diff --git "a/49A0T4oBgHgl3EQfNv86/content/tmp_files/load_file.txt" "b/49A0T4oBgHgl3EQfNv86/content/tmp_files/load_file.txt" new file mode 100644--- /dev/null +++ "b/49A0T4oBgHgl3EQfNv86/content/tmp_files/load_file.txt" @@ -0,0 +1,1007 @@ +filepath=/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf,len=1006 +page_content='MNRAS 000, 1–18 (222) Preprint 6 January 2023 Compiled using MNRAS LATEX style file v3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0 A Gaian Habitable Zone Rudy Arthur,1★ Arwen Nicholson,2† 1University of Exeter, Department of Computer Science 2University of Exeter, Department of Physics and Astronomy Accepted XXX.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Received YYY;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' in original form ZZZ ABSTRACT When searching for inhabited exoplanets, understanding the boundaries of the habitable zone around the parent star is key.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' If life can strongly influence its global environment, then we would expect the boundaries of the habitable zone to be influenced by the presence of life.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Here using a simple abstract model of ‘tangled-ecology’ where life can influence a global parameter, labelled as temperature, we investigate the boundaries of the habitable zone of our model system.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' As with other models of life-climate interactions, the species act to regulate the temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' However, the system can also experience ‘punctuations’, where the system’s state jumps between different equilibria.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Despite this, an ensemble of systems still tends to sustain or even improve conditions for life on average, a feature we call Entropic Gaia.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The mechanism behind this is sequential selection with memory which is discussed in detail.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' With this modelling framework we investigate questions about how Gaia can affect and ultimately extend the habitable zone to what we call the Gaian habitable zone.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This generates concrete predictions for the size of the habitable zone around stars, suggests directions for future work on the simulation of exoplanets and provides insight into the Gaian bottleneck hypothesis and the habitability/inhabitance paradox.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Key words: Gaia – Habitable Zone – Biosignatures 1 INTRODUCTION The Gaia hypothesis is that life influences the Earth’s feedback mech- anisms to form a self-regulating system, and therefore life can help maintain habitable conditions on its host planet Lovelock & Mar- gulis (1974).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Distinct from the biosphere Huggett (1999), Gaia is the whole life-earth system, considered as a single entity.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The impor- tance of life’s interactions with the non-living environment are now common sense, and the discipline of Earth System Science Lenton & Watson (2013) studies the various feedback loops that constitute ‘Gaia’s body’ Volk (2012).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Gaia theory itself takes a very broad perspective, aiming to describe life at a planetary scale.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Gaia theory asks questions like: Is Gaia inevitable on a planet that hosts life, or is it due to chance?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' What mechanisms can create a long lived Gaian system?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' How will we detect other ‘Gaias’ beyond our solar system, where direct planetary exploration is not an option?' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The astrophysical point of view was crucial in the early development of Gaia, with the search for life on Mars providing the initial inspiration for the Gaia hypothesis Lovelock (1965).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' When looking at Earth from afar, Gaia is what we see and the search for habitable or inhabited exoplanets is the search for other Gaias.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Methods for exoplanet detection have developed considerably since Gaia was first proposed.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' New telescopes, such as the James Webb Space telescope and the Extremely Large Telescope (currently under construction), and future missions, such as the Large Ultravi- olet Optical Infrared Surveyor, mean that searching for signs of alien ★ E-mail: R.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='Arthur@exeter.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='ac.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='uk † E-mail: A.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='E.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='Nicholson@exeter.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='ac.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='uk life will be possible within the coming decades Snellen et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2021);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Quanz et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2021).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' While robotic missions to potentially habitable exoplanets remain unfeasible, evidence for alien life will only be ob- servable for exoplanets that have been dramatically shaped by their biospheres.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Exoplanets with newly emerging life, or those with the remnants of a once-thriving biosphere that has since collapsed, will be unlikely to produce a remotely observable signature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Answering the key questions of Gaia theory not only informs how we think about the history of life on Earth, but can form the theoretical foundation for the study of life in the universe.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Catling et.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Catling et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018) proposed a framework for as- sessing potential biosignatures using a probabilistic approach that combines observations of the candidate planet and host star with models of the possible abiotic and biotic planetary processes to de- termine the probability of the planet being inhabited.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' With a great diversity of exoplanets being found, any potential biosignature must be considered within the context of its host planet Seager (2013);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Claudi.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2017);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Kiang et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Schwieterman et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Krissansen-Totton et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2022).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Detailed abiotic models of exoplan- ets are being developed for a wide range of detected planets, see e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Amundsen et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2016);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Boutle et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2017);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Collins (2021);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Fauchez et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2021), and sophisticated models of biogeochemistry exist for different points in Earth’s history, e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Kharecha et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2005);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Daines et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2017);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Lenton et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018b);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Zakem et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2020).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Detailed and realistic modelling of life on other planets is im- portant, however this paper will take a broader view that aims to understand the generic mechanisms that lead to Gaia.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We build on recent work Ford Doolittle (2014);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Lenton et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018a);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Arthur & Nicholson (2022) on Gaian selection principles.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We argued in © 222 The Authors arXiv:2301.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='02150v1 [astro-ph.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='EP] 5 Jan 2023 2 Arthur & Nicholson Arthur & Nicholson (2022) that some approaches to Gaian selec- tion Ford Doolittle (2014);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Lenton et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018a) lead to anthropic reasoning - we see Gaia because if we didn’t we wouldn’t exist.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' An- thropic reasoning is controversial, with its opponents arguing that it unfalsifiable with limited (if any) predictive power Smolin (2007).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The coming era of exoplanet astronomy gives new context and pur- pose to these discussions.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' If our aim is for Gaia theory to inform our search for life in the universe, then anthropic arguments are clearly inadequate.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In Arthur & Nicholson (2022) we argue for ‘Entropic Gaia’ - that the emergence of Gaia is a statistical tendency for planets that host life.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This means that life history on a single planet can be chaotic and have periods of stability and collapse, however there is a trend towards increasing biomass, stability, habitability and other Gaian features.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Any single planetary history for a life-bearing planet, such as Earth, is likely to follow a (bumpy) trajectory towards Gaia.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The micro-mechanism leading to this behaviour was argued to be ‘Se- quential Selection with Memory’ or an ‘entropic ratchet’.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In brief, this mechanism starts from the observation that coupled life-environment systems move between regulation and disregulation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' By definition, disregulating systems quickly destroy themselves while regulating systems persist, this is sequential selection Lenton et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018a).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In models of ecology and Gaia (e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Becker & Sibani (2014);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Hard- ing (1999)) increasing diversity and complexity is associated with increasing stability 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' More diverse ecosystems can generate more novel species through mutation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Thus after every ecosystem collapse (caused by internal or external factors) if a new ecosystem arises it is likely to be more diverse, having started with a greater ‘pool’ of species, and therefore also more stable.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Sequential selection with memory describes a sequence of distinct stable states that tends to get ‘more Gaian’ over time.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This mechanism was originally proposed in the framework of the Tangled Nature Model (TNM) Christensen et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2002).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Originally designed to study co-evolution, we demonstrated in Arthur & Nichol- son (2017) that the TNM is closely related to the generalised Lotka- Volterra model.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The TNM is based on the idea that the growth rate of a species is given by a fitness function that depends on the other species present.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Any model making this assumption will look like the TNM close to equilibrium Arthur & Nicholson (2022).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' By studying the model with agent based dynamics we can incorporate mutation, giving us a very flexible, robust and general model of evolutionary ecology.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Since the TNM is quite general, conclusions drawn in this framework are likely to have general applicability.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Artificial life modelling has been used extensively to study Gaia.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The original Daisy World Watson & Lovelock (1983) led to a large number of variants Wood et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2008) and there are a variety of other models such as the Guild Model Downing & Zvirinsky (1999), Greenhouse World Worden (2010), Flask Model Williams & Lenton (2007) and Exo-Gaia Nicholson et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018) to name a few.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We have previously discussed Gaian models based on the TNM in Arthur & Nicholson (2017, 2022).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Here we propose a new variant on the TNM that is more similar to other Gaian models with a very simple abiotic (non-living) component.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' While previous Gaian models have included mutation (such as the Flask model and ExoGaia) the complexity of the biosphere in these models has been limited and different species within the mod- els only impact one another via the shared environment, e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' via 1 See Landi et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018) for a thorough discussion of the relationship be- tween ecosystem complexity and stability, though most of these models don’t consider coupling to the external environment resource competition or via global parameters such as temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' When we look at life on Earth it is clear that different species can have a large impact on each other beyond resource competition or changing global parameters like temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' For example, there are complex interactions between worms, plants and soil that change the structure, chemistry, water retention and other properties of soil for the benefit of many species Le Bayon et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2021).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' These kinds of symbiotic (and also antagonistic) interactions are usually missing in Gaian models.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We also observe that throughout Earth history there have been dramatic and spontaneous changes in the diversity and complexity of the biosphere, e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' the Great Oxidation Event which allowed for aerobic respiration to become an important energy source for life Ligrone (2019).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' These types of events, crucial for the selec- tion mechanism discussed above, are absent in other Gaian models.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In contrast, TNM species interact directly through antagonistic or symbiotic inter-species couplings, the population varies consider- ably due to spontaneously occurring ‘quakes’ and there is no rigid upper bound on the population.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Thus by combining elements of the TNM with elements of earlier Gaian models we can explore how Ga- ian regulation emerges within a system that allows for more complex ecosystem dynamics.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' With this model we hope to show that the arguments for Entropic Gaia are robust by demonstrating how they work in a setting where life needs to interact with and regulate an external environment.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' At the same time we will explore how Gaia can inform the search for life in the universe, in particular how Gaia predicts a larger ‘habitable-zone’.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In section 2 we describe the model and how we add temperature, which is a combination of abiotic and biotic components.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In section 3 we study the model at constant background temperature to understand how temperature is regulated and interacts with the spontaneous ‘quakes’ that occur in the TNM.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Section 4 discusses the changes to the habitable-zone in the presence of life and section 5 studies how life adapts to deteriorating abiotic conditions.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Finally we conclude in section 6.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 2 MODEL DESCRIPTION 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='1 The Tangled Nature Model We start, as in Arthur & Nicholson (2022), with the generalised Lotka-Volterra model 𝑑𝑁𝑖 𝑑𝑡 = 𝑁𝑖 𝑓𝑖(�𝑛, 𝑁) (1) 𝑁𝑖 is the population of species 𝑖, 𝑁 is the total population and 𝑛𝑖 = 𝑁𝑖 𝑁 .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 𝑓𝑖 is a fitness function that depends on the type and abundance of the other species present through �𝑛 = (𝑛1, 𝑛2, .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' , 𝑛𝐷) and 𝑁.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We can expand 𝑓𝑖 to linear order around the equilibrium at 𝑁 = 0 𝑑𝑁𝑖 𝑑𝑡 = 𝑁𝑖 � 𝑓𝑖(�0, 0) + ∑︁ 𝑗 𝑑𝑓𝑖 𝑑𝑛 𝑗 (�0, 0)𝑛 𝑗 + 𝑑𝑓𝑖 𝑑𝑁 (�0, 0)𝑁 .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' .' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' � (2) The summations here and for the rest of this paper are over all extant species.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The three terms on the right hand side are the basic TNM variables.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 𝑟𝑖 ≡ 𝑓𝑖(�0, 0) is the growth rate of species 𝑖 in the absence of any other species.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We set this to zero, meaning that one species’ growth depends entirely on the other species present.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We could add some species with non-zero growth rates to represent primary producers but for simplicity and consistency with the rest of the TNM literature every species has 𝑟𝑖 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' MNRAS 000, 1–18 (222) A Gaian Habitable Zone 3 𝐽𝑖 𝑗 ≡ 𝑑 𝑓𝑖 𝑑𝑛𝑗 (�0, 0) is the inter-species coupling matrix where 𝐽𝑖 𝑗 is the effect of species 𝑗 on species 𝑖.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' As usual Christensen et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2002), we set the elements randomly from a symmetric distribution.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Here each element 𝐽𝑖 𝑗 is randomly chosen from a standard normal product distribution times 𝑐 = 100.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The exact functional form of the distribution is not important, only that it has infinite support Arthur et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2017).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' −𝜇 ≡ 𝑑 𝑓𝑖 𝑑𝑁 (�0, 0) is the inverse carrying capacity, controlling how much of the global ‘resource’ is consumed by each individual.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The growth equation now looks like 𝑑𝑁𝑖 𝑑𝑡 = 𝑁𝑖 �� � ∑︁ 𝑗 𝐽𝑖 𝑗𝑛 𝑗 − 𝜇𝑁�� � = 𝑁𝑖 𝑓 𝑇 𝑁 𝑀 𝑖 (3) In Arthur & Nicholson (2022) we added higher order terms to the fitness function and argued that these could be interpreted as species-environment interactions, since their net effect was to modify the 𝜇 term to create an “effective” carrying capacity.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This kind of ‘endogenous’ environment (e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' roughly analogous to atmospheric composition or oceanic pH) is in contrast to most Gaian models which represent the environment through one or more ‘exogenous’ parameters, which the model agents aim to regulate.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Daisyworld is the paradigmatic example, where black and white daisies spontaneously regulate a rising global temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We want to study this type of regulation in the TNM framework and only deal with an abiotic environment so, for simplicity, we do not include the higher order terms.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' While this is a common approach in Gaian modelling it is worth some consideration.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' It was shown in Arthur & Nicholson (2022) and Arthur & Nicholson (2017) that selection in the TNM tends to pro- duce beneficial endogenous/biotic environments.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' If we included both an abiotic and a biotic environment, TNM agents would be subject to more selective pressure i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' they would need to avoid degrading the external parameters (temperature) and internal parameters (∼ pH).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In Arthur & Nicholson (2017) it was noted that environmental selection isrelatively weak, because whennewspecies occurtheystart with low populations and therefore minimal impact on the environment.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This must also be the case for an abiotic environment.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Ultimately the rela- tive weighting of each in the fitness function would determine which environmental parameters are most ‘optimised’.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Studying these ef- fects is interesting but we leave it for future work, focusing here on understanding the model with a purely exogenous environment.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='2 Adding Temperature To add temperature to the TNM we let the global temperature 𝑇 be the sum of abiotic and biotic components: 𝑇 = 𝑇0 + 𝑇𝑙𝑖 𝑓 𝑒 (4) 𝑇0 is the temperature in the absence of life and𝑇𝑙𝑖 𝑓 𝑒 is the effect of the extant species in the model on the temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Every individual of species𝑖 has an effect, 𝐻𝑖, on the global temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The values of 𝐻𝑖 will be selected from a normal distribution with mean 0 and standard deviation 𝜎𝐻 , so species are equally likely to have a warming or cooling effect.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The total effect of life on the temperature is ∑︁ 𝑖 𝐻𝑖𝑁𝑖 (5) We describe how � 𝑖 𝐻𝑖𝑁𝑖 is related to 𝑇𝑙𝑖 𝑓 𝑒 in the next section.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We make the reproduction rate depend on the temperature by modifying the fitness function to 𝑓 𝑇 𝑁 𝑀 𝑖 (𝑇) = ∑︁ 𝑗 𝐽𝑖 𝑗 1 + �𝑇 −𝑇𝑃 𝜏 �2 𝑛 𝑗 − 𝜇𝑁 (6) 𝑇𝑃 is the preferred temperature and 𝜏 is a tolerance parameter.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The functional form is chosen so that at temperatures, 𝑇, far from 𝑇𝑃 the interaction strength is reduced, for example at 𝑇 = 𝑇𝑃 + 𝜏 the inter-species interaction strength is halved.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The functional form 1 1+𝑥2 is chosen for simplicity, any function that applies a smooth and symmetric temperature ‘window’ would work.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We have chosen 𝑇𝑃 and 𝜏 to be constant for all species and interactions.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We could, for example, make the width different for every inter-species interaction: 𝜏 → 𝜏𝑖 𝑗 and similarly for 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In the interest of keeping this work relatively brief and in line with other work such as the original Daisyworld model Watson & Lovelock (1983), Flask model Williams & Lenton (2007) and ExoGaia Nicholson et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2018), we use a constant 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' By keeping 𝑇𝑃 constant for all species we can focus on and highlight life’s impact on its environment.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' If 𝑇𝑃 is kept constant, then any improvement to a “planet’s” survival rate when including life-environment interaction can only come from life improving its environment rather than life simply adapting to it.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' As this is the part of Gaia theory that is less well accepted Kirchner (2003) it makes sense to explore scenarios where this effect isn’t potentially obscured by species adaptation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='3 Running the Model We solve the growth equation using agent based dynamics.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This means that we generate individual agents whose reproduction rate is controlled by the fitness function 𝑓 𝑇 𝑁 𝑀 𝑖 (𝑇).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Each agent is an individual of some species𝑖 and each agent’s reproduction probability is given by 𝑝𝑜 𝑓 𝑓 𝑖 = 1 1 + 𝑒− 𝑓 𝑇 𝑁 𝑀 𝑖 (𝑇 ) (7) The basic dynamics of the model are then (see also Arthur et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2017)): (i) Choose an individual and, with probability 𝑝𝑜 𝑓 𝑓 𝑖 , make a copy of that individual.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The copying step is meant to mimic asexual reproduction.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We take the 𝐿 = 20 bit binary representation of the species-index 𝑖 and copy one bit at a time, with a probability 𝑝𝑚𝑢𝑡 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='01 to flip a bit during each copy operation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (ii) Chose a random individual and kill it with probability 𝑝𝑘𝑖𝑙𝑙 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='1 𝐿 is the genome length, where the value of 20 is standard Christensen et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2002), meaning that the model can generate 2𝐿 ∼ 106 unique species.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' A ‘generation’ is the time required to iterate over the basic reproduction/death loop above 𝑁/𝑝𝑘𝑖𝑙𝑙 times, where this number is recalculated at the end of each generation.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This means in each generation every individual has had a chance to be selected once on average for a birth/death process.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' To update the temperature we perform the following steps after every generation If required, update the abiotic temperature 𝑇0 (see Section 5).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Update 𝑇𝑙𝑖 𝑓 𝑒 using 𝑇𝑙𝑖 𝑓 𝑒(𝑡) = 𝜆𝑇𝑙𝑖 𝑓 𝑒(𝑡 − 1) + (1 − 𝜆) ∑︁ 𝑖 𝐻𝑖𝑁𝑖 (8) Set 𝑇 = 𝑇0 + 𝑇𝑙𝑖 𝑓 𝑒 MNRAS 000, 1–18 (222) 4 Arthur & Nicholson Variable Symbol Value Inverse carrying capacity 𝜇 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='1 Mutation rate 𝑝𝑚𝑢𝑡 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='01 Death rate 𝑝𝑘𝑖𝑙𝑙 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='1 Lag parameter 𝜆 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='9 Preferred temperature 𝑇𝑃 100 Temperature tolerance 𝜏 2 Temperature effect 𝜎𝐻 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='05 Table 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' A list of all the key parameters in the model and the values we choose.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The model has a large parameter space and the parameters are set to convenient values used in previous work on the TNM.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The qualitative behaviour of the model is very robust to variations in these parameter values Christensen et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2002);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Arthur et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2017).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Here 𝑡 is the generation number, the timescale in this model and 𝜆 is a lag-parameter that stops the temperature from changing instan- taneously.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This mimics the real behaviour of the Earth-system, e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' climate models have demonstrated a lag in the response of surface temperatures over the ocean due to changes in atmospheric 𝐶𝑂2 Boucher et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2012).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The model is initialised with 500 individuals of a randomly chosen species and all averages are taken over 1000 model runs using different random seeds.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 3 CONSTANT TEMPERATURE EXPERIMENTS First we run the model with constant𝑇0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Figure 1 shows the behaviour of the population and temperature in one ‘run’ of the model for 104 generations.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The basic features of the standard TNM - quasi- stable states punctuated by sharp transitions - persist Christensen et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2002).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The important features of ‘core’ and ‘cloud’ Becker & Sibani (2014) are are retained as can be seen in Figure 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The core species are the only ones with significant population and these are the primary drivers of the temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The cloud species are mutants with small populations and random positive and negative effects on the temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' These two runs show that life can move the temperature away from 𝑇𝑃 or towards it, the question is what happens on average, in the long run.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Figures 3 (a) and (b) show the average population and average temperature for 𝑇0 = 100 = 𝑇𝑃 and 𝑇0 = 105 = 𝑇𝑃 + 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='5𝜏 respec- tively.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' For (a) 𝑇0 = 𝑇𝑃 and the temperature fluctuates close to the abiotic temperature while the population increases logarithmically.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This behaviour, increasing population with constant temperature, in- dicates that the TNM agents are optimising their mutual interactions, � 𝑗 𝐽𝑖 𝑗 𝑁 𝑗, as in the standard model, while keeping the temperature close to 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In (b) where 𝑇0 > 𝑇𝑃 we see that the population in- creases while the temperature decreases.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Thus the TNM agents are, on average, simultaneously optimising their mutual interactions while improving the temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In Arthur & Nicholson (2022) we discussed Selection by Survival (SBS) and Sequential Selection with memory (SSM).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' SBS is just dif- ferential survival i.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' at late times we see systems with Gaian features because those are the only ones that could survive that long.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' SBS is a good null model, here it would predict that the average temperature tends towards 𝑇𝑃 because runs that don’t maintain 𝑇𝑃 go extinct, leaving a small number of surviving runs that happen to operate at 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' SSM would predict that the punctuations during individual runs drive the average temperature towards 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The numbers in the top row of Figure 3 (a) and (b) show the proportion of runs which survive up to that point in the experiment.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In (b) for example, at 𝑇0 > 𝑇𝑃 about 9% of the runs have gone completely extinct (𝑁 = 0) by 105 generations compared to 3% when 𝑇0 = 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This is a relatively small increase in extinction rate compared to the relatively large decrease in the scaling factor 1/ � 1 + �𝑇0−𝑇𝑃 𝜏 �2� ≃ 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='14.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Figure 4 shows the model runs in more detail for 𝑇0 = 105 > 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (a), (b) and (c) demonstrate that the runs can be split into two types: low temperature, cooling core;' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' and high temperature, heating core.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We will loosely call these ‘Gaian’ and ‘non-Gaian’ respectively.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (d) is the crucial plot.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' It shows the proportion of surviving runs over time (dashed line) and the proportion of the surviving runs that have 𝑇 ≤ 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Here we see that while some runs do go extinct (SBS) in the surviving runs the proportion of Gaian states increases.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This means that non-Gaian states transition to Gaian states, leading to more of them over time.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This is exactly as sequential selection with memory predicts: (non-terminal) resets tend, on average, to improve conditions for life.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We will discuss the exact mechanism in detail below.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This mechanism, Sequential Selection with Memory (SSM) was discussed in Arthur & Nicholson (2022) and briefly in Secion 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Each model run consists of multiple quasi-equilibria interrupted by quakes (Figure 1).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' These quakes completely reset the species which make up the core.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' These core species are (by definition) the ones with large populations which control the model dynamics, in this case the total population and temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' As has been discussed in the TNM literature (especially Becker & Sibani (2014)), quakes occur spontaneously due to the evolution of a ‘parasite’ that disrupts the core.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' A parasite, 𝑎, is any species with significant reproduction probability that isn’t a member of the core.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' To have a large probability to reproduce, the sum of its interactions must be high enough that its reproduction rate is higher than its death rate.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Solving for fitness gives: ∑︁ 𝑗 𝐽𝑎 𝑗𝑛 𝑗 1 + �𝑇 −𝑇𝑃 𝜏 �2 ≥ 𝜇𝑁 + � 1 − 1 𝑝𝑘 � (9) Lower total population makes it easier for a parasite to occur by decreasing the 𝜇𝑁 term.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Low total population can occur either due to weak inter-species interactions in the core or unfavourable tem- peratures.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' However because of the smaller number of reproduction events at low 𝑁, fewer mutants are generated.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' On the other hand high populations raise the barrier and increase the number of mutation events.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Crossing the barrier requires finding a mutant 𝑎 with sufficiently large, positive interactions with some or all species in the core.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Large values of 𝐽𝑎 𝑗 are rare (for our choice of distribution, expo- nentially so) and the rate of generating new mutants is low.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Con- sidering each reproduction event as 𝐿 = 20 Bernoulli trials, the expected number of mutations in a reproduction is given by a Bino- mial distribution 𝐵(𝐿, 𝑝𝑚𝑢𝑡) with mean 𝐿𝑝𝑚𝑢𝑡 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='2 and variance 𝐿𝑝��𝑢𝑡 (1 − 𝑝𝑚𝑢𝑡) ≃ 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Thus the rate of exploration of the genetic space is quite slow.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Ultimately the barrier height is more important than the increased rate of reproduction and is what explains the trend of (slowly) increasing population and stability in the TNM.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' For much more on this see Becker & Sibani (2014).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Here we have to analyse how the temperature interacts with this mechanism.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Assume we have a case where 𝑇0 > 𝑇𝑃 as in Figure 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Temperatures far from 𝑇𝑃 make a quake more likely by reducing the total population and hence the barrier height.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' When a quake occurs a new core is selected on the basis of strong inter-species interactions that allow it to quickly ‘use up’ the carrying capacity.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This new core has an equal chance to be warming or cooling, because of the symmetry of 𝐻𝑖.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' If it is warming we stay in a non-Gaian state, if not we move to a Gaian state.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In a Gaian state the barrier can MNRAS 000, 1–18 (222) A Gaian Habitable Zone 5 Figure 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The column (a) shows the population (top row) and temperature (bottom row) where the background temperature is 𝑇0 = 𝑇𝑃 = 100.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Column (b) shows the population and temperature where 𝑇0 = 105.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The temperature in (a) is above 𝑇0 and 𝑇𝑃 while the temperature in (b) is below both 𝑇0 and 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' be significantly higher, leading to a much more stable, long lived core.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In a non-Gaian state the barrier is low, meaning the state will be relatively short lived, being vulnerable to parasites and to large population fluctuations which may result in total extinction.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' As shown in Figure 4 (d) over time this leads to more and more model runs in a Gaian state.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' To summarise: both mechanisms, SBS and SSM operate.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Ga- ian states have temperatures close to 𝑇𝑃, and thus high populations which, in this model, makes them more stable.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Non-Gaian states are far from 𝑇𝑃 and have low populations.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This makes them vulnerable to total extinction (SBS) and punctuation which can take a non-Gaian to a Gaian state (SSM).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In this model, for this particular temperature, SSM is a more important mechanism than SBS, though the ratio can vary with 𝑇0, as we will explore in the next section.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' These ideas can help explain why the Earth today is in a habit- able state.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Since its conception the Gaia hypothesis has been defined in numerous ways and ranging from a strong hypothesis that self- regulating feedback loops are an expected property of a life-planet coupled system,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' known as ‘probable Gaia’ Lenton & Wilkinson (2003),' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' to a weaker hypotheses that suggests that while the Earth MNRAS 000,' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 1–18 (222) (a) (b) 1400 1000 1200 800- 1000 800 600 N N 600- 400 400- 200 200 0 0 2000 4000 6000 8000 10000 0 2000 4000 6000 8000 10000 t (generations) t (generations) 108 To 108 Tp Tp 106 106 104 104 Temperature 102 102 100 100 98 98 - 96 96 94 94 0 2000 4000 6000 8000 10000 0 2000 4000 6000 8000 10000 t (generations) t (generations)6 Arthur & Nicholson Figure 2.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Model snapshot at 𝑡 = 9000 generations for the runs (a) and (b) from Figure 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Each node represents a different species, with the size of the node an indication of species’ population (upper and lower limits are applied to the point sizes for clarity).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The colour of the nodes indicates the heating or cooling effect, 𝐻𝑖.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The width of the arrows indicates the interaction strength 𝐽𝑖 𝑗𝑛𝑗.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Only interactions with core species are shown.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In (a) the red (bottom-right) core species has a strong enough heating effect to overwhelm the cooling effect of the other core species, so this configuration has a net heating effect, as seen in Figure 1(a).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In (b) both core species have a (weak) cooling effect, reducing the temperature, as seen in Figure 1(b).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' does have self-regulating feedback loops, these emerged merely by chance and that Gaia is not an expected feature of a planet hosting life, known as ‘lucky Gaia’ Watson (2004).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' As Figure 5 shows, in our model the fraction of Gaian states is increasing over time.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This sug- gests that for early life starting out on a planet, a large amount of luck might be needed to initially start off in a Gaian state, but for surviv- ing runs over time the probability of being in a Gaian state increases.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This would suggest that when observing a biosphere ‘lucky Gaia’ may be the case for young planets but ‘probable Gaia’ is operating for older ones.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The experiments in Figure 5 have considered systems with only internal perturbations, that is, those generated by the biosphere.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' How- ever, real planets experience many abiotic perturbations, both rapid and slower, such as changes in volcanic activity, changes in solar luminosity or impacts by large objects Covey et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (1994);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Overpeck & Cole (2006);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Goldblatt & Zahnle (2011).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Life is thought to have emerged early on Earth during a time when debris left over from the formation of the solar system was frequently colliding with the Earth.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Biospheres in a non-Gaian state will be more susceptible than Gaian biospheres to perturbations and will have a higher risk of going extinct.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This is closely related to the ‘Gaian bottleneck’ hypothesis Chopra & Lineweaver (2016) that proposes that early on in a planet’s history, if life emerges it must quickly establish self-regulatory feed- back loops to stabilise the climate of its planet in order to persist.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' If the biosphere fails then life goes extinct, the planet’s abiotic pro- cesses take over and the planet reverts to an inhospitable state.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' What is novel here is the idea that apart from total extinction, a planet can have a ‘near death experience’ where a mass extinction clears out a large fraction of the extant species.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' These mass extinctions are cru- cial for the exploration of the space of possible ecosystems Arthur & Sibani (2017) and ultimately lead to the emergence of long-lived stable states.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Population diversity is known to significantly increase the resilience of ecosystems to perturbations Peterson et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (1998);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Luck et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2003), and additionally yeast Guan et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2012) and bacteria Lambert & Kussell (2014) have been shown to develop in- creased resilience to environmental stressors if exposed to them in the past.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' It is possible that large perturbations that do not eliminate all life are actually beneficial for evolving Gaia.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Indeed, there may be evidence of this in Earth history, as it is thought that a period of global glaciation may have triggered the evolution of multi-cellular life Hoffman et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (1998);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Hedges (2004);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Vincent et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2004);' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Boyle et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2007).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 4 HABITABLE ZONE EXPERIMENTS The habitable zone around a star is defined as the distance from a star where liquid water could exist on the surface of a planet Kasting et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (1993).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Models demonstrate that the habitable zone is impacted by several factors, including the age and class of the host star Ramirez & Kaltenegger (2016), planetary mass Kopparapu et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2014), plane- tary atmospheric composition Pierrehumbert & Gaidos (2011), and the surface water content of the planet Abe et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2011).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Additionally a planet being within the habitable zone doesn’t guarantee habitabil- ity, as a planet may have more than one possible climate state for the same stellar and orbital parameters, e.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='g.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' a temperate Earth versus a frozen Earth Goldblatt & Zahnle (2011).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' For a more extreme ex- ample, it is thought that Venus and Earth might represent alternate end states for the same planetary system, with small perturbations occurring early on in their history influencing their modern day states Lenardic et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2016).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Existing exoplanet surveys and models have identified that rocky MNRAS 000, 1–18 (222) (a) (b) 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='04 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='02 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='00 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='02 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='04A Gaian Habitable Zone 7 Figure 3.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (a) shows the average (over all surviving model runs) of the population (top row) and temperature (bottom row) where the background temperature 𝑇0 = 100 = 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Column (b) shows the population and temperature where 𝑇0 = 105.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The numbers next to the vertical dashed lines in the top row are the proportion of runs which have survived for that number of generations.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' planets can exist at a range of distances from their host star Domagal- Goldman et al.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (2016).' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Thus, it is a natural question to ask about the stability and persistence of Gaia across a range of background tem- peratures, some more conducive to life, some less.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In this section we run many experiments where we vary the background temperature 𝑇0 and look at averages over 1000 model histories.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' To mimic the idea of a habitable zone with and without biotic influence we com- pare two versions of the model: one where life cannot influence the temperature, 𝜎𝐻 = 0, and one where life can influence it 𝜎𝐻 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='05.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' In Figure 5 we show the fraction of runs which survive for 105 generations in both scenarios.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Perhaps surprisingly, the distributions are roughly similar.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' As the background temperature changes, a similar number of model runs survive for 105 generations whether life can effect the environment or not.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' This shows, at least, that species- environment interactions have little effect on the probability of total extinction and therefore on the presence or absence of life.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' However, as we saw in the previous section, the model runs can be split into Gaian and non-Gaian states.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Figure 5 also shows the proportion of MNRAS 000, 1–18 (222) (a) (b) 400 400 350- 350 10.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='972 i0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='909 300 - 300- 10.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='98 10.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='989 ≥ 250 ≥ 250 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='9 i0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='992 10.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='981 200 - 10.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='99 150 - 150- 100 100 102 103 104 105 102 103 104 105 t (generations) t (generations) 108 108 Tp Tp T 106 106 Temperature 104 - Temperature 104 102 102 100 100 98 98 102 103 104 105 102 103 104 105 t (generations) t (generations)8 Arthur & Nicholson Figure 4.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' 𝑇0 = 105.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (a) shows the temperature at 𝑡 = 105 generations versus population.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Colour corresponds to the heating (red) or cooling (blue) effect of the core.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' There are clearly two distinct clusters: one with (potentially) high population and low temperature and one with low population and high temperature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (b) and (c) show histograms of the temperature and population respectively.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' (d) shows the proportion of surviving runs at each generation as well as the proportion that have 𝑇 ≤ 𝑇𝑃.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' runs that have 𝑁 > 200.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' The value of 200 is not itself significant, what is important is the comparison between 𝜎𝐻 = 0 and 𝜎𝐻 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='05.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Far from 𝑇𝑃, only the Gaian states can have large populations, in the other cases the total population is low and life is simply ‘clinging on’.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Importantly for exoplanet astronomy, a small pocket of life that is clinging on to existence is unlikely to produce a detectable bio- signature.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' Figure 6 shows the population of the model runs as a function of 𝑇0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We see that when 𝜎𝐻 = 0 the total population at 𝑇𝑃 is larger.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' At 𝜎𝐻 = 0 the TNM agents are only attempting to optimise inter- species interactions, not interactions and temperature and thus can find a better maxima.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' For example, strongly symbiotic cores may have a detrimental effect on the temperature which is only relevant in the 𝜎𝐻 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='05 case.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' However, the population falls rather rapidly with 𝑇0 at 𝜎𝐻 = 0 compared to the 𝜎𝐻 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='05 case.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content=' We also see (from the colour gradient) that at 𝜎𝐻 = 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='05, for 𝑇0 far from 𝑇𝑃 only MNRAS 000, 1–18 (222) (a) (b) 110.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0 110.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0 107.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='5 107.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='5 105.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0 105.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0 102.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='5 102.' metadata={'source': 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metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='125 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='150 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='175 N P(T) (c) (d) 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0000 1.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0005 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0010 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='8 - 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0015 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='6 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0020 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0025 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='4 - 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0030 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='2 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0035 Fraction Surviving 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0040 0.' metadata={'source': '/home/zjlab/wf/langchain-ChatGLM/knowledge_base/49A0T4oBgHgl3EQfNv86/content/2301.02150v1.pdf'} +page_content='0 Fractionofsurvivors