weak Gaia is self organizing , which works to keep it's systems in meta-equilibrium-conducive to life from early life that was thermo-acidic-phyllic and methangenic to current Oxygen that supports more complex life and has resisted runaway positive feedback -like what happened on Mars or Venus vs strong Gaia basically single organism 'cognitive transformation of biospherenoosphere<self reflective>biosphere gaia theory and daisyworld simulation The scientifically accepted form of the hypothesis has been called "influential Gaia". It states that biota minimally influence certain aspects of the abiotic world, e.g. temperature and atmosphere. They state 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). The Gaia theory posits that the Earth is a self-regulating complex system involving the biosphere, the atmosphere, the hydrospheres and the pedosphere, tightly coupled as an evolving system. The theory sustains that this system as a whole, called Gaia, seeks a physical and chemical environment optimal for contemporary life. Gaia evolves through a cybernetic feedback system operated unconsciously by the biota, leading to broad stabilization of the conditions of habitability in a full homeostasis. Many processes in the Earth's surface essential for the conditions of life depend on the interaction of living forms, especially microorganisms, with inorganic elements. These processes establish a global control system that regulates Earth's surface temperature, atmosphere composition and ocean salinity, powered by the global thermodynamic disequilibrium state of the Earth system. "Gaia is just symbiosis as seen from space".An analogous alternative geophysiology which views the Earth as a single cell was developed by Lewis Thomas in his The Lives of a Cell: Notes of a Biology Watcher (1974).