2Linking Evolutionary Pattern and Process The Relevance of Species Concepts for the Study of Speciation

Species are fundamental units of natural diversity--of obvious interest to systematists, evolutionary biologists, ecologists, and conservation biologists. However, both within and among these disciplines, there is considerable disagreement about the way in which species should be defined. As a result, the last two decades have witnessed a proliferation of new species concepts and a rapidly expanding literature, in which the merits of the various definitions are vigorously debated. Much of the debate has been carried out within the community of systematic biologists, who see the definition of species as the prov-ince of their discipline. The emergence of phylogenetic systematics resulted in profound unhappiness with the Biological Species Concept (BSC), which until recently remained the default framework for thinking about spe