The Gaia Hypothesis really. Not actually a theory. A theory explains facts, is testable, can be used to make accurate predictions. A hypothesis is more of a speculation, an educated guess, a sort of "what-if" kind of daydream, possibly based on facts. A thought nudge.
Gaia's real home was in ancient Greek mythology, where she was a big player. Her name meant "land" or "earth" (hint, hint), and she was said to be the ancestral mother of all life. Gave birth to lots of things, some pleasant and some not, and so on, as if you couldn't guess.
Anyhoo, the Gaia Theory-Hypothesis was proposed by Lynn Margulis (chemist) and James Lovelock (microbiologist), who speculated that the earth might be a self-regulating system, that all living organisms plus all inorganic material on the planet are part of one dynamic whole, a meta-organism that self-regulates and maintains conditions which support all life.
So it's probably a good idea to stay on its good side if you want to keep breathing. Just saying.
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Me? Thinking of becoming a god. Might be fun for a while.