ABSTRACT
Life in its most basic form occurs in four bands around the Earth. Of the four bands, we are most familiar with the second band that forms the surface biosphere and includes virtually all plants and animals as well as many of the bacterial communities that humans perceive to be important, However, the bacterial communities dominate the other bands of life-often virtually unseen and mostly unrecognized. The four bands of life are easily defined from the outermost to the innermost by their positions relative to the solid or liquid surfaces of the planet, whether in mountains, soils, or deep under the oceans.
