Biogeography

We have referred to pattern and process throughout different sections of this course. These concepts are central to the study of biogeography which, in turn, incorporates many of the topics in evolutionary biology. Biogeography often leads us to infer process from pattern.
Biogeography is the study of the distributions of organisms in space and time. It can be studied with a focus on ecological factors that shape the distribution of organisms, or with a focus on the historical factors that have shaped the current distributions. Certain regions of the world have "Mediterranean climates" where ocean current and wind patterns hit the west coast of N and S continents (Medit. region, California coast, Chile coast, SW Africa coast). Similar climate has lead to convergent , but unrelated (by definition) types of plants. To make sense of these types of ecological patterns we require a phylogenetic (historical) perspective: we need to focus on monophyletic groups.
The importance of a geographic scale was certainly appreciated by Darwin: the Galapagos finches were morphologically distinct and geographically distinct and there must be a connection. Moreover, the general view that speciation is a central phenomenon in evolution, and that most speciation is allopatric speciation assumes that geography plays a central role: some
If different taxa all have similar area cladograms (i.e., are "congruent"), then the sequence of vicariance events is supported. If one taxon is represented in a region where none of the other taxa are found, then one might be forced to invoke dispersal to account for the disjunct distribution. The strength of this approach is that hypotheses are testable and one need not resort to ad hoc explanations that should be taken on faith. Biogeography can be practiced in a scientific manner despite its historical