document: The simulated emergence of distributed environmental control in evolving microcosms This work continues investigation into Gaia theory -LRB- Lovelock , The ages of Gaia , Oxford University Press , 1995 -RRB- from an artificial life perspective -LRB- Downing , Proceedings of the 7th International Conference on Artificial Life , p. 90-99 , MIT Press , 2000 -RRB- , with the aim of assessing the general compatibility of emergent distributed environmental control with conventional natural selection . Our earlier system , GUILD -LRB- Downing and Zvirinsky , Artificial Life , 5 , p.291-318 , 1999 -RRB- , displayed emergent regulation of the chemical environment by a population of metabolizing agents , but the chemical model underlying those results was trivial , essentially admitting all possible reactions at a single energy cost . The new model , METAMIC , utilizes abstract chemistries that are both -LRB- a -RRB- constrained to a small set of legal reactions , and -LRB- b -RRB- grounded in basic fundamental relationships between energy , entropy , and biomass synthesis/breakdown . To explore the general phenomena of emergent homeostasis , we generate 100 different chemistries and use each as the basis for several METAMIC runs , as part of a Gaia hunt . This search discovers 20 chemistries that support microbial populations capable of regulating a physical environmental factor within their growth-optimal range , despite the extra metabolic cost . Case studies from the Gaia hunt illustrate a few simple mechanisms by which real biota might exploit the underlying chemistry to achieve some control over their physical environment . Although these results shed little light on the question of Gaia on Earth , they support the possibility of emergent environmental control at the microcosmic level
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