In the Gaia theory air, water, and soil are major components of one central organism, planet Earth. What we typically think of as life - the plants and animals that inhabit the earth - has evolved merely to regulate the chemistry of the biosphere. Humans are insignificant participants, far less important to the life cycle than termites. Even the imbalance that we have created by adding massive quantities of carbon dioxide to the atmosphere may be brought back to acceptable levels by other organisms functioning in their capacity to correct excesses.