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 the evolution of biological diversity. In seeking to unravel the patterns and processes that regulate large-scale evolutionary change, the study of macroevolution asks: What regulates biological diversity and its historical development ? Can it be explained by natural selection alone ? Has geologic history regulated the tempo of diversification ? The answers to such questions lie in many disciplines including genetics palaeontology and geology. This expanded and updated second edition offers a comprehensive look at macroevolution and its underpinnings, with a primary emphasis on animal evolution. From a neo-Darwinian point of view, it integrates evolution 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. This book also takes a hard look at the Cambrian explosion. This new edition possesses all of the comprehensiveness of the first edition, yet ushers it into the age of molecular approaches to evolution and development. It also integrates important recent contribution, made to our understanding of the early evolution of animal life. Researcher, and graduate students will find this insightful book a most comprehensive and up to date examination of macroevolution.