On the natural selection and evolution of the aerobic phototrophic bacteria.

This contribution gives a brief survey of the short history since the discovery of the aerobic phototrophic bacteria to focus on a general evolutionary scenario. Most of the citations are of reviews that have covered the earlier literature and to which the reader is directed at appropriate places in the following text. The data summarized in these reviews are supplemented with information from recent or otherwise key primary publications in order to support a synthesis that addresses vexing questions about bacteria containing photosynthetic pigment-protein complexes, but which are incapable of growth with light as the sole, or even the major source of energy.