The Cambrian Period records one of the most extraordinary transitions in the history of life. Although animals may have first appeared nearly 700 million years ago, with the earliest sponges, their initial diversifications appear to have been modest until a richly diverse fossil fauna appeared abruptly about 170 million years later. In The Cambrian Explosion, Erwin and Valentine synthesize research from many fields to explain why there was such remarkable novelty of animal forms.

Patterns of evolution, as illustrated by the fossil record

Phylogenetic analysis and morphometrics have been developed by biologists into rigorous analytic tools for testing hypotheses about the relationships between groups of species. This book applies these tools to paleontological data. The fossil record is our one true chronicle of the history of life, preserving a set of macroevolutionary patterns; thus various hypotheses about evolutionary processes can be tested in the fossil record using phylogentic analysis and morphometrics. The first book of its type, Fossils, Phylogeny, and Form will be useful in evolutionary biology, paleontology, systematics, evolutionary development, theoretical biology, biogeography, and zoology. It will also provide a practical, researcher-friendly gateway into computer-based phylogenetics and morphometrics.

An expanded and updated second edition comprehensively looks at macroevolution, integrating evolutionary processes at all levels to explain animal diversity.