Dr. James Lovelock roposed the GAIA concept. Few ideas have
ignited more contentious debate within the modern scientific
community than James Lovelock's Gaia hypothesis -- the proposal
that the Earth can be viewed as a superorganism with the
capacity to regulate its internal environment. Lovelock, an
atmospheric chemist employed in the 1960s by NASA, first
proposed the Gaia concept to account for the anomalous
composition of Earth's atmosphere relative to those of
neighboring Mars and Venus. The peculiar mix of gases that
envelope Earth and support life on the planet, Lovelock argues,
is created and maintained by Life itself. The composition of the
atmosphere, in turn, profoundly affects Earth's climate, which
has remained favorable for life for at least 3.5 billion years.
Lovelock's thesis, then, is that organisms have collectively
acted throughout the history of the planet to make the global
environment hospitable for the biosphere as a whole.