Centers of origin and related concepts. Syst. Zool. 23:265–287.—The concept of center of origin in the Darwinian sense is often accepted and used as if it were a conceptual model necessary and fundamental to historical zoogeographical analysis. But in certain respects it is inconsistent with the principles of common ancestry and vicariance2 (e.g., allopatric speciation), and its application to concrete examples of animal distribution generally yields ambiguous results. In the following pages we present a critique of the concept of center of origin, and outline an alternative conceptual model, involving generalized patterns of biotic distribution (generalized tracks). We assume that a given generalized track estimates an ancestral biota that, because of changing geography, has become subdivided into descendant biotas in localized areas. We assume that in such areas, more or less biotically isolated from one another by barriers to dispersal, the descendant biotas differentiate and produce more modern patterns of taxonomic diversity and distribution. We reject the Darwinian concept of center of origin and its corollary, dispersal of species, as a conceptual model of general applicability in historical biogeography. We admit the reality of dispersal and specify how examples of dispersal may be recognized with reference both to sympatry and to generalized tracks, but we suggest that on a global basis the general features of modern biotic distribution have been determined by subdivision of ancestral biotas in response to changing geography.