Describes the unicellular microorganisms of three billion years ago. Explains how these primitive cells gave rise to biochemical systems and the present oxygen-rich atmosphere. Numerous diagrams, charts, and illustrations. (MA)

Discusses the coevaluation of species within ecosystems. This process gives rise to interesting patterns in the total number of species found in a given area, in their relative abundances, and in the overall structure of the local food web. (Author/MA)

Discusses the relationship of adaptation to natural selection. Since natural selection does not always lead to adaptation, defining adaptation is sometimes a difficult task. (MA)