1994Sci...264.1907C . doi : 10.1126/science.8009220 . PMID 8009220 . ^ Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use" . livescience.com . Archived from the original on 4 October 2020 . Retrieved 9 October 2020 . ^ Orban GA, Caruana F (2014). "The neural basis of human tool use" . Frontiers in Psychology . 5 : 310. doi : 10.3389/fpsyg.2014.00310 . PMC 3988392 . PMID 24782809 . ^ Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa" . Proceedings of the National Academy of Sciences of the United States of America . 109 (20): E1215-20. doi : 10.1073/pnas.1117620109 . PMC 3356665 . PMID 22474385 . ^ Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1696): 20150164. doi : 10.1098/rstb.2015.0164 . PMC 4874402 . PMID 27216521 . ^ Damiano J (2018). "Neolithic Era Tools: Inventing a New Age" . MagellanTV . Archived from the original on 5 January 2021 . Retrieved 9 October 2020 . ^ Deng Y, Wang P (2011). Ancient Chinese inventions . Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6 . OCLC 671710733 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Schifman J (9 July 2018). "The Entire History of Steel" . Popular Mechanics . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Wilkinson, Freddie (9 January 2020). "Industrial Revolution and Technology" . National Geographic Society . Archived from the original on 30 September 2020 . Retrieved 9 October 2020 . ^ Roser, Max ; Ritchie, Hannah (11 May 2013). "Technological Progress" . Our World in Data . Archived from the original on 10 September 2021 . Retrieved 30 July 2022 . ^ Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel" . The Atlantic . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Idinopulos TA (1998). "What Is Religion?" . CrossCurrents . 48 (3): 366–380. ISSN 0011-1953 . JSTOR 24460821 . Archived from the original on 13 October 2020 . Retrieved 30 July 2022 . ^ Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology . 54 (1): 377–402. doi : 10.1146/annurev.psych.54.101601.145024 . PMID 12171998 . ^ King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?" . The Atlantic . Archived from the original on 20 January 2021 . Retrieved 8 October 2020 . ^ Ball P (2015). "Complex societies evolved without belief in all-powerful deity" . Nature News . doi : 10.1038/nature.2015.17040 . S2CID 183474917 . Archived from the original on 16 May 2021 . Retrieved 30 July 2022 . ^ Culotta E (November 2009). "Origins. On the origin of religion". Science . 326 (5954): 784–787. Bibcode : 2009Sci...326..784C . doi : 10.1126/science.326_784 . PMID 19892955 . ^ Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation" . Evolution and Human Behavior . 32 (1): 41–49. doi : 10.1016/j.evolhumbehav.2010.07.008 . ISSN 1090-5138 . Archived from the original on 15 October 2020 . Retrieved 30 July 2022 . ^ Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA – Journal of Death and Dying . 41 (1): 5–22. doi : 10.2190/Q21C-5VED-GYW6-W091 . ISSN 0030-2228 . S2CID 145686249 . ^ McKay R, Whitehouse H (March 2015). "Religion and morality" . Psychological Bulletin . 141 (2): 447–473. doi : 10.1037/a0038455 . PMC 4345965 . PMID 25528346 . ^ Bernhard Nitsche; Marcus Schmücker, eds. (2023). God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality . De Gruyter . doi : 10.1515/9783110698343 . ISBN 978-3-11-069834-3 . ^ Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique" . Journal of Religion and Health (Submitted manuscript). 47 (2): 134–163. doi : 10.1007/s10943-008-9165-2 . PMC 8823950 . PMID 19105008 . S2CID 25349208 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular" . The Guardian . ISSN 0261-3077 . Archived from the original on 1 March 2021 . Retrieved 8 October 2020 . ^ Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe" . Pew Research Center . Archived from the original on 24 November 2019 . Retrieved 8 October 2020 . ^ "The Changing Global Religious Landscape" . Pew Research Center's Religion & Public Life Project . 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 8 October 2020 . ^ Di Christina, Mariette (September 2018). "A Very Human Story: Why Our Species Is Special" . Scientific American . Archived from the original on 24 November 2020 . Retrieved 27 September 2020 . ^ Andersen H , Hepburn B (2020). "Scientific Method" . In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Lo Presti R (2014). "History of science: The first scientist" . Nature . 512 (7514): 250–251. Bibcode : 2014Natur.512..250L . doi : 10.1038/512250a . ISSN 1476-4687 . S2CID 4394696 . ^ Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn . Springer. p. 1. ISBN 978-3-642-18904-3 . OCLC 883392276 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Needham, J ; Wang Ling (1954). Science and civilisation in China . Cambridge University Press. p. 111. ISBN 0-521-05799-X . OCLC 779676 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6 . OCLC 615209781 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017 . Retrieved 3 July 2017 . ^ Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition . Cambridge University Press. pp. 209–210. ISBN 978-1-107-01116-8 . ^ "Branches of Science" (PDF) . University of Chicago . Archived from the original (PDF) on 23 April 2017 . Retrieved 26 June 2017 . ^ "What is Philosophy?" . Department of Philosophy . Florida State University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ "Philosophy" . Definition, Systems, Fields, Schools, & Biographies . Encyclopedia Britannica. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day" . Philosophy and Phenomenological Research . 7 (3): 461. doi : 10.2307/2102800 . JSTOR 2102800 . Archived from the original on 31 March 2022 . Retrieved 30 July 2022 . ^ Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?" . ieet.org . Archived from the original on 4 March 2021 . Retrieved 8 August 2020 . ^ Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?" . European Journal of Information Systems . 27 (3): 263–277. doi : 10.1080/0960085X.2018.1470776 . hdl : 2086/16128 . ISSN 0960-085X . S2CID 64796132 . ^ Schizzerotto A. "Social Stratification" (PDF) . University of Trento . Archived from the original (PDF) on 20 March 2018 . Retrieved 3 July 2017 . ^ Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution . Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9 . OCLC 1082411117 . ^ "Social Role Theory of Sex Differences and Similarities : A Current Appraisal" . The Developmental Social Psychology of Gender . Psychology Press. 2000. pp. 137–188. doi : 10.4324/9781410605245-12 . ISBN 978-1-4106-0524-5 . Archived from the original on 30 April 2021 . Retrieved 10 June 2022 . ^ Blackstone, Amy (2003). "Gender Roles and Society" . In Miller, Julia R.; Lerner, Richard M.; Schiamberg, Lawrence B. (eds.). Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments . Sociology School Faculty Scholarship. Santa barbara, CA: ABC-CLIO. p. 335. Archived from the original on 16 May 2022 . Retrieved 30 July 2022 . ^ Nadal, Kevin L. (2017). The SAGE Encyclopedia of Psychology and Gender . SAGE Publications. p. 401. ISBN 978-1483384276 . Most cultures currently construct their societies based on the understanding of gender binary – the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization. ^ Herdt, Gilbert (2020). "Third Sexes and Third Genders". Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . Princeton, NJ: Princeton University Press. pp. 21–83. ISBN 978-1-942130-52-9 . Retrieved 30 July 2022 . ^ Trumbach, Randolph (1994). "London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture". In Herdt, Gilbert (ed.). Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . New York: Zone (MIT). pp. 111–136. ISBN 978-0-942299-82-3 . ^ Graham, Sharyn (April–June 2001). "Sulawesi's fifth gender" . Inside Indonesia . Archived from the original on 26 November 2014. ^ Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John ; Nieder, Timo O.; T'Sjoen, Guy (2016). "Non-binary or genderqueer genders" . International Review of Psychiatry . 28 (1): 95–102. doi : 10.3109/09540261.2015.1106446 . hdl : 1854/LU-7279758 . PMID 26753630 . S2CID 29985722 . Archived from the original on 26 June 2019 . Retrieved 9 June 2019 . ^ Ananthaswamy, Anil; Douglas, Kate. "The origins of sexism: How men came to rule 12,000 years ago" . New Scientist . Retrieved 7 March 2023 . ^ "What do we mean by "sex" and "gender"?" . World Health Organization . Archived from the original on 30 January 2017 . Retrieved 26 November 2015 . ^ Alters S, Schiff W (2009). Essential Concepts for Healthy Living . Jones & Bartlett Publishers . p. 143. ISBN 978-0-7637-5641-3 . Retrieved 3 January 2018 . ^ Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy . 21 (3): 416–438. doi : 10.1093/oxrep/gri024 . ^ Dobres, Marcia-Anne (27 November 2020). "Gender in the Earliest Human Societies" . In Meade, Teresa A.; Wiesner-Hanks, Merry E. (eds.). A Companion to Global Gender History (1 ed.). Wiley. pp. 183–204. doi : 10.1002/9781119535812.ch11 . ISBN 978-1-119-53580-5 . S2CID 229399965 . Archived from the original on 10 June 2022 . Retrieved 10 June 2022 . ^ "The Nature of Kinship: Overview" . www2.palomar.edu . Archived from the original on 3 December 2020 . Retrieved 24 October 2020 . ^ Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition" . Proceedings of the National Academy of Sciences of the United States of America . 117 (5): 2378–2384. Bibcode : 2020PNAS..117.2378I . doi : 10.1073/pnas.1917716117 . PMC 7007516 . PMID 31964846 . ^ Chandra, Kanchan (2012). Constructivist theories of ethnic politics . Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7 . OCLC 829678440 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389. In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of 'us' and 'them.' In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population. ^ Blackmore E (22 February 2019). "Race and ethnicity: How are they different?" . Culture . Archived from the original on 22 October 2020 . Retrieved 24 October 2020 . ^ Chandra K (2006). "What is Ethnic Identity and Does It Matter?" . Annual Review of Political Science . 9 (1): 397–424. doi : 10.1146/annurev.polisci.9.062404.170715 . ISSN 1094-2939 . ^ Smith AD (1999). Myths and Memories of the Nation . Oxford University Press. pp. 4–7. ^ Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism . 13 (1): 19–35. doi : 10.1111/j.1469-8129.2007.00271.x . ^ Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism . London: Sage. p. 171. ISBN 978-1-4129-0101-7 . ^ Christian D (2004). Maps of Time . University of California Press. ISBN 978-0-520-24476-4 . ^ Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?" . SAPIENS . Archived from the original on 7 August 2020 . Retrieved 24 October 2020 . ^ Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit" . Proceedings of the National Academy of Sciences of the United States of America . 115 (19): E4532–E4540. Bibcode : 2018PNAS..115E4532Z . doi : 10.1073/pnas.1708960115 . PMC 5948950 . PMID 29674447 . S2CID 4993139 . ^ Melina R (14 February 2011). "What Are the Different Types of Governments?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 24 October 2020 . ^ "Democracy Index 2021: less than half the world lives in a democracy" . The Economist Democracy Index . Economist Intelligence Unit . February 10, 2022. ^ Jeannie Evers (23 December 2012). "international organization" . National Geographic Society . Archived from the original on 27 April 2017 . Retrieved 24 October 2020 . ^ Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization . 58 (1): 1–29. doi : 10.1016/j.jebo.2004.03.009 . ISSN 0167-2681 . ^ Gibbons J (11 August 2015). "Why did Neanderthals go extinct?" . Smithsonian Insider . Archived from the original on 12 November 2020 . Retrieved 11 October 2020 . ^ University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?" . www.newswise.com . Archived from the original on 1 February 2021 . Retrieved 11 October 2020 . ^ Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years" . inews.co.uk . Archived from the original on 23 January 2021 . Retrieved 11 October 2020 . ^ Henriques M. "How spices changed the ancient world" . www.bbc.com . Archived from the original on 25 January 2021 . Retrieved 11 October 2020 . ^ Strauss IE (26 February 2016). "The Myth of the Barter Economy" . The Atlantic . Archived from the original on 15 February 2021 . Retrieved 11 October 2020 . ^ "The History of Money" . www.pbs.org . 26 October 1996. Archived from the original on 29 November 2020 . Retrieved 11 October 2020 . ^ "Why do we need economists and the study of economics?" . Federal Reserve Bank of San Francisco . July 2000. Archived from the original on 12 November 2020 . Retrieved 23 October 2020 . ^ Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong" . New Scientist . Archived from the original on 3 February 2021 . Retrieved 24 October 2020 . ^ Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates" . The Atlantic . Archived from the original on 7 May 2021 . Retrieved 7 May 2021 . ^ Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature . 538 (7624): 233–237. Bibcode : 2016Natur.538..233G . doi : 10.1038/nature19758 . PMID 27680701 . S2CID 4454927 . ^ Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF) . Nature . 538 (7624): 180–181. Bibcode : 2016Natur.538..180P . doi : 10.1038/nature19474 . PMID 27680700 . S2CID 4459560 . Archived (PDF) from the original on 20 May 2022 . Retrieved 30 July 2022 . ^ Ferguson RB (1 September 2018). "War Is Not Part of Human Nature" . Scientific American . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Ferguson N (September–October 2006). "The Next War of the World" . Foreign Affairs . Archived from the original on 25 April 2022 . Retrieved 30 July 2022 . ^ Beauchamp, Zack (June 23, 2015). "600 years of war and peace, in one amazing chart" . Vox . External links Listen to this article ( 1 hour and 16 minutes ) This audio file was created from a revision of this article dated 11 January 2022 ( 2022-01-11 ) , and does not reflect subsequent edits. ( Audio help · More spoken articles ) v t e Human evolution Taxonomy ( Hominins ) Last common ancestors Chimpanzee–human Gorilla–human Orangutan–human Gibbon–human Australopithecines Nakalipithecus Orrorin Sahelanthropus Kenyanthropus Ardipithecus A. kadabba A. ramidus Australopithecus A. afarensis A. africanus A. anamensis A. bahrelghazali A. deyiremeda A. garhi A. sediba Paranthropus P. aethiopicus P. boisei P. robustus Humans and proto-humans ( Homo ) Proto-humans H. gautengensis (?) H. habilis H. naledi H. rudolfensis (?) H. tsaichangensis (?) Homo erectus H. e. erectus H. e. georgicus H. e. lantianensis H. e. nankinensis H. e. pekinensis H. e. soloensis H. e. tautavelensis H. e. yuanmouensis Archaic humans H. antecessor Denisovans H. ergaster (?) H. floresiensis H. heidelbergensis H. longi (?) H. luzonensis H. neanderthalensis H. rhodesiensis (?) Modern humans Homo sapiens H. s. sapiens (archaic homo sapiens, anatomically modern humans) Jebel Irhoud H. s. idaltu Cro-Magnon Manot people Tam Pa Ling Red Deer Cave people Ancestors Homo habilis → Homo ergaster / Homo erectus (→ Homo antecessor ) → Homo heidelbergensis → archaic Homo sapiens → Homo sapiens Models General models Hunting Gathering Endurance running Aquatic ape Sexual selection Self-domestication Specific models Diet Cooking Expensive tissue Shore-based Drugs Drunken monkey Evolutionary models of human drug use Stoned ape theory Behavior Killer ape Cooperative eye Life history Grandmother Patriarch Topics Bipedalism Skeleton Muscles Skin color Hair Thermoregulation Speech Language Intelligence Gender roles Origin of modern humans Recent African origin Multiregional origin Archaic admixture Behavioral modernity Early migrations Recent evolution Timelines Human evolution Human prehistory Human timeline Others Theorists Books Fossils Evolutionary anthropology Paleoanthropology Human evolutionary developmental biology Category Commons Evolutionary biology Portal v t e Extant species of family Hominidae (great apes) Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Hominidae Ponginae Pongo (Orangutans) Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Homininae Gorilla (Gorillas) Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Hominini Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Homo (Humans) Human ( H. sapiens ) Category v t e Apes Extant ape species Homo Human ( H. sapiens ) Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Gorilla Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Orangutan Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Gibbon ( family : Hylobatidae) Study of apes Great ape language Dian Fossey Birutė Galdikas Jane Goodall Chimpanzee genome project Human Genome Project Gladys Kalema-Zikusoka Neanderthal genome project Willie Smits Lone Drøscher Nielsen Ian Redmond Elgin Center Iowa Primate Learning Sanctuary Borneo Orangutan Survival Primate archaeology Legal and social status Personhood Research ban Kinshasa Declaration on Great Apes Great Ape Project Great Apes Survival Partnership International Primate Day Nonhuman Rights Project Related Primate List of individual apes (non-human) Apes in space (non-human) Bigfoot Bushmeat Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor Gibbon–human last common ancestor List of fictional primates (non-human) Great apes Human evolution Monkey Day Mythic humanoids Yeren Yeti Yowie Category Humans at Wikipedia's sister projects : Definitions from Wiktionary Media from Commons Quotations from Wikiquote Texts from Wikisource Taxa from Wikispecies Taxon identifiers Homo sapiens Wikidata : Q15978631 ADW : Homo_sapiens BOLD : 12439 CoL : 6MB3T EoL : 327955 EPPO : HOMXSA GBIF : 2436436 iNaturalist : 43584 IRMNG : 10857762 ITIS : 180092 MDD : 1000718 MSW : 12100795 NBN : NHMSYS0000376773 NCBI : 9606 NZOR: d83185ac-1aa6-4f59-8645-fe8c040857b3 Observation.org : 83981 OBIS : 1455977 Open Tree of Life : 770315 Paleobiology Database : 83088 TSA : 8319 WoRMS : 1455977 ZooBank : 58D31D52-713D-44B4-9FE9-CB2D9249C422 Authority control databases International FAST National France BnF data Germany Israel Czech Republic Korea Other Encyclopedia of Modern Ukraine NARA İslâm Ansiklopedisi Retrieved from " https://en.wikipedia.org/w/index.php?title=Human&oldid=1221314650 " Categories : Hominini Humans Apex predators Mammals described in 1758 Taxa named by Carl Linnaeus Tool-using mammals Cosmopolitan mammals Hidden categories: CS1 maint: DOI inactive as of March 2024 Articles with short description Short description is different from Wikidata Good articles Wikipedia indefinitely semi-protected pages Wikipedia indefinitely move-protected pages Articles with 'species' microformats Articles containing Latin-language text Articles containing Old French (842-ca. 1400)-language text Articles containing French-language text Articles containing potentially dated statements from 2018 All articles containing potentially dated statements Articles with hAudio microformats Spoken articles Pages using Sister project links with wikidata mismatch Pages using Sister project links with default search Taxonbars desynced from Wikidata Taxonbars on possible non-taxon pages Taxonbars with 20–24 taxon IDs Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with GND identifiers Articles with J9U identifiers Articles with NKC identifiers Articles with NLK identifiers Articles with EMU identifiers Articles with NARA identifiers Articles with TDVİA identifiers Articles containing video clips This page was last edited on 29 April 2024, at 05:20 (UTC) . Text is available under the Creative Commons Attribution-ShareAlike License 4.0 ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy . Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. , a non-profit organization. Privacy policy About Wikipedia Disclaimers Contact Wikipedia Code of Conduct Developers Statistics Cookie statement Mobile view
Contents move to sidebar hide (Top) 1 Etymology and definition 2 Evolution 3 History Toggle History subsection 3.1 Prehistory 3.2 Ancient 3.3 Medieval 3.4 Modern 3.5 Contemporary 4 Habitat and population 5 Biology Toggle Biology subsection 5.1 Anatomy and physiology 5.2 Genetics 5.3 Life cycle 5.4 Diet 5.5 Biological variation 6 Psychology Toggle Psychology subsection 6.1 Sleep and dreaming 6.2 Consciousness and thought 6.3 Motivation and emotion 6.4 Sexuality and love 7 Culture Toggle Culture subsection 7.1 Language 7.2 The arts 7.3 Tools and technologies 7.4 Religion and spirituality 7.5 Science and philosophy 8 Society Toggle Society subsection 8.1 Gender 8.2 Kinship 8.3 Ethnicity 8.4 Government and politics 8.5 Trade and economics 8.6 Conflict 9 See also 10 Notes 11 References 12 External links
Contents move to sidebar hide (Top) 1 Etymology and definition 2 Evolution 3 History Toggle History subsection 3.1 Prehistory 3.2 Ancient 3.3 Medieval 3.4 Modern 3.5 Contemporary 4 Habitat and population 5 Biology Toggle Biology subsection 5.1 Anatomy and physiology 5.2 Genetics 5.3 Life cycle 5.4 Diet 5.5 Biological variation 6 Psychology Toggle Psychology subsection 6.1 Sleep and dreaming 6.2 Consciousness and thought 6.3 Motivation and emotion 6.4 Sexuality and love 7 Culture Toggle Culture subsection 7.1 Language 7.2 The arts 7.3 Tools and technologies 7.4 Religion and spirituality 7.5 Science and philosophy 8 Society Toggle Society subsection 8.1 Gender 8.2 Kinship 8.3 Ethnicity 8.4 Government and politics 8.5 Trade and economics 8.6 Conflict 9 See also 10 Notes 11 References 12 External links
Contents move to sidebar hide (Top) 1 Etymology and definition 2 Evolution 3 History Toggle History subsection 3.1 Prehistory 3.2 Ancient 3.3 Medieval 3.4 Modern 3.5 Contemporary 4 Habitat and population 5 Biology Toggle Biology subsection 5.1 Anatomy and physiology 5.2 Genetics 5.3 Life cycle 5.4 Diet 5.5 Biological variation 6 Psychology Toggle Psychology subsection 6.1 Sleep and dreaming 6.2 Consciousness and thought 6.3 Motivation and emotion 6.4 Sexuality and love 7 Culture Toggle Culture subsection 7.1 Language 7.2 The arts 7.3 Tools and technologies 7.4 Religion and spirituality 7.5 Science and philosophy 8 Society Toggle Society subsection 8.1 Gender 8.2 Kinship 8.3 Ethnicity 8.4 Government and politics 8.5 Trade and economics 8.6 Conflict 9 See also 10 Notes 11 References 12 External links
Contents move to sidebar hide (Top) 1 Etymology and definition 2 Evolution 3 History Toggle History subsection 3.1 Prehistory 3.2 Ancient 3.3 Medieval 3.4 Modern 3.5 Contemporary 4 Habitat and population 5 Biology Toggle Biology subsection 5.1 Anatomy and physiology 5.2 Genetics 5.3 Life cycle 5.4 Diet 5.5 Biological variation 6 Psychology Toggle Psychology subsection 6.1 Sleep and dreaming 6.2 Consciousness and thought 6.3 Motivation and emotion 6.4 Sexuality and love 7 Culture Toggle Culture subsection 7.1 Language 7.2 The arts 7.3 Tools and technologies 7.4 Religion and spirituality 7.5 Science and philosophy 8 Society Toggle Society subsection 8.1 Gender 8.2 Kinship 8.3 Ethnicity 8.4 Government and politics 8.5 Trade and economics 8.6 Conflict 9 See also 10 Notes 11 References 12 External links
Toggle the table of contents Human 213 languages Afrikaans Alemannisch አማርኛ अंगिका العربية Aragonés ܐܪܡܝܐ Armãneashti অসমীয়া Asturianu Atikamekw अवधी Avañe'ẽ Авар Aymar aru Azərbaycanca تۆرکجه Basa Bali বাংলা Banjar 閩南語 / Bân-lâm-gú Basa Banyumasan Башҡортса Беларуская Беларуская (тарашкевіца) भोजपुरी Bikol Central Български Boarisch བོད་ཡིག Bosanski Brezhoneg Буряад Català Чӑвашла Cebuano Čeština ChiShona ChiTumbuka Corsu Cymraeg Dagbanli Dansk الدارجة Davvisámegiella Deutsch डोटेली Eesti Ελληνικά Эрзянь Español Esperanto Euskara فارسی Fiji Hindi Føroyskt Frysk Furlan Gaeilge Gàidhlig Galego ГӀалгӀай 贛語 گیلکی ગુજરાતી 客家語/Hak-kâ-ngî 한국어 Hausa Հայերեն हिन्दी Hrvatski Ido Igbo Ilokano Bahasa Indonesia ᐃᓄᒃᑎᑐᑦ / inuktitut Ирон IsiXhosa IsiZulu Íslenska עברית Jawa ಕನ್ನಡ Kapampangan ქართული कॉशुर / کٲشُر Қазақша Kernowek Kiswahili Коми Kongo Kreyòl ayisyen Kriyòl gwiyannen Kurdî Кыргызча Ladin Лакку ລາວ Latgaļu Latina Latviešu Лезги Lietuvių Ligure Limburgs Lingála Lingua Franca Nova La .lojban. Luganda Magyar मैथिली Македонски Malagasy മലയാളം Malti मराठी მარგალური مصرى مازِرونی Bahasa Melayu ꯃꯤꯇꯩ ꯂꯣꯟ Minangkabau 閩東語 / Mìng-dĕ̤ng-ngṳ̄ Mirandés Мокшень Монгол မြန်မာဘာသာ Nāhuatl Nederlands Nedersaksies नेपाली नेपाल भाषा 日本語 Нохчийн Nordfriisk Norfuk / Pitkern Norsk bokmål Norsk nynorsk Occitan Олык марий ଓଡ଼ିଆ Oʻzbekcha / ўзбекча ਪੰਜਾਬੀ पालि پنجابی Papiamentu پښتو Patois Перем коми ភាសាខ្មែរ Piemontèis Plattdüütsch Polski Português Qaraqalpaqsha Ripoarisch Română Romani čhib Rumantsch Runa Simi Русский Саха тыла Sakizaya संस्कृतम् ᱥᱟᱱᱛᱟᱲᱤ Scots Shqip Sicilianu සිංහල Simple English سنڌي Slovenčina Slovenščina Ślůnski Soomaaliga کوردی Српски / srpski Srpskohrvatski / српскохрватски Sunda Suomi Svenska Tagalog தமிழ் Taclḥit Taqbaylit Татарча / tatarça Tayal తెలుగు ไทย Тоҷикӣ Türkçe Türkmençe Twi Tyap Українська اردو ئۇيغۇرچە / Uyghurche Vahcuengh Vepsän kel’ Tiếng Việt Võro Walon 文言 West-Vlams Winaray 吴语 Xitsonga ייִדיש Yorùbá 粵語 Zazaki Žemaitėška 中文 Edit links Article Talk English Read View source View history Tools Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote From Wikipedia, the free encyclopedia Species of hominid in the genus Homo Several terms redirect here. For other uses, see Human (disambiguation) , Mankind (disambiguation) , Humankind (disambiguation) , Human Race (disambiguation) , Human Being (disambiguation) , and Homo sapiens (disambiguation) . Human Temporal range: 0.3–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Chibanian – present Male (left) and female (right) adult humans, Thailand , 2007 Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Infraorder: Simiiformes Family: Hominidae Subfamily: Homininae Tribe: Hominini Genus: Homo Species: H. sapiens Binomial name Homo sapiens Linnaeus , 1758 Homo sapiens population density (2005) Humans ( Homo sapiens ) or modern humans are the most common and widespread species of primate , and the last surviving species of the genus Homo . They are great apes characterized by their hairlessness , bipedalism , and high intelligence . Humans have large brains , enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools , and form complex social structures and civilizations . Humans are highly social , with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states . As such, social interactions between humans have established a wide variety of values, social norms , languages , and traditions (collectively termed institutions ), each of which bolsters human society . Humans are also highly curious : the desire to understand and influence phenomena has motivated humanity's development of science , technology , philosophy , mythology , religion , and other frameworks of knowledge ; humans also study themselves through such domains as anthropology , social science , history , psychology , and medicine . As of April 2024, there are estimated to be more than 8 billion humans alive . Although some scientists equate the term "humans" with all members of the genus Homo , in common usage it generally refers to Homo sapiens , the only extant member. All other members of the genus Homo , which are now extinct, are known as archaic humans , and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa , they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence , interbreeding with Homo sapiens , or inability to adapt to climate change. For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution , which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement ; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change . Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle. Genes and the environment influence human biological variation in visible characteristics, physiology , disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic : generally, males have greater body strength and females have a higher body fat percentage. At puberty , humans develop secondary sex characteristics . Females are capable of pregnancy , usually between puberty, at around 12 years old, and menopause , around the age of 50. Humans are omnivorous , capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus . Humans can survive for up to eight weeks without food and several days without water . Humans are generally diurnal , sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death . Often, both the mother and the father provide care for their children, who are helpless at birth . Humans have a large, highly developed, and complex prefrontal cortex , the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory ; they have flexible facial expressions, self-awareness , and a theory of mind . The human mind is capable of introspection , private thought , imagination , volition , and forming views on existence . This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language . Etymology and definition Further information: Names for the human species and Human taxonomy Carl Linnaeus coined the name Homo sapiens All modern humans are classified into the species Homo sapiens , coined by Carl Linnaeus in his 1735 work Systema Naturae . The generic name " Homo " is a learned 18th-century derivation from Latin homō , which refers to humans of either sex. The word human can refer to all members of the Homo genus. The name " Homo sapiens " means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals , should be included as a separate species of humans or as a subspecies of H. sapiens . Human is a loanword of Middle English from Old French humain , ultimately from Latin hūmānus , the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity ) as well as to human males. It may also refer to individuals of either sex. Despite the fact that the word animal is colloquially used as an antonym for human , and contrary to a common biological misconception , humans are animals. The word person is often used interchangeably with human , but philosophical debate exists as to whether personhood applies to all humans or all sentient beings , and further if one can lose personhood (such as by going into a persistent vegetative state ). Evolution Main article: Human evolution Humans are apes ( superfamily Hominoidea ). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo ), then gorillas (genus Gorilla ), and finally, chimpanzees and bonobos (genus Pan ). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct. Reconstruction of Lucy , the first Australopithecus afarensis skeleton found The genus Homo evolved from Australopithecus . Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus . The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia , and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster ) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan . Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis , the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier. The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second ( Southern Dispersal ) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii , Easter Island , Madagascar , and New Zealand in the years 300 to 1280 CE. Human evolution was not a simple linear or branched progression but involved interbreeding between related species . Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans , may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans. Human evolution is characterized by a number of morphological , developmental , physiological , and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees . The most significant of these adaptations are hairlessness , obligate bipedalism, increased brain size and decreased sexual dimorphism ( neoteny ). The relationship between all these changes is the subject of ongoing debate. Hominoidea (hominoids, apes ) Hylobatidae ( gibbons ) Hominidae (hominids, great apes ) Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans) History Main article: Human history Prehistory Main article: Prehistory Overview map of the peopling of the world by early human migration during the Upper Paleolithic , following the Southern Dispersal paradigm Until about 12,000 years ago, all humans lived as hunter-gatherers . The Neolithic Revolution (the invention of agriculture ) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea , and the Sahel and West Savanna regions of Africa. Access to food surplus led to the formation of permanent human settlements , the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations . Ancient Main article: Ancient history Great Pyramids of Giza , Egypt An urban revolution took place in the 4th millennium BCE with the development of city-states , particularly Sumerian cities located in Mesopotamia . It was in these cities that the earliest known form of writing, cuneiform script , appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation . They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture , Minoans and the Shang dynasty , rose to prominence in new areas. The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages . During this period iron started replacing bronze, leading to the Iron Age . In the 5th century BCE, history started being recorded as a discipline , which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars . In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire 's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions. Medieval Main article: Post-classical history Medieval French manuscript illustration of the three classes of medieval society from the 13th-century Li Livres dou Santé Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages . During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age , inspiring achievements in architecture , the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England , the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims . In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast . Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific. Modern Main articles: Early modern period and Late modern period James Watt 's steam engine The early modern period in Europe and the Near East ( c. 1450 –1800) began with the final defeat of the Byzantine Empire , and the rise of the Ottoman Empire . Meanwhile, Japan entered the Edo period , the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance , starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas . This expansion led to the Atlantic slave trade and the genocide of Native American peoples . This period also marked the Scientific Revolution , with great advances in mathematics , mechanics , astronomy and physiology . The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology , major innovations in transport and energy development . The United States of America underwent great change, going from a small group of colonies to one of the global superpowers . The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World , while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania. A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War , one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War , involving almost all of the world's countries . The war's destruction led to the collapse of most global empires, leading to widespread decolonization. Contemporary Main article: Contemporary history Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race , ending in the collapse of the Soviet Union. The current Information Age , spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected. Habitat and population Further information: Human geography and Demography Population statistics Choropleth showing Population density (people per square kilometer) estimates by 30 arc-second grid in 2020 World population 8.1 billion Population density 16/km (41/sq mi) by total area 54/km (140/sq mi) by land area Largest cities Tokyo , Delhi , Shanghai , São Paulo , Mexico City , Cairo , Mumbai , Beijing , Dhaka , Osaka , New York - Newark , Karachi , Buenos Aires , Chongqing , Istanbul , Kolkata , Manila , Lagos , Rio de Janeiro , Tianjin , Kinshasa , Guangzhou , Los Angeles - Long Beach - Santa Ana , Moscow , Shenzhen , Lahore , Bangalore , Paris , Jakarta , Chennai , Lima , Bogota , Bangkok , London Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence , such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation , urban planning , construction, deforestation and desertification . Human settlements continue to be vulnerable to natural disasters , especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics , increasing knowledge or enhancing the exchange of resources. Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms , although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa , India , Russia , Australia , Fiji , United States and Brazil (each located in a different biogeographical realm). By using advanced tools and clothing , humans have been able to extend their tolerance to a wide variety of temperatures, humidities , and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest , arid desert , extremely cold arctic regions , and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth 's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%). Within the last century, humans have explored challenging environments such as Antarctica, the deep sea , and outer space . Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific , military , or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft . Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station . Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%. Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues , first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals. In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums . Humans have had a dramatic effect on the environment . They are apex predators , being rarely preyed upon by other species. Human population growth , industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life. Biology Anatomy and physiology Main article: Human body Basic anatomical features of female and male humans. These models have had body hair and male facial hair removed and head hair trimmed. Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.3 2.1.2.3 . Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth . Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars , with some individuals having them congenitally absent. Humans share with chimpanzees a vestigial tail, appendix , flexible shoulder joints, grasping fingers and opposable thumbs . Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling , hearing and digesting proteins . While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair , most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet. It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged . Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals. Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger. Genetics Main article: Human genetics A graphical representation of the standard human karyotype , including both the female (XX) and male (XY) sex chromosomes. Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes , each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes . Like other mammals, humans have an XY sex-determination system , so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood. While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years. The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms . African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas . By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA , which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve , must have lived around 90,000 to 200,000 years ago. Life cycle See also: Childbirth and Life expectancy A 10 mm human embryo at 5 weeks Most human reproduction takes place by internal fertilization via sexual intercourse , but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus . Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions. Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries. Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth , humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy , childhood , adolescence , adulthood and old age . The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis ), rather than by continuing to bear children into old age. The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018 , the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic , it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world , the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide. Human life stages Infant boy and girl Boy and girl before puberty ( children ) Adolescent male and female Adult man and woman Elderly man and woman Diet Main article: Human nutrition Humans living in Bali , Indonesia , preparing a meal Humans are omnivorous , capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous . In some cases, dietary restrictions in humans can lead to deficiency diseases ; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science . Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game , which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus . Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture , a gradual process called the Neolithic Revolution . These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture. In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation . Childhood malnutrition is also common and contributes to the global burden of disease . However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries . Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an " obesity epidemic ." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet. Biological variation Main article: Human genetic variation A Libyan , a Nubian , a Syrian , and an Egyptian , drawing by an unknown artist after a mural of the tomb of Seti I There is biological variation in the human species – with traits such as blood type , genetic diseases , cranial features , facial features , organ systems , eye color , hair color and texture , height and build , and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin , and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet , exercise, and sleep patterns . A variety of human hair colors; from top left, clockwise: black , brown , blonde , white , red . There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk . Sickle cell anemia , which may provide increased resistance to malaria , is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions , tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes . Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau . Human hair ranges in color from red to blond to brown to black , which is the most frequent. Hair color depends on the amount of melanin , with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach , or even nearly white or colorless in cases of albinism . It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D , which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation. There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other. Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa , and particularly West Africa , have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans. Humans are a gonochoric species, meaning they are divided into male and female sexes . The greatest degree of genetic variation exists between males and females . While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation . As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare. Psychology Main article: Psychology Drawing of the human brain , showing several important structures The human brain , the focal point of the central nervous system in humans, controls the peripheral nervous system . In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion , it is also the locus of "higher" order functioning such as thought , reasoning , and abstraction . These cognitive processes constitute the mind , and, along with their behavioral consequences, are studied in the field of psychology . Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition . This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to. There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in " mental time travel ". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind . Sleep and dreaming Main articles: Sleep and Dream Humans are generally diurnal . The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort. During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep . The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming , where the dreamer is self-aware . Dreams can at times make a creative thought occur or give a sense of inspiration . Consciousness and thought Main articles: Consciousness and Cognition Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection , private thought , imagination and volition . It now often includes some kind of experience , cognition , feeling or perception . It may be 'awareness', or ' awareness of awareness ', or self-awareness . There might be different levels or orders of consciousness , or different kinds of consciousness, or just one kind with different features. The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses , and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition , the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development . Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population. Motivation and emotion Main articles: Motivation and Emotion Illustration of grief from Charles Darwin 's 1872 book The Expression of the Emotions in Man and Animals Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization . Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure . They are often intertwined with mood , temperament , personality , disposition , creativity , and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal. Emotional experiences perceived as pleasant , such as joy , interest or contentment , contrast with those perceived as unpleasant , like anxiety , sadness , anger , and despair . Happiness , or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects , while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life . Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted. Sexuality and love Main articles: Human sexuality and Love Human parents often display familial love for their children. For humans, sexuality involves biological , erotic , physical , emotional , social , or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions , including the human sexual response cycle . Sexuality also affects and is affected by cultural, political, legal, philosophical, moral , ethical , and religious aspects of life. Sexual desire, or libido , is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often. Humans can fall anywhere along a continuous scale of sexual orientation , although most humans are heterosexual . While homosexual behavior occurs in some other animals , only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation , as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well. Love most commonly refers to a feeling of strong attraction or emotional attachment . It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine , norepinephrine , serotonin and other chemicals stimulate the brain's pleasure center , leading to side effects such as increased heart rate , loss of appetite and sleep , and an intense feeling of excitement . Culture Main articles: Culture and Cultural universal Human society statistics Most widely spoken languages English , Mandarin Chinese , Hindi , Spanish , Standard Arabic , Bengali , French , Russian , Portuguese , Urdu Most practiced religions Christianity , Islam , Hinduism , Buddhism , folk religions , Sikhism , Judaism , unaffiliated Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the " folk physics " required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning . Language Main article: Language Principal language families of the world (and in some cases geographic groups of families). For greater detail, see Distribution of languages in the world . While many species communicate , language is unique to humans, a defining feature of humanity, and a cultural universal . Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement , using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors. Language differs from other forms of communication in that it is modality independent ; the same meanings can be conveyed through different media, audibly in speech , visually by sign language or writing, and through tactile media such as braille . Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct . The arts Main article: The arts Human arts can take many forms including visual , literary , and performing . Visual art can range from paintings and sculptures to film , fashion design , and architecture . Literary arts can include prose , poetry , and dramas . The performing arts generally involve theatre , music , and dance . Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation , video games , and medicine . As well as providing entertainment and transferring knowledge, the arts are also used for political purposes . The Deluge tablet of the Gilgamesh epic in Akkadian Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage. Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures . There exists a wide variety of music genres and ethnic musics ; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment . Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain. Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh , first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation. Tools and technologies Main articles: Tool and Technology The SCMaglev , the fastest train in the world clocking in at 603 km/h (375 mph) as of 2015 Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated , thus proving essential in the development of agriculture – what is known as the Neolithic Revolution . China developed paper , the printing press , gunpowder , the compass and other important inventions . The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel , which is used in railways , skyscrapers and many other products. This coincided with the Industrial Revolution , where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially , with major innovations in the 20th century including: electricity , penicillin , semiconductors , internal combustion engines , the Internet , nitrogen fixing fertilisers , airplanes , computers , automobiles , contraceptive pills , nuclear fission , the green revolution , radio , scientific plant breeding , rockets , air conditioning , television and the assembly line . Religion and spirituality Main articles: Religion and Spirituality Shango , the Orisha of fire, lightning, and thunder, in the Yoruba religion , depicted on horseback Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural , sacred or divine , and practices, values , institutions and rituals associated with such belief. Some religions also have a moral code . The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago ). It may have evolved to play a role in helping enforce and encourage cooperation between humans. Religion manifests in diverse forms. Religion can include a belief in life after death , the origin of life , the nature of the universe ( religious cosmology ) and its ultimate fate ( eschatology ), and moral or ethical teachings . Views on transcendence and immanence vary substantially; traditions variously espouse monism , deism , pantheism , and theism (including polytheism and monotheism ). Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims , Hindus and Buddhists . As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious , including those with no religious beliefs or no identity with any religion. Science and philosophy Main articles: Science and Philosophy The Dunhuang map , a star map showing the North Polar region. China circa 700. An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy. Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period . Other early advances in science came from the Han dynasty in China and during the Islamic Golden Age . The scientific revolution , near the end of the Renaissance , led to the emergence of modern science . A chain of events and influences led to the development of the scientific method , a process of observation and experimentation that is used to differentiate science from pseudoscience . An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition . All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics ), which are concerned with formal systems , the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics , chemistry , biology ) and social sciences (e.g., psychology , economics, sociology). Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics , epistemology , logic , and axiology (which includes ethics and aesthetics ). Society Main article: Society Humans often live in family-based social structures Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power , reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies . Gender Main article: Gender Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex . The most common categorisation is a gender binary of men and women . Some societies recognise a third gender , or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female. Gender roles are often associated with a division of norms , practices , dress , behavior , rights , duties , privileges , status , and power , with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct , gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic , while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal. Kinship Main article: Kinship All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants ( consanguinity ), and relations through marriage ( affinity ). There is also a third type applied to godparents or adoptive children ( fictive ). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance . All societies have rules of incest taboo , according to which marriage between certain kinds of kin relations is prohibited, and some also have rules of preferential marriage with certain kin relations. Ethnicity Main article: Ethnic group Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry , language , history , society , culture , nation , religion , or social treatment within their residing area. Ethnicity is separate from the concept of race , which is based on physical characteristics, although both are socially constructed . Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries. Government and politics Main articles: Government and Politics The United Nations headquarters in New York City, which houses one of the world's largest political organizations As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances. Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy , 17% in a hybrid regime , and 37% in an authoritarian regime . Many countries belong to international organizations and alliances ; the largest of these is the United Nations , with 193 member states . Trade and economics Main articles: Trade and Economics The Silk Road (red) and spice trade routes (blue) Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian . The first truly international trade routes were around the spice trade through the Roman and medieval periods. Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities ; the oldest being in the form of cattle and the most widely used being cowrie shells . Money has since evolved into governmental issued coins , paper and electronic money . Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population. Conflict Main article: Conflict (process) American troops landing at Normandy , WWII. Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered , rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations, with rates of homicide about 0.01% in societies that have legal systems and strong cultural attitudes against violence. The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war ) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict. See also Mammals portal Evolutionary biology portal Science portal List of human evolution fossils Timeline of human evolution Notes ^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects. ^ Cities with over 10 million inhabitants as of 2018. ^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that. References ^ Groves CP (2005). Wilson DE , Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4 . OCLC 62265494 . ^ Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences . 149 (1): 109–114. JSTOR 4065043 . ^ Porkorny (1959). IEW . s.v. "g'hðem" pp. 414–116. ^ "Homo" . Dictionary.com Unabridged (v 1.1) . Random House. 23 September 2008. Archived from the original on 27 September 2008. ^ Barras, Colin (11 January 2016). "We don't know which species should be classed as 'human' " . BBC . Archived from the original on 26 August 2021 . Retrieved 31 March 2021 . ^ Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758" . Proceedings of the Academy of Natural Sciences of Philadelphia . 149 : 109–114. ISSN 0097-3157 . JSTOR 4065043 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . ^ OED . s.v. "human". ^ "Man" . Merriam-Webster Dictionary . Archived from the original on 22 September 2017 . Retrieved 14 September 2017 . Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination ^ "Thesaurus results for human" . Merriam-Webster Dictionary . Archived from the original on 28 June 2022 . Retrieved 21 May 2022 . ^ "Misconceptions about evolution – Understanding Evolution" . University of California, Berkeley . 19 September 2021. Archived from the original on 6 June 2022 . Retrieved 21 May 2022 . ^ "Concept of Personhood" . University of Missouri School of Medicine . Archived from the original on 4 March 2021 . Retrieved 4 July 2021 . ^ Tuttle RH (4 October 2018). "Hominoidea: conceptual history" . In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology . Hoboken , New Jersey , United States : John Wiley & Sons, Inc. pp. 1–2. doi : 10.1002/9781118584538.ieba0246 . ISBN 978-1-118-58442-2 . S2CID 240125199 . Retrieved 26 May 2021 . ^ Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution . 30 (3): 260–266. Bibcode : 1990JMolE..30..260G . doi : 10.1007/BF02099995 . PMID 2109087 . S2CID 2112935 . ^ Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets" . Molecular Biology and Evolution . 14 (3): 248–265. doi : 10.1093/oxfordjournals.molbev.a025761 . PMID 9066793 . ^ MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes" . Evolution pages . Archived from the original on 9 August 2011 . Retrieved 18 May 2006 . ^ McNulty, Kieran P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?" . Nature Education Knowledge . Archived from the original on 10 January 2016 . Retrieved 11 June 2022 . ^ Strait DS (September 2010). "The Evolutionary History of the Australopiths" . Evolution: Education and Outreach . 3 (3): 341–352. doi : 10.1007/s12052-010-0249-6 . ISSN 1936-6434 . S2CID 31979188 . ^ Dunsworth HM (September 2010). "Origin of the Genus Homo" . Evolution: Education and Outreach . 3 (3): 353–366. doi : 10.1007/s12052-010-0247-8 . ISSN 1936-6434 . S2CID 43116946 . ^ Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1698): 20150248. doi : 10.1098/rstb.2015.0248 . PMC 4920303 . PMID 27298460 . S2CID 20267830 . ^ Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia" . Science . 347 (6228): 1352–1355. Bibcode : 2015Sci...347.1352V . doi : 10.1126/science.aaa1343 . PMID 25739410 . ^ Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature . 559 (7715): 608–612. Bibcode : 2018Natur.559..608Z . doi : 10.1038/s41586-018-0299-4 . PMID 29995848 . S2CID 49670311 . ^ Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF) . Nature . 546 (7657): 289–292. Bibcode : 2017Natur.546..289H . doi : 10.1038/nature22336 . PMID 28593953 . S2CID 256771372 . Archived (PDF) from the original on 8 January 2020 . Retrieved 30 July 2022 . ^ "Out of Africa Revisited". Science (This Week in Science ). 308 (5724): 921. 13 May 2005. doi : 10.1126/science.308.5724.921g . ISSN 0036-8075 . S2CID 220100436 . ^ Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature . 423 (6941): 692–693, 695. Bibcode : 2003Natur.423..692S . doi : 10.1038/423692a . PMID 12802315 . S2CID 26693109 . ^ Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?" . actionbioscience . Washington, DC: American Institute of Biological Sciences . Archived from the original on 17 June 2021 . Retrieved 23 November 2009 . ^ Marean, Curtis; et al. (2007). "Early human use of marine resources and pigment in South Africa during the Middle Pleistocene" (PDF) . Nature . 449 (7164): 905–908. Bibcode : 2007Natur.449..905M . doi : 10.1038/nature06204 . PMID 17943129 . S2CID 4387442 . Archived (PDF) from the original on 2023-05-25 . Retrieved 2023-01-07 . ^ Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB (2018). "Long-distance stone transport and pigment use in the earliest Middle Stone Age" . Science . 360 (6384): 90–94. Bibcode : 2018Sci...360...90B . doi : 10.1126/science.aao2646 . PMID 29545508 . ^ Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology . 26 (6): 827–833. Bibcode : 2016CBio...26..827P . doi : 10.1016/j.cub.2016.01.037 . hdl : 2440/114930 . PMID 26853362 . S2CID 140098861 . ^ Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture" . Genome Research . 25 (4): 459–466. doi : 10.1101/gr.186684.114 . PMC 4381518 . PMID 25770088 . ^ Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia" . Science . 331 (6016): 453–456. Bibcode : 2011Sci...331..453A . doi : 10.1126/science.1199113 . PMID 21273486 . S2CID 20296624 . Archived from the original on 27 April 2011 . Retrieved 1 May 2011 . ^ Rincon P (27 January 2011). "Humans 'left Africa much earlier' " . BBC News . Archived from the original on 9 August 2012. ^ Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature . 547 (7663): 306–310. Bibcode : 2017Natur.547..306C . doi : 10.1038/nature22968 . hdl : 2440/107043 . PMID 28726833 . S2CID 205257212 . ^ Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF) . University of Waikato . Archived (PDF) from the original on 22 May 2010 . Retrieved 29 April 2010 . ^ Appenzeller T (May 2012). "Human migrations: Eastern odyssey" . Nature . 485 (7396): 24–26. Bibcode : 2012Natur.485...24A . doi : 10.1038/485024a . PMID 22552074 . ^ Reich D , Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" . Nature . 468 (7327): 1053–1060. Bibcode : 2010Natur.468.1053R . doi : 10.1038/nature09710 . hdl : 10230/25596 . PMC 4306417 . PMID 21179161 . ^ Hammer MF (May 2013). "Human Hybrids" (PDF) . Scientific American . 308 (5): 66–71. Bibcode : 2013SciAm.308e..66H . doi : 10.1038/scientificamerican0513-66 . PMID 23627222 . Archived from the original (PDF) on 24 August 2018. ^ Yong E (July 2011). "Mosaic humans, the hybrid species" . New Scientist . 211 (2823): 34–38. Bibcode : 2011NewSc.211...34Y . doi : 10.1016/S0262-4079(11)61839-3 . ^ Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology . 43 (1): 1–11. doi : 10.1007/s11692-015-9348-1 . S2CID 14329491 . ^ Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans" . Genome Research . 20 (5): 547–553. doi : 10.1101/gr.076000.108 . PMC 2860157 . PMID 20439435 . ^ Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans" . Science . 334 (6052): 89–94. Bibcode : 2011Sci...334...89A . doi : 10.1126/science.1209202 . PMC 3677943 . PMID 21868630 . ^ Sandel, Aaron A. (30 July 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness" . American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . Archived from the original on 22 July 2023 . Retrieved 22 July 2023 . ^ Boyd R , Silk JB (2003). How Humans Evolved . New York: Norton . ISBN 978-0-393-97854-4 . ^ Little, Michael A.; Blumler, Mark A. (2015). "Hunter-Gatherers" . In Muehlenbein, Michael P. (ed.). Basics in Human Evolution . Boston: Academic Press. pp. 323–335. ISBN 978-0-12-802652-6 . Archived from the original on 3 July 2022 . Retrieved 30 July 2022 . ^ Scarre, Chris (2018). "The world transformed: from foragers and farmers to states and empires". In Scarre, Chris (ed.). The Human Past: World Prehistory and the Development of Human Societies (4th ed.). London: Thames & Hudson . pp. 174–197. ISBN 978-0-500-29335-5 . ^ Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe . Walnut Creek, CA: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5 . OCLC 855969933 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society . Elsevier. pp. 103–131. doi : 10.1016/B978-0-12-805247-1.00006-X . ISBN 978-0-12-805247-1 . ^ He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China" . The Holocene . 27 (12): 1885–1898. Bibcode : 2017Holoc..27.1885H . doi : 10.1177/0959683617708455 . S2CID 133660098 . Archived from the original on 20 November 2021 . Retrieved 30 July 2022 . ^ Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago" . Proceedings of the National Academy of Sciences of the United States of America . 106 (18): 7367–7372. Bibcode : 2009PNAS..106.7367L . doi : 10.1073/pnas.0900158106 . PMC 2678631 . PMID 19383791 . ^ Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea" . Science . 301 (5630): 189–193. doi : 10.1126/science.1085255 . PMID 12817084 . S2CID 10644185 . ^ Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication" . Science Advances . 5 (5): eaaw1947. Bibcode : 2019SciA....5.1947S . doi : 10.1126/sciadv.aaw1947 . PMC 6527260 . PMID 31114806 . ^ Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF) . Current Anthropology . 58 (5): 673–683. doi : 10.1086/693898 . S2CID 149402650 . Archived (PDF) from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science . 38 (2): 312–322. Bibcode : 2011JArSc..38..312M . doi : 10.1016/j.jas.2010.09.007 . ^ Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries . Cengage Learning. ISBN 978-1-285-66153-7 . Archived from the original on 27 February 2021 . Retrieved 11 July 2015 . ^ Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500 . Cenpage Learning. ISBN 978-1-285-98299-1 . Archived from the original on 10 August 2023 . Retrieved 11 July 2015 . ^ Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization . San Francisco: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3 . Archived from the original on 10 August 2023 . Retrieved 30 July 2022 . ^ Garfinkle, Steven J. (2013). "Ancient Near Eastern City-States". In Peter Fibiger Bang ; Walter Scheidel (eds.). The Oxford Handbook of the State in the Ancient Near East and Mediterranean . Oxford Academic. pp. 94–119. doi : 10.1093/oxfordhb/9780195188318.013.0004 . ISBN 978-0-19-518831-8 . ^ Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi : 10.1002/9781119193814.ch2 . ISBN 978-1-119-19329-6 . S2CID 216180781 . ^ Robinson A (October 2015). "Ancient civilization: Cracking the Indus script" . Nature . 526 (7574): 499–501. Bibcode : 2015Natur.526..499R . doi : 10.1038/526499a . PMID 26490603 . S2CID 4458743 . ^ Crawford H (2013). "Trade in the Sumerian world". The Sumerian World . Routledge. pp. 447–461. ISBN 978-1-136-21911-5 . ^ Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles" . Acta Archaeologica Academiae Scientiarum Hungaricae . 69 (2): 271–298. doi : 10.1556/072.2018.69.2.3 . ISSN 0001-5210 . S2CID 115685157 . Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Pryor FL (1985). "The Invention of the Plow" . Comparative Studies in Society and History . 27 (4): 727–743. doi : 10.1017/S0010417500011749 . ISSN 0010-4175 . JSTOR 178600 . S2CID 144840498 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Carter R (2012). "19. Watercraft ". In Potts DT (ed.). A companion to the archaeology of the ancient Near East . Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0 . Archived from the original on 28 April 2015 . Retrieved 8 February 2014 . ^ Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction . CUP Archive. p. 1. ISBN 978-0-521-40340-5 . ^ Robson E (2008). Mathematics in ancient Iraq: A social history . Princeton University Press. pp. xxi. ^ Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza" . Technology and Culture . 44 (2): 340–354. doi : 10.1353/tech.2003.0063 . ISSN 0040-165X . JSTOR 25148110 . S2CID 109998651 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Voosen P (August 2018). "New geological age comes under fire". Science . 361 (6402): 537–538. Bibcode : 2018Sci...361..537V . doi : 10.1126/science.361.6402.537 . PMID 30093579 . S2CID 51954326 . ^ Saggs HW (2000). Babylonians . Univ of California Press. p. 7. ISBN 978-0-520-20222-1 . ^ Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory . 12 (4): 335–364. doi : 10.1007/s10816-005-8460-4 . ISSN 1573-7764 . S2CID 53393440 . ^ Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans" . Nature . 548 (7666): 214–218. Bibcode : 2017Natur.548..214L . doi : 10.1038/nature23310 . PMC 5565772 . PMID 28783727 . ^ Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC . Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8 . ^ Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change . 6 (4): 369–382. Bibcode : 2015WIRCC...6..369K . doi : 10.1002/wcc.345 . S2CID 128460316 . ^ Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science . 39 (6): 1862–1870. Bibcode : 2012JArSc..39.1862D . doi : 10.1016/j.jas.2012.01.029 . ^ Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory . Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi : 10.1007/978-1-4419-6633-9_11 . ISBN 978-1-4419-6633-9 . ^ Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography . United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1 . ^ Beard M (2 October 2015). "Why ancient Rome matters to the modern world" . The Guardian . Archived from the original on 14 April 2021 . Retrieved 17 April 2021 . ^ Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece" . Stanford University . Archived from the original on 18 April 2021 . Retrieved 17 April 2021 . ^ Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature . 582 (7813): 530–533. Bibcode : 2020Natur.582..530I . doi : 10.1038/s41586-020-2343-4 . PMID 32494009 . S2CID 219281856 . ^ Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar" . Latin American Antiquity . 28 (1): 88–104. doi : 10.1017/laq.2016.4 . ISSN 1045-6635 . S2CID 164417025 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida" . Proceedings of the Seminar for Arabian Studies . 46 : 25–40. ISSN 0308-8421 . JSTOR 45163415 . Archived from the original on 28 April 2022 . Retrieved 30 July 2022 . ^ Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration . 21 (1): 25–86. doi : 10.1080/01900699808525297 . ISSN 0190-0692 . ^ Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age" . Journal of the American Oriental Society . 96 (1): 15–26. doi : 10.2307/599886 . ISSN 0003-0279 . JSTOR 599886 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty" . Architectural History . 63 : 1–36. doi : 10.1017/arh.2020.1 . ISSN 0066-622X . S2CID 229716130 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question" . Climate . 6 (4): 90. Bibcode : 2018Clim....6...90M . doi : 10.3390/cli6040090 . ^ Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World . New York: Oxford University Press. p. 72. ISBN 978-0-19-532819-6 . Retrieved 30 July 2022 . ^ Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies . International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi : 10.1007/978-3-319-24774-8_2 . ISBN 978-3-319-24774-8 . ^ Vidal-Nanquet P (1987). The Harper Atlas of World History . Harper & Row Publishers. p. 76. ^ Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land . Simon and Schuster. ISBN 978-1-84983-770-5 . ^ Adam King (2002). "Mississippian Period: Overview" . New Georgia Encyclopedia . Archived from the original on 19 August 2009 . Retrieved 15 November 2009 . ^ Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism . Cambridge University Press. p. 2. ISBN 0-521-31896-3 . ^ May T (2013). The Mongol Conquests in World History . Reaktion Books. p. 7. ISBN 978-1-86189-971-2 . ^ Canós-Donnay S (25 February 2019). "The Empire of Mali" . Oxford Research Encyclopedia of African History . Oxford University Press. doi : 10.1093/acrefore/9780190277734.013.266 . ISBN 978-0-19-027773-4 . Archived from the original on 20 October 2021 . Retrieved 7 May 2021 . ^ Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity" . Asian Perspectives . 37 (2): 135–164. ^ Kafadar C (1 January 1994). "Ottomans and Europe" . In Brady T, Oberman T, Tracy JD (eds.). Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation . Brill. pp. 589–635. doi : 10.1163/9789004391659_019 . ISBN 978-90-04-39165-9 . Archived from the original on 2 May 2022 . Retrieved 17 April 2021 . ^ Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan" . Oxford Research Encyclopedia of Asian History . Oxford University Press. doi : 10.1093/acrefore/9780190277727.013.72 . ISBN 978-0-19-027772-7 . Archived from the original on 12 August 2021 . Retrieved 7 May 2021 . ^ Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing" . Pacific Affairs . 83 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526–1857)" . Al-Ta Lim Journal . 23 (2): 128–138. doi : 10.15548/jt.v23i2.228 . ISSN 2355-7893 . Archived from the original on 7 April 2022 . Retrieved 30 July 2022 . ^ Kirkpatrick R (2002). The European Renaissance, 1400–1600 . Routledge. p. 1. ISBN 978-1-317-88646-4 . OCLC 893909816 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Arnold D (2002). The Age of Discovery, 1400–1600 (Second ed.). Routledge. pp. xi. ISBN 978-1-136-47968-7 . OCLC 859536800 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics" . Theoretical Inquiries in Law . 11 (1). doi : 10.2202/1565-3404.1239 . ISSN 1565-3404 . S2CID 56216309 . Archived from the original on 26 August 2021 . Retrieved 30 July 2022 . ^ Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews . 20 (1–3): 277–299. Bibcode : 2001QSRv...20..277J . doi : 10.1016/S0277-3791(00)00116-5 . ^ Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature" . The Journal of African History . 30 (3): 365–394. doi : 10.1017/S0021853700024439 . ISSN 0021-8537 . JSTOR 182914 . S2CID 161321949 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide . London: Palgrave Macmillan UK. pp. 273–295. doi : 10.1057/9780230297784_11 . ISBN 978-0-230-29778-4 . ^ Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour . 38 (3–4): 157–158. doi : 10.1016/j.endeavour.2014.10.001 . PMID 25457642 . ^ "Greatest Engineering Achievements of the 20th Century" . National Academy of Engineering . Archived from the original on 6 April 2015 . Retrieved 7 April 2015 . ^ Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776 . New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0 . OCLC 299054528 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815" . Journal of Global History . 1 (1): 123–149. doi : 10.1017/S1740022806000076 . ISSN 1740-0228 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Zimmerman AF (November 1931). "Spain and Its Colonies, 1808–1820" . The Hispanic American Historical Review . 11 (4): 439–463. doi : 10.2307/2506251 . JSTOR 2506251 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ David S (2011). "British History in depth: Slavery and the 'Scramble for Africa' " . BBC . Archived from the original on 24 March 2022 . Retrieved 5 May 2021 . ^ Raudzens G (2004). "The Australian Frontier Wars, 1788–1838 (review)" . The Journal of Military History . 68 (3): 957–959. doi : 10.1353/jmh.2004.0138 . ISSN 1543-7795 . S2CID 162259092 . ^ Clark CM (2012). "Polarization of Europe, 1887–1907". The sleepwalkers : how Europe went to war in 1914 . London: Allen Lane. ISBN 978-0-7139-9942-6 . OCLC 794136314 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Robert Dahl (1989). Democracy and Its Critics . Yale UP. pp. 239–240 . ISBN 0-300-15355-4 . ^ McDougall WA (May 1985). "Sputnik, the space race, and the Cold War" . Bulletin of the Atomic Scientists . 41 (5): 20–25. Bibcode : 1985BuAtS..41e..20M . doi : 10.1080/00963402.1985.11455962 . ISSN 0096-3402 . ^ Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?" . Journal of Peace Research . 30 (2): 163–179. doi : 10.1177/0022343393030002004 . ISSN 0022-3433 . S2CID 5482851 . Archived from the original on 21 February 2022 . Retrieved 30 July 2022 . ^ Sachs JD (April 2017). "Globalization – In the Name of Which Freedom?" . Humanistic Management Journal . 1 (2): 237–252. doi : 10.1007/s41463-017-0019-5 . ISSN 2366-603X . S2CID 133030709 . ^ "World" . The World Factbook . CIA . 17 May 2016. Archived from the original on 26 January 2021 . Retrieved 2 October 2016 . ^ "World Population Prospects: The 2017 Revision" (PDF) . United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17. Archived (PDF) from the original on 26 June 2019 . Retrieved 30 July 2022 . ^ "The World's Cities in 2018" (PDF) . United Nations . Archived (PDF) from the original on 1 November 2018. ^ Rector RK (2016). The Early River Valley Civilizations (First ed.). New York: Rosen Publishing. p. 10. ISBN 978-1-4994-6329-3 . OCLC 953735302 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ "How People Modify the Environment" (PDF) . Westerville City School District . Archived (PDF) from the original on 25 February 2021 . Retrieved 13 March 2019 . ^ "Natural disasters and the urban poor" (PDF) . World Bank . October 2003. Archived (PDF) from the original on 9 August 2017. ^ Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities . [London]: Routledge. pp. x. ISBN 978-1-135-01559-6 . OCLC 889953315 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Piantadosi CA (2003). The biology of human survival : life and death in extreme environments . Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5 . OCLC 70215878 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Toups, M.A.; Kitchen, A.; Light, J.E.; Reed, D.L. (2011). "Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa" . Molecular Biology and Evolution . 28 (1): 29–32. doi : 10.1093/molbev/msq234 . PMC 3002236 . PMID 20823373 . ^ O'Neil D. "Human Biological Adaptability; Overview" . Palomar College. Archived from the original on 6 March 2013 . Retrieved 6 January 2013 . ^ "Population distribution and density" . BBC. Archived from the original on 23 June 2017 . Retrieved 26 June 2017 . ^ Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management . 30 (4): 492–507. doi : 10.1007/s00267-002-2737-0 . hdl : 10072/6758 . PMID 12481916 . S2CID 25834286 . ^ Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica" . Vanderbilt Journal of Transnational Law . 23 : 819. Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ "Mission to Mars: Mars Science Laboratory Curiosity Rover" . Jet Propulsion Laboratory. Archived from the original on 18 August 2015 . Retrieved 26 August 2015 . ^ "Touchdown! Rosetta's Philae probe lands on comet" . European Space Agency. 12 November 2014. Archived from the original on 22 August 2015 . Retrieved 26 August 2015 . ^ "NEAR-Shoemaker" . NASA . Archived from the original on 26 August 2015 . Retrieved 26 August 2015 . ^ Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station" . JSC Features . Johnson Space Center . Archived from the original on 16 February 2012 . Retrieved 13 February 2012 . ^ Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth" . Proceedings of the National Academy of Sciences of the United States of America . 115 (25): 6506–6511. Bibcode : 2018PNAS..115.6506B . doi : 10.1073/pnas.1711842115 . PMC 6016768 . PMID 29784790 . ^ Tellier LN (2009). Urban world history: an economic and geographical perspective . Presses de l'Université du Québec. p. 26. ISBN 978-2-7605-1588-8 . Retrieved 30 July 2022 . ^ Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, CA: Dickenson Pub. Co. ISBN 978-0-8221-0166-6 . ^ Harl KW (1998). "Population estimates of the Roman Empire" . Tulane.edu. Archived from the original on 7 May 2016 . Retrieved 8 December 2012 . ^ Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis" . International Journal of Hygiene and Environmental Health . 207 (2): 165–178. doi : 10.1078/1438-4639-00259 . PMC 7128933 . PMID 15031959 . ^ "World's population reaches six billion" . BBC News . 5 August 1999. Archived from the original on 15 April 2008 . Retrieved 5 February 2008 . ^ United Nations. "World population to reach 8 billion on 15 November 2022" . United Nations . Archived from the original on 20 January 2023 . Retrieved 27 October 2022 . ^ "Eight billion people, SARS-CoV-2 ancestor and illegal fishing" . Nature . 611 (641): 641. 23 November 2022. Bibcode : 2022Natur.611..641. . doi : 10.1038/d41586-022-03792-4 . S2CID 253764233 . Archived from the original on 26 January 2023 . Retrieved 26 January 2023 . ^ "World Population to Hit Milestone With Birth of 7 Billionth Person" . PBS NewsHour . 27 October 2011. Archived from the original on 24 September 2017 . Retrieved 11 February 2018 . ^ "68% of the world population projected to live in urban areas by 2050, says UN" . United Nations Department of Economic and Social Affairs (DESA) . 16 May 2018. Archived from the original on 10 March 2021 . Retrieved 18 April 2021 . ^ Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF) . U.S. Department of Justice , Bureau of Justice Statistics. Archived (PDF) from the original on 24 February 2013 . Retrieved 1 October 2006 . ^ Roopnarine PD (March 2014). "Humans are apex predators" . Proceedings of the National Academy of Sciences of the United States of America . 111 (9): E796. Bibcode : 2014PNAS..111E.796R . doi : 10.1073/pnas.1323645111 . PMC 3948303 . PMID 24497513 . ^ Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature" . Science . AAAS . Archived from the original on 26 October 2021 . Retrieved 9 May 2021 . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use – principally agriculture – that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.) ^ Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions" . Proceedings of the National Academy of Sciences of the United States of America . 103 (29): 10941–10946. Bibcode : 2006PNAS..10310941P . doi : 10.1073/pnas.0604181103 . PMC 1544153 . PMID 16829570 . ^ Collins D (1976). The Human Revolution: From Ape to Artist . Phaidon. p. 208 . ISBN 978-0-7148-1676-0 . ^ Weisberger, Mindy (March 23, 2024). "Why don't humans have tails? Scientists find answers in an unlikely place" . CNN . Archived from the original on March 24, 2024 . Retrieved March 24, 2024 . ^ Marks JM (2001). Human Biodiversity: Genes, Race, and History . Transaction Publishers. p. 16. ISBN 978-0-202-36656-2 . ^ Gea, J (2008). "The Evolution of the Human Species: A Long Journey for the Respiratory System". Archivos de Bronconeumología ((English Edition)) . 44 (5): 263–270. doi : 10.1016/S1579-2129(08)60042-7 . ^ O'Neil D. "Humans" . Primates . Palomar College. Archived from the original on 11 January 2013 . Retrieved 6 January 2013 . ^ "How to be Human: The reason we are so scarily hairy" . New Scientist . 2017. Archived from the original on 25 February 2021 . Retrieved 29 April 2020 . ^ Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . ^ Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White" . Evolution: Library . PBS. Archived from the original on 16 February 2013 . Retrieved 6 January 2013 . ^ Roser M, Appel C, Ritchie H (8 October 2013). "Human Height" . Our World in Data . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ "Senior Citizens Do Shrink – Just One of the Body Changes of Aging" . News . Senior Journal. Archived from the original on 19 February 2013 . Retrieved 6 January 2013 . ^ Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology . 136 (1): 71–84. doi : 10.1016/S1095-6433(02)00294-5 . PMID 14527631 . ^ "Human weight" . Articleworld.org. Archived from the original on 8 December 2011 . Retrieved 10 December 2011 . ^ Schlessingerman A (2003). "Mass Of An Adult" . The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018 . Retrieved 31 December 2017 . ^ Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology) . Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1 . Retrieved 5 April 2009 . ^ Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care" . British Journal of Anaesthesia . 85 (1): 91–108. doi : 10.1093/bja/85.1.91 . PMID 10927998 . ^ Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology . 93 (1): 1–16. doi : 10.1086/696721 . ISSN 0033-5770 . S2CID 90757192 . ^ Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance" . The New York Times . Archived from the original on 5 November 2015. ^ John B. "What is the role of sweating glands in balancing body temperature when running a marathon?" . Livestrong.com. Archived from the original on 31 January 2013 . Retrieved 6 January 2013 . ^ Shave, R. E.; Lieberman, D. E.; Drane, A. L.; et al. (2019). "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart" . PNAS . 116 (40): 19905–19910. Bibcode : 2019PNAS..11619905S . doi : 10.1073/pnas.1906902116 . PMC 6778238 . PMID 31527253 . ^ Ríos, L; Sleeper, M. M.; Danforth, M. D.; et al. (2023). "The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution" . Scientific Reports . 13 (6841): 6841. Bibcode : 2023NatSR..13.6841R . doi : 10.1038/s41598-023-33675-1 . hdl : 10261/309357 . PMC 10133235 . PMID 37100851 . ^ Therman E (1980). Human Chromosomes: Structure, Behavior, Effects . Springer US . pp. 112–124. doi : 10.1007/978-1-4684-0107-3 . ISBN 978-1-4684-0109-7 . S2CID 36686283 . ^ Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex" . Journal of Medical Genetics . 3 (2): 117–123. doi : 10.1136/jmg.3.2.117 . PMC 1012913 . PMID 6007033 . ^ Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics . 61 (3): 216–228. doi : 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S . PMID 8741866 . ^ Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics . 53 (1): 27–34. doi : 10.1038/s41588-020-00755-1 . PMID 33414551 . S2CID 230986741 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . Between any two humans, the amount of genetic variation – biochemical individuality – is about 0.1%. ^ Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human" . PLOS Biology . 5 (10): e254. doi : 10.1371/journal.pbio.0050254 . PMC 1964779 . PMID 17803354 . ^ Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research" . American Journal of Human Genetics . 77 (4): 519–532. doi : 10.1086/491747 . PMC 1275602 . PMID 16175499 . ^ "Chimps show much greater genetic diversity than humans" . Media . University of Oxford. Archived from the original on 18 December 2013 . Retrieved 13 December 2013 . ^ Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography" . Proceedings of the National Academy of Sciences of the United States of America . 95 (4): 1961–1967. Bibcode : 1998PNAS...95.1961H . doi : 10.1073/pnas.95.4.1961 . PMC 19224 . PMID 9465125 . ^ Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans" . Proceedings of the National Academy of Sciences of the United States of America . 94 (7): 3100–3103. Bibcode : 1997PNAS...94.3100J . doi : 10.1073/pnas.94.7.3100 . PMC 20328 . PMID 9096352 . ^ Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story" . The New York Times . Archived from the original on 14 January 2012 . Retrieved 13 February 2012 . ^ Pennisi E (February 2001). "The human genome". Science . 291 (5507): 1177–1180. doi : 10.1126/science.291.5507.1177 . PMID 11233420 . S2CID 38355565 . ^ Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature . 590 (7845): 220–221. Bibcode : 2021Natur.590..220R . doi : 10.1038/d41586-021-00237-2 . PMID 33568827 . S2CID 231882262 . ^ Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations" . Nature . 467 (7311): 52–58. Bibcode : 2010Natur.467...52T . doi : 10.1038/nature09298 . PMC 3173859 . PMID 20811451 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private , common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture. ^ Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes" . Genome Biology . 11 (5): 206. doi : 10.1186/gb-2010-11-5-206 . PMC 2898077 . PMID 20441615 . ^ Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature . 325 (6099): 31–36. Bibcode : 1987Natur.325...31C . doi : 10.1038/325031a0 . PMID 3025745 . S2CID 4285418 . ^ Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock" . American Journal of Human Genetics . 84 (6): 740–759. doi : 10.1016/j.ajhg.2009.05.001 . PMC 2694979 . PMID 19500773 . ^ "University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history" . 20 August 2017. Archived from the original on 20 August 2017. ^ Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females" . Science . 341 (6145): 562–565. Bibcode : 2013Sci...341..562P . doi : 10.1126/science.1237619 . PMC 4032117 . PMID 23908239 . ^ Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set . John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1 . ^ Jukic AM, Baird DD, Weinberg CR , McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation" . Human Reproduction . 28 (10): 2848–2855. doi : 10.1093/humrep/det297 . PMC 3777570 . PMID 23922246 . ^ Klossner NJ (2005). Introductory Maternity Nursing . Lippincott Williams & Wilkins. p. 103. ISBN 978-0-7817-6237-3 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . The fetal stage is from the beginning of the 9th week after fertilization and continues until birth ^ World Health Organization (November 2014). "Preterm birth Fact sheet N°363" . who.int . Archived from the original on 7 March 2015 . Retrieved 6 March 2015 . ^ Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application" . American Journal of Obstetrics and Gynecology . 218 (2S): S619–S629. doi : 10.1016/j.ajog.2017.12.010 . PMID 29422204 . S2CID 46810955 . ^ "What is the average baby length? Growth chart by month" . www.medicalnewstoday.com . 18 March 2019. Archived from the original on 27 January 2021 . Retrieved 18 April 2021 . ^ Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal . 5 (2): 113–122. PMID 15024783 . ^ Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology . 35 (S15): 89–124. doi : 10.1002/ajpa.1330350605 . ISSN 1096-8644 . ^ Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma" . American Journal of Obstetrics and Gynecology . 222 (1): 3–16. doi : 10.1016/j.ajog.2019.06.043 . PMC 9069416 . PMID 31251927 . S2CID 195761874 . ^ Barras C (22 December 2016). "The real reasons why childbirth is so painful and dangerous". BBC. ^ Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?" . Newsweek . Archived from the original on 28 June 2007. A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa , compared to 1 in 2,800 in developed countries . ^ Rush D (July 2000). "Nutrition and maternal mortality in the developing world" . The American Journal of Clinical Nutrition . 72 (1 Suppl): 212S–240S. doi : 10.1093/ajcn/72.1.212S . PMID 10871588 . ^ Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour . Oxford University Press. p. 7. ISBN 978-0-19-958696-7 . Retrieved 30 July 2022 . ^ Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning . p. 296. ISBN 978-0-495-60037-4 . Archived from the original on 3 October 2023 . Retrieved 30 July 2022 . ^ Schuiling KD, Likis FE (2016). Women's Gynecologic Health . Jones & Bartlett Learning . p. 22. ISBN 978-1-284-12501-6 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13. ^ Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy . SAGE Publications . pp. 18–19. ISBN 978-1-4833-6475-9 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average). ^ Mintz S (1993). "Life stages". Encyclopedia of American Social History . 3 : 7–33. ^ Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?" . Indian Journal of Endocrinology and Metabolism . 18 (Suppl 1): S53-62. doi : 10.4103/2230-8210.145075 . PMC 4266869 . PMID 25538878 . ^ Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?" . Biology of Reproduction . 79 (3): 398–406. doi : 10.1095/biolreprod.108.068536 . PMC 2553520 . PMID 18495681 . ^ Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality . New York: Basic Books. pp. 167–170. ISBN 978-0-465-03127-6 . ^ Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology . 10 (2): 43–57. doi : 10.1002/evan.1013 . S2CID 1665503 . ^ Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth" . USC Trojan Family Magazine . Archived from the original on 13 December 2010 . Retrieved 7 December 2010 . ^ Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex" . Society of Actuaries. Archived from the original on 1 July 2013. ^ "Life expectancy at birth, female (years)" . World Bank . 2018. Archived from the original on 24 January 2021 . Retrieved 13 October 2020 . ^ "Life expectancy at birth, male (years)" . World Bank . 2018. Archived from the original on 24 February 2021 . Retrieved 13 October 2020 . ^ Conceição P, et al. (2019). Human Development Report (PDF) . United Nations Development Programme. ISBN 978-92-1-126439-5 . Archived (PDF) from the original on 20 March 2021 . Retrieved 30 July 2022 . ^ "Human Development Report 2019" (PDF) . United Nations Development Programme . Archived from the original (PDF) on 22 April 2022 . Retrieved 30 July 2022 . ^ "The World Factbook" . U.S. Central Intelligence Agency. Archived from the original on 12 September 2009 . Retrieved 2 April 2005 . ^ "Chapter 1: Setting the Scene" (PDF) . UNFPA. 2012. Archived from the original (PDF) on 12 June 2013 . Retrieved 11 January 2013 . ^ Haenel H (1989). "Phylogenesis and nutrition". Die Nahrung . 33 (9): 867–887. PMID 2697806 . ^ Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable . pp. 264–265. Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods. ^ American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association . 103 (6): 748–765. doi : 10.1053/jada.2003.50142 . PMID 12778049 . ^ Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet" . American Journal of Physical Anthropology . 162 (S63): 84–109. doi : 10.1002/ajpa.23148 . PMID 28105723 . ^ Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century" . The American Journal of Clinical Nutrition . 81 (2): 341–354. doi : 10.1093/ajcn.81.2.341 . PMID 15699220 . ^ Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context" . The Proceedings of the Nutrition Society . 61 (4): 517–526. doi : 10.1079/PNS2002180 . PMID 12691181 . ^ John Carey (2023). "Unearthing the origins of agriculture" . Proceedings of the National Academy of Sciences . 120 (15): e2304407120. Bibcode : 2023PNAS..12004407C . doi : 10.1073/pnas.2304407120 . PMC 10104519 . PMID 37018195 . ^ Ayelet Shavit; Gonen Sharon (2023). "Can models of evolutionary transition clarify the debates over the Neolithic Revolution?" . Philosophical Transactions of the Royal Society B . 378 (1872). doi : 10.1098/rstb.2021.0413 . PMC 9869441 . PMID 36688395 . } ^ Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences" . The American Journal of Clinical Nutrition . 90 (3): 707S–711S. doi : 10.3945/ajcn.2009.27462B . PMID 19656837 . ^ Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology . 69 (5): 605–628. PMID 9299882 . ^ Gibbons A. "The Evolution of Diet" . National Geographic . Archived from the original on 18 August 2014 . Retrieved 18 April 2021 . ^ Ritchie H, Roser M (20 August 2017). "Diet Compositions" . Our World in Data . Archived from the original on 25 August 2021 . Retrieved 30 July 2022 . ^ Lieberson AD (2004). "How Long Can a Person Survive without Food?" . Scientific American . Archived from the original on 14 February 2019 . Retrieved 18 April 2021 . ^ Spector D (9 March 2018). "Here's how many days a person can survive without water" . Business Insider Australia . Archived from the original on 26 June 2014 . Retrieved 18 April 2021 . ^ Holmes J. "Losing 25,000 to Hunger Every Day" . United Nations . Archived from the original on 27 May 2020 . Retrieved 18 April 2021 . ^ Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic" . NPR . Archived from the original on 28 June 2021 . Retrieved 18 April 2021 . ^ Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet . 349 (9063): 1436–1442. doi : 10.1016/S0140-6736(96)07495-8 . PMID 9164317 . S2CID 2569153 . ^ Haslam DW, James WP (October 2005). "Obesity". Lancet . 366 (9492): 1197–1209. doi : 10.1016/S0140-6736(05)67483-1 . PMID 16198769 . S2CID 208791491 . ^ Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine . 30 (3): 415–444, vii. doi : 10.1016/j.ccm.2009.05.001 . PMID 19700042 . ^ de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology . 2 (1): 45–55. doi : 10.1016/j.ehb.2003.11.001 . PMID 15463992 . ^ O'Neil D. "Adapting to Climate Extremes" . Human Biological Adaptability . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status" . PLOS Genetics . 13 (9): e1006977. doi : 10.1371/journal.pgen.1006977 . PMC 5600404 . PMID 28873402 . ^ Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics . 35 (4): 311–313. doi : 10.1038/ng1263 . PMID 14634648 . S2CID 20415396 . ^ Hedrick PW (October 2011). "Population genetics of malaria resistance in humans" . Heredity . 107 (4): 283–304. doi : 10.1038/hdy.2011.16 . PMC 3182497 . PMID 21427751 . ^ Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria" . British Journal of Haematology . 141 (3): 276–286. doi : 10.1111/j.1365-2141.2008.07085.x . PMID 18410566 . S2CID 28191911 . ^ Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea" . Frontiers in Ecology and Evolution . 5 . doi : 10.3389/fevo.2017.00025 . hdl : 11858/00-001M-0000-002C-DD87-4 . ISSN 2296-701X . S2CID 34882477 . ^ Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads" . Cell . 173 (3): 569–580.e15. doi : 10.1016/j.cell.2018.03.054 . PMID 29677510 . ^ Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology . 45 (1): 105–08. doi : 10.1086/381006 . S2CID 224795768 . ^ Roberts D (2011). Fatal Invention . London & New York: The New Press. ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation" . Proceedings of the National Academy of Sciences of the United States of America . 107 (Supplement_2): 8962–8968. Bibcode : 2010PNAS..107.8962J . doi : 10.1073/pnas.0914628107 . PMC 3024016 . PMID 20445093 . ^ Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF) . Journal of Human Evolution . 39 (1): 57–106. doi : 10.1006/jhev.2000.0403 . PMID 10896812 . Archived from the original (PDF) on 14 January 2012. ^ Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R" . American Journal of Human Genetics . 66 (4): 1351–1361. doi : 10.1086/302863 . PMC 1288200 . PMID 10733465 . ^ Robin A (1991). Biological Perspectives on Human Pigmentation . Cambridge: Cambridge University Press. ^ "The Science Behind the Human Genome Project" . Human Genome Project . US Department of Energy. Archived from the original on 2 January 2013 . Retrieved 6 January 2013 . Almost all (99.9%) nucleotide bases are exactly the same in all people. ^ O'Neil D. "Ethnicity and Race: Overview" . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation" . Nature Genetics . 36 (11 Suppl): S17-20. doi : 10.1038/ng1455 . PMID 15507998 . ^ O'Neil D. "Models of Classification" . Modern Human Variation . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Palmié S (May 2007). "Genomics, divination, 'racecraft' ". American Ethnologist . 34 (2): 205–222. doi : 10.1525/ae.2007.34.2.205 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations. ^ Goodman A. "Interview with Alan Goodman" . Race Power of and Illusion . PBS. Archived from the original on 29 October 2012 . Retrieved 6 January 2013 . ^ Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF) . New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012 . Retrieved 5 September 2013 . ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo ^ O'Neil D. "Overview" . Modern Human Variation . Palomar College. Archived from the original on 5 November 2012 . Retrieved 6 January 2013 . ^ Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" . American Journal of Human Genetics . 66 (3): 979–988. doi : 10.1086/302825 . PMC 1288178 . PMID 10712212 . ^ "New Research Proves Single Origin Of Humans In Africa" . Science Daily . 19 July 2007. Archived from the original on 4 November 2011 . Retrieved 5 September 2011 . ^ Manica A, Amos W, Balloux F , Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation" . Nature . 448 (7151): 346–348. Bibcode : 2007Natur.448..346M . doi : 10.1038/nature05951 . PMC 1978547 . PMID 17637668 . ^ Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals" . Cell . 180 (4): 677–687.e16. doi : 10.1016/j.cell.2020.01.012 . PMID 32004458 . S2CID 210955842 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations. ^ Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations" . Science Advances . 6 (7): eaax5097. Bibcode : 2020SciA....6.5097D . doi : 10.1126/sciadv.aax5097 . PMC 7015685 . PMID 32095519 . Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. ^ Pierce BA (2012). Genetics: A Conceptual Approach . Macmillan. p. 75. ISBN 978-1-4292-3252-4 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology . Cambridge University Press. p. 74. ISBN 978-0-521-87948-4 . Retrieved 30 July 2022 . ^ Fusco G, Minelli A (10 October 2019). The Biology of Reproduction . Cambridge University Press. p. 304. ISBN 978-1-108-49985-9 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution . 47 (4): 253–266. doi : 10.1016/j.jhevol.2004.07.004 . PMID 15454336 . ^ Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960–2002" (PDF) . Advance Data (347): 1–17. PMID 15544194 . Archived from the original (PDF) on 23 February 2011. ^ Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology . 66 (3): 254–262. doi : 10.1007/BF00235103 . hdl : 11375/22586 . PMID 8477683 . S2CID 206772211 . ^ Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity . Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi : 10.1007/978-3-319-70178-3_2 . ISBN 978-3-319-70177-6 . PMID 29224088 . ^ Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know" . International Journal of Women's Dermatology . 4 (3): 122–130. doi : 10.1016/j.ijwd.2018.03.002 . PMC 6116811 . PMID 30175213 . ^ Easter C. "Sex Linked" . National Human Genome Research Institute . Archived from the original on 14 April 2022 . Retrieved 18 April 2021 . ^ Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior . 27 (4): 283–296. doi : 10.1016/j.evolhumbehav.2005.11.003 . S2CID 32562654 . ^ "Gender, women, and health" . Reports from WHO 2002–2005 . Archived from the original on 25 June 2013. ^ Sax, Leonard (1 August 2002). "How common is lntersex? A response to Anne Fausto-Sterling" . The Journal of Sex Research . 39 (3): 174–178. doi : 10.1080/00224490209552139 . ISSN 0022-4499 . PMID 12476264 . S2CID 33795209 . ^ "3-D Brain Anatomy" . The Secret Life of the Brain . Public Broadcasting Service. Archived from the original on 5 September 2017 . Retrieved 3 April 2005 . ^ Stern P (22 June 2018). "The human prefrontal cortex is special" . Science . 360 (6395): 1311–1312. Bibcode : 2018Sci...360S1311S . doi : 10.1126/science.360.6395.1311-g . ISSN 0036-8075 . S2CID 149581944 . ^ Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?" . Journal of Intelligence . 2 (3): 119–121. doi : 10.3390/jintelligence2030119 . ISSN 2079-3200 . ^ "Humans not smarter than animals, just different, experts say" . phys.org . Archived from the original on 30 January 2021 . Retrieved 24 October 2020 . ^ Robson D. "We've got human intelligence all wrong" . www.bbc.com . Archived from the original on 31 January 2021 . Retrieved 24 October 2020 . ^ Owen J (26 February 2015). "Many Animals – Including Your Dog – May Have Horrible Short-Term Memories" . National Geographic News . Archived from the original on 19 April 2021 . Retrieved 6 September 2020 . ^ Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research" . American Journal of Physical Anthropology . 116 (S33): 3–24. doi : 10.1002/ajpa.20001 . PMC 2238342 . PMID 11786989 . ^ Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?" . ABC News (American) . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self" . New Scientist . Archived from the original on 18 February 2021 . Retrieved 22 April 2020 . ^ Beck J (2019). "Can We Really Know What Animals Are Thinking?" . Snopes . Archived from the original on 31 October 2021 . Retrieved 22 April 2020 . ^ Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies" . Sleep Medicine Reviews . 14 (4): 239–247. doi : 10.1016/j.smrv.2009.08.001 . PMC 2888649 . PMID 19896872 . ^ Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep" " . Science.howstuffworks.com. Archived from the original on 15 May 2012 . Retrieved 11 August 2012 . ^ Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience . 10 (11): 803–813. doi : 10.1038/nrn2716 . PMID 19794431 . S2CID 205505278 . ^ Empson J (2002). Sleep and dreaming (3rd ed.). New York: Palgrave/St. Martin's Press. ^ Lite J (29 July 2010). "How Can You Control Your Dreams?" . Scientific America . Archived from the original on 2 February 2015. ^ Domhoff W (2002). The scientific study of dreams . APA Press. ^ "Consciousness" . Merriam-Webster . Archived from the original on 7 September 2019 . Retrieved 4 June 2012 . ^ van Gulick R (2004). "Consciousness" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019 . Retrieved 30 July 2022 . ^ Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness . Wiley. ISBN 978-0-470-75145-9 . ^ Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy . Oxford University Press. ISBN 978-0-19-926479-7 . ^ Block N (June 1995). "On a confusion about a function of consciousness" . Behavioral and Brain Sciences . 18 (2): 227–247. doi : 10.1017/S0140525X00038474 . S2CID 246244859 . ^ Jaynes J (2000) [1976]. The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF) . Houghton Mifflin. ISBN 0-618-05707-2 . Archived from the original (PDF) on 7 August 2019 . Retrieved 25 October 2020 . ^ Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition . 12 (4): 717–731. doi : 10.1016/s1053-8100(03)00081-3 . PMID 14656513 . S2CID 10241157 . ^ Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness" . Stanford Encyclopedia of Philosophy . Archived from the original on 13 April 2021 . Retrieved 31 August 2014 . ^ Antony MV (2001). "Is consciousness ambiguous?". Journal of Consciousness Studies . 8 : 19–44. ^ "Cognition" . Lexico . Oxford University Press and Dictionary.com . Archived from the original on 8 July 2016 . Retrieved 6 May 2020 . ^ Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality . The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi : 10.1007/978-3-030-03633-1_14 . ISBN 978-3-030-03633-1 . S2CID 189379814 . ^ "American Psychological Association (2013). Glossary of psychological terms" . Apa.org. Archived from the original on 8 July 2014 . Retrieved 13 August 2014 . ^ "Developmental Psychology Studies Human Development Across the Lifespan" . www.apa.org . Archived from the original on 9 July 2014 . Retrieved 28 August 2017 . ^ Burman E (2017). Deconstructing Developmental Psychology . New York: Routledge. ISBN 978-1-138-84695-1 . ^ Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology : 307–314. doi : 10.1016/B0-12-657410-3/00510-9 . ISBN 978-0-12-657410-4 . ^ McLeod S (20 March 2020). "Maslow's Hierarchy of Needs" . Simplypsychology.org . Simply Scholar Limited. Archived from the original on 8 November 2018 . Retrieved 4 April 2020 . Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up. ^ Heckhausen J, Heckhausen H (28 March 2018). "Motivation and Action: Introduction and Overview". Motivation and Action . Introduction and Overview: Springer, Cham. p. 1. doi : 10.1007/978-3-319-65094-4_1 . ISBN 978-3-319-65093-7 . ^ Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews . 26 (2–3): 83–86. doi : 10.1016/s0165-0173(97)00064-7 . PMID 9651488 . S2CID 8504450 . ^ Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions . New York: Oxford University Press. pp. 291–293. ISBN 978-0-19-508944-8 . Emotional processing, but not emotions, can occur unconsciously. ^ Cabanac M (2002). "What is emotion?". Behavioural Processes . 60 (2): 69–83. doi : 10.1016/S0376-6357(02)00078-5 . PMID 12426062 . S2CID 24365776 . Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure) ^ Scirst DL (2011). Psychology Second Edition . New York: Worth Publishers. p. 310 . ISBN 978-1-4292-3719-2 . ^ Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality . 67 (2): 331–371. doi : 10.1111/1467-6494.00058 . PMID 10202807 . ^ Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory" . Frontiers in Psychology . 8 : 1454. doi : 10.3389/fpsyg.2017.01454 . PMC 5573739 . PMID 28883804 . ^ Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology . Oxford University Press. Archived from the original on 29 January 2021 . Retrieved 30 July 2022 . ^ Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals" . Industrial Psychiatry Journal . 24 (1): 54–58. doi : 10.4103/0972-6748.160934 . PMC 4525433 . PMID 26257484 . ^ Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions" . The American Psychologist . 56 (3): 218–226. doi : 10.1037/0003-066X.56.3.218 . PMC 3122271 . PMID 11315248 . ^ Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica . 90 (3): 387–411. doi : 10.11612/resphil.2013.90.3.5 . ^ Haybron DM (13 April 2014). "Happiness and Its Discontents" . The Opinion Pages . The New York Times. Archived from the original on 12 October 2018 . Retrieved 30 July 2022 . I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life. ^ Graham MC (2014). Facts of Life: ten issues of contentment . Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5 . ^ "Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy" . ScienceDaily . American Psychological Association . 14 August 2017. Archived from the original on 11 November 2020 . Retrieved 25 October 2020 . ^ Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality . Jones & Bartlett Publishers . pp. 4–10. ISBN 978-1-284-08154-1 . Retrieved 21 June 2017 . Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings. ^ Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives . Taylor & Francis . pp. 32–42. ISBN 978-0-7890-2671-2 . ^ Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology . 3 (4): 85–89. doi : 10.1097/01.XHA.0000432482.01760.b0 . S2CID 147235090 . ^ "Sexual orientation, homosexuality and bisexuality" . American Psychological Association . Archived from the original on 8 August 2013 . Retrieved 10 August 2013 . ^ Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science" . Psychological Science in the Public Interest . 17 (2): 45–101. doi : 10.1177/1529100616637616 . PMID 27113562 . ^ LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation . Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6 . Retrieved 30 July 2022 . ^ Balthazart J (2012). The Biology of Homosexuality . Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0 . Retrieved 30 July 2022 . ^ Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York: Basic Books. ISBN 978-0-465-00802-5 . ^ Fromm E (2000). The art of loving . New York: Harper Perennial. ISBN 978-0-06-095828-2 . ^ "Love, Actually: The science behind lust, attraction, and companionship" . Science in the News . 14 February 2017. Archived from the original on 28 October 2020 . Retrieved 25 October 2020 . ^ "What are the top 200 most spoken languages?" . Ethnologue: Languages of the World . 2020. Archived from the original on 12 January 2013 . Retrieved 30 July 2022 . ^ World . The World Factbook (Report). Central Intelligence Agency . Archived from the original on 26 January 2021 . Retrieved 15 November 2021 . ^ "The Changing Global Religious Landscape" . Pew Research Center. 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 30 July 2022 . ^ Ord T (2020). The Precipice: Existential Risk and the Future of Humanity . New York: Hachette Books. ISBN 978-0-316-48489-3 . Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence... ^ Goldman JG (2012). "Pay attention… time for lessons at animal school" . bbc.com . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding" . Science Advances . 4 (11): eaar8334. Bibcode : 2018SciA....4.8334W . doi : 10.1126/sciadv.aar8334 . PMC 6248967 . PMID 30474053 . ^ Johnson-Frey SH (July 2003). "What's so special about human tool use?" . Neuron . 39 (2): 201–204. doi : 10.1016/S0896-6273(03)00424-0 . PMID 12873378 . S2CID 18437970 . ^ Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology . 19 (1): 27–33. doi : 10.1016/j.conb.2009.02.003 . PMID 19328675 . S2CID 18277620 . In short, the evidence to date that animals have an understanding of folk physics is at best mixed. ^ Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To" . National Geographic News . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education" . Procedia - Social and Behavioral Sciences . The Proceedings of 6th World Conference on educational Sciences. 191 : 2565–2567. doi : 10.1016/j.sbspro.2015.04.690 . ISSN 1877-0428 . ^ McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species" . The Guardian . Archived from the original on 5 February 2021 . Retrieved 22 April 2020 . ^ Nicholls H (29 June 2015). "Babblers speak to the origin of language" . The Guardian . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Dasgupta S (2015). "Can any animals talk and use language like humans?" . bbc.com . Archived from the original on 2 May 2020 . Retrieved 22 April 2020 . Most animals are not vocal learners. ^ Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?" . Royal Society. Archived from the original on 18 January 2021 . Retrieved 24 October 2020 . ^ Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?" . BMC Biology . 15 (1): 64. doi : 10.1186/s12915-017-0405-3 . PMC 5525259 . PMID 28738867 . ^ Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist . 208 (2789): ii–iii. Bibcode : 2010NewSc.208D...2F . doi : 10.1016/S0262-4079(10)62961-2 . ISSN 0262-4079 . ^ Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments . London: Palgrave Macmillan UK. pp. 229–255. doi : 10.1057/978-1-137-58746-6_7 . ISBN 978-1-137-58746-6 . ^ "Culture | United Nations For Indigenous Peoples" . www.un.org . 5 June 2015. Archived from the original on 26 November 2020 . Retrieved 24 October 2020 . ^ Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World . New York: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1 . ^ Mavrody S (2013). Visual Art Forms: Traditional to Digital . Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9 . Retrieved 30 July 2022 . ^ "Types of Literary Arts and Their Understanding – bookfestivalscotland.com" . Bookfestival Scotland . 2020. Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ "Bachelor of Performing Arts" (PDF) . University of Otago . Archived (PDF) from the original on 14 December 2021 . Retrieved 30 July 2022 . ^ Brown S (24 October 2018). "Toward a Unification of the Arts" . Frontiers in Psychology . 9 : 1938. doi : 10.3389/fpsyg.2018.01938 . ISSN 1664-1078 . PMC 6207603 . PMID 30405470 . ^ "Culinary arts – How cooking can be an art" . Northern Contemporary Art . 21 October 2019. Archived from the original on 11 May 2021 . Retrieved 5 May 2021 . ^ Smuts A (1 January 2005). "Are Video Games Art?" . Contemporary Aesthetics (Journal Archive) . 3 (1). Archived from the original on 29 May 2022 . Retrieved 30 July 2022 . ^ Cameron IA, Pimlott N (September 2015). "Art of medicine" . Canadian Family Physician . 61 (9): 739–740. PMC 4569099 . PMID 26371092 . ^ Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy . 25 (4): 458–470. doi : 10.1080/10286632.2017.1311328 . ISSN 1028-6632 . S2CID 151443044 . ^ Morriss-Kay GM (February 2010). "The evolution of human artistic creativity" . Journal of Anatomy . 216 (2): 158–176. doi : 10.1111/j.1469-7580.2009.01160.x . PMC 2815939 . PMID 19900185 . ^ Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature . 518 (7538): 228–231. Bibcode : 2015Natur.518..228J . doi : 10.1038/nature13962 . PMID 25470048 . S2CID 4461751 . ^ St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave" . The New York Times . Archived from the original on 14 April 2020 . Retrieved 20 September 2018 . ^ Radford T (16 April 2004). "World's oldest jewellery found in cave" . The Guardian . ISSN 0261-3077 . Archived from the original on 12 February 2021 . Retrieved 23 September 2020 . ^ Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches . Amsterdam: Valiz. pp. 241–263. ^ Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia . 92 (92): 147–177. doi : 10.4436/JASS.92008 (inactive 2024-03-20). PMID 25020016 . {{ cite journal }} : CS1 maint: DOI inactive as of March 2024 ( link ) ^ Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness" (PDF) . NeuroImage . 103 : 55–64. doi : 10.1016/j.neuroimage.2014.09.009 . PMID 25224999 . S2CID 4727529 . ^ Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences . 1337 (1): 140–146. Bibcode : 2015NYASA1337..140K . doi : 10.1111/nyas.12632 . PMID 25773628 . S2CID 206224849 . ^ Chow D (22 March 2010). "Why Do Humans Dance?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 21 September 2020 . ^ Krakauer J (26 September 2008). "Why do we like to dance – And move to the beat?" . Scientific American . Archived from the original on 28 February 2021 . Retrieved 21 September 2020 . ^ Prior KS (21 June 2013). "How Reading Makes Us More Human" . The Atlantic . Archived from the original on 29 January 2021 . Retrieved 23 September 2020 . ^ Puchner M. "How stories have shaped the world" . www.bbc.com . Archived from the original on 5 January 2021 . Retrieved 23 September 2020 . ^ Dalley, Stephanie , ed. (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5 . ^ Hernadi P (2001). "Literature and Evolution" . SubStance . 30 (1/2): 55–71. doi : 10.2307/3685504 . ISSN 0049-2426 . JSTOR 3685504 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run" . The Guardian (U.S. ed.). New York. Archived from the original on 18 June 2022 . Retrieved 30 July 2022 . ^ Clark JD; de Heinzelin J ; Schick KD ; Hart WK; White TD ; WoldeGabriel G; Walter RC; Suwa G ; Asfaw B ; Vrba E ; H.-Selassie Y (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science . 264 (5167): 1907–1910. Bibcode : 1994Sci...264.1907C . doi : 10.1126/science.8009220 . PMID 8009220 . ^ Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use" . livescience.com . Archived from the original on 4 October 2020 . Retrieved 9 October 2020 . ^ Orban GA, Caruana F (2014). "The neural basis of human tool use" . Frontiers in Psychology . 5 : 310. doi : 10.3389/fpsyg.2014.00310 . PMC 3988392 . PMID 24782809 . ^ Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa" . Proceedings of the National Academy of Sciences of the United States of America . 109 (20): E1215-20. doi : 10.1073/pnas.1117620109 . PMC 3356665 . PMID 22474385 . ^ Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1696): 20150164. doi : 10.1098/rstb.2015.0164 . PMC 4874402 . PMID 27216521 . ^ Damiano J (2018). "Neolithic Era Tools: Inventing a New Age" . MagellanTV . Archived from the original on 5 January 2021 . Retrieved 9 October 2020 . ^ Deng Y, Wang P (2011). Ancient Chinese inventions . Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6 . OCLC 671710733 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Schifman J (9 July 2018). "The Entire History of Steel" . Popular Mechanics . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Wilkinson, Freddie (9 January 2020). "Industrial Revolution and Technology" . National Geographic Society . Archived from the original on 30 September 2020 . Retrieved 9 October 2020 . ^ Roser, Max ; Ritchie, Hannah (11 May 2013). "Technological Progress" . Our World in Data . Archived from the original on 10 September 2021 . Retrieved 30 July 2022 . ^ Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel" . The Atlantic . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Idinopulos TA (1998). "What Is Religion?" . CrossCurrents . 48 (3): 366–380. ISSN 0011-1953 . JSTOR 24460821 . Archived from the original on 13 October 2020 . Retrieved 30 July 2022 . ^ Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology . 54 (1): 377–402. doi : 10.1146/annurev.psych.54.101601.145024 . PMID 12171998 . ^ King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?" . The Atlantic . Archived from the original on 20 January 2021 . Retrieved 8 October 2020 . ^ Ball P (2015). "Complex societies evolved without belief in all-powerful deity" . Nature News . doi : 10.1038/nature.2015.17040 . S2CID 183474917 . Archived from the original on 16 May 2021 . Retrieved 30 July 2022 . ^ Culotta E (November 2009). "Origins. On the origin of religion". Science . 326 (5954): 784–787. Bibcode : 2009Sci...326..784C . doi : 10.1126/science.326_784 . PMID 19892955 . ^ Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation" . Evolution and Human Behavior . 32 (1): 41–49. doi : 10.1016/j.evolhumbehav.2010.07.008 . ISSN 1090-5138 . Archived from the original on 15 October 2020 . Retrieved 30 July 2022 . ^ Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA – Journal of Death and Dying . 41 (1): 5–22. doi : 10.2190/Q21C-5VED-GYW6-W091 . ISSN 0030-2228 . S2CID 145686249 . ^ McKay R, Whitehouse H (March 2015). "Religion and morality" . Psychological Bulletin . 141 (2): 447–473. doi : 10.1037/a0038455 . PMC 4345965 . PMID 25528346 . ^ Bernhard Nitsche; Marcus Schmücker, eds. (2023). God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality . De Gruyter . doi : 10.1515/9783110698343 . ISBN 978-3-11-069834-3 . ^ Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique" . Journal of Religion and Health (Submitted manuscript). 47 (2): 134–163. doi : 10.1007/s10943-008-9165-2 . PMC 8823950 . PMID 19105008 . S2CID 25349208 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular" . The Guardian . ISSN 0261-3077 . Archived from the original on 1 March 2021 . Retrieved 8 October 2020 . ^ Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe" . Pew Research Center . Archived from the original on 24 November 2019 . Retrieved 8 October 2020 . ^ "The Changing Global Religious Landscape" . Pew Research Center's Religion & Public Life Project . 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 8 October 2020 . ^ Di Christina, Mariette (September 2018). "A Very Human Story: Why Our Species Is Special" . Scientific American . Archived from the original on 24 November 2020 . Retrieved 27 September 2020 . ^ Andersen H , Hepburn B (2020). "Scientific Method" . In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Lo Presti R (2014). "History of science: The first scientist" . Nature . 512 (7514): 250–251. Bibcode : 2014Natur.512..250L . doi : 10.1038/512250a . ISSN 1476-4687 . S2CID 4394696 . ^ Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn . Springer. p. 1. ISBN 978-3-642-18904-3 . OCLC 883392276 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Needham, J ; Wang Ling (1954). Science and civilisation in China . Cambridge University Press. p. 111. ISBN 0-521-05799-X . OCLC 779676 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6 . OCLC 615209781 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017 . Retrieved 3 July 2017 . ^ Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition . Cambridge University Press. pp. 209–210. ISBN 978-1-107-01116-8 . ^ "Branches of Science" (PDF) . University of Chicago . Archived from the original (PDF) on 23 April 2017 . Retrieved 26 June 2017 . ^ "What is Philosophy?" . Department of Philosophy . Florida State University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ "Philosophy" . Definition, Systems, Fields, Schools, & Biographies . Encyclopedia Britannica. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day" . Philosophy and Phenomenological Research . 7 (3): 461. doi : 10.2307/2102800 . JSTOR 2102800 . Archived from the original on 31 March 2022 . Retrieved 30 July 2022 . ^ Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?" . ieet.org . Archived from the original on 4 March 2021 . Retrieved 8 August 2020 . ^ Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?" . European Journal of Information Systems . 27 (3): 263–277. doi : 10.1080/0960085X.2018.1470776 . hdl : 2086/16128 . ISSN 0960-085X . S2CID 64796132 . ^ Schizzerotto A. "Social Stratification" (PDF) . University of Trento . Archived from the original (PDF) on 20 March 2018 . Retrieved 3 July 2017 . ^ Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution . Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9 . OCLC 1082411117 . ^ "Social Role Theory of Sex Differences and Similarities : A Current Appraisal" . The Developmental Social Psychology of Gender . Psychology Press. 2000. pp. 137–188. doi : 10.4324/9781410605245-12 . ISBN 978-1-4106-0524-5 . Archived from the original on 30 April 2021 . Retrieved 10 June 2022 . ^ Blackstone, Amy (2003). "Gender Roles and Society" . In Miller, Julia R.; Lerner, Richard M.; Schiamberg, Lawrence B. (eds.). Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments . Sociology School Faculty Scholarship. Santa barbara, CA: ABC-CLIO. p. 335. Archived from the original on 16 May 2022 . Retrieved 30 July 2022 . ^ Nadal, Kevin L. (2017). The SAGE Encyclopedia of Psychology and Gender . SAGE Publications. p. 401. ISBN 978-1483384276 . Most cultures currently construct their societies based on the understanding of gender binary – the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization. ^ Herdt, Gilbert (2020). "Third Sexes and Third Genders". Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . Princeton, NJ: Princeton University Press. pp. 21–83. ISBN 978-1-942130-52-9 . Retrieved 30 July 2022 . ^ Trumbach, Randolph (1994). "London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture". In Herdt, Gilbert (ed.). Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . New York: Zone (MIT). pp. 111–136. ISBN 978-0-942299-82-3 . ^ Graham, Sharyn (April–June 2001). "Sulawesi's fifth gender" . Inside Indonesia . Archived from the original on 26 November 2014. ^ Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John ; Nieder, Timo O.; T'Sjoen, Guy (2016). "Non-binary or genderqueer genders" . International Review of Psychiatry . 28 (1): 95–102. doi : 10.3109/09540261.2015.1106446 . hdl : 1854/LU-7279758 . PMID 26753630 . S2CID 29985722 . Archived from the original on 26 June 2019 . Retrieved 9 June 2019 . ^ Ananthaswamy, Anil; Douglas, Kate. "The origins of sexism: How men came to rule 12,000 years ago" . New Scientist . Retrieved 7 March 2023 . ^ "What do we mean by "sex" and "gender"?" . World Health Organization . Archived from the original on 30 January 2017 . Retrieved 26 November 2015 . ^ Alters S, Schiff W (2009). Essential Concepts for Healthy Living . Jones & Bartlett Publishers . p. 143. ISBN 978-0-7637-5641-3 . Retrieved 3 January 2018 . ^ Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy . 21 (3): 416–438. doi : 10.1093/oxrep/gri024 . ^ Dobres, Marcia-Anne (27 November 2020). "Gender in the Earliest Human Societies" . In Meade, Teresa A.; Wiesner-Hanks, Merry E. (eds.). A Companion to Global Gender History (1 ed.). Wiley. pp. 183–204. doi : 10.1002/9781119535812.ch11 . ISBN 978-1-119-53580-5 . S2CID 229399965 . Archived from the original on 10 June 2022 . Retrieved 10 June 2022 . ^ "The Nature of Kinship: Overview" . www2.palomar.edu . Archived from the original on 3 December 2020 . Retrieved 24 October 2020 . ^ Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition" . Proceedings of the National Academy of Sciences of the United States of America . 117 (5): 2378–2384. Bibcode : 2020PNAS..117.2378I . doi : 10.1073/pnas.1917716117 . PMC 7007516 . PMID 31964846 . ^ Chandra, Kanchan (2012). Constructivist theories of ethnic politics . Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7 . OCLC 829678440 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389. In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of 'us' and 'them.' In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population. ^ Blackmore E (22 February 2019). "Race and ethnicity: How are they different?" . Culture . Archived from the original on 22 October 2020 . Retrieved 24 October 2020 . ^ Chandra K (2006). "What is Ethnic Identity and Does It Matter?" . Annual Review of Political Science . 9 (1): 397–424. doi : 10.1146/annurev.polisci.9.062404.170715 . ISSN 1094-2939 . ^ Smith AD (1999). Myths and Memories of the Nation . Oxford University Press. pp. 4–7. ^ Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism . 13 (1): 19–35. doi : 10.1111/j.1469-8129.2007.00271.x . ^ Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism . London: Sage. p. 171. ISBN 978-1-4129-0101-7 . ^ Christian D (2004). Maps of Time . University of California Press. ISBN 978-0-520-24476-4 . ^ Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?" . SAPIENS . Archived from the original on 7 August 2020 . Retrieved 24 October 2020 . ^ Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit" . Proceedings of the National Academy of Sciences of the United States of America . 115 (19): E4532–E4540. Bibcode : 2018PNAS..115E4532Z . doi : 10.1073/pnas.1708960115 . PMC 5948950 . PMID 29674447 . S2CID 4993139 . ^ Melina R (14 February 2011). "What Are the Different Types of Governments?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 24 October 2020 . ^ "Democracy Index 2021: less than half the world lives in a democracy" . The Economist Democracy Index . Economist Intelligence Unit . February 10, 2022. ^ Jeannie Evers (23 December 2012). "international organization" . National Geographic Society . Archived from the original on 27 April 2017 . Retrieved 24 October 2020 . ^ Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization . 58 (1): 1–29. doi : 10.1016/j.jebo.2004.03.009 . ISSN 0167-2681 . ^ Gibbons J (11 August 2015). "Why did Neanderthals go extinct?" . Smithsonian Insider . Archived from the original on 12 November 2020 . Retrieved 11 October 2020 . ^ University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?" . www.newswise.com . Archived from the original on 1 February 2021 . Retrieved 11 October 2020 . ^ Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years" . inews.co.uk . Archived from the original on 23 January 2021 . Retrieved 11 October 2020 . ^ Henriques M. "How spices changed the ancient world" . www.bbc.com . Archived from the original on 25 January 2021 . Retrieved 11 October 2020 . ^ Strauss IE (26 February 2016). "The Myth of the Barter Economy" . The Atlantic . Archived from the original on 15 February 2021 . Retrieved 11 October 2020 . ^ "The History of Money" . www.pbs.org . 26 October 1996. Archived from the original on 29 November 2020 . Retrieved 11 October 2020 . ^ "Why do we need economists and the study of economics?" . Federal Reserve Bank of San Francisco . July 2000. Archived from the original on 12 November 2020 . Retrieved 23 October 2020 . ^ Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong" . New Scientist . Archived from the original on 3 February 2021 . Retrieved 24 October 2020 . ^ Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates" . The Atlantic . Archived from the original on 7 May 2021 . Retrieved 7 May 2021 . ^ Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature . 538 (7624): 233–237. Bibcode : 2016Natur.538..233G . doi : 10.1038/nature19758 . PMID 27680701 . S2CID 4454927 . ^ Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF) . Nature . 538 (7624): 180–181. Bibcode : 2016Natur.538..180P . doi : 10.1038/nature19474 . PMID 27680700 . S2CID 4459560 . Archived (PDF) from the original on 20 May 2022 . Retrieved 30 July 2022 . ^ Ferguson RB (1 September 2018). "War Is Not Part of Human Nature" . Scientific American . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Ferguson N (September–October 2006). "The Next War of the World" . Foreign Affairs . Archived from the original on 25 April 2022 . Retrieved 30 July 2022 . ^ Beauchamp, Zack (June 23, 2015). "600 years of war and peace, in one amazing chart" . Vox . External links Listen to this article ( 1 hour and 16 minutes ) This audio file was created from a revision of this article dated 11 January 2022 ( 2022-01-11 ) , and does not reflect subsequent edits. ( Audio help · More spoken articles ) v t e Human evolution Taxonomy ( Hominins ) Last common ancestors Chimpanzee–human Gorilla–human Orangutan–human Gibbon–human Australopithecines Nakalipithecus Orrorin Sahelanthropus Kenyanthropus Ardipithecus A. kadabba A. ramidus Australopithecus A. afarensis A. africanus A. anamensis A. bahrelghazali A. deyiremeda A. garhi A. sediba Paranthropus P. aethiopicus P. boisei P. robustus Humans and proto-humans ( Homo ) Proto-humans H. gautengensis (?) H. habilis H. naledi H. rudolfensis (?) H. tsaichangensis (?) Homo erectus H. e. erectus H. e. georgicus H. e. lantianensis H. e. nankinensis H. e. pekinensis H. e. soloensis H. e. tautavelensis H. e. yuanmouensis Archaic humans H. antecessor Denisovans H. ergaster (?) H. floresiensis H. heidelbergensis H. longi (?) H. luzonensis H. neanderthalensis H. rhodesiensis (?) Modern humans Homo sapiens H. s. sapiens (archaic homo sapiens, anatomically modern humans) Jebel Irhoud H. s. idaltu Cro-Magnon Manot people Tam Pa Ling Red Deer Cave people Ancestors Homo habilis → Homo ergaster / Homo erectus (→ Homo antecessor ) → Homo heidelbergensis → archaic Homo sapiens → Homo sapiens Models General models Hunting Gathering Endurance running Aquatic ape Sexual selection Self-domestication Specific models Diet Cooking Expensive tissue Shore-based Drugs Drunken monkey Evolutionary models of human drug use Stoned ape theory Behavior Killer ape Cooperative eye Life history Grandmother Patriarch Topics Bipedalism Skeleton Muscles Skin color Hair Thermoregulation Speech Language Intelligence Gender roles Origin of modern humans Recent African origin Multiregional origin Archaic admixture Behavioral modernity Early migrations Recent evolution Timelines Human evolution Human prehistory Human timeline Others Theorists Books Fossils Evolutionary anthropology Paleoanthropology Human evolutionary developmental biology Category Commons Evolutionary biology Portal v t e Extant species of family Hominidae (great apes) Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Hominidae Ponginae Pongo (Orangutans) Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Homininae Gorilla (Gorillas) Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Hominini Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Homo (Humans) Human ( H. sapiens ) Category v t e Apes Extant ape species Homo Human ( H. sapiens ) Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Gorilla Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Orangutan Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Gibbon ( family : Hylobatidae) Study of apes Great ape language Dian Fossey Birutė Galdikas Jane Goodall Chimpanzee genome project Human Genome Project Gladys Kalema-Zikusoka Neanderthal genome project Willie Smits Lone Drøscher Nielsen Ian Redmond Elgin Center Iowa Primate Learning Sanctuary Borneo Orangutan Survival Primate archaeology Legal and social status Personhood Research ban Kinshasa Declaration on Great Apes Great Ape Project Great Apes Survival Partnership International Primate Day Nonhuman Rights Project Related Primate List of individual apes (non-human) Apes in space (non-human) Bigfoot Bushmeat Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor Gibbon–human last common ancestor List of fictional primates (non-human) Great apes Human evolution Monkey Day Mythic humanoids Yeren Yeti Yowie Category Humans at Wikipedia's sister projects : Definitions from Wiktionary Media from Commons Quotations from Wikiquote Texts from Wikisource Taxa from Wikispecies Taxon identifiers Homo sapiens Wikidata : Q15978631 ADW : Homo_sapiens BOLD : 12439 CoL : 6MB3T EoL : 327955 EPPO : HOMXSA GBIF : 2436436 iNaturalist : 43584 IRMNG : 10857762 ITIS : 180092 MDD : 1000718 MSW : 12100795 NBN : NHMSYS0000376773 NCBI : 9606 NZOR: d83185ac-1aa6-4f59-8645-fe8c040857b3 Observation.org : 83981 OBIS : 1455977 Open Tree of Life : 770315 Paleobiology Database : 83088 TSA : 8319 WoRMS : 1455977 ZooBank : 58D31D52-713D-44B4-9FE9-CB2D9249C422 Authority control databases International FAST National France BnF data Germany Israel Czech Republic Korea Other Encyclopedia of Modern Ukraine NARA İslâm Ansiklopedisi Retrieved from " https://en.wikipedia.org/w/index.php?title=Human&oldid=1221314650 " Categories : Hominini Humans Apex predators Mammals described in 1758 Taxa named by Carl Linnaeus Tool-using mammals Cosmopolitan mammals Hidden categories: CS1 maint: DOI inactive as of March 2024 Articles with short description Short description is different from Wikidata Good articles Wikipedia indefinitely semi-protected pages Wikipedia indefinitely move-protected pages Articles with 'species' microformats Articles containing Latin-language text Articles containing Old French (842-ca. 1400)-language text Articles containing French-language text Articles containing potentially dated statements from 2018 All articles containing potentially dated statements Articles with hAudio microformats Spoken articles Pages using Sister project links with wikidata mismatch Pages using Sister project links with default search Taxonbars desynced from Wikidata Taxonbars on possible non-taxon pages Taxonbars with 20–24 taxon IDs Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with GND identifiers Articles with J9U identifiers Articles with NKC identifiers Articles with NLK identifiers Articles with EMU identifiers Articles with NARA identifiers Articles with TDVİA identifiers Articles containing video clips
213 languages Afrikaans Alemannisch አማርኛ अंगिका العربية Aragonés ܐܪܡܝܐ Armãneashti অসমীয়া Asturianu Atikamekw अवधी Avañe'ẽ Авар Aymar aru Azərbaycanca تۆرکجه Basa Bali বাংলা Banjar 閩南語 / Bân-lâm-gú Basa Banyumasan Башҡортса Беларуская Беларуская (тарашкевіца) भोजपुरी Bikol Central Български Boarisch བོད་ཡིག Bosanski Brezhoneg Буряад Català Чӑвашла Cebuano Čeština ChiShona ChiTumbuka Corsu Cymraeg Dagbanli Dansk الدارجة Davvisámegiella Deutsch डोटेली Eesti Ελληνικά Эрзянь Español Esperanto Euskara فارسی Fiji Hindi Føroyskt Frysk Furlan Gaeilge Gàidhlig Galego ГӀалгӀай 贛語 گیلکی ગુજરાતી 客家語/Hak-kâ-ngî 한국어 Hausa Հայերեն हिन्दी Hrvatski Ido Igbo Ilokano Bahasa Indonesia ᐃᓄᒃᑎᑐᑦ / inuktitut Ирон IsiXhosa IsiZulu Íslenska עברית Jawa ಕನ್ನಡ Kapampangan ქართული कॉशुर / کٲشُر Қазақша Kernowek Kiswahili Коми Kongo Kreyòl ayisyen Kriyòl gwiyannen Kurdî Кыргызча Ladin Лакку ລາວ Latgaļu Latina Latviešu Лезги Lietuvių Ligure Limburgs Lingála Lingua Franca Nova La .lojban. Luganda Magyar मैथिली Македонски Malagasy മലയാളം Malti मराठी მარგალური مصرى مازِرونی Bahasa Melayu ꯃꯤꯇꯩ ꯂꯣꯟ Minangkabau 閩東語 / Mìng-dĕ̤ng-ngṳ̄ Mirandés Мокшень Монгол မြန်မာဘာသာ Nāhuatl Nederlands Nedersaksies नेपाली नेपाल भाषा 日本語 Нохчийн Nordfriisk Norfuk / Pitkern Norsk bokmål Norsk nynorsk Occitan Олык марий ଓଡ଼ିଆ Oʻzbekcha / ўзбекча ਪੰਜਾਬੀ पालि پنجابی Papiamentu پښتو Patois Перем коми ភាសាខ្មែរ Piemontèis Plattdüütsch Polski Português Qaraqalpaqsha Ripoarisch Română Romani čhib Rumantsch Runa Simi Русский Саха тыла Sakizaya संस्कृतम् ᱥᱟᱱᱛᱟᱲᱤ Scots Shqip Sicilianu සිංහල Simple English سنڌي Slovenčina Slovenščina Ślůnski Soomaaliga کوردی Српски / srpski Srpskohrvatski / српскохрватски Sunda Suomi Svenska Tagalog தமிழ் Taclḥit Taqbaylit Татарча / tatarça Tayal తెలుగు ไทย Тоҷикӣ Türkçe Türkmençe Twi Tyap Українська اردو ئۇيغۇرچە / Uyghurche Vahcuengh Vepsän kel’ Tiếng Việt Võro Walon 文言 West-Vlams Winaray 吴语 Xitsonga ייִדיש Yorùbá 粵語 Zazaki Žemaitėška 中文 Edit links
Afrikaans Alemannisch አማርኛ अंगिका العربية Aragonés ܐܪܡܝܐ Armãneashti অসমীয়া Asturianu Atikamekw अवधी Avañe'ẽ Авар Aymar aru Azərbaycanca تۆرکجه Basa Bali বাংলা Banjar 閩南語 / Bân-lâm-gú Basa Banyumasan Башҡортса Беларуская Беларуская (тарашкевіца) भोजपुरी Bikol Central Български Boarisch བོད་ཡིག Bosanski Brezhoneg Буряад Català Чӑвашла Cebuano Čeština ChiShona ChiTumbuka Corsu Cymraeg Dagbanli Dansk الدارجة Davvisámegiella Deutsch डोटेली Eesti Ελληνικά Эрзянь Español Esperanto Euskara فارسی Fiji Hindi Føroyskt Frysk Furlan Gaeilge Gàidhlig Galego ГӀалгӀай 贛語 گیلکی ગુજરાતી 客家語/Hak-kâ-ngî 한국어 Hausa Հայերեն हिन्दी Hrvatski Ido Igbo Ilokano Bahasa Indonesia ᐃᓄᒃᑎᑐᑦ / inuktitut Ирон IsiXhosa IsiZulu Íslenska עברית Jawa ಕನ್ನಡ Kapampangan ქართული कॉशुर / کٲشُر Қазақша Kernowek Kiswahili Коми Kongo Kreyòl ayisyen Kriyòl gwiyannen Kurdî Кыргызча Ladin Лакку ລາວ Latgaļu Latina Latviešu Лезги Lietuvių Ligure Limburgs Lingála Lingua Franca Nova La .lojban. Luganda Magyar मैथिली Македонски Malagasy മലയാളം Malti मराठी მარგალური مصرى مازِرونی Bahasa Melayu ꯃꯤꯇꯩ ꯂꯣꯟ Minangkabau 閩東語 / Mìng-dĕ̤ng-ngṳ̄ Mirandés Мокшень Монгол မြန်မာဘာသာ Nāhuatl Nederlands Nedersaksies नेपाली नेपाल भाषा 日本語 Нохчийн Nordfriisk Norfuk / Pitkern Norsk bokmål Norsk nynorsk Occitan Олык марий ଓଡ଼ିଆ Oʻzbekcha / ўзбекча ਪੰਜਾਬੀ पालि پنجابی Papiamentu پښتو Patois Перем коми ភាសាខ្មែរ Piemontèis Plattdüütsch Polski Português Qaraqalpaqsha Ripoarisch Română Romani čhib Rumantsch Runa Simi Русский Саха тыла Sakizaya संस्कृतम् ᱥᱟᱱᱛᱟᱲᱤ Scots Shqip Sicilianu සිංහල Simple English سنڌي Slovenčina Slovenščina Ślůnski Soomaaliga کوردی Српски / srpski Srpskohrvatski / српскохрватски Sunda Suomi Svenska Tagalog தமிழ் Taclḥit Taqbaylit Татарча / tatarça Tayal తెలుగు ไทย Тоҷикӣ Türkçe Türkmençe Twi Tyap Українська اردو ئۇيغۇرچە / Uyghurche Vahcuengh Vepsän kel’ Tiếng Việt Võro Walon 文言 West-Vlams Winaray 吴语 Xitsonga ייִדיש Yorùbá 粵語 Zazaki Žemaitėška 中文 Edit links
Afrikaans Alemannisch አማርኛ अंगिका العربية Aragonés ܐܪܡܝܐ Armãneashti অসমীয়া Asturianu Atikamekw अवधी Avañe'ẽ Авар Aymar aru Azərbaycanca تۆرکجه Basa Bali বাংলা Banjar 閩南語 / Bân-lâm-gú Basa Banyumasan Башҡортса Беларуская Беларуская (тарашкевіца) भोजपुरी Bikol Central Български Boarisch བོད་ཡིག Bosanski Brezhoneg Буряад Català Чӑвашла Cebuano Čeština ChiShona ChiTumbuka Corsu Cymraeg Dagbanli Dansk الدارجة Davvisámegiella Deutsch डोटेली Eesti Ελληνικά Эрзянь Español Esperanto Euskara فارسی Fiji Hindi Føroyskt Frysk Furlan Gaeilge Gàidhlig Galego ГӀалгӀай 贛語 گیلکی ગુજરાતી 客家語/Hak-kâ-ngî 한국어 Hausa Հայերեն हिन्दी Hrvatski Ido Igbo Ilokano Bahasa Indonesia ᐃᓄᒃᑎᑐᑦ / inuktitut Ирон IsiXhosa IsiZulu Íslenska עברית Jawa ಕನ್ನಡ Kapampangan ქართული कॉशुर / کٲشُر Қазақша Kernowek Kiswahili Коми Kongo Kreyòl ayisyen Kriyòl gwiyannen Kurdî Кыргызча Ladin Лакку ລາວ Latgaļu Latina Latviešu Лезги Lietuvių Ligure Limburgs Lingála Lingua Franca Nova La .lojban. Luganda Magyar मैथिली Македонски Malagasy മലയാളം Malti मराठी მარგალური مصرى مازِرونی Bahasa Melayu ꯃꯤꯇꯩ ꯂꯣꯟ Minangkabau 閩東語 / Mìng-dĕ̤ng-ngṳ̄ Mirandés Мокшень Монгол မြန်မာဘာသာ Nāhuatl Nederlands Nedersaksies नेपाली नेपाल भाषा 日本語 Нохчийн Nordfriisk Norfuk / Pitkern Norsk bokmål Norsk nynorsk Occitan Олык марий ଓଡ଼ିଆ Oʻzbekcha / ўзбекча ਪੰਜਾਬੀ पालि پنجابی Papiamentu پښتو Patois Перем коми ភាសាខ្មែរ Piemontèis Plattdüütsch Polski Português Qaraqalpaqsha Ripoarisch Română Romani čhib Rumantsch Runa Simi Русский Саха тыла Sakizaya संस्कृतम् ᱥᱟᱱᱛᱟᱲᱤ Scots Shqip Sicilianu සිංහල Simple English سنڌي Slovenčina Slovenščina Ślůnski Soomaaliga کوردی Српски / srpski Srpskohrvatski / српскохрватски Sunda Suomi Svenska Tagalog தமிழ் Taclḥit Taqbaylit Татарча / tatarça Tayal తెలుగు ไทย Тоҷикӣ Türkçe Türkmençe Twi Tyap Українська اردو ئۇيغۇرچە / Uyghurche Vahcuengh Vepsän kel’ Tiếng Việt Võro Walon 文言 West-Vlams Winaray 吴语 Xitsonga ייִדיש Yorùbá 粵語 Zazaki Žemaitėška 中文 Edit links
Article Talk English Read View source View history Tools Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote
Article Talk English Read View source View history Tools Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote
Read View source View history Tools Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote
Tools Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote
Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote
Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote
Tools move to sidebar hide Actions Read View source View history General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item Print/export Download as PDF Printable version In other projects Wikimedia Commons Wikispecies Wikiquote
General What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item
What links here Related changes Upload file Special pages Permanent link Page information Cite this page Get shortened URL Download QR code Wikidata item
From Wikipedia, the free encyclopedia Species of hominid in the genus Homo Several terms redirect here. For other uses, see Human (disambiguation) , Mankind (disambiguation) , Humankind (disambiguation) , Human Race (disambiguation) , Human Being (disambiguation) , and Homo sapiens (disambiguation) . Human Temporal range: 0.3–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Chibanian – present Male (left) and female (right) adult humans, Thailand , 2007 Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Infraorder: Simiiformes Family: Hominidae Subfamily: Homininae Tribe: Hominini Genus: Homo Species: H. sapiens Binomial name Homo sapiens Linnaeus , 1758 Homo sapiens population density (2005) Humans ( Homo sapiens ) or modern humans are the most common and widespread species of primate , and the last surviving species of the genus Homo . They are great apes characterized by their hairlessness , bipedalism , and high intelligence . Humans have large brains , enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools , and form complex social structures and civilizations . Humans are highly social , with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states . As such, social interactions between humans have established a wide variety of values, social norms , languages , and traditions (collectively termed institutions ), each of which bolsters human society . Humans are also highly curious : the desire to understand and influence phenomena has motivated humanity's development of science , technology , philosophy , mythology , religion , and other frameworks of knowledge ; humans also study themselves through such domains as anthropology , social science , history , psychology , and medicine . As of April 2024, there are estimated to be more than 8 billion humans alive . Although some scientists equate the term "humans" with all members of the genus Homo , in common usage it generally refers to Homo sapiens , the only extant member. All other members of the genus Homo , which are now extinct, are known as archaic humans , and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa , they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence , interbreeding with Homo sapiens , or inability to adapt to climate change. For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution , which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement ; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change . Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle. Genes and the environment influence human biological variation in visible characteristics, physiology , disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic : generally, males have greater body strength and females have a higher body fat percentage. At puberty , humans develop secondary sex characteristics . Females are capable of pregnancy , usually between puberty, at around 12 years old, and menopause , around the age of 50. Humans are omnivorous , capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus . Humans can survive for up to eight weeks without food and several days without water . Humans are generally diurnal , sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death . Often, both the mother and the father provide care for their children, who are helpless at birth . Humans have a large, highly developed, and complex prefrontal cortex , the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory ; they have flexible facial expressions, self-awareness , and a theory of mind . The human mind is capable of introspection , private thought , imagination , volition , and forming views on existence . This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language . Etymology and definition Further information: Names for the human species and Human taxonomy Carl Linnaeus coined the name Homo sapiens All modern humans are classified into the species Homo sapiens , coined by Carl Linnaeus in his 1735 work Systema Naturae . The generic name " Homo " is a learned 18th-century derivation from Latin homō , which refers to humans of either sex. The word human can refer to all members of the Homo genus. The name " Homo sapiens " means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals , should be included as a separate species of humans or as a subspecies of H. sapiens . Human is a loanword of Middle English from Old French humain , ultimately from Latin hūmānus , the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity ) as well as to human males. It may also refer to individuals of either sex. Despite the fact that the word animal is colloquially used as an antonym for human , and contrary to a common biological misconception , humans are animals. The word person is often used interchangeably with human , but philosophical debate exists as to whether personhood applies to all humans or all sentient beings , and further if one can lose personhood (such as by going into a persistent vegetative state ). Evolution Main article: Human evolution Humans are apes ( superfamily Hominoidea ). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo ), then gorillas (genus Gorilla ), and finally, chimpanzees and bonobos (genus Pan ). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct. Reconstruction of Lucy , the first Australopithecus afarensis skeleton found The genus Homo evolved from Australopithecus . Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus . The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia , and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster ) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan . Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis , the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier. The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second ( Southern Dispersal ) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii , Easter Island , Madagascar , and New Zealand in the years 300 to 1280 CE. Human evolution was not a simple linear or branched progression but involved interbreeding between related species . Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans , may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans. Human evolution is characterized by a number of morphological , developmental , physiological , and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees . The most significant of these adaptations are hairlessness , obligate bipedalism, increased brain size and decreased sexual dimorphism ( neoteny ). The relationship between all these changes is the subject of ongoing debate. Hominoidea (hominoids, apes ) Hylobatidae ( gibbons ) Hominidae (hominids, great apes ) Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans) History Main article: Human history Prehistory Main article: Prehistory Overview map of the peopling of the world by early human migration during the Upper Paleolithic , following the Southern Dispersal paradigm Until about 12,000 years ago, all humans lived as hunter-gatherers . The Neolithic Revolution (the invention of agriculture ) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea , and the Sahel and West Savanna regions of Africa. Access to food surplus led to the formation of permanent human settlements , the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations . Ancient Main article: Ancient history Great Pyramids of Giza , Egypt An urban revolution took place in the 4th millennium BCE with the development of city-states , particularly Sumerian cities located in Mesopotamia . It was in these cities that the earliest known form of writing, cuneiform script , appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation . They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture , Minoans and the Shang dynasty , rose to prominence in new areas. The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages . During this period iron started replacing bronze, leading to the Iron Age . In the 5th century BCE, history started being recorded as a discipline , which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars . In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire 's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions. Medieval Main article: Post-classical history Medieval French manuscript illustration of the three classes of medieval society from the 13th-century Li Livres dou Santé Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages . During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age , inspiring achievements in architecture , the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England , the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims . In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast . Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific. Modern Main articles: Early modern period and Late modern period James Watt 's steam engine The early modern period in Europe and the Near East ( c. 1450 –1800) began with the final defeat of the Byzantine Empire , and the rise of the Ottoman Empire . Meanwhile, Japan entered the Edo period , the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance , starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas . This expansion led to the Atlantic slave trade and the genocide of Native American peoples . This period also marked the Scientific Revolution , with great advances in mathematics , mechanics , astronomy and physiology . The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology , major innovations in transport and energy development . The United States of America underwent great change, going from a small group of colonies to one of the global superpowers . The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World , while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania. A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War , one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War , involving almost all of the world's countries . The war's destruction led to the collapse of most global empires, leading to widespread decolonization. Contemporary Main article: Contemporary history Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race , ending in the collapse of the Soviet Union. The current Information Age , spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected. Habitat and population Further information: Human geography and Demography Population statistics Choropleth showing Population density (people per square kilometer) estimates by 30 arc-second grid in 2020 World population 8.1 billion Population density 16/km (41/sq mi) by total area 54/km (140/sq mi) by land area Largest cities Tokyo , Delhi , Shanghai , São Paulo , Mexico City , Cairo , Mumbai , Beijing , Dhaka , Osaka , New York - Newark , Karachi , Buenos Aires , Chongqing , Istanbul , Kolkata , Manila , Lagos , Rio de Janeiro , Tianjin , Kinshasa , Guangzhou , Los Angeles - Long Beach - Santa Ana , Moscow , Shenzhen , Lahore , Bangalore , Paris , Jakarta , Chennai , Lima , Bogota , Bangkok , London Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence , such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation , urban planning , construction, deforestation and desertification . Human settlements continue to be vulnerable to natural disasters , especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics , increasing knowledge or enhancing the exchange of resources. Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms , although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa , India , Russia , Australia , Fiji , United States and Brazil (each located in a different biogeographical realm). By using advanced tools and clothing , humans have been able to extend their tolerance to a wide variety of temperatures, humidities , and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest , arid desert , extremely cold arctic regions , and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth 's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%). Within the last century, humans have explored challenging environments such as Antarctica, the deep sea , and outer space . Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific , military , or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft . Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station . Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%. Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues , first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals. In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums . Humans have had a dramatic effect on the environment . They are apex predators , being rarely preyed upon by other species. Human population growth , industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life. Biology Anatomy and physiology Main article: Human body Basic anatomical features of female and male humans. These models have had body hair and male facial hair removed and head hair trimmed. Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.3 2.1.2.3 . Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth . Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars , with some individuals having them congenitally absent. Humans share with chimpanzees a vestigial tail, appendix , flexible shoulder joints, grasping fingers and opposable thumbs . Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling , hearing and digesting proteins . While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair , most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet. It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged . Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals. Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger. Genetics Main article: Human genetics A graphical representation of the standard human karyotype , including both the female (XX) and male (XY) sex chromosomes. Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes , each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes . Like other mammals, humans have an XY sex-determination system , so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood. While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years. The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms . African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas . By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA , which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve , must have lived around 90,000 to 200,000 years ago. Life cycle See also: Childbirth and Life expectancy A 10 mm human embryo at 5 weeks Most human reproduction takes place by internal fertilization via sexual intercourse , but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus . Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions. Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries. Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth , humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy , childhood , adolescence , adulthood and old age . The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis ), rather than by continuing to bear children into old age. The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018 , the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic , it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world , the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide. Human life stages Infant boy and girl Boy and girl before puberty ( children ) Adolescent male and female Adult man and woman Elderly man and woman Diet Main article: Human nutrition Humans living in Bali , Indonesia , preparing a meal Humans are omnivorous , capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous . In some cases, dietary restrictions in humans can lead to deficiency diseases ; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science . Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game , which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus . Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture , a gradual process called the Neolithic Revolution . These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture. In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation . Childhood malnutrition is also common and contributes to the global burden of disease . However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries . Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an " obesity epidemic ." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet. Biological variation Main article: Human genetic variation A Libyan , a Nubian , a Syrian , and an Egyptian , drawing by an unknown artist after a mural of the tomb of Seti I There is biological variation in the human species – with traits such as blood type , genetic diseases , cranial features , facial features , organ systems , eye color , hair color and texture , height and build , and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin , and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet , exercise, and sleep patterns . A variety of human hair colors; from top left, clockwise: black , brown , blonde , white , red . There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk . Sickle cell anemia , which may provide increased resistance to malaria , is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions , tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes . Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau . Human hair ranges in color from red to blond to brown to black , which is the most frequent. Hair color depends on the amount of melanin , with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach , or even nearly white or colorless in cases of albinism . It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D , which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation. There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other. Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa , and particularly West Africa , have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans. Humans are a gonochoric species, meaning they are divided into male and female sexes . The greatest degree of genetic variation exists between males and females . While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation . As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare. Psychology Main article: Psychology Drawing of the human brain , showing several important structures The human brain , the focal point of the central nervous system in humans, controls the peripheral nervous system . In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion , it is also the locus of "higher" order functioning such as thought , reasoning , and abstraction . These cognitive processes constitute the mind , and, along with their behavioral consequences, are studied in the field of psychology . Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition . This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to. There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in " mental time travel ". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind . Sleep and dreaming Main articles: Sleep and Dream Humans are generally diurnal . The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort. During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep . The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming , where the dreamer is self-aware . Dreams can at times make a creative thought occur or give a sense of inspiration . Consciousness and thought Main articles: Consciousness and Cognition Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection , private thought , imagination and volition . It now often includes some kind of experience , cognition , feeling or perception . It may be 'awareness', or ' awareness of awareness ', or self-awareness . There might be different levels or orders of consciousness , or different kinds of consciousness, or just one kind with different features. The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses , and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition , the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development . Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population. Motivation and emotion Main articles: Motivation and Emotion Illustration of grief from Charles Darwin 's 1872 book The Expression of the Emotions in Man and Animals Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization . Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure . They are often intertwined with mood , temperament , personality , disposition , creativity , and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal. Emotional experiences perceived as pleasant , such as joy , interest or contentment , contrast with those perceived as unpleasant , like anxiety , sadness , anger , and despair . Happiness , or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects , while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life . Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted. Sexuality and love Main articles: Human sexuality and Love Human parents often display familial love for their children. For humans, sexuality involves biological , erotic , physical , emotional , social , or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions , including the human sexual response cycle . Sexuality also affects and is affected by cultural, political, legal, philosophical, moral , ethical , and religious aspects of life. Sexual desire, or libido , is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often. Humans can fall anywhere along a continuous scale of sexual orientation , although most humans are heterosexual . While homosexual behavior occurs in some other animals , only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation , as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well. Love most commonly refers to a feeling of strong attraction or emotional attachment . It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine , norepinephrine , serotonin and other chemicals stimulate the brain's pleasure center , leading to side effects such as increased heart rate , loss of appetite and sleep , and an intense feeling of excitement . Culture Main articles: Culture and Cultural universal Human society statistics Most widely spoken languages English , Mandarin Chinese , Hindi , Spanish , Standard Arabic , Bengali , French , Russian , Portuguese , Urdu Most practiced religions Christianity , Islam , Hinduism , Buddhism , folk religions , Sikhism , Judaism , unaffiliated Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the " folk physics " required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning . Language Main article: Language Principal language families of the world (and in some cases geographic groups of families). For greater detail, see Distribution of languages in the world . While many species communicate , language is unique to humans, a defining feature of humanity, and a cultural universal . Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement , using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors. Language differs from other forms of communication in that it is modality independent ; the same meanings can be conveyed through different media, audibly in speech , visually by sign language or writing, and through tactile media such as braille . Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct . The arts Main article: The arts Human arts can take many forms including visual , literary , and performing . Visual art can range from paintings and sculptures to film , fashion design , and architecture . Literary arts can include prose , poetry , and dramas . The performing arts generally involve theatre , music , and dance . Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation , video games , and medicine . As well as providing entertainment and transferring knowledge, the arts are also used for political purposes . The Deluge tablet of the Gilgamesh epic in Akkadian Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage. Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures . There exists a wide variety of music genres and ethnic musics ; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment . Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain. Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh , first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation. Tools and technologies Main articles: Tool and Technology The SCMaglev , the fastest train in the world clocking in at 603 km/h (375 mph) as of 2015 Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated , thus proving essential in the development of agriculture – what is known as the Neolithic Revolution . China developed paper , the printing press , gunpowder , the compass and other important inventions . The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel , which is used in railways , skyscrapers and many other products. This coincided with the Industrial Revolution , where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially , with major innovations in the 20th century including: electricity , penicillin , semiconductors , internal combustion engines , the Internet , nitrogen fixing fertilisers , airplanes , computers , automobiles , contraceptive pills , nuclear fission , the green revolution , radio , scientific plant breeding , rockets , air conditioning , television and the assembly line . Religion and spirituality Main articles: Religion and Spirituality Shango , the Orisha of fire, lightning, and thunder, in the Yoruba religion , depicted on horseback Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural , sacred or divine , and practices, values , institutions and rituals associated with such belief. Some religions also have a moral code . The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago ). It may have evolved to play a role in helping enforce and encourage cooperation between humans. Religion manifests in diverse forms. Religion can include a belief in life after death , the origin of life , the nature of the universe ( religious cosmology ) and its ultimate fate ( eschatology ), and moral or ethical teachings . Views on transcendence and immanence vary substantially; traditions variously espouse monism , deism , pantheism , and theism (including polytheism and monotheism ). Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims , Hindus and Buddhists . As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious , including those with no religious beliefs or no identity with any religion. Science and philosophy Main articles: Science and Philosophy The Dunhuang map , a star map showing the North Polar region. China circa 700. An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy. Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period . Other early advances in science came from the Han dynasty in China and during the Islamic Golden Age . The scientific revolution , near the end of the Renaissance , led to the emergence of modern science . A chain of events and influences led to the development of the scientific method , a process of observation and experimentation that is used to differentiate science from pseudoscience . An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition . All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics ), which are concerned with formal systems , the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics , chemistry , biology ) and social sciences (e.g., psychology , economics, sociology). Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics , epistemology , logic , and axiology (which includes ethics and aesthetics ). Society Main article: Society Humans often live in family-based social structures Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power , reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies . Gender Main article: Gender Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex . The most common categorisation is a gender binary of men and women . Some societies recognise a third gender , or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female. Gender roles are often associated with a division of norms , practices , dress , behavior , rights , duties , privileges , status , and power , with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct , gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic , while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal. Kinship Main article: Kinship All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants ( consanguinity ), and relations through marriage ( affinity ). There is also a third type applied to godparents or adoptive children ( fictive ). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance . All societies have rules of incest taboo , according to which marriage between certain kinds of kin relations is prohibited, and some also have rules of preferential marriage with certain kin relations. Ethnicity Main article: Ethnic group Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry , language , history , society , culture , nation , religion , or social treatment within their residing area. Ethnicity is separate from the concept of race , which is based on physical characteristics, although both are socially constructed . Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries. Government and politics Main articles: Government and Politics The United Nations headquarters in New York City, which houses one of the world's largest political organizations As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances. Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy , 17% in a hybrid regime , and 37% in an authoritarian regime . Many countries belong to international organizations and alliances ; the largest of these is the United Nations , with 193 member states . Trade and economics Main articles: Trade and Economics The Silk Road (red) and spice trade routes (blue) Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian . The first truly international trade routes were around the spice trade through the Roman and medieval periods. Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities ; the oldest being in the form of cattle and the most widely used being cowrie shells . Money has since evolved into governmental issued coins , paper and electronic money . Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population. Conflict Main article: Conflict (process) American troops landing at Normandy , WWII. Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered , rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations, with rates of homicide about 0.01% in societies that have legal systems and strong cultural attitudes against violence. The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war ) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict. See also Mammals portal Evolutionary biology portal Science portal List of human evolution fossils Timeline of human evolution Notes ^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects. ^ Cities with over 10 million inhabitants as of 2018. ^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that. References ^ Groves CP (2005). Wilson DE , Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4 . OCLC 62265494 . ^ Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences . 149 (1): 109–114. JSTOR 4065043 . ^ Porkorny (1959). IEW . s.v. "g'hðem" pp. 414–116. ^ "Homo" . Dictionary.com Unabridged (v 1.1) . Random House. 23 September 2008. Archived from the original on 27 September 2008. ^ Barras, Colin (11 January 2016). "We don't know which species should be classed as 'human' " . BBC . Archived from the original on 26 August 2021 . Retrieved 31 March 2021 . ^ Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758" . Proceedings of the Academy of Natural Sciences of Philadelphia . 149 : 109–114. ISSN 0097-3157 . JSTOR 4065043 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . ^ OED . s.v. "human". ^ "Man" . Merriam-Webster Dictionary . Archived from the original on 22 September 2017 . Retrieved 14 September 2017 . Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination ^ "Thesaurus results for human" . Merriam-Webster Dictionary . Archived from the original on 28 June 2022 . Retrieved 21 May 2022 . ^ "Misconceptions about evolution – Understanding Evolution" . University of California, Berkeley . 19 September 2021. Archived from the original on 6 June 2022 . Retrieved 21 May 2022 . ^ "Concept of Personhood" . University of Missouri School of Medicine . Archived from the original on 4 March 2021 . Retrieved 4 July 2021 . ^ Tuttle RH (4 October 2018). "Hominoidea: conceptual history" . In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology . Hoboken , New Jersey , United States : John Wiley & Sons, Inc. pp. 1–2. doi : 10.1002/9781118584538.ieba0246 . ISBN 978-1-118-58442-2 . S2CID 240125199 . Retrieved 26 May 2021 . ^ Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution . 30 (3): 260–266. Bibcode : 1990JMolE..30..260G . doi : 10.1007/BF02099995 . PMID 2109087 . S2CID 2112935 . ^ Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets" . Molecular Biology and Evolution . 14 (3): 248–265. doi : 10.1093/oxfordjournals.molbev.a025761 . PMID 9066793 . ^ MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes" . Evolution pages . Archived from the original on 9 August 2011 . Retrieved 18 May 2006 . ^ McNulty, Kieran P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?" . Nature Education Knowledge . Archived from the original on 10 January 2016 . Retrieved 11 June 2022 . ^ Strait DS (September 2010). "The Evolutionary History of the Australopiths" . Evolution: Education and Outreach . 3 (3): 341–352. doi : 10.1007/s12052-010-0249-6 . ISSN 1936-6434 . S2CID 31979188 . ^ Dunsworth HM (September 2010). "Origin of the Genus Homo" . Evolution: Education and Outreach . 3 (3): 353–366. doi : 10.1007/s12052-010-0247-8 . ISSN 1936-6434 . S2CID 43116946 . ^ Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1698): 20150248. doi : 10.1098/rstb.2015.0248 . PMC 4920303 . PMID 27298460 . S2CID 20267830 . ^ Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia" . Science . 347 (6228): 1352–1355. Bibcode : 2015Sci...347.1352V . doi : 10.1126/science.aaa1343 . PMID 25739410 . ^ Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature . 559 (7715): 608–612. Bibcode : 2018Natur.559..608Z . doi : 10.1038/s41586-018-0299-4 . PMID 29995848 . S2CID 49670311 . ^ Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF) . Nature . 546 (7657): 289–292. Bibcode : 2017Natur.546..289H . doi : 10.1038/nature22336 . PMID 28593953 . S2CID 256771372 . Archived (PDF) from the original on 8 January 2020 . Retrieved 30 July 2022 . ^ "Out of Africa Revisited". Science (This Week in Science ). 308 (5724): 921. 13 May 2005. doi : 10.1126/science.308.5724.921g . ISSN 0036-8075 . S2CID 220100436 . ^ Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature . 423 (6941): 692–693, 695. Bibcode : 2003Natur.423..692S . doi : 10.1038/423692a . PMID 12802315 . S2CID 26693109 . ^ Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?" . actionbioscience . Washington, DC: American Institute of Biological Sciences . Archived from the original on 17 June 2021 . Retrieved 23 November 2009 . ^ Marean, Curtis; et al. (2007). "Early human use of marine resources and pigment in South Africa during the Middle Pleistocene" (PDF) . Nature . 449 (7164): 905–908. Bibcode : 2007Natur.449..905M . doi : 10.1038/nature06204 . PMID 17943129 . S2CID 4387442 . Archived (PDF) from the original on 2023-05-25 . Retrieved 2023-01-07 . ^ Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB (2018). "Long-distance stone transport and pigment use in the earliest Middle Stone Age" . Science . 360 (6384): 90–94. Bibcode : 2018Sci...360...90B . doi : 10.1126/science.aao2646 . PMID 29545508 . ^ Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology . 26 (6): 827–833. Bibcode : 2016CBio...26..827P . doi : 10.1016/j.cub.2016.01.037 . hdl : 2440/114930 . PMID 26853362 . S2CID 140098861 . ^ Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture" . Genome Research . 25 (4): 459–466. doi : 10.1101/gr.186684.114 . PMC 4381518 . PMID 25770088 . ^ Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia" . Science . 331 (6016): 453–456. Bibcode : 2011Sci...331..453A . doi : 10.1126/science.1199113 . PMID 21273486 . S2CID 20296624 . Archived from the original on 27 April 2011 . Retrieved 1 May 2011 . ^ Rincon P (27 January 2011). "Humans 'left Africa much earlier' " . BBC News . Archived from the original on 9 August 2012. ^ Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature . 547 (7663): 306–310. Bibcode : 2017Natur.547..306C . doi : 10.1038/nature22968 . hdl : 2440/107043 . PMID 28726833 . S2CID 205257212 . ^ Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF) . University of Waikato . Archived (PDF) from the original on 22 May 2010 . Retrieved 29 April 2010 . ^ Appenzeller T (May 2012). "Human migrations: Eastern odyssey" . Nature . 485 (7396): 24–26. Bibcode : 2012Natur.485...24A . doi : 10.1038/485024a . PMID 22552074 . ^ Reich D , Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" . Nature . 468 (7327): 1053–1060. Bibcode : 2010Natur.468.1053R . doi : 10.1038/nature09710 . hdl : 10230/25596 . PMC 4306417 . PMID 21179161 . ^ Hammer MF (May 2013). "Human Hybrids" (PDF) . Scientific American . 308 (5): 66–71. Bibcode : 2013SciAm.308e..66H . doi : 10.1038/scientificamerican0513-66 . PMID 23627222 . Archived from the original (PDF) on 24 August 2018. ^ Yong E (July 2011). "Mosaic humans, the hybrid species" . New Scientist . 211 (2823): 34–38. Bibcode : 2011NewSc.211...34Y . doi : 10.1016/S0262-4079(11)61839-3 . ^ Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology . 43 (1): 1–11. doi : 10.1007/s11692-015-9348-1 . S2CID 14329491 . ^ Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans" . Genome Research . 20 (5): 547–553. doi : 10.1101/gr.076000.108 . PMC 2860157 . PMID 20439435 . ^ Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans" . Science . 334 (6052): 89–94. Bibcode : 2011Sci...334...89A . doi : 10.1126/science.1209202 . PMC 3677943 . PMID 21868630 . ^ Sandel, Aaron A. (30 July 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness" . American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . Archived from the original on 22 July 2023 . Retrieved 22 July 2023 . ^ Boyd R , Silk JB (2003). How Humans Evolved . New York: Norton . ISBN 978-0-393-97854-4 . ^ Little, Michael A.; Blumler, Mark A. (2015). "Hunter-Gatherers" . In Muehlenbein, Michael P. (ed.). Basics in Human Evolution . Boston: Academic Press. pp. 323–335. ISBN 978-0-12-802652-6 . Archived from the original on 3 July 2022 . Retrieved 30 July 2022 . ^ Scarre, Chris (2018). "The world transformed: from foragers and farmers to states and empires". In Scarre, Chris (ed.). The Human Past: World Prehistory and the Development of Human Societies (4th ed.). London: Thames & Hudson . pp. 174–197. ISBN 978-0-500-29335-5 . ^ Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe . Walnut Creek, CA: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5 . OCLC 855969933 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society . Elsevier. pp. 103–131. doi : 10.1016/B978-0-12-805247-1.00006-X . ISBN 978-0-12-805247-1 . ^ He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China" . The Holocene . 27 (12): 1885–1898. Bibcode : 2017Holoc..27.1885H . doi : 10.1177/0959683617708455 . S2CID 133660098 . Archived from the original on 20 November 2021 . Retrieved 30 July 2022 . ^ Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago" . Proceedings of the National Academy of Sciences of the United States of America . 106 (18): 7367–7372. Bibcode : 2009PNAS..106.7367L . doi : 10.1073/pnas.0900158106 . PMC 2678631 . PMID 19383791 . ^ Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea" . Science . 301 (5630): 189–193. doi : 10.1126/science.1085255 . PMID 12817084 . S2CID 10644185 . ^ Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication" . Science Advances . 5 (5): eaaw1947. Bibcode : 2019SciA....5.1947S . doi : 10.1126/sciadv.aaw1947 . PMC 6527260 . PMID 31114806 . ^ Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF) . Current Anthropology . 58 (5): 673–683. doi : 10.1086/693898 . S2CID 149402650 . Archived (PDF) from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science . 38 (2): 312–322. Bibcode : 2011JArSc..38..312M . doi : 10.1016/j.jas.2010.09.007 . ^ Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries . Cengage Learning. ISBN 978-1-285-66153-7 . Archived from the original on 27 February 2021 . Retrieved 11 July 2015 . ^ Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500 . Cenpage Learning. ISBN 978-1-285-98299-1 . Archived from the original on 10 August 2023 . Retrieved 11 July 2015 . ^ Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization . San Francisco: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3 . Archived from the original on 10 August 2023 . Retrieved 30 July 2022 . ^ Garfinkle, Steven J. (2013). "Ancient Near Eastern City-States". In Peter Fibiger Bang ; Walter Scheidel (eds.). The Oxford Handbook of the State in the Ancient Near East and Mediterranean . Oxford Academic. pp. 94–119. doi : 10.1093/oxfordhb/9780195188318.013.0004 . ISBN 978-0-19-518831-8 . ^ Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi : 10.1002/9781119193814.ch2 . ISBN 978-1-119-19329-6 . S2CID 216180781 . ^ Robinson A (October 2015). "Ancient civilization: Cracking the Indus script" . Nature . 526 (7574): 499–501. Bibcode : 2015Natur.526..499R . doi : 10.1038/526499a . PMID 26490603 . S2CID 4458743 . ^ Crawford H (2013). "Trade in the Sumerian world". The Sumerian World . Routledge. pp. 447–461. ISBN 978-1-136-21911-5 . ^ Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles" . Acta Archaeologica Academiae Scientiarum Hungaricae . 69 (2): 271–298. doi : 10.1556/072.2018.69.2.3 . ISSN 0001-5210 . S2CID 115685157 . Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Pryor FL (1985). "The Invention of the Plow" . Comparative Studies in Society and History . 27 (4): 727–743. doi : 10.1017/S0010417500011749 . ISSN 0010-4175 . JSTOR 178600 . S2CID 144840498 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Carter R (2012). "19. Watercraft ". In Potts DT (ed.). A companion to the archaeology of the ancient Near East . Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0 . Archived from the original on 28 April 2015 . Retrieved 8 February 2014 . ^ Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction . CUP Archive. p. 1. ISBN 978-0-521-40340-5 . ^ Robson E (2008). Mathematics in ancient Iraq: A social history . Princeton University Press. pp. xxi. ^ Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza" . Technology and Culture . 44 (2): 340–354. doi : 10.1353/tech.2003.0063 . ISSN 0040-165X . JSTOR 25148110 . S2CID 109998651 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Voosen P (August 2018). "New geological age comes under fire". Science . 361 (6402): 537–538. Bibcode : 2018Sci...361..537V . doi : 10.1126/science.361.6402.537 . PMID 30093579 . S2CID 51954326 . ^ Saggs HW (2000). Babylonians . Univ of California Press. p. 7. ISBN 978-0-520-20222-1 . ^ Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory . 12 (4): 335–364. doi : 10.1007/s10816-005-8460-4 . ISSN 1573-7764 . S2CID 53393440 . ^ Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans" . Nature . 548 (7666): 214–218. Bibcode : 2017Natur.548..214L . doi : 10.1038/nature23310 . PMC 5565772 . PMID 28783727 . ^ Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC . Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8 . ^ Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change . 6 (4): 369–382. Bibcode : 2015WIRCC...6..369K . doi : 10.1002/wcc.345 . S2CID 128460316 . ^ Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science . 39 (6): 1862–1870. Bibcode : 2012JArSc..39.1862D . doi : 10.1016/j.jas.2012.01.029 . ^ Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory . Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi : 10.1007/978-1-4419-6633-9_11 . ISBN 978-1-4419-6633-9 . ^ Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography . United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1 . ^ Beard M (2 October 2015). "Why ancient Rome matters to the modern world" . The Guardian . Archived from the original on 14 April 2021 . Retrieved 17 April 2021 . ^ Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece" . Stanford University . Archived from the original on 18 April 2021 . Retrieved 17 April 2021 . ^ Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature . 582 (7813): 530–533. Bibcode : 2020Natur.582..530I . doi : 10.1038/s41586-020-2343-4 . PMID 32494009 . S2CID 219281856 . ^ Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar" . Latin American Antiquity . 28 (1): 88–104. doi : 10.1017/laq.2016.4 . ISSN 1045-6635 . S2CID 164417025 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida" . Proceedings of the Seminar for Arabian Studies . 46 : 25–40. ISSN 0308-8421 . JSTOR 45163415 . Archived from the original on 28 April 2022 . Retrieved 30 July 2022 . ^ Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration . 21 (1): 25–86. doi : 10.1080/01900699808525297 . ISSN 0190-0692 . ^ Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age" . Journal of the American Oriental Society . 96 (1): 15–26. doi : 10.2307/599886 . ISSN 0003-0279 . JSTOR 599886 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty" . Architectural History . 63 : 1–36. doi : 10.1017/arh.2020.1 . ISSN 0066-622X . S2CID 229716130 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question" . Climate . 6 (4): 90. Bibcode : 2018Clim....6...90M . doi : 10.3390/cli6040090 . ^ Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World . New York: Oxford University Press. p. 72. ISBN 978-0-19-532819-6 . Retrieved 30 July 2022 . ^ Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies . International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi : 10.1007/978-3-319-24774-8_2 . ISBN 978-3-319-24774-8 . ^ Vidal-Nanquet P (1987). The Harper Atlas of World History . Harper & Row Publishers. p. 76. ^ Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land . Simon and Schuster. ISBN 978-1-84983-770-5 . ^ Adam King (2002). "Mississippian Period: Overview" . New Georgia Encyclopedia . Archived from the original on 19 August 2009 . Retrieved 15 November 2009 . ^ Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism . Cambridge University Press. p. 2. ISBN 0-521-31896-3 . ^ May T (2013). The Mongol Conquests in World History . Reaktion Books. p. 7. ISBN 978-1-86189-971-2 . ^ Canós-Donnay S (25 February 2019). "The Empire of Mali" . Oxford Research Encyclopedia of African History . Oxford University Press. doi : 10.1093/acrefore/9780190277734.013.266 . ISBN 978-0-19-027773-4 . Archived from the original on 20 October 2021 . Retrieved 7 May 2021 . ^ Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity" . Asian Perspectives . 37 (2): 135–164. ^ Kafadar C (1 January 1994). "Ottomans and Europe" . In Brady T, Oberman T, Tracy JD (eds.). Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation . Brill. pp. 589–635. doi : 10.1163/9789004391659_019 . ISBN 978-90-04-39165-9 . Archived from the original on 2 May 2022 . Retrieved 17 April 2021 . ^ Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan" . Oxford Research Encyclopedia of Asian History . Oxford University Press. doi : 10.1093/acrefore/9780190277727.013.72 . ISBN 978-0-19-027772-7 . Archived from the original on 12 August 2021 . Retrieved 7 May 2021 . ^ Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing" . Pacific Affairs . 83 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526–1857)" . Al-Ta Lim Journal . 23 (2): 128–138. doi : 10.15548/jt.v23i2.228 . ISSN 2355-7893 . Archived from the original on 7 April 2022 . Retrieved 30 July 2022 . ^ Kirkpatrick R (2002). The European Renaissance, 1400–1600 . Routledge. p. 1. ISBN 978-1-317-88646-4 . OCLC 893909816 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Arnold D (2002). The Age of Discovery, 1400–1600 (Second ed.). Routledge. pp. xi. ISBN 978-1-136-47968-7 . OCLC 859536800 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics" . Theoretical Inquiries in Law . 11 (1). doi : 10.2202/1565-3404.1239 . ISSN 1565-3404 . S2CID 56216309 . Archived from the original on 26 August 2021 . Retrieved 30 July 2022 . ^ Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews . 20 (1–3): 277–299. Bibcode : 2001QSRv...20..277J . doi : 10.1016/S0277-3791(00)00116-5 . ^ Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature" . The Journal of African History . 30 (3): 365–394. doi : 10.1017/S0021853700024439 . ISSN 0021-8537 . JSTOR 182914 . S2CID 161321949 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide . London: Palgrave Macmillan UK. pp. 273–295. doi : 10.1057/9780230297784_11 . ISBN 978-0-230-29778-4 . ^ Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour . 38 (3–4): 157–158. doi : 10.1016/j.endeavour.2014.10.001 . PMID 25457642 . ^ "Greatest Engineering Achievements of the 20th Century" . National Academy of Engineering . Archived from the original on 6 April 2015 . Retrieved 7 April 2015 . ^ Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776 . New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0 . OCLC 299054528 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815" . Journal of Global History . 1 (1): 123–149. doi : 10.1017/S1740022806000076 . ISSN 1740-0228 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Zimmerman AF (November 1931). "Spain and Its Colonies, 1808–1820" . The Hispanic American Historical Review . 11 (4): 439–463. doi : 10.2307/2506251 . JSTOR 2506251 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ David S (2011). "British History in depth: Slavery and the 'Scramble for Africa' " . BBC . Archived from the original on 24 March 2022 . Retrieved 5 May 2021 . ^ Raudzens G (2004). "The Australian Frontier Wars, 1788–1838 (review)" . The Journal of Military History . 68 (3): 957–959. doi : 10.1353/jmh.2004.0138 . ISSN 1543-7795 . S2CID 162259092 . ^ Clark CM (2012). "Polarization of Europe, 1887–1907". The sleepwalkers : how Europe went to war in 1914 . London: Allen Lane. ISBN 978-0-7139-9942-6 . OCLC 794136314 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Robert Dahl (1989). Democracy and Its Critics . Yale UP. pp. 239–240 . ISBN 0-300-15355-4 . ^ McDougall WA (May 1985). "Sputnik, the space race, and the Cold War" . Bulletin of the Atomic Scientists . 41 (5): 20–25. Bibcode : 1985BuAtS..41e..20M . doi : 10.1080/00963402.1985.11455962 . ISSN 0096-3402 . ^ Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?" . Journal of Peace Research . 30 (2): 163–179. doi : 10.1177/0022343393030002004 . ISSN 0022-3433 . S2CID 5482851 . Archived from the original on 21 February 2022 . Retrieved 30 July 2022 . ^ Sachs JD (April 2017). "Globalization – In the Name of Which Freedom?" . Humanistic Management Journal . 1 (2): 237–252. doi : 10.1007/s41463-017-0019-5 . ISSN 2366-603X . S2CID 133030709 . ^ "World" . The World Factbook . CIA . 17 May 2016. Archived from the original on 26 January 2021 . Retrieved 2 October 2016 . ^ "World Population Prospects: The 2017 Revision" (PDF) . United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17. Archived (PDF) from the original on 26 June 2019 . Retrieved 30 July 2022 . ^ "The World's Cities in 2018" (PDF) . United Nations . Archived (PDF) from the original on 1 November 2018. ^ Rector RK (2016). The Early River Valley Civilizations (First ed.). New York: Rosen Publishing. p. 10. ISBN 978-1-4994-6329-3 . OCLC 953735302 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ "How People Modify the Environment" (PDF) . Westerville City School District . Archived (PDF) from the original on 25 February 2021 . Retrieved 13 March 2019 . ^ "Natural disasters and the urban poor" (PDF) . World Bank . October 2003. Archived (PDF) from the original on 9 August 2017. ^ Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities . [London]: Routledge. pp. x. ISBN 978-1-135-01559-6 . OCLC 889953315 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Piantadosi CA (2003). The biology of human survival : life and death in extreme environments . Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5 . OCLC 70215878 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Toups, M.A.; Kitchen, A.; Light, J.E.; Reed, D.L. (2011). "Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa" . Molecular Biology and Evolution . 28 (1): 29–32. doi : 10.1093/molbev/msq234 . PMC 3002236 . PMID 20823373 . ^ O'Neil D. "Human Biological Adaptability; Overview" . Palomar College. Archived from the original on 6 March 2013 . Retrieved 6 January 2013 . ^ "Population distribution and density" . BBC. Archived from the original on 23 June 2017 . Retrieved 26 June 2017 . ^ Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management . 30 (4): 492–507. doi : 10.1007/s00267-002-2737-0 . hdl : 10072/6758 . PMID 12481916 . S2CID 25834286 . ^ Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica" . Vanderbilt Journal of Transnational Law . 23 : 819. Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ "Mission to Mars: Mars Science Laboratory Curiosity Rover" . Jet Propulsion Laboratory. Archived from the original on 18 August 2015 . Retrieved 26 August 2015 . ^ "Touchdown! Rosetta's Philae probe lands on comet" . European Space Agency. 12 November 2014. Archived from the original on 22 August 2015 . Retrieved 26 August 2015 . ^ "NEAR-Shoemaker" . NASA . Archived from the original on 26 August 2015 . Retrieved 26 August 2015 . ^ Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station" . JSC Features . Johnson Space Center . Archived from the original on 16 February 2012 . Retrieved 13 February 2012 . ^ Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth" . Proceedings of the National Academy of Sciences of the United States of America . 115 (25): 6506–6511. Bibcode : 2018PNAS..115.6506B . doi : 10.1073/pnas.1711842115 . PMC 6016768 . PMID 29784790 . ^ Tellier LN (2009). Urban world history: an economic and geographical perspective . Presses de l'Université du Québec. p. 26. ISBN 978-2-7605-1588-8 . Retrieved 30 July 2022 . ^ Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, CA: Dickenson Pub. Co. ISBN 978-0-8221-0166-6 . ^ Harl KW (1998). "Population estimates of the Roman Empire" . Tulane.edu. Archived from the original on 7 May 2016 . Retrieved 8 December 2012 . ^ Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis" . International Journal of Hygiene and Environmental Health . 207 (2): 165–178. doi : 10.1078/1438-4639-00259 . PMC 7128933 . PMID 15031959 . ^ "World's population reaches six billion" . BBC News . 5 August 1999. Archived from the original on 15 April 2008 . Retrieved 5 February 2008 . ^ United Nations. "World population to reach 8 billion on 15 November 2022" . United Nations . Archived from the original on 20 January 2023 . Retrieved 27 October 2022 . ^ "Eight billion people, SARS-CoV-2 ancestor and illegal fishing" . Nature . 611 (641): 641. 23 November 2022. Bibcode : 2022Natur.611..641. . doi : 10.1038/d41586-022-03792-4 . S2CID 253764233 . Archived from the original on 26 January 2023 . Retrieved 26 January 2023 . ^ "World Population to Hit Milestone With Birth of 7 Billionth Person" . PBS NewsHour . 27 October 2011. Archived from the original on 24 September 2017 . Retrieved 11 February 2018 . ^ "68% of the world population projected to live in urban areas by 2050, says UN" . United Nations Department of Economic and Social Affairs (DESA) . 16 May 2018. Archived from the original on 10 March 2021 . Retrieved 18 April 2021 . ^ Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF) . U.S. Department of Justice , Bureau of Justice Statistics. Archived (PDF) from the original on 24 February 2013 . Retrieved 1 October 2006 . ^ Roopnarine PD (March 2014). "Humans are apex predators" . Proceedings of the National Academy of Sciences of the United States of America . 111 (9): E796. Bibcode : 2014PNAS..111E.796R . doi : 10.1073/pnas.1323645111 . PMC 3948303 . PMID 24497513 . ^ Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature" . Science . AAAS . Archived from the original on 26 October 2021 . Retrieved 9 May 2021 . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use – principally agriculture – that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.) ^ Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions" . Proceedings of the National Academy of Sciences of the United States of America . 103 (29): 10941–10946. Bibcode : 2006PNAS..10310941P . doi : 10.1073/pnas.0604181103 . PMC 1544153 . PMID 16829570 . ^ Collins D (1976). The Human Revolution: From Ape to Artist . Phaidon. p. 208 . ISBN 978-0-7148-1676-0 . ^ Weisberger, Mindy (March 23, 2024). "Why don't humans have tails? Scientists find answers in an unlikely place" . CNN . Archived from the original on March 24, 2024 . Retrieved March 24, 2024 . ^ Marks JM (2001). Human Biodiversity: Genes, Race, and History . Transaction Publishers. p. 16. ISBN 978-0-202-36656-2 . ^ Gea, J (2008). "The Evolution of the Human Species: A Long Journey for the Respiratory System". Archivos de Bronconeumología ((English Edition)) . 44 (5): 263–270. doi : 10.1016/S1579-2129(08)60042-7 . ^ O'Neil D. "Humans" . Primates . Palomar College. Archived from the original on 11 January 2013 . Retrieved 6 January 2013 . ^ "How to be Human: The reason we are so scarily hairy" . New Scientist . 2017. Archived from the original on 25 February 2021 . Retrieved 29 April 2020 . ^ Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . ^ Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White" . Evolution: Library . PBS. Archived from the original on 16 February 2013 . Retrieved 6 January 2013 . ^ Roser M, Appel C, Ritchie H (8 October 2013). "Human Height" . Our World in Data . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ "Senior Citizens Do Shrink – Just One of the Body Changes of Aging" . News . Senior Journal. Archived from the original on 19 February 2013 . Retrieved 6 January 2013 . ^ Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology . 136 (1): 71–84. doi : 10.1016/S1095-6433(02)00294-5 . PMID 14527631 . ^ "Human weight" . Articleworld.org. Archived from the original on 8 December 2011 . Retrieved 10 December 2011 . ^ Schlessingerman A (2003). "Mass Of An Adult" . The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018 . Retrieved 31 December 2017 . ^ Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology) . Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1 . Retrieved 5 April 2009 . ^ Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care" . British Journal of Anaesthesia . 85 (1): 91–108. doi : 10.1093/bja/85.1.91 . PMID 10927998 . ^ Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology . 93 (1): 1–16. doi : 10.1086/696721 . ISSN 0033-5770 . S2CID 90757192 . ^ Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance" . The New York Times . Archived from the original on 5 November 2015. ^ John B. "What is the role of sweating glands in balancing body temperature when running a marathon?" . Livestrong.com. Archived from the original on 31 January 2013 . Retrieved 6 January 2013 . ^ Shave, R. E.; Lieberman, D. E.; Drane, A. L.; et al. (2019). "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart" . PNAS . 116 (40): 19905–19910. Bibcode : 2019PNAS..11619905S . doi : 10.1073/pnas.1906902116 . PMC 6778238 . PMID 31527253 . ^ Ríos, L; Sleeper, M. M.; Danforth, M. D.; et al. (2023). "The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution" . Scientific Reports . 13 (6841): 6841. Bibcode : 2023NatSR..13.6841R . doi : 10.1038/s41598-023-33675-1 . hdl : 10261/309357 . PMC 10133235 . PMID 37100851 . ^ Therman E (1980). Human Chromosomes: Structure, Behavior, Effects . Springer US . pp. 112–124. doi : 10.1007/978-1-4684-0107-3 . ISBN 978-1-4684-0109-7 . S2CID 36686283 . ^ Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex" . Journal of Medical Genetics . 3 (2): 117–123. doi : 10.1136/jmg.3.2.117 . PMC 1012913 . PMID 6007033 . ^ Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics . 61 (3): 216–228. doi : 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S . PMID 8741866 . ^ Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics . 53 (1): 27–34. doi : 10.1038/s41588-020-00755-1 . PMID 33414551 . S2CID 230986741 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . Between any two humans, the amount of genetic variation – biochemical individuality – is about 0.1%. ^ Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human" . PLOS Biology . 5 (10): e254. doi : 10.1371/journal.pbio.0050254 . PMC 1964779 . PMID 17803354 . ^ Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research" . American Journal of Human Genetics . 77 (4): 519–532. doi : 10.1086/491747 . PMC 1275602 . PMID 16175499 . ^ "Chimps show much greater genetic diversity than humans" . Media . University of Oxford. Archived from the original on 18 December 2013 . Retrieved 13 December 2013 . ^ Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography" . Proceedings of the National Academy of Sciences of the United States of America . 95 (4): 1961–1967. Bibcode : 1998PNAS...95.1961H . doi : 10.1073/pnas.95.4.1961 . PMC 19224 . PMID 9465125 . ^ Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans" . Proceedings of the National Academy of Sciences of the United States of America . 94 (7): 3100–3103. Bibcode : 1997PNAS...94.3100J . doi : 10.1073/pnas.94.7.3100 . PMC 20328 . PMID 9096352 . ^ Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story" . The New York Times . Archived from the original on 14 January 2012 . Retrieved 13 February 2012 . ^ Pennisi E (February 2001). "The human genome". Science . 291 (5507): 1177–1180. doi : 10.1126/science.291.5507.1177 . PMID 11233420 . S2CID 38355565 . ^ Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature . 590 (7845): 220–221. Bibcode : 2021Natur.590..220R . doi : 10.1038/d41586-021-00237-2 . PMID 33568827 . S2CID 231882262 . ^ Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations" . Nature . 467 (7311): 52–58. Bibcode : 2010Natur.467...52T . doi : 10.1038/nature09298 . PMC 3173859 . PMID 20811451 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private , common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture. ^ Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes" . Genome Biology . 11 (5): 206. doi : 10.1186/gb-2010-11-5-206 . PMC 2898077 . PMID 20441615 . ^ Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature . 325 (6099): 31–36. Bibcode : 1987Natur.325...31C . doi : 10.1038/325031a0 . PMID 3025745 . S2CID 4285418 . ^ Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock" . American Journal of Human Genetics . 84 (6): 740–759. doi : 10.1016/j.ajhg.2009.05.001 . PMC 2694979 . PMID 19500773 . ^ "University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history" . 20 August 2017. Archived from the original on 20 August 2017. ^ Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females" . Science . 341 (6145): 562–565. Bibcode : 2013Sci...341..562P . doi : 10.1126/science.1237619 . PMC 4032117 . PMID 23908239 . ^ Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set . John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1 . ^ Jukic AM, Baird DD, Weinberg CR , McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation" . Human Reproduction . 28 (10): 2848–2855. doi : 10.1093/humrep/det297 . PMC 3777570 . PMID 23922246 . ^ Klossner NJ (2005). Introductory Maternity Nursing . Lippincott Williams & Wilkins. p. 103. ISBN 978-0-7817-6237-3 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . The fetal stage is from the beginning of the 9th week after fertilization and continues until birth ^ World Health Organization (November 2014). "Preterm birth Fact sheet N°363" . who.int . Archived from the original on 7 March 2015 . Retrieved 6 March 2015 . ^ Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application" . American Journal of Obstetrics and Gynecology . 218 (2S): S619–S629. doi : 10.1016/j.ajog.2017.12.010 . PMID 29422204 . S2CID 46810955 . ^ "What is the average baby length? Growth chart by month" . www.medicalnewstoday.com . 18 March 2019. Archived from the original on 27 January 2021 . Retrieved 18 April 2021 . ^ Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal . 5 (2): 113–122. PMID 15024783 . ^ Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology . 35 (S15): 89–124. doi : 10.1002/ajpa.1330350605 . ISSN 1096-8644 . ^ Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma" . American Journal of Obstetrics and Gynecology . 222 (1): 3–16. doi : 10.1016/j.ajog.2019.06.043 . PMC 9069416 . PMID 31251927 . S2CID 195761874 . ^ Barras C (22 December 2016). "The real reasons why childbirth is so painful and dangerous". BBC. ^ Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?" . Newsweek . Archived from the original on 28 June 2007. A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa , compared to 1 in 2,800 in developed countries . ^ Rush D (July 2000). "Nutrition and maternal mortality in the developing world" . The American Journal of Clinical Nutrition . 72 (1 Suppl): 212S–240S. doi : 10.1093/ajcn/72.1.212S . PMID 10871588 . ^ Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour . Oxford University Press. p. 7. ISBN 978-0-19-958696-7 . Retrieved 30 July 2022 . ^ Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning . p. 296. ISBN 978-0-495-60037-4 . Archived from the original on 3 October 2023 . Retrieved 30 July 2022 . ^ Schuiling KD, Likis FE (2016). Women's Gynecologic Health . Jones & Bartlett Learning . p. 22. ISBN 978-1-284-12501-6 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13. ^ Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy . SAGE Publications . pp. 18–19. ISBN 978-1-4833-6475-9 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average). ^ Mintz S (1993). "Life stages". Encyclopedia of American Social History . 3 : 7–33. ^ Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?" . Indian Journal of Endocrinology and Metabolism . 18 (Suppl 1): S53-62. doi : 10.4103/2230-8210.145075 . PMC 4266869 . PMID 25538878 . ^ Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?" . Biology of Reproduction . 79 (3): 398–406. doi : 10.1095/biolreprod.108.068536 . PMC 2553520 . PMID 18495681 . ^ Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality . New York: Basic Books. pp. 167–170. ISBN 978-0-465-03127-6 . ^ Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology . 10 (2): 43–57. doi : 10.1002/evan.1013 . S2CID 1665503 . ^ Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth" . USC Trojan Family Magazine . Archived from the original on 13 December 2010 . Retrieved 7 December 2010 . ^ Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex" . Society of Actuaries. Archived from the original on 1 July 2013. ^ "Life expectancy at birth, female (years)" . World Bank . 2018. Archived from the original on 24 January 2021 . Retrieved 13 October 2020 . ^ "Life expectancy at birth, male (years)" . World Bank . 2018. Archived from the original on 24 February 2021 . Retrieved 13 October 2020 . ^ Conceição P, et al. (2019). Human Development Report (PDF) . United Nations Development Programme. ISBN 978-92-1-126439-5 . Archived (PDF) from the original on 20 March 2021 . Retrieved 30 July 2022 . ^ "Human Development Report 2019" (PDF) . United Nations Development Programme . Archived from the original (PDF) on 22 April 2022 . Retrieved 30 July 2022 . ^ "The World Factbook" . U.S. Central Intelligence Agency. Archived from the original on 12 September 2009 . Retrieved 2 April 2005 . ^ "Chapter 1: Setting the Scene" (PDF) . UNFPA. 2012. Archived from the original (PDF) on 12 June 2013 . Retrieved 11 January 2013 . ^ Haenel H (1989). "Phylogenesis and nutrition". Die Nahrung . 33 (9): 867–887. PMID 2697806 . ^ Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable . pp. 264–265. Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods. ^ American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association . 103 (6): 748–765. doi : 10.1053/jada.2003.50142 . PMID 12778049 . ^ Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet" . American Journal of Physical Anthropology . 162 (S63): 84–109. doi : 10.1002/ajpa.23148 . PMID 28105723 . ^ Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century" . The American Journal of Clinical Nutrition . 81 (2): 341–354. doi : 10.1093/ajcn.81.2.341 . PMID 15699220 . ^ Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context" . The Proceedings of the Nutrition Society . 61 (4): 517–526. doi : 10.1079/PNS2002180 . PMID 12691181 . ^ John Carey (2023). "Unearthing the origins of agriculture" . Proceedings of the National Academy of Sciences . 120 (15): e2304407120. Bibcode : 2023PNAS..12004407C . doi : 10.1073/pnas.2304407120 . PMC 10104519 . PMID 37018195 . ^ Ayelet Shavit; Gonen Sharon (2023). "Can models of evolutionary transition clarify the debates over the Neolithic Revolution?" . Philosophical Transactions of the Royal Society B . 378 (1872). doi : 10.1098/rstb.2021.0413 . PMC 9869441 . PMID 36688395 . } ^ Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences" . The American Journal of Clinical Nutrition . 90 (3): 707S–711S. doi : 10.3945/ajcn.2009.27462B . PMID 19656837 . ^ Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology . 69 (5): 605–628. PMID 9299882 . ^ Gibbons A. "The Evolution of Diet" . National Geographic . Archived from the original on 18 August 2014 . Retrieved 18 April 2021 . ^ Ritchie H, Roser M (20 August 2017). "Diet Compositions" . Our World in Data . Archived from the original on 25 August 2021 . Retrieved 30 July 2022 . ^ Lieberson AD (2004). "How Long Can a Person Survive without Food?" . Scientific American . Archived from the original on 14 February 2019 . Retrieved 18 April 2021 . ^ Spector D (9 March 2018). "Here's how many days a person can survive without water" . Business Insider Australia . Archived from the original on 26 June 2014 . Retrieved 18 April 2021 . ^ Holmes J. "Losing 25,000 to Hunger Every Day" . United Nations . Archived from the original on 27 May 2020 . Retrieved 18 April 2021 . ^ Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic" . NPR . Archived from the original on 28 June 2021 . Retrieved 18 April 2021 . ^ Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet . 349 (9063): 1436–1442. doi : 10.1016/S0140-6736(96)07495-8 . PMID 9164317 . S2CID 2569153 . ^ Haslam DW, James WP (October 2005). "Obesity". Lancet . 366 (9492): 1197–1209. doi : 10.1016/S0140-6736(05)67483-1 . PMID 16198769 . S2CID 208791491 . ^ Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine . 30 (3): 415–444, vii. doi : 10.1016/j.ccm.2009.05.001 . PMID 19700042 . ^ de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology . 2 (1): 45–55. doi : 10.1016/j.ehb.2003.11.001 . PMID 15463992 . ^ O'Neil D. "Adapting to Climate Extremes" . Human Biological Adaptability . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status" . PLOS Genetics . 13 (9): e1006977. doi : 10.1371/journal.pgen.1006977 . PMC 5600404 . PMID 28873402 . ^ Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics . 35 (4): 311–313. doi : 10.1038/ng1263 . PMID 14634648 . S2CID 20415396 . ^ Hedrick PW (October 2011). "Population genetics of malaria resistance in humans" . Heredity . 107 (4): 283–304. doi : 10.1038/hdy.2011.16 . PMC 3182497 . PMID 21427751 . ^ Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria" . British Journal of Haematology . 141 (3): 276–286. doi : 10.1111/j.1365-2141.2008.07085.x . PMID 18410566 . S2CID 28191911 . ^ Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea" . Frontiers in Ecology and Evolution . 5 . doi : 10.3389/fevo.2017.00025 . hdl : 11858/00-001M-0000-002C-DD87-4 . ISSN 2296-701X . S2CID 34882477 . ^ Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads" . Cell . 173 (3): 569–580.e15. doi : 10.1016/j.cell.2018.03.054 . PMID 29677510 . ^ Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology . 45 (1): 105–08. doi : 10.1086/381006 . S2CID 224795768 . ^ Roberts D (2011). Fatal Invention . London & New York: The New Press. ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation" . Proceedings of the National Academy of Sciences of the United States of America . 107 (Supplement_2): 8962–8968. Bibcode : 2010PNAS..107.8962J . doi : 10.1073/pnas.0914628107 . PMC 3024016 . PMID 20445093 . ^ Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF) . Journal of Human Evolution . 39 (1): 57–106. doi : 10.1006/jhev.2000.0403 . PMID 10896812 . Archived from the original (PDF) on 14 January 2012. ^ Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R" . American Journal of Human Genetics . 66 (4): 1351–1361. doi : 10.1086/302863 . PMC 1288200 . PMID 10733465 . ^ Robin A (1991). Biological Perspectives on Human Pigmentation . Cambridge: Cambridge University Press. ^ "The Science Behind the Human Genome Project" . Human Genome Project . US Department of Energy. Archived from the original on 2 January 2013 . Retrieved 6 January 2013 . Almost all (99.9%) nucleotide bases are exactly the same in all people. ^ O'Neil D. "Ethnicity and Race: Overview" . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation" . Nature Genetics . 36 (11 Suppl): S17-20. doi : 10.1038/ng1455 . PMID 15507998 . ^ O'Neil D. "Models of Classification" . Modern Human Variation . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Palmié S (May 2007). "Genomics, divination, 'racecraft' ". American Ethnologist . 34 (2): 205–222. doi : 10.1525/ae.2007.34.2.205 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations. ^ Goodman A. "Interview with Alan Goodman" . Race Power of and Illusion . PBS. Archived from the original on 29 October 2012 . Retrieved 6 January 2013 . ^ Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF) . New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012 . Retrieved 5 September 2013 . ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo ^ O'Neil D. "Overview" . Modern Human Variation . Palomar College. Archived from the original on 5 November 2012 . Retrieved 6 January 2013 . ^ Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" . American Journal of Human Genetics . 66 (3): 979–988. doi : 10.1086/302825 . PMC 1288178 . PMID 10712212 . ^ "New Research Proves Single Origin Of Humans In Africa" . Science Daily . 19 July 2007. Archived from the original on 4 November 2011 . Retrieved 5 September 2011 . ^ Manica A, Amos W, Balloux F , Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation" . Nature . 448 (7151): 346–348. Bibcode : 2007Natur.448..346M . doi : 10.1038/nature05951 . PMC 1978547 . PMID 17637668 . ^ Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals" . Cell . 180 (4): 677–687.e16. doi : 10.1016/j.cell.2020.01.012 . PMID 32004458 . S2CID 210955842 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations. ^ Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations" . Science Advances . 6 (7): eaax5097. Bibcode : 2020SciA....6.5097D . doi : 10.1126/sciadv.aax5097 . PMC 7015685 . PMID 32095519 . Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. ^ Pierce BA (2012). Genetics: A Conceptual Approach . Macmillan. p. 75. ISBN 978-1-4292-3252-4 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology . Cambridge University Press. p. 74. ISBN 978-0-521-87948-4 . Retrieved 30 July 2022 . ^ Fusco G, Minelli A (10 October 2019). The Biology of Reproduction . Cambridge University Press. p. 304. ISBN 978-1-108-49985-9 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution . 47 (4): 253–266. doi : 10.1016/j.jhevol.2004.07.004 . PMID 15454336 . ^ Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960–2002" (PDF) . Advance Data (347): 1–17. PMID 15544194 . Archived from the original (PDF) on 23 February 2011. ^ Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology . 66 (3): 254–262. doi : 10.1007/BF00235103 . hdl : 11375/22586 . PMID 8477683 . S2CID 206772211 . ^ Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity . Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi : 10.1007/978-3-319-70178-3_2 . ISBN 978-3-319-70177-6 . PMID 29224088 . ^ Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know" . International Journal of Women's Dermatology . 4 (3): 122–130. doi : 10.1016/j.ijwd.2018.03.002 . PMC 6116811 . PMID 30175213 . ^ Easter C. "Sex Linked" . National Human Genome Research Institute . Archived from the original on 14 April 2022 . Retrieved 18 April 2021 . ^ Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior . 27 (4): 283–296. doi : 10.1016/j.evolhumbehav.2005.11.003 . S2CID 32562654 . ^ "Gender, women, and health" . Reports from WHO 2002–2005 . Archived from the original on 25 June 2013. ^ Sax, Leonard (1 August 2002). "How common is lntersex? A response to Anne Fausto-Sterling" . The Journal of Sex Research . 39 (3): 174–178. doi : 10.1080/00224490209552139 . ISSN 0022-4499 . PMID 12476264 . S2CID 33795209 . ^ "3-D Brain Anatomy" . The Secret Life of the Brain . Public Broadcasting Service. Archived from the original on 5 September 2017 . Retrieved 3 April 2005 . ^ Stern P (22 June 2018). "The human prefrontal cortex is special" . Science . 360 (6395): 1311–1312. Bibcode : 2018Sci...360S1311S . doi : 10.1126/science.360.6395.1311-g . ISSN 0036-8075 . S2CID 149581944 . ^ Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?" . Journal of Intelligence . 2 (3): 119–121. doi : 10.3390/jintelligence2030119 . ISSN 2079-3200 . ^ "Humans not smarter than animals, just different, experts say" . phys.org . Archived from the original on 30 January 2021 . Retrieved 24 October 2020 . ^ Robson D. "We've got human intelligence all wrong" . www.bbc.com . Archived from the original on 31 January 2021 . Retrieved 24 October 2020 . ^ Owen J (26 February 2015). "Many Animals – Including Your Dog – May Have Horrible Short-Term Memories" . National Geographic News . Archived from the original on 19 April 2021 . Retrieved 6 September 2020 . ^ Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research" . American Journal of Physical Anthropology . 116 (S33): 3–24. doi : 10.1002/ajpa.20001 . PMC 2238342 . PMID 11786989 . ^ Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?" . ABC News (American) . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self" . New Scientist . Archived from the original on 18 February 2021 . Retrieved 22 April 2020 . ^ Beck J (2019). "Can We Really Know What Animals Are Thinking?" . Snopes . Archived from the original on 31 October 2021 . Retrieved 22 April 2020 . ^ Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies" . Sleep Medicine Reviews . 14 (4): 239–247. doi : 10.1016/j.smrv.2009.08.001 . PMC 2888649 . PMID 19896872 . ^ Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep" " . Science.howstuffworks.com. Archived from the original on 15 May 2012 . Retrieved 11 August 2012 . ^ Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience . 10 (11): 803–813. doi : 10.1038/nrn2716 . PMID 19794431 . S2CID 205505278 . ^ Empson J (2002). Sleep and dreaming (3rd ed.). New York: Palgrave/St. Martin's Press. ^ Lite J (29 July 2010). "How Can You Control Your Dreams?" . Scientific America . Archived from the original on 2 February 2015. ^ Domhoff W (2002). The scientific study of dreams . APA Press. ^ "Consciousness" . Merriam-Webster . Archived from the original on 7 September 2019 . Retrieved 4 June 2012 . ^ van Gulick R (2004). "Consciousness" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019 . Retrieved 30 July 2022 . ^ Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness . Wiley. ISBN 978-0-470-75145-9 . ^ Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy . Oxford University Press. ISBN 978-0-19-926479-7 . ^ Block N (June 1995). "On a confusion about a function of consciousness" . Behavioral and Brain Sciences . 18 (2): 227–247. doi : 10.1017/S0140525X00038474 . S2CID 246244859 . ^ Jaynes J (2000) [1976]. The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF) . Houghton Mifflin. ISBN 0-618-05707-2 . Archived from the original (PDF) on 7 August 2019 . Retrieved 25 October 2020 . ^ Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition . 12 (4): 717–731. doi : 10.1016/s1053-8100(03)00081-3 . PMID 14656513 . S2CID 10241157 . ^ Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness" . Stanford Encyclopedia of Philosophy . Archived from the original on 13 April 2021 . Retrieved 31 August 2014 . ^ Antony MV (2001). "Is consciousness ambiguous?". Journal of Consciousness Studies . 8 : 19–44. ^ "Cognition" . Lexico . Oxford University Press and Dictionary.com . Archived from the original on 8 July 2016 . Retrieved 6 May 2020 . ^ Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality . The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi : 10.1007/978-3-030-03633-1_14 . ISBN 978-3-030-03633-1 . S2CID 189379814 . ^ "American Psychological Association (2013). Glossary of psychological terms" . Apa.org. Archived from the original on 8 July 2014 . Retrieved 13 August 2014 . ^ "Developmental Psychology Studies Human Development Across the Lifespan" . www.apa.org . Archived from the original on 9 July 2014 . Retrieved 28 August 2017 . ^ Burman E (2017). Deconstructing Developmental Psychology . New York: Routledge. ISBN 978-1-138-84695-1 . ^ Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology : 307–314. doi : 10.1016/B0-12-657410-3/00510-9 . ISBN 978-0-12-657410-4 . ^ McLeod S (20 March 2020). "Maslow's Hierarchy of Needs" . Simplypsychology.org . Simply Scholar Limited. Archived from the original on 8 November 2018 . Retrieved 4 April 2020 . Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up. ^ Heckhausen J, Heckhausen H (28 March 2018). "Motivation and Action: Introduction and Overview". Motivation and Action . Introduction and Overview: Springer, Cham. p. 1. doi : 10.1007/978-3-319-65094-4_1 . ISBN 978-3-319-65093-7 . ^ Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews . 26 (2–3): 83–86. doi : 10.1016/s0165-0173(97)00064-7 . PMID 9651488 . S2CID 8504450 . ^ Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions . New York: Oxford University Press. pp. 291–293. ISBN 978-0-19-508944-8 . Emotional processing, but not emotions, can occur unconsciously. ^ Cabanac M (2002). "What is emotion?". Behavioural Processes . 60 (2): 69–83. doi : 10.1016/S0376-6357(02)00078-5 . PMID 12426062 . S2CID 24365776 . Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure) ^ Scirst DL (2011). Psychology Second Edition . New York: Worth Publishers. p. 310 . ISBN 978-1-4292-3719-2 . ^ Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality . 67 (2): 331–371. doi : 10.1111/1467-6494.00058 . PMID 10202807 . ^ Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory" . Frontiers in Psychology . 8 : 1454. doi : 10.3389/fpsyg.2017.01454 . PMC 5573739 . PMID 28883804 . ^ Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology . Oxford University Press. Archived from the original on 29 January 2021 . Retrieved 30 July 2022 . ^ Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals" . Industrial Psychiatry Journal . 24 (1): 54–58. doi : 10.4103/0972-6748.160934 . PMC 4525433 . PMID 26257484 . ^ Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions" . The American Psychologist . 56 (3): 218–226. doi : 10.1037/0003-066X.56.3.218 . PMC 3122271 . PMID 11315248 . ^ Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica . 90 (3): 387–411. doi : 10.11612/resphil.2013.90.3.5 . ^ Haybron DM (13 April 2014). "Happiness and Its Discontents" . The Opinion Pages . The New York Times. Archived from the original on 12 October 2018 . Retrieved 30 July 2022 . I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life. ^ Graham MC (2014). Facts of Life: ten issues of contentment . Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5 . ^ "Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy" . ScienceDaily . American Psychological Association . 14 August 2017. Archived from the original on 11 November 2020 . Retrieved 25 October 2020 . ^ Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality . Jones & Bartlett Publishers . pp. 4–10. ISBN 978-1-284-08154-1 . Retrieved 21 June 2017 . Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings. ^ Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives . Taylor & Francis . pp. 32–42. ISBN 978-0-7890-2671-2 . ^ Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology . 3 (4): 85–89. doi : 10.1097/01.XHA.0000432482.01760.b0 . S2CID 147235090 . ^ "Sexual orientation, homosexuality and bisexuality" . American Psychological Association . Archived from the original on 8 August 2013 . Retrieved 10 August 2013 . ^ Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science" . Psychological Science in the Public Interest . 17 (2): 45–101. doi : 10.1177/1529100616637616 . PMID 27113562 . ^ LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation . Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6 . Retrieved 30 July 2022 . ^ Balthazart J (2012). The Biology of Homosexuality . Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0 . Retrieved 30 July 2022 . ^ Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York: Basic Books. ISBN 978-0-465-00802-5 . ^ Fromm E (2000). The art of loving . New York: Harper Perennial. ISBN 978-0-06-095828-2 . ^ "Love, Actually: The science behind lust, attraction, and companionship" . Science in the News . 14 February 2017. Archived from the original on 28 October 2020 . Retrieved 25 October 2020 . ^ "What are the top 200 most spoken languages?" . Ethnologue: Languages of the World . 2020. Archived from the original on 12 January 2013 . Retrieved 30 July 2022 . ^ World . The World Factbook (Report). Central Intelligence Agency . Archived from the original on 26 January 2021 . Retrieved 15 November 2021 . ^ "The Changing Global Religious Landscape" . Pew Research Center. 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 30 July 2022 . ^ Ord T (2020). The Precipice: Existential Risk and the Future of Humanity . New York: Hachette Books. ISBN 978-0-316-48489-3 . Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence... ^ Goldman JG (2012). "Pay attention… time for lessons at animal school" . bbc.com . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding" . Science Advances . 4 (11): eaar8334. Bibcode : 2018SciA....4.8334W . doi : 10.1126/sciadv.aar8334 . PMC 6248967 . PMID 30474053 . ^ Johnson-Frey SH (July 2003). "What's so special about human tool use?" . Neuron . 39 (2): 201–204. doi : 10.1016/S0896-6273(03)00424-0 . PMID 12873378 . S2CID 18437970 . ^ Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology . 19 (1): 27–33. doi : 10.1016/j.conb.2009.02.003 . PMID 19328675 . S2CID 18277620 . In short, the evidence to date that animals have an understanding of folk physics is at best mixed. ^ Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To" . National Geographic News . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education" . Procedia - Social and Behavioral Sciences . The Proceedings of 6th World Conference on educational Sciences. 191 : 2565–2567. doi : 10.1016/j.sbspro.2015.04.690 . ISSN 1877-0428 . ^ McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species" . The Guardian . Archived from the original on 5 February 2021 . Retrieved 22 April 2020 . ^ Nicholls H (29 June 2015). "Babblers speak to the origin of language" . The Guardian . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Dasgupta S (2015). "Can any animals talk and use language like humans?" . bbc.com . Archived from the original on 2 May 2020 . Retrieved 22 April 2020 . Most animals are not vocal learners. ^ Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?" . Royal Society. Archived from the original on 18 January 2021 . Retrieved 24 October 2020 . ^ Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?" . BMC Biology . 15 (1): 64. doi : 10.1186/s12915-017-0405-3 . PMC 5525259 . PMID 28738867 . ^ Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist . 208 (2789): ii–iii. Bibcode : 2010NewSc.208D...2F . doi : 10.1016/S0262-4079(10)62961-2 . ISSN 0262-4079 . ^ Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments . London: Palgrave Macmillan UK. pp. 229–255. doi : 10.1057/978-1-137-58746-6_7 . ISBN 978-1-137-58746-6 . ^ "Culture | United Nations For Indigenous Peoples" . www.un.org . 5 June 2015. Archived from the original on 26 November 2020 . Retrieved 24 October 2020 . ^ Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World . New York: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1 . ^ Mavrody S (2013). Visual Art Forms: Traditional to Digital . Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9 . Retrieved 30 July 2022 . ^ "Types of Literary Arts and Their Understanding – bookfestivalscotland.com" . Bookfestival Scotland . 2020. Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ "Bachelor of Performing Arts" (PDF) . University of Otago . Archived (PDF) from the original on 14 December 2021 . Retrieved 30 July 2022 . ^ Brown S (24 October 2018). "Toward a Unification of the Arts" . Frontiers in Psychology . 9 : 1938. doi : 10.3389/fpsyg.2018.01938 . ISSN 1664-1078 . PMC 6207603 . PMID 30405470 . ^ "Culinary arts – How cooking can be an art" . Northern Contemporary Art . 21 October 2019. Archived from the original on 11 May 2021 . Retrieved 5 May 2021 . ^ Smuts A (1 January 2005). "Are Video Games Art?" . Contemporary Aesthetics (Journal Archive) . 3 (1). Archived from the original on 29 May 2022 . Retrieved 30 July 2022 . ^ Cameron IA, Pimlott N (September 2015). "Art of medicine" . Canadian Family Physician . 61 (9): 739–740. PMC 4569099 . PMID 26371092 . ^ Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy . 25 (4): 458–470. doi : 10.1080/10286632.2017.1311328 . ISSN 1028-6632 . S2CID 151443044 . ^ Morriss-Kay GM (February 2010). "The evolution of human artistic creativity" . Journal of Anatomy . 216 (2): 158–176. doi : 10.1111/j.1469-7580.2009.01160.x . PMC 2815939 . PMID 19900185 . ^ Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature . 518 (7538): 228–231. Bibcode : 2015Natur.518..228J . doi : 10.1038/nature13962 . PMID 25470048 . S2CID 4461751 . ^ St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave" . The New York Times . Archived from the original on 14 April 2020 . Retrieved 20 September 2018 . ^ Radford T (16 April 2004). "World's oldest jewellery found in cave" . The Guardian . ISSN 0261-3077 . Archived from the original on 12 February 2021 . Retrieved 23 September 2020 . ^ Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches . Amsterdam: Valiz. pp. 241–263. ^ Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia . 92 (92): 147–177. doi : 10.4436/JASS.92008 (inactive 2024-03-20). PMID 25020016 . {{ cite journal }} : CS1 maint: DOI inactive as of March 2024 ( link ) ^ Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness" (PDF) . NeuroImage . 103 : 55–64. doi : 10.1016/j.neuroimage.2014.09.009 . PMID 25224999 . S2CID 4727529 . ^ Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences . 1337 (1): 140–146. Bibcode : 2015NYASA1337..140K . doi : 10.1111/nyas.12632 . PMID 25773628 . S2CID 206224849 . ^ Chow D (22 March 2010). "Why Do Humans Dance?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 21 September 2020 . ^ Krakauer J (26 September 2008). "Why do we like to dance – And move to the beat?" . Scientific American . Archived from the original on 28 February 2021 . Retrieved 21 September 2020 . ^ Prior KS (21 June 2013). "How Reading Makes Us More Human" . The Atlantic . Archived from the original on 29 January 2021 . Retrieved 23 September 2020 . ^ Puchner M. "How stories have shaped the world" . www.bbc.com . Archived from the original on 5 January 2021 . Retrieved 23 September 2020 . ^ Dalley, Stephanie , ed. (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5 . ^ Hernadi P (2001). "Literature and Evolution" . SubStance . 30 (1/2): 55–71. doi : 10.2307/3685504 . ISSN 0049-2426 . JSTOR 3685504 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run" . The Guardian (U.S. ed.). New York. Archived from the original on 18 June 2022 . Retrieved 30 July 2022 . ^ Clark JD; de Heinzelin J ; Schick KD ; Hart WK; White TD ; WoldeGabriel G; Walter RC; Suwa G ; Asfaw B ; Vrba E ; H.-Selassie Y (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science . 264 (5167): 1907–1910. Bibcode : 1994Sci...264.1907C . doi : 10.1126/science.8009220 . PMID 8009220 . ^ Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use" . livescience.com . Archived from the original on 4 October 2020 . Retrieved 9 October 2020 . ^ Orban GA, Caruana F (2014). "The neural basis of human tool use" . Frontiers in Psychology . 5 : 310. doi : 10.3389/fpsyg.2014.00310 . PMC 3988392 . PMID 24782809 . ^ Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa" . Proceedings of the National Academy of Sciences of the United States of America . 109 (20): E1215-20. doi : 10.1073/pnas.1117620109 . PMC 3356665 . PMID 22474385 . ^ Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1696): 20150164. doi : 10.1098/rstb.2015.0164 . PMC 4874402 . PMID 27216521 . ^ Damiano J (2018). "Neolithic Era Tools: Inventing a New Age" . MagellanTV . Archived from the original on 5 January 2021 . Retrieved 9 October 2020 . ^ Deng Y, Wang P (2011). Ancient Chinese inventions . Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6 . OCLC 671710733 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Schifman J (9 July 2018). "The Entire History of Steel" . Popular Mechanics . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Wilkinson, Freddie (9 January 2020). "Industrial Revolution and Technology" . National Geographic Society . Archived from the original on 30 September 2020 . Retrieved 9 October 2020 . ^ Roser, Max ; Ritchie, Hannah (11 May 2013). "Technological Progress" . Our World in Data . Archived from the original on 10 September 2021 . Retrieved 30 July 2022 . ^ Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel" . The Atlantic . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Idinopulos TA (1998). "What Is Religion?" . CrossCurrents . 48 (3): 366–380. ISSN 0011-1953 . JSTOR 24460821 . Archived from the original on 13 October 2020 . Retrieved 30 July 2022 . ^ Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology . 54 (1): 377–402. doi : 10.1146/annurev.psych.54.101601.145024 . PMID 12171998 . ^ King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?" . The Atlantic . Archived from the original on 20 January 2021 . Retrieved 8 October 2020 . ^ Ball P (2015). "Complex societies evolved without belief in all-powerful deity" . Nature News . doi : 10.1038/nature.2015.17040 . S2CID 183474917 . Archived from the original on 16 May 2021 . Retrieved 30 July 2022 . ^ Culotta E (November 2009). "Origins. On the origin of religion". Science . 326 (5954): 784–787. Bibcode : 2009Sci...326..784C . doi : 10.1126/science.326_784 . PMID 19892955 . ^ Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation" . Evolution and Human Behavior . 32 (1): 41–49. doi : 10.1016/j.evolhumbehav.2010.07.008 . ISSN 1090-5138 . Archived from the original on 15 October 2020 . Retrieved 30 July 2022 . ^ Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA – Journal of Death and Dying . 41 (1): 5–22. doi : 10.2190/Q21C-5VED-GYW6-W091 . ISSN 0030-2228 . S2CID 145686249 . ^ McKay R, Whitehouse H (March 2015). "Religion and morality" . Psychological Bulletin . 141 (2): 447–473. doi : 10.1037/a0038455 . PMC 4345965 . PMID 25528346 . ^ Bernhard Nitsche; Marcus Schmücker, eds. (2023). God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality . De Gruyter . doi : 10.1515/9783110698343 . ISBN 978-3-11-069834-3 . ^ Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique" . Journal of Religion and Health (Submitted manuscript). 47 (2): 134–163. doi : 10.1007/s10943-008-9165-2 . PMC 8823950 . PMID 19105008 . S2CID 25349208 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular" . The Guardian . ISSN 0261-3077 . Archived from the original on 1 March 2021 . Retrieved 8 October 2020 . ^ Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe" . Pew Research Center . Archived from the original on 24 November 2019 . Retrieved 8 October 2020 . ^ "The Changing Global Religious Landscape" . Pew Research Center's Religion & Public Life Project . 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 8 October 2020 . ^ Di Christina, Mariette (September 2018). "A Very Human Story: Why Our Species Is Special" . Scientific American . Archived from the original on 24 November 2020 . Retrieved 27 September 2020 . ^ Andersen H , Hepburn B (2020). "Scientific Method" . In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Lo Presti R (2014). "History of science: The first scientist" . Nature . 512 (7514): 250–251. Bibcode : 2014Natur.512..250L . doi : 10.1038/512250a . ISSN 1476-4687 . S2CID 4394696 . ^ Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn . Springer. p. 1. ISBN 978-3-642-18904-3 . OCLC 883392276 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Needham, J ; Wang Ling (1954). Science and civilisation in China . Cambridge University Press. p. 111. ISBN 0-521-05799-X . OCLC 779676 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6 . OCLC 615209781 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017 . Retrieved 3 July 2017 . ^ Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition . Cambridge University Press. pp. 209–210. ISBN 978-1-107-01116-8 . ^ "Branches of Science" (PDF) . University of Chicago . Archived from the original (PDF) on 23 April 2017 . Retrieved 26 June 2017 . ^ "What is Philosophy?" . Department of Philosophy . Florida State University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ "Philosophy" . Definition, Systems, Fields, Schools, & Biographies . Encyclopedia Britannica. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day" . Philosophy and Phenomenological Research . 7 (3): 461. doi : 10.2307/2102800 . JSTOR 2102800 . Archived from the original on 31 March 2022 . Retrieved 30 July 2022 . ^ Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?" . ieet.org . Archived from the original on 4 March 2021 . Retrieved 8 August 2020 . ^ Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?" . European Journal of Information Systems . 27 (3): 263–277. doi : 10.1080/0960085X.2018.1470776 . hdl : 2086/16128 . ISSN 0960-085X . S2CID 64796132 . ^ Schizzerotto A. "Social Stratification" (PDF) . University of Trento . Archived from the original (PDF) on 20 March 2018 . Retrieved 3 July 2017 . ^ Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution . Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9 . OCLC 1082411117 . ^ "Social Role Theory of Sex Differences and Similarities : A Current Appraisal" . The Developmental Social Psychology of Gender . Psychology Press. 2000. pp. 137–188. doi : 10.4324/9781410605245-12 . ISBN 978-1-4106-0524-5 . Archived from the original on 30 April 2021 . Retrieved 10 June 2022 . ^ Blackstone, Amy (2003). "Gender Roles and Society" . In Miller, Julia R.; Lerner, Richard M.; Schiamberg, Lawrence B. (eds.). Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments . Sociology School Faculty Scholarship. Santa barbara, CA: ABC-CLIO. p. 335. Archived from the original on 16 May 2022 . Retrieved 30 July 2022 . ^ Nadal, Kevin L. (2017). The SAGE Encyclopedia of Psychology and Gender . SAGE Publications. p. 401. ISBN 978-1483384276 . Most cultures currently construct their societies based on the understanding of gender binary – the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization. ^ Herdt, Gilbert (2020). "Third Sexes and Third Genders". Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . Princeton, NJ: Princeton University Press. pp. 21–83. ISBN 978-1-942130-52-9 . Retrieved 30 July 2022 . ^ Trumbach, Randolph (1994). "London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture". In Herdt, Gilbert (ed.). Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . New York: Zone (MIT). pp. 111–136. ISBN 978-0-942299-82-3 . ^ Graham, Sharyn (April–June 2001). "Sulawesi's fifth gender" . Inside Indonesia . Archived from the original on 26 November 2014. ^ Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John ; Nieder, Timo O.; T'Sjoen, Guy (2016). "Non-binary or genderqueer genders" . International Review of Psychiatry . 28 (1): 95–102. doi : 10.3109/09540261.2015.1106446 . hdl : 1854/LU-7279758 . PMID 26753630 . S2CID 29985722 . Archived from the original on 26 June 2019 . Retrieved 9 June 2019 . ^ Ananthaswamy, Anil; Douglas, Kate. "The origins of sexism: How men came to rule 12,000 years ago" . New Scientist . Retrieved 7 March 2023 . ^ "What do we mean by "sex" and "gender"?" . World Health Organization . Archived from the original on 30 January 2017 . Retrieved 26 November 2015 . ^ Alters S, Schiff W (2009). Essential Concepts for Healthy Living . Jones & Bartlett Publishers . p. 143. ISBN 978-0-7637-5641-3 . Retrieved 3 January 2018 . ^ Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy . 21 (3): 416–438. doi : 10.1093/oxrep/gri024 . ^ Dobres, Marcia-Anne (27 November 2020). "Gender in the Earliest Human Societies" . In Meade, Teresa A.; Wiesner-Hanks, Merry E. (eds.). A Companion to Global Gender History (1 ed.). Wiley. pp. 183–204. doi : 10.1002/9781119535812.ch11 . ISBN 978-1-119-53580-5 . S2CID 229399965 . Archived from the original on 10 June 2022 . Retrieved 10 June 2022 . ^ "The Nature of Kinship: Overview" . www2.palomar.edu . Archived from the original on 3 December 2020 . Retrieved 24 October 2020 . ^ Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition" . Proceedings of the National Academy of Sciences of the United States of America . 117 (5): 2378–2384. Bibcode : 2020PNAS..117.2378I . doi : 10.1073/pnas.1917716117 . PMC 7007516 . PMID 31964846 . ^ Chandra, Kanchan (2012). Constructivist theories of ethnic politics . Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7 . OCLC 829678440 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389. In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of 'us' and 'them.' In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population. ^ Blackmore E (22 February 2019). "Race and ethnicity: How are they different?" . Culture . Archived from the original on 22 October 2020 . Retrieved 24 October 2020 . ^ Chandra K (2006). "What is Ethnic Identity and Does It Matter?" . Annual Review of Political Science . 9 (1): 397–424. doi : 10.1146/annurev.polisci.9.062404.170715 . ISSN 1094-2939 . ^ Smith AD (1999). Myths and Memories of the Nation . Oxford University Press. pp. 4–7. ^ Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism . 13 (1): 19–35. doi : 10.1111/j.1469-8129.2007.00271.x . ^ Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism . London: Sage. p. 171. ISBN 978-1-4129-0101-7 . ^ Christian D (2004). Maps of Time . University of California Press. ISBN 978-0-520-24476-4 . ^ Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?" . SAPIENS . Archived from the original on 7 August 2020 . Retrieved 24 October 2020 . ^ Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit" . Proceedings of the National Academy of Sciences of the United States of America . 115 (19): E4532–E4540. Bibcode : 2018PNAS..115E4532Z . doi : 10.1073/pnas.1708960115 . PMC 5948950 . PMID 29674447 . S2CID 4993139 . ^ Melina R (14 February 2011). "What Are the Different Types of Governments?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 24 October 2020 . ^ "Democracy Index 2021: less than half the world lives in a democracy" . The Economist Democracy Index . Economist Intelligence Unit . February 10, 2022. ^ Jeannie Evers (23 December 2012). "international organization" . National Geographic Society . Archived from the original on 27 April 2017 . Retrieved 24 October 2020 . ^ Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization . 58 (1): 1–29. doi : 10.1016/j.jebo.2004.03.009 . ISSN 0167-2681 . ^ Gibbons J (11 August 2015). "Why did Neanderthals go extinct?" . Smithsonian Insider . Archived from the original on 12 November 2020 . Retrieved 11 October 2020 . ^ University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?" . www.newswise.com . Archived from the original on 1 February 2021 . Retrieved 11 October 2020 . ^ Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years" . inews.co.uk . Archived from the original on 23 January 2021 . Retrieved 11 October 2020 . ^ Henriques M. "How spices changed the ancient world" . www.bbc.com . Archived from the original on 25 January 2021 . Retrieved 11 October 2020 . ^ Strauss IE (26 February 2016). "The Myth of the Barter Economy" . The Atlantic . Archived from the original on 15 February 2021 . Retrieved 11 October 2020 . ^ "The History of Money" . www.pbs.org . 26 October 1996. Archived from the original on 29 November 2020 . Retrieved 11 October 2020 . ^ "Why do we need economists and the study of economics?" . Federal Reserve Bank of San Francisco . July 2000. Archived from the original on 12 November 2020 . Retrieved 23 October 2020 . ^ Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong" . New Scientist . Archived from the original on 3 February 2021 . Retrieved 24 October 2020 . ^ Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates" . The Atlantic . Archived from the original on 7 May 2021 . Retrieved 7 May 2021 . ^ Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature . 538 (7624): 233–237. Bibcode : 2016Natur.538..233G . doi : 10.1038/nature19758 . PMID 27680701 . S2CID 4454927 . ^ Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF) . Nature . 538 (7624): 180–181. Bibcode : 2016Natur.538..180P . doi : 10.1038/nature19474 . PMID 27680700 . S2CID 4459560 . Archived (PDF) from the original on 20 May 2022 . Retrieved 30 July 2022 . ^ Ferguson RB (1 September 2018). "War Is Not Part of Human Nature" . Scientific American . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Ferguson N (September–October 2006). "The Next War of the World" . Foreign Affairs . Archived from the original on 25 April 2022 . Retrieved 30 July 2022 . ^ Beauchamp, Zack (June 23, 2015). "600 years of war and peace, in one amazing chart" . Vox . External links Listen to this article ( 1 hour and 16 minutes ) This audio file was created from a revision of this article dated 11 January 2022 ( 2022-01-11 ) , and does not reflect subsequent edits. ( Audio help · More spoken articles ) v t e Human evolution Taxonomy ( Hominins ) Last common ancestors Chimpanzee–human Gorilla–human Orangutan–human Gibbon–human Australopithecines Nakalipithecus Orrorin Sahelanthropus Kenyanthropus Ardipithecus A. kadabba A. ramidus Australopithecus A. afarensis A. africanus A. anamensis A. bahrelghazali A. deyiremeda A. garhi A. sediba Paranthropus P. aethiopicus P. boisei P. robustus Humans and proto-humans ( Homo ) Proto-humans H. gautengensis (?) H. habilis H. naledi H. rudolfensis (?) H. tsaichangensis (?) Homo erectus H. e. erectus H. e. georgicus H. e. lantianensis H. e. nankinensis H. e. pekinensis H. e. soloensis H. e. tautavelensis H. e. yuanmouensis Archaic humans H. antecessor Denisovans H. ergaster (?) H. floresiensis H. heidelbergensis H. longi (?) H. luzonensis H. neanderthalensis H. rhodesiensis (?) Modern humans Homo sapiens H. s. sapiens (archaic homo sapiens, anatomically modern humans) Jebel Irhoud H. s. idaltu Cro-Magnon Manot people Tam Pa Ling Red Deer Cave people Ancestors Homo habilis → Homo ergaster / Homo erectus (→ Homo antecessor ) → Homo heidelbergensis → archaic Homo sapiens → Homo sapiens Models General models Hunting Gathering Endurance running Aquatic ape Sexual selection Self-domestication Specific models Diet Cooking Expensive tissue Shore-based Drugs Drunken monkey Evolutionary models of human drug use Stoned ape theory Behavior Killer ape Cooperative eye Life history Grandmother Patriarch Topics Bipedalism Skeleton Muscles Skin color Hair Thermoregulation Speech Language Intelligence Gender roles Origin of modern humans Recent African origin Multiregional origin Archaic admixture Behavioral modernity Early migrations Recent evolution Timelines Human evolution Human prehistory Human timeline Others Theorists Books Fossils Evolutionary anthropology Paleoanthropology Human evolutionary developmental biology Category Commons Evolutionary biology Portal v t e Extant species of family Hominidae (great apes) Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Hominidae Ponginae Pongo (Orangutans) Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Homininae Gorilla (Gorillas) Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Hominini Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Homo (Humans) Human ( H. sapiens ) Category v t e Apes Extant ape species Homo Human ( H. sapiens ) Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Gorilla Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Orangutan Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Gibbon ( family : Hylobatidae) Study of apes Great ape language Dian Fossey Birutė Galdikas Jane Goodall Chimpanzee genome project Human Genome Project Gladys Kalema-Zikusoka Neanderthal genome project Willie Smits Lone Drøscher Nielsen Ian Redmond Elgin Center Iowa Primate Learning Sanctuary Borneo Orangutan Survival Primate archaeology Legal and social status Personhood Research ban Kinshasa Declaration on Great Apes Great Ape Project Great Apes Survival Partnership International Primate Day Nonhuman Rights Project Related Primate List of individual apes (non-human) Apes in space (non-human) Bigfoot Bushmeat Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor Gibbon–human last common ancestor List of fictional primates (non-human) Great apes Human evolution Monkey Day Mythic humanoids Yeren Yeti Yowie Category Humans at Wikipedia's sister projects : Definitions from Wiktionary Media from Commons Quotations from Wikiquote Texts from Wikisource Taxa from Wikispecies Taxon identifiers Homo sapiens Wikidata : Q15978631 ADW : Homo_sapiens BOLD : 12439 CoL : 6MB3T EoL : 327955 EPPO : HOMXSA GBIF : 2436436 iNaturalist : 43584 IRMNG : 10857762 ITIS : 180092 MDD : 1000718 MSW : 12100795 NBN : NHMSYS0000376773 NCBI : 9606 NZOR: d83185ac-1aa6-4f59-8645-fe8c040857b3 Observation.org : 83981 OBIS : 1455977 Open Tree of Life : 770315 Paleobiology Database : 83088 TSA : 8319 WoRMS : 1455977 ZooBank : 58D31D52-713D-44B4-9FE9-CB2D9249C422 Authority control databases International FAST National France BnF data Germany Israel Czech Republic Korea Other Encyclopedia of Modern Ukraine NARA İslâm Ansiklopedisi Retrieved from " https://en.wikipedia.org/w/index.php?title=Human&oldid=1221314650 " Categories : Hominini Humans Apex predators Mammals described in 1758 Taxa named by Carl Linnaeus Tool-using mammals Cosmopolitan mammals Hidden categories: CS1 maint: DOI inactive as of March 2024 Articles with short description Short description is different from Wikidata Good articles Wikipedia indefinitely semi-protected pages Wikipedia indefinitely move-protected pages Articles with 'species' microformats Articles containing Latin-language text Articles containing Old French (842-ca. 1400)-language text Articles containing French-language text Articles containing potentially dated statements from 2018 All articles containing potentially dated statements Articles with hAudio microformats Spoken articles Pages using Sister project links with wikidata mismatch Pages using Sister project links with default search Taxonbars desynced from Wikidata Taxonbars on possible non-taxon pages Taxonbars with 20–24 taxon IDs Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with GND identifiers Articles with J9U identifiers Articles with NKC identifiers Articles with NLK identifiers Articles with EMU identifiers Articles with NARA identifiers Articles with TDVİA identifiers Articles containing video clips
Species of hominid in the genus Homo Several terms redirect here. For other uses, see Human (disambiguation) , Mankind (disambiguation) , Humankind (disambiguation) , Human Race (disambiguation) , Human Being (disambiguation) , and Homo sapiens (disambiguation) . Human Temporal range: 0.3–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Chibanian – present Male (left) and female (right) adult humans, Thailand , 2007 Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Infraorder: Simiiformes Family: Hominidae Subfamily: Homininae Tribe: Hominini Genus: Homo Species: H. sapiens Binomial name Homo sapiens Linnaeus , 1758 Homo sapiens population density (2005) Humans ( Homo sapiens ) or modern humans are the most common and widespread species of primate , and the last surviving species of the genus Homo . They are great apes characterized by their hairlessness , bipedalism , and high intelligence . Humans have large brains , enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools , and form complex social structures and civilizations . Humans are highly social , with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states . As such, social interactions between humans have established a wide variety of values, social norms , languages , and traditions (collectively termed institutions ), each of which bolsters human society . Humans are also highly curious : the desire to understand and influence phenomena has motivated humanity's development of science , technology , philosophy , mythology , religion , and other frameworks of knowledge ; humans also study themselves through such domains as anthropology , social science , history , psychology , and medicine . As of April 2024, there are estimated to be more than 8 billion humans alive . Although some scientists equate the term "humans" with all members of the genus Homo , in common usage it generally refers to Homo sapiens , the only extant member. All other members of the genus Homo , which are now extinct, are known as archaic humans , and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa , they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence , interbreeding with Homo sapiens , or inability to adapt to climate change. For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution , which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement ; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change . Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle. Genes and the environment influence human biological variation in visible characteristics, physiology , disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic : generally, males have greater body strength and females have a higher body fat percentage. At puberty , humans develop secondary sex characteristics . Females are capable of pregnancy , usually between puberty, at around 12 years old, and menopause , around the age of 50. Humans are omnivorous , capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus . Humans can survive for up to eight weeks without food and several days without water . Humans are generally diurnal , sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death . Often, both the mother and the father provide care for their children, who are helpless at birth . Humans have a large, highly developed, and complex prefrontal cortex , the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory ; they have flexible facial expressions, self-awareness , and a theory of mind . The human mind is capable of introspection , private thought , imagination , volition , and forming views on existence . This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language . Etymology and definition Further information: Names for the human species and Human taxonomy Carl Linnaeus coined the name Homo sapiens All modern humans are classified into the species Homo sapiens , coined by Carl Linnaeus in his 1735 work Systema Naturae . The generic name " Homo " is a learned 18th-century derivation from Latin homō , which refers to humans of either sex. The word human can refer to all members of the Homo genus. The name " Homo sapiens " means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals , should be included as a separate species of humans or as a subspecies of H. sapiens . Human is a loanword of Middle English from Old French humain , ultimately from Latin hūmānus , the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity ) as well as to human males. It may also refer to individuals of either sex. Despite the fact that the word animal is colloquially used as an antonym for human , and contrary to a common biological misconception , humans are animals. The word person is often used interchangeably with human , but philosophical debate exists as to whether personhood applies to all humans or all sentient beings , and further if one can lose personhood (such as by going into a persistent vegetative state ). Evolution Main article: Human evolution Humans are apes ( superfamily Hominoidea ). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo ), then gorillas (genus Gorilla ), and finally, chimpanzees and bonobos (genus Pan ). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct. Reconstruction of Lucy , the first Australopithecus afarensis skeleton found The genus Homo evolved from Australopithecus . Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus . The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia , and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster ) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan . Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis , the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier. The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second ( Southern Dispersal ) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii , Easter Island , Madagascar , and New Zealand in the years 300 to 1280 CE. Human evolution was not a simple linear or branched progression but involved interbreeding between related species . Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans , may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans. Human evolution is characterized by a number of morphological , developmental , physiological , and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees . The most significant of these adaptations are hairlessness , obligate bipedalism, increased brain size and decreased sexual dimorphism ( neoteny ). The relationship between all these changes is the subject of ongoing debate. Hominoidea (hominoids, apes ) Hylobatidae ( gibbons ) Hominidae (hominids, great apes ) Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans) History Main article: Human history Prehistory Main article: Prehistory Overview map of the peopling of the world by early human migration during the Upper Paleolithic , following the Southern Dispersal paradigm Until about 12,000 years ago, all humans lived as hunter-gatherers . The Neolithic Revolution (the invention of agriculture ) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea , and the Sahel and West Savanna regions of Africa. Access to food surplus led to the formation of permanent human settlements , the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations . Ancient Main article: Ancient history Great Pyramids of Giza , Egypt An urban revolution took place in the 4th millennium BCE with the development of city-states , particularly Sumerian cities located in Mesopotamia . It was in these cities that the earliest known form of writing, cuneiform script , appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation . They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture , Minoans and the Shang dynasty , rose to prominence in new areas. The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages . During this period iron started replacing bronze, leading to the Iron Age . In the 5th century BCE, history started being recorded as a discipline , which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars . In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire 's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions. Medieval Main article: Post-classical history Medieval French manuscript illustration of the three classes of medieval society from the 13th-century Li Livres dou Santé Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages . During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age , inspiring achievements in architecture , the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England , the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims . In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast . Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific. Modern Main articles: Early modern period and Late modern period James Watt 's steam engine The early modern period in Europe and the Near East ( c. 1450 –1800) began with the final defeat of the Byzantine Empire , and the rise of the Ottoman Empire . Meanwhile, Japan entered the Edo period , the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance , starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas . This expansion led to the Atlantic slave trade and the genocide of Native American peoples . This period also marked the Scientific Revolution , with great advances in mathematics , mechanics , astronomy and physiology . The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology , major innovations in transport and energy development . The United States of America underwent great change, going from a small group of colonies to one of the global superpowers . The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World , while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania. A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War , one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War , involving almost all of the world's countries . The war's destruction led to the collapse of most global empires, leading to widespread decolonization. Contemporary Main article: Contemporary history Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race , ending in the collapse of the Soviet Union. The current Information Age , spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected. Habitat and population Further information: Human geography and Demography Population statistics Choropleth showing Population density (people per square kilometer) estimates by 30 arc-second grid in 2020 World population 8.1 billion Population density 16/km (41/sq mi) by total area 54/km (140/sq mi) by land area Largest cities Tokyo , Delhi , Shanghai , São Paulo , Mexico City , Cairo , Mumbai , Beijing , Dhaka , Osaka , New York - Newark , Karachi , Buenos Aires , Chongqing , Istanbul , Kolkata , Manila , Lagos , Rio de Janeiro , Tianjin , Kinshasa , Guangzhou , Los Angeles - Long Beach - Santa Ana , Moscow , Shenzhen , Lahore , Bangalore , Paris , Jakarta , Chennai , Lima , Bogota , Bangkok , London Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence , such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation , urban planning , construction, deforestation and desertification . Human settlements continue to be vulnerable to natural disasters , especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics , increasing knowledge or enhancing the exchange of resources. Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms , although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa , India , Russia , Australia , Fiji , United States and Brazil (each located in a different biogeographical realm). By using advanced tools and clothing , humans have been able to extend their tolerance to a wide variety of temperatures, humidities , and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest , arid desert , extremely cold arctic regions , and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth 's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%). Within the last century, humans have explored challenging environments such as Antarctica, the deep sea , and outer space . Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific , military , or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft . Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station . Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%. Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues , first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals. In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums . Humans have had a dramatic effect on the environment . They are apex predators , being rarely preyed upon by other species. Human population growth , industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life. Biology Anatomy and physiology Main article: Human body Basic anatomical features of female and male humans. These models have had body hair and male facial hair removed and head hair trimmed. Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.3 2.1.2.3 . Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth . Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars , with some individuals having them congenitally absent. Humans share with chimpanzees a vestigial tail, appendix , flexible shoulder joints, grasping fingers and opposable thumbs . Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling , hearing and digesting proteins . While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair , most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet. It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged . Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals. Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger. Genetics Main article: Human genetics A graphical representation of the standard human karyotype , including both the female (XX) and male (XY) sex chromosomes. Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes , each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes . Like other mammals, humans have an XY sex-determination system , so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood. While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years. The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms . African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas . By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA , which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve , must have lived around 90,000 to 200,000 years ago. Life cycle See also: Childbirth and Life expectancy A 10 mm human embryo at 5 weeks Most human reproduction takes place by internal fertilization via sexual intercourse , but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus . Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions. Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries. Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth , humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy , childhood , adolescence , adulthood and old age . The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis ), rather than by continuing to bear children into old age. The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018 , the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic , it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world , the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide. Human life stages Infant boy and girl Boy and girl before puberty ( children ) Adolescent male and female Adult man and woman Elderly man and woman Diet Main article: Human nutrition Humans living in Bali , Indonesia , preparing a meal Humans are omnivorous , capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous . In some cases, dietary restrictions in humans can lead to deficiency diseases ; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science . Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game , which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus . Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture , a gradual process called the Neolithic Revolution . These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture. In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation . Childhood malnutrition is also common and contributes to the global burden of disease . However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries . Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an " obesity epidemic ." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet. Biological variation Main article: Human genetic variation A Libyan , a Nubian , a Syrian , and an Egyptian , drawing by an unknown artist after a mural of the tomb of Seti I There is biological variation in the human species – with traits such as blood type , genetic diseases , cranial features , facial features , organ systems , eye color , hair color and texture , height and build , and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin , and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet , exercise, and sleep patterns . A variety of human hair colors; from top left, clockwise: black , brown , blonde , white , red . There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk . Sickle cell anemia , which may provide increased resistance to malaria , is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions , tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes . Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau . Human hair ranges in color from red to blond to brown to black , which is the most frequent. Hair color depends on the amount of melanin , with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach , or even nearly white or colorless in cases of albinism . It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D , which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation. There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other. Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa , and particularly West Africa , have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans. Humans are a gonochoric species, meaning they are divided into male and female sexes . The greatest degree of genetic variation exists between males and females . While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation . As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare. Psychology Main article: Psychology Drawing of the human brain , showing several important structures The human brain , the focal point of the central nervous system in humans, controls the peripheral nervous system . In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion , it is also the locus of "higher" order functioning such as thought , reasoning , and abstraction . These cognitive processes constitute the mind , and, along with their behavioral consequences, are studied in the field of psychology . Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition . This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to. There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in " mental time travel ". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind . Sleep and dreaming Main articles: Sleep and Dream Humans are generally diurnal . The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort. During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep . The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming , where the dreamer is self-aware . Dreams can at times make a creative thought occur or give a sense of inspiration . Consciousness and thought Main articles: Consciousness and Cognition Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection , private thought , imagination and volition . It now often includes some kind of experience , cognition , feeling or perception . It may be 'awareness', or ' awareness of awareness ', or self-awareness . There might be different levels or orders of consciousness , or different kinds of consciousness, or just one kind with different features. The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses , and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition , the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development . Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population. Motivation and emotion Main articles: Motivation and Emotion Illustration of grief from Charles Darwin 's 1872 book The Expression of the Emotions in Man and Animals Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization . Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure . They are often intertwined with mood , temperament , personality , disposition , creativity , and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal. Emotional experiences perceived as pleasant , such as joy , interest or contentment , contrast with those perceived as unpleasant , like anxiety , sadness , anger , and despair . Happiness , or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects , while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life . Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted. Sexuality and love Main articles: Human sexuality and Love Human parents often display familial love for their children. For humans, sexuality involves biological , erotic , physical , emotional , social , or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions , including the human sexual response cycle . Sexuality also affects and is affected by cultural, political, legal, philosophical, moral , ethical , and religious aspects of life. Sexual desire, or libido , is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often. Humans can fall anywhere along a continuous scale of sexual orientation , although most humans are heterosexual . While homosexual behavior occurs in some other animals , only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation , as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well. Love most commonly refers to a feeling of strong attraction or emotional attachment . It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine , norepinephrine , serotonin and other chemicals stimulate the brain's pleasure center , leading to side effects such as increased heart rate , loss of appetite and sleep , and an intense feeling of excitement . Culture Main articles: Culture and Cultural universal Human society statistics Most widely spoken languages English , Mandarin Chinese , Hindi , Spanish , Standard Arabic , Bengali , French , Russian , Portuguese , Urdu Most practiced religions Christianity , Islam , Hinduism , Buddhism , folk religions , Sikhism , Judaism , unaffiliated Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the " folk physics " required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning . Language Main article: Language Principal language families of the world (and in some cases geographic groups of families). For greater detail, see Distribution of languages in the world . While many species communicate , language is unique to humans, a defining feature of humanity, and a cultural universal . Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement , using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors. Language differs from other forms of communication in that it is modality independent ; the same meanings can be conveyed through different media, audibly in speech , visually by sign language or writing, and through tactile media such as braille . Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct . The arts Main article: The arts Human arts can take many forms including visual , literary , and performing . Visual art can range from paintings and sculptures to film , fashion design , and architecture . Literary arts can include prose , poetry , and dramas . The performing arts generally involve theatre , music , and dance . Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation , video games , and medicine . As well as providing entertainment and transferring knowledge, the arts are also used for political purposes . The Deluge tablet of the Gilgamesh epic in Akkadian Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage. Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures . There exists a wide variety of music genres and ethnic musics ; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment . Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain. Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh , first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation. Tools and technologies Main articles: Tool and Technology The SCMaglev , the fastest train in the world clocking in at 603 km/h (375 mph) as of 2015 Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated , thus proving essential in the development of agriculture – what is known as the Neolithic Revolution . China developed paper , the printing press , gunpowder , the compass and other important inventions . The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel , which is used in railways , skyscrapers and many other products. This coincided with the Industrial Revolution , where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially , with major innovations in the 20th century including: electricity , penicillin , semiconductors , internal combustion engines , the Internet , nitrogen fixing fertilisers , airplanes , computers , automobiles , contraceptive pills , nuclear fission , the green revolution , radio , scientific plant breeding , rockets , air conditioning , television and the assembly line . Religion and spirituality Main articles: Religion and Spirituality Shango , the Orisha of fire, lightning, and thunder, in the Yoruba religion , depicted on horseback Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural , sacred or divine , and practices, values , institutions and rituals associated with such belief. Some religions also have a moral code . The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago ). It may have evolved to play a role in helping enforce and encourage cooperation between humans. Religion manifests in diverse forms. Religion can include a belief in life after death , the origin of life , the nature of the universe ( religious cosmology ) and its ultimate fate ( eschatology ), and moral or ethical teachings . Views on transcendence and immanence vary substantially; traditions variously espouse monism , deism , pantheism , and theism (including polytheism and monotheism ). Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims , Hindus and Buddhists . As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious , including those with no religious beliefs or no identity with any religion. Science and philosophy Main articles: Science and Philosophy The Dunhuang map , a star map showing the North Polar region. China circa 700. An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy. Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period . Other early advances in science came from the Han dynasty in China and during the Islamic Golden Age . The scientific revolution , near the end of the Renaissance , led to the emergence of modern science . A chain of events and influences led to the development of the scientific method , a process of observation and experimentation that is used to differentiate science from pseudoscience . An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition . All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics ), which are concerned with formal systems , the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics , chemistry , biology ) and social sciences (e.g., psychology , economics, sociology). Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics , epistemology , logic , and axiology (which includes ethics and aesthetics ). Society Main article: Society Humans often live in family-based social structures Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power , reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies . Gender Main article: Gender Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex . The most common categorisation is a gender binary of men and women . Some societies recognise a third gender , or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female. Gender roles are often associated with a division of norms , practices , dress , behavior , rights , duties , privileges , status , and power , with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct , gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic , while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal. Kinship Main article: Kinship All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants ( consanguinity ), and relations through marriage ( affinity ). There is also a third type applied to godparents or adoptive children ( fictive ). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance . All societies have rules of incest taboo , according to which marriage between certain kinds of kin relations is prohibited, and some also have rules of preferential marriage with certain kin relations. Ethnicity Main article: Ethnic group Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry , language , history , society , culture , nation , religion , or social treatment within their residing area. Ethnicity is separate from the concept of race , which is based on physical characteristics, although both are socially constructed . Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries. Government and politics Main articles: Government and Politics The United Nations headquarters in New York City, which houses one of the world's largest political organizations As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances. Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy , 17% in a hybrid regime , and 37% in an authoritarian regime . Many countries belong to international organizations and alliances ; the largest of these is the United Nations , with 193 member states . Trade and economics Main articles: Trade and Economics The Silk Road (red) and spice trade routes (blue) Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian . The first truly international trade routes were around the spice trade through the Roman and medieval periods. Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities ; the oldest being in the form of cattle and the most widely used being cowrie shells . Money has since evolved into governmental issued coins , paper and electronic money . Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population. Conflict Main article: Conflict (process) American troops landing at Normandy , WWII. Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered , rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations, with rates of homicide about 0.01% in societies that have legal systems and strong cultural attitudes against violence. The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war ) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict. See also Mammals portal Evolutionary biology portal Science portal List of human evolution fossils Timeline of human evolution Notes ^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects. ^ Cities with over 10 million inhabitants as of 2018. ^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that. References ^ Groves CP (2005). Wilson DE , Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4 . OCLC 62265494 . ^ Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences . 149 (1): 109–114. JSTOR 4065043 . ^ Porkorny (1959). IEW . s.v. "g'hðem" pp. 414–116. ^ "Homo" . Dictionary.com Unabridged (v 1.1) . Random House. 23 September 2008. Archived from the original on 27 September 2008. ^ Barras, Colin (11 January 2016). "We don't know which species should be classed as 'human' " . BBC . Archived from the original on 26 August 2021 . Retrieved 31 March 2021 . ^ Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758" . Proceedings of the Academy of Natural Sciences of Philadelphia . 149 : 109–114. ISSN 0097-3157 . JSTOR 4065043 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . ^ OED . s.v. "human". ^ "Man" . Merriam-Webster Dictionary . Archived from the original on 22 September 2017 . Retrieved 14 September 2017 . Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination ^ "Thesaurus results for human" . Merriam-Webster Dictionary . Archived from the original on 28 June 2022 . Retrieved 21 May 2022 . ^ "Misconceptions about evolution – Understanding Evolution" . University of California, Berkeley . 19 September 2021. Archived from the original on 6 June 2022 . Retrieved 21 May 2022 . ^ "Concept of Personhood" . University of Missouri School of Medicine . Archived from the original on 4 March 2021 . Retrieved 4 July 2021 . ^ Tuttle RH (4 October 2018). "Hominoidea: conceptual history" . In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology . Hoboken , New Jersey , United States : John Wiley & Sons, Inc. pp. 1–2. doi : 10.1002/9781118584538.ieba0246 . ISBN 978-1-118-58442-2 . S2CID 240125199 . Retrieved 26 May 2021 . ^ Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution . 30 (3): 260–266. Bibcode : 1990JMolE..30..260G . doi : 10.1007/BF02099995 . PMID 2109087 . S2CID 2112935 . ^ Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets" . Molecular Biology and Evolution . 14 (3): 248–265. doi : 10.1093/oxfordjournals.molbev.a025761 . PMID 9066793 . ^ MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes" . Evolution pages . Archived from the original on 9 August 2011 . Retrieved 18 May 2006 . ^ McNulty, Kieran P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?" . Nature Education Knowledge . Archived from the original on 10 January 2016 . Retrieved 11 June 2022 . ^ Strait DS (September 2010). "The Evolutionary History of the Australopiths" . Evolution: Education and Outreach . 3 (3): 341–352. doi : 10.1007/s12052-010-0249-6 . ISSN 1936-6434 . S2CID 31979188 . ^ Dunsworth HM (September 2010). "Origin of the Genus Homo" . Evolution: Education and Outreach . 3 (3): 353–366. doi : 10.1007/s12052-010-0247-8 . ISSN 1936-6434 . S2CID 43116946 . ^ Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1698): 20150248. doi : 10.1098/rstb.2015.0248 . PMC 4920303 . PMID 27298460 . S2CID 20267830 . ^ Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia" . Science . 347 (6228): 1352–1355. Bibcode : 2015Sci...347.1352V . doi : 10.1126/science.aaa1343 . PMID 25739410 . ^ Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature . 559 (7715): 608–612. Bibcode : 2018Natur.559..608Z . doi : 10.1038/s41586-018-0299-4 . PMID 29995848 . S2CID 49670311 . ^ Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF) . Nature . 546 (7657): 289–292. Bibcode : 2017Natur.546..289H . doi : 10.1038/nature22336 . PMID 28593953 . S2CID 256771372 . Archived (PDF) from the original on 8 January 2020 . Retrieved 30 July 2022 . ^ "Out of Africa Revisited". Science (This Week in Science ). 308 (5724): 921. 13 May 2005. doi : 10.1126/science.308.5724.921g . ISSN 0036-8075 . S2CID 220100436 . ^ Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature . 423 (6941): 692–693, 695. Bibcode : 2003Natur.423..692S . doi : 10.1038/423692a . PMID 12802315 . S2CID 26693109 . ^ Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?" . actionbioscience . Washington, DC: American Institute of Biological Sciences . Archived from the original on 17 June 2021 . Retrieved 23 November 2009 . ^ Marean, Curtis; et al. (2007). "Early human use of marine resources and pigment in South Africa during the Middle Pleistocene" (PDF) . Nature . 449 (7164): 905–908. Bibcode : 2007Natur.449..905M . doi : 10.1038/nature06204 . PMID 17943129 . S2CID 4387442 . Archived (PDF) from the original on 2023-05-25 . Retrieved 2023-01-07 . ^ Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB (2018). "Long-distance stone transport and pigment use in the earliest Middle Stone Age" . Science . 360 (6384): 90–94. Bibcode : 2018Sci...360...90B . doi : 10.1126/science.aao2646 . PMID 29545508 . ^ Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology . 26 (6): 827–833. Bibcode : 2016CBio...26..827P . doi : 10.1016/j.cub.2016.01.037 . hdl : 2440/114930 . PMID 26853362 . S2CID 140098861 . ^ Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture" . Genome Research . 25 (4): 459–466. doi : 10.1101/gr.186684.114 . PMC 4381518 . PMID 25770088 . ^ Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia" . Science . 331 (6016): 453–456. Bibcode : 2011Sci...331..453A . doi : 10.1126/science.1199113 . PMID 21273486 . S2CID 20296624 . Archived from the original on 27 April 2011 . Retrieved 1 May 2011 . ^ Rincon P (27 January 2011). "Humans 'left Africa much earlier' " . BBC News . Archived from the original on 9 August 2012. ^ Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature . 547 (7663): 306–310. Bibcode : 2017Natur.547..306C . doi : 10.1038/nature22968 . hdl : 2440/107043 . PMID 28726833 . S2CID 205257212 . ^ Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF) . University of Waikato . Archived (PDF) from the original on 22 May 2010 . Retrieved 29 April 2010 . ^ Appenzeller T (May 2012). "Human migrations: Eastern odyssey" . Nature . 485 (7396): 24–26. Bibcode : 2012Natur.485...24A . doi : 10.1038/485024a . PMID 22552074 . ^ Reich D , Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" . Nature . 468 (7327): 1053–1060. Bibcode : 2010Natur.468.1053R . doi : 10.1038/nature09710 . hdl : 10230/25596 . PMC 4306417 . PMID 21179161 . ^ Hammer MF (May 2013). "Human Hybrids" (PDF) . Scientific American . 308 (5): 66–71. Bibcode : 2013SciAm.308e..66H . doi : 10.1038/scientificamerican0513-66 . PMID 23627222 . Archived from the original (PDF) on 24 August 2018. ^ Yong E (July 2011). "Mosaic humans, the hybrid species" . New Scientist . 211 (2823): 34–38. Bibcode : 2011NewSc.211...34Y . doi : 10.1016/S0262-4079(11)61839-3 . ^ Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology . 43 (1): 1–11. doi : 10.1007/s11692-015-9348-1 . S2CID 14329491 . ^ Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans" . Genome Research . 20 (5): 547–553. doi : 10.1101/gr.076000.108 . PMC 2860157 . PMID 20439435 . ^ Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans" . Science . 334 (6052): 89–94. Bibcode : 2011Sci...334...89A . doi : 10.1126/science.1209202 . PMC 3677943 . PMID 21868630 . ^ Sandel, Aaron A. (30 July 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness" . American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . Archived from the original on 22 July 2023 . Retrieved 22 July 2023 . ^ Boyd R , Silk JB (2003). How Humans Evolved . New York: Norton . ISBN 978-0-393-97854-4 . ^ Little, Michael A.; Blumler, Mark A. (2015). "Hunter-Gatherers" . In Muehlenbein, Michael P. (ed.). Basics in Human Evolution . Boston: Academic Press. pp. 323–335. ISBN 978-0-12-802652-6 . Archived from the original on 3 July 2022 . Retrieved 30 July 2022 . ^ Scarre, Chris (2018). "The world transformed: from foragers and farmers to states and empires". In Scarre, Chris (ed.). The Human Past: World Prehistory and the Development of Human Societies (4th ed.). London: Thames & Hudson . pp. 174–197. ISBN 978-0-500-29335-5 . ^ Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe . Walnut Creek, CA: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5 . OCLC 855969933 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society . Elsevier. pp. 103–131. doi : 10.1016/B978-0-12-805247-1.00006-X . ISBN 978-0-12-805247-1 . ^ He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China" . The Holocene . 27 (12): 1885–1898. Bibcode : 2017Holoc..27.1885H . doi : 10.1177/0959683617708455 . S2CID 133660098 . Archived from the original on 20 November 2021 . Retrieved 30 July 2022 . ^ Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago" . Proceedings of the National Academy of Sciences of the United States of America . 106 (18): 7367–7372. Bibcode : 2009PNAS..106.7367L . doi : 10.1073/pnas.0900158106 . PMC 2678631 . PMID 19383791 . ^ Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea" . Science . 301 (5630): 189–193. doi : 10.1126/science.1085255 . PMID 12817084 . S2CID 10644185 . ^ Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication" . Science Advances . 5 (5): eaaw1947. Bibcode : 2019SciA....5.1947S . doi : 10.1126/sciadv.aaw1947 . PMC 6527260 . PMID 31114806 . ^ Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF) . Current Anthropology . 58 (5): 673–683. doi : 10.1086/693898 . S2CID 149402650 . Archived (PDF) from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science . 38 (2): 312–322. Bibcode : 2011JArSc..38..312M . doi : 10.1016/j.jas.2010.09.007 . ^ Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries . Cengage Learning. ISBN 978-1-285-66153-7 . Archived from the original on 27 February 2021 . Retrieved 11 July 2015 . ^ Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500 . Cenpage Learning. ISBN 978-1-285-98299-1 . Archived from the original on 10 August 2023 . Retrieved 11 July 2015 . ^ Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization . San Francisco: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3 . Archived from the original on 10 August 2023 . Retrieved 30 July 2022 . ^ Garfinkle, Steven J. (2013). "Ancient Near Eastern City-States". In Peter Fibiger Bang ; Walter Scheidel (eds.). The Oxford Handbook of the State in the Ancient Near East and Mediterranean . Oxford Academic. pp. 94–119. doi : 10.1093/oxfordhb/9780195188318.013.0004 . ISBN 978-0-19-518831-8 . ^ Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi : 10.1002/9781119193814.ch2 . ISBN 978-1-119-19329-6 . S2CID 216180781 . ^ Robinson A (October 2015). "Ancient civilization: Cracking the Indus script" . Nature . 526 (7574): 499–501. Bibcode : 2015Natur.526..499R . doi : 10.1038/526499a . PMID 26490603 . S2CID 4458743 . ^ Crawford H (2013). "Trade in the Sumerian world". The Sumerian World . Routledge. pp. 447–461. ISBN 978-1-136-21911-5 . ^ Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles" . Acta Archaeologica Academiae Scientiarum Hungaricae . 69 (2): 271–298. doi : 10.1556/072.2018.69.2.3 . ISSN 0001-5210 . S2CID 115685157 . Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Pryor FL (1985). "The Invention of the Plow" . Comparative Studies in Society and History . 27 (4): 727–743. doi : 10.1017/S0010417500011749 . ISSN 0010-4175 . JSTOR 178600 . S2CID 144840498 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Carter R (2012). "19. Watercraft ". In Potts DT (ed.). A companion to the archaeology of the ancient Near East . Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0 . Archived from the original on 28 April 2015 . Retrieved 8 February 2014 . ^ Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction . CUP Archive. p. 1. ISBN 978-0-521-40340-5 . ^ Robson E (2008). Mathematics in ancient Iraq: A social history . Princeton University Press. pp. xxi. ^ Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza" . Technology and Culture . 44 (2): 340–354. doi : 10.1353/tech.2003.0063 . ISSN 0040-165X . JSTOR 25148110 . S2CID 109998651 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Voosen P (August 2018). "New geological age comes under fire". Science . 361 (6402): 537–538. Bibcode : 2018Sci...361..537V . doi : 10.1126/science.361.6402.537 . PMID 30093579 . S2CID 51954326 . ^ Saggs HW (2000). Babylonians . Univ of California Press. p. 7. ISBN 978-0-520-20222-1 . ^ Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory . 12 (4): 335–364. doi : 10.1007/s10816-005-8460-4 . ISSN 1573-7764 . S2CID 53393440 . ^ Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans" . Nature . 548 (7666): 214–218. Bibcode : 2017Natur.548..214L . doi : 10.1038/nature23310 . PMC 5565772 . PMID 28783727 . ^ Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC . Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8 . ^ Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change . 6 (4): 369–382. Bibcode : 2015WIRCC...6..369K . doi : 10.1002/wcc.345 . S2CID 128460316 . ^ Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science . 39 (6): 1862–1870. Bibcode : 2012JArSc..39.1862D . doi : 10.1016/j.jas.2012.01.029 . ^ Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory . Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi : 10.1007/978-1-4419-6633-9_11 . ISBN 978-1-4419-6633-9 . ^ Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography . United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1 . ^ Beard M (2 October 2015). "Why ancient Rome matters to the modern world" . The Guardian . Archived from the original on 14 April 2021 . Retrieved 17 April 2021 . ^ Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece" . Stanford University . Archived from the original on 18 April 2021 . Retrieved 17 April 2021 . ^ Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature . 582 (7813): 530–533. Bibcode : 2020Natur.582..530I . doi : 10.1038/s41586-020-2343-4 . PMID 32494009 . S2CID 219281856 . ^ Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar" . Latin American Antiquity . 28 (1): 88–104. doi : 10.1017/laq.2016.4 . ISSN 1045-6635 . S2CID 164417025 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida" . Proceedings of the Seminar for Arabian Studies . 46 : 25–40. ISSN 0308-8421 . JSTOR 45163415 . Archived from the original on 28 April 2022 . Retrieved 30 July 2022 . ^ Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration . 21 (1): 25–86. doi : 10.1080/01900699808525297 . ISSN 0190-0692 . ^ Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age" . Journal of the American Oriental Society . 96 (1): 15–26. doi : 10.2307/599886 . ISSN 0003-0279 . JSTOR 599886 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty" . Architectural History . 63 : 1–36. doi : 10.1017/arh.2020.1 . ISSN 0066-622X . S2CID 229716130 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question" . Climate . 6 (4): 90. Bibcode : 2018Clim....6...90M . doi : 10.3390/cli6040090 . ^ Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World . New York: Oxford University Press. p. 72. ISBN 978-0-19-532819-6 . Retrieved 30 July 2022 . ^ Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies . International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi : 10.1007/978-3-319-24774-8_2 . ISBN 978-3-319-24774-8 . ^ Vidal-Nanquet P (1987). The Harper Atlas of World History . Harper & Row Publishers. p. 76. ^ Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land . Simon and Schuster. ISBN 978-1-84983-770-5 . ^ Adam King (2002). "Mississippian Period: Overview" . New Georgia Encyclopedia . Archived from the original on 19 August 2009 . Retrieved 15 November 2009 . ^ Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism . Cambridge University Press. p. 2. ISBN 0-521-31896-3 . ^ May T (2013). The Mongol Conquests in World History . Reaktion Books. p. 7. ISBN 978-1-86189-971-2 . ^ Canós-Donnay S (25 February 2019). "The Empire of Mali" . Oxford Research Encyclopedia of African History . Oxford University Press. doi : 10.1093/acrefore/9780190277734.013.266 . ISBN 978-0-19-027773-4 . Archived from the original on 20 October 2021 . Retrieved 7 May 2021 . ^ Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity" . Asian Perspectives . 37 (2): 135–164. ^ Kafadar C (1 January 1994). "Ottomans and Europe" . In Brady T, Oberman T, Tracy JD (eds.). Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation . Brill. pp. 589–635. doi : 10.1163/9789004391659_019 . ISBN 978-90-04-39165-9 . Archived from the original on 2 May 2022 . Retrieved 17 April 2021 . ^ Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan" . Oxford Research Encyclopedia of Asian History . Oxford University Press. doi : 10.1093/acrefore/9780190277727.013.72 . ISBN 978-0-19-027772-7 . Archived from the original on 12 August 2021 . Retrieved 7 May 2021 . ^ Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing" . Pacific Affairs . 83 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526–1857)" . Al-Ta Lim Journal . 23 (2): 128–138. doi : 10.15548/jt.v23i2.228 . ISSN 2355-7893 . Archived from the original on 7 April 2022 . Retrieved 30 July 2022 . ^ Kirkpatrick R (2002). The European Renaissance, 1400–1600 . Routledge. p. 1. ISBN 978-1-317-88646-4 . OCLC 893909816 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Arnold D (2002). The Age of Discovery, 1400–1600 (Second ed.). Routledge. pp. xi. ISBN 978-1-136-47968-7 . OCLC 859536800 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics" . Theoretical Inquiries in Law . 11 (1). doi : 10.2202/1565-3404.1239 . ISSN 1565-3404 . S2CID 56216309 . Archived from the original on 26 August 2021 . Retrieved 30 July 2022 . ^ Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews . 20 (1–3): 277–299. Bibcode : 2001QSRv...20..277J . doi : 10.1016/S0277-3791(00)00116-5 . ^ Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature" . The Journal of African History . 30 (3): 365–394. doi : 10.1017/S0021853700024439 . ISSN 0021-8537 . JSTOR 182914 . S2CID 161321949 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide . London: Palgrave Macmillan UK. pp. 273–295. doi : 10.1057/9780230297784_11 . ISBN 978-0-230-29778-4 . ^ Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour . 38 (3–4): 157–158. doi : 10.1016/j.endeavour.2014.10.001 . PMID 25457642 . ^ "Greatest Engineering Achievements of the 20th Century" . National Academy of Engineering . Archived from the original on 6 April 2015 . Retrieved 7 April 2015 . ^ Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776 . New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0 . OCLC 299054528 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815" . Journal of Global History . 1 (1): 123–149. doi : 10.1017/S1740022806000076 . ISSN 1740-0228 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Zimmerman AF (November 1931). "Spain and Its Colonies, 1808–1820" . The Hispanic American Historical Review . 11 (4): 439–463. doi : 10.2307/2506251 . JSTOR 2506251 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ David S (2011). "British History in depth: Slavery and the 'Scramble for Africa' " . BBC . Archived from the original on 24 March 2022 . Retrieved 5 May 2021 . ^ Raudzens G (2004). "The Australian Frontier Wars, 1788–1838 (review)" . The Journal of Military History . 68 (3): 957–959. doi : 10.1353/jmh.2004.0138 . ISSN 1543-7795 . S2CID 162259092 . ^ Clark CM (2012). "Polarization of Europe, 1887–1907". The sleepwalkers : how Europe went to war in 1914 . London: Allen Lane. ISBN 978-0-7139-9942-6 . OCLC 794136314 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Robert Dahl (1989). Democracy and Its Critics . Yale UP. pp. 239–240 . ISBN 0-300-15355-4 . ^ McDougall WA (May 1985). "Sputnik, the space race, and the Cold War" . Bulletin of the Atomic Scientists . 41 (5): 20–25. Bibcode : 1985BuAtS..41e..20M . doi : 10.1080/00963402.1985.11455962 . ISSN 0096-3402 . ^ Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?" . Journal of Peace Research . 30 (2): 163–179. doi : 10.1177/0022343393030002004 . ISSN 0022-3433 . S2CID 5482851 . Archived from the original on 21 February 2022 . Retrieved 30 July 2022 . ^ Sachs JD (April 2017). "Globalization – In the Name of Which Freedom?" . Humanistic Management Journal . 1 (2): 237–252. doi : 10.1007/s41463-017-0019-5 . ISSN 2366-603X . S2CID 133030709 . ^ "World" . The World Factbook . CIA . 17 May 2016. Archived from the original on 26 January 2021 . Retrieved 2 October 2016 . ^ "World Population Prospects: The 2017 Revision" (PDF) . United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17. Archived (PDF) from the original on 26 June 2019 . Retrieved 30 July 2022 . ^ "The World's Cities in 2018" (PDF) . United Nations . Archived (PDF) from the original on 1 November 2018. ^ Rector RK (2016). The Early River Valley Civilizations (First ed.). New York: Rosen Publishing. p. 10. ISBN 978-1-4994-6329-3 . OCLC 953735302 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ "How People Modify the Environment" (PDF) . Westerville City School District . Archived (PDF) from the original on 25 February 2021 . Retrieved 13 March 2019 . ^ "Natural disasters and the urban poor" (PDF) . World Bank . October 2003. Archived (PDF) from the original on 9 August 2017. ^ Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities . [London]: Routledge. pp. x. ISBN 978-1-135-01559-6 . OCLC 889953315 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Piantadosi CA (2003). The biology of human survival : life and death in extreme environments . Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5 . OCLC 70215878 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Toups, M.A.; Kitchen, A.; Light, J.E.; Reed, D.L. (2011). "Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa" . Molecular Biology and Evolution . 28 (1): 29–32. doi : 10.1093/molbev/msq234 . PMC 3002236 . PMID 20823373 . ^ O'Neil D. "Human Biological Adaptability; Overview" . Palomar College. Archived from the original on 6 March 2013 . Retrieved 6 January 2013 . ^ "Population distribution and density" . BBC. Archived from the original on 23 June 2017 . Retrieved 26 June 2017 . ^ Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management . 30 (4): 492–507. doi : 10.1007/s00267-002-2737-0 . hdl : 10072/6758 . PMID 12481916 . S2CID 25834286 . ^ Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica" . Vanderbilt Journal of Transnational Law . 23 : 819. Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ "Mission to Mars: Mars Science Laboratory Curiosity Rover" . Jet Propulsion Laboratory. Archived from the original on 18 August 2015 . Retrieved 26 August 2015 . ^ "Touchdown! Rosetta's Philae probe lands on comet" . European Space Agency. 12 November 2014. Archived from the original on 22 August 2015 . Retrieved 26 August 2015 . ^ "NEAR-Shoemaker" . NASA . Archived from the original on 26 August 2015 . Retrieved 26 August 2015 . ^ Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station" . JSC Features . Johnson Space Center . Archived from the original on 16 February 2012 . Retrieved 13 February 2012 . ^ Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth" . Proceedings of the National Academy of Sciences of the United States of America . 115 (25): 6506–6511. Bibcode : 2018PNAS..115.6506B . doi : 10.1073/pnas.1711842115 . PMC 6016768 . PMID 29784790 . ^ Tellier LN (2009). Urban world history: an economic and geographical perspective . Presses de l'Université du Québec. p. 26. ISBN 978-2-7605-1588-8 . Retrieved 30 July 2022 . ^ Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, CA: Dickenson Pub. Co. ISBN 978-0-8221-0166-6 . ^ Harl KW (1998). "Population estimates of the Roman Empire" . Tulane.edu. Archived from the original on 7 May 2016 . Retrieved 8 December 2012 . ^ Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis" . International Journal of Hygiene and Environmental Health . 207 (2): 165–178. doi : 10.1078/1438-4639-00259 . PMC 7128933 . PMID 15031959 . ^ "World's population reaches six billion" . BBC News . 5 August 1999. Archived from the original on 15 April 2008 . Retrieved 5 February 2008 . ^ United Nations. "World population to reach 8 billion on 15 November 2022" . United Nations . Archived from the original on 20 January 2023 . Retrieved 27 October 2022 . ^ "Eight billion people, SARS-CoV-2 ancestor and illegal fishing" . Nature . 611 (641): 641. 23 November 2022. Bibcode : 2022Natur.611..641. . doi : 10.1038/d41586-022-03792-4 . S2CID 253764233 . Archived from the original on 26 January 2023 . Retrieved 26 January 2023 . ^ "World Population to Hit Milestone With Birth of 7 Billionth Person" . PBS NewsHour . 27 October 2011. Archived from the original on 24 September 2017 . Retrieved 11 February 2018 . ^ "68% of the world population projected to live in urban areas by 2050, says UN" . United Nations Department of Economic and Social Affairs (DESA) . 16 May 2018. Archived from the original on 10 March 2021 . Retrieved 18 April 2021 . ^ Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF) . U.S. Department of Justice , Bureau of Justice Statistics. Archived (PDF) from the original on 24 February 2013 . Retrieved 1 October 2006 . ^ Roopnarine PD (March 2014). "Humans are apex predators" . Proceedings of the National Academy of Sciences of the United States of America . 111 (9): E796. Bibcode : 2014PNAS..111E.796R . doi : 10.1073/pnas.1323645111 . PMC 3948303 . PMID 24497513 . ^ Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature" . Science . AAAS . Archived from the original on 26 October 2021 . Retrieved 9 May 2021 . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use – principally agriculture – that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.) ^ Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions" . Proceedings of the National Academy of Sciences of the United States of America . 103 (29): 10941–10946. Bibcode : 2006PNAS..10310941P . doi : 10.1073/pnas.0604181103 . PMC 1544153 . PMID 16829570 . ^ Collins D (1976). The Human Revolution: From Ape to Artist . Phaidon. p. 208 . ISBN 978-0-7148-1676-0 . ^ Weisberger, Mindy (March 23, 2024). "Why don't humans have tails? Scientists find answers in an unlikely place" . CNN . Archived from the original on March 24, 2024 . Retrieved March 24, 2024 . ^ Marks JM (2001). Human Biodiversity: Genes, Race, and History . Transaction Publishers. p. 16. ISBN 978-0-202-36656-2 . ^ Gea, J (2008). "The Evolution of the Human Species: A Long Journey for the Respiratory System". Archivos de Bronconeumología ((English Edition)) . 44 (5): 263–270. doi : 10.1016/S1579-2129(08)60042-7 . ^ O'Neil D. "Humans" . Primates . Palomar College. Archived from the original on 11 January 2013 . Retrieved 6 January 2013 . ^ "How to be Human: The reason we are so scarily hairy" . New Scientist . 2017. Archived from the original on 25 February 2021 . Retrieved 29 April 2020 . ^ Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . ^ Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White" . Evolution: Library . PBS. Archived from the original on 16 February 2013 . Retrieved 6 January 2013 . ^ Roser M, Appel C, Ritchie H (8 October 2013). "Human Height" . Our World in Data . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ "Senior Citizens Do Shrink – Just One of the Body Changes of Aging" . News . Senior Journal. Archived from the original on 19 February 2013 . Retrieved 6 January 2013 . ^ Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology . 136 (1): 71–84. doi : 10.1016/S1095-6433(02)00294-5 . PMID 14527631 . ^ "Human weight" . Articleworld.org. Archived from the original on 8 December 2011 . Retrieved 10 December 2011 . ^ Schlessingerman A (2003). "Mass Of An Adult" . The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018 . Retrieved 31 December 2017 . ^ Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology) . Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1 . Retrieved 5 April 2009 . ^ Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care" . British Journal of Anaesthesia . 85 (1): 91–108. doi : 10.1093/bja/85.1.91 . PMID 10927998 . ^ Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology . 93 (1): 1–16. doi : 10.1086/696721 . ISSN 0033-5770 . S2CID 90757192 . ^ Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance" . The New York Times . Archived from the original on 5 November 2015. ^ John B. "What is the role of sweating glands in balancing body temperature when running a marathon?" . Livestrong.com. Archived from the original on 31 January 2013 . Retrieved 6 January 2013 . ^ Shave, R. E.; Lieberman, D. E.; Drane, A. L.; et al. (2019). "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart" . PNAS . 116 (40): 19905–19910. Bibcode : 2019PNAS..11619905S . doi : 10.1073/pnas.1906902116 . PMC 6778238 . PMID 31527253 . ^ Ríos, L; Sleeper, M. M.; Danforth, M. D.; et al. (2023). "The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution" . Scientific Reports . 13 (6841): 6841. Bibcode : 2023NatSR..13.6841R . doi : 10.1038/s41598-023-33675-1 . hdl : 10261/309357 . PMC 10133235 . PMID 37100851 . ^ Therman E (1980). Human Chromosomes: Structure, Behavior, Effects . Springer US . pp. 112–124. doi : 10.1007/978-1-4684-0107-3 . ISBN 978-1-4684-0109-7 . S2CID 36686283 . ^ Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex" . Journal of Medical Genetics . 3 (2): 117–123. doi : 10.1136/jmg.3.2.117 . PMC 1012913 . PMID 6007033 . ^ Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics . 61 (3): 216–228. doi : 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S . PMID 8741866 . ^ Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics . 53 (1): 27–34. doi : 10.1038/s41588-020-00755-1 . PMID 33414551 . S2CID 230986741 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . Between any two humans, the amount of genetic variation – biochemical individuality – is about 0.1%. ^ Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human" . PLOS Biology . 5 (10): e254. doi : 10.1371/journal.pbio.0050254 . PMC 1964779 . PMID 17803354 . ^ Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research" . American Journal of Human Genetics . 77 (4): 519–532. doi : 10.1086/491747 . PMC 1275602 . PMID 16175499 . ^ "Chimps show much greater genetic diversity than humans" . Media . University of Oxford. Archived from the original on 18 December 2013 . Retrieved 13 December 2013 . ^ Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography" . Proceedings of the National Academy of Sciences of the United States of America . 95 (4): 1961–1967. Bibcode : 1998PNAS...95.1961H . doi : 10.1073/pnas.95.4.1961 . PMC 19224 . PMID 9465125 . ^ Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans" . Proceedings of the National Academy of Sciences of the United States of America . 94 (7): 3100–3103. Bibcode : 1997PNAS...94.3100J . doi : 10.1073/pnas.94.7.3100 . PMC 20328 . PMID 9096352 . ^ Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story" . The New York Times . Archived from the original on 14 January 2012 . Retrieved 13 February 2012 . ^ Pennisi E (February 2001). "The human genome". Science . 291 (5507): 1177–1180. doi : 10.1126/science.291.5507.1177 . PMID 11233420 . S2CID 38355565 . ^ Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature . 590 (7845): 220–221. Bibcode : 2021Natur.590..220R . doi : 10.1038/d41586-021-00237-2 . PMID 33568827 . S2CID 231882262 . ^ Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations" . Nature . 467 (7311): 52–58. Bibcode : 2010Natur.467...52T . doi : 10.1038/nature09298 . PMC 3173859 . PMID 20811451 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private , common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture. ^ Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes" . Genome Biology . 11 (5): 206. doi : 10.1186/gb-2010-11-5-206 . PMC 2898077 . PMID 20441615 . ^ Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature . 325 (6099): 31–36. Bibcode : 1987Natur.325...31C . doi : 10.1038/325031a0 . PMID 3025745 . S2CID 4285418 . ^ Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock" . American Journal of Human Genetics . 84 (6): 740–759. doi : 10.1016/j.ajhg.2009.05.001 . PMC 2694979 . PMID 19500773 . ^ "University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history" . 20 August 2017. Archived from the original on 20 August 2017. ^ Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females" . Science . 341 (6145): 562–565. Bibcode : 2013Sci...341..562P . doi : 10.1126/science.1237619 . PMC 4032117 . PMID 23908239 . ^ Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set . John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1 . ^ Jukic AM, Baird DD, Weinberg CR , McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation" . Human Reproduction . 28 (10): 2848–2855. doi : 10.1093/humrep/det297 . PMC 3777570 . PMID 23922246 . ^ Klossner NJ (2005). Introductory Maternity Nursing . Lippincott Williams & Wilkins. p. 103. ISBN 978-0-7817-6237-3 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . The fetal stage is from the beginning of the 9th week after fertilization and continues until birth ^ World Health Organization (November 2014). "Preterm birth Fact sheet N°363" . who.int . Archived from the original on 7 March 2015 . Retrieved 6 March 2015 . ^ Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application" . American Journal of Obstetrics and Gynecology . 218 (2S): S619–S629. doi : 10.1016/j.ajog.2017.12.010 . PMID 29422204 . S2CID 46810955 . ^ "What is the average baby length? Growth chart by month" . www.medicalnewstoday.com . 18 March 2019. Archived from the original on 27 January 2021 . Retrieved 18 April 2021 . ^ Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal . 5 (2): 113–122. PMID 15024783 . ^ Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology . 35 (S15): 89–124. doi : 10.1002/ajpa.1330350605 . ISSN 1096-8644 . ^ Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma" . American Journal of Obstetrics and Gynecology . 222 (1): 3–16. doi : 10.1016/j.ajog.2019.06.043 . PMC 9069416 . PMID 31251927 . S2CID 195761874 . ^ Barras C (22 December 2016). "The real reasons why childbirth is so painful and dangerous". BBC. ^ Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?" . Newsweek . Archived from the original on 28 June 2007. A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa , compared to 1 in 2,800 in developed countries . ^ Rush D (July 2000). "Nutrition and maternal mortality in the developing world" . The American Journal of Clinical Nutrition . 72 (1 Suppl): 212S–240S. doi : 10.1093/ajcn/72.1.212S . PMID 10871588 . ^ Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour . Oxford University Press. p. 7. ISBN 978-0-19-958696-7 . Retrieved 30 July 2022 . ^ Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning . p. 296. ISBN 978-0-495-60037-4 . Archived from the original on 3 October 2023 . Retrieved 30 July 2022 . ^ Schuiling KD, Likis FE (2016). Women's Gynecologic Health . Jones & Bartlett Learning . p. 22. ISBN 978-1-284-12501-6 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13. ^ Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy . SAGE Publications . pp. 18–19. ISBN 978-1-4833-6475-9 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average). ^ Mintz S (1993). "Life stages". Encyclopedia of American Social History . 3 : 7–33. ^ Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?" . Indian Journal of Endocrinology and Metabolism . 18 (Suppl 1): S53-62. doi : 10.4103/2230-8210.145075 . PMC 4266869 . PMID 25538878 . ^ Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?" . Biology of Reproduction . 79 (3): 398–406. doi : 10.1095/biolreprod.108.068536 . PMC 2553520 . PMID 18495681 . ^ Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality . New York: Basic Books. pp. 167–170. ISBN 978-0-465-03127-6 . ^ Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology . 10 (2): 43–57. doi : 10.1002/evan.1013 . S2CID 1665503 . ^ Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth" . USC Trojan Family Magazine . Archived from the original on 13 December 2010 . Retrieved 7 December 2010 . ^ Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex" . Society of Actuaries. Archived from the original on 1 July 2013. ^ "Life expectancy at birth, female (years)" . World Bank . 2018. Archived from the original on 24 January 2021 . Retrieved 13 October 2020 . ^ "Life expectancy at birth, male (years)" . World Bank . 2018. Archived from the original on 24 February 2021 . Retrieved 13 October 2020 . ^ Conceição P, et al. (2019). Human Development Report (PDF) . United Nations Development Programme. ISBN 978-92-1-126439-5 . Archived (PDF) from the original on 20 March 2021 . Retrieved 30 July 2022 . ^ "Human Development Report 2019" (PDF) . United Nations Development Programme . Archived from the original (PDF) on 22 April 2022 . Retrieved 30 July 2022 . ^ "The World Factbook" . U.S. Central Intelligence Agency. Archived from the original on 12 September 2009 . Retrieved 2 April 2005 . ^ "Chapter 1: Setting the Scene" (PDF) . UNFPA. 2012. Archived from the original (PDF) on 12 June 2013 . Retrieved 11 January 2013 . ^ Haenel H (1989). "Phylogenesis and nutrition". Die Nahrung . 33 (9): 867–887. PMID 2697806 . ^ Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable . pp. 264–265. Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods. ^ American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association . 103 (6): 748–765. doi : 10.1053/jada.2003.50142 . PMID 12778049 . ^ Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet" . American Journal of Physical Anthropology . 162 (S63): 84–109. doi : 10.1002/ajpa.23148 . PMID 28105723 . ^ Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century" . The American Journal of Clinical Nutrition . 81 (2): 341–354. doi : 10.1093/ajcn.81.2.341 . PMID 15699220 . ^ Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context" . The Proceedings of the Nutrition Society . 61 (4): 517–526. doi : 10.1079/PNS2002180 . PMID 12691181 . ^ John Carey (2023). "Unearthing the origins of agriculture" . Proceedings of the National Academy of Sciences . 120 (15): e2304407120. Bibcode : 2023PNAS..12004407C . doi : 10.1073/pnas.2304407120 . PMC 10104519 . PMID 37018195 . ^ Ayelet Shavit; Gonen Sharon (2023). "Can models of evolutionary transition clarify the debates over the Neolithic Revolution?" . Philosophical Transactions of the Royal Society B . 378 (1872). doi : 10.1098/rstb.2021.0413 . PMC 9869441 . PMID 36688395 . } ^ Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences" . The American Journal of Clinical Nutrition . 90 (3): 707S–711S. doi : 10.3945/ajcn.2009.27462B . PMID 19656837 . ^ Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology . 69 (5): 605–628. PMID 9299882 . ^ Gibbons A. "The Evolution of Diet" . National Geographic . Archived from the original on 18 August 2014 . Retrieved 18 April 2021 . ^ Ritchie H, Roser M (20 August 2017). "Diet Compositions" . Our World in Data . Archived from the original on 25 August 2021 . Retrieved 30 July 2022 . ^ Lieberson AD (2004). "How Long Can a Person Survive without Food?" . Scientific American . Archived from the original on 14 February 2019 . Retrieved 18 April 2021 . ^ Spector D (9 March 2018). "Here's how many days a person can survive without water" . Business Insider Australia . Archived from the original on 26 June 2014 . Retrieved 18 April 2021 . ^ Holmes J. "Losing 25,000 to Hunger Every Day" . United Nations . Archived from the original on 27 May 2020 . Retrieved 18 April 2021 . ^ Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic" . NPR . Archived from the original on 28 June 2021 . Retrieved 18 April 2021 . ^ Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet . 349 (9063): 1436–1442. doi : 10.1016/S0140-6736(96)07495-8 . PMID 9164317 . S2CID 2569153 . ^ Haslam DW, James WP (October 2005). "Obesity". Lancet . 366 (9492): 1197–1209. doi : 10.1016/S0140-6736(05)67483-1 . PMID 16198769 . S2CID 208791491 . ^ Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine . 30 (3): 415–444, vii. doi : 10.1016/j.ccm.2009.05.001 . PMID 19700042 . ^ de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology . 2 (1): 45–55. doi : 10.1016/j.ehb.2003.11.001 . PMID 15463992 . ^ O'Neil D. "Adapting to Climate Extremes" . Human Biological Adaptability . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status" . PLOS Genetics . 13 (9): e1006977. doi : 10.1371/journal.pgen.1006977 . PMC 5600404 . PMID 28873402 . ^ Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics . 35 (4): 311–313. doi : 10.1038/ng1263 . PMID 14634648 . S2CID 20415396 . ^ Hedrick PW (October 2011). "Population genetics of malaria resistance in humans" . Heredity . 107 (4): 283–304. doi : 10.1038/hdy.2011.16 . PMC 3182497 . PMID 21427751 . ^ Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria" . British Journal of Haematology . 141 (3): 276–286. doi : 10.1111/j.1365-2141.2008.07085.x . PMID 18410566 . S2CID 28191911 . ^ Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea" . Frontiers in Ecology and Evolution . 5 . doi : 10.3389/fevo.2017.00025 . hdl : 11858/00-001M-0000-002C-DD87-4 . ISSN 2296-701X . S2CID 34882477 . ^ Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads" . Cell . 173 (3): 569–580.e15. doi : 10.1016/j.cell.2018.03.054 . PMID 29677510 . ^ Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology . 45 (1): 105–08. doi : 10.1086/381006 . S2CID 224795768 . ^ Roberts D (2011). Fatal Invention . London & New York: The New Press. ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation" . Proceedings of the National Academy of Sciences of the United States of America . 107 (Supplement_2): 8962–8968. Bibcode : 2010PNAS..107.8962J . doi : 10.1073/pnas.0914628107 . PMC 3024016 . PMID 20445093 . ^ Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF) . Journal of Human Evolution . 39 (1): 57–106. doi : 10.1006/jhev.2000.0403 . PMID 10896812 . Archived from the original (PDF) on 14 January 2012. ^ Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R" . American Journal of Human Genetics . 66 (4): 1351–1361. doi : 10.1086/302863 . PMC 1288200 . PMID 10733465 . ^ Robin A (1991). Biological Perspectives on Human Pigmentation . Cambridge: Cambridge University Press. ^ "The Science Behind the Human Genome Project" . Human Genome Project . US Department of Energy. Archived from the original on 2 January 2013 . Retrieved 6 January 2013 . Almost all (99.9%) nucleotide bases are exactly the same in all people. ^ O'Neil D. "Ethnicity and Race: Overview" . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation" . Nature Genetics . 36 (11 Suppl): S17-20. doi : 10.1038/ng1455 . PMID 15507998 . ^ O'Neil D. "Models of Classification" . Modern Human Variation . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Palmié S (May 2007). "Genomics, divination, 'racecraft' ". American Ethnologist . 34 (2): 205–222. doi : 10.1525/ae.2007.34.2.205 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations. ^ Goodman A. "Interview with Alan Goodman" . Race Power of and Illusion . PBS. Archived from the original on 29 October 2012 . Retrieved 6 January 2013 . ^ Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF) . New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012 . Retrieved 5 September 2013 . ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo ^ O'Neil D. "Overview" . Modern Human Variation . Palomar College. Archived from the original on 5 November 2012 . Retrieved 6 January 2013 . ^ Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" . American Journal of Human Genetics . 66 (3): 979–988. doi : 10.1086/302825 . PMC 1288178 . PMID 10712212 . ^ "New Research Proves Single Origin Of Humans In Africa" . Science Daily . 19 July 2007. Archived from the original on 4 November 2011 . Retrieved 5 September 2011 . ^ Manica A, Amos W, Balloux F , Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation" . Nature . 448 (7151): 346–348. Bibcode : 2007Natur.448..346M . doi : 10.1038/nature05951 . PMC 1978547 . PMID 17637668 . ^ Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals" . Cell . 180 (4): 677–687.e16. doi : 10.1016/j.cell.2020.01.012 . PMID 32004458 . S2CID 210955842 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations. ^ Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations" . Science Advances . 6 (7): eaax5097. Bibcode : 2020SciA....6.5097D . doi : 10.1126/sciadv.aax5097 . PMC 7015685 . PMID 32095519 . Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. ^ Pierce BA (2012). Genetics: A Conceptual Approach . Macmillan. p. 75. ISBN 978-1-4292-3252-4 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology . Cambridge University Press. p. 74. ISBN 978-0-521-87948-4 . Retrieved 30 July 2022 . ^ Fusco G, Minelli A (10 October 2019). The Biology of Reproduction . Cambridge University Press. p. 304. ISBN 978-1-108-49985-9 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution . 47 (4): 253–266. doi : 10.1016/j.jhevol.2004.07.004 . PMID 15454336 . ^ Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960–2002" (PDF) . Advance Data (347): 1–17. PMID 15544194 . Archived from the original (PDF) on 23 February 2011. ^ Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology . 66 (3): 254–262. doi : 10.1007/BF00235103 . hdl : 11375/22586 . PMID 8477683 . S2CID 206772211 . ^ Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity . Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi : 10.1007/978-3-319-70178-3_2 . ISBN 978-3-319-70177-6 . PMID 29224088 . ^ Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know" . International Journal of Women's Dermatology . 4 (3): 122–130. doi : 10.1016/j.ijwd.2018.03.002 . PMC 6116811 . PMID 30175213 . ^ Easter C. "Sex Linked" . National Human Genome Research Institute . Archived from the original on 14 April 2022 . Retrieved 18 April 2021 . ^ Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior . 27 (4): 283–296. doi : 10.1016/j.evolhumbehav.2005.11.003 . S2CID 32562654 . ^ "Gender, women, and health" . Reports from WHO 2002–2005 . Archived from the original on 25 June 2013. ^ Sax, Leonard (1 August 2002). "How common is lntersex? A response to Anne Fausto-Sterling" . The Journal of Sex Research . 39 (3): 174–178. doi : 10.1080/00224490209552139 . ISSN 0022-4499 . PMID 12476264 . S2CID 33795209 . ^ "3-D Brain Anatomy" . The Secret Life of the Brain . Public Broadcasting Service. Archived from the original on 5 September 2017 . Retrieved 3 April 2005 . ^ Stern P (22 June 2018). "The human prefrontal cortex is special" . Science . 360 (6395): 1311–1312. Bibcode : 2018Sci...360S1311S . doi : 10.1126/science.360.6395.1311-g . ISSN 0036-8075 . S2CID 149581944 . ^ Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?" . Journal of Intelligence . 2 (3): 119–121. doi : 10.3390/jintelligence2030119 . ISSN 2079-3200 . ^ "Humans not smarter than animals, just different, experts say" . phys.org . Archived from the original on 30 January 2021 . Retrieved 24 October 2020 . ^ Robson D. "We've got human intelligence all wrong" . www.bbc.com . Archived from the original on 31 January 2021 . Retrieved 24 October 2020 . ^ Owen J (26 February 2015). "Many Animals – Including Your Dog – May Have Horrible Short-Term Memories" . National Geographic News . Archived from the original on 19 April 2021 . Retrieved 6 September 2020 . ^ Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research" . American Journal of Physical Anthropology . 116 (S33): 3–24. doi : 10.1002/ajpa.20001 . PMC 2238342 . PMID 11786989 . ^ Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?" . ABC News (American) . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self" . New Scientist . Archived from the original on 18 February 2021 . Retrieved 22 April 2020 . ^ Beck J (2019). "Can We Really Know What Animals Are Thinking?" . Snopes . Archived from the original on 31 October 2021 . Retrieved 22 April 2020 . ^ Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies" . Sleep Medicine Reviews . 14 (4): 239–247. doi : 10.1016/j.smrv.2009.08.001 . PMC 2888649 . PMID 19896872 . ^ Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep" " . Science.howstuffworks.com. Archived from the original on 15 May 2012 . Retrieved 11 August 2012 . ^ Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience . 10 (11): 803–813. doi : 10.1038/nrn2716 . PMID 19794431 . S2CID 205505278 . ^ Empson J (2002). Sleep and dreaming (3rd ed.). New York: Palgrave/St. Martin's Press. ^ Lite J (29 July 2010). "How Can You Control Your Dreams?" . Scientific America . Archived from the original on 2 February 2015. ^ Domhoff W (2002). The scientific study of dreams . APA Press. ^ "Consciousness" . Merriam-Webster . Archived from the original on 7 September 2019 . Retrieved 4 June 2012 . ^ van Gulick R (2004). "Consciousness" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019 . Retrieved 30 July 2022 . ^ Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness . Wiley. ISBN 978-0-470-75145-9 . ^ Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy . Oxford University Press. ISBN 978-0-19-926479-7 . ^ Block N (June 1995). "On a confusion about a function of consciousness" . Behavioral and Brain Sciences . 18 (2): 227–247. doi : 10.1017/S0140525X00038474 . S2CID 246244859 . ^ Jaynes J (2000) [1976]. The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF) . Houghton Mifflin. ISBN 0-618-05707-2 . Archived from the original (PDF) on 7 August 2019 . Retrieved 25 October 2020 . ^ Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition . 12 (4): 717–731. doi : 10.1016/s1053-8100(03)00081-3 . PMID 14656513 . S2CID 10241157 . ^ Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness" . Stanford Encyclopedia of Philosophy . Archived from the original on 13 April 2021 . Retrieved 31 August 2014 . ^ Antony MV (2001). "Is consciousness ambiguous?". Journal of Consciousness Studies . 8 : 19–44. ^ "Cognition" . Lexico . Oxford University Press and Dictionary.com . Archived from the original on 8 July 2016 . Retrieved 6 May 2020 . ^ Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality . The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi : 10.1007/978-3-030-03633-1_14 . ISBN 978-3-030-03633-1 . S2CID 189379814 . ^ "American Psychological Association (2013). Glossary of psychological terms" . Apa.org. Archived from the original on 8 July 2014 . Retrieved 13 August 2014 . ^ "Developmental Psychology Studies Human Development Across the Lifespan" . www.apa.org . Archived from the original on 9 July 2014 . Retrieved 28 August 2017 . ^ Burman E (2017). Deconstructing Developmental Psychology . New York: Routledge. ISBN 978-1-138-84695-1 . ^ Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology : 307–314. doi : 10.1016/B0-12-657410-3/00510-9 . ISBN 978-0-12-657410-4 . ^ McLeod S (20 March 2020). "Maslow's Hierarchy of Needs" . Simplypsychology.org . Simply Scholar Limited. Archived from the original on 8 November 2018 . Retrieved 4 April 2020 . Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up. ^ Heckhausen J, Heckhausen H (28 March 2018). "Motivation and Action: Introduction and Overview". Motivation and Action . Introduction and Overview: Springer, Cham. p. 1. doi : 10.1007/978-3-319-65094-4_1 . ISBN 978-3-319-65093-7 . ^ Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews . 26 (2–3): 83–86. doi : 10.1016/s0165-0173(97)00064-7 . PMID 9651488 . S2CID 8504450 . ^ Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions . New York: Oxford University Press. pp. 291–293. ISBN 978-0-19-508944-8 . Emotional processing, but not emotions, can occur unconsciously. ^ Cabanac M (2002). "What is emotion?". Behavioural Processes . 60 (2): 69–83. doi : 10.1016/S0376-6357(02)00078-5 . PMID 12426062 . S2CID 24365776 . Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure) ^ Scirst DL (2011). Psychology Second Edition . New York: Worth Publishers. p. 310 . ISBN 978-1-4292-3719-2 . ^ Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality . 67 (2): 331–371. doi : 10.1111/1467-6494.00058 . PMID 10202807 . ^ Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory" . Frontiers in Psychology . 8 : 1454. doi : 10.3389/fpsyg.2017.01454 . PMC 5573739 . PMID 28883804 . ^ Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology . Oxford University Press. Archived from the original on 29 January 2021 . Retrieved 30 July 2022 . ^ Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals" . Industrial Psychiatry Journal . 24 (1): 54–58. doi : 10.4103/0972-6748.160934 . PMC 4525433 . PMID 26257484 . ^ Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions" . The American Psychologist . 56 (3): 218–226. doi : 10.1037/0003-066X.56.3.218 . PMC 3122271 . PMID 11315248 . ^ Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica . 90 (3): 387–411. doi : 10.11612/resphil.2013.90.3.5 . ^ Haybron DM (13 April 2014). "Happiness and Its Discontents" . The Opinion Pages . The New York Times. Archived from the original on 12 October 2018 . Retrieved 30 July 2022 . I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life. ^ Graham MC (2014). Facts of Life: ten issues of contentment . Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5 . ^ "Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy" . ScienceDaily . American Psychological Association . 14 August 2017. Archived from the original on 11 November 2020 . Retrieved 25 October 2020 . ^ Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality . Jones & Bartlett Publishers . pp. 4–10. ISBN 978-1-284-08154-1 . Retrieved 21 June 2017 . Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings. ^ Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives . Taylor & Francis . pp. 32–42. ISBN 978-0-7890-2671-2 . ^ Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology . 3 (4): 85–89. doi : 10.1097/01.XHA.0000432482.01760.b0 . S2CID 147235090 . ^ "Sexual orientation, homosexuality and bisexuality" . American Psychological Association . Archived from the original on 8 August 2013 . Retrieved 10 August 2013 . ^ Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science" . Psychological Science in the Public Interest . 17 (2): 45–101. doi : 10.1177/1529100616637616 . PMID 27113562 . ^ LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation . Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6 . Retrieved 30 July 2022 . ^ Balthazart J (2012). The Biology of Homosexuality . Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0 . Retrieved 30 July 2022 . ^ Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York: Basic Books. ISBN 978-0-465-00802-5 . ^ Fromm E (2000). The art of loving . New York: Harper Perennial. ISBN 978-0-06-095828-2 . ^ "Love, Actually: The science behind lust, attraction, and companionship" . Science in the News . 14 February 2017. Archived from the original on 28 October 2020 . Retrieved 25 October 2020 . ^ "What are the top 200 most spoken languages?" . Ethnologue: Languages of the World . 2020. Archived from the original on 12 January 2013 . Retrieved 30 July 2022 . ^ World . The World Factbook (Report). Central Intelligence Agency . Archived from the original on 26 January 2021 . Retrieved 15 November 2021 . ^ "The Changing Global Religious Landscape" . Pew Research Center. 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 30 July 2022 . ^ Ord T (2020). The Precipice: Existential Risk and the Future of Humanity . New York: Hachette Books. ISBN 978-0-316-48489-3 . Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence... ^ Goldman JG (2012). "Pay attention… time for lessons at animal school" . bbc.com . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding" . Science Advances . 4 (11): eaar8334. Bibcode : 2018SciA....4.8334W . doi : 10.1126/sciadv.aar8334 . PMC 6248967 . PMID 30474053 . ^ Johnson-Frey SH (July 2003). "What's so special about human tool use?" . Neuron . 39 (2): 201–204. doi : 10.1016/S0896-6273(03)00424-0 . PMID 12873378 . S2CID 18437970 . ^ Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology . 19 (1): 27–33. doi : 10.1016/j.conb.2009.02.003 . PMID 19328675 . S2CID 18277620 . In short, the evidence to date that animals have an understanding of folk physics is at best mixed. ^ Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To" . National Geographic News . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education" . Procedia - Social and Behavioral Sciences . The Proceedings of 6th World Conference on educational Sciences. 191 : 2565–2567. doi : 10.1016/j.sbspro.2015.04.690 . ISSN 1877-0428 . ^ McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species" . The Guardian . Archived from the original on 5 February 2021 . Retrieved 22 April 2020 . ^ Nicholls H (29 June 2015). "Babblers speak to the origin of language" . The Guardian . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Dasgupta S (2015). "Can any animals talk and use language like humans?" . bbc.com . Archived from the original on 2 May 2020 . Retrieved 22 April 2020 . Most animals are not vocal learners. ^ Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?" . Royal Society. Archived from the original on 18 January 2021 . Retrieved 24 October 2020 . ^ Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?" . BMC Biology . 15 (1): 64. doi : 10.1186/s12915-017-0405-3 . PMC 5525259 . PMID 28738867 . ^ Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist . 208 (2789): ii–iii. Bibcode : 2010NewSc.208D...2F . doi : 10.1016/S0262-4079(10)62961-2 . ISSN 0262-4079 . ^ Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments . London: Palgrave Macmillan UK. pp. 229–255. doi : 10.1057/978-1-137-58746-6_7 . ISBN 978-1-137-58746-6 . ^ "Culture | United Nations For Indigenous Peoples" . www.un.org . 5 June 2015. Archived from the original on 26 November 2020 . Retrieved 24 October 2020 . ^ Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World . New York: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1 . ^ Mavrody S (2013). Visual Art Forms: Traditional to Digital . Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9 . Retrieved 30 July 2022 . ^ "Types of Literary Arts and Their Understanding – bookfestivalscotland.com" . Bookfestival Scotland . 2020. Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ "Bachelor of Performing Arts" (PDF) . University of Otago . Archived (PDF) from the original on 14 December 2021 . Retrieved 30 July 2022 . ^ Brown S (24 October 2018). "Toward a Unification of the Arts" . Frontiers in Psychology . 9 : 1938. doi : 10.3389/fpsyg.2018.01938 . ISSN 1664-1078 . PMC 6207603 . PMID 30405470 . ^ "Culinary arts – How cooking can be an art" . Northern Contemporary Art . 21 October 2019. Archived from the original on 11 May 2021 . Retrieved 5 May 2021 . ^ Smuts A (1 January 2005). "Are Video Games Art?" . Contemporary Aesthetics (Journal Archive) . 3 (1). Archived from the original on 29 May 2022 . Retrieved 30 July 2022 . ^ Cameron IA, Pimlott N (September 2015). "Art of medicine" . Canadian Family Physician . 61 (9): 739–740. PMC 4569099 . PMID 26371092 . ^ Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy . 25 (4): 458–470. doi : 10.1080/10286632.2017.1311328 . ISSN 1028-6632 . S2CID 151443044 . ^ Morriss-Kay GM (February 2010). "The evolution of human artistic creativity" . Journal of Anatomy . 216 (2): 158–176. doi : 10.1111/j.1469-7580.2009.01160.x . PMC 2815939 . PMID 19900185 . ^ Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature . 518 (7538): 228–231. Bibcode : 2015Natur.518..228J . doi : 10.1038/nature13962 . PMID 25470048 . S2CID 4461751 . ^ St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave" . The New York Times . Archived from the original on 14 April 2020 . Retrieved 20 September 2018 . ^ Radford T (16 April 2004). "World's oldest jewellery found in cave" . The Guardian . ISSN 0261-3077 . Archived from the original on 12 February 2021 . Retrieved 23 September 2020 . ^ Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches . Amsterdam: Valiz. pp. 241–263. ^ Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia . 92 (92): 147–177. doi : 10.4436/JASS.92008 (inactive 2024-03-20). PMID 25020016 . {{ cite journal }} : CS1 maint: DOI inactive as of March 2024 ( link ) ^ Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness" (PDF) . NeuroImage . 103 : 55–64. doi : 10.1016/j.neuroimage.2014.09.009 . PMID 25224999 . S2CID 4727529 . ^ Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences . 1337 (1): 140–146. Bibcode : 2015NYASA1337..140K . doi : 10.1111/nyas.12632 . PMID 25773628 . S2CID 206224849 . ^ Chow D (22 March 2010). "Why Do Humans Dance?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 21 September 2020 . ^ Krakauer J (26 September 2008). "Why do we like to dance – And move to the beat?" . Scientific American . Archived from the original on 28 February 2021 . Retrieved 21 September 2020 . ^ Prior KS (21 June 2013). "How Reading Makes Us More Human" . The Atlantic . Archived from the original on 29 January 2021 . Retrieved 23 September 2020 . ^ Puchner M. "How stories have shaped the world" . www.bbc.com . Archived from the original on 5 January 2021 . Retrieved 23 September 2020 . ^ Dalley, Stephanie , ed. (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5 . ^ Hernadi P (2001). "Literature and Evolution" . SubStance . 30 (1/2): 55–71. doi : 10.2307/3685504 . ISSN 0049-2426 . JSTOR 3685504 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run" . The Guardian (U.S. ed.). New York. Archived from the original on 18 June 2022 . Retrieved 30 July 2022 . ^ Clark JD; de Heinzelin J ; Schick KD ; Hart WK; White TD ; WoldeGabriel G; Walter RC; Suwa G ; Asfaw B ; Vrba E ; H.-Selassie Y (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science . 264 (5167): 1907–1910. Bibcode : 1994Sci...264.1907C . doi : 10.1126/science.8009220 . PMID 8009220 . ^ Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use" . livescience.com . Archived from the original on 4 October 2020 . Retrieved 9 October 2020 . ^ Orban GA, Caruana F (2014). "The neural basis of human tool use" . Frontiers in Psychology . 5 : 310. doi : 10.3389/fpsyg.2014.00310 . PMC 3988392 . PMID 24782809 . ^ Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa" . Proceedings of the National Academy of Sciences of the United States of America . 109 (20): E1215-20. doi : 10.1073/pnas.1117620109 . PMC 3356665 . PMID 22474385 . ^ Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1696): 20150164. doi : 10.1098/rstb.2015.0164 . PMC 4874402 . PMID 27216521 . ^ Damiano J (2018). "Neolithic Era Tools: Inventing a New Age" . MagellanTV . Archived from the original on 5 January 2021 . Retrieved 9 October 2020 . ^ Deng Y, Wang P (2011). Ancient Chinese inventions . Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6 . OCLC 671710733 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Schifman J (9 July 2018). "The Entire History of Steel" . Popular Mechanics . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Wilkinson, Freddie (9 January 2020). "Industrial Revolution and Technology" . National Geographic Society . Archived from the original on 30 September 2020 . Retrieved 9 October 2020 . ^ Roser, Max ; Ritchie, Hannah (11 May 2013). "Technological Progress" . Our World in Data . Archived from the original on 10 September 2021 . Retrieved 30 July 2022 . ^ Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel" . The Atlantic . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Idinopulos TA (1998). "What Is Religion?" . CrossCurrents . 48 (3): 366–380. ISSN 0011-1953 . JSTOR 24460821 . Archived from the original on 13 October 2020 . Retrieved 30 July 2022 . ^ Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology . 54 (1): 377–402. doi : 10.1146/annurev.psych.54.101601.145024 . PMID 12171998 . ^ King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?" . The Atlantic . Archived from the original on 20 January 2021 . Retrieved 8 October 2020 . ^ Ball P (2015). "Complex societies evolved without belief in all-powerful deity" . Nature News . doi : 10.1038/nature.2015.17040 . S2CID 183474917 . Archived from the original on 16 May 2021 . Retrieved 30 July 2022 . ^ Culotta E (November 2009). "Origins. On the origin of religion". Science . 326 (5954): 784–787. Bibcode : 2009Sci...326..784C . doi : 10.1126/science.326_784 . PMID 19892955 . ^ Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation" . Evolution and Human Behavior . 32 (1): 41–49. doi : 10.1016/j.evolhumbehav.2010.07.008 . ISSN 1090-5138 . Archived from the original on 15 October 2020 . Retrieved 30 July 2022 . ^ Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA – Journal of Death and Dying . 41 (1): 5–22. doi : 10.2190/Q21C-5VED-GYW6-W091 . ISSN 0030-2228 . S2CID 145686249 . ^ McKay R, Whitehouse H (March 2015). "Religion and morality" . Psychological Bulletin . 141 (2): 447–473. doi : 10.1037/a0038455 . PMC 4345965 . PMID 25528346 . ^ Bernhard Nitsche; Marcus Schmücker, eds. (2023). God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality . De Gruyter . doi : 10.1515/9783110698343 . ISBN 978-3-11-069834-3 . ^ Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique" . Journal of Religion and Health (Submitted manuscript). 47 (2): 134–163. doi : 10.1007/s10943-008-9165-2 . PMC 8823950 . PMID 19105008 . S2CID 25349208 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular" . The Guardian . ISSN 0261-3077 . Archived from the original on 1 March 2021 . Retrieved 8 October 2020 . ^ Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe" . Pew Research Center . Archived from the original on 24 November 2019 . Retrieved 8 October 2020 . ^ "The Changing Global Religious Landscape" . Pew Research Center's Religion & Public Life Project . 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 8 October 2020 . ^ Di Christina, Mariette (September 2018). "A Very Human Story: Why Our Species Is Special" . Scientific American . Archived from the original on 24 November 2020 . Retrieved 27 September 2020 . ^ Andersen H , Hepburn B (2020). "Scientific Method" . In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Lo Presti R (2014). "History of science: The first scientist" . Nature . 512 (7514): 250–251. Bibcode : 2014Natur.512..250L . doi : 10.1038/512250a . ISSN 1476-4687 . S2CID 4394696 . ^ Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn . Springer. p. 1. ISBN 978-3-642-18904-3 . OCLC 883392276 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Needham, J ; Wang Ling (1954). Science and civilisation in China . Cambridge University Press. p. 111. ISBN 0-521-05799-X . OCLC 779676 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6 . OCLC 615209781 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017 . Retrieved 3 July 2017 . ^ Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition . Cambridge University Press. pp. 209–210. ISBN 978-1-107-01116-8 . ^ "Branches of Science" (PDF) . University of Chicago . Archived from the original (PDF) on 23 April 2017 . Retrieved 26 June 2017 . ^ "What is Philosophy?" . Department of Philosophy . Florida State University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ "Philosophy" . Definition, Systems, Fields, Schools, & Biographies . Encyclopedia Britannica. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day" . Philosophy and Phenomenological Research . 7 (3): 461. doi : 10.2307/2102800 . JSTOR 2102800 . Archived from the original on 31 March 2022 . Retrieved 30 July 2022 . ^ Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?" . ieet.org . Archived from the original on 4 March 2021 . Retrieved 8 August 2020 . ^ Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?" . European Journal of Information Systems . 27 (3): 263–277. doi : 10.1080/0960085X.2018.1470776 . hdl : 2086/16128 . ISSN 0960-085X . S2CID 64796132 . ^ Schizzerotto A. "Social Stratification" (PDF) . University of Trento . Archived from the original (PDF) on 20 March 2018 . Retrieved 3 July 2017 . ^ Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution . Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9 . OCLC 1082411117 . ^ "Social Role Theory of Sex Differences and Similarities : A Current Appraisal" . The Developmental Social Psychology of Gender . Psychology Press. 2000. pp. 137–188. doi : 10.4324/9781410605245-12 . ISBN 978-1-4106-0524-5 . Archived from the original on 30 April 2021 . Retrieved 10 June 2022 . ^ Blackstone, Amy (2003). "Gender Roles and Society" . In Miller, Julia R.; Lerner, Richard M.; Schiamberg, Lawrence B. (eds.). Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments . Sociology School Faculty Scholarship. Santa barbara, CA: ABC-CLIO. p. 335. Archived from the original on 16 May 2022 . Retrieved 30 July 2022 . ^ Nadal, Kevin L. (2017). The SAGE Encyclopedia of Psychology and Gender . SAGE Publications. p. 401. ISBN 978-1483384276 . Most cultures currently construct their societies based on the understanding of gender binary – the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization. ^ Herdt, Gilbert (2020). "Third Sexes and Third Genders". Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . Princeton, NJ: Princeton University Press. pp. 21–83. ISBN 978-1-942130-52-9 . Retrieved 30 July 2022 . ^ Trumbach, Randolph (1994). "London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture". In Herdt, Gilbert (ed.). Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . New York: Zone (MIT). pp. 111–136. ISBN 978-0-942299-82-3 . ^ Graham, Sharyn (April–June 2001). "Sulawesi's fifth gender" . Inside Indonesia . Archived from the original on 26 November 2014. ^ Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John ; Nieder, Timo O.; T'Sjoen, Guy (2016). "Non-binary or genderqueer genders" . International Review of Psychiatry . 28 (1): 95–102. doi : 10.3109/09540261.2015.1106446 . hdl : 1854/LU-7279758 . PMID 26753630 . S2CID 29985722 . Archived from the original on 26 June 2019 . Retrieved 9 June 2019 . ^ Ananthaswamy, Anil; Douglas, Kate. "The origins of sexism: How men came to rule 12,000 years ago" . New Scientist . Retrieved 7 March 2023 . ^ "What do we mean by "sex" and "gender"?" . World Health Organization . Archived from the original on 30 January 2017 . Retrieved 26 November 2015 . ^ Alters S, Schiff W (2009). Essential Concepts for Healthy Living . Jones & Bartlett Publishers . p. 143. ISBN 978-0-7637-5641-3 . Retrieved 3 January 2018 . ^ Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy . 21 (3): 416–438. doi : 10.1093/oxrep/gri024 . ^ Dobres, Marcia-Anne (27 November 2020). "Gender in the Earliest Human Societies" . In Meade, Teresa A.; Wiesner-Hanks, Merry E. (eds.). A Companion to Global Gender History (1 ed.). Wiley. pp. 183–204. doi : 10.1002/9781119535812.ch11 . ISBN 978-1-119-53580-5 . S2CID 229399965 . Archived from the original on 10 June 2022 . Retrieved 10 June 2022 . ^ "The Nature of Kinship: Overview" . www2.palomar.edu . Archived from the original on 3 December 2020 . Retrieved 24 October 2020 . ^ Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition" . Proceedings of the National Academy of Sciences of the United States of America . 117 (5): 2378–2384. Bibcode : 2020PNAS..117.2378I . doi : 10.1073/pnas.1917716117 . PMC 7007516 . PMID 31964846 . ^ Chandra, Kanchan (2012). Constructivist theories of ethnic politics . Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7 . OCLC 829678440 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389. In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of 'us' and 'them.' In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population. ^ Blackmore E (22 February 2019). "Race and ethnicity: How are they different?" . Culture . Archived from the original on 22 October 2020 . Retrieved 24 October 2020 . ^ Chandra K (2006). "What is Ethnic Identity and Does It Matter?" . Annual Review of Political Science . 9 (1): 397–424. doi : 10.1146/annurev.polisci.9.062404.170715 . ISSN 1094-2939 . ^ Smith AD (1999). Myths and Memories of the Nation . Oxford University Press. pp. 4–7. ^ Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism . 13 (1): 19–35. doi : 10.1111/j.1469-8129.2007.00271.x . ^ Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism . London: Sage. p. 171. ISBN 978-1-4129-0101-7 . ^ Christian D (2004). Maps of Time . University of California Press. ISBN 978-0-520-24476-4 . ^ Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?" . SAPIENS . Archived from the original on 7 August 2020 . Retrieved 24 October 2020 . ^ Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit" . Proceedings of the National Academy of Sciences of the United States of America . 115 (19): E4532–E4540. Bibcode : 2018PNAS..115E4532Z . doi : 10.1073/pnas.1708960115 . PMC 5948950 . PMID 29674447 . S2CID 4993139 . ^ Melina R (14 February 2011). "What Are the Different Types of Governments?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 24 October 2020 . ^ "Democracy Index 2021: less than half the world lives in a democracy" . The Economist Democracy Index . Economist Intelligence Unit . February 10, 2022. ^ Jeannie Evers (23 December 2012). "international organization" . National Geographic Society . Archived from the original on 27 April 2017 . Retrieved 24 October 2020 . ^ Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization . 58 (1): 1–29. doi : 10.1016/j.jebo.2004.03.009 . ISSN 0167-2681 . ^ Gibbons J (11 August 2015). "Why did Neanderthals go extinct?" . Smithsonian Insider . Archived from the original on 12 November 2020 . Retrieved 11 October 2020 . ^ University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?" . www.newswise.com . Archived from the original on 1 February 2021 . Retrieved 11 October 2020 . ^ Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years" . inews.co.uk . Archived from the original on 23 January 2021 . Retrieved 11 October 2020 . ^ Henriques M. "How spices changed the ancient world" . www.bbc.com . Archived from the original on 25 January 2021 . Retrieved 11 October 2020 . ^ Strauss IE (26 February 2016). "The Myth of the Barter Economy" . The Atlantic . Archived from the original on 15 February 2021 . Retrieved 11 October 2020 . ^ "The History of Money" . www.pbs.org . 26 October 1996. Archived from the original on 29 November 2020 . Retrieved 11 October 2020 . ^ "Why do we need economists and the study of economics?" . Federal Reserve Bank of San Francisco . July 2000. Archived from the original on 12 November 2020 . Retrieved 23 October 2020 . ^ Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong" . New Scientist . Archived from the original on 3 February 2021 . Retrieved 24 October 2020 . ^ Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates" . The Atlantic . Archived from the original on 7 May 2021 . Retrieved 7 May 2021 . ^ Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature . 538 (7624): 233–237. Bibcode : 2016Natur.538..233G . doi : 10.1038/nature19758 . PMID 27680701 . S2CID 4454927 . ^ Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF) . Nature . 538 (7624): 180–181. Bibcode : 2016Natur.538..180P . doi : 10.1038/nature19474 . PMID 27680700 . S2CID 4459560 . Archived (PDF) from the original on 20 May 2022 . Retrieved 30 July 2022 . ^ Ferguson RB (1 September 2018). "War Is Not Part of Human Nature" . Scientific American . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Ferguson N (September–October 2006). "The Next War of the World" . Foreign Affairs . Archived from the original on 25 April 2022 . Retrieved 30 July 2022 . ^ Beauchamp, Zack (June 23, 2015). "600 years of war and peace, in one amazing chart" . Vox . External links Listen to this article ( 1 hour and 16 minutes ) This audio file was created from a revision of this article dated 11 January 2022 ( 2022-01-11 ) , and does not reflect subsequent edits. ( Audio help · More spoken articles ) v t e Human evolution Taxonomy ( Hominins ) Last common ancestors Chimpanzee–human Gorilla–human Orangutan–human Gibbon–human Australopithecines Nakalipithecus Orrorin Sahelanthropus Kenyanthropus Ardipithecus A. kadabba A. ramidus Australopithecus A. afarensis A. africanus A. anamensis A. bahrelghazali A. deyiremeda A. garhi A. sediba Paranthropus P. aethiopicus P. boisei P. robustus Humans and proto-humans ( Homo ) Proto-humans H. gautengensis (?) H. habilis H. naledi H. rudolfensis (?) H. tsaichangensis (?) Homo erectus H. e. erectus H. e. georgicus H. e. lantianensis H. e. nankinensis H. e. pekinensis H. e. soloensis H. e. tautavelensis H. e. yuanmouensis Archaic humans H. antecessor Denisovans H. ergaster (?) H. floresiensis H. heidelbergensis H. longi (?) H. luzonensis H. neanderthalensis H. rhodesiensis (?) Modern humans Homo sapiens H. s. sapiens (archaic homo sapiens, anatomically modern humans) Jebel Irhoud H. s. idaltu Cro-Magnon Manot people Tam Pa Ling Red Deer Cave people Ancestors Homo habilis → Homo ergaster / Homo erectus (→ Homo antecessor ) → Homo heidelbergensis → archaic Homo sapiens → Homo sapiens Models General models Hunting Gathering Endurance running Aquatic ape Sexual selection Self-domestication Specific models Diet Cooking Expensive tissue Shore-based Drugs Drunken monkey Evolutionary models of human drug use Stoned ape theory Behavior Killer ape Cooperative eye Life history Grandmother Patriarch Topics Bipedalism Skeleton Muscles Skin color Hair Thermoregulation Speech Language Intelligence Gender roles Origin of modern humans Recent African origin Multiregional origin Archaic admixture Behavioral modernity Early migrations Recent evolution Timelines Human evolution Human prehistory Human timeline Others Theorists Books Fossils Evolutionary anthropology Paleoanthropology Human evolutionary developmental biology Category Commons Evolutionary biology Portal v t e Extant species of family Hominidae (great apes) Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Hominidae Ponginae Pongo (Orangutans) Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Homininae Gorilla (Gorillas) Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Hominini Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Homo (Humans) Human ( H. sapiens ) Category v t e Apes Extant ape species Homo Human ( H. sapiens ) Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Gorilla Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Orangutan Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Gibbon ( family : Hylobatidae) Study of apes Great ape language Dian Fossey Birutė Galdikas Jane Goodall Chimpanzee genome project Human Genome Project Gladys Kalema-Zikusoka Neanderthal genome project Willie Smits Lone Drøscher Nielsen Ian Redmond Elgin Center Iowa Primate Learning Sanctuary Borneo Orangutan Survival Primate archaeology Legal and social status Personhood Research ban Kinshasa Declaration on Great Apes Great Ape Project Great Apes Survival Partnership International Primate Day Nonhuman Rights Project Related Primate List of individual apes (non-human) Apes in space (non-human) Bigfoot Bushmeat Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor Gibbon–human last common ancestor List of fictional primates (non-human) Great apes Human evolution Monkey Day Mythic humanoids Yeren Yeti Yowie Category Humans at Wikipedia's sister projects : Definitions from Wiktionary Media from Commons Quotations from Wikiquote Texts from Wikisource Taxa from Wikispecies Taxon identifiers Homo sapiens Wikidata : Q15978631 ADW : Homo_sapiens BOLD : 12439 CoL : 6MB3T EoL : 327955 EPPO : HOMXSA GBIF : 2436436 iNaturalist : 43584 IRMNG : 10857762 ITIS : 180092 MDD : 1000718 MSW : 12100795 NBN : NHMSYS0000376773 NCBI : 9606 NZOR: d83185ac-1aa6-4f59-8645-fe8c040857b3 Observation.org : 83981 OBIS : 1455977 Open Tree of Life : 770315 Paleobiology Database : 83088 TSA : 8319 WoRMS : 1455977 ZooBank : 58D31D52-713D-44B4-9FE9-CB2D9249C422 Authority control databases International FAST National France BnF data Germany Israel Czech Republic Korea Other Encyclopedia of Modern Ukraine NARA İslâm Ansiklopedisi Retrieved from " https://en.wikipedia.org/w/index.php?title=Human&oldid=1221314650 "
Species of hominid in the genus Homo Several terms redirect here. For other uses, see Human (disambiguation) , Mankind (disambiguation) , Humankind (disambiguation) , Human Race (disambiguation) , Human Being (disambiguation) , and Homo sapiens (disambiguation) . Human Temporal range: 0.3–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓ Chibanian – present Male (left) and female (right) adult humans, Thailand , 2007 Scientific classification Domain: Eukaryota Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Infraorder: Simiiformes Family: Hominidae Subfamily: Homininae Tribe: Hominini Genus: Homo Species: H. sapiens Binomial name Homo sapiens Linnaeus , 1758 Homo sapiens population density (2005) Humans ( Homo sapiens ) or modern humans are the most common and widespread species of primate , and the last surviving species of the genus Homo . They are great apes characterized by their hairlessness , bipedalism , and high intelligence . Humans have large brains , enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools , and form complex social structures and civilizations . Humans are highly social , with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states . As such, social interactions between humans have established a wide variety of values, social norms , languages , and traditions (collectively termed institutions ), each of which bolsters human society . Humans are also highly curious : the desire to understand and influence phenomena has motivated humanity's development of science , technology , philosophy , mythology , religion , and other frameworks of knowledge ; humans also study themselves through such domains as anthropology , social science , history , psychology , and medicine . As of April 2024, there are estimated to be more than 8 billion humans alive . Although some scientists equate the term "humans" with all members of the genus Homo , in common usage it generally refers to Homo sapiens , the only extant member. All other members of the genus Homo , which are now extinct, are known as archaic humans , and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa , they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence , interbreeding with Homo sapiens , or inability to adapt to climate change. For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution , which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement ; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change . Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle. Genes and the environment influence human biological variation in visible characteristics, physiology , disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic : generally, males have greater body strength and females have a higher body fat percentage. At puberty , humans develop secondary sex characteristics . Females are capable of pregnancy , usually between puberty, at around 12 years old, and menopause , around the age of 50. Humans are omnivorous , capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus . Humans can survive for up to eight weeks without food and several days without water . Humans are generally diurnal , sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death . Often, both the mother and the father provide care for their children, who are helpless at birth . Humans have a large, highly developed, and complex prefrontal cortex , the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory ; they have flexible facial expressions, self-awareness , and a theory of mind . The human mind is capable of introspection , private thought , imagination , volition , and forming views on existence . This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language . Etymology and definition Further information: Names for the human species and Human taxonomy Carl Linnaeus coined the name Homo sapiens All modern humans are classified into the species Homo sapiens , coined by Carl Linnaeus in his 1735 work Systema Naturae . The generic name " Homo " is a learned 18th-century derivation from Latin homō , which refers to humans of either sex. The word human can refer to all members of the Homo genus. The name " Homo sapiens " means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals , should be included as a separate species of humans or as a subspecies of H. sapiens . Human is a loanword of Middle English from Old French humain , ultimately from Latin hūmānus , the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity ) as well as to human males. It may also refer to individuals of either sex. Despite the fact that the word animal is colloquially used as an antonym for human , and contrary to a common biological misconception , humans are animals. The word person is often used interchangeably with human , but philosophical debate exists as to whether personhood applies to all humans or all sentient beings , and further if one can lose personhood (such as by going into a persistent vegetative state ). Evolution Main article: Human evolution Humans are apes ( superfamily Hominoidea ). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo ), then gorillas (genus Gorilla ), and finally, chimpanzees and bonobos (genus Pan ). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct. Reconstruction of Lucy , the first Australopithecus afarensis skeleton found The genus Homo evolved from Australopithecus . Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus . The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia , and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster ) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan . Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis , the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier. The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second ( Southern Dispersal ) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii , Easter Island , Madagascar , and New Zealand in the years 300 to 1280 CE. Human evolution was not a simple linear or branched progression but involved interbreeding between related species . Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans , may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans. Human evolution is characterized by a number of morphological , developmental , physiological , and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees . The most significant of these adaptations are hairlessness , obligate bipedalism, increased brain size and decreased sexual dimorphism ( neoteny ). The relationship between all these changes is the subject of ongoing debate. Hominoidea (hominoids, apes ) Hylobatidae ( gibbons ) Hominidae (hominids, great apes ) Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans) History Main article: Human history Prehistory Main article: Prehistory Overview map of the peopling of the world by early human migration during the Upper Paleolithic , following the Southern Dispersal paradigm Until about 12,000 years ago, all humans lived as hunter-gatherers . The Neolithic Revolution (the invention of agriculture ) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea , and the Sahel and West Savanna regions of Africa. Access to food surplus led to the formation of permanent human settlements , the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations . Ancient Main article: Ancient history Great Pyramids of Giza , Egypt An urban revolution took place in the 4th millennium BCE with the development of city-states , particularly Sumerian cities located in Mesopotamia . It was in these cities that the earliest known form of writing, cuneiform script , appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation . They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture , Minoans and the Shang dynasty , rose to prominence in new areas. The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages . During this period iron started replacing bronze, leading to the Iron Age . In the 5th century BCE, history started being recorded as a discipline , which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars . In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire 's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions. Medieval Main article: Post-classical history Medieval French manuscript illustration of the three classes of medieval society from the 13th-century Li Livres dou Santé Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages . During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age , inspiring achievements in architecture , the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England , the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims . In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast . Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific. Modern Main articles: Early modern period and Late modern period James Watt 's steam engine The early modern period in Europe and the Near East ( c. 1450 –1800) began with the final defeat of the Byzantine Empire , and the rise of the Ottoman Empire . Meanwhile, Japan entered the Edo period , the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance , starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas . This expansion led to the Atlantic slave trade and the genocide of Native American peoples . This period also marked the Scientific Revolution , with great advances in mathematics , mechanics , astronomy and physiology . The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology , major innovations in transport and energy development . The United States of America underwent great change, going from a small group of colonies to one of the global superpowers . The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World , while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania. A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War , one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War , involving almost all of the world's countries . The war's destruction led to the collapse of most global empires, leading to widespread decolonization. Contemporary Main article: Contemporary history Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race , ending in the collapse of the Soviet Union. The current Information Age , spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected. Habitat and population Further information: Human geography and Demography Population statistics Choropleth showing Population density (people per square kilometer) estimates by 30 arc-second grid in 2020 World population 8.1 billion Population density 16/km (41/sq mi) by total area 54/km (140/sq mi) by land area Largest cities Tokyo , Delhi , Shanghai , São Paulo , Mexico City , Cairo , Mumbai , Beijing , Dhaka , Osaka , New York - Newark , Karachi , Buenos Aires , Chongqing , Istanbul , Kolkata , Manila , Lagos , Rio de Janeiro , Tianjin , Kinshasa , Guangzhou , Los Angeles - Long Beach - Santa Ana , Moscow , Shenzhen , Lahore , Bangalore , Paris , Jakarta , Chennai , Lima , Bogota , Bangkok , London Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence , such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation , urban planning , construction, deforestation and desertification . Human settlements continue to be vulnerable to natural disasters , especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics , increasing knowledge or enhancing the exchange of resources. Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms , although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa , India , Russia , Australia , Fiji , United States and Brazil (each located in a different biogeographical realm). By using advanced tools and clothing , humans have been able to extend their tolerance to a wide variety of temperatures, humidities , and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest , arid desert , extremely cold arctic regions , and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth 's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%). Within the last century, humans have explored challenging environments such as Antarctica, the deep sea , and outer space . Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific , military , or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft . Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station . Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%. Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues , first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals. In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums . Humans have had a dramatic effect on the environment . They are apex predators , being rarely preyed upon by other species. Human population growth , industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life. Biology Anatomy and physiology Main article: Human body Basic anatomical features of female and male humans. These models have had body hair and male facial hair removed and head hair trimmed. Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.3 2.1.2.3 . Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth . Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars , with some individuals having them congenitally absent. Humans share with chimpanzees a vestigial tail, appendix , flexible shoulder joints, grasping fingers and opposable thumbs . Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling , hearing and digesting proteins . While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair , most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet. It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged . Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals. Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger. Genetics Main article: Human genetics A graphical representation of the standard human karyotype , including both the female (XX) and male (XY) sex chromosomes. Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes , each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes . Like other mammals, humans have an XY sex-determination system , so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood. While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years. The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms . African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas . By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA , which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve , must have lived around 90,000 to 200,000 years ago. Life cycle See also: Childbirth and Life expectancy A 10 mm human embryo at 5 weeks Most human reproduction takes place by internal fertilization via sexual intercourse , but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus . Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions. Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries. Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth , humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy , childhood , adolescence , adulthood and old age . The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis ), rather than by continuing to bear children into old age. The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018 , the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic , it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world , the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide. Human life stages Infant boy and girl Boy and girl before puberty ( children ) Adolescent male and female Adult man and woman Elderly man and woman Diet Main article: Human nutrition Humans living in Bali , Indonesia , preparing a meal Humans are omnivorous , capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous . In some cases, dietary restrictions in humans can lead to deficiency diseases ; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science . Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game , which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus . Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture , a gradual process called the Neolithic Revolution . These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture. In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation . Childhood malnutrition is also common and contributes to the global burden of disease . However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries . Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an " obesity epidemic ." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet. Biological variation Main article: Human genetic variation A Libyan , a Nubian , a Syrian , and an Egyptian , drawing by an unknown artist after a mural of the tomb of Seti I There is biological variation in the human species – with traits such as blood type , genetic diseases , cranial features , facial features , organ systems , eye color , hair color and texture , height and build , and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin , and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet , exercise, and sleep patterns . A variety of human hair colors; from top left, clockwise: black , brown , blonde , white , red . There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk . Sickle cell anemia , which may provide increased resistance to malaria , is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions , tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes . Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau . Human hair ranges in color from red to blond to brown to black , which is the most frequent. Hair color depends on the amount of melanin , with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach , or even nearly white or colorless in cases of albinism . It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D , which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation. There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other. Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa , and particularly West Africa , have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans. Humans are a gonochoric species, meaning they are divided into male and female sexes . The greatest degree of genetic variation exists between males and females . While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation . As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare. Psychology Main article: Psychology Drawing of the human brain , showing several important structures The human brain , the focal point of the central nervous system in humans, controls the peripheral nervous system . In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion , it is also the locus of "higher" order functioning such as thought , reasoning , and abstraction . These cognitive processes constitute the mind , and, along with their behavioral consequences, are studied in the field of psychology . Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition . This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to. There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in " mental time travel ". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind . Sleep and dreaming Main articles: Sleep and Dream Humans are generally diurnal . The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort. During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep . The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming , where the dreamer is self-aware . Dreams can at times make a creative thought occur or give a sense of inspiration . Consciousness and thought Main articles: Consciousness and Cognition Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection , private thought , imagination and volition . It now often includes some kind of experience , cognition , feeling or perception . It may be 'awareness', or ' awareness of awareness ', or self-awareness . There might be different levels or orders of consciousness , or different kinds of consciousness, or just one kind with different features. The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses , and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition , the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development . Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population. Motivation and emotion Main articles: Motivation and Emotion Illustration of grief from Charles Darwin 's 1872 book The Expression of the Emotions in Man and Animals Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization . Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure . They are often intertwined with mood , temperament , personality , disposition , creativity , and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal. Emotional experiences perceived as pleasant , such as joy , interest or contentment , contrast with those perceived as unpleasant , like anxiety , sadness , anger , and despair . Happiness , or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects , while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life . Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted. Sexuality and love Main articles: Human sexuality and Love Human parents often display familial love for their children. For humans, sexuality involves biological , erotic , physical , emotional , social , or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions , including the human sexual response cycle . Sexuality also affects and is affected by cultural, political, legal, philosophical, moral , ethical , and religious aspects of life. Sexual desire, or libido , is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often. Humans can fall anywhere along a continuous scale of sexual orientation , although most humans are heterosexual . While homosexual behavior occurs in some other animals , only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation , as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well. Love most commonly refers to a feeling of strong attraction or emotional attachment . It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine , norepinephrine , serotonin and other chemicals stimulate the brain's pleasure center , leading to side effects such as increased heart rate , loss of appetite and sleep , and an intense feeling of excitement . Culture Main articles: Culture and Cultural universal Human society statistics Most widely spoken languages English , Mandarin Chinese , Hindi , Spanish , Standard Arabic , Bengali , French , Russian , Portuguese , Urdu Most practiced religions Christianity , Islam , Hinduism , Buddhism , folk religions , Sikhism , Judaism , unaffiliated Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the " folk physics " required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning . Language Main article: Language Principal language families of the world (and in some cases geographic groups of families). For greater detail, see Distribution of languages in the world . While many species communicate , language is unique to humans, a defining feature of humanity, and a cultural universal . Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement , using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors. Language differs from other forms of communication in that it is modality independent ; the same meanings can be conveyed through different media, audibly in speech , visually by sign language or writing, and through tactile media such as braille . Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct . The arts Main article: The arts Human arts can take many forms including visual , literary , and performing . Visual art can range from paintings and sculptures to film , fashion design , and architecture . Literary arts can include prose , poetry , and dramas . The performing arts generally involve theatre , music , and dance . Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation , video games , and medicine . As well as providing entertainment and transferring knowledge, the arts are also used for political purposes . The Deluge tablet of the Gilgamesh epic in Akkadian Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage. Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures . There exists a wide variety of music genres and ethnic musics ; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment . Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain. Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh , first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation. Tools and technologies Main articles: Tool and Technology The SCMaglev , the fastest train in the world clocking in at 603 km/h (375 mph) as of 2015 Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated , thus proving essential in the development of agriculture – what is known as the Neolithic Revolution . China developed paper , the printing press , gunpowder , the compass and other important inventions . The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel , which is used in railways , skyscrapers and many other products. This coincided with the Industrial Revolution , where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially , with major innovations in the 20th century including: electricity , penicillin , semiconductors , internal combustion engines , the Internet , nitrogen fixing fertilisers , airplanes , computers , automobiles , contraceptive pills , nuclear fission , the green revolution , radio , scientific plant breeding , rockets , air conditioning , television and the assembly line . Religion and spirituality Main articles: Religion and Spirituality Shango , the Orisha of fire, lightning, and thunder, in the Yoruba religion , depicted on horseback Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural , sacred or divine , and practices, values , institutions and rituals associated with such belief. Some religions also have a moral code . The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago ). It may have evolved to play a role in helping enforce and encourage cooperation between humans. Religion manifests in diverse forms. Religion can include a belief in life after death , the origin of life , the nature of the universe ( religious cosmology ) and its ultimate fate ( eschatology ), and moral or ethical teachings . Views on transcendence and immanence vary substantially; traditions variously espouse monism , deism , pantheism , and theism (including polytheism and monotheism ). Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims , Hindus and Buddhists . As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious , including those with no religious beliefs or no identity with any religion. Science and philosophy Main articles: Science and Philosophy The Dunhuang map , a star map showing the North Polar region. China circa 700. An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy. Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period . Other early advances in science came from the Han dynasty in China and during the Islamic Golden Age . The scientific revolution , near the end of the Renaissance , led to the emergence of modern science . A chain of events and influences led to the development of the scientific method , a process of observation and experimentation that is used to differentiate science from pseudoscience . An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition . All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics ), which are concerned with formal systems , the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics , chemistry , biology ) and social sciences (e.g., psychology , economics, sociology). Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics , epistemology , logic , and axiology (which includes ethics and aesthetics ). Society Main article: Society Humans often live in family-based social structures Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power , reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies . Gender Main article: Gender Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex . The most common categorisation is a gender binary of men and women . Some societies recognise a third gender , or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female. Gender roles are often associated with a division of norms , practices , dress , behavior , rights , duties , privileges , status , and power , with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct , gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic , while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal. Kinship Main article: Kinship All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants ( consanguinity ), and relations through marriage ( affinity ). There is also a third type applied to godparents or adoptive children ( fictive ). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance . All societies have rules of incest taboo , according to which marriage between certain kinds of kin relations is prohibited, and some also have rules of preferential marriage with certain kin relations. Ethnicity Main article: Ethnic group Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry , language , history , society , culture , nation , religion , or social treatment within their residing area. Ethnicity is separate from the concept of race , which is based on physical characteristics, although both are socially constructed . Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries. Government and politics Main articles: Government and Politics The United Nations headquarters in New York City, which houses one of the world's largest political organizations As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances. Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy , 17% in a hybrid regime , and 37% in an authoritarian regime . Many countries belong to international organizations and alliances ; the largest of these is the United Nations , with 193 member states . Trade and economics Main articles: Trade and Economics The Silk Road (red) and spice trade routes (blue) Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian . The first truly international trade routes were around the spice trade through the Roman and medieval periods. Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities ; the oldest being in the form of cattle and the most widely used being cowrie shells . Money has since evolved into governmental issued coins , paper and electronic money . Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population. Conflict Main article: Conflict (process) American troops landing at Normandy , WWII. Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered , rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations, with rates of homicide about 0.01% in societies that have legal systems and strong cultural attitudes against violence. The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war ) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict. See also Mammals portal Evolutionary biology portal Science portal List of human evolution fossils Timeline of human evolution Notes ^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects. ^ Cities with over 10 million inhabitants as of 2018. ^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that. References ^ Groves CP (2005). Wilson DE , Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4 . OCLC 62265494 . ^ Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences . 149 (1): 109–114. JSTOR 4065043 . ^ Porkorny (1959). IEW . s.v. "g'hðem" pp. 414–116. ^ "Homo" . Dictionary.com Unabridged (v 1.1) . Random House. 23 September 2008. Archived from the original on 27 September 2008. ^ Barras, Colin (11 January 2016). "We don't know which species should be classed as 'human' " . BBC . Archived from the original on 26 August 2021 . Retrieved 31 March 2021 . ^ Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758" . Proceedings of the Academy of Natural Sciences of Philadelphia . 149 : 109–114. ISSN 0097-3157 . JSTOR 4065043 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . ^ OED . s.v. "human". ^ "Man" . Merriam-Webster Dictionary . Archived from the original on 22 September 2017 . Retrieved 14 September 2017 . Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination ^ "Thesaurus results for human" . Merriam-Webster Dictionary . Archived from the original on 28 June 2022 . Retrieved 21 May 2022 . ^ "Misconceptions about evolution – Understanding Evolution" . University of California, Berkeley . 19 September 2021. Archived from the original on 6 June 2022 . Retrieved 21 May 2022 . ^ "Concept of Personhood" . University of Missouri School of Medicine . Archived from the original on 4 March 2021 . Retrieved 4 July 2021 . ^ Tuttle RH (4 October 2018). "Hominoidea: conceptual history" . In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology . Hoboken , New Jersey , United States : John Wiley & Sons, Inc. pp. 1–2. doi : 10.1002/9781118584538.ieba0246 . ISBN 978-1-118-58442-2 . S2CID 240125199 . Retrieved 26 May 2021 . ^ Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution . 30 (3): 260–266. Bibcode : 1990JMolE..30..260G . doi : 10.1007/BF02099995 . PMID 2109087 . S2CID 2112935 . ^ Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets" . Molecular Biology and Evolution . 14 (3): 248–265. doi : 10.1093/oxfordjournals.molbev.a025761 . PMID 9066793 . ^ MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes" . Evolution pages . Archived from the original on 9 August 2011 . Retrieved 18 May 2006 . ^ McNulty, Kieran P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?" . Nature Education Knowledge . Archived from the original on 10 January 2016 . Retrieved 11 June 2022 . ^ Strait DS (September 2010). "The Evolutionary History of the Australopiths" . Evolution: Education and Outreach . 3 (3): 341–352. doi : 10.1007/s12052-010-0249-6 . ISSN 1936-6434 . S2CID 31979188 . ^ Dunsworth HM (September 2010). "Origin of the Genus Homo" . Evolution: Education and Outreach . 3 (3): 353–366. doi : 10.1007/s12052-010-0247-8 . ISSN 1936-6434 . S2CID 43116946 . ^ Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1698): 20150248. doi : 10.1098/rstb.2015.0248 . PMC 4920303 . PMID 27298460 . S2CID 20267830 . ^ Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia" . Science . 347 (6228): 1352–1355. Bibcode : 2015Sci...347.1352V . doi : 10.1126/science.aaa1343 . PMID 25739410 . ^ Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature . 559 (7715): 608–612. Bibcode : 2018Natur.559..608Z . doi : 10.1038/s41586-018-0299-4 . PMID 29995848 . S2CID 49670311 . ^ Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF) . Nature . 546 (7657): 289–292. Bibcode : 2017Natur.546..289H . doi : 10.1038/nature22336 . PMID 28593953 . S2CID 256771372 . Archived (PDF) from the original on 8 January 2020 . Retrieved 30 July 2022 . ^ "Out of Africa Revisited". Science (This Week in Science ). 308 (5724): 921. 13 May 2005. doi : 10.1126/science.308.5724.921g . ISSN 0036-8075 . S2CID 220100436 . ^ Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature . 423 (6941): 692–693, 695. Bibcode : 2003Natur.423..692S . doi : 10.1038/423692a . PMID 12802315 . S2CID 26693109 . ^ Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?" . actionbioscience . Washington, DC: American Institute of Biological Sciences . Archived from the original on 17 June 2021 . Retrieved 23 November 2009 . ^ Marean, Curtis; et al. (2007). "Early human use of marine resources and pigment in South Africa during the Middle Pleistocene" (PDF) . Nature . 449 (7164): 905–908. Bibcode : 2007Natur.449..905M . doi : 10.1038/nature06204 . PMID 17943129 . S2CID 4387442 . Archived (PDF) from the original on 2023-05-25 . Retrieved 2023-01-07 . ^ Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB (2018). "Long-distance stone transport and pigment use in the earliest Middle Stone Age" . Science . 360 (6384): 90–94. Bibcode : 2018Sci...360...90B . doi : 10.1126/science.aao2646 . PMID 29545508 . ^ Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology . 26 (6): 827–833. Bibcode : 2016CBio...26..827P . doi : 10.1016/j.cub.2016.01.037 . hdl : 2440/114930 . PMID 26853362 . S2CID 140098861 . ^ Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture" . Genome Research . 25 (4): 459–466. doi : 10.1101/gr.186684.114 . PMC 4381518 . PMID 25770088 . ^ Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia" . Science . 331 (6016): 453–456. Bibcode : 2011Sci...331..453A . doi : 10.1126/science.1199113 . PMID 21273486 . S2CID 20296624 . Archived from the original on 27 April 2011 . Retrieved 1 May 2011 . ^ Rincon P (27 January 2011). "Humans 'left Africa much earlier' " . BBC News . Archived from the original on 9 August 2012. ^ Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature . 547 (7663): 306–310. Bibcode : 2017Natur.547..306C . doi : 10.1038/nature22968 . hdl : 2440/107043 . PMID 28726833 . S2CID 205257212 . ^ Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF) . University of Waikato . Archived (PDF) from the original on 22 May 2010 . Retrieved 29 April 2010 . ^ Appenzeller T (May 2012). "Human migrations: Eastern odyssey" . Nature . 485 (7396): 24–26. Bibcode : 2012Natur.485...24A . doi : 10.1038/485024a . PMID 22552074 . ^ Reich D , Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" . Nature . 468 (7327): 1053–1060. Bibcode : 2010Natur.468.1053R . doi : 10.1038/nature09710 . hdl : 10230/25596 . PMC 4306417 . PMID 21179161 . ^ Hammer MF (May 2013). "Human Hybrids" (PDF) . Scientific American . 308 (5): 66–71. Bibcode : 2013SciAm.308e..66H . doi : 10.1038/scientificamerican0513-66 . PMID 23627222 . Archived from the original (PDF) on 24 August 2018. ^ Yong E (July 2011). "Mosaic humans, the hybrid species" . New Scientist . 211 (2823): 34–38. Bibcode : 2011NewSc.211...34Y . doi : 10.1016/S0262-4079(11)61839-3 . ^ Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology . 43 (1): 1–11. doi : 10.1007/s11692-015-9348-1 . S2CID 14329491 . ^ Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans" . Genome Research . 20 (5): 547–553. doi : 10.1101/gr.076000.108 . PMC 2860157 . PMID 20439435 . ^ Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans" . Science . 334 (6052): 89–94. Bibcode : 2011Sci...334...89A . doi : 10.1126/science.1209202 . PMC 3677943 . PMID 21868630 . ^ Sandel, Aaron A. (30 July 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness" . American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . Archived from the original on 22 July 2023 . Retrieved 22 July 2023 . ^ Boyd R , Silk JB (2003). How Humans Evolved . New York: Norton . ISBN 978-0-393-97854-4 . ^ Little, Michael A.; Blumler, Mark A. (2015). "Hunter-Gatherers" . In Muehlenbein, Michael P. (ed.). Basics in Human Evolution . Boston: Academic Press. pp. 323–335. ISBN 978-0-12-802652-6 . Archived from the original on 3 July 2022 . Retrieved 30 July 2022 . ^ Scarre, Chris (2018). "The world transformed: from foragers and farmers to states and empires". In Scarre, Chris (ed.). The Human Past: World Prehistory and the Development of Human Societies (4th ed.). London: Thames & Hudson . pp. 174–197. ISBN 978-0-500-29335-5 . ^ Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe . Walnut Creek, CA: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5 . OCLC 855969933 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society . Elsevier. pp. 103–131. doi : 10.1016/B978-0-12-805247-1.00006-X . ISBN 978-0-12-805247-1 . ^ He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China" . The Holocene . 27 (12): 1885–1898. Bibcode : 2017Holoc..27.1885H . doi : 10.1177/0959683617708455 . S2CID 133660098 . Archived from the original on 20 November 2021 . Retrieved 30 July 2022 . ^ Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago" . Proceedings of the National Academy of Sciences of the United States of America . 106 (18): 7367–7372. Bibcode : 2009PNAS..106.7367L . doi : 10.1073/pnas.0900158106 . PMC 2678631 . PMID 19383791 . ^ Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea" . Science . 301 (5630): 189–193. doi : 10.1126/science.1085255 . PMID 12817084 . S2CID 10644185 . ^ Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication" . Science Advances . 5 (5): eaaw1947. Bibcode : 2019SciA....5.1947S . doi : 10.1126/sciadv.aaw1947 . PMC 6527260 . PMID 31114806 . ^ Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF) . Current Anthropology . 58 (5): 673–683. doi : 10.1086/693898 . S2CID 149402650 . Archived (PDF) from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science . 38 (2): 312–322. Bibcode : 2011JArSc..38..312M . doi : 10.1016/j.jas.2010.09.007 . ^ Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries . Cengage Learning. ISBN 978-1-285-66153-7 . Archived from the original on 27 February 2021 . Retrieved 11 July 2015 . ^ Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500 . Cenpage Learning. ISBN 978-1-285-98299-1 . Archived from the original on 10 August 2023 . Retrieved 11 July 2015 . ^ Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization . San Francisco: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3 . Archived from the original on 10 August 2023 . Retrieved 30 July 2022 . ^ Garfinkle, Steven J. (2013). "Ancient Near Eastern City-States". In Peter Fibiger Bang ; Walter Scheidel (eds.). The Oxford Handbook of the State in the Ancient Near East and Mediterranean . Oxford Academic. pp. 94–119. doi : 10.1093/oxfordhb/9780195188318.013.0004 . ISBN 978-0-19-518831-8 . ^ Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi : 10.1002/9781119193814.ch2 . ISBN 978-1-119-19329-6 . S2CID 216180781 . ^ Robinson A (October 2015). "Ancient civilization: Cracking the Indus script" . Nature . 526 (7574): 499–501. Bibcode : 2015Natur.526..499R . doi : 10.1038/526499a . PMID 26490603 . S2CID 4458743 . ^ Crawford H (2013). "Trade in the Sumerian world". The Sumerian World . Routledge. pp. 447–461. ISBN 978-1-136-21911-5 . ^ Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles" . Acta Archaeologica Academiae Scientiarum Hungaricae . 69 (2): 271–298. doi : 10.1556/072.2018.69.2.3 . ISSN 0001-5210 . S2CID 115685157 . Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Pryor FL (1985). "The Invention of the Plow" . Comparative Studies in Society and History . 27 (4): 727–743. doi : 10.1017/S0010417500011749 . ISSN 0010-4175 . JSTOR 178600 . S2CID 144840498 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Carter R (2012). "19. Watercraft ". In Potts DT (ed.). A companion to the archaeology of the ancient Near East . Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0 . Archived from the original on 28 April 2015 . Retrieved 8 February 2014 . ^ Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction . CUP Archive. p. 1. ISBN 978-0-521-40340-5 . ^ Robson E (2008). Mathematics in ancient Iraq: A social history . Princeton University Press. pp. xxi. ^ Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza" . Technology and Culture . 44 (2): 340–354. doi : 10.1353/tech.2003.0063 . ISSN 0040-165X . JSTOR 25148110 . S2CID 109998651 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Voosen P (August 2018). "New geological age comes under fire". Science . 361 (6402): 537–538. Bibcode : 2018Sci...361..537V . doi : 10.1126/science.361.6402.537 . PMID 30093579 . S2CID 51954326 . ^ Saggs HW (2000). Babylonians . Univ of California Press. p. 7. ISBN 978-0-520-20222-1 . ^ Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory . 12 (4): 335–364. doi : 10.1007/s10816-005-8460-4 . ISSN 1573-7764 . S2CID 53393440 . ^ Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans" . Nature . 548 (7666): 214–218. Bibcode : 2017Natur.548..214L . doi : 10.1038/nature23310 . PMC 5565772 . PMID 28783727 . ^ Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC . Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8 . ^ Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change . 6 (4): 369–382. Bibcode : 2015WIRCC...6..369K . doi : 10.1002/wcc.345 . S2CID 128460316 . ^ Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science . 39 (6): 1862–1870. Bibcode : 2012JArSc..39.1862D . doi : 10.1016/j.jas.2012.01.029 . ^ Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory . Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi : 10.1007/978-1-4419-6633-9_11 . ISBN 978-1-4419-6633-9 . ^ Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography . United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1 . ^ Beard M (2 October 2015). "Why ancient Rome matters to the modern world" . The Guardian . Archived from the original on 14 April 2021 . Retrieved 17 April 2021 . ^ Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece" . Stanford University . Archived from the original on 18 April 2021 . Retrieved 17 April 2021 . ^ Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature . 582 (7813): 530–533. Bibcode : 2020Natur.582..530I . doi : 10.1038/s41586-020-2343-4 . PMID 32494009 . S2CID 219281856 . ^ Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar" . Latin American Antiquity . 28 (1): 88–104. doi : 10.1017/laq.2016.4 . ISSN 1045-6635 . S2CID 164417025 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida" . Proceedings of the Seminar for Arabian Studies . 46 : 25–40. ISSN 0308-8421 . JSTOR 45163415 . Archived from the original on 28 April 2022 . Retrieved 30 July 2022 . ^ Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration . 21 (1): 25–86. doi : 10.1080/01900699808525297 . ISSN 0190-0692 . ^ Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age" . Journal of the American Oriental Society . 96 (1): 15–26. doi : 10.2307/599886 . ISSN 0003-0279 . JSTOR 599886 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty" . Architectural History . 63 : 1–36. doi : 10.1017/arh.2020.1 . ISSN 0066-622X . S2CID 229716130 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question" . Climate . 6 (4): 90. Bibcode : 2018Clim....6...90M . doi : 10.3390/cli6040090 . ^ Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World . New York: Oxford University Press. p. 72. ISBN 978-0-19-532819-6 . Retrieved 30 July 2022 . ^ Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies . International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi : 10.1007/978-3-319-24774-8_2 . ISBN 978-3-319-24774-8 . ^ Vidal-Nanquet P (1987). The Harper Atlas of World History . Harper & Row Publishers. p. 76. ^ Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land . Simon and Schuster. ISBN 978-1-84983-770-5 . ^ Adam King (2002). "Mississippian Period: Overview" . New Georgia Encyclopedia . Archived from the original on 19 August 2009 . Retrieved 15 November 2009 . ^ Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism . Cambridge University Press. p. 2. ISBN 0-521-31896-3 . ^ May T (2013). The Mongol Conquests in World History . Reaktion Books. p. 7. ISBN 978-1-86189-971-2 . ^ Canós-Donnay S (25 February 2019). "The Empire of Mali" . Oxford Research Encyclopedia of African History . Oxford University Press. doi : 10.1093/acrefore/9780190277734.013.266 . ISBN 978-0-19-027773-4 . Archived from the original on 20 October 2021 . Retrieved 7 May 2021 . ^ Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity" . Asian Perspectives . 37 (2): 135–164. ^ Kafadar C (1 January 1994). "Ottomans and Europe" . In Brady T, Oberman T, Tracy JD (eds.). Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation . Brill. pp. 589–635. doi : 10.1163/9789004391659_019 . ISBN 978-90-04-39165-9 . Archived from the original on 2 May 2022 . Retrieved 17 April 2021 . ^ Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan" . Oxford Research Encyclopedia of Asian History . Oxford University Press. doi : 10.1093/acrefore/9780190277727.013.72 . ISBN 978-0-19-027772-7 . Archived from the original on 12 August 2021 . Retrieved 7 May 2021 . ^ Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing" . Pacific Affairs . 83 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526–1857)" . Al-Ta Lim Journal . 23 (2): 128–138. doi : 10.15548/jt.v23i2.228 . ISSN 2355-7893 . Archived from the original on 7 April 2022 . Retrieved 30 July 2022 . ^ Kirkpatrick R (2002). The European Renaissance, 1400–1600 . Routledge. p. 1. ISBN 978-1-317-88646-4 . OCLC 893909816 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Arnold D (2002). The Age of Discovery, 1400–1600 (Second ed.). Routledge. pp. xi. ISBN 978-1-136-47968-7 . OCLC 859536800 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics" . Theoretical Inquiries in Law . 11 (1). doi : 10.2202/1565-3404.1239 . ISSN 1565-3404 . S2CID 56216309 . Archived from the original on 26 August 2021 . Retrieved 30 July 2022 . ^ Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews . 20 (1–3): 277–299. Bibcode : 2001QSRv...20..277J . doi : 10.1016/S0277-3791(00)00116-5 . ^ Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature" . The Journal of African History . 30 (3): 365–394. doi : 10.1017/S0021853700024439 . ISSN 0021-8537 . JSTOR 182914 . S2CID 161321949 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide . London: Palgrave Macmillan UK. pp. 273–295. doi : 10.1057/9780230297784_11 . ISBN 978-0-230-29778-4 . ^ Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour . 38 (3–4): 157–158. doi : 10.1016/j.endeavour.2014.10.001 . PMID 25457642 . ^ "Greatest Engineering Achievements of the 20th Century" . National Academy of Engineering . Archived from the original on 6 April 2015 . Retrieved 7 April 2015 . ^ Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776 . New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0 . OCLC 299054528 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815" . Journal of Global History . 1 (1): 123–149. doi : 10.1017/S1740022806000076 . ISSN 1740-0228 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Zimmerman AF (November 1931). "Spain and Its Colonies, 1808–1820" . The Hispanic American Historical Review . 11 (4): 439–463. doi : 10.2307/2506251 . JSTOR 2506251 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ David S (2011). "British History in depth: Slavery and the 'Scramble for Africa' " . BBC . Archived from the original on 24 March 2022 . Retrieved 5 May 2021 . ^ Raudzens G (2004). "The Australian Frontier Wars, 1788–1838 (review)" . The Journal of Military History . 68 (3): 957–959. doi : 10.1353/jmh.2004.0138 . ISSN 1543-7795 . S2CID 162259092 . ^ Clark CM (2012). "Polarization of Europe, 1887–1907". The sleepwalkers : how Europe went to war in 1914 . London: Allen Lane. ISBN 978-0-7139-9942-6 . OCLC 794136314 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Robert Dahl (1989). Democracy and Its Critics . Yale UP. pp. 239–240 . ISBN 0-300-15355-4 . ^ McDougall WA (May 1985). "Sputnik, the space race, and the Cold War" . Bulletin of the Atomic Scientists . 41 (5): 20–25. Bibcode : 1985BuAtS..41e..20M . doi : 10.1080/00963402.1985.11455962 . ISSN 0096-3402 . ^ Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?" . Journal of Peace Research . 30 (2): 163–179. doi : 10.1177/0022343393030002004 . ISSN 0022-3433 . S2CID 5482851 . Archived from the original on 21 February 2022 . Retrieved 30 July 2022 . ^ Sachs JD (April 2017). "Globalization – In the Name of Which Freedom?" . Humanistic Management Journal . 1 (2): 237–252. doi : 10.1007/s41463-017-0019-5 . ISSN 2366-603X . S2CID 133030709 . ^ "World" . The World Factbook . CIA . 17 May 2016. Archived from the original on 26 January 2021 . Retrieved 2 October 2016 . ^ "World Population Prospects: The 2017 Revision" (PDF) . United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17. Archived (PDF) from the original on 26 June 2019 . Retrieved 30 July 2022 . ^ "The World's Cities in 2018" (PDF) . United Nations . Archived (PDF) from the original on 1 November 2018. ^ Rector RK (2016). The Early River Valley Civilizations (First ed.). New York: Rosen Publishing. p. 10. ISBN 978-1-4994-6329-3 . OCLC 953735302 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ "How People Modify the Environment" (PDF) . Westerville City School District . Archived (PDF) from the original on 25 February 2021 . Retrieved 13 March 2019 . ^ "Natural disasters and the urban poor" (PDF) . World Bank . October 2003. Archived (PDF) from the original on 9 August 2017. ^ Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities . [London]: Routledge. pp. x. ISBN 978-1-135-01559-6 . OCLC 889953315 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Piantadosi CA (2003). The biology of human survival : life and death in extreme environments . Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5 . OCLC 70215878 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Toups, M.A.; Kitchen, A.; Light, J.E.; Reed, D.L. (2011). "Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa" . Molecular Biology and Evolution . 28 (1): 29–32. doi : 10.1093/molbev/msq234 . PMC 3002236 . PMID 20823373 . ^ O'Neil D. "Human Biological Adaptability; Overview" . Palomar College. Archived from the original on 6 March 2013 . Retrieved 6 January 2013 . ^ "Population distribution and density" . BBC. Archived from the original on 23 June 2017 . Retrieved 26 June 2017 . ^ Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management . 30 (4): 492–507. doi : 10.1007/s00267-002-2737-0 . hdl : 10072/6758 . PMID 12481916 . S2CID 25834286 . ^ Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica" . Vanderbilt Journal of Transnational Law . 23 : 819. Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ "Mission to Mars: Mars Science Laboratory Curiosity Rover" . Jet Propulsion Laboratory. Archived from the original on 18 August 2015 . Retrieved 26 August 2015 . ^ "Touchdown! Rosetta's Philae probe lands on comet" . European Space Agency. 12 November 2014. Archived from the original on 22 August 2015 . Retrieved 26 August 2015 . ^ "NEAR-Shoemaker" . NASA . Archived from the original on 26 August 2015 . Retrieved 26 August 2015 . ^ Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station" . JSC Features . Johnson Space Center . Archived from the original on 16 February 2012 . Retrieved 13 February 2012 . ^ Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth" . Proceedings of the National Academy of Sciences of the United States of America . 115 (25): 6506–6511. Bibcode : 2018PNAS..115.6506B . doi : 10.1073/pnas.1711842115 . PMC 6016768 . PMID 29784790 . ^ Tellier LN (2009). Urban world history: an economic and geographical perspective . Presses de l'Université du Québec. p. 26. ISBN 978-2-7605-1588-8 . Retrieved 30 July 2022 . ^ Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, CA: Dickenson Pub. Co. ISBN 978-0-8221-0166-6 . ^ Harl KW (1998). "Population estimates of the Roman Empire" . Tulane.edu. Archived from the original on 7 May 2016 . Retrieved 8 December 2012 . ^ Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis" . International Journal of Hygiene and Environmental Health . 207 (2): 165–178. doi : 10.1078/1438-4639-00259 . PMC 7128933 . PMID 15031959 . ^ "World's population reaches six billion" . BBC News . 5 August 1999. Archived from the original on 15 April 2008 . Retrieved 5 February 2008 . ^ United Nations. "World population to reach 8 billion on 15 November 2022" . United Nations . Archived from the original on 20 January 2023 . Retrieved 27 October 2022 . ^ "Eight billion people, SARS-CoV-2 ancestor and illegal fishing" . Nature . 611 (641): 641. 23 November 2022. Bibcode : 2022Natur.611..641. . doi : 10.1038/d41586-022-03792-4 . S2CID 253764233 . Archived from the original on 26 January 2023 . Retrieved 26 January 2023 . ^ "World Population to Hit Milestone With Birth of 7 Billionth Person" . PBS NewsHour . 27 October 2011. Archived from the original on 24 September 2017 . Retrieved 11 February 2018 . ^ "68% of the world population projected to live in urban areas by 2050, says UN" . United Nations Department of Economic and Social Affairs (DESA) . 16 May 2018. Archived from the original on 10 March 2021 . Retrieved 18 April 2021 . ^ Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF) . U.S. Department of Justice , Bureau of Justice Statistics. Archived (PDF) from the original on 24 February 2013 . Retrieved 1 October 2006 . ^ Roopnarine PD (March 2014). "Humans are apex predators" . Proceedings of the National Academy of Sciences of the United States of America . 111 (9): E796. Bibcode : 2014PNAS..111E.796R . doi : 10.1073/pnas.1323645111 . PMC 3948303 . PMID 24497513 . ^ Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature" . Science . AAAS . Archived from the original on 26 October 2021 . Retrieved 9 May 2021 . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use – principally agriculture – that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.) ^ Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions" . Proceedings of the National Academy of Sciences of the United States of America . 103 (29): 10941–10946. Bibcode : 2006PNAS..10310941P . doi : 10.1073/pnas.0604181103 . PMC 1544153 . PMID 16829570 . ^ Collins D (1976). The Human Revolution: From Ape to Artist . Phaidon. p. 208 . ISBN 978-0-7148-1676-0 . ^ Weisberger, Mindy (March 23, 2024). "Why don't humans have tails? Scientists find answers in an unlikely place" . CNN . Archived from the original on March 24, 2024 . Retrieved March 24, 2024 . ^ Marks JM (2001). Human Biodiversity: Genes, Race, and History . Transaction Publishers. p. 16. ISBN 978-0-202-36656-2 . ^ Gea, J (2008). "The Evolution of the Human Species: A Long Journey for the Respiratory System". Archivos de Bronconeumología ((English Edition)) . 44 (5): 263–270. doi : 10.1016/S1579-2129(08)60042-7 . ^ O'Neil D. "Humans" . Primates . Palomar College. Archived from the original on 11 January 2013 . Retrieved 6 January 2013 . ^ "How to be Human: The reason we are so scarily hairy" . New Scientist . 2017. Archived from the original on 25 February 2021 . Retrieved 29 April 2020 . ^ Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . ^ Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White" . Evolution: Library . PBS. Archived from the original on 16 February 2013 . Retrieved 6 January 2013 . ^ Roser M, Appel C, Ritchie H (8 October 2013). "Human Height" . Our World in Data . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ "Senior Citizens Do Shrink – Just One of the Body Changes of Aging" . News . Senior Journal. Archived from the original on 19 February 2013 . Retrieved 6 January 2013 . ^ Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology . 136 (1): 71–84. doi : 10.1016/S1095-6433(02)00294-5 . PMID 14527631 . ^ "Human weight" . Articleworld.org. Archived from the original on 8 December 2011 . Retrieved 10 December 2011 . ^ Schlessingerman A (2003). "Mass Of An Adult" . The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018 . Retrieved 31 December 2017 . ^ Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology) . Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1 . Retrieved 5 April 2009 . ^ Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care" . British Journal of Anaesthesia . 85 (1): 91–108. doi : 10.1093/bja/85.1.91 . PMID 10927998 . ^ Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology . 93 (1): 1–16. doi : 10.1086/696721 . ISSN 0033-5770 . S2CID 90757192 . ^ Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance" . The New York Times . Archived from the original on 5 November 2015. ^ John B. "What is the role of sweating glands in balancing body temperature when running a marathon?" . Livestrong.com. Archived from the original on 31 January 2013 . Retrieved 6 January 2013 . ^ Shave, R. E.; Lieberman, D. E.; Drane, A. L.; et al. (2019). "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart" . PNAS . 116 (40): 19905–19910. Bibcode : 2019PNAS..11619905S . doi : 10.1073/pnas.1906902116 . PMC 6778238 . PMID 31527253 . ^ Ríos, L; Sleeper, M. M.; Danforth, M. D.; et al. (2023). "The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution" . Scientific Reports . 13 (6841): 6841. Bibcode : 2023NatSR..13.6841R . doi : 10.1038/s41598-023-33675-1 . hdl : 10261/309357 . PMC 10133235 . PMID 37100851 . ^ Therman E (1980). Human Chromosomes: Structure, Behavior, Effects . Springer US . pp. 112–124. doi : 10.1007/978-1-4684-0107-3 . ISBN 978-1-4684-0109-7 . S2CID 36686283 . ^ Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex" . Journal of Medical Genetics . 3 (2): 117–123. doi : 10.1136/jmg.3.2.117 . PMC 1012913 . PMID 6007033 . ^ Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics . 61 (3): 216–228. doi : 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S . PMID 8741866 . ^ Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics . 53 (1): 27–34. doi : 10.1038/s41588-020-00755-1 . PMID 33414551 . S2CID 230986741 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . Between any two humans, the amount of genetic variation – biochemical individuality – is about 0.1%. ^ Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human" . PLOS Biology . 5 (10): e254. doi : 10.1371/journal.pbio.0050254 . PMC 1964779 . PMID 17803354 . ^ Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research" . American Journal of Human Genetics . 77 (4): 519–532. doi : 10.1086/491747 . PMC 1275602 . PMID 16175499 . ^ "Chimps show much greater genetic diversity than humans" . Media . University of Oxford. Archived from the original on 18 December 2013 . Retrieved 13 December 2013 . ^ Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography" . Proceedings of the National Academy of Sciences of the United States of America . 95 (4): 1961–1967. Bibcode : 1998PNAS...95.1961H . doi : 10.1073/pnas.95.4.1961 . PMC 19224 . PMID 9465125 . ^ Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans" . Proceedings of the National Academy of Sciences of the United States of America . 94 (7): 3100–3103. Bibcode : 1997PNAS...94.3100J . doi : 10.1073/pnas.94.7.3100 . PMC 20328 . PMID 9096352 . ^ Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story" . The New York Times . Archived from the original on 14 January 2012 . Retrieved 13 February 2012 . ^ Pennisi E (February 2001). "The human genome". Science . 291 (5507): 1177–1180. doi : 10.1126/science.291.5507.1177 . PMID 11233420 . S2CID 38355565 . ^ Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature . 590 (7845): 220–221. Bibcode : 2021Natur.590..220R . doi : 10.1038/d41586-021-00237-2 . PMID 33568827 . S2CID 231882262 . ^ Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations" . Nature . 467 (7311): 52–58. Bibcode : 2010Natur.467...52T . doi : 10.1038/nature09298 . PMC 3173859 . PMID 20811451 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private , common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture. ^ Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes" . Genome Biology . 11 (5): 206. doi : 10.1186/gb-2010-11-5-206 . PMC 2898077 . PMID 20441615 . ^ Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature . 325 (6099): 31–36. Bibcode : 1987Natur.325...31C . doi : 10.1038/325031a0 . PMID 3025745 . S2CID 4285418 . ^ Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock" . American Journal of Human Genetics . 84 (6): 740–759. doi : 10.1016/j.ajhg.2009.05.001 . PMC 2694979 . PMID 19500773 . ^ "University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history" . 20 August 2017. Archived from the original on 20 August 2017. ^ Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females" . Science . 341 (6145): 562–565. Bibcode : 2013Sci...341..562P . doi : 10.1126/science.1237619 . PMC 4032117 . PMID 23908239 . ^ Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set . John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1 . ^ Jukic AM, Baird DD, Weinberg CR , McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation" . Human Reproduction . 28 (10): 2848–2855. doi : 10.1093/humrep/det297 . PMC 3777570 . PMID 23922246 . ^ Klossner NJ (2005). Introductory Maternity Nursing . Lippincott Williams & Wilkins. p. 103. ISBN 978-0-7817-6237-3 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . The fetal stage is from the beginning of the 9th week after fertilization and continues until birth ^ World Health Organization (November 2014). "Preterm birth Fact sheet N°363" . who.int . Archived from the original on 7 March 2015 . Retrieved 6 March 2015 . ^ Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application" . American Journal of Obstetrics and Gynecology . 218 (2S): S619–S629. doi : 10.1016/j.ajog.2017.12.010 . PMID 29422204 . S2CID 46810955 . ^ "What is the average baby length? Growth chart by month" . www.medicalnewstoday.com . 18 March 2019. Archived from the original on 27 January 2021 . Retrieved 18 April 2021 . ^ Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal . 5 (2): 113–122. PMID 15024783 . ^ Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology . 35 (S15): 89–124. doi : 10.1002/ajpa.1330350605 . ISSN 1096-8644 . ^ Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma" . American Journal of Obstetrics and Gynecology . 222 (1): 3–16. doi : 10.1016/j.ajog.2019.06.043 . PMC 9069416 . PMID 31251927 . S2CID 195761874 . ^ Barras C (22 December 2016). "The real reasons why childbirth is so painful and dangerous". BBC. ^ Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?" . Newsweek . Archived from the original on 28 June 2007. A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa , compared to 1 in 2,800 in developed countries . ^ Rush D (July 2000). "Nutrition and maternal mortality in the developing world" . The American Journal of Clinical Nutrition . 72 (1 Suppl): 212S–240S. doi : 10.1093/ajcn/72.1.212S . PMID 10871588 . ^ Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour . Oxford University Press. p. 7. ISBN 978-0-19-958696-7 . Retrieved 30 July 2022 . ^ Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning . p. 296. ISBN 978-0-495-60037-4 . Archived from the original on 3 October 2023 . Retrieved 30 July 2022 . ^ Schuiling KD, Likis FE (2016). Women's Gynecologic Health . Jones & Bartlett Learning . p. 22. ISBN 978-1-284-12501-6 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13. ^ Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy . SAGE Publications . pp. 18–19. ISBN 978-1-4833-6475-9 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average). ^ Mintz S (1993). "Life stages". Encyclopedia of American Social History . 3 : 7–33. ^ Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?" . Indian Journal of Endocrinology and Metabolism . 18 (Suppl 1): S53-62. doi : 10.4103/2230-8210.145075 . PMC 4266869 . PMID 25538878 . ^ Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?" . Biology of Reproduction . 79 (3): 398–406. doi : 10.1095/biolreprod.108.068536 . PMC 2553520 . PMID 18495681 . ^ Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality . New York: Basic Books. pp. 167–170. ISBN 978-0-465-03127-6 . ^ Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology . 10 (2): 43–57. doi : 10.1002/evan.1013 . S2CID 1665503 . ^ Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth" . USC Trojan Family Magazine . Archived from the original on 13 December 2010 . Retrieved 7 December 2010 . ^ Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex" . Society of Actuaries. Archived from the original on 1 July 2013. ^ "Life expectancy at birth, female (years)" . World Bank . 2018. Archived from the original on 24 January 2021 . Retrieved 13 October 2020 . ^ "Life expectancy at birth, male (years)" . World Bank . 2018. Archived from the original on 24 February 2021 . Retrieved 13 October 2020 . ^ Conceição P, et al. (2019). Human Development Report (PDF) . United Nations Development Programme. ISBN 978-92-1-126439-5 . Archived (PDF) from the original on 20 March 2021 . Retrieved 30 July 2022 . ^ "Human Development Report 2019" (PDF) . United Nations Development Programme . Archived from the original (PDF) on 22 April 2022 . Retrieved 30 July 2022 . ^ "The World Factbook" . U.S. Central Intelligence Agency. Archived from the original on 12 September 2009 . Retrieved 2 April 2005 . ^ "Chapter 1: Setting the Scene" (PDF) . UNFPA. 2012. Archived from the original (PDF) on 12 June 2013 . Retrieved 11 January 2013 . ^ Haenel H (1989). "Phylogenesis and nutrition". Die Nahrung . 33 (9): 867–887. PMID 2697806 . ^ Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable . pp. 264–265. Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods. ^ American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association . 103 (6): 748–765. doi : 10.1053/jada.2003.50142 . PMID 12778049 . ^ Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet" . American Journal of Physical Anthropology . 162 (S63): 84–109. doi : 10.1002/ajpa.23148 . PMID 28105723 . ^ Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century" . The American Journal of Clinical Nutrition . 81 (2): 341–354. doi : 10.1093/ajcn.81.2.341 . PMID 15699220 . ^ Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context" . The Proceedings of the Nutrition Society . 61 (4): 517–526. doi : 10.1079/PNS2002180 . PMID 12691181 . ^ John Carey (2023). "Unearthing the origins of agriculture" . Proceedings of the National Academy of Sciences . 120 (15): e2304407120. Bibcode : 2023PNAS..12004407C . doi : 10.1073/pnas.2304407120 . PMC 10104519 . PMID 37018195 . ^ Ayelet Shavit; Gonen Sharon (2023). "Can models of evolutionary transition clarify the debates over the Neolithic Revolution?" . Philosophical Transactions of the Royal Society B . 378 (1872). doi : 10.1098/rstb.2021.0413 . PMC 9869441 . PMID 36688395 . } ^ Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences" . The American Journal of Clinical Nutrition . 90 (3): 707S–711S. doi : 10.3945/ajcn.2009.27462B . PMID 19656837 . ^ Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology . 69 (5): 605–628. PMID 9299882 . ^ Gibbons A. "The Evolution of Diet" . National Geographic . Archived from the original on 18 August 2014 . Retrieved 18 April 2021 . ^ Ritchie H, Roser M (20 August 2017). "Diet Compositions" . Our World in Data . Archived from the original on 25 August 2021 . Retrieved 30 July 2022 . ^ Lieberson AD (2004). "How Long Can a Person Survive without Food?" . Scientific American . Archived from the original on 14 February 2019 . Retrieved 18 April 2021 . ^ Spector D (9 March 2018). "Here's how many days a person can survive without water" . Business Insider Australia . Archived from the original on 26 June 2014 . Retrieved 18 April 2021 . ^ Holmes J. "Losing 25,000 to Hunger Every Day" . United Nations . Archived from the original on 27 May 2020 . Retrieved 18 April 2021 . ^ Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic" . NPR . Archived from the original on 28 June 2021 . Retrieved 18 April 2021 . ^ Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet . 349 (9063): 1436–1442. doi : 10.1016/S0140-6736(96)07495-8 . PMID 9164317 . S2CID 2569153 . ^ Haslam DW, James WP (October 2005). "Obesity". Lancet . 366 (9492): 1197–1209. doi : 10.1016/S0140-6736(05)67483-1 . PMID 16198769 . S2CID 208791491 . ^ Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine . 30 (3): 415–444, vii. doi : 10.1016/j.ccm.2009.05.001 . PMID 19700042 . ^ de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology . 2 (1): 45–55. doi : 10.1016/j.ehb.2003.11.001 . PMID 15463992 . ^ O'Neil D. "Adapting to Climate Extremes" . Human Biological Adaptability . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status" . PLOS Genetics . 13 (9): e1006977. doi : 10.1371/journal.pgen.1006977 . PMC 5600404 . PMID 28873402 . ^ Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics . 35 (4): 311–313. doi : 10.1038/ng1263 . PMID 14634648 . S2CID 20415396 . ^ Hedrick PW (October 2011). "Population genetics of malaria resistance in humans" . Heredity . 107 (4): 283–304. doi : 10.1038/hdy.2011.16 . PMC 3182497 . PMID 21427751 . ^ Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria" . British Journal of Haematology . 141 (3): 276–286. doi : 10.1111/j.1365-2141.2008.07085.x . PMID 18410566 . S2CID 28191911 . ^ Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea" . Frontiers in Ecology and Evolution . 5 . doi : 10.3389/fevo.2017.00025 . hdl : 11858/00-001M-0000-002C-DD87-4 . ISSN 2296-701X . S2CID 34882477 . ^ Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads" . Cell . 173 (3): 569–580.e15. doi : 10.1016/j.cell.2018.03.054 . PMID 29677510 . ^ Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology . 45 (1): 105–08. doi : 10.1086/381006 . S2CID 224795768 . ^ Roberts D (2011). Fatal Invention . London & New York: The New Press. ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation" . Proceedings of the National Academy of Sciences of the United States of America . 107 (Supplement_2): 8962–8968. Bibcode : 2010PNAS..107.8962J . doi : 10.1073/pnas.0914628107 . PMC 3024016 . PMID 20445093 . ^ Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF) . Journal of Human Evolution . 39 (1): 57–106. doi : 10.1006/jhev.2000.0403 . PMID 10896812 . Archived from the original (PDF) on 14 January 2012. ^ Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R" . American Journal of Human Genetics . 66 (4): 1351–1361. doi : 10.1086/302863 . PMC 1288200 . PMID 10733465 . ^ Robin A (1991). Biological Perspectives on Human Pigmentation . Cambridge: Cambridge University Press. ^ "The Science Behind the Human Genome Project" . Human Genome Project . US Department of Energy. Archived from the original on 2 January 2013 . Retrieved 6 January 2013 . Almost all (99.9%) nucleotide bases are exactly the same in all people. ^ O'Neil D. "Ethnicity and Race: Overview" . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation" . Nature Genetics . 36 (11 Suppl): S17-20. doi : 10.1038/ng1455 . PMID 15507998 . ^ O'Neil D. "Models of Classification" . Modern Human Variation . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Palmié S (May 2007). "Genomics, divination, 'racecraft' ". American Ethnologist . 34 (2): 205–222. doi : 10.1525/ae.2007.34.2.205 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations. ^ Goodman A. "Interview with Alan Goodman" . Race Power of and Illusion . PBS. Archived from the original on 29 October 2012 . Retrieved 6 January 2013 . ^ Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF) . New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012 . Retrieved 5 September 2013 . ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo ^ O'Neil D. "Overview" . Modern Human Variation . Palomar College. Archived from the original on 5 November 2012 . Retrieved 6 January 2013 . ^ Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" . American Journal of Human Genetics . 66 (3): 979–988. doi : 10.1086/302825 . PMC 1288178 . PMID 10712212 . ^ "New Research Proves Single Origin Of Humans In Africa" . Science Daily . 19 July 2007. Archived from the original on 4 November 2011 . Retrieved 5 September 2011 . ^ Manica A, Amos W, Balloux F , Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation" . Nature . 448 (7151): 346–348. Bibcode : 2007Natur.448..346M . doi : 10.1038/nature05951 . PMC 1978547 . PMID 17637668 . ^ Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals" . Cell . 180 (4): 677–687.e16. doi : 10.1016/j.cell.2020.01.012 . PMID 32004458 . S2CID 210955842 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations. ^ Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations" . Science Advances . 6 (7): eaax5097. Bibcode : 2020SciA....6.5097D . doi : 10.1126/sciadv.aax5097 . PMC 7015685 . PMID 32095519 . Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. ^ Pierce BA (2012). Genetics: A Conceptual Approach . Macmillan. p. 75. ISBN 978-1-4292-3252-4 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology . Cambridge University Press. p. 74. ISBN 978-0-521-87948-4 . Retrieved 30 July 2022 . ^ Fusco G, Minelli A (10 October 2019). The Biology of Reproduction . Cambridge University Press. p. 304. ISBN 978-1-108-49985-9 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution . 47 (4): 253–266. doi : 10.1016/j.jhevol.2004.07.004 . PMID 15454336 . ^ Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960–2002" (PDF) . Advance Data (347): 1–17. PMID 15544194 . Archived from the original (PDF) on 23 February 2011. ^ Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology . 66 (3): 254–262. doi : 10.1007/BF00235103 . hdl : 11375/22586 . PMID 8477683 . S2CID 206772211 . ^ Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity . Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi : 10.1007/978-3-319-70178-3_2 . ISBN 978-3-319-70177-6 . PMID 29224088 . ^ Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know" . International Journal of Women's Dermatology . 4 (3): 122–130. doi : 10.1016/j.ijwd.2018.03.002 . PMC 6116811 . PMID 30175213 . ^ Easter C. "Sex Linked" . National Human Genome Research Institute . Archived from the original on 14 April 2022 . Retrieved 18 April 2021 . ^ Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior . 27 (4): 283–296. doi : 10.1016/j.evolhumbehav.2005.11.003 . S2CID 32562654 . ^ "Gender, women, and health" . Reports from WHO 2002–2005 . Archived from the original on 25 June 2013. ^ Sax, Leonard (1 August 2002). "How common is lntersex? A response to Anne Fausto-Sterling" . The Journal of Sex Research . 39 (3): 174–178. doi : 10.1080/00224490209552139 . ISSN 0022-4499 . PMID 12476264 . S2CID 33795209 . ^ "3-D Brain Anatomy" . The Secret Life of the Brain . Public Broadcasting Service. Archived from the original on 5 September 2017 . Retrieved 3 April 2005 . ^ Stern P (22 June 2018). "The human prefrontal cortex is special" . Science . 360 (6395): 1311–1312. Bibcode : 2018Sci...360S1311S . doi : 10.1126/science.360.6395.1311-g . ISSN 0036-8075 . S2CID 149581944 . ^ Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?" . Journal of Intelligence . 2 (3): 119–121. doi : 10.3390/jintelligence2030119 . ISSN 2079-3200 . ^ "Humans not smarter than animals, just different, experts say" . phys.org . Archived from the original on 30 January 2021 . Retrieved 24 October 2020 . ^ Robson D. "We've got human intelligence all wrong" . www.bbc.com . Archived from the original on 31 January 2021 . Retrieved 24 October 2020 . ^ Owen J (26 February 2015). "Many Animals – Including Your Dog – May Have Horrible Short-Term Memories" . National Geographic News . Archived from the original on 19 April 2021 . Retrieved 6 September 2020 . ^ Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research" . American Journal of Physical Anthropology . 116 (S33): 3–24. doi : 10.1002/ajpa.20001 . PMC 2238342 . PMID 11786989 . ^ Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?" . ABC News (American) . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self" . New Scientist . Archived from the original on 18 February 2021 . Retrieved 22 April 2020 . ^ Beck J (2019). "Can We Really Know What Animals Are Thinking?" . Snopes . Archived from the original on 31 October 2021 . Retrieved 22 April 2020 . ^ Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies" . Sleep Medicine Reviews . 14 (4): 239–247. doi : 10.1016/j.smrv.2009.08.001 . PMC 2888649 . PMID 19896872 . ^ Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep" " . Science.howstuffworks.com. Archived from the original on 15 May 2012 . Retrieved 11 August 2012 . ^ Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience . 10 (11): 803–813. doi : 10.1038/nrn2716 . PMID 19794431 . S2CID 205505278 . ^ Empson J (2002). Sleep and dreaming (3rd ed.). New York: Palgrave/St. Martin's Press. ^ Lite J (29 July 2010). "How Can You Control Your Dreams?" . Scientific America . Archived from the original on 2 February 2015. ^ Domhoff W (2002). The scientific study of dreams . APA Press. ^ "Consciousness" . Merriam-Webster . Archived from the original on 7 September 2019 . Retrieved 4 June 2012 . ^ van Gulick R (2004). "Consciousness" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019 . Retrieved 30 July 2022 . ^ Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness . Wiley. ISBN 978-0-470-75145-9 . ^ Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy . Oxford University Press. ISBN 978-0-19-926479-7 . ^ Block N (June 1995). "On a confusion about a function of consciousness" . Behavioral and Brain Sciences . 18 (2): 227–247. doi : 10.1017/S0140525X00038474 . S2CID 246244859 . ^ Jaynes J (2000) [1976]. The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF) . Houghton Mifflin. ISBN 0-618-05707-2 . Archived from the original (PDF) on 7 August 2019 . Retrieved 25 October 2020 . ^ Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition . 12 (4): 717–731. doi : 10.1016/s1053-8100(03)00081-3 . PMID 14656513 . S2CID 10241157 . ^ Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness" . Stanford Encyclopedia of Philosophy . Archived from the original on 13 April 2021 . Retrieved 31 August 2014 . ^ Antony MV (2001). "Is consciousness ambiguous?". Journal of Consciousness Studies . 8 : 19–44. ^ "Cognition" . Lexico . Oxford University Press and Dictionary.com . Archived from the original on 8 July 2016 . Retrieved 6 May 2020 . ^ Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality . The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi : 10.1007/978-3-030-03633-1_14 . ISBN 978-3-030-03633-1 . S2CID 189379814 . ^ "American Psychological Association (2013). Glossary of psychological terms" . Apa.org. Archived from the original on 8 July 2014 . Retrieved 13 August 2014 . ^ "Developmental Psychology Studies Human Development Across the Lifespan" . www.apa.org . Archived from the original on 9 July 2014 . Retrieved 28 August 2017 . ^ Burman E (2017). Deconstructing Developmental Psychology . New York: Routledge. ISBN 978-1-138-84695-1 . ^ Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology : 307–314. doi : 10.1016/B0-12-657410-3/00510-9 . ISBN 978-0-12-657410-4 . ^ McLeod S (20 March 2020). "Maslow's Hierarchy of Needs" . Simplypsychology.org . Simply Scholar Limited. Archived from the original on 8 November 2018 . Retrieved 4 April 2020 . Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up. ^ Heckhausen J, Heckhausen H (28 March 2018). "Motivation and Action: Introduction and Overview". Motivation and Action . Introduction and Overview: Springer, Cham. p. 1. doi : 10.1007/978-3-319-65094-4_1 . ISBN 978-3-319-65093-7 . ^ Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews . 26 (2–3): 83–86. doi : 10.1016/s0165-0173(97)00064-7 . PMID 9651488 . S2CID 8504450 . ^ Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions . New York: Oxford University Press. pp. 291–293. ISBN 978-0-19-508944-8 . Emotional processing, but not emotions, can occur unconsciously. ^ Cabanac M (2002). "What is emotion?". Behavioural Processes . 60 (2): 69–83. doi : 10.1016/S0376-6357(02)00078-5 . PMID 12426062 . S2CID 24365776 . Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure) ^ Scirst DL (2011). Psychology Second Edition . New York: Worth Publishers. p. 310 . ISBN 978-1-4292-3719-2 . ^ Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality . 67 (2): 331–371. doi : 10.1111/1467-6494.00058 . PMID 10202807 . ^ Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory" . Frontiers in Psychology . 8 : 1454. doi : 10.3389/fpsyg.2017.01454 . PMC 5573739 . PMID 28883804 . ^ Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology . Oxford University Press. Archived from the original on 29 January 2021 . Retrieved 30 July 2022 . ^ Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals" . Industrial Psychiatry Journal . 24 (1): 54–58. doi : 10.4103/0972-6748.160934 . PMC 4525433 . PMID 26257484 . ^ Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions" . The American Psychologist . 56 (3): 218–226. doi : 10.1037/0003-066X.56.3.218 . PMC 3122271 . PMID 11315248 . ^ Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica . 90 (3): 387–411. doi : 10.11612/resphil.2013.90.3.5 . ^ Haybron DM (13 April 2014). "Happiness and Its Discontents" . The Opinion Pages . The New York Times. Archived from the original on 12 October 2018 . Retrieved 30 July 2022 . I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life. ^ Graham MC (2014). Facts of Life: ten issues of contentment . Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5 . ^ "Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy" . ScienceDaily . American Psychological Association . 14 August 2017. Archived from the original on 11 November 2020 . Retrieved 25 October 2020 . ^ Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality . Jones & Bartlett Publishers . pp. 4–10. ISBN 978-1-284-08154-1 . Retrieved 21 June 2017 . Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings. ^ Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives . Taylor & Francis . pp. 32–42. ISBN 978-0-7890-2671-2 . ^ Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology . 3 (4): 85–89. doi : 10.1097/01.XHA.0000432482.01760.b0 . S2CID 147235090 . ^ "Sexual orientation, homosexuality and bisexuality" . American Psychological Association . Archived from the original on 8 August 2013 . Retrieved 10 August 2013 . ^ Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science" . Psychological Science in the Public Interest . 17 (2): 45–101. doi : 10.1177/1529100616637616 . PMID 27113562 . ^ LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation . Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6 . Retrieved 30 July 2022 . ^ Balthazart J (2012). The Biology of Homosexuality . Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0 . Retrieved 30 July 2022 . ^ Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York: Basic Books. ISBN 978-0-465-00802-5 . ^ Fromm E (2000). The art of loving . New York: Harper Perennial. ISBN 978-0-06-095828-2 . ^ "Love, Actually: The science behind lust, attraction, and companionship" . Science in the News . 14 February 2017. Archived from the original on 28 October 2020 . Retrieved 25 October 2020 . ^ "What are the top 200 most spoken languages?" . Ethnologue: Languages of the World . 2020. Archived from the original on 12 January 2013 . Retrieved 30 July 2022 . ^ World . The World Factbook (Report). Central Intelligence Agency . Archived from the original on 26 January 2021 . Retrieved 15 November 2021 . ^ "The Changing Global Religious Landscape" . Pew Research Center. 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 30 July 2022 . ^ Ord T (2020). The Precipice: Existential Risk and the Future of Humanity . New York: Hachette Books. ISBN 978-0-316-48489-3 . Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence... ^ Goldman JG (2012). "Pay attention… time for lessons at animal school" . bbc.com . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding" . Science Advances . 4 (11): eaar8334. Bibcode : 2018SciA....4.8334W . doi : 10.1126/sciadv.aar8334 . PMC 6248967 . PMID 30474053 . ^ Johnson-Frey SH (July 2003). "What's so special about human tool use?" . Neuron . 39 (2): 201–204. doi : 10.1016/S0896-6273(03)00424-0 . PMID 12873378 . S2CID 18437970 . ^ Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology . 19 (1): 27–33. doi : 10.1016/j.conb.2009.02.003 . PMID 19328675 . S2CID 18277620 . In short, the evidence to date that animals have an understanding of folk physics is at best mixed. ^ Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To" . National Geographic News . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education" . Procedia - Social and Behavioral Sciences . The Proceedings of 6th World Conference on educational Sciences. 191 : 2565–2567. doi : 10.1016/j.sbspro.2015.04.690 . ISSN 1877-0428 . ^ McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species" . The Guardian . Archived from the original on 5 February 2021 . Retrieved 22 April 2020 . ^ Nicholls H (29 June 2015). "Babblers speak to the origin of language" . The Guardian . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Dasgupta S (2015). "Can any animals talk and use language like humans?" . bbc.com . Archived from the original on 2 May 2020 . Retrieved 22 April 2020 . Most animals are not vocal learners. ^ Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?" . Royal Society. Archived from the original on 18 January 2021 . Retrieved 24 October 2020 . ^ Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?" . BMC Biology . 15 (1): 64. doi : 10.1186/s12915-017-0405-3 . PMC 5525259 . PMID 28738867 . ^ Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist . 208 (2789): ii–iii. Bibcode : 2010NewSc.208D...2F . doi : 10.1016/S0262-4079(10)62961-2 . ISSN 0262-4079 . ^ Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments . London: Palgrave Macmillan UK. pp. 229–255. doi : 10.1057/978-1-137-58746-6_7 . ISBN 978-1-137-58746-6 . ^ "Culture | United Nations For Indigenous Peoples" . www.un.org . 5 June 2015. Archived from the original on 26 November 2020 . Retrieved 24 October 2020 . ^ Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World . New York: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1 . ^ Mavrody S (2013). Visual Art Forms: Traditional to Digital . Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9 . Retrieved 30 July 2022 . ^ "Types of Literary Arts and Their Understanding – bookfestivalscotland.com" . Bookfestival Scotland . 2020. Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ "Bachelor of Performing Arts" (PDF) . University of Otago . Archived (PDF) from the original on 14 December 2021 . Retrieved 30 July 2022 . ^ Brown S (24 October 2018). "Toward a Unification of the Arts" . Frontiers in Psychology . 9 : 1938. doi : 10.3389/fpsyg.2018.01938 . ISSN 1664-1078 . PMC 6207603 . PMID 30405470 . ^ "Culinary arts – How cooking can be an art" . Northern Contemporary Art . 21 October 2019. Archived from the original on 11 May 2021 . Retrieved 5 May 2021 . ^ Smuts A (1 January 2005). "Are Video Games Art?" . Contemporary Aesthetics (Journal Archive) . 3 (1). Archived from the original on 29 May 2022 . Retrieved 30 July 2022 . ^ Cameron IA, Pimlott N (September 2015). "Art of medicine" . Canadian Family Physician . 61 (9): 739–740. PMC 4569099 . PMID 26371092 . ^ Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy . 25 (4): 458–470. doi : 10.1080/10286632.2017.1311328 . ISSN 1028-6632 . S2CID 151443044 . ^ Morriss-Kay GM (February 2010). "The evolution of human artistic creativity" . Journal of Anatomy . 216 (2): 158–176. doi : 10.1111/j.1469-7580.2009.01160.x . PMC 2815939 . PMID 19900185 . ^ Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature . 518 (7538): 228–231. Bibcode : 2015Natur.518..228J . doi : 10.1038/nature13962 . PMID 25470048 . S2CID 4461751 . ^ St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave" . The New York Times . Archived from the original on 14 April 2020 . Retrieved 20 September 2018 . ^ Radford T (16 April 2004). "World's oldest jewellery found in cave" . The Guardian . ISSN 0261-3077 . Archived from the original on 12 February 2021 . Retrieved 23 September 2020 . ^ Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches . Amsterdam: Valiz. pp. 241–263. ^ Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia . 92 (92): 147–177. doi : 10.4436/JASS.92008 (inactive 2024-03-20). PMID 25020016 . {{ cite journal }} : CS1 maint: DOI inactive as of March 2024 ( link ) ^ Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness" (PDF) . NeuroImage . 103 : 55–64. doi : 10.1016/j.neuroimage.2014.09.009 . PMID 25224999 . S2CID 4727529 . ^ Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences . 1337 (1): 140–146. Bibcode : 2015NYASA1337..140K . doi : 10.1111/nyas.12632 . PMID 25773628 . S2CID 206224849 . ^ Chow D (22 March 2010). "Why Do Humans Dance?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 21 September 2020 . ^ Krakauer J (26 September 2008). "Why do we like to dance – And move to the beat?" . Scientific American . Archived from the original on 28 February 2021 . Retrieved 21 September 2020 . ^ Prior KS (21 June 2013). "How Reading Makes Us More Human" . The Atlantic . Archived from the original on 29 January 2021 . Retrieved 23 September 2020 . ^ Puchner M. "How stories have shaped the world" . www.bbc.com . Archived from the original on 5 January 2021 . Retrieved 23 September 2020 . ^ Dalley, Stephanie , ed. (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5 . ^ Hernadi P (2001). "Literature and Evolution" . SubStance . 30 (1/2): 55–71. doi : 10.2307/3685504 . ISSN 0049-2426 . JSTOR 3685504 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run" . The Guardian (U.S. ed.). New York. Archived from the original on 18 June 2022 . Retrieved 30 July 2022 . ^ Clark JD; de Heinzelin J ; Schick KD ; Hart WK; White TD ; WoldeGabriel G; Walter RC; Suwa G ; Asfaw B ; Vrba E ; H.-Selassie Y (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science . 264 (5167): 1907–1910. Bibcode : 1994Sci...264.1907C . doi : 10.1126/science.8009220 . PMID 8009220 . ^ Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use" . livescience.com . Archived from the original on 4 October 2020 . Retrieved 9 October 2020 . ^ Orban GA, Caruana F (2014). "The neural basis of human tool use" . Frontiers in Psychology . 5 : 310. doi : 10.3389/fpsyg.2014.00310 . PMC 3988392 . PMID 24782809 . ^ Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa" . Proceedings of the National Academy of Sciences of the United States of America . 109 (20): E1215-20. doi : 10.1073/pnas.1117620109 . PMC 3356665 . PMID 22474385 . ^ Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1696): 20150164. doi : 10.1098/rstb.2015.0164 . PMC 4874402 . PMID 27216521 . ^ Damiano J (2018). "Neolithic Era Tools: Inventing a New Age" . MagellanTV . Archived from the original on 5 January 2021 . Retrieved 9 October 2020 . ^ Deng Y, Wang P (2011). Ancient Chinese inventions . Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6 . OCLC 671710733 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Schifman J (9 July 2018). "The Entire History of Steel" . Popular Mechanics . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Wilkinson, Freddie (9 January 2020). "Industrial Revolution and Technology" . National Geographic Society . Archived from the original on 30 September 2020 . Retrieved 9 October 2020 . ^ Roser, Max ; Ritchie, Hannah (11 May 2013). "Technological Progress" . Our World in Data . Archived from the original on 10 September 2021 . Retrieved 30 July 2022 . ^ Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel" . The Atlantic . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Idinopulos TA (1998). "What Is Religion?" . CrossCurrents . 48 (3): 366–380. ISSN 0011-1953 . JSTOR 24460821 . Archived from the original on 13 October 2020 . Retrieved 30 July 2022 . ^ Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology . 54 (1): 377–402. doi : 10.1146/annurev.psych.54.101601.145024 . PMID 12171998 . ^ King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?" . The Atlantic . Archived from the original on 20 January 2021 . Retrieved 8 October 2020 . ^ Ball P (2015). "Complex societies evolved without belief in all-powerful deity" . Nature News . doi : 10.1038/nature.2015.17040 . S2CID 183474917 . Archived from the original on 16 May 2021 . Retrieved 30 July 2022 . ^ Culotta E (November 2009). "Origins. On the origin of religion". Science . 326 (5954): 784–787. Bibcode : 2009Sci...326..784C . doi : 10.1126/science.326_784 . PMID 19892955 . ^ Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation" . Evolution and Human Behavior . 32 (1): 41–49. doi : 10.1016/j.evolhumbehav.2010.07.008 . ISSN 1090-5138 . Archived from the original on 15 October 2020 . Retrieved 30 July 2022 . ^ Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA – Journal of Death and Dying . 41 (1): 5–22. doi : 10.2190/Q21C-5VED-GYW6-W091 . ISSN 0030-2228 . S2CID 145686249 . ^ McKay R, Whitehouse H (March 2015). "Religion and morality" . Psychological Bulletin . 141 (2): 447–473. doi : 10.1037/a0038455 . PMC 4345965 . PMID 25528346 . ^ Bernhard Nitsche; Marcus Schmücker, eds. (2023). God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality . De Gruyter . doi : 10.1515/9783110698343 . ISBN 978-3-11-069834-3 . ^ Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique" . Journal of Religion and Health (Submitted manuscript). 47 (2): 134–163. doi : 10.1007/s10943-008-9165-2 . PMC 8823950 . PMID 19105008 . S2CID 25349208 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular" . The Guardian . ISSN 0261-3077 . Archived from the original on 1 March 2021 . Retrieved 8 October 2020 . ^ Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe" . Pew Research Center . Archived from the original on 24 November 2019 . Retrieved 8 October 2020 . ^ "The Changing Global Religious Landscape" . Pew Research Center's Religion & Public Life Project . 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 8 October 2020 . ^ Di Christina, Mariette (September 2018). "A Very Human Story: Why Our Species Is Special" . Scientific American . Archived from the original on 24 November 2020 . Retrieved 27 September 2020 . ^ Andersen H , Hepburn B (2020). "Scientific Method" . In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Lo Presti R (2014). "History of science: The first scientist" . Nature . 512 (7514): 250–251. Bibcode : 2014Natur.512..250L . doi : 10.1038/512250a . ISSN 1476-4687 . S2CID 4394696 . ^ Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn . Springer. p. 1. ISBN 978-3-642-18904-3 . OCLC 883392276 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Needham, J ; Wang Ling (1954). Science and civilisation in China . Cambridge University Press. p. 111. ISBN 0-521-05799-X . OCLC 779676 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6 . OCLC 615209781 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017 . Retrieved 3 July 2017 . ^ Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition . Cambridge University Press. pp. 209–210. ISBN 978-1-107-01116-8 . ^ "Branches of Science" (PDF) . University of Chicago . Archived from the original (PDF) on 23 April 2017 . Retrieved 26 June 2017 . ^ "What is Philosophy?" . Department of Philosophy . Florida State University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ "Philosophy" . Definition, Systems, Fields, Schools, & Biographies . Encyclopedia Britannica. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day" . Philosophy and Phenomenological Research . 7 (3): 461. doi : 10.2307/2102800 . JSTOR 2102800 . Archived from the original on 31 March 2022 . Retrieved 30 July 2022 . ^ Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?" . ieet.org . Archived from the original on 4 March 2021 . Retrieved 8 August 2020 . ^ Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?" . European Journal of Information Systems . 27 (3): 263–277. doi : 10.1080/0960085X.2018.1470776 . hdl : 2086/16128 . ISSN 0960-085X . S2CID 64796132 . ^ Schizzerotto A. "Social Stratification" (PDF) . University of Trento . Archived from the original (PDF) on 20 March 2018 . Retrieved 3 July 2017 . ^ Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution . Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9 . OCLC 1082411117 . ^ "Social Role Theory of Sex Differences and Similarities : A Current Appraisal" . The Developmental Social Psychology of Gender . Psychology Press. 2000. pp. 137–188. doi : 10.4324/9781410605245-12 . ISBN 978-1-4106-0524-5 . Archived from the original on 30 April 2021 . Retrieved 10 June 2022 . ^ Blackstone, Amy (2003). "Gender Roles and Society" . In Miller, Julia R.; Lerner, Richard M.; Schiamberg, Lawrence B. (eds.). Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments . Sociology School Faculty Scholarship. Santa barbara, CA: ABC-CLIO. p. 335. Archived from the original on 16 May 2022 . Retrieved 30 July 2022 . ^ Nadal, Kevin L. (2017). The SAGE Encyclopedia of Psychology and Gender . SAGE Publications. p. 401. ISBN 978-1483384276 . Most cultures currently construct their societies based on the understanding of gender binary – the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization. ^ Herdt, Gilbert (2020). "Third Sexes and Third Genders". Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . Princeton, NJ: Princeton University Press. pp. 21–83. ISBN 978-1-942130-52-9 . Retrieved 30 July 2022 . ^ Trumbach, Randolph (1994). "London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture". In Herdt, Gilbert (ed.). Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . New York: Zone (MIT). pp. 111–136. ISBN 978-0-942299-82-3 . ^ Graham, Sharyn (April–June 2001). "Sulawesi's fifth gender" . Inside Indonesia . Archived from the original on 26 November 2014. ^ Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John ; Nieder, Timo O.; T'Sjoen, Guy (2016). "Non-binary or genderqueer genders" . International Review of Psychiatry . 28 (1): 95–102. doi : 10.3109/09540261.2015.1106446 . hdl : 1854/LU-7279758 . PMID 26753630 . S2CID 29985722 . Archived from the original on 26 June 2019 . Retrieved 9 June 2019 . ^ Ananthaswamy, Anil; Douglas, Kate. "The origins of sexism: How men came to rule 12,000 years ago" . New Scientist . Retrieved 7 March 2023 . ^ "What do we mean by "sex" and "gender"?" . World Health Organization . Archived from the original on 30 January 2017 . Retrieved 26 November 2015 . ^ Alters S, Schiff W (2009). Essential Concepts for Healthy Living . Jones & Bartlett Publishers . p. 143. ISBN 978-0-7637-5641-3 . Retrieved 3 January 2018 . ^ Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy . 21 (3): 416–438. doi : 10.1093/oxrep/gri024 . ^ Dobres, Marcia-Anne (27 November 2020). "Gender in the Earliest Human Societies" . In Meade, Teresa A.; Wiesner-Hanks, Merry E. (eds.). A Companion to Global Gender History (1 ed.). Wiley. pp. 183–204. doi : 10.1002/9781119535812.ch11 . ISBN 978-1-119-53580-5 . S2CID 229399965 . Archived from the original on 10 June 2022 . Retrieved 10 June 2022 . ^ "The Nature of Kinship: Overview" . www2.palomar.edu . Archived from the original on 3 December 2020 . Retrieved 24 October 2020 . ^ Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition" . Proceedings of the National Academy of Sciences of the United States of America . 117 (5): 2378–2384. Bibcode : 2020PNAS..117.2378I . doi : 10.1073/pnas.1917716117 . PMC 7007516 . PMID 31964846 . ^ Chandra, Kanchan (2012). Constructivist theories of ethnic politics . Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7 . OCLC 829678440 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389. In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of 'us' and 'them.' In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population. ^ Blackmore E (22 February 2019). "Race and ethnicity: How are they different?" . Culture . Archived from the original on 22 October 2020 . Retrieved 24 October 2020 . ^ Chandra K (2006). "What is Ethnic Identity and Does It Matter?" . Annual Review of Political Science . 9 (1): 397–424. doi : 10.1146/annurev.polisci.9.062404.170715 . ISSN 1094-2939 . ^ Smith AD (1999). Myths and Memories of the Nation . Oxford University Press. pp. 4–7. ^ Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism . 13 (1): 19–35. doi : 10.1111/j.1469-8129.2007.00271.x . ^ Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism . London: Sage. p. 171. ISBN 978-1-4129-0101-7 . ^ Christian D (2004). Maps of Time . University of California Press. ISBN 978-0-520-24476-4 . ^ Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?" . SAPIENS . Archived from the original on 7 August 2020 . Retrieved 24 October 2020 . ^ Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit" . Proceedings of the National Academy of Sciences of the United States of America . 115 (19): E4532–E4540. Bibcode : 2018PNAS..115E4532Z . doi : 10.1073/pnas.1708960115 . PMC 5948950 . PMID 29674447 . S2CID 4993139 . ^ Melina R (14 February 2011). "What Are the Different Types of Governments?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 24 October 2020 . ^ "Democracy Index 2021: less than half the world lives in a democracy" . The Economist Democracy Index . Economist Intelligence Unit . February 10, 2022. ^ Jeannie Evers (23 December 2012). "international organization" . National Geographic Society . Archived from the original on 27 April 2017 . Retrieved 24 October 2020 . ^ Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization . 58 (1): 1–29. doi : 10.1016/j.jebo.2004.03.009 . ISSN 0167-2681 . ^ Gibbons J (11 August 2015). "Why did Neanderthals go extinct?" . Smithsonian Insider . Archived from the original on 12 November 2020 . Retrieved 11 October 2020 . ^ University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?" . www.newswise.com . Archived from the original on 1 February 2021 . Retrieved 11 October 2020 . ^ Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years" . inews.co.uk . Archived from the original on 23 January 2021 . Retrieved 11 October 2020 . ^ Henriques M. "How spices changed the ancient world" . www.bbc.com . Archived from the original on 25 January 2021 . Retrieved 11 October 2020 . ^ Strauss IE (26 February 2016). "The Myth of the Barter Economy" . The Atlantic . Archived from the original on 15 February 2021 . Retrieved 11 October 2020 . ^ "The History of Money" . www.pbs.org . 26 October 1996. Archived from the original on 29 November 2020 . Retrieved 11 October 2020 . ^ "Why do we need economists and the study of economics?" . Federal Reserve Bank of San Francisco . July 2000. Archived from the original on 12 November 2020 . Retrieved 23 October 2020 . ^ Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong" . New Scientist . Archived from the original on 3 February 2021 . Retrieved 24 October 2020 . ^ Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates" . The Atlantic . Archived from the original on 7 May 2021 . Retrieved 7 May 2021 . ^ Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature . 538 (7624): 233–237. Bibcode : 2016Natur.538..233G . doi : 10.1038/nature19758 . PMID 27680701 . S2CID 4454927 . ^ Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF) . Nature . 538 (7624): 180–181. Bibcode : 2016Natur.538..180P . doi : 10.1038/nature19474 . PMID 27680700 . S2CID 4459560 . Archived (PDF) from the original on 20 May 2022 . Retrieved 30 July 2022 . ^ Ferguson RB (1 September 2018). "War Is Not Part of Human Nature" . Scientific American . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Ferguson N (September–October 2006). "The Next War of the World" . Foreign Affairs . Archived from the original on 25 April 2022 . Retrieved 30 July 2022 . ^ Beauchamp, Zack (June 23, 2015). "600 years of war and peace, in one amazing chart" . Vox . External links Listen to this article ( 1 hour and 16 minutes ) This audio file was created from a revision of this article dated 11 January 2022 ( 2022-01-11 ) , and does not reflect subsequent edits. ( Audio help · More spoken articles ) v t e Human evolution Taxonomy ( Hominins ) Last common ancestors Chimpanzee–human Gorilla–human Orangutan–human Gibbon–human Australopithecines Nakalipithecus Orrorin Sahelanthropus Kenyanthropus Ardipithecus A. kadabba A. ramidus Australopithecus A. afarensis A. africanus A. anamensis A. bahrelghazali A. deyiremeda A. garhi A. sediba Paranthropus P. aethiopicus P. boisei P. robustus Humans and proto-humans ( Homo ) Proto-humans H. gautengensis (?) H. habilis H. naledi H. rudolfensis (?) H. tsaichangensis (?) Homo erectus H. e. erectus H. e. georgicus H. e. lantianensis H. e. nankinensis H. e. pekinensis H. e. soloensis H. e. tautavelensis H. e. yuanmouensis Archaic humans H. antecessor Denisovans H. ergaster (?) H. floresiensis H. heidelbergensis H. longi (?) H. luzonensis H. neanderthalensis H. rhodesiensis (?) Modern humans Homo sapiens H. s. sapiens (archaic homo sapiens, anatomically modern humans) Jebel Irhoud H. s. idaltu Cro-Magnon Manot people Tam Pa Ling Red Deer Cave people Ancestors Homo habilis → Homo ergaster / Homo erectus (→ Homo antecessor ) → Homo heidelbergensis → archaic Homo sapiens → Homo sapiens Models General models Hunting Gathering Endurance running Aquatic ape Sexual selection Self-domestication Specific models Diet Cooking Expensive tissue Shore-based Drugs Drunken monkey Evolutionary models of human drug use Stoned ape theory Behavior Killer ape Cooperative eye Life history Grandmother Patriarch Topics Bipedalism Skeleton Muscles Skin color Hair Thermoregulation Speech Language Intelligence Gender roles Origin of modern humans Recent African origin Multiregional origin Archaic admixture Behavioral modernity Early migrations Recent evolution Timelines Human evolution Human prehistory Human timeline Others Theorists Books Fossils Evolutionary anthropology Paleoanthropology Human evolutionary developmental biology Category Commons Evolutionary biology Portal v t e Extant species of family Hominidae (great apes) Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Hominidae Ponginae Pongo (Orangutans) Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Homininae Gorilla (Gorillas) Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Hominini Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Homo (Humans) Human ( H. sapiens ) Category v t e Apes Extant ape species Homo Human ( H. sapiens ) Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Gorilla Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Orangutan Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Gibbon ( family : Hylobatidae) Study of apes Great ape language Dian Fossey Birutė Galdikas Jane Goodall Chimpanzee genome project Human Genome Project Gladys Kalema-Zikusoka Neanderthal genome project Willie Smits Lone Drøscher Nielsen Ian Redmond Elgin Center Iowa Primate Learning Sanctuary Borneo Orangutan Survival Primate archaeology Legal and social status Personhood Research ban Kinshasa Declaration on Great Apes Great Ape Project Great Apes Survival Partnership International Primate Day Nonhuman Rights Project Related Primate List of individual apes (non-human) Apes in space (non-human) Bigfoot Bushmeat Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor Gibbon–human last common ancestor List of fictional primates (non-human) Great apes Human evolution Monkey Day Mythic humanoids Yeren Yeti Yowie Category Humans at Wikipedia's sister projects : Definitions from Wiktionary Media from Commons Quotations from Wikiquote Texts from Wikisource Taxa from Wikispecies Taxon identifiers Homo sapiens Wikidata : Q15978631 ADW : Homo_sapiens BOLD : 12439 CoL : 6MB3T EoL : 327955 EPPO : HOMXSA GBIF : 2436436 iNaturalist : 43584 IRMNG : 10857762 ITIS : 180092 MDD : 1000718 MSW : 12100795 NBN : NHMSYS0000376773 NCBI : 9606 NZOR: d83185ac-1aa6-4f59-8645-fe8c040857b3 Observation.org : 83981 OBIS : 1455977 Open Tree of Life : 770315 Paleobiology Database : 83088 TSA : 8319 WoRMS : 1455977 ZooBank : 58D31D52-713D-44B4-9FE9-CB2D9249C422 Authority control databases International FAST National France BnF data Germany Israel Czech Republic Korea Other Encyclopedia of Modern Ukraine NARA İslâm Ansiklopedisi
Several terms redirect here. For other uses, see Human (disambiguation) , Mankind (disambiguation) , Humankind (disambiguation) , Human Race (disambiguation) , Human Being (disambiguation) , and Homo sapiens (disambiguation) .
Humans ( Homo sapiens ) or modern humans are the most common and widespread species of primate , and the last surviving species of the genus Homo . They are great apes characterized by their hairlessness , bipedalism , and high intelligence . Humans have large brains , enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools , and form complex social structures and civilizations . Humans are highly social , with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states . As such, social interactions between humans have established a wide variety of values, social norms , languages , and traditions (collectively termed institutions ), each of which bolsters human society . Humans are also highly curious : the desire to understand and influence phenomena has motivated humanity's development of science , technology , philosophy , mythology , religion , and other frameworks of knowledge ; humans also study themselves through such domains as anthropology , social science , history , psychology , and medicine . As of April 2024, there are estimated to be more than 8 billion humans alive .
Although some scientists equate the term "humans" with all members of the genus Homo , in common usage it generally refers to Homo sapiens , the only extant member. All other members of the genus Homo , which are now extinct, are known as archaic humans , and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa , they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence , interbreeding with Homo sapiens , or inability to adapt to climate change.
For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution , which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement ; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change . Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle.
Genes and the environment influence human biological variation in visible characteristics, physiology , disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic : generally, males have greater body strength and females have a higher body fat percentage. At puberty , humans develop secondary sex characteristics . Females are capable of pregnancy , usually between puberty, at around 12 years old, and menopause , around the age of 50.
Humans are omnivorous , capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus . Humans can survive for up to eight weeks without food and several days without water . Humans are generally diurnal , sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death . Often, both the mother and the father provide care for their children, who are helpless at birth .
Humans have a large, highly developed, and complex prefrontal cortex , the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory ; they have flexible facial expressions, self-awareness , and a theory of mind . The human mind is capable of introspection , private thought , imagination , volition , and forming views on existence . This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language .
All modern humans are classified into the species Homo sapiens , coined by Carl Linnaeus in his 1735 work Systema Naturae . The generic name " Homo " is a learned 18th-century derivation from Latin homō , which refers to humans of either sex. The word human can refer to all members of the Homo genus. The name " Homo sapiens " means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals , should be included as a separate species of humans or as a subspecies of H. sapiens .
Human is a loanword of Middle English from Old French humain , ultimately from Latin hūmānus , the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity ) as well as to human males. It may also refer to individuals of either sex.
Despite the fact that the word animal is colloquially used as an antonym for human , and contrary to a common biological misconception , humans are animals. The word person is often used interchangeably with human , but philosophical debate exists as to whether personhood applies to all humans or all sentient beings , and further if one can lose personhood (such as by going into a persistent vegetative state ).
Humans are apes ( superfamily Hominoidea ). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo ), then gorillas (genus Gorilla ), and finally, chimpanzees and bonobos (genus Pan ). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct.
The genus Homo evolved from Australopithecus . Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus . The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia , and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster ) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan . Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis , the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier.
The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second ( Southern Dispersal ) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii , Easter Island , Madagascar , and New Zealand in the years 300 to 1280 CE.
Human evolution was not a simple linear or branched progression but involved interbreeding between related species . Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans , may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans.
Human evolution is characterized by a number of morphological , developmental , physiological , and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees . The most significant of these adaptations are hairlessness , obligate bipedalism, increased brain size and decreased sexual dimorphism ( neoteny ). The relationship between all these changes is the subject of ongoing debate.
Hominoidea (hominoids, apes ) Hylobatidae ( gibbons ) Hominidae (hominids, great apes ) Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans)
Hylobatidae ( gibbons ) Hominidae (hominids, great apes ) Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans)
Ponginae Pongo ( orangutans ) Pongo abelii Pongo tapanuliensis Pongo pygmaeus Homininae (hominines) Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans)
Gorillini Gorilla ( gorillas ) Gorilla gorilla Gorilla beringei Hominini (hominins) Panina Pan ( chimpanzees ) Pan troglodytes Pan paniscus Hominina (homininans) Homo sapiens (humans)
Until about 12,000 years ago, all humans lived as hunter-gatherers . The Neolithic Revolution (the invention of agriculture ) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea , and the Sahel and West Savanna regions of Africa.
Access to food surplus led to the formation of permanent human settlements , the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations .
An urban revolution took place in the 4th millennium BCE with the development of city-states , particularly Sumerian cities located in Mesopotamia . It was in these cities that the earliest known form of writing, cuneiform script , appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation . They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture , Minoans and the Shang dynasty , rose to prominence in new areas. The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages . During this period iron started replacing bronze, leading to the Iron Age .
In the 5th century BCE, history started being recorded as a discipline , which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars . In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire 's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions.
Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages . During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age , inspiring achievements in architecture , the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England , the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims .
In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast . Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific.
The early modern period in Europe and the Near East ( c. 1450 –1800) began with the final defeat of the Byzantine Empire , and the rise of the Ottoman Empire . Meanwhile, Japan entered the Edo period , the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance , starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas . This expansion led to the Atlantic slave trade and the genocide of Native American peoples . This period also marked the Scientific Revolution , with great advances in mathematics , mechanics , astronomy and physiology .
The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology , major innovations in transport and energy development . The United States of America underwent great change, going from a small group of colonies to one of the global superpowers . The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World , while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania.
A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War , one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War , involving almost all of the world's countries . The war's destruction led to the collapse of most global empires, leading to widespread decolonization.
Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race , ending in the collapse of the Soviet Union. The current Information Age , spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected.
Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence , such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation , urban planning , construction, deforestation and desertification . Human settlements continue to be vulnerable to natural disasters , especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics , increasing knowledge or enhancing the exchange of resources.
Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms , although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa , India , Russia , Australia , Fiji , United States and Brazil (each located in a different biogeographical realm).
By using advanced tools and clothing , humans have been able to extend their tolerance to a wide variety of temperatures, humidities , and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest , arid desert , extremely cold arctic regions , and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth 's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%).
Within the last century, humans have explored challenging environments such as Antarctica, the deep sea , and outer space . Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific , military , or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft . Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station .
Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues , first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals.
In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums . Humans have had a dramatic effect on the environment . They are apex predators , being rarely preyed upon by other species. Human population growth , industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life.
Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.3 2.1.2.3 . Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth . Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars , with some individuals having them congenitally absent.
Humans share with chimpanzees a vestigial tail, appendix , flexible shoulder joints, grasping fingers and opposable thumbs . Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling , hearing and digesting proteins . While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair , most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet.
It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged . Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals.
Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger.
Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes , each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes . Like other mammals, humans have an XY sex-determination system , so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood.
While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years.
The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms . African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas . By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA , which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve , must have lived around 90,000 to 200,000 years ago.
Most human reproduction takes place by internal fertilization via sexual intercourse , but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus . Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions.
Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries.
Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth , humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy , childhood , adolescence , adulthood and old age . The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis ), rather than by continuing to bear children into old age.
The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018 , the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic , it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world , the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide.
Humans are omnivorous , capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous . In some cases, dietary restrictions in humans can lead to deficiency diseases ; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science .
Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game , which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus . Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture , a gradual process called the Neolithic Revolution . These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture.
In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation . Childhood malnutrition is also common and contributes to the global burden of disease . However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries . Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an " obesity epidemic ." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet.
There is biological variation in the human species – with traits such as blood type , genetic diseases , cranial features , facial features , organ systems , eye color , hair color and texture , height and build , and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin , and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet , exercise, and sleep patterns .
There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk . Sickle cell anemia , which may provide increased resistance to malaria , is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions , tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes . Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau .
Human hair ranges in color from red to blond to brown to black , which is the most frequent. Hair color depends on the amount of melanin , with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach , or even nearly white or colorless in cases of albinism . It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D , which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation.
There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other.
Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa , and particularly West Africa , have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans.
Humans are a gonochoric species, meaning they are divided into male and female sexes . The greatest degree of genetic variation exists between males and females . While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation . As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare.
The human brain , the focal point of the central nervous system in humans, controls the peripheral nervous system . In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion , it is also the locus of "higher" order functioning such as thought , reasoning , and abstraction . These cognitive processes constitute the mind , and, along with their behavioral consequences, are studied in the field of psychology .
Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition . This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to.
There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in " mental time travel ". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind .
Humans are generally diurnal . The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort.
During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep . The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming , where the dreamer is self-aware . Dreams can at times make a creative thought occur or give a sense of inspiration .
Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection , private thought , imagination and volition . It now often includes some kind of experience , cognition , feeling or perception . It may be 'awareness', or ' awareness of awareness ', or self-awareness . There might be different levels or orders of consciousness , or different kinds of consciousness, or just one kind with different features.
The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses , and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition , the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development . Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population.
Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization .
Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure . They are often intertwined with mood , temperament , personality , disposition , creativity , and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal.
Emotional experiences perceived as pleasant , such as joy , interest or contentment , contrast with those perceived as unpleasant , like anxiety , sadness , anger , and despair . Happiness , or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects , while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life . Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted.
For humans, sexuality involves biological , erotic , physical , emotional , social , or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions , including the human sexual response cycle . Sexuality also affects and is affected by cultural, political, legal, philosophical, moral , ethical , and religious aspects of life. Sexual desire, or libido , is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often.
Humans can fall anywhere along a continuous scale of sexual orientation , although most humans are heterosexual . While homosexual behavior occurs in some other animals , only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation , as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well.
Love most commonly refers to a feeling of strong attraction or emotional attachment . It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine , norepinephrine , serotonin and other chemicals stimulate the brain's pleasure center , leading to side effects such as increased heart rate , loss of appetite and sleep , and an intense feeling of excitement .
Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the " folk physics " required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning .
While many species communicate , language is unique to humans, a defining feature of humanity, and a cultural universal . Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement , using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors.
Language differs from other forms of communication in that it is modality independent ; the same meanings can be conveyed through different media, audibly in speech , visually by sign language or writing, and through tactile media such as braille . Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct .
Human arts can take many forms including visual , literary , and performing . Visual art can range from paintings and sculptures to film , fashion design , and architecture . Literary arts can include prose , poetry , and dramas . The performing arts generally involve theatre , music , and dance . Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation , video games , and medicine . As well as providing entertainment and transferring knowledge, the arts are also used for political purposes .
Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage.
Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures . There exists a wide variety of music genres and ethnic musics ; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment . Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain.
Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh , first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation.
Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated , thus proving essential in the development of agriculture – what is known as the Neolithic Revolution .
China developed paper , the printing press , gunpowder , the compass and other important inventions . The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel , which is used in railways , skyscrapers and many other products. This coincided with the Industrial Revolution , where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially , with major innovations in the 20th century including: electricity , penicillin , semiconductors , internal combustion engines , the Internet , nitrogen fixing fertilisers , airplanes , computers , automobiles , contraceptive pills , nuclear fission , the green revolution , radio , scientific plant breeding , rockets , air conditioning , television and the assembly line .
Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural , sacred or divine , and practices, values , institutions and rituals associated with such belief. Some religions also have a moral code . The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago ). It may have evolved to play a role in helping enforce and encourage cooperation between humans.
Religion manifests in diverse forms. Religion can include a belief in life after death , the origin of life , the nature of the universe ( religious cosmology ) and its ultimate fate ( eschatology ), and moral or ethical teachings . Views on transcendence and immanence vary substantially; traditions variously espouse monism , deism , pantheism , and theism (including polytheism and monotheism ).
Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims , Hindus and Buddhists . As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious , including those with no religious beliefs or no identity with any religion.
An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy.
Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period . Other early advances in science came from the Han dynasty in China and during the Islamic Golden Age . The scientific revolution , near the end of the Renaissance , led to the emergence of modern science .
A chain of events and influences led to the development of the scientific method , a process of observation and experimentation that is used to differentiate science from pseudoscience . An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition . All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics ), which are concerned with formal systems , the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics , chemistry , biology ) and social sciences (e.g., psychology , economics, sociology).
Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics , epistemology , logic , and axiology (which includes ethics and aesthetics ).
Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power , reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies .
Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex . The most common categorisation is a gender binary of men and women . Some societies recognise a third gender , or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female.
Gender roles are often associated with a division of norms , practices , dress , behavior , rights , duties , privileges , status , and power , with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct , gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic , while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal.
All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants ( consanguinity ), and relations through marriage ( affinity ). There is also a third type applied to godparents or adoptive children ( fictive ). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance . All societies have rules of incest taboo , according to which marriage between certain kinds of kin relations is prohibited, and some also have rules of preferential marriage with certain kin relations.
Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry , language , history , society , culture , nation , religion , or social treatment within their residing area. Ethnicity is separate from the concept of race , which is based on physical characteristics, although both are socially constructed . Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries.
As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances.
Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy , 17% in a hybrid regime , and 37% in an authoritarian regime . Many countries belong to international organizations and alliances ; the largest of these is the United Nations , with 193 member states .
Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian . The first truly international trade routes were around the spice trade through the Roman and medieval periods.
Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities ; the oldest being in the form of cattle and the most widely used being cowrie shells . Money has since evolved into governmental issued coins , paper and electronic money . Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population.
Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered , rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations, with rates of homicide about 0.01% in societies that have legal systems and strong cultural attitudes against violence.
The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war ) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict.
^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects. ^ Cities with over 10 million inhabitants as of 2018. ^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that.
^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects. ^ Cities with over 10 million inhabitants as of 2018. ^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that.
The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects.
Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma ), but recent research suggest it might be more complicated than that.
^ Groves CP (2005). Wilson DE , Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4 . OCLC 62265494 . ^ Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences . 149 (1): 109–114. JSTOR 4065043 . ^ Porkorny (1959). IEW . s.v. "g'hðem" pp. 414–116. ^ "Homo" . Dictionary.com Unabridged (v 1.1) . Random House. 23 September 2008. Archived from the original on 27 September 2008. ^ Barras, Colin (11 January 2016). "We don't know which species should be classed as 'human' " . BBC . Archived from the original on 26 August 2021 . Retrieved 31 March 2021 . ^ Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758" . Proceedings of the Academy of Natural Sciences of Philadelphia . 149 : 109–114. ISSN 0097-3157 . JSTOR 4065043 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . ^ OED . s.v. "human". ^ "Man" . Merriam-Webster Dictionary . Archived from the original on 22 September 2017 . Retrieved 14 September 2017 . Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination ^ "Thesaurus results for human" . Merriam-Webster Dictionary . Archived from the original on 28 June 2022 . Retrieved 21 May 2022 . ^ "Misconceptions about evolution – Understanding Evolution" . University of California, Berkeley . 19 September 2021. Archived from the original on 6 June 2022 . Retrieved 21 May 2022 . ^ "Concept of Personhood" . University of Missouri School of Medicine . Archived from the original on 4 March 2021 . Retrieved 4 July 2021 . ^ Tuttle RH (4 October 2018). "Hominoidea: conceptual history" . In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology . Hoboken , New Jersey , United States : John Wiley & Sons, Inc. pp. 1–2. doi : 10.1002/9781118584538.ieba0246 . ISBN 978-1-118-58442-2 . S2CID 240125199 . Retrieved 26 May 2021 . ^ Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution . 30 (3): 260–266. Bibcode : 1990JMolE..30..260G . doi : 10.1007/BF02099995 . PMID 2109087 . S2CID 2112935 . ^ Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets" . Molecular Biology and Evolution . 14 (3): 248–265. doi : 10.1093/oxfordjournals.molbev.a025761 . PMID 9066793 . ^ MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes" . Evolution pages . Archived from the original on 9 August 2011 . Retrieved 18 May 2006 . ^ McNulty, Kieran P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?" . Nature Education Knowledge . Archived from the original on 10 January 2016 . Retrieved 11 June 2022 . ^ Strait DS (September 2010). "The Evolutionary History of the Australopiths" . Evolution: Education and Outreach . 3 (3): 341–352. doi : 10.1007/s12052-010-0249-6 . ISSN 1936-6434 . S2CID 31979188 . ^ Dunsworth HM (September 2010). "Origin of the Genus Homo" . Evolution: Education and Outreach . 3 (3): 353–366. doi : 10.1007/s12052-010-0247-8 . ISSN 1936-6434 . S2CID 43116946 . ^ Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1698): 20150248. doi : 10.1098/rstb.2015.0248 . PMC 4920303 . PMID 27298460 . S2CID 20267830 . ^ Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia" . Science . 347 (6228): 1352–1355. Bibcode : 2015Sci...347.1352V . doi : 10.1126/science.aaa1343 . PMID 25739410 . ^ Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature . 559 (7715): 608–612. Bibcode : 2018Natur.559..608Z . doi : 10.1038/s41586-018-0299-4 . PMID 29995848 . S2CID 49670311 . ^ Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF) . Nature . 546 (7657): 289–292. Bibcode : 2017Natur.546..289H . doi : 10.1038/nature22336 . PMID 28593953 . S2CID 256771372 . Archived (PDF) from the original on 8 January 2020 . Retrieved 30 July 2022 . ^ "Out of Africa Revisited". Science (This Week in Science ). 308 (5724): 921. 13 May 2005. doi : 10.1126/science.308.5724.921g . ISSN 0036-8075 . S2CID 220100436 . ^ Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature . 423 (6941): 692–693, 695. Bibcode : 2003Natur.423..692S . doi : 10.1038/423692a . PMID 12802315 . S2CID 26693109 . ^ Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?" . actionbioscience . Washington, DC: American Institute of Biological Sciences . Archived from the original on 17 June 2021 . Retrieved 23 November 2009 . ^ Marean, Curtis; et al. (2007). "Early human use of marine resources and pigment in South Africa during the Middle Pleistocene" (PDF) . Nature . 449 (7164): 905–908. Bibcode : 2007Natur.449..905M . doi : 10.1038/nature06204 . PMID 17943129 . S2CID 4387442 . Archived (PDF) from the original on 2023-05-25 . Retrieved 2023-01-07 . ^ Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB (2018). "Long-distance stone transport and pigment use in the earliest Middle Stone Age" . Science . 360 (6384): 90–94. Bibcode : 2018Sci...360...90B . doi : 10.1126/science.aao2646 . PMID 29545508 . ^ Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology . 26 (6): 827–833. Bibcode : 2016CBio...26..827P . doi : 10.1016/j.cub.2016.01.037 . hdl : 2440/114930 . PMID 26853362 . S2CID 140098861 . ^ Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture" . Genome Research . 25 (4): 459–466. doi : 10.1101/gr.186684.114 . PMC 4381518 . PMID 25770088 . ^ Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia" . Science . 331 (6016): 453–456. Bibcode : 2011Sci...331..453A . doi : 10.1126/science.1199113 . PMID 21273486 . S2CID 20296624 . Archived from the original on 27 April 2011 . Retrieved 1 May 2011 . ^ Rincon P (27 January 2011). "Humans 'left Africa much earlier' " . BBC News . Archived from the original on 9 August 2012. ^ Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature . 547 (7663): 306–310. Bibcode : 2017Natur.547..306C . doi : 10.1038/nature22968 . hdl : 2440/107043 . PMID 28726833 . S2CID 205257212 . ^ Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF) . University of Waikato . Archived (PDF) from the original on 22 May 2010 . Retrieved 29 April 2010 . ^ Appenzeller T (May 2012). "Human migrations: Eastern odyssey" . Nature . 485 (7396): 24–26. Bibcode : 2012Natur.485...24A . doi : 10.1038/485024a . PMID 22552074 . ^ Reich D , Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" . Nature . 468 (7327): 1053–1060. Bibcode : 2010Natur.468.1053R . doi : 10.1038/nature09710 . hdl : 10230/25596 . PMC 4306417 . PMID 21179161 . ^ Hammer MF (May 2013). "Human Hybrids" (PDF) . Scientific American . 308 (5): 66–71. Bibcode : 2013SciAm.308e..66H . doi : 10.1038/scientificamerican0513-66 . PMID 23627222 . Archived from the original (PDF) on 24 August 2018. ^ Yong E (July 2011). "Mosaic humans, the hybrid species" . New Scientist . 211 (2823): 34–38. Bibcode : 2011NewSc.211...34Y . doi : 10.1016/S0262-4079(11)61839-3 . ^ Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology . 43 (1): 1–11. doi : 10.1007/s11692-015-9348-1 . S2CID 14329491 . ^ Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans" . Genome Research . 20 (5): 547–553. doi : 10.1101/gr.076000.108 . PMC 2860157 . PMID 20439435 . ^ Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans" . Science . 334 (6052): 89–94. Bibcode : 2011Sci...334...89A . doi : 10.1126/science.1209202 . PMC 3677943 . PMID 21868630 . ^ Sandel, Aaron A. (30 July 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness" . American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . Archived from the original on 22 July 2023 . Retrieved 22 July 2023 . ^ Boyd R , Silk JB (2003). How Humans Evolved . New York: Norton . ISBN 978-0-393-97854-4 . ^ Little, Michael A.; Blumler, Mark A. (2015). "Hunter-Gatherers" . In Muehlenbein, Michael P. (ed.). Basics in Human Evolution . Boston: Academic Press. pp. 323–335. ISBN 978-0-12-802652-6 . Archived from the original on 3 July 2022 . Retrieved 30 July 2022 . ^ Scarre, Chris (2018). "The world transformed: from foragers and farmers to states and empires". In Scarre, Chris (ed.). The Human Past: World Prehistory and the Development of Human Societies (4th ed.). London: Thames & Hudson . pp. 174–197. ISBN 978-0-500-29335-5 . ^ Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe . Walnut Creek, CA: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5 . OCLC 855969933 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society . Elsevier. pp. 103–131. doi : 10.1016/B978-0-12-805247-1.00006-X . ISBN 978-0-12-805247-1 . ^ He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China" . The Holocene . 27 (12): 1885–1898. Bibcode : 2017Holoc..27.1885H . doi : 10.1177/0959683617708455 . S2CID 133660098 . Archived from the original on 20 November 2021 . Retrieved 30 July 2022 . ^ Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago" . Proceedings of the National Academy of Sciences of the United States of America . 106 (18): 7367–7372. Bibcode : 2009PNAS..106.7367L . doi : 10.1073/pnas.0900158106 . PMC 2678631 . PMID 19383791 . ^ Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea" . Science . 301 (5630): 189–193. doi : 10.1126/science.1085255 . PMID 12817084 . S2CID 10644185 . ^ Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication" . Science Advances . 5 (5): eaaw1947. Bibcode : 2019SciA....5.1947S . doi : 10.1126/sciadv.aaw1947 . PMC 6527260 . PMID 31114806 . ^ Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF) . Current Anthropology . 58 (5): 673–683. doi : 10.1086/693898 . S2CID 149402650 . Archived (PDF) from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science . 38 (2): 312–322. Bibcode : 2011JArSc..38..312M . doi : 10.1016/j.jas.2010.09.007 . ^ Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries . Cengage Learning. ISBN 978-1-285-66153-7 . Archived from the original on 27 February 2021 . Retrieved 11 July 2015 . ^ Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500 . Cenpage Learning. ISBN 978-1-285-98299-1 . Archived from the original on 10 August 2023 . Retrieved 11 July 2015 . ^ Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization . San Francisco: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3 . Archived from the original on 10 August 2023 . Retrieved 30 July 2022 . ^ Garfinkle, Steven J. (2013). "Ancient Near Eastern City-States". In Peter Fibiger Bang ; Walter Scheidel (eds.). The Oxford Handbook of the State in the Ancient Near East and Mediterranean . Oxford Academic. pp. 94–119. doi : 10.1093/oxfordhb/9780195188318.013.0004 . ISBN 978-0-19-518831-8 . ^ Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi : 10.1002/9781119193814.ch2 . ISBN 978-1-119-19329-6 . S2CID 216180781 . ^ Robinson A (October 2015). "Ancient civilization: Cracking the Indus script" . Nature . 526 (7574): 499–501. Bibcode : 2015Natur.526..499R . doi : 10.1038/526499a . PMID 26490603 . S2CID 4458743 . ^ Crawford H (2013). "Trade in the Sumerian world". The Sumerian World . Routledge. pp. 447–461. ISBN 978-1-136-21911-5 . ^ Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles" . Acta Archaeologica Academiae Scientiarum Hungaricae . 69 (2): 271–298. doi : 10.1556/072.2018.69.2.3 . ISSN 0001-5210 . S2CID 115685157 . Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ Pryor FL (1985). "The Invention of the Plow" . Comparative Studies in Society and History . 27 (4): 727–743. doi : 10.1017/S0010417500011749 . ISSN 0010-4175 . JSTOR 178600 . S2CID 144840498 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Carter R (2012). "19. Watercraft ". In Potts DT (ed.). A companion to the archaeology of the ancient Near East . Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0 . Archived from the original on 28 April 2015 . Retrieved 8 February 2014 . ^ Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction . CUP Archive. p. 1. ISBN 978-0-521-40340-5 . ^ Robson E (2008). Mathematics in ancient Iraq: A social history . Princeton University Press. pp. xxi. ^ Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza" . Technology and Culture . 44 (2): 340–354. doi : 10.1353/tech.2003.0063 . ISSN 0040-165X . JSTOR 25148110 . S2CID 109998651 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Voosen P (August 2018). "New geological age comes under fire". Science . 361 (6402): 537–538. Bibcode : 2018Sci...361..537V . doi : 10.1126/science.361.6402.537 . PMID 30093579 . S2CID 51954326 . ^ Saggs HW (2000). Babylonians . Univ of California Press. p. 7. ISBN 978-0-520-20222-1 . ^ Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory . 12 (4): 335–364. doi : 10.1007/s10816-005-8460-4 . ISSN 1573-7764 . S2CID 53393440 . ^ Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans" . Nature . 548 (7666): 214–218. Bibcode : 2017Natur.548..214L . doi : 10.1038/nature23310 . PMC 5565772 . PMID 28783727 . ^ Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC . Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8 . ^ Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change . 6 (4): 369–382. Bibcode : 2015WIRCC...6..369K . doi : 10.1002/wcc.345 . S2CID 128460316 . ^ Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science . 39 (6): 1862–1870. Bibcode : 2012JArSc..39.1862D . doi : 10.1016/j.jas.2012.01.029 . ^ Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory . Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi : 10.1007/978-1-4419-6633-9_11 . ISBN 978-1-4419-6633-9 . ^ Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography . United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1 . ^ Beard M (2 October 2015). "Why ancient Rome matters to the modern world" . The Guardian . Archived from the original on 14 April 2021 . Retrieved 17 April 2021 . ^ Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece" . Stanford University . Archived from the original on 18 April 2021 . Retrieved 17 April 2021 . ^ Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature . 582 (7813): 530–533. Bibcode : 2020Natur.582..530I . doi : 10.1038/s41586-020-2343-4 . PMID 32494009 . S2CID 219281856 . ^ Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar" . Latin American Antiquity . 28 (1): 88–104. doi : 10.1017/laq.2016.4 . ISSN 1045-6635 . S2CID 164417025 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida" . Proceedings of the Seminar for Arabian Studies . 46 : 25–40. ISSN 0308-8421 . JSTOR 45163415 . Archived from the original on 28 April 2022 . Retrieved 30 July 2022 . ^ Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration . 21 (1): 25–86. doi : 10.1080/01900699808525297 . ISSN 0190-0692 . ^ Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age" . Journal of the American Oriental Society . 96 (1): 15–26. doi : 10.2307/599886 . ISSN 0003-0279 . JSTOR 599886 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 . ^ Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty" . Architectural History . 63 : 1–36. doi : 10.1017/arh.2020.1 . ISSN 0066-622X . S2CID 229716130 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question" . Climate . 6 (4): 90. Bibcode : 2018Clim....6...90M . doi : 10.3390/cli6040090 . ^ Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World . New York: Oxford University Press. p. 72. ISBN 978-0-19-532819-6 . Retrieved 30 July 2022 . ^ Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies . International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi : 10.1007/978-3-319-24774-8_2 . ISBN 978-3-319-24774-8 . ^ Vidal-Nanquet P (1987). The Harper Atlas of World History . Harper & Row Publishers. p. 76. ^ Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land . Simon and Schuster. ISBN 978-1-84983-770-5 . ^ Adam King (2002). "Mississippian Period: Overview" . New Georgia Encyclopedia . Archived from the original on 19 August 2009 . Retrieved 15 November 2009 . ^ Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism . Cambridge University Press. p. 2. ISBN 0-521-31896-3 . ^ May T (2013). The Mongol Conquests in World History . Reaktion Books. p. 7. ISBN 978-1-86189-971-2 . ^ Canós-Donnay S (25 February 2019). "The Empire of Mali" . Oxford Research Encyclopedia of African History . Oxford University Press. doi : 10.1093/acrefore/9780190277734.013.266 . ISBN 978-0-19-027773-4 . Archived from the original on 20 October 2021 . Retrieved 7 May 2021 . ^ Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity" . Asian Perspectives . 37 (2): 135–164. ^ Kafadar C (1 January 1994). "Ottomans and Europe" . In Brady T, Oberman T, Tracy JD (eds.). Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation . Brill. pp. 589–635. doi : 10.1163/9789004391659_019 . ISBN 978-90-04-39165-9 . Archived from the original on 2 May 2022 . Retrieved 17 April 2021 . ^ Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan" . Oxford Research Encyclopedia of Asian History . Oxford University Press. doi : 10.1093/acrefore/9780190277727.013.72 . ISBN 978-0-19-027772-7 . Archived from the original on 12 August 2021 . Retrieved 7 May 2021 . ^ Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing" . Pacific Affairs . 83 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526–1857)" . Al-Ta Lim Journal . 23 (2): 128–138. doi : 10.15548/jt.v23i2.228 . ISSN 2355-7893 . Archived from the original on 7 April 2022 . Retrieved 30 July 2022 . ^ Kirkpatrick R (2002). The European Renaissance, 1400–1600 . Routledge. p. 1. ISBN 978-1-317-88646-4 . OCLC 893909816 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Arnold D (2002). The Age of Discovery, 1400–1600 (Second ed.). Routledge. pp. xi. ISBN 978-1-136-47968-7 . OCLC 859536800 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics" . Theoretical Inquiries in Law . 11 (1). doi : 10.2202/1565-3404.1239 . ISSN 1565-3404 . S2CID 56216309 . Archived from the original on 26 August 2021 . Retrieved 30 July 2022 . ^ Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews . 20 (1–3): 277–299. Bibcode : 2001QSRv...20..277J . doi : 10.1016/S0277-3791(00)00116-5 . ^ Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature" . The Journal of African History . 30 (3): 365–394. doi : 10.1017/S0021853700024439 . ISSN 0021-8537 . JSTOR 182914 . S2CID 161321949 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide . London: Palgrave Macmillan UK. pp. 273–295. doi : 10.1057/9780230297784_11 . ISBN 978-0-230-29778-4 . ^ Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour . 38 (3–4): 157–158. doi : 10.1016/j.endeavour.2014.10.001 . PMID 25457642 . ^ "Greatest Engineering Achievements of the 20th Century" . National Academy of Engineering . Archived from the original on 6 April 2015 . Retrieved 7 April 2015 . ^ Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776 . New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0 . OCLC 299054528 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815" . Journal of Global History . 1 (1): 123–149. doi : 10.1017/S1740022806000076 . ISSN 1740-0228 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Zimmerman AF (November 1931). "Spain and Its Colonies, 1808–1820" . The Hispanic American Historical Review . 11 (4): 439–463. doi : 10.2307/2506251 . JSTOR 2506251 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 . ^ David S (2011). "British History in depth: Slavery and the 'Scramble for Africa' " . BBC . Archived from the original on 24 March 2022 . Retrieved 5 May 2021 . ^ Raudzens G (2004). "The Australian Frontier Wars, 1788–1838 (review)" . The Journal of Military History . 68 (3): 957–959. doi : 10.1353/jmh.2004.0138 . ISSN 1543-7795 . S2CID 162259092 . ^ Clark CM (2012). "Polarization of Europe, 1887–1907". The sleepwalkers : how Europe went to war in 1914 . London: Allen Lane. ISBN 978-0-7139-9942-6 . OCLC 794136314 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Robert Dahl (1989). Democracy and Its Critics . Yale UP. pp. 239–240 . ISBN 0-300-15355-4 . ^ McDougall WA (May 1985). "Sputnik, the space race, and the Cold War" . Bulletin of the Atomic Scientists . 41 (5): 20–25. Bibcode : 1985BuAtS..41e..20M . doi : 10.1080/00963402.1985.11455962 . ISSN 0096-3402 . ^ Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?" . Journal of Peace Research . 30 (2): 163–179. doi : 10.1177/0022343393030002004 . ISSN 0022-3433 . S2CID 5482851 . Archived from the original on 21 February 2022 . Retrieved 30 July 2022 . ^ Sachs JD (April 2017). "Globalization – In the Name of Which Freedom?" . Humanistic Management Journal . 1 (2): 237–252. doi : 10.1007/s41463-017-0019-5 . ISSN 2366-603X . S2CID 133030709 . ^ "World" . The World Factbook . CIA . 17 May 2016. Archived from the original on 26 January 2021 . Retrieved 2 October 2016 . ^ "World Population Prospects: The 2017 Revision" (PDF) . United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17. Archived (PDF) from the original on 26 June 2019 . Retrieved 30 July 2022 . ^ "The World's Cities in 2018" (PDF) . United Nations . Archived (PDF) from the original on 1 November 2018. ^ Rector RK (2016). The Early River Valley Civilizations (First ed.). New York: Rosen Publishing. p. 10. ISBN 978-1-4994-6329-3 . OCLC 953735302 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ "How People Modify the Environment" (PDF) . Westerville City School District . Archived (PDF) from the original on 25 February 2021 . Retrieved 13 March 2019 . ^ "Natural disasters and the urban poor" (PDF) . World Bank . October 2003. Archived (PDF) from the original on 9 August 2017. ^ Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities . [London]: Routledge. pp. x. ISBN 978-1-135-01559-6 . OCLC 889953315 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Piantadosi CA (2003). The biology of human survival : life and death in extreme environments . Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5 . OCLC 70215878 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Toups, M.A.; Kitchen, A.; Light, J.E.; Reed, D.L. (2011). "Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa" . Molecular Biology and Evolution . 28 (1): 29–32. doi : 10.1093/molbev/msq234 . PMC 3002236 . PMID 20823373 . ^ O'Neil D. "Human Biological Adaptability; Overview" . Palomar College. Archived from the original on 6 March 2013 . Retrieved 6 January 2013 . ^ "Population distribution and density" . BBC. Archived from the original on 23 June 2017 . Retrieved 26 June 2017 . ^ Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management . 30 (4): 492–507. doi : 10.1007/s00267-002-2737-0 . hdl : 10072/6758 . PMID 12481916 . S2CID 25834286 . ^ Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica" . Vanderbilt Journal of Transnational Law . 23 : 819. Archived from the original on 23 June 2021 . Retrieved 30 July 2022 . ^ "Mission to Mars: Mars Science Laboratory Curiosity Rover" . Jet Propulsion Laboratory. Archived from the original on 18 August 2015 . Retrieved 26 August 2015 . ^ "Touchdown! Rosetta's Philae probe lands on comet" . European Space Agency. 12 November 2014. Archived from the original on 22 August 2015 . Retrieved 26 August 2015 . ^ "NEAR-Shoemaker" . NASA . Archived from the original on 26 August 2015 . Retrieved 26 August 2015 . ^ Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station" . JSC Features . Johnson Space Center . Archived from the original on 16 February 2012 . Retrieved 13 February 2012 . ^ Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth" . Proceedings of the National Academy of Sciences of the United States of America . 115 (25): 6506–6511. Bibcode : 2018PNAS..115.6506B . doi : 10.1073/pnas.1711842115 . PMC 6016768 . PMID 29784790 . ^ Tellier LN (2009). Urban world history: an economic and geographical perspective . Presses de l'Université du Québec. p. 26. ISBN 978-2-7605-1588-8 . Retrieved 30 July 2022 . ^ Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, CA: Dickenson Pub. Co. ISBN 978-0-8221-0166-6 . ^ Harl KW (1998). "Population estimates of the Roman Empire" . Tulane.edu. Archived from the original on 7 May 2016 . Retrieved 8 December 2012 . ^ Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis" . International Journal of Hygiene and Environmental Health . 207 (2): 165–178. doi : 10.1078/1438-4639-00259 . PMC 7128933 . PMID 15031959 . ^ "World's population reaches six billion" . BBC News . 5 August 1999. Archived from the original on 15 April 2008 . Retrieved 5 February 2008 . ^ United Nations. "World population to reach 8 billion on 15 November 2022" . United Nations . Archived from the original on 20 January 2023 . Retrieved 27 October 2022 . ^ "Eight billion people, SARS-CoV-2 ancestor and illegal fishing" . Nature . 611 (641): 641. 23 November 2022. Bibcode : 2022Natur.611..641. . doi : 10.1038/d41586-022-03792-4 . S2CID 253764233 . Archived from the original on 26 January 2023 . Retrieved 26 January 2023 . ^ "World Population to Hit Milestone With Birth of 7 Billionth Person" . PBS NewsHour . 27 October 2011. Archived from the original on 24 September 2017 . Retrieved 11 February 2018 . ^ "68% of the world population projected to live in urban areas by 2050, says UN" . United Nations Department of Economic and Social Affairs (DESA) . 16 May 2018. Archived from the original on 10 March 2021 . Retrieved 18 April 2021 . ^ Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF) . U.S. Department of Justice , Bureau of Justice Statistics. Archived (PDF) from the original on 24 February 2013 . Retrieved 1 October 2006 . ^ Roopnarine PD (March 2014). "Humans are apex predators" . Proceedings of the National Academy of Sciences of the United States of America . 111 (9): E796. Bibcode : 2014PNAS..111E.796R . doi : 10.1073/pnas.1323645111 . PMC 3948303 . PMID 24497513 . ^ Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature" . Science . AAAS . Archived from the original on 26 October 2021 . Retrieved 9 May 2021 . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use – principally agriculture – that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.) ^ Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions" . Proceedings of the National Academy of Sciences of the United States of America . 103 (29): 10941–10946. Bibcode : 2006PNAS..10310941P . doi : 10.1073/pnas.0604181103 . PMC 1544153 . PMID 16829570 . ^ Collins D (1976). The Human Revolution: From Ape to Artist . Phaidon. p. 208 . ISBN 978-0-7148-1676-0 . ^ Weisberger, Mindy (March 23, 2024). "Why don't humans have tails? Scientists find answers in an unlikely place" . CNN . Archived from the original on March 24, 2024 . Retrieved March 24, 2024 . ^ Marks JM (2001). Human Biodiversity: Genes, Race, and History . Transaction Publishers. p. 16. ISBN 978-0-202-36656-2 . ^ Gea, J (2008). "The Evolution of the Human Species: A Long Journey for the Respiratory System". Archivos de Bronconeumología ((English Edition)) . 44 (5): 263–270. doi : 10.1016/S1579-2129(08)60042-7 . ^ O'Neil D. "Humans" . Primates . Palomar College. Archived from the original on 11 January 2013 . Retrieved 6 January 2013 . ^ "How to be Human: The reason we are so scarily hairy" . New Scientist . 2017. Archived from the original on 25 February 2021 . Retrieved 29 April 2020 . ^ Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . ^ Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White" . Evolution: Library . PBS. Archived from the original on 16 February 2013 . Retrieved 6 January 2013 . ^ Roser M, Appel C, Ritchie H (8 October 2013). "Human Height" . Our World in Data . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ "Senior Citizens Do Shrink – Just One of the Body Changes of Aging" . News . Senior Journal. Archived from the original on 19 February 2013 . Retrieved 6 January 2013 . ^ Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology . 136 (1): 71–84. doi : 10.1016/S1095-6433(02)00294-5 . PMID 14527631 . ^ "Human weight" . Articleworld.org. Archived from the original on 8 December 2011 . Retrieved 10 December 2011 . ^ Schlessingerman A (2003). "Mass Of An Adult" . The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018 . Retrieved 31 December 2017 . ^ Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology) . Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1 . Retrieved 5 April 2009 . ^ Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care" . British Journal of Anaesthesia . 85 (1): 91–108. doi : 10.1093/bja/85.1.91 . PMID 10927998 . ^ Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology . 93 (1): 1–16. doi : 10.1086/696721 . ISSN 0033-5770 . S2CID 90757192 . ^ Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance" . The New York Times . Archived from the original on 5 November 2015. ^ John B. "What is the role of sweating glands in balancing body temperature when running a marathon?" . Livestrong.com. Archived from the original on 31 January 2013 . Retrieved 6 January 2013 . ^ Shave, R. E.; Lieberman, D. E.; Drane, A. L.; et al. (2019). "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart" . PNAS . 116 (40): 19905–19910. Bibcode : 2019PNAS..11619905S . doi : 10.1073/pnas.1906902116 . PMC 6778238 . PMID 31527253 . ^ Ríos, L; Sleeper, M. M.; Danforth, M. D.; et al. (2023). "The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution" . Scientific Reports . 13 (6841): 6841. Bibcode : 2023NatSR..13.6841R . doi : 10.1038/s41598-023-33675-1 . hdl : 10261/309357 . PMC 10133235 . PMID 37100851 . ^ Therman E (1980). Human Chromosomes: Structure, Behavior, Effects . Springer US . pp. 112–124. doi : 10.1007/978-1-4684-0107-3 . ISBN 978-1-4684-0109-7 . S2CID 36686283 . ^ Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex" . Journal of Medical Genetics . 3 (2): 117–123. doi : 10.1136/jmg.3.2.117 . PMC 1012913 . PMID 6007033 . ^ Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics . 61 (3): 216–228. doi : 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S . PMID 8741866 . ^ Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics . 53 (1): 27–34. doi : 10.1038/s41588-020-00755-1 . PMID 33414551 . S2CID 230986741 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . Between any two humans, the amount of genetic variation – biochemical individuality – is about 0.1%. ^ Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human" . PLOS Biology . 5 (10): e254. doi : 10.1371/journal.pbio.0050254 . PMC 1964779 . PMID 17803354 . ^ Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research" . American Journal of Human Genetics . 77 (4): 519–532. doi : 10.1086/491747 . PMC 1275602 . PMID 16175499 . ^ "Chimps show much greater genetic diversity than humans" . Media . University of Oxford. Archived from the original on 18 December 2013 . Retrieved 13 December 2013 . ^ Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography" . Proceedings of the National Academy of Sciences of the United States of America . 95 (4): 1961–1967. Bibcode : 1998PNAS...95.1961H . doi : 10.1073/pnas.95.4.1961 . PMC 19224 . PMID 9465125 . ^ Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans" . Proceedings of the National Academy of Sciences of the United States of America . 94 (7): 3100–3103. Bibcode : 1997PNAS...94.3100J . doi : 10.1073/pnas.94.7.3100 . PMC 20328 . PMID 9096352 . ^ Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story" . The New York Times . Archived from the original on 14 January 2012 . Retrieved 13 February 2012 . ^ Pennisi E (February 2001). "The human genome". Science . 291 (5507): 1177–1180. doi : 10.1126/science.291.5507.1177 . PMID 11233420 . S2CID 38355565 . ^ Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature . 590 (7845): 220–221. Bibcode : 2021Natur.590..220R . doi : 10.1038/d41586-021-00237-2 . PMID 33568827 . S2CID 231882262 . ^ Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations" . Nature . 467 (7311): 52–58. Bibcode : 2010Natur.467...52T . doi : 10.1038/nature09298 . PMC 3173859 . PMID 20811451 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private , common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture. ^ Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes" . Genome Biology . 11 (5): 206. doi : 10.1186/gb-2010-11-5-206 . PMC 2898077 . PMID 20441615 . ^ Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature . 325 (6099): 31–36. Bibcode : 1987Natur.325...31C . doi : 10.1038/325031a0 . PMID 3025745 . S2CID 4285418 . ^ Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock" . American Journal of Human Genetics . 84 (6): 740–759. doi : 10.1016/j.ajhg.2009.05.001 . PMC 2694979 . PMID 19500773 . ^ "University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history" . 20 August 2017. Archived from the original on 20 August 2017. ^ Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females" . Science . 341 (6145): 562–565. Bibcode : 2013Sci...341..562P . doi : 10.1126/science.1237619 . PMC 4032117 . PMID 23908239 . ^ Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set . John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1 . ^ Jukic AM, Baird DD, Weinberg CR , McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation" . Human Reproduction . 28 (10): 2848–2855. doi : 10.1093/humrep/det297 . PMC 3777570 . PMID 23922246 . ^ Klossner NJ (2005). Introductory Maternity Nursing . Lippincott Williams & Wilkins. p. 103. ISBN 978-0-7817-6237-3 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . The fetal stage is from the beginning of the 9th week after fertilization and continues until birth ^ World Health Organization (November 2014). "Preterm birth Fact sheet N°363" . who.int . Archived from the original on 7 March 2015 . Retrieved 6 March 2015 . ^ Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application" . American Journal of Obstetrics and Gynecology . 218 (2S): S619–S629. doi : 10.1016/j.ajog.2017.12.010 . PMID 29422204 . S2CID 46810955 . ^ "What is the average baby length? Growth chart by month" . www.medicalnewstoday.com . 18 March 2019. Archived from the original on 27 January 2021 . Retrieved 18 April 2021 . ^ Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal . 5 (2): 113–122. PMID 15024783 . ^ Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology . 35 (S15): 89–124. doi : 10.1002/ajpa.1330350605 . ISSN 1096-8644 . ^ Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma" . American Journal of Obstetrics and Gynecology . 222 (1): 3–16. doi : 10.1016/j.ajog.2019.06.043 . PMC 9069416 . PMID 31251927 . S2CID 195761874 . ^ Barras C (22 December 2016). "The real reasons why childbirth is so painful and dangerous". BBC. ^ Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?" . Newsweek . Archived from the original on 28 June 2007. A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa , compared to 1 in 2,800 in developed countries . ^ Rush D (July 2000). "Nutrition and maternal mortality in the developing world" . The American Journal of Clinical Nutrition . 72 (1 Suppl): 212S–240S. doi : 10.1093/ajcn/72.1.212S . PMID 10871588 . ^ Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour . Oxford University Press. p. 7. ISBN 978-0-19-958696-7 . Retrieved 30 July 2022 . ^ Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning . p. 296. ISBN 978-0-495-60037-4 . Archived from the original on 3 October 2023 . Retrieved 30 July 2022 . ^ Schuiling KD, Likis FE (2016). Women's Gynecologic Health . Jones & Bartlett Learning . p. 22. ISBN 978-1-284-12501-6 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13. ^ Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy . SAGE Publications . pp. 18–19. ISBN 978-1-4833-6475-9 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average). ^ Mintz S (1993). "Life stages". Encyclopedia of American Social History . 3 : 7–33. ^ Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?" . Indian Journal of Endocrinology and Metabolism . 18 (Suppl 1): S53-62. doi : 10.4103/2230-8210.145075 . PMC 4266869 . PMID 25538878 . ^ Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?" . Biology of Reproduction . 79 (3): 398–406. doi : 10.1095/biolreprod.108.068536 . PMC 2553520 . PMID 18495681 . ^ Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality . New York: Basic Books. pp. 167–170. ISBN 978-0-465-03127-6 . ^ Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology . 10 (2): 43–57. doi : 10.1002/evan.1013 . S2CID 1665503 . ^ Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth" . USC Trojan Family Magazine . Archived from the original on 13 December 2010 . Retrieved 7 December 2010 . ^ Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex" . Society of Actuaries. Archived from the original on 1 July 2013. ^ "Life expectancy at birth, female (years)" . World Bank . 2018. Archived from the original on 24 January 2021 . Retrieved 13 October 2020 . ^ "Life expectancy at birth, male (years)" . World Bank . 2018. Archived from the original on 24 February 2021 . Retrieved 13 October 2020 . ^ Conceição P, et al. (2019). Human Development Report (PDF) . United Nations Development Programme. ISBN 978-92-1-126439-5 . Archived (PDF) from the original on 20 March 2021 . Retrieved 30 July 2022 . ^ "Human Development Report 2019" (PDF) . United Nations Development Programme . Archived from the original (PDF) on 22 April 2022 . Retrieved 30 July 2022 . ^ "The World Factbook" . U.S. Central Intelligence Agency. Archived from the original on 12 September 2009 . Retrieved 2 April 2005 . ^ "Chapter 1: Setting the Scene" (PDF) . UNFPA. 2012. Archived from the original (PDF) on 12 June 2013 . Retrieved 11 January 2013 . ^ Haenel H (1989). "Phylogenesis and nutrition". Die Nahrung . 33 (9): 867–887. PMID 2697806 . ^ Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable . pp. 264–265. Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods. ^ American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association . 103 (6): 748–765. doi : 10.1053/jada.2003.50142 . PMID 12778049 . ^ Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet" . American Journal of Physical Anthropology . 162 (S63): 84–109. doi : 10.1002/ajpa.23148 . PMID 28105723 . ^ Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century" . The American Journal of Clinical Nutrition . 81 (2): 341–354. doi : 10.1093/ajcn.81.2.341 . PMID 15699220 . ^ Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context" . The Proceedings of the Nutrition Society . 61 (4): 517–526. doi : 10.1079/PNS2002180 . PMID 12691181 . ^ John Carey (2023). "Unearthing the origins of agriculture" . Proceedings of the National Academy of Sciences . 120 (15): e2304407120. Bibcode : 2023PNAS..12004407C . doi : 10.1073/pnas.2304407120 . PMC 10104519 . PMID 37018195 . ^ Ayelet Shavit; Gonen Sharon (2023). "Can models of evolutionary transition clarify the debates over the Neolithic Revolution?" . Philosophical Transactions of the Royal Society B . 378 (1872). doi : 10.1098/rstb.2021.0413 . PMC 9869441 . PMID 36688395 . } ^ Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences" . The American Journal of Clinical Nutrition . 90 (3): 707S–711S. doi : 10.3945/ajcn.2009.27462B . PMID 19656837 . ^ Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology . 69 (5): 605–628. PMID 9299882 . ^ Gibbons A. "The Evolution of Diet" . National Geographic . Archived from the original on 18 August 2014 . Retrieved 18 April 2021 . ^ Ritchie H, Roser M (20 August 2017). "Diet Compositions" . Our World in Data . Archived from the original on 25 August 2021 . Retrieved 30 July 2022 . ^ Lieberson AD (2004). "How Long Can a Person Survive without Food?" . Scientific American . Archived from the original on 14 February 2019 . Retrieved 18 April 2021 . ^ Spector D (9 March 2018). "Here's how many days a person can survive without water" . Business Insider Australia . Archived from the original on 26 June 2014 . Retrieved 18 April 2021 . ^ Holmes J. "Losing 25,000 to Hunger Every Day" . United Nations . Archived from the original on 27 May 2020 . Retrieved 18 April 2021 . ^ Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic" . NPR . Archived from the original on 28 June 2021 . Retrieved 18 April 2021 . ^ Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet . 349 (9063): 1436–1442. doi : 10.1016/S0140-6736(96)07495-8 . PMID 9164317 . S2CID 2569153 . ^ Haslam DW, James WP (October 2005). "Obesity". Lancet . 366 (9492): 1197–1209. doi : 10.1016/S0140-6736(05)67483-1 . PMID 16198769 . S2CID 208791491 . ^ Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine . 30 (3): 415–444, vii. doi : 10.1016/j.ccm.2009.05.001 . PMID 19700042 . ^ de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology . 2 (1): 45–55. doi : 10.1016/j.ehb.2003.11.001 . PMID 15463992 . ^ O'Neil D. "Adapting to Climate Extremes" . Human Biological Adaptability . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status" . PLOS Genetics . 13 (9): e1006977. doi : 10.1371/journal.pgen.1006977 . PMC 5600404 . PMID 28873402 . ^ Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics . 35 (4): 311–313. doi : 10.1038/ng1263 . PMID 14634648 . S2CID 20415396 . ^ Hedrick PW (October 2011). "Population genetics of malaria resistance in humans" . Heredity . 107 (4): 283–304. doi : 10.1038/hdy.2011.16 . PMC 3182497 . PMID 21427751 . ^ Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria" . British Journal of Haematology . 141 (3): 276–286. doi : 10.1111/j.1365-2141.2008.07085.x . PMID 18410566 . S2CID 28191911 . ^ Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea" . Frontiers in Ecology and Evolution . 5 . doi : 10.3389/fevo.2017.00025 . hdl : 11858/00-001M-0000-002C-DD87-4 . ISSN 2296-701X . S2CID 34882477 . ^ Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads" . Cell . 173 (3): 569–580.e15. doi : 10.1016/j.cell.2018.03.054 . PMID 29677510 . ^ Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology . 45 (1): 105–08. doi : 10.1086/381006 . S2CID 224795768 . ^ Roberts D (2011). Fatal Invention . London & New York: The New Press. ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation" . Proceedings of the National Academy of Sciences of the United States of America . 107 (Supplement_2): 8962–8968. Bibcode : 2010PNAS..107.8962J . doi : 10.1073/pnas.0914628107 . PMC 3024016 . PMID 20445093 . ^ Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF) . Journal of Human Evolution . 39 (1): 57–106. doi : 10.1006/jhev.2000.0403 . PMID 10896812 . Archived from the original (PDF) on 14 January 2012. ^ Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R" . American Journal of Human Genetics . 66 (4): 1351–1361. doi : 10.1086/302863 . PMC 1288200 . PMID 10733465 . ^ Robin A (1991). Biological Perspectives on Human Pigmentation . Cambridge: Cambridge University Press. ^ "The Science Behind the Human Genome Project" . Human Genome Project . US Department of Energy. Archived from the original on 2 January 2013 . Retrieved 6 January 2013 . Almost all (99.9%) nucleotide bases are exactly the same in all people. ^ O'Neil D. "Ethnicity and Race: Overview" . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation" . Nature Genetics . 36 (11 Suppl): S17-20. doi : 10.1038/ng1455 . PMID 15507998 . ^ O'Neil D. "Models of Classification" . Modern Human Variation . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 . ^ Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . ^ Palmié S (May 2007). "Genomics, divination, 'racecraft' ". American Ethnologist . 34 (2): 205–222. doi : 10.1525/ae.2007.34.2.205 . ^ "Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations. ^ Goodman A. "Interview with Alan Goodman" . Race Power of and Illusion . PBS. Archived from the original on 29 October 2012 . Retrieved 6 January 2013 . ^ Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF) . New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012 . Retrieved 5 September 2013 . ^ Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo ^ O'Neil D. "Overview" . Modern Human Variation . Palomar College. Archived from the original on 5 November 2012 . Retrieved 6 January 2013 . ^ Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" . American Journal of Human Genetics . 66 (3): 979–988. doi : 10.1086/302825 . PMC 1288178 . PMID 10712212 . ^ "New Research Proves Single Origin Of Humans In Africa" . Science Daily . 19 July 2007. Archived from the original on 4 November 2011 . Retrieved 5 September 2011 . ^ Manica A, Amos W, Balloux F , Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation" . Nature . 448 (7151): 346–348. Bibcode : 2007Natur.448..346M . doi : 10.1038/nature05951 . PMC 1978547 . PMID 17637668 . ^ Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals" . Cell . 180 (4): 677–687.e16. doi : 10.1016/j.cell.2020.01.012 . PMID 32004458 . S2CID 210955842 . ^ Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations. ^ Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations" . Science Advances . 6 (7): eaax5097. Bibcode : 2020SciA....6.5097D . doi : 10.1126/sciadv.aax5097 . PMC 7015685 . PMID 32095519 . Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans. ^ Pierce BA (2012). Genetics: A Conceptual Approach . Macmillan. p. 75. ISBN 978-1-4292-3252-4 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology . Cambridge University Press. p. 74. ISBN 978-0-521-87948-4 . Retrieved 30 July 2022 . ^ Fusco G, Minelli A (10 October 2019). The Biology of Reproduction . Cambridge University Press. p. 304. ISBN 978-1-108-49985-9 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 . ^ Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution . 47 (4): 253–266. doi : 10.1016/j.jhevol.2004.07.004 . PMID 15454336 . ^ Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960–2002" (PDF) . Advance Data (347): 1–17. PMID 15544194 . Archived from the original (PDF) on 23 February 2011. ^ Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology . 66 (3): 254–262. doi : 10.1007/BF00235103 . hdl : 11375/22586 . PMID 8477683 . S2CID 206772211 . ^ Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity . Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi : 10.1007/978-3-319-70178-3_2 . ISBN 978-3-319-70177-6 . PMID 29224088 . ^ Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know" . International Journal of Women's Dermatology . 4 (3): 122–130. doi : 10.1016/j.ijwd.2018.03.002 . PMC 6116811 . PMID 30175213 . ^ Easter C. "Sex Linked" . National Human Genome Research Institute . Archived from the original on 14 April 2022 . Retrieved 18 April 2021 . ^ Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior . 27 (4): 283–296. doi : 10.1016/j.evolhumbehav.2005.11.003 . S2CID 32562654 . ^ "Gender, women, and health" . Reports from WHO 2002–2005 . Archived from the original on 25 June 2013. ^ Sax, Leonard (1 August 2002). "How common is lntersex? A response to Anne Fausto-Sterling" . The Journal of Sex Research . 39 (3): 174–178. doi : 10.1080/00224490209552139 . ISSN 0022-4499 . PMID 12476264 . S2CID 33795209 . ^ "3-D Brain Anatomy" . The Secret Life of the Brain . Public Broadcasting Service. Archived from the original on 5 September 2017 . Retrieved 3 April 2005 . ^ Stern P (22 June 2018). "The human prefrontal cortex is special" . Science . 360 (6395): 1311–1312. Bibcode : 2018Sci...360S1311S . doi : 10.1126/science.360.6395.1311-g . ISSN 0036-8075 . S2CID 149581944 . ^ Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?" . Journal of Intelligence . 2 (3): 119–121. doi : 10.3390/jintelligence2030119 . ISSN 2079-3200 . ^ "Humans not smarter than animals, just different, experts say" . phys.org . Archived from the original on 30 January 2021 . Retrieved 24 October 2020 . ^ Robson D. "We've got human intelligence all wrong" . www.bbc.com . Archived from the original on 31 January 2021 . Retrieved 24 October 2020 . ^ Owen J (26 February 2015). "Many Animals – Including Your Dog – May Have Horrible Short-Term Memories" . National Geographic News . Archived from the original on 19 April 2021 . Retrieved 6 September 2020 . ^ Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research" . American Journal of Physical Anthropology . 116 (S33): 3–24. doi : 10.1002/ajpa.20001 . PMC 2238342 . PMID 11786989 . ^ Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?" . ABC News (American) . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self" . New Scientist . Archived from the original on 18 February 2021 . Retrieved 22 April 2020 . ^ Beck J (2019). "Can We Really Know What Animals Are Thinking?" . Snopes . Archived from the original on 31 October 2021 . Retrieved 22 April 2020 . ^ Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies" . Sleep Medicine Reviews . 14 (4): 239–247. doi : 10.1016/j.smrv.2009.08.001 . PMC 2888649 . PMID 19896872 . ^ Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep" " . Science.howstuffworks.com. Archived from the original on 15 May 2012 . Retrieved 11 August 2012 . ^ Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience . 10 (11): 803–813. doi : 10.1038/nrn2716 . PMID 19794431 . S2CID 205505278 . ^ Empson J (2002). Sleep and dreaming (3rd ed.). New York: Palgrave/St. Martin's Press. ^ Lite J (29 July 2010). "How Can You Control Your Dreams?" . Scientific America . Archived from the original on 2 February 2015. ^ Domhoff W (2002). The scientific study of dreams . APA Press. ^ "Consciousness" . Merriam-Webster . Archived from the original on 7 September 2019 . Retrieved 4 June 2012 . ^ van Gulick R (2004). "Consciousness" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019 . Retrieved 30 July 2022 . ^ Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness . Wiley. ISBN 978-0-470-75145-9 . ^ Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy . Oxford University Press. ISBN 978-0-19-926479-7 . ^ Block N (June 1995). "On a confusion about a function of consciousness" . Behavioral and Brain Sciences . 18 (2): 227–247. doi : 10.1017/S0140525X00038474 . S2CID 246244859 . ^ Jaynes J (2000) [1976]. The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF) . Houghton Mifflin. ISBN 0-618-05707-2 . Archived from the original (PDF) on 7 August 2019 . Retrieved 25 October 2020 . ^ Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition . 12 (4): 717–731. doi : 10.1016/s1053-8100(03)00081-3 . PMID 14656513 . S2CID 10241157 . ^ Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness" . Stanford Encyclopedia of Philosophy . Archived from the original on 13 April 2021 . Retrieved 31 August 2014 . ^ Antony MV (2001). "Is consciousness ambiguous?". Journal of Consciousness Studies . 8 : 19–44. ^ "Cognition" . Lexico . Oxford University Press and Dictionary.com . Archived from the original on 8 July 2016 . Retrieved 6 May 2020 . ^ Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality . The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi : 10.1007/978-3-030-03633-1_14 . ISBN 978-3-030-03633-1 . S2CID 189379814 . ^ "American Psychological Association (2013). Glossary of psychological terms" . Apa.org. Archived from the original on 8 July 2014 . Retrieved 13 August 2014 . ^ "Developmental Psychology Studies Human Development Across the Lifespan" . www.apa.org . Archived from the original on 9 July 2014 . Retrieved 28 August 2017 . ^ Burman E (2017). Deconstructing Developmental Psychology . New York: Routledge. ISBN 978-1-138-84695-1 . ^ Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology : 307–314. doi : 10.1016/B0-12-657410-3/00510-9 . ISBN 978-0-12-657410-4 . ^ McLeod S (20 March 2020). "Maslow's Hierarchy of Needs" . Simplypsychology.org . Simply Scholar Limited. Archived from the original on 8 November 2018 . Retrieved 4 April 2020 . Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up. ^ Heckhausen J, Heckhausen H (28 March 2018). "Motivation and Action: Introduction and Overview". Motivation and Action . Introduction and Overview: Springer, Cham. p. 1. doi : 10.1007/978-3-319-65094-4_1 . ISBN 978-3-319-65093-7 . ^ Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews . 26 (2–3): 83–86. doi : 10.1016/s0165-0173(97)00064-7 . PMID 9651488 . S2CID 8504450 . ^ Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions . New York: Oxford University Press. pp. 291–293. ISBN 978-0-19-508944-8 . Emotional processing, but not emotions, can occur unconsciously. ^ Cabanac M (2002). "What is emotion?". Behavioural Processes . 60 (2): 69–83. doi : 10.1016/S0376-6357(02)00078-5 . PMID 12426062 . S2CID 24365776 . Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure) ^ Scirst DL (2011). Psychology Second Edition . New York: Worth Publishers. p. 310 . ISBN 978-1-4292-3719-2 . ^ Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality . 67 (2): 331–371. doi : 10.1111/1467-6494.00058 . PMID 10202807 . ^ Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory" . Frontiers in Psychology . 8 : 1454. doi : 10.3389/fpsyg.2017.01454 . PMC 5573739 . PMID 28883804 . ^ Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology . Oxford University Press. Archived from the original on 29 January 2021 . Retrieved 30 July 2022 . ^ Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals" . Industrial Psychiatry Journal . 24 (1): 54–58. doi : 10.4103/0972-6748.160934 . PMC 4525433 . PMID 26257484 . ^ Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions" . The American Psychologist . 56 (3): 218–226. doi : 10.1037/0003-066X.56.3.218 . PMC 3122271 . PMID 11315248 . ^ Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica . 90 (3): 387–411. doi : 10.11612/resphil.2013.90.3.5 . ^ Haybron DM (13 April 2014). "Happiness and Its Discontents" . The Opinion Pages . The New York Times. Archived from the original on 12 October 2018 . Retrieved 30 July 2022 . I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life. ^ Graham MC (2014). Facts of Life: ten issues of contentment . Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5 . ^ "Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy" . ScienceDaily . American Psychological Association . 14 August 2017. Archived from the original on 11 November 2020 . Retrieved 25 October 2020 . ^ Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality . Jones & Bartlett Publishers . pp. 4–10. ISBN 978-1-284-08154-1 . Retrieved 21 June 2017 . Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings. ^ Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives . Taylor & Francis . pp. 32–42. ISBN 978-0-7890-2671-2 . ^ Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology . 3 (4): 85–89. doi : 10.1097/01.XHA.0000432482.01760.b0 . S2CID 147235090 . ^ "Sexual orientation, homosexuality and bisexuality" . American Psychological Association . Archived from the original on 8 August 2013 . Retrieved 10 August 2013 . ^ Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science" . Psychological Science in the Public Interest . 17 (2): 45–101. doi : 10.1177/1529100616637616 . PMID 27113562 . ^ LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation . Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6 . Retrieved 30 July 2022 . ^ Balthazart J (2012). The Biology of Homosexuality . Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0 . Retrieved 30 July 2022 . ^ Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York: Basic Books. ISBN 978-0-465-00802-5 . ^ Fromm E (2000). The art of loving . New York: Harper Perennial. ISBN 978-0-06-095828-2 . ^ "Love, Actually: The science behind lust, attraction, and companionship" . Science in the News . 14 February 2017. Archived from the original on 28 October 2020 . Retrieved 25 October 2020 . ^ "What are the top 200 most spoken languages?" . Ethnologue: Languages of the World . 2020. Archived from the original on 12 January 2013 . Retrieved 30 July 2022 . ^ World . The World Factbook (Report). Central Intelligence Agency . Archived from the original on 26 January 2021 . Retrieved 15 November 2021 . ^ "The Changing Global Religious Landscape" . Pew Research Center. 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 30 July 2022 . ^ Ord T (2020). The Precipice: Existential Risk and the Future of Humanity . New York: Hachette Books. ISBN 978-0-316-48489-3 . Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence... ^ Goldman JG (2012). "Pay attention… time for lessons at animal school" . bbc.com . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 . ^ Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding" . Science Advances . 4 (11): eaar8334. Bibcode : 2018SciA....4.8334W . doi : 10.1126/sciadv.aar8334 . PMC 6248967 . PMID 30474053 . ^ Johnson-Frey SH (July 2003). "What's so special about human tool use?" . Neuron . 39 (2): 201–204. doi : 10.1016/S0896-6273(03)00424-0 . PMID 12873378 . S2CID 18437970 . ^ Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology . 19 (1): 27–33. doi : 10.1016/j.conb.2009.02.003 . PMID 19328675 . S2CID 18277620 . In short, the evidence to date that animals have an understanding of folk physics is at best mixed. ^ Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To" . National Geographic News . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education" . Procedia - Social and Behavioral Sciences . The Proceedings of 6th World Conference on educational Sciences. 191 : 2565–2567. doi : 10.1016/j.sbspro.2015.04.690 . ISSN 1877-0428 . ^ McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species" . The Guardian . Archived from the original on 5 February 2021 . Retrieved 22 April 2020 . ^ Nicholls H (29 June 2015). "Babblers speak to the origin of language" . The Guardian . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 . ^ Dasgupta S (2015). "Can any animals talk and use language like humans?" . bbc.com . Archived from the original on 2 May 2020 . Retrieved 22 April 2020 . Most animals are not vocal learners. ^ Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?" . Royal Society. Archived from the original on 18 January 2021 . Retrieved 24 October 2020 . ^ Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?" . BMC Biology . 15 (1): 64. doi : 10.1186/s12915-017-0405-3 . PMC 5525259 . PMID 28738867 . ^ Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist . 208 (2789): ii–iii. Bibcode : 2010NewSc.208D...2F . doi : 10.1016/S0262-4079(10)62961-2 . ISSN 0262-4079 . ^ Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments . London: Palgrave Macmillan UK. pp. 229–255. doi : 10.1057/978-1-137-58746-6_7 . ISBN 978-1-137-58746-6 . ^ "Culture | United Nations For Indigenous Peoples" . www.un.org . 5 June 2015. Archived from the original on 26 November 2020 . Retrieved 24 October 2020 . ^ Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World . New York: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1 . ^ Mavrody S (2013). Visual Art Forms: Traditional to Digital . Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9 . Retrieved 30 July 2022 . ^ "Types of Literary Arts and Their Understanding – bookfestivalscotland.com" . Bookfestival Scotland . 2020. Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ "Bachelor of Performing Arts" (PDF) . University of Otago . Archived (PDF) from the original on 14 December 2021 . Retrieved 30 July 2022 . ^ Brown S (24 October 2018). "Toward a Unification of the Arts" . Frontiers in Psychology . 9 : 1938. doi : 10.3389/fpsyg.2018.01938 . ISSN 1664-1078 . PMC 6207603 . PMID 30405470 . ^ "Culinary arts – How cooking can be an art" . Northern Contemporary Art . 21 October 2019. Archived from the original on 11 May 2021 . Retrieved 5 May 2021 . ^ Smuts A (1 January 2005). "Are Video Games Art?" . Contemporary Aesthetics (Journal Archive) . 3 (1). Archived from the original on 29 May 2022 . Retrieved 30 July 2022 . ^ Cameron IA, Pimlott N (September 2015). "Art of medicine" . Canadian Family Physician . 61 (9): 739–740. PMC 4569099 . PMID 26371092 . ^ Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy . 25 (4): 458–470. doi : 10.1080/10286632.2017.1311328 . ISSN 1028-6632 . S2CID 151443044 . ^ Morriss-Kay GM (February 2010). "The evolution of human artistic creativity" . Journal of Anatomy . 216 (2): 158–176. doi : 10.1111/j.1469-7580.2009.01160.x . PMC 2815939 . PMID 19900185 . ^ Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature . 518 (7538): 228–231. Bibcode : 2015Natur.518..228J . doi : 10.1038/nature13962 . PMID 25470048 . S2CID 4461751 . ^ St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave" . The New York Times . Archived from the original on 14 April 2020 . Retrieved 20 September 2018 . ^ Radford T (16 April 2004). "World's oldest jewellery found in cave" . The Guardian . ISSN 0261-3077 . Archived from the original on 12 February 2021 . Retrieved 23 September 2020 . ^ Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches . Amsterdam: Valiz. pp. 241–263. ^ Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia . 92 (92): 147–177. doi : 10.4436/JASS.92008 (inactive 2024-03-20). PMID 25020016 . {{ cite journal }} : CS1 maint: DOI inactive as of March 2024 ( link ) ^ Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness" (PDF) . NeuroImage . 103 : 55–64. doi : 10.1016/j.neuroimage.2014.09.009 . PMID 25224999 . S2CID 4727529 . ^ Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences . 1337 (1): 140–146. Bibcode : 2015NYASA1337..140K . doi : 10.1111/nyas.12632 . PMID 25773628 . S2CID 206224849 . ^ Chow D (22 March 2010). "Why Do Humans Dance?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 21 September 2020 . ^ Krakauer J (26 September 2008). "Why do we like to dance – And move to the beat?" . Scientific American . Archived from the original on 28 February 2021 . Retrieved 21 September 2020 . ^ Prior KS (21 June 2013). "How Reading Makes Us More Human" . The Atlantic . Archived from the original on 29 January 2021 . Retrieved 23 September 2020 . ^ Puchner M. "How stories have shaped the world" . www.bbc.com . Archived from the original on 5 January 2021 . Retrieved 23 September 2020 . ^ Dalley, Stephanie , ed. (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5 . ^ Hernadi P (2001). "Literature and Evolution" . SubStance . 30 (1/2): 55–71. doi : 10.2307/3685504 . ISSN 0049-2426 . JSTOR 3685504 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run" . The Guardian (U.S. ed.). New York. Archived from the original on 18 June 2022 . Retrieved 30 July 2022 . ^ Clark JD; de Heinzelin J ; Schick KD ; Hart WK; White TD ; WoldeGabriel G; Walter RC; Suwa G ; Asfaw B ; Vrba E ; H.-Selassie Y (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science . 264 (5167): 1907–1910. Bibcode : 1994Sci...264.1907C . doi : 10.1126/science.8009220 . PMID 8009220 . ^ Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use" . livescience.com . Archived from the original on 4 October 2020 . Retrieved 9 October 2020 . ^ Orban GA, Caruana F (2014). "The neural basis of human tool use" . Frontiers in Psychology . 5 : 310. doi : 10.3389/fpsyg.2014.00310 . PMC 3988392 . PMID 24782809 . ^ Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa" . Proceedings of the National Academy of Sciences of the United States of America . 109 (20): E1215-20. doi : 10.1073/pnas.1117620109 . PMC 3356665 . PMID 22474385 . ^ Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1696): 20150164. doi : 10.1098/rstb.2015.0164 . PMC 4874402 . PMID 27216521 . ^ Damiano J (2018). "Neolithic Era Tools: Inventing a New Age" . MagellanTV . Archived from the original on 5 January 2021 . Retrieved 9 October 2020 . ^ Deng Y, Wang P (2011). Ancient Chinese inventions . Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6 . OCLC 671710733 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Schifman J (9 July 2018). "The Entire History of Steel" . Popular Mechanics . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Wilkinson, Freddie (9 January 2020). "Industrial Revolution and Technology" . National Geographic Society . Archived from the original on 30 September 2020 . Retrieved 9 October 2020 . ^ Roser, Max ; Ritchie, Hannah (11 May 2013). "Technological Progress" . Our World in Data . Archived from the original on 10 September 2021 . Retrieved 30 July 2022 . ^ Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel" . The Atlantic . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 . ^ Idinopulos TA (1998). "What Is Religion?" . CrossCurrents . 48 (3): 366–380. ISSN 0011-1953 . JSTOR 24460821 . Archived from the original on 13 October 2020 . Retrieved 30 July 2022 . ^ Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology . 54 (1): 377–402. doi : 10.1146/annurev.psych.54.101601.145024 . PMID 12171998 . ^ King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?" . The Atlantic . Archived from the original on 20 January 2021 . Retrieved 8 October 2020 . ^ Ball P (2015). "Complex societies evolved without belief in all-powerful deity" . Nature News . doi : 10.1038/nature.2015.17040 . S2CID 183474917 . Archived from the original on 16 May 2021 . Retrieved 30 July 2022 . ^ Culotta E (November 2009). "Origins. On the origin of religion". Science . 326 (5954): 784–787. Bibcode : 2009Sci...326..784C . doi : 10.1126/science.326_784 . PMID 19892955 . ^ Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation" . Evolution and Human Behavior . 32 (1): 41–49. doi : 10.1016/j.evolhumbehav.2010.07.008 . ISSN 1090-5138 . Archived from the original on 15 October 2020 . Retrieved 30 July 2022 . ^ Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA – Journal of Death and Dying . 41 (1): 5–22. doi : 10.2190/Q21C-5VED-GYW6-W091 . ISSN 0030-2228 . S2CID 145686249 . ^ McKay R, Whitehouse H (March 2015). "Religion and morality" . Psychological Bulletin . 141 (2): 447–473. doi : 10.1037/a0038455 . PMC 4345965 . PMID 25528346 . ^ Bernhard Nitsche; Marcus Schmücker, eds. (2023). God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality . De Gruyter . doi : 10.1515/9783110698343 . ISBN 978-3-11-069834-3 . ^ Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique" . Journal of Religion and Health (Submitted manuscript). 47 (2): 134–163. doi : 10.1007/s10943-008-9165-2 . PMC 8823950 . PMID 19105008 . S2CID 25349208 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular" . The Guardian . ISSN 0261-3077 . Archived from the original on 1 March 2021 . Retrieved 8 October 2020 . ^ Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe" . Pew Research Center . Archived from the original on 24 November 2019 . Retrieved 8 October 2020 . ^ "The Changing Global Religious Landscape" . Pew Research Center's Religion & Public Life Project . 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 8 October 2020 . ^ Di Christina, Mariette (September 2018). "A Very Human Story: Why Our Species Is Special" . Scientific American . Archived from the original on 24 November 2020 . Retrieved 27 September 2020 . ^ Andersen H , Hepburn B (2020). "Scientific Method" . In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Lo Presti R (2014). "History of science: The first scientist" . Nature . 512 (7514): 250–251. Bibcode : 2014Natur.512..250L . doi : 10.1038/512250a . ISSN 1476-4687 . S2CID 4394696 . ^ Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn . Springer. p. 1. ISBN 978-3-642-18904-3 . OCLC 883392276 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Needham, J ; Wang Ling (1954). Science and civilisation in China . Cambridge University Press. p. 111. ISBN 0-521-05799-X . OCLC 779676 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6 . OCLC 615209781 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017 . Retrieved 3 July 2017 . ^ Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition . Cambridge University Press. pp. 209–210. ISBN 978-1-107-01116-8 . ^ "Branches of Science" (PDF) . University of Chicago . Archived from the original (PDF) on 23 April 2017 . Retrieved 26 June 2017 . ^ "What is Philosophy?" . Department of Philosophy . Florida State University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ "Philosophy" . Definition, Systems, Fields, Schools, & Biographies . Encyclopedia Britannica. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 . ^ Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day" . Philosophy and Phenomenological Research . 7 (3): 461. doi : 10.2307/2102800 . JSTOR 2102800 . Archived from the original on 31 March 2022 . Retrieved 30 July 2022 . ^ Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?" . ieet.org . Archived from the original on 4 March 2021 . Retrieved 8 August 2020 . ^ Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?" . European Journal of Information Systems . 27 (3): 263–277. doi : 10.1080/0960085X.2018.1470776 . hdl : 2086/16128 . ISSN 0960-085X . S2CID 64796132 . ^ Schizzerotto A. "Social Stratification" (PDF) . University of Trento . Archived from the original (PDF) on 20 March 2018 . Retrieved 3 July 2017 . ^ Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution . Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9 . OCLC 1082411117 . ^ "Social Role Theory of Sex Differences and Similarities : A Current Appraisal" . The Developmental Social Psychology of Gender . Psychology Press. 2000. pp. 137–188. doi : 10.4324/9781410605245-12 . ISBN 978-1-4106-0524-5 . Archived from the original on 30 April 2021 . Retrieved 10 June 2022 . ^ Blackstone, Amy (2003). "Gender Roles and Society" . In Miller, Julia R.; Lerner, Richard M.; Schiamberg, Lawrence B. (eds.). Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments . Sociology School Faculty Scholarship. Santa barbara, CA: ABC-CLIO. p. 335. Archived from the original on 16 May 2022 . Retrieved 30 July 2022 . ^ Nadal, Kevin L. (2017). The SAGE Encyclopedia of Psychology and Gender . SAGE Publications. p. 401. ISBN 978-1483384276 . Most cultures currently construct their societies based on the understanding of gender binary – the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization. ^ Herdt, Gilbert (2020). "Third Sexes and Third Genders". Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . Princeton, NJ: Princeton University Press. pp. 21–83. ISBN 978-1-942130-52-9 . Retrieved 30 July 2022 . ^ Trumbach, Randolph (1994). "London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture". In Herdt, Gilbert (ed.). Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . New York: Zone (MIT). pp. 111–136. ISBN 978-0-942299-82-3 . ^ Graham, Sharyn (April–June 2001). "Sulawesi's fifth gender" . Inside Indonesia . Archived from the original on 26 November 2014. ^ Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John ; Nieder, Timo O.; T'Sjoen, Guy (2016). "Non-binary or genderqueer genders" . International Review of Psychiatry . 28 (1): 95–102. doi : 10.3109/09540261.2015.1106446 . hdl : 1854/LU-7279758 . PMID 26753630 . S2CID 29985722 . Archived from the original on 26 June 2019 . Retrieved 9 June 2019 . ^ Ananthaswamy, Anil; Douglas, Kate. "The origins of sexism: How men came to rule 12,000 years ago" . New Scientist . Retrieved 7 March 2023 . ^ "What do we mean by "sex" and "gender"?" . World Health Organization . Archived from the original on 30 January 2017 . Retrieved 26 November 2015 . ^ Alters S, Schiff W (2009). Essential Concepts for Healthy Living . Jones & Bartlett Publishers . p. 143. ISBN 978-0-7637-5641-3 . Retrieved 3 January 2018 . ^ Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy . 21 (3): 416–438. doi : 10.1093/oxrep/gri024 . ^ Dobres, Marcia-Anne (27 November 2020). "Gender in the Earliest Human Societies" . In Meade, Teresa A.; Wiesner-Hanks, Merry E. (eds.). A Companion to Global Gender History (1 ed.). Wiley. pp. 183–204. doi : 10.1002/9781119535812.ch11 . ISBN 978-1-119-53580-5 . S2CID 229399965 . Archived from the original on 10 June 2022 . Retrieved 10 June 2022 . ^ "The Nature of Kinship: Overview" . www2.palomar.edu . Archived from the original on 3 December 2020 . Retrieved 24 October 2020 . ^ Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition" . Proceedings of the National Academy of Sciences of the United States of America . 117 (5): 2378–2384. Bibcode : 2020PNAS..117.2378I . doi : 10.1073/pnas.1917716117 . PMC 7007516 . PMID 31964846 . ^ Chandra, Kanchan (2012). Constructivist theories of ethnic politics . Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7 . OCLC 829678440 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 . ^ People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389. In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of 'us' and 'them.' In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population. ^ Blackmore E (22 February 2019). "Race and ethnicity: How are they different?" . Culture . Archived from the original on 22 October 2020 . Retrieved 24 October 2020 . ^ Chandra K (2006). "What is Ethnic Identity and Does It Matter?" . Annual Review of Political Science . 9 (1): 397–424. doi : 10.1146/annurev.polisci.9.062404.170715 . ISSN 1094-2939 . ^ Smith AD (1999). Myths and Memories of the Nation . Oxford University Press. pp. 4–7. ^ Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism . 13 (1): 19–35. doi : 10.1111/j.1469-8129.2007.00271.x . ^ Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism . London: Sage. p. 171. ISBN 978-1-4129-0101-7 . ^ Christian D (2004). Maps of Time . University of California Press. ISBN 978-0-520-24476-4 . ^ Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?" . SAPIENS . Archived from the original on 7 August 2020 . Retrieved 24 October 2020 . ^ Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit" . Proceedings of the National Academy of Sciences of the United States of America . 115 (19): E4532–E4540. Bibcode : 2018PNAS..115E4532Z . doi : 10.1073/pnas.1708960115 . PMC 5948950 . PMID 29674447 . S2CID 4993139 . ^ Melina R (14 February 2011). "What Are the Different Types of Governments?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 24 October 2020 . ^ "Democracy Index 2021: less than half the world lives in a democracy" . The Economist Democracy Index . Economist Intelligence Unit . February 10, 2022. ^ Jeannie Evers (23 December 2012). "international organization" . National Geographic Society . Archived from the original on 27 April 2017 . Retrieved 24 October 2020 . ^ Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization . 58 (1): 1–29. doi : 10.1016/j.jebo.2004.03.009 . ISSN 0167-2681 . ^ Gibbons J (11 August 2015). "Why did Neanderthals go extinct?" . Smithsonian Insider . Archived from the original on 12 November 2020 . Retrieved 11 October 2020 . ^ University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?" . www.newswise.com . Archived from the original on 1 February 2021 . Retrieved 11 October 2020 . ^ Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years" . inews.co.uk . Archived from the original on 23 January 2021 . Retrieved 11 October 2020 . ^ Henriques M. "How spices changed the ancient world" . www.bbc.com . Archived from the original on 25 January 2021 . Retrieved 11 October 2020 . ^ Strauss IE (26 February 2016). "The Myth of the Barter Economy" . The Atlantic . Archived from the original on 15 February 2021 . Retrieved 11 October 2020 . ^ "The History of Money" . www.pbs.org . 26 October 1996. Archived from the original on 29 November 2020 . Retrieved 11 October 2020 . ^ "Why do we need economists and the study of economics?" . Federal Reserve Bank of San Francisco . July 2000. Archived from the original on 12 November 2020 . Retrieved 23 October 2020 . ^ Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong" . New Scientist . Archived from the original on 3 February 2021 . Retrieved 24 October 2020 . ^ Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates" . The Atlantic . Archived from the original on 7 May 2021 . Retrieved 7 May 2021 . ^ Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature . 538 (7624): 233–237. Bibcode : 2016Natur.538..233G . doi : 10.1038/nature19758 . PMID 27680701 . S2CID 4454927 . ^ Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF) . Nature . 538 (7624): 180–181. Bibcode : 2016Natur.538..180P . doi : 10.1038/nature19474 . PMID 27680700 . S2CID 4459560 . Archived (PDF) from the original on 20 May 2022 . Retrieved 30 July 2022 . ^ Ferguson RB (1 September 2018). "War Is Not Part of Human Nature" . Scientific American . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 . ^ Ferguson N (September–October 2006). "The Next War of the World" . Foreign Affairs . Archived from the original on 25 April 2022 . Retrieved 30 July 2022 . ^ Beauchamp, Zack (June 23, 2015). "600 years of war and peace, in one amazing chart" . Vox .
Groves CP (2005). Wilson DE , Reeder DM (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Baltimore: Johns Hopkins University Press. ISBN 0-801-88221-4 . OCLC 62265494 .
Spamer EE (29 January 1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758". Proceedings of the Academy of Natural Sciences . 149 (1): 109–114. JSTOR 4065043 .
"Homo" . Dictionary.com Unabridged (v 1.1) . Random House. 23 September 2008. Archived from the original on 27 September 2008.
Barras, Colin (11 January 2016). "We don't know which species should be classed as 'human' " . BBC . Archived from the original on 26 August 2021 . Retrieved 31 March 2021 .
Spamer EE (1999). "Know Thyself: Responsible Science and the Lectotype of Homo sapiens Linnaeus, 1758" . Proceedings of the Academy of Natural Sciences of Philadelphia . 149 : 109–114. ISSN 0097-3157 . JSTOR 4065043 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 .
"Man" . Merriam-Webster Dictionary . Archived from the original on 22 September 2017 . Retrieved 14 September 2017 . Definition 2: a man belonging to a particular category (as by birth, residence, membership, or occupation) – usually used in combination
"Thesaurus results for human" . Merriam-Webster Dictionary . Archived from the original on 28 June 2022 . Retrieved 21 May 2022 .
"Misconceptions about evolution – Understanding Evolution" . University of California, Berkeley . 19 September 2021. Archived from the original on 6 June 2022 . Retrieved 21 May 2022 .
"Concept of Personhood" . University of Missouri School of Medicine . Archived from the original on 4 March 2021 . Retrieved 4 July 2021 .
Tuttle RH (4 October 2018). "Hominoidea: conceptual history" . In Trevathan W, Cartmill M, Dufour D, Larsen C (eds.). International Encyclopedia of Biological Anthropology . Hoboken , New Jersey , United States : John Wiley & Sons, Inc. pp. 1–2. doi : 10.1002/9781118584538.ieba0246 . ISBN 978-1-118-58442-2 . S2CID 240125199 . Retrieved 26 May 2021 .
Goodman M, Tagle DA, Fitch DH, Bailey W, Czelusniak J, Koop BF, et al. (March 1990). "Primate evolution at the DNA level and a classification of hominoids". Journal of Molecular Evolution . 30 (3): 260–266. Bibcode : 1990JMolE..30..260G . doi : 10.1007/BF02099995 . PMID 2109087 . S2CID 2112935 .
Ruvolo M (March 1997). "Molecular phylogeny of the hominoids: inferences from multiple independent DNA sequence data sets" . Molecular Biology and Evolution . 14 (3): 248–265. doi : 10.1093/oxfordjournals.molbev.a025761 . PMID 9066793 .
MacAndrew A. "Human Chromosome 2 is a fusion of two ancestral chromosomes" . Evolution pages . Archived from the original on 9 August 2011 . Retrieved 18 May 2006 .
McNulty, Kieran P. (2016). "Hominin Taxonomy and Phylogeny: What's In A Name?" . Nature Education Knowledge . Archived from the original on 10 January 2016 . Retrieved 11 June 2022 .
Strait DS (September 2010). "The Evolutionary History of the Australopiths" . Evolution: Education and Outreach . 3 (3): 341–352. doi : 10.1007/s12052-010-0249-6 . ISSN 1936-6434 . S2CID 31979188 .
Dunsworth HM (September 2010). "Origin of the Genus Homo" . Evolution: Education and Outreach . 3 (3): 353–366. doi : 10.1007/s12052-010-0247-8 . ISSN 1936-6434 . S2CID 43116946 .
Kimbel WH, Villmoare B (July 2016). "From Australopithecus to Homo: the transition that wasn't" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1698): 20150248. doi : 10.1098/rstb.2015.0248 . PMC 4920303 . PMID 27298460 . S2CID 20267830 .
Villmoare B, Kimbel WH, Seyoum C, Campisano CJ, DiMaggio EN, Rowan J, et al. (March 2015). "Paleoanthropology. Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia" . Science . 347 (6228): 1352–1355. Bibcode : 2015Sci...347.1352V . doi : 10.1126/science.aaa1343 . PMID 25739410 .
Zhu Z, Dennell R, Huang W, Wu Y, Qiu S, Yang S, et al. (July 2018). "Hominin occupation of the Chinese Loess Plateau since about 2.1 million years ago". Nature . 559 (7715): 608–612. Bibcode : 2018Natur.559..608Z . doi : 10.1038/s41586-018-0299-4 . PMID 29995848 . S2CID 49670311 .
Hublin JJ, Ben-Ncer A, Bailey SE, Freidline SE, Neubauer S, Skinner MM, et al. (June 2017). "New fossils from Jebel Irhoud, Morocco and the pan-African origin of Homo sapiens" (PDF) . Nature . 546 (7657): 289–292. Bibcode : 2017Natur.546..289H . doi : 10.1038/nature22336 . PMID 28593953 . S2CID 256771372 . Archived (PDF) from the original on 8 January 2020 . Retrieved 30 July 2022 .
"Out of Africa Revisited". Science (This Week in Science ). 308 (5724): 921. 13 May 2005. doi : 10.1126/science.308.5724.921g . ISSN 0036-8075 . S2CID 220100436 .
Stringer C (June 2003). "Human evolution: Out of Ethiopia". Nature . 423 (6941): 692–693, 695. Bibcode : 2003Natur.423..692S . doi : 10.1038/423692a . PMID 12802315 . S2CID 26693109 .
Johanson D (May 2001). "Origins of Modern Humans: Multiregional or Out of Africa?" . actionbioscience . Washington, DC: American Institute of Biological Sciences . Archived from the original on 17 June 2021 . Retrieved 23 November 2009 .
Marean, Curtis; et al. (2007). "Early human use of marine resources and pigment in South Africa during the Middle Pleistocene" (PDF) . Nature . 449 (7164): 905–908. Bibcode : 2007Natur.449..905M . doi : 10.1038/nature06204 . PMID 17943129 . S2CID 4387442 . Archived (PDF) from the original on 2023-05-25 . Retrieved 2023-01-07 .
Brooks AS, Yellen JE, Potts R, Behrensmeyer AK, Deino AL, Leslie DE, Ambrose SH, Ferguson JR, d'Errico F, Zipkin AM, Whittaker S, Post J, Veatch EG, Foecke K, Clark JB (2018). "Long-distance stone transport and pigment use in the earliest Middle Stone Age" . Science . 360 (6384): 90–94. Bibcode : 2018Sci...360...90B . doi : 10.1126/science.aao2646 . PMID 29545508 .
Posth C, Renaud G, Mittnik A, Drucker DG, Rougier H, Cupillard C, et al. (March 2016). "Pleistocene Mitochondrial Genomes Suggest a Single Major Dispersal of Non-Africans and a Late Glacial Population Turnover in Europe". Current Biology . 26 (6): 827–833. Bibcode : 2016CBio...26..827P . doi : 10.1016/j.cub.2016.01.037 . hdl : 2440/114930 . PMID 26853362 . S2CID 140098861 .
Karmin M, Saag L, Vicente M, Wilson Sayres MA, Järve M, Talas UG, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture" . Genome Research . 25 (4): 459–466. doi : 10.1101/gr.186684.114 . PMC 4381518 . PMID 25770088 .
Armitage SJ, Jasim SA, Marks AE, Parker AG, Usik VI, Uerpmann HP (January 2011). "The southern route "out of Africa": evidence for an early expansion of modern humans into Arabia" . Science . 331 (6016): 453–456. Bibcode : 2011Sci...331..453A . doi : 10.1126/science.1199113 . PMID 21273486 . S2CID 20296624 . Archived from the original on 27 April 2011 . Retrieved 1 May 2011 .
Rincon P (27 January 2011). "Humans 'left Africa much earlier' " . BBC News . Archived from the original on 9 August 2012.
Clarkson C, Jacobs Z, Marwick B, Fullagar R, Wallis L, Smith M, et al. (July 2017). "Human occupation of northern Australia by 65,000 years ago". Nature . 547 (7663): 306–310. Bibcode : 2017Natur.547..306C . doi : 10.1038/nature22968 . hdl : 2440/107043 . PMID 28726833 . S2CID 205257212 .
Lowe DJ (2008). "Polynesian settlement of New Zealand and the impacts of volcanism on early Maori society: an update" (PDF) . University of Waikato . Archived (PDF) from the original on 22 May 2010 . Retrieved 29 April 2010 .
Appenzeller T (May 2012). "Human migrations: Eastern odyssey" . Nature . 485 (7396): 24–26. Bibcode : 2012Natur.485...24A . doi : 10.1038/485024a . PMID 22552074 .
Reich D , Green RE, Kircher M, Krause J, Patterson N, Durand EY, et al. (December 2010). "Genetic history of an archaic hominin group from Denisova Cave in Siberia" . Nature . 468 (7327): 1053–1060. Bibcode : 2010Natur.468.1053R . doi : 10.1038/nature09710 . hdl : 10230/25596 . PMC 4306417 . PMID 21179161 .
Hammer MF (May 2013). "Human Hybrids" (PDF) . Scientific American . 308 (5): 66–71. Bibcode : 2013SciAm.308e..66H . doi : 10.1038/scientificamerican0513-66 . PMID 23627222 . Archived from the original (PDF) on 24 August 2018.
Yong E (July 2011). "Mosaic humans, the hybrid species" . New Scientist . 211 (2823): 34–38. Bibcode : 2011NewSc.211...34Y . doi : 10.1016/S0262-4079(11)61839-3 .
Ackermann RR, Mackay A, Arnold ML (October 2015). "The Hybrid Origin of "Modern" Humans". Evolutionary Biology . 43 (1): 1–11. doi : 10.1007/s11692-015-9348-1 . S2CID 14329491 .
Noonan JP (May 2010). "Neanderthal genomics and the evolution of modern humans" . Genome Research . 20 (5): 547–553. doi : 10.1101/gr.076000.108 . PMC 2860157 . PMID 20439435 .
Abi-Rached L, Jobin MJ, Kulkarni S, McWhinnie A, Dalva K, Gragert L, et al. (October 2011). "The shaping of modern human immune systems by multiregional admixture with archaic humans" . Science . 334 (6052): 89–94. Bibcode : 2011Sci...334...89A . doi : 10.1126/science.1209202 . PMC 3677943 . PMID 21868630 .
Sandel, Aaron A. (30 July 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness" . American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 . Archived from the original on 22 July 2023 . Retrieved 22 July 2023 .
Little, Michael A.; Blumler, Mark A. (2015). "Hunter-Gatherers" . In Muehlenbein, Michael P. (ed.). Basics in Human Evolution . Boston: Academic Press. pp. 323–335. ISBN 978-0-12-802652-6 . Archived from the original on 3 July 2022 . Retrieved 30 July 2022 .
Scarre, Chris (2018). "The world transformed: from foragers and farmers to states and empires". In Scarre, Chris (ed.). The Human Past: World Prehistory and the Development of Human Societies (4th ed.). London: Thames & Hudson . pp. 174–197. ISBN 978-0-500-29335-5 .
Colledge S, Conolly J, Dobney K, Manning K, Shennan S (2013). Origins and Spread of Domestic Animals in Southwest Asia and Europe . Walnut Creek, CA: Left Coast Press. pp. 13–17. ISBN 978-1-61132-324-5 . OCLC 855969933 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Scanes CG (January 2018). "The Neolithic Revolution, Animal Domestication, and Early Forms of Animal Agriculture". In Scanes CG, Toukhsati SR (eds.). Animals and Human Society . Elsevier. pp. 103–131. doi : 10.1016/B978-0-12-805247-1.00006-X . ISBN 978-0-12-805247-1 .
He K, Lu H, Zhang J, Wang C, Huan X (7 June 2017). "Prehistoric evolution of the dualistic structure mixed rice and millet farming in China" . The Holocene . 27 (12): 1885–1898. Bibcode : 2017Holoc..27.1885H . doi : 10.1177/0959683617708455 . S2CID 133660098 . Archived from the original on 20 November 2021 . Retrieved 30 July 2022 .
Lu H, Zhang J, Liu KB, Wu N, Li Y, Zhou K, et al. (May 2009). "Earliest domestication of common millet (Panicum miliaceum) in East Asia extended to 10,000 years ago" . Proceedings of the National Academy of Sciences of the United States of America . 106 (18): 7367–7372. Bibcode : 2009PNAS..106.7367L . doi : 10.1073/pnas.0900158106 . PMC 2678631 . PMID 19383791 .
Denham TP, Haberle SG, Lentfer C, Fullagar R, Field J, Therin M, et al. (July 2003). "Origins of agriculture at Kuk Swamp in the highlands of New Guinea" . Science . 301 (5630): 189–193. doi : 10.1126/science.1085255 . PMID 12817084 . S2CID 10644185 .
Scarcelli N, Cubry P, Akakpo R, Thuillet AC, Obidiegwu J, Baco MN, et al. (May 2019). "Yam genomics supports West Africa as a major cradle of crop domestication" . Science Advances . 5 (5): eaaw1947. Bibcode : 2019SciA....5.1947S . doi : 10.1126/sciadv.aaw1947 . PMC 6527260 . PMID 31114806 .
Winchell F (October 2017). "Evidence for Sorghum Domestication in Fourth Millennium BC Eastern Sudan: Spikelet Morphology from Ceramic Impressions of the Butana Group" (PDF) . Current Anthropology . 58 (5): 673–683. doi : 10.1086/693898 . S2CID 149402650 . Archived (PDF) from the original on 23 June 2021 . Retrieved 30 July 2022 .
Manning K (February 2011). "4500-Year old domesticated pearl millet (Pennisetum glaucum) from the Tilemsi Valley, Mali: new insights into an alternative cereal domestication pathway". Journal of Archaeological Science . 38 (2): 312–322. Bibcode : 2011JArSc..38..312M . doi : 10.1016/j.jas.2010.09.007 .
Noble TF, Strauss B, Osheim D, Neuschel K, Accamp E (2013). Cengage Advantage Books: Western Civilization: Beyond Boundaries . Cengage Learning. ISBN 978-1-285-66153-7 . Archived from the original on 27 February 2021 . Retrieved 11 July 2015 .
Spielvogel J (1 January 2014). Western Civilization: Volume A: To 1500 . Cenpage Learning. ISBN 978-1-285-98299-1 . Archived from the original on 10 August 2023 . Retrieved 11 July 2015 .
Thornton B (2002). Greek Ways: How the Greeks Created Western Civilization . San Francisco: Encounter Books. pp. 1–14. ISBN 978-1-893554-57-3 . Archived from the original on 10 August 2023 . Retrieved 30 July 2022 .
Garfinkle, Steven J. (2013). "Ancient Near Eastern City-States". In Peter Fibiger Bang ; Walter Scheidel (eds.). The Oxford Handbook of the State in the Ancient Near East and Mediterranean . Oxford Academic. pp. 94–119. doi : 10.1093/oxfordhb/9780195188318.013.0004 . ISBN 978-0-19-518831-8 .
Woods C (28 February 2020). "The Emergence of Cuneiform Writing". In Hasselbach-Andee R (ed.). A Companion to Ancient Near Eastern Languages (1st ed.). Wiley. pp. 27–46. doi : 10.1002/9781119193814.ch2 . ISBN 978-1-119-19329-6 . S2CID 216180781 .
Robinson A (October 2015). "Ancient civilization: Cracking the Indus script" . Nature . 526 (7574): 499–501. Bibcode : 2015Natur.526..499R . doi : 10.1038/526499a . PMID 26490603 . S2CID 4458743 .
Crawford H (2013). "Trade in the Sumerian world". The Sumerian World . Routledge. pp. 447–461. ISBN 978-1-136-21911-5 .
Bodnár M (2018). "Prehistoric innovations: Wheels and wheeled vehicles" . Acta Archaeologica Academiae Scientiarum Hungaricae . 69 (2): 271–298. doi : 10.1556/072.2018.69.2.3 . ISSN 0001-5210 . S2CID 115685157 . Archived from the original on 23 June 2021 . Retrieved 30 July 2022 .
Pryor FL (1985). "The Invention of the Plow" . Comparative Studies in Society and History . 27 (4): 727–743. doi : 10.1017/S0010417500011749 . ISSN 0010-4175 . JSTOR 178600 . S2CID 144840498 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 .
Carter R (2012). "19. Watercraft ". In Potts DT (ed.). A companion to the archaeology of the ancient Near East . Chichester, West Sussex: Wiley-Blackwell. pp. 347–354. ISBN 978-1-4051-8988-0 . Archived from the original on 28 April 2015 . Retrieved 8 February 2014 .
Pedersen O (1993). "Science Before the Greeks". Early physics and astronomy: A historical introduction . CUP Archive. p. 1. ISBN 978-0-521-40340-5 .
Edwards JF (2003). "Building the Great Pyramid: Probable Construction Methods Employed at Giza" . Technology and Culture . 44 (2): 340–354. doi : 10.1353/tech.2003.0063 . ISSN 0040-165X . JSTOR 25148110 . S2CID 109998651 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 .
Voosen P (August 2018). "New geological age comes under fire". Science . 361 (6402): 537–538. Bibcode : 2018Sci...361..537V . doi : 10.1126/science.361.6402.537 . PMID 30093579 . S2CID 51954326 .
Sassaman KE (1 December 2005). "Poverty Point as Structure, Event, Process". Journal of Archaeological Method and Theory . 12 (4): 335–364. doi : 10.1007/s10816-005-8460-4 . ISSN 1573-7764 . S2CID 53393440 .
Lazaridis I, Mittnik A, Patterson N, Mallick S, Rohland N, Pfrengle S, et al. (August 2017). "Genetic origins of the Minoans and Mycenaeans" . Nature . 548 (7666): 214–218. Bibcode : 2017Natur.548..214L . doi : 10.1038/nature23310 . PMC 5565772 . PMID 28783727 .
Keightley DN (1999). "The Shang: China's first historical dynasty". In Loewe M, Shaughnessy EL (eds.). The Cambridge History of Ancient China: From the Origins of Civilization to 221 BC . Cambridge University Press. pp. 232–291. ISBN 978-0-521-47030-8 .
Kaniewski D, Guiot J, van Campo E (2015). "Drought and societal collapse 3200 years ago in the Eastern Mediterranean: a review". WIREs Climate Change . 6 (4): 369–382. Bibcode : 2015WIRCC...6..369K . doi : 10.1002/wcc.345 . S2CID 128460316 .
Drake BL (1 June 2012). "The influence of climatic change on the Late Bronze Age Collapse and the Greek Dark Ages". Journal of Archaeological Science . 39 (6): 1862–1870. Bibcode : 2012JArSc..39.1862D . doi : 10.1016/j.jas.2012.01.029 .
Wells PS (2011). "The Iron Age". In Milisauskas S (ed.). European Prehistory . Interdisciplinary Contributions to Archaeology. New York, NY: Springer. pp. 405–460. doi : 10.1007/978-1-4419-6633-9_11 . ISBN 978-1-4419-6633-9 .
Hughes-Warrington M (2018). "Sense and non-sense in Ancient Greek histories". History as Wonder: Beginning with Historiography . United Kingdom: Taylor & Francis. ISBN 978-0-429-76315-1 .
Beard M (2 October 2015). "Why ancient Rome matters to the modern world" . The Guardian . Archived from the original on 14 April 2021 . Retrieved 17 April 2021 .
Vidergar AB (11 June 2015). "Stanford scholar debunks long-held beliefs about economic growth in ancient Greece" . Stanford University . Archived from the original on 18 April 2021 . Retrieved 17 April 2021 .
Inomata T, Triadan D, Vázquez López VA, Fernandez-Diaz JC, Omori T, Méndez Bauer MB, et al. (June 2020). "Monumental architecture at Aguada Fénix and the rise of Maya civilization". Nature . 582 (7813): 530–533. Bibcode : 2020Natur.582..530I . doi : 10.1038/s41586-020-2343-4 . PMID 32494009 . S2CID 219281856 .
Milbrath S (March 2017). "The Role of Solar Observations in Developing the Preclassic Maya Calendar" . Latin American Antiquity . 28 (1): 88–104. doi : 10.1017/laq.2016.4 . ISSN 1045-6635 . S2CID 164417025 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Benoist A, Charbonnier J, Gajda I (2016). "Investigating the eastern edge of the kingdom of Aksum: architecture and pottery from Wakarida" . Proceedings of the Seminar for Arabian Studies . 46 : 25–40. ISSN 0308-8421 . JSTOR 45163415 . Archived from the original on 28 April 2022 . Retrieved 30 July 2022 .
Farazmand A (1 January 1998). "Administration of the Persian achaemenid world-state empire: implications for modern public administration". International Journal of Public Administration . 21 (1): 25–86. doi : 10.1080/01900699808525297 . ISSN 0190-0692 .
Ingalls DH (1976). "Kālidāsa and the Attitudes of the Golden Age" . Journal of the American Oriental Society . 96 (1): 15–26. doi : 10.2307/599886 . ISSN 0003-0279 . JSTOR 599886 . Archived from the original on 9 April 2022 . Retrieved 30 July 2022 .
Xie J (2020). "Pillars of Heaven: The Symbolic Function of Column and Bracket Sets in the Han Dynasty" . Architectural History . 63 : 1–36. doi : 10.1017/arh.2020.1 . ISSN 0066-622X . S2CID 229716130 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Marx W, Haunschild R, Bornmann L (2018). "Climate and the Decline and Fall of the Western Roman Empire: A Bibliometric View on an Interdisciplinary Approach to Answer a Most Classic Historical Question" . Climate . 6 (4): 90. Bibcode : 2018Clim....6...90M . doi : 10.3390/cli6040090 .
Brooke JH, Numbers RL, eds. (2011). Science and Religion Around the World . New York: Oxford University Press. p. 72. ISBN 978-0-19-532819-6 . Retrieved 30 July 2022 .
Renima A, Tiliouine H, Estes RJ (2016). "The Islamic Golden Age: A Story of the Triumph of the Islamic Civilization". In Tiliouine H, Estes RJ (eds.). The State of Social Progress of Islamic Societies . International Handbooks of Quality-of-Life. Cham: Springer International Publishing. pp. 25–52. doi : 10.1007/978-3-319-24774-8_2 . ISBN 978-3-319-24774-8 .
Asbridge T (2012). "Introduction: The world of the crusades". The Crusades: The War for the Holy Land . Simon and Schuster. ISBN 978-1-84983-770-5 .
Adam King (2002). "Mississippian Period: Overview" . New Georgia Encyclopedia . Archived from the original on 19 August 2009 . Retrieved 15 November 2009 .
Conrad G, Demarest AA (1984). Religion and Empire: The Dynamics of Aztec and Inca Expansionism . Cambridge University Press. p. 2. ISBN 0-521-31896-3 .
Canós-Donnay S (25 February 2019). "The Empire of Mali" . Oxford Research Encyclopedia of African History . Oxford University Press. doi : 10.1093/acrefore/9780190277734.013.266 . ISBN 978-0-19-027773-4 . Archived from the original on 20 October 2021 . Retrieved 7 May 2021 .
Canela SA, Graves MW. "The Tongan Maritime Expansion: A Case in the Evolutionary Ecology of Social Complexity" . Asian Perspectives . 37 (2): 135–164.
Kafadar C (1 January 1994). "Ottomans and Europe" . In Brady T, Oberman T, Tracy JD (eds.). Handbook of European History 1400–1600: Late Middle Ages, Renaissance and Reformation . Brill. pp. 589–635. doi : 10.1163/9789004391659_019 . ISBN 978-90-04-39165-9 . Archived from the original on 2 May 2022 . Retrieved 17 April 2021 .
Goree R (19 November 2020). "The Culture of Travel in Edo-Period Japan" . Oxford Research Encyclopedia of Asian History . Oxford University Press. doi : 10.1093/acrefore/9780190277727.013.72 . ISBN 978-0-19-027772-7 . Archived from the original on 12 August 2021 . Retrieved 7 May 2021 .
Mosca MW (2010). "CHINA'S LAST EMPIRE: The Great Qing" . Pacific Affairs . 83 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 .
Suyanta S, Ikhlas S (19 July 2016). "Islamic Education at Mughal Kingdom in India (1526–1857)" . Al-Ta Lim Journal . 23 (2): 128–138. doi : 10.15548/jt.v23i2.228 . ISSN 2355-7893 . Archived from the original on 7 April 2022 . Retrieved 30 July 2022 .
Kirkpatrick R (2002). The European Renaissance, 1400–1600 . Routledge. p. 1. ISBN 978-1-317-88646-4 . OCLC 893909816 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Arnold D (2002). The Age of Discovery, 1400–1600 (Second ed.). Routledge. pp. xi. ISBN 978-1-136-47968-7 . OCLC 859536800 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Palan R (14 January 2010). "International Financial Centers: The British-Empire, City-States and Commercially Oriented Politics" . Theoretical Inquiries in Law . 11 (1). doi : 10.2202/1565-3404.1239 . ISSN 1565-3404 . S2CID 56216309 . Archived from the original on 26 August 2021 . Retrieved 30 July 2022 .
Dixon EJ (January 2001). "Human colonization of the Americas: timing, technology and process". Quaternary Science Reviews . 20 (1–3): 277–299. Bibcode : 2001QSRv...20..277J . doi : 10.1016/S0277-3791(00)00116-5 .
Lovejoy PE (1989). "The Impact of the Atlantic Slave Trade on Africa: A Review of the Literature" . The Journal of African History . 30 (3): 365–394. doi : 10.1017/S0021853700024439 . ISSN 0021-8537 . JSTOR 182914 . S2CID 161321949 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 .
Cave AA (2008). "Genocide in the Americas". In Stone D (ed.). The Historiography of Genocide . London: Palgrave Macmillan UK. pp. 273–295. doi : 10.1057/9780230297784_11 . ISBN 978-0-230-29778-4 .
Delisle RG (September 2014). "Can a revolution hide another one? Charles Darwin and the Scientific Revolution". Endeavour . 38 (3–4): 157–158. doi : 10.1016/j.endeavour.2014.10.001 . PMID 25457642 .
"Greatest Engineering Achievements of the 20th Century" . National Academy of Engineering . Archived from the original on 6 April 2015 . Retrieved 7 April 2015 .
Herring GC (2008). From colony to superpower : U.S. foreign relations since 1776 . New York: Oxford University Press. p. 1. ISBN 978-0-19-972343-0 . OCLC 299054528 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
O'Rourke KH (March 2006). "The worldwide economic impact of the French Revolutionary and Napoleonic Wars, 1793–1815" . Journal of Global History . 1 (1): 123–149. doi : 10.1017/S1740022806000076 . ISSN 1740-0228 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Zimmerman AF (November 1931). "Spain and Its Colonies, 1808–1820" . The Hispanic American Historical Review . 11 (4): 439–463. doi : 10.2307/2506251 . JSTOR 2506251 . Archived from the original on 6 March 2022 . Retrieved 30 July 2022 .
David S (2011). "British History in depth: Slavery and the 'Scramble for Africa' " . BBC . Archived from the original on 24 March 2022 . Retrieved 5 May 2021 .
Raudzens G (2004). "The Australian Frontier Wars, 1788–1838 (review)" . The Journal of Military History . 68 (3): 957–959. doi : 10.1353/jmh.2004.0138 . ISSN 1543-7795 . S2CID 162259092 .
Clark CM (2012). "Polarization of Europe, 1887–1907". The sleepwalkers : how Europe went to war in 1914 . London: Allen Lane. ISBN 978-0-7139-9942-6 . OCLC 794136314 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
McDougall WA (May 1985). "Sputnik, the space race, and the Cold War" . Bulletin of the Atomic Scientists . 41 (5): 20–25. Bibcode : 1985BuAtS..41e..20M . doi : 10.1080/00963402.1985.11455962 . ISSN 0096-3402 .
Plous S (May 1993). "The Nuclear Arms Race: Prisoner's Dilemma or Perceptual Dilemma?" . Journal of Peace Research . 30 (2): 163–179. doi : 10.1177/0022343393030002004 . ISSN 0022-3433 . S2CID 5482851 . Archived from the original on 21 February 2022 . Retrieved 30 July 2022 .
Sachs JD (April 2017). "Globalization – In the Name of Which Freedom?" . Humanistic Management Journal . 1 (2): 237–252. doi : 10.1007/s41463-017-0019-5 . ISSN 2366-603X . S2CID 133030709 .
"World" . The World Factbook . CIA . 17 May 2016. Archived from the original on 26 January 2021 . Retrieved 2 October 2016 .
"World Population Prospects: The 2017 Revision" (PDF) . United Nations, Department of Economic and Social Affairs, Population Division. 2017. p. 2&17. Archived (PDF) from the original on 26 June 2019 . Retrieved 30 July 2022 .
Rector RK (2016). The Early River Valley Civilizations (First ed.). New York: Rosen Publishing. p. 10. ISBN 978-1-4994-6329-3 . OCLC 953735302 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
"How People Modify the Environment" (PDF) . Westerville City School District . Archived (PDF) from the original on 25 February 2021 . Retrieved 13 March 2019 .
"Natural disasters and the urban poor" (PDF) . World Bank . October 2003. Archived (PDF) from the original on 9 August 2017.
Habitat UN (2013). The state of the world's cities 2012 / prosperity of cities . [London]: Routledge. pp. x. ISBN 978-1-135-01559-6 . OCLC 889953315 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Piantadosi CA (2003). The biology of human survival : life and death in extreme environments . Oxford: Oxford University Press. pp. 2–3. ISBN 978-0-19-974807-5 . OCLC 70215878 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Toups, M.A.; Kitchen, A.; Light, J.E.; Reed, D.L. (2011). "Origin of clothing lice indicates early clothing use by anatomically modern humans in Africa" . Molecular Biology and Evolution . 28 (1): 29–32. doi : 10.1093/molbev/msq234 . PMC 3002236 . PMID 20823373 .
O'Neil D. "Human Biological Adaptability; Overview" . Palomar College. Archived from the original on 6 March 2013 . Retrieved 6 January 2013 .
"Population distribution and density" . BBC. Archived from the original on 23 June 2017 . Retrieved 26 June 2017 .
Bunn SE, Arthington AH (October 2002). "Basic principles and ecological consequences of altered flow regimes for aquatic biodiversity". Environmental Management . 30 (4): 492–507. doi : 10.1007/s00267-002-2737-0 . hdl : 10072/6758 . PMID 12481916 . S2CID 25834286 .
Heim BE (1990–1991). "Exploring the Last Frontiers for Mineral Resources: A Comparison of International Law Regarding the Deep Seabed, Outer Space, and Antarctica" . Vanderbilt Journal of Transnational Law . 23 : 819. Archived from the original on 23 June 2021 . Retrieved 30 July 2022 .
"Mission to Mars: Mars Science Laboratory Curiosity Rover" . Jet Propulsion Laboratory. Archived from the original on 18 August 2015 . Retrieved 26 August 2015 .
"Touchdown! Rosetta's Philae probe lands on comet" . European Space Agency. 12 November 2014. Archived from the original on 22 August 2015 . Retrieved 26 August 2015 .
Kraft R (11 December 2010). "JSC celebrates ten years of continuous human presence aboard the International Space Station" . JSC Features . Johnson Space Center . Archived from the original on 16 February 2012 . Retrieved 13 February 2012 .
Bar-On YM, Phillips R, Milo R (June 2018). "The biomass distribution on Earth" . Proceedings of the National Academy of Sciences of the United States of America . 115 (25): 6506–6511. Bibcode : 2018PNAS..115.6506B . doi : 10.1073/pnas.1711842115 . PMC 6016768 . PMID 29784790 .
Tellier LN (2009). Urban world history: an economic and geographical perspective . Presses de l'Université du Québec. p. 26. ISBN 978-2-7605-1588-8 . Retrieved 30 July 2022 .
Thomlinson R (1975). Demographic problems; controversy over population control (2nd ed.). Ecino, CA: Dickenson Pub. Co. ISBN 978-0-8221-0166-6 .
Harl KW (1998). "Population estimates of the Roman Empire" . Tulane.edu. Archived from the original on 7 May 2016 . Retrieved 8 December 2012 .
Zietz BP, Dunkelberg H (February 2004). "The history of the plague and the research on the causative agent Yersinia pestis" . International Journal of Hygiene and Environmental Health . 207 (2): 165–178. doi : 10.1078/1438-4639-00259 . PMC 7128933 . PMID 15031959 .
"World's population reaches six billion" . BBC News . 5 August 1999. Archived from the original on 15 April 2008 . Retrieved 5 February 2008 .
United Nations. "World population to reach 8 billion on 15 November 2022" . United Nations . Archived from the original on 20 January 2023 . Retrieved 27 October 2022 .
"Eight billion people, SARS-CoV-2 ancestor and illegal fishing" . Nature . 611 (641): 641. 23 November 2022. Bibcode : 2022Natur.611..641. . doi : 10.1038/d41586-022-03792-4 . S2CID 253764233 . Archived from the original on 26 January 2023 . Retrieved 26 January 2023 .
"World Population to Hit Milestone With Birth of 7 Billionth Person" . PBS NewsHour . 27 October 2011. Archived from the original on 24 September 2017 . Retrieved 11 February 2018 .
"68% of the world population projected to live in urban areas by 2050, says UN" . United Nations Department of Economic and Social Affairs (DESA) . 16 May 2018. Archived from the original on 10 March 2021 . Retrieved 18 April 2021 .
Duhart DT (October 2000). Urban, Suburban, and Rural Victimization, 1993–98 (PDF) . U.S. Department of Justice , Bureau of Justice Statistics. Archived (PDF) from the original on 24 February 2013 . Retrieved 1 October 2006 .
Roopnarine PD (March 2014). "Humans are apex predators" . Proceedings of the National Academy of Sciences of the United States of America . 111 (9): E796. Bibcode : 2014PNAS..111E.796R . doi : 10.1073/pnas.1323645111 . PMC 3948303 . PMID 24497513 .
Stokstad E (5 May 2019). "Landmark analysis documents the alarming global decline of nature" . Science . AAAS . Archived from the original on 26 October 2021 . Retrieved 9 May 2021 . For the first time at a global scale, the report has ranked the causes of damage. Topping the list, changes in land use – principally agriculture – that have destroyed habitat. Second, hunting and other kinds of exploitation. These are followed by climate change, pollution, and invasive species, which are being spread by trade and other activities. Climate change will likely overtake the other threats in the next decades, the authors note. Driving these threats are the growing human population, which has doubled since 1970 to 7.6 billion, and consumption. (Per capita of use of materials is up 15% over the past 5 decades.)
Pimm S, Raven P, Peterson A, Sekercioglu CH, Ehrlich PR (July 2006). "Human impacts on the rates of recent, present, and future bird extinctions" . Proceedings of the National Academy of Sciences of the United States of America . 103 (29): 10941–10946. Bibcode : 2006PNAS..10310941P . doi : 10.1073/pnas.0604181103 . PMC 1544153 . PMID 16829570 .
Weisberger, Mindy (March 23, 2024). "Why don't humans have tails? Scientists find answers in an unlikely place" . CNN . Archived from the original on March 24, 2024 . Retrieved March 24, 2024 .
Marks JM (2001). Human Biodiversity: Genes, Race, and History . Transaction Publishers. p. 16. ISBN 978-0-202-36656-2 .
Gea, J (2008). "The Evolution of the Human Species: A Long Journey for the Respiratory System". Archivos de Bronconeumología ((English Edition)) . 44 (5): 263–270. doi : 10.1016/S1579-2129(08)60042-7 .
O'Neil D. "Humans" . Primates . Palomar College. Archived from the original on 11 January 2013 . Retrieved 6 January 2013 .
"How to be Human: The reason we are so scarily hairy" . New Scientist . 2017. Archived from the original on 25 February 2021 . Retrieved 29 April 2020 .
Sandel AA (September 2013). "Brief communication: Hair density and body mass in mammals and the evolution of human hairlessness". American Journal of Physical Anthropology . 152 (1): 145–150. doi : 10.1002/ajpa.22333 . hdl : 2027.42/99654 . PMID 23900811 .
Kirchweger G (2 February 2001). "The Biology of Skin Color: Black and White" . Evolution: Library . PBS. Archived from the original on 16 February 2013 . Retrieved 6 January 2013 .
Roser M, Appel C, Ritchie H (8 October 2013). "Human Height" . Our World in Data . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 .
"Senior Citizens Do Shrink – Just One of the Body Changes of Aging" . News . Senior Journal. Archived from the original on 19 February 2013 . Retrieved 6 January 2013 .
Bogin B, Rios L (September 2003). "Rapid morphological change in living humans: implications for modern human origins". Comparative Biochemistry and Physiology. Part A, Molecular & Integrative Physiology . 136 (1): 71–84. doi : 10.1016/S1095-6433(02)00294-5 . PMID 14527631 .
"Human weight" . Articleworld.org. Archived from the original on 8 December 2011 . Retrieved 10 December 2011 .
Schlessingerman A (2003). "Mass Of An Adult" . The Physics Factbook: An Encyclopedia of Scientific Essays. Archived from the original on 1 January 2018 . Retrieved 31 December 2017 .
Kushner R (2007). Treatment of the Obese Patient (Contemporary Endocrinology) . Totowa, NJ: Humana Press. p. 158. ISBN 978-1-59745-400-1 . Retrieved 5 April 2009 .
Adams JP, Murphy PG (July 2000). "Obesity in anaesthesia and intensive care" . British Journal of Anaesthesia . 85 (1): 91–108. doi : 10.1093/bja/85.1.91 . PMID 10927998 .
Lombardo MP, Deaner RO (March 2018). "Born to Throw: The Ecological Causes that Shaped the Evolution of Throwing In Humans". The Quarterly Review of Biology . 93 (1): 1–16. doi : 10.1086/696721 . ISSN 0033-5770 . S2CID 90757192 .
Parker-Pope T (27 October 2009). "The Human Body Is Built for Distance" . The New York Times . Archived from the original on 5 November 2015.
John B. "What is the role of sweating glands in balancing body temperature when running a marathon?" . Livestrong.com. Archived from the original on 31 January 2013 . Retrieved 6 January 2013 .
Shave, R. E.; Lieberman, D. E.; Drane, A. L.; et al. (2019). "Selection of endurance capabilities and the trade-off between pressure and volume in the evolution of the human heart" . PNAS . 116 (40): 19905–19910. Bibcode : 2019PNAS..11619905S . doi : 10.1073/pnas.1906902116 . PMC 6778238 . PMID 31527253 .
Ríos, L; Sleeper, M. M.; Danforth, M. D.; et al. (2023). "The aorta in humans and African great apes, and cardiac output and metabolic levels in human evolution" . Scientific Reports . 13 (6841): 6841. Bibcode : 2023NatSR..13.6841R . doi : 10.1038/s41598-023-33675-1 . hdl : 10261/309357 . PMC 10133235 . PMID 37100851 .
Therman E (1980). Human Chromosomes: Structure, Behavior, Effects . Springer US . pp. 112–124. doi : 10.1007/978-1-4684-0107-3 . ISBN 978-1-4684-0109-7 . S2CID 36686283 .
Edwards JH, Dent T, Kahn J (June 1966). "Monozygotic twins of different sex" . Journal of Medical Genetics . 3 (2): 117–123. doi : 10.1136/jmg.3.2.117 . PMC 1012913 . PMID 6007033 .
Machin GA (January 1996). "Some causes of genotypic and phenotypic discordance in monozygotic twin pairs". American Journal of Medical Genetics . 61 (3): 216–228. doi : 10.1002/(SICI)1096-8628(19960122)61:3<216::AID-AJMG5>3.0.CO;2-S . PMID 8741866 .
Jonsson H, Magnusdottir E, Eggertsson HP, Stefansson OA, Arnadottir GA, Eiriksson O, et al. (January 2021). "Differences between germline genomes of monozygotic twins". Nature Genetics . 53 (1): 27–34. doi : 10.1038/s41588-020-00755-1 . PMID 33414551 . S2CID 230986741 .
"Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . Between any two humans, the amount of genetic variation – biochemical individuality – is about 0.1%.
Levy S, Sutton G, Ng PC, Feuk L, Halpern AL, Walenz BP, et al. (September 2007). "The diploid genome sequence of an individual human" . PLOS Biology . 5 (10): e254. doi : 10.1371/journal.pbio.0050254 . PMC 1964779 . PMID 17803354 .
Race, Ethnicity, and Genetics Working Group (October 2005). "The use of racial, ethnic, and ancestral categories in human genetics research" . American Journal of Human Genetics . 77 (4): 519–532. doi : 10.1086/491747 . PMC 1275602 . PMID 16175499 .
"Chimps show much greater genetic diversity than humans" . Media . University of Oxford. Archived from the original on 18 December 2013 . Retrieved 13 December 2013 .
Harpending HC, Batzer MA, Gurven M, Jorde LB, Rogers AR, Sherry ST (February 1998). "Genetic traces of ancient demography" . Proceedings of the National Academy of Sciences of the United States of America . 95 (4): 1961–1967. Bibcode : 1998PNAS...95.1961H . doi : 10.1073/pnas.95.4.1961 . PMC 19224 . PMID 9465125 .
Jorde LB, Rogers AR, Bamshad M, Watkins WS, Krakowiak P, Sung S, et al. (April 1997). "Microsatellite diversity and the demographic history of modern humans" . Proceedings of the National Academy of Sciences of the United States of America . 94 (7): 3100–3103. Bibcode : 1997PNAS...94.3100J . doi : 10.1073/pnas.94.7.3100 . PMC 20328 . PMID 9096352 .
Wade N (7 March 2007). "Still Evolving, Human Genes Tell New Story" . The New York Times . Archived from the original on 14 January 2012 . Retrieved 13 February 2012 .
Pennisi E (February 2001). "The human genome". Science . 291 (5507): 1177–1180. doi : 10.1126/science.291.5507.1177 . PMID 11233420 . S2CID 38355565 .
Rotimi CN, Adeyemo AA (February 2021). "From one human genome to a complex tapestry of ancestry". Nature . 590 (7845): 220–221. Bibcode : 2021Natur.590..220R . doi : 10.1038/d41586-021-00237-2 . PMID 33568827 . S2CID 231882262 .
Altshuler DM, Gibbs RA, Peltonen L, Altshuler DM, Gibbs RA, Peltonen L, et al. (September 2010). "Integrating common and rare genetic variation in diverse human populations" . Nature . 467 (7311): 52–58. Bibcode : 2010Natur.467...52T . doi : 10.1038/nature09298 . PMC 3173859 . PMID 20811451 .
Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . Populations in central and southern Africa, the Americas, and Oceania each harbor tens to hundreds of thousands of private , common genetic variants. Most of these variants arose as new mutations rather than through archaic introgression, except in Oceanian populations, where many private variants derive from Denisovan admixture.
Pertea M, Salzberg SL (2010). "Between a chicken and a grape: estimating the number of human genes" . Genome Biology . 11 (5): 206. doi : 10.1186/gb-2010-11-5-206 . PMC 2898077 . PMID 20441615 .
Cann RL, Stoneking M, Wilson AC (1987). "Mitochondrial DNA and human evolution". Nature . 325 (6099): 31–36. Bibcode : 1987Natur.325...31C . doi : 10.1038/325031a0 . PMID 3025745 . S2CID 4285418 .
Soares P, Ermini L, Thomson N, Mormina M, Rito T, Röhl A, et al. (June 2009). "Correcting for purifying selection: an improved human mitochondrial molecular clock" . American Journal of Human Genetics . 84 (6): 740–759. doi : 10.1016/j.ajhg.2009.05.001 . PMC 2694979 . PMID 19500773 .
"University of Leeds | News > Technology > New 'molecular clock' aids dating of human migration history" . 20 August 2017. Archived from the original on 20 August 2017.
Poznik GD, Henn BM, Yee MC, Sliwerska E, Euskirchen GM, Lin AA, et al. (August 2013). "Sequencing Y chromosomes resolves discrepancy in time to common ancestor of males versus females" . Science . 341 (6145): 562–565. Bibcode : 2013Sci...341..562P . doi : 10.1126/science.1237619 . PMC 4032117 . PMID 23908239 .
Shehan CL (2016). The Wiley Blackwell Encyclopedia of Family Studies, 4 Volume Set . John Wiley & Sons. p. 406. ISBN 978-0-470-65845-1 .
Jukic AM, Baird DD, Weinberg CR , McConnaughey DR, Wilcox AJ (October 2013). "Length of human pregnancy and contributors to its natural variation" . Human Reproduction . 28 (10): 2848–2855. doi : 10.1093/humrep/det297 . PMC 3777570 . PMID 23922246 .
Klossner NJ (2005). Introductory Maternity Nursing . Lippincott Williams & Wilkins. p. 103. ISBN 978-0-7817-6237-3 . Archived from the original on 8 April 2022 . Retrieved 30 July 2022 . The fetal stage is from the beginning of the 9th week after fertilization and continues until birth
World Health Organization (November 2014). "Preterm birth Fact sheet N°363" . who.int . Archived from the original on 7 March 2015 . Retrieved 6 March 2015 .
Kiserud T, Benachi A, Hecher K, Perez RG, Carvalho J, Piaggio G, Platt LD (February 2018). "The World Health Organization fetal growth charts: concept, findings, interpretation, and application" . American Journal of Obstetrics and Gynecology . 218 (2S): S619–S629. doi : 10.1016/j.ajog.2017.12.010 . PMID 29422204 . S2CID 46810955 .
"What is the average baby length? Growth chart by month" . www.medicalnewstoday.com . 18 March 2019. Archived from the original on 27 January 2021 . Retrieved 18 April 2021 .
Khor GL (December 2003). "Update on the prevalence of malnutrition among children in Asia". Nepal Medical College Journal . 5 (2): 113–122. PMID 15024783 .
Rosenberg KR (1992). "The evolution of modern human childbirth". American Journal of Physical Anthropology . 35 (S15): 89–124. doi : 10.1002/ajpa.1330350605 . ISSN 1096-8644 .
Pavličev M, Romero R, Mitteroecker P (January 2020). "Evolution of the human pelvis and obstructed labor: new explanations of an old obstetrical dilemma" . American Journal of Obstetrics and Gynecology . 222 (1): 3–16. doi : 10.1016/j.ajog.2019.06.043 . PMC 9069416 . PMID 31251927 . S2CID 195761874 .
Kantrowitz B (2 July 2007). "What Kills One Woman Every Minute of Every Day?" . Newsweek . Archived from the original on 28 June 2007. A woman dies in childbirth every minute, most often due to uncontrolled bleeding and infection, with the world's poorest women most vulnerable. The lifetime risk is 1 in 16 in sub-Saharan Africa , compared to 1 in 2,800 in developed countries .
Rush D (July 2000). "Nutrition and maternal mortality in the developing world" . The American Journal of Clinical Nutrition . 72 (1 Suppl): 212S–240S. doi : 10.1093/ajcn/72.1.212S . PMID 10871588 .
Laland KN, Brown G (2011). Sense and Nonsense: Evolutionary Perspectives on Human Behaviour . Oxford University Press. p. 7. ISBN 978-0-19-958696-7 . Retrieved 30 July 2022 .
Kail RV, Cavanaugh JC (2010). Human Development: A Lifespan View (5th ed.). Cengage Learning . p. 296. ISBN 978-0-495-60037-4 . Archived from the original on 3 October 2023 . Retrieved 30 July 2022 .
Schuiling KD, Likis FE (2016). Women's Gynecologic Health . Jones & Bartlett Learning . p. 22. ISBN 978-1-284-12501-6 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . The changes that occur during puberty usually happen in an ordered sequence, beginning with thelarche (breast development) at around age 10 or 11, followed by adrenarche (growth of pubic hair due to androgen stimulation), peak height velocity, and finally menarche (the onset of menses), which usually occurs around age 12 or 13.
Phillips DC (2014). Encyclopedia of Educational Theory and Philosophy . SAGE Publications . pp. 18–19. ISBN 978-1-4833-6475-9 . Archived from the original on 10 January 2023 . Retrieved 30 July 2022 . On average, the onset of puberty is about 18 months earlier for girls (usually starting around the age of 10 or 11 and lasting until they are 15 to 17) than for boys (who usually begin puberty at about the age of 11 to 12 and complete it by the age of 16 to 17, on average).
Soliman A, De Sanctis V, Elalaily R, Bedair S (November 2014). "Advances in pubertal growth and factors influencing it: Can we increase pubertal growth?" . Indian Journal of Endocrinology and Metabolism . 18 (Suppl 1): S53-62. doi : 10.4103/2230-8210.145075 . PMC 4266869 . PMID 25538878 .
Walker ML, Herndon JG (September 2008). "Menopause in nonhuman primates?" . Biology of Reproduction . 79 (3): 398–406. doi : 10.1095/biolreprod.108.068536 . PMC 2553520 . PMID 18495681 .
Diamond J (1997). Why is Sex Fun? The Evolution of Human Sexuality . New York: Basic Books. pp. 167–170. ISBN 978-0-465-03127-6 .
Peccei JS (2001). "Menopause: Adaptation or epiphenomenon?". Evolutionary Anthropology . 10 (2): 43–57. doi : 10.1002/evan.1013 . S2CID 1665503 .
Marziali C (7 December 2010). "Reaching Toward the Fountain of Youth" . USC Trojan Family Magazine . Archived from the original on 13 December 2010 . Retrieved 7 December 2010 .
Kalben BB (2002). "Why Men Die Younger: Causes of Mortality Differences by Sex" . Society of Actuaries. Archived from the original on 1 July 2013.
"Life expectancy at birth, female (years)" . World Bank . 2018. Archived from the original on 24 January 2021 . Retrieved 13 October 2020 .
"Life expectancy at birth, male (years)" . World Bank . 2018. Archived from the original on 24 February 2021 . Retrieved 13 October 2020 .
Conceição P, et al. (2019). Human Development Report (PDF) . United Nations Development Programme. ISBN 978-92-1-126439-5 . Archived (PDF) from the original on 20 March 2021 . Retrieved 30 July 2022 .
"Human Development Report 2019" (PDF) . United Nations Development Programme . Archived from the original (PDF) on 22 April 2022 . Retrieved 30 July 2022 .
"The World Factbook" . U.S. Central Intelligence Agency. Archived from the original on 12 September 2009 . Retrieved 2 April 2005 .
"Chapter 1: Setting the Scene" (PDF) . UNFPA. 2012. Archived from the original (PDF) on 12 June 2013 . Retrieved 11 January 2013 .
Cordain L (2007). "Implications of Plio-pleistocene diets for modern humans". In Ungar PS (ed.). Evolution of the human diet: the known, the unknown and the unknowable . pp. 264–265. Since the evolutionary split between hominins and pongids approximately 7 million years ago, the available evidence shows that all species of hominins ate an omnivorous diet composed of minimally processed, wild-plant, and animal foods.
American Dietetic Association (June 2003). "Position of the American Dietetic Association and Dietitians of Canada: Vegetarian diets". Journal of the American Dietetic Association . 103 (6): 748–765. doi : 10.1053/jada.2003.50142 . PMID 12778049 .
Crittenden AN, Schnorr SL (2017). "Current views on hunter-gatherer nutrition and the evolution of the human diet" . American Journal of Physical Anthropology . 162 (S63): 84–109. doi : 10.1002/ajpa.23148 . PMID 28105723 .
Cordain L, Eaton SB, Sebastian A, Mann N, Lindeberg S, Watkins BA, et al. (February 2005). "Origins and evolution of the Western diet: health implications for the 21st century" . The American Journal of Clinical Nutrition . 81 (2): 341–354. doi : 10.1093/ajcn.81.2.341 . PMID 15699220 .
Ulijaszek SJ (November 2002). "Human eating behaviour in an evolutionary ecological context" . The Proceedings of the Nutrition Society . 61 (4): 517–526. doi : 10.1079/PNS2002180 . PMID 12691181 .
John Carey (2023). "Unearthing the origins of agriculture" . Proceedings of the National Academy of Sciences . 120 (15): e2304407120. Bibcode : 2023PNAS..12004407C . doi : 10.1073/pnas.2304407120 . PMC 10104519 . PMID 37018195 .
Ayelet Shavit; Gonen Sharon (2023). "Can models of evolutionary transition clarify the debates over the Neolithic Revolution?" . Philosophical Transactions of the Royal Society B . 378 (1872). doi : 10.1098/rstb.2021.0413 . PMC 9869441 . PMID 36688395 . }
Krebs JR (September 2009). "The gourmet ape: evolution and human food preferences" . The American Journal of Clinical Nutrition . 90 (3): 707S–711S. doi : 10.3945/ajcn.2009.27462B . PMID 19656837 .
Holden C, Mace R (October 1997). "Phylogenetic analysis of the evolution of lactose digestion in adults". Human Biology . 69 (5): 605–628. PMID 9299882 .
Gibbons A. "The Evolution of Diet" . National Geographic . Archived from the original on 18 August 2014 . Retrieved 18 April 2021 .
Ritchie H, Roser M (20 August 2017). "Diet Compositions" . Our World in Data . Archived from the original on 25 August 2021 . Retrieved 30 July 2022 .
Lieberson AD (2004). "How Long Can a Person Survive without Food?" . Scientific American . Archived from the original on 14 February 2019 . Retrieved 18 April 2021 .
Spector D (9 March 2018). "Here's how many days a person can survive without water" . Business Insider Australia . Archived from the original on 26 June 2014 . Retrieved 18 April 2021 .
Holmes J. "Losing 25,000 to Hunger Every Day" . United Nations . Archived from the original on 27 May 2020 . Retrieved 18 April 2021 .
Mai HJ (2020). "U.N. Warns Number Of People Starving To Death Could Double Amid Pandemic" . NPR . Archived from the original on 28 June 2021 . Retrieved 18 April 2021 .
Murray CJ, Lopez AD (May 1997). "Global mortality, disability, and the contribution of risk factors: Global Burden of Disease Study". Lancet . 349 (9063): 1436–1442. doi : 10.1016/S0140-6736(96)07495-8 . PMID 9164317 . S2CID 2569153 .
Haslam DW, James WP (October 2005). "Obesity". Lancet . 366 (9492): 1197–1209. doi : 10.1016/S0140-6736(05)67483-1 . PMID 16198769 . S2CID 208791491 .
Catenacci VA, Hill JO, Wyatt HR (September 2009). "The obesity epidemic". Clinics in Chest Medicine . 30 (3): 415–444, vii. doi : 10.1016/j.ccm.2009.05.001 . PMID 19700042 .
de Beer H (March 2004). "Observations on the history of Dutch physical stature from the late-Middle Ages to the present". Economics and Human Biology . 2 (1): 45–55. doi : 10.1016/j.ehb.2003.11.001 . PMID 15463992 .
O'Neil D. "Adapting to Climate Extremes" . Human Biological Adaptability . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 .
Rask-Andersen M, Karlsson T, Ek WE, Johansson Å (September 2017). "Gene-environment interaction study for BMI reveals interactions between genetic factors and physical activity, alcohol consumption and socioeconomic status" . PLOS Genetics . 13 (9): e1006977. doi : 10.1371/journal.pgen.1006977 . PMC 5600404 . PMID 28873402 .
Beja-Pereira A, Luikart G, England PR, Bradley DG, Jann OC, Bertorelle G, et al. (December 2003). "Gene-culture coevolution between cattle milk protein genes and human lactase genes". Nature Genetics . 35 (4): 311–313. doi : 10.1038/ng1263 . PMID 14634648 . S2CID 20415396 .
Hedrick PW (October 2011). "Population genetics of malaria resistance in humans" . Heredity . 107 (4): 283–304. doi : 10.1038/hdy.2011.16 . PMC 3182497 . PMID 21427751 .
Weatherall DJ (May 2008). "Genetic variation and susceptibility to infection: the red cell and malaria" . British Journal of Haematology . 141 (3): 276–286. doi : 10.1111/j.1365-2141.2008.07085.x . PMID 18410566 . S2CID 28191911 .
Shelomi M, Zeuss D (5 April 2017). "Bergmann's and Allen's Rules in Native European and Mediterranean Phasmatodea" . Frontiers in Ecology and Evolution . 5 . doi : 10.3389/fevo.2017.00025 . hdl : 11858/00-001M-0000-002C-DD87-4 . ISSN 2296-701X . S2CID 34882477 .
Ilardo MA, Moltke I, Korneliussen TS, Cheng J, Stern AJ, Racimo F, et al. (April 2018). "Physiological and Genetic Adaptations to Diving in Sea Nomads" . Cell . 173 (3): 569–580.e15. doi : 10.1016/j.cell.2018.03.054 . PMID 29677510 .
Rogers AR, Iltis D, Wooding S (2004). "Genetic variation at the MC1R locus and the time since loss of human body hair". Current Anthropology . 45 (1): 105–08. doi : 10.1086/381006 . S2CID 224795768 .
Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 .
Jablonski NG, Chaplin G (May 2010). "Colloquium paper: human skin pigmentation as an adaptation to UV radiation" . Proceedings of the National Academy of Sciences of the United States of America . 107 (Supplement_2): 8962–8968. Bibcode : 2010PNAS..107.8962J . doi : 10.1073/pnas.0914628107 . PMC 3024016 . PMID 20445093 .
Jablonski NG, Chaplin G (July 2000). "The evolution of human skin coloration" (PDF) . Journal of Human Evolution . 39 (1): 57–106. doi : 10.1006/jhev.2000.0403 . PMID 10896812 . Archived from the original (PDF) on 14 January 2012.
Harding RM, Healy E, Ray AJ, Ellis NS, Flanagan N, Todd C, et al. (April 2000). "Evidence for variable selective pressures at MC1R" . American Journal of Human Genetics . 66 (4): 1351–1361. doi : 10.1086/302863 . PMC 1288200 . PMID 10733465 .
"The Science Behind the Human Genome Project" . Human Genome Project . US Department of Energy. Archived from the original on 2 January 2013 . Retrieved 6 January 2013 . Almost all (99.9%) nucleotide bases are exactly the same in all people.
O'Neil D. "Ethnicity and Race: Overview" . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 .
Keita SO, Kittles RA, Royal CD, Bonney GE, Furbert-Harris P, Dunston GM, Rotimi CN (November 2004). "Conceptualizing human variation" . Nature Genetics . 36 (11 Suppl): S17-20. doi : 10.1038/ng1455 . PMID 15507998 .
O'Neil D. "Models of Classification" . Modern Human Variation . Palomar College. Archived from the original on 6 January 2013 . Retrieved 6 January 2013 .
Jablonski N (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 .
Palmié S (May 2007). "Genomics, divination, 'racecraft' ". American Ethnologist . 34 (2): 205–222. doi : 10.1525/ae.2007.34.2.205 .
"Genetic – Understanding Human Genetic Variation" . Human Genetic Variation . National Institute of Health (NIH). Archived from the original on 25 August 2013 . Retrieved 13 December 2013 . In fact, research results consistently demonstrate that about 85 percent of all human genetic variation exists within human populations, whereas about only 15 percent of variation exists between populations.
Goodman A. "Interview with Alan Goodman" . Race Power of and Illusion . PBS. Archived from the original on 29 October 2012 . Retrieved 6 January 2013 .
Marks J (2010). "Ten facts about human variation". In Muehlenbein M (ed.). Human Evolutionary Biology (PDF) . New York: Cambridge University Press. Archived from the original (PDF) on 15 April 2012 . Retrieved 5 September 2013 .
Nina J (2004). "The evolution of human skin and skin color". Annual Review of Anthropology . 33 : 585–623. doi : 10.1146/annurev.anthro.33.070203.143955 . genetic evidence [demonstrate] that strong levels of natural selection acted about 1.2 mya to produce darkly pigmented skin in early members of the genus Homo
O'Neil D. "Overview" . Modern Human Variation . Palomar College. Archived from the original on 5 November 2012 . Retrieved 6 January 2013 .
Jorde LB, Watkins WS, Bamshad MJ, Dixon ME, Ricker CE, Seielstad MT, Batzer MA (March 2000). "The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data" . American Journal of Human Genetics . 66 (3): 979–988. doi : 10.1086/302825 . PMC 1288178 . PMID 10712212 .
"New Research Proves Single Origin Of Humans In Africa" . Science Daily . 19 July 2007. Archived from the original on 4 November 2011 . Retrieved 5 September 2011 .
Manica A, Amos W, Balloux F , Hanihara T (July 2007). "The effect of ancient population bottlenecks on human phenotypic variation" . Nature . 448 (7151): 346–348. Bibcode : 2007Natur.448..346M . doi : 10.1038/nature05951 . PMC 1978547 . PMID 17637668 .
Chen L, Wolf AB, Fu W, Li L, Akey JM (February 2020). "Identifying and Interpreting Apparent Neanderthal Ancestry in African Individuals" . Cell . 180 (4): 677–687.e16. doi : 10.1016/j.cell.2020.01.012 . PMID 32004458 . S2CID 210955842 .
Bergström A, McCarthy SA, Hui R, Almarri MA, Ayub Q, Danecek P, et al. (March 2020). "Insights into human genetic variation and population history from 929 diverse genomes" . Science . 367 (6484): eaay5012. doi : 10.1126/science.aay5012 . PMC 7115999 . PMID 32193295 . An analysis of archaic sequences in modern populations identifies ancestral genetic variation in African populations that likely predates modern humans and has been lost in most non-African populations.
Durvasula A, Sankararaman S (February 2020). "Recovering signals of ghost archaic introgression in African populations" . Science Advances . 6 (7): eaax5097. Bibcode : 2020SciA....6.5097D . doi : 10.1126/sciadv.aax5097 . PMC 7015685 . PMID 32095519 . Our analyses of site frequency spectra indicate that these populations derive 2 to 19% of their genetic ancestry from an archaic population that diverged before the split of Neanderthals and modern humans.
Pierce BA (2012). Genetics: A Conceptual Approach . Macmillan. p. 75. ISBN 978-1-4292-3252-4 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 .
Muehlenbein MP (29 July 2010). Jones J (ed.). Human Evolutionary Biology . Cambridge University Press. p. 74. ISBN 978-0-521-87948-4 . Retrieved 30 July 2022 .
Fusco G, Minelli A (10 October 2019). The Biology of Reproduction . Cambridge University Press. p. 304. ISBN 978-1-108-49985-9 . Archived from the original on 22 October 2022 . Retrieved 30 July 2022 .
Gustafsson A, Lindenfors P (October 2004). "Human size evolution: no evolutionary allometric relationship between male and female stature". Journal of Human Evolution . 47 (4): 253–266. doi : 10.1016/j.jhevol.2004.07.004 . PMID 15454336 .
Ogden CL, Fryar CD, Carroll MD, Flegal KM (October 2004). "Mean body weight, height, and body mass index, United States 1960–2002" (PDF) . Advance Data (347): 1–17. PMID 15544194 . Archived from the original (PDF) on 23 February 2011.
Miller AE, MacDougall JD, Tarnopolsky MA, Sale DG (1993). "Gender differences in strength and muscle fiber characteristics". European Journal of Applied Physiology and Occupational Physiology . 66 (3): 254–262. doi : 10.1007/BF00235103 . hdl : 11375/22586 . PMID 8477683 . S2CID 206772211 .
Bredella MA (2017). "Sex Differences in Body Composition". In Mauvais-Jarvis F (ed.). Sex and Gender Factors Affecting Metabolic Homeostasis, Diabetes and Obesity . Advances in Experimental Medicine and Biology. Vol. 1043. Cham: Springer International Publishing. pp. 9–27. doi : 10.1007/978-3-319-70178-3_2 . ISBN 978-3-319-70177-6 . PMID 29224088 .
Rahrovan S, Fanian F, Mehryan P, Humbert P, Firooz A (September 2018). "Male versus female skin: What dermatologists and cosmeticians should know" . International Journal of Women's Dermatology . 4 (3): 122–130. doi : 10.1016/j.ijwd.2018.03.002 . PMC 6116811 . PMID 30175213 .
Easter C. "Sex Linked" . National Human Genome Research Institute . Archived from the original on 14 April 2022 . Retrieved 18 April 2021 .
Puts DA, Gaulin SJ, Verdolini K (July 2006). "Dominance and the evolution of sexual dimorphism in human voice pitch". Evolution and Human Behavior . 27 (4): 283–296. doi : 10.1016/j.evolhumbehav.2005.11.003 . S2CID 32562654 .
Sax, Leonard (1 August 2002). "How common is lntersex? A response to Anne Fausto-Sterling" . The Journal of Sex Research . 39 (3): 174–178. doi : 10.1080/00224490209552139 . ISSN 0022-4499 . PMID 12476264 . S2CID 33795209 .
"3-D Brain Anatomy" . The Secret Life of the Brain . Public Broadcasting Service. Archived from the original on 5 September 2017 . Retrieved 3 April 2005 .
Stern P (22 June 2018). "The human prefrontal cortex is special" . Science . 360 (6395): 1311–1312. Bibcode : 2018Sci...360S1311S . doi : 10.1126/science.360.6395.1311-g . ISSN 0036-8075 . S2CID 149581944 .
Erickson R (22 September 2014). "Are Humans the Most Intelligent Species?" . Journal of Intelligence . 2 (3): 119–121. doi : 10.3390/jintelligence2030119 . ISSN 2079-3200 .
"Humans not smarter than animals, just different, experts say" . phys.org . Archived from the original on 30 January 2021 . Retrieved 24 October 2020 .
Robson D. "We've got human intelligence all wrong" . www.bbc.com . Archived from the original on 31 January 2021 . Retrieved 24 October 2020 .
Owen J (26 February 2015). "Many Animals – Including Your Dog – May Have Horrible Short-Term Memories" . National Geographic News . Archived from the original on 19 April 2021 . Retrieved 6 September 2020 .
Schmidt KL, Cohn JF (2001). "Human facial expressions as adaptations: Evolutionary questions in facial expression research" . American Journal of Physical Anthropology . 116 (S33): 3–24. doi : 10.1002/ajpa.20001 . PMC 2238342 . PMID 11786989 .
Moisse K (5 January 2011). "Tears in Her Eyes: A Turnoff for Guys?" . ABC News (American) . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 .
Deleniv S (2018). "The 'me' illusion: How your brain conjures up your sense of self" . New Scientist . Archived from the original on 18 February 2021 . Retrieved 22 April 2020 .
Beck J (2019). "Can We Really Know What Animals Are Thinking?" . Snopes . Archived from the original on 31 October 2021 . Retrieved 22 April 2020 .
Grandner MA, Patel NP, Gehrman PR, Perlis ML, Pack AI (August 2010). "Problems associated with short sleep: bridging the gap between laboratory and epidemiological studies" . Sleep Medicine Reviews . 14 (4): 239–247. doi : 10.1016/j.smrv.2009.08.001 . PMC 2888649 . PMID 19896872 .
Ann L (27 January 2005). "HowStuffWorks "Dreams: Stages of Sleep" " . Science.howstuffworks.com. Archived from the original on 15 May 2012 . Retrieved 11 August 2012 .
Hobson JA (November 2009). "REM sleep and dreaming: towards a theory of protoconsciousness". Nature Reviews. Neuroscience . 10 (11): 803–813. doi : 10.1038/nrn2716 . PMID 19794431 . S2CID 205505278 .
Lite J (29 July 2010). "How Can You Control Your Dreams?" . Scientific America . Archived from the original on 2 February 2015.
van Gulick R (2004). "Consciousness" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 14 October 2019 . Retrieved 30 July 2022 .
Schneider S, Velmans M (2008). "Introduction". In Velmans M, Schneider S (eds.). The Blackwell Companion to Consciousness . Wiley. ISBN 978-0-470-75145-9 .
Searle J (2005). "Consciousness". In Honderich T (ed.). The Oxford companion to philosophy . Oxford University Press. ISBN 978-0-19-926479-7 .
Block N (June 1995). "On a confusion about a function of consciousness" . Behavioral and Brain Sciences . 18 (2): 227–247. doi : 10.1017/S0140525X00038474 . S2CID 246244859 .
Jaynes J (2000) [1976]. The Origin of Consciousness in the Breakdown of the Bicameral Mind (PDF) . Houghton Mifflin. ISBN 0-618-05707-2 . Archived from the original (PDF) on 7 August 2019 . Retrieved 25 October 2020 .
Rochat P (December 2003). "Five levels of self-awareness as they unfold early in life". Consciousness and Cognition . 12 (4): 717–731. doi : 10.1016/s1053-8100(03)00081-3 . PMID 14656513 . S2CID 10241157 .
Carruthers P (15 August 2011). "Higher-Order Theories of Consciousness" . Stanford Encyclopedia of Philosophy . Archived from the original on 13 April 2021 . Retrieved 31 August 2014 .
"Cognition" . Lexico . Oxford University Press and Dictionary.com . Archived from the original on 8 July 2016 . Retrieved 6 May 2020 .
Glattfelder JB (2019). "The Consciousness of Reality". In Glattfelder JB (ed.). Information—Consciousness—Reality . The Frontiers Collection. Cham: Springer International Publishing. pp. 515–595. doi : 10.1007/978-3-030-03633-1_14 . ISBN 978-3-030-03633-1 . S2CID 189379814 .
"American Psychological Association (2013). Glossary of psychological terms" . Apa.org. Archived from the original on 8 July 2014 . Retrieved 13 August 2014 .
"Developmental Psychology Studies Human Development Across the Lifespan" . www.apa.org . Archived from the original on 9 July 2014 . Retrieved 28 August 2017 .
Colom R (1 January 2004). "Intelligence Assessment". Encyclopedia of Applied Psychology : 307–314. doi : 10.1016/B0-12-657410-3/00510-9 . ISBN 978-0-12-657410-4 .
McLeod S (20 March 2020). "Maslow's Hierarchy of Needs" . Simplypsychology.org . Simply Scholar Limited. Archived from the original on 8 November 2018 . Retrieved 4 April 2020 . Maslow's hierarchy of needs is a motivational theory in psychology comprising a five-tier model of human needs, often depicted as hierarchical levels within a pyramid. Needs lower down in the hierarchy must be satisfied before individuals can attend to needs higher up.
Heckhausen J, Heckhausen H (28 March 2018). "Motivation and Action: Introduction and Overview". Motivation and Action . Introduction and Overview: Springer, Cham. p. 1. doi : 10.1007/978-3-319-65094-4_1 . ISBN 978-3-319-65093-7 .
Damasio AR (May 1998). "Emotion in the perspective of an integrated nervous system". Brain Research. Brain Research Reviews . 26 (2–3): 83–86. doi : 10.1016/s0165-0173(97)00064-7 . PMID 9651488 . S2CID 8504450 .
Ekman P, Davidson RJ (1994). The Nature of emotion : fundamental questions . New York: Oxford University Press. pp. 291–293. ISBN 978-0-19-508944-8 . Emotional processing, but not emotions, can occur unconsciously.
Cabanac M (2002). "What is emotion?". Behavioural Processes . 60 (2): 69–83. doi : 10.1016/S0376-6357(02)00078-5 . PMID 12426062 . S2CID 24365776 . Emotion is any mental experience with high intensity and high hedonic content (pleasure/displeasure)
Averill JR (April 1999). "Individual differences in emotional creativity: structure and correlates". Journal of Personality . 67 (2): 331–371. doi : 10.1111/1467-6494.00058 . PMID 10202807 .
Tyng CM, Amin HU, Saad MN, Malik AS (2017). "The Influences of Emotion on Learning and Memory" . Frontiers in Psychology . 8 : 1454. doi : 10.3389/fpsyg.2017.01454 . PMC 5573739 . PMID 28883804 .
Van Gelder JL (November 2016). "Emotions in Criminal Decision Making". In Wright R (ed.). Oxford Bibliographies in Criminology . Oxford University Press. Archived from the original on 29 January 2021 . Retrieved 30 July 2022 .
Sharma N, Prakash O, Sengar KS, Chaudhury S, Singh AR (2015). "The relation between emotional intelligence and criminal behavior: A study among convicted criminals" . Industrial Psychiatry Journal . 24 (1): 54–58. doi : 10.4103/0972-6748.160934 . PMC 4525433 . PMID 26257484 .
Fredrickson BL (March 2001). "The role of positive emotions in positive psychology. The broaden-and-build theory of positive emotions" . The American Psychologist . 56 (3): 218–226. doi : 10.1037/0003-066X.56.3.218 . PMC 3122271 . PMID 11315248 .
Haybron DM (August 2013). "The proper pursuit of happiness". Res Philosophica . 90 (3): 387–411. doi : 10.11612/resphil.2013.90.3.5 .
Haybron DM (13 April 2014). "Happiness and Its Discontents" . The Opinion Pages . The New York Times. Archived from the original on 12 October 2018 . Retrieved 30 July 2022 . I would suggest that when we talk about happiness, we are actually referring, much of the time, to a complex emotional phenomenon. Call it emotional well-being. Happiness as emotional well-being concerns your emotions and moods, more broadly your emotional condition as a whole. To be happy is to inhabit a favorable emotional state.... On this view, we can think of happiness, loosely, as the opposite of anxiety and depression. Being in good spirits, quick to laugh and slow to anger, at peace and untroubled, confident and comfortable in your own skin, engaged, energetic and full of life.
Graham MC (2014). Facts of Life: ten issues of contentment . Outskirts Press. pp. 6–10. ISBN 978-1-4787-2259-5 .
"Secret to happiness may include more unpleasant emotions: Research contradicts idea that people should always seek pleasure to be happy" . ScienceDaily . American Psychological Association . 14 August 2017. Archived from the original on 11 November 2020 . Retrieved 25 October 2020 .
Greenberg JS, Bruess CE, Oswalt SB (2016). Exploring the Dimensions of Human Sexuality . Jones & Bartlett Publishers . pp. 4–10. ISBN 978-1-284-08154-1 . Retrieved 21 June 2017 . Human sexuality is a part of your total personality. It involves the interrelationship of biological, psychological, and sociocultural dimensions. [...] It is the total of our physical, emotional, and spiritual responses, thoughts, and feelings.
Bolin A, Whelehan P (2009). Human Sexuality: Biological, Psychological, and Cultural Perspectives . Taylor & Francis . pp. 32–42. ISBN 978-0-7890-2671-2 .
Younis I, Abdel-Rahman SH (2013). "Sex difference in libido". Human Andrology . 3 (4): 85–89. doi : 10.1097/01.XHA.0000432482.01760.b0 . S2CID 147235090 .
"Sexual orientation, homosexuality and bisexuality" . American Psychological Association . Archived from the original on 8 August 2013 . Retrieved 10 August 2013 .
Bailey JM, Vasey PL, Diamond LM, Breedlove SM, Vilain E, Epprecht M (September 2016). "Sexual Orientation, Controversy, and Science" . Psychological Science in the Public Interest . 17 (2): 45–101. doi : 10.1177/1529100616637616 . PMID 27113562 .
LeVay S (2017). Gay, Straight, and the Reason Why: The Science of Sexual Orientation . Oxford University Press. pp. 8, 19. ISBN 978-0-19-975296-6 . Retrieved 30 July 2022 .
Balthazart J (2012). The Biology of Homosexuality . Oxford University Press. pp. 13–14. ISBN 978-0-19-983882-0 . Retrieved 30 July 2022 .
Buss DM (2003). The Evolution of Desire: Strategies of Human Mating (Revised ed.). New York: Basic Books. ISBN 978-0-465-00802-5 .
"Love, Actually: The science behind lust, attraction, and companionship" . Science in the News . 14 February 2017. Archived from the original on 28 October 2020 . Retrieved 25 October 2020 .
"What are the top 200 most spoken languages?" . Ethnologue: Languages of the World . 2020. Archived from the original on 12 January 2013 . Retrieved 30 July 2022 .
World . The World Factbook (Report). Central Intelligence Agency . Archived from the original on 26 January 2021 . Retrieved 15 November 2021 .
"The Changing Global Religious Landscape" . Pew Research Center. 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 30 July 2022 .
Ord T (2020). The Precipice: Existential Risk and the Future of Humanity . New York: Hachette Books. ISBN 978-0-316-48489-3 . Homo sapiens and our close relatives may have some unique physical attributes, such as our dextrous hands, upright walking and resonant voices. However, these on their own cannot explain our success. They went together with our intelligence...
Goldman JG (2012). "Pay attention… time for lessons at animal school" . bbc.com . Archived from the original on 30 January 2021 . Retrieved 22 April 2020 .
Winkler M, Mueller JL, Friederici AD, Männel C (November 2018). "Infant cognition includes the potentially human-unique ability to encode embedding" . Science Advances . 4 (11): eaar8334. Bibcode : 2018SciA....4.8334W . doi : 10.1126/sciadv.aar8334 . PMC 6248967 . PMID 30474053 .
Johnson-Frey SH (July 2003). "What's so special about human tool use?" . Neuron . 39 (2): 201–204. doi : 10.1016/S0896-6273(03)00424-0 . PMID 12873378 . S2CID 18437970 .
Emery NJ, Clayton NS (February 2009). "Tool use and physical cognition in birds and mammals". Current Opinion in Neurobiology . 19 (1): 27–33. doi : 10.1016/j.conb.2009.02.003 . PMID 19328675 . S2CID 18277620 . In short, the evidence to date that animals have an understanding of folk physics is at best mixed.
Lemonick MD (3 June 2015). "Chimps Can't Cook, But Maybe They'd Like To" . National Geographic News . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 .
Vakhitova T, Gadelshina L (2 June 2015). "The Role and Importance of the Study of Economic Subjects in the Implementation of the Educational Potential of Education" . Procedia - Social and Behavioral Sciences . The Proceedings of 6th World Conference on educational Sciences. 191 : 2565–2567. doi : 10.1016/j.sbspro.2015.04.690 . ISSN 1877-0428 .
McKie R (9 October 2018). "The Book of Humans by Adam Rutherford review – a pithy homage to our species" . The Guardian . Archived from the original on 5 February 2021 . Retrieved 22 April 2020 .
Nicholls H (29 June 2015). "Babblers speak to the origin of language" . The Guardian . Archived from the original on 31 January 2021 . Retrieved 22 April 2020 .
Dasgupta S (2015). "Can any animals talk and use language like humans?" . bbc.com . Archived from the original on 2 May 2020 . Retrieved 22 April 2020 . Most animals are not vocal learners.
Scott-Phillips TC, Blythe RA (18 September 2013). "Why is language unique to humans?" . Royal Society. Archived from the original on 18 January 2021 . Retrieved 24 October 2020 .
Pagel M (July 2017). "Q&A: What is human language, when did it evolve and why should we care?" . BMC Biology . 15 (1): 64. doi : 10.1186/s12915-017-0405-3 . PMC 5525259 . PMID 28738867 .
Fitch WT (4 December 2010). "Language evolution: How to hear words long silenced". New Scientist . 208 (2789): ii–iii. Bibcode : 2010NewSc.208D...2F . doi : 10.1016/S0262-4079(10)62961-2 . ISSN 0262-4079 .
Lian A (2016). "The Modality-Independent Capacity of Language: A Milestone of Evolution". In Lian A (ed.). Language Evolution and Developmental Impairments . London: Palgrave Macmillan UK. pp. 229–255. doi : 10.1057/978-1-137-58746-6_7 . ISBN 978-1-137-58746-6 .
"Culture | United Nations For Indigenous Peoples" . www.un.org . 5 June 2015. Archived from the original on 26 November 2020 . Retrieved 24 October 2020 .
Comrie B, Polinsky M, Matthews S (1996). The Atlas of Languages: The Origin and Development of Languages Throughout the World . New York: Facts on File. pp. 13–15. ISBN 978-0-8160-3388-1 .
Mavrody S (2013). Visual Art Forms: Traditional to Digital . Sergey's HTML5 & CSS3. ISBN 978-0-9833867-5-9 . Retrieved 30 July 2022 .
"Types of Literary Arts and Their Understanding – bookfestivalscotland.com" . Bookfestival Scotland . 2020. Archived from the original on 5 May 2021 . Retrieved 5 May 2021 .
"Bachelor of Performing Arts" (PDF) . University of Otago . Archived (PDF) from the original on 14 December 2021 . Retrieved 30 July 2022 .
Brown S (24 October 2018). "Toward a Unification of the Arts" . Frontiers in Psychology . 9 : 1938. doi : 10.3389/fpsyg.2018.01938 . ISSN 1664-1078 . PMC 6207603 . PMID 30405470 .
"Culinary arts – How cooking can be an art" . Northern Contemporary Art . 21 October 2019. Archived from the original on 11 May 2021 . Retrieved 5 May 2021 .
Smuts A (1 January 2005). "Are Video Games Art?" . Contemporary Aesthetics (Journal Archive) . 3 (1). Archived from the original on 29 May 2022 . Retrieved 30 July 2022 .
Cameron IA, Pimlott N (September 2015). "Art of medicine" . Canadian Family Physician . 61 (9): 739–740. PMC 4569099 . PMID 26371092 .
Bird G (7 June 2019). "Rethinking the role of the arts in politics: lessons from the Négritude movement". International Journal of Cultural Policy . 25 (4): 458–470. doi : 10.1080/10286632.2017.1311328 . ISSN 1028-6632 . S2CID 151443044 .
Morriss-Kay GM (February 2010). "The evolution of human artistic creativity" . Journal of Anatomy . 216 (2): 158–176. doi : 10.1111/j.1469-7580.2009.01160.x . PMC 2815939 . PMID 19900185 .
Joordens JC, d'Errico F, Wesselingh FP, Munro S, de Vos J, Wallinga J, et al. (February 2015). "Homo erectus at Trinil on Java used shells for tool production and engraving". Nature . 518 (7538): 228–231. Bibcode : 2015Natur.518..228J . doi : 10.1038/nature13962 . PMID 25470048 . S2CID 4461751 .
St Fleur N (12 September 2018). "Oldest Known Drawing by Human Hands Discovered in South African Cave" . The New York Times . Archived from the original on 14 April 2020 . Retrieved 20 September 2018 .
Radford T (16 April 2004). "World's oldest jewellery found in cave" . The Guardian . ISSN 0261-3077 . Archived from the original on 12 February 2021 . Retrieved 23 September 2020 .
Dissanayake E (2008). "The Arts after Darwin: Does Art have an Origin and Adaptive Function?". In Zijlmans K, van Damme W (eds.). World Art Studies: Exploring Concepts and Approaches . Amsterdam: Valiz. pp. 241–263.
Morley I (2014). "A multi-disciplinary approach to the origins of music: perspectives from anthropology, archaeology, cognition and behaviour". Journal of Anthropological Sciences = Rivista di Antropologia . 92 (92): 147–177. doi : 10.4436/JASS.92008 (inactive 2024-03-20). PMID 25020016 . {{ cite journal }} : CS1 maint: DOI inactive as of March 2024 ( link )
Trost W, Frühholz S, Schön D, Labbé C, Pichon S, Grandjean D, Vuilleumier P (December 2014). "Getting the beat: entrainment of brain activity by musical rhythm and pleasantness" (PDF) . NeuroImage . 103 : 55–64. doi : 10.1016/j.neuroimage.2014.09.009 . PMID 25224999 . S2CID 4727529 .
Karpati FJ, Giacosa C, Foster NE, Penhune VB, Hyde KL (March 2015). "Dance and the brain: a review". Annals of the New York Academy of Sciences . 1337 (1): 140–146. Bibcode : 2015NYASA1337..140K . doi : 10.1111/nyas.12632 . PMID 25773628 . S2CID 206224849 .
Chow D (22 March 2010). "Why Do Humans Dance?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 21 September 2020 .
Krakauer J (26 September 2008). "Why do we like to dance – And move to the beat?" . Scientific American . Archived from the original on 28 February 2021 . Retrieved 21 September 2020 .
Prior KS (21 June 2013). "How Reading Makes Us More Human" . The Atlantic . Archived from the original on 29 January 2021 . Retrieved 23 September 2020 .
Puchner M. "How stories have shaped the world" . www.bbc.com . Archived from the original on 5 January 2021 . Retrieved 23 September 2020 .
Dalley, Stephanie , ed. (2000). Myths from Mesopotamia: Creation, the Flood, Gilgamesh, and Others (revised ed.). Oxford University Press. p. 41. ISBN 978-0-19-283589-5 .
Hernadi P (2001). "Literature and Evolution" . SubStance . 30 (1/2): 55–71. doi : 10.2307/3685504 . ISSN 0049-2426 . JSTOR 3685504 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 .
McCurry J (21 April 2015). "Japan's Maglev Train Breaks World Speed Record with 600 km/h Test Run" . The Guardian (U.S. ed.). New York. Archived from the original on 18 June 2022 . Retrieved 30 July 2022 .
Clark JD; de Heinzelin J ; Schick KD ; Hart WK; White TD ; WoldeGabriel G; Walter RC; Suwa G ; Asfaw B ; Vrba E ; H.-Selassie Y (June 1994). "African Homo erectus: old radiometric ages and young Oldowan assemblages in the Middle Awash Valley, Ethiopia". Science . 264 (5167): 1907–1910. Bibcode : 1994Sci...264.1907C . doi : 10.1126/science.8009220 . PMID 8009220 .
Choi CQ (11 November 2009). "Human Evolution: The Origin of Tool Use" . livescience.com . Archived from the original on 4 October 2020 . Retrieved 9 October 2020 .
Orban GA, Caruana F (2014). "The neural basis of human tool use" . Frontiers in Psychology . 5 : 310. doi : 10.3389/fpsyg.2014.00310 . PMC 3988392 . PMID 24782809 .
Berna F, Goldberg P, Horwitz LK, Brink J, Holt S, Bamford M, Chazan M (May 2012). "Microstratigraphic evidence of in situ fire in the Acheulean strata of Wonderwerk Cave, Northern Cape province, South Africa" . Proceedings of the National Academy of Sciences of the United States of America . 109 (20): E1215-20. doi : 10.1073/pnas.1117620109 . PMC 3356665 . PMID 22474385 .
Gowlett JA (June 2016). "The discovery of fire by humans: a long and convoluted process" . Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences . 371 (1696): 20150164. doi : 10.1098/rstb.2015.0164 . PMC 4874402 . PMID 27216521 .
Damiano J (2018). "Neolithic Era Tools: Inventing a New Age" . MagellanTV . Archived from the original on 5 January 2021 . Retrieved 9 October 2020 .
Deng Y, Wang P (2011). Ancient Chinese inventions . Cambridge, UK: Cambridge University Press. pp. 13–14. ISBN 978-0-521-18692-6 . OCLC 671710733 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Schifman J (9 July 2018). "The Entire History of Steel" . Popular Mechanics . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 .
Wilkinson, Freddie (9 January 2020). "Industrial Revolution and Technology" . National Geographic Society . Archived from the original on 30 September 2020 . Retrieved 9 October 2020 .
Roser, Max ; Ritchie, Hannah (11 May 2013). "Technological Progress" . Our World in Data . Archived from the original on 10 September 2021 . Retrieved 30 July 2022 .
Fallows J (23 October 2013). "The 50 Greatest Breakthroughs Since the Wheel" . The Atlantic . Archived from the original on 5 May 2021 . Retrieved 5 May 2021 .
Idinopulos TA (1998). "What Is Religion?" . CrossCurrents . 48 (3): 366–380. ISSN 0011-1953 . JSTOR 24460821 . Archived from the original on 13 October 2020 . Retrieved 30 July 2022 .
Emmons RA, Paloutzian RF (2003). "The psychology of religion". Annual Review of Psychology . 54 (1): 377–402. doi : 10.1146/annurev.psych.54.101601.145024 . PMID 12171998 .
King BJ (29 March 2016). "Chimpanzees: Spiritual But Not Religious?" . The Atlantic . Archived from the original on 20 January 2021 . Retrieved 8 October 2020 .
Ball P (2015). "Complex societies evolved without belief in all-powerful deity" . Nature News . doi : 10.1038/nature.2015.17040 . S2CID 183474917 . Archived from the original on 16 May 2021 . Retrieved 30 July 2022 .
Culotta E (November 2009). "Origins. On the origin of religion". Science . 326 (5954): 784–787. Bibcode : 2009Sci...326..784C . doi : 10.1126/science.326_784 . PMID 19892955 .
Atkinson QD, Bourrat P (2011). "Beliefs about God, the afterlife and morality support the role of supernatural policing in human cooperation" . Evolution and Human Behavior . 32 (1): 41–49. doi : 10.1016/j.evolhumbehav.2010.07.008 . ISSN 1090-5138 . Archived from the original on 15 October 2020 . Retrieved 30 July 2022 .
Walker GC (1 August 2000). "Secular Eschatology: Beliefs about Afterlife". OMEGA – Journal of Death and Dying . 41 (1): 5–22. doi : 10.2190/Q21C-5VED-GYW6-W091 . ISSN 0030-2228 . S2CID 145686249 .
McKay R, Whitehouse H (March 2015). "Religion and morality" . Psychological Bulletin . 141 (2): 447–473. doi : 10.1037/a0038455 . PMC 4345965 . PMID 25528346 .
Bernhard Nitsche; Marcus Schmücker, eds. (2023). God or the Divine? Religious Transcendence Beyond Monism and Theism, Between Personality and Impersonality . De Gruyter . doi : 10.1515/9783110698343 . ISBN 978-3-11-069834-3 .
Hall DE, Meador KG, Koenig HG (June 2008). "Measuring religiousness in health research: review and critique" . Journal of Religion and Health (Submitted manuscript). 47 (2): 134–163. doi : 10.1007/s10943-008-9165-2 . PMC 8823950 . PMID 19105008 . S2CID 25349208 . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 .
Sherwood H (27 August 2018). "Religion: why faith is becoming more and more popular" . The Guardian . ISSN 0261-3077 . Archived from the original on 1 March 2021 . Retrieved 8 October 2020 .
Hackett C, McClendon D (2017). "Christians remain world's largest religious group, but they are declining in Europe" . Pew Research Center . Archived from the original on 24 November 2019 . Retrieved 8 October 2020 .
"The Changing Global Religious Landscape" . Pew Research Center's Religion & Public Life Project . 5 April 2017. Archived from the original on 18 February 2022 . Retrieved 8 October 2020 .
Di Christina, Mariette (September 2018). "A Very Human Story: Why Our Species Is Special" . Scientific American . Archived from the original on 24 November 2020 . Retrieved 27 September 2020 .
Andersen H , Hepburn B (2020). "Scientific Method" . In Zalta EN (ed.). The Stanford Encyclopedia of Philosophy (Winter 2020 ed.). Metaphysics Research Lab, Stanford University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 .
Lo Presti R (2014). "History of science: The first scientist" . Nature . 512 (7514): 250–251. Bibcode : 2014Natur.512..250L . doi : 10.1038/512250a . ISSN 1476-4687 . S2CID 4394696 .
Russo L (2004). The forgotten revolution : how science was born in 300 BC and why it had to be reborn . Springer. p. 1. ISBN 978-3-642-18904-3 . OCLC 883392276 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Needham, J ; Wang Ling (1954). Science and civilisation in China . Cambridge University Press. p. 111. ISBN 0-521-05799-X . OCLC 779676 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Henry J (2008). "Renaissance and Revolution". The scientific revolution and the origins of modern science (3 ed.). Houndsmills, Basingstoke, Hampshire: Palgrave Macmillan. ISBN 978-1-137-07904-6 . OCLC 615209781 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
Hansson SO (2017). Zalta EN (ed.). "Science and Pseudo-Science" . Stanford Encyclopedia of Philosophy . Metaphysics Research Lab, Stanford University. Archived from the original on 11 June 2017 . Retrieved 3 July 2017 .
Olmstead MC, Kuhlmeier VA (2015). Comparative Cognition . Cambridge University Press. pp. 209–210. ISBN 978-1-107-01116-8 .
"Branches of Science" (PDF) . University of Chicago . Archived from the original (PDF) on 23 April 2017 . Retrieved 26 June 2017 .
"What is Philosophy?" . Department of Philosophy . Florida State University. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 .
"Philosophy" . Definition, Systems, Fields, Schools, & Biographies . Encyclopedia Britannica. Archived from the original on 23 February 2021 . Retrieved 8 October 2020 .
Kaufmann F, Russell B (1947). "A History of Western Philosophy and its Connection with Political and Social Circumstances from the Earliest Times to the Present Day" . Philosophy and Phenomenological Research . 7 (3): 461. doi : 10.2307/2102800 . JSTOR 2102800 . Archived from the original on 31 March 2022 . Retrieved 30 July 2022 .
Messerly JG (25 March 2016). "What is the Difference Between Philosophy, Science, and Religion?" . ieet.org . Archived from the original on 4 March 2021 . Retrieved 8 August 2020 .
Hassan NR, Mingers J, Stahl B (4 May 2018). "Philosophy and information systems: where are we and where should we go?" . European Journal of Information Systems . 27 (3): 263–277. doi : 10.1080/0960085X.2018.1470776 . hdl : 2086/16128 . ISSN 0960-085X . S2CID 64796132 .
Schizzerotto A. "Social Stratification" (PDF) . University of Trento . Archived from the original (PDF) on 20 March 2018 . Retrieved 3 July 2017 .
Fukuyama F (2012). The origins of political order : from prehuman times to the French Revolution . Farrar, Straus and Giroux. p. 53. ISBN 978-0-374-53322-9 . OCLC 1082411117 .
"Social Role Theory of Sex Differences and Similarities : A Current Appraisal" . The Developmental Social Psychology of Gender . Psychology Press. 2000. pp. 137–188. doi : 10.4324/9781410605245-12 . ISBN 978-1-4106-0524-5 . Archived from the original on 30 April 2021 . Retrieved 10 June 2022 .
Blackstone, Amy (2003). "Gender Roles and Society" . In Miller, Julia R.; Lerner, Richard M.; Schiamberg, Lawrence B. (eds.). Human Ecology: An Encyclopedia of Children, Families, Communities, and Environments . Sociology School Faculty Scholarship. Santa barbara, CA: ABC-CLIO. p. 335. Archived from the original on 16 May 2022 . Retrieved 30 July 2022 .
Nadal, Kevin L. (2017). The SAGE Encyclopedia of Psychology and Gender . SAGE Publications. p. 401. ISBN 978-1483384276 . Most cultures currently construct their societies based on the understanding of gender binary – the two gender categorizations (male and female). Such societies divide their population based on biological sex assigned to individuals at birth to begin the process of gender socialization.
Herdt, Gilbert (2020). "Third Sexes and Third Genders". Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . Princeton, NJ: Princeton University Press. pp. 21–83. ISBN 978-1-942130-52-9 . Retrieved 30 July 2022 .
Trumbach, Randolph (1994). "London's Sapphists: From Three Sexes to Four Genders in the Making of Modern Culture". In Herdt, Gilbert (ed.). Third Sex, Third Gender: Beyond Sexual Dimorphism in Culture and History . New York: Zone (MIT). pp. 111–136. ISBN 978-0-942299-82-3 .
Graham, Sharyn (April–June 2001). "Sulawesi's fifth gender" . Inside Indonesia . Archived from the original on 26 November 2014.
Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John ; Nieder, Timo O.; T'Sjoen, Guy (2016). "Non-binary or genderqueer genders" . International Review of Psychiatry . 28 (1): 95–102. doi : 10.3109/09540261.2015.1106446 . hdl : 1854/LU-7279758 . PMID 26753630 . S2CID 29985722 . Archived from the original on 26 June 2019 . Retrieved 9 June 2019 .
Ananthaswamy, Anil; Douglas, Kate. "The origins of sexism: How men came to rule 12,000 years ago" . New Scientist . Retrieved 7 March 2023 .
"What do we mean by "sex" and "gender"?" . World Health Organization . Archived from the original on 30 January 2017 . Retrieved 26 November 2015 .
Alters S, Schiff W (2009). Essential Concepts for Healthy Living . Jones & Bartlett Publishers . p. 143. ISBN 978-0-7637-5641-3 . Retrieved 3 January 2018 .
Fortin N (2005). "Gender Role Attitudes and the Labour Market Outcomes of Women Across OECD Countries". Oxford Review of Economic Policy . 21 (3): 416–438. doi : 10.1093/oxrep/gri024 .
Dobres, Marcia-Anne (27 November 2020). "Gender in the Earliest Human Societies" . In Meade, Teresa A.; Wiesner-Hanks, Merry E. (eds.). A Companion to Global Gender History (1 ed.). Wiley. pp. 183–204. doi : 10.1002/9781119535812.ch11 . ISBN 978-1-119-53580-5 . S2CID 229399965 . Archived from the original on 10 June 2022 . Retrieved 10 June 2022 .
"The Nature of Kinship: Overview" . www2.palomar.edu . Archived from the original on 3 December 2020 . Retrieved 24 October 2020 .
Itao K, Kaneko K (February 2020). "Evolution of kinship structures driven by marriage tie and competition" . Proceedings of the National Academy of Sciences of the United States of America . 117 (5): 2378–2384. Bibcode : 2020PNAS..117.2378I . doi : 10.1073/pnas.1917716117 . PMC 7007516 . PMID 31964846 .
Chandra, Kanchan (2012). Constructivist theories of ethnic politics . Oxford University Press. pp. 69–70. ISBN 978-0-19-989315-7 . OCLC 829678440 . Archived from the original on 30 July 2022 . Retrieved 30 July 2022 .
People J, Bailey G (2010). Humanity: An Introduction to Cultural Anthropology (9th ed.). Wadsworth Cengage learning. p. 389. In essence, an ethnic group is a named social category of people based on perceptions of shared social experience or one's ancestors' experiences. Members of the ethnic group see themselves as sharing cultural traditions and history that distinguish them from other groups. Ethnic group identity has a strong psychological or emotional component that divides the people of the world into opposing categories of 'us' and 'them.' In contrast to social stratification, which divides and unifies people along a series of horizontal axes based on socioeconomic factors, ethnic identities divide and unify people along a series of vertical axes. Thus, ethnic groups, at least theoretically, cut across socioeconomic class differences, drawing members from all strata of the population.
Blackmore E (22 February 2019). "Race and ethnicity: How are they different?" . Culture . Archived from the original on 22 October 2020 . Retrieved 24 October 2020 .
Chandra K (2006). "What is Ethnic Identity and Does It Matter?" . Annual Review of Political Science . 9 (1): 397–424. doi : 10.1146/annurev.polisci.9.062404.170715 . ISSN 1094-2939 .
Banton M (2007). "Max Weber on 'ethnic communities': a critique". Nations and Nationalism . 13 (1): 19–35. doi : 10.1111/j.1469-8129.2007.00271.x .
Delanty G, Kumar K (2006). The SAGE Handbook of Nations and Nationalism . London: Sage. p. 171. ISBN 978-1-4129-0101-7 .
Cronk L, Leech BL (20 September 2017). "How Did Humans Get So Good at Politics?" . SAPIENS . Archived from the original on 7 August 2020 . Retrieved 24 October 2020 .
Zmigrod L, Rentfrow PJ, Robbins TW (May 2018). "Cognitive underpinnings of nationalistic ideology in the context of Brexit" . Proceedings of the National Academy of Sciences of the United States of America . 115 (19): E4532–E4540. Bibcode : 2018PNAS..115E4532Z . doi : 10.1073/pnas.1708960115 . PMC 5948950 . PMID 29674447 . S2CID 4993139 .
Melina R (14 February 2011). "What Are the Different Types of Governments?" . livescience.com . Archived from the original on 1 February 2021 . Retrieved 24 October 2020 .
"Democracy Index 2021: less than half the world lives in a democracy" . The Economist Democracy Index . Economist Intelligence Unit . February 10, 2022.
Jeannie Evers (23 December 2012). "international organization" . National Geographic Society . Archived from the original on 27 April 2017 . Retrieved 24 October 2020 .
Horan RD, Bulte E, Shogren JF (1 September 2005). "How trade saved humanity from biological exclusion: an economic theory of Neanderthal extinction". Journal of Economic Behavior & Organization . 58 (1): 1–29. doi : 10.1016/j.jebo.2004.03.009 . ISSN 0167-2681 .
Gibbons J (11 August 2015). "Why did Neanderthals go extinct?" . Smithsonian Insider . Archived from the original on 12 November 2020 . Retrieved 11 October 2020 .
University of Wyoming (24 March 2005). "Did Use of Free Trade Cause Neanderthal Extinction?" . www.newswise.com . Archived from the original on 1 February 2021 . Retrieved 11 October 2020 .
Polianskaya A (15 March 2018). "Humans may have been trading with each for as long as 300,000 years" . inews.co.uk . Archived from the original on 23 January 2021 . Retrieved 11 October 2020 .
Henriques M. "How spices changed the ancient world" . www.bbc.com . Archived from the original on 25 January 2021 . Retrieved 11 October 2020 .
Strauss IE (26 February 2016). "The Myth of the Barter Economy" . The Atlantic . Archived from the original on 15 February 2021 . Retrieved 11 October 2020 .
"The History of Money" . www.pbs.org . 26 October 1996. Archived from the original on 29 November 2020 . Retrieved 11 October 2020 .
"Why do we need economists and the study of economics?" . Federal Reserve Bank of San Francisco . July 2000. Archived from the original on 12 November 2020 . Retrieved 23 October 2020 .
Sheskin M. "The inequality delusion: Why we've got the wealth gap all wrong" . New Scientist . Archived from the original on 3 February 2021 . Retrieved 24 October 2020 .
Yong E (28 September 2016). "Humans: Unusually Murderous Mammals, Typically Murderous Primates" . The Atlantic . Archived from the original on 7 May 2021 . Retrieved 7 May 2021 .
Gómez JM, Verdú M, González-Megías A, Méndez M (October 2016). "The phylogenetic roots of human lethal violence". Nature . 538 (7624): 233–237. Bibcode : 2016Natur.538..233G . doi : 10.1038/nature19758 . PMID 27680701 . S2CID 4454927 .
Pagel M (October 2016). "Animal behaviour: Lethal violence deep in the human lineage" (PDF) . Nature . 538 (7624): 180–181. Bibcode : 2016Natur.538..180P . doi : 10.1038/nature19474 . PMID 27680700 . S2CID 4459560 . Archived (PDF) from the original on 20 May 2022 . Retrieved 30 July 2022 .
Ferguson RB (1 September 2018). "War Is Not Part of Human Nature" . Scientific American . Archived from the original on 30 January 2021 . Retrieved 30 July 2022 .
Ferguson N (September–October 2006). "The Next War of the World" . Foreign Affairs . Archived from the original on 25 April 2022 . Retrieved 30 July 2022 .
Listen to this article ( 1 hour and 16 minutes ) This audio file was created from a revision of this article dated 11 January 2022 ( 2022-01-11 ) , and does not reflect subsequent edits. ( Audio help · More spoken articles )
This audio file was created from a revision of this article dated 11 January 2022 ( 2022-01-11 ) , and does not reflect subsequent edits.
v t e Human evolution Taxonomy ( Hominins ) Last common ancestors Chimpanzee–human Gorilla–human Orangutan–human Gibbon–human Australopithecines Nakalipithecus Orrorin Sahelanthropus Kenyanthropus Ardipithecus A. kadabba A. ramidus Australopithecus A. afarensis A. africanus A. anamensis A. bahrelghazali A. deyiremeda A. garhi A. sediba Paranthropus P. aethiopicus P. boisei P. robustus Humans and proto-humans ( Homo ) Proto-humans H. gautengensis (?) H. habilis H. naledi H. rudolfensis (?) H. tsaichangensis (?) Homo erectus H. e. erectus H. e. georgicus H. e. lantianensis H. e. nankinensis H. e. pekinensis H. e. soloensis H. e. tautavelensis H. e. yuanmouensis Archaic humans H. antecessor Denisovans H. ergaster (?) H. floresiensis H. heidelbergensis H. longi (?) H. luzonensis H. neanderthalensis H. rhodesiensis (?) Modern humans Homo sapiens H. s. sapiens (archaic homo sapiens, anatomically modern humans) Jebel Irhoud H. s. idaltu Cro-Magnon Manot people Tam Pa Ling Red Deer Cave people Ancestors Homo habilis → Homo ergaster / Homo erectus (→ Homo antecessor ) → Homo heidelbergensis → archaic Homo sapiens → Homo sapiens Models General models Hunting Gathering Endurance running Aquatic ape Sexual selection Self-domestication Specific models Diet Cooking Expensive tissue Shore-based Drugs Drunken monkey Evolutionary models of human drug use Stoned ape theory Behavior Killer ape Cooperative eye Life history Grandmother Patriarch Topics Bipedalism Skeleton Muscles Skin color Hair Thermoregulation Speech Language Intelligence Gender roles Origin of modern humans Recent African origin Multiregional origin Archaic admixture Behavioral modernity Early migrations Recent evolution Timelines Human evolution Human prehistory Human timeline Others Theorists Books Fossils Evolutionary anthropology Paleoanthropology Human evolutionary developmental biology Category Commons Evolutionary biology Portal
H. e. erectus H. e. georgicus H. e. lantianensis H. e. nankinensis H. e. pekinensis H. e. soloensis H. e. tautavelensis H. e. yuanmouensis
H. antecessor Denisovans H. ergaster (?) H. floresiensis H. heidelbergensis H. longi (?) H. luzonensis H. neanderthalensis H. rhodesiensis (?)
H. s. sapiens (archaic homo sapiens, anatomically modern humans) Jebel Irhoud H. s. idaltu Cro-Magnon Manot people Tam Pa Ling Red Deer Cave people
Homo habilis → Homo ergaster / Homo erectus (→ Homo antecessor ) → Homo heidelbergensis → archaic Homo sapiens → Homo sapiens
Diet Cooking Expensive tissue Shore-based Drugs Drunken monkey Evolutionary models of human drug use Stoned ape theory Behavior Killer ape Cooperative eye Life history Grandmother Patriarch
Recent African origin Multiregional origin Archaic admixture Behavioral modernity Early migrations Recent evolution
Theorists Books Fossils Evolutionary anthropology Paleoanthropology Human evolutionary developmental biology
v t e Extant species of family Hominidae (great apes) Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Suborder: Haplorhini Hominidae Ponginae Pongo (Orangutans) Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Homininae Gorilla (Gorillas) Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Hominini Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Homo (Humans) Human ( H. sapiens ) Category
v t e Apes Extant ape species Homo Human ( H. sapiens ) Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Gorilla Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Orangutan Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Gibbon ( family : Hylobatidae) Study of apes Great ape language Dian Fossey Birutė Galdikas Jane Goodall Chimpanzee genome project Human Genome Project Gladys Kalema-Zikusoka Neanderthal genome project Willie Smits Lone Drøscher Nielsen Ian Redmond Elgin Center Iowa Primate Learning Sanctuary Borneo Orangutan Survival Primate archaeology Legal and social status Personhood Research ban Kinshasa Declaration on Great Apes Great Ape Project Great Apes Survival Partnership International Primate Day Nonhuman Rights Project Related Primate List of individual apes (non-human) Apes in space (non-human) Bigfoot Bushmeat Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor Gibbon–human last common ancestor List of fictional primates (non-human) Great apes Human evolution Monkey Day Mythic humanoids Yeren Yeti Yowie Category
Homo Human ( H. sapiens ) Pan Bonobo ( P. paniscus ) Chimpanzee ( P. troglodytes ) Gorilla Eastern gorilla ( G. beringei ) Western gorilla ( G. gorilla ) Orangutan Sumatran orangutan ( P. abelii ) Bornean orangutan ( P. pygmaeus ) Tapanuli orangutan ( P. tapanuliensis ) Gibbon ( family : Hylobatidae)
Great ape language Dian Fossey Birutė Galdikas Jane Goodall Chimpanzee genome project Human Genome Project Gladys Kalema-Zikusoka Neanderthal genome project Willie Smits Lone Drøscher Nielsen Ian Redmond Elgin Center Iowa Primate Learning Sanctuary Borneo Orangutan Survival Primate archaeology
Personhood Research ban Kinshasa Declaration on Great Apes Great Ape Project Great Apes Survival Partnership International Primate Day Nonhuman Rights Project
Primate List of individual apes (non-human) Apes in space (non-human) Bigfoot Bushmeat Chimpanzee–human last common ancestor Gorilla–human last common ancestor Orangutan–human last common ancestor Gibbon–human last common ancestor List of fictional primates (non-human) Great apes Human evolution Monkey Day Mythic humanoids Yeren Yeti Yowie
Humans at Wikipedia's sister projects : Definitions from Wiktionary Media from Commons Quotations from Wikiquote Texts from Wikisource Taxa from Wikispecies
Taxon identifiers Homo sapiens Wikidata : Q15978631 ADW : Homo_sapiens BOLD : 12439 CoL : 6MB3T EoL : 327955 EPPO : HOMXSA GBIF : 2436436 iNaturalist : 43584 IRMNG : 10857762 ITIS : 180092 MDD : 1000718 MSW : 12100795 NBN : NHMSYS0000376773 NCBI : 9606 NZOR: d83185ac-1aa6-4f59-8645-fe8c040857b3 Observation.org : 83981 OBIS : 1455977 Open Tree of Life : 770315 Paleobiology Database : 83088 TSA : 8319 WoRMS : 1455977 ZooBank : 58D31D52-713D-44B4-9FE9-CB2D9249C422
Wikidata : Q15978631 ADW : Homo_sapiens BOLD : 12439 CoL : 6MB3T EoL : 327955 EPPO : HOMXSA GBIF : 2436436 iNaturalist : 43584 IRMNG : 10857762 ITIS : 180092 MDD : 1000718 MSW : 12100795 NBN : NHMSYS0000376773 NCBI : 9606 NZOR: d83185ac-1aa6-4f59-8645-fe8c040857b3 Observation.org : 83981 OBIS : 1455977 Open Tree of Life : 770315 Paleobiology Database : 83088 TSA : 8319 WoRMS : 1455977 ZooBank : 58D31D52-713D-44B4-9FE9-CB2D9249C422
Authority control databases International FAST National France BnF data Germany Israel Czech Republic Korea Other Encyclopedia of Modern Ukraine NARA İslâm Ansiklopedisi
Categories : Hominini Humans Apex predators Mammals described in 1758 Taxa named by Carl Linnaeus Tool-using mammals Cosmopolitan mammals Hidden categories: CS1 maint: DOI inactive as of March 2024 Articles with short description Short description is different from Wikidata Good articles Wikipedia indefinitely semi-protected pages Wikipedia indefinitely move-protected pages Articles with 'species' microformats Articles containing Latin-language text Articles containing Old French (842-ca. 1400)-language text Articles containing French-language text Articles containing potentially dated statements from 2018 All articles containing potentially dated statements Articles with hAudio microformats Spoken articles Pages using Sister project links with wikidata mismatch Pages using Sister project links with default search Taxonbars desynced from Wikidata Taxonbars on possible non-taxon pages Taxonbars with 20–24 taxon IDs Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with GND identifiers Articles with J9U identifiers Articles with NKC identifiers Articles with NLK identifiers Articles with EMU identifiers Articles with NARA identifiers Articles with TDVİA identifiers Articles containing video clips
Categories : Hominini Humans Apex predators Mammals described in 1758 Taxa named by Carl Linnaeus Tool-using mammals Cosmopolitan mammals
Hidden categories: CS1 maint: DOI inactive as of March 2024 Articles with short description Short description is different from Wikidata Good articles Wikipedia indefinitely semi-protected pages Wikipedia indefinitely move-protected pages Articles with 'species' microformats Articles containing Latin-language text Articles containing Old French (842-ca. 1400)-language text Articles containing French-language text Articles containing potentially dated statements from 2018 All articles containing potentially dated statements Articles with hAudio microformats Spoken articles Pages using Sister project links with wikidata mismatch Pages using Sister project links with default search Taxonbars desynced from Wikidata Taxonbars on possible non-taxon pages Taxonbars with 20–24 taxon IDs Articles with FAST identifiers Articles with BNF identifiers Articles with BNFdata identifiers Articles with GND identifiers Articles with J9U identifiers Articles with NKC identifiers Articles with NLK identifiers Articles with EMU identifiers Articles with NARA identifiers Articles with TDVİA identifiers Articles containing video clips
This page was last edited on 29 April 2024, at 05:20 (UTC) . Text is available under the Creative Commons Attribution-ShareAlike License 4.0 ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy . Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc. , a non-profit organization. Privacy policy About Wikipedia Disclaimers Contact Wikipedia Code of Conduct Developers Statistics Cookie statement Mobile view | biology | 84183 | https://no.wikipedia.org/wiki/Eksaptasjon | Eksaptasjon | Eksaptasjon (også kalt koopsjon eller preadaptasjon) er et begrep som betegner skifte i et trekk eller funksjon hos en levende organisme under evolusjon. Det innebærer at utviklingstrekk som primært hadde en eller flere bestemte definerte funksjoner etter hvert begynner å tjene nye funksjoner som følge av evolusjonær utvikling og seleksjon. Hos f.eks. hvaler er forlemmene som opprinnelig ble benyttet som bevegelsesorganer blitt omdannet til styringsmekanismer, og hos pattedyr er svettekjertler som tidligere kun skille ut svette blitt modifisert til melkekjertler som nærer avkommet.
Eksaptasjoner er vanlige i både anatomi og atferd. Fuglefjær er et klassisk eksempel: til å begynne med utviklet fjærene seg for temperaturregulering, men senere ble de tilpasset flyvning. Interessen for eksaptasjon gjelder både prosessen og produktet av evolusjonen: prosessen som skaper komplekse egenskaper og produktet som kan være ufullkommen utformet.
Referanser
Litteratur
Buss, David M., Martie G. Haselton, Todd K. Shackelford, et al. (1998) "Adaptations, Exaptations, and Spandrels," American Psychologist, 53 (May):533–548. http://www.sscnet.ucla.edu/comm/haselton/webdocs/spandrels.html
Darwin, Charles (1859) The Origin of Species, London, ch. 6, section "Modes of Transition." http://www.infidels.org/library/historical/charles_darwin/origin_of_species/Chapter6.html.
Ehrlich, Paul, and Marcus Feldman (2003) "Genes and Culture: What Creates Our Behavioral Phenome?," Current Anthropology, 44 (February):87–107. Included are comments and a reply.
Gould, Stephen Jay, and Elizabeth S. Vrba (1982), "Exaptation — a missing term in the science of form," Paleobiology 8 (1): 4–15.
Gould, Stephen Jay (1991) "Exaptation: A Crucial tool for Evolutionary Psychology," Journal of Social Issues 47: 43–65.
Jacob, Francois (1977) "Evolution and Tinkering," Science 196 (June 10): 1161–1166. [uid PubMed link]
MacDonald, Geoff, and Mark R. Leary (2005) "Why Does Social Exclusion Hurt? The Relationship between Social and Physical Pain," Psychological Bulletin 131 (2): 202–223.
Mayr, Ernst (1982) The Growth of Biological Thought: Diversity, Evolution, and Inheritance, Harvard University Press, ISBN 0-674-36445-7.
"Preadaptation." Merriam-Webster Online Dictionary. 2009. Merriam-Webster Online. 22 January 2009 <http://www.merriam-webster.com/dictionary/preadaptation>
Evolusjonsbiologi | norwegian_bokmål | 0.728272 |
yeast_dissolve_in_sugar/35CREAMpdf.txt | Practical technology from Lallemand Inc.
VOLUME 3/NUMBER 5
Cream Yeast
Cream Yeast
Calculations
The main difference between compressed
yeast and cream yeast is the solids content.
Compressed yeast solids vary between 28
and 35 percent yeast solids, including
residual salt and starch left over from the
filtration (de-watering) process. Cream
yeast solids typically vary between 14 and
20 percent yeast solids and do not contain
residual salt and starch. On an equal-solids
basis, cream yeast tends to perform better
than compressed because of higher specific
activity, greater consistency, and moreaccurate dosing. The performance advantage is not taken into account here, so the
following factors should be used as a starting point for optimization in the bakery.
Conversion ratios. The gassing power
of cream yeast is standardized by taking
into account the conversion ratio (w/w),
which is typically set at a value between
1.59 and 1.76. The lower conversion ratio
of, for example, 1.59 to 1 allows the bakery
to receive more compressed yeast equivalent pounds per truckload, allowing them
to hold more inventory per tank, thus
reducing the frequency of deliveries and
How to Evaluate a
Cream Yeast System
CREAM YEAST is a liquid form of
the compressed bakers yeast that’s
supplied in cakes and bags. The
use of cream yeast by larger bakeries in
North America is well established, and it
is expected that it will continue to grow.
A number of factors are involved in the
switch from compressed yeast to cream.
WORKING WITH CREAM YEAST
Cream yeast is usually shipped directly
from the yeast plant to the bakery once a
week. It is delivered cold in insulated tank
trucks and has a shelf life of about fourteen
days.
The new yeast is unloaded into one of
two storage tanks while the other tank
supplies yeast to the bakery. The two tanks
alternate so that when one is emptied it’s
cleaned and ready for the next delivery.
The storage tanks are refrigerated to about
36°F (2°C) and gently agitated to keep the
yeast homogeneous.
Cream yeast is continuously circulated
from the storage tank through a loop to the
dosing stations and back to the storage
tank. The quantity is metered into each
mixer. Each mixer has a control valve on
the control panel.
A clean-in-place (CIP) system is used to
keep the cream yeast equipment sanitary.
The cleaning solutions are prepared in their
own small tank, then circulated through
the lines and storage tanks. The receiving
line and storage tanks are cleaned after
each use without affecting the yeast distribution system, which is cleaned separately
in conjunction with the mixers.
A flow panel on the storage unit connects the different parts of the system to
receive, store, dispense, and clean. A control panel operates the electrical components and monitors their status.
COMPARING CREAM AND
COMPRESSED
Size and investment. Cream yeast systems
range in cost from less than $300,000 to
more than $600,000, depending on tank
size, number of dosing stations, and amount
of site preparation. Economies of scale mean
that larger systems cost less per pound of
yeast. Most systems have been installed in
Continued Continued
Storage
Tank
Storage
Tank
Tanker
Connection
RECEIVING LINE Dosing Stations
RECIRCULATION LOOP
Flow Panel
Control Panel
CIP
Tank
Refrigeration
Unit
SIMPLIFIED CREAM YEAST SYSTEM
CIP cycles. Both of these factors improve
the economics. Such lower conversion
ratios do place more pressure on the yeast
producer to maintain a higher performance quality and to maintain tighter controls during the separation stages of the
yeast.
System size and delivery frequency.
Both the conversion ratio and the density
(typically 8.8 pounds per gallon) of the
cream yeast have to be taken into account
when converting pounds of compressed
yeast into gallons of cream yeast. To convert pounds of compressed yeast into gallons of cream yeast, multiply by 0.18 for a
1.59 conversion ratio and 0.20 for a 1.76
conversion ratio. A bakery using 25,000
pounds of compressed yeast would use
4,500 gallons of cream yeast with a 1.59
conversion ratio. This means that given a
delivery of 6,000 U.S. gallons of cream
yeast, this bakery would need delivery
every 9.3 days.
Formula adjustments. To switch from
compressed to cream yeast (with a 1.59
conversion ratio), the baker would replace
1 pound of compressed yeast with 1.59
pounds of cream yeast and deduct 0.59
pounds of water from the dough formula.
Cream Yeast Calculations (Continued)
IMPROVED YEAST QUALITY
• Cream yeast requires fewer processing
steps and is generally fresher
• Hygiene and cleanliness are enhanced
due to system design and CIP cleaning
process
• System provides excellent storage temperature control
• Cream yeast leaves the factory in perfect
condition and at the correct temperature
• The closed system from point of manufacture through delivery and use ensures
hygiene without human handling
ACCURACY OF DOSING
• Yeast is dosed into the mixer bowl using
a highly accurate flow meter
BETTER YEAST UTILIZATION
• More consistent gassing performance
• More accurate dosing at the mixer
LABOR SAVINGS
• Eliminates double handling
• No unwrapping and scaling
• No need to dispose of used packaging
How to Evaluate a
Cream Yeast System
(Continued)
bakeries using 25,000 pounds or more of
compressed yeast per week.
Space and location. Cream yeast storage units can be installed inside or outside
but should be close to mixers, utilities, and
the tanker connection. This is easier to
accommodate in new bakeries during the
design phase.
Performance and quality. Cream yeast
has a performance advantage because of
more-consistent activity and more-accurate
dosing. It has a sanitation advantage because it’s handled in a closed system with
better temperature control and a lower risk
of contamination.
Operating costs.Cream yeast avoids the
labor, maintenance, and electrical costs of
refrigerated storage for compressed yeast.
The system requires trained labor, maintenance, and electrical costs of its own.
Health, safety, and environment.
Cream yeast systems eliminate worker injuries from box and bag handling. They
avoid the solid waste disposal problem of
compressed yeast but use water and generate wastewater.
L
ALLEMAND was the pioneer beginning in 1980 for liquid cream yeast
systems for the North American
baking industry, and remains a leader in this
segment with more than a hundred systems
currently operating in North America.
American Yeast, Lallemand, and Eagle®
bulk liquid yeast systems are supplied from
one of the yeast plants, whether it be
Bakersfield, California, Baltimore, Maryland, Memphis, Tennessee, or Montréal,
Canada.
Introducing a liquid cream yeast system starts with a site survey at the bakery
and a complete analysis of the mechanical,
electrical, civil, operational, and general
requirements. This survey is used to prepare a proposal that includes a design of
the installation. While the proposal is
being prepared, a portable unit can be used
at the bakery to confirm performance and
cost calculations.
The liquid cream yeast system is
designed to prevent mistakes that could
cause contamination or loss of yeast. It
includes backup systems for critical elements such as the refrigeration unit. And,
it uses bakery-proven components at the
mixing stations.
The liquid cream yeast is standardized
by volume using computerized gassing tests
and density measurements to give consistent baking performance.
Lallemand/American Yeast provides
complete engineering, contracting, and
start-up for a turnkey operation. This includes operating and maintenance manuals and training for the bakery production,
maintenance, and sanitation personnel.
Local engineering support and technical
service are on-call at all times.
Lallemand Cream Yeast Systems
ADVANTAGES OF CREAM YEAST
Lallemand Baking Update is produced by
Lallemand Inc. to provide bakers with a
source of practical technology for solving
problems. You can find the latest issues
online at www.lallemandbaking.com.
If you have questions or comments,
please contact us at:
LALLEMAND Inc.
1620 Préfontaine
Montréal, QC H1W 2N8 Canada
tel: (800) 840-4047 (514) 522-2133
email: [email protected]
www.lallemand.com
To the best of our knowledge, the information in
Lallemand Baking Update is true and accurate. However, any recommendations or suggestions are made
without warranty or guarantee.
© 2018 Lallemand Inc.
| biology | 1775398 | https://no.wikipedia.org/wiki/IBC%20%28standard%29 | IBC (standard) | IBC (engelsk Intermediate Bulk Container, «mellomstor beholder») er en standard for gjenbrukbare beholdere til industriell bruk for å oppbevare og transportere væsker, semifaste stoffer, pastaer eller faste stoffer. IBC-kontainere kan deles i de to hovedkategoriene stive IBC-kontainere («IBC-tanker») og tøyelige IBC-kontainere («IBC-poser»).
IBC-tanker
IBC-tanker er allsidige og gjenbrukbare beholdere som kan stables, samt har integrert pallebase slik at de enkelt kan flyttes med gaffeltruck og/eller jekketralle. IBC-beholdere er gjerne laget av metall, plast eller kompositter.
Med IBC-tanker mener man gjerne tanker med volum som ligger i området mellom vanlige fat/tønne (typisk 200 liter) og opp til tankkontainere (starter rundt liter), derav navnet «mellomstor beholder». En fordel med firkantede IBC-tanker er at de kan stables mye mer effektivt enn med sylindriske tanker. Amerikanske myndigheter definerer IBC-kontainere til å ha volum mellom 416 til 3002 liter (110 til 793 US gallon). De vanligste volumene som sees på IBC-kontainere er mellom 1000 til 1250 liter.
IBC-tanker lages i ulike materialer ut ifra på bruksområde. Noen vanlige materialkombinasjoner er:
Plast (høytetthets-polyetylen)
Kombi: Bur av galvanisert stål og flaske av plast
Karbonstål
Rustfritt stål (A2 / 304)
Syrefast stål (A4 / 316L)
Den mest brukte og mest kjente typen IBC-tanker er kombivarianten med begrenset gjenbruk. Disse tankene består av en hvit/gjennomsiktig plastbeholder (høytetthets-polyetylen, HDPE) med et beskyttende bur av bestående av rør i galvanisert stål montert i rutenett. Denne typen er ofte brukt på grunn av lave kostnader og høy grad av allsidighet.
Oppbygning
De fleste IBC-kontainere er kubeformet, hvilket tillater effektiv stabling og plassutnyttelse under lagring og transport.
Stive IBC-kontainere har integrerte pallebaser, ofte med utvendige mål rundt 1200 x 1000 mm. IBC-kontainere er designet for å kuunne flyttes med gaffeltruck eller jekketralle. Så godt som alle stive IBC-kontainere er utformet slik at de kan stables oppå hverandre ved hjelp av gaffeltruck. De fleste stice IBC-kontainere har innebygd tappekran eller ventil i bunnen av beholderen hvor man kan feste slanger eller helle innholdet over i mindre beholdere.
En vanlig base-dimensjon er 1100 x 1100 mm. Sammenlignet med tønner kan man transportere høyere volum med IBC-tanker på mindre plass. For eksempel har en 1000 liters IBC-tank omtrent like mye volum som fem 210-liters tønner (1050 liter), mens en enkelt 1200 liters IBC-tank har omtrent like mye volum som seks 210-liters tønner (1260 liter). IBC-tankene vil imidlertid bare oppta én enkelt pall hver.
Bruk
IBC-tanker brukes blant annet til:
Kjemikalier, inkludert farlig gods
Varer og råvarer brukt i industriell produksjon
Flytende, granulerte og pulveriserte ingredienser til matvarer
Ulike typer sirup, som for eksempel maissirup, lønnesirup eller melasse
Petrokjemiske produkter, som olje, bensin, løsemidler, rengjøringsmidler eller klebemidler
Oppsamling av regnvann
IBC-tanker er en viktig komponent i mange hjemmelagde systemer for akvaponikk.
Maling og midler til industriell overflatebehandling
Farmasøytiske forbindelser, råvarer, mellomprodukter, batch-produkter
Helserelaterte artikler, bioavfall, avfallsstoffer
Vingårder, vingjæring, spritproduksjon
Jordbruk, drivhus og kjemikalier
Mange bruksområder for vann, avløp og prosessvann i ulike industrielle sektorer
Kjøp og salg
IBC-tanker omsettes hovedsakelig på tre måter:
Ny flaske og nytt bur.
Ny flaske, men vasket bur.
Både vasket flaske og vasket bur.
En helt ny enhet er vanligvis dyrest, mens en komplett vasket enhet som regel er rimeligst. Valget avhenger mye av hvor stor renhet som kreves, hva som tidligere har vært på beholderen og hvor enkelt det er å rense en flaske.
IBC-tanker kan leies i en såkalt «lukket sløyfe» hvor man er låst til en leverandør som både leverer ut og tar imot for vask og bytte av flaske. Det mest vanlige er imidlertid «åpen sløyfe» hvor man er fleksibel på opprinnelse og hvor flasker vaskes og byttes.
IBC-poser
Fleksible IBC-kontainere («IBC-poser») brukes blant annet for lagring og transport av tørre og flytende produkter som for sand, gjødsel, og plastgranulat. En vanlig IBC-pose kan typisk løfte en masse mellom 500–1000 kg, med volum mellom 250-3000 liter. Vanlige plastmaterialer for konstruksjon av fleksible IBC-kontainere er vevd polyetylen eller polypropylen. IBC-poser kan også bestå av materialer som trefiberplater, treverk eller aluminium. Ettersom tøyelige kontainere kan brettes når de er tomme tar de opp mye mindre plass under lagring og når de må sendes tomme (som for eksempel under returtransport).
Se også
Jerrykanne
Vanndunk
Referanser
Beholdere | norwegian_bokmål | 0.799435 |
yeast_dissolve_in_sugar/sffactivitysugarandy.txt | Food Science Sugar Yeast Fermentation
Science Film Festival Films
nine-and-a-half at Planet School:
Sugar-free Sweets – Snacking with no End?
Learning Goals
• To describe the properties and affects of yeast.
• To understand that the reaction of yeast with sugar will produce carbon dioxide.
• To understand that every organism needs sugar to survive and to generate energy
(some organism don’t need oxygen, but still need sugar).
• To understand that sugar produces energy, but that we need to control the quantity of
sugar that we absorb into the body. People should be eating healthier with foods that
contain less sugar.
Explanation of Scientific Principles
Yeast is a single-cell microorganism. The yeast in the bread that we eat every day is
prebiotic, it is not the powder (for example baking soda or baking powder) like people
sometimes think. Sugar is nutrition for yeast, it consumes it and produces CO2. Yeasts
produces enzymes that react with sugar. The yeasts, like most fungi, respires oxygen
(aerobic respiration), but in the absence of air they derive energy by fermenting sugars
and carbohydrates to produce ethanol and carbon dioxide.
Yeast fermentations have for millennia provided us with a variety of biotech products,
like wine, beer, vitamins, and recently also with pharmaceutically active heterologous
products and biofuels. A central biochemical activity in the yeast cell is the metabolism
of carbon compounds, providing energy for the whole cell, and precursors for any of the
final fermentation products.
Explanation of Connection to the Film
In the film, sugar is covered with many interesting facts, such as that there is more than
one kind of sugar. Some types of sugar are good for our health, but other types can be
harmful to us. However, the film shows that sugar is energy for every organism and
it is important for the process of transforming food into energy. The presenter did an
experiment to show us how bacteria “eat” sugar to then produce energy. This experiment
with yeast, demonstrates the same principle as the one in the film.
Materials
•teaspoon of baker’s yeast
• 10 teaspoons of sugar
•4 glasses or glass bottles
•4 balloon
•Water
Sugar & Yeast
Preparation
Pour yeast in half of the
glass water.
Place the balloon on the
edge of the glass and wait
about 8 minutes to see
the result.
Pour about 3 teaspoons
sugar into the solution.
While awaiting the result,
the facilitator can conduct
the following activities:
Prepare 10-20 bags
of sugar (each bag
containing 10g of
sugar) and the labels
from various soft
drinks (Coke, Fanta,
juices, water)
Arrange the quantity
of sugar by reading
the information on
the label (or you can
use the content from
the chart below)
1
3
2
4
a
b
www.neeldentistry.com/progress/how-much-sugar-is-in-your-drink/attachment/how-much-sugar-in-drinks/
www.youtube.com/watch?v=qoxY0z8ukUQ
web.archive.org/web/20090226151906/http://www.yeastgenome.org/VL-what_are_yeast.html
www.rethinksugarydrink.org.au/how-much-sugar
Main Menu
How much sugar is in ...?
Drink Serving
size
Sugar
per serve
(g)
Sugar per
serve
(tsp)
Sugar
per
100mL (g)
Sugar per
100mL
(tsp)
Soft drinks
Solo 600mL 69 17.3 11.5 2.9
Coca Cola 600mL 64 16.0 10.6 2.7
Sprite 600mL 52 13.0 8.6 2.2
Fanta 375mL 41 10.3 10.9 2.7
Bundaberg: Ginger
Beer 375mL 40.5 10.1 10.8 2.7
Coca Cola 375mL 40 10.0 10.6 2.7
Energy drinks
Rockstar: Super Sours
Energy Drink 500mL 67 16.8 13 3.3
V Energy Drink 500mL 53 13.3 10.6 2.7
Mother 500mL 51 12.8 10.1 2.5
Red Bull 250mL 27 6.8 11 2.8
Sports drinks
Gatorade: Fierce
Grape flavour 600mL 36 9.0 5.5 1.4
Gatorade: Tropical 600mL 36 9.0 6 1.5
Powerade: Mountain
Blast flavour 600mL 35 8.8 5.8 1.5
Powerade: Lemon
lime 600mL 35 8.8 5.8 1.5
Other drinks
Lipton Ice Tea: Peach
flavour 500mL 26.4 6.6 5.3 1.3
Glacier Vitamin water:
kiwi strawberry flavour 500mL 22 5.5 4.3 1.1
Sugar & Yeast | biology | 1560499 | https://sv.wikipedia.org/wiki/2-Naftol | 2-Naftol | 2-Naftol är ett färglöst, sidenglänsande, kristallinskt ämne, eller ett kristallinskt pulver med svag lukt och brännande smak. Det är svårlösligt i vatten, men lättlösligt i eter, kloroform, alkohol och i feta oljor.
Det löses även i alkalihydroxidlösningar under bildande av salter. Blandas en mättad lösning med lika volym ammoniak erhåller vätskan en svag, blåaktig fluorescens.
Genom tillsats av järnklorid till en vattenlösning av 2-naftol antar denna en grönaktig färg som försvinner efter en tid och en vit fällning uppstår.
Ämnet är en isomer av 1-naftol med skillnad i hydroxylgruppens placering på naftalen.
Framställning
2-Naftol framställs genom inverkan av koncentrerad svavelsyra på naftalen vid en temperatur av 200 °C, varvid 2-naftalensulfonsyra erhålls, som behandlad med natriumhydroxid ger naftolnatrium ur vilken 2-naftol frigörs med saltsyra.
Användning
2-Naftol är en viktig mellanprodukt vid tillverkning av s.k. naftolfärgämnen, som används inom bomullsfärgerier och har hög färgäkthet.
2-Naftol har också användning inom medicinen.
Källor
Meyers varulexikon, Forum, 1952
Naftoler | swedish | 1.109241 |
yeast_dissolve_in_sugar/Osmosis.txt |
Osmosis (/ɒzˈmoʊsɪs/, US also /ɒs-/) is the spontaneous net movement or diffusion of solvent molecules through a selectively-permeable membrane from a region of high water potential (region of lower solute concentration) to a region of low water potential (region of higher solute concentration), in the direction that tends to equalize the solute concentrations on the two sides. It may also be used to describe a physical process in which any solvent moves across a selectively permeable membrane (permeable to the solvent, but not the solute) separating two solutions of different concentrations. Osmosis can be made to do work. Osmotic pressure is defined as the external pressure required to be applied so that there is no net movement of solvent across the membrane. Osmotic pressure is a colligative property, meaning that the osmotic pressure depends on the molar concentration of the solute but not on its identity.
Osmosis is a vital process in biological systems, as biological membranes are semipermeable. In general, these membranes are impermeable to large and polar molecules, such as ions, proteins, and polysaccharides, while being permeable to non-polar or hydrophobic molecules like lipids as well as to small molecules like oxygen, carbon dioxide, nitrogen, and nitric oxide. Permeability depends on solubility, charge, or chemistry, as well as solute size. Water molecules travel through the plasma membrane, tonoplast membrane (vacuole) or organelle membranes by diffusing across the phospholipid bilayer via aquaporins (small transmembrane proteins similar to those responsible for facilitated diffusion and ion channels). Osmosis provides the primary means by which water is transported into and out of cells. The turgor pressure of a cell is largely maintained by osmosis across the cell membrane between the cell interior and its relatively hypotonic environment.
History
The "endosmometer" invented by Dutrochet
Some kinds of osmotic flow have been observed since ancient times, e.g., on the construction of Egyptian pyramids. Jean-Antoine Nollet first documented observation of osmosis in 1748. The word "osmosis" descends from the words "endosmose" and "exosmose", which were coined by French physician René Joachim Henri Dutrochet (1776–1847) from the Greek words ἔνδον (éndon "within"), ἔξω (éxō "outer, external"), and ὠσμός (ōsmós "push, impulsion"). In 1867, Moritz Traube invented highly selective precipitation membranes, advancing the art and technique of measurement of osmotic flow.
Description
Osmosis is the movement of a solvent across a semipermeable membrane toward a higher concentration of solute. In biological systems, the solvent is typically water, but osmosis can occur in other liquids, supercritical liquids, and even gases.
When a cell is submerged in water, the water molecules pass through the cell membrane from an area of low solute concentration to high solute concentration. For example, if the cell is submerged in saltwater, water molecules move out of the cell. If a cell is submerged in freshwater, water molecules move into the cell.
Water passing through a semipermeable membrane
When the membrane has a volume of pure water on both sides, water molecules pass in and out in each direction at exactly the same rate. There is no net flow of water through the membrane.
Osmosis can be demonstrated when potato slices are added to a high salt solution. The water from inside the potato moves out to the solution, causing the potato to shrink and to lose its 'turgor pressure'. The more concentrated the salt solution, the bigger the loss in size and weight of the potato slice.
Chemical gardens demonstrate the effect of osmosis in inorganic chemistry.
Mechanism
The mechanism responsible for driving osmosis has commonly been represented in biology and chemistry texts as either the dilution of water by solute (resulting in lower concentration of water on the higher solute concentration side of the membrane and therefore a diffusion of water along a concentration gradient) or by a solute's attraction to water (resulting in less free water on the higher solute concentration side of the membrane and therefore net movement of water toward the solute). Both of these notions have been conclusively refuted.
The diffusion model of osmosis is rendered untenable by the fact that osmosis can drive water across a membrane toward a higher concentration of water. The "bound water" model is refuted by the fact that osmosis is independent of the size of the solute molecules—a colligative property—or how hydrophilic they are.
It is difficult to describe osmosis without a mechanical or thermodynamic explanation, but essentially there is an interaction between the solute and water that counteracts the pressure that otherwise free solute molecules would exert. One fact to take note of is that heat from the surroundings is able to be converted into mechanical energy (water rising).
Many thermodynamic explanations go into the concept of chemical potential and how the function of the water on the solution side differs from that of pure water due to the higher pressure and the presence of the solute counteracting such that the chemical potential remains unchanged. The virial theorem demonstrates that attraction between the molecules (water and solute) reduces the pressure, and thus the pressure exerted by water molecules on each other in solution is less than in pure water, allowing pure water to "force" the solution until the pressure reaches equilibrium.
Role in living things
Effect of different solutions on blood cellsMicrographs of osmotic pressure on red blood cells (RBC)Plant cell in different environments.
Osmotic pressure is the main agent of support in many plants. The osmotic entry of water raises the turgor pressure exerted against the cell wall, until it equals the osmotic pressure, creating a steady state.
When a plant cell is placed in a solution that is hypertonic relative to the cytoplasm, water moves out of the cell and the cell shrinks. In doing so, the cell becomes flaccid. In extreme cases, the cell becomes plasmolyzed – the cell membrane disengages with the cell wall due to lack of water pressure on it.
When a plant cell is placed in a solution that is hypotonic relative to the cytoplasm, water moves into the cell and the cell swells to become turgid.
Osmosis also plays a vital role in human cells by facilitating the movement of water across cell membranes. This process is crucial for maintaining proper cell hydration, as cells can be sensitive to dehydration or overhydration. In human cells, osmosis is essential for maintaining the balance of water and solutes, ensuring optimal cellular function. Imbalances in osmotic pressure can lead to cellular dysfunction, highlighting the importance of osmosis in sustaining the health and integrity of human cells.
In certain environments, osmosis can be harmful to organisms. Freshwater and saltwater aquarium fish, for example, will quickly die should they be placed in water of a maladaptive salinity. The osmotic effect of table salt to kill leeches and slugs is another example of a way osmosis can cause harm to organisms.
Suppose an animal or plant cell is placed in a solution of sugar or salt in water.
If the medium is hypotonic relative to the cell cytoplasm, the cell will gain water through osmosis.
If the medium is isotonic, there will be no net movement of water across the cell membrane.
If the medium is hypertonic relative to the cell cytoplasm, the cell will lose water by osmosis.
This means that if a cell is put in a solution which has a solute concentration higher than its own, it will shrivel, and if it is put in a solution with a lower solute concentration than its own, the cell will swell and may even burst.
Factors
This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: "Osmosis" – news · newspapers · books · scholar · JSTOR (March 2024) (Learn how and when to remove this template message)
Osmotic pressure
Main article: Osmotic pressure
Osmosis may be opposed by increasing the pressure in the region of high solute concentration with respect to that in the low solute concentration region. The force per unit area, or pressure, required to prevent the passage of water (or any other high-liquidity solution) through a selectively permeable membrane and into a solution of greater concentration is equivalent to the osmotic pressure of the solution, or turgor. Osmotic pressure is a colligative property, meaning that the property depends on the concentration of the solute, but not on its content or chemical identity.
Osmotic gradient
The osmotic gradient is the difference in concentration between two solutions on either side of a semipermeable membrane, and is used to tell the difference in percentages of the concentration of a specific particle dissolved in a solution.
Usually the osmotic gradient is used while comparing solutions that have a semipermeable membrane between them allowing water to diffuse between the two solutions, toward the hypertonic solution (the solution with the higher concentration). Eventually, the force of the column of water on the hypertonic side of the semipermeable membrane will equal the force of diffusion on the hypotonic (the side with a lesser concentration) side, creating equilibrium. When equilibrium is reached, water continues to flow, but it flows both ways in equal amounts as well as force, therefore stabilizing the solution.
Variation
Reverse osmosis
Main article: Reverse osmosis
Reverse osmosis is a separation process that uses pressure to force a solvent through a semi-permeable membrane that retains the solute on one side and allows the pure solvent to pass to the other side, forcing it from a region of high solute concentration through a membrane to a region of low solute concentration by applying a pressure in excess of the osmotic pressure. This process is known primarily for its role in turning seawater into drinking water, when salt and other unwanted substances are ridded from the water molecules.
Forward osmosis
Main article: Forward osmosis
Osmosis may be used directly to achieve separation of water from a solution containing unwanted solutes. A "draw" solution of higher osmotic pressure than the feed solution is used to induce a net flow of water through a semi-permeable membrane, such that the feed solution becomes concentrated as the draw solution becomes dilute. The diluted draw solution may then be used directly (as with an ingestible solute like glucose), or sent to a secondary separation process for the removal of the draw solute. This secondary separation can be more efficient than a reverse osmosis process would be alone, depending on the draw solute used and the feedwater treated. Forward osmosis is an area of ongoing research, focusing on applications in desalination, water purification, water treatment, food processing, and other areas of study.
Future developments in osmosis
Future developments in osmosis and osmosis research hold promise for a range of applications. Researchers are exploring advanced materials for more efficient osmotic processes, leading to improved water desalination and purification technologies. Additionally, the integration of osmotic power generation, where the osmotic pressure difference between saltwater and freshwater is harnessed for energy, presents a sustainable and renewable energy source with significant potential. Furthermore, the field of medical research is looking at innovative drug delivery systems that utilize osmotic principles, offering precise and controlled administration of medications within the body. As technology and understanding in this field continue to evolve, the applications of osmosis are expected to expand, addressing various global challenges in water sustainability, energy generation, and healthcare.
See also
Brining
Homeostasis
Osmoregulation
Osmotic shock
Osmotic power
Plasmolysis
Reverse osmosis plant
Salinity gradient power
Water potential | biology | 1027557 | https://sv.wikipedia.org/wiki/Lotuseffekt | Lotuseffekt | Lotuseffekten kan sägas vara ett tings förmåga att hålla sig självt rent. Namnet kommer ursprungligen från Lotusblomman som har ett mycket ojämnt vaxskikt. Det har till följd att smuts endast har kontakt med en mycket liten del av blomman. När en vattendroppe rinner på blomman fastnar smutsen lättare på vattendroppen än på blomman som på så vis håller sig ren. På grund av enkelheten att tvätta saker som besitter lotuseffekten har denna överförts till bland annat målarfärg och billack.
Hemligheten bakom lotuseffekten är blommans superhydrofobiska yta. Det beror dels på att ytan är av vax, som i sig är vattenavstötande, men också på att vaxet är format på ett speciellt sätt med regelbundna ojämnheter vilket minimerar energin i de kemiska bindningarna mellan vattnet och ytan.
Historia
Den första teoretiska forskning om lotuseffekten rappoterades av R. E. Johnson och R. H. Dettre år 1964, och sedan avslöjade Wilhelm Barthlott år 1977 nanostrukturen av lotusblad. År 1998 utvecklade J. F. Brown den bioniska strukturen, och därefer uppstod massor fler forskning om lotuseffekten, allt från grundforskning, till tillämpning.
Mekanism
Lotuseffekten har sedan länge observerats inom olika kulturer, men det var inte förrän uppfinningen av svepelektronmikroskop (SEM) vars mekanism bakom den förklarades. Med hjälp av SEM gjordes tydliga observationer av lotusytan inom mikro- och nano-skalan, och vad som upptäcktes var att lotusytan är täckt av små papillos som är i sin tur täckt av tunna vaxartade kristaller. Denna ojämna yta i kombination med vaxartade material är i princip det som möjliggör lotuseffekten. År 2011, presenterade Ensikat, Ditsche-Kuru, Neinhuis och Barthlott en mer djupgående beskrivning av lotusens ytstruktur och dess superhydrofobicitet. Med deras SEM skanning av ett lotusblad, uppskattades papilosen att vara 5-10 μm hög, 10-15 μm från varandra och 2,5-5 μm i diameter. Denna ojämna yta minskar kontakten mellan ytan och vatten då vattnet strävar efter minimal ytenergi genom geometrisk configuration, i detta fall anta ett sfär, istället för interfacial interaktion genom att tränga in i luckorna mellan papilosen. För övrigt, minskar också den relativt smala diametern av papillos kontakt arean mellan ytan och vatten, och det gör även den varierande höjden av pappilosen då bara de högsta papillos interagerar med vattnet. Vaxartade kristaller som tät täcker papilosen bidrar dessutom också till den låga kontakt arean eftersom deras kemiska uppbyggnad innehåller opolära metylgrupper (CH3) vars avskräcker yt-vatten interaktioner på grund av vattnets polära egenskap. Denna minimala kontaktytan är huvudorsaken bakom den mycket låga vidhäftning av vatten, superhydrofobicitet härstammar således härifrån som är i sin tur grunden bakom lotuseffekten och dess självrenande egenskap.
Referenser
Externa länkar
Bioteknik | swedish | 0.80608 |
yeast_dissolve_in_sugar/Whatistheprocessofye.txt |
What is the process of yeast cells breaking down sugar?
Sort
Profile photo for Bryan Bates
Bryan Bates
Eating is the best medicine.Author has 80 answers and 26.1K answer views1y
Yeast metabolizes sugar and starches through a process we call fermentation, and releases carbon dioxide as a waste product. It’s really the CO2 release that bread bakers and beer brewers are after, as this is what makes dough rise and beer bubbly.
Yeast is able to “digest” sugars using enzymes it produces in the same way that we use enzymes to break the chemical bonds binding our food together. Here is the chemical reaction that yeast uses to break down sucrose (table sugar) with the addition of water:
468 views
Promoted by Roundhouse Provisions
Profile photo for Matt Jennings
Matt Jennings
Dramatization only - Roundhouse Provisions
·
7mo
How do I stay fit as I get older?
Just look at the legendary Chuck Norris’s advice since he is now a whopping 81 years old and yet has MORE energy than me. He found a key to healthy aging… and it was by doing the opposite of what most of people are told. Norris says he started learning about this revolutionary new method when he noticed most of the supplements he was taking did little or nothing to support his health. After extensive research, he discovered he could create dramatic changes to his health simply focusing on 3 things that sabotage our body as we age.
“This is the key to healthy aging,” says Norris. “I’m living pro
Related questions
How does yeast break down starch into glucose?
What is the effect of sugar on baker’s yeast?
Can dry yeast be activated without sugar?
What happens when you add yeast to a sugar solution?
What will happen when the yeast cell is added to a sugar solution?
Profile photo for Exploring Health Education
Exploring Health Education
Studied HDISM (California Canada) (Graduated 1997)Author has 1.6K answers and 503.5K answer views
·
1y
Yeast cells break down sugar through a process called fermentation. This process is used by yeast to generate energy and produce ethanol and carbon dioxide as byproducts.The process of fermentation starts with the uptake of glucose, which is a type of sugar, into the yeast cell. The glucose is then converted into pyruvate through a series of enzyme-catalyzed reactions known as glycolysis.Next, the pyruvate is converted into ethanol and carbon dioxide through the process of alcoholic fermentation. This process is catalyzed by the enzyme alcohol dehydrogenase and results in the generation of ene
Profile photo for Sugreev Verma
Sugreev Verma
MSc from Dr. Ram Manohar Lohia Avadh University (Graduated 2010)
·
4y
Originally Answered: What enzyme in yeast breaks down glucose?
Zymase catalyzes the breakdown of sugars in yeast. It is also called invertase. It comprises eight different subunits, which means it has a very complex structure.
Profile photo for Sonal U
Sonal U
PG in Microbiology in Education & Learning to Science, Studying (Graduated 2021)Author has 97 answers and 17.4K answer views
·
1y
In the fermentation process, specific organisms break down organic compounds (carbohydrates) in the absence of oxigen to release energy and produce carbon dioxide and alcohol.
Yeast carries out fermentation, breking down suger in the absence of oxigen to produce carbon dioxide and ethanol. Fermentation is the mode of respiration in yeasts.
Hence,the Suger solition is used in experiment involving yeast cell because yeasts utilizes suger to carry out respiration to release energy for their survival.
Sponsored by Online Shopping Tools
Don't Pay $179/Year for Amazon Prime - Use This Trick Instead.
This simple trick can save tons of money on Amazon, but most Prime members are ignoring it.
Related questions
How does yeast make sugar? Does sugar make yeast grow? How do they both affect each other?
How can I instantly lower my blood sugar?
Is it possible to carry out fermentation at home with sugar and yeast?
What happens if you put too much sugar in yeast?
What happens if you eat yeast and sugar?
Profile photo for William Halmeck
William Halmeck
M.A. in Biology, Western Connecticut State University (Graduated 2009)Author has 5.2K answers and 8.8M answer views
·
Updated 6y
Related
How does yeast make ATP by breaking down glucose?
Yeast are facultative aerobes. When there is enough available oxygen (O2), cellular respiration produces ATP in mitochondria through aerobic respiration. However, under anaerobic conditions, yeast drive glycolysis through alcohol fermentation producing ATP anaerobically.
Glucose is oxidized anaerobically by NAD+, and aerobically by oxygen (O2). The free energy released through the oxidation of glucose is used to drive both substrate-level, and oxidative phosphorylation to make ATP.
Profile photo for Aj. Raymond James Ritchie
Aj. Raymond James Ritchie
Author has 13.5K answers and 24.4M answer views
11mo
Related
How does yeast make ATP by breaking down glucose?
By glycolysis and/or gloycolysis + the Krebs cycle. The succinate dehydrognase step in the Krebs cycle by yeast produces ATP not GTP otherwise the same as in any elementary biochem textbook.
Sponsored by Smarter Choices
What are the best supplements to help with hair growth?
We ranked the most popular brands and discovered the top 5 hair growth supplements. See our rankings.
Profile photo for Claudia Caldwell
Claudia Caldwell
Author: GoodbyeCarbCravings Author has 88 answers and 68.8K answer views
·
1y
Related
What is the process of slow fermentation that allows yeast to break down complex carbohydrates?
Slow fermentation is a process that uses yeast to break down complex carbohydrates, such as starches, into simpler compounds like glucose.
This type of fermentation enables us to create a variety of delicious and nutritious foods, from bread and beer to cheese and sauerkraut.
Here's how the slow fermentation process works:
•Yeast feeds on carbohydrates, releasing carbon dioxide bubbles in the process - this is why dough rises when left for long enough!
•The yeast releases enzymes that convert calories from carbohydrates into energy for its own growth.
•As the temperature increases during the long r
Profile photo for George Perry
George Perry
Trained as a biologist over 40 years agoAuthor has 1.1K answers and 1M answer views
·
6y
Related
How does yeast make ATP by breaking down glucose?
Through glycolysis and respiration. ATP is substrate produced in the first and through a complex proton pump in the later.
Sponsored by Grammarly
Hit the mark with every message.
Predict how your reader will react, see how you sound, and get the response you want—with Grammarly.
Profile photo for Tayyeba Ranjha
Tayyeba Ranjha
M.s.c from University of Gujrat (Graduated 2018)Author has 148 answers and 17.8K answer views
·
1y
Related
How does the cell break down glucose and sucrose?
Glucose and sucrose are broken down through a process called cellular respiration. This process takes place in the cell's mitochondria and involves a series of metabolic reactions that convert glucose and sucrose into energy in the form of ATP (adenosine triphosphate).
The breakdown of glucose and sucrose begins with glycolysis, which is the process of breaking down glucose into pyruvate. In this process, glucose is converted into two molecules of pyruvate, which are then converted into acetyl-CoA.
Sucrose is a disaccharide composed of glucose and fructose. It needs to be broken down into its mo
Profile photo for Zara Rowlands
Zara Rowlands
Author has 737 answers and 96.3K answer views
1y
Related
How does the cell break down glucose and sucrose?
Cells do not break down sucrose as that is broken down into glucose and fructose in the digestive tract. Fructose is converted to glucose in the liver once both the glucose and fructose are absorbed. Glucose is what cells break down in one of two process - glycolysis which is the first step towards energy production from glucose, and the hexose monophosphate shunt which produces ribose - a crucial sugar for DNA and RNA production, and nucleotides which perform various other functions in the body like co-enzyme formation from vitamins like B1, B2 and B3.
Sponsored by CDW Corporation
What if one innovative tool could meet all work needs?
CDW can empower easy team connection and collaboration with an all-in-one Google Workspace Solution.
Profile photo for Scott Ellenwood
Scott Ellenwood
I've fed my family for over Forty years. I can "cook".Author has 955 answers and 878.5K answer views
·
1y
Related
What happens when you add yeast to a sugar solution?
Add sugar to some water.
Add yeast to the solution.
Yeast “wakes up” and starts eating the sugar.
Yeast eats even more, then has to pee. It pees out alcohol.
Yeast reproduces.
Yeast keeps eating, peeing, and reproducing.
Eventually, the concentration of pee (alcohol) is so stong it kills a lot of the yeast.
Yeast no longer eat, pee, or reproduce.
People drink the solution, enjoy it, filter it, distill it, and continue the process.
Profile photo for Rebecca
Rebecca
read over much books on Dental HygieneAuthor has 120 answers and 73.2K answer views
·
1y
Related
How much sugar does yeast consume?
Yeast is a type of fungus that is commonly used in baking and brewing. Yeast consumes sugar as its primary source of energy and carbon, which is necessary for growth and reproduction. The amount of sugar that yeast consumes can vary depending on the specific conditions of the environment in which it is growing.
When yeast is used in baking, it consumes the sugar in the dough to produce carbon dioxide gas. This gas causes the dough to rise, making it light and fluffy. The amount of sugar consumed by the yeast in this process will depend on the amount of sugar that is present in the dough. Genera
Sponsored by NativePath
Eat This Once A Day And See How Your Legs, Ankles and Feet Feel.
Is it really possible to eliminate swollen legs or inflamed joints without medications?
Profile photo for Tony
Tony
took several online and physical courses regarding biologyAuthor has 1.5K answers and 2M answer views
·
4y
Related
How does a cell process sugar?
Well, it’s a bit of a process.
Sugar you eat in your food doesn’t make it to your cells in one piece. Many foods contain complex sugar that is not useable by your cells. So, the more complex sugars are broken down by enzymes in your digestive system. After the whole digestive process is done, the sugar is absorbed as glucose, a simple sugar.
After the glucose is done in the digestive tract, it is absorbed into the bloodstream. From here, cells can intake the glucose. The cells may follow one of two pathways with it.
The first pathway is the one that powers your entire body every second: cell resp
Profile photo for Swamulu Maduru
Swamulu Maduru
Engineer, story writer, question clarification,Author has 802 answers and 266K answer views
·
9mo
Related
Does sugar have any effect on active dry yeast?
Yes, sugar can have an effect on active dry yeast when used in bread or other yeast-based recipes. Active dry yeast is a type of baker's yeast that is commonly used to leaven bread and other baked goods. It is composed of live yeast cells that remain dormant until activated by warm water.
When sugar is added to the dough, it can impact the fermentation process and the overall performance of the yeast in several ways:
Activation: Yeast needs warm water (around 100°F or 37°C) to be activated. However, adding sugar to the warm water can provide an additional food source for the yeast, which can hel
Profile photo for Yashika Seth
Yashika Seth
Food blogger
·
Updated 4y
Related
What is the process of making sugar?
Once the sugarcanes are harvested they are loaded into trucks and taken to the sugar processing factory. Firstly, the sugarcane is weighed using an electronic weighbridge and then prepared for milling. Secondly, the Sugarcane juice is then extracted by pressing the prepared cane with the help of machines. Then, the Extracted juice mixed with water is weighed and filtered by vacuum filters. The juice is processed and heated to crystallize resulting in sugar's pristine white color. Sometimes followed by centrifugation to remove any remaining juice or syrup.
Thus, the sugar is separated from molas
Profile photo for Joseph Cohn
Joseph Cohn
Cooking Coach at Cooklikejoe/cooklikejoe.com (2018–present)Author has 183 answers and 343.4K answer views
·
4y
Related
How does a packet of yeast interact with sugar?
A packet of yeast is a dried culture of living fungus. When hydrated, the dormant yeast require nutrition to multiply. Sugar, C6H12O6, is perfect yeast food. The yeast metabolize the sugar producing carbon dioxide CO2 and water H2O to capture the energy stored in the bonds holding the sugar together. The sugar is also anabolized - used for building- into the cellulose (C6H10O5)n that is the primary structural material of the reproducing yeast.
Profile photo for Ritwik Sunny
Ritwik Sunny
Former Customer Support Executive at Ashok LeylandAuthor has 31.6K answers and 6.9M answer views
·
1y
Related
How does the cell break down glucose and sucrose?
Glucose and other food molecules are broken down by controlled stepwise oxidation to provide chemical energy in the form of ATP and NADH
Profile photo for Dhruv Sareen
Dhruv Sareen
Scientist, Stem cell/neuroscientist,philomath, epistemophile
·
4y
Related
How does a cell process sugar?
Cells require constant supply of energy to keep them alive and for all their necessary biological functions such as for making new molecules like proteins. This energy is obtained from chemical bonds stored in molecules of food components such as as sugar. Sugars are important fuel molecules and typically oxidized in the cell to ultimately form carbon dioxide (CO2) and water (H2O).
In the first step of the process large sugar molecules (polysaccharides) are broken down into simple sub units of sugar such as glucose through digestion via enzymes, which then enter the cytoplasm of the cells.
In th
Profile photo for Wayne Bottlick
Wayne Bottlick
Type 1 diabetic May 1966; biochem student in college & sinceAuthor has 6K answers and 8.8M answer views
·
1y
Related
What is the importance of cells being able to break down glucose?
Q: “What is the importance of cells being able to break down glucose?”
Since the breakdown of glucose in the cell cytoplasm (glycolysis) is the first step in the process called cellular respiration, which is the basis of cellular life here on earth, it’s extremely important; without being able to break down a glucose molecule (into two pyruvate molecules), the cell could not complete or even begin the other three steps: pyruvate oxidation, citric acid (aka Krebs) cycle, and oxidative phosphorylation. Without which, the cell has NO energy - and dies.
Now, there are alternative fuels besides gluco
Profile photo for Anthony G. Gelbert
Anthony G. Gelbert
Former Air Taxi Pilot
·
7y
Related
Why does ethanol break down cell membranes?
Ethyl alcohol is a drying agent. The phospholipid double layer that composes part of all cell membranes exists in an aqueous environment. It cannot hold its shape in the presence of this drying agent because the water is depleted. The deformation causes the failure of active and passive transport through the cell membrane. Although the cell can take a certain amount of drying, enough ethyl alcohol will result in cell death.
Profile photo for Nana Stallings
Nana Stallings
Author has 20.5K answers and 81.1M answer views
2y
Related
If you mix yeast, sugar, and lukewarm, how will they behave?
They will bubble and after a day or two create alcohol, that’s what it’s supposed to do. If you let it sit for about 15 minutes to bubble away, You can add flour salt and a little butter to make bread with it. I bake all my own bread l, have for years. I make that mixture when I do bread. It’s called proofing and it’s how you make sure he yeast will work. Then I add the flour, butter, salt and oatmeal, different grains,!or whatever you like to make a favorite bread.
Profile photo for Wayne Henderson
Wayne Henderson
Author has 1.3K answers and 5.2M answer views
6y
Related
Why can't yeast break down lactose?
Yeast have not evolved to use lactose because it has not been critical to their long-term survival to do so. In terms of environmental availability, lactose is exceedingly rare. Yeast, on the other hand, are everywhere and have other things to do than be prepared for something that would be as rare as winning the lottery.
Related questions
How does yeast break down starch into glucose?
What is the effect of sugar on baker’s yeast?
Can dry yeast be activated without sugar?
What happens when you add yeast to a sugar solution?
What will happen when the yeast cell is added to a sugar solution?
How does yeast make sugar? Does sugar make yeast grow? How do they both affect each other?
How can I instantly lower my blood sugar?
Is it possible to carry out fermentation at home with sugar and yeast?
What happens if you put too much sugar in yeast?
What happens if you eat yeast and sugar?
Can too much sugar kill yeast?
What is the best "sugar" to proof yeast for bread?
What is the result of yeast, juice, and sugar being combined?
How do you activate yeast without sugar?
What happens if you don't add sugar to yeast?
Related questions
How does yeast break down starch into glucose?
What is the effect of sugar on baker’s yeast?
Can dry yeast be activated without sugar?
What happens when you add yeast to a sugar solution?
What will happen when the yeast cell is added to a sugar solution?
How does yeast make sugar? Does sugar make yeast grow? How do they both affect each other?
AD
AD
Advertisement
AboutCareersPrivacyTermsContactLanguagesYour Ad ChoicesPress© Quora, Inc. 2024 | biology | 585 | https://da.wikipedia.org/wiki/Sukrose | Sukrose | Sukrose eller sakkarose (også kaldet køkkensukker, raffineret hvidt sukker eller sukker uden fiber; kemisk formel: C12H22O11) er et kulhydrat. Det er et disakkarid sammensat af glukose og fruktose vha. en glykosidbinding og en fruktosidbinding.
Sukrose er 50 % glukose. Hvis kroppen ikke indtager tilstrækkelige mængder glucose, stivelse eller andre kulhydrater som ender i form af glukosemolekyler efter at være blevet fordøjet, så producerer kroppen selv den relativt begrænsede mængde som er nødvendig for at hjernen og nervesystemet kan fungere, og der suppleres med ketonstoffer fra nedbrydning af kroppens fedt.
De resterende 50 % af sukrosemolekylet er fruktose. Fruktose i større mængder, især i raffineret form som sukrose, er årsag til fedme og insulinresistens. Det sultregulerende hormon leptin registreres ikke af hjernen, da insulin blokerer for signalet - se fruktose. Fruktose er ikke essentielt for nogen kropsfunktion.
Ved hydrolyse kan sukrose adskilles i disse bestanddele, hvorved fremkommer en blanding kaldet invertsukker.
Fruktose findes i alle frugter, og når det optages i blodet bliver det gennem portåre ført til leveren, hvor det gennem isemorase enzymer bliver omstruktureret til glukose der indgår i glykolysen. Desuden reagerer beta-cellerne i bugspytkirtlerne, der producerer insulin ikke på andre stoffer end glukose og reagerer slet ikke på fruktose. Man har endnu ikke fuldstændig kortlagt årsagen til type 2 diabetes, men intet tyder på at det forårsaget af svingninger i blodsukker eller insulin i blodet.
Kulhydrater | danish | 0.676532 |
yeast_dissolve_in_sugar/PMC7466055.txt | Skip to main content
U.S. flagAn official website of the United States government Here's how you know
NIH NLM LogoLog in
Access keysNCBI HomepageMyNCBI HomepageMain ContentMain Navigation
Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now.
Search PMC Full-Text Archive
Search PMC Full-Text Archive
Search in PMC
Advanced Search User Guide
Journal List Microorganisms PMC7466055
As a library, NLM provides access to scientific literature. Inclusion in an NLM database does not imply endorsement of, or agreement with, the contents by NLM or the National Institutes of Health.
Learn more: PMC Disclaimer | PMC Copyright Notice
Logo of microorg
Microorganisms. 2020 Aug; 8(8): 1142.
Published online 2020 Jul 28. doi: 10.3390/microorganisms8081142
PMCID: PMC7466055
PMID: 32731589
The Role of Yeasts in Fermentation Processes
Sergi Maicas
Author information Article notes Copyright and License information PMC Disclaimer
Go to:
Abstract
In recent years, vessels have been discovered that contain the remains of wine with an age close to 7000 years. It is unclear whether, in ancient times, humans accidentally stumbled across fermented beverages like wine or beer, or was it a product intended as such. What is a fact is that since then, alcoholic beverages have been part of the diet and culture of many of the civilizations that have preceded us. The typical examples of beer and wine are an example of many other drinks resulting from the action of yeasts. In addition to these two beverages, various companies have developed other types of fermented foods and non-alcoholic beverages prepared in a traditional or commercial manner. The climatic conditions, the availability of raw material and the preferences of each region have conditioned and favored the maintenance of some of these products. In addition to the aforementioned traditional alcoholic beverages produced from fruits, berries, or grains, humans use yeast in the production of chemical precursors, global food processing such as coffee and chocolate, or even wastewater processing. Yeast fermentation is not only useful in food manufacturing. Its uses extend to other products of high interest such as the generation of fuel from vegetable sources.
Keywords: yeast, non-Saccharomyces yeast, wine, beer, beverages
Go to:
1. Introduction
Fermentation is a well-known natural process used by humanity for thousands of years with the fundamental purpose of making alcoholic beverages, as well as bread and by-products. Upon a strictly biochemical point of view, fermentation is a process of central metabolism in which an organism converts a carbohydrate, such as starch or sugar, into an alcohol or an acid. For example, yeast performs fermentation to obtain energy by converting sugar into alcohol. Fermentation processes were spontaneously carried out before the biochemical process was fully understood. In the 1850s and 1860s, the French chemist and microbiologist Louis Pasteur became the first scientist to study fermentation, when he demonstrated that this process was performed by living cells. Fermentation processes to produce wines, beers and ciders are traditionally carried out with Saccharomyces cerevisiae strains, the most common and commercially available yeast. They are well known for their fermentative behavior and technological characteristics which allow obtaining products of uniform and standard quality. Many other important industrial products are the result of fermentation, such as yogurt, cheese, bread, coffee. Yeasts also play a key role in wastewater treatment or biofuel production. Upon a biochemical point of view, fermentation is carried out by yeasts (and some bacteria) when pyruvate generated from glucose metabolism is broken into ethanol and carbon dioxide (Figure 1).
An external file that holds a picture, illustration, etc.
Object name is microorganisms-08-01142-g001.jpg
Figure 1
Central metabolism of fermentation in yeasts.
The schematic chemical equation for the production of ethanol from glucose is as follows:
C6H12O6(glucose)⟶2C2H5OH(ethanol)+CO2(carbon dioxide)
Under absence or oxygen-limited conditions, ethanol is produced from acetaldehyde, and two moles of ATP are generated. This is not a fully satisfactory reaction for cells, as they have to consume high amounts of glucose to deliver enough ATP to the system. As a consequence, ethanol is accumulated and when this occurs the fermentative activity is stopped [1].
1.1. Yeasts
Yeasts are eukaryotic microorganisms that live in a wide variety of ecological niches, mainly in water, soil, air and on plant and fruit surfaces. Perhaps the most interesting habitat at this point is the latter, since they directly intervene in the decomposition of ripe fruit and participate in the fermentation process. In this natural environment, yeasts can carry out their metabolism and fermentation activity satisfactorily as they have the necessary nutrients and substrates [2]. On a nutritional level, yeasts are not particularly demanding compared to other microorganisms such as lactic acid bacteria. However, their growth is supported by the existence of basic compounds such as fermentable sugars, amino acids, vitamins, minerals and also oxygen. Upon a morphological point of view, yeasts present a high morphological divergence, with round, ellipsoidal and oval shapes being the most common. In fact, in the identification processes, microscopic evaluation is the first resource followed by other more discriminatory tests such as microbiological and biochemical ones. In a next stage, the classical classification includes other more laborious tests such as those of sugar fermentation and amino acid assimilation [2]. The production and tolerance to ethanol, organic acids and SO2 are also important tools to differentiate among species. The reproduction of yeasts is mainly by budding, which results in a new and genetically identical cell. Budding is the most common type of asexual reproduction, although cell fission is a characteristic of yeasts belonging to the genus Schizosaccharomyces. Growing conditions that lead to nutrient starvation, such as lack of amino acids, induce sporulation, which is a mechanism used by yeasts to survive in adverse conditions. As a result of sporulation, yeast cells suffer from genetic variability. In industrial fermentation processes, the asexual reproduction of yeasts is advisable to ensure the preservation of the genotype and to maintain stable fermentation behaviour that does not derive from it for as long as possible. At the metabolic level, yeasts are characterised by their capacity to ferment a high spectrum of sugars, among which glucose, fructose, sucrose, maltose and maltotriose predominate, found both in ripe fruit and in processed cereals. In addition, yeasts tolerate acidic environments with pH values around 3.5 or even less. According to technological convenience, yeasts are divided into two large groups namely Saccharomyces and non-Saccharomyces. Morphologically, Saccharomyces yeasts can be round or ellipsoidal in shape depending on the growth phase and cultivation conditions. S. cerevisiae is the most studied species and the most utilized in the fermentation of wines and beers due to its satisfactory fermentative capacity, rapid growth and easy adaptation. They tolerate concentrations of SO2 that normally most non-Saccharomyces yeasts do not survive. However, despite these advantages, it is possible to find in the nature representatives of S. cerevisiae that do not necessarily have these characteristics.
1.2. Non-Saccharomyces Yeasts
Non-Saccharomyces yeasts are a group of microorganisms used in numerous fermentation processes, since their high metabolic differences allow the synthesis of different final products. Generally, many of these yeasts capable of modifying the sensory quality of wines are considered as contaminants, so eliminating them or keeping them at low levels was a basic objective in the past [3]. In order to eliminate their activity in wine fermentation, it is usual to disinfect the tanks and fermentation containers using sulfite. This perception has been modified year after year, gaining relevance the action of these yeasts in the spontaneous fermentation, since they contribute positively in the final sensory quality of the wine. These yeasts are the majority in the initial phase of spontaneous fermentation to the point where the concentration of ethanol reaches 4 and 5% v/v. At that point, between alcohol and the exhaustion of dissolved oxygen, their growth is inhibited [4]. When the process is completed, Saccharomyces yeasts, the most resistant to ethanol, predominate and complete the fermentation. It has been reported that some non-Saccharomyces yeasts are able to survive toward the end of the spontaneous fermentation and exert their metabolic activity, thus contributing positively to the sensory quality of wines. Based on this evidence, in recent years, many researchers have focused their studies in understanding the nature and fermentative activity of the non-Saccharomyces yeasts [5]. The findings demonstrated the enormous potential of these yeasts for use in the fermentation of traditional and nontraditional beverages. Despite the fact that most non-Saccharomyces yeasts show some technological disadvantages compared to S. cerevisiae such as lower fermentative power and production of ethanol, non-Saccharomyces yeasts possess characteristics that in S. cerevisiae are absent, for instance, production of high levels of aromatic compounds such as esters, higher alcohols and fatty acids [6]. In addition, it has been reported that the fermentative activity of these yeasts is manifested in the presence of small amounts of oxygen which leads to an increase in cell biomass and the decrease in ethanol yield, a strategy that can be used to reduce the ethanol content of wines produced in coculture with S. cerevisiae [7]. With the aim of exploiting the positive characteristics of non-Saccharomyces yeasts and reducing their negative impact, fermentations with mixed and sequential cultures with S. cerevisiae can be performed to produce fermented beverages with different sensory profiles [8]. The most important fact is related to the potential for producing a broad variety of compounds of sensory importance necessary to improve the organoleptic quality of wines and beers. The findings reported so far in literature have led to rethink the role of these yeasts in fermentative processes and to evaluate their use in the development of new products. Among the most studied non-Saccharomyces yeasts that reached special importance for researchers include Candida, Kloeckera, Hanseniaspora, Brettanomyces, Pichia, Lanchacea and Kluyveromyces, among others.
Go to:
2. Yeast Fermentation Processes
2.1. Alcoholic Fermentations
The production of alcoholic beverages from fermentable carbon sources by yeast is the oldest and most economically important of all biotechnologies. Yeast plays a vital role in the production of all alcoholic beverages. Yeast plays a vital role in the production of all alcoholic beverages and the selection of suitable yeast strains is essential not only to maximise alcohol yield, but also to maintain beverage sensory quality [2].
2.1.1. Wine Fermentation In wine fermentation, strains with specific characteristics are needed, for instance, highly producers of ethanol to reach values of 11–13% v/v, typically found in this beverage. On the other hand, beers and ciders contain less amounts of ethanol with a balanced and distinctive sensory profile characteristic of each one. In recent years, new consuming trends and requirements for new and innovative products have emerged. This situation led to rethink about the existing fermented beverages and to meet the demands of consumers. Yeasts are largely responsible for the complexity and sensory quality of fermented beverages. Based on this, current studies are mainly focused on the search of new type of yeasts with technological application. Non-Saccharomyces yeasts have always been considered contaminants in the manufacture of wine and beer. Therefore, procedures for eliminating them are routinely utilized such as must pasteurization, addition of sulfite and sanitization of equipment and processing halls. In recent years, the negative perception about non-Saccharomyces yeasts has been changing due to the fact that several studies have shown that during spontaneous fermentations of wine, these yeasts play an important role in the definition of the sensory quality of the final product. Based on this evidence, the fermentative behavior of some non-Saccharomyces yeasts is being studied in deep with the purpose of finding the most adequate conditions and the most suitable strain to be utilized in the production of fermented beverages.
2.1.2. Beer Fermentation Beer is the most consumed alcoholic beverage worldwide. It is traditionally made from four key ingredients: malted cereals (barley or other), water, hops, and yeast. Each of these ingredients contributes to the final taste and aroma of beer. During fermentation, yeast cells convert cereal-derived sugars into ethanol and CO2. At the same time, hundreds of secondary metabolites that influence the aroma and taste of beer are produced. Variation in these metabolites across different yeast strains is what allows yeast to so uniquely influence beer flavor [9]. Although most breweries use pure yeast cultures for fermentation, spontaneous or mixed fermentation is nowadays used for some specialty beers. These fermentation procedures involve a mix of different yeast species (and bacteria as well) that contribute to the final product sequentially, giving the beer a high degree of complexity. Commonly, breweries have their own stock of selected yeasts for their specific beers. As it is well-known, two types of yeast are used in brewing: S. cerevisiae as the top-fermenting yeast to make ales while S. pastorianus is a bottom-fermenting yeast used in lager brewing processes [10].
2.1.3. Cider Fermentation Cider is another alcoholic beverage derived from the apple fruit industry, very popular in different countries in the world, mainly Europe, North America, and Australia [11]. Although traditional ciders are produced from spontaneous fermentation of juice carried out by autochthonous yeasts, selected S. cerevisiae strains are also commonly used to carry out alcoholic fermentation. This ensures a consistent quality of the finished products [12]. Some other non-Saccharomyces yeast species are involved in spontaneous fermentation of apple juice for cider production. However, these yeasts contribute at a lesser extent than Saccharomyces and can be producers of off-flavours [13]. Research articles on this type of product are scarce compared to wine, especially in phenomena associated with microbial activities. The microbiome of wine fermentation and its dynamics, the organoleptic improvement of healthy and pleasant products and the development of starters are now extensively studied. Although the two beverages seem close in terms of microbiome and process (with both alcoholic and malolactic fermentations), the inherent properties of the raw materials and different production and environmental parameters make it worthwhile research on the specificities of apple fermentation. An excellent review of the microbial implications associated with cider production, from ecosystem considerations to associated activities and the influence of process parameters [11].
In addition to these three worldwide-famous fermented beverages, there are many others made from fruit in various countries in Africa, Asia, and Latin America. Although its consumption is local or regional, in some countries drinks made using fruits such as bananas or grapes as raw materials are very popular. The most widespread alcoholic fruit drink in Eastern Africa is banana beer, which in addition to gastronomic interest is especially culturally relevant. Banana beer is a mixed beverage made from bananas and a cereal flour (often sorghum flour) [14]. Dates in North Africa, pineapples and cashew fruits in Latin America and jack fruits in Asia are other of the most relevant products.
2.2. Non-Alcoholic Fermentations
Moreover, yeast can act in the fermentation of global non-alcoholic products (bread, chocolate or coffee, beverages such as kefir, sodas, lemonades, and vinegar or even biofuels and other chemicals.
2.2.1. Bread Fermentation The fermentation of the dough made by the yeasts is the most critical phase in the making of bread. The fermentative yield of yeast cells during this fermentation is crucial and determines the final quality of the bread. Yeasts not only produce CO2 and other metabolites that influence the final appearance of the dough, volume, and texture, and of course, the taste of the bread. The yeast strain, pregrowth conditions, its activity during the dough fermentation process, the fermentation conditions, as well as the dough ingredients are basic to control the process. The fermentation rate is also conditioned by the ingredients of the dough, including the amounts of sugar and salt used in its preparation. Commercial bread producers currently produce various types of dough such as lean, sweet or frozen dough. Depending on the type of dough, and to obtain optimal fermentation rates, it is recommended to use suitable yeast strains with specific phenotypic traits [15].
2.2.2. Coffee Fermentation Yeasts play an important role in coffee production, in the post-harvest phase. Its performance can be done in two phases. On the one hand, aerobically, in which the berries just collected are deposited in a tank and the yeasts are allowed to act. This process is carried out under control of basic parameters, such as time and temperature. Alternatively, coffee berries are deposited in a container mixed with water and microorganisms are allowed to act anaerobically (in the absence of oxygen). This second process is more homogeneous and easy to control than the aerobic. Sometimes, coffee beans are even fermented in a mixed process, first in an aerobic and finally anaerobic manner [16]. To develop these processes in a satisfactory manner, and to preserve/improve the organoleptic properties of coffee, refine its sweetness, control acidity, give them body or add sensory notes (chocolate, caramel, fruits) mucilage should be removed. The process is naturally carried out by the yeasts present in the mixture, although the process can be improved by the addition of appropriate enzymes (polygalacturonase, pectin lyase, pectin methylesterase) [17].
2.2.3. Chocolate Fermentation Raw cacao beans have a bitter and astringent taste, because of high phenolic content. Anthocyanins are one group of these polyphenols, and it both contributes to astringency and provide the reddish-purple color. Fermentation allows the enzymatic breakdown of proteins and carbohydrates inside the bean, creating flavor development. This is aided by microbial fermentation, which create the perfect environment through the fermentation of the cacao pulp surrounding the beans. This processing step enables the extraction of flavor from cacao and contributes to the final acidity of the final product. Yeasts (and also bacteria) ferment the juicy pulp among the cacao beans by different methods, generally following a an anaerobic phase and an aerobic phase. During the anaerobic phase, the sugars of the pulp (sucrose, glucose, fructose) are consumed by yeasts using anaerobic respiration to yield carbon dioxide, ethanol, and low amounts of energy [18,19]. The aerobic stage is dominated by lactic and acetic-acid-producing bacteria [20].
2.3. Not Only Food: Biofuels and Other Chemicals
The fermentation processes of substrates such as xylose are also of high interest on an industrial level. In addition to expanding the range of substrates that can be used for this purpose, they allow the environmental cost of efficient production of biofuels and other advanced chemicals to be reduced. Some interesting approaches have been made in biorefinery to reprogram yeast for use in these bioprocesses [21,22,23].
Go to:
3. Special Issue on “Yeast Fermentation”
This issue in Microorganisms aims to contribute to the update of knowledge regarding yeasts, regarding both basic and also applied aspects. Among the great contributions to this issue we have a manuscript devoted to the brewing industry and the recent isolation of the yeast Saccharomyces eubayanus [24]. The use of headspace solid-phase microextraction followed by gas chromatography-mass spectrometry (HS-SPME-GC-MS) has contributed to the production of volatile compounds in wild strains and to compare them to a commercial yeast. All these findings highlight the potentiality of this yeast to produce new varieties of beers. Haile et al. [17] have explored the possibility to identify and select pectinolytic yeasts that have potential use as a starter culture for coffee fermentation. Almost 30 isolates, eight of them with the ability to produce pectinase enzymes were identified and confirmed by using molecular biology techniques. A helpful bioinformatics tool (MEGA 6) was also used to generate phylogenetic trees able to determine the evolutionary relationship of yeasts obtained from their experiments. Biofuel production by recombinant Saccharomyces cerevisiae strains with essential genes and metabolic networks for xylose metabolism has been also reported [23]. The authors have shown that the deletion of cAMP phosphodiesterase genes PDE1 and PDE2 can increase xylose utilization. Moreover, the door is opened to provide new targets for engineering other xylose-fermenting strains. The utilization of xylose, the second most abundant sugar component in the hydrolysates of lignocellulosic materials, is a relevant issue. Understanding the relationship between xylose and the metabolic regulatory systems in yeasts is a crucial aspects where hexokinase 2 (Hxk2p) is involved [25]. All of these processes can be damaged if contaminated. Because most fermentation substrates are not sterile, contamination is always a factor to consider. With a very interesting approach, a genetically modified strain of Komagataella phaffii yeast was used for the use of glycerol as a base substance in lactate production. Polyactide, a bioplastic widely used in the pharmaceutical, automotive, packaging and food industries was produced. The disruption of the gene encoding arabitol dehydrogenase (ArDH) was achieved, which improves the production of lactic acid by K. phaffii as a biocatalyst [26]. Seo et al. [27] have developed and proposed alternative solutions to control contamination. This review includes information on industrial uses of yeast fermentation, microbial contamination and its effects on yeast fermentations. Finally, they describe strategies for controlling microbial contamination.
Go to:
Acknowledgments
Thanks to all the authors and reviewers for their excellent contributions to this Special Issue. Additional thanks to the Microorganisms Editorial Office for their professional assistance and continuous support.
Go to:
Conflicts of Interest
The editors declares no conflict of interest.
Go to:
References
1. Puligundla P., Smogrovicova D., Obulam V.S.R., Ko S. Very high gravity (VHG) ethanolic brewing and fermentation: A research update. J. Ind. Microbiol. Biotechnol. 2011;38:1133–1144. doi: 10.1007/s10295-011-0999-3. [PubMed] [CrossRef] [Google Scholar]
2. Walker G.M., Stewart G.G. Saccharomyces cerevisiae in the Production of Fermented Beverages. Beverages. 2016;2:30. doi: 10.3390/beverages2040030. [CrossRef] [Google Scholar]
3. Ciani M., Maccarelli F. Oenological properties of non-Saccharomyces yeasts associated with wine-making. World J. Microbiol. Biotechnol. 1997;14:199–203. doi: 10.1023/A:1008825928354. [CrossRef] [Google Scholar]
4. Grangeteau C., Gerhards D., Terrat S., Dequiedt S., Alexandre H., Guilloux-Benatier M., von Wallbrunn C., Rousseaux S. FT-IR spectroscopy: A powerful tool for studying the inter- and intraspecific biodiversity of cultivable non-Saccharomyces yeasts isolated from grape must. J. Microbiol. Methods. 2016;121:50–58. doi: 10.1016/j.mimet.2015.12.009. [PubMed] [CrossRef] [Google Scholar]
5. Estela-Escalante W., Moscosa-Santillán M., González-RamÃrez J., Rosales-Mendoza S. Evaluation of the potential production of ethanol by Candida zemplinina yeast with regard to beer fermentation. J. Am. Soc. Brew. Chem. 2017;75:130–135. doi: 10.1094/ASBCJ-2017-2532-01. [CrossRef] [Google Scholar]
6. Cordero-Bueso G., Esteve-Zarzoso B., Cabellos J., Gil-DÃaz M., Arroyo T. Biotechnological potential of non-Saccharomyces yeasts isolated during spontaneous fermentations of Malvar (Vitis vinifera cv. L.) Eur. Food Res. Technol. 2013;236:193–207. doi: 10.1007/s00217-012-1874-9. [CrossRef] [Google Scholar]
7. Ciani M., Capece A., Comitini F., Canonico L., Siesto G., Romano P. Yeast interactions in inoculated wine fermentation. Front. Microbiol. 2016;7 doi: 10.3389/fmicb.2016.00555. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
8. Canonico L., Agarbati A., Comitini F., Ciani M. Torulaspora delbrueckii in the brewing process: A new approach to enhance bioflavour and to reduce ethanol content. Food Microbiol. 2016;56:45–51. doi: 10.1016/j.fm.2015.12.005. [PubMed] [CrossRef] [Google Scholar]
9. Dzialo M.C., Park R., Steensels J., Lievens B., Verstrepen K.J. Physiology, ecology and industrial applications of aroma formation in yeast. FEMS Microbiol. Rev. 2017;41:S95–S128. doi: 10.1093/femsre/fux031. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
10. Libkind D., Hittinger C.T., Valério E., Gonçalves C., Dover J., Johnston M., Gonçalves P., Sampaio J.P. Microbe domestication and the identification of the wild genetic stock of lager-brewing yeast. Proc. Natl. Acad. Sci. USA. 2011;108:14539–14544. doi: 10.1073/pnas.1105430108. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
11. Cousin F.J., Le Guellec R., Schlusselhuber M., Dalmasso M., Laplace J.M., Cretenet M. Microorganisms in fermented apple beverages: Current knowledge and future directions. Microorganisms. 2017;5:39. doi: 10.3390/microorganisms5030039. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
12. Lorenzini M., Simonato B., Slaghenaufi D., Ugliano M., Zapparoli G. Assessment of yeasts for apple juice fermentation and production of cider volatile compounds. LWT. 2019;99:224–230. doi: 10.1016/j.lwt.2018.09.075. [CrossRef] [Google Scholar]
13. Pando Bedriñana R., Querol Simón A., Suárez Valles B. Genetic and phenotypic diversity of autochthonous cider yeasts in a cellar from Asturias. Food Microbiol. 2010;27:503–508. doi: 10.1016/j.fm.2009.11.018. [PubMed] [CrossRef] [Google Scholar]
14. Gensi R., Kyamuhangire W., Carasco J. Traditional production method and storage characteristics for banana beer (tonto) in Uganda. Acta Hortic. 2000;540:569–574. doi: 10.17660/ActaHortic.2000.540.62. [CrossRef] [Google Scholar]
15. Struyf N., Van der Maelen E., Hemdane S., Verspreet J., Verstrepen K., Courtin C. Bread Dough and Baker’s Yeast: An Uplifting Synergy. Compr. Rev. Food Sci. Food Saf. 2017;16:850–867. doi: 10.1111/1541-4337.12282. [PubMed] [CrossRef] [Google Scholar]
16. de Melo Pereira G., Soccol V., Pandey A., Medeiros A., Andrade Lara J., Gollo A., Soccol C. Isolation, selection and evaluation of yeasts for use in fermentation of coffee beans by the wet process. Int. J. Food Microbiol. 2014;188:60–66. doi: 10.1016/j.ijfoodmicro.2014.07.008. [PubMed] [CrossRef] [Google Scholar]
17. Haile M., Kang W.H. Isolation, Identification, and Characterization of Pectinolytic Yeasts for Starter Culture in Coffee Fermentation. Microorganisms. 2019;7:401. doi: 10.3390/microorganisms7100401. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
18. Ho V., Zhao J., Fleet G. Yeasts are essential for cocoa bean fermentation. Int. J. Food Microbiol. 2014;174:72–87. doi: 10.1016/j.ijfoodmicro.2013.12.014. [PubMed] [CrossRef] [Google Scholar]
19. Papalexandratou Z., Nielsen D. It’s gettin’ hot in here: Breeding robust yeast starter cultures for cocoa fermentation. Trends Microbiol. 2016;24:168–170. doi: 10.1016/j.tim.2016.01.003. [PubMed] [CrossRef] [Google Scholar]
20. Ho V., Fleet G., Zhao J. Unravelling the contribution of lactic acid bacteria and acetic acid bacteria to cocoa fermentation using inoculated organisms. Int. J. Food Microbiol. 2018;279:43–56. doi: 10.1016/j.ijfoodmicro.2018.04.040. [PubMed] [CrossRef] [Google Scholar]
21. Kwak S., Jo J.H., Yun E.J., Jin Y.S., Seo J.H. Production of biofuels and chemicals from xylose using native and engineered yeast strains. Biotechnol. Adv. 2019;37:271–283. doi: 10.1016/j.biotechadv.2018.12.003. [PubMed] [CrossRef] [Google Scholar]
22. Jansen M., Bracher J., Papapetridis I., Verhoeven M., de Bruijn H., de Waal P., van Maris A., Klaassen P., Pronk J. Saccharomyces cerevisiae strains for second-generation ethanol production: From academic exploration to industrial implementation. FEMS Yeast Res. 2017;17 doi: 10.1093/femsyr/fox044. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
23. Wu M., Li H., Wei S., Wu H., Wu X., Bao X., Hou J., Liu W., Shen Y. Simulating Extracellular Glucose Signals Enhances Xylose Metabolism in Recombinant Saccharomyces cerevisiae. Microorganisms. 2020;8:100. doi: 10.3390/microorganisms8010100. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
24. Urbina K., Villarreal P., Nespolo R.F., Salazar R., Santander R., Cubillos F.A. Volatile Compound Screening Using HS-SPME-GC/MS on Saccharomyces eubayanus Strains under Low-Temperature Pilsner Wort Fermentation. Microorganisms. 2020;8:755. doi: 10.3390/microorganisms8050755. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
25. Zheng L., Wei S., Wu M., Zhu X., Bao X., Hou J., Liu W., Shen Y. Improving Xylose Fermentation in Saccharomyces cerevisiae by Expressing Nuclear-Localized Hexokinase 2. Microorganisms. 2020;8:856. doi: 10.3390/microorganisms8060856. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
26. Tamires Moreira Melo N., Pontes G.C., Procópio D.P., Cunha G., Eliodório K.P., Paes H.C., Basso T.O., Parachin N.S. Evaluation of Product Distribution in Chemostat and Batch Fermentation in Lactic Acid-Producing Komagataella phaffii Strains Utilizing Glycerol as Substrate. Microorganisms. 2020;8:781. doi: 10.3390/microorganisms8050781. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
27. Seo S.O., Park S.K., Jung S.C., Ryu C.M., Kim J.S. Anti-Contamination Strategies for Yeast Fermentations. Microorganisms. 2020;8:274. doi: 10.3390/microorganisms8020274. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
Articles from Microorganisms are provided here courtesy of Multidisciplinary Digital Publishing Institute (MDPI)
OTHER FORMATS
PDF (325K)
ACTIONS
Cite
Collections
SHARE
RESOURCES
Similar articles
Cited by other articles
Links to NCBI Databases
FOLLOW NCBI
Connect with NLM
National Library of Medicine
8600 Rockville Pike
Bethesda, MD 20894
Web Policies
FOIA
HHS Vulnerability Disclosure
Help
Accessibility
Careers
NLM
NIH
HHS
USA.gov
Tell us what you think!Close
| biology | 71292 | https://da.wikipedia.org/wiki/Kefir | Kefir | Kefir er produktet af en gæringsproces foretaget af en koloni af symbiotiske bakterie- og gærarter i mælk. Kolonien er et eksempel på en såkaldt SCOBY (Symbiotic Colony Of Bacteria and Yeast). Mælkekefiren stammer fra Kaukasus, og har – mere eller mindre videnskabeligt – været koblet sammen med folks lange levealder. Kolonien består af en matrix af polysaccharider udskilt af visse bakterier, hvori hele kolonien lever. Produktion af kefir består normalt af en gæringsproces ved stuetemperatur i mælk i et døgns tid. Væskefasen (kefiren) sis fra og kefirgrynene tilsættes ny mælk. Kefir opbruger laktose og andre sukkerarter, hvorfor den også tåles af laktose-lavtolerante, og den producerer blandt andet mælkesyre, ethanol og korte fedtsyrer. Kefir har konsistens som drikkeyoghurt, en syrlig smag og en lav alkoholprocent.
Der findes også vandkefir, en kefir-type, der vokser i vand frem for mælk.
Referencer
Eksterne henvisninger
Syrnede mejeriprodukter
Kaukasus | danish | 0.777337 |
humans_closest_relatives_after_primates/Treeshrew.txt |
The treeshrews (also called tree shrews or banxrings) are small mammals native to the tropical forests of South and Southeast Asia. They make up the entire order Scandentia, which split into two families: the Tupaiidae (19 species, "ordinary" treeshrews), and the Ptilocercidae (one species, the pen-tailed treeshrew).
Though called 'treeshrews', and despite having previously been classified in Insectivora, they are not true shrews, and not all species live in trees. They are omnivores; among other things, treeshrews eat fruit.
Treeshrews have a higher brain to body mass ratio than any other mammal, including humans, but high ratios are not uncommon for animals weighing less than 1 kg (2 lb).
Among orders of mammals, treeshrews are closely related to primates, and have been used as an alternative to primates in experimental studies of myopia, psychosocial stress, and hepatitis.
Name[edit]
The name Tupaia is derived from tupai, the Malay word for squirrel, and was provided by Sir Stamford Raffles.
Description[edit]
Dentition of Tupaia
Madras treeshrew (Anathana ellioti)
Northern smooth-tailed treeshrew (Dendrogale murina)
Northern treeshrew (Tupaia belangeri)
Common treeshrew (T. glis)
Horsfield's treeshrew (T. javanica)
Pygmy treeshrew (T. minor)
Pen-tailed treeshrew (1850 depiction of Ptilocercus lowii)
Treeshrews are slender animals with long tails and soft, greyish to reddish-brown fur. The terrestrial species tend to be larger than the arboreal forms, and to have larger claws, which they use for digging up insect prey. They have poorly developed canine teeth and unspecialised molars, with an overall dental formula of 2.1.3.33.1.3.3
Treeshrews have good vision, which is binocular in the case of the more arboreal species.
Reproduction[edit]
Female treeshrews have a gestation period of 45–50 days and give birth to up to three young in nests lined with dry leaves inside tree hollows. The young are born blind and hairless, but are able to leave the nest after about a month. During this period, the mother provides relatively little maternal care, visiting her young only for a few minutes every other day to suckle them.
Treeshrews reach sexual maturity after around four months, and breed for much of the year, with no clear breeding season in most species.
Behavior[edit]
Treeshrews live in small family groups, which defend their territory from intruders. Most are diurnal, although the pen-tailed treeshrew is nocturnal.
They mark their territories using various scent glands or urine, depending on the particular species.
Diet[edit]
Treeshrews are omnivorous, feeding on insects, small vertebrates, fruit, and seeds. Among other things, treeshrews eat Rafflesia fruit.
The pen-tailed treeshrew in Malaysia is able to consume large amounts of naturally fermented nectar from flower buds of the bertam palm Eugeissona tristis (with up to 3.8% alcohol content) the entire year without it having any effects on behaviour.
Treeshrews have also been observed intentionally eating foods high in capsaicin, a behavior unique among mammals other than humans. A single TRPV1 mutation reduces their pain response to capsaicinoids, which scientists believe is an evolutionary adaptation to be able to consume spicy foods in their natural habitats.
Taxonomy[edit]
They make up the entire order Scandentia, split into the families Tupaiidae, the treeshrews, and Ptilocercidae, the pen-tailed treeshrew. The 20 species are placed in five genera.
Treeshrews were moved from the order Insectivora into the order Primates because of certain internal similarities to primates (for example, similarities in the brain anatomy, highlighted by Sir Wilfrid Le Gros Clark), and classified as a "primitive prosimian", however they were soon split from the primates and moved into their own clade. Taxonomists continue to refine the treeshrews' relations to primates and to other closely related clades.
Molecular phylogenetic studies have suggested that the treeshrews should be given the same rank (order) as the primates and, with the primates and the flying lemurs (colugos), belong to the grandorder Euarchonta. According to this classification, the Euarchonta are sister to the Glires (lagomorphs and rodents), and the two groups are combined into the superorder Euarchontoglires. However, the alternative placement of treeshrews as sister to both Glires and Primatomorpha cannot be ruled out. Some studies place Scandentia as sister of the Glires, which would invalidate Euarchonta: It is this organization that is shown in the tree diagram below.
Euarchontoglires
Scandentia (treeshrews)
Glires
Lagomorpha (rabbits, hares, pikas)
Rodentia (rodents)
Primatomorpha
Dermoptera (Colugos)
†Plesiadapiformes
Primates
Several other arrangements of these orders have been proposed in the past, and the above tree is only a well-favored proposal. Although it is known that Scandentia is one of the most basal Euarchontoglire clades, the exact phylogenetic position is not yet considered resolved: It may be a sister of Glires, Primatomorpha, or Dermoptera, or separate from and sister to all other Euarchontoglires. Shared short interspersed nuclear elements (SINEs) offer strong evidence for scandentia belonging to the euarchonta group:
Euarchontoglires
Glires
Lagomorpha (rabbits, hares, pikas)
Rodentia (rodents)
Euarchonta
Scandentia (treeshrews)
Primatomorpha
Dermoptera (colugos)
Primates (†Plesiadapiformes, Strepsirrhini, Haplorrhini)
Order Scandentia[edit]
Main article: List of scandentians
The 23 species are placed in four genera, which are divided into two families. The majority are in the "ordinary" treeshrew family, Tupaiidae, but one species, the pen-tailed treeshrew, is different enough to warrant placement in its own family, Ptilocercidae; the two families are thought to have separated 60 million years ago. The former Tupaiidae genus Urogale was disbanded in 2011 when the Mindanao treeshrew was moved to Tupaia based on a molecular phylogeny.
Family Tupaiidae
Genus Anathana
Madras treeshrew, A. ellioti
Genus Dendrogale
Bornean smooth-tailed treeshrew, D. melanura
Northern smooth-tailed treeshrew, D. murina
Genus Tupaia
Northern treeshrew, T. belangeri
Golden-bellied treeshrew, T. chrysogaster
Bangka Island treeshrew, T. discolor
Striped treeshrew, T. dorsalis
Mindanao treeshrew, T. everetti
Sumatran treeshrew, T. ferruginea
Common treeshrew, T. glis
Slender treeshrew, T. gracilis
Javan treeshrew, T. hypochrysa
Horsfield's treeshrew, T. javanica
Long-footed treeshrew, T. longipes
Pygmy treeshrew, T. minor
Mountain treeshrew, T. montana
Nicobar treeshrew, T. nicobarica
Palawan treeshrew, T. palawanensis
Painted treeshrew, T. picta
Kalimantan treeshrew, T. salatana
Ruddy treeshrew, T. splendidula
Large treeshrew, T. tana
Family Ptilocercidae
Genus Ptilocercus
Pen-tailed treeshrew, P. lowii
Fossil record[edit]
The fossil record of treeshrews is poor. The oldest putative treeshrew, Eodendrogale parva, is from the Middle Eocene of Henan, China, but the identity of this animal is uncertain. Other fossils have come from the Miocene of Thailand, Pakistan, India, and Yunnan, China, as well as the Pliocene of India. Most belong to the family Tupaiidae; one fossil species described from the Oligocene of Yunnan is thought to be closer to the pen-tailed treeshrew.
Named fossil species include Prodendrogale yunnanica, Prodendrogale engesseri, and Tupaia storchi from Yunnan, Tupaia miocenica from Thailand, Palaeotupaia sivalicus from India and Ptilocercus kylin from Yunnan. | biology | 516558 | https://no.wikipedia.org/wiki/Urtre | Urtre | Urtre (Metasequoia glyptostroboides) er et sjeldent bartre, som tilhører sypressfamilien. Det vokser vilt bare noen få steder i midtre deler av Kina. Slekten Metasequoia ble beskrevet fra fossiler i 1941, men fire år senere ble den nålevende arten kjent for vitenskapen.
Beskrivelse
Det blir opp til 50 meter høyt. Kronen er kjegleformet på unge trær, men blir bred og rund på eldre trær. Unge greiner vokser oppover, men de eldre greinene henger stadig mere, og vokser enten horisontalt eller nedover. Barken er rødbrun og trevlete.
Urtreets blader er spesielle; de myke, lange nålene sitter motsatt i to rekker på grønne skudd, som igjen sitter parvis motsatt på rødbrune skudd. Slik ser bladene mer ut som parflikede løvtreblad enn typiske barnåler. Om høsten skifter bladene og de grønne skuddene farge til rødt og oransje, og felles samlet.
Hannblomstene har rakleform, og hunnblomstene er små og kongleaktige og sitter i grupper ytterst på greinene. Når konglene modnes, blir de 2-3 cm lange, brune og går fra å peke oppover til å henge ned.
Økologi og utbredelse
Urtreet vokste langs elver i dalbunnene i lignende habitater som sumpsypress (Taxodium distichum), men disse områdene er i de siste århundrene gjort om til rismarker. Noen trær vokser på mindre gunstige steder i fuktige raviner i dalsidene. Urtreet dannet ikke rene bestander, og vokste sannsynligvis sammen med løvtrær som lønn, kastanje, poppel, eik, vingenøtt, ambratre og Nyssa. Jorda er leire eller sand som er dannet ved nedbryting av sandstein, og den er svakt sur eller nøytral. Grunnvannsspeilet skifter med årstidene, men ligger aldri dypt. Klimaet kjennetegnes av varme somre og kalde vintre.
Arten er utbredt i midtre deler av Kina: Shizhu i Chongqing, Lichuan og Zhonglu i Hubei, og Longshan og Sangzhi i Hunan. De gjenstående trærne står i kanten av rismarker, og det er vanskelig å skille mellom naturlige og plantede trær. De eldste trærne er rester av den opprinnelige skogen. I 2006 ble det forsøkt å telle alle naturlige, store trær. Flest trær, 5360, ble funnet i Lichuan; i Longshan fant man bare fem trær og i Shizhu 28.
Den største trusselen mot urtreet er befolkningsvekst og habitatødeleggelse. Treet ble tidligere brukt til bygningstømmer og ved, og under Det store spranget på 1950-tallet ble mange trær hugget for å smelte jern. Det er nå forbudt å hugge naturlig voksende trær. Bestandene er sterkt fragmentert, og det er få muligheter for naturlig tilvekst. I IUCNs rødliste er urtre vurdert som sterkt truet.
Oppdagelse og systematikk
Den japanske paleobotanikeren S. Miki beskrev i 1941 slekten Metasequoia basert på fossiler fra tidlig pliocen funnet på den japanske øya Honshu. Han plasserte også fossiler fra Mandsjuria, Sakhalin og Nord-Amerika i denne slekten.
Samme år fant den kinesiske vitenskapsmannen T. Kan et tidligere ukjent treslag sørøst for Wanzhou uten å samle inn materiale, og i 1944 samlet forstmannen T. Wang inn materiale fra samme sted. Wang trodde først at dreide seg om en art i slekten Glyptostrobus, men etter at materialet ble undersøkt av eksperter i 1945 kunne en fastslå at det dreide seg om en bartreslekt som tidligere var ukjent i Kina. I 1946 ble det sendt to ekspedisjoner til området som fant mange flere trær og samlet inn frø og annet materiale. Den formelle artsbeskrivelsen ble publisert i 1948. Funnet av dette levende fossilet vakte stor oppsikt, og frø ble sendt til botaniske hager rundt i verden.
Urtreet ble tidligere regnet til sumpsypressfamilien (Taxodiaceae), men genetiske og morfologiske studier viser at denne familien ikke er en naturlig gruppe. Urtre og alle andre arter i sumpsypressfamilien, unntatt skjermtre (Sciadopitys), er derfor flyttet til sypressfamilien (Cupressaceae). De nærmeste slektningene til urtreet er Sequoia og Sequoiadendron.
Planting
I Kina plantes det flere millioner urtrær hvert år. Treslaget blir også dyrket overalt ellers i tempererte strøk, men det utvikler seg best i områder med varm og fuktig sommer. Nesten alle trær utenom Kina stammer fra frø som ble samlet inn i 1947, og en har problemer med innavlsdepresjon. Urtreet tåler mye luftforurensning og egner seg godt til å plantes langs gater.
I Norge kan arten plantes i sørlige kyst- og fjordstrøk. Ett urtre står plantet i vestre del av Botanisk hage i Oslo og ett midt i parken ved den gamle hovedgården.
Fossiler
Omtrent tyve fossile arter er beskrevet, men en regner nå bare tre arter som gyldige: Metasequoia foxii, M. milleri og M. occidentalis. Det er funnet mange fossiler i Nord-Amerika og Eurasia fra tidsrommet tidlig senkritt til overgangen pliocen–pleistocen. I Europa er slekten bare kjent fra paleocen i Skottland og eocen på Svalbard. Metasequoia overlevde i Vest-Sibir og arktisk Canada til sen pliocen og i vestlige Georgia og Japan til sen pliocen–tidlig pleistocen. Utbredelsen ble redusert etter hvert som klimaet ble kaldere og tørrere. I Kina er det er ikke funnet fossiler fra pliocen eller pleistocen.
I paleocen og eocen var klimaet på jorda varmere enn i dag, og det vokste store skoger i Arktis. De største trærne hadde en høyde på og en stammediameter på . Lysforholdene var spesielle med lite intenst lys hele døgnet om sommeren og en mørketid der fotosyntese var umulig i mange måneder. Det viktigste treslaget i disse skogene var Metasequoia, og fossiler av slekten er funnet på Svalbard, Grønland og Axel Heibergs land i Canada. Eksperimenter tyder på at slekten tåler midnattssol bedre enn lerk (Larix) og sumpsypress (Taxodium). De to andre bartreslektene vokste også i den høyarktiske skogen og mister i likhet med Metasequoia nålene om vinteren.
Galleri
Referanser
Eksterne lenker
Sypressfamilien
Sterkt truede arter på IUCNs rødliste
Kinas endemiske flora | norwegian_bokmål | 0.519594 |
humans_closest_relatives_after_primates/Human_rights.txt |
Human rights are moral principles, or norms, for certain standards of human behaviour and are regularly protected as substantive rights in substantive law, municipal and international law. They are commonly understood as inalienable, fundamental rights "to which a person is inherently entitled simply because she or he is a human being" and which are "inherent in all human beings", regardless of their age, ethnic origin, location, language, religion, ethnicity, or any other status. They are applicable everywhere and at every time in the sense of being universal, and they are egalitarian in the sense of being the same for everyone. They are regarded as requiring empathy and the rule of law, and imposing an obligation on persons to respect the human rights of others; it is generally considered that they should not be taken away except as a result of due process based on specific circumstances.
The doctrine of human rights has been highly influential within international law and global and regional institutions. Actions by states and non-governmental organisations form a basis of public policy worldwide. The idea of human rights suggests that "if the public discourse of peacetime global society can be said to have a common moral language, it is that of human rights". The strong claims made by the doctrine of human rights continue to provoke considerable scepticism and debates about the content, nature and justifications of human rights to this day. The precise meaning of the term right is controversial and is the subject of continued philosophical debate. While there is consensus that human rights encompass a wide variety of rights, such as the right to a fair trial, protection against enslavement, prohibition of genocide, free speech, or a right to education, there is disagreement about which of these particular rights should be included within the general framework of human rights; some thinkers suggest that human rights should be a minimum requirement to avoid the worst-case abuses, while others see it as a higher standard. It has also been argued that human rights are "God-given", although this notion has been criticized.
Many of the basic ideas that animated the human rights movement developed in the aftermath of the Second World War and the events of the Holocaust, culminating in the adoption of the Universal Declaration of Human Rights in Paris by the United Nations General Assembly in 1948. Ancient peoples did not have the same modern-day conception of universal human rights. The true forerunner of human rights discourse was the concept of natural rights, which appeared as part of the medieval natural law tradition that became prominent during the European Enlightenment with such philosophers as John Locke, Francis Hutcheson, and Jean-Jacques Burlamaqui, and which featured prominently in the political discourse of the American Revolution and the French Revolution. From this foundation, the modern human rights arguments emerged over the latter half of the 20th century, possibly as a reaction to slavery, torture, genocide, and war crimes, as a realization of inherent human vulnerability and as being a precondition for the possibility of a just society. Human rights advocacy has continued into the early 21st century, centered around achieving greater economic and political freedom.
History
Main article: History of human rights
This section needs expansion with: More information about human rights prior to the Enlightenment. You can help by adding to it. (May 2022)
U.S. Declaration of Independence ratified by the Continental Congress on 4 July 1776
The concept of human rights has in some sense existed for centuries, although peoples have not always thought of universal human rights in the same way humans do today. Among the oldest evidence of human rights is the Cyrus Cylinder dated from 6th Century BCE, it had rights like no slavery, worship of your own religion, and racial equality.
The true forerunner of human rights discourse was the concept of natural rights which appeared as part of the medieval natural law tradition. This tradition was heavily influenced by the writings of St Paul's early Christian thinkers such as St Hilary of Poitiers, St Ambrose, and St Augustine. Augustine was among the earliest to examine the legitimacy of the laws of man, and attempt to define the boundaries of what laws and rights occur naturally based on wisdom and conscience, instead of being arbitrarily imposed by mortals, and if people are obligated to obey laws that are unjust.
This medieval tradition became prominent during the European Enlightenment. From this foundation, the modern human rights arguments emerged over the latter half of the 20th century. Magna Carta is an English charter originally issued in 1215 which influenced the development of the common law and many later constitutional documents related to human rights, such as the 1689 English Bill of Rights, the 1789 United States Constitution, and the 1791 United States Bill of Rights.
17th century English philosopher John Locke discussed natural rights in his work, identifying them as being "life, liberty, and estate (property)", and argued that such fundamental rights could not be surrendered in the social contract. In Britain in 1689, the English Bill of Rights and the Scottish Claim of Right each made a range of oppressive governmental actions, illegal. Two major revolutions occurred during the 18th century, in the United States (1776) and in France (1789), leading to the United States Declaration of Independence and the French Declaration of the Rights of Man and of the Citizen respectively, both of which articulated certain human rights. Additionally, the Virginia Declaration of Rights of 1776 encoded into law a number of fundamental civil rights and civil freedoms.
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of Happiness.— United States Declaration of Independence, 1776
1800 to World War I
Declaration of the Rights of Man and of the Citizen approved by the National Assembly of France, 26 August 1789
Philosophers such as Thomas Paine, John Stuart Mill, and Hegel expanded on the theme of universality during the 18th and 19th centuries. In 1831, William Lloyd Garrison wrote in a newspaper called The Liberator that he was trying to enlist his readers in "the great cause of human rights", so the term human rights probably came into use sometime between Paine's The Rights of Man and Garrison's publication. In 1849 a contemporary, Henry David Thoreau, wrote about human rights in his treatise On the Duty of Civil Disobedience which was later influential on human rights and civil rights thinkers. United States Supreme Court Justice David Davis, in his 1867 opinion for Ex Parte Milligan, wrote "By the protection of the law, human rights are secured; withdraw that protection and they are at the mercy of wicked rulers or the clamor of an excited people."
Many groups and movements have managed to achieve profound social changes over the course of the 20th century in the name of human rights. In Western Europe and North America, labour unions brought about laws granting workers the right to strike, establishing minimum work conditions and forbidding or regulating child labour. The women's rights movement succeeded in gaining for many women the right to vote. National liberation movements in many countries succeeded in driving out colonial powers. One of the most influential was Mahatma Gandhi's leadership of the Indian independence movement. Movements by long-oppressed racial and religious minorities succeeded in many parts of the world, among them the civil rights movement, and more recent diverse identity politics movements, on behalf of women and minorities in the United States.
The foundation of the International Committee of the Red Cross, the 1864 Lieber Code and the first of the Geneva Conventions in 1864 laid the foundations of International humanitarian law, to be further developed following the two World Wars.
Between World War I and World War II
The League of Nations was established in 1919 at the negotiations over the Treaty of Versailles following the end of World War I. The League's goals included disarmament, preventing war through collective security, settling disputes between countries through negotiation, diplomacy and improving global welfare. Enshrined in its Charter was a mandate to promote many of the rights which were later included in the Universal Declaration of Human Rights. The League of Nations had mandates to support many of the former colonies of the Western European colonial powers during their transition from colony to independent state. Established as an agency of the League of Nations, and now part of United Nations, the International Labour Organization also had a mandate to promote and safeguard certain of the rights later included in the Universal Declaration of Human Rights (UDHR):
the primary goal of the ILO today is to promote opportunities for women and men to obtain decent and productive work, in conditions of freedom, equity, security and human dignity.— Report by the Director General for the International Labour Conference 87th Session
After World War II
Universal Declaration of Human Rights
Main article: Universal Declaration of Human Rights
"It is not a treaty... [In the future, it] may well become the international Magna Carta." Eleanor Roosevelt with the Universal Declaration of Human Rights in 1949.
The Universal Declaration of Human Rights (UDHR) is a non-binding declaration adopted by the United Nations General Assembly in 1948, partly in response to the events of World War II. The UDHR urges member states to promote a number of human, civil, economic and social rights, asserting these rights are part of the "foundation of freedom, justice and peace in the world". The declaration was the first international legal effort to limit the behavior of states and make sure they did their duties to their citizens following the model of the rights-duty duality.
... recognition of the inherent dignity and of the equal and inalienable rights of all members of the human family is the foundation of freedom, justice and peace in the world— Preamble to the Universal Declaration of Human Rights, 1948
The UDHR was framed by members of the Human Rights Commission, with Eleanor Roosevelt as chair, who began to discuss an International Bill of Rights in 1947. The members of the Commission did not immediately agree on the form of such a bill of rights, and whether, or how, it should be enforced. The Commission proceeded to frame the UDHR and accompanying treaties, but the UDHR quickly became the priority. Canadian law professor John Humprey and French lawyer René Cassin were responsible for much of the cross-national research and the structure of the document respectively, where the articles of the declaration were interpretative of the general principle of the preamble. The document was structured by Cassin to include the basic principles of dignity, liberty, equality and brotherhood in the first two articles, followed successively by rights pertaining to individuals; rights of individuals in relation to each other and to groups; spiritual, public and political rights; and economic, social and cultural rights. The final three articles place, according to Cassin, rights in the context of limits, duties and the social and political order in which they are to be realized. Humphrey and Cassin intended the rights in the UDHR to be legally enforceable through some means, as is reflected in the third clause of the preamble:
Whereas it is essential, if man is not to be compelled to have recourse, as a last resort, to rebellion against tyranny and oppression, that human rights should be protected by the rule of law.— Preamble to the Universal Declaration of Human Rights, 1948
Some of the UDHR was researched and written by a committee of international experts on human rights, including representatives from all continents and all major religions, and drawing on consultation with leaders such as Mahatma Gandhi. The inclusion of both civil and political rights and economic, social, and cultural rights was predicated on the assumption that basic human rights are indivisible and that the different types of rights listed are inextricably linked. Although this principle was not opposed by any member states at the time of adoption (the declaration was adopted unanimously, with the abstention of the Soviet bloc, apartheid South Africa, and Saudi Arabia), this principle was later subject to significant challenges. On the issue of the term universal, the declarations did not apply to domestic discrimination or racism. Henry J. Richardson III argued:
All major governments at the time of drafting the U.N. charter and the Universal declaration did their best to ensure, by all means known to domestic and international law, that these principles had only international application and carried no legal obligation on those governments to be implemented domestically. All tacitly realized that for their own discriminated-against minorities to acquire leverage on the basis of legally being able to claim enforcement of these wide-reaching rights would create pressures that would be political dynamite.
The onset of the Cold War soon after the UDHR was conceived brought to the fore divisions over the inclusion of both economic and social rights and civil and political rights in the declaration. Capitalist states tended to place strong emphasis on civil and political rights (such as freedom of association and expression), and were reluctant to include economic and social rights (such as the right to work and the right to join a union). Socialist states placed much greater importance on economic and social rights and argued strongly for their inclusion. Because of the divisions over which rights to include and because some states declined to ratify any treaties including certain specific interpretations of human rights, and despite the Soviet bloc and a number of developing countries arguing strongly for the inclusion of all rights in a Unity Resolution, the rights enshrined in the UDHR were split into two separate covenants, allowing states to adopt some rights and derogate others. Although this allowed the covenants to be created, it denied the proposed principle that all rights are linked, which was central to some interpretations of the UDHR. Although the UDHR is a non-binding resolution, it is now considered to be a central component of international customary law which may be invoked under appropriate circumstances by state judiciaries and other judiciaries.
Human Rights Treaties
In 1966, the International Covenant on Civil and Political Rights (ICCPR) and the International Covenant on Economic, Social and Cultural Rights (ICESCR) were adopted by the United Nations, between them making the rights contained in the UDHR binding on all states. They came into force only in 1976, when they were ratified by a sufficient number of countries (despite achieving the ICCPR, a covenant including no economic or social rights, the US only ratified the ICCPR in 1992). The ICESCR commits 155 state parties to work toward the granting of economic, social, and cultural rights (ESCR) to individuals.
Numerous other treaties (pieces of legislation) have been offered at the international level. They are generally known as human rights instruments. Some of the most significant are:
Convention on the Prevention and Punishment of the Crime of Genocide (adopted 1948, entry into force: 1951) unhchr.ch
Convention on the Elimination of All Forms of Racial Discrimination (CERD) (adopted 1966, entry into force: 1969) unhchr.ch
Convention on the Elimination of All Forms of Discrimination Against Women (CEDAW) (entry into force: 1981) Convention on the Elimination of All Forms of Discrimination against Women
United Nations Convention Against Torture (CAT) (adopted 1984, entry into force: 1984)
Convention on the Rights of the Child (CRC) (adopted 1989, entry into force: 1989) Convention on the Rights of the Child | UNICEF Archived 26 April 2019 at the Wayback Machine
International Convention on the Protection of the Rights of All Migrant Workers and Members of their Families (ICRMW) (adopted 1990)
Rome Statute of the International Criminal Court (ICC) (entry into force: 2002)
In 2022, the United Nations General Assembly passed a resolution declaring that everyone on the planet has a right to a healthy environment, including clean air, clean water, and a stable climate.
Promotion strategies
Military force
See also: R2p and Peacekeeping
Responsibility to protect refers to a doctrine for United Nations member states to intervene to protect populations from atrocities. It has been cited as justification in the use of recent military interventions. An example of an intervention that is often criticized is the 2011 military intervention in the First Libyan Civil War by NATO and Qatar where the goal of preventing atrocities is alleged to have taken upon itself the broader mandate of removing the target government.
Economic actions
See also: Economic sanctions
Economic sanctions are often levied upon individuals or states who commit human rights violations. Sanctions are often criticized for its feature of collective punishment in hurting a country's population economically in order dampen that population's view of its government. It is also argued that, counterproductively, sanctions on offending authoritarian governments strengthen that government's position domestically as governments would still have more mechanisms to find funding than their critics and opposition, who become further weakened.
The risk of human rights violations increases with the increase in financially vulnerable populations. Girls from poor families in non-industrialized economies are often viewed as a financial burden on the family and marriage of young girls is often driven in the hope that daughters will be fed and protected by wealthier families. Female genital mutilation and force-feeding of daughters is argued to be similarly driven in large part to increase their marriage prospects and thus their financial security by achieving certain idealized standards of beauty. In certain areas, girls requiring the experience of sexual initiation rites with men and passing sex training tests on girls are designed to make them more appealing as marriage prospects. Measures to help the economic status of vulnerable groups in order to reduce human rights violations include girls' education and guaranteed minimum incomes and conditional cash transfers, such as Bolsa familia which subsidize parents who keep children in school rather than contributing to family income, has successfully reduced child labor.
Informational strategies
See also: Human rights education and Activism
Human rights abuses are monitored by United Nations committees, national institutions and governments and by many independent non-governmental organizations, such as Amnesty International, Human Rights Watch, World Organisation Against Torture, Freedom House, International Freedom of Expression Exchange and Anti-Slavery International. These organisations collect evidence and documentation of human rights abuses and apply pressure to promote human rights. Educating people on the concept of human rights has been argued as a strategy to prevent human rights abuses.
Legal instruments
Many examples of legal instruments at the international, regional and national level described below are designed to enforce laws securing human rights.
Protection at the international level
Main article: International human rights instruments
United Nations
Main article: United Nations
The UN General Assembly
The United Nations (UN) is the only multilateral governmental agency with universally accepted international jurisdiction for universal human rights legislation. All UN organs have advisory roles to the United Nations Security Council and the United Nations Human Rights Council, and there are numerous committees within the UN with responsibilities for safeguarding different human rights treaties. The most senior body of the UN with regard to human rights is the Office of the High Commissioner for Human Rights. The United Nations has an international mandate to:
... achieve international co-operation in solving international problems of an economic, social, cultural, or humanitarian character, and in promoting and encouraging respect for human rights and for fundamental freedoms for all without distinction as to race, sex, language, or religion.— Article 1–3 of the Charter of the United Nations
Human Rights Council
Main article: United Nations Human Rights Council
The UN Human Rights Council, created in 2005, has a mandate to investigate alleged human rights violations. 47 of the 193 UN member states sit on the council, elected by simple majority in a secret ballot of the United Nations General Assembly. Members serve a maximum of six years and may have their membership suspended for gross human rights abuses. The council is based in Geneva, and meets three times a year; with additional meetings to respond to urgent situations. Independent experts (rapporteurs) are retained by the council to investigate alleged human rights abuses and to report to the council. The Human Rights Council may request that the Security Council refer cases to the International Criminal Court (ICC) even if the issue being referred is outside the normal jurisdiction of the ICC.
United Nations treaty bodies
Main article: Treaty body
In addition to the political bodies whose mandate flows from the UN charter, the UN has set up a number of treaty-based bodies, comprising committees of independent experts who monitor compliance with human rights standards and norms flowing from the core international human rights treaties. They are supported by and are created by the treaty that they monitor, With the exception of the CESCR, which was established under a resolution of the Economic and Social Council to carry out the monitoring functions originally assigned to that body under the Covenant, they are technically autonomous bodies, established by the treaties that they monitor and accountable to the state parties of those treaties – rather than subsidiary to the United Nations, though in practice they are closely intertwined with the United Nations system and are supported by the UN High Commissioner for Human Rights (UNHCHR) and the UN Centre for Human Rights.
The Human Rights Committee promotes participation with the standards of the ICCPR. The members of the committee express opinions on member countries and make judgments on individual complaints against countries which have ratified an Optional Protocol to the treaty. The judgments, termed "views", are not legally binding. The member of the committee meets around three times a year to hold sessions
The Committee on Economic, Social and Cultural Rights monitors the ICESCR and makes general comments on ratifying countries performance. It will have the power to receive complaints against the countries that opted into the Optional Protocol once it has come into force. Unlike the other treaty bodies, the economic committee is not an autonomous body responsible to the treaty parties, but directly responsible to the Economic and Social Council and ultimately to the General Assembly. This means that the Economic Committee faces particular difficulties at its disposal only relatively "weak" means of implementation in comparison to other treaty bodies. Particular difficulties noted by commentators include: perceived vagueness of the principles of the treaty, relative lack of legal texts and decisions, ambivalence of many states in addressing economic, social and cultural rights, comparatively few non-governmental organisations focused on the area and problems with obtaining relevant and precise information.
The Committee on the Elimination of Racial Discrimination monitors the CERD and conducts regular reviews of countries' performance. It can make judgments on complaints against member states allowing it, but these are not legally binding. It issues warnings to attempt to prevent serious contraventions of the convention.
The Committee on the Elimination of Discrimination against Women monitors the CEDAW. It receives states' reports on their performance and comments on them, and can make judgments on complaints against countries which have opted into the 1999 Optional Protocol.
The Committee Against Torture monitors the CAT and receives states' reports on their performance every four years and comments on them. Its subcommittee may visit and inspect countries which have opted into the Optional Protocol.
The Committee on the Rights of the Child monitors the CRC and makes comments on reports submitted by states every five years. It does not have the power to receive complaints.
The Committee on Migrant Workers was established in 2004 and monitors the ICRMW and makes comments on reports submitted by states every five years. It will have the power to receive complaints of specific violations only once ten member states allow it.
The Committee on the Rights of Persons with Disabilities was established in 2008 to monitor the Convention on the Rights of Persons with Disabilities. It has the power to receive complaints against the countries which have opted into the Optional Protocol to the Convention on the Rights of Persons with Disabilities.
The Committee on Enforced Disappearances monitors the ICPPED. All States parties are obliged to submit reports to the committee on how the rights are being implemented. The Committee examines each report and addresses its concerns and recommendations to the State party in the form of "concluding observations".
Each treaty body receives secretariat support from the Human Rights Council and Treaties Division of Office of the High Commissioner on Human Rights (OHCHR) in Geneva except CEDAW, which is supported by the Division for the Advancement of Women (DAW). CEDAW formerly held all its sessions at United Nations headquarters in New York but now frequently meets at the United Nations Office in Geneva; the other treaty bodies meet in Geneva. The Human Rights Committee usually holds its March session in New York City. The human rights enshrined in the UDHR, the Geneva Conventions and the various enforced treaties of the United Nations are enforceable in law. In practice, many rights are very difficult to legally enforce due to the absence of consensus on the application of certain rights, the lack of relevant national legislation or of bodies empowered to take legal action to enforce them.
International courts
The official logo of the ICC
There exist a number of internationally recognized organisations with worldwide mandate or jurisdiction over certain aspects of human rights:
The International Court of Justice (ICJ) is the United Nations' primary judiciary body. It has worldwide jurisdiction. It is directed by the Security Council. The ICJ settles disputes between nations. The ICJ does not have jurisdiction over individuals.
The International Criminal Court (ICC) is the body responsible for investigating and punishing war crimes, and crimes against humanity when such occur within its jurisdiction, with a mandate to bring to justice perpetrators of such crimes that occurred after its creation in 2002. A number of UN members have not joined the court and the ICC does not have jurisdiction over their citizens, and others have signed but not yet ratified the Rome Statute, which established the court.
The ICC and other international courts (see Regional human rights below) exist to take action where the national legal system of a state is unable to try the case itself. If national law is able to safeguard human rights and punish those who breach human rights legislation, it has primary jurisdiction by complementarity. Only when all local remedies have been exhausted does international law take effect.
Regional human rights regimes
See also: List of human rights articles by country, National human rights institutions, and Human rights commission
In over 110 countries, national human rights institutions (NHRIs) have been set up to protect, promote or monitor human rights with jurisdiction in a given country. Although not all NHRIs are compliant with the Paris Principles, the number and effect of these institutions is increasing. The Paris Principles were defined at the first International Workshop on National Institutions for the Promotion and Protection of Human Rights in Paris on 7–9 October 1991, and adopted by United Nations Human Rights Commission Resolution 1992/54 of 1992 and the General Assembly Resolution 48/134 of 1993. The Paris Principles list a number of responsibilities for national institutions.
Africa
Flag of the African Union
Main article: Human rights in Africa
The African Union (AU) is a continental union consisting of fifty-five African states. Established in 2001, the AU's purpose is to help secure Africa's democracy, human rights, and a sustainable economy, especially by bringing an end to intra-African conflict and creating an effective common market. The African Commission on Human and Peoples' Rights (ACHPR) is a quasi-judicial organ of the African Union tasked with promoting and protecting human rights and collective (peoples') rights throughout the African continent as well as interpreting the African Charter on Human and Peoples' Rights and considering individual complaints of violations of the Charter. The commission has three broad areas of responsibility:
Promoting human and peoples' rights
Protecting human and peoples' rights
Interpreting the African Charter on Human and Peoples' Rights
In pursuit of these goals, the commission is mandated to "collect documents, undertake studies and researches on African problems in the field of human and peoples, rights, organise seminars, symposia and conferences, disseminate information, encourage national and local institutions concerned with human and peoples' rights and, should the case arise, give its views or make recommendations to governments" (Charter, Art. 45).
With the creation of the African Court on Human and Peoples' Rights (under a protocol to the Charter which was adopted in 1998 and entered into force in January 2004), the commission will have the additional task of preparing cases for submission to the Court's jurisdiction. In a July 2004 decision, the AU Assembly resolved that the future Court on Human and Peoples' Rights would be integrated with the African Court of Justice. The Court of Justice of the African Union is intended to be the "principal judicial organ of the Union" (Protocol of the Court of Justice of the African Union, Article 2.2). Although it has not yet been established, it is intended to take over the duties of the African Commission on Human and Peoples' Rights, as well as act as the supreme court of the African Union, interpreting all necessary laws and treaties. The Protocol establishing the African Court on Human and Peoples' Rights entered into force in January 2004, but its merging with the Court of Justice has delayed its establishment. The Protocol establishing the Court of Justice will come into force when ratified by 15 countries.
There are many countries in Africa accused of human rights violations by the international community and NGOs.
Americas
The Organization of American States (OAS) is an international organization, headquartered in Washington, D.C., United States. Its members are the thirty-five independent states of the Americas. Over the course of the 1990s, with the end of the Cold War, the return to democracy in Latin America, and the thrust toward globalization, the OAS made major efforts to reinvent itself to fit the new context. Its stated priorities now include the following:
Strengthening democracy
Working for peace
Protecting human rights
Combating corruption
The rights of Indigenous Peoples
Promoting sustainable development
The Inter-American Commission on Human Rights (the IACHR) is an autonomous organ of the Organization of American States, also based in Washington, D.C. Along with the Inter-American Court of Human Rights, based in San José, Costa Rica, it is one of the bodies that comprise the inter-American system for the promotion and protection of human rights. The IACHR is a permanent body which meets in regular and special sessions several times a year to examine allegations of human rights violations in the hemisphere. Its human rights duties stem from three documents:
the American Convention on Human Rights
the American Declaration of the Rights and Duties of Man
the Charter of the Organization of American States
The Inter-American Court of Human Rights was established in 1979 with the purpose of enforcing and interpreting the provisions of the American Convention on Human Rights. Its two main functions are thus adjudicatory and advisory. Under the former, it hears and rules on the specific cases of human rights violations referred to it. Under the latter, it issues opinions on matters of legal interpretation brought to its attention by other OAS bodies or member states.
Asia
Main articles: Human rights in Asia, Human rights in East Asia, Human rights in Central Asia, and Human Rights in the Middle East
There are no Asia-wide organisations or conventions to promote or protect human rights. Countries vary widely in their approach to human rights and their record of human rights protection. The Association of Southeast Asian Nations (ASEAN) is a geo-political and economic organization of 10 countries located in Southeast Asia, which was formed in 1967 by Indonesia, Malaysia, the Philippines, Singapore and Thailand. The organisation now also includes Brunei Darussalam, Vietnam, Laos, Myanmar and Cambodia. In October 2009, the ASEAN Intergovernmental Commission on Human Rights was inaugurated, and subsequently, the ASEAN Human Rights Declaration was adopted unanimously by ASEAN members on 18 November 2012.
The Arab Charter on Human Rights (ACHR) was adopted by the Council of the League of Arab States on 22 May 2004.
Europe
European Court of Human Rights in Strasbourg
Main article: Human rights in Europe
See also: Human rights in the Soviet Union
The Council of Europe, founded in 1949, is the oldest organisation working for European integration. It is an international organisation with legal personality recognised under public international law and has observer status with the United Nations. The seat of the Council of Europe is in Strasbourg in France. The Council of Europe is responsible for both the European Convention on Human Rights and the European Court of Human Rights. These institutions bind the council's members to a code of human rights which, though strict, are more lenient than those of the United Nations charter on human rights. The council also promotes the European Charter for Regional or Minority Languages and the European Social Charter. Membership is open to all European states which seek European integration, accept the principle of the rule of law and are able and willing to guarantee democracy, fundamental human rights and freedoms.
The Council of Europe is an organisation that is not part of the European Union, but the latter is expected to accede to the European Convention and potentially the Council itself. The EU has its own human rights document; the Charter of Fundamental Rights of the European Union. The European Convention on Human Rights defines and guarantees since 1950 human rights and fundamental freedoms in Europe. All 47 member states of the Council of Europe have signed this convention and are therefore under the jurisdiction of the European Court of Human Rights in Strasbourg. In order to prevent torture and inhuman or degrading treatment (Article 3 of the convention), the European Committee for the Prevention of Torture was established.
Philosophies of human rights
Rights
Theoretical distinctions
Claim rights and liberty rights
Individual and group rights
Natural rights and legal rights
Negative and positive rights
Human rights
Civil and political
Economic, social and cultural
Three generations
Rights by beneficiary
Accused
Animals
Children
Consumers
Creditors
Deaf
Disabled
Elders
Farmers
Fetuses
Humans
Indigenous
Intersex
Kings
LGBT
Transgender
Men
Minorities
Parents
Fathers
Mothers
Patients
Peasants
Plants
Prisoners
Robots
States
Students
Victims
Women
Workers
Youth
Other groups of rights
Assembly
Association
Asylum
Civil liberties
Digital
Education
Fair trial
Food
Free migration
Health
Housing
Linguistic
Movement
Development
Property
Repair
Reproductive
Rest and leisure
Self defense
Self-determination of people
Sexuality
Speech
Water and sanitation
vte
Several theoretical approaches have been advanced to explain how and why human rights become part of social expectations. One of the oldest Western philosophies on human rights is that they are a product of a natural law, stemming from different philosophical or religious grounds. Other theories hold that human rights codify moral behavior which is a human social product developed by a process of biological and social evolution (associated with David Hume). Human rights are also described as a sociological pattern of rule setting (as in the sociological theory of law and the work of Max Weber). These approaches include the notion that individuals in a society accept rules from legitimate authority in exchange for security and economic advantage (as in John Rawls) – a social contract.
Natural rights
Main articles: Natural law and Natural rights
Natural law theories base human rights on a "natural" moral, religious or even biological order which is independent of transitory human laws or traditions. Socrates and his philosophic heirs, Plato and Aristotle, posited the existence of natural justice or natural right (dikaion physikon, δικαιον φυσικον, Latin ius naturale). Of these, Aristotle is often said to be the father of natural law, although evidence for this is due largely to the interpretations of his work by Thomas Aquinas. The development of this tradition of natural justice into one of natural law is usually attributed to the Stoics.
Some of the early Church fathers sought to incorporate the until then pagan concept of natural law into Christianity. Natural law theories have featured greatly in the philosophies of Thomas Aquinas, Francisco Suárez, Richard Hooker, Thomas Hobbes, Hugo Grotius, Samuel von Pufendorf, and John Locke. In the 17th century, Thomas Hobbes founded a contractualist theory of legal positivism on what all men could agree upon: what they sought (happiness) was subject to contention, but a broad consensus could form around what they feared (violent death at the hands of another). The natural law was how a rational human being, seeking to survive and prosper, would act. It was discovered by considering humankind's natural rights, whereas previously it could be said that natural rights were discovered by considering the natural law. In Hobbes' opinion, the only way natural law could prevail was for men to submit to the commands of the sovereign. In this lay the foundations of the theory of a social contract between the governed and the governor.
Hugo Grotius based his philosophy of international law on natural law. He wrote that "even the will of an omnipotent being cannot change or abrogate" natural law, which "would maintain its objective validity even if we should assume the impossible, that there is no God or that he does not care for human affairs." (De iure belli ac pacis, Prolegomeni XI). This is the famous argument etiamsi daremus (non-esse Deum), that made natural law no longer dependent on theology. John Locke incorporated natural law into many of his theories and philosophy, especially in Two Treatises of Government. Locke turned Hobbes' prescription around, saying that if the ruler went against natural law and failed to protect "life, liberty, and property," people could justifiably overthrow the existing state and create a new one.
The Belgian philosopher of law Frank van Dun is one among those who are elaborating a secular conception of natural law in the liberal tradition. There are also emerging and secular forms of natural law theory that define human rights as derivative of the notion of universal human dignity. The term "human rights" has replaced the term "natural rights" in popularity, because the rights are less and less frequently seen as requiring natural law for their existence.
Other theories of human rights
The philosopher John Finnis argues that human rights are justifiable on the grounds of their instrumental value in creating the necessary conditions for human well-being. Interest theories highlight the duty to respect the rights of other individuals on grounds of self-interest:
Human rights law, applied to a State's own citizens serves the interest of states, by, for example, minimizing the risk of violent resistance and protest and by keeping the level of dissatisfaction with the government manageable— Niraj Nathwani, Rethinking Refugee Law
The biological theory considers the comparative reproductive advantage of human social behavior based on empathy and altruism in the context of natural selection. The philosopher Zhao Tingyang argues that the traditional human rights framework fails to be universal, because it arose from contingent aspects of Western culture, and that the concept of inalienable and unconditional human rights is in tension with the principle of justice. He proposes an alternative framework called "credit human rights", in which rights are tied to responsibilities.
Concepts in human rights
See also: Human Rights Law
Indivisibility and categorization of rights
The most common categorization of human rights is to split them into civil and political rights, and economic, social and cultural rights. Civil and political rights are enshrined in articles 3 to 21 of the Universal Declaration of Human Rights and in the ICCPR. Economic, social and cultural rights are enshrined in articles 22 to 28 of the Universal Declaration of Human Rights and in the ICESCR. The UDHR included both economic, social and cultural rights and civil and political rights because it was based on the principle that the different rights could only successfully exist in combination:
The ideal of free human beings enjoying civil and political freedom and freedom from fear and want can only be achieved if conditions are created whereby everyone may enjoy his civil and political rights, as well as his social, economic and cultural rights— International Covenant on Civil and Political Rights and the International Covenant on Economic Social and Cultural Rights, 1966
This is held to be true because without civil and political rights the public cannot assert their economic, social and cultural rights. Similarly, without livelihoods and a working society, the public cannot assert or make use of civil or political rights (known as the full belly thesis).
Although accepted by the signatories to the UDHR, most of them do not in practice give equal weight to the different types of rights. Western cultures have often given priority to civil and political rights, sometimes at the expense of economic and social rights such as the right to work, to education, health and housing. For example, in the United States there is no universal access to healthcare free at the point of use. That is not to say that Western cultures have overlooked these rights entirely (the welfare states that exist in Western Europe are evidence of this). Similarly, the ex Soviet bloc countries and Asian countries have tended to give priority to economic, social and cultural rights, but have often failed to provide civil and political rights.
Another categorization, offered by Karel Vasak, is that there are three generations of human rights: first-generation civil and political rights (right to life and political participation), second-generation economic, social and cultural rights (right to subsistence) and third-generation solidarity rights (right to peace, right to clean environment). Out of these generations, the third generation is the most debated and lacks both legal and political recognition. This categorisation is at odds with the indivisibility of rights, as it implicitly states that some rights can exist without others. Prioritisation of rights for pragmatic reasons is however a widely accepted necessity. Human rights expert Philip Alston argues:
If every possible human rights element is deemed to be essential or necessary, then nothing will be treated as though it is truly important.— Philip Alston
He, and others, urge caution with prioritisation of rights:
... the call for prioritizing is not to suggest that any obvious violations of rights can be ignored.— Philip Alston
Priorities, where necessary, should adhere to core concepts (such as reasonable attempts at progressive realization) and principles (such as non-discrimination, equality and participation.— Olivia Ball, Paul Gready
Some human rights are said to be "inalienable rights". The term inalienable rights (or unalienable rights) refers to "a set of human rights that are fundamental, are not awarded by human power, and cannot be surrendered".
The adherence to the principle of indivisibility by the international community was reaffirmed in 1995:
All human rights are universal, indivisible and interdependent and related. The international community must treat human rights globally in a fair and equal manner, on the same footing, and with the same emphasis.— Vienna Declaration and Program of Action, World Conference on Human Rights, 1995
This statement was again endorsed at the 2005 World Summit in New York (paragraph 121).
Universalism vs cultural relativism
Main articles: Cultural relativism, Moral relativism, Moral universalism, and Universal ethic
Map: Estimated prevalence of Female Genital Cutting (FGC) in Africa. Data based on uncertain estimates.
The Universal Declaration of Human Rights enshrines, by definition, rights that apply to all humans equally, whichever geographical location, state, race or culture they belong to. Proponents of cultural relativism suggest that human rights are not all universal, and indeed conflict with some cultures and threaten their survival. Rights which are most often contested with relativistic arguments are the rights of women. For example, female genital mutilation occurs in different cultures in Africa, Asia and South America. It is not mandated by any religion, but has become a tradition in many cultures. It is considered a violation of women's and girl's rights by much of the international community, and is outlawed in some countries.
Universalism has been described by some as cultural, economic or political imperialism. In particular, the concept of human rights is often claimed to be fundamentally rooted in a politically liberal outlook which, although generally accepted in Europe, Japan or North America, is not necessarily taken as standard elsewhere. For example, in 1981, the Iranian representative to the United Nations, Said Rajaie-Khorassani, articulated the position of his country regarding the UDHR by saying that the UDHR was "a secular understanding of the Judeo-Christian tradition", which could not be implemented by Muslims without trespassing the Islamic law. The former Prime Ministers of Singapore, Lee Kuan Yew, and of Malaysia, Mahathir bin Mohamad both claimed in the 1990s that Asian values were significantly different from western values and included a sense of loyalty and foregoing personal freedoms for the sake of social stability and prosperity, and therefore authoritarian government is more appropriate in Asia than democracy. This view is countered by Mahathir's former deputy:
To say that freedom is Western or unAsian is to offend our traditions as well as our forefathers, who gave their lives in the struggle against tyranny and injustices.— Anwar Ibrahim, in his keynote speech to the Asian Press Forum title Media and Society in Asia, 2 December 1994
Singapore's opposition leader Chee Soon Juan also states that it is racist to assert that Asians do not want human rights. An appeal is often made to the fact that influential human rights thinkers, such as John Locke and John Stuart Mill, have all been Western and indeed that some were involved in the running of Empires themselves. Relativistic arguments tend to neglect the fact that modern human rights are new to all cultures, dating back no further than the UDHR in 1948. They also do not account for the fact that the UDHR was drafted by people from many different cultures and traditions, including a US Roman Catholic, a Chinese Confucian philosopher, a French Zionist and a representative from the Arab League, amongst others, and drew upon advice from thinkers such as Mahatma Gandhi.
Michael Ignatieff has argued that cultural relativism is almost exclusively an argument used by those who wield power in cultures which commit human rights abuses, and that those whose human rights are compromised are the powerless. This reflects the fact that the difficulty in judging universalism versus relativism lies in who is claiming to represent a particular culture. Although the argument between universalism and relativism is far from complete, it is an academic discussion in that all international human rights instruments adhere to the principle that human rights are universally applicable. The 2005 World Summit reaffirmed the international community's adherence to this principle:
The universal nature of human rights and freedoms is beyond question.— 2005 World Summit, paragraph 120
Universal jurisdiction vs state sovereignty
See also: Universal jurisdiction and State sovereignty
Universal jurisdiction is a controversial principle in international law whereby states claim criminal jurisdiction over persons whose alleged crimes were committed outside the boundaries of the prosecuting state, regardless of nationality, country of residence, or any other relation with the prosecuting country. The state backs its claim on the grounds that the crime committed is considered a crime against all, which any state is authorized to punish. The concept of universal jurisdiction is therefore closely linked to the idea that certain international norms are erga omnes, or owed to the entire world community, as well as the concept of jus cogens. In 1993, Belgium passed a law of universal jurisdiction to give its court's jurisdiction over crimes against humanity in other countries, and in 1998 Augusto Pinochet was arrested in London following an indictment by Spanish judge Baltasar Garzón under the universal jurisdiction principle. The principle is supported by Amnesty International and other human rights organisations as they believe certain crimes pose a threat to the international community as a whole and the community has a moral duty to act, but others, including Henry Kissinger, argue that state sovereignty is paramount, because breaches of rights committed in other countries are outside states' sovereign interest and because states could use the principle for political reasons.
State and non-state actors
Companies, NGOs, political parties, informal groups, and individuals are known as non-State actors. Non-State actors can also commit human rights abuses, but are not subject to human rights law other than International Humanitarian Law, which applies to individuals. Multinational companies play an increasingly large role in the world, and are responsible for a large number of human rights abuses. Although the legal and moral environment surrounding the actions of governments is reasonably well developed, that surrounding multinational companies is both controversial and ill-defined. Multinational companies often view their primary responsibility as being to their shareholders, not to those affected by their actions. Such companies are often larger than the economies of the states in which they operate, and can wield significant economic and political power. No international treaties exist to specifically cover the behavior of companies with regard to human rights, and national legislation is very variable. Jean Ziegler, Special Rapporteur of the UN Commission on Human Rights on the right to food stated in a report in 2003:
the growing power of transnational corporations and their extension of power through privatization, deregulation and the rolling back of the State also mean that it is now time to develop binding legal norms that hold corporations to human rights standards and circumscribe potential abuses of their position of power.— Jean Ziegler
In August 2003, the Human Rights Commission's Sub-Commission on the Promotion and Protection of Human Rights produced draft Norms on the responsibilities of transnational corporations and other business enterprises with regard to human rights. These were considered by the Human Rights Commission in 2004, but have no binding status on corporations and are not monitored. Additionally, the United Nations Sustainable Development Goal 10 aims to substantially reduce inequality by 2030 through the promotion of appropriate legislation.
Human rights in emergency situations
Extrajudicial detention of captives in Guantanamo Bay
See also: Derogation, National security, and Anti-terrorism legislation
With the exception of non-derogable human rights (international conventions class the right to life, the right to be free from slavery, the right to be free from torture and the right to be free from retroactive application of penal laws as non-derogable), the UN recognises that human rights can be limited or even pushed aside during times of national emergency, although it clarifies:
the emergency must be actual, affect the whole population and the threat must be to the very existence of the nation. The declaration of emergency must also be a last resort and a temporary measure— United Nations, The Resource
Rights that cannot be derogated for reasons of national security in any circumstances are known as peremptory norms or jus cogens. Such International law obligations are binding on all states and cannot be modified by treaty.
Criticism
See also: Human rights inflation
Critics of the view that human rights are universal argue that human rights are a Western concept that "emanate from a European, Judeo-Christian, and/or Enlightenment heritage (typically labeled Western) and cannot be enjoyed by other cultures that don't emulate the conditions and values of 'Western' societies." Right-wing critics of human rights argue that they are "unrealistic and unenforceable norms and inappropriate intrusions on state sovereignty", while left-wing critics of human rights argue that they fail "to achieve – or prevents better approaches to achieving – progressive goals".
See also
Animal rights
Civil liberties
Deaf rights movement
Disability rights movement
Discrimination
Human right to water and sanitation
Labor rights
LGBT rights by country or territory
List of human rights organisations
List of human rights awards
Minority rights
Needs
Prisoners' rights
Righteousness
Welfare rights
Explanatory notes
^ This does not include the Vatican, which although recognised as an independent state, is not a member of the UN.
^ The Security Council referred the human rights situation in Darfur in Sudan to the ICC despite the fact that Sudan has a functioning legal system.
Notes
^ James Nickel, with assistance from Thomas Pogge, M.B.E. Smith, and Leif Wenar, 13 December 2013, Stanford Encyclopedia of Philosophy, Human Rights Archived 5 August 2019 at the Wayback Machine. Retrieved 14 August 2014
^ Nickel (2010).
^ The United Nations, Office of the High Commissioner of Human Rights, What are human rights? Archived 19 August 2014 at the Wayback Machine. Retrieved 14 August 2014
^ Sepulveda et al. (2004), p. 3.
^ Burns H. Weston, 20 March 2014, Encyclopædia Britannica, human rights Archived 18 May 2015 at the Wayback Machine. Retrieved 14 August 2014.
^ Gary J. Bass (book reviewer), Samuel Moyn (author of book being reviewed), 20 October 2010, The New Republic, The Old New Thing Archived 12 September 2015 at the Wayback Machine. Retrieved 14 August 2014
^ Beitz (2009), p. 1.
^ Shaw (2008), p. 265.
^ Macmillan Dictionary, human rights – definition Archived 19 August 2014 at the Wayback Machine. Retrieved 14 August 2014, "the rights that everyone should have in a society, including the right to express opinions about the government or to have protection from harm"
^ International technical guidance on sexuality education: an evidence-informed approach (PDF). Paris: UNESCO. 2018. p. 16. ISBN 978-9231002595. Archived (PDF) from the original on 13 November 2018. Retrieved 23 February 2018.
^ Niose, David (6 October 2016). "The Danger of Claiming That Rights Come From God". Psychology Today. Retrieved 18 May 2022.
^ Simmons, Beth A. (2009). Mobilizing for Human Rights: International Law in Domestic Politics. Cambridge University Press. p. 23. ISBN 978-1139483483.
^ Freeman (2002), pp. 15–17.
^ Moyn (2010), p. 8.
^ Sutto, Marco (2019). "Human Rights Evolution, A Brief History". The CoESPU Magazine. 2019 (3): 18–21. doi:10.32048/Coespumagazine3.19.3. Archived from the original on 6 March 2023. Retrieved 6 March 2023.
^ "A Short History of Human Rights". Archived from the original on 6 March 2023. Retrieved 6 March 2023.
^ "International Human Rights Law: A Short History". Archived from the original on 14 March 2023. Retrieved 6 March 2023.
^ "History of Natural Law & Basic Freedoms, Cyrus the Great". Archived from the original on 20 March 2023. Retrieved 20 March 2023.
^ Carlyle, A. J. (1903). A History of Medieval Political Theory in the West. Vol. 1. New York: G.P. Putnam's Sons. p. 83. Archived from the original on 8 June 2016.
^ "Augustine on Law and Order — Lawexplores.com".
^ Hazeltine, H. D. (1917). "The Influence of Magna Carta on American Constitutional Development". In Malden, Henry Elliot (ed.). Magna Carta commemoration essays. BiblioBazaar. ISBN 978-1116447477.
^ "Britain's unwritten constitution". British Library. Archived from the original on 8 September 2021. Retrieved 27 November 2015. The key landmark is the Bill of Rights (1689), which established the supremacy of Parliament over the Crown ... providing for the regular meeting of Parliament, free elections to the Commons, free speech in parliamentary debates, and some basic human rights, most famously freedom from 'cruel or unusual punishment.
^ Mayer (2000), p. 110.
^ "Ex Parte Milligan, 71 U.S. 2, 119. (full text)" (PDF). December 1866. Archived from the original (PDF) on 7 March 2008. Retrieved 28 December 2007.
^ Crenshaw, Kimberle (1991). "Mapping the Margins: Intersectionality, Identity Politics, and Violence against Women of Color". Stanford Law Review. 43 (6): 1241–1299. doi:10.2307/1229039. ISSN 0038-9765. JSTOR 1229039.
^ Eleanor Roosevelt: Address to the United Nations General Assembly Archived 22 June 2017 at the Wayback Machine 10 December 1948 in Paris, France
^ (A/RES/217, 10 December 1948 at Palais de Chaillot, Paris)
^ Glendon, Mary Ann (July 2004). "The Rule of Law in The Universal Declaration of Human Rights". Northwestern University Journal of International Human Rights. 2 (5). Archived from the original on 20 July 2011. Retrieved 7 January 2008.
^ Glendon (2001).
^ Ball & Gready (2007), p. 34.
^ Paul Gordon Lauren, "First Principles of Racial Equality: History and the Politics and Diplomacy of Human Rights Provisions in the United Nations Charter", Human Rights Quarterly 5 (1983): 1–26.
^ Henry J. Richardson III, "Black People, Technocracy, and Legal Process: Thoughts, Fears, and Goals", in Public Policy for the Black Community, ed. by Marguerite Ross Barnett and James A. Hefner (Port Washington, N.Y.: Alfred Publishing, 1976), p, 179.
^ Ball & Gready (2007), p. 35.
^ Littman, David G. (19 January 2003). "Human Rights and Human Wrongs". National Review. Archived from the original on 11 January 2008. Retrieved 7 January 2008. The principal aim of the 1948 Universal Declaration of Human Rights (UDHR) was to create a framework for a universal code based on mutual consent. The early years of the United Nations were overshadowed by the division between the Western and Communist conceptions of human rights, although neither side called into question the concept of universality. The debate centered on which "rights" – political, economic, and social – were to be included among the Universal Instruments
^ Ball & Gready (2007), p. .
^ Ball & Gready (2007), p. 37.
^ "Convention against Torture". OHCHR. 10 December 1984. Archived from the original on 27 March 2013. Retrieved 14 August 2021.
^ "UN declares healthy environment – including clean air – a human right". Climate and Clean Air Coalition. 2 August 2022. Retrieved 21 December 2023.
^ Akbarzadeh, Shahram; Saba, Arif (2020). "UN paralysis over Syria: the responsibility to protect or regime change?". International Politics. 56 (4): 536–550. doi:10.1057/s41311-018-0149-x. S2CID 150004890.
^ Emerson, Michael (1 December 2011). "The responsibility to protect and regime change" (PDF). Centre for European Policy Studies. Archived (PDF) from the original on 6 June 2022. Retrieved 4 May 2022.
^ Habibzadeh, Farrokh (2018). "Economic sanction: a weapon of mass destruction". The Lancet. 392 (10150): 816–817. doi:10.1016/S0140-6736(18)31944-5. PMID 30139528. S2CID 52074513.
^ Mueller, John; Mueller, Karl (1999). "Sanctions of mass destruction". Foreign Affairs. 78 (3): 43–53. doi:10.2307/20049279. JSTOR 20049279.
^ Nesrine Malik (3 July 2018). "Sanctions Against Sudan Didn't Harm an Oppressive Government — They Helped It". Foreign Policy. Archived from the original on 5 May 2022. Retrieved 5 May 2022.
^ Davies, Lizzy (30 April 2022). "Ethiopian drought leading to dramatic increase in child marriage Unicef warns". The Guardian. Archived from the original on 12 May 2022. Retrieved 11 May 2022.
^ "Leveraging education to end female gential mutilation/cutting worldwide" (PDF). International Center for Research on Women. p. 3. Archived (PDF) from the original on 6 October 2022. Retrieved 11 May 2022. For women and girls living in areas where FGM/C is prevalent, they are often dependent upon marriage for financial stability. As a result, FGM/C is seen as a way to guarantee a woman's status, making her able to have children in a socially acceptable way and providing her with economic security, typically provided by the husband. Parents who choose to have their daughters cut consider their decision to be necessary, if not beneficial, for their daughter's future marriage prospects, in light of the financial and social constraints they may face.
^ Ahmed, Beenish (20 January 2014). "Confronting a sexual rite of passage in Malawi". The Atlantic. Archived from the original on 2 December 2019. Retrieved 11 May 2022.
^ "How to stop children working – Focus on reducing poverty and helping parents instead of punishing them". The Economist. 18 September 2021. Archived from the original on 12 May 2022. Retrieved 11 May 2022.
^ "Holocaust Key to Understanding ISIS, Says UN Human Rights Chief". Haaretz. 7 February 2015. Archived from the original on 9 May 2022. Retrieved 8 May 2022.
^ Ball & Gready (2007), p. 92.
^ "Human Rights Council". UN News Centre. Archived from the original on 13 September 2018. Retrieved 14 May 2007.
^ Ball & Gready (2007), p. 95.
^ Shaw (2008), p. 311.
^ "Introduction of the Committee". OHCHR. Archived from the original on 7 March 2022. Retrieved 6 October 2017.
^ Shaw (2008), p. 309.
^ Alston, Philip, ed. (1992). The United Nations and human rights : a critical appraisal. Oxford: Clarendon Press. p. 474. ISBN 978-0198254508.
^ "Cour internationale de Justice – International Court of Justice | International Court of Justice". icj-cij.org. Archived from the original on 2 July 2019. Retrieved 27 August 2019.
^ United Nations. Multilateral treaties deposited with the Secretary-General: Rome Statute of the International Criminal Court Archived 9 May 2008 at the Wayback Machine. Retrieved 8 June 2007.
^ "The Resource Part II: The International Human Rights System". United Nations. Archived from the original on 21 January 2008. Retrieved 31 December 2007.
^ "National Human Right Institutions Forum – An international forum for researchers and practitioners in the field of national human rights". Archived from the original on 15 September 2002. Retrieved 6 September 2007.
^ "Chart of the Status of National Institutions" (PDF). National Human Rights Institutions Forum. November 2007. Archived from the original (PDF) on 16 February 2008. Retrieved 6 January 2008. Accredited by the International Cooordinating Committee of National Institutions for the Promotion of Human Rights In accordance with the Paris Principles and the ICC Sub-Committee Rules of Procedure, the following classifications for accreditation are used by the ICC:A: Compliance with the Paris Principles;A(R): Accreditation with reserve – granted where insufficient documentation is submitted to confer A status;B: Observer Status – Not fully in compliance with the Paris Principles or insufficient information provided to make a determination;C: Non-compliant with the Paris Principles.
^ "HURIDOCS". Archived from the original on 20 April 2019. Retrieved 24 April 2019.
^ "National Human Rights Institutions – Implementing Human Rights", Executive Director Morten Kjærum, The Danish Institute for Human Rights, 2003. ISBN 8790744721, p. 6
^ "AU Member States". African Union. Archived from the original on 5 January 2008. Retrieved 3 January 2008.
^ "AU in a Nutshell". Archived from the original on 30 December 2007. Retrieved 3 January 2008.
^ "Mandate of the African Commission on Human and Peoples' Rights". Archived from the original on 20 January 2008. Retrieved 3 January 2008.
^ "Protocol to the African Charter on Human Rights and Peoples's Rights on the Establishment of an African Court on Human and Peoples' Rights". Archived from the original on 2 March 2012. Retrieved 3 January 2008.
^ "Protocol of the Court of Justice of the African Union" (PDF). African Union. Archived from the original (PDF) on 24 July 2011. Retrieved 4 January 2008.
^ "Open Letter to the Chairman of the African Union (AU) seeking clarifications and assurances that the Establishment of an effective African Court on Human and Peoples' Rights will not be delayed or undermined" (PDF). Amnesty International. 5 August 2004. Archived from the original (PDF) on 18 February 2008. Retrieved 28 January 2019.
^ "African Court of Justice". African International Courts and Tribunals. Archived from the original on 26 July 2013. Retrieved 3 January 2008.
^ "Africa". Human Rights Watch. Archived from the original on 19 July 2019. Retrieved 20 July 2019.
^ "OAS Key Issues". Archived from the original on 3 December 2007. Retrieved 3 January 2008.
^ "Directory of OAS Authorities". Organization of American States. Archived from the original on 20 January 2008. Retrieved 3 January 2008.
^ "What is the IACHR?". Inter-Americal Commission on Human Rights. Archived from the original on 14 January 2008. Retrieved 3 January 2008.
^ "InterAmerican Court on Human Rights homepage". Inter-American Court on Human Rights. Archived from the original on 27 October 2007. Retrieved 3 January 2008.
^ Repucci, Sarah; Slipowitz, Amy (2021). "Democracy Under Siege" (PDF). Freedom in the World. Archived (PDF) from the original on 10 December 2021. Retrieved 27 March 2021. Beijing's export of antidemocratic tactics, financial coercion, and physical intimidation have led to an erosion of democratic institutions and human rights protections in numerous countries...Political rights and civil liberties in the country have deteriorated since Narendra Modi became prime minister in 2014, with increased pressure on human rights organizations, rising intimidation of academics and journalists, and a spate of bigoted attacks, including lynchings, aimed at Muslims.
^ "Democracy Reports | V-Dem". v-dem.net. Archived from the original on 30 June 2021. Retrieved 7 July 2021.
^ "Overview – Association of Southeast Asian Nations". Archived from the original on 11 November 2002. Retrieved 3 January 2008.
^ Bangkok Declaration. Wikisource. Retrieved 14 March 2007
^ "ASEAN Intergovernmental Commission on Human Rights (AICHR)". ASEAN. Archived from the original on 21 April 2021. Retrieved 21 April 2021.
^ "ASEAN Human Rights Declaration (AHRD) and the Phnom Penh Statement on the Adoption of the AHRD and Its Translations" (PDF). ASEAN. 2013. Archived (PDF) from the original on 10 September 2016. Retrieved 21 April 2021.
^ "English Version of the Statute of the Arab Court of Human Rights". acihl.org. ACIHL. Archived from the original on 19 January 2021. Retrieved 14 December 2020.
^ "Council of Europe Human Rights". Council of Europe. Archived from the original on 20 July 2010. Retrieved 4 January 2008.
^ "Social Charter". Council of Europe. Archived from the original on 29 July 2012. Retrieved 4 January 2008.
^ "The Council of Europe in Brief". Archived from the original on 24 November 2003. Retrieved 4 January 2008.
^ Juncker, Jean-Claude (11 April 2006). "Council of Europe – European Union: "A sole ambition for the European Continent"" (PDF). Council of Europe. Archived from the original (PDF) on 1 May 2011. Retrieved 4 January 2008.
^ "Historical Background to the European Court of Human Rights". European Court of Human Rights. Archived from the original on 22 December 2007. Retrieved 4 January 2008.
^ "About the European Committee for the Prevention of Torture". European Committee for the Prevention of Torture. Archived from the original on 2 January 2008. Retrieved 4 January 2008.
^ Shellens (1959).
^ Jaffa (1979).
^ Sills (1968, 1972) Natural Law
^ van Dun, Frank. "Natural Law". Archived from the original on 13 December 2007. Retrieved 28 December 2007.
^ Kohen (2007).
^ Weston, Burns H. "Human Rights". Encyclopedia Britannica Online, p. 2. Archived from the original on 18 December 2007. Retrieved 18 May 2006.
^ Fagan, Andrew (2006). "Human Rights". The Internet Encyclopedia of Philosophy. Archived from the original on 14 April 2009. Retrieved 1 January 2008.
^ Finnis (1980).
^ Nathwani (2003), p. 25.
^ Arnhart (1998).
^ Clayton & Schloss (2004).
^ Paul, Miller, Paul (2001): Arnhart, Larry. Thomistic Natural Law as Darwinian Natural Right p.1
^ Han, Sang-Jin (2020). "A Universal but Non-Hegemonic Approach to Human Rights in International Politics". Confucianism and Reflexive Modernity: Bringing Community back to Human Rights in the Age of Global Risk Society. pp. 102–117. doi:10.1163/9789004415492_008. ISBN 978-9004415492. S2CID 214310918. Retrieved 10 March 2023.
^ 赵汀阳. ""预付人权"：一种非西方的普遍人权理论". 中国社会科学网. Archived from the original on 18 May 2021.
^ Light (2002).
^ Alston (2005), p. 807.
^ Ball & Gready (2007), p. 42.
^ Littman (1999).
^ Ball & Gready (2007), p. 25.
^ Chee, S.J. (3 July 2003). Human Rights: Dirty Words in Singapore. Activating Human Rights and Diversity Conference (Byron Bay, Australia).
^ Tunick (2006).
^ Jahn (2005).
^ Ignatieff (2001), p. 68.
^ Ball & Gready (2007), p. 70.
^ Kissinger, Henry (July–August 2001). "The Pitfall of Universal Jurisdiction". Foreign Affairs. 80 (4): 86–96. doi:10.2307/20050228. JSTOR 20050228. Archived from the original on 14 January 2009. Retrieved 6 January 2008.
^ "Corporations and Human Rights". Human Rights Watch. Archived from the original on 14 November 2008. Retrieved 3 January 2008.
^ "Transnational corporations should be held to human rights standards – UN expert". UN News Centre. 13 October 2003. Archived from the original on 21 January 2008. Retrieved 3 January 2008.
^ "Norms on the responsibilities of transnational corporations and other business enterprises with regard to human rights". UN Sub-Commission on the Promotion and Protection of Human Rights. Archived from the original on 12 September 2016. Retrieved 3 January 2008.
^ "Report on the Economic and Social Council on the Sixtieth Session of the Commission (E/CN.4/2004/L.11/Add.7)" (PDF). United Nations Commission on Human Rights. p. 81. Archived (PDF) from the original on 16 February 2008. Retrieved 3 January 2008.
^ "Goal 10 targets". UNDP. Archived from the original on 27 November 2020. Retrieved 23 September 2020.
^ "The Resource Part II: Human Rights in Times of Emergencies". United Nations. Archived from the original on 21 December 2007. Retrieved 31 December 2007.
^ Shaheed, Ahmed; Richter, Rose Parris (17 October 2018). "Is 'Human Rights' a Western Concept?". IPI Global Observatory. Archived from the original on 10 July 2022. Retrieved 11 August 2022.
^ Silk, James (23 June 2021). "What do we really talk about when we talk about human rights?". OpenGlobalRights. Archived from the original on 11 August 2022. Retrieved 11 August 2022. | biology | 20327 | https://sv.wikipedia.org/wiki/M%C3%A4nskliga%20r%C3%A4ttigheter | Mänskliga rättigheter | De mänskliga rättigheterna är en del av folkrätten och övrig internationell rätt, och preciseras i internationella överenskommelser. Dessa rättigheter reglerar relationen mellan statsmakten och individen och fastställer samtidigt vissa skyldigheter som staten har gentemot individen. De mänskliga rättigheterna har sitt ursprung i den engelska Magna Carta från 1215, den franska Deklarationen om människans och medborgarens rättigheter från 1789 och den amerikanska självständighetsförklaringen från 1776. I Sverige var det Magnus Ladulås lag från 1280 Alsnö stadga som gav frälset sina första rättigheter mot kungens makt. Vissa anger Kyros cylinder som ett tidigt exempel på en uppräkning av några av dagens mänskliga rättigheter.
De mänskliga rättigheterna framställs ofta som universella, bland annat i det engelska namnet på FN:s deklaration om de mänskliga rättigheterna. Det innebär att de gäller över hela jorden, oavsett land, kultur eller andra omständigheter. De gäller för var och en, oavsett etnisk tillhörighet, hudfärg, kön, språk, religion, sexuell läggning, politisk uppfattning eller social ställning. De slår också fast att alla människor är födda fria, är lika i värdighet och har samma rättigheter. Endast de rättigheter som skyddas i den primära folkrätten kan dock upprätthållas i juridisk mening, oavsett viss stats anslutning till berörda internationella överenskommelser.
De mänskliga rättigheterna preciseras alltså i olika internationella överenskommelser. Bland dessa överenskommelser kan man skilja mellan konventioner och protokoll, som blir bindande i.o.m. att staterna uttryckligen förklarar sig bundna av dem, och förklaringar och deklarationer som utgör politiska förpliktelser. Den mest kända deklarationen är FN:s deklaration om de mänskliga rättigheterna från 1948.
Förhistoria
Kyros den stores cylinder räknas som ett av de äldsta dokumenten om mänskliga rättigheter eftersom texten slår vakt om människans rätt till liv, egendom, tankefrihet, religionsfrihet och rätt att bosätta sig var hon vill. Kyros cylinder är dock präglad av sin samtid men kan i vissa avseenden betraktas som en föregångare till vår tids universella rättighetsdeklarationer. Ett väsentligt större inflytande över dagens syn på de mänskliga rättigheter torde det engelska Magna Charta-dokumentet från 1215 ha utövat. I det begränsades kungamaktens krav på suveränitet. Det kom så småningom att utmynna i den i dagens demokratier vedertagna regeln att ingen kung, president eller annat makthavare kan stå över lagen.
Universella konventioner
Efter andra världskriget har olika dokument arbetats fram inom ramen för Förenta Nationernas stadgar som behandlar de mänskliga rättigheterna. De grundläggande internationella konventionerna är
FN:s allmänna deklaration om de mänskliga rättigheterna (1948)
Folkmordskonventionen (1948)
FN:s konvention om avskaffande av alla former av rasdiskriminering (1965)
Konventionen om ekonomiska, sociala och kulturella rättigheter (1966)
FN:s konvention om civila och politiska rättigheter (1966)
Konventionen mot all slags diskriminering av kvinnor (1979)
Konventionen mot tortyr och annan grym, omänsklig eller förnedrande behandling eller bestraffning (1984)
Konventionen om barnets rättigheter (1989)
Konventionen till skydd för alla migrantarbetares och deras familjers rättigheter (1990)
FN:s deklaration om människorättsförsvarare (1998)
Konventionen om rättigheter för personer med funktionsnedsättning (2006)
Konventionen till skydd för alla människor mot påtvingade försvinnanden (2006)
Texten till deklarationen om de mänskliga rättigheterna skrevs av FN:s kommission för de mänskliga rättigheterna, med Eleanor Roosevelt som ordförande. Den 10 december 1948 antogs den av generalförsamlingen med 48 röster för, 0 emot, och 8 blanka, däribland Sydafrika, Sovjetunionen och övriga länder i östblocket.
Internationella konventioner
Den europeiska konventionen angående skydd för de mänskliga rättigheterna och de grundläggande friheterna (1950)
Den amerikanska konventionen om mänskliga rättigheter, (1969)
Afrikanska stadgan om mänskliga och folkens rättigheter, (1981)
Kairodeklarationen om de mänskliga rättigheterna i islam (1990; aldrig officiellt antagen)
Arabiska stadgan om de mänskliga rättigheterna (1994; trädde i kraft maj 2008)
Europeiska unionens stadga om de grundläggande rättigheterna, (2000)
Kategorisering av de mänskliga rättigheterna
Under Världskonferensen i Teheran 1968 fastslogs att de mänskliga rättigheterna och friheterna är odelbara och avhängiga varandra. Olika stater har emellertid sedan de ratificerat dem uttryckt kritik för att de ekonomiska, sociala och kulturella rättigheterna utvecklats till ambitioner snarare än grundläggande, universella rättigheter.
1941 formulerade president Roosevelt fyra friheter (The Four Freedoms) som var hans vision om världen efter andra världskriget: frihet att tala och uttrycka sig över hela världen, frihet att tillbedja Gud på sitt eget sätt över hela världen, frihet från armod (want) och frihet från rädsla. I synnerhet de två sista friheterna brukar framhållas som beskrivning av de mänskliga rättigheterna, då de anses inbegripa de två förra.
Olika kategoriseringar kan göras av de mänskliga rättigheterna, men detta görs alltid utan att dessa rättigheter graderas inbördes: Rättigheterna gäller varje individs rätt till ett drägligt liv, rätt till sina innersta tankar, skydd för familjen, frihet från tortyr och slaveri, rätt till utbildning och rätt till yttrandefrihet och deltagande i landets styre.
Emellertid preciseras de mänskliga rättigheterna i detalj av en lång rad dokument. För att få en överblick över dessa kan till exempel följande kategorier av rättigheter urskiljas:
Medborgerliga och politiska rättigheter
Ekonomiska, sociala och kulturella rättigheter
Skydd mot diskriminering
Nationella minoriteter och urbefolkningar
Likhet inför lagen
Barnets rättigheter
Kvinnors rättigheter - kvinnlig rösträtt
Rättigheter för personer med funktionsnedsättning
Rättigheter för HBTQ-personer (Yogyakartaprinciperna)
Asylfrågor
Övriga frågor
Skillnader mellan olika deklarationer och konventioner
Trots att de mänskliga rättigheterna är universella, har dess konventioner formulerats olika, varför det ibland uppstått konflikter i tolkningen. Europakonventionen och den amerikanska konventionen om de mänskliga rättigheterna, utgår huvudsakligen från individens rätt, och har sin idéhistoriska upprinnelse i humanismen, den västerländska debatten om naturrätten och upplysningens idédebatt. Vad beträffar den afrikanska stadgan om de mänskliga rättigheterna, och även generellt i u-länder och i stater utan parlamentariskt demokratiska system, däribland Kina, har de mänskliga rättigheterna delvis kollektiva formuleringar, och betonar även folkets rätt till utveckling, men också individers skyldigheter.
Under världskonferensen i Wien 1993 uppenbarades tolkningsolikheterna även så tillvida att bland annat Kina och Pakistan menade att de mänskliga rättigheterna är varje stats angelägenhet, och att FN inte har rätt att kontrollera att staterna efterlever dem. I samband med detta enades konferensen om en deklaration som slog fast att världssamfundet har en universell kontrollfunktion och ska se till att de mänskliga rättigheterna efterlevs. För detta instiftades samma år en högkommissarie för mänskliga rättigheter. Högkommissarien är placerad i Genève och är tillika chef för centret för de mänskliga rättigheterna.
FN:s deklaration om de mänskliga rättigheterna kan betraktas som internationell lag genom rättspraxis (international costumary law), även om den inte till formen är juridiskt bindande.
EU, Europakonventionen och mänskliga rättigheter
I EU har Mänskliga rättigheter en central plats genom Europakonventionen. Stater som vill söka medlemskap i EU möter krav på att uppfylla grundläggande mänskliga rättigheter. EU ställer även krav på omvärlden. EU har också utarbetat särskilda riktlinjer för att främja de mänskliga rättigheterna genom sina relationer med tredje land. Det gäller bland annat riktlinjer om dödsstraff och tortyr samt barns och kvinnors rättigheter.
Europadomstolen och Europeiska unionens domstol är de primära och huvudsakliga utövarna av juridiska mänskliga rättigheter i Sverige samt har tolkningsföreträde i alla avseenden som berör mänskliga rättigheter och EU-rätt.
FN
FN:s råd för mänskliga rättigheter och andra speciella ändemål
Beslutet att etablera FN:s råd för mänskliga rättigheter skedde vid Världstoppmötet 2005, och rådet grundades formellt av FN:s generalförsamling den 15 mars 2006. Rådet har mandat att undersöka brott mot mänskliga rättigheter samt framföra rekommendationer om dessa. Rådet är ett underorgan till generalförsamlingen.
Se även
Människovärde
Människorättsförsvarare
Mänskliga rättigheter inom islam
Brott mot mänskligheten
Kyros cylinder
Jus cogens
Referenser
FN - Globalt uppdrag, huvudred. Lars Eriksson (Sthlm 1995)
Understanding Human rights. Manual om human rights education, Human Security Network, European Training and Research Centre for Human Rights and Democracy, ed. Wolfgang Benedek och Minna Nikolova (ETC) (Graz 2003)
Danelius, Hans, Mänskliga rättigheter (Sthlm 1993)
Bring, Ove, De mänskliga rättigheternas väg - genom historien och litteraturen, Atlantis 2011
Externa länkar
Allmän förklaring om de mänskliga rättigheterna på Förenta nationernas webbplats
Fakta om mänskliga rättigheter på Sveriges regerings webbplats
Wikipedia:Basartiklar
Rättsekonomi | swedish | 0.518272 |
humans_closest_relatives_after_primates/Colugo.txt |
Colugos (/kəˈluːɡoʊ/) are arboreal gliding mammals that are native to Southeast Asia. Their closest evolutionary relatives are primates. There are just two living species of colugos: the Sunda flying lemur (Galeopterus variegatus) and the Philippine flying lemur (Cynocephalus volans). These two species make up the entire family Cynocephalidae (/ˌsaɪnoʊˌsɛfəˈlaɪdi, -ˌkɛ-/) and order Dermoptera (not to be confused with Dermaptera, an order of insects known as earwigs).
Characteristics[edit]
Colugos are nocturnal, tree-dwelling mammals.
Appearance and anatomy[edit]
They reach lengths of 35 to 40 cm (14 to 16 in) and weigh 1 to 2 kg (2.2 to 4.4 lb). They have long, slender front and rear limbs, a medium-length tail, and a relatively light build. The head is small, with large, front-focused eyes for excellent binocular vision, and small rounded ears.
The incisor teeth of colugos are highly distinctive; they are comb-like in shape with up to 20 tines on each tooth. The incisors are analogous in appearance and function to the incisor suite in strepsirrhines, which is used for grooming. The second upper incisors have two roots, another unique feature among mammals. The dental formula of colugos is: 2.1.2.33.1.2.3
Feet of Philippine colugo.
Movement[edit]
Colugos are proficient gliders, and they can travel as far as 70 m (230 ft) from one tree to another without losing much altitude, with a Malayan colugo (Galeopterus variegatus) individual having travelled about 150 m (490 ft) in one glide.
Of all the gliding mammals, colugos have the most perfected adaptation for flight. They have a large membrane of skin that extends between their paired limbs and gives them the ability to glide significant distances between trees. This gliding membrane, or patagium, runs from the shoulder blades to the fore paws, from the tip of the rear-most fingers to the tip of the toes, and from the hind legs to the tip of the tail. The spaces between the colugo's fingers and toes are webbed. As a result, colugos were once considered to be close relatives of bats. Today, on account of genetic data, they are considered to be more closely related to primates.
Lower jaw (Galeopterus).
Colugos are unskilled climbers; they lack opposable thumbs. They progress up trees in a series of slow hops, gripping onto the bark with their small, sharp claws. They spend most of the day resting. At night, colugos spend most of their time up in the trees foraging, with gliding being used to either find another foraging tree or to find possible mates and protect territory.
Behavior and diet[edit]
Colugos are shy, nocturnal, solitary animals found in the tropical forests of Southeast Asia. Consequently, very little is known about their behavior. They are herbivorous and eat leaves, shoots, flowers, sap, and fruit. They have well-developed stomachs and long intestines capable of extracting nutrients from leaves and other fibrous material.
Colugos have evolved into a nocturnal species, along with the ability to proficiently see during the nighttime. Colugos spend their days resting in tree holes and are active at night time; traveling around 1.7 km at night. Colugos may also be a territorial species.
Life cycle[edit]
Although they are placental mammals, colugos raise their young in a manner similar to marsupials. Newborn colugos are underdeveloped and weigh only 35 g (1.2 oz). They spend the first six months of life clinging to their mother's belly. The mother colugo curls her tail and folds her patagium into a warm, secure, quasipouch to protect and transport her young. The young do not reach maturity until they are two to three years old. In captivity, they live up to 15 years, but their lifespan in the wild is unknown.
Status[edit]
Both species are threatened by habitat destruction, and the Philippine flying lemur was once classified by the IUCN as vulnerable. In 1996, the IUCN declared the species vulnerable owing to destruction of lowland forests and hunting. It was downlisted to least-concern status in 2008 but still faces the same threats. In addition to the ongoing clearing of its rainforest habitat, it is hunted for its meat and fur. It is also a favorite prey item for the critically endangered Philippine eagle; some studies suggest colugos account for 90% of the eagle's diet.
Taxonomy[edit]
Their family name Cynocephalidae comes from the Greek words κύων kyōn "dog" and κεφαλή kephalē "head" because their heads are broad with short snouts like dogs.
Classification and evolution[edit]
Order Dermoptera
†Family Plagiomenidae?
†Planetetherium
†Planetetherium mirabile
†Plagiomene
†Plagiomene multicuspis
†Family Mixodectidae?
†Dracontolestes
†Dracontolestes aphantus
†Eudaemonema
†Eudaemonema cuspidata
†Mixodectes
†Mixodectes pungens
†Mixodectes malaris
Family Cynocephalidae
Cynocephalus
Philippine flying lemur, Cynocephalus volans
Galeopterus
Sunda flying lemur, Galeopterus variegatus
†Dermotherium
†Dermotherium major
†Dermotherium chimaera
The Mixodectidae and Plagiomenidae appear to be fossil Dermoptera. Although other Paleogene mammals have been interpreted as related to dermopterans, the evidence for this association is uncertain and many of the fossils are no longer interpreted as being gliding mammals. At present, the fossil record of definitive dermopterans is limited to two species of the Eocene and Oligocene cynocephalid genus Dermotherium.
Molecular phylogenetic studies have demonstrated that colugos emerged as a basal Primatomorpha clade – which, in turn, is a basal Euarchontoglires clade. Scandentia are widely considered to be the closest relatives of Primatomorpha, within Euarchonta. Some studies, however, place Scandentia as sister of Glires (lagomorphs and rodents), in an unnamed sister clade of the Primatomorpha.
Euarchontoglires
Scandentia (treeshrews)
Glires
Lagomorpha (rabbits, hares, pikas)
Rodentia (rodents)
Primatomorpha
Dermoptera (colugos)
†Plesiadapiformes
Primates
Gallery[edit]
Claw of Sunda flying lemur. | biology | 4374183 | https://sv.wikipedia.org/wiki/Acantholimon%20speciosissimum | Acantholimon speciosissimum | Acantholimon speciosissimum är en triftväxtart som beskrevs av James Edward Tierney Aitchison och William Botting Hemsley. Acantholimon speciosissimum ingår i släktet Acantholimon och familjen triftväxter. Inga underarter finns listade i Catalogue of Life.
Källor
Triftväxter
speciosissimum | swedish | 0.76906 |
humans_closest_relatives_after_primates/Primate.txt |
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes). Primates arose 85–55 million years ago first from small terrestrial mammals, which adapted to living in the trees of tropical forests: many primate characteristics represent adaptations to life in this challenging environment, including large brains, visual acuity, color vision, a shoulder girdle allowing a large degree of movement in the shoulder joint, and dexterous hands. Primates range in size from Madame Berthe's mouse lemur, which weighs 30 g (1 oz), to the eastern gorilla, weighing over 200 kg (440 lb). There are 376–524 species of living primates, depending on which classification is used. New primate species continue to be discovered: over 25 species were described in the 2000s, 36 in the 2010s, and six in the 2020s.
Primates have large brains (relative to body size) compared to other mammals, as well as an increased reliance on visual acuity at the expense of the sense of smell, which is the dominant sensory system in most mammals. These features are more developed in monkeys and apes, and noticeably less so in lorises and lemurs. Most primates also have opposable thumbs. Some primates, including gorillas, humans, and baboons, are primarily terrestrial rather than arboreal, but all species have adaptations for climbing trees. Arboreal locomotion techniques used include leaping from tree to tree and swinging between branches of trees (brachiation); terrestrial locomotion techniques include walking on two limbs (bipedalism) and modified walking on four limbs (knuckle-walking).
Primates are among the most social of animals, forming pairs or family groups, uni-male harems, and multi-male/multi-female groups. Non-human primates have at least four types of social systems, many defined by the amount of movement by adolescent females between groups. Primates have slower rates of development than other similarly sized mammals, reach maturity later, and have longer lifespans. Primates are also the most intelligent animals and non-human primates are recorded to use tools. They may communicate using facial and hand gestures, smells and vocalizations.
Close interactions between humans and non-human primates (NHPs) can create opportunities for the transmission of zoonotic diseases, especially virus diseases, including herpes, measles, ebola, rabies, and hepatitis. Thousands of non-human primates are used in research around the world because of their psychological and physiological similarity to humans. About 60% of primate species are threatened with extinction. Common threats include deforestation, forest fragmentation, monkey drives, and primate hunting for use in medicines, as pets, and for food. Large-scale tropical forest clearing for agriculture most threatens primates.
Etymology[edit]
The English name primates is derived from Old French or French primat, from a noun use of Latin primat-, from primus ('prime, first rank'). The name was given by Carl Linnaeus because he thought this the "highest" order of animals. The relationships among the different groups of primates were not clearly understood until relatively recently, so the commonly used terms are somewhat confused. For example, ape has been used either as an alternative for monkey or for any tailless, relatively human-like primate.
Sir Wilfrid Le Gros Clark was one of the primatologists who developed the idea of trends in primate evolution and the methodology of arranging the living members of an order into an "ascending series" leading to humans. Commonly used names for groups of primates such as prosimians, monkeys, lesser apes, and great apes reflect this methodology. According to our current understanding of the evolutionary history of the primates, several of these groups are paraphyletic, or rather they do not include all the descendants of a common ancestor.
In contrast with Clark's methodology, modern classifications typically identify (or name) only those groupings that are monophyletic; that is, such a named group includes all the descendants of the group's common ancestor.
The cladogram below shows one possible classification sequence of the living primates: groups that use common (traditional) names are shown on the right.
Primatomorpha
Dermoptera
Primates
Strepsirrhini
Lemuriformes
lemurs (superfamily Lemuroidea)
lorises and allies (superfamily Lorisoidea)
Haplorhini
Tarsiiformes
tarsiers (superfamily Tarsioidea)
Simiiformes
New World monkeys (parvorder Platyrrhini)
Catarrhini
Old World monkeys (superfamily Cercopithecoidea)
Hominoidea
gibbons (family Hylobatidae)
Hominidae
orangutans (subfamily Ponginae)
Homininae
gorillas (tribe Gorillini)
Hominini
chimpanzees, bonobos (g. Pan)
humans (g. Homo)
prosimians
monkeys
lesser apes
great apes
All groups with scientific names are clades, or monophyletic groups, and the sequence of scientific classification reflects the evolutionary history of the related lineages. Groups that are traditionally named are shown on the right; they form an "ascending series" (per Clark, see above), and several groups are paraphyletic:
Prosimians contain two monophyletic groups (the suborder Strepsirrhini, or lemurs, lorises and allies, as well as the tarsiers of the suborder Haplorhini); it is a paraphyletic grouping because it excludes the Simiiformes, which also are descendants of the common ancestor Primates.
Monkeys comprise two monophyletic groups, New World monkeys and Old World monkeys, but is paraphyletic because it excludes hominoids, superfamily Hominoidea, also descendants of the common ancestor Simiiformes.
Apes as a whole, and the great apes, are paraphyletic if the terms are used such that they exclude humans.
Thus, the members of the two sets of groups, and hence names, do not match, which causes problems in relating scientific names to common (usually traditional) names. Consider the superfamily Hominoidea: In terms of the common names on the right, this group consists of apes and humans and there is no single common name for all the members of the group. One remedy is to create a new common name, in this case hominoids. Another possibility is to expand the use of one of the traditional names. For example, in his 2005 book, the vertebrate palaeontologist Benton wrote, "The apes, Hominoidea, today include the gibbons and orangutan ... the gorilla and chimpanzee ... and humans"; thereby Benton was using apes to mean hominoids. In that case, the group heretofore called apes must now be identified as the non-human apes.
As of 2021, there is no consensus as to whether to accept traditional (that is, common), but paraphyletic, names or to use monophyletic names only; or to use 'new' common names or adaptations of old ones. Both competing approaches can be found in biological sources, often in the same work, and sometimes by the same author. Thus, Benton defines apes to include humans, then he repeatedly uses ape-like to mean 'like an ape rather than a human'; and when discussing the reaction of others to a new fossil he writes of "claims that Orrorin ... was an ape rather than a human".
Classification of living primates[edit]
A 1927 drawing of chimpanzees, a gibbon (top right) and two orangutans (center and bottom center): The chimpanzee in the upper left is brachiating; the orangutan at the bottom center is knuckle-walking.
Homo sapiens is the only living primate species that is fully bipedal
Nilgiri langur (Trachypithecus johnii), an Old World monkey
A list of the families of the living primates is given below, together with one possible classification into ranks between order and family. Other classifications are also used. For example, an alternative classification of the living Strepsirrhini divides them into two infraorders, Lemuriformes and Lorisiformes.
Order Primates
Suborder Strepsirrhini: lemurs, galagos and lorisids
Infraorder Lemuriformes
Superfamily Lemuroidea
Family Cheirogaleidae: dwarf lemurs and mouse-lemurs (41 species)
Family Daubentoniidae: aye-aye (1 species)
Family Lemuridae: ring-tailed lemur and allies (21 species)
Family Lepilemuridae: sportive lemurs (26 species)
Family Indriidae: woolly lemurs and allies (19 species)
Superfamily Lorisoidea
Family Lorisidae: lorisids (16 species)
Family Galagidae: galagos (23 species)
Suborder Haplorhini: tarsiers, monkeys and apes
Infraorder Tarsiiformes
Family Tarsiidae: tarsiers (14 species)
Infraorder Simiiformes (or Anthropoidea)
Parvorder Platyrrhini: New World monkeys
Family Callitrichidae: marmosets and tamarins (49 species)
Family Cebidae: capuchins and squirrel monkeys (29 species)
Family Aotidae: night or owl monkeys (douroucoulis) (11 species)
Family Pitheciidae: titis, sakis and uakaris (56 species)
Family Atelidae: howler, spider, woolly spider and woolly monkeys (26 species)
Parvorder Catarrhini
Superfamily Cercopithecoidea
Family Cercopithecidae: Old World monkeys (165 species)
Superfamily Hominoidea
Family Hylobatidae: gibbons or "lesser apes" (20 species)
Family Hominidae: great apes, including humans (8 species)
Order Primates was established by Carl Linnaeus in 1758, in the tenth edition of his book Systema Naturae, for the genera Homo (humans), Simia (other apes and monkeys), Lemur (prosimians) and Vespertilio (bats). In the first edition of the same book (1735), he had used the name Anthropomorpha for Homo, Simia and Bradypus (sloths). In 1839, Henri Marie Ducrotay de Blainville, following Linnaeus and imitating his nomenclature, established the orders Secundates (including the suborders Chiroptera, Insectivora and Carnivora), Tertiates (or Glires) and Quaternates (including Gravigrada, Pachydermata and Ruminantia), but these new taxa were not accepted.
Before Anderson and Jones introduced the classification of Strepsirrhini and Haplorhini in 1984, (followed by McKenna and Bell's 1997 work Classification of Mammals: Above the species level), Primates was divided into two superfamilies: Prosimii and Anthropoidea. Prosimii included all of the prosimians: Strepsirrhini plus the tarsiers. Anthropoidea contained all of the simians.
Phylogeny and genetics[edit]
Euarchontoglires
Glires
Rodentia (rodents)
Lagomorpha (rabbits, hares, pikas)
Euarchonta
Scandentia (treeshrews)
Primatomorpha
Dermoptera (colugos)
Primates
†Plesiadapiformes
crown primates
Order Primates is part of the clade Euarchontoglires, which is nested within the clade Eutheria of Class Mammalia. Recent molecular genetic research on primates, colugos, and treeshrews has shown that the two species of colugos are more closely related to primates than to treeshrews, even though treeshrews were at one time considered primates. These three orders make up the clade Euarchonta. The combination of this clade with the clade Glires (composed of Rodentia and Lagomorpha) forms the clade Euarchontoglires. Variously, both Euarchonta and Euarchontoglires are ranked as superorders. Some scientists consider Dermoptera to be a suborder of Primates and use the suborder Euprimates for the "true" primates.
Evolutionary history[edit]
Further information: Evolution of primates
The primate lineage is thought to go back at least near the Cretaceous–Paleogene boundary or around 63–74 (mya). The earliest possible primate/proto-primate may be Purgatorius, which dates back to Early Paleocene of North America ~66mya. The oldest known primates from the fossil record date to the Late Paleocene of Africa, c.57 mya (Altiatlasius) or the Paleocene-Eocene transition in the northern continents, c. 55 mya (Cantius, Donrussellia, Altanius, Plesiadapis and Teilhardina). Other studies, including molecular clock studies, have estimated the origin of the primate branch to have been in the mid-Cretaceous period, around 85 mya.
By modern cladistic reckoning, the order Primates is monophyletic. The suborder Strepsirrhini, the "wet-nosed" primates, is generally thought to have split off from the primitive primate line about 63 mya, although earlier dates are also supported. The seven strepsirrhine families are the five related lemur families and the two remaining families that include the lorisids and the galagos. Older classification schemes wrap Lepilemuridae into Lemuridae and Galagidae into Lorisidae, yielding a four-one family distribution instead of five-two as presented here. During the Eocene, most of the northern continents were dominated by two groups, the adapiforms and the omomyids. The former are considered members of Strepsirrhini, but did not have a toothcomb like modern lemurs; recent analysis has demonstrated that Darwinius masillae fits into this grouping. The latter was closely related to tarsiers, monkeys, and apes. How these two groups relate to extant primates is unclear. Omomyids perished about 30 mya, while adapiforms survived until about 10 mya.
According to genetic studies, the lemurs of Madagascar diverged from the lorisoids approximately 75 mya. These studies, as well as chromosomal and molecular evidence, also show that lemurs are more closely related to each other than to other strepsirrhine primates. However, Madagascar split from Africa 160 mya and from India 90 mya. To account for these facts, a founding lemur population of a few individuals is thought to have reached Madagascar from Africa via a single rafting event between 50 and 80 mya. Other colonization options have been suggested, such as multiple colonizations from Africa and India, but none are supported by the genetic and molecular evidence.
Common brown lemur, a Strepsirrhine primate
Until recently, the aye-aye has been difficult to place within Strepsirrhini. Theories had been proposed that its family, Daubentoniidae, was either a lemuriform primate (meaning its ancestors split from the lemur line more recently than lemurs and lorises split) or a sister group to all the other strepsirrhines. In 2008, the aye-aye family was confirmed to be most closely related to the other Malagasy lemurs, likely having descended from the same ancestral population that colonized the island.
Suborder Haplorhini, the simple-nosed or "dry-nosed" primates, is composed of two sister clades. Prosimian tarsiers in the family Tarsiidae (monotypic in its own infraorder Tarsiiformes), represent the most basal division, originating about 58 mya. The earliest known haplorhine skeleton, that of 55 MA old tarsier-like Archicebus, was found in central China, supporting an already suspected Asian origin for the group. The infraorder Simiiformes (simian primates, consisting of monkeys and apes) emerged about 40 mya, possibly also in Asia; if so, they dispersed across the Tethys Sea from Asia to Africa soon afterwards. There are two simian clades, both parvorders: Catarrhini, which developed in Africa, consisting of Old World monkeys, humans and the other apes, and Platyrrhini, which developed in South America, consisting of New World monkeys. A third clade, which included the eosimiids, developed in Asia, but became extinct millions of years ago.
As in the case of lemurs, the origin of New World monkeys is unclear. Molecular studies of concatenated nuclear sequences have yielded a widely varying estimated date of divergence between platyrrhines and catarrhines, ranging from 33 to 70 mya, while studies based on mitochondrial sequences produce a narrower range of 35 to 43 mya. The anthropoid primates possibly traversed the Atlantic Ocean from Africa to South America during the Eocene by island hopping, facilitated by Atlantic Ocean ridges and a lowered sea level. Alternatively, a single rafting event may explain this transoceanic colonization. Due to continental drift, the Atlantic Ocean was not nearly as wide at the time as it is today. Research suggests that a small 1 kg (2.2 lb) primate could have survived 13 days on a raft of vegetation. Given estimated current and wind speeds, this would have provided enough time to make the voyage between the continents.
Emperor tamarin, a New World monkey
Apes and monkeys spread from Africa into Europe and Asia starting in the Miocene. Soon after, the lorises and tarsiers made the same journey. The first hominin fossils were discovered in northern Africa and date back 5–8 mya. Old World monkeys disappeared from Europe about 1.8 mya. Molecular and fossil studies generally show that modern humans originated in Africa 100,000–200,000 years ago.
Although primates are well studied in comparison to other animal groups, several new species have been discovered recently, and genetic tests have revealed previously unrecognised species in known populations. Primate Taxonomy listed about 350 species of primates in 2001; the author, Colin Groves, increased that number to 376 for his contribution to the third edition of Mammal Species of the World (MSW3). However, publications since the taxonomy in MSW3 was compiled in 2003 have pushed the number to 522 species, or 708 including subspecies.
Hybrids[edit]
Primate hybrids usually arise in captivity, but there have also been examples in the wild. Hybridization occurs where two species' range overlap to form hybrid zones; hybrids may be created by humans when animals are placed in zoos or due to environmental pressures such as predation. Intergeneric hybridizations, hybrids of different genera, have also been found in the wild. Although they belong to genera that have been distinct for several million years, interbreeding still occurs between the gelada and the hamadryas baboon.
Clones[edit]
On 24 January 2018, scientists in China reported in the journal Cell the creation of two crab-eating macaque clones, named Zhong Zhong and Hua Hua, using the complex DNA transfer method that produced Dolly the sheep, for the first time.
Anatomy and physiology[edit]
Head[edit]
Primate skulls showing postorbital bar, and increasing brain sizes
The primate skull has a large, domed cranium, which is particularly prominent in anthropoids. The cranium protects the large brain, a distinguishing characteristic of this group. The endocranial volume (the volume within the skull) is three times greater in humans than in the greatest nonhuman primate, reflecting a larger brain size. The mean endocranial volume is 1,201 cubic centimeters in humans, 469 cm in gorillas, 400 cm in chimpanzees and 397 cm in orangutans. The primary evolutionary trend of primates has been the elaboration of the brain, in particular the neocortex (a part of the cerebral cortex), which is involved with sensory perception, generation of motor commands, spatial reasoning, conscious thought and, in humans, language. While other mammals rely heavily on their sense of smell, the arboreal life of primates has led to a tactile, visually dominant sensory system, a reduction in the olfactory region of the brain and increasingly complex social behavior. The visual acuity of humans and other hominids is exceptional; they have the most acute vision known among all vertebrates, with the exception of certain species of predatory birds.
Primates have forward-facing eyes on the front of the skull; binocular vision allows accurate distance perception, useful for the brachiating ancestors of all great apes. A bony ridge above the eye sockets reinforces weaker bones in the face, which are put under strain during chewing. Strepsirrhines have a postorbital bar, a bone around the eye socket, to protect their eyes; in contrast, the higher primates, haplorhines, have evolved fully enclosed sockets.
An 1893 drawing of the hands and feet of various primates
Primates show an evolutionary trend towards a reduced snout. Technically, Old World monkeys are distinguished from New World monkeys by the structure of the nose, and from apes by the arrangement of their teeth. In New World monkeys, the nostrils face sideways; in Old World monkeys, they face downwards. Dental pattern in primates vary considerably; although some have lost most of their incisors, all retain at least one lower incisor. In most strepsirrhines, the lower incisors form a toothcomb, which is used in grooming and sometimes foraging. Old World monkeys have eight premolars, compared with 12 in New World monkeys. The Old World species are divided into apes and monkeys depending on the number of cusps on their molars: monkeys have four, apes have five - although humans may have four or five. The main hominid molar cusp (hypocone) evolved in early primate history, while the cusp of the corresponding primitive lower molar (paraconid) was lost. Prosimians are distinguished by their immobilized upper lips, the moist tip of their noses and forward-facing lower front teeth.
Body[edit]
Vervet hindfoot showing fingerprint ridges on the sole
Primates generally have five digits on each limb (pentadactyly), with a characteristic type of keratin fingernail on the end of each finger and toe. The bottom sides of the hands and feet have sensitive pads on the fingertips. Most have opposable thumbs, a characteristic primate feature most developed in humans, though not limited to this order (opossums and koalas, for example, also have them). Thumbs allow some species to use tools. In primates, the combination of opposing thumbs, short fingernails (rather than claws) and long, inward-closing fingers is a relict of the ancestral practice of gripping branches, and has, in part, allowed some species to develop brachiation (swinging by the arms from tree limb to tree limb) as a significant means of locomotion. Prosimians have clawlike nails on the second toe of each foot, called toilet-claws, which they use for grooming.
The primate collar bone is a prominent element of the pectoral girdle; this allows the shoulder joint broad mobility. Compared to Old World monkeys, apes have more mobile shoulder joints and arms due to the dorsal position of the scapula, broad ribcages that are flatter front-to-back, a shorter, less mobile spine, and with lower vertebrae greatly reduced - resulting in tail loss in some species. Prehensile tails are found in the New World atelids, including the howler, spider, woolly spider, woolly monkeys; and in capuchins. Male primates have a low-hanging penis and testes descended into a scrotum.
Sexual dimorphism[edit]
Main article: Sexual dimorphism in non-human primates
Distinct sexual size dimorphism can be seen between the male and female mountain gorilla.
Sexual dimorphism is often exhibited in simians, though to a greater degree in Old World species (apes and some monkeys) than New World species. Recent studies involve comparing DNA to examine both the variation in the expression of the dimorphism among primates and the fundamental causes of sexual dimorphism. Primates usually have dimorphism in body mass and canine tooth size along with pelage and skin color. The dimorphism can be attributed to and affected by different factors, including mating system, size, habitat and diet.
Comparative analyses have generated a more complete understanding of the relationship between sexual selection, natural selection, and mating systems in primates. Studies have shown that dimorphism is the product of changes in both male and female traits. Ontogenetic scaling, where relative extension of a common growth trajectory occurs, may give some insight into the relationship between sexual dimorphism and growth patterns. Some evidence from the fossil record suggests that there was convergent evolution of dimorphism, and some extinct hominids probably had greater dimorphism than any living primate.
Locomotion[edit]
Diademed sifaka, a lemur that is a vertical clinger and leaper
Primate species move by brachiation, bipedalism, leaping, arboreal and terrestrial quadrupedalism, climbing, knuckle-walking or by a combination of these methods. Several prosimians are primarily vertical clingers and leapers. These include many bushbabies, all indriids (i.e., sifakas, avahis and indris), sportive lemurs, and all tarsiers. Other prosimians are arboreal quadrupeds and climbers. Some are also terrestrial quadrupeds, while some are leapers. Most monkeys are both arboreal and terrestrial quadrupeds and climbers. Gibbons, muriquis and spider monkeys all brachiate extensively, with gibbons sometimes doing so in remarkably acrobatic fashion. Woolly monkeys also brachiate at times. Orangutans use a similar form of locomotion called quadramanous climbing, in which they use their arms and legs to carry their heavy bodies through the trees. Chimpanzees and gorillas knuckle walk, and can move bipedally for short distances. Although numerous species, such as australopithecines and early hominids, have exhibited fully bipedal locomotion, humans are the only extant species with this trait.
Vision[edit]
The tapetum lucidum of a northern greater galago, typical of prosimians, reflects the light of the photographer's flash.
The evolution of color vision in primates is unique among most eutherian mammals. While the remote vertebrate ancestors of the primates possessed three color vision (trichromaticism), the nocturnal, warm-blooded, mammalian ancestors lost one of three cones in the retina during the Mesozoic era. Fish, reptiles and birds are therefore trichromatic or tetrachromatic, while all mammals, with the exception of some primates and marsupials, are dichromats or monochromats (totally color blind). Nocturnal primates, such as the night monkeys and bush babies, are often monochromatic. Catarrhines are routinely trichromatic due to a gene duplication of the red-green opsin gene at the base of their lineage, 30 to 40 million years ago. Platyrrhines, on the other hand, are trichromatic in a few cases only. Specifically, individual females must be heterozygous for two alleles of the opsin gene (red and green) located on the same locus of the X chromosome. Males, therefore, can only be dichromatic, while females can be either dichromatic or trichromatic. Color vision in strepsirrhines is not as well understood; however, research indicates a range of color vision similar to that found in platyrrhines.
Like catarrhines, howler monkeys (a family of platyrrhines) show routine trichromatism that has been traced to an evolutionarily recent gene duplication. Howler monkeys are one of the most specialized leaf-eaters of the New World monkeys; fruits are not a major part of their diets, and the type of leaves they prefer to consume (young, nutritive, and digestible) are detectable only by a red-green signal. Field work exploring the dietary preferences of howler monkeys suggests that routine trichromaticism was selected by environment.
Behavior[edit]
Social systems[edit]
Richard Wrangham stated that social systems of primates are best classified by the amount of movement by females occurring between groups. He proposed four categories:
Female transfer systems – females move away from the group in which they were born. Females of a group will not be closely related whereas males will have remained with their natal groups, and this close association may be influential in social behavior. The groups formed are generally quite small. This organization can be seen in chimpanzees, where the males, who are typically related, will cooperate in defense of the group's territory. Evidence of this social system has also been found among Neanderthal remains in Spain and in remains of Australopithecus and Paranthropus robustus groups in southern Africa. Among New World Monkeys, spider monkeys and muriquis use this system.
A social huddle of ring-tailed lemurs. The two individuals on the right exposing their white ventral surface are sunning themselves.
Male transfer systems – while the females remain in their natal groups, the males will emigrate as adolescents. Polygynous and multi-male societies are classed in this category. Group sizes are usually larger. This system is common among the ring-tailed lemur, capuchin monkeys and cercopithecine monkeys.
Monogamous species – a male–female bond, sometimes accompanied by a juvenile offspring. There is shared responsibility of parental care and territorial defense. The offspring leaves the parents' territory during adolescence. Gibbons essentially use this system, although "monogamy" in this context does not necessarily mean absolute sexual fidelity. These species do not live in larger groups.
Solitary species – often males who defend territories that include the home ranges of several females. This type of organization is found in the prosimians such as the slow loris. Orangutans do not defend their territory but effectively have this organization.
Other systems are known to occur as well. For example, with howler monkeys and gorillas both the males and females typically transfer from their natal group on reaching sexual maturity, resulting in groups in which neither the males nor females are typically related. Some prosimians, colobine monkeys and callitrichid monkeys also use this system.
The transfer of females or males from their native group is likely an adaptation for avoiding inbreeding. An analysis of breeding records of captive primate colonies representing numerous different species indicates that the infant mortality of inbred young is generally higher than that of non-inbred young. This effect of inbreeding on infant mortality is probably largely a result of increased expression of deleterious recessive alleles (see Inbreeding depression).
Chimpanzees are social great apes.
Primatologist Jane Goodall, who studied in the Gombe Stream National Park, noted fission-fusion societies in chimpanzees. There is fission when the main group splits up to forage during the day, then fusion when the group returns at night to sleep as a group. This social structure can also be observed in the hamadryas baboon, spider monkeys and the bonobo. The gelada has a similar social structure in which many smaller groups come together to form temporary herds of up to 600 monkeys. Humans also form fission-fusion societies. In hunter-gatherer societies, humans form groups which are made up of several individuals that may split up to obtain different resources.
These social systems are affected by three main ecological factors: distribution of resources, group size, and predation. Within a social group there is a balance between cooperation and competition. Cooperative behaviors in many primates species include social grooming (removing skin parasites and cleaning wounds), food sharing, and collective defense against predators or of a territory. Aggressive behaviors often signal competition for food, sleeping sites or mates. Aggression is also used in establishing dominance hierarchies.
In November 2023, scientists reported, for the first time, evidence that groups of primates, particularly bonobos, are capable of cooperating with each other.
Interspecific associations[edit]
Several species of primates are known to associate in the wild. Some of these associations have been extensively studied. In the Tai Forest of Africa several species coordinate anti-predator behavior. These include the Diana monkey, Campbell's mona monkey, lesser spot-nosed monkey, western red colobus, king colobus (western black and white colobus), and sooty mangabey, which coordinate anti-predator alarm calls. Among the predators of these monkeys is the common chimpanzee.
The red-tailed monkey associates with several species, including the western red colobus, blue monkey, Wolf's mona monkey, mantled guereza, black crested mangabey and Allen's swamp monkey. Several of these species are preyed upon by the common chimpanzee.
In South America, squirrel monkeys associate with capuchin monkeys. This may have more to do with foraging benefits to the squirrel monkeys than anti-predation benefits.
Communication[edit]
Further information: Great ape language
Indri lemur wailing
Indri lemur wailing, ogg/Vorbis format.
Howler monkey roaring
Howler monkey roaring, ogg/Vorbis format.
Vervet monkey alarm call
Vervet monkey alarm call, ogg/Vorbis format.
Siamang singing
Siamang singing, ogg/Vorbis format.
Problems playing these files? See media help.
Lemurs, lorises, tarsiers, and New World monkeys rely on olfactory signals for many aspects of social and reproductive behavior. Specialized glands are used to mark territories with pheromones, which are detected by the vomeronasal organ; this process forms a large part of the communication behavior of these primates. In Old World monkeys and apes this ability is mostly vestigial, having regressed as trichromatic eyes evolved to become the main sensory organ. Primates also use vocalizations, gestures, and facial expressions to convey psychological state. Facial musculature is very developed in primates, particularly in monkeys and apes, allowing for complex facial communication. Like humans, chimpanzees can distinguish the faces of familiar and unfamiliar individuals. Hand and arm gestures are also important forms of communication for great apes and a single gesture can have multiple functions.
Primates are a particularly vocal group of mammals. Indris and black-and-white ruffed lemurs make distinctive, loud songs and choruses which maintain territories and act as alarm calls. The Philippine tarsier, has a high-frequency limit of auditory sensitivity of approximately 91 kHz with a dominant frequency of 70 kHz, among the highest recorded for any terrestrial mammal. For Philippine tarsiers, these ultrasonic vocalizations might represent a private channel of communication that subverts detection by predators, prey and competitors, enhances energetic efficiency, or improves detection against low-frequency background noise. Male howler monkeys are among the loudest land mammals as their roars can be heard up to 4.8 km (3.0 mi), and relate to intergroup spacing, territorial protection and possibly mate-guarding. Roars are produced by a modified larynx and enlarged hyoid bone which contains an air sac. The vervet monkey gives a distinct alarm call for each of at least four different predators, and the reactions of other monkeys vary according to the call. Male and female siamangs both possess inflatable pouches in the throat with which pair -bonds use to sing "duets" to each other.
Many non-human primates have the vocal anatomy to produce human speech but lack the proper brain wiring. Vowel-like vocal patterns have been recorded in baboons which has implications for the origin of speech in humans. Consonant- and vowel-like sounds exist in some orangutan calls and they maintain their meaning over great distances. The time range for the evolution of human language and/or its anatomical prerequisites extends, at least in principle, from the phylogenetic divergence of Homo (2.3 to 2.4 million years ago) from Pan (5 to 6 million years ago) to the emergence of full behavioral modernity some 50,000–150,000 years ago. Few dispute that Australopithecus probably lacked vocal communication significantly more sophisticated than that of great apes in general.
Life history[edit]
A crab-eating macaque breastfeeding her baby
Primates have slower rates of development than other mammals. All primate infants are breastfed by their mothers (with the exception of some human cultures and various zoo raised primates which are fed formula) and rely on them for grooming and transportation. In some species, infants are protected and transported by males in the group, particularly males who may be their fathers. Other relatives of the infant, such as siblings and aunts, may participate in its care as well. Most primate mothers cease ovulation while breastfeeding an infant; once the infant is weaned the mother can reproduce again. This often leads to weaning conflict with infants who attempt to continue breastfeeding.
Infanticide is common in polygynous species such as gray langurs and gorillas. Adult males may kill dependent offspring that are not theirs so the female will return to estrus and thus they can sire offspring of their own. Social monogamy in some species may have evolved to combat this behavior. Promiscuity may also lessen the risk of infanticide since paternity becomes uncertain.
Primates have a longer juvenile period between weaning and sexual maturity than other mammals of similar size. Some primates such as galagos and new world monkeys use tree-holes for nesting, and park juveniles in leafy patches while foraging. Other primates follow a strategy of "riding", i.e. carrying individuals on the body while feeding. Adults may construct or use nesting sites, sometimes accompanied by juveniles, for the purpose of resting, a behavior which has developed secondarily in the great apes. During the juvenile period, primates are more susceptible than adults to predation and starvation; they gain experience in feeding and avoiding predators during this time. They learn social and fighting skills, often through playing. Primates, especially females, have longer lifespans than other similarly sized mammals, this may be partially due to their slower metabolisms. Late in life, female catarrhine primates appear to undergo a cessation of reproductive function known as menopause; other groups are less studied.
Diet and feeding[edit]
Leaf eating mantled guereza, a species of black-and-white colobus
A mouse lemur holds a cut piece of fruit in its hands and eats.
Primates exploit a variety of food sources. It has been said that many characteristics of modern primates, including humans, derive from an early ancestor's practice of taking most of its food from the tropical canopy. Most primates include fruit in their diets to obtain easily digested nutrients including carbohydrates and lipids for energy. Primates in the suborder Strepsirrhini (non-tarsier prosimians) are able to synthesize vitamin C, like most other mammals, while primates of the suborder Haplorhini (tarsiers, monkeys and apes) have lost this ability, and require the vitamin in their diet.
Many primates have anatomical specializations that enable them to exploit particular foods, such as fruit, leaves, gum or insects. For example, leaf eaters such as howler monkeys, black-and-white colobuses and sportive lemurs have extended digestive tracts which enable them to absorb nutrients from leaves that can be difficult to digest. Marmosets, which are gum eaters, have strong incisor teeth, enabling them to open tree bark to get to the gum, and claws rather than nails, enabling them to cling to trees while feeding. The aye-aye combines rodent-like teeth with a long, thin middle finger to fill the same ecological niche as a woodpecker. It taps on trees to find insect larvae, then gnaws holes in the wood and inserts its elongated middle finger to pull the larvae out. Some species have additional specializations. For example, the grey-cheeked mangabey has thick enamel on its teeth, enabling it to open hard fruits and seeds that other monkeys cannot. The gelada is the only primate species that feeds primarily on grass.
Hunting[edit]
Humans have traditionally hunted prey for subsistence.
Tarsiers are the only extant obligate carnivorous primates, exclusively eating insects, crustaceans, small vertebrates and snakes (including venomous species). Capuchin monkeys can exploit many different types of plant matter, including fruit, leaves, flowers, buds, nectar and seeds, but also eat insects and other invertebrates, bird eggs, and small vertebrates such as birds, lizards, squirrels and bats.
The common chimpanzee eats an omnivorous frugivorous diet. It prefers fruit above all other food items and even seeks out and eats them when they are not abundant. It also eats leaves and leaf buds, seeds, blossoms, stems, pith, bark and resin. Insects and meat make up a small proportion of their diet, estimated as 2%. The meat consumption includes predation on other primate species, such as the western red colobus monkey. The bonobo is an omnivorous frugivore – the majority of its diet is fruit, but it supplements this with leaves, meat from small vertebrates, such as anomalures, flying squirrels and duikers, and invertebrates. In some instances, bonobos have been shown to consume lower-order primates.
Until the development of agriculture approximately 10,000 years ago, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game, which must be hunted and killed in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus. Around ten thousand years ago, humans developed agriculture, which substantially altered their diet. This change in diet may also have altered human biology; with the spread of dairy farming providing a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults.
As prey[edit]
Predators of primates include various species of carnivorans, birds of prey, reptiles, and other primates. Even gorillas have been recorded as prey. Predators of primates have diverse hunting strategies and as such, primates have evolved several different antipredator adaptations including crypsis, alarm calls and mobbing. Several species have separate alarm calls for different predators such as air-borne or ground-dwelling predators. Predation may have shaped group size in primates as species exposed to higher predation pressures appear to live in larger groups.
Intelligence and cognition[edit]
Main article: Primate cognition
Primates have advanced cognitive abilities: some make tools and use them to acquire food and for social displays; some can perform tasks requiring cooperation, influence and rank; they are status conscious, manipulative and capable of deception; they can recognise kin and conspecifics; and they can learn to use symbols and understand aspects of human language including some relational syntax and concepts of number and numerical sequence. Research in primate cognition explores problem solving, memory, social interaction, a theory of mind, and numerical, spatial, and abstract concepts. Comparative studies show a trend towards higher intelligence going from prosimians to New World monkeys to Old World monkeys, and significantly higher average cognitive abilities in the great apes. However, there is a great deal of variation in each group (e.g., among New World monkeys, both spider and capuchin monkeys have scored highly by some measures), as well as in the results of different studies.
Tool use and manufacture[edit]
Main article: Tool use by animals
Chimpanzees using twigs to dip for ants
Crab-eating macaques with stone tools
In 1960, Jane Goodall observed a chimpanzee poking pieces of grass into a termite mound and then raising the grass to his mouth. After he left, Goodall approached the mound and repeated the behaviour because she was unsure what the chimpanzee was doing. She found that the termites bit onto the grass with their jaws. The chimpanzee had been using the grass as a tool to "fish" or "dip" for termites. There are more limited reports of the closely related bonobo using tools in the wild; it has been claimed they rarely use tools in the wild although they use tools as readily as chimpanzees when in captivity. It has been reported that females, both chimpanzee and bonobo, use tools more avidly than males. Orangutans in Borneo scoop catfish out of small ponds. Over two years, anthropologist Anne Russon observed orangutans learning to jab sticks at catfish to scare them out of the ponds and in to their waiting hands. There are few reports of gorillas using tools in the wild. An adult female western lowland gorilla used a branch as a walking stick apparently to test water depth and to aid her in crossing a pool of water. Another adult female used a detached trunk from a small shrub as a stabilizer during food gathering, and another used a log as a bridge.
The first direct observation of a non-ape primate using a tool in a wild environment occurred in 1988. Primatologist Sue Boinski watched an adult male white-faced capuchin beat a fer-de-lance snake to death with a dead branch. The black-striped capuchin was the first non-ape primate for which routine tool use was documented in the wild; individuals were observed cracking nuts by placing them on a stone anvil and hitting them with another large stone. In Thailand and Myanmar, crab-eating macaques use stone tools to open nuts, oysters and other bivalves, and various types of sea snails. Chacma baboons use stones as weapons; stoning by these baboons is done from the rocky walls of the canyon where they sleep and retreat to when they are threatened. Stones are lifted with one hand and dropped over the side whereupon they tumble down the side of the cliff or fall directly to the canyon floor.
Although they have not been observed to use tools in the wild, lemurs in controlled settings have been shown to be capable of understanding the functional properties of the objects they had been trained to use as tools, performing as well as tool-using haplorhines.
Soon after her initial discovery of tool use, Goodall observed other chimpanzees picking up leafy twigs, stripping off the leaves and using the stems to fish for insects. This change of a leafy twig into a tool was a major discovery. Prior to this, scientists thought that only humans manufactured and used tools, and that this ability was what separated humans from other animals. Chimpanzees have also been observed making "sponges" out of leaves and moss that suck up water. Sumatran orangutans have been observed making and using tools. They will break off a tree branch that is about 30 cm long, snap off the twigs, fray one end and then use the stick to dig in tree holes for termites. In the wild, mandrills have been observed to clean their ears with modified tools. Scientists filmed a large male mandrill at Chester Zoo (UK) stripping down a twig, apparently to make it narrower, and then using the modified stick to scrape dirt from underneath its toenails. Captive gorillas have made a variety of tools.
Ecology[edit]
See also: List of primates by population
Rhesus macaque at Agra Fort, India
Non-human primates primarily live in the tropical latitudes of Africa, Asia, and the Americas. Species that live outside of the tropics include the Japanese macaque which lives in the Japanese islands of Honshū and Hokkaido; the Barbary macaque which lives in North Africa and several species of langur which live in China. Primates tend to live in tropical rainforests but are also found in temperate forests, savannas, deserts, mountains and coastal areas. The number of primate species within tropical areas has been shown to be positively correlated to the amount of rainfall and the amount of rain forest area. Accounting for 25% to 40% of the fruit-eating animals (by weight) within tropical rainforests, primates play an important ecological role by dispersing seeds of many tree species.
Primate habitats span a range of altitudes: the black snub-nosed monkey has been found living in the Hengduan Mountains at altitudes of 4,700 meters (15,400 ft), the mountain gorilla can be found at 4,200 meters (13,200 ft) crossing the Virunga Mountains, and the gelada has been found at elevations of up to 5,000 m (16,000 ft) in the Ethiopian Highlands. Some species interact with aquatic environments and may swim or even dive, including the proboscis monkey, De Brazza's monkey and Allen's swamp monkey. Some primates, such as the rhesus macaque and gray langurs, can exploit human-modified environments and even live in cities.
Interactions between humans and other primates[edit]
Disease transmission[edit]
Close interactions between humans and non-human primates (NHPs) can create pathways for the transmission of zoonotic diseases. Viruses such as Herpesviridae (most notably Herpes B Virus), Poxviridae, measles, ebola, rabies, the Marburg virus and viral hepatitis can be transmitted to humans; in some cases the viruses produce potentially fatal diseases in both humans and non-human primates.
Legal and social status[edit]
Further information: Great ape personhood
Slow lorises are popular in the exotic pet trade, which threatens wild populations.
Only humans are recognized as persons and protected in law by the United Nations Universal Declaration of Human Rights. The legal status of NHPs, on the other hand, is the subject of much debate, with organizations such as the Great Ape Project (GAP) campaigning to award at least some of them legal rights. In June 2008, Spain became the first country in the world to recognize the rights of some NHPs, when its parliament's cross-party environmental committee urged the country to comply with GAP's recommendations, which are that chimpanzees, orangutans and gorillas are not to be used for animal experiments.
Many species of NHP are kept as pets by humans, the Allied Effort to Save Other Primates (AESOP) estimates that around 15,000 NHPs live as exotic pets in the United States. The expanding Chinese middle class has increased demand for NHPs as exotic pets in recent years. Although NHP import for the pet trade was banned in the U.S. in 1975, smuggling still occurs along the United States – Mexico border, with prices ranging from US$3000 for monkeys to $30,000 for apes.
Primates are used as model organisms in laboratories and have been used in space missions. They serve as service animals for disabled humans. Capuchin monkeys can be trained to assist quadriplegic humans; their intelligence, memory, and manual dexterity make them ideal helpers.
NHPs are kept in zoos around the globe. Historically, zoos were primarily a form of entertainment, but more recently have shifted their focus towards conservation, education and research. GAP does not insist that all NHPs should be released from zoos, primarily because captive-born primates lack the knowledge and experience to survive in the wild if released.
Role in scientific research[edit]
Further information: Animal testing on non-human primates and International trade in primates
Sam, a rhesus macaque, was flown to the edge of space by NASA in the 1959 Little Joe 2 flight of Project Mercury.
Thousands of non-human primates are used around the world in research because of their psychological and physiological similarity to humans. In particular, the brains and eyes of NHPs more closely parallel human anatomy than those of any other animals. NHPs are commonly used in preclinical trials, neuroscience, ophthalmology studies, and toxicity studies. Rhesus macaques are often used, as are other macaques, African green monkeys, chimpanzees, baboons, squirrel monkeys, and marmosets, both wild-caught and purpose-bred.
In 2005, GAP reported that 1,280 of the 3,100 NHPs living in captivity in the United States were used for experiments. In 2004, the European Union used around 10,000 NHPs in such experiments; in 2005 in Great Britain, 4,652 experiments were conducted on 3,115 NHPs. Governments of many nations have strict care requirements of NHPs kept in captivity. In the US, federal guidelines extensively regulate aspects of NHP housing, feeding, enrichment, and breeding. European groups such as the European Coalition to End Animal Experiments are seeking a ban on all NHP use in experiments as part of the European Union's review of animal testing legislation.
Extinction threats[edit]
Humans are known to hunt other primates for food, called bushmeat. Pictured are two men who have killed a number of silky sifaka and white-headed brown lemurs.
The International Union for Conservation of Nature (IUCN) lists more than a third of primates as critically endangered or vulnerable. About 60% of primate species are threatened with extinction, including: 87% of species in Madagascar, 73% in Asia, 37% in Africa, and 36% in South and Central America. Additionally, 75% of primate species have decreasing populations. Trade is regulated, as all species are listed by CITES in Appendix II, except 50 species and subspecies listed in Appendix I, which gain full protection from trade.
White-headed lemur (Eulemur albifrons) killed in northeast Madagascar for bushmeat.
Common threats to primate species include deforestation, forest fragmentation, monkey drives (resulting from primate crop raiding), and primate hunting for use in medicines, as pets, and for food. Large-scale tropical forest clearing is widely regarded as the process that most threatens primates. More than 90% of primate species occur in tropical forests. The main cause of forest loss is clearing for agriculture, although commercial logging, subsistence harvesting of timber, mining, and dam construction also contribute to tropical forest destruction. In Indonesia large areas of lowland forest have been cleared to increase palm oil production, and one analysis of satellite imagery concluded that during 1998 and 1999 there was a loss of 1,000 Sumatran orangutans per year in the Leuser Ecosystem alone.
The critically endangered silky sifaka
Primates with a large body size (over 5 kg) are at increased extinction risk due to their greater profitability to poachers compared to smaller primates. They reach sexual maturity later and have a longer period between births. Populations therefore recover more slowly after being depleted by poaching or the pet trade. Data for some African cities show that half of all protein consumed in urban areas comes from the bushmeat trade. Endangered primates such as guenons and the drill are hunted at levels that far exceed sustainable levels. This is due to their large body size, ease of transport and profitability per animal. As farming encroaches on forest habitats, primates feed on the crops, causing the farmers large economic losses. Primate crop raiding gives locals a negative impression of primates, hindering conservation efforts.
Madagascar, home to five endemic primate families, has experienced the greatest extinction of the recent past; since human settlement 1,500 years ago, at least eight classes and fifteen of the larger species have become extinct due to hunting and habitat destruction. Among the primates wiped out were Archaeoindris (a lemur larger than a silverback gorilla) and the families Palaeopropithecidae and Archaeolemuridae.
The critically endangered Sumatran orangutan
In Asia, Hinduism, Buddhism, and Islam prohibit eating primate meat; however, primates are still hunted for food. Some smaller traditional religions allow the consumption of primate meat. The pet trade and traditional medicine also increase demand for illegal hunting. The rhesus macaque, a model organism, was protected after excessive trapping threatened its numbers in the 1960s; the program was so effective that they are now viewed as a pest throughout their range.
In Central and South America forest fragmentation and hunting are the two main problems for primates. Large tracts of forest are now rare in Central America. This increases the amount of forest vulnerable to edge effects such as farmland encroachment, lower levels of humidity and a change in plant life. Movement restriction results in a greater amount of inbreeding, which can cause deleterious effects leading to a population bottleneck, whereby a significant percentage of the population is lost.
There are 21 critically endangered primates, 7 of which have remained on the IUCN's "The World's 25 Most Endangered Primates" list since the year 2000: the silky sifaka, Delacour's langur, the white-headed langur, the gray-shanked douc, the Tonkin snub-nosed monkey, the Cross River gorilla and the Sumatran orangutan. Miss Waldron's red colobus was recently declared extinct when no trace of the subspecies could be found from 1993 to 1999. A few hunters have found and killed individuals since then, but the subspecies' prospects remain bleak.
See also[edit]
Animals portalMammals portalPrimates portal
Arboreal theory
Great Ape Project
Human evolution
International Primate Day
List of primates
List of fossil primates
Monkey Day
Primatology
Footnotes[edit]
^ Although the monophyletic relationship between lemurs and lorisoids is widely accepted, their clade name is not. The term "lemuriform" is used here because it derives from one popular taxonomy that clumps the clade of toothcombed primates into one infraorder and the extinct, non-toothcombed adapiforms into another, both within the suborder Strepsirrhini. However, another popular alternative taxonomy places the lorisoids in their own infraorder, Lorisiformes.
^ Article 6: Everyone has the right to recognition everywhere as a person before the law. | biology | 2473756 | https://sv.wikipedia.org/wiki/Gymnothorax%20panamensis | Gymnothorax panamensis | Gymnothorax panamensis är en fiskart som först beskrevs av Steindachner, 1876. Gymnothorax panamensis ingår i släktet Gymnothorax och familjen Muraenidae. IUCN kategoriserar arten globalt som livskraftig. Inga underarter finns listade i Catalogue of Life.
Källor
Ålartade fiskar
panamensis | swedish | 0.869611 |
humans_closest_relatives_after_primates/Human.txt |
Humans (Homo sapiens) or modern humans are the most common and widespread species of primate, and the last surviving species of the genus Homo. They are great apes characterized by their hairlessness, bipedalism, and high intelligence. Humans have large brains, enabling more advanced cognitive skills that enable them to thrive and adapt in varied environments, develop highly complex tools, and form complex social structures and civilizations. Humans are highly social, with individual humans tending to belong to a multi-layered network of cooperating, distinct, or even competing social groups – from families and peer groups to corporations and political states. As such, social interactions between humans have established a wide variety of values, social norms, languages, and traditions (collectively termed institutions), each of which bolsters human society. Humans are also highly curious: the desire to understand and influence phenomena has motivated humanity's development of science, technology, philosophy, mythology, religion, and other frameworks of knowledge; humans also study themselves through such domains as anthropology, social science, history, psychology, and medicine. As of March 2024, there are estimated to be more than 8 billion humans alive.
Although some scientists equate the term "humans" with all members of the genus Homo, in common usage it generally refers to Homo sapiens, the only extant member. Extinct members of the genus Homo are known as archaic humans, and the term "modern human" is used to distinguish Homo sapiens from archaic humans. Anatomically modern humans emerged around 300,000 years ago in Africa, evolving from Homo heidelbergensis or a similar species. Migrating out of Africa, they gradually replaced and interbred with local populations of archaic humans. Multiple hypotheses for the extinction of archaic human species such as Neanderthals include competition, violence, interbreeding with Homo sapiens, or inability to adapt to climate change.
For most of their history, humans were nomadic hunter-gatherers. Humans began exhibiting behavioral modernity about 160,000–60,000 years ago. The Neolithic Revolution, which began in Southwest Asia around 13,000 years ago (and separately in a few other places), saw the emergence of agriculture and permanent human settlement; in turn, this led to the development of civilization and kickstarted a period of continuous (and ongoing) population growth and rapid technological change. Since then, a number of civilizations have risen and fallen, while a number of sociocultural and technological developments have resulted in significant changes to the human lifestyle.
Genes and the environment influence human biological variation in visible characteristics, physiology, disease susceptibility, mental abilities, body size, and life span. Though humans vary in many traits (such as genetic predispositions and physical features), humans are among the least genetically diverse primates. Any two humans are at least 99% genetically similar. Humans are sexually dimorphic: generally, males have greater body strength and females have a higher body fat percentage. At puberty, humans develop secondary sex characteristics. Females are capable of pregnancy, usually between puberty, at around 12 years old, and menopause, around the age of 50.
Humans are omnivorous, capable of consuming a wide variety of plant and animal material, and have used fire and other forms of heat to prepare and cook food since the time of Homo erectus. Humans can survive for up to eight weeks without food and several days without water. Humans are generally diurnal, sleeping on average seven to nine hours per day. Childbirth is dangerous, with a high risk of complications and death. Often, both the mother and the father provide care for their children, who are helpless at birth.
Humans have a large, highly developed, and complex prefrontal cortex, the region of the brain associated with higher cognition. Humans are highly intelligent and capable of episodic memory; they have flexible facial expressions, self-awareness, and a theory of mind. The human mind is capable of introspection, private thought, imagination, volition, and forming views on existence. This has allowed great technological advancements and complex tool development through complex reasoning and the transmission of knowledge to subsequent generations through language.
Humans' advanced technology has enabled them to spread to all the continents of the globe as well as to outer space, and to command profound influence on the biosphere and environment. The latter has prompted some geologists to demarcate the time from the emergence of human civilization till present as a separate geological epoch: the Anthropocene (with anthropo- deriving from the Ancient Greek word for "human", ἄνθρωπος).
Etymology and definition
Further information: Names for the human species and Human taxonomy
Carl Linnaeus coined the name Homo sapiens and is the type specimen of the species
All modern humans are classified into the species Homo sapiens, coined by Carl Linnaeus in his 1735 work Systema Naturae. The generic name "Homo" is a learned 18th-century derivation from Latin homō, which refers to humans of either sex. The word human can refer to all members of the Homo genus, although in common usage it generally just refers to Homo sapiens, the only extant species. The name "Homo sapiens" means 'wise man' or 'knowledgeable man'. There is disagreement if certain extinct members of the genus, namely Neanderthals, should be included as a separate species of humans or as a subspecies of H. sapiens.
Human is a loanword of Middle English from Old French humain, ultimately from Latin hūmānus, the adjectival form of homō ('man' – in the sense of humanity). The native English term man can refer to the species generally (a synonym for humanity) as well as to human males. It may also refer to individuals of either sex.
Despite the fact that the word animal is colloquially used as an antonym for human, and contrary to a common biological misconception, humans are animals. The word person is often used interchangeably with human, but philosophical debate exists as to whether personhood applies to all humans or all sentient beings, and further if one can lose personhood (such as by going into a persistent vegetative state).
Evolution
Main article: Human evolution
Humans are apes (superfamily Hominoidea). The lineage of apes that eventually gave rise to humans first split from gibbons (family Hylobatidae) and orangutans (genus Pongo), then gorillas (genus Gorilla), and finally, chimpanzees and bonobos (genus Pan). The last split, between the human and chimpanzee–bonobo lineages, took place around 8–4 million years ago, in the late Miocene epoch. During this split, chromosome 2 was formed from the joining of two other chromosomes, leaving humans with only 23 pairs of chromosomes, compared to 24 for the other apes. Following their split with chimpanzees and bonobos, the hominins diversified into many species and at least two distinct genera. All but one of these lineages – representing the genus Homo and its sole extant species Homo sapiens – are now extinct.
Reconstruction of Lucy, the first Australopithecus afarensis skeleton found
The genus Homo evolved from Australopithecus. Though fossils from the transition are scarce, the earliest members of Homo share several key traits with Australopithecus. The earliest record of Homo is the 2.8 million-year-old specimen LD 350-1 from Ethiopia, and the earliest named species are Homo habilis and Homo rudolfensis which evolved by 2.3 million years ago. H. erectus (the African variant is sometimes called H. ergaster) evolved 2 million years ago and was the first archaic human species to leave Africa and disperse across Eurasia. H. erectus also was the first to evolve a characteristically human body plan. Homo sapiens emerged in Africa around 300,000 years ago from a species commonly designated as either H. heidelbergensis or H. rhodesiensis, the descendants of H. erectus that remained in Africa. H. sapiens migrated out of the continent, gradually replacing or interbreeding with local populations of archaic humans. Humans began exhibiting behavioral modernity about 160,000–70,000 years ago, and possibly earlier.
The "out of Africa" migration took place in at least two waves, the first around 130,000 to 100,000 years ago, the second (Southern Dispersal) around 70,000 to 50,000 years ago. H. sapiens proceeded to colonize all the continents and larger islands, arriving in Eurasia 125,000 years ago, Australia around 65,000 years ago, the Americas around 15,000 years ago, and remote islands such as Hawaii, Easter Island, Madagascar, and New Zealand in the years 300 to 1280 CE.
Human evolution was not a simple linear or branched progression but involved interbreeding between related species. Genomic research has shown that hybridization between substantially diverged lineages was common in human evolution. DNA evidence suggests that several genes of Neanderthal origin are present among all non sub-Saharan-African populations, and Neanderthals and other hominins, such as Denisovans, may have contributed up to 6% of their genome to present-day non sub-Saharan-African humans.
Human evolution is characterized by a number of morphological, developmental, physiological, and behavioral changes that have taken place since the split between the last common ancestor of humans and chimpanzees. The most significant of these adaptations are hairlessness, obligate bipedalism, increased brain size and decreased sexual dimorphism (neoteny). The relationship between all these changes is the subject of ongoing debate.
Hominoidea (hominoids, apes)
Hylobatidae (gibbons)
Hominidae (hominids, great apes)
Ponginae
Pongo (orangutans)
Pongo abelii
Pongo tapanuliensis
Pongo pygmaeus
Homininae (hominines)
Gorillini
Gorilla (gorillas)
Gorilla gorilla
Gorilla beringei
Hominini (hominins)
Panina
Pan (chimpanzees)
Pan troglodytes
Pan paniscus
Hominina (homininans)
Homo sapiens (humans)
History
Main article: Human history
Prehistory
Main article: Prehistory
Overview map of the peopling of the world by early human migration during the Upper Paleolithic, following to the Southern Dispersal paradigm
Until about 12,000 years ago, all humans lived as hunter-gatherers. The Neolithic Revolution (the invention of agriculture) first took place in Southwest Asia and spread through large parts of the Old World over the following millennia. It also occurred independently in Mesoamerica (about 6,000 years ago), China, Papua New Guinea, and the Sahel and West Savanna regions of Africa.
Access to food surplus led to the formation of permanent human settlements, the domestication of animals and the use of metal tools for the first time in history. Agriculture and sedentary lifestyle led to the emergence of early civilizations.
Ancient
Main article: Ancient history
Great Pyramids of Giza, Egypt
An urban revolution took place in the 4th millennium BCE with the development of city-states, particularly Sumerian cities located in Mesopotamia. It was in these cities that the earliest known form of writing, cuneiform script, appeared around 3000 BCE. Other major civilizations to develop around this time were Ancient Egypt and the Indus Valley Civilisation. They eventually traded with each other and invented technology such as wheels, plows and sails. Astronomy and mathematics were also developed and the Great Pyramid of Giza was built. There is evidence of a severe drought lasting about a hundred years that may have caused the decline of these civilizations, with new ones appearing in the aftermath. Babylonians came to dominate Mesopotamia while others, such as the Poverty Point culture, Minoans and the Shang dynasty, rose to prominence in new areas.
The Late Bronze Age collapse around 1200 BCE resulted in the disappearance of a number of civilizations and the beginning of the Greek Dark Ages. During this period iron started replacing bronze, leading to the Iron Age.
In the 5th century BCE, history started being recorded as a discipline, which provided a much clearer picture of life at the time. Between the 8th and 6th century BCE, Europe entered the classical antiquity age, a period when ancient Greece and ancient Rome flourished. Around this time other civilizations also came to prominence. The Maya civilization started to build cities and create complex calendars. In Africa, the Kingdom of Aksum overtook the declining Kingdom of Kush and facilitated trade between India and the Mediterranean. In West Asia, the Achaemenid Empire's system of centralized governance became the precursor to many later empires, while the Gupta Empire in India and the Han dynasty in China have been described as golden ages in their respective regions.
Medieval
Main article: Post-classical history
Medieval French manuscript illustration of the three classes of medieval society from the 13th-century Li Livres dou Santé
Following the fall of the Western Roman Empire in 476, Europe entered the Middle Ages. During this period, Christianity and the Church would provide centralized authority and education. In the Middle East, Islam became the prominent religion and expanded into North Africa. It led to an Islamic Golden Age, inspiring achievements in architecture, the revival of old advances in science and technology, and the formation of a distinct way of life. The Christian and Islamic worlds would eventually clash, with the Kingdom of England, the Kingdom of France and the Holy Roman Empire declaring a series of holy wars to regain control of the Holy Land from Muslims.
In the Americas, complex Mississippian societies would arise starting around 800 CE, while further south, the Aztecs and Incas would become the dominant powers. The Mongol Empire would conquer much of Eurasia in the 13th and 14th centuries. Over this same time period, the Mali Empire in Africa grew to be the largest empire on the continent, stretching from Senegambia to Ivory Coast. Oceania would see the rise of the Tuʻi Tonga Empire which expanded across many islands in the South Pacific.
Modern
Main articles: Early modern period and Late modern period
James Watt's steam engine
The early modern period in Europe and the Near East (c. 1450–1800) began with the final defeat of the Byzantine Empire, and the rise of the Ottoman Empire. Meanwhile, Japan entered the Edo period, the Qing dynasty rose in China and the Mughal Empire ruled much of India. Europe underwent the Renaissance, starting in the 15th century, and the Age of Discovery began with the exploring and colonizing of new regions. This includes the British Empire expanding to become the world's largest empire and the colonization of the Americas. This expansion led to the Atlantic slave trade and the genocide of Native American peoples. This period also marked the Scientific Revolution, with great advances in mathematics, mechanics, astronomy and physiology.
The late modern period (1800–present) saw the Technological and Industrial Revolution bring such discoveries as imaging technology, major innovations in transport and energy development. The United States of America underwent great change, going from a small group of colonies to one of the global superpowers. The Napoleonic Wars raged through Europe in the early 1800s, Spain lost most of its colonies in the New World, while Europeans continued expansion into Africa – where European control went from 10% to almost 90% in less than 50 years – and Oceania.
A tenuous balance of power among European nations collapsed in 1914 with the outbreak of the First World War, one of the deadliest conflicts in history. In the 1930s, a worldwide economic crisis led to the rise of authoritarian regimes and a Second World War, involving almost all of the world's countries. The war's destruction led to the collapse of most global empires, leading to widespread decolonization.
Contemporary
Main article: Contemporary history
Following the conclusion of the Second World War in 1945, the Cold War between the USSR and the United States saw a struggle for global influence, including a nuclear arms race and a space race, ending in the collapse of the Soviet Union. The current Information Age, spurred by the development of the Internet and Artificial Intelligence systems, sees the world becoming increasingly globalized and interconnected.
Habitat and population
Further information: Human geography and Demography
Population statisticsMosaic cartogram showing the distribution of the global population based on 2018 UN data. Each of the 15,266 pixels represents the home country of 500,000 people – cartogram by Max Roser for Our World in DataChoropleth showing Population density (people per square kilometer) estimates by 30 arc-second grid in 2020World population8.1 billionPopulation density16/km (41/sq mi) by total area54/km (140/sq mi) by land areaLargest citiesTokyo, Delhi, Shanghai, São Paulo, Mexico City, Cairo, Mumbai, Beijing, Dhaka, Osaka, New York-Newark, Karachi, Buenos Aires, Chongqing, Istanbul, Kolkata, Manila, Lagos, Rio de Janeiro, Tianjin, Kinshasa, Guangzhou, Los Angeles-Long Beach-Santa Ana, Moscow, Shenzhen, Lahore, Bangalore, Paris, Jakarta, Chennai, Lima, Bogota, Bangkok, London
Early human settlements were dependent on proximity to water and – depending on the lifestyle – other natural resources used for subsistence, such as populations of animal prey for hunting and arable land for growing crops and grazing livestock. Modern humans, however, have a great capacity for altering their habitats by means of technology, irrigation, urban planning, construction, deforestation and desertification. Human settlements continue to be vulnerable to natural disasters, especially those placed in hazardous locations and with low quality of construction. Grouping and deliberate habitat alteration is often done with the goals of providing protection, accumulating comforts or material wealth, expanding the available food, improving aesthetics, increasing knowledge or enhancing the exchange of resources.
Humans are one of the most adaptable species, despite having a low or narrow tolerance for many of the earth's extreme environments. Currently the species is present in all eight biogeographical realms, although their presence in the Antarctic realm is very limited to research stations and annually there is a population decline in the winter months of this realm. Humans established their nation-states in the other seven realms, such as for example South Africa, India, Russia, Australia, Fiji, United States and Brazil (each located in a different biogeographical realm).
By using advanced tools and clothing, humans have been able to extend their tolerance to a wide variety of temperatures, humidities, and altitudes. As a result, humans are a cosmopolitan species found in almost all regions of the world, including tropical rainforest, arid desert, extremely cold arctic regions, and heavily polluted cities; in comparison, most other species are confined to a few geographical areas by their limited adaptability. The human population is not, however, uniformly distributed on the Earth's surface, because the population density varies from one region to another, and large stretches of surface are almost completely uninhabited, like Antarctica and vast swathes of the ocean. Most humans (61%) live in Asia; the remainder live in the Americas (14%), Africa (14%), Europe (11%), and Oceania (0.5%).
Within the last century, humans have explored challenging environments such as Antarctica, the deep sea, and outer space. Human habitation within these hostile environments is restrictive and expensive, typically limited in duration, and restricted to scientific, military, or industrial expeditions. Humans have briefly visited the Moon and made their presence felt on other celestial bodies through human-made robotic spacecraft. Since the early 20th century, there has been continuous human presence in Antarctica through research stations and, since 2000, in space through habitation on the International Space Station.
Humans and their domesticated animals represent 96% of all mammalian biomass on earth, whereas all wild mammals represent only 4%.
Estimates of the population at the time agriculture emerged in around 10,000 BC have ranged between 1 million and 15 million. Around 50–60 million people lived in the combined eastern and western Roman Empire in the 4th century AD. Bubonic plagues, first recorded in the 6th century AD, reduced the population by 50%, with the Black Death killing 75–200 million people in Eurasia and North Africa alone. Human population is believed to have reached one billion in 1800. It has since then increased exponentially, reaching two billion in 1930 and three billion in 1960, four in 1975, five in 1987 and six billion in 1999. It passed seven billion in 2011 and passed eight billion in November 2022. It took over two million years of human prehistory and history for the human population to reach one billion and only 207 years more to grow to 7 billion. The combined biomass of the carbon of all the humans on Earth in 2018 was estimated at 60 million tons, about 10 times larger than that of all non-domesticated mammals.
In 2018, 4.2 billion humans (55%) lived in urban areas, up from 751 million in 1950. The most urbanized regions are Northern America (82%), Latin America (81%), Europe (74%) and Oceania (68%), with Africa and Asia having nearly 90% of the world's 3.4 billion rural population. Problems for humans living in cities include various forms of pollution and crime, especially in inner city and suburban slums. Humans have had a dramatic effect on the environment. They are apex predators, being rarely preyed upon by other species. Human population growth, industrialization, land development, overconsumption and combustion of fossil fuels have led to environmental destruction and pollution that significantly contributes to the ongoing mass extinction of other forms of life.
Biology
Anatomy and physiology
Main article: Human body
Diagram of the human skeleton
Most aspects of human physiology are closely homologous to corresponding aspects of animal physiology. The dental formula of humans is: 2.1.2.32.1.2.3. Humans have proportionately shorter palates and much smaller teeth than other primates. They are the only primates to have short, relatively flush canine teeth. Humans have characteristically crowded teeth, with gaps from lost teeth usually closing up quickly in young individuals. Humans are gradually losing their third molars, with some individuals having them congenitally absent.
Humans share with chimpanzees a vestigial tail, appendix, flexible shoulder joints, grasping fingers and opposable thumbs. Humans also have a more barrel-shaped chests in contrast to the funnel shape of other apes, an adaptation for bipedal respiration. Apart from bipedalism and brain size, humans differ from chimpanzees mostly in smelling, hearing and digesting proteins. While humans have a density of hair follicles comparable to other apes, it is predominantly vellus hair, most of which is so short and wispy as to be practically invisible. Humans have about 2 million sweat glands spread over their entire bodies, many more than chimpanzees, whose sweat glands are scarce and are mainly located on the palm of the hand and on the soles of the feet.
It is estimated that the worldwide average height for an adult human male is about 171 cm (5 ft 7 in), while the worldwide average height for adult human females is about 159 cm (5 ft 3 in). Shrinkage of stature may begin in middle age in some individuals but tends to be typical in the extremely aged. Throughout history, human populations have universally become taller, probably as a consequence of better nutrition, healthcare, and living conditions. The average mass of an adult human is 59 kg (130 lb) for females and 77 kg (170 lb) for males. Like many other conditions, body weight and body type are influenced by both genetic susceptibility and environment and varies greatly among individuals.
Humans have a far faster and more accurate throw than other animals. Humans are also among the best long-distance runners in the animal kingdom, but slower over short distances. Humans' thinner body hair and more productive sweat glands help avoid heat exhaustion while running for long distances. Compared to other apes, the human heart produces greater stroke volume and cardiac output and the aorta is proportionately larger.
Genetics
Main article: Human genetics
A graphical representation of the standard human karyotype, including both the female (XX) and male (XY) sex chromosomes (bottom right), as well as the mitochondrial genome (shown to scale as "MT" at bottom left). Further information: Karyotype
Like most animals, humans are a diploid and eukaryotic species. Each somatic cell has two sets of 23 chromosomes, each set received from one parent; gametes have only one set of chromosomes, which is a mixture of the two parental sets. Among the 23 pairs of chromosomes, there are 22 pairs of autosomes and one pair of sex chromosomes. Like other mammals, humans have an XY sex-determination system, so that females have the sex chromosomes XX and males have XY. Genes and environment influence human biological variation in visible characteristics, physiology, disease susceptibility and mental abilities. The exact influence of genes and environment on certain traits is not well understood.
While no humans – not even monozygotic twins – are genetically identical, two humans on average will have a genetic similarity of 99.5%-99.9%. This makes them more homogeneous than other great apes, including chimpanzees. This small variation in human DNA compared to many other species suggests a population bottleneck during the Late Pleistocene (around 100,000 years ago), in which the human population was reduced to a small number of breeding pairs. The forces of natural selection have continued to operate on human populations, with evidence that certain regions of the genome display directional selection in the past 15,000 years.
The human genome was first sequenced in 2001 and by 2020 hundreds of thousands of genomes had been sequenced. In 2012 the International HapMap Project had compared the genomes of 1,184 individuals from 11 populations and identified 1.6 million single nucleotide polymorphisms. African populations harbor the highest number of private genetic variants. While many of the common variants found in populations outside of Africa are also found on the African continent, there are still large numbers that are private to these regions, especially Oceania and the Americas. By 2010 estimates, humans have approximately 22,000 genes. By comparing mitochondrial DNA, which is inherited only from the mother, geneticists have concluded that the last female common ancestor whose genetic marker is found in all modern humans, the so-called mitochondrial Eve, must have lived around 90,000 to 200,000 years ago.
Life cycle
See also: Childbirth and Life expectancy
A 10 mm human embryo at 5 weeks
Most human reproduction takes place by internal fertilization via sexual intercourse, but can also occur through assisted reproductive technology procedures. The average gestation period is 38 weeks, but a normal pregnancy can vary by up to 37 days. Embryonic development in the human covers the first eight weeks of development; at the beginning of the ninth week the embryo is termed a fetus. Humans are able to induce early labor or perform a caesarean section if the child needs to be born earlier for medical reasons. In developed countries, infants are typically 3–4 kg (7–9 lb) in weight and 47–53 cm (19–21 in) in height at birth. However, low birth weight is common in developing countries, and contributes to the high levels of infant mortality in these regions.
Compared with other species, human childbirth is dangerous, with a much higher risk of complications and death. The size of the fetus's head is more closely matched to the pelvis than in other primates. The reason for this is not completely understood, but it contributes to a painful labor that can last 24 hours or more. The chances of a successful labor increased significantly during the 20th century in wealthier countries with the advent of new medical technologies. In contrast, pregnancy and natural childbirth remain hazardous ordeals in developing regions of the world, with maternal death rates approximately 100 times greater than in developed countries.
Both the mother and the father provide care for human offspring, in contrast to other primates, where parental care is mostly done by the mother. Helpless at birth, humans continue to grow for some years, typically reaching sexual maturity at 15 to 17 years of age. The human life span has been split into various stages ranging from three to twelve. Common stages include infancy, childhood, adolescence, adulthood and old age. The lengths of these stages have varied across cultures and time periods but is typified by an unusually rapid growth spurt during adolescence. Human females undergo menopause and become infertile at around the age of 50. It has been proposed that menopause increases a woman's overall reproductive success by allowing her to invest more time and resources in her existing offspring, and in turn their children (the grandmother hypothesis), rather than by continuing to bear children into old age.
The life span of an individual depends on two major factors, genetics and lifestyle choices. For various reasons, including biological/genetic causes, women live on average about four years longer than men. As of 2018, the global average life expectancy at birth of a girl is estimated to be 74.9 years compared to 70.4 for a boy. There are significant geographical variations in human life expectancy, mostly correlated with economic development – for example, life expectancy at birth in Hong Kong is 87.6 years for girls and 81.8 for boys, while in the Central African Republic, it is 55.0 years for girls and 50.6 for boys. The developed world is generally aging, with the median age around 40 years. In the developing world, the median age is between 15 and 20 years. While one in five Europeans is 60 years of age or older, only one in twenty Africans is 60 years of age or older. In 2012, the United Nations estimated that there were 316,600 living centenarians (humans of age 100 or older) worldwide.
Human life stages
Infant boy and girl
Boy and girl before puberty (children)
Adolescent male and female
Adult man and woman
Elderly man and woman
Diet
Main article: Human nutrition
Humans living in Bali, Indonesia, preparing a meal
Humans are omnivorous, capable of consuming a wide variety of plant and animal material. Human groups have adopted a range of diets from purely vegan to primarily carnivorous. In some cases, dietary restrictions in humans can lead to deficiency diseases; however, stable human groups have adapted to many dietary patterns through both genetic specialization and cultural conventions to use nutritionally balanced food sources. The human diet is prominently reflected in human culture and has led to the development of food science.
Until the development of agriculture, Homo sapiens employed a hunter-gatherer method as their sole means of food collection. This involved combining stationary food sources (such as fruits, grains, tubers, and mushrooms, insect larvae and aquatic mollusks) with wild game, which must be hunted and captured in order to be consumed. It has been proposed that humans have used fire to prepare and cook food since the time of Homo erectus. Human domestication of wild plants began about 11,700 years ago, leading to the development of agriculture, a gradual process called the Neolithic Revolution. These dietary changes may also have altered human biology; the spread of dairy farming provided a new and rich source of food, leading to the evolution of the ability to digest lactose in some adults. The types of food consumed, and how they are prepared, have varied widely by time, location, and culture.
In general, humans can survive for up to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days, with a maximum of one week. In 2020 it is estimated 9 million humans die every year from causes directly or indirectly related to starvation. Childhood malnutrition is also common and contributes to the global burden of disease. However, global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed and a few developing countries. Worldwide, over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an "obesity epidemic." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet.
Biological variation
Main article: Human genetic variation
Changes in the number and order of genes (A–D) create genetic diversity within and between population.
There is biological variation in the human species – with traits such as blood type, genetic diseases, cranial features, facial features, organ systems, eye color, hair color and texture, height and build, and skin color varying across the globe. The typical height of an adult human is between 1.4 and 1.9 m (4 ft 7 in and 6 ft 3 in), although this varies significantly depending on sex, ethnic origin, and family bloodlines. Body size is partly determined by genes and is also significantly influenced by environmental factors such as diet, exercise, and sleep patterns.
There is evidence that populations have adapted genetically to various external factors. The genes that allow adult humans to digest lactose are present in high frequencies in populations that have long histories of cattle domestication and are more dependent on cow milk. Sickle cell anemia, which may provide increased resistance to malaria, is frequent in populations where malaria is endemic. Populations that have for a very long time inhabited specific climates tend to have developed specific phenotypes that are beneficial for those environments – short stature and stocky build in cold regions, tall and lanky in hot regions, and with high lung capacities or other adaptations at high altitudes. Some populations have evolved highly unique adaptations to very specific environmental conditions, such as those advantageous to ocean-dwelling lifestyles and freediving in the Bajau.
Human hair ranges in color from red to blond to brown to black, which is the most frequent. Hair color depends on the amount of melanin, with concentrations fading with increased age, leading to grey or even white hair. Skin color can range from darkest brown to lightest peach, or even nearly white or colorless in cases of albinism. It tends to vary clinally and generally correlates with the level of ultraviolet radiation in a particular geographic area, with darker skin mostly around the equator. Skin darkening may have evolved as protection against ultraviolet solar radiation. Light skin pigmentation protects against depletion of vitamin D, which requires sunlight to make. Human skin also has a capacity to darken (tan) in response to exposure to ultraviolet radiation.
A Libyan, a Nubian, a Syrian, and an Egyptian, drawing by an unknown artist after a mural of the tomb of Seti I
There is relatively little variation between human geographical populations, and most of the variation that occurs is at the individual level. Much of human variation is continuous, often with no clear points of demarcation. Genetic data shows that no matter how population groups are defined, two people from the same population group are almost as different from each other as two people from any two different population groups. Dark-skinned populations that are found in Africa, Australia, and South Asia are not closely related to each other.
Genetic research has demonstrated that human populations native to the African continent are the most genetically diverse and genetic diversity decreases with migratory distance from Africa, possibly the result of bottlenecks during human migration. These non-African populations acquired new genetic inputs from local admixture with archaic populations and have much greater variation from Neanderthals and Denisovans than is found in Africa, though Neanderthal admixture into African populations may be underestimated. Furthermore, recent studies have found that populations in sub-Saharan Africa, and particularly West Africa, have ancestral genetic variation which predates modern humans and has been lost in most non-African populations. Some of this ancestry is thought to originate from admixture with an unknown archaic hominin that diverged before the split of Neanderthals and modern humans.
Humans are a gonochoric species, meaning they are divided into male and female sexes. The greatest degree of genetic variation exists between males and females. While the nucleotide genetic variation of individuals of the same sex across global populations is no greater than 0.1%–0.5%, the genetic difference between males and females is between 1% and 2%. Males on average are 15% heavier and 15 cm (6 in) taller than females. On average, men have about 40–50% more upper body strength and 20–30% more lower body strength than women at the same weight, due to higher amounts of muscle and larger muscle fibers. Women generally have a higher body fat percentage than men. Women have lighter skin than men of the same population; this has been explained by a higher need for vitamin D in females during pregnancy and lactation. As there are chromosomal differences between females and males, some X and Y chromosome-related conditions and disorders only affect either men or women. After allowing for body weight and volume, the male voice is usually an octave deeper than the female voice. Women have a longer life span in almost every population around the world. There are intersex conditions in the human population, however these are rare.
Psychology
Main article: Psychology
Drawing of the human brain, showing several important structures
The human brain, the focal point of the central nervous system in humans, controls the peripheral nervous system. In addition to controlling "lower", involuntary, or primarily autonomic activities such as respiration and digestion, it is also the locus of "higher" order functioning such as thought, reasoning, and abstraction. These cognitive processes constitute the mind, and, along with their behavioral consequences, are studied in the field of psychology.
Humans have a larger and more developed prefrontal cortex than other primates, the region of the brain associated with higher cognition. This has led humans to proclaim themselves to be more intelligent than any other known species. Objectively defining intelligence is difficult, with other animals adapting senses and excelling in areas that humans are unable to.
There are some traits that, although not strictly unique, do set humans apart from other animals. Humans may be the only animals who have episodic memory and who can engage in "mental time travel". Even compared with other social animals, humans have an unusually high degree of flexibility in their facial expressions. Humans are the only animals known to cry emotional tears. Humans are one of the few animals able to self-recognize in mirror tests and there is also debate over to what extent humans are the only animals with a theory of mind.
Sleep and dreaming
Main articles: Sleep and Dream
Humans are generally diurnal. The average sleep requirement is between seven and nine hours per day for an adult and nine to ten hours per day for a child; elderly people usually sleep for six to seven hours. Having less sleep than this is common among humans, even though sleep deprivation can have negative health effects. A sustained restriction of adult sleep to four hours per day has been shown to correlate with changes in physiology and mental state, including reduced memory, fatigue, aggression, and bodily discomfort.
During sleep humans dream, where they experience sensory images and sounds. Dreaming is stimulated by the pons and mostly occurs during the REM phase of sleep. The length of a dream can vary, from a few seconds up to 30 minutes. Humans have three to five dreams per night, and some may have up to seven. Dreamers are more likely to remember the dream if awakened during the REM phase. The events in dreams are generally outside the control of the dreamer, with the exception of lucid dreaming, where the dreamer is self-aware. Dreams can at times make a creative thought occur or give a sense of inspiration.
Consciousness and thought
Main articles: Consciousness and Cognition
Human consciousness, at its simplest, is sentience or awareness of internal or external existence. Despite centuries of analyses, definitions, explanations and debates by philosophers and scientists, consciousness remains puzzling and controversial, being "at once the most familiar and most mysterious aspect of our lives". The only widely agreed notion about the topic is the intuition that it exists. Opinions differ about what exactly needs to be studied and explained as consciousness. Some philosophers divide consciousness into phenomenal consciousness, which is sensory experience itself, and access consciousness, which can be used for reasoning or directly controlling actions. It is sometimes synonymous with 'the mind', and at other times, an aspect of it. Historically it is associated with introspection, private thought, imagination and volition. It now often includes some kind of experience, cognition, feeling or perception. It may be 'awareness', or 'awareness of awareness', or self-awareness. There might be different levels or orders of consciousness, or different kinds of consciousness, or just one kind with different features.
The process of acquiring knowledge and understanding through thought, experience, and the senses is known as cognition. The human brain perceives the external world through the senses, and each individual human is influenced greatly by his or her experiences, leading to subjective views of existence and the passage of time. The nature of thought is central to psychology and related fields. Cognitive psychology studies cognition, the mental processes underlying behavior. Largely focusing on the development of the human mind through the life span, developmental psychology seeks to understand how people come to perceive, understand, and act within the world and how these processes change as they age. This may focus on intellectual, cognitive, neural, social, or moral development. Psychologists have developed intelligence tests and the concept of intelligence quotient in order to assess the relative intelligence of human beings and study its distribution among population.
Motivation and emotion
Main articles: Motivation and Emotion
Illustration of grief from Charles Darwin's 1872 book The Expression of the Emotions in Man and Animals
Human motivation is not yet wholly understood. From a psychological perspective, Maslow's hierarchy of needs is a well-established theory that can be defined as the process of satisfying certain needs in ascending order of complexity. From a more general, philosophical perspective, human motivation can be defined as a commitment to, or withdrawal from, various goals requiring the application of human ability. Furthermore, incentive and preference are both factors, as are any perceived links between incentives and preferences. Volition may also be involved, in which case willpower is also a factor. Ideally, both motivation and volition ensure the selection, striving for, and realization of goals in an optimal manner, a function beginning in childhood and continuing throughout a lifetime in a process known as socialization.
Emotions are biological states associated with the nervous system brought on by neurophysiological changes variously associated with thoughts, feelings, behavioral responses, and a degree of pleasure or displeasure. They are often intertwined with mood, temperament, personality, disposition, creativity, and motivation. Emotion has a significant influence on human behavior and their ability to learn. Acting on extreme or uncontrolled emotions can lead to social disorder and crime, with studies showing criminals may have a lower emotional intelligence than normal.
Emotional experiences perceived as pleasant, such as joy, interest or contentment, contrast with those perceived as unpleasant, like anxiety, sadness, anger, and despair. Happiness, or the state of being happy, is a human emotional condition. The definition of happiness is a common philosophical topic. Some define it as experiencing the feeling of positive emotional affects, while avoiding the negative ones. Others see it as an appraisal of life satisfaction or quality of life. Recent research suggests that being happy might involve experiencing some negative emotions when humans feel they are warranted.
Sexuality and love
Main articles: Human sexuality and Love
Human parents often display familial love for their children.
For humans, sexuality involves biological, erotic, physical, emotional, social, or spiritual feelings and behaviors. Because it is a broad term, which has varied with historical contexts over time, it lacks a precise definition. The biological and physical aspects of sexuality largely concern the human reproductive functions, including the human sexual response cycle. Sexuality also affects and is affected by cultural, political, legal, philosophical, moral, ethical, and religious aspects of life. Sexual desire, or libido, is a basic mental state present at the beginning of sexual behavior. Studies show that men desire sex more than women and masturbate more often.
Humans can fall anywhere along a continuous scale of sexual orientation, although most humans are heterosexual. While homosexual behavior occurs in some other animals, only humans and domestic sheep have so far been found to exhibit exclusive preference for same-sex relationships. Most evidence supports nonsocial, biological causes of sexual orientation, as cultures that are very tolerant of homosexuality do not have significantly higher rates of it. Research in neuroscience and genetics suggests that other aspects of human sexuality are biologically influenced as well.
Love most commonly refers to a feeling of strong attraction or emotional attachment. It can be impersonal (the love of an object, ideal, or strong political or spiritual connection) or interpersonal (love between humans). When in love dopamine, norepinephrine, serotonin and other chemicals stimulate the brain's pleasure center, leading to side effects such as increased heart rate, loss of appetite and sleep, and an intense feeling of excitement.
Culture
Main articles: Culture and Cultural universal
Human society statisticsMost widely spoken languagesEnglish, Mandarin Chinese, Hindi, Spanish, Standard Arabic, Bengali, French, Russian, Portuguese, UrduMost practiced religionsChristianity, Islam, Hinduism, Buddhism, folk religions, Sikhism, Judaism, unaffiliated
Humanity's unprecedented set of intellectual skills were a key factor in the species' eventual technological advancement and concomitant domination of the biosphere. Disregarding extinct hominids, humans are the only animals known to teach generalizable information, innately deploy recursive embedding to generate and communicate complex concepts, engage in the "folk physics" required for competent tool design, or cook food in the wild. Teaching and learning preserves the cultural and ethnographic identity of human societies. Other traits and behaviors that are mostly unique to humans include starting fires, phoneme structuring and vocal learning.
Language
Main article: Language
Principal language families of the world (and in some cases geographic groups of families). For greater detail, see Distribution of languages in the world.
While many species communicate, language is unique to humans, a defining feature of humanity, and a cultural universal. Unlike the limited systems of other animals, human language is open – an infinite number of meanings can be produced by combining a limited number of symbols. Human language also has the capacity of displacement, using words to represent things and happenings that are not presently or locally occurring but reside in the shared imagination of interlocutors.
Language differs from other forms of communication in that it is modality independent; the same meanings can be conveyed through different media, audibly in speech, visually by sign language or writing, and through tactile media such as braille. Language is central to the communication between humans, and to the sense of identity that unites nations, cultures and ethnic groups. There are approximately six thousand different languages currently in use, including sign languages, and many thousands more that are extinct.
The arts
Main article: The arts
Human arts can take many forms including visual, literary, and performing. Visual art can range from paintings and sculptures to film, fashion design, and architecture. Literary arts can include prose, poetry, and dramas. The performing arts generally involve theatre, music, and dance. Humans often combine the different forms (for example, music videos). Other entities that have been described as having artistic qualities include food preparation, video games, and medicine. As well as providing entertainment and transferring knowledge, the arts are also used for political purposes.
The Deluge tablet of the Gilgamesh epic in Akkadian
Art is a defining characteristic of humans and there is evidence for a relationship between creativity and language. The earliest evidence of art was shell engravings made by Homo erectus 300,000 years before modern humans evolved. Art attributed to H. sapiens existed at least 75,000 years ago, with jewellery and drawings found in caves in South Africa. There are various hypotheses as to why humans have adapted to the arts. These include allowing them to better problem solve issues, providing a means to control or influence other humans, encouraging cooperation and contribution within a society or increasing the chance of attracting a potential mate. The use of imagination developed through art, combined with logic may have given early humans an evolutionary advantage.
Evidence of humans engaging in musical activities predates cave art and so far music has been practiced by virtually all known human cultures. There exists a wide variety of music genres and ethnic musics; with humans' musical abilities being related to other abilities, including complex social human behaviours. It has been shown that human brains respond to music by becoming synchronized with the rhythm and beat, a process called entrainment. Dance is also a form of human expression found in all cultures and may have evolved as a way to help early humans communicate. Listening to music and observing dance stimulates the orbitofrontal cortex and other pleasure sensing areas of the brain.
Unlike speaking, reading and writing does not come naturally to humans and must be taught. Still, literature has been present before the invention of words and language, with 30,000-year-old paintings on walls inside some caves portraying a series of dramatic scenes. One of the oldest surviving works of literature is the Epic of Gilgamesh, first engraved on ancient Babylonian tablets about 4,000 years ago. Beyond simply passing down knowledge, the use and sharing of imaginative fiction through stories might have helped develop humans' capabilities for communication and increased the likelihood of securing a mate. Storytelling may also be used as a way to provide the audience with moral lessons and encourage cooperation.
Tools and technologies
Main articles: Tool and Technology
The SCMaglev, the fastest train in the world clocking in at 603 km/h (375 mph) as of 2015
Stone tools were used by proto-humans at least 2.5 million years ago. The use and manufacture of tools has been put forward as the ability that defines humans more than anything else and has historically been seen as an important evolutionary step. The technology became much more sophisticated about 1.8 million years ago, with the controlled use of fire beginning around 1 million years ago. The wheel and wheeled vehicles appeared simultaneously in several regions some time in the fourth millennium BC. The development of more complex tools and technologies allowed land to be cultivated and animals to be domesticated, thus proving essential in the development of agriculture – what is known as the Neolithic Revolution.
China developed paper, the printing press, gunpowder, the compass and other important inventions. The continued improvements in smelting allowed forging of copper, bronze, iron and eventually steel, which is used in railways, skyscrapers and many other products. This coincided with the Industrial Revolution, where the invention of automated machines brought major changes to humans' lifestyles. Modern technology is observed as progressing exponentially, with major innovations in the 20th century including: electricity, penicillin, semiconductors, internal combustion engines, the Internet, nitrogen fixing fertilisers, airplanes, computers, automobiles, contraceptive pills, nuclear fission, the green revolution, radio, scientific plant breeding, rockets, air conditioning, television and the assembly line.
Religion and spirituality
Main articles: Religion and Spirituality
Shango, the Orisha of fire, lightning, and thunder, in the Yoruba religion, depicted on horseback
Definitions of religion vary; according to one definition, a religion is a belief system concerning the supernatural, sacred or divine, and practices, values, institutions and rituals associated with such belief. Some religions also have a moral code. The evolution and the history of the first religions have become areas of active scientific investigation. Credible evidence of religious behaviour dates to the Middle Paleolithic era (45–200 thousand years ago). It may have evolved to play a role in helping enforce and encourage cooperation between humans.
Religion manifests in diverse forms. Religion can include a belief in life after death, the origin of life, the nature of the universe (religious cosmology) and its ultimate fate (eschatology), and moral or ethical teachings. Views on transcendence and immanence vary substantially; traditions variously espouse monism, deism, pantheism, and theism (including polytheism and monotheism).
Although measuring religiosity is difficult, a majority of humans profess some variety of religious or spiritual belief. In 2015 the plurality were Christian followed by Muslims, Hindus and Buddhists. As of 2015, about 16%, or slightly under 1.2 billion humans, were irreligious, including those with no religious beliefs or no identity with any religion.
Science and philosophy
Main articles: Science and Philosophy
The Dunhuang map, a star map showing the North Polar region. China circa 700.
An aspect unique to humans is their ability to transmit knowledge from one generation to the next and to continually build on this information to develop tools, scientific laws and other advances to pass on further. This accumulated knowledge can be tested to answer questions or make predictions about how the universe functions and has been very successful in advancing human ascendancy.
Aristotle has been described as the first scientist, and preceded the rise of scientific thought through the Hellenistic period. Other early advances in science came from the Han Dynasty in China and during the Islamic Golden Age. The scientific revolution, near the end of the Renaissance, led to the emergence of modern science.
A chain of events and influences led to the development of the scientific method, a process of observation and experimentation that is used to differentiate science from pseudoscience. An understanding of mathematics is unique to humans, although other species of animals have some numerical cognition. All of science can be divided into three major branches, the formal sciences (e.g., logic and mathematics), which are concerned with formal systems, the applied sciences (e.g., engineering, medicine), which are focused on practical applications, and the empirical sciences, which are based on empirical observation and are in turn divided into natural sciences (e.g., physics, chemistry, biology) and social sciences (e.g., psychology, economics, sociology).
Philosophy is a field of study where humans seek to understand fundamental truths about themselves and the world in which they live. Philosophical inquiry has been a major feature in the development of humans' intellectual history. It has been described as the "no man's land" between definitive scientific knowledge and dogmatic religious teachings. Philosophy relies on reason and evidence, unlike religion, but does not require the empirical observations and experiments provided by science. Major fields of philosophy include metaphysics, epistemology, logic, and axiology (which includes ethics and aesthetics).
Society
Main article: Society
Humans often live in family-based social structures
Society is the system of organizations and institutions arising from interaction between humans. Humans are highly social and tend to live in large complex social groups. They can be divided into different groups according to their income, wealth, power, reputation and other factors. The structure of social stratification and the degree of social mobility differs, especially between modern and traditional societies. Human groups range from the size of families to nations. The first form of human social organization is thought to have resembled hunter-gatherer band societies.
Gender
Main article: Gender
Human societies typically exhibit gender identities and gender roles that distinguish between masculine and feminine characteristics and prescribe the range of acceptable behaviours and attitudes for their members based on their sex. The most common categorisation is a gender binary of men and women. Many societies recognise a third gender, or less commonly a fourth or fifth. In some other societies, non-binary is used as an umbrella term for a range of gender identities that are not solely male or female.
Gender roles are often associated with a division of norms, practices, dress, behavior, rights, duties, privileges, status, and power, with men enjoying more rights and privileges than women in most societies, both today and in the past. As a social construct, gender roles are not fixed and vary historically within a society. Challenges to predominant gender norms have recurred in many societies. Little is known about gender roles in the earliest human societies. Early modern humans probably had a range of gender roles similar to that of modern cultures from at least the Upper Paleolithic, while the Neanderthals were less sexually dimorphic and there is evidence that the behavioural difference between males and females was minimal.
Kinship
Main article: Kinship
All human societies organize, recognize and classify types of social relationships based on relations between parents, children and other descendants (consanguinity), and relations through marriage (affinity). There is also a third type applied to godparents or adoptive children (fictive). These culturally defined relationships are referred to as kinship. In many societies, it is one of the most important social organizing principles and plays a role in transmitting status and inheritance. All societies have rules of incest taboo, according to which marriage between certain kinds of kin relations are prohibited, and some also have rules of preferential marriage with certain kin relations.
Ethnicity
Main article: Ethnic group
Human ethnic groups are a social category that identifies together as a group based on shared attributes that distinguish them from other groups. These can be a common set of traditions, ancestry, language, history, society, culture, nation, religion, or social treatment within their residing area. Ethnicity is separate from the concept of race, which is based on physical characteristics, although both are socially constructed. Assigning ethnicity to a certain population is complicated, as even within common ethnic designations there can be a diverse range of subgroups, and the makeup of these ethnic groups can change over time at both the collective and individual level. Also, there is no generally accepted definition of what constitutes an ethnic group. Ethnic groupings can play a powerful role in the social identity and solidarity of ethnopolitical units. This has been closely tied to the rise of the nation state as the predominant form of political organization in the 19th and 20th centuries.
Government and politics
Main articles: Government and Politics
The United Nations headquarters in New York City, which houses one of the world's largest political organizations
As farming populations gathered in larger and denser communities, interactions between these different groups increased. This led to the development of governance within and between the communities. Humans have evolved the ability to change affiliation with various social groups relatively easily, including previously strong political alliances, if doing so is seen as providing personal advantages. This cognitive flexibility allows individual humans to change their political ideologies, with those with higher flexibility less likely to support authoritarian and nationalistic stances.
Governments create laws and policies that affect the citizens that they govern. There have been many forms of government throughout human history, each having various means of obtaining power and the ability to exert diverse controls on the population. Approximately 47% of humans live in some form of a democracy, 17% in a hybrid regime, and 37% in an authoritarian regime. Many countries belong to international organizations and alliances; the largest of these is the United Nations, with 193 member states.
Trade and economics
Main articles: Trade and Economics
The Silk Road (red) and spice trade routes (blue)
Trade, the voluntary exchange of goods and services, is seen as a characteristic that differentiates humans from other animals and has been cited as a practice that gave Homo sapiens a major advantage over other hominids. Evidence suggests early H. sapiens made use of long-distance trade routes to exchange goods and ideas, leading to cultural explosions and providing additional food sources when hunting was sparse, while such trade networks did not exist for the now extinct Neanderthals. Early trade likely involved materials for creating tools like obsidian. The first truly international trade routes were around the spice trade through the Roman and medieval periods.
Early human economies were more likely to be based around gift giving instead of a bartering system. Early money consisted of commodities; the oldest being in the form of cattle and the most widely used being cowrie shells. Money has since evolved into governmental issued coins, paper and electronic money. Human study of economics is a social science that looks at how societies distribute scarce resources among different people. There are massive inequalities in the division of wealth among humans; the eight richest humans are worth the same monetary value as the poorest half of all the human population.
Conflict
Further information: War and Violence
American troops landing at Normandy, WWII.
Humans commit violence on other humans at a rate comparable to other primates, but have an increased preference for killing adults, infanticide being more common among other primates. Phylogenetic analysis predicts that 2% of early H. sapiens would be murdered, rising to 12% during the medieval period, before dropping to below 2% in modern times. There is great variation in violence between human populations with rates of homicide in societies that have legal systems and strong cultural attitudes against violence at about 0.01%.
The willingness of humans to kill other members of their species en masse through organized conflict (i.e., war) has long been the subject of debate. One school of thought holds that war evolved as a means to eliminate competitors, and has always been an innate human characteristic. Another suggests that war is a relatively recent phenomenon and has appeared due to changing social conditions. While not settled, current evidence indicates warlike predispositions only became common about 10,000 years ago, and in many places much more recently than that. War has had a high cost on human life; it is estimated that during the 20th century, between 167 million and 188 million people died as a result of war. War casualty data is less reliable for pre-medieval times, especially global figures. But compared with any period over the past 600 years, the last ~80 years (post 1946), has seen a very significant drop in global military and civilian death rates due to armed conflict.
See also
Mammals portalEvolutionary biology portalScience portal
List of human evolution fossils
Timeline of human evolution
Notes
^ The world population and population density statistics are updated automatically from a template that uses the CIA World Factbook and United Nations World Population Prospects.
^ Cities with over 10 million inhabitants as of 2018.
^ Traditionally this has been explained by conflicting evolutionary pressures involved in bipedalism and encephalization (called the obstetrical dilemma), but recent research suggest it might be more complicated than that. | biology | 494108 | https://no.wikipedia.org/wiki/Menneske | Menneske | ? H. s. denisova
† H. s. idaltu
H. s. sapiens
Menneske (Homo sapiens) er en art med tobeinte primater (Primates) i familien av store aper (Hominidae) og tilhører menneskeslekten (Homo). Det vitenskapelige navnet kommer fra latin og betyr «det tenkende mennesket». Nålevende mennesker tilhører underarten H. s. sapiens, alle tidligere underarter av vår art er dødd ut eller absorbert i den moderne befolkningen. Menneske kan være både primærkonsument, sekundærkonsument, tertiærkonsument og toppkonsument i en næringskjede.
Karakteristisk for mennesker er artens kombinasjon av å gå på to bein (tobeint), tilpasningsevne (som klær og verktøy), finmotorikk (hender og fingre), evne til å tenke abstrakt (å vise følelser og empati [medfølelse]), skjelne årsakssammenheng (kausalitet), tolke språk og symboler og eventuelt selvbevissthet. Ingen av disse egenskapene er egentlig unike for mennesker individuelt, men finnes også i ulike dyrearter – fra insekter til andre primater og hvaler. Sammen har de satt mennesket i stand til å utvikle samfunn, filosofi, religion, vitenskap, teknologi og kunst.
Mennesker har utviklet seg i forhold til andre arter og har over tid kommet til å dominere utviklingen på planeten Jorden. Som et sosialt vesen har dets strukturer for sivilisasjon og samfunn blitt styrt ved hjelp av politikk, dens kultur og oppfatning av omverdenen ved hjelp av fenomener som religion, filosofi og vitenskapelig utvikling. Gjennom språket har arten også kunnet dokumentere funn, oppdagelser, oppfinnelser og sin egen historie.
Studiet av mennesker er vanligvis delt inn i ulike fagområder. Studiet av mennesker kalles antropologi og studiet av menneskelig evolusjon kalles paleoantropologi. Studiet av menneskelig atferd kan gjøres innenfor psykologi og sosiologi, mens studiet basert på nøytrale etologiske perspektiver (atferdsbiologi) kalles humanetologi. Studiet av menneskelig språk kalles lingvistikk. Studiet av menneskers helse og mer kalles menneskelig medisin, og studiet av dens kropp kan beskrives i menneskelig anatomi og fysiologi. Menneskelig reproduksjon er relatert til både genetikk og seksualitet.
Biologi
Det moderne mennesket har mulighet for å bruke språk på et meget høyt nivå, og har en høyt utviklet hjerne som er i stand til utstrakt abstrakt tenkning og bevissthet. Denne mentale kapasiteten, kombinert med en oppreist kroppsholdning som frigjør dets øvre lemmer til andre aktiviteter enn gange, har gjort mennesket i stand til å bruke verktøy i større grad enn noen annen kjent dyreart. DNA-baserte beviser indikerer at moderne mennesker oppstod i Afrika for omtrent år siden. Mennesker befolker nå samtlige kontinenter og har per 2022 en total populasjon på over 7.8 milliarder individer.
Studiet av mennesket skjer både i naturvitenskapene (humanbiologi), samfunnsvitenskapene (antropologi) og medisin (inkl. psykologi).
Beskrivelse
Et voksent menneske har ca. 1,8 m² hud, 32 tenner, ca. 600 muskler, 206 knokler, over 100 ledd, km blodårer samt 13 milliarder nerveceller. Mennesket har 4–6 liter blod som inneholder omtrent 25 billioner røde blodlegemer. Hjernen veier gjennomsnittlig gram. Mennesket har opp til 5 millioner hår, like mange som en sjimpanse eller gorilla. I motsetning til hos dem, er kroppshårene hos menneske tynne og kortvokste, slik at mennesket framstår som nakent i forhold til sine slektninger.
Mennesket er en svært variabel art. Gjennomsnittsvekten på voksne individer varierer mellom 40 kg hos noen tropiske folkeslag til opp mot 70 kg hos enkelte nordlige grupper. Størrelsesforskjellen på kjønnene er omkring 20 %, større enn hos sjimpanse, men mindre enn det vi finner hos gorilla og orangutang.
Med unntak av ryggsøylen og den store hjerneskallen er menneskekroppen lite spesialisert, og likner den vi finner hos de fleste primater. Øynene er foroverrettet. Tannsettet er noe redusert i forhold til primitive pattedyr, og mangler de lange hjørnetennene som er vanlig for øvrige primater. Hele tannarden er relativt liten og tilbaketrukket i forhold til slektningene, slik at den nederste del av underkjeven stikker fram som en hake. Dette er trolig en tilpasning til å spise mat som må tygges «sideveis», slik som frø og røtter. Fordøyelsessystemet er ganske enkelt og mangler tilpasninger for mer næringsfattig kost slik vi finner det hos gressetere. Som andre primater har mennesket relativt lite spesialiserte lemmer med fem fingre/tær på hver ekstremitet og kragebein. Menneskets føtter er tilpasset til å gå på hele fotsålen (sålegjenger), og mangler tilpasning til klatring slik vi finner hos andre primater.
Evolusjon og systematikk
Biologisk sett utgjør helheten av alle mennesker en art.
Denne ga Linné det vitenskapelige navnet Homo sapiens (latin: i betydningen «det kloke mennesket»).
Menneskets plass i naturen
Menneskets plass i naturen har fra oldtiden av vært et stridstema. I mange religioner, eksempelvis åsatru, gresk mytologi, kristendom og islam blir mennesket beskrevet som en skapning som er skapt (eller har oppstått) spesielt og løsrevet fra den øvrige naturen. Likevel er likhetene med andre levende organismer ikke til å overse, og allerede Aristoteles grupperte mennesket i dyreriket.
Linné plasserte i sitt verk Systema Naturae menneskene blant herredyrene (primater), i samme biologiske slekt som sjimpanse og orangutang. Denne plasseringen var omstridt i hans samtid, men på forespørsel fra biskopen i Uppsala, skrev han: Jeg kan ikke se at det er noen generiske forskjeller. Med «generisk» viste han til de egenskapene som skiller en slekt (genus på latin) fra en annen. Ideen om mennesket som en primat har holdt stand også i lys av de siste to hundre års forskning. Med Charles Darwins evolusjonsteori fikk man for første gang en etterprøvbar teori om stamtrær og slektskap, og menneskets fortid er i dag ganske godt beskrevet gjennom fossilfunn.
Klassifikasjon
Rike: Animalia (dyreriket)
Rekke: Chordata (ryggstrengdyr)
Klasse: Mammalia (pattedyr)
Orden: Primates (primater)
Familie: Hominidae (store aper)
Slekt: Homo (menneskeslekten)
Art: H. sapiens (menneske)
Underart: H. s. sapiens (det moderne mennesket)
Menneske hører også med i en rekke grupper som faller mellom de formelle kategoriene, slik som infraordenen høyere aper, underklassen placentale pattedyr, overklassen amniondyr, overrekken deuterostomier, gruppene opisthokonter og eukaryoter.
Spredning av mennesker
Menneskeaper
Blant menneskeapene er sjimpanser menneskets nærmeste slektninger. Inntil for om lag 12 millioner år siden delte menneskene sin evolusjonære historie med sjimpansene og gorilla. Mennesket og sjimpansene har hatt en komplisert artsdannelsesprosess fra 8 til 4 millioner år siden, der populasjoner ser ut til å ha skilt lag for så å blande seg igjen i flere omganger. Etter dette «skilte de lag», dvs. at menneskene fikk en stamform som de ikke deler med andre menneskeaper. Det finnes flere fossiler som er kandidat til stamformen til menneske og sjimpanser, men disse er svært fragmentariske og det er per i dag usikkert nøyaktig hvem som representerer våre forfedre, sjimpansens forfedre og utdødde sidegreiner. Det finnes derimot godt med fossilt materiale fra utdødde arter som står nærmere mennesker enn andre aper, slik som Australopithecus afarensis og Homo erectus.
Noen av disse er utdødde sidegrener, som vil si at de ikke etterlot seg avkom som har overlevd til i dag. Andre er menneskenes direkte stamformer. Disse er ikke i egentlig forstand «dødd ut» (fordi de jo har etterlatt seg avkom), men har gjennomgått så store endringer at de ikke lenger er gjenkjennelige, såkalte krono-arter. For mange av disse fossile artene er imidlertid statusen usikker. Det vil si at man ikke med sikkerhet vet om de representerte en sidegren, eller om de kan ha bidratt med avkom til nåtidens menneskeart. Hva som har utgjort arter og hva som bare har vært variasjoner innfor en gruppe er også usikkert.
Førmennesker (Australopithecus)
Noen av Australopithecus-artene, som levde for 4,2–1,2 millioner år siden, er f.eks. med sikkerhet sidegrener (bl.a. A. boisei og A. robustus), andre kan ha vært menneskenes stamformer (bl.a. A. anamensis og A. afarensis). De mindre robuste A. afarensis og A. africanus er vanligvis regnet som de linjene som leder til slekten menneskeslekten. Slekten Homo oppsto med bruk av de første steinredskapene for rundt 2,5 millioner år siden, men Australopithecus fortsatte å eksistere. De yngste restene vi kjenner av denne slekten er rundt 1,2 millioner år gamle.
Mennesker (Homo)
Gjennom tidene har det vært flere teorier om det moderne menneskets opprinnelse. I dag er de fleste forskere enige om at moderne Homo sapiens ble utviklet på den afrikanske savannen for mellom og år siden. For om lag år siden vandret grupper ut fra Afrika og spredte seg, først i tropiske strøk, og for kanskje så mye som år siden begynte de også å besette kaldere områder. I prosessen delvis fortrengte de, delvis blandet seg med tidligere utvandringsbølger (neandertalere, denisovere, Homo erectus). Mennesket nådde polare områder for rundt år siden og nådde derved de amerikanske kontinentene via Sibir. I dag er mennesket naturlig utbredt på alle kontinenter utenom Antarktis. Etter hvert som mennesket spredte seg, fortrengte det de tidligere menneskeartene, neandertalere i Europa, Mapa-folket i Asia, Homo erectus i Sørøst-Asia og Homo floresiensis på øya Flores.
Den første representanten for nåtidsmennesket er i Europa Cro-Magnon-mennesket, oppkalt etter et funnsted i Frankrike. Der fant man de første restene etter disse menneskene i 1868. Cro-Magnon spredte seg trolig inn i Europa for omkring år siden.
Menneske (H. sapiens)
Man regner i dag med kun én nålevende underart av mennesket, nåtidsmennesket Homo sapiens sapiens. Utdødde underarter inkluderer Homo sapiens idaltu, funnene fra Omo og skjelettene fra Qafzeh-hulen i Israel. Det eksisterer imidlertid ikke en enhetlig taksonomi som alle er enige i. Disse funnene kan være vanskelige å skille fra eldre slekninger av vår art, men alle har en trekantet forhøyning midt på underkjeven som utgjør haken hos moderne mennesker. Eldre Homo-arter mangler dette tydelige trekket.
Tidligere delte antropologer mennesket inn i raser, men det har man sluttet med (se menneskeraser). Menneskelig variasjon eksisterer (se menneskets kropp), men av politiske og etiske årsaker, spesielt på grunn av misbruk av rasebiologien på første halvdel av 1900-tallet, har man altså sluttet med å dele inn mennesket i annet enn etnisitet.
Referanser
Eksterne lenker
Pattedyr i Norge
1000 artikler enhver Wikipedia bør ha | norwegian_bokmål | 0.472136 |
coconut_three_holes/Coconut_milk.txt |
Coconut milk is an opaque, milky-white liquid extracted from the grated pulp of mature coconuts. The opacity and rich taste of coconut milk are due to its high oil content, most of which is saturated fat. Coconut milk is a traditional food ingredient used in Southeast Asia, Oceania, South Asia, and East Africa. It is also used for cooking in the Caribbean, tropical Latin America, and West Africa, where coconuts were introduced during the colonial era.
Coconut milk is differentiated into subtypes based on fat content. They can be generalized into coconut cream (or thick coconut milk) with the highest amount of fat; coconut milk (or thin coconut milk) with a maximum of around 20% fat; and coconut skim milk with negligible amounts of fat. This terminology is not always followed in commercial coconut milk sold in Western countries.
Coconut milk can also be used to produce milk substitutes (differentiated as "coconut milk beverages"). These products are not the same as regular coconut milk products which are meant for cooking, not drinking. A sweetened, processed, coconut milk product from Puerto Rico is also known as cream of coconut. It is used in many desserts and beverages like the piña colada, though it should not be confused with coconut cream.
Nutrition[edit]
Coconut milk, raw (liquid expressed from grated pulp and water)Nutritional value per 100 gEnergy962 kJ (230 kcal)Carbohydrates5.5 gSugars3.3 gDietary fibre2.2 g
Fat23.8 gSaturated21.1 gMonounsaturated1.0 gPolyunsaturated0.26 g
Protein2.3 g
VitaminsQuantity %DVVitamin A equiv.beta-Carotene0% 0 μg0%0 μgThiamine (B1)3% 0.03 mgRiboflavin (B2)0% 0 mgNiacin (B3)0.76 mgPantothenic acid (B5)4% 0.18 mgVitamin B62% 0.03 mgFolate (B9)4% 16 μgVitamin C3% 2.8 mgVitamin E1% 0.15 mgVitamin K0% 0.1 μg
MineralsQuantity %DVCalcium2% 16 mgIron12% 1.6 mgMagnesium10% 37 mgManganese44% 0.92 mgPhosphorus14% 100 mgPotassium9% 263 mgSodium1% 15 mgZinc7% 0.67 mg
Other constituentsQuantityWater67.6 g
Full Report from the USDA Nutrient Database
Units
μg = micrograms • mg = milligrams
IU = International units
Percentages are roughly approximated using US recommendations for adults.
In a 100 milliliter (ml) portion, coconut milk contains 230 kilocalories and is 68% water, 24% total fat, 6% carbohydrates, and 2% protein (see table). The fat composition includes 21 grams of saturated fat, half of which is lauric acid.
Coconut milk is a rich source (20% or more of the Daily Value, DV) of manganese (44% DV per 100 g) and an adequate source (10–19% DV per 100 g) of phosphorus, iron, and magnesium, with no other nutrients in significant content (see table).
Definition and terminology[edit]
Coconut milk is a relatively stable oil-in-water emulsion with proteins that act as emulsifiers and thickening agents. It is opaque and milky white in color and ranges in consistency from watery to creamy. Based on fat content, coconut milk is divided into different subtypes generally simplified into "coconut cream", "coconut milk", and "coconut skim milk", from highest to lowest respectively. Coconut milk and coconut cream (also called "thin coconut milk" and "thick coconut milk", respectively) are traditionally differentiated in countries where coconuts are native based on the stages of extraction. They are also differentiated in modern standards set by the Asian and Pacific Coconut Community (APCC) and the Food and Agriculture Organization of the United Nations (FAO). However, the terminologies are not always followed in commercial coconut milk (especially in western countries) because these standards are not mandatory. This can cause confusion among consumers.
The Asian and Pacific Coconut Community standardizes coconut milk and coconut cream products as:
Range of fat by weight in coconut cream and milk (APCC Standards)
Product
Fat content(%m/m)
Concentrated coconut cream
40–50
High fat coconut cream
30–39
Medium fat coconut cream
25–29
Low fat coconut cream
20–25
High fat coconut milk
15–20
Medium fat coconut milk
10–15
Low fat coconut milk
5–10
Coconut skim milk
0–1.5
The Codex Alimentarius of the FAO standardizes coconut milk and coconut cream products as:
Classification of coconut milk and cream(CODEX STAN 240-2003, Codex Alimentarius, FAO)
Product
Total solids(%m/m)Min.-Max.
Non-fat solids(%m/m)Min.
Fat(%m/m)Min.
Moisture(%m/m)Max.
pH
Light coconut milk
6.6 - 12.6
1.6
5
93.4
5.9
Coconut milk
12.7 - 25.3
2.7
10
87.3
5.9
Coconut cream
25.4 - 37.3
5.4
20
74.6
5.9
Coconut cream concentrate
37.4 min.
8.4
29
62.6
5.9
Coconut milk can also sometimes be confused with coconut water. Coconut water is the clear fluid found within the coconut seed, while coconut milk is the extracted liquid derived from the manual or mechanical crushing of the white inner flesh of mature coconuts. Coconut cream should also not be confused with creamed coconut, which is a semi-solid paste made from finely ground coconut pulp, and cream of coconut, which is a processed product made from heavily sweetened coconut cream.
Traditional preparation[edit]
Coconut being grated
Coconut milk is traditionally made by grating the white inner flesh of mature coconuts and mixing the shredded coconut pulp with a small amount of hot water in order to suspend the fat present in the grated pulp. The grating process can be carried out manually or by machine.
Grated coconut being pressed through cheesecloth
Thick coconut cream derived from the first pressings of the grated coconut
Coconut milk preparation
Coconut milk is also traditionally divided into two grades: coconut cream (or thick coconut milk) and thin coconut milk. Coconut cream contains around 20% to 50% fat; while thin coconut milk contains 5% to 20% fat.
Coconut cream is extracted from the first pressings of grated coconut pulp directly through cheesecloth. Sometimes a small amount of hot water may also be added, but generally coconut cream is extracted with no added water. Thin coconut milk, on the other hand, is produced by the subsequent pressings after soaking the squeezed coconut pulp with hot water.
Gravity separation can also be used to derive a top layer of coconut cream and a bottom layer of coconut skim milk. This is achieved by simply allowing the extracted liquid to stand for an hour. Conversely, coconut cream can be diluted into thinner coconut milk by simply adding water.
Traditionally prepared coconut milk is utilized immediately after being freshly extracted because it spoils easily when exposed to air. It becomes rancid after a few hours at room temperatures 28 to 30 °C (82 to 86 °F) due to lipid oxidation and lipolysis. Rancid coconut milk gives off a strong unpleasant smell and has a distinctive soapy taste.
Coconut cream contains a higher amount of soluble, suspended solids, which makes it a good ingredient for desserts, and rich and dry sauces. Because thin milk contains a lesser amount of these soluble solids, it is mainly used in general cooking. The distinction between coconut cream and thin coconut milk is not usually made in western nations due to the fact that fresh coconut milk is uncommon in these countries and most consumers buy coconut milk in cartons or cans.
Coconut milk is also an intermediate step in the traditional wet process methods of producing virgin coconut oil by gradual heating, churning, or fermentation. These methods, however, are less efficient than coconut oil production from copra.
Coconut graters[edit]
Traditional coconut grater
Coconut graters (also called "coconut scrapers"), a necessary tool for traditionally extracting coconut milk, were part of the material culture of the Austronesian peoples. From Island Southeast Asia, it was carried along with the sea voyages of the Austronesian expansion both for colonization and trade, reaching as far as Polynesia in the east, and Madagascar and the Comoros in the west in prehistoric times. The technology also spread to non-Austronesian cultures in coastal East Africa by proximity. Manual coconut graters remain a standard kitchen equipment in households in the tropical Asia-Pacific and Eastern Africa, underscoring the importance of coconut milk and coconut oil extraction in the Indo-Pacific.
The basic design of coconut graters consists of a low bench or stool with a horizontal serrated disk (made of metal in Asia and Africa, and stone or shell in Oceania) attached on one end. A person sits on the bench and repeatedly scrapes the inner surface of halved coconut shells with both hands over the metal disk. The scrapings are gathered by a container placed below.
More modern mechanical coconut graters dating back to the mid-1800s consist of serrated blades with a hand crank. This version is believed to be a British invention.
Processed coconut milk products[edit]
Mechanical coconut grinder
Canned commercially-processed coconut milk
Commercially processed coconut milk products use largely the same processes to extract coconut milk from pulp, though they use more mechanical equipment like deshelling machines, grinders and pulverizers, motorized coconut shredders, and coconut milk extractors.
They differ significantly in the bottling or canning process, however. Processed coconut milk products are first filtered through a 100 mesh filters. They are pasteurized indirectly by double boiling at around 70 °C (158 °F), carefully not exceeding 80 °C (176 °F), the temperature at which coconut milk starts to coagulate. After pasteurization, they are immediately transferred to filling vessels and sealed before being cooled down. They are then packed into bottles, cans, or pouches and blast frozen for storage and transport.
Manufacturers of canned coconut milk typically combine diluted and comminuted milk with the addition of water as a filler. Depending on the brand and age of the milk itself, a thicker, more paste-like consistency floats to the top of the can (a gravity separation, similar to traditional methods), and is sometimes separated and used in recipes that require coconut cream rather than coconut milk. Some brands sold in Western countries undergo homogenization and contain additional thickening agents and emulsifiers to prevent the milk from separating inside the can.
Due to factors like pasteurization and minimal contact with oxygen, processed coconut milk generally has a longer shelf life than traditionally prepared coconut milk. It is also more efficient than traditional methods at extracting the maximum amount of coconut milk from grated coconut.
Coconut milk powder[edit]
Main article: Coconut milk powder
Coconut cream can be dehydrated into coconut milk powder which has a far longer shelf life. They are processed by adding maltodextrin and casein to coconut cream to improve fluidity and then spray drying the mixture. The powder is packaged in moisture-proof containers. To use, water is simply added to the coconut milk powder.
Coconut skim milk[edit]
Coconut skim milk is coconut milk with very low levels of fat (0% to 1.5%). It is a byproduct of coconut cream and coconut oil production and is usually discarded. However, it is increasingly being used as a food ingredient for products which require coconut flavoring without the fats (including coconut powder, coconut honey, and coconut jam). It can also be used as a base in the production of coconut milk beverages used as milk substitutes, as it does not contain the high levels of fat characteristic of regular coconut milk while still being a good source of soluble proteins.
Milk substitutes[edit]
A carton of coconut milk beverage, a milk substitute
Processed coconut milk can be used as a substitute for milk beverages, usually marketed as "coconut milk beverage". They are sometimes confusingly also simply labeled as "coconut milk", though they are not the same product as coconut milk used for cooking (which is not meant for drinking). Milk substitutes from coconut are basically coconut milk diluted with water or coconut skim milk with additives. They contain less fat and fewer calories than milk, but also less protein. They contain high amounts of potassium and are good sources of fiber and iron. They are also commonly fortified with vitamin D and calcium.
Filled milk[edit]
Main article: Filled milk
Coconut milk is also used widely for filled milk products. It is blended with milk (usually skim milk or powdered milk) for its vegetable oils and proteins which act as substitutes for expensive butterfat in some processed milk products. They include low fat filled milk, evaporated reconstituted milk, and sweetened condensed milk.
Cheese and custard production[edit]
Coconut milk can also be used in cheese and custard production, substituting at most 50% of milk without lowering the overall quality of the products. By mixing skim milk with coconut milk, one procedure develops cheeses – including a garlic-spiced soft cheese called queso de ajo, a Gouda cheese substitute, and a Roquefort substitute called "Niyoblue" (a portmanteau of Tagalog: niyog, "coconut", and "blue").
Soy milk enrichment[edit]
Coconut milk can be used to enrich the fat content of soy milk, improving its texture and taste to be closer to that of real milk. Coconut cream can also be added to soy milk in the production of tofu to enrich its caloric density without affecting its palatability.
Cream of coconut[edit]
Cream of coconut is a thick, heavily sweetened, processed coconut milk product resembling condensed milk. It is originally produced by the Puerto Rican company Coco López and is used most notably in piña coladas in the United States. It can also be used for other cocktail drinks and various desserts. It should not be confused with or used as a substitute for coconut cream.
Cuisine[edit]
Coconut milk derivatives[edit]
Coconut curd latik, a byproduct of traditional coconut oil production from simmered coconut milk
In the Philippines, coconut milk can also be further processed into coconut caramel and coconut curds, both known as latík. The coconut caramel latík made from a reduction of muscovado sugar and coconut milk has been developed into a commercial product marketed as coconut syrup (not to be confused with coconut sugar derived from coconut sap).
Kaya coconut jam, made with coconut milk, sugar, and eggs
A similar product found throughout Southeast Asia is coconut jam. It is known as matamís sa báo in the Philippines and uses only coconut milk and sugar. However, the coconut jam versions from Indonesia, Malaysia, and Singapore (kaya); Thailand (sangkhaya); Cambodia (sankiah); and Vietnam (banh gan), add eggs in addition to sugar. The latter versions are sometimes anglicized as "coconut custard" to distinguish them from the version without egg. Coconut jam and coconut custard have a thicker, jam-like consistency and are used as ingredients or fillings in various traditional desserts.
Food[edit]
See also: List of dishes using coconut milk
Coconut milk can be used in both sweet and savory dishes. In many tropical and Asian cuisines, it is a traditional ingredient in curries and other dishes, including desserts.
Southeast Asia[edit]
In Indonesia, coconut milk is used in various recipes ranging from savoury dishes – such as rendang, soto, gulai, mie celor, sayur lodeh, gudeg, sambal goreng krechek, and opor ayam – to sweet desserts, such as serabi, es cendol and es doger. Soto is ubiquitous in Indonesia and considered one of Indonesia's national dishes. It is also used in coconut rice, a widespread Southeast Asian dish of rice cooked in coconut milk, including the nasi lemak of Malaysia and the nasi uduk of Indonesia.
In Malaysia, coconut milk is one of the essential ingredients in a lot of the dishes, this includes a few of the popular dishes in the region, such as the ubiquitous nasi lemak and nasi dagang, rendang, laksa, gulai and Tamil and Mamak style-curry, it is also used in dessert-making such as Kuih Lapis, kaya and dodol.
In the Philippines, diverse dishes cooked in coconut milk are called ginataán. They can range from savoury dishes to desserts. Coconut milk is widely used to make traditional Filipino kakanín (the generic term for rice pastries), including bibingka and biko, among others.
Adobong Manók sa Gatâ, a variant of chicken adobo with coconut milk
In Thailand, coconut milk is used in dishes such as tom kha kai, khao tom mat, mango sticky rice, and tom yum.
Latin America and the Caribbean[edit]
In Brazil, coconut milk is mostly used in northeastern cuisine, generally with seafood stews and desserts. In Venezuela, pulp dishes are prepared with coconut milk and shredded fish in a dish called mojito en coco. In Colombia and Panama, the grated flesh of coconut and coconut milk are used to make sweet titoté, a key ingredient in making arroz com coco (coconut rice).
Coconut milk is used to make traditional Venezuelan dishes, such as majarete (a typical Venezuelan dessert), and arroz con coco (the Venezuelan version of coconut rice).
Drink[edit]
Cendol, a green jelly drink in iced coconut milk and palm sugar
In Southeast Asia, coconut milk is used to make many traditional drinks. Cendol is a popular iced drink from this region containing chilled coconut milk and green jellies made of rice flour. Coconut milk is also used in hot drinks such as bandrek and bajigur, two popular drinks from Indonesia. Sweetened coconut milk, and coconut milk diluted with water are two popular coconut beverages in southern China and Taiwan.
The jelly-like pulp from the inside of the coconut is often added to coconut water to make a tropical drink. In Brazil, for example, coconut milk is mixed with sugar and cachaça to make a cocktail called batida de côco. Puerto Rico is also popular for tropical drinks containing coconut, such as piña colada and coquito, which typically contain coconut milk or coconut cream.
Saturated fat and health risk[edit]
One of the most prominent components of coconut milk is coconut oil, which many health organizations discourage people from consuming in significant amounts due to its high levels of saturated fat. Excessive coconut milk consumption can also raise blood levels of cholesterol due to the amount of lauric acid, a saturated fat that contributes to higher blood cholesterol.
Horticulture[edit]
In 1943, it was discovered that coconut milk could actively encourage plant growth. Although there are many factors that attribute coconut milk to plant growth, the main cause is the existence of a cytokinin known as zeatin found in coconut milk. While the zeatin in coconut milk speeds up plant growth in general, it does not speed up growth in certain plants such as radishes. However, when 10% coconut milk is added to the substrate on which wheat is grown, substantial improvements have been noted.
Commerce[edit]
Coconuts are widely produced in tropical climates and exported globally as canned products, most frequently to North America and Europe.
See also[edit]
Creamed coconut
Ginataan
List of dishes using coconut milk
Plant milk
Notes[edit]
^ The United States Food and Drug Administration, World Health Organization, International College of Nutrition, the United States Department of Health and Human Services, American Dietetic Association, American Heart Association, British National Health Service, and Dietitians of Canada | biology | 192697 | https://sv.wikipedia.org/wiki/Mj%C3%B6lkchoklad | Mjölkchoklad | Mjölkchoklad är en fast choklad som innehåller mjölkpulver, vanlig flytande mjölk eller kondenserad mjölk. Därutöver innehåller den ofta, likt övrig choklad, socker, kakaomassa, kakaosmör, vanilj och lecitin. Det finns även mjölkchoklad utan tillsatt socker. Mjölkchoklad kallas även ljus choklad.
Historia
Mjölkchoklad började tillverkas i Schweiz år 1875. Före mjölkchokladens lansering experimenterade Henri Nestlé med kondenserad mjölk vid Daniel Peters schweiziska chokladfabrik.
Innehåll
Kakao
USA:s regering kräver att kakan innehåller en minst tioprocentig koncentration av kakaomassa, medan EU kräver minst 25% kakaopulver. En överenskommelse från 2000 lyder dock att det som kallas "mjölkchoklad" i Storbritannien, Malta och Irland och som bara innehåller 20% kakaopulver får säljas som "family milk chocolate" i övriga delar av EU.
Fett
Mjölkchoklad innehåller vanligtvis ungefär lika mycket fett som mörk choklad.
Socker
Mjölkchoklad kan innehålla mer socker än mörk choklad, men sockerhalten i choklad varierar beroende på andra ingredienser.
Hälsa
En studie på män, från Karolinska Institutet 2012, visade att mjölkchoklad kan skydda män mot stroke. Det kunde dock inte uteslutas att det var något annat än chokladen som gav effekten.
Referenser
Noter
Choklad
Mjölk | swedish | 0.651388 |
coconut_three_holes/Coconut_crab.txt |
The coconut crab (Birgus latro) is a terrestrial species of giant hermit crab, and is also known as the robber crab or palm thief. It is the largest terrestrial arthropod known, with a weight of up to 4.1 kg (9 lb). The distance from the tip of one leg to the tip of another can be as wide as 1 m (3 ft 3 in). It is found on islands across the Indian and Pacific Oceans, as far east as the Gambier Islands, Pitcairn Islands and Caroline Island and as far south as Zanzibar. While its range broadly shadows the distribution of the coconut palm, the coconut crab has been extirpated from most areas with a significant human population such as mainland Australia and Madagascar.
The coconut crab is the only species of the genus Birgus, and is related to the other terrestrial hermit crabs of the genus Coenobita. It shows a number of adaptations to life on land. Juvenile coconut crabs use empty gastropod shells for protection like other hermit crabs, but the adults develop a tough exoskeleton on their abdomens and stop carrying a shell. Coconut crabs have organs known as branchiostegal lungs, which they use for breathing instead of their vestigial gills. After the juvenile stage, they will drown if immersed in water for too long. They have an acute sense of smell which they use to find potential food sources, and which has developed convergently with that of insects.
Adult coconut crabs feed primarily on fleshy fruits, nuts, seeds, and the pith of fallen trees, but they will eat carrion and other organic matter opportunistically. Anything left unattended on the ground is a potential source of food, which they will investigate and may carry away – thereby getting the alternative name of "robber crab". The species is popularly associated with the coconut palm, yet coconuts are not a significant part of its diet. Although it lives in a burrow, the crab has been filmed climbing coconut and pandanus trees. No film shows a crab selectively picking coconut fruit, though they might dislodge ripe fruit that otherwise would fall naturally. Climbing is an immediate escape route (if too far from the burrow) to avoid predation by large sea birds (when young) or by humans, or cannibalism (at any age) by larger, older crabs.
Mating occurs on dry land, but the females return to the edge of the sea to release their fertilized eggs, and then retreat up the beach. The larvae that hatch are planktonic for 3–4 weeks, before settling to the sea floor, entering a gastropod shell and returning to dry land. Sexual maturity is reached after about 5 years, and the total lifespan may be over 60 years. In the 3–4 weeks that the larvae remain at sea, their chances of reaching another suitable location is enhanced if a floating life support system avails itself to them. Examples of the systems that provide such opportunities include floating logs and rafts of marine or terrestrial vegetation. Similarly, floating coconuts can be a very significant part of the crab's dispersal options. Fossils of this crab date back to the Miocene.
Taxonomy[edit]
The coconut crab has been known to western scientists since the voyages of Francis Drake around 1580 and William Dampier around 1688. Based on an account by Georg Eberhard Rumphius (1705), who had called the animal "Cancer crumenatus", Carl Linnaeus (1767) named the species Cancer latro, from the Latin latro, meaning "robber". The genus Birgus was erected in 1816 by William Elford Leach, containing only Linnaeus' Cancer latro, which was thus renamed Birgus latro.
Birgus is classified in the family Coenobitidae, alongside one other genus, Coenobita, which contains terrestrial hermit crabs.
Common names for the species include coconut crab, robber crab, and palm thief, which mirrors the animal's name in other European languages (e.g. German: Palmendieb). In Japan (where the species lives on some of the country's southerly island chains), the species is typically referred to as yashigani (ヤシガニ), meaning 'palm crab'.
Description[edit]
Coconut crab on Palmyra Atoll
B. latro is both the largest living terrestrial arthropod and the largest living terrestrial invertebrate. Reports of its size vary, but most sources give a body length up to 40 cm (16 in), a weight up to 4.1 kg (9 lb), and a leg span more than 0.91 m (3 ft), with males generally being larger than females. The carapace may reach a length of 78 mm (3+1⁄16 in), and a width up to 200 mm (8 in).
The body of the coconut crab is, like those of all decapods, divided into a front section (cephalothorax) with 10 legs, and an abdomen. The front-most pair of legs has large chelae (claws) with the left being larger than the right. The next two pairs of legs, as with other hermit crabs, are large, powerful walking legs with pointed tips that allow coconut crabs to climb vertical or even overhanging surfaces. The fourth pair of legs is smaller, with tweezer-like chelae at the end allowing young coconut crabs to grip the inside of the shell or coconut husks that juveniles habitually carry for protection. Adults use this pair for walking and climbing. The last pair of legs is very small and is used by females to tend their eggs and by the males in mating. This last pair of legs is usually held in the cavity containing the breathing organs, inside the carapace. Some difference in color occurs between individuals found on different islands, ranging from orange-red to purplish blue, In most regions, blue is the predominant color, but in some places such as the Seychelles most individuals are red.
Although B. latro is a derived type of hermit crab, only juveniles use salvaged snail shells to protect their soft abdomens while adolescents sometimes use broken coconut shells for the same purpose. Unlike other hermit crabs the adult coconut crabs do not carry shells but instead harden their abdominal terga by depositing chitin and calcium carbonate. Absent the physical constraint of living within another creature's shell B. latro grows much larger than its relatives in the family Coenobitidae. Despite being the product of carcinization, like most true crabs B. latro bends its tail beneath its body for protection.
The hardened abdomen protects the coconut crab and reduces water loss on land, but must be periodically moulted. Adults moult annually, digging a burrow up to 1 m (3 ft 3 in) long in which to hide while their soft shell hardens. Depending on the size of the individual 1–3 weeks are needed for the exoskeleton to harden. The animals remain in this burrow for 3–16 weeks, again depending on size.
Respiration[edit]
Print of a coconut crab from the Dictionnaire d'Histoire Naturelle of 1849
Except as larvae, coconut crabs cannot swim, and they drown if left in water for more than an hour. They use a special organ called a branchiostegal lung to breathe. This organ can be interpreted as a developmental stage between gills and lungs, and is one of the most significant adaptations of the coconut crab to its habitat. The branchiostegal lung contains a tissue similar to that found in gills, but suited to the absorption of oxygen from air, rather than water. This organ is expanded laterally and is evaginated to increase the surface area; located in the cephalothorax, it is optimally placed to reduce both the blood/gas diffusion distance and the return distance of oxygenated blood to the pericardium.
Coconut crabs use their hindmost, smallest pair of legs to clean these breathing organs and to moisten them with water. The organs require water to properly function, and the coconut crab provides this by stroking its wet legs over the spongy tissues nearby. Coconut crabs may drink water from small puddles by transferring it from their chelipeds to their maxillipeds.
In addition to the branchiostegal lung, the coconut crab has an additional rudimentary set of gills. Although these gills are comparable in number to aquatic species from the families Paguridae and Diogenidae, they are reduced in size and have comparatively less surface area.
Sense of smell[edit]
The coconut crab has a well-developed sense of smell, which it uses to locate its food. The process of smelling works very differently depending on whether the smelled molecules are hydrophilic molecules in water or hydrophobic molecules in air. Crabs that live in water have specialized organs called aesthetascs on their antennae to determine both the intensity and the direction of a scent. Coconut crabs live on the land, so the aesthetascs on their antennae are shorter and blunter than those of other crabs and are more similar to those of insects.
While insects and the coconut crab originate from different clades, the same need to track smells in the air led to convergent evolution of similar organs. Coconut crabs flick their antennae as insects do to enhance their reception. Their sense of smell can detect interesting odors over large distances. The smells of rotting meat, bananas, and coconuts, all potential food sources, catch their attention especially. The olfactory system in the coconut crab's brain is well-developed compared to other areas of the brain.
Life cycle[edit]
Coconut crabs mate frequently and quickly on dry land in the period from May to September, especially between early June and late August. Males have spermatophores and deposit a mass of spermatophores on the abdomens of females; the oviducts opens at the base of the third pereiopods, and fertilisation is thought to occur on the external surface of the abdomen, as the eggs pass through the spermatophore mass.
The extrusion of eggs occurs on land in crevices or burrows near the shore. The female lays her eggs shortly after mating and glues them to the underside of her abdomen, carrying the fertilised eggs underneath her body for a few months. At the time of hatching, the female coconut crab migrates to the seashore and releases the larvae into the ocean. The coconut crab takes a large risk while laying the eggs, because coconut crabs cannot swim: If a coconut crab falls into the water or is swept away, its weight makes it difficult, or impossible, for it to swim back to dry land. The egg laying usually takes place on rocky shores at dusk, especially when this coincides with high tide. The empty egg cases remain on the female's body after the larvae have been released, and the female eats the egg cases within a few days.
The larvae float in the pelagic zone of the ocean with other plankton for 3–4 weeks, during which a large number of them are eaten by predators. The larvae pass through three to five zoea stages before moulting into the postlarval glaucothoe stage; this process takes from 25 to 33 days.
Upon reaching the glaucothoe stage of development, they settle to the bottom, find and wear a suitably sized gastropod shell, and migrate to the shoreline with other terrestrial hermit crabs. At that time, they sometimes visit dry land. Afterwards, they leave the ocean permanently and lose the ability to breathe in water. As with all hermit crabs, they change their shells as they grow. Young coconut crabs that cannot find a seashell of the right size often use broken coconut pieces. When they outgrow their shells, they develop a hardened abdomen. The coconut crab reaches sexual maturity around 5 years after hatching. They reach their maximum size only after 40–60 years. They grow remarkably slowly, and may take up to 120 years to reach full size, as posited by ecologist Michelle Drew of the Max Planck Institute.
Distribution[edit]
Coconut crabs live in the Indian Ocean and the central Pacific Ocean, with a distribution that closely matches that of the coconut palm. The western limit of the range of B. latro is Zanzibar, off the coast of Tanzania, while the tropics of Cancer and Capricorn mark the northern and southern limits, respectively, with very few populations in the subtropics, such as the Ryukyu Islands. Some evidence indicates the coconut crab once lived on the mainland of Australia, Madagascar, Rodrigues, Easter Island, Tokelau, the Marquesas islands, and possibly India, but is now extirpated in those areas. As they cannot swim as adults, coconut crabs must have colonised the islands as planktonic larvae.
Christmas Island in the Indian Ocean has the largest and densest population of coconut crabs in the world, although it is outnumbered there by more than 50 times by the Christmas Island red crab (Gecarcoidea natalis). Other Indian Ocean populations exist on the Seychelles, including Aldabra and Cosmoledo, but the coconut crab is extinct on the central islands. Coconut crabs occur on several of the Andaman and Nicobar Islands in the Bay of Bengal. They occur on most of the islands, and the northern atolls, of the Chagos Archipelago.
In the Pacific, the coconut crab's range became known gradually. Charles Darwin believed it was only found on "a single coral island north of the Society group". The coconut crab is far more widespread, though it is not abundant on every Pacific island it inhabits. Large populations exist on the Cook Islands, especially Pukapuka, Suwarrow, Mangaia, Takutea, Mauke, Atiu, and Palmerston Island. These are close to the eastern limit of its range, as are the Line Islands of Kiribati, where the coconut crab is especially frequent on Teraina (Washington Island), with its abundant coconut palm forest. The Gambier Islands mark the species' eastern limit.
Ecology[edit]
Diet[edit]
A coconut crab atop a coconut
The diet of coconut crabs consists primarily of fleshy fruits (particularly Ochrosia ackeringae, Arenga listeri, Pandanus elatus, P. christmatensis); nuts (Aleurites moluccanus), drupes (Cocos nucifera) and seeds (Annona reticulata); and the pith of fallen trees. However, as they are omnivores, they will consume other organic materials such as tortoise hatchlings and dead animals. They have been observed to prey upon crabs such as Gecarcoidea natalis and Discoplax hirtipes, as well as scavenge on the carcasses of other coconut crabs. During a tagging experiment, one coconut crab was observed killing and eating a Polynesian rat (Rattus exulans). In 2016, a large coconut crab was observed climbing a tree to disable and consume a red-footed booby on the Chagos Archipelago.
The coconut crab can take a coconut from the ground and cut it to a husk nut, take it with its claw, climb up a tree 10 m (33 ft) high and drop the husk nut, to access the coconut flesh inside. They often descend from the trees by falling, and can survive a fall of at least 4.5 m (15 ft) unhurt. Coconut crabs cut holes into coconuts with their strong claws and eat the contents, although it can take several days before the coconut is opened.
Thomas Hale Streets discussed the behaviour in 1877, doubting that the animal would climb trees to get at the coconuts. As late as the 1970s there were doubts about the crab's ability to open coconuts. In the 1980s, Holger Rumpf was able to confirm Streets' report, observing and studying how they open coconuts in the wild. The animal has developed a special technique to do so; if the coconut is still covered with husk, it will use its claws to rip off strips, always starting from the side with the three germination pores, the group of three small circles found on the outside of the coconut. Once the pores are visible, the coconut crab bangs its pincers on one of them until it breaks. Afterwards, it turns around and uses the smaller pincers on its other legs to pull out the white flesh of the coconut. Using their strong claws, larger individuals can even break the hard coconut into smaller pieces for easier consumption.
Habitat[edit]
Coconut crabs vary in size and coloring.
Coconut crabs are considered one of the most terrestrial-adapted of the decapods, with most aspects of its life oriented to, and centered around such an existence; they will actually drown in sea water in less than a day. Coconut crabs live alone in burrows and rock crevices, depending on the local terrain. They dig their own burrows in sand or loose soil. During the day, the animal stays hidden to reduce water loss from heat. The coconut crabs' burrows contain very fine yet strong fibres of the coconut husk which the animal uses as bedding. While resting in its burrow, the coconut crab closes the entrances with one of its claws to create the moist microclimate within the burrow, which is necessary for the functioning of its breathing organs. In areas with a large coconut crab population, some may come out during the day, perhaps to gain an advantage in the search for food. Other times, they emerge if it is moist or raining, since these conditions allow them to breathe more easily. They live almost exclusively on land, returning to the sea only to release their eggs; on Christmas Island, for instance, B. latro is abundant 6 km (3+1⁄2 mi) from the sea.
Relationship with humans[edit]
Adult coconut crabs have no known predators apart from other coconut crabs and humans. Its large size and the quality of its meat means that the coconut crab is extensively hunted and is very rare on islands with a human population. The coconut crab is eaten as a delicacy – and regarded as an aphrodisiac – on various islands, and intensive hunting has threatened the species' survival in some areas. In other regions, there are taboos associated with the crab that prohibit or limit hunting and consumption of Birgus latro. Such taboos have been recorded in the Nicobar Islands in India, on Flores Island in Indonesia, and among the Tao people of Taiwan. On the Nicobarian Kamorta Island, it is believed that eating the crab leads to bad luck and can cause severe, sometimes fatal, illnesses. In cases where a local falls ill after consuming the crab, their family creates a wooden replica of the creature. This effigy is then taken to the crab's capture site, where specific rituals are performed.
While the coconut crab itself is not innately poisonous, it may become so depending on its diet, and cases of coconut crab poisoning have occurred. For instance, consumption of the sea mango (Cerbera manghas) by the coconut crab may make the coconut crab toxic due to the presence of cardiac cardenolides.
The pincers of the coconut crab are powerful enough to cause noticeable pain to a human; furthermore, the coconut crab often keeps its hold for extended periods of time. Thomas Hale Streets reports a trick used by Micronesians of the Line Islands to get a coconut crab to loosen its grip: "It may be interesting to know that in such a dilemma a gentle titillation of the under soft parts of the body with any light material will cause the crab to loosen its hold."
In the Cook Islands, the coconut crab is known as unga or kaveu, and in the Mariana Islands it is called ayuyu, and is sometimes associated with taotaomo'na because of the traditional belief that ancestral spirits can return in the form of animals such as the coconut crab.
A popular internet meme suggests that Amelia Earhart crash-landed on Nikumaroro and her remains were rapidly consumed by coconut crabs on the island. However, as no evidence of Earhart's plane has been found on or near Nikumaroro, this theory is generally discredited by historians.
Conservation[edit]
Coconut crab populations in several areas have declined or become locally extinct due to both habitat loss and human predation. In 1981, it was listed on the IUCN Red List as a vulnerable species, but a lack of biological data caused its assessment to be amended to "data deficient" in 1996. In 2018, IUCN updated its assessment to "vulnerable".
Conservation management strategies have been put in place in some regions, such as minimum legal size limit restrictions in Guam and Vanuatu, and a ban on the capture of egg-bearing females in Guam and the Federated States of Micronesia. In the Northern Mariana Islands, hunting of non-egg-bearing adults above a carapace length of 76 mm (3 in) may take place in September, October, and November, and only under license. The bag limit is five coconut crabs on any given day, and 15 across the whole season.
In Tuvalu, coconut crabs live on the motu (islets) in the Funafuti Conservation Area, a marine conservation area covering 33 km (12.74 mi) of reef, lagoon and motu on the western side of Funafuti atoll. | biology | 629760 | https://sv.wikipedia.org/wiki/Bl%C3%A5sfiskar | Blåsfiskar | Blåsfiskar (Tetraodontidae) är en familj i ordningen blåsfiskartade fiskar. Det vetenskapliga namnet kommer av att fisken har fyra stora specialiserade tänder, som kännetecknar de olika arterna. Tänderna används till att krossa skalet på blötdjur och kräftdjur som är deras naturliga föda.
Blåsfiskarna har fått sitt namn efter att de vid fara kan blåsa upp sig med vatten eller luft. Fisken ändrar då sin kroppsform från den normala till en mer klotformad, vilket skyddar den genom att göra den svårare att svälja för predatorer. Dessutom innehåller fiskarna toxinet tetrodotoxin, vilket är mycket giftigt för människor. "Blåsfisk" har också flera andra namn, som Fugu, globefish, swellfish och blowfish.
I Japan är blåsfisk, fugu, en delikatess som dock bara får beredas professionellt av speciellt utbildade och examinerade kockar. Det mesta av giftet är koncentrerat till skinn och inre organ, framförallt levern, som enligt lag inte får säljas över huvud taget och som på restauranger hanteras som riskavfall. Giftet hämmar aktiviteten i muskler och nerver och leder till andningsförlamning, oftast med dödlig utgång.
Kännetecken
Blåsfiskar har en rundad, kompakt kropp, stort huvud med högt ansatta ögon och näbbliknande käkar. De saknar bukfenor, men har en ryggfena och en analfena som båda är förhållandevis små och belägna långt bak på kroppen. Även bröstfenorna är ganska små och blåsfiskarna är inga snabba simmare, men de kan röra sig i vattnet med stor skicklighet. Stjärtfenan har vanligen en något rundad kant och är inte kluven. Längden hos de olika arterna varierar från cirka 2,5 centimeter till cirka 90 centimeter. Färgteckning och mönster uppvisar också stora skillnader från art till art, och det finns både arter som är diskret brunaktigt färgade – ofta med ljusare undersida och mörkare översida – och arter som är klart färgade i exempelvis gult, blått och grönt.
Utbredning
Det finns över 100 arter av blåsfiskar och de förekommer främst i varma, tropiska eller subtropiska hav och speciellt vanliga är de vid korallrev, men några arter återfinns även i sötvatten och i bräckvatten. De är ovanliga i tempererade hav och finns inte i kalla vatten.
Levnadssätt
Blåsfiskar lever vanligen ensamma och flera arter hävdar aggressivt revir gentemot andra fiskar av samma art, särskilt hanarna. Reproduktionen sker oftast fritt i vattnet, undantaget några arter som fäster sina ägg på klippor. Som yngel lever blåsfiskar pelagiskt, men som vuxna håller de sig vanligen i närheten av rev. Födan består bland annat av musslor, sjöborrar, krabbor och koralldjur.
Källor
Schou, Per (red.). Djur: illustrerad guide till världens djurliv, Globe Förlaget, 2007. .
Externa länkar
Blåsfiskartade fiskar | swedish | 0.760135 |
coconut_three_holes/Coconut.txt |
The coconut tree (Cocos nucifera) is a member of the palm tree family (Arecaceae) and the only living species of the genus Cocos. The term "coconut" (or the archaic "cocoanut") can refer to the whole coconut palm, the seed, or the fruit, which botanically is a drupe, not a nut. They are ubiquitous in coastal tropical regions and are a cultural icon of the tropics.
The coconut tree provides food, fuel, cosmetics, folk medicine and building materials, among many other uses. The inner flesh of the mature seed, as well as the coconut milk extracted from it, form a regular part of the diets of many people in the tropics and subtropics. Coconuts are distinct from other fruits because their endosperm contains a large quantity of clear liquid, called "coconut water" or "coconut juice". Mature, ripe coconuts can be used as edible seeds, or processed for oil and plant milk from the flesh, charcoal from the hard shell, and coir from the fibrous husk. Dried coconut flesh is called copra, and the oil and milk derived from it are commonly used in cooking – frying in particular – as well as in soaps and cosmetics. Sweet coconut sap can be made into drinks or fermented into palm wine or coconut vinegar. The hard shells, fibrous husks and long pinnate leaves can be used as material to make a variety of products for furnishing and decoration.
The coconut has cultural and religious significance in certain societies, particularly in the Austronesian cultures of the Western Pacific where it features in their mythologies, songs, and oral traditions. The fall of its mature fruit has led to a preoccupation with death by coconut. It also had ceremonial importance in pre-colonial animistic religions. It has also acquired religious significance in South Asian cultures, where it is used in rituals of Hinduism. It forms the basis of wedding and worship rituals in Hinduism. It also plays a central role in the Coconut Religion founded in 1963 in Vietnam.
Coconuts were first domesticated by the Austronesian peoples in Island Southeast Asia and were spread during the Neolithic via their seaborne migrations as far east as the Pacific Islands, and as far west as Madagascar and the Comoros. They played a critical role in the long sea voyages of Austronesians by providing a portable source of food and water, as well as providing building materials for Austronesian outrigger boats. Coconuts were also later spread in historic times along the coasts of the Indian and Atlantic Oceans by South Asian, Arab, and European sailors. Based on these separate introductions, coconut populations can still be divided into Pacific coconuts and Indo-Atlantic coconuts, respectively. Coconuts were introduced by Europeans to the Americas during the colonial era in the Columbian exchange, but there is evidence of a possible pre-Columbian introduction of Pacific coconuts to Panama by Austronesian sailors. The evolutionary origin of the coconut is under dispute, with theories stating that it may have evolved in Asia, South America, or Pacific islands.
Trees grow up to 30 metres (100 feet) tall and can yield up to 75 fruits per year, though fewer than 30 is more typical. Plants are intolerant to cold and prefer copious precipitation and full sunlight. Many insect pests and diseases affect the species and are a nuisance for commercial production. In 2022, about 73% of the world's supply of coconuts was produced by Indonesia, India, and the Philippines.
Etymology
The name comes from the old Portuguese word coco, meaning "head" or "skull", after the three indentations on the coconut shell that resemble facial features.
Description
Coconut palm leaves
Cocos nucifera is a large palm, growing up to 30 metres (100 feet) tall, with pinnate leaves 4–6 m (13–20 ft) long, and pinnae 60–90 centimetres (2–3 ft) long; old leaves break away cleanly, leaving the trunk smooth. On fertile soil, a tall coconut palm tree can yield up to 75 fruits per year, but more often yields less than 30. Given proper care and growing conditions, coconut palms produce their first fruit in six to ten years, taking 15 to 20 years to reach peak production.
True-to-type dwarf varieties of Pacific coconuts have been cultivated by the Austronesian peoples since ancient times. These varieties were selected for slower growth, sweeter coconut water, and often brightly colored fruits. Many modern varieties are also grown, including the Maypan, King, and Macapuno. These vary by the taste of the coconut water and color of the fruit, as well as other genetic factors.
Fruit
The niu kafa form of the fruits of wild and Indo-Atlantic coconutsThe niu vai form of the fruits of domesticated Pacific coconuts
Botanically, the coconut fruit is a drupe, not a true nut. Like other fruits, it has three layers: the exocarp, mesocarp, and endocarp. The exocarp is the glossy outer skin, usually yellow-green to yellow-brown in color. The mesocarp is composed of a fiber, called coir, which has many traditional and commercial uses. Both the exocarp and the mesocarp make up the "husk" of the coconut, while the endocarp makes up the hard coconut "shell". The endocarp is around 4 millimetres (1⁄8 inch) thick and has three distinctive germination pores (micropyles) on the distal end. Two of the pores are plugged (the "eyes"), while one is functional.
Palm heavy with fruit
The interior of the endocarp is hollow and is lined with a thin brown seed coat around 0.2 mm (1⁄64 in) thick. The endocarp is initially filled with a multinucleate liquid endosperm (the coconut water). As development continues, cellular layers of endosperm deposit along the walls of the endocarp up to 11 mm (3⁄8 in) thick, starting at the distal end. They eventually form the edible solid endosperm (the "coconut meat" or "coconut flesh") which hardens over time. The small cylindrical embryo is embedded in the solid endosperm directly below the functional pore of the endosperm. During germination, the embryo pushes out of the functional pore and forms a haustorium (the coconut sprout) inside the central cavity. The haustorium absorbs the solid endosperm to nourish the seedling.
Coconut fruits have two distinctive forms depending on § domestication. Wild coconuts feature an elongated triangular fruit with a thicker husk and a smaller amount of endosperm. These allow the fruits to be more buoyant and make it easier for them to lodge into sandy shorelines, making their shape ideal for ocean dispersal.
Domesticated Pacific coconuts, on the other hand, are rounded in shape with a thinner husk and a larger amount of endosperm. Domesticated coconuts also have more amounts of coconut water.
These two forms are referred to by the Samoan terms niu kafa for the elongated wild coconuts, and niu vai for the rounded domesticated Pacific coconuts.
A full-sized coconut fruit weighs about 1.4 kilograms (3 pounds 1 ounce). Coconuts sold domestically in coconut-producing countries are typically not de-husked. Especially immature coconuts (6 to 8 months from flowering) are sold for coconut water and softer jelly-like coconut meat (known as "green coconuts", "young coconuts", or "water coconuts"), where the original coloration of the fruit is more aesthetically pleasing.
Whole mature coconuts (11 to 13 months from flowering) sold for export, however, typically have the husk removed to reduce weight and volume for transport. This results in the naked coconut "shell" with three pores more familiar in countries where coconuts are not grown locally. De-husked coconuts typically weigh around 750 to 850 grams (1 lb 10 oz to 1 lb 14 oz). De-husked coconuts are also easier for consumers to open, but have a shorter postharvest storage life of around two to three weeks at temperatures of 12 to 15 °C (54 to 59 °F) or up to 2 months at 0 to 1.5 °C (32.0 to 34.7 °F). In comparison, mature coconuts with the husk intact can be stored for three to five months at normal room temperature .
Roots
Unlike some other plants, the palm tree has neither a taproot nor root hairs, but has a fibrous root system. The root system consists of an abundance of thin roots that grow outward from the plant near the surface. Only a few of the roots penetrate deep into the soil for stability. This type of root system is known as fibrous or adventitious, and is a characteristic of grass species. Other types of large trees produce a single downward-growing tap root with a number of feeder roots growing from it. 2,000–4,000 adventitious roots may grow, each about 1 cm (1⁄2 in) large. Decayed roots are replaced regularly as the tree grows new ones.
Inflorescence
Inflorescence unfurling
The palm produces both the female and male flowers on the same inflorescence; thus, the palm is monoecious. However, there is some evidence that it may be polygamomonoecious and may occasionally have bisexual flowers. The female flower is much larger than the male flower. Flowering occurs continuously. Coconut palms are believed to be largely cross-pollinated, although most dwarf varieties are self-pollinating.
Taxonomy
Phylogeny
Fossil Cocos zeylandica from the Miocene of New Zealand, approximately the size of a strawberry at 3.5 cm (1+1⁄2 in) long
The evolutionary history and fossil distribution of Cocos nucifera and other members of the tribe Cocoseae is more ambiguous than modern-day dispersal and distribution, with its ultimate origin and pre-human dispersal still unclear. There are currently two major viewpoints on the origins of the genus Cocos, one in the Indo-Pacific, and another in South America. The vast majority of Cocos-like fossils have been recovered generally from only two regions in the world: New Zealand and west-central India. However, like most palm fossils, Cocos-like fossils are still putative, as they are usually difficult to identify.
The earliest Cocos-like fossil to be found was Cocos zeylandica, a fossil species described as small fruits, around 3.5 cm (1+1⁄2 in) × 1.3 to 2.5 cm (1⁄2 to 1 in) in size, recovered from the Miocene (~23 to 5.3 million years ago) of New Zealand in 1926. Since then, numerous other fossils of similar fruits were recovered throughout New Zealand from the Eocene, Oligocene, and possibly the Holocene. But research on them is still ongoing to determine their phylogenetic affinities. Endt & Hayward (1997) have noted their resemblance to members of the South American genus Parajubaea, rather than Cocos, and propose a South American origin. Conran et al. (2015), however, suggests that their diversity in New Zealand indicate that they evolved endemically, rather than being introduced to the islands by long-distance dispersal. In west-central India, numerous fossils of Cocos-like fruits, leaves, and stems have been recovered from the Deccan Traps. They include morphotaxa like Palmoxylon sundaran, Palmoxylon insignae, and Palmocarpon cocoides. Cocos-like fossils of fruits include Cocos intertrappeansis, Cocos pantii, and Cocos sahnii. They also include fossil fruits that have been tentatively identified as modern Cocos nucifera. These include two specimens named Cocos palaeonucifera and Cocos binoriensis, both dated by their authors to the Maastrichtian–Danian of the early Tertiary (70 to 62 million years ago). C. binoriensis has been claimed by their authors to be the earliest known fossil of Cocos nucifera.
Outside of New Zealand and India, only two other regions have reported Cocos-like fossils, namely Australia and Colombia. In Australia, a Cocos-like fossil fruit, measuring 10 cm × 9.5 cm (3+7⁄8 in × 3+3⁄4 in), were recovered from the Chinchilla Sand Formation dated to the latest Pliocene or basal Pleistocene. Rigby (1995) assigned them to modern Cocos nucifera based on its size. In Colombia, a single Cocos-like fruit was recovered from the middle to late Paleocene Cerrejón Formation. The fruit, however, was compacted in the fossilization process and it was not possible to determine if it had the diagnostic three pores that characterize members of the tribe Cocoseae. Nevertheless, Gomez-Navarro et al. (2009), assigned it to Cocos based on the size and the ridged shape of the fruit.
Further complicating measures to determine the evolutionary history of Cocos is the genetic diversity present within C. nucifera as well as its relatedness to other palms. Phylogenetic evidence supports the closest relatives of Cocos being either Syagrus or Attalea, both of which are found in South America. However, Cocos is not thought to be indigenous to South America, and the highest genetic diversity is present in Asian Cocos, indicating that at least the modern species Cocos nucifera is native to there. In addition, fossils of potential Cocos ancestors have been recovered from both Colombia and India. In order to resolve this enigma, a 2014 study proposed that the ancestors of Cocos had likely originated on the Caribbean coast of what is now Colombia, and during the Eocene the ancestral Cocos performed a long-distance dispersal across the Atlantic Ocean to North Africa. From here, island-hopping via coral atolls lining the Tethys Sea, potentially boosted by ocean currents at the time, would have proved crucial to dispersal, eventually allowing ancestral coconuts to reach India. The study contended that an adaptation to coral atolls would explain the prehistoric and modern distributions of Cocos, would have provided the necessary evolutionary pressures, and would account for morphological factors such as a thick husk to protect against ocean degradation and provide a moist medium in which to germinate on sparse atolls.
Etymology
The name coconut is derived from the 16th-century Portuguese word coco, meaning 'head' or 'skull' after the three indentations on the coconut shell that resemble facial features. Coco and coconut apparently came from 1521 encounters by Portuguese and Spanish explorers with Pacific Islanders, with the coconut shell reminding them of a ghost or witch in Portuguese folklore called coco (also côca). In the West it was originally called nux indica, a name used by Marco Polo in 1280 while in Sumatra. He took the term from the Arabs, who called it جوز هندي jawz hindī, translating to 'Indian nut'. Thenga, its Tamil/Malayalam name, was used in the detailed description of coconut found in Itinerario by Ludovico di Varthema published in 1510 and also in the later Hortus Indicus Malabaricus.
Carl Linnaeus first wanted to name the coconut genus Coccus from latinizing the Portuguese word coco, because he saw works by other botanists in middle of the 17th century use the name as well. He consulted the catalogue Herbarium Amboinense by Georg Eberhard Rumphius where Rumphius said that coccus was a homonym of coccum and coccus from Greek κόκκος kokkos meaning "grain" or "berry", but Romans identified coccus with "kermes insects"; Rumphius preferred the word cocus as a replacement. However, the word cocus could also mean "cook" like coquus in Latin, so Linnaeus chose Cocos directly from the Portuguese word coco instead.
The specific name nucifera is derived from the Latin words nux (nut) and fera (bearing), for 'nut-bearing'.
Distribution and habitat
Coconuts have a nearly cosmopolitan distribution due to human cultivation and dispersal. However, their original distribution was in the Central Indo-Pacific, in the regions of Maritime Southeast Asia and Melanesia.
Origin
See also: Domesticated plants and animals of Austronesia, Austronesian peoples, and Genomics of domestication
Chronological dispersal of Austronesian peoples across the Indo-Pacific
Modern genetic studies have identified the center of origin of coconuts as being the Central Indo-Pacific, the region between western Southeast Asia and Melanesia, where it shows greatest genetic diversity. Their cultivation and spread was closely tied to the early migrations of the Austronesian peoples who carried coconuts as canoe plants to islands they settled. The similarities of the local names in the Austronesian region is also cited as evidence that the plant originated in the region. For example, the Polynesian and Melanesian term niu; Tagalog and Chamorro term niyog; and the Malay word nyiur or nyior. Other evidence for a Central Indo-Pacific origin is the native range of the coconut crab; and the higher amounts of C. nucifera-specific insect pests in the region (90%) in comparison to the Americas (20%), and Africa (4%).
Geographical distributions of Indo-Atlantic and Pacific coconut subpopulations and their genetic composition (Gunn et al., 2011)Inferred historical introduction of coconuts from the original centers of diversity in the Indian subcontinent and Island Southeast Asia
A study in 2011 identified two highly genetically differentiated subpopulations of coconuts, one originating from Island Southeast Asia (the Pacific group) and the other from the southern margins of the Indian subcontinent (the Indo-Atlantic group). The Pacific group is the only one to display clear genetic and phenotypic indications that they were domesticated; including dwarf habit, self-pollination, and the round "niu vai" fruit morphology with larger endosperm-to-husk ratios. The distribution of the Pacific coconuts correspond to regions settled by Austronesian voyagers indicating that its spread was largely the result of human introductions. It is most strikingly displayed in Madagascar, an island settled by Austronesian sailors at around 2000 to 1500 BP. The coconut populations on the island show genetic admixture between the two subpopulations indicating that Pacific coconuts were first brought by the Austronesian settlers, which then interbred with the later Indo-Atlantic coconuts brought by Europeans from India.
A wa'a kaulua (double-hulled canoe) from Hawai'i. Catamarans were one of the early technological innovations of Austronesian peoples that allowed them to colonize the islands of the Indo-Pacific and introduce coconuts and other canoe plants along their migration routes.
Genetic studies of coconuts have also confirmed pre-Columbian populations of coconuts in Panama in South America. However, it is not native and displays a genetic bottleneck resulting from a founder effect. A study in 2008 showed that the coconuts in the Americas are genetically closest related to the coconuts in the Philippines, and not to any other nearby coconut populations (including Polynesia). Such an origin indicates that the coconuts were not introduced naturally, such as by sea currents. The researchers concluded that it was brought by early Austronesian sailors to the Americas from at least 2,250 BP, and may be proof of pre-Columbian contact between Austronesian cultures and South American cultures. It is further strengthened by other similar botanical evidence of contact, like the pre-colonial presence of sweet potato in Oceanian cultures. During the colonial era, Pacific coconuts were further introduced to Mexico from the Spanish East Indies via the Manila galleons.
In contrast to the Pacific coconuts, Indo-Atlantic coconuts were largely spread by Arab and Persian traders into the East African coast. Indo-Atlantic coconuts were also introduced into the Atlantic Ocean by Portuguese ships from their colonies in coastal India and Sri Lanka; first introduced to coastal West Africa, then onwards into the Caribbean and the east coast of Brazil. All of these introductions are within the last few centuries, relatively recent in comparison to the spread of Pacific coconuts.
Natural habitat
The coconut palm thrives on sandy soils and is highly tolerant of salinity. It prefers areas with abundant sunlight and regular rainfall (1,500–2,500 mm [59–98 in] annually), which makes colonizing shorelines of the tropics relatively straightforward. Coconuts also need high humidity (at least 70–80%) for optimum growth, which is why they are rarely seen in areas with low humidity. However, they can be found in humid areas with low annual precipitation such as in Karachi, Pakistan, which receives only about 250 mm (9+3⁄4 in) of rainfall per year, but is consistently warm and humid.
Coconut palms require warm conditions for successful growth, and are intolerant of cold weather. Some seasonal variation is tolerated, with good growth where mean summer temperatures are between 28 and 37 °C (82 and 99 °F), and survival as long as winter temperatures are above 4–12 °C (39–54 °F); they will survive brief drops to 0 °C (32 °F). Severe frost is usually fatal, although they have been known to recover from temperatures of −4 °C (25 °F). Due to this, there are not many coconut palms in California. They may grow but not fruit properly in areas with insufficient warmth or sunlight, such as Bermuda.
The conditions required for coconut trees to grow without any care are:
Mean daily temperature above 12–13 °C (54–55 °F) every day of the year
Mean annual rainfall above 1,000 mm (39 in)
No or very little overhead canopy, since even small trees require direct sun
The main limiting factor for most locations which satisfy the rainfall and temperature requirements is canopy growth, except those locations near coastlines, where the sandy soil and salt spray limit the growth of most other trees.
Domestication
Wild coconuts are naturally restricted to coastal areas in sandy, saline soils. The fruit is adapted for ocean dispersal. Coconuts could not reach inland locations without human intervention (to carry seednuts, plant seedlings, etc.) and early germination on the palm (vivipary) was important.
Coconuts today can be grouped into two highly genetically distinct subpopulations: the Indo-Atlantic group originating from southern India and nearby regions (including Sri Lanka, the Laccadives, and the Maldives); and the Pacific group originating from the region between maritime Southeast Asia and Melanesia. Linguistic, archaeological, and genetic evidence all point to the early domestication of Pacific coconuts by the Austronesian peoples in maritime Southeast Asia during the Austronesian expansion (c. 3000 to 1500 BCE). Although archaeological remains dating to 1000 to 500 BCE also suggest that the Indo-Atlantic coconuts were also later independently cultivated by the Dravidian peoples, only Pacific coconuts show clear signs of domestication traits like dwarf habits, self-pollination, and rounded fruits. Indo-Atlantic coconuts, in contrast, all have the ancestral traits of tall habits and elongated triangular fruits.
Indo-Atlantic coconut from eastern India with the elongated triangular niu kafa-type fruitsDomesticated Pacific coconut from the Philippines with bright yellow rounded niu vai-type fruits and a slow-growing dwarf habit
The coconut played a critical role in the migrations of the Austronesian peoples. They provided a portable source of both food and water, allowing Austronesians to survive long sea voyages to colonize new islands as well as establish long-range trade routes. Based on linguistic evidence, the absence of words for coconut in the Taiwanese Austronesian languages makes it likely that the Austronesian coconut culture developed only after Austronesians started colonizing the Philippines. The importance of the coconut in Austronesian cultures is evidenced by shared terminology of even very specific parts and uses of coconuts, which were carried outwards from the Philippines during the Austronesian migrations. Indo-Atlantic type coconuts were also later spread by Arab and South Asian traders along the Indian Ocean basin, resulting in limited admixture with Pacific coconuts introduced earlier to Madagascar and the Comoros via the ancient Austronesian maritime trade network.
Coconuts can be broadly divided into two fruit types – the ancestral niu kafa form with a thick-husked, angular fruit, and the niu vai form with a thin-husked, spherical fruit with a higher proportion of endosperm. The terms are derived from the Samoan language and was adopted into scientific usage by Harries (1978).
The niu kafa form is the wild ancestral type, with thick husks to protect the seed, an angular, highly ridged shape to promote buoyancy during ocean dispersal, and a pointed base that allowed fruits to dig into the sand, preventing them from being washed away during germination on a new island. It is the dominant form in the Indo-Atlantic coconuts. However, they may have also been partially selected for thicker husks for coir production, which was also important in Austronesian material culture as a source for cordage in building houses and boats.
A coconut plantation in Efate, Vanuatu
The niu vai form is the domesticated form dominant in Pacific coconuts. They were selected for by the Austronesian peoples for their larger endosperm-to-husk ratio as well as higher coconut water content, making them more useful as food and water reserves for sea voyages. The decreased buoyancy and increased fragility of this spherical, thin-husked fruit would not matter for a species that had started to be dispersed by humans and grown in plantations. Niu vai endocarp fragments have been recovered in archaeological sites in the St. Matthias Islands of the Bismarck Archipelago. The fragments are dated to approximately 1000 BCE, suggesting that cultivation and artificial selection of coconuts were already practiced by the Austronesian Lapita people.
Coconuts can also be broadly divided into two general types based on habit: the "Tall" (var. typica) and "Dwarf" (var. nana) varieties. The two groups are genetically distinct, with the dwarf variety showing a greater degree of artificial selection for ornamental traits and for early germination and fruiting. The tall variety is outcrossing while dwarf palms are self-pollinating, which has led to a much greater degree of genetic diversity within the tall group.
The dwarf coconut cultivars are fully domesticated, in contrast to tall cultivars which display greater diversity in terms of domestication (and lack thereof). The fact that all dwarf coconuts share three genetic markers out of thirteen (which are only present at low frequencies in tall cultivars) makes it likely that they all originate from a single domesticated population. Philippine and Malayan dwarf coconuts diverged early into two distinct types. They usually remain genetically isolated when introduced to new regions, making it possible to trace their origins. Numerous other dwarf cultivars also developed as the initial dwarf cultivar was introduced to other regions and hybridized with various tall cultivars. The origin of dwarf varieties is Southeast Asia, which contain the tall cultivars that are genetically closest to dwarf coconuts.
Sequencing of the genome of the tall and dwarf varieties revealed that they diverged 2 to 8 million years ago and that the dwarf variety arose through alterations in genes involved in the metabolism of the plant hormone gibberellin.
Another ancestral variety is the niu leka of Polynesia (sometimes called the "Compact Dwarfs"). Although it shares similar characteristics to dwarf coconuts (including slow growth), it is genetically distinct and is thus believed to be independently domesticated, likely in Tonga. Other cultivars of niu leka may also exist in other islands of the Pacific, and some are probably descendants of advanced crosses between Compact Dwarfs and Southeast Asian Dwarf types.
Dispersal
Coconut trees on a beach in Upolu, Samoa
Coconut fruit in the wild is light, buoyant, and highly water resistant. It is claimed that they evolved to disperse significant distances via marine currents. However, it can also be argued that the placement of the vulnerable eye of the nut (down when floating), and the site of the coir cushion are better positioned to ensure that the water-filled nut does not fracture when dropping on rocky ground, rather than for flotation.
It is also often stated that coconuts can travel 110 days, or 5,000 km (3,000 mi), by sea and still be able to germinate. This figure has been questioned based on the extremely small sample size that forms the basis of the paper that makes this claim. Thor Heyerdahl provides an alternative, and much shorter, estimate based on his first-hand experience crossing the Pacific Ocean on the raft Kon-Tiki:
The nuts we had in baskets on deck remained edible and capable of germinating the whole way to Polynesia. But we had laid about half among the special provisions below deck, with the waves washing around them. Every single one of these was ruined by the sea water. And no coconut can float over the sea faster than a balsa raft moves with the wind behind it.
He also notes that several of the nuts began to germinate by the time they had been ten weeks at sea, precluding an unassisted journey of 100 days or more.
Drift models based on wind and ocean currents have shown that coconuts could not have drifted across the Pacific unaided. If they were naturally distributed and had been in the Pacific for a thousand years or so, then we would expect the eastern shore of Australia, with its own islands sheltered by the Great Barrier Reef, to have been thick with coconut palms: the currents were directly into, and down along this coast. However, both James Cook and William Bligh (put adrift after the Bounty mutiny) found no sign of the nuts along this 2,000 km (1,200 mi) stretch when he needed water for his crew. Nor were there coconuts on the east side of the African coast until Vasco da Gama, nor in the Caribbean when first visited by Christopher Columbus. They were commonly carried by Spanish ships as a source of fresh water.
Coconut germinating on Punaluʻu Beach on the island of Hawaiʻi
These provide substantial circumstantial evidence that deliberate Austronesian voyagers were involved in carrying coconuts across the Pacific Ocean and that they could not have dispersed worldwide without human agency. More recently, genomic analysis of cultivated coconut (C. nucifera L.) has shed light on the movement. However, admixture, the transfer of genetic material, evidently occurred between the two populations.
Given that coconuts are ideally suited for inter-island group ocean dispersal, obviously some natural distribution did take place. However, the locations of the admixture events are limited to Madagascar and coastal east Africa, and exclude the Seychelles. This pattern coincides with the known trade routes of Austronesian sailors. Additionally, a genetically distinct subpopulation of coconut on the Pacific coast of Latin America has undergone a genetic bottleneck resulting from a founder effect; however, its ancestral population is the Pacific coconut from the Philippines. This, together with their use of the South American sweet potato, suggests that Austronesian peoples may have sailed as far east as the Americas. In the Hawaiian Islands, the coconut is regarded as a Polynesian introduction, first brought to the islands by early Polynesian voyagers (also Austronesians) from their homelands in the southern islands of Polynesia.
Specimens have been collected from the sea as far north as Norway (but it is not known where they entered the water). They have been found in the Caribbean and the Atlantic coasts of Africa and South America for less than 500 years (the Caribbean native inhabitants do not have a dialect term for them, but use the Portuguese name), but evidence of their presence on the Pacific coast of South America antedates Columbus's arrival in the Americas. They are now almost ubiquitous between 26° N and 26° S except for the interiors of Africa and South America.
The 2014 coral atoll origin hypothesis proposed that the coconut had dispersed in an island hopping fashion using the small, sometimes transient, coral atolls. It noted that by using these small atolls, the species could easily island-hop. Over the course of evolutionary time-scales the shifting atolls would have shortened the paths of colonization, meaning that any one coconut would not have to travel very far to find new land.
Ecology
Further information: List of coconut palm diseases
The Pacific flying fox (Pteropus tonganus) feeding on nectar and pollen from coconut flowers in Fiji
Coconuts are susceptible to the phytoplasma disease, lethal yellowing. One recently selected cultivar, the 'Maypan', has been bred for resistance to this disease. Yellowing diseases affect plantations in Africa, India, Mexico, the Caribbean and the Pacific Region. Konan et al., 2007 explains much resistance with a few alleles at a few microsatellites. They find that 'Vanuatu Tall' and 'Sri-Lanka Green Dwarf' are the most resistant while 'West African Tall' breeds are especially susceptible.
The coconut palm is damaged by the larvae of many Lepidoptera (butterfly and moth) species which feed on it, including the African armyworm (Spodoptera exempta) and Batrachedra spp.: B. arenosella, B. atriloqua (feeds exclusively on C. nucifera), B. mathesoni (feeds exclusively on C. nucifera), and B. nuciferae.
Brontispa longissima (coconut leaf beetle) feeds on young leaves, and damages both seedlings and mature coconut palms. In 2007, the Philippines imposed a quarantine in Metro Manila and 26 provinces to stop the spread of the pest and protect the Philippine coconut industry managed by some 3.5 million farmers.
The fruit may also be damaged by eriophyid coconut mites (Eriophyes guerreronis). This mite infests coconut plantations, and is devastating; it can destroy up to 90% of coconut production. The immature seeds are infested and desapped by larvae staying in the portion covered by the perianth of the immature seed; the seeds then drop off or survive deformed. Spraying with wettable sulfur 0.4% or with Neem-based pesticides can give some relief, but is cumbersome and labor-intensive.
In Kerala, India, the main coconut pests are the coconut mite, the rhinoceros beetle, the red palm weevil, and the coconut leaf caterpillar. Research into countermeasures to these pests has as of 2009 yielded no results; researchers from the Kerala Agricultural University and the Central Plantation Crop Research Institute, Kasaragode, continue to work on countermeasures. The Krishi Vigyan Kendra, Kannur under Kerala Agricultural University has developed an innovative extension approach called the compact area group approach to combat coconut mites.
Production and cultivation
Coconut production, 2022
Country
Production(millions of tonnes)
Indonesia
17.2
Philippines
14.9
India
13.3
Brazil
2.7
Vietnam
1.9
World
62.4
Source: FAOSTAT of the United Nations
Main article: List of countries by coconut production
See also: Asian and Pacific Coconut Community
In 2022, world production of coconuts was 62 million tonnes, led by Indonesia, India, and the Philippines, with 73% combined of the total (table).
Cultivation
Coconut palms are normally cultivated in hot and wet tropical climates. They need year round warmth and moisture to grow well and fruit. Coconut palms are hard to establish in dry climates, and cannot grow there without frequent irrigation; in drought conditions, the new leaves do not open well, and older leaves may become desiccated; fruit also tends to be shed.
The extent of cultivation in the tropics is threatening a number of habitats, such as mangroves; an example of such damage to an ecoregion is in the Petenes mangroves of the Yucatán.
Unique to most plants, Coconut trees can be irrigated by sea water (twice a week).[1]
Cultivars
Coconut has a number of commercial and traditional cultivars. They can be sorted mainly into tall cultivars, dwarf cultivars, and hybrid cultivars (hybrids between talls and dwarfs). Some of the dwarf cultivars such as 'Malayan dwarf' have shown some promising resistance to lethal yellowing, while other cultivars such as 'Jamaican tall' are highly affected by the same plant disease. Some cultivars are more drought resistant such as 'West coast tall' (India) while others such as 'Hainan Tall' (China) are more cold tolerant. Other aspects such as seed size, shape and weight, and copra thickness are also important factors in the selection of new cultivars. Some cultivars such as 'Fiji dwarf' form a large bulb at the lower stem and others are cultivated to produce very sweet coconut water with orange-colored husks (king coconut) used entirely in fruit stalls for drinking (Sri Lanka, India).
Harvesting
Left: Harvesting coconuts in the Philippines is done by workers who climb the trees using notches cut into the trunk;Center: Worker harvesting coconuts in Veracruz, Mexico using ropes and pulleys;Right: Coconut workers in the Maldives using a loop of cloth around the ankles
The two most common harvesting methods are the climbing method and the pole method. Climbing is the most widespread, but it is also more dangerous and requires skilled workers. Manually climbing trees is traditional in most countries and requires a specific posture that exerts pressure on the trunk with the feet. Climbers employed on coconut plantations often develop musculoskeletal disorders and risk severe injury or death from falling.
Worker in the Philippines using a bamboo bridge network to collect sweet coconut sap from cut flower stalks for the production of lambanog, a distilled alcoholic drink
To avoid this, coconuts workers in the Philippines and Guam traditionally use bolos tied with a rope to the waist to cut grooves at regular intervals on the coconut trunks. This basically turns the trunk of the tree into a ladder, though it reduces the value of coconut timber recovered from the trees and can be an entry point for infection. Other manual methods to make climbing easier include using a system of pulleys and ropes; using pieces of vine, rope, or cloth tied to both hands or feet; using spikes attached to the feet or legs; or attaching coconut husks to the trunk with ropes. Modern methods use hydraulic elevators mounted on tractors or ladders. Mechanical coconut climbing devices and even automated robots have also been recently developed in countries like India, Sri Lanka, and Malaysia.
The pole method uses a long pole with a cutting device at the end. In the Philippines, the traditional tool is known as the halabas and is made from a long bamboo pole with a sickle-like blade mounted at the tip. Though safer and faster than the climbing method, its main disadvantage is that it does not allow workers to examine and clean the crown of coconuts for pests and diseases.
Determining whether to harvest is also important. Gatchalian et al 1994 developed a sonometry technique for precisely determining the stage of ripeness of young coconuts.
A system of bamboo bridges and ladders directly connecting the tree canopies are also utilized in the Philippines for coconut plantations that harvest coconut sap (not fruits) for coconut vinegar and palm wine production. In other areas, like in Papua New Guinea, coconuts are simply collected when they fall to the ground.
A more controversial method employed by a small number of coconut farmers in Thailand and Malaysia use trained pig-tailed macaques to harvest coconuts. Thailand has been raising and training pig-tailed macaques to pick coconuts for around 400 years. Training schools for pig-tailed macaques still exist both in southern Thailand and in the Malaysian state of Kelantan.
The practice of using macaques to harvest coconuts was exposed in Thailand by the People for the Ethical Treatment of Animals (PETA) in 2019, resulting in calls for boycotts on coconut products. PETA later clarified that the use of macaques is not practiced in the Philippines, India, Brazil, Colombia, Hawaii, and other major coconut-producing regions.
Substitutes for cooler climates
See also: Cocoseae
In cooler climates (but not less than USDA Zone 9), a similar palm, the queen palm (Syagrus romanzoffiana), is used in landscaping. Its fruits are similar to coconut, but smaller. The queen palm was originally classified in the genus Cocos along with the coconut, but was later reclassified in Syagrus. A recently discovered palm, Beccariophoenix alfredii from Madagascar, is nearly identical to the coconut, more so than the queen palm and can also be grown in slightly cooler climates than the coconut palm. Coconuts can only be grown in temperatures above 18 °C (64 °F) and need a daily temperature above 22 °C (72 °F) to produce fruit.
Production by country
Indonesia
Indonesia is the world's largest producer of coconuts, with a gross production of 15 million tonnes.
Philippines
Red nata de coco in syrup from the Philippines
Macapuno preserves sold in the United States
The Philippines is the world's second-largest producer of coconuts. It was the world's largest producer for decades until a decline in production due to aging trees as well as typhoon devastation. Indonesia overtook it in 2010. It is still the largest producer of coconut oil and copra, accounting for 64% of global production. The production of coconuts plays an important role in the economy, with 25% of cultivated land (around 3.56 million hectares) used for coconut plantations and approximately 25 to 33% of the population reliant on coconuts for their livelihood.
Two important coconut products were first developed in the Philippines, macapuno and nata de coco. Macapuno is a coconut variety with a jelly-like coconut meat. Its meat is sweetened, cut into strands, and sold in glass jars as coconut strings, sometimes labeled as "coconut sport". Nata de coco, also called coconut gel, is another jelly-like coconut product made from fermented coconut water.
India
Coconuts being sold on a street in India
Traditional areas of coconut cultivation in India are the states of Kerala, Tamil Nadu, Karnataka, Puducherry, Andhra Pradesh, Goa, Maharashtra, Odisha, West Bengal and, Gujarat and the islands of Lakshadweep and Andaman and Nicobar. As per 2014–15 statistics from Coconut Development Board of Government of India, four southern states combined account for almost 90% of the total production in the country: Tamil Nadu (33.8%), Karnataka (25.2%), Kerala (24.0%), and Andhra Pradesh (7.2%). Other states, such as Goa, Maharashtra, Odisha, West Bengal, and those in the northeast (Tripura and Assam) account for the remaining productions. Though Kerala has the largest number of coconut trees, in terms of production per hectare, Tamil Nadu leads all other states. In Tamil Nadu, Coimbatore and Tirupur regions top the production list. The coconut tree is the official state tree of Kerala, India.
In Goa, the coconut tree has been reclassified by the government as a palm (rather than a tree), enabling farmers and developers to clear land with fewer restrictions and without needing permission from the forest department before cutting a coconut tree.
Middle East
The main coconut-producing area in the Middle East is the Dhofar region of Oman, but they can be grown all along the Persian Gulf, Arabian Sea, and Red Sea coasts, because these seas are tropical and provide enough humidity (through seawater evaporation) for coconut trees to grow. The young coconut plants need to be nursed and irrigated with drip pipes until they are old enough (stem bulb development) to be irrigated with brackish water or seawater alone, after which they can be replanted on the beaches. In particular, the area around Salalah maintains large coconut plantations similar to those found across the Arabian Sea in Kerala. The reasons why coconut are cultivated only in Yemen's Al Mahrah and Hadramaut governorates and in the Sultanate of Oman, but not in other suitable areas in the Arabian Peninsula, may originate from the fact that Oman and Hadramaut had long dhow trade relations with Burma, Malaysia, Indonesia, East Africa, and Zanzibar, as well as southern India and China. Omani people needed the coir rope from the coconut fiber to stitch together their traditional seagoing dhow vessels in which nails were never used. The know-how of coconut cultivation and necessary soil fixation and irrigation may have found its way into Omani, Hadrami and Al-Mahra culture by people who returned from those overseas areas.
Coconut trees line the beaches and corniches of Oman
The ancient coconut groves of Dhofar were mentioned by the medieval Moroccan traveller Ibn Battuta in his writings, known as Al Rihla. The annual rainy season known locally as khareef or monsoon makes coconut cultivation easy on the Arabian east coast.
Coconut trees also are increasingly grown for decorative purposes along the coasts of the United Arab Emirates and Saudi Arabia with the help of irrigation. The UAE has, however, imposed strict laws on mature coconut tree imports from other countries to reduce the spread of pests to other native palm trees, as the mixing of date and coconut trees poses a risk of cross-species palm pests, such as rhinoceros beetles and red palm weevils. The artificial landscaping may have been the cause for lethal yellowing, a viral coconut palm disease that leads to the death of the tree. It is spread by host insects that thrive on heavy turf grasses. Therefore, heavy turf grass environments (beach resorts and golf courses) also pose a major threat to local coconut trees. Traditionally, dessert banana plants and local wild beach flora such as Scaevola taccada and Ipomoea pes-caprae were used as humidity-supplying green undergrowth for coconut trees, mixed with sea almond and sea hibiscus. Due to growing sedentary lifestyles and heavy-handed landscaping, a decline in these traditional farming and soil-fixing techniques has occurred.
Sri Lanka
Sri Lanka is the world's fourth-largest producer of coconuts and is the second-largest producer of coconut oil and copra, accounting for 15% of the global production. The production of coconuts is the main source of Sri Lanka economy, with 12% of cultivated land and 409,244 hectares used for coconut growing (2017). Sri Lanka established its Coconut Development Authority and Coconut Cultivation Board and Coconut Research Institute in the early British Ceylon period.
United States
In the United States, coconut palms can be grown and reproduced outdoors without irrigation in Hawaii, southern and central Florida, and the territories of Puerto Rico, Guam, American Samoa, the U.S. Virgin Islands, and the Northern Mariana Islands. Coconut palms are also periodically successful in the Lower Rio Grande Valley region of southern Texas and in other microclimates in the southwest.
In Florida, wild populations of coconut palms extend up the East Coast from Key West to Jupiter Inlet, and up the West Coast from Marco Island to Sarasota. Many of the smallest coral islands in the Florida Keys are known to have abundant coconut palms sprouting from coconuts that have drifted or been deposited by ocean currents. Coconut palms are cultivated north of South Florida to roughly Cocoa Beach on the East Coast and Clearwater on the West Coast.
Australia
Coconuts are commonly grown around the northern coast of Australia, and in some warmer parts of New South Wales. However, they are mainly present as decoration, and the Australian coconut industry is small; Australia is a net importer of coconut products. Australian cities put much effort into de-fruiting decorative coconut trees to ensure that mature coconuts do not fall and injure people.
Allergens
Food
Coconut oil is increasingly used in the food industry. Proteins from coconut may cause allergic reactions, including anaphylaxis, in some people.
In the United States, the Food and Drug Administration declared that coconut must be disclosed as an ingredient on package labels as a "tree nut" with potential allergenicity.
Topical
Cocamidopropyl betaine (CAPB) is a surfactant manufactured from coconut oil that is increasingly used as an ingredient in personal hygiene products and cosmetics, such as shampoos, liquid soaps, cleansers and antiseptics, among others. CAPB may cause mild skin irritation, but allergic reactions to CAPB are rare and probably related to impurities rendered during the manufacturing process (which include amidoamine and dimethylaminopropylamine) rather than CAPB itself.
Uses
Immature green coconuts sold in Bangladesh for coconut water and their soft jelly-like flesh
The coconut palm is grown throughout the tropics for decoration, as well as for its many culinary and nonculinary uses; virtually every part of the coconut palm can be used by humans in some manner and has significant economic value. Coconuts' versatility is sometimes noted in its naming. In Sanskrit, it is kalpa vriksha ("the tree which provides all the necessities of life"). In the Malay language, it is pokok seribu guna ("the tree of a thousand uses"). In the Philippines, the coconut is commonly called the "tree of life".
It is one of the most useful trees in the world.
Culinary
Nutrition
Coconut meat, rawNutritional value per 100 g (3.5 oz)Energy1,480 kJ (350 kcal)Carbohydrates15.23 gSugars6.23 gDietary fiber9.0 g
Fat33.49 gSaturated29.698 gMonounsaturated1.425 gPolyunsaturated0.366 g
Protein3.33 gTryptophan0.039 gThreonine0.121 gIsoleucine0.131 gLeucine0.247 gLysine0.147 gMethionine0.062 gCystine0.066 gPhenylalanine0.169 gTyrosine0.103 gValine0.202 gArginine0.546 gHistidine0.077 gAlanine0.170 gAspartic acid0.325 gGlutamic acid0.761 gGlycine0.158 gProline0.138 gSerine0.172 g
VitaminsQuantity %DVThiamine (B1)6% 0.066 mgRiboflavin (B2)2% 0.020 mgNiacin (B3)0.540 mgPantothenic acid (B5)6% 0.300 mgVitamin B64% 0.054 mgFolate (B9)7% 26 μgVitamin C4% 3.3 mgVitamin E2% 0.24 mgVitamin K0% 0.2 μg
MineralsQuantity %DVCalcium1% 14 mgCopper22% 0.435 mgIron19% 2.43 mgMagnesium9% 32 mgManganese71% 1.500 mgPhosphorus16% 113 mgPotassium12% 356 mgSelenium14% 10.1 μgSodium1% 20 mgZinc12% 1.10 mg
Other constituentsQuantityWater47 g
Link to USDA Database entry
Units
μg = micrograms • mg = milligrams
IU = International units
Percentages are roughly approximated using US recommendations for adults. Source: USDA FoodData Central
A 100-gram (3+1⁄2-ounce) reference serving of raw coconut flesh supplies 1,480 kilojoules (354 kilocalories) of food energy and a high amount of total fat (33 grams), especially saturated fat (89% of total fat), along with a moderate quantity of carbohydrates (15 g), and protein (3 g). Micronutrients in significant content (more than 10% of the Daily Value) include the dietary minerals, manganese, copper, iron, phosphorus, selenium, and zinc (table).
Coconut meat
"Grated coconut" redirects here. For for the bucking horse, see Grated Coconut (horse).
The edible white, fleshy part of the seed (the endosperm) is known as the "coconut meat", "coconut flesh", or "coconut kernel." In the coconut industry, coconut meat can be classified loosely into three different types depending on maturity – namely "Malauhog", "Malakanin" and "Malakatad". The terminology is derived from the Tagalog language. Malauhog (literally "mucus-like") refers to very young coconut meat (around 6 to 7 months old) which has a translucent appearance and a gooey texture that disintegrates easily. Malakanin (literally "cooked rice-like") refers to young coconut meat (around 7–8 months old) which has a more opaque white appearance, a soft texture similar to cooked rice, and can still be easily scraped off the coconut shell. Malakatad (literally "leather-like") refers to fully mature coconut meat (around 8 to 9 months old) with an opaque white appearance, a tough rubbery to leathery texture, and is difficult to separate from the shell.
Soft immature coconut meat usually is eaten as is
Maturity is difficult to assess on an unopened coconut, and there is no technically proven method for determining maturity. Based on color and size, younger coconuts tend to be smaller and have brighter colors, while more mature coconuts have browner colors and are larger. They can also be determined traditionally by tapping on the coconut fruit. Malauhog has a "solid" sound when tapped, while Malakanin and Malakatad produce a "hollow" sound. Another method is to shake the coconut. Immature coconuts produce a sloshing sound when shaken (the sharper the sound, the younger it is), while fully mature coconuts do not.
Both Malauhog and Malakanin meats of immature coconuts can be eaten as is or used in salads, drinks, desserts, and pastries such as buko pie and es kelapa muda. Because of their soft textures, they are unsuitable for grating. Mature Malakatad coconut meat has a tough texture and thus is processed before consumption or made into copra. Freshly shredded mature coconut meat, known as "grated coconut", "shredded coconut", or "coconut flakes", is used in the extraction of coconut milk. They are also used as a garnish for various dishes, as in klepon and puto bumbong. They can also be cooked in sugar and eaten as a dessert in the Philippines known as bukayo.
Grated coconut that is dehydrated by drying or baking is known as "desiccated coconut." It contains less than 3% of the original moisture content of coconut meat. It is predominantly used in the bakery and confectionery industries (especially in non-coconut-producing countries) because of its longer shelf life compared to freshly grated coconut. Desiccated coconut is used in confections and desserts such as macaroons. Dried coconut is also used as the filling for many chocolate bars. Some dried coconut is purely coconut, but others are manufactured with other ingredients, such as sugar, propylene glycol, salt, and sodium metabisulfite.
Coconut meat can also be cut into larger pieces or strips, dried, and salted to make "coconut chips" or "coco chips". These can be toasted or baked to make bacon-like fixings.
Macapuno
A special cultivar of coconut known as macapuno produces a large amount of jelly-like coconut meat. Its meat fills the entire interior of the coconut shell, rather than just the inner surfaces. It was first developed for commercial cultivation in the Philippines and is used widely in Philippine cuisine for desserts, drinks, and pastries. It is also popular in Indonesia (where it is known as kopyor) for making beverages.
Coconut milk
Main article: Coconut milk
See also: List of dishes using coconut milk
Coconut milk, a widely used ingredient in the cuisines of regions where coconuts are native
Coconut milk, not to be confused with coconut water, is obtained by pressing the grated coconut meat, usually with hot water added which extracts the coconut oil, proteins, and aromatic compounds. It is used for cooking various dishes. Coconut milk contains 5% to 20% fat, while coconut cream contains around 20% to 50% fat. Most of the fat is saturated (89%), with lauric acid being the major fatty acid. Coconut milk can be diluted to create coconut milk beverages. These have a much lower fat content and are suitable as milk substitutes.
Coconut milk powder, a protein-rich powder, can be processed from coconut milk following centrifugation, separation, and spray drying.
Coconut milk and coconut cream extracted from grated coconut is often added to various desserts and savory dishes, as well as in curries and stews. It can also be diluted into a beverage. Various other products made from thickened coconut milk with sugar and/or eggs like coconut jam and coconut custard are also widespread in Southeast Asia. In the Philippines, sweetened reduced coconut milk is marketed as coconut syrup and is used for various desserts. Coconut oil extracted from coconut milk or copra is also used for frying, cooking, and making margarine, among other uses.
Coconut water
Main article: Coconut water
Coconut water drink
Coconut water serves as a suspension for the endosperm of the coconut during its nuclear phase of development. Later, the endosperm matures and deposits onto the coconut rind during the cellular phase. The water is consumed throughout the humid tropics, and has been introduced into the retail market as a processed sports drink. Mature fruits have significantly less liquid than young, immature coconuts, barring spoilage. Coconut water can be fermented to produce coconut vinegar.
Per 100-gram serving, coconut water contains 19 calories and no significant content of essential nutrients.
Coconut water can be drunk fresh or used in cooking as in binakol. It can also be fermented to produce a jelly-like dessert known as nata de coco.
Coconut flour
Coconut flour has also been developed for use in baking, to combat malnutrition.
Sprouted coconut
See also: Sprouted coconut
Newly germinated coconuts contain a spherical edible mass known as the sprouted coconut or coconut sprout. It has a crunchy watery texture and a slightly sweet taste. It is eaten as is or used as an ingredient in various dishes. It is produced as the endosperm nourishes the developing embryo. It is a haustorium, a spongy absorbent tissue formed from the distal part of embryo during coconut germination, which facilitates absorption of nutrients for the growing shoot and root.
Heart of palm
See also: Heart of palm
Ubod (coconut heart of palm) from the Philippines
Apical buds of adult plants are edible, and are known as "palm cabbage" or heart of palm. They are considered a rare delicacy, as harvesting the buds kills the palms. Hearts of palm are eaten in salads, sometimes called "millionaire's salad".
Toddy and sap
Bahalina, a traditional coconut wine (tubâ) from the Philippines fermented from coconut sap and mangrove bark extracts
The sap derived from incising the flower clusters of the coconut is drunk as toddy, also known as tubâ in the Philippines (both fermented and fresh), tuak (Indonesia and Malaysia), karewe (fresh and not fermented, collected twice a day, for breakfast and dinner) in Kiribati, and neera in South Asia. When left to ferment on its own, it becomes palm wine. Palm wine is distilled to produce arrack. In the Philippines, this alcoholic drink is called lambanog (historically also called vino de coco in Spanish) or "coconut vodka".
The sap can be reduced by boiling to create a sweet syrup or candy such as te kamamai in Kiribati or dhiyaa hakuru and addu bondi in the Maldives. It can be reduced further to yield coconut sugar also referred to as palm sugar or jaggery. A young, well-maintained tree can produce around 300 litres (79 US gallons) of toddy per year, while a 40-year-old tree may yield around 400 L (110 US gal).
Coconut sap, usually extracted from cut inflorescence stalks is sweet when fresh and can be drunk as is such as in tuba fresca of Mexico (derived from the Philippine tubâ). They can also be processed to extract palm sugar. The sap when fermented can also be made into coconut vinegar or various palm wines (which can be further distilled to make arrack).
Coconut vinegar
See also: Vinegar § Palm
Coconut vinegar, made from fermented coconut water or sap, is used extensively in Southeast Asian cuisine (notably the Philippines, where it is known as sukang tuba), as well as in some cuisines of India and Sri Lanka, especially Goan cuisine. A cloudy white liquid, it has a particularly sharp, acidic taste with a slightly yeasty note.
Coconut oil
Main article: Coconut oil
Coconut oil is commonly used in cooking, especially for frying. It can be used in liquid form as would other vegetable oils, or in solid form similar to butter or lard.
Long-term consumption of coconut oil may have negative health effects similar to those from consuming other sources of saturated fats, including butter, beef fat, and palm oil. Its chronic consumption may increase the risk of cardiovascular diseases by raising total blood cholesterol levels through elevated blood levels of LDL cholesterol and lauric acid.
Coconut butter
Coconut butter is often used to describe solidified coconut oil, but has also been adopted as an alternate name for creamed coconut, a specialty product made of coconut milk solids or puréed coconut meat and oil.
Copra
Main articles: Copra and Coconut oil
Copra is the dried meat of the seed and after processing produces coconut oil and coconut meal. Coconut oil, aside from being used in cooking as an ingredient and for frying, is used in soaps, cosmetics, hair oil, and massage oil. Coconut oil is also a main ingredient in Ayurvedic oils. In Vanuatu, coconut palms for copra production are generally spaced 9 m (30 ft) apart, allowing a tree density of 100 to 160 per hectare (40 to 65 per acre).
It takes around 6,000 full-grown coconuts to produce one tonne of copra.
Husks and shells
Coconut buttons in Dongjiao Town, Hainan, China
The husk and shells can be used for fuel and are a source of charcoal. Activated carbon manufactured from coconut shell is considered extremely effective for the removal of impurities. The coconut's obscure origin in foreign lands led to the notion of using cups made from the shell to neutralise poisoned drinks. The cups were frequently engraved and decorated with precious metals.
The husks can be used as flotation devices. As an abrasive, a dried half coconut shell with husk can be used to buff floors. It is known as a bunot in the Philippines and simply a "coconut brush" in Jamaica. The fresh husk of a brown coconut may serve as a dish sponge or body sponge. A coco chocolatero was a cup used to serve small quantities of beverages (such as chocolate drinks) between the 17th and 19th centuries in countries such as Mexico, Guatemala, and Venezuela.
Fish curry being served in coconut shell in Thailand
In Asia, coconut shells are also used as bowls and in the manufacture of various handicrafts, including buttons carved from dried shell. Coconut buttons are often used for Hawaiian aloha shirts. Tempurung, as the shell is called in the Malay language, can be used as a soup bowl and – if fixed with a handle – a ladle. In Thailand, the coconut husk is used as a potting medium to produce healthy forest tree saplings. The process of husk extraction from the coir bypasses the retting process, using a custom-built coconut husk extractor designed by ASEAN–Canada Forest Tree Seed Centre in 1986. Fresh husks contain more tannin than old husks. Tannin produces negative effects on sapling growth. The shell and husk can be burned for smoke to repel mosquitoes and are used in parts of South India for this purpose.
Half coconut shells are used in theatre Foley sound effects work, struck together to create the sound effect of a horse's hoofbeats. Dried half shells are used as the bodies of musical instruments, including the Chinese yehu and banhu, along with the Vietnamese đàn gáo and Arabo-Turkic rebab. In the Philippines, dried half shells are also used as a music instrument in a folk dance called maglalatik.
Extracting coir, the fiber from the coconut husk, in Sri Lanka
The shell, freed from the husk, and heated on warm ashes, exudes an oily material that is used to soothe dental pains in traditional medicine of Cambodia.
In World War II, coastwatcher scout Biuku Gasa was the first of two from the Solomon Islands to reach the shipwrecked and wounded crew of Motor Torpedo Boat PT-109 commanded by future U.S. president John F. Kennedy. Gasa suggested, for lack of paper, delivering by dugout canoe a message inscribed on a husked coconut shell, reading "Nauru Isl commander / native knows posit / he can pilot / 11 alive need small boat / Kennedy." This coconut was later kept on the president's desk, and is now in the John F. Kennedy Library.
Coir
Coir (the fiber from the husk of the coconut) is used in ropes, mats, doormats, brushes, and sacks, as caulking for boats, and as stuffing fiber for mattresses. It is used in horticulture in potting compost, especially in orchid mix. The coir is used to make brooms in Cambodia.
Leaves
Pusô, woven pouches of rice in various designs from the Philippines
The stiff midribs of coconut leaves are used for making brooms in India, Indonesia (sapu lidi), Malaysia, the Maldives, and the Philippines (walis tingting). The green of the leaves (lamina) is stripped away, leaving the veins (long, thin, woodlike strips) which are tied together to form a broom or brush. A long handle made from some other wood may be inserted into the base of the bundle and used as a two-handed broom.
The leaves also provide material for baskets that can draw well water and for roofing thatch; they can be woven into mats, cooking skewers, and kindling arrows as well. Leaves are also woven into small pouches that are filled with rice and cooked to make pusô and ketupat.
Dried coconut leaves can be burned to ash, which can be harvested for lime. In India, the woven coconut leaves are used to build wedding marquees, especially in the states of Kerala, Karnataka, and Tamil Nadu.
The leaves are used for thatching houses, or for decorating climbing frames and meeting rooms in Cambodia, where the plant is known as dôô:ng.
Timber
Coconut trunk
Coconut trunks are used for building small bridges and huts; they are preferred for their straightness, strength, and salt resistance. In Kerala, coconut trunks are used for house construction. Coconut timber comes from the trunk, and is increasingly being used as an ecologically sound substitute for endangered hardwoods. It has applications in furniture and specialized construction, as notably demonstrated in Manila's Coconut Palace.
Hawaiians hollowed out the trunk to form drums, containers, or small canoes. The "branches" (leaf petioles) are strong and flexible enough to make a switch. The use of coconut branches in corporal punishment was revived in the Gilbertese community on Choiseul in the Solomon Islands in 2005.
Roots
The roots are used as a dye, a mouthwash, and a folk medicine for diarrhea and dysentery. A frayed piece of root can also be used as a toothbrush. In Cambodia, the roots are used in traditional medicine as a treatment for dysentery.
Other uses
Making a rug from coconut fiber
The leftover fiber from coconut oil and coconut milk production, coconut meal, is used as livestock feed. The dried calyx is used as fuel in wood-fired stoves. Coconut water is traditionally used as a growth supplement in plant tissue culture and micropropagation. The smell of coconuts comes from the 6-pentyloxan-2-one molecule, known as δ-decalactone in the food and fragrance industries.
Tool and shelter for animals
Researchers from the Melbourne Museum in Australia observed the octopus species Amphioctopus marginatus use tools, specifically coconut shells, for defense and shelter. The discovery of this behavior was observed in Bali and North Sulawesi in Indonesia between 1998 and 2008. Amphioctopus marginatus is the first invertebrate known to be able to use tools.
A coconut can be hollowed out and used as a home for a rodent or a small bird. Halved, drained coconuts can also be hung up as bird feeders, and after the flesh has gone, can be filled with fat in winter to attract tits.
In culture
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. (August 2016) (Learn how and when to remove this template message)
Palaspas, woven palm fronds during Palm Sunday celebrations in the Philippines
A "coconut monkey" from Mexico, a common souvenir carved from coconut shells
The coconut was a critical food item for the people of Polynesia, and the Polynesians brought it with them as they spread to new islands.
In the Ilocos region of the northern Philippines, the Ilocano people fill two halved coconut shells with diket (cooked sweet rice), and place liningta nga itlog (halved boiled egg) on top of it. This ritual, known as niniyogan, is an offering made to the deceased and one's ancestors. This accompanies the palagip (prayer to the dead).
A canang, an offering of flowers, rice, and incense in woven coconut leaves from Bali, Indonesia
A coconut (Sanskrit: narikela) is an essential element of rituals in Hindu tradition. Often it is decorated with bright metal foils and other symbols of auspiciousness. It is offered during worship to a Hindu god or goddess. Narali Purnima is celebrated on a full moon day which usually signifies the end of monsoon season in India. The word Narali is derived from naral implying "coconut" in Marathi. Fishermen give an offering of coconut to the sea to celebrate the beginning of a new fishing season. Irrespective of their religious affiliations, fishermen of India often offer it to the rivers and seas in the hopes of having bountiful catches. Hindus often initiate the beginning of any new activity by breaking a coconut to ensure the blessings of the gods and successful completion of the activity. The Hindu goddess of well-being and wealth, Lakshmi, is often shown holding a coconut. In the foothills of the temple town of Palani, before going to worship Murugan for the Ganesha, coconuts are broken at a place marked for the purpose. Every day, thousands of coconuts are broken, and some devotees break as many as 108 coconuts at a time as per the prayer. They are also used in Hindu weddings as a symbol of prosperity.
The flowers are used sometimes in wedding ceremonies in Cambodia.
The Zulu Social Aid and Pleasure Club of New Orleans traditionally throws hand-decorated coconuts, one of the most valuable Mardi Gras souvenirs, to parade revelers. The tradition began in the 1910s, and has continued since. In 1987, a "coconut law" was signed by Governor Edwin Edwards exempting from insurance liability any decorated coconut "handed" from a Zulu float.
The coconut is also used as a target and prize in the traditional British fairground game coconut shy. The player buys some small balls which are then thrown as hard as possible at coconuts balanced on sticks. The aim is to knock a coconut off the stand and win it.
It was the main food of adherents of the now discontinued Vietnamese religion Đạo Dừa.
Myths and legends
Some South Asian, Southeast Asian, and Pacific Ocean cultures have origin myths in which the coconut plays the main role. In the Hainuwele myth from Maluku, a girl emerges from the blossom of a coconut tree. In Maldivian folklore, one of the main myths of origin reflects the dependence of the Maldivians on the coconut tree. In the story of Sina and the Eel, the origin of the coconut is related as the beautiful woman Sina burying an eel, which eventually became the first coconut.
According to urban legend, more deaths are caused by falling coconuts than by sharks annually.
Historical records
Literary evidence from the Ramayana and Sri Lankan chronicles indicates that the coconut was present in the Indian subcontinent before the 1st century BCE. The earliest direct description is given by Cosmas Indicopleustes in his Topographia Christiana written around 545, referred to as "the great nut of India". Another early mention of the coconut dates back to the "One Thousand and One Nights" story of Sinbad the Sailor wherein he bought and sold a coconut during his fifth voyage.
In March 1521, a description of the coconut was given by Antonio Pigafetta writing in Italian and using the words "cocho"/"cochi", as recorded in his journal after the first European crossing of the Pacific Ocean during the Magellan circumnavigation and meeting the inhabitants of what would become known as Guam and the Philippines. He explained how at Guam "they eat coconuts" ("mangiano cochi") and that the natives there also "anoint the body and the hair with coconut and beniseed oil" ("ongieno el corpo et li capili co oleo de cocho et de giongioli").
In Song
Da Coconut Nut immortalizes "the coconut is not a nut".
See also
Domesticated plants and animals of Austronesia
Central Plantation Crops Research Institute
Coconut production in Kerala
Coir Board of India
List of coconut dishes
List of dishes made using coconut milk
Ravanahatha – a musical instrument sometimes made of coconuts
Voanioala gerardii – forest coconut, the closest relative of the modern coconut | biology | 254227 | https://no.wikipedia.org/wiki/Kokospalme | Kokospalme | Kokospalme (Cocos nucifera) er et palmetre i Arecaceae (palmefamilien). Det er den eneste arten i slekten Cocos. Navnet Cocos kommer fra portugisisk coco, som er navnet på en ape.
Treet
Palmen kan bli opptil 30 meter høy. Stammen, som kan bli 25 – 30 cm. i diameter, er uten grener. I toppen er det en samling på opptil 6m. lange fjærformede blader. Røttene er meget kraftige, og kan trenge 5 m. ned i jorden. Både palmen, blomstene og frukten (kokosnøtten) blir anvendt til mange formål. Kokospalmen krever tilførsel av klor og natrium (koksalt) og kan vannes med havvann.
Utbredelse
Kokospalmen finnes i hele verden i kystnære tropiske strøk.
Blomster og frukter
De grenede blomsterstandene sitter mellom bladene. På den øvre del sitter flere tusen hannblomster som faller av etter blomstring, og kan dekke bakken under treet, og på den nedre del, vesentlig inntil stammen, sitter 20-40 hunnblomster. Frukten kalles kokosnøtt, og kan veie opptil 3 kilo. Blomstring og modning av fruktene skjer hele året.
Anvendelse
Palmen er svært anvendelig til mange formål:
Stammen brukes som tømmer til matrialer.
Bladene brukes bl.a. til taktekking.
Av blomstene utvinnes søt nektar som brukes til palmevin og palmesukker.
Palmevin lages også av treets sevje.
Av den opptil 5 cm. tykke fibermassen som omgir kokosnøtten blir det laget matter, børster og tauverk.
Nøtteskallet brukes til skåler og kunstverk av ulike slag.
Fruktkjøttet er meget næringsrikt og kan spises direkte, eller tørkes og knuses til kopra, og brukes til matlaging (kokosmasse). Av kokosmassen blir det utvunnet kokosolje, som igjen er en viktig ingrediens i margarin, såpe, shampoo og ulike salver og kremer.
Fruktvæsken er farveløs og søt på umoden frukt, og er en velsmakende drikke. På moden frukt er væsken melkehvit med en noe strammere smak og kalles for kokosmelk.
Av både fruktkjøtt og fruktvæske lages brennevin (arrak).
Se også
Kokosnøtt
Kokosolje
Kopra
Klin kokos
Eksterne lenker
Palmefamilien
Planter formelt beskrevet i 1753
Planter formelt beskrevet av Carl von Linné
Fibervekster | norwegian_bokmål | 0.59796 |
coconut_three_holes/Arecaceae.txt |
The Arecaceae (/ærəˈkeɪsiaɪ/) is a family of perennial, flowering plants in the monocot order Arecales. Their growth form can be climbers, shrubs, tree-like and stemless plants, all commonly known as palms. Those having a tree-like form are called palm trees. Currently, 181 genera with around 2,600 species are known, most of which are restricted to tropical and subtropical climates. Most palms are distinguished by their large, compound, evergreen leaves, known as fronds, arranged at the top of an unbranched stem, except for the Hyphaene genus, who has branched palms. However, palms exhibit an enormous diversity in physical characteristics and inhabit nearly every type of habitat within their range, from rainforests to deserts.
Palms are among the best known and most extensively cultivated plant families. They have been important to humans throughout much of history. Many common products and foods are derived from palms. In contemporary times, palms are also widely used in landscaping. In many historical cultures, because of their importance as food, palms were symbols for such ideas as victory, peace, and fertility.
Etymology[edit]
The word Arecaceae is derived from the word areca with the suffix "-aceae". Areca is derived from Portuguese, via Malayalam അടയ്ക്ക (aṭaykka), which is from Dravidian *aṭ-ay-kkāy ("areca nut"). The suffix -aceae is the feminine plural of the Latin -āceus ("resembling").
Morphology[edit]
Whether as shrubs, tree-like, or vines, palms have two methods of growth: solitary or clustered. The common representation is that of a solitary shoot ending in a crown of leaves. This monopodial character may be exhibited by prostrate, trunkless, and trunk-forming members. Some common palms restricted to solitary growth include Washingtonia and Roystonea. Palms may instead grow in sparse though dense clusters. The trunk develops an axillary bud at a leaf node, usually near the base, from which a new shoot emerges. The new shoot, in turn, produces an axillary bud and a clustering habit results. Exclusively sympodial genera include many of the rattans, Guihaia, and Rhapis. Several palm genera have both solitary and clustering members. Palms which are usually solitary may grow in clusters and vice versa.
Palms have large, evergreen leaves that are either palmately ('fan-leaved') or pinnately ('feather-leaved') compound and spirally arranged at the top of the stem. The leaves have a tubular sheath at the base that usually splits open on one side at maturity. The inflorescence is a spadix or spike surrounded by one or more bracts or spathes that become woody at maturity. The flowers are generally small and white, radially symmetric, and can be either uni- or bisexual. The sepals and petals usually number three each and may be distinct or joined at the base. The stamens generally number six, with filaments that may be separate, attached to each other, or attached to the pistil at the base. The fruit is usually a single-seeded drupe (sometimes berry-like) but some genera (e.g., Salacca) may contain two or more seeds in each fruit.
Sawn palm stem: Palms do not form annual tree rings.
Like all monocots, palms do not have the ability to increase the width of a stem (secondary growth) via the same kind of vascular cambium found in non-monocot woody plants. This explains the cylindrical shape of the trunk (almost constant diameter) that is often seen in palms, unlike in ring-forming trees. However, many palms, like some other monocots, do have secondary growth, although because it does not arise from a single vascular cambium producing xylem inwards and phloem outwards, it is often called "anomalous secondary growth".
The Arecaceae are notable among monocots for their height and for the size of their seeds, leaves, and inflorescences. Ceroxylon quindiuense, Colombia's national tree, is the tallest monocot in the world, reaching up to 60 metres (197 ft) tall. The coco de mer (Lodoicea maldivica) has the largest seeds of any plant, 40–50 centimetres (16–20 in) in diameter and weighing 15–30 kilograms (33–66 lb) each (coconuts are the second largest). Raffia palms (Raphia spp.) have the largest leaves of any plant, up to 25 metres (82 ft) long and 3 metres (10 ft) wide. The Corypha species have the largest inflorescence of any plant, up to 7.5 metres (25 ft) tall and containing millions of small flowers. Calamus stems can reach 200 metres (656 ft) in length.
Range and habitat[edit]
This grove of the native species Washingtonia filifera in Palm Canyon, just south of Palm Springs, California, is growing alongside a stream running through the desert.
Most palms are native to tropical and subtropical climates. Palms thrive in moist and hot climates but can be found in a variety of different habitats. Their diversity is highest in wet, lowland forests. South America, the Caribbean, and areas of the South Pacific and southern Asia are regions of concentration. Colombia may have the highest number of palm species in one country. There are some palms that are also native to desert areas such as the Arabian Peninsula and parts of northwestern Mexico. Only about 130 palm species naturally grow entirely beyond the tropics, mostly in humid lowland subtropical climates, in highlands in southern Asia, and along the rim lands of the Mediterranean Sea. The northernmost native palm is Chamaerops humilis, which reaches 44°N latitude along the coast of Liguria, Italy. In the southern hemisphere, the southernmost palm is the Rhopalostylis sapida, which reaches 44°S on the Chatham Islands where an oceanic climate prevails. Cultivation of palms is possible north of subtropical climates, and some higher latitude locales such as Ireland, Scotland, England, and the Pacific Northwest feature a few palms in protected locations and microclimates. In the United States, there are at least 12 native palm species, mostly occurring in the states of the Deep South and Florida.
Palms inhabit a variety of ecosystems. More than two-thirds of palm species live in humid moist forests, where some species grow tall enough to form part of the canopy and shorter ones form part of the understory. Some species form pure stands in areas with poor drainage or regular flooding, including Raphia hookeri which is common in coastal freshwater swamps in West Africa. Other palms live in tropical mountain habitats above 1 thousand metres (3 thousand feet), such as those in the genus Ceroxylon native to the Andes. Palms may also live in grasslands and scrublands, usually associated with a water source, and in desert oases such as the date palm. A few palms are adapted to extremely basic lime soils, while others are similarly adapted to extreme potassium deficiency and toxicity of heavy metals in serpentine soils.
Taxonomy[edit]
Two Roystonea regia specimens. The characteristic crownshaft and apex shoot, or 'spear', are visible.
Palms are a monophyletic group of plants, meaning the group consists of a common ancestor and all its descendants. Extensive taxonomic research on palms began with botanist H.E. Moore, who organized palms into 15 major groups based mostly on general morphological characteristics. The following classification, proposed by N.W. Uhl and J. Dransfield in 1987, is a revision of Moore's classification that organizes palms into 6 subfamilies. A few general traits of each subfamily are listed below.
Subfamily Arecoideae are the largest subfamily with 14 tribes and containing over 100 genera. All tribes have pinnate or bipinnate leaves and flowers arranged in groups of three, with a central pistillate and two staminate flowers.
Subfamily Calamoideae includes the climbing palms, such as rattans. The leaves are usually pinnate; derived characters (synapomorphies) include spines on various organs, organs specialized for climbing, an extension of the main stem of the leaf-bearing reflexed spines, and overlapping scales covering the fruit and ovary.
Subfamily Ceroxyloideae has small to medium-sized flowers, spirally arranged, with a gynoecium of three joined carpels.
Subfamily Coryphoideae are the second-largest subfamily with 8 tribes. Most palms in this subfamily have palmately lobed leaves and solitary flowers with three, or sometimes four carpels. The fruit normally develops from only one carpel.
Subfamily Nypoideae contains only one species, Nypa fruticans, which has large, pinnate leaves. The fruit is unusual in that it floats, and the stem is underground and dichotomously branched, also unusual in palms.
The Phytelephantoideae is the sixth subfamily of Arecaceae in N.W. Uhl and J. Dransfield's 1987 classification. Members of this group have distinct monopodial flower clusters. Other distinct features include a gynoecium with five to 10 joined carpels, and flowers with more than three parts per whorl. Fruits are multiple-seeded and have multiple parts. From the modern phylogenomic data, the Phytelephantoideae are tribe in the Ceroxyloideae subfamily.
Currently, few extensive phylogenetic studies of the Arecaceae exist. In 1997, Baker et al. explored subfamily and tribe relationships using chloroplast DNA from 60 genera from all subfamilies and tribes. The results strongly showed the Calamoideae are monophyletic, and Ceroxyloideae and Coryphoideae are paraphyletic. The relationships of Arecoideae are uncertain, but they are possibly related to the Ceroxyloideae and Phytelephantoideae. Studies have suggested the lack of a fully resolved hypothesis for the relationships within the family is due to a variety of factors, including difficulties in selecting appropriate outgroups, homoplasy in morphological character states, slow rates of molecular evolution important for the use of standard DNA markers, and character polarization. However, hybridization has been observed among Orbignya and Phoenix species, and using chloroplast DNA in cladistic studies may produce inaccurate results due to maternal inheritance of the chloroplast DNA. Chemical and molecular data from non-organelle DNA, for example, could be more effective for studying palm phylogeny.
Recently, nuclear genomes and transcriptomes have been used to reconstruct the phylogeny of palms. This has revealed, for example, that a whole-genome duplication event occurred early in the evolution of the Arecaceae lineage, that was not experienced by its sister clade, the Dasypogonaceae.
For a phylogenetic tree of the family, see the list of Arecaceae genera.
Selected genera[edit]
Main articles: List of Arecaceae genera by taxonomic groups and List of Arecaceae genera by alphabetical order
Silhouette of palms in KwaZulu-Natal, South Africa
Multan, Pakistan
Various Arecaceae
Young Beccariophoenix alfredii
Cuban royal palm
Crown shaft base of Royal palm
Archontophoenix—Bangalow palm
Areca—Betel palm
Astrocaryum
Attalea
Bactris—Pupunha
Beccariophoenix—Beccariophoenix alfredii
Bismarckia—Bismarck palm
Borassus—Palmyra palm, sugar palm, toddy palm
Butia
Calamus—Rattan palm
Ceroxylon
Cocos—Coconut
Coccothrinax
Copernicia—Carnauba wax palm
Corypha—Gebang palm, Buri palm or Talipot palm
Elaeis—Oil palm
Euterpe—Cabbage heart palm, açaí palm
Hyphaene—Doum palm
Jubaea—Chilean wine palm, Coquito palm
Latania—Latan palm
Licuala
Livistona—Cabbage palm
Mauritia—Moriche palm
Metroxylon—Sago palm
Nypa—Nipa palm
Parajubaea—Bolivian coconut palms
Phoenix—Date palm
Pritchardia
Raphia—Raffia palm
Rhapidophyllum
Rhapis
Roystonea—Royal palm
Sabal—Palmettos
Salacca—Salak
Syagrus—Queen palm
Thrinax
Trachycarpus—Windmill palm, Kumaon palm
Trithrinax
Veitchia—Manila palm, Joannis palm
Washingtonia—Fan palm
Evolution[edit]
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. (January 2016) (Learn how and when to remove this template message)
The Arecaceae were the first modern family of monocots to appear in the fossil record around 80 million years ago (Mya), during the late Cretaceous period. The first modern species, such as Nypa fruticans and Acrocomia aculeata, appeared 69 Mya, as evidenced by fossil Nypa pollen. Palms appear to have undergone an early period of adaptive radiation. By 60 Mya, many of the modern, specialized genera of palms appeared and became widespread and common, much more widespread than their range today. Because palms separated from the monocots earlier than other families, they developed more intrafamilial specialization and diversity. By tracing back these diverse characteristics of palms to the basic structures of monocots, palms may be valuable in studying monocot evolution. Several species of palms have been identified from flowers preserved in amber, including Palaeoraphe dominicana and Roystonea palaea. Fossil evidence of them can also be found in samples of petrified palmwood.
The relationship between the subfamilies is shown in the following cladogram:
Arecaceae
Calamoideae
Nypoideae
Coryphoideae
Ceroxyloideae
Arecoideae
Uses[edit]
Arecaceae are common in Saudi Arabia
Palmyra palm fruit at Guntur, India
Human use of palms is at least as old as human civilization itself, starting with the cultivation of the date palm by Mesopotamians and other Middle Eastern peoples 5000 years or more ago. Date wood, pits for storing dates, and other remains of the date palm have been found in Mesopotamian sites. The date palm had a tremendous effect on the history of the Middle East. W.H. Barreveld wrote:
One could go as far as to say that, had the date palm not existed, the expansion of the human race into the hot and barren parts of the "old" world would have been much more restricted. The date palm not only provided a concentrated energy food, which could be easily stored and carried along on long journeys across the deserts, it also created a more amenable habitat for the people to live in by providing shade and protection from the desert winds (Fig. 1). In addition, the date palm also yielded a variety of products for use in agricultural production and for domestic utensils, and practically all parts of the palm had a useful purpose.
An indication of the importance of palms in ancient times is that they are mentioned more than 30 times in the Bible, and at least 22 times in the Quran.
Arecaceae have great economic importance, including coconut products, oils, dates, palm syrup, ivory nuts, carnauba wax, rattan cane, raffia, and palm wood. This family supplies a large amount of the human diet and several other human uses, both by absolute amount produced and by number of species domesticated. This is far higher than almost any other plant family, sixth out of domesticated crops in the human diet, and first in total economic value produced – sharing the top spot with the Poaceae and Fabaceae. These human uses have also spread many Arecaceae species around the world.
Along with dates mentioned above, members of the palm family with human uses are numerous.
The type member of Arecaceae is the areca palm (Areca catechu), the fruit of which, the areca nut, is chewed with the betel leaf for intoxicating effects.
Carnauba wax is harvested from the leaves of a Brazilian palm (Copernicia).
Rattans, whose stems are used extensively in furniture and baskets, are in the genus Calamus.
Palm oil is an edible vegetable oil produced by the oil palms in the genus Elaeis.
Several species are harvested for heart of palm, a vegetable eaten in salads.
Sap of the nipa palm, Nypa fruticans, is used to make vinegar.
Palm sap is sometimes fermented to produce palm wine or toddy, an alcoholic beverage common in parts of Africa, India, and the Philippines. The sap may be drunk fresh, but fermentation is rapid, reaching up to 4% alcohol content within an hour, and turning vinegary in a day.
Palmyra and date palm sap is harvested in Bengal, India, to process into gur and jaggery.
Dragon's blood, a red resin used traditionally in medicine, varnish, and dyes, may be obtained from the fruit of Daemonorops species.
Coconut is the partially edible seed of the fruit of the coconut palm (Cocos nucifera).
Coir is a coarse, water-resistant fiber extracted from the outer shell of coconuts, used in doormats, brushes, mattresses, and ropes. In India, beekeepers use coir in their bee smokers.
Some indigenous groups living in palm-rich areas use palms to make many of their necessary items and food. Sago, for example, a starch made from the pith of the trunk of the sago palm Metroxylon sagu, is a major staple food for lowland peoples of New Guinea and the Moluccas. This is not the same plant commonly used as a house plant and called "sago palm".
Palm wine is made from Jubaea also called Chilean wine palm, or coquito palm
Recently, the fruit of the açaí palm Euterpe has been used for its reputed health benefits.
Saw palmetto (Serenoa repens) is under investigation as a drug for treating enlarged prostates.
Palm leaves are also valuable to some peoples as a material for thatching, basketry, clothing, and in religious ceremonies (see "Symbolism" below).
Ornamental uses: Today, palms are valuable as ornamental plants and are often grown along streets in tropical and subtropical cities. Chamaedorea elegans is a popular houseplant and is grown indoors for its low maintenance. Farther north, palms are a common feature in botanical gardens or as indoor plants. Few palms tolerate severe cold and the majority of the species are tropical or subtropical. The three most cold-tolerant species are Trachycarpus fortunei, native to eastern Asia, and Rhapidophyllum hystrix and Sabal minor, both native to the southeastern United States.
The southeastern U.S. state of South Carolina is nicknamed the Palmetto State after the sabal palmetto (cabbage palmetto), logs from which were used to build the fort at Fort Moultrie. During the American Revolutionary War, they were invaluable to those defending the fort, because their spongy wood absorbed or deflected the British cannonballs.
Singaporean politician Tan Cheng Bock uses a palm tree-like symbol similar to a Ravenala to represent him in the 2011 Singaporean presidential election. The symbol of a party he founded, Progress Singapore Party, was also based on a palm tree.
On Ash Wednesday, Catholics receive a cross on their forehead made of palm ashes as a reminder of the Catholic belief that everyone and everything eventually returns to where it came from, commonly expressed by the saying "ashes to ashes and dust to dust".
Fruit of the date palm Phoenix dactylifera
Washingtonia robusta palms line Ocean Avenue in Santa Monica, California.
Rodeo Palms, a subdivision in Manvel, Texas
Sabal palm in the Canaveral National Seashore
Coconut flowers
Close-up of the top, Atlantic Ocean, Georgia, U.S.
Endangered species[edit]
Pritchardia affinis, a critically endangered species endemic to the Hawaiian Islands
Like many other plants, palms have been threatened by human intervention and exploitation. The greatest risk to palms is destruction of habitat, especially in the tropical forests, due to urbanization, wood-chipping, mining, and conversion to farmland. Palms rarely reproduce after such great changes in the habitat, and those with small habitat ranges are most vulnerable to them. The harvesting of heart of palm, a delicacy in salads, also poses a threat because it is derived from the palm's apical meristem, a vital part of the palm that cannot be regrown (except in domesticated varieties, e.g. of peach palm). The use of rattan palms in furniture has caused a major population decrease in these species that has negatively affected local and international markets, as well as biodiversity in the area. The sale of seeds to nurseries and collectors is another threat, as the seeds of popular palms are sometimes harvested directly from the wild. In 2006, at least 100 palm species were considered endangered, and nine species have been reported as recently extinct.
However, several factors make palm conservation more difficult. Palms live in almost every type of warm habitat and have tremendous morphological diversity. Most palm seeds lose viability quickly, and they cannot be preserved in low temperatures because the cold kills the embryo. Using botanical gardens for conservation also presents problems, since they can rarely house more than a few plants of any species or truly imitate the natural setting. There is also the risk that cross-pollination can lead to hybrid species.
The Palm Specialist Group of the World Conservation Union (IUCN) began in 1984, and has performed a series of three studies to find basic information on the status of palms in the wild, use of wild palms, and palms under cultivation. Two projects on palm conservation and use supported by the World Wildlife Fund took place from 1985 to 1990 and 1986–1991, in the American tropics and southeast Asia, respectively. Both studies produced copious new data and publications on palms. Preparation of a global action plan for palm conservation began in 1991, supported by the IUCN, and was published in 1996.
The rarest palm known is Hyophorbe amaricaulis. The only living individual remains at the Botanic Gardens of Curepipe in Mauritius.
Arthropod pests[edit]
Some pests are specialists to particular taxa. Pests that attack a variety of species of palms include:
Raoiella indica, the red palm mite
Caryobruchus gleditsiae, the palm seed beetle or palm seed weevil
Rhynchophorus ferrugineus, the red palm weevil, recently introduced to Europe
Symbolism[edit]
Main article: Palm branch (symbol)
Edward Hitchcock's fold-out paleontological chart in his 1840 Elementary Geology, showing the Palms as the crown of the plant tree of life, alongside Man as the crown of the animal tree of life.
The palm branch was a symbol of triumph and victory in classical antiquity. The Romans rewarded champions of the games and celebrated military successes with palm branches. Early Christians used the palm branch to symbolize the victory of the faithful over enemies of the soul, as in the Palm Sunday festival celebrating the triumphal entry of Jesus Christ into Jerusalem. In Judaism, the palm represents peace and plenty, and is one of the Four Species of Sukkot; the palm may also symbolize the Tree of Life in Kabbalah.
The canopies of the Rathayatra carts which carry the deities of Krishna and his family members in the cart festival of Jagganath Puri in India are marked with the emblem of a palm tree. Specifically it is the symbol of Krishna's brother, Baladeva.
In 1840, the American geologist Edward Hitchcock (1793–1864) published the first tree-like paleontology chart in his Elementary Geology, with two separate trees of life for the plants and the animals. These are crowned (graphically) with the Palms and with Man.
Today, the palm, especially the coconut palm, remains a symbol of the tropical island paradise.
Palms appear on the flags and seals of several places where they are native, including those of Haiti, Guam, Saudi Arabia, Florida, and South Carolina.
Palm trees on farm blown by wind.
Other plants[edit]
Some species commonly called palms, though they are not true palms, include:
Ailanthus altissima (Ghetto palm), a tree in the flowering plant family Simaroubaceae
Alocasia odora x gageana 'Calidora' (Persian palm), a flowering plant in the family Araceae
Aloe thraskii (Palm aloe), a flowering plant in the family Asphodelaceae
Amorphophallus konjac (Snake palm), a flowering plant in the family Araceae
Beaucarnea recurvata (Ponytail palm), a flowering plant in the family Asparagaceae
Begonia luxurians (Palm leaf begonia), a flowering plant in the family Begoniaceae
Biophytum umbraculum (South Pacific palm), a flowering plant in the family Oxalidaceae
Blechnum appendiculatum (Palm fern), a fern in the family Aspleniaceae
Brassica oleracea 'Lacinato kale' (Black Tuscan palm), a flowering plant in the family Brassicaceae
Brighamia insignis (Vulcan palm), a flowering plant in the family Campanulaceae
Carludovica palmata (Panama hat palm) and perhaps other members in the family Cyclanthaceae.
Cordyline australis (Cabbage palm, Torbay palm, ti palm) or palm lily (family Asparagaceae) and other representatives in the genus Cordyline.
Cyathea cunninghamii (Palm fern) and other tree ferns (families Cyatheaceae and Dicksoniaceae) that may be confused with palms.
Cycas revoluta (Sago palm) and the rest of the order Cycadales.
Cyperus alternifolius (Umbrella palm), a sedge in the family Cyperaceae
Dasylirion longissimum (Grass palm), a flowering plant in the family Asparagaceae and other plants in the genus Dasylirion
Dioon spinulosum (Gum palm), a cycad in the family Zamiaceae
Dracaena marginata (Dragon palm) a flowering plant in the family Asparagaceae
Eisenia arborea (Southern sea palm), a species of brown alga in the family Lessoniaceae
Fatsia japonica (Figleaf palm), a flowering plant in the family Araliaceae
Hypnodendron comosum (Palm tree moss or palm moss), a moss in the family Hypnodendraceae
Musa species (Banana palm), a flowering plant in the family Musaceae
Pachypodium lamerei (Madagascar palm), a flowering plant in the family Apocynaceae
Pandanus spiralis (Screw palm), a flowering plant in the family Pandanaceae and perhaps other Pandanus spp.
Ravenala (Traveller's palm), a flowering plant in the family Strelitziaceae
Setaria palmifolia (Palm grass), a grass in the family Poaceae
Yucca brevifolia (Yucca palm or palm tree yucca)
Yucca filamentosa (Needle palm) and Yucca filifera (St. Peter's palm), flowering plants in the family Asparagaceae
Zamia furfuracea (Cardboard palm), a cycad in the family Zamiaceae
Zamioculcas zamiifolia (Emerald palm or aroid palm), a flowering plant in the family Araceae
See also[edit]
Coconut
Fan palm—genera with palmate leaves
List of Arecaceae genera
List of foliage plant diseases (Arecaceae)
List of hardy palms—palms able to withstand colder temperatures
Postelsia—called the "sea palm" (a brown alga) | biology | 4099754 | https://sv.wikipedia.org/wiki/Picramnia%20ramiflora | Picramnia ramiflora | Picramnia ramiflora är en tvåhjärtbladig växtart som beskrevs av Jules Émile Planchon. Picramnia ramiflora ingår i släktet Picramnia och familjen Picramniaceae. Inga underarter finns listade.
Källor
Tvåhjärtbladiga blomväxter
ramiflora | swedish | 0.739987 |
coconut_three_holes/Gynoecium.txt | Gynoecium (/ɡaɪˈniːsi.əm, dʒɪˈniːʃi.əm/; from Ancient Greek γυνή (gunḗ) 'woman, female', and οἶκος (oîkos) 'house'; pl.: gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) pistils and is typically surrounded by the pollen-producing reproductive organs, the stamens, collectively called the androecium. The gynoecium is often referred to as the "female" portion of the flower, although rather than directly producing female gametes (i.e. egg cells), the gynoecium produces megaspores, each of which develops into a female gametophyte which then produces egg cells.
The term gynoecium is also used by botanists to refer to a cluster of archegonia and any associated modified leaves or stems present on a gametophyte shoot in mosses, liverworts, and hornworts. The corresponding terms for the male parts of those plants are clusters of antheridia within the androecium. Flowers that bear a gynoecium but no stamens are called pistillate or carpellate. Flowers lacking a gynoecium are called staminate.
The gynoecium is often referred to as female because it gives rise to female (egg-producing) gametophytes; however, strictly speaking sporophytes do not have a sex, only gametophytes do. Gynoecium development and arrangement is important in systematic research and identification of angiosperms, but can be the most challenging of the floral parts to interpret.
Introduction[edit]
Unlike (most) animals, plants grow new organs after embryogenesis, including new roots, leaves, and flowers. In the flowering plants, the gynoecium develops in the central region of the flower as a carpel or in groups of fused carpels. After fertilization, the gynoecium develops into a fruit that provides protection and nutrition for the developing seeds, and often aids in their dispersal. The gynoecium has several specialized tissues. The tissues of the gynoecium develop from genetic and hormonal interactions along three-major axes. These tissue arise from meristems that produce cells that differentiate into the different tissues that produce the parts of the gynoecium including the pistil, carpels, ovary, and ovals; the carpel margin meristem (arising from the carpel primordium) produces the ovules, ovary septum, and the transmitting track, and plays a role in fusing the apical margins of carpels.
Pistil[edit]
"Pistil" redirects here. Not to be confused with Pistol.
A syncarpous gynoecium in context. The gynoecium (whether composed of a single carpel or multiple "fused" carpels) is typically made up of an ovary, style, and stigma as in the center of the flower.
The gynoecium may consist of one or more separate pistils. A pistil typically consists of an expanded basal portion called an ovary, an elongated section called a style and an apical structure called a stigma that receives pollen
The ovary (from Latin ovum, meaning egg) is the enlarged basal portion which contains placentas, ridges of tissue bearing one or more ovules (integumented megasporangia). The placentas and/or ovule(s) may be born on the gynoecial appendages or less frequently on the floral apex. The chamber in which the ovules develop is called a locule (or sometimes cell).
The style (from Ancient Greek στῦλος, stylos, meaning a pillar) is a pillar-like stalk through which pollen tubes grow to reach the ovary. Some flowers, such as those of Tulipa, do not have a distinct style, and the stigma sits directly on the ovary. The style is a hollow tube in some plants, such as lilies, or has transmitting tissue through which the pollen tubes grow.
The stigma (from Ancient Greek στίγμα, stigma, meaning mark or puncture) is usually found at the tip of the style, the portion of the carpel(s) that receives pollen (male gametophytes). It is commonly sticky or feathery to capture pollen.
The word "pistil" comes from Latin pistillum meaning pestle. A sterile pistil in a male flower is referred to as a pistillode.
Carpels[edit]
The pistils of a flower are considered to be composed of one or more carpels. A carpel is the female reproductive part of the flower—usually composed of the style, and stigma (sometimes having its individual ovary, and sometimes connecting to a shared basal ovary) —and usually interpreted as modified leaves that bear structures called ovules, inside which egg cells ultimately form. A pistil may consist of one carpel (with its ovary, style and stigma); or it may comprise several carpels joined together to form a single ovary, the whole unit called a pistil. The gynoecium may present as one or more uni-carpellate pistils or as one multi-carpellate pistil. (The number of carpels is denoted by terms such as tricarpellate (three carpels).)
Carpels are thought to be phylogenetically derived from ovule-bearing leaves or leaf homologues (megasporophylls), which evolved to form a closed structure containing the ovules. This structure is typically rolled and fused along the margin.
Although many flowers satisfy the above definition of a carpel, there are also flowers that do not have carpels because in these flowers the ovule(s), although enclosed, are borne directly on the floral apex. Therefore, the carpel has been redefined as an appendage that encloses ovule(s) and may or may not bear them. However, the most unobjectionable definition of the carpel is simply that of an appendage that encloses an ovule or ovules.
Centre of a Ranunculus repens (creeping buttercup) showing multiple unfused carpels surrounded by longer stamens
Cross-section through the ovary of Narcissus showing multiple connate carpels (a compound pistil) fused along the placental line where the ovules form in each locule
Pistil of Begonia grandis
Types[edit]
If a gynoecium has a single carpel, it is called monocarpous. If a gynoecium has multiple, distinct (free, unfused) carpels, it is apocarpous. If a gynoecium has multiple carpels "fused" into a single structure, it is syncarpous. A syncarpous gynoecium can sometimes appear very much like a monocarpous gynoecium.
Comparison of gynoecium terminology using carpel and pistil
Gynoecium composition
Carpelterminology
Pistil terminology
Examples
Single carpel
Monocarpous (unicarpellate) gynoecium
A pistil (simple)
Avocado (Persea sp.), most legumes (Fabaceae)
Multiple distinct ("unfused") carpels
Apocarpous (choricarpous) gynoecium
Pistils (simple)
Strawberry (Fragaria sp.), Buttercup (Ranunculus sp.)
Multiple connate ("fused") carpels
Syncarpous gynoecium
A pistil (compound)
Tulip (Tulipa sp.), most flowers
The degree of connation ("fusion") in a syncarpous gynoecium can vary. The carpels may be "fused" only at their bases, but retain separate styles and stigmas. The carpels may be "fused" entirely, except for retaining separate stigmas. Sometimes (e.g., Apocynaceae) carpels are fused by their styles or stigmas but possess distinct ovaries. In a syncarpous gynoecium, the "fused" ovaries of the constituent carpels may be referred to collectively as a single compound ovary. It can be a challenge to determine how many carpels fused to form a syncarpous gynoecium. If the styles and stigmas are distinct, they can usually be counted to determine the number of carpels. Within the compound ovary, the carpels may have distinct locules divided by walls called septa. If a syncarpous gynoecium has a single style and stigma and a single locule in the ovary, it may be necessary to examine how the ovules are attached. Each carpel will usually have a distinct line of placentation where the ovules are attached.
Pistil development[edit]
Pistils begin as small primordia on a floral apical meristem, forming later than, and closer to the (floral) apex than sepal, petal and stamen primordia. Morphological and molecular studies of pistil ontogeny reveal that carpels are most likely homologous to leaves.
A carpel has a similar function to a megasporophyll, but typically includes a stigma, and is fused, with ovules enclosed in the enlarged lower portion, the ovary.
In some basal angiosperm lineages, Degeneriaceae and Winteraceae, a carpel begins as a shallow cup where the ovules develop with laminar placentation, on the upper surface of the carpel. The carpel eventually forms a folded, leaf-like structure, not fully sealed at its margins. No style exists, but a broad stigmatic crest along the margin allows pollen tubes access along the surface and between hairs at the margins.
Two kinds of fusion have been distinguished: postgenital fusion that can be observed during the development of flowers, and congenital fusion that cannot be observed i.e., fusions that occurred during phylogeny. But it is very difficult to distinguish fusion and non-fusion processes in the evolution of flowering plants. Some processes that have been considered congenital (phylogenetic) fusions appear to be non-fusion processes such as, for example, the de novo formation of intercalary growth in a ring zone at or below the base of primordia. Therefore, "it is now increasingly acknowledged that the term 'fusion,' as applied to phylogeny (as in 'congenital fusion') is ill-advised."
Gynoecium position[edit]
Basal angiosperm groups tend to have carpels arranged spirally around a conical or dome-shaped receptacle. In later lineages, carpels tend to be in whorls.
The relationship of the other flower parts to the gynoecium can be an important systematic and taxonomic character. In some flowers, the stamens, petals, and sepals are often said to be "fused" into a "floral tube" or hypanthium. However, as Leins & Erbar (2010) pointed out, "the classical view that the wall of the inferior ovary results from the "congenital" fusion of dorsal carpel flanks and the floral axis does not correspond to the ontogenetic processes that can actually be observed. All that can be seen is an intercalary growth in a broad circular zone that changes the shape of the floral axis (receptacle)." And what happened during evolution is not a phylogenetic fusion but the formation of a unitary intercalary meristem. Evolutionary developmental biology investigates such developmental processes that arise or change during evolution.
If the hypanthium is absent, the flower is hypogynous, and the stamens, petals, and sepals are all attached to the receptacle below the gynoecium. Hypogynous flowers are often referred to as having a superior ovary. This is the typical arrangement in most flowers.
If the hypanthium is present up to the base of the style(s), the flower is epigynous. In an epigynous flower, the stamens, petals, and sepals are attached to the hypanthium at the top of the ovary or, occasionally, the hypanthium may extend beyond the top of the ovary. Epigynous flowers are often referred to as having an inferior ovary. Plant families with epigynous flowers include orchids, asters, and evening primroses.
Between these two extremes are perigynous flowers, in which a hypanthium is present, but is either free from the gynoecium (in which case it may appear to be a cup or tube surrounding the gynoecium) or connected partly to the gynoecium (with the stamens, petals, and sepals attached to the hypanthium part of the way up the ovary). Perigynous flowers are often referred to as having a half-inferior ovary (or, sometimes, partially inferior or half-superior). This arrangement is particularly frequent in the rose family and saxifrages.
Occasionally, the gynoecium is born on a stalk, called the gynophore, as in Isomeris arborea.
Flowers and fruit (capsules) of the ground orchid, Spathoglottis plicata, illustrating an inferior ovary.
Illustration showing longitudinal sections through hypogynous (a), perigynous (b), and epigynous (c) flowers
Placentation[edit]
Main article: Ovule
Within the ovary, each ovule is born by a placenta or arises as a continuation of the floral apex. The placentas often occur in distinct lines called lines of placentation. In monocarpous or apocarpous gynoecia, there is typically a single line of placentation in each ovary. In syncarpous gynoecia, the lines of placentation can be regularly spaced along the wall of the ovary (parietal placentation), or near the center of the ovary. In the latter case, separate terms are used depending on whether or not the ovary is divided into separate locules. If the ovary is divided, with the ovules born on a line of placentation at the inner angle of each locule, this is axile placentation. An ovary with free central placentation, on the other hand, consists of a single compartment without septae and the ovules are attached to a central column that arises directly from the floral apex (axis). In some cases a single ovule is attached to the bottom or top of the locule (basal or apical placentation, respectively).
The ovule[edit]
Main article: Ovule
Longitudinal section of carpellate flower of squash showing ovary, ovules, stigma, style, and petals
In flowering plants, the ovule (from Latin ovulum meaning small egg) is a complex structure born inside ovaries. The ovule initially consists of a stalked, integumented megasporangium (also called the nucellus). Typically, one cell in the megasporangium undergoes meiosis resulting in one to four megaspores. These develop into a megagametophyte (often called the embryo sac) within the ovule. The megagametophyte typically develops a small number of cells, including two special cells, an egg cell and a binucleate central cell, which are the gametes involved in double fertilization. The central cell, once fertilized by a sperm cell from the pollen becomes the first cell of the endosperm, and the egg cell once fertilized become the zygote that develops into the embryo. The gap in the integuments through which the pollen tube enters to deliver sperm to the egg is called the micropyle. The stalk attaching the ovule to the placenta is called the funiculus.
Role of the stigma and style[edit]
Main article: Stigma (botany)
Stigmas can vary from long and slender to globe-shaped to feathery. The stigma is the receptive tip of the carpel(s), which receives pollen at pollination and on which the pollen grain germinates. The stigma is adapted to catch and trap pollen, either by combining pollen of visiting insects or by various hairs, flaps, or sculpturings.
The style and stigma of the flower are involved in most types of self incompatibility reactions. Self-incompatibility, if present, prevents fertilization by pollen from the same plant or from genetically similar plants, and ensures outcrossing.
The primitive development of carpels, as seen in such groups of plants as Tasmannia and Degeneria, lack styles and the stigmatic surface is produced along the carpels margins.
Stigmas and style of Cannabis sativa held in a pair of forceps
Stigma of a Crocus flower.
See also[edit]
Chalaza
Notes[edit]
^ carpel (also carpophyl)—Gr. καρπός (karpós, "fruit") + Gr. φύλλον (phúllon, "leaf") [L. folium]. | biology | 1468980 | https://sv.wikipedia.org/wiki/F%C3%B6nsterviva | Fönsterviva | Fönsterviva (Primula obconica) är en perennväxt i vivesläktet. Namnet obconica betyder "som en inverterad kon" och syftar på blompipens form.
Utbredning
Fönsterviva växer i Kina, i bergsområdena Guangdong, Guizhou, Hubei, Sichuan och Yunnan. I övriga världen är den en omtyckt inomhusväxt eller ettårig trädgårdsväxt.
Utseende och ekologi
Fönstervivan är en 2,5–25 centimeter hög ört (den stora variationen i höjd beror på växtplatsen). Den förekommer på cirka 1 000 meters höjd över havet i steniga, skuggiga marker och föredrar kalkberggrund. Vivan får stora (2,5–6 cm) blommor som i det vilda varierar från vitt genom rosa till ljuslila, med kontrastfärg runt mitten. Pipen är konisk och fönstervivan är likt andra vivor heterostyl med oliklånga stift och ståndare. Varje stjälk bär en flock med 5–10 blommor. Fodret är trattlikt och har korta flikar. De långskaftade bladen sitter i rosett från en jordstam, är runda och smått tandade. Hela växten är mycket hårig och har inget puder (vilket många andra vivor har). Frukten är en rund kapsel med kvarsittande foder. Den öppnas genom att väggarna faller sönder.
Allergi mot fönsterviva
Trädgårdsmästare som handskas mycket med fönsterviva kan få primuladermatit, ett eksem. Fönstervivans blad och stjälkar är fulla av små glandelhår (körtelhår) som brister när man rör vid växten - och då släpper ut primulin och andra ämnen. De allergena ämnena är dock inte luftburna. Även vissna blad har kvar sina glandelhår. Primuladermatit kan uppstå fort och reaktionen kan bli kraftig, med blåsor och svullnad, redan vid andra beröringen. Vissa odlade former har inga allergena ämnen.
Variation inom arten
Några vilda former av fönstervivan har fått egna formella namn. Det finns också odlade namnsorter, som "Touch Me".
P. obconica var. nigroglandulosa W. W. Smith & Fletcher
P. obconica var. obconica
P. obconica var. rotundifolia Franchet
P. obconica var. werringtonensis (Forrest) W. W. Smith & Fletcher
Referenser
Externa länkar
Viveväxter
Fö Växtindex | swedish | 0.741896 |
evolutionary_advantage_of_red-green_color_blindness/Color.txt |
Color (American English) or colour (Commonwealth English) is the visual perception based on the electromagnetic spectrum. Though color is not an inherent property of matter, color perception is related to an object's light absorption, reflection, emission spectra and interference. For most humans, colors are perceived in the visible light spectrum with three types of cone cells (trichromacy). Other animals may have a different number of cone cell types or have eyes sensitive to different wavelength, such as bees that can distinguish ultraviolet, and thus have a different color sensitivity range. Animal perception of color originates from different light wavelength or spectral sensitivity in cone cell types, which is then processed by the brain.
Colors have perceived properties such as hue, colorfulness (saturation) and luminance. Colors can also be additively mixed (commonly used for actual light) or subtractively mixed (commonly used for materials). If the colors are mixed in the right proportions, because of metamerism, they may look the same as a single-wavelength light. For convenience, colors can be organized in a color space, which when being abstracted as a mathematical color model can assign each region of color with a corresponding set of numbers. As such, color spaces are an essential tool for color reproduction in print, photography, computer monitors and television. The most well-known color models are RGB, CMYK, YUV, HSL and HSV.
Because the perception of color is an important aspect of human life, different colors have been associated with emotions, activity, and nationality. Names of color regions in different cultures can have different, sometimes overlapping areas. In visual arts, color theory is used to govern the use of colors in an aesthetically pleasing and harmonious way. The theory of color includes the color complements; color balance; and classification of primary colors (traditionally red, yellow, blue), secondary colors (traditionally orange, green, purple) and tertiary colors. The study of colors in general is called color science.
Physical properties
The visible spectrum perceived from 390 to 710 nm wavelength
Electromagnetic radiation is characterized by its wavelength (or frequency) and its intensity. When the wavelength is within the visible spectrum (the range of wavelengths humans can perceive, approximately from 390 nm to 700 nm), it is known as "visible light".
Most light sources emit light at many different wavelengths; a source's spectrum is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color sensation in that direction, there are many more possible spectral combinations than color sensations. In fact, one may formally define a color as a class of spectra that give rise to the same color sensation, although such classes would vary widely among different species, and to a lesser extent among individuals within the same species. In each such class, the members are called metamers of the color in question. This effect can be visualized by comparing the light sources' spectral power distributions and the resulting colors.
Spectral colors
Main article: Spectral color
The familiar colors of the rainbow in the spectrum—named using the Latin word for appearance or apparition by Isaac Newton in 1671—include all those colors that can be produced by visible light of a single wavelength only, the pure spectral or monochromatic colors. The spectrum above shows approximate wavelengths (in nm) for spectral colors in the visible range. Spectral colors have 100% purity, and are fully saturated. A complex mixture of spectral colors can be used to describe any color, which is the definition of a light power spectrum.
The spectral colors form a continuous spectrum, and how it is divided into distinct colors linguistically is a matter of culture and historical contingency. Despite the ubiquitous ROYGBIV mnemonic used to remember the spectral colors in English, the inclusion or exclusion of colors is contentious, with disagreement often focused on indigo and cyan. Even if the subset of color terms is agreed, their wavelength ranges and borders between them may not be.
The intensity of a spectral color, relative to the context in which it is viewed, may alter its perception considerably according to the Bezold–Brücke shift; for example, a low-intensity orange-yellow is brown, and a low-intensity yellow-green is olive green. In color models capable of representing spectral colors, such as CIELUV, a spectral color has the maximal saturation. In Helmholtz coordinates, this is described as 100% purity.
Color of objects
The physical color of an object depends on how it absorbs and scatters light. Most objects scatter light to some degree and do not reflect or transmit light specularly like glasses or mirrors. A transparent object allows almost all light to transmit or pass through, thus transparent objects are perceived as colorless. Conversely, an opaque object does not allow light to transmit through and instead absorbing or reflecting the light it receives. Like transparent objects, translucent objects allow light to transmit through, but translucent objects are seen colored because they scatter or absorb certain wavelengths of light via internal scatterance. The absorbed light is often dissipated as heat.
Color vision
Main article: Color vision
Development of theories of color vision
Main article: Color theory
The upper disk and the lower disk have exactly the same objective color, and are in identical gray surroundings; based on context differences, humans perceive the squares as having different reflectances, and may interpret the colors as different color categories; see checker shadow illusion.
Although Aristotle and other ancient scientists had already written on the nature of light and color vision, it was not until Newton that light was identified as the source of the color sensation. In 1810, Goethe published his comprehensive Theory of Colors in which he provided a rational description of color experience, which 'tells us how it originates, not what it is'. (Schopenhauer)
In 1801 Thomas Young proposed his trichromatic theory, based on the observation that any color could be matched with a combination of three lights. This theory was later refined by James Clerk Maxwell and Hermann von Helmholtz. As Helmholtz puts it, "the principles of Newton's law of mixture were experimentally confirmed by Maxwell in 1856. Young's theory of color sensations, like so much else that this marvelous investigator achieved in advance of his time, remained unnoticed until Maxwell directed attention to it."
At the same time as Helmholtz, Ewald Hering developed the opponent process theory of color, noting that color blindness and afterimages typically come in opponent pairs (red-green, blue-orange, yellow-violet, and black-white). Ultimately these two theories were synthesized in 1957 by Hurvich and Jameson, who showed that retinal processing corresponds to the trichromatic theory, while processing at the level of the lateral geniculate nucleus corresponds to the opponent theory.
In 1931, an international group of experts known as the Commission internationale de l'éclairage (CIE) developed a mathematical color model, which mapped out the space of observable colors and assigned a set of three numbers to each.
Color in the eye
Main article: Color vision § Cone cells in the human eye
Normalized typical human cone cell responses (S, M, and L types) to monochromatic spectral stimuli
The ability of the human eye to distinguish colors is based upon the varying sensitivity of different cells in the retina to light of different wavelengths. Humans are trichromatic—the retina contains three types of color receptor cells, or cones. One type, relatively distinct from the other two, is most responsive to light that is perceived as blue or blue-violet, with wavelengths around 450 nm; cones of this type are sometimes called short-wavelength cones or S cones (or misleadingly, blue cones). The other two types are closely related genetically and chemically: middle-wavelength cones, M cones, or green cones are most sensitive to light perceived as green, with wavelengths around 540 nm, while the long-wavelength cones, L cones, or red cones, are most sensitive to light that is perceived as greenish yellow, with wavelengths around 570 nm.
Light, no matter how complex its composition of wavelengths, is reduced to three color components by the eye. Each cone type adheres to the principle of univariance, which is that each cone's output is determined by the amount of light that falls on it over all wavelengths. For each location in the visual field, the three types of cones yield three signals based on the extent to which each is stimulated. These amounts of stimulation are sometimes called tristimulus values.
The response curve as a function of wavelength varies for each type of cone. Because the curves overlap, some tristimulus values do not occur for any incoming light combination. For example, it is not possible to stimulate only the mid-wavelength (so-called "green") cones; the other cones will inevitably be stimulated to some degree at the same time. The set of all possible tristimulus values determines the human color space. It has been estimated that humans can distinguish roughly 10 million different colors.
The other type of light-sensitive cell in the eye, the rod, has a different response curve. In normal situations, when light is bright enough to strongly stimulate the cones, rods play virtually no role in vision at all. On the other hand, in dim light, the cones are understimulated leaving only the signal from the rods, resulting in a colorless response. (Furthermore, the rods are barely sensitive to light in the "red" range.) In certain conditions of intermediate illumination, the rod response and a weak cone response can together result in color discriminations not accounted for by cone responses alone. These effects, combined, are summarized also in the Kruithof curve, which describes the change of color perception and pleasingness of light as a function of temperature and intensity.
Color in the brain
Main article: Color vision § Color in the primate brain
While the mechanisms of color vision at the level of the retina are well-described in terms of tristimulus values, color processing after that point is organized differently. A dominant theory of color vision proposes that color information is transmitted out of the eye by three opponent processes, or opponent channels, each constructed from the raw output of the cones: a red–green channel, a blue–yellow channel, and a black–white "luminance" channel. This theory has been supported by neurobiology, and accounts for the structure of our subjective color experience. Specifically, it explains why humans cannot perceive a "reddish green" or "yellowish blue", and it predicts the color wheel: it is the collection of colors for which at least one of the two color channels measures a value at one of its extremes.
The exact nature of color perception beyond the processing already described, and indeed the status of color as a feature of the perceived world or rather as a feature of our perception of the world—a type of qualia—is a matter of complex and continuing philosophical dispute.
The visual dorsal stream (green) and ventral stream (purple) are shown. The ventral stream is responsible for color perception.
From the V1 blobs, color information is sent to cells in the second visual area, V2. The cells in V2 that are most strongly color tuned are clustered in the "thin stripes" that, like the blobs in V1, stain for the enzyme cytochrome oxidase (separating the thin stripes are interstripes and thick stripes, which seem to be concerned with other visual information like motion and high-resolution form). Neurons in V2 then synapse onto cells in the extended V4. This area includes not only V4, but two other areas in the posterior inferior temporal cortex, anterior to area V3, the dorsal posterior inferior temporal cortex, and posterior TEO. Area V4 was initially suggested by Semir Zeki to be exclusively dedicated to color, and he later showed that V4 can be subdivided into subregions with very high concentrations of color cells separated from each other by zones with lower concentration of such cells though even the latter cells respond better to some wavelengths than to others, a finding confirmed by subsequent studies. The presence in V4 of orientation-selective cells led to the view that V4 is involved in processing both color and form associated with color but it is worth noting that the orientation selective cells within V4 are more broadly tuned than their counterparts in V1, V2 and V3. Color processing in the extended V4 occurs in millimeter-sized color modules called globs. This is the part of the brain in which color is first processed into the full range of hues found in color space.
Nonstandard color perception
Color vision deficiency
Main article: Color blindness
A color vision deficiency causes an individual to perceive a smaller gamut of colors than the standard observer with normal color vision. The effect can be mild, having lower "color resolution" (i.e. anomalous trichromacy), moderate, lacking an entire dimension or channel of color (e.g. dichromacy), or complete, lacking all color perception (i.e. monochromacy). Most forms of color blindness derive from one or more of the three classes of cone cells either being missing, having a shifted spectral sensitivity or having lower responsiveness to incoming light. In addition, cerebral achromatopsia is caused by neural anomalies in those parts of the brain where visual processing takes place.
Some colors that appear distinct to an individual with normal color vision will appear metameric to the color blind. The most common form of color blindness is congenital red–green color blindness, affecting ~8% of males. Individuals with the strongest form of this condition (dichromacy) will experience blue and purple, green and yellow, teal and gray as colors of confusion, i.e. metamers.
Tetrachromacy
Main article: Tetrachromacy
Outside of humans, which are mostly trichromatic (having three types of cones), most mammals are dichromatic, possessing only two cones. However, outside of mammals, most vertebrate are tetrachromatic, having four types of cones, and includes most, birds, reptiles, amphibians and bony fish. An extra dimension of color vision means these vertebrates can see two distinct colors that a normal human would view as metamers. Some invertebrates, such as the mantis shrimp, have an even higher number of cones (12) that could lead to a richer color gamut than even imaginable by humans.
The existence of human tetrachromats is a contentious notion. As many as half of all human females have 4 distinct cone classes, which could enable tetrachromacy. However, a distinction must be made between retinal (or weak) tetrachromats, which express four cone classes in the retina, and functional (or strong) tetrachromats, which are able to make the enhanced color discriminations expected of tetrachromats. In fact, there is only one peer-reviewed report of a functional tetrachromat. It is estimated that while the average person is able to see one million colors, someone with functional tetrachromacy could see a hundred million colors.
Synesthesia
Main article: Synesthesia
In certain forms of synesthesia, perceiving letters and numbers (grapheme–color synesthesia) or hearing sounds (chromesthesia) will evoke a perception of color. Behavioral and functional neuroimaging experiments have demonstrated that these color experiences lead to changes in behavioral tasks and lead to increased activation of brain regions involved in color perception, thus demonstrating their reality, and similarity to real color percepts, albeit evoked through a non-standard route. Synesthesia can occur genetically, with 4% of the population having variants associated with the condition. Synesthesia has also been known to occur with brain damage, drugs, and sensory deprivation.
The philosopher Pythagoras experienced synesthesia and provided one of the first written accounts of the condition in approximately 550 BCE. He created mathematical equations for musical notes that could form part of a scale, such as an octave.
Afterimages
Main article: Afterimage
After exposure to strong light in their sensitivity range, photoreceptors of a given type become desensitized. For a few seconds after the light ceases, they will continue to signal less strongly than they otherwise would. Colors observed during that period will appear to lack the color component detected by the desensitized photoreceptors. This effect is responsible for the phenomenon of afterimages, in which the eye may continue to see a bright figure after looking away from it, but in a complementary color. Afterimage effects have also been used by artists, including Vincent van Gogh.
Color constancy
Main article: Color constancy
When an artist uses a limited color palette, the human eye tends to compensate by seeing any gray or neutral color as the color which is missing from the color wheel. For example, in a limited palette consisting of red, yellow, black, and white, a mixture of yellow and black will appear as a variety of green, a mixture of red and black will appear as a variety of purple, and pure gray will appear bluish.
The trichromatic theory is strictly true when the visual system is in a fixed state of adaptation. In reality, the visual system is constantly adapting to changes in the environment and compares the various colors in a scene to reduce the effects of the illumination. If a scene is illuminated with one light, and then with another, as long as the difference between the light sources stays within a reasonable range, the colors in the scene appear relatively constant to us. This was studied by Edwin H. Land in the 1970s and led to his retinex theory of color constancy.
Both phenomena are readily explained and mathematically modeled with modern theories of chromatic adaptation and color appearance (e.g. CIECAM02, iCAM). There is no need to dismiss the trichromatic theory of vision, but rather it can be enhanced with an understanding of how the visual system adapts to changes in the viewing environment.
Reproduction
Main article: Color reproduction
The CIE 1931 color space xy chromaticity diagram with the visual locus plotted using the CIE (2006) physiologically relevant LMS fundamental color matching functions transformed into the CIE 1931 xy color space and converted into Adobe RGB. The triangle shows the gamut of Adobe RGB. The Planckian locus is shown with color temperatures labeled in Kelvins. The outer curved boundary is the spectral (or monochromatic) locus, with wavelengths shown in nanometers. The colors in this file are being specified using Adobe RGB. Areas outside the triangle cannot be accurately rendered since they are outside the gamut of Adobe RGB, therefore they have been interpreted. The colors depicted depend on the gamut and color accuracy of your display.
Color reproduction is the science of creating colors for the human eye that faithfully represent the desired color. It focuses on how to construct a spectrum of wavelengths that will best evoke a certain color in an observer. Most colors are not spectral colors, meaning they are mixtures of various wavelengths of light. However, these non-spectral colors are often described by their dominant wavelength, which identifies the single wavelength of light that produces a sensation most similar to the non-spectral color. Dominant wavelength is roughly akin to hue.
There are many color perceptions that by definition cannot be pure spectral colors due to desaturation or because they are purples (mixtures of red and violet light, from opposite ends of the spectrum). Some examples of necessarily non-spectral colors are the achromatic colors (black, gray, and white) and colors such as pink, tan, and magenta.
Two different light spectra that have the same effect on the three color receptors in the human eye will be perceived as the same color. They are metamers of that color. This is exemplified by the white light emitted by fluorescent lamps, which typically has a spectrum of a few narrow bands, while daylight has a continuous spectrum. The human eye cannot tell the difference between such light spectra just by looking into the light source, although the color rendering index of each light source may affect the color of objects illuminated by these metameric light sources.
Similarly, most human color perceptions can be generated by a mixture of three colors called primaries. This is used to reproduce color scenes in photography, printing, television, and other media. There are a number of methods or color spaces for specifying a color in terms of three particular primary colors. Each method has its advantages and disadvantages depending on the particular application.
No mixture of colors, however, can produce a response truly identical to that of a spectral color, although one can get close, especially for the longer wavelengths, where the CIE 1931 color space chromaticity diagram has a nearly straight edge. For example, mixing green light (530 nm) and blue light (460 nm) produces cyan light that is slightly desaturated, because response of the red color receptor would be greater to the green and blue light in the mixture than it would be to a pure cyan light at 485 nm that has the same intensity as the mixture of blue and green.
Because of this, and because the primaries in color printing systems generally are not pure themselves, the colors reproduced are never perfectly saturated spectral colors, and so spectral colors cannot be matched exactly. However, natural scenes rarely contain fully saturated colors, thus such scenes can usually be approximated well by these systems. The range of colors that can be reproduced with a given color reproduction system is called the gamut. The CIE chromaticity diagram can be used to describe the gamut.
Another problem with color reproduction systems is connected with the initial measurement of color, or colorimetry. The characteristics of the color sensors in measurement devices (e.g. cameras, scanners) are often very far from the characteristics of the receptors in the human eye.
A color reproduction system "tuned" to a human with normal color vision may give very inaccurate results for other observers, according to color vision deviations to the standard observer.
The different color response of different devices can be problematic if not properly managed. For color information stored and transferred in digital form, color management techniques, such as those based on ICC profiles, can help to avoid distortions of the reproduced colors. Color management does not circumvent the gamut limitations of particular output devices, but can assist in finding good mapping of input colors into the gamut that can be reproduced.
Additive coloring
Additive color mixing: combining red and green yields yellow; combining all three primary colors together yields white.
Additive color is light created by mixing together light of two or more different colors. Red, green, and blue are the additive primary colors normally used in additive color systems such as projectors, televisions, and computer terminals.
Subtractive coloring
Subtractive color mixing: combining yellow and magenta yields red; combining all three primary colors together yields black.
Twelve main pigment colors
Subtractive coloring uses dyes, inks, pigments, or filters to absorb some wavelengths of light and not others. The color that a surface displays comes from the parts of the visible spectrum that are not absorbed and therefore remain visible. Without pigments or dye, fabric fibers, paint base and paper are usually made of particles that scatter white light (all colors) well in all directions. When a pigment or ink is added, wavelengths are absorbed or "subtracted" from white light, so light of another color reaches the eye.
If the light is not a pure white source (the case of nearly all forms of artificial lighting), the resulting spectrum will appear a slightly different color. Red paint, viewed under blue light, may appear black. Red paint is red because it scatters only the red components of the spectrum. If red paint is illuminated by blue light, it will be absorbed by the red paint, creating the appearance of a black object.
The subtractive model also predicts the color resulting from a mixture of paints, or similar medium such as fabric dye, whether applied in layers or mixed together prior to application. In the case of paint mixed before application, incident light interacts with many different pigment particles at various depths inside the paint layer before emerging.
Structural color
Further information: Structural coloration and Animal coloration
Structural colors are colors caused by interference effects rather than by pigments. Color effects are produced when a material is scored with fine parallel lines, formed of one or more parallel thin layers, or otherwise composed of microstructures on the scale of the color's wavelength. If the microstructures are spaced randomly, light of shorter wavelengths will be scattered preferentially to produce Tyndall effect colors: the blue of the sky (Rayleigh scattering, caused by structures much smaller than the wavelength of light, in this case, air molecules), the luster of opals, and the blue of human irises. If the microstructures are aligned in arrays, for example, the array of pits in a CD, they behave as a diffraction grating: the grating reflects different wavelengths in different directions due to interference phenomena, separating mixed "white" light into light of different wavelengths. If the structure is one or more thin layers then it will reflect some wavelengths and transmit others, depending on the layers' thickness.
Structural color is studied in the field of thin-film optics. The most ordered or the most changeable structural colors are iridescent. Structural color is responsible for the blues and greens of the feathers of many birds (the blue jay, for example), as well as certain butterfly wings and beetle shells. Variations in the pattern's spacing often give rise to an iridescent effect, as seen in peacock feathers, soap bubbles, films of oil, and mother of pearl, because the reflected color depends upon the viewing angle. Numerous scientists have carried out research in butterfly wings and beetle shells, including Isaac Newton and Robert Hooke. Since 1942, electron micrography has been used, advancing the development of products that exploit structural color, such as "photonic" cosmetics.
Cultural perspective
Colors, their meanings and associations can play a major role in works of art, including literature.
Associations
Individual colors have a variety of cultural associations such as national colors (in general described in individual color articles and color symbolism). The field of color psychology attempts to identify the effects of color on human emotion and activity. Chromotherapy is a form of alternative medicine attributed to various Eastern traditions. Colors have different associations in different countries and cultures.
Different colors have been demonstrated to have effects on cognition. For example, researchers at the University of Linz in Austria demonstrated that the color red significantly decreases cognitive functioning in men. The combination of the colors red and yellow together can induce hunger, which has been capitalized on by a number of chain restaurants.
Color plays a role in memory development too. A photograph that is in black and white is slightly less memorable than one in color. Studies also show that wearing bright colors makes you more memorable to people you meet.
Terminology
Main article: Color term
See also: Lists of colors and Web colors
Colors vary in several different ways, including hue (shades of red, orange, yellow, green, blue, and violet, etc), saturation, brightness. Some color words are derived from the name of an object of that color, such as "orange" or "salmon", while others are abstract, like "red".
In the 1969 study Basic Color Terms: Their Universality and Evolution, Brent Berlin and Paul Kay describe a pattern in naming "basic" colors (like "red" but not "red-orange" or "dark red" or "blood red", which are "shades" of red). All languages that have two "basic" color names distinguish dark/cool colors from bright/warm colors. The next colors to be distinguished are usually red and then yellow or green. All languages with six "basic" colors include black, white, red, green, blue, and yellow. The pattern holds up to a set of twelve: black, gray, white, pink, red, orange, yellow, green, blue, purple, brown, and azure (distinct from blue in Russian and Italian, but not English).
See also
Chromophore
Color analysis
Color in Chinese culture
Color mapping
Complementary colors
Impossible color
International Color Consortium
International Commission on Illumination
Lists of colors (compact version)
Neutral color
Pearlescent coating including Metal effect pigments
Pseudocolor
Primary, secondary and tertiary colors | biology | 343 | https://sv.wikipedia.org/wiki/CMYK | CMYK | CMYK är en färgmodell för fyrfärgstryck. Förkortningen står för de i den subtraktiva färgblandningen använda primärfärgerna Cyan, Magenta och gul (Yellow), med tillägg av svart (Key colour) för tillräcklig svärta.
Fyrfärgstryck
CMYK-modellen används vid blandning av färg som läggs på papper eller annat material, det vill säga synliggörs genom reflekterat ljus där de återgivna färgerna beror på absorption av delar av det reflekterade ljusets färgspektrum. Till exempel ger en blandning av gul färg, som absorberar blått, och magenta, som absorberar grönt, en röd färg. Detta kallas subtraktiv färgblandning. Vid tryckning förutsätter detta att de olika färgskikten är transparenta.
Som bildbetraktare kan man därutöver, som i alla bilder, uppleva en typ av optisk färgblandning, på engelska i detta fall kallad additive-averaging mixing (till skillnad från additive mixing, additiv färgblandning), då tillräckligt närliggande färgpunkter upplevs som en samlad färgpunkt i en tredje, blandad färg. För att åstadkomma ett stort färgomfång (colour gamut) i bilden använder trycktekniken en kombination av subtraktiv blandning, där punkterna överlappar varandra, och optisk blandning, där olikfärgade punkter trycks bredvid varandra.
I teorin skulle en blandning av lika delar av de tre primärfärgerna cyan, magenta och gul bli svart, men i praktiken blir det en mörkgrå ton. För att få god svärta, och god skärpa i text, så används vid tryck även svart färg. Ett ekonomiskt motiv för den fjärde färgen är att det går åt mindre bläck att återge mörka ytor när man tillför svart och därmed använder mindre av de tre andra färgerna.
Europaskalan är en färgstandard för offsettryck enligt CMYK-systemet.
RGB och CMYK
Till exempel TV- och datorskärmar arbetar däremot med emitterat ljus och visar färger i RGB-modell, med den additiva färgblandningens tre primärfärger: rött, grönt och blått. En bild skapad i datorns RGB-modell måste därför omarbetas till en CMYK-bild inför utskrift, vilket ofta sker automatiskt genom skrivarens mjukvara, men för vissa tryckarbeten bör man själv förbereda en färdig CMYK-bildfil.
Andra färgsystem för tryck
Det finns färgsystem för tryck med fler än fyra primärfärger. Bland annat:
CcMmYK - 6 färger (cyan, ljus cyan, magenta, ljus magenta, gul och svart)
Pantone Matching System - varierande antal färger
Processfärg
En processfärg är en färg som skapas genom att CMYK-färgerna cyan, magenta, gul och svart blandas.
Se även
Färgsystem
Trefärgstryck
Rasterbild
Dekorfärg
Referenser
Externa länkar
Tryckteknik
Färgsystem och färgrymder | swedish | 0.40138 |
evolutionary_advantage_of_red-green_color_blindness/Green.txt |
Green is the color between cyan and yellow on the visible spectrum. It is evoked by light which has a dominant wavelength of roughly 495–570 nm. In subtractive color systems, used in painting and color printing, it is created by a combination of yellow and cyan; in the RGB color model, used on television and computer screens, it is one of the additive primary colors, along with red and blue, which are mixed in different combinations to create all other colors. By far the largest contributor to green in nature is chlorophyll, the chemical by which plants photosynthesize and convert sunlight into chemical energy. Many creatures have adapted to their green environments by taking on a green hue themselves as camouflage. Several minerals have a green color, including the emerald, which is colored green by its chromium content.
During post-classical and early modern Europe, green was the color commonly associated with wealth, merchants, bankers, and the gentry, while red was reserved for the nobility. For this reason, the costume of the Mona Lisa by Leonardo da Vinci and the benches in the British House of Commons are green while those in the House of Lords are red. It also has a long historical tradition as the color of Ireland and of Gaelic culture. It is the historic color of Islam, representing the lush vegetation of Paradise. It was the color of the banner of Muhammad, and is found in the flags of nearly all Islamic countries.
In surveys made in American, European, and Islamic countries, green is the color most commonly associated with nature, life, health, youth, spring, hope, and envy. In the European Union and the United States, green is also sometimes associated with toxicity and poor health, but in China and most of Asia, its associations are very positive, as the symbol of fertility and happiness. Because of its association with nature, it is the color of the environmental movement. Political groups advocating environmental protection and social justice describe themselves as part of the Green movement, some naming themselves Green parties. This has led to similar campaigns in advertising, as companies have sold green, or environmentally friendly, products. Green is also the traditional color of safety and permission; a green light means go ahead, a green card permits permanent residence in the United States.
Etymology and linguistic definitions
The word green has the same Germanic root as the words for grass and grow
The word green comes from the Middle English and Old English word grene, which, like the German word grün, has the same root as the words grass and grow. It is from a Common Germanic *gronja-, which is also reflected in Old Norse grænn, Old High German gruoni (but unattested in East Germanic), ultimately from a PIE root *ghre- "to grow", and root-cognate with grass and to grow.
The first recorded use of the word as a color term in Old English dates to ca. AD 700.
Latin with viridis also has a genuine and widely used term for "green". Related to virere "to grow" and ver "spring", it gave rise to words in several Romance languages, French vert, Italian verde (and English vert, verdure etc.). Likewise the Slavic languages with zelenъ. Ancient Greek also had a term for yellowish, pale green – χλωρός, chloros (cf. the color of chlorine), cognate with χλοερός "verdant" and χλόη "chloe, the green of new growth".
Thus, the languages mentioned above (Germanic, Romance, Slavic, Greek) have old terms for "green" which are derived from words for fresh, sprouting vegetation.
However, comparative linguistics makes clear that these terms were coined independently, over the past few millennia, and there is no identifiable single Proto-Indo-European or word for "green". For example, the Slavic zelenъ is cognate with Sanskrit harithah "yellow, ochre, golden".
The Turkic languages also have jašɨl "green" or "yellowish green", compared to a Mongolian word for "meadow".
Languages where green and blue are one color
Main articles: Blue–green distinction in language and Color term
The notion of "green" in modern European languages corresponds to about 520–570 nm, but many historical and non-European languages make other choices, e.g. using a term for the range of ca. 450–530 nm ("blue/green") and another for ca. 530–590 nm ("green/yellow").
In some languages, including old Chinese, Thai, old Japanese, and Vietnamese, the same word can mean either blue or green. The Chinese character 青 (pronounced qīng in Mandarin, ao in Japanese, and thanh in Sino-Vietnamese) has a meaning that covers both blue and green; blue and green are traditionally considered shades of "青". In more contemporary terms, they are 藍 (lán, in Mandarin) and 綠 (lǜ, in Mandarin) respectively. Japanese also has two terms that refer specifically to the color green, 緑 (midori, which is derived from the classical Japanese descriptive verb midoru "to be in leaf, to flourish" in reference to trees) and グリーン (guriin, which is derived from the English word "green"). However, in Japan, although the traffic lights have the same colors as other countries have, the green light is described using the same word as for blue, aoi, because green is considered a shade of aoi; similarly, green variants of certain fruits and vegetables such as green apples, green shiso (as opposed to red apples and red shiso) will be described with the word aoi. Vietnamese uses a single word for both blue and green, xanh, with variants such as xanh da trời (azure, lit. "sky blue"), lam (blue), and lục (green; also xanh lá cây, lit. "leaf green").
"Green" in modern European languages corresponds to about 520–570 nm, but many historical and non-European languages make other choices, e.g. using a term for the range of ca. 450–530 nm ("blue/green") and another for ca. 530–590 nm ("green/yellow"). In the comparative study of color terms in the world's languages, green is only found as a separate category in languages with the fully developed range of six colors (white, black, red, green, yellow, and blue), or more rarely in systems with five colors (white, red, yellow, green, and black/blue). These languages have introduced supplementary vocabulary to denote "green", but these terms are recognizable as recent adoptions that are not in origin color terms (much like the English adjective orange being in origin not a color term but the name of a fruit). Thus, the Thai word เขียว kheīyw, besides meaning "green", also means "rank" and "smelly" and holds other unpleasant associations.
The Celtic languages had a term for "blue/green/grey", Proto-Celtic *glasto-, which gave rise to Old Irish glas "green, grey" and to Welsh glas "blue". This word is cognate with the Ancient Greek γλαυκός "bluish green", contrasting with χλωρός "yellowish green" discussed above.
A dark green rectangle
In modern Japanese, the term for green is 緑, while the old term for "blue/green", blue (青, Ao) now means "blue". But in certain contexts, green is still conventionally referred to as 青, as in blue traffic light (青信号, ao shingō) and blue leaves (青葉, aoba), reflecting the absence of blue-green distinction in old Japanese (more accurately, the traditional Japanese color terminology grouped some shades of green with blue, and others with yellow tones).
In science
sRGB rendering of the spectrum of visible light
Colour
Frequency(THz)
Wavelength(nm)
violet
668–789
380–450
blue
610–668
450–490
cyan
575–610
490–520
green
526–575
520–570
yellow
508–526
570–590
orange
484–508
590–620
red
400–484
620–770
Color vision and colorimetry
In optics, the perception of green is evoked by light having a spectrum dominated by energy with a wavelength of roughly 495–570 nm. The sensitivity of the dark-adapted human eye is greatest at about 507 nm, a blue-green color, while the light-adapted eye is most sensitive about 555 nm, a yellow-green; these are the peak locations of the rod and cone (scotopic and photopic, respectively) luminosity functions.
The perception of greenness (in opposition to redness forming one of the opponent mechanisms in human color vision) is evoked by light which triggers the medium-wavelength M cone cells in the eye more than the long-wavelength L cones. Light which triggers this greenness response more than the yellowness or blueness of the other color opponent mechanism is called green. A green light source typically has a spectral power distribution dominated by energy with a wavelength of roughly 487–570 nm.
Green, blue and red are additive colors. All the colors seen are made by mixing them in different intensities.
Human eyes have color receptors known as cone cells, of which there are three types. In some cases, one is missing or faulty, which can cause color blindness, including the common inability to distinguish red and yellow from green, known as deuteranopia or red-green color blindness.
Green is restful to the eye. Studies show that a green environment can reduce fatigue.
In the subtractive color system, used in painting and color printing, green is created by a combination of yellow and blue, or yellow and cyan; in the RGB color model, used on television and computer screens, it is one of the additive primary colors, along with red and blue, which are mixed in different combinations to create all other colors. On the HSV color wheel, also known as the RGB color wheel, the complement of green is magenta; that is, a color corresponding to an equal mixture of red and blue light (one of the purples). On a traditional color wheel, based on subtractive color, the complementary color to green is considered to be red.
In additive color devices such as computer displays and televisions, one of the primary light sources is typically a narrow-spectrum yellowish-green of dominant wavelength ~550 nm; this "green" primary is combined with an orangish-red "red" primary and a purplish-blue "blue" primary to produce any color in between – the RGB color model. A unique green (green appearing neither yellowish nor bluish) is produced on such a device by mixing light from the green primary with some light from the blue primary.
Lasers
Three green lasers being fired at a single spot in the sky from the Starfire Optical Range
Lasers emitting in the green part of the spectrum are widely available to the general public in a wide range of output powers. Green laser pointers outputting at 532 nm (563.5 THz) are relatively inexpensive compared to other wavelengths of the same power, and are very popular due to their good beam quality and very high apparent brightness. The most common green lasers use diode pumped solid state (DPSS) technology to create the green light.
An infrared laser diode at 808 nm is used to pump a crystal of neodymium-doped yttrium vanadium oxide (Nd:YVO4) or neodymium-doped yttrium aluminium garnet (Nd:YAG) and induces it to emit 281.76 THz (1064 nm). This deeper infrared light is then passed through another crystal containing potassium, titanium and phosphorus (KTP), whose non-linear properties generate light at a frequency that is twice that of the incident beam (563.5 THz); in this case corresponding to the wavelength of 532 nm ("green").
Other green wavelengths are also available using DPSS technology ranging from 501 nm to 543 nm.
Green wavelengths are also available from gas lasers, including the helium–neon laser (543 nm), the Argon-ion laser (514 nm) and the Krypton-ion laser (521 nm and 531 nm), as well as liquid dye lasers. Green lasers have a wide variety of applications, including pointing, illumination, surgery, laser light shows, spectroscopy, interferometry, fluorescence, holography, machine vision, non-lethal weapons, and bird control.
As of mid-2011, direct green laser diodes at 510 nm and 500 nm have become generally available,
although the price remains relatively prohibitive for widespread public use. The efficiency of these lasers (peak 3%) compared to that of DPSS green lasers (peak 35%)
may also be limiting adoption of the diodes to niche uses.
Pigments, food coloring and fireworks
See also: Green pigments
The Chicago River is dyed green every year to mark St. Patrick's Day
Many minerals provide pigments which have been used in green paints and dyes over the centuries. Pigments, in this case, are minerals which reflect the color green, rather that emitting it through luminescent or phosphorescent qualities. The large number of green pigments makes it impossible to mention them all. Among the more notable green minerals, however is the emerald, which is colored green by trace amounts of chromium and sometimes vanadium.
Chromium(III) oxide (Cr2O3), is called chrome green, also called viridian or institutional green when used as a pigment. For many years, the source of amazonite's color was a mystery. Widely thought to have been due to copper because copper compounds often have blue and green colors, the blue-green color is likely to be derived from small quantities of lead and water in the feldspar.
Copper is the source of the green color in malachite pigments, chemically known as basic copper(II) carbonate.
Verdigris is made by placing a plate or blade of copper, brass or bronze, slightly warmed, into a vat of fermenting wine, leaving it there for several weeks, and then scraping off and drying the green powder that forms on the metal. The process of making verdigris was described in ancient times by Pliny. It was used by the Romans in the murals of Pompeii, and in Celtic medieval manuscripts as early as the 5th century AD. It produced a blue-green which no other pigment could imitate, but it had drawbacks: it was unstable, it could not resist dampness, it did not mix well with other colors, it could ruin other colors with which it came into contact, and it was toxic. Leonardo da Vinci, in his treatise on painting, warned artists not to use it. It was widely used in miniature paintings in Europe and Persia in the 16th and 17th centuries. Its use largely ended in the late 19th century, when it was replaced by the safer and more stable chrome green. Viridian, as described above, was patented in 1859. It became popular with painters, since, unlike other synthetic greens, it was stable and not toxic. Vincent van Gogh used it, along with Prussian blue, to create a dark blue sky with a greenish tint in his painting Café Terrace at Night.
Green earth is a natural pigment used since the time of the Roman Empire. It is composed of clay colored by iron oxide, magnesium, aluminum silicate, or potassium. Large deposits were found in the South of France near Nice, and in Italy around Verona, on Cyprus, and in Bohemia. The clay was crushed, washed to remove impurities, then powdered. It was sometimes called Green of Verona.
Mixtures of oxidized cobalt and zinc were also used to create green paints as early as the 18th century.
Cobalt green, sometimes known as Rinman's green or zinc green, is a translucent green pigment made by heating a mixture of cobalt (II) oxide and zinc oxide. Sven Rinman, a Swedish chemist, discovered this compound in 1780.
Green chrome oxide was a new synthetic green created by a chemist named Pannetier in Paris in about 1835. Emerald green was a synthetic deep green made in the 19th century by hydrating chrome oxide. It was also known as Guignet green.
Fireworks typically use barium salts to create green sparks
There is no natural source for green food colorings which has been approved by the US Food and Drug Administration. Chlorophyll, the E numbers E140 and E141, is the most common green chemical found in nature, and only allowed in certain medicines and cosmetic materials.
Quinoline Yellow (E104) is a commonly used coloring in the United Kingdom but is banned in Australia, Japan, Norway and the United States.
Green S (E142) is prohibited in many countries, for it is known to cause hyperactivity, asthma, urticaria, and insomnia.
To create green sparks, fireworks use barium salts, such as barium chlorate, barium nitrate crystals, or barium chloride, also used for green fireplace logs. Copper salts typically burn blue, but cupric chloride (also known as "campfire blue") can also produce green flames. Green pyrotechnic flares can use a mix ratio 75:25 of boron and potassium nitrate. Smoke can be turned green by a mixture: solvent yellow 33, solvent green 3, lactose, magnesium carbonate plus sodium carbonate added to potassium chlorate.
Biology
The chloroplasts of plant cells contain a high concentration of chlorophyll, making them appear green.
Frogs often appear green because dermal iridophores reflect blue light through a yellow upperlayer, filtering the light to be primarily green.
A yellow-naped Amazon parrot, colored green for camouflage in the jungle
The green huntsman spider is green due to the presence of bilin pigments in the spider's hemolymph and tissue fluids
Green is common in nature, as many plants are green because of a complex chemical known as chlorophyll, which is involved in photosynthesis. Chlorophyll absorbs the long wavelengths of light (red) and short wavelengths of light (blue) much more efficiently than the wavelengths that appear green to the human eye, so light reflected by plants is enriched in green.
Chlorophyll absorbs green light poorly because it first arose in organisms living in oceans where purple halobacteria were already exploiting photosynthesis. Their purple color arose because they extracted energy in the green portion of the spectrum using bacteriorhodopsin. The new organisms that then later came to dominate the extraction of light were selected to exploit those portions of the spectrum not used by the halobacteria.
A green mamba
Animals typically use the color green as camouflage, blending in with the chlorophyll green of the surrounding environment. Most fish, reptiles, amphibians, and birds appear green because of a reflection of blue light coming through an over-layer of yellow pigment. Perception of color can also be affected by the surrounding environment. For example, broadleaf forests typically have a yellow-green light about them as the trees filter the light. Turacoverdin is one chemical which can cause a green hue in birds, especially. Invertebrates such as insects or mollusks often display green colors because of porphyrin pigments, sometimes caused by diet. This can causes their feces to look green as well. Other chemicals which generally contribute to greenness among organisms are flavins (lychochromes) and hemanovadin. Humans have imitated this by wearing green clothing as a camouflage in military and other fields. Substances that may impart a greenish hue to one's skin include biliverdin, the green pigment in bile, and ceruloplasmin, a protein that carries copper ions in chelation.
The green huntsman spider is green due to the presence of bilin pigments in the spider's hemolymph (circulatory system fluids) and tissue fluids.
It hunts insects in green vegetation, where it is well camouflaged.
Green eyes
Main article: Eye color § Green
There is no green pigment in green eyes; like the color of blue eyes, it is an optical illusion; its appearance is caused by the combination of an amber or light brown pigmentation of the stroma, given by a low or moderate concentration of melanin, with the blue tone imparted by the Rayleigh scattering of the reflected light.
Nobody is brought into the world with green eyes. An infant has one of two eye hues: dark or blue. Following birth, cells called melanocytes start to discharge melanin, the earthy colored shade, in the child's irises. This begins happening since melanocytes respond to light in time.
Green eyes are most common in Northern and Central Europe.
They can also be found in Southern Europe, West Asia, Central Asia, and South Asia. In Iceland, 89% of women and 87% of men have either blue or green eye color.
A study of Icelandic and Dutch adults found green eyes to be much more prevalent in women than in men.
Among European Americans, green eyes are most common among those of recent Celtic and Germanic ancestry, about 16%.
In history and art
Prehistoric history
Neolithic cave paintings do not have traces of green pigments, but neolithic peoples in northern Europe did make a green dye for clothing, made from the leaves of the birch tree. It was of very poor quality, more brown than green. Ceramics from ancient Mesopotamia show people wearing vivid green costumes, but it is not known how the colors were produced.
Ancient history
The gardens of ancient Egypt were symbols of rebirth. Tomb painting of the gardens of Amon at the temple of Karnak, from the tomb of Nakh, the chief gardener. Early 14th century BC.
The Ancient Egyptian god Osiris, ruler of the underworld and of rebirth and regeneration, was typically shown with a green face. (Tomb of Nefertari, 1295–1253 BC)
Ancient Roman fresco of Flora, or Spring, from Stabiae (2nd century AD)
Gorgan ceramic, Early 13th century
In Ancient Egypt, green was the symbol of regeneration and rebirth, and of the crops made possible by the annual flooding of the Nile. For painting on the walls of tombs or on papyrus, Egyptian artists used finely ground malachite, mined in the west Sinai and the eastern desert; a paintbox with malachite pigment was found inside the tomb of King Tutankhamun. They also used less expensive green earth pigment, or mixed yellow ochre and blue azurite. To dye fabrics green, they first colored them yellow with dye made from saffron and then soaked them in blue dye from the roots of the woad plant.
For the ancient Egyptians, green had very positive associations. The hieroglyph for green represented a growing papyrus sprout, showing the close connection between green, vegetation, vigor and growth. In wall paintings, the ruler of the underworld, Osiris, was typically portrayed with a green face, because green was the symbol of good health and rebirth. Palettes of green facial makeup, made with malachite, were found in tombs. It was worn by both the living and the dead, particularly around the eyes, to protect them from evil. Tombs also often contained small green amulets in the shape of scarab beetles made of malachite, which would protect and give vigor to the deceased. It also symbolized the sea, which was called the "Very Green".
In Ancient Greece, green and blue were sometimes considered the same color, and the same word sometimes described the color of the sea and the color of trees. The philosopher Democritus described two different greens: chloron, or pale green, and prasinon, or leek green. Aristotle considered that green was located midway between black, symbolizing the earth, and white, symbolizing water. However, green was not counted among the four classic colors of Greek painting – red, yellow, black and white – and is rarely found in Greek art.
The Romans had a greater appreciation for the color green; it was the color of Venus, the goddess of gardens, vegetables and vineyards. The Romans made a fine green earth pigment that was widely used in the wall paintings of Pompeii, Herculaneum, Lyon, Vaison-la-Romaine, and other Roman cities. They also used the pigment verdigris, made by soaking copper plates in fermenting wine. By the second century AD, the Romans were using green in paintings, mosaics and glass, and there were ten different words in Latin for varieties of green.
Postclassical history
In the Arnolfini portrait by Jan van Eyck (1434), the rich green fabric of the dress showed the wealth and status of the family.
Duccio di Buoninsegna painted the faces in this painting (1308–1311) with an undercoat of green earth pigment. The surface pink has faded, making the faces look green today.
The green costume of the Mona Lisa shows she was from the gentry, not from the nobility.
In the 15th century Saint Wolfgang and the Devil by Michael Pacher, the Devil is green. Poets such as Chaucer also drew connections between the color green and the devil.
In this 1503 painting by Perugino, malachite pigment was used to paint the bright green garments of the worshippers, while the background greens were painted in green earth pigments.
In the Middle Ages and Renaissance, the color of clothing showed a person's social rank and profession. Red could only be worn by the nobility, brown and gray by peasants, and green by merchants, bankers and the gentry and their families. The Mona Lisa wears green in her portrait, as does the bride in the Arnolfini portrait by Jan van Eyck.
There were no good vegetal green dyes which resisted washing and sunlight for those who wanted or were required to wear green. Green dyes were made out of the fern, plantain, buckthorn berries, the juice of nettles and of leeks, the digitalis plant, the broom plant, the leaves of the fraxinus, or ash tree, and the bark of the alder tree, but they rapidly faded or changed color. Only in the 16th century was a good green dye produced, by first dyeing the cloth blue with woad, and then yellow with Reseda luteola, also known as yellow-weed.
The pigments available to painters were more varied; monks in monasteries used verdigris, made by soaking copper in fermenting wine, to color medieval manuscripts. They also used finely-ground malachite, which made a luminous green. They used green earth colors for backgrounds.
During the early Renaissance, painters such as Duccio di Buoninsegna learned to paint faces first with a green undercoat, then with pink, which gave the faces a more realistic hue. Over the centuries the pink has faded, making some of the faces look green.
Modern history
In the 18th and 19th century
Dedham Vale (1802) by John Constable. The paintings of Constable romanticized the vivid green landscapes of England
In the painting of Jean-Baptiste Debret (1822), Emperor Pedro I of Brazil wearing the imperial mantle decorated with green fabric.
In the paintings of Jean-Baptiste-Camille Corot (1796–1875), the green of trees and nature became the central element of the painting, with the people secondary
Spring, by Marie Bashkirtseff, 1884
The Night Café, (1888), by Vincent van Gogh, used red and green to express what Van Gogh called "the terrible human passions."
Émile Bernard – Still life with green teapot, cup and fruit, 1890
Louis Anquetin – Woman at the Champs-Élysées by night
The 18th and 19th centuries brought the discovery and production of synthetic green pigments and dyes, which rapidly replaced the earlier mineral and vegetable pigments and dyes. These new dyes were more stable and brilliant than the vegetable dyes, but some contained high levels of arsenic, and were eventually banned.
In the 18th and 19th centuries, green was associated with the romantic movement in literature and art. The German poet and philosopher Goethe declared that green was the most restful color, suitable for decorating bedrooms. Painters such as John Constable and Jean-Baptiste-Camille Corot depicted the lush green of rural landscapes and forests. Green was contrasted to the smoky grays and blacks of the Industrial Revolution.
The second half of the 19th century saw the use of green in art to create specific emotions, not just to imitate nature. One of the first to make color the central element of his picture was the American artist James McNeill Whistler, who created a series of paintings called "symphonies" or "noctures" of color, including Symphony in gray and green; The Ocean between 1866 and 1872.
The late 19th century also brought the systematic study of color theory, and particularly the study of how complementary colors such as red and green reinforced each other when they were placed next to each other. These studies were avidly followed by artists such as Vincent van Gogh. Describing his painting, The Night Cafe, to his brother Theo in 1888, Van Gogh wrote: "I sought to express with red and green the terrible human passions. The hall is blood red and pale yellow, with a green billiard table in the center, and four lamps of lemon yellow, with rays of orange and green. Everywhere it is a battle and antithesis of the most different reds and greens."
In the 20th and 21st century
In the 1980s, green became a political symbol, the color of the Green Party in Germany and in many other European countries. It symbolized the environmental movement, and also a new politics of the left which rejected traditional socialism and communism. (See § In politics section below.)
Symbolism and associations
Safety and permission
A green light is the universal symbol of permission to go
Green can communicate safety to proceed, as in traffic lights. Green and red were standardized as the colors of international railroad signals in the 19th century. The first traffic light, using green and red gas lamps, was erected in 1868 in front of the Houses of Parliament in London. It exploded the following year, injuring the policeman who operated it. In 1912, the first modern electric traffic lights were put up in Salt Lake City, Utah. Red was chosen largely because of its high visibility, and its association with danger, while green was chosen largely because it could not be mistaken for red. Today green lights universally signal that a system is turned on and working as it should. In many video games, green signifies both health and completed objectives, opposite red.
Nature, vivacity, and life
Green is the color most commonly associated in Europe and the United States with nature, vivacity and life.
It is the color of many environmental organizations, such as Greenpeace, and of the Green Parties in Europe. Many cities have designated a garden or park as a green space, and use green trash bins and containers. A green cross is commonly used to designate pharmacies in Europe.
In China, green is associated with the east, with sunrise, and with life and growth. In Thailand, the color green is considered auspicious for those born on a Wednesday (light green for those born at night).
Springtime, freshness, and hope
Green is the color most commonly associated in the United States and Europe with springtime, freshness, and hope. Green is often used to symbolize rebirth and renewal and immortality. In Ancient Egypt; the god Osiris, king of the underworld, was depicted as green-skinned. Green as the color of hope is connected with the color of springtime; hope represents the faith that things will improve after a period of difficulty, like the renewal of flowers and plants after the winter season.
Youth and inexperience
Green the color most commonly associated in Europe and the United States with youth. It also often is used to describe anyone young, inexperienced, probably by the analogy to immature and unripe fruit. Examples include green cheese, a term for a fresh, unaged cheese, and greenhorn, an inexperienced person.
Food and diet
Indian FSSAI labels. The green dot symbol (top-left) identifies lacto-vegetarian food.
The color green has been increasingly used by food companies, governments, and practitioners themselves to identify veganism and vegetarianism. The government of India requires food that is vegetarian to be marked with a green circle as part of the Food Safety and Standards Act of 2006 with changes to symbolism since but still maintaining the color green. In 2021, India introduced a green V to exclusively label vegan options. In the west, the V-Label, a green V designed by the European Vegetarian Union, has been used by food distributors to label vegan and vegetarian options.
Calm, tolerance, and the agreeable
Surveys also show that green is the color most associated with the calm, the agreeable, and tolerance. Red is associated with heat, blue with cold, and green with an agreeable temperature. Red is associated with dry, blue with wet, and green, in the middle, with dampness. Red is the most active color, blue the most passive; green, in the middle, is the color of neutrality and calm, sometimes used in architecture and design for these reasons.
Blue and green together symbolize harmony and balance. Experimental studies also show this calming effect in a statistical significant decrease of negative emotions
and increase of creative performance.
Jealousy and envy
Green is often associated with jealousy and envy. The expression "green-eyed monster" was first used by William Shakespeare in Othello: "it is the green-eyed monster which doth mock the meat it feeds on." Shakespeare also used it in the Merchant of Venice, speaking of "green-eyed jealousy".
Love and sexuality
Green today is not commonly associated in Europe and the United States with love and sexuality, but in stories of the medieval period it sometimes represented love and the base, natural desires of man. It was the color of the serpent in the Garden of Eden who caused the downfall of Adam and Eve. However, for the troubadours, green was the color of growing love, and light green clothing was reserved for young women who were not yet married.
In Persian and Sudanese poetry, dark-skinned women, called "green" women, were considered erotic. The Chinese term for cuckold is "to wear a green hat." This was because in ancient China, prostitutes were called "the family of the green lantern" and a prostitute's family would wear a green headscarf.
In Victorian England, the color green was associated with homosexuality.
Dragons, fairies, monsters, and devils
Saint Wolfgang and the Devil, by Michael Pacher.
A medieval illustration of a dragon (1460)
A Chinese dragon dance
A 20th-century depiction of a leprechaun
In legends, folk tales and films, fairies, dragons, monsters, and the devil are often shown as green.
In the Middle Ages, the devil was usually shown as either red, black or green. Dragons were usually green, because they had the heads, claws and tails of reptiles.
Modern Chinese dragons are also often green, but unlike European dragons, they are benevolent; Chinese dragons traditionally symbolize potent and auspicious powers, particularly control over water, rainfall, hurricane, and floods. The dragon is also a symbol of power, strength, and good luck. The Emperor of China usually used the dragon as a symbol of his imperial power and strength. The dragon dance is a popular feature of Chinese festivals.
In Irish and English folklore, the color was sometimes associated with witchcraft, and with faeries and spirits. The type of Irish fairy known as a leprechaun is commonly portrayed wearing a green suit, though before the 20th century he was usually described as wearing a red suit.
In theater and film, green was often connected with monsters and the inhuman. The earliest films of Frankenstein were in black and white, but in the poster for the 1935 version The Bride of Frankenstein, the monster had a green face. Actor Bela Lugosi wore green-hued makeup for the role of Dracula in the 1927–1928 Broadway stage production.
Poison and sickness
Like other common colors, green has several completely opposite associations. While it is the color most associated by Europeans and Americans with good health, it is also the color most often associated with toxicity and poison. There was a solid foundation for this association; in the nineteenth century several popular paints and pigments, notably verdigris, vert de Schweinfurt and vert de Paris, were highly toxic, containing copper or arsenic. The intoxicating drink absinthe was known as "the green fairy".
A green tinge in the skin is sometimes associated with nausea and sickness. The expression 'green at the gills' means appearing sick. The color, when combined with gold, is sometimes seen as representing the fading of youth. In some Far East cultures the color green is used as a symbol of sickness or nausea.
Social status, prosperity and the dollar
The green benches in the House of Commons of the United Kingdom
The reverse of the United States one-dollar bill has been green since 1861, giving it the popular name greenback.
Green in Europe and the United States is sometimes associated with status and prosperity. From the Middle Ages to the 19th century it was often worn by bankers, merchants country gentlemen and others who were wealthy but not members of the nobility. The benches in the House of Commons of the United Kingdom, where the landed gentry sat, are colored green.
In the United States green was connected with the dollar bill. Since 1861, the reverse side of the dollar bill has been green. Green was originally chosen because it deterred counterfeiters, who tried to use early camera equipment to duplicate banknotes. Also, since the banknotes were thin, the green on the back did not show through and muddle the pictures on the front of the banknote. Green continues to be used because the public now associates it with a strong and stable currency.
One of the more notable uses of this meaning is found in The Wonderful Wizard of Oz. The Emerald City in this story is a place where everyone wears tinted glasses that make everything appear green. According to the populist interpretation of the story, the city's color is used by the author, L. Frank Baum, to illustrate the financial system of America in his day, as he lived in a time when America was debating the use of paper money versus gold.
On flags
The flag of Italy (1797) was modeled after the flag of France. It was originally the flag of the Cisalpine Republic, and the green came from the uniforms of the army of Milan.
The flag of Brazil (1889). The green color was inherited from the flag of the Empire of Brazil, where it represented the color of the House of Braganza.
The flag of Lithuania (1918). The green represents the beauty of nature, freedom and hope.
The flag of Ireland (1919). The green represents the culture and traditions of Gaelic Ireland.
The Flag of Saudi Arabia (1932) has the green color of Islam. The inscription in Arabic says: "There is no God but Allah, and Muhammad is his Prophet."
The flag of India (1947). The green has been said at different times to represent hope, or prosperity.
The flag of Bangladesh (1971). The green field stands for the lushness of the land of Bangladesh
The flag of Nigeria (1960). The green represents the forests and natural wealth of the country.
The flag of Pakistan (1947). The green part represents the Muslim majority of the country.
The flag of South Africa (1994) includes green, yellow and black, the colors of the African National Congress.
The former flag of Libya (1977–2011) was the only flag in the world with a single color and no design or details.
The flag of Italy (1797) was modeled after the French tricolor. It was originally the flag of the Cisalpine Republic, whose capital was Milan; red and white were the colors of Milan, and green was the color of the military uniforms of the army of the Cisalpine Republic. Other versions say it is the color of the Italian landscape, or symbolizes hope.
The flag of Brazil has a green field adapted from the flag of the Empire of Brazil. The green represented the royal family.
The flag of India was inspired by an earlier flag of the independence movement of Gandhi, which had a red band for Hinduism and a green band representing Islam, the second largest religion in India.
The flag of Pakistan symbolizes Pakistan's commitment to Islam and equal rights of religious minorities where the larger portion (3:2 ratio) of flag is dark green representing Muslim majority (98% of total population) while a white vertical bar (3:1 ratio) at the mast representing equal rights for religious minorities and minority religions in country. The crescent and star symbolizes progress and bright future respectively.
The flag of Bangladesh has a green field based on a similar flag used during the Bangladesh Liberation War of 1971. It consists of a red disc on top of a green field. The red disc represents the sun rising over Bengal, and also the blood of those who died for the independence of Bangladesh. The green field stands for the lushness of the land of Bangladesh.
The flag of the international constructed language Esperanto has a green field and a green star in a white area. The green represents hope ("esperanto" means "one who hopes"), the white represents peace and neutrality and the star represents the five inhabited continents.
Green is one of the three colors (along with red and black, or red and gold) of Pan-Africanism. Several African countries thus use the color on their flags, including Nigeria, South Africa, Ghana, Senegal, Mali, Ethiopia, Togo, Guinea, Benin, and Zimbabwe. The Pan-African colors are borrowed from the Ethiopian flag, one of the oldest independent African countries. Green on some African flags represents the natural richness of Africa.
Many flags of the Islamic world are green, as the color is considered sacred in Islam (see below). The flag of Hamas, as well as the flag of Iran, is green, symbolizing their Islamist ideology. The 1977 flag of Libya consisted of a simple green field with no other characteristics. It was the only national flag in the world with just one color and no design, insignia, or other details. Some countries used green in their flags to represent their country's lush vegetation, as in the flag of Jamaica, and hope in the future, as in the flags of Portugal and Nigeria. The green cedar of Lebanon tree on the Flag of Lebanon officially represents steadiness and tolerance.
Wikisource has original text related to this article:
The Wearing of the Green
Green is a symbol of Ireland, which is often referred to as the "Emerald Isle". The color is particularly identified with the republican and nationalist traditions in modern times. It is used this way on the flag of the Republic of Ireland, in balance with white and the Protestant orange. Green is a strong trend in the Irish holiday St. Patrick's Day.
In politics
See also: Green politics
The green harp flag was the banner of Irish nationalism from the 17th century until the early 20th century.
The emblem of the Australian Greens. The party won 12.7% of the primary vote in the 2022 election for the Australian Senate.
A demonstration by Les Verts, the green party of France, in Lyon.
The Rainbow Warrior, the ship of the Greenpeace environmental movement.
The logo of the Crescent Star Party uses star and crescent symbol with green background.
The first recorded green party was a political faction in Constantinople during the 6th century Byzantine Empire. which took its name from a popular chariot racing team. They were bitter opponents of the blue faction, which supported Emperor Justinian I and which had its own chariot racing team. In 532 AD rioting between the factions began after one race, which led to the massacre of green supporters and the destruction of much of the center of Constantinople. (See Nika Riots).
Green was the traditional color of Irish nationalism, beginning in the 17th century. The green harp flag, with a traditional gaelic harp, became the symbol of the movement. It was the banner of the Society of United Irishmen, which organized the ultimately unsuccessful Irish Rebellion of 1798. When Ireland achieved independence in 1922, green was incorporated into the national flag.
In the 1970s, green became the color of the third biggest Swiss Federal Council political party, the Swiss People's Party SVP. The ideology is Swiss nationalism, national conservatism, right-wing populism, economic liberalism, agrarianism, isolationism, euroscepticism. The SVP was founded on September 22, 1971 and has 90,000 members.
In the 1980s, green became the color of a number of new European political parties organized around an agenda of environmentalism. Green was chosen for its association with nature, health, and growth. The largest green party in Europe is Alliance '90/The Greens (German: Bündnis 90/Die Grünen) in Germany, which was formed in 1993 from the merger of the German Green Party, founded in West Germany in 1980, and Alliance 90, founded during the Revolution of 1989–1990 in East Germany. In the 2009 federal elections, the party won 11% of the votes and 68 out of 622 seats in the Bundestag.
Green parties in Europe have programs based on ecology, grassroots democracy, nonviolence, and social justice. Green parties are found in over one hundred countries, and most are members of the Global Green Network.
Greenpeace is a non-governmental environmental organization which emerged from the anti-nuclear and peace movements in the 1970s. Its ship, the Rainbow Warrior, frequently tried to interfere with nuclear tests and whaling operations. The movement now has branches in forty countries.
The Australian Greens was founded in 1992. In the 2010 federal election, the party received 13% of the vote (more than 1.6 million votes) in the Senate, a first for any Australian minor party.
Green is the color associated with Puerto Rico's Independence Party, the smallest of that country's three major political parties, which advocates Puerto Rican independence from the United States.
In Indonesia, green is used by several Islamist political party, including National Awakening Party, Crescent Star Party, United Development Party, and the local Aceh Just and Prosperous Party.
In Taiwan, green is used by Democratic Progressive Party. Green in Taiwan associates with Taiwan independence movement.
In religion
See also: Green in Islam
Green is the traditional color of Islam. According to tradition, the robe and banner of Muhammad were green, and according to the Koran (XVIII, 31 and LXXVI, 21) those fortunate enough to live in paradise wear green silk robes. Muhammad is quoted in a hadith as saying that "water, greenery, and a beautiful face" were three universally good things. Green was accordingly adopted as a Shi'a color.
Al-Khidr ("The Green One"), was an important Qur'anic figure who was said to have met and traveled with Moses. He was given that name because of his role as a diplomat and negotiator. Green was also considered to be the median color between light and obscurity.
Roman Catholic and more traditional Protestant clergy wear green vestments at liturgical celebrations during Ordinary Time. In the Eastern Catholic Church, green is the color of Pentecost. Green is one of the Christmas colors as well, possibly dating back to pre-Christian times, when evergreens were worshiped for their ability to maintain their color through the winter season. Romans used green holly and evergreen as decorations for their winter solstice celebration called Saturnalia, which eventually evolved into a Christmas celebration. In Ireland and Scotland especially, green is used to represent Catholics, while orange is used to represent Protestantism. This is shown on the national flag of Ireland.
In Paganism, green represents abundance, growth, wealth, renewal, and balance. In magickal practices, green is often used to bring money and luck. One figure who shares parallels with various deities is the Green Man.
In gambling and sports
A green belt in judo.
A baccarat palette and cards on a casino gambling table.
A 1929 Bentley colored British racing green.
A billiards table, colored green after the lawns where the ancestors of the game were originally played.
Gambling tables in a casino are traditionally green. The tradition is said to have started in gambling rooms in Venice in the 16th century.
Billiards tables are traditionally covered with green woolen cloth. The first indoor tables, dating to the 15th century, were colored green after the grass courts used for the similar lawn games of the period.
Green was the traditional color worn by hunters in the 19th century, particularly the shade called hunter green. In the 20th century most hunters began wearing the color olive drab, a shade of green, instead of hunter green.
Green is a common color for sports teams. Well-known teams include A.S. Saint-Étienne of France, known as Les Verts (The Greens). The Green Bay Packers, an American football team, has the color in its official name and wears green uniforms. A number of national soccer teams feature the color, with the color usually reflective of the teams' national flag.
British racing green was the international motor racing color of Britain from the early 1900s until the 1960s, when it was replaced by the colors of the sponsoring automobile companies.
A green belt in karate, taekwondo, and judo symbolizes a level of proficiency in the sport.
Idioms and expressions
Having a green thumb (American English) or green fingers (British English). To be passionate about or talented at gardening. The expression was popularized beginning in 1925 by a BBC gardening program.
Greenhorn. Someone who is inexperienced.
Green-eyed monster. Refers to jealousy. (See section above on jealousy and envy).
Greenmail. A term used in finance and corporate takeovers. It refers to the practice of a company paying a high price to buy back shares of its own stock to prevent an unfriendly takeover by another company or businessman. It originated in the 1980s on Wall Street, and originates from the green of dollars.
Green room. A room at a theater where actors rest when not onstage, or a room at a television studio where guests wait before going on-camera. It originated in the late 17th century from a room of that color at the Theatre Royal, Drury Lane in London.
Greenwashing. Environmental activists sometimes use this term to describe the advertising of a company which promotes its positive environmental practices to cover up its environmental destruction.
Green around the gills. A description of a person who looks physically ill.
Going green. An expression commonly used to refer to preserving the natural environment, and participating in activities such as recycling materials.
Looking green. A description of a person who looks revolted or repulsed.
Notes
^ The sRGB values are taken by converting the NCS color 2060-G using the "NCS Navigator" tool at the NCS website.
^
More specifically, "blue green" 487–493 nm, "bluish green" 493–498 nm, "green" 498–530 nm, "yellowish green" 530–559 nm, "yellow green" 559–570 nm Kelly (1943).
^ 62 percent of respondents surveyed associated green with springtime, (18 percent choosing yellow); 27 percent associated green with freshness (24 percent choosing blue.) 48 percent associated green with hope (18 percent choosing blue)
^ 22 percent of respondents surveyed associated green with youth, (16 percent choosing yellow)
^
For an example of the use of green in archectecture, see the article on the University of Technology, Sydney Science Faculty building.
^ In a survey cited, 45 percent of respondents associated green with toxicity, while 20 percent associated yellow.
See also
Arts portalChemistry portalGardening portal
Shades of green
Green pigments
| biology | 24539 | https://sv.wikipedia.org/wiki/Gr%C3%B6n | Grön | Grön är en av de traditionella spektralfärgerna och det gröna färgområdet omfattar en mängd olika gröna nyanser. I det standardiserade färgbeteckningssystemet NCS är grön en av sex elementarfärger och har beteckningen G. I RGB-systemet för additiv färgblandning är grön (G) en av de tre primärfärgerna. Grönt är den dominerande färgen i levande vegetation och har symboliska betydelser som ofta har att göra med naturen.
Definition
Många forskare uttrycker en grundläggande svårighet att alls definiera vad färg ÄR och färgordet "grön" har ingen entydig betydelse utan definieras olika inom olika vetenskapsgrenar och även av olika forskare inom samma vetenskapsgren. Arne Valberg, professor i biofysik, menar att färger är uppenbara fakta (sinnesdata) som inte kan förnekas, men att de, liksom andra kvalitativa upplevelser inte har några fysiska motsvarigheter. C.L. Hardin, professor i filosofi skiljer på motsvarande sätt mellan fysikalisk färg och uppfattad färg, och menar att vardagsspråkets färgord bör reserveras för färger så som vi ser dem.
I denna artikel används olika definitioner i olika avsnitt. I de flesta fall framgår det av sammanhanget vilken definition som används, och annars anges det i respektive avsnitt.
Definition utifrån språkbruk
Ett sätt att definiera "grön" utgår från hur ordet används i svenska språket. I detta fall är grön ett färgområde, inte en specifik färg. Ordet grön används för en mängd olika färger med sinsemellan mycket olika karaktär, från ljusgrön till mörkgrön, från grågrön till knallgrön och från blåaktigt grön till gulaktigt grön. Färgnamnet grön syftar på ett stort spann av kulörtoner och kan användas oavsett om färgen är ljus eller mörk, gråaktig eller intensiv. Därmed täcker det in en större del av färgvärlden än något annat färgnamn. Även i de flesta andra språk täcker ordet för grön ett betydligt större färgområde än orden för gul och röd. Gränserna mellan de färgområden som benämns med respektive färgord är flytande, varierar med situationen och individen och kan förändras över tiden.
Definition utifrån våglängd hos monokromatiskt ljus
En annan definition utgår från vilka strålningsvåglängder av monokromatiskt ljus som får människor att se gröna färger i de mycket speciella situationer där man bara ser en våglängd i taget. Även här handlar det om ett färgområde som inte har någon exakt avgränsning. Spektrum utgörs av en kontinuerlig övergång mellan olika våglängder, och det finns inget allmänt vedertaget sätt att dela in det i olika färger. Ett av många förslag till indelning visas i boxen härintill, som också visar strålningens frekvens uttryckt i terahertz (THz). Det våglängdsspann som kallas grönt varierar mellan olika källor, och kan som mest sträcka sig mellan c:a 490 och 575 nanometer (nm). Strålning med närmast längre våglängd ger gul färg, och den färg som ges av strålning med närmast kortare våglängd benämns i olika källor cyan eller blå.
Ett annat sätt att definiera grönt utifrån spektrum är att ange en ungefärlig våglängd som motsvarar en typisk grön. Inte heller här finns någon allmänt vedertagen definition. De våglängder som anges kan variera mellan ungefär 510 och 550 nm, men källorna är noga med att understryka att dessa angivelser endast är ungefärliga och beror på en rad omständigheter.
Olika definitioner i olika tillämpningar
I olika färgbeskrivningsmodeller och tillämpningar finns ett antal färger som utgör just den modellens/tillämpningens utgångspunkt vad gäller "grön". De definieras utifrån olika utgångspunkter och är inte samma gröna färg, och ingen av dem gör anspråk på att vara den enda och sanna gröna - i stället kallas de "den gröna elementarfärgen", "den gröna grundfärgen" etc.
Några exempel:
- I opponentfärgsteorin, som är den allmänt accepterade teorin om människans färgseende, är grön en av de fyra unika kulörtonerna och karakteriseras att den varken är blåaktig eller gulaktig. För varje person finns ett smalt våglängdsområde i spektrum som motsvarar personens uppfattning av unikt grönt, men vilka våglängder det handlar om varierar från individ till individ. Vilka processer i hjärnan som får oss att se dessa färger som unika är ännu inte klarlagt.
- I det i Sverige standardiserade färgbeteckningssystemet NCS (Natural Colour System) är Grön (G) en av sex elementarfärger och definieras som den färg som inte har någon visuell likhet med gult, rött, blått, vitt eller svart. Denna definition utgår alltså helt från färgperception. Den gröna elementarfärgen är imaginär i betydelsen att den representerar föreställningen om en ideal färg och finns inte specificerad i form av färgprov eller fysiska mätvärden. I NCS färgatlas visas ett antal färgprover som under standardiserade betraktningsförhållanden, och med hopvägning av många observatörers bedömningar, har samma uppfattade kulörton men inte är lika rena som den gröna elementarfärgen. Deras tristimulusvärden och trikromatiska koordinater med hänvisning till CIE finns publicerade i tabellform.
- I det amerikanska färgsystemet Munsell Book of Color är Green en av fem grundläggande kulörtoner (principal hues), och definieras med kolorimetriska värden. Munsell-systemets gröna grundfärg överensstämmer relativt väl med NCS-systemets gröna elementarfärg.
- I RGB-systemet för additiv färgblandning är Grön (G) en av de tre primärfärgerna, men exakt vilken grön färg som avses kan variera mellan olika tillämpningar. I den standardiserade RGB-färgrymden sRGB, skapad för användning på bildskärmar och internet, definieras de tre primärfärgerna med hänvisning till CIE:s tristimulusvärden (CIE XYZ). De matematiska formlerna för detta varierar något mellan olika källor.
- En av de 16 originalfärgerna för HTML 4.01, det system som specificerar och benämner färger för användning på internet, har namnet Green och en annan har namnet Lime. Deras koordinater visas i boxarna härintill. Lime motsvarar den gröna primärfärgen i sRGB.
Grönt i naturen
När vårt öga nås av ljus med en våglängd kring 540 nanometer ser vi i normalfallet en grön färg. Det är också i detta våglängdsområde som det mänskliga synsinnet är som känsligast, alltså uppfattar mest ljus i förhållande till strålningens energi. Strålning med bara en våglängd (monokromatiskt ljus) förekommer dock bara i specialfall, som till exempel regnbågen, och normalt sett är det en blandning av många olika våglängder som får oss att se en grön färg.
Hos levande vegetation är grönt den absolut vanligaste färgen. Det gröna pigmentet klorofyll spelar en avgörande roll i växternas fotosyntes, alltså omvandlingen av oorganiskt kol från luftens koldioxid till organiskt kol i växtvävnaden. De typiskt klorofyllgröna färgerna har en tydlig gulaktighet, med kulörtoner mellan NCS G40Y och G50Y. Många mindre djur har gröna färger som liknar vegetationens, vilket tjänar som kamouflage och därmed skydd mot rovdjur.
Grön färg i fjäderdräkten hos fåglar orsakas ofta genom samverkan av gula pigment och blå så kallade strukturfärger, som orsakas av fjädrarnas uppbyggnad. Strukturfärgerna uppstår genom interferens mellan strålningsvågor som reflekteras eller sprids från ytor som ligger på olika nivåer, mycket nära varandra.
Grönt är ovanligt i berggrunden och gröna mineral som till exempel smaragd eller malakit används till smycken och prydnadsföremål eller i mald form som pigment.
Gröna pigment och färgämnen
Bland de växt- och djurbaserade färgämnen som traditionellt har använts för färgning av textilier finns inget som ger en hållbar grön färg. För att åstadkomma grönt har man därför varit tvungen att färga först gult och sedan blått. Detta ändrades först på 1800-talet, när man började producera syntetiska färgämnen.
För måleri har man i äldre tid hämtat pigment ur jorden eller krossat mineraler. Grönjord är oftast relativt kulörsvag men var länge ett av de vanligaste gröna pigmenten. Grön umbra är, namnet till trots, snarare varmgrå än grön. För starkare gröna färger har man åtminstone sedan medeltiden använt krossad malakit. Man har också, ända sedan antiken, tillverkat det gröna pigmentet spanskgrönt (verdigris). Under 1800-talet började man tillverka nya oorganiska pigment, ofta baserade på det nyupptäckta grundämnet krom (kromgrönt, kromoxidgrönt, smaragdgrönt). Även arsenik förekom, exempelvis i schweinfurtergrönt. Sedan mitten på 1900-talet har de flesta av de äldre gröna pigmenten ersatts av ftalocyaninfärgämnen. Ftalocyaningrönt är (2010) det enda gröna pigment som normalt ingår i färgtillverkarnas brytsystem.
För blandning av pigment finns flera olika uppsättningar av tre grundfärger eller primärfärger som tillsammans med svart och vitt antagits räcka till för att åstadkomma alla andra färger. Den traditionella uppsättningen med ett rött, ett gult och ett blått pigment blev kodifierad kring år 1600. Grönt åstadkoms i detta fall genom blandning av gult och blått pigment, då det sker en överlappning i den gröna delen av spektrumet hos det reflekterade ljuset från de båda pigmenten.
Grönt i tryckning och digital teknik
I CMYK-systemet för tryckning är grön en sekundärfärg, som åstadkoms genom blandning av primärfärgerna gult och cyan. CMYK och RGB är anpassade till varandra så att den gröna sekundärfärgen i CMYK åtminstone i teorin motsvarar den gröna primärfärgen i RGB.
Bland X11-färgerna för bildskärmar finns ett tjugotal färger som i dagligt tal kan kallas gröna eller har engelska namn som slutar på "green". Nedan anges även deras hexadecimala RGB-kod.
Etymologi
Ordet grön finns redan i fornsvenskan och dess ursprung kan härledas ur den germanska språkstammen gro (växa). Ordet grön kan därmed tolkas som med gräsfärg. I fornsvenskan hade ordet också betydelsen frisk (om sår m.m.), och åtminstone sedan 1600-talet i den överförda betydelsen omogen. Gröna gatan och liknande gatunamn i Danmark, Skåne och Västsverige syftade ursprungligen på att gatorna var nya och ännu inte färdigbyggda.
I de romanska språken har ordet för grönt utvecklats från latinets viride, som samtidigt har en ursprunglig betydelse av "livskraft".
Historik
Människor i den neolitiska forntidens Europa tillverkade grönbrun färg av björklöv för att färga kläder, och i det forntida Mesopotamien har återfunnits grönfärgad keramik.
Grönt var en populär färg i det forntida Egypten, där det associerades med återfödelse och användes i målningar, textilier och kosmetika.
Antikens greker ansåg att grönt och blått var samma färg och det är därför svårt att avgöra hur ofta dessa färger användes av grekerna: de fyra huvudfärgerna inom grekiskt måleri var dock rött, gult, svart och vitt, och grönt och blått tycks sällan ha använts inom grekisk konst.
I Romerska riket associerades grönt med gudinnan Venus och var en populär färg som användes i målningar, mosaik och glas.
Grönt användes mer sällan till kläder under medeltiden, då metoderna för att tillverka grönt gav färg av dålig kvalitet, som lätt tappade färgen och dåligt tålde tvättning. Associationen till grönt var ambivalent, då Djävulen vanligen avbildades antingen som röd, svart eller grön. Samtidigt sågs grönt som en färg mellan svart och vit, som kunde överbygga skillnader och lugna spänningar.
I medeltida litteratur var den "svarta riddaren" ofta en mystisk hjälte i förklädnad, den vita riddaren hans visa rådgivare och mentor, den röda riddaren hjältens motståndare, ofta Djävulens riddare, medan den gröna riddaren var en omogen riddare som ännu inte uppnått sin styrka.
I medeltidens färglära associerades grönt även med rikedom och bars gärna av personer som var rika utan att tillhöra adeln, det vill säga köpmän och borgare.
Under 1400-talet var grönt tillsammans med svart den främsta modefärgen, och bars då av personer som demonstrerade sin rikedom genom att kunna bära gröna kläder, som inte höll färgen länge.
Under 1500-talet uppfanns en ny metod att framgångsrikt färga kläder permanent gröna, och färgen blev därefter vanligare för kläder, men det var fortfarande en dyr färg eftersom tekniken för att åstadkomma grönt var komplicerad.
Under 1700-talet associerades grönt med naturen och de då romantiska idéerna kring naturen, och hyllades av Goethe som en avslappnande färg. Det var en omtyckt färg under rokokon, men inte lika vanlig som rokokons tre huvudfärger rosa, ljusblått och vitt.
Under romantikens era på 1800-talet blev grönt en populär modefärg, associerad med naturen och kärleken.
Associationer och symbolisk innebörd
Den dominerande färgen hos levande växtlighet är grön, och färgen grön är förknippad med en mängd associationer, föreställningar och symboliska betydelser. Men även om denna symbolik utgår från allmänmänskliga upplevelser så kan färgens innebörd tolkas mycket olika i olika kulturer, och även i olika sammanhang inom en och samma kultur. Den enskilda personens associationer är dessutom alltid personliga.
När det gäller färgers fysiologiska och psykologiska påverkan på människor finns det stora kunskapsluckor och mycket litet är vetenskapligt belagt. Trots detta presenteras omstridda resultat ofta som fakta, och både bland allmänheten och professionella färgsättare florerar mängd myter och faktoider som forskare inom området inte kan bekräfta. En rad studier pekar på att gröna färger har en lugnande effekt, men samtidigt visas att kulörtheten - hur stark färgen är - ofta är viktigare än kulörtonen.
De symboliska betydelserna hos färgen grön har ofta samband med natur, växande, fruktbarhet och liv. En helt annorlunda association ges i ordet "giftgrön" som hänvisar till det arsenikhaltiga pigmentet schweinfurtergrönt.
I den västerländska kulturkretsen används grönt som symbol för hopp (medan tro symboliseras av blått och kärlek av rött),.
När det gäller standardiserade färgsymboler används grönt ofta för att visa på det som är tillåtet, säkert och tryggt. Några exempel är den gröna trafiksignalen och markering av skydds- och första hjälpen-utrustning och nödutgångar.
Som politisk färg används grönt för partier med miljö och/eller jordbruksprofil. Exempelvis har det svenska Centerpartiet och Centern i Finland, liksom Miljöpartiet de gröna i Sverige och Gröna förbundet i Finland grönt som sin partifärg. Även utanför partipolitiken representerar grönt grupper som arbetar med miljöfrågor, till exempel Greenpeace.
Både protestantisk och katolsk liturgi använder grönt i kyrkans textilier när ingen annan färg är föreskriven.
Islam sammanknippas ofta med grönt, även om det finns olika teorier om ursprunget till detta.
Grönt sammanknippas ofta med Irland, och speciellt med Irlands skyddshelgon S:t Patrick. Hur detta samband har uppkommit är oklart, och en möjlig förklaring är att S:t Patrick sägs ha använt en treklöver - shamrock - för att förklara den heliga treenigheten.
Inom bilsport har den gröna färgen british racing green använts som nationalfärg för Storbritannien, se internationella bilsportfärger.
Användning
För grönfärgning av mat används främst ämnena klorofyll (E140 och E141) och kinolin (E104) och, i länder där det är lagligt, "Grön S" (E142).
Eftersom grön är en bra kamouflagefärg där det finns växtlighet, används den ofta som uniformsfärg av militären.
I bildförstärkare används grönt ljus för att det är vid denna våglängd (555 nm) som det mänskliga ögat har sin bästa förmåga att urskilja nyanser (i dagsljus, fotopiskt seende).
Grönt i specialuttryck
Gröna vågen syftar på en rörelse där människor flyttar från staden till landsbygden.
Grönt ljus används inte bara för trafiksignaler utan också i överförd bemärkelse för att något är tillåtet eller sanktionerat.
Giftgrön syftar ursprungligen på de hälsovådliga effekterna av koppararsenikpigmentet Schweinfurtergrönt.
Greenwashing ("gröntvättning") syftar på åtgärder som får miljöskadlig verksamhet att framstå som bra för miljön.
Grönt är slanguttryck för marijuana.
Se även
Färgord
Färg
Limegrön
Olivgrön
Smaragdgrön
British racing green
Källor
Färgord | swedish | 0.417095 |
evolutionary_advantage_of_red-green_color_blindness/Color_blindness.txt |
Color blindness or color vision deficiency (CVD) is the decreased ability to see color or differences in color. The severity of color blindness ranges from mostly unnoticeable to full absence of color perception. Color blindness is usually an inherited problem or variation in the functionality of one or more of the three classes of cone cells in the retina, which mediate color vision. The most common form is caused by a genetic condition called congenital red–green color blindness (including protan and deutan types), which affects up to 1 in 12 males (8%) and 1 in 200 females (0.5%). The condition is more prevalent in males, because the opsin genes responsible are located on the X chromosome. Rarer genetic conditions causing color blindness include congenital blue–yellow color blindness (tritan type), blue cone monochromacy, and achromatopsia. Color blindness can also result from physical or chemical damage to the eye, the optic nerve, parts of the brain, or from medication toxicity. Color vision also naturally degrades in old age.
Diagnosis of color blindness is usually done with a color vision test, such as the Ishihara test. There is no cure for most causes of color blindness, however there is ongoing research into gene therapy for some severe conditions causing color blindness. Minor forms of color blindness do not significantly affect daily life and the color blind automatically develop adaptations and coping mechanisms to compensate for the deficiency. However, diagnosis may allow an individual, or their parents/teachers to actively accommodate the condition. Color blind glasses (e.g. EnChroma) may help the red–green color blind at some color tasks, but they do not grant the wearer "normal color vision" or the ability to see "new" colors. Some mobile apps can use a device's camera to identify colors.
Depending on the jurisdiction, the color blind are ineligible for certain careers, such as aircraft pilots, train drivers, police officers, firefighters, and members of the armed forces. The effect of color blindness on artistic ability is controversial, but a number of famous artists are believed to have been color blind.
A color blind person will have decreased (or no) color discrimination along the red–green axis, blue–yellow axis, or both. However, the vast majority of the color blind are only affected on their red–green axis.
The first indication of color blindness generally consists of a person using the wrong color for an object, such as when painting, or calling a color by the wrong name. The colors that are confused are very consistent among people with the same type of color blindness.
Confusion colors are pairs or groups of colors that will often be mistaken by the color blind. Confusion colors for red–green color blindness include:
Confusion colors for tritan include:
These colors of confusion are defined quantitatively by straight confusion lines plotted in CIEXYZ, usually plotted on the corresponding chromaticity diagram. The lines all intersect at a copunctal point, which varies with the type of color blindness. Chromaticities along a confusion line will appear metameric to dichromats of that type. Anomalous trichromats of that type will see the chromaticities as metameric if they are close enough, depending on the strength of their CVD. For two colors on a confusion line to be metameric, the chromaticities first have to be made isoluminant, meaning equal in lightness. Also, colors that may be isoluminant to the standard observer may not be isoluminant to a person with dichromacy.
Cole describes four color tasks, all of which are impeded to some degree by color blindness:
The following sections describe specific color tasks with which the color blind typically have difficulty.
Color blindness causes difficulty with the connotative color tasks associated with selecting or preparing food. Selecting food for ripeness can be difficult; the green–yellow transition of bananas is particularly hard to identify. It can also be difficult to detect bruises, mold, or rot on some foods, to determine when meat is done by color, to distinguish some varietals, such as a Braeburn vs. a Granny Smith apple, or to distinguish colors associated with artificial flavors (e.g. jelly beans, sports drinks).
Changes in skin color due to bruising, sunburn, rashes or even blushing are easily missed by the red–green color blind.
The colors of traffic lights can be difficult for the red–green color blindness. This difficulty includes distinguishing red/amber lights from sodium street lamps, distinguishing green lights (closer to cyan) from normal white lights, and distinguishing red from amber lights, especially when there are no positional clues available (see image).
The main coping mechanism to overcome these challenges is to memorize the position of lights. The order of the common triplet traffic light is standardized as red–amber–green from top to bottom or left to right. Cases that deviate from this standard are rare. One such case is a traffic light in Tipperary Hill in Syracuse, New York, which is upside-down (green–amber–red top to bottom) due to the sentiments of its Irish American community. However, the light has been criticized due to the potential hazard it poses for color blind drivers.
There are other several features of traffic lights available that help accommodate the color blind. British Rail signals use more easily identifiable colors: The red is blood red, the amber is yellow and the green is a bluish color. Most British road traffic lights are mounted vertically on a black rectangle with a white border (forming a "sighting board"), so that drivers can more easily look for the position of the light. In the eastern provinces of Canada, traffic lights are sometimes differentiated by shape in addition to color: square for red, diamond for yellow, and circle for green (see image).
Navigation lights in marine and aviation settings employ red and green lights to signal the relative position of other ships or aircraft. Railway signal lights also rely heavily on red–green–yellow colors. In both cases, these color combinations can be difficult for the red–green color blind. Lantern Tests are a common means of simulating these light sources to determine not necessarily whether someone is color blind, but whether they can functionally distinguish these specific signal colors. Those who cannot pass this test are generally completely restricted from working on aircraft, ships or rail, for example.
Color analysis is the analysis of color in its use in fashion, to determine personal color combinations that are most aesthetically pleasing. Colors to combine can include clothing, accessories, makeup, hair color, skin color, eye color, etc. Color analysis involves many aesthetic and comparative color task that can be difficult for the color blind.
Inability to distinguish color does not necessarily preclude the ability to become a celebrated artist. The 20th century expressionist painter Clifton Pugh, three-time winner of Australia's Archibald Prize, on biographical, gene inheritance and other grounds has been identified as a person with protanopia. 19th century French artist Charles Méryon became successful by concentrating on etching rather than painting after he was diagnosed as having a red–green deficiency. Jin Kim's red–green color blindness did not stop him from becoming first an animator and later a character designer with Walt Disney Animation Studios.
Deuteranomals are better at distinguishing shades of khaki, which may be advantageous when looking for predators, food, or camouflaged objects hidden among foliage. Dichromats tend to learn to use texture and shape clues and so may be able to penetrate camouflage that has been designed to deceive individuals with normal color vision.
Some tentative evidence finds that the color blind are better at penetrating certain color camouflages. Such findings may give an evolutionary reason for the high rate of red–green color blindness. There is also a study suggesting that people with some types of color blindness can distinguish colors that people with normal color vision are not able to distinguish. In World War II, color blind observers were used to penetrate camouflage.
In the presence of chromatic noise, the color blind are more capable of seeing a luminous signal, as long as the chromatic noise appears metameric to them. This is the effect behind most "reverse" Pseudoisochromatic plates (e.g. "hidden digit" Ishihara plates) that are discernible to the color blind but unreadable to people with typical color vision.
Color codes are useful tools for designers to convey information. The interpretation of this information requires users to perform a variety of Color Tasks, usually comparative but also sometimes connotative or denotative. However, these tasks are often problematic for the color blind when design of the color code has not followed best practices for accessibility. For example, one of the most ubiquitous connotative color codes is the "red means bad and green means good" or similar systems, based on the classic signal light colors. However, this color coding will almost always be undifferentiable to deutans or protans, and therefore should be avoided or supplemented with a parallel connotative system (symbols, smileys, etc.).
Good practices to ensure design is accessible to the color blind include:
A common task for designers is to select a subset of colors (qualitative colormap) that are as mutually differentiable as possible (salient). For example, player pieces in a board game should be as different as possible.
Classic advice suggests using Brewer palettes, but several of these are not actually accessible to the color blind.
Unfortunately, the colors with the greatest contrast to the red–green color blind tend to be colors of confusion to the blue–yellow color blind, and vice versa. However, since red–green is much more prevalent than blue–yellow CVD, design should generally prioritize those users (deutans then protans).
A common task for data visualization is to represent a color scale, or sequential colormap, often in the form of a heat map or choropleth. Several scales are designed with special consideration for the color blind and are widespread in academia, including Cividis, Viridis and Parula. These comprise a light-to-dark scale superimposed on a yellow-to-blue scale, making them monotonic and perceptually uniform to all forms of color vision.
Much terminology has existed and does exist for the classification of color blindness, but the typical classification for color blindness follows the von Kries classifications, which uses severity and affected cone for naming.
Based on clinical appearance, color blindness may be described as total or partial. Total color blindness (monochromacy) is much less common than partial color blindness. Partial color blindness includes dichromacy and anomalous trichromacy, but is often clinically defined as mild, moderate or strong.
Monochromacy is often called total color blindness since there is no ability to see color. Although the term may refer to acquired disorders such as cerebral achromatopsia, it typically refers to congenital color vision disorders, namely rod monochromacy and blue cone monochromacy).
In cerebral achromatopsia, a person cannot perceive colors even though the eyes are capable of distinguishing them. Some sources do not consider these to be true color blindness, because the failure is of perception, not of vision. They are forms of visual agnosia.
Monochromacy is the condition of possessing only a single channel for conveying information about color. Monochromats are unable to distinguish any colors and perceive only variations in brightness. Congenital monochromacy occurs in two primary forms:
Dichromats can match any color they see with some mixture of just two primary colors (in contrast to those with normal sight (trichromats) who can distinguish three primary colors). Dichromats usually know they have a color vision problem, and it can affect their daily lives. Dichromacy in humans includes protanopia, deuteranopia, and tritanopia. Out of the male population, 2% have severe difficulties distinguishing between red, orange, yellow, and green (orange and yellow are different combinations of red and green light). Colors in this range, which appear very different to a normal viewer, appear to a dichromat to be the same or a similar color. The terms protanopia, deuteranopia, and tritanopia come from Greek, and respectively mean "inability to see (anopia) with the first (prot-), second (deuter-), or third (trit-) [cone]".
Anomalous trichromacy is the mildest type of color deficiency, but the severity ranges from almost dichromacy (strong) to almost normal trichromacy (mild). In fact, many mild anomalous trichromats have very little difficulty carrying out tasks that require normal color vision and some may not even be aware that they have a color vision deficiency. The types of anomalous trichromacy include protanomaly, deuteranomaly and tritanomaly. It is approximately three times more common than dichromacy. Anomalous trichromats exhibit trichromacy, but the color matches they make differ from normal trichromats. In order to match a given spectral yellow light, protanomalous observers need more red light in a red/green mixture than a normal observer, and deuteranomalous observers need more green. This difference can be measured by an instrument called an Anomaloscope, where red and green lights are mixed by a subject to match a yellow light.
There are two major types of color blindness: difficulty distinguishing between red and green, and difficulty distinguishing between blue and yellow. These definitions are based on the phenotype of the partial color blindness. Clinically, it is more common to use a genotypical definition, which describes which cone/opsin is affected.
Red–green color blindness includes protan and deutan CVD. Protan CVD is related to the L-cone and includes protanomaly (anomalous trichromacy) and protanopia (dichromacy). Deutan CVD is related to the M-cone and includes deuteranomaly (anomalous trichromacy) and deuteranopia (dichromacy). The phenotype (visual experience) of deutans and protans is quite similar. Common colors of confusion include red/brown/green/yellow as well as blue/purple. Both forms are almost always symptomatic of congenital red–green color blindness, so affects males disproportionately more than females. This form of color blindness is sometimes referred to as daltonism after John Dalton, who had red–green dichromacy. In some languages, daltonism is still used to describe red–green color blindness.
Blue–yellow color blindness includes tritan CVD. Tritan CVD is related to the S-cone and includes tritanomaly (anomalous trichromacy) and tritanopia (dichromacy). Blue–yellow color blindness is much less common than red–green color blindness, and more often has acquired causes than genetic. Tritans have difficulty discerning between bluish and greenish hues. Tritans have a neutral point at 571 nm (yellowish).
The below table shows the cone complements for different types of human color vision, including those considered color blindness, normal color vision and 'superior' color vision. The cone complement contains the types of cones (or their opsins) expressed by an individual.
Color blindness is any deviation of color vision from normal trichromatic color vision (often as defined by the standard observer) that produces a reduced gamut. Mechanisms for color blindness are related to the functionality of cone cells, and often to the expression of photopsins, the photopigments that 'catch' photons and thereby convert light into chemical signals.
Color vision deficiencies can be classified as inherited or acquired.
Color blindness is typically an inherited genetic disorder. The most common forms of color blindness are associated with the Photopsin genes, but the mapping of the human genome has shown there are many causative mutations that do not directly affect the opsins. Mutations capable of causing color blindness originate from at least 19 different chromosomes and 56 different genes (as shown online at the Online Mendelian Inheritance in Man [OMIM]).
By far the most common form of color blindness is congenital red–green color blindness (Daltonism), which includes protanopia/protanomaly and deuteranopia/deuteranomaly. These conditions are mediated by the OPN1LW and OPN1MW genes, respectively, both on the X chromosome. An 'affected' gene is either missing (as in Protanopia and Deuteranopia - Dichromacy) or is a chimeric gene (as in Protanomaly and Deuteranomaly).
Since the OPN1LW and OPN1MW genes are on the X chromosome, they are sex-linked, and therefore affect males and females disproportionately. Because the color blind 'affected' alleles are recessive, color blindness specifically follows X-linked recessive inheritance. Males have only one X chromosome (XY), and females have two (XX); Because the male only has one of each gene, if it is affected, the male will be color blind. Because a female has two alleles of each gene (one on each chromosome), if only one gene is affected, the dominant normal alleles will "override" the affected, recessive allele and the female will have normal color vision. However, if the female has two mutated alleles, she will still be color blind. This is why there is a disproportionate prevalence of color blindness, with ~8% of males exhibiting color blindness and ~0.5% of females.
Congenital blue–yellow color blindness is a much rarer form of color blindness including tritanopia/tritanomaly. These conditions are mediated by the OPN1SW gene on Chromosome 7 which encodes the S-opsin protein and follows autosomal dominant inheritance. The cause of blue–yellow color blindness is not analogous to the cause of red–green color blindness, i.e. the peak sensitivity of the S-opsin does not shift to longer wavelengths. Rather, there are 6 known point mutations of OPN1SW that degrade the performance of the S-cones. The OPN1SW gene is almost invariant in the human population. Congenital tritan defects are often progressive, with nearly normal trichromatic vision in childhood (e.g. mild tritanomaly) progressing to dichromacy (tritanopia) as the S-cones slowly die. Tritanomaly and tritanopia are therefore different penetrance of the same disease, and some sources have argued that tritanomaly therefore be referred to as incomplete tritanopia.
Several inherited diseases are known to cause color blindness, including achromatopsia, cone dystrophy, Leber's congenital amaurosis and retinitis pigmentosa. These can be congenital or commence in childhood or adulthood. They can be static/stationary or progressive. Progressive diseases often involve deterioration of the retina and other parts of the eye, so often progress from color blindness to more severe visual impairments, up to and including total blindness.
Physical trauma can cause color blindness, either neurologically – brain trauma which produces swelling of the brain in the occipital lobe – or retinally, either acute (e.g. from laser exposure) or chronic (e.g. from ultraviolet light exposure).
Color blindness may also present itself as a symptom of degenerative diseases of the eye, such as cataract and age-related macular degeneration, and as part of the retinal damage caused by diabetes. Vitamin A deficiency may also cause color blindness.
Color blindness may be a side effect of prescription drug use. For example, red–green color blindness can be caused by ethambutol, a drug used in the treatment of tuberculosis. Blue–yellow color blindness can be caused by sildenafil, an active component of Viagra. Hydroxychloroquine can also lead to hydroxychloroquine retinopathy, which includes various color defects. Exposure to chemicals such as styrene or organic solvents can also lead to color vision defects.
Simple colored filters can also create mild color vision deficiencies. John Dalton's original hypothesis for his deuteranopia was actually that the vitreous humor of his eye was discolored:
An autopsy of his eye after his death in 1844 showed this to be definitively untrue, though other filters are possible. Actual physiological examples usually affect the blue–yellow opponent channel and are named Cyanopsia and Xanthopsia, and are most typically an effect of yellowing or removal of the lens.
The opponent channels can also be affected by the prevalence of certain cones in the retinal mosaic. The cones are not equally prevalent and not evenly distributed in the retina. When the number of one of these cone types is significantly reduced, this can also lead to or contribute to a color vision deficiency. This is one of the causes of tritanomaly.
Some people are also unable to distinct between blue and green, which appears to be a combination of culture and exposure to UV-light.
The main method for diagnosing a color vision deficiency is in testing the color vision directly. The Ishihara color test is the test most often used to detect red–green deficiencies and most often recognized by the public. Some tests are clinical in nature, designed to be fast, simple, and effective at identifying broad categories of color blindness. Others focus on precision and are generally available only in academic settings.
While genetic testing cannot directly evaluate a subject's color vision (phenotype), most congenital color vision deficiencies are well-correlated with genotype. Therefore, the genotype can be directly evaluated and used to predict the phenotype. This is especially useful for progressive forms that do not have a strongly color deficient phenotype at a young age. However, it can also be used to sequence the L- and M-Opsins on the X-chromosome, since the most common alleles of these two genes are known and have even been related to exact spectral sensitivities and peak wavelengths. A subject's color vision can therefore be classified through genetic testing, but this is just a prediction of the phenotype, since color vision can be affected by countless non-genetic factors such as your cone mosaic.
Despite much recent improvement in gene therapy for color blindness, there is currently no FDA approved treatment for any form of CVD, and otherwise no cure for CVD currently exists. Management of the condition by using lenses to alleviate symptoms or smartphone apps to aid with daily tasks is possible.
There are three kinds of lenses that an individual can wear that can increase their accuracy in some color related tasks (although none of these will "fix" color blindness or grant the wearer normal color vision):
Many mobile and computer applications have been developed to aid color blind individuals in completing color tasks:
In 2003, a cybernetic device called eyeborg was developed to allow the wearer to hear sounds representing different colors. Achromatopsic artist Neil Harbisson was the first to use such a device in early 2004; the eyeborg allowed him to start painting in color by memorizing the sound corresponding to each color. In 2012, at a TED Conference, Harbisson explained how he could now perceive colors outside the ability of human vision.
Color blindness affects a large number of individuals, with protans and deutans being the most common types. In individuals with Northern European ancestry, as many as 8 percent of men and 0.4 percent of women experience congenital color deficiency. Interestingly, even Dalton's very first paper already arrived upon this 8% number:
During the 17th and 18th century, several philosophers hypothesized that not all individuals perceived colors in the same way:
The phenomenon only came to be scientifically studied in 1794, when English chemist John Dalton gave the first account of color blindness in a paper to the Manchester Literary and Philosophical Society, which was published in 1798 as Extraordinary Facts relating to the Vision of Colours: With Observations. Genetic analysis of Dalton's preserved eyeball confirmed him as having deuteranopia in 1995, some 150 years after his death.
Influenced by Dalton, German writer J. W. von Goethe studied color vision abnormalities in 1798 by asking two young subjects to match pairs of colors.
In 1875, the Lagerlunda train crash in Sweden brought color blindness to the forefront. Following the crash, Professor Alarik Frithiof Holmgren, a physiologist, investigated and concluded that the color blindness of the engineer (who had died) had caused the crash. Professor Holmgren then created the first test for color vision using multicolored skeins of wool to detect color blindness and thereby exclude the color blind from jobs in the transportation industry requiring color vision to interpret safety signals. However, there is a claim that there is no firm evidence that color deficiency did cause the collision, or that it might have not been the sole cause.
In 1920, Frederick William Edridge-Green devised an alternative theory of color vision and color blindness based on Newton's classification of 7 fundamental colors (ROYGBIV). Edridge-Green classified color vision based on how many distinct colors a subject could see in the spectrum. Normal subjects were termed hexachromic as they could not discern Indigo. Subjects with superior color vision, who could discern indigo, were heptachromic. The color blind were therefore dichromic (equivalent to dichromacy) or tri-, tetra- or pentachromic (anomalous trichromacy).
In the United States, under federal anti-discrimination laws such as the Americans with Disabilities Act, color vision deficiencies have not been found to constitute a disability that triggers protection from workplace discrimination.
A Brazilian court ruled that the color blind are protected by the Inter-American Convention on the Elimination of All Forms of Discrimination against Person with Disabilities. At trial, it was decided that the carriers of color blindness have a right of access to wider knowledge, or the full enjoyment of their human condition.
Color blindness may make it difficult or impossible for a person to engage in certain activities. Persons with color blindness may be legally or practically barred from occupations in which color perception is an essential part of the job (e.g., mixing paint colors), or in which color perception is important for safety (e.g., operating vehicles in response to color-coded signals). This occupational safety principle originates from the aftermath of the 1875 Lagerlunda train crash, which Alarik Frithiof Holmgren blamed on the color blindness of the engineer and created the first occupational screening test (Holmgren's wool test) against the color blind.
Color vision is important for occupations using telephone or computer networking cabling, as the individual wires inside the cables are color-coded using green, orange, brown, blue and white colors. Electronic wiring, transformers, resistors, and capacitors are color-coded as well, using black, brown, red, orange, yellow, green, blue, violet, gray, white, silver, and gold.
Participation, officiating and viewing sporting events can be impacted by color blindness. Professional football players Thomas Delaney and Fabio Carvalho have discussed the difficulties when color clashes occur, and research undertaken by FIFA has shown that enjoyment and player progression can be hampered by issues distinguishing the difference between the pitch and training objects or field markings. Snooker World Champions Mark Williams and Peter Ebdon sometimes need to ask the referee for help distinguishing between the red and brown balls due to their color blindness. Both have played foul shots on notable occasions by potting the wrong ball.
Red–green color blindness can make it difficult to drive, primarily due to the inability to differentiate red–amber–green traffic lights. Protans are further disadvantaged due to the darkened perception of reds, which can make it more difficult to quickly recognize brake lights. In response, some countries have refused to grant driver's licenses to individuals with color blindness:
Although many aspects of aviation depend on color coding, only a few of them are critical enough to be interfered with by some milder types of color blindness. Some examples include color-gun signaling of aircraft that have lost radio communication, color-coded glide-path indications on runways, and the like. Some jurisdictions restrict the issuance of pilot credentials to persons with color blindness for this reason. Restrictions may be partial, allowing color-blind persons to obtain certification but with restrictions, or total, in which case color-blind persons are not permitted to obtain piloting credentials at all.
In the United States, the Federal Aviation Administration requires that pilots be tested for normal color vision as part of their medical clearance in order to obtain the required medical certificate, a prerequisite to obtaining a pilot's certification. If testing reveals color blindness, the applicant may be issued a license with restrictions, such as no night flying and no flying by color signals—such a restriction effectively prevents a pilot from holding certain flying occupations, such as that of an airline pilot, although commercial pilot certification is still possible, and there are a few flying occupations that do not require night flight and thus are still available to those with restrictions due to color blindness (e.g., agricultural aviation). The government allows several types of tests, including medical standard tests (e.g., the Ishihara, Dvorine, and others) and specialized tests oriented specifically to the needs of aviation. If an applicant fails the standard tests, they will receive a restriction on their medical certificate that states: "Not valid for night flying or by color signal control". They may apply to the FAA to take a specialized test, administered by the FAA. Typically, this test is the "color vision light gun test". For this test an FAA inspector will meet the pilot at an airport with an operating control tower. The color signal light gun will be shone at the pilot from the tower, and they must identify the color. If they pass they may be issued a waiver, which states that the color vision test is no longer required during medical examinations. They will then receive a new medical certificate with the restriction removed. This was once a Statement of Demonstrated Ability (SODA), but the SODA was dropped, and converted to a simple waiver (letter) early in the 2000s.
Research published in 2009 carried out by the City University of London's Applied Vision Research Centre, sponsored by the UK's Civil Aviation Authority and the U.S. Federal Aviation Administration, has established a more accurate assessment of color deficiencies in pilot applicants' red/green and yellow–blue color range which could lead to a 35% reduction in the number of prospective pilots who fail to meet the minimum medical threshold.
Effects[edit]
A color blind person will have decreased (or no) color discrimination along the red–green axis, blue–yellow axis, or both. However, the vast majority of the color blind are only affected on their red–green axis.
The first indication of color blindness generally consists of a person using the wrong color for an object, such as when painting, or calling a color by the wrong name. The colors that are confused are very consistent among people with the same type of color blindness.
Normal sight
Deuteranopic sight
Protanopic sight
Tritanopic sight
Monochromatic sight
Confusion colors[edit]
Confusion lines for the three types of dichromacy superimposed on CIEXYZ color space.
Confusion colors are pairs or groups of colors that will often be mistaken by the color blind. Confusion colors for red–green color blindness include:
cyan and grey
rose-pink and grey
blue and purple
yellow and neon green
red, green, orange, brown
Confusion colors for tritan include:
yellow and grey
blue and green
dark blue/violet and black
violet and yellow-green
red and rose-pink
These colors of confusion are defined quantitatively by straight confusion lines plotted in CIEXYZ, usually plotted on the corresponding chromaticity diagram. The lines all intersect at a copunctal point, which varies with the type of color blindness. Chromaticities along a confusion line will appear metameric to dichromats of that type. Anomalous trichromats of that type will see the chromaticities as metameric if they are close enough, depending on the strength of their CVD. For two colors on a confusion line to be metameric, the chromaticities first have to be made isoluminant, meaning equal in lightness. Also, colors that may be isoluminant to the standard observer may not be isoluminant to a person with dichromacy.
Color tasks[edit]
Main article: Color task
Cole describes four color tasks, all of which are impeded to some degree by color blindness:
Comparative – When multiple colors must be compared, such as with mixing paint
Connotative – When colors are given an implicit meaning, such as red = stop
Denotative – When identifying colors, for example by name, such as "where is the yellow ball?"
Aesthetic – When colors look nice – or convey an emotional response – but do not carry explicit meaning
The following sections describe specific color tasks with which the color blind typically have difficulty.
Food[edit]
Simulation of the normal (above) and dichromatic (below) perception of red and green apples
Color blindness causes difficulty with the connotative color tasks associated with selecting or preparing food. Selecting food for ripeness can be difficult; the green–yellow transition of bananas is particularly hard to identify. It can also be difficult to detect bruises, mold, or rot on some foods, to determine when meat is done by color, to distinguish some varietals, such as a Braeburn vs. a Granny Smith apple, or to distinguish colors associated with artificial flavors (e.g. jelly beans, sports drinks).
Skin color[edit]
Main article: Evolution of color vision in primates § Skin Tone
Changes in skin color due to bruising, sunburn, rashes or even blushing are easily missed by the red–green color blind.
Traffic lights[edit]
See also: § Driving
The lack of standard positional clues makes this light difficult to interpret.
The colors of traffic lights can be difficult for the red–green color blindness. This difficulty includes distinguishing red/amber lights from sodium street lamps, distinguishing green lights (closer to cyan) from normal white lights, and distinguishing red from amber lights, especially when there are no positional clues available (see image).
The infamous inverted traffic light in Syracuse, NY
The main coping mechanism to overcome these challenges is to memorize the position of lights. The order of the common triplet traffic light is standardized as red–amber–green from top to bottom or left to right. Cases that deviate from this standard are rare. One such case is a traffic light in Tipperary Hill in Syracuse, New York, which is upside-down (green–amber–red top to bottom) due to the sentiments of its Irish American community. However, the light has been criticized due to the potential hazard it poses for color blind drivers.
Horizontal traffic light in Halifax, Nova Scotia, Canada
There are other several features of traffic lights available that help accommodate the color blind. British Rail signals use more easily identifiable colors: The red is blood red, the amber is yellow and the green is a bluish color. Most British road traffic lights are mounted vertically on a black rectangle with a white border (forming a "sighting board"), so that drivers can more easily look for the position of the light. In the eastern provinces of Canada, traffic lights are sometimes differentiated by shape in addition to color: square for red, diamond for yellow, and circle for green (see image).
Signal lights[edit]
See also: § Occupations
Navigation lights in marine and aviation settings employ red and green lights to signal the relative position of other ships or aircraft. Railway signal lights also rely heavily on red–green–yellow colors. In both cases, these color combinations can be difficult for the red–green color blind. Lantern Tests are a common means of simulating these light sources to determine not necessarily whether someone is color blind, but whether they can functionally distinguish these specific signal colors. Those who cannot pass this test are generally completely restricted from working on aircraft, ships or rail, for example.
Fashion[edit]
See also: Color of clothing
Color analysis is the analysis of color in its use in fashion, to determine personal color combinations that are most aesthetically pleasing. Colors to combine can include clothing, accessories, makeup, hair color, skin color, eye color, etc. Color analysis involves many aesthetic and comparative color task that can be difficult for the color blind.
Art[edit]
Inability to distinguish color does not necessarily preclude the ability to become a celebrated artist. The 20th century expressionist painter Clifton Pugh, three-time winner of Australia's Archibald Prize, on biographical, gene inheritance and other grounds has been identified as a person with protanopia. 19th century French artist Charles Méryon became successful by concentrating on etching rather than painting after he was diagnosed as having a red–green deficiency. Jin Kim's red–green color blindness did not stop him from becoming first an animator and later a character designer with Walt Disney Animation Studios.
Advantages[edit]
Deuteranomals are better at distinguishing shades of khaki, which may be advantageous when looking for predators, food, or camouflaged objects hidden among foliage. Dichromats tend to learn to use texture and shape clues and so may be able to penetrate camouflage that has been designed to deceive individuals with normal color vision.
Some tentative evidence finds that the color blind are better at penetrating certain color camouflages. Such findings may give an evolutionary reason for the high rate of red–green color blindness. There is also a study suggesting that people with some types of color blindness can distinguish colors that people with normal color vision are not able to distinguish. In World War II, color blind observers were used to penetrate camouflage.
In the presence of chromatic noise, the color blind are more capable of seeing a luminous signal, as long as the chromatic noise appears metameric to them. This is the effect behind most "reverse" Pseudoisochromatic plates (e.g. "hidden digit" Ishihara plates) that are discernible to the color blind but unreadable to people with typical color vision.
Digital design[edit]
See also: Color coding in data visualization
Testing the colors of a web chart, (center), to ensure that no information is lost to the various forms of color blindness.
Color codes are useful tools for designers to convey information. The interpretation of this information requires users to perform a variety of Color Tasks, usually comparative but also sometimes connotative or denotative. However, these tasks are often problematic for the color blind when design of the color code has not followed best practices for accessibility. For example, one of the most ubiquitous connotative color codes is the "red means bad and green means good" or similar systems, based on the classic signal light colors. However, this color coding will almost always be undifferentiable to deutans or protans, and therefore should be avoided or supplemented with a parallel connotative system (symbols, smileys, etc.).
Good practices to ensure design is accessible to the color blind include:
When possible (e.g. in simple video games or apps), allowing the user to choose their own colors is the most inclusive design practice.
Using other signals that are parallel to the color coding, such as patterns, shapes, size or order. This not only helps the color blind, but also aids understanding by normally sighted people by providing them with multiple reinforcing cues.
Using brightness contrast (different shades) in addition to color contrast (different hues)
To achieve good contrast, conventional wisdom suggests converting a (digital) design to grayscale to ensure there is sufficient brightness contrast between colors. However, this does not account for the different perceptions of brightness to different varieties of color blindness, especially protan CVD, tritan CVD and monochromacy.
Viewing the design through a CVD Simulator to ensure the information carried by color is still sufficiently conveyed. At a minimum, the design should be tested for deutan CVD, the most common kind of color blindness.
Maximizing the area of colors (e.g. increase size, thickness or boldness of colored element) makes the color easier to identify. Color contrast improves as the angle the color subtends on the retina increases. This applies to all types of color vision.
Maximizing brightness (value) and saturation (chroma) of the colors to maximize color contrast.
Converting connotative tasks to comparative tasks by including a legend, even when the meaning is considered obvious (e.g. red means danger).
Avoiding denotative color tasks (color naming) when possible. Some denotative tasks can be converted to comparative tasks by depicting the actual color whenever the color name is mentioned; for example, colored typography in "purple", purple or "purple ( )".
For denotative tasks (color naming), using the most common shades of colors. For example, green and yellow are colors of confusion in red–green CVD, but it is very common to mix forest green ( ) with bright yellow ( ). Mistakes by the color blind increase drastically when uncommon shades are used, e.g. neon green ( ) with dark yellow ( ).
For denotative tasks, using colors that are classically associated with a color name. For example, use "firetruck" red ( ) instead of burgundy ( ) to represent the word "red".
Unordered Information[edit]
Colors of board game pieces must be carefully chosen to be accessible to the color blind
A common task for designers is to select a subset of colors (qualitative colormap) that are as mutually differentiable as possible (salient). For example, player pieces in a board game should be as different as possible.
Classic advice suggests using Brewer palettes, but several of these are not actually accessible to the color blind.
Unfortunately, the colors with the greatest contrast to the red–green color blind tend to be colors of confusion to the blue–yellow color blind, and vice versa. However, since red–green is much more prevalent than blue–yellow CVD, design should generally prioritize those users (deutans then protans).
Ordered Information[edit]
Three sequential colormaps that have been designed to be accessible to the color blind.
A common task for data visualization is to represent a color scale, or sequential colormap, often in the form of a heat map or choropleth. Several scales are designed with special consideration for the color blind and are widespread in academia, including Cividis, Viridis and Parula. These comprise a light-to-dark scale superimposed on a yellow-to-blue scale, making them monotonic and perceptually uniform to all forms of color vision.
Classification[edit]
These color charts show how different color blind people see compared to a person with normal color vision.
Much terminology has existed and does exist for the classification of color blindness, but the typical classification for color blindness follows the von Kries classifications, which uses severity and affected cone for naming.
Based on severity[edit]
Based on clinical appearance, color blindness may be described as total or partial. Total color blindness (monochromacy) is much less common than partial color blindness. Partial color blindness includes dichromacy and anomalous trichromacy, but is often clinically defined as mild, moderate or strong.
Monochromacy[edit]
Main article: Monochromacy
Monochromacy is often called total color blindness since there is no ability to see color. Although the term may refer to acquired disorders such as cerebral achromatopsia, it typically refers to congenital color vision disorders, namely rod monochromacy and blue cone monochromacy).
In cerebral achromatopsia, a person cannot perceive colors even though the eyes are capable of distinguishing them. Some sources do not consider these to be true color blindness, because the failure is of perception, not of vision. They are forms of visual agnosia.
Monochromacy is the condition of possessing only a single channel for conveying information about color. Monochromats are unable to distinguish any colors and perceive only variations in brightness. Congenital monochromacy occurs in two primary forms:
Rod monochromacy, frequently called complete achromatopsia, where the retina contains no cone cells, so that in addition to the absence of color discrimination, vision in lights of normal intensity is difficult.
Cone monochromacy is the condition of having only a single class of cone. A cone monochromat can have good pattern vision at normal daylight levels, but will not be able to distinguish hues. Cone monochromacy is divided into classes defined by the single remaining cone class. However, red and green cone monochromats have not been definitively described in the literature. Blue cone monochromacy is caused by lack of functionality of L (red) and M (green) cones, and is therefore mediated by the same genes as red–green color blindness (on the X chromosome). Peak spectral sensitivities are in the blue region of the visible spectrum (near 440 nm). People with this condition generally show nystagmus ("jiggling eyes"), photophobia (light sensitivity), reduced visual acuity, and myopia (nearsightedness). Visual acuity usually falls to the 20/50 to 20/400 range.
Dichromacy[edit]
Main article: Dichromacy
Dichromats can match any color they see with some mixture of just two primary colors (in contrast to those with normal sight (trichromats) who can distinguish three primary colors). Dichromats usually know they have a color vision problem, and it can affect their daily lives. Dichromacy in humans includes protanopia, deuteranopia, and tritanopia. Out of the male population, 2% have severe difficulties distinguishing between red, orange, yellow, and green (orange and yellow are different combinations of red and green light). Colors in this range, which appear very different to a normal viewer, appear to a dichromat to be the same or a similar color. The terms protanopia, deuteranopia, and tritanopia come from Greek, and respectively mean "inability to see (anopia) with the first (prot-), second (deuter-), or third (trit-) [cone]".
Anomalous trichromacy[edit]
Anomalous trichromacy is the mildest type of color deficiency, but the severity ranges from almost dichromacy (strong) to almost normal trichromacy (mild). In fact, many mild anomalous trichromats have very little difficulty carrying out tasks that require normal color vision and some may not even be aware that they have a color vision deficiency. The types of anomalous trichromacy include protanomaly, deuteranomaly and tritanomaly. It is approximately three times more common than dichromacy. Anomalous trichromats exhibit trichromacy, but the color matches they make differ from normal trichromats. In order to match a given spectral yellow light, protanomalous observers need more red light in a red/green mixture than a normal observer, and deuteranomalous observers need more green. This difference can be measured by an instrument called an Anomaloscope, where red and green lights are mixed by a subject to match a yellow light.
Based on affected cone[edit]
There are two major types of color blindness: difficulty distinguishing between red and green, and difficulty distinguishing between blue and yellow. These definitions are based on the phenotype of the partial color blindness. Clinically, it is more common to use a genotypical definition, which describes which cone/opsin is affected.
Red–green color blindness[edit]
Red–green color blindness includes protan and deutan CVD. Protan CVD is related to the L-cone and includes protanomaly (anomalous trichromacy) and protanopia (dichromacy). Deutan CVD is related to the M-cone and includes deuteranomaly (anomalous trichromacy) and deuteranopia (dichromacy). The phenotype (visual experience) of deutans and protans is quite similar. Common colors of confusion include red/brown/green/yellow as well as blue/purple. Both forms are almost always symptomatic of congenital red–green color blindness, so affects males disproportionately more than females. This form of color blindness is sometimes referred to as daltonism after John Dalton, who had red–green dichromacy. In some languages, daltonism is still used to describe red–green color blindness.
Illustration of the distribution of cone cells in the fovea of an individual with normal color vision (left), and a color blind (protanopic) retina. The center of the fovea holds very few blue-sensitive cones.
Protan (2% of males): Lacking, or possessing anomalous L-opsins for long-wavelength sensitive cone cells. Protans have a neutral point at a cyan-like wavelength around 492 nm (see spectral color for comparison)—that is, they cannot discriminate light of this wavelength from white. For a protanope, the brightness of red, is much reduced compared to normal. This dimming can be so pronounced that reds may be confused with black or dark gray, and red traffic lights may appear to be extinguished. They may learn to distinguish reds from yellows primarily on the basis of their apparent brightness or lightness, not on any perceptible hue difference. Violet, lavender, and purple are indistinguishable from various shades of blue. A very few people have been found who have one normal eye and one protanopic eye. These unilateral dichromats report that with only their protanopic eye open, they see wavelengths shorter than neutral point as blue and those longer than it as yellow.
Deutan (6% of males): Lacking, or possessing anomalous M-opsins for medium-wavelength sensitive cone cells. Their neutral point is at a slightly longer wavelength, 498 nm, a more greenish hue of cyan. Deutans have the same hue discrimination problems as protans, but without the dimming of long wavelengths. Deuteranopic unilateral dichromats report that with only their deuteranopic eye open, they see wavelengths shorter than neutral point as blue and longer than it as yellow.
Blue–yellow color blindness[edit]
Blue–yellow color blindness includes tritan CVD. Tritan CVD is related to the S-cone and includes tritanomaly (anomalous trichromacy) and tritanopia (dichromacy). Blue–yellow color blindness is much less common than red–green color blindness, and more often has acquired causes than genetic. Tritans have difficulty discerning between bluish and greenish hues. Tritans have a neutral point at 571 nm (yellowish).
Tritan (< 0.01% of individuals): Lacking, or possessing anomalous S-opsins or short-wavelength sensitive cone cells. Tritans see short-wavelength colors (blue, indigo and spectral violet) as greenish and drastically dimmed, some of these colors even as black. Yellow and orange are indistinguishable from white and pink respectively, and purple colors are perceived as various shades of red. Unlike protans and deutans, the mutation for this color blindness is carried on chromosome 7. Therefore, it is not sex-linked (equally prevalent in both males and females). The OMIM gene code for this mutation is 304000 "Colorblindness, Partial Tritanomaly".
Tetartan is the "fourth type" of color blindness, and a type of blue–yellow color blindness. However, its existence is hypothetical and given the molecular basis of human color vision, it is unlikely this type could exist.
Summary of cone complements[edit]
The below table shows the cone complements for different types of human color vision, including those considered color blindness, normal color vision and 'superior' color vision. The cone complement contains the types of cones (or their opsins) expressed by an individual.
Cone system
Red
Green
Blue
N = normalA = anomalous
N
A
N
A
N
A
1
Normal vision
Trichromacy
Normal
2
Protanomaly
Anomalous trichromacy
Partialcolorblindness
Red–green
3
Protanopia
Dichromacy
4
Deuteranomaly
Anomalous trichromacy
5
Deuteranopia
Dichromacy
6
Tritanomaly
Anomalous trichromacy
Blue–yellow
7
Tritanopia
Dichromacy
8
Blue cone monochromacy
Monochromacy
Total color blindness
9
Achromatopsia
10
Tetrachromacy(carrier theory)
Tetrachromacy
'Superior'
11
Causes[edit]
See also: Trichromatic color vision and Congenital red–green color blindness § Mechanism
Color blindness is any deviation of color vision from normal trichromatic color vision (often as defined by the standard observer) that produces a reduced gamut. Mechanisms for color blindness are related to the functionality of cone cells, and often to the expression of photopsins, the photopigments that 'catch' photons and thereby convert light into chemical signals.
Color vision deficiencies can be classified as inherited or acquired.
Inherited: inherited or congenital/genetic color vision deficiencies are most commonly caused by mutations of the genes encoding opsin proteins. However, several other genes can also lead to less common and/or more severe forms of color blindness.
Acquired: color blindness that is not present at birth, may be caused by chronic illness, accidents, medication, chemical exposure or simply normal aging processes.
Genetics[edit]
This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (May 2023) (Learn how and when to remove this template message)
Color blindness is typically an inherited genetic disorder. The most common forms of color blindness are associated with the Photopsin genes, but the mapping of the human genome has shown there are many causative mutations that do not directly affect the opsins. Mutations capable of causing color blindness originate from at least 19 different chromosomes and 56 different genes (as shown online at the Online Mendelian Inheritance in Man [OMIM]).
Genetics of red–green color blindness[edit]
Main article: Congenital red–green color blindness § Genetics
Punnett squares for each combination of parents' color vision status giving probabilities of their offsprings' status; A superscript 'c' denotes a chromosome with an affected gene
By far the most common form of color blindness is congenital red–green color blindness (Daltonism), which includes protanopia/protanomaly and deuteranopia/deuteranomaly. These conditions are mediated by the OPN1LW and OPN1MW genes, respectively, both on the X chromosome. An 'affected' gene is either missing (as in Protanopia and Deuteranopia - Dichromacy) or is a chimeric gene (as in Protanomaly and Deuteranomaly).
Since the OPN1LW and OPN1MW genes are on the X chromosome, they are sex-linked, and therefore affect males and females disproportionately. Because the color blind 'affected' alleles are recessive, color blindness specifically follows X-linked recessive inheritance. Males have only one X chromosome (XY), and females have two (XX); Because the male only has one of each gene, if it is affected, the male will be color blind. Because a female has two alleles of each gene (one on each chromosome), if only one gene is affected, the dominant normal alleles will "override" the affected, recessive allele and the female will have normal color vision. However, if the female has two mutated alleles, she will still be color blind. This is why there is a disproportionate prevalence of color blindness, with ~8% of males exhibiting color blindness and ~0.5% of females.
Genetics of blue–yellow color blindness[edit]
Congenital blue–yellow color blindness is a much rarer form of color blindness including tritanopia/tritanomaly. These conditions are mediated by the OPN1SW gene on Chromosome 7 which encodes the S-opsin protein and follows autosomal dominant inheritance. The cause of blue–yellow color blindness is not analogous to the cause of red–green color blindness, i.e. the peak sensitivity of the S-opsin does not shift to longer wavelengths. Rather, there are 6 known point mutations of OPN1SW that degrade the performance of the S-cones. The OPN1SW gene is almost invariant in the human population. Congenital tritan defects are often progressive, with nearly normal trichromatic vision in childhood (e.g. mild tritanomaly) progressing to dichromacy (tritanopia) as the S-cones slowly die. Tritanomaly and tritanopia are therefore different penetrance of the same disease, and some sources have argued that tritanomaly therefore be referred to as incomplete tritanopia.
Other genetic causes[edit]
Several inherited diseases are known to cause color blindness, including achromatopsia, cone dystrophy, Leber's congenital amaurosis and retinitis pigmentosa. These can be congenital or commence in childhood or adulthood. They can be static/stationary or progressive. Progressive diseases often involve deterioration of the retina and other parts of the eye, so often progress from color blindness to more severe visual impairments, up to and including total blindness.
Non-genetic causes[edit]
Physical trauma can cause color blindness, either neurologically – brain trauma which produces swelling of the brain in the occipital lobe – or retinally, either acute (e.g. from laser exposure) or chronic (e.g. from ultraviolet light exposure).
Color blindness may also present itself as a symptom of degenerative diseases of the eye, such as cataract and age-related macular degeneration, and as part of the retinal damage caused by diabetes. Vitamin A deficiency may also cause color blindness.
Color blindness may be a side effect of prescription drug use. For example, red–green color blindness can be caused by ethambutol, a drug used in the treatment of tuberculosis. Blue–yellow color blindness can be caused by sildenafil, an active component of Viagra. Hydroxychloroquine can also lead to hydroxychloroquine retinopathy, which includes various color defects. Exposure to chemicals such as styrene or organic solvents can also lead to color vision defects.
Simple colored filters can also create mild color vision deficiencies. John Dalton's original hypothesis for his deuteranopia was actually that the vitreous humor of his eye was discolored:
I was led to conjecture that one of the humours of my eye must be a transparent, but coloured, medium, so constituted as to absorb red and green rays principally... I suppose it must be the vitreous humor.— John Dalton, Extraordinary facts relating to the vision of colours: with observations (1798)
An autopsy of his eye after his death in 1844 showed this to be definitively untrue, though other filters are possible. Actual physiological examples usually affect the blue–yellow opponent channel and are named Cyanopsia and Xanthopsia, and are most typically an effect of yellowing or removal of the lens.
The opponent channels can also be affected by the prevalence of certain cones in the retinal mosaic. The cones are not equally prevalent and not evenly distributed in the retina. When the number of one of these cone types is significantly reduced, this can also lead to or contribute to a color vision deficiency. This is one of the causes of tritanomaly.
Some people are also unable to distinct between blue and green, which appears to be a combination of culture and exposure to UV-light.
Diagnosis[edit]
Color vision test[edit]
Main article: Color vision test
An Ishihara test image as seen by subjects with normal color vision and by those with a variety of color deficiencies
The main method for diagnosing a color vision deficiency is in testing the color vision directly. The Ishihara color test is the test most often used to detect red–green deficiencies and most often recognized by the public. Some tests are clinical in nature, designed to be fast, simple, and effective at identifying broad categories of color blindness. Others focus on precision and are generally available only in academic settings.
Pseudoisochromatic plates, a classification which includes the Ishihara color test and HRR test, embed a figure in the plate as a number of spots surrounded by spots of a slightly different color. These colors must appear identical (metameric) to the color blind but distinguishable to color normals. Pseudoisochromatic plates are used as screening tools because they are cheap, fast, and simple, but they do not provide precise diagnosis of CVD.
Lanterns, such as the Farnsworth Lantern Test, project small colored lights to a subject, who is required to identify the color of the lights. The colors are those of typical signal lights, i.e. red, green, and yellow, which also happen to be colors of confusion of red–green CVD. Lanterns do not diagnose color blindness, but they are occupational screening tests to ensure an applicant has sufficient color discrimination to be able to perform a job.
A Farnsworth D-15 test
Arrangement tests can be used as screening or diagnostic tools. The Farnsworth–Munsell 100 hue test is very sensitive, but the Farnsworth D-15 is a simplified version used specifically for screening for CVD. In either case, the subject is asked to arrange a set of colored caps or chips to form a gradual transition of color between two anchor caps.
Anomaloscopes are typically designed to detect red–green deficiencies and are based on the Rayleigh match, which compares a mixture of red and green light in variable proportions to a fixed spectral yellow of variable luminosity. The subject must change the two variables until the colors appear to match. They are expensive and require expertise to administer, so they are generally only used in academic settings.
Genetic testing[edit]
While genetic testing cannot directly evaluate a subject's color vision (phenotype), most congenital color vision deficiencies are well-correlated with genotype. Therefore, the genotype can be directly evaluated and used to predict the phenotype. This is especially useful for progressive forms that do not have a strongly color deficient phenotype at a young age. However, it can also be used to sequence the L- and M-Opsins on the X-chromosome, since the most common alleles of these two genes are known and have even been related to exact spectral sensitivities and peak wavelengths. A subject's color vision can therefore be classified through genetic testing, but this is just a prediction of the phenotype, since color vision can be affected by countless non-genetic factors such as your cone mosaic.
Management[edit]
Despite much recent improvement in gene therapy for color blindness, there is currently no FDA approved treatment for any form of CVD, and otherwise no cure for CVD currently exists. Management of the condition by using lenses to alleviate symptoms or smartphone apps to aid with daily tasks is possible.
Lenses[edit]
Main article: Color blind glasses
There are three kinds of lenses that an individual can wear that can increase their accuracy in some color related tasks (although none of these will "fix" color blindness or grant the wearer normal color vision):
A red-tint contact lens worn over the non-dominant eye will leverage binocular disparity to improve discrimination of some colors. However, it can make other colors more difficult to distinguish. A 1981 review of various studies to evaluate the effect of the X-chrom (one brand) contact lens concluded that, while the lens may allow the wearer to achieve a better score on certain color vision tests, it did not correct color vision in the natural environment. A case history using the X-Chrom lens for a rod monochromat is reported and an X-Chrom manual is online.
Tinted glasses (e.g. Pilestone/Colorlite glasses) apply a tint (e.g. magenta) to incoming light that can distort colors in a way that makes some color tasks easier to complete. These glasses can circumvent many color vision tests, though this is typically not allowed.
Glasses with a notch filter (e.g. EnChroma glasses) filter a narrow band of light that excites both the L and M cones (yellow–green wavelengths). When combined with an additional stopband in the short wavelength (blue) region, these lenses may constitute a neutral-density filter (have no color tint). They improve on the other lens types by causing less distortion of colors and will essentially increase the saturation of some colors. They will only work on trichromats (anomalous or normal), and unlike the other types, do not have a significant effect on Dichromats. The glasses do not significantly increase one's ability on color blind tests.
Aids[edit]
Many mobile and computer applications have been developed to aid color blind individuals in completing color tasks:
Some applications (e.g. color pickers) can identify the name (or coordinates within a color space) of a color on screen or the color of an object by using the device's camera.
Some applications will make images easier to interpret by the color blind by enhancing color contrast in natural images and/or information graphics. These methods are generally called daltonization algorithms.
Some applications can simulate color blindness by applying a filter to an image or screen that reduces the gamut of an image to that of a specific type of color blindness. While they do not directly help color blind people, they allow those with normal color vision to understand how the color blind see the world. Their use can help improve inclusive design by allowing designers to simulate their own images to ensure they are accessible to the color blind.
In 2003, a cybernetic device called eyeborg was developed to allow the wearer to hear sounds representing different colors. Achromatopsic artist Neil Harbisson was the first to use such a device in early 2004; the eyeborg allowed him to start painting in color by memorizing the sound corresponding to each color. In 2012, at a TED Conference, Harbisson explained how he could now perceive colors outside the ability of human vision.
Epidemiology[edit]
Rates of color blindness
Males
Females
Dichromacy
2.4%
0.03%
Protanopia
1.3%
0.02%
Deuteranopia
1.2%
0.01%
Tritanopia
0.008%
0.008%
Anomalous trichromacy
6.3%
0.37%
Protanomaly
1.3%
0.02%
Deuteranomaly
5.0%
0.35%
Tritanomaly
0.0001%
0.0001%
Color blindness affects a large number of individuals, with protans and deutans being the most common types. In individuals with Northern European ancestry, as many as 8 percent of men and 0.4 percent of women experience congenital color deficiency. Interestingly, even Dalton's very first paper already arrived upon this 8% number:
...it is remarkable that, out of 25 pupils I once had, to whom I explained this subject, 2 were found to agree with me...— John Dalton, Extraordinary facts relating to the vision of colours: with observations (1798)
History[edit]
An 1895 illustration of normal vision and various kinds of color blindness.
During the 17th and 18th century, several philosophers hypothesized that not all individuals perceived colors in the same way:
...there is no reason to suppose a perfect resemblance in the disposition of the Optic Nerve in all Men, since there is an infinite variety in every thing in Nature, and chiefly in those that are Material, 'tis therefore very probable that all Men see not the same Colours in the same Objects.— Nicolas Malebranche, The search after truth (1674)
In the power of conceiving colors, too, there are striking differences among individuals: and, indeed, I am inclined to suspect, that, in the greater number of instances, the supposed defects of sight in this respect ought to be ascribed rather to a defect in the power of conception.— Dugald Stewart, Elements of the philosophy of the human mind (1792)
The phenomenon only came to be scientifically studied in 1794, when English chemist John Dalton gave the first account of color blindness in a paper to the Manchester Literary and Philosophical Society, which was published in 1798 as Extraordinary Facts relating to the Vision of Colours: With Observations. Genetic analysis of Dalton's preserved eyeball confirmed him as having deuteranopia in 1995, some 150 years after his death.
Influenced by Dalton, German writer J. W. von Goethe studied color vision abnormalities in 1798 by asking two young subjects to match pairs of colors.
In 1875, the Lagerlunda train crash in Sweden brought color blindness to the forefront. Following the crash, Professor Alarik Frithiof Holmgren, a physiologist, investigated and concluded that the color blindness of the engineer (who had died) had caused the crash. Professor Holmgren then created the first test for color vision using multicolored skeins of wool to detect color blindness and thereby exclude the color blind from jobs in the transportation industry requiring color vision to interpret safety signals. However, there is a claim that there is no firm evidence that color deficiency did cause the collision, or that it might have not been the sole cause.
In 1920, Frederick William Edridge-Green devised an alternative theory of color vision and color blindness based on Newton's classification of 7 fundamental colors (ROYGBIV). Edridge-Green classified color vision based on how many distinct colors a subject could see in the spectrum. Normal subjects were termed hexachromic as they could not discern Indigo. Subjects with superior color vision, who could discern indigo, were heptachromic. The color blind were therefore dichromic (equivalent to dichromacy) or tri-, tetra- or pentachromic (anomalous trichromacy).
Rights[edit]
In the United States, under federal anti-discrimination laws such as the Americans with Disabilities Act, color vision deficiencies have not been found to constitute a disability that triggers protection from workplace discrimination.
A Brazilian court ruled that the color blind are protected by the Inter-American Convention on the Elimination of All Forms of Discrimination against Person with Disabilities. At trial, it was decided that the carriers of color blindness have a right of access to wider knowledge, or the full enjoyment of their human condition.
Occupations[edit]
Color blindness may make it difficult or impossible for a person to engage in certain activities. Persons with color blindness may be legally or practically barred from occupations in which color perception is an essential part of the job (e.g., mixing paint colors), or in which color perception is important for safety (e.g., operating vehicles in response to color-coded signals). This occupational safety principle originates from the aftermath of the 1875 Lagerlunda train crash, which Alarik Frithiof Holmgren blamed on the color blindness of the engineer and created the first occupational screening test (Holmgren's wool test) against the color blind.
...I consider that to [Holmgren] above all others do we owe the present and future control of color-blindness on land and sea, by which life and property are safer, and the risks of travelling less.— Benjamin Joy Jeffries, Color-blindness: Its Danger & Its Detection (1879)
Color vision is important for occupations using telephone or computer networking cabling, as the individual wires inside the cables are color-coded using green, orange, brown, blue and white colors. Electronic wiring, transformers, resistors, and capacitors are color-coded as well, using black, brown, red, orange, yellow, green, blue, violet, gray, white, silver, and gold.
Participation, officiating and viewing sporting events can be impacted by color blindness. Professional football players Thomas Delaney and Fabio Carvalho have discussed the difficulties when color clashes occur, and research undertaken by FIFA has shown that enjoyment and player progression can be hampered by issues distinguishing the difference between the pitch and training objects or field markings. Snooker World Champions Mark Williams and Peter Ebdon sometimes need to ask the referee for help distinguishing between the red and brown balls due to their color blindness. Both have played foul shots on notable occasions by potting the wrong ball.
Driving[edit]
See also: § Traffic lights
Red–green color blindness can make it difficult to drive, primarily due to the inability to differentiate red–amber–green traffic lights. Protans are further disadvantaged due to the darkened perception of reds, which can make it more difficult to quickly recognize brake lights. In response, some countries have refused to grant driver's licenses to individuals with color blindness:
In April 2003, Romania removed color blindness from its list of disqualifying conditions for learner driver's licenses. It is now qualified as a condition that could potentially compromise driver safety, therefore a driver may have to be evaluated by an authorized ophthalmologist to determine if they can drive safely. As of May 2008, there is an ongoing campaign to remove the legal restrictions that prohibit color blind citizens from getting driver's licenses.
In June 2020, India relaxed its ban on driver's licenses for the color blind to now only apply to those with strong CVD. While previously restricted, those who test as mild or moderate can now pass the medical requirements.
Australia instituted a tiered ban on the color blind from obtaining commercial driver's licenses in 1994. This included a ban for all protans, and a stipulation that deutans must pass the Farnsworth Lantern. The stipulation on deutans was revoked in 1997 citing a lack of available test facilities, and the ban on protans was revoked in 2003.
All color blind individuals are banned from obtaining a driver's license in China and since 2016 in Russia (2012 for dichromats).
Piloting aircraft[edit]
See also: § Signal lights
Although many aspects of aviation depend on color coding, only a few of them are critical enough to be interfered with by some milder types of color blindness. Some examples include color-gun signaling of aircraft that have lost radio communication, color-coded glide-path indications on runways, and the like. Some jurisdictions restrict the issuance of pilot credentials to persons with color blindness for this reason. Restrictions may be partial, allowing color-blind persons to obtain certification but with restrictions, or total, in which case color-blind persons are not permitted to obtain piloting credentials at all.
In the United States, the Federal Aviation Administration requires that pilots be tested for normal color vision as part of their medical clearance in order to obtain the required medical certificate, a prerequisite to obtaining a pilot's certification. If testing reveals color blindness, the applicant may be issued a license with restrictions, such as no night flying and no flying by color signals—such a restriction effectively prevents a pilot from holding certain flying occupations, such as that of an airline pilot, although commercial pilot certification is still possible, and there are a few flying occupations that do not require night flight and thus are still available to those with restrictions due to color blindness (e.g., agricultural aviation). The government allows several types of tests, including medical standard tests (e.g., the Ishihara, Dvorine, and others) and specialized tests oriented specifically to the needs of aviation. If an applicant fails the standard tests, they will receive a restriction on their medical certificate that states: "Not valid for night flying or by color signal control". They may apply to the FAA to take a specialized test, administered by the FAA. Typically, this test is the "color vision light gun test". For this test an FAA inspector will meet the pilot at an airport with an operating control tower. The color signal light gun will be shone at the pilot from the tower, and they must identify the color. If they pass they may be issued a waiver, which states that the color vision test is no longer required during medical examinations. They will then receive a new medical certificate with the restriction removed. This was once a Statement of Demonstrated Ability (SODA), but the SODA was dropped, and converted to a simple waiver (letter) early in the 2000s.
Research published in 2009 carried out by the City University of London's Applied Vision Research Centre, sponsored by the UK's Civil Aviation Authority and the U.S. Federal Aviation Administration, has established a more accurate assessment of color deficiencies in pilot applicants' red/green and yellow–blue color range which could lead to a 35% reduction in the number of prospective pilots who fail to meet the minimum medical threshold.
See also[edit]
Medicine portal
Color agnosia – Ability to see colors, but inability to recognize colors.
Color anomia – Ability to see colors, but inability to name colors.
List of people with color blindness
Motion blindness
Tetrachromacy | biology | 225903 | https://da.wikipedia.org/wiki/Kontrast%20%28lys%29 | Kontrast (lys) | Kontraster kan enten beskrives som forskelle i belysningsstyrke mellem tilgrænsende områder (luminanskontrast), for eksempel sorte bogstaver på hvid bund, eller som forskelle i farve (farvekontrast).
Lys | danish | 0.8048 |
evolutionary_advantage_of_red-green_color_blindness/Red.txt |
Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondary color (made from magenta and yellow) in the CMYK color model, and is the complementary color of cyan. Reds range from the brilliant yellow-tinged scarlet and vermillion to bluish-red crimson, and vary in shade from the pale red pink to the dark red burgundy.
Red pigment made from ochre was one of the first colors used in prehistoric art. The Ancient Egyptians and Mayans colored their faces red in ceremonies; Roman generals had their bodies colored red to celebrate victories. It was also an important color in China, where it was used to color early pottery and later the gates and walls of palaces. In the Renaissance, the brilliant red costumes for the nobility and wealthy were dyed with kermes and cochineal. The 19th century brought the introduction of the first synthetic red dyes, which replaced the traditional dyes. Red became a symbolic color of communism and socialism; Soviet Russia adopted a red flag following the Bolshevik Revolution in 1917. The Soviet red banner would subsequently be used throughout the entire history of the Soviet Union, starting from 1922 and ending with its 1991 dissolution. China adopted its own red flag following the Chinese Revolution of 1949. A red flag was also adopted by North Vietnam in 1954, and by all of Vietnam in 1975.
Since red is the color of blood, it has historically been associated with sacrifice, danger, and courage. Modern surveys in Europe and the United States show red is also the color most commonly associated with heat, activity, passion, sexuality, anger, love, and joy. In China, India, and many other Asian countries it is the color symbolizing happiness and good fortune.
Shades and variations
Main article: Shades of red
Varieties of the color red may differ in hue, chroma (also called saturation, intensity, or colorfulness), or lightness (or value, tone, or brightness), or in two or three of these qualities. Variations in value are also called tints and shades, a tint being a red or other hue mixed with white, a shade being mixed with black. Four examples are shown below.
The cardinal takes its name from the color worn by Catholic cardinals.Pink is a pale shade of red. Cherry blossoms in the Tsutsujigaoka Park, Sendai, Miyagi, Japan.Vermilion is similar to scarlet, but slightly more orange. This is sindoor, a red cosmetic powder used in India; some Hindu women put a stripe of sindoor in their hair to show they are married.Ruby is the color of a cut and polished ruby gemstone.
In science and nature
Seeing red
Bulls, like dogs and many other animals, have dichromacy, which means they cannot distinguish the color red. They charge the matador's cape because of its motion, not its color.
The human eye sees red when it looks at light with a wavelength between approximately 625 and 740 nanometers. It is a primary color in the RGB color model and the light just past this range is called infrared, or below red, and cannot be seen by human eyes, although it can be sensed as heat. In the language of optics, red is the color evoked by light that stimulates neither the S or the M (short and medium wavelength) cone cells of the retina, combined with a fading stimulation of the L (long-wavelength) cone cells.
Primates can distinguish the full range of the colors of the spectrum visible to humans, but many kinds of mammals, such as dogs and cattle, have dichromacy, which means they can see blues and yellows, but cannot distinguish red and green (both are seen as gray). Bulls, for instance, cannot see the red color of the cape of a bullfighter, but they are agitated by its movement. (See color vision).
One theory for why primates developed sensitivity to red is that it allowed ripe fruit to be distinguished from unripe fruit and inedible vegetation. This may have driven further adaptations by species taking advantage of this new ability, such as the emergence of red faces.
Red light is used to help adapt night vision in low-light or night time, as the rod cells in the human eye are not sensitive to red.
In color theory and on a computer screen
In the RYB color model, which is the basis of traditional color theory, red is one of the three primary colors, along with blue and yellow. Painters in the Renaissance mixed red and blue to make violet: Cennino Cennini, in his 15th-century manual on painting, wrote, "If you want to make a lovely violet colour, take fine lac (red lake), ultramarine blue (the same amount of the one as of the other) with a binder"; he noted that it could also be made by mixing blue indigo and red hematite.
In the CMY and CMYK color models, red is a secondary color subtractively mixed from magenta and yellow.
In the RGB color model, red, green and blue are additive primary colors. Red, green and blue light combined makes white light, and these three colors, combined in different mixtures, can produce nearly any other color. This principle is used to generate colors on such as computer monitors and televisions. For example, magenta on a computer screen is made by a similar formula to that used by Cennino Cennini in the Renaissance to make violet, but using additive colors and light instead of pigment: it is created by combining red and blue light at equal intensity on a black screen. Violet is made on a computer screen in a similar way, but with a greater amount of blue light and less red light.
In a traditional color wheel from 1708, red, yellow and blue are primary colors. Red and yellow make orange; red and blue make violet.
In modern color theory, red, green and blue are the additive primary colors, and together they make white. A combination of red, green and blue light in varying proportions makes all the colors on your computer screen and television screen.
Tiny Red, green and blue sub-pixels (enlarged on left side of image) create the colors you see on your computer screen and TV.
Color of sunset
Main article: Sunset § Colors
Sunsets and sunrises are often red because of an optical effect called Rayleigh scattering.
As a ray of white sunlight travels through the atmosphere to the eye, some of the colors are scattered out of the beam by air molecules and airborne particles due to Rayleigh scattering, changing the final color of the beam that is seen. Colors with a shorter wavelength, such as blue and green, scatter more strongly, and are removed from the light that finally reaches the eye. At sunrise and sunset, when the path of the sunlight through the atmosphere to the eye is longest, the blue and green components are removed almost completely, leaving the longer wavelength orange and red light. The remaining reddened sunlight can also be scattered by cloud droplets and other relatively large particles, which give the sky above the horizon its red glow.
Lasers
Lasers emitting in the red region of the spectrum have been available since the invention of the ruby laser in 1960. In 1962 the red helium–neon laser was invented, and these two types of lasers were widely used in many scientific applications including holography, and in education. Red helium–neon lasers were used commercially in LaserDisc players. The use of red laser diodes became widespread with the commercial success of modern DVD players, which use a 660 nm laser diode technology. Today, red and red-orange laser diodes are widely available to the public in the form of extremely inexpensive laser pointers. Portable, high-powered versions are also available for various applications. More recently, 671 nm diode-pumped solid state (DPSS) lasers have been introduced to the market for all-DPSS laser display systems, particle image velocimetry, Raman spectroscopy, and holography.
Red's wavelength has been an important factor in laser technologies; red lasers, used in early compact disc technologies, are being replaced by blue lasers, as red's longer wavelength causes the laser's recordings to take up more space on the disc than would blue-laser recordings.
Astronomy
Mars is called the Red Planet because of the reddish color imparted to its surface by the abundant iron oxide present there.
Astronomical objects that are moving away from the observer exhibit a Doppler red shift.
Jupiter's surface displays a Great Red Spot caused by an oval-shaped mega storm south of the planet's equator.
Red giants are stars that have exhausted the supply of hydrogen in their cores and switched to thermonuclear fusion of hydrogen in a shell that surrounds its core. They have radii tens to hundreds of times larger than that of the Sun. However, their outer envelope is much lower in temperature, giving them an orange hue. Despite the lower energy density of their envelope, red giants are many times more luminous than the Sun due to their large size.
Red supergiants like Betelgeuse, Antares, Mu Cephei, VV Cephei, and VY Canis Majoris one of the biggest stars in the Universe, are the biggest variety of red giants. They are huge in size, with radii 200 to 1700 times greater than the Sun, but relatively cool in temperature (3000–4500 K), causing their distinct red tint. Because they are shrinking rapidly in size, they are surrounded by an envelope or skin much bigger than the star itself. The envelope of Betelgeuse is 250 times bigger than the star inside.
A red dwarf is a small and relatively cool star, which has a mass of less than half that of the Sun and a surface temperature of less than 4,000 K. Red dwarfs are by far the most common type of star in the Galaxy, but due to their low luminosity, from Earth, none are visible to the naked eye.
Interstellar reddening is caused by the extinction of radiation by dust and gas
Mars appears to be red because of iron oxide on its surface.
Mira, a red giant
Artist's impression of a red dwarf, a small, relatively cool star that appears red due to its temperature
Pigments and dyes
See also: Red pigments
Red ochre cliffs near Roussillon in France. Red ochre is composed of clay tinted with hematite. Ochre was the first pigment used by man in prehistoric cave paintings.
Vermilion pigment, made from cinnabar. This was the pigment used in the murals of Pompeii and to color Chinese lacquerware beginning in the Song dynasty.
Red lead, also known as minium, has been used since the time of the ancient Greeks. Chemically it is known as lead tetroxide. The Romans prepared it by the roasting of lead white pigment. It was commonly used in the Middle Ages for the headings and decoration of illuminated manuscripts.
The roots of the Rubia tinctorum, or madder plant, produced the most common red dye used from ancient times until the 19th century.
Alizarin was the first synthetic red dye, created by German chemists in 1868. It duplicated the colorant in the madder plant, but was cheaper and longer lasting. After its introduction, the production of natural dyes from the madder plant virtually ceased.
Food coloring
The most common synthetic food coloring today is Allura Red AC, a red azo dye that goes by several names including: Allura Red, Food Red 17, C.I. 16035, FD&C Red 40, It was originally manufactured from coal tar, but now is mostly made from petroleum.
In Europe, Allura Red AC is not recommended for consumption by children. It is banned in Denmark, Belgium, France and Switzerland, and was also banned in Sweden until the country joined the European Union in 1994. The European Union approves Allura Red AC as a food colorant, but EU countries' local laws banning food colorants are preserved.
In the United States, Allura Red AC is approved by the Food and Drug Administration (FDA) for use in cosmetics, drugs, and food. It is used in some tattoo inks and is used in many products, such as soft drinks, children's medications, and cotton candy. On June 30, 2010, the Center for Science in the Public Interest (CSPI) called for the FDA to ban Red 40.
Because of public concerns about possible health risks associated with synthetic dyes, many companies have switched to using natural pigments such as carmine, made from crushing the tiny female cochineal insect. This insect, originating in Mexico and Central America, was used to make the brilliant scarlet dyes of the European Renaissance.
Autumn leaves
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed.Find sources: "Red" – news · newspapers · books · scholar · JSTOR (July 2021) (Learn how and when to remove this template message)
The red of autumn leaves is produced by pigments called anthocyanins. They are not present in the leaf throughout the growing season, but are actively produced towards the end of summer. They develop in late summer in the sap of the cells of the leaf, and this development is the result of complex interactions of many influences—both inside and outside the plant. Their formation depends on the breakdown of sugars in the presence of bright light as the level of phosphate in the leaf is reduced.
During the summer growing season, phosphate is at a high level. It has a vital role in the breakdown of the sugars manufactured by chlorophyll. But in the fall, phosphate, along with the other chemicals and nutrients, moves out of the leaf into the stem of the plant. When this happens, the sugar-breakdown process changes, leading to the production of anthocyanin pigments. The brighter the light during this period, the greater the production of anthocyanins and the more brilliant the resulting color display. When the days of autumn are bright and cool, and the nights are chilly but not freezing, the brightest colorations usually develop.
Anthocyanins temporarily color the edges of some of the very young leaves as they unfold from the buds in early spring. They also give the familiar color to such common fruits as cranberries, red apples, blueberries, cherries, raspberries, and plums.
Anthocyanins are present in about 10% of tree species in temperate regions, although in certain areas—a famous example being New England—up to 70% of tree species may produce the pigment. In autumn forests they appear vivid in the maples, oaks, sourwood, sweetgums, dogwoods, tupelos, cherry trees and persimmons. These same pigments often combine with the carotenoids' colors to create the deeper orange, fiery reds, and bronzes typical of many hardwood species. (See Autumn leaf color).
Blood and other reds in nature
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed.Find sources: "Red" – news · newspapers · books · scholar · JSTOR (July 2021) (Learn how and when to remove this template message)
Oxygenated blood is red due to the presence of oxygenated hemoglobin that contains iron molecules, with the iron components reflecting red light. Red meat gets its color from the iron found in the myoglobin and hemoglobin in the muscles and residual blood.
Plants like apples, strawberries, cherries, tomatoes, peppers, and pomegranates are often colored by forms of carotenoids, red pigments that also assist photosynthesis.
Red blood cell agar. Blood appears red due to the iron molecules in blood cells.
A red setter or Irish setter
A pair of European red foxes
The European robin or robin redbreast
Hair color
Main article: Red hair
Red hair only occurs in 1–2% of the human population.
Red hair occurs naturally on approximately 1–2% of the human population. It occurs more frequently (2–6%) in people of northern or western European ancestry, and less frequently in other populations. Red hair appears in people with two copies of a recessive gene on chromosome 16 which causes a mutation in the MC1R protein.
Red hair varies from a deep burgundy through burnt orange to bright copper. It is characterized by high levels of the reddish pigment pheomelanin (which also accounts for the red color of the lips) and relatively low levels of the dark pigment eumelanin. The term "redhead" (originally redd hede) has been in use since at least 1510.
In animal and human behavior
Red is associated with dominance in a number of animal species. For example, in mandrills, red coloration of the face is greatest in alpha males, increasingly less prominent in lower ranking subordinates, and directly correlated with levels of testosterone. Red can also affect the perception of dominance by others, leading to significant differences in mortality, reproductive success and parental investment between individuals displaying red and those not. In humans, wearing red has been linked with increased performance in competitions, including professional sport and multiplayer video games. Controlled tests have demonstrated that wearing red does not increase performance or levels of testosterone during exercise, so the effect is likely to be produced by perceived rather than actual performance. Judges of tae kwon do have been shown to favor competitors wearing red protective gear over blue, and, when asked, a significant majority of people say that red abstract shapes are more "dominant", "aggressive", and "likely to win a physical competition" than blue shapes. In contrast to its positive effect in physical competition and dominance behavior, exposure to red decreases performance in cognitive tasks and elicits aversion in psychological tests where subjects are placed in an "achievement" context (e.g. taking an IQ test).
History and art
See also: History of red
In prehistory and the ancient world
Bison in red ochre in the Cave of Altamira, Spain, from upper Paleolithic era (36,000 BC)
Image of a human hand created with red ochre in Pech Merle cave, France (Gravettian era, 25,000 BC)
The Prince of Lilies, from the Bronze Age Palace of Minos at Knossos on Crete
Roman wall painting showing a dye shop, Pompeii (40 BC)
Inside cave 13B at Pinnacle Point, an archeological site found on the coast of South Africa, paleoanthropologists in 2000 found evidence that, between 170,000 and 40,000 years ago, Late Stone Age people were scraping and grinding ochre, a clay colored red by iron oxide, probably with the intention of using it to color their bodies.
Red hematite powder was also found scattered around the remains at a grave site in a Zhoukoudian cave complex near Beijing. The site has evidence of habitation as early as 700,000 years ago. The hematite might have been used to symbolize blood in an offering to the dead.
Red, black and white were the first colors used by artists in the Upper Paleolithic age, probably because natural pigments such as red ochre and iron oxide were readily available where early people lived. Madder, a plant whose root could be made into a red dye, grew widely in Europe, Africa and Asia. The cave of Altamira in Spain has a painting of a bison colored with red ochre that dates to between 15,000 and 16,500 BC.
A red dye called Kermes was made beginning in the Neolithic Period by drying and then crushing the bodies of the females of a tiny scale insect in the genus Kermes, primarily Kermes vermilio. The insects live on the sap of certain trees, especially Kermes oak trees near the Mediterranean region. Jars of kermes have been found in a Neolithic cave-burial at Adaoutse, Bouches-du-Rhône. Kermes from oak trees was later used by Romans, who imported it from Spain. A different variety of dye was made from Porphyrophora hamelii (Armenian cochineal) scale insects that lived on the roots and stems of certain herbs. It was mentioned in texts as early as the 8th century BC, and it was used by the ancient Assyrians and Persians.
Red hematite powder was also found scattered around the remains at a grave site in a Zhoukoudian cave complex near Beijing. The site has evidence of habitation as early as 700,000 years ago. The hematite might have been used to symbolize blood in an offering to the dead.
In ancient Egypt, red was associated with life, health, and victory. Egyptians would color themselves with red ochre during celebrations. Egyptian women used red ochre as a cosmetic to redden cheeks and lips and also used henna to color their hair and paint their nails.
The ancient Romans wore togas with red stripes on holidays, and the bride at a wedding wore a red shawl, called a flammeum. Red was used to color statues and the skin of gladiators. Red was also the color associated with army; Roman soldiers wore red tunics, and officers wore a cloak called a paludamentum which, depending upon the quality of the dye, could be crimson, scarlet or purple. In Roman mythology red is associated with the god of war, Mars. The vexilloid of the Roman Empire had a red background with the letters SPQR in gold. A Roman general receiving a triumph had his entire body painted red in honor of his achievement.
The Romans liked bright colors, and many Roman villas were decorated with vivid red murals. The pigment used for many of the murals was called vermilion, and it came from the mineral cinnabar, a common ore of mercury. It was one of the finest reds of ancient times – the paintings have retained their brightness for more than twenty centuries. The source of cinnabar for the Romans was a group of mines near Almadén, southwest of Madrid, in Spain. Working in the mines was extremely dangerous, since mercury is highly toxic; the miners were slaves or prisoners, and being sent to the cinnabar mines was a virtual death sentence.
The Middle Ages
Roman Catholic Popes wear red as the symbol of the blood of Christ. This is Pope Innocent III, in about 1219.
Red was the traditional color of martyrs. A Russian icon of Saint George (14th c.).
The colour of majesty - portrait of Charlemagne, King of the Franks and Holy Roman Emperor, Netherlands (14th c.)
After the fall of the Western Roman Empire, red was adopted as a color of majesty and authority by the Byzantine Empire, and the princes of Europe. It also played an important part in the rituals of the Roman Catholic Church, symbolizing the blood of Christ and the Christian martyrs.
In Western Europe, Emperor Charlemagne painted his palace red as a very visible symbol of his authority, and wore red shoes at his coronation. Kings, princes and, beginning in 1295, Roman Catholic cardinals began to wear red colored habitus. When Abbe Suger rebuilt Saint Denis Basilica outside Paris in the early 12th century, he added stained glass windows colored blue cobalt glass and red glass tinted with copper. Together they flooded the basilica with a mystical light. Soon stained glass windows were being added to cathedrals all across France, England and Germany. In medieval painting red was used to attract attention to the most important figures; both Christ and the Virgin Mary were commonly painted wearing red mantles.
In western countries red is a symbol of martyrs and sacrifice, particularly because of its association with blood. Beginning in the Middle Ages, the Pope and Cardinals of the Roman Catholic Church wore red to symbolize the blood of Christ and the Christian martyrs. The banner of the Christian soldiers in the First Crusade was a red cross on a white field, the St. George's Cross. According to Christian tradition, Saint George was a Roman soldier who was a member of the guards of the Emperor Diocletian, who refused to renounce his Christian faith and was martyred. The Saint George's Cross became the Flag of England in the 16th century, and now is part of the Union Flag of the United Kingdom, as well as the Flag of the Republic of Georgia.
Renaissance
The young Queen Elizabeth I (here in about 1563)
The Wedding Dance (1566), by Pieter Bruegel the Elder
The Girl with the Wine Glass, by Johannes Vermeer (1659–60)
Princess Anne of Denmark (later Queen Anne of Great Britain) (1685)
In Renaissance painting, red was used to draw the attention of the viewer; it was often used as the color of the cloak or costume of Christ, the Virgin Mary, or another central figure.
In Venice, Titian was the master of fine reds, particularly vermilion; he used many layers of pigment mixed with a semi-transparent glaze, which let the light pass through, to create a more luminous color. The figures of God, the Virgin Mary and two apostles are highlighted by their vermilion red costumes.
Queen Elizabeth I of England liked to wear bright reds, before she adopted the more sober image of the "Virgin Queen".
Red costumes were not limited to the upper classes. In Renaissance Flanders, people of all social classes wore red at celebrations. One such celebration was captured in The Wedding Dance (1566) by Pieter Bruegel the Elder.
The painter Johannes Vermeer skilfully used different shades and tints of vermilion to paint the red skirt in The Girl with the Wine Glass, then glazed it with madder lake to make a more luminous color.
Reds from the New World
Textiles dyed red from the Paracas culture of Peru (about 200 BC), in the British Museum
Feather headdress from the Aztec people of Mexico and Central America, dyed with cochineal
A native of Central America collecting cochineal insects from a cactus to make red dye (1777)
In Latin America, the Aztec people, the Paracas culture and other societies used cochineal, a vivid scarlet dye made from insects. From the 16th until the 19th century, cochineal became a highly profitable export from Spanish Mexico to Europe.
18th to 20th century
King Joseph I of Portugal (1773)
The Brazilian imperial family (1857)
King Edward VII of the United Kingdom (1901)
Red flag of the Bolsheviks, by Boris Kustodiev (1920)
Chinese honour guard, Beijing, 2007
In the 18th century, red began to take on a new identity as the colour of resistance and revolution. It was already associated with blood, and with danger; a red flag hoisted before a battle meant that no prisoners would be taken. In 1793-94, red became the colour of the French Revolution. A red Phrygian cap, or "liberty cap", was part of the uniform of the sans-culottes, the most militant faction of the revolutionaries.
In the late 18th century, during a strike English dock workers carried red flags, and it thereafter became closely associated with the new labour movement, and later with the Labour Party in the United Kingdom, founded in 1900.
In Paris in 1832, a red flag was carried by working-class demonstrators in the failed June Rebellion, an event immortalised in Les Misérables), and later in the 1848 French Revolution. The red flag was proposed as the new national French flag during the 1848 revolution, but was rejected by at the urging of the poet and statesman Alphonse Lamartine in favour of the tricolour flag. It appeared again as the flag of the short-lived Paris Commune in 1871. It was then adopted by Karl Marx and the new European movements of socialism and communism. Soviet Russia adopted a red flag following the Bolshevik Revolution in 1917. Communist China adopted the red flag following the Chinese Revolution of 1949. It was adopted by North Vietnam in 1954, and by all of Vietnam in 1975.
Symbolism
Courage and sacrifice
Surveys show that red is the color most associated with courage. In western countries red is a symbol of martyrs and sacrifice, particularly because of its association with blood. Beginning in the Middle Ages, the Pope and Cardinals of the Roman Catholic Church wore red to symbolize the blood of Christ and the Christian martyrs. The banner of the Christian soldiers in the First Crusade was a red cross on a white field, the St. George's Cross. According to Christian tradition, Saint George was a Roman soldier who was a member of the guards of the Emperor Diocletian, who refused to renounce his Christian faith and was martyred. The Saint George's Cross became the Flag of England in the 16th century, and now is part of the Union Flag of the United Kingdom, as well as the Flag of the Republic of Georgia.
Robert Gibb's 1881 painting, The Thin Red Line, depicting The Thin Red Line at the Battle of Balaclava (1854), when a line of the Scottish Highland infantry repulsed a Russian cavalry charge. The name was given by the British press as a symbol of courage against the odds.
The red poppy flower is worn on Remembrance Day in Commonwealth countries to honor soldiers who died in the First World War.
Hatred, anger, aggression, passion, heat and war
While red is the color most associated with love, it also the color most frequently associated with hatred, anger, aggression and war. People who are angry are said to "see red." Red is the color most commonly associated with passion and heat. In ancient Rome, red was the color of Mars, the god of war—the planet Mars was named for him because of its red color.
Warning and danger
Red is the traditional color of warning and danger, and is therefore often used on flags. In the Middle Ages up through the French Revolution, a red flag shown in warfare indicated the intent to take no prisoners. Similarly, a red flag hoisted by a pirate ship meant no mercy would be shown to their target. In Britain, in the early days of motoring, motor cars had to follow a man with a red flag who would warn horse-drawn vehicles, before the Locomotives on Highways Act 1896 abolished this law. In automobile races, the red flag is raised if there is danger to the drivers. In international football, a player who has made a serious violation of the rules is shown a red penalty card and ejected from the game.
Several studies have indicated that red carries the strongest reaction of all the colors, with the level of reaction decreasing gradually with the colors orange, yellow, and white, respectively. For this reason, red is generally used as the highest level of warning, such as threat level of terrorist attack in the United States. In fact, teachers at a primary school in the UK have been told not to mark children's work in red ink because it encourages a "negative approach".
Red is the international color of stop signs and stop lights on highways and intersections. It was standardized as the international color at the Vienna Convention on Road Signs and Signals of 1968. It was chosen partly because red is the brightest color in daytime (next to orange), though it is less visible at twilight, when green is the most visible color. Red also stands out more clearly against a cool natural backdrop of blue sky, green trees or gray buildings. But it was mostly chosen as the color for stoplights and stop signs because of its universal association with danger and warning. The 1968 Vienna Convention on Road Signs and Signals of 1968 uses red color also for the margin of danger warning sign, give way signs and prohibitory signs, following the previous German-type signage (established by Verordnung über Warnungstafeln für den Kraftfahrzeugverkehr in 1927).
The standard international stop sign, following the Vienna Convention on Road Signs and Signals of 1968
A footballer is shown a red card and ejected from a soccer match.
A red Chinese typhoon alert sign
Red is the color of a severe terrorist threat level in the United States, under the Homeland Security Advisory System.
Red is the color of extreme fire danger in Australia; new black/red stripes are an even more catastrophic hazard.
The color that attracts attention
Fashion model Magdalena Frackowiak at Paris Fashion Week (Fall 2011)
Red is the color that most attracts attention. Surveys show it is the color most frequently associated with visibility, proximity, and extroverts. It is also the color most associated with dynamism and activity.
Red is used in modern fashion much as it was used in Medieval painting; to attract the eyes of the viewer to the person who is supposed to be the center of attention. People wearing red seem to be closer than those dressed in other colors, even if they are actually the same distance away. Monarchs, wives of presidential candidates and other celebrities often wear red to be visible from a distance in a crowd. It is also commonly worn by lifeguards and others whose job requires them to be easily found.
Because red attracts attention, it is frequently used in advertising, though studies show that people are less likely to read something printed in red because they know it is advertising, and because it is more difficult visually to read than black and white text.
Seduction, sexuality and sin
Red by a large margin is the color most commonly associated with seduction, sexuality, eroticism and immorality, possibly because of its close connection with passion and with danger.
Red was long seen as having a dark side, particularly in Christian theology. It was associated with sexual passion, anger, sin, and the devil. In the Old Testament of the Bible, the Book of Isaiah said: "Though your sins be as scarlet, they shall be white as snow." In the New Testament, in the Book of Revelation, the Antichrist appears as a red monster, ridden by a woman dressed in scarlet, known as the Whore of Babylon.
Satan is often depicted as colored red and/or wearing a red costume in both iconography and popular culture. By the 20th century, the devil in red had become a folk character in legends and stories. The devil in red appears more often in cartoons and movies than in religious art.
In 17th-century New England, red was associated with adultery. In the 1850 novel by Nathaniel Hawthorne, The Scarlet Letter, set in a Puritan New England community, a woman is punished for adultery with ostracism, her sin represented by a red letter 'A' sewn onto her clothes.
Red is still commonly associated with prostitution. At various points in history, prostitutes were required to wear red to announce their profession. Houses of prostitution displayed a red light. Beginning in the early 20th century, houses of prostitution were allowed only in certain specified neighborhoods, which became known as red-light districts. Large red-light districts are found today in Bangkok and Amsterdam.
In the handkerchief code, the color red signifies interest in the sexual act of fisting.
In both Christian and Hebrew tradition, red is also sometimes associated with murder or guilt, with "having blood on one's hands", or "being caught red-handed.
The Whore of Babylon, depicted in a 14th-century French illuminated manuscript. The woman appears attractive, but is wearing red under her blue garment.
Reine de joie, (Queen of Joy), a book cover illustration by Henri de Toulouse-Lautrec (1892) about a Paris prostitute
Sheet music for "At the Devil's Ball", by Irving Berlin, United States, 1915
The red-light district in Amsterdam (2003). Red is the sex industry's preferred color in many cultures, due to being strongly associated with passion, love and sexuality.
Red lipstick has been worn by women as a cosmetic since ancient times. It was worn by Cleopatra, Queen Elizabeth I, and film stars such as Elizabeth Taylor and Marilyn Monroe.
In religion
In Christianity, red is associated with the blood of Christ and the sacrifice of martyrs. In the Roman Catholic Church it is also associated with pentecost and the Holy Spirit. Since 1295, it is the color worn by Cardinals, the senior clergy of the Roman Catholic Church. Red is the liturgical color for the feasts of martyrs, representing the blood of those who suffered death for their faith. It is sometimes used as the liturgical color for Holy Week, including Palm Sunday and Good Friday, although this is a modern (20th-century) development. In Catholic practice, it is also the liturgical color used to commemorate the Holy Spirit (for this reason it is worn at Pentecost and during Confirmation masses). Because of its association with martyrdom and the Spirit, it is also the color used to commemorate saints who were martyred, such as St. George and all the Apostles (except for the Apostle St. John, who was not martyred, where white is used). As such, it is used to commemorate bishops, who are the successors of the Apostles (for this reason, when funeral masses are held for bishops, cardinals, or popes, red is used instead of the white that would ordinarily be used).
In Buddhism, red is one of the five colors which are said to have emanated from the Buddha when he attained enlightenment, or nirvana. It is particularly associated with the benefits of the practice of Buddhism; achievement, wisdom, virtue, fortune and dignity. It was also believed to have the power to resist evil. In China red was commonly used for the walls, pillars, and gates of temples.
In the Shinto religion of Japan, the gateways of temples, called torii, are traditionally painted vermilion red and black. The torii symbolizes the passage from the profane world to a sacred place. The bridges in the gardens of Japanese temples are also painted red (and usually only temple bridges are red, not bridges in ordinary gardens), since they are also passages to sacred places. Red was also considered a color which could expel evil and disease.
In Taoism, red is sometimes used to symbolize yang.
In Chinese folk religion, red is also sometimes used to symbolize yang in the context of the creator Pangu, who hatched out of a cosmic egg colored like a taijitu. Some art of Pangu colored yang as red.
A Shinto torii at Itsukushima, Japan
Cardinals of the Roman Catholic Church at the funeral of Pope John Paul II
Buddhist monks in Tibet
In Hinduism, red is associated with Lakshmi, the goddess of wealth and embodiment of beauty.
Red flags in a celebration of Muharram in Iran
Military uses
Red uniform
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed.Find sources: "Red" – news · newspapers · books · scholar · JSTOR (July 2021) (Learn how and when to remove this template message)
The red military uniform was adopted by the English Parliament's New Model Army in 1645, and was still worn as a dress uniform by the British Army until the outbreak of the First World War in August 1914. Ordinary soldiers wore red coats dyed with madder, while officers wore scarlet coats dyed with the more expensive cochineal. This led to British soldiers being known as red coats.
In the modern British army, scarlet is still worn by the Foot Guards, the Life Guards, and by some regimental bands or drummers for ceremonial purposes. Officers and NCOs of those regiments which previously wore red retain scarlet as the color of their "mess" or formal evening jackets. The Royal Gibraltar Regiment has a scarlet tunic in its winter dress.
Scarlet is worn for some full dress, military band or mess uniforms in the modern armies of a number of the countries that made up the former British Empire. These include the Australian, Jamaican, New Zealand, Fijian, Canadian, Kenyan, Ghanaian, Indian, Singaporean, Sri Lankan and Pakistani armies.
The musicians of the United States Marine Corps Band wear red, following an 18th-century military tradition that the uniforms of band members are the reverse of the uniforms of the other soldiers in their unit. Since the US Marine uniform is blue with red facings, the band wears the reverse.
Red Serge is the uniform of the Royal Canadian Mounted Police, created in 1873 as the North-West Mounted Police, and given its present name in 1920. The uniform was adapted from the tunic of the British Army. Cadets at the Royal Military College of Canada also wear red dress uniforms.
The Brazilian Marine Corps wears a red dress uniform.
Officer and soldier of the British Army, 1815
The scarlet uniform of the National Guards Unit of Bulgaria
Musicians of the United States Marine Corps Band
Officer of the Royal Canadian Mounted Police
The Brazilian Marine Corps wears a dress uniform called A Garança.
Soldiers of the Rajput Regiment of the Indian Army
NATO Military Symbols for Land Based Systems uses red to denote hostile forces, hence the terms "red team" and "Red Cell" to denote challengers during exercises.
In sports
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed.Find sources: "Red" – news · newspapers · books · scholar · JSTOR (July 2021) (Learn how and when to remove this template message)
The first known team sport to feature red uniforms was chariot racing during the late Roman Empire. The earliest races were between two chariots, one driver wearing red, the other white. Later, the number of teams was increased to four, including drivers in light green and sky blue. Twenty-five races were run in a day, with a total of one hundred chariots participating.
Today many sports teams throughout the world feature red on their uniforms. Along with blue, red is the most commonly used non-white color in sports. Numerous national sports teams wear red, often through association with their national flags. A few of these teams feature the color as part of their nickname such as Spain (with their association football (soccer) national team nicknamed La Furia Roja or "The Red Fury") and Belgium (whose football team bears the nickname Rode Duivels or "Red Devils").
In club association football (soccer), red is a commonly used color throughout the world. Among European notable club teams most often playing at home in red shirts include Bayern Munich, Benfica, Liverpool, Manchester United and Roma. Furthermore, many prominent teams play in partially red color schemes, involving different-colored sleeves or stripes. A number of teams' nicknames feature the color. A red penalty card is issued to a player who commits a serious infraction: the player is immediately disqualified from further play and his team must continue with one fewer player for the game's duration.
Rosso Corsa is the red international motor racing color of cars entered by teams from Italy. Since the 1920s Italian race cars of Alfa Romeo, Maserati, Lancia, and later Ferrari and Abarth have been painted with a color known as rosso corsa ("racing red"). National colors were mostly replaced in Formula One by commercial sponsor liveries in 1968, but unlike most other teams, Ferrari always kept the traditional red, although the shade of the color varies. Ducati traditionally run red factory bikes in motorcycle World Championship racing.
The color is commonly used for professional sports teams in Canada and the United States with eleven Major League Baseball teams, eleven National Hockey League teams, seven National Football League teams and eleven National Basketball Association teams prominently featuring some shade of the color. The color is also featured in the league logos of Major League Baseball, the National Football League and the National Basketball Association. In the National Football League, a red flag is thrown by the head coach to challenge a referee's decision during the game. During the 1950s when red was strongly associated with communism in the United States, the modern Cincinnati Reds team was known as the "Redlegs" and the term was used on baseball cards. After the red scare faded, the team was known as the "Reds" again.
In boxing, red is often the color used on a fighter's gloves. George Foreman wore the same red trunks he used during his loss to Muhammad Ali when he defeated Michael Moorer 20 years later to regain the title he lost. Boxers named or nicknamed "red" include Red Burman, Ernie "Red" Lopez, and his brother Danny "Little Red" Lopez.
Ancient Roman mosaic of the winner of a chariot race, wearing the colors of the red team
Both the Cleveland Indians and the Boston Red Sox wear red.
In martial arts, a red belt shows a high degree of proficiency, second only, in some schools, to the black belt.
An Alfa Romeo Sports Racing car in 1977, painted Rosso Corsa ("racing red"), the traditional racing color of Italy from the 1920s until the late 1960s.
On flags
See also: Red flag (politics)
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed.Find sources: "Red" – news · newspapers · books · scholar · JSTOR (July 2021) (Learn how and when to remove this template message)
Countries with red on their flags; the shades of red correspond to those on their respective flags.
Red is the most common color found in national flags, found on the flags of 77 percent of the 210 countries listed as independent in 2016; far ahead of white (58 percent); green (40 percent) and blue (37 percent). The British flag bears the colors red, white and blue; it includes the cross of Saint George, patron saint of England, and the saltire of Saint Patrick, patron saint of Ireland, both of which are red on white. The flag of the United States bears the colors of Britain, the colors of the French tricolore include red as part of the old Paris coat of arms, and other countries' flags, such as those of Australia, New Zealand, and Fiji, carry a small inset of the British flag in memory of their ties to that country. Many former colonies of Spain, such as Mexico, Colombia, Costa Rica, Cuba, Ecuador, Panama, Peru, Puerto Rico and Venezuela, also feature red-one of the colors of the Spanish flag-on their own banners. Red flags are also used to symbolize storms, bad water conditions, and many other dangers.
The red on the flag of Nepal represents the floral emblem of the country, the rhododendron.
Red, blue, and white are also the Pan-Slavic colors adopted by the Slavic solidarity movement of the late nineteenth century. Initially these were the colors of the Russian flag; as the Slavic movement grew, they were adopted by other Slavic peoples including Slovaks, Slovenes, and Serbs. The flags of the Czech Republic and Poland use red for historic heraldic reasons (see Coat of arms of Poland and Coat of arms of the Czech Republic) & not due to Pan-Slavic connotations. In 2004 Georgia adopted a new white flag, which consists of four small and one big red cross in the middle touching all four sides.
Red, white, and black were the colors of the German Empire from 1870 to 1918, and as such they came to be associated with German nationalism. In the 1920s they were adopted as the colors of the Nazi flag. In Mein Kampf, Hitler explained that they were "revered colors expressive of our homage to the glorious past." The red part of the flag was also chosen to attract attention – Hitler wrote: "the new flag ... should prove effective as a large poster" because "in hundreds of thousands of cases a really striking emblem may be the first cause of awakening interest in a movement." The red also symbolized the social program of the Nazis, aimed at German workers. Several designs by a number of different authors were considered, but the one adopted in the end was Hitler's personal design.
Red, white, green and black are the colors of Pan-Arabism and are used by many Arab countries.
Red, gold, green, and black are the colors of Pan-Africanism. Several African countries thus use the color on their flags, including South Africa, Ghana, Senegal, Mali, Ethiopia, Togo, Guinea, Benin, and Zimbabwe. The Pan-African colors are borrowed from the flag of Ethiopia, one of the oldest independent African countries. Rwanda, notably, removed red from its flag after the Rwandan genocide because of red's association with blood.
The flags of Japan and Bangladesh both have a red circle in the middle of different colored backgrounds. The flag of the Philippines has a red trapezoid on the bottom signifying blood, courage, and valor (also, if the flag is inverted so that the red trapezoid is on top and the blue at the bottom, it indicates a state of war). The flag of Singapore has a red rectangle on the top. The field of the flag of Portugal is green and red. The Ottoman Empire adopted several different red flags during the six centuries of its rule, with the successor Republic of Turkey continuing the 1844 Ottoman flag.
The flag of the Byzantine Empire from 1260 to its fall in 1453
The St George's cross was the banner of the First Crusade, then, beginning in the 13th century, the flag of England. It is the red color (along with that of the Cross of Saint Patrick) in the flag of the United Kingdom, and, by adoption, of the red in the flag of the United States.
The red stripes in the flag of the United States were adapted from the flag of the British East India Company. This is the Grand Union Flag, the first U.S. flag established by the Continental Congress.
The Flag of Georgia also features the Saint George's Cross. It dates back to the banner of Medieval Georgia in the 5th century.
The maple leaf flag of Canada, adopted in 1965. The red color comes from the Saint George's Cross of England.
In politics
This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed.Find sources: "Red" – news · newspapers · books · scholar · JSTOR (July 2021) (Learn how and when to remove this template message)
The red Phrygian cap worn by sans-culottes during the French Revolution
Logo of the German Social Democratic Party
In 18th-century Europe, red was usually associated with the monarchy and with those in power. The Pope wore red, as did the Swiss Guards of the Kings of France, the soldiers of the British Army and the Danish Army.
In the Roman Empire, freed slaves were given a red Phrygian cap as an emblem of their liberation. Because of this symbolism, the red "Liberty cap" became a symbol of the American patriots fighting for independence from England. During the French Revolution, the Jacobins also adapted the red Phrygian cap, and forced the deposed King Louis XVI to wear one after his arrest.
Socialism and communism
In the 19th century, with the Industrial Revolution and the rise of worker's movements, red became the color of socialism (especially the Marxist variant), and, with the Paris Commune of 1871, of revolution.
In the 20th century, red was the color first of the Russian Bolsheviks and then, after the success of the Russian Revolution of 1917, of communist parties around the world. However, after the fall of the Soviet Union in 1991, Russia went back to the pre-revolutionary blue, white and red flag.
Red also became the color of many social democratic parties in Europe, including the Labour Party in Britain (founded 1900); the Social Democratic Party of Germany (whose roots went back to 1863) and the French Socialist Party, which dated back under different names, to 1879. The Socialist Party of America (1901–72) and the Communist Party USA (1919) both also chose red as their color.
Members of the Christian-Social People's Party in Liechtenstein (founded 1918) advocated an expansion of democracy and progressive social policies, and were often referred to disparagingly as "Reds" for their social liberal leanings and party colors.
The Chinese Communist Party, founded in 1920, adopted the red flag and hammer and sickle emblem of the Soviet Union, which became the national symbols when the Party took power in China in 1949. Under Party leader Mao Zedong, the Party anthem became "The East Is Red", and Mao Zedong himself was sometimes referred to as a "red sun". During the Cultural Revolution in China, Party ideology was enforced by the Red Guards, and the sayings of Mao Zedong were published as a little red book in hundreds of millions of copies. Today the Chinese Communist Party claims to be the largest political party in the world, with eighty million members.
Beginning in the 1960s and the 1970s, paramilitary extremist groups such as the Red Army Faction in Germany, the Japanese Red Army and the Shining Path Maoist movement in Peru used red as their color. But in the 1980s, some European socialist and social democratic parties, such as the Labour Party in Britain and the Socialist Party in France, moved away from the symbolism of the far left, keeping the red color but changing their symbol to a less-threatening red rose.
Red is used around the world by political parties of the left or center-left. In the United States, it is the color of the Communist Party USA, of the Social Democrats, USA, and in Puerto Rico, of the Popular Democratic Party.
United States
A map of the U.S. showing the blue states, which voted for the Democratic candidate in the 2008, 2012, 2016, and 2020 presidential elections, and the red states, which voted for the Republican Party
In the United States, political commentators often refer to the "red states", which voted for Republican candidates in the last four presidential elections, and "blue states", which voted for Democrats. This convention is relatively recent: before the 2000 presidential election, media outlets assigned red and blue to both parties, sometimes alternating the allocation for each election. Fixed usage was established during the 39-day recount following the 2000 election, when the media began to discuss the contest in terms of "red states" versus "blue states". States which voted for different parties in two of the last four presidential elections are called "Swing States", and are usually coloured purple, a mix of red and blue.
Social and special interest groups
Such names as Red Club (a bar), Red Carpet (a discothèque) or Red Cottbus and Club Red (event locations) suggest liveliness and excitement. The Red Hat Society is a social group founded in 1998 for women 50 and over. Use of the color red to call attention to an emergency situation is evident in the names of such organizations as the Red Cross (humanitarian aid), Red Hot Organization (AIDS support), and the Red List of Threatened Species (of IUCN). In reference to humans, term "red" is often used in the West to describe the indigenous peoples of the Americas.
Idioms
Many idiomatic expressions exploit the various connotations of red:
Expressing emotion
"to see red" (to be angry or aggressive)
"to have red ears / a red face" (to be embarrassed)
"to paint the town red" (to have an enjoyable evening, usually with a generous amount of eating, drinking, dancing)
Giving warning
"to raise a red flag" (to signal that something is problematic)
"like a red rag to a bull" (to cause someone to be enraged)
"to be in the red" (to be losing money, from the accounting convention of writing deficits and losses in red ink)
Calling attention
"a red letter day" (a special or important event, from the medieval custom of printing the dates of saints' days and holy days in red ink.)
"to roll out the red carpet" (to formally welcome an important guest)
"to give red-carpet treatment" (to treat someone as important or special)
"to catch someone red-handed" (to catch or discover someone doing something bad or wrong)
Other idioms
"to tie up in red tape". In England red tape was used by lawyers and government officials to identify important documents. It became a term for excessive bureaucratic regulation. It was popularized in the 19th century by the writer Thomas Carlyle, who complained about "red-tapism".
"red herring". A false clue that leads investigators off the track. Refers to the practice of using a fragrant smoked fish to distract hunting or tracking dogs from the track they are meant to follow.
"red ink" (to show a business loss)
See also
Blushing
Lists of colors
Little Red Riding Hood
Red flag (politics)
Red pigments | biology | 13355 | https://da.wikipedia.org/wiki/R%C3%B8d | Rød | Rød er en farve. Rødt lys har en bølgelængde på 647-723 nm.
Symbolik
Inden for kristendommen hentyder farven til Kristi lidelse og Helligåndens ild. I kirken bruges den som liturgisk farve i pinsen og anden juledag. Rødt i forbindelse med korset symboliserer Jesus blod.
Rød kan også symbolisere Satan,Helvede, liderlighed og hovmod.
Af Israels tolv stammer er rød tilknyttet Juda og Ruben.
Det er kardinalernes farve i Vatikanet, og inden for den katolske kirke symboliserer rødt martyrernes blod.
De indiske modergudinder repræsenteredes ved rødt. I Egypten blev rød sat i forbindelse med guden Seth (kaos) og den fjendtlige Apophis slange. Hos mayafolket forestillede den øst, hos højlandsfolket i det gamle Mexico.
I Kina var det den hellige, livgivende farve.
I alkymien forbindes rødt med hvidt som et modsætningspar, og symboliserer det materielle princip Sulphur, det brændende.
Stjernetegnet vædderens farve er rød
Uden kontekst
Udsagn der mangler angivelse af kontekst, og derfor ikke kan tages alvorligt.
Rød forbindes med blod, hjerte, liv, lidenskab, stærke følelser, varme, hede, ild, opofrelse og fare. Den står for aggressivitet og vitalitet.
Det er kærlighedens farve, men også hadets og raseriets. Det er kampens, krigens og dermed også militærets farve. Romerne brugte rød som symbol for magten, kejseren, adelen og krigerne. Farven er tilknyttet krigsguden Mars. Den kan symbolisere revolution, socialisme, kommunisme (røde faner).
I oldtiden mente man at rødt beskyttede mod farer.
Rod-chakraets farve er rød, og står for jordforbindelsen, det fysiske fundament og den fysiske krop. I drømme kan den røde farve fortælle nogen om følelses-funktionen.
Rød er også i naturens sammenhæng et udtryk for fare og advarsel. I kombination med gul og sort er dette især hos dyr et udtryk for giftighed.
Anvendelse
Fra starten på international motorsport og indtil 1960'erne blev grøn anvendt som international racingfarve på britiske biler. Nuancen kaldes British racing green.
Inden for politik er rød farven for socialisme og kommunisme. I amerikansk politik er rød dog farven for det republikanske parti, der ikke er hverken socialistiske eller kommunistiske.
I trafikken betyder det stop, røde lygter betyder optaget.
Fodnoter
Farver | danish | 0.541227 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.