Origination, Evolutionary Radiation, and Extinction in the Modern World: The Story of Partulid Tree Snails

Abstract

Charles Darwin's (1859) case for the fact of evolution was as crucial to his theory as was the mechanism he proposed. The idea of natural selection becomes interesting and compelling only in the context of all the great facts of natural history that it explains. Life on earth has changed. New forms have appeared, replacing forms that have ceased to exist. Origination and extinction are two of the great facts of natural history. They underlie the patterning of biological diversity. Case by case, these facts are explained more consistently, more simply, and more compellingly by the mechanisms of evolution than by any set of ad hoc explanations.