The factors that influenced the evolution of the vertebrates are compared with the importance of variation and selection that Darwin emphasised in this broad study of the patterns and forces of evolutionary change.

The Evolution of Phylogenetic Systematics aims to make sense of the rise of phylogenetic systematics—its methods, its objects of study, and its theoretical foundations—with contributions from historians, philosophers, and biologists. This volume articulates an intellectual agenda for the study of systematics and taxonomy in a way that connects classification with larger historical themes in the biological sciences, including morphology, experimental and observational approaches, evolution, biogeography, debates over form and function, character transformation, development, and biodiversity. It aims to provide frameworks for answering the question: how did systematics become phylogenetic?

The roots of this book and its sister volume, Mammal Phylogeny: Placentals, go back to discussions and plans, shelved for a while, between F. S. Szalay and W. P. Luckett during the international and multidisciplinary symposium on rodent evolution sponsored by NATO, July 2-6, 1984, in Paris. That conference, orga nized by W. P. Luckett and J. -L. Hartenberger, the proceedings of which were published in 1985, proved an inspiring experience to all of the participants, as this was repeatedly expressed both during and after the meetings. In addition to issues relating to rodents, general theoretical topics pertaining to the evolutionary biol ogy and systematics of other groups of mammals regularly surfaced during the presentations and discussions. M. J. Novacek, who was also a participant in the rodent symposium, shared with Luckett and Szalay the enthusiasm acquired there, and he also expressed strong interest for a meeting on mammal evolution with a general focus similar to that of the rodent gathering. In 1988, Szalay and Luckett, after having planned in detail a program, direc tion, and core list of participants, were awarded a $30,000 grant by the Alfred P. Sloan Foundation through the Research Foundation of the City University of New York. The grant was contingent upon obtaining additional funds sufficient to assure that the symposium would be held. Raising the remaining funds proved to be a problem.

A world of categones devmd of spirit waits for life to return. Saul Bellow, Humboldt's Gift The stock-in-trade of communicating hypotheses about the historical path of evolution is a graphical representation called a phylogenetic tree. In most such graphics, pairs of branches diverge from other branches, successively marching across abstract time toward the present. To each branch is tied a tag with a name, a binominal symbol that functions as does the name given to an individual human being. On phylogenetic trees the names symbolize species. What exactly do these names signify? What kind of information is communicated when we claim to have knowledge of the following types? "Tetonius mathewzi was ancestral to Pseudotetonius ambiguus. " "The sample of fossils attributed to Homo habzlis is too variable to contain only one species. " "Interbreeding populations of savanna baboons all belong to Papio anubis. " "Hylobates lar and H. pileatus interbreed in zones of geographic overlap. " While there is nearly universal agreement that the notion of the speczes is fundamental to our understanding of how evolution works, there is a very wide range of opinion on the conceptual content and meaning of such particular statements regarding species. This is because, oddly enough, evolutionary biolo gists are quite far from agreement on what a species is, how it attains this status, and what role it plays in evolution over the long term.

Representing the state of the art in evolutionary paleobiology, this book provides a much-needed overview of this rapidly changing field. An influx of ideas and techniques both from other areas of biology and from within paleobiology itself have resulted in numerous recent advances, including increased recognition of the relationships between ecological and evolutionary theory, renewed vigor in the study of ecological communities over geologic timescales, increased understanding of biogeographical patterns, and new mathematical approaches to studying the form and structure of plants and animals. Contributors to this volume—a veritable who's who of eminent researchers—present the results of original research and new theoretical developments, and provide directions for future studies. Individually wide ranging, these papers all share a debt to the work of James W. Valentine, one of the founders of modern evolutionary paleobiology. This volume's unified approach to the study of life on earth will be a major contribution to paleobiology, evolution, and ecology.