Chapter 14 Tetrapod Mass Extinctions — A Model of the Regulation of Speciation Rates and Immigration by Cycles of Topographic Diversity

Abstract

The description of mass extinctions, one of the unique gifts of palaeontology to evolutionary and ecological theory, is a rich source of opportunities for generating and testing hypotheses about the regulation of speciation, faunal diversification, and the fate of clades. The two best-known mass extinctions are those at the Permian–Triassic boundary and at the Cretaceous–Tertiary boundary. For terrestrial vertebrates, the most discussed extinctions are those at the end of the Pleistocene and at the Cretaceous–Tertiary boundary. Most proposed explanations are ad hoc—search is made for a climatic or other environmental change during the extinction event, and when evidence for such change is found, the change itself is indicted as the agent, which directly or indirectly caused the extinctions. Community composition patterns are thus drawn for the Early Permian of North America, the Late Permian and Triassic of South Africa, and the Early Cretaceous and Late Jurassic of North America.