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The Gaia hypothesis, also known as Gaia theory or Gaia principle, proposes that organisms interact with their inorganic surroundings on Earth to form a self-regulating, complex system that helps to maintain the conditions for life on the planet. Topics of interest include how the biosphere and the evolution of life forms affect the stability of global temperature, ocean salinity, oxygen in the atmosphere and other environmental variables that affect the habitability of Earth. The hypothesis was formulated by the chemist James Lovelock and co-developed by the microbiologist Lynn Margulis in the 1970s. The hypothesis was initially criticized for being teleological and contradicting principles of natural selection, but later refinements resulted in ideas framed by the Gaia hypothesis being used in fields such as Earth system science, biogeochemistry, systems ecology, and the emerging subject of geophysiology.〔〔Gribbin, John (1990), "Hothouse earth: The greenhouse effect and Gaia" (Wiedenfield and Nicholson)〕 Nevertheless, the Gaia hypothesis continues to attract criticism, and today some scientists consider it to be only weakly supported by, or at odds with, the available evidence. In 2006, the Geological Society of London awarded Lovelock the Wollaston Medal in part for his work on the Gaia hypothesis.〔(【引用サイトリンク】url=https://www.geolsoc.org.uk/About/History/Awards-Citations-Replies-2001-Onwards/2006-Awards-Citations-Replies )〕 ==Introduction== Gaian hypotheses suggest that organisms co-evolve with their environment: that is, they "influence their abiotic environment, and that environment in turn influences the biota by Darwinian process". Lovelock (1995) gave evidence of this in his second book, showing the evolution from the world of the early thermo-acido-philic and methanogenic bacteria towards the oxygen-enriched atmosphere today that supports more complex life. A reduced version of the hypothesis has been called "influential Gaia", which states the biota influence certain aspects of the abiotic world, e.g. temperature and atmosphere. It states the evolution of life and its environment may affect each other. An example is how the activity of photosynthetic bacteria during Precambrian times have completely modified the Earth atmosphere to turn it aerobic, and as such supporting evolution of life (in particular eukaryotic life). Biologists and Earth scientists usually view the factors that stabilize the characteristics of a period as an undirected emergent property or entelechy of the system; as each individual species pursues its own self-interest, for example, their combined actions may have counterbalancing effects on environmental change. Opponents of this view sometimes reference examples of events that resulted in dramatic change rather than stable equilibrium, such as the conversion of the Earth's atmosphere from a reducing environment to an oxygen-rich one. Less accepted versions of the hypothesis claim that changes in the biosphere are brought about through the coordination of living organisms and maintain those conditions through homeostasis. In some versions of Gaia philosophy, all lifeforms are considered part of one single living planetary being called ''Gaia''. In this view, the atmosphere, the seas and the terrestrial crust would be results of interventions carried out by Gaia through the coevolving diversity of living organisms. However, the Earth as a unit does not match one of the generally accepted biological criteria for life: there is no evidence to suggest that "Gaia" has reproduced yet. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gaia hypothesis」の詳細全文を読む スポンサード リンク
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