Ecology shows that living beings, with all their diversity, make up a homogenous system on the earth's surface, with rules that are no less exacting than those applicable to gravitational astronomy (celestial mechanics). The physical energy coming from the sun in the form of radiation is attracted by green plant-life, be it vegetation growing on the land or microscopic algae floating on the surface of the ocean; this energy is then transformed into chemical energy, with, incidentally, a modest yield, due (...) to the process of chlorophyllian synthesis. This stage is the only one to include a productive process—an anabolism. Other sorts of living beings derive their energy and the elements necessary for their sustenance and multiplication from organic matter devised in this way. Some vegetarian animals feed on them and are in their turn prey to predators which are themselves devoured by other predators. Food chains, grouped in bunches or network systems, are thus established on the principle of a complex pyramid. Each consumer occupies a place at a trophic level, which is clearly defined, where he guarantees the conveyance of matter and energy which are degraded in accordance with the laws of thermodynamics. These biological mechanisms entail numerous species, ranging from the most elementary forms of life to birds and mammals. Decomposition agents then recycle the mineral elements and make them available to plants. In any given area, the inert chemical elements and the community of living beings (embracing all species) together constitute a biological entity or ecosystem, this is a kind of supraspecific organism which functions with a certain flexibility, and yet is ordered down to the last detail. Just as a man consists of a heart, lungs, a liver, so a natural community consists of “organs” which are each made up of one of the various constituent species. These ecosystems are the fundamental units of the living world and they are relatively independent of one another, although exchanges do occur between them. They all come together to form a balanced system which encompasses the whole complex of living beings. This is the biosphere, a gigantic mechanism with innumerable cogs and gears which have evolved in harmony with each other throughout the whole of history, going as far back as the first trace of life on earth. (shrink)