An engaging area of biology for more than a century, the study of macroevolution continues to offer profound insight into our understanding of the tempo of evolution and of the evolution of biological diversity. What regulates biological diversity and its historical development? Can it be explained by natural selection alone? Has geologic history regulated the tempo of diversification? This expanded and updated second edition offers a comprehensive look at macroevolution and its underpinnings, with a primary emphasis on animal evolution. From a Neodarwinian point of view, it integrates evolutionary processes at all levels to explain the diversity of animal life. It examines a wide range of topics including genetics and speciation, development and evolution, the constructional and functional aspects of form, fossil lineages, and systematics, and it takes a hard look at the Cambrian explosion. It delves into the age of molecular science, and integrates important recent contributions made to our understanding of evolution. Researchers and graduate students will find this insightful book a most comprehensive and up-to-date examination of macroevolution.