The voice of historical biogeography

Historical biogeography is going through an extraordinary revolution concer ning its foundations, basic concepts, methods, and relationships to other d isciplines of comparative biology. There are external and internal forces t hat are shaping the present of historical biogeography. The external forces are: global tectonics as the dominant paradigm in geosciences, cladistics as the basic language of comparative biology and the biologist's perception of biogeography. The internal forces are: the proliferation of competing a rticulations, recourse to philosophy and the debate over fundamentals. The importance of the geographical dimension of life's diversity to any underst anding of the history of life on earth is emphasized. Three different kinds of processes that modify the geographical spatial arrangement of the organ isms are identified: extinction, dispersal and vicariance. Reconstructing p ast biogeographic events can be done from three different perspectives: (1) the distribution of individual groups (taxon biogeography) (2) areas of en demism (area biogeography), and (3) biotas (spatial homology). There are at least nine basic historical biogeographic approaches: centre of origin and dispersal, panbiogeography, phylogenetic biogeography, cladistic biogeogra phy, phylogeography, parsimony analysis of endemicity, event-based methods, ancestral areas, and experimental biogeography. These nine approaches cont ain at least 30 techniques (23 of them have been proposed in the last 14 ye ars). The whole practice and philosophy of biogeography depend upon the dev elopment of a coherent and comprehensive conceptual framework for handling the distribution of organisms and events in space.