An hypothesis proposed during the early 1970s by James Lovelock which states that all living organisms have the ability to affect their surroundings such as the atmosphere, lithosphere, and climate to maximize its biological success. The hypothesis connects the evolution and survival of a species to the evolution and conditions of its environment. [Scientists on Gaia; Stephen Schneider et al; MIT Press; Cambridge, Mass.; pages 4-7, 62; 1991.] [Atmospheric Change; Graedel, T. E.; W. H. Freeman and Company; New York; page 418-421; 1993.]

This definition is in context to Atmospheric Chemistry. See more contextual defintions for Gaia Hypothesis.