Mammals as a Key to Evolutionary Theory

Mammalogy provides exceptionally fertile grounds for advancing evolutionary theory, because its data base spans from diverse researches on living forms to a rich fossil record. I illustrate this by integrating interdisciplinary evidence and hypotheses in the habitat theory, including: 1) the context of paleoclimatic changes, and how species' distributions responded to them; 2) geographical biases in turnover rates of species; 3) the turnover-pulse hypothesis; 4) breadth of resource use as a cause of phylogenetic turnover rates. Preliminary tests using the late Neogene records of the Americas and Africa suggest that major aspects of the Great American Interchange have parallels in the African record, as predicted by the habitat theory. Comparable forces may have operated in both cases. The habitat theory of the Great American Interchange differs from the traditional emphasis on the effects of interspecific competition.