Biogeography is the science which deals with questions of the distribution of species usually at regional to continental scales. The patterns of species distribution at this level can usually be explained through a combination of historical factors in combination with the area and isolation of landmasses, in combination with the available energy supply.
Prior to the publication of The Theory of Island Biogeography by Robert MacArthur and E.O. Wilson in 1967 (which expanded their 1963 paper on the same topic) the field of biogeography was seen as a primarily historical one, and as such the field was seen as a purely descriptive one. MacArthur and Wilson changed this perception, and showed that the species richness of an area could be predicted in terms of such factors as habitat area, immigration rate and extinction rate. This gave rise to an interest in island biogeography. The application of island biogeography theory to habitat fragments spurred the development of the fields of conservation biology and landscape ecology (at least among British and American academics; landscape ecology has a distinct genesis among European academics).
Classic biogeography has been given a boost through the development of molecular systematics. This development allowed scientists to test theories about the origin and dispersal of populations (e.g., island endemics). For example, while classic biogeographers were able to speculate about the origins of species in the Hawaiian Islands, molecular systematics allows them to test theories of relatedness between these populations and putative source populations in Asia and North America.
Biogeography is a synthetic science, related to geography, biology, geology, climatology, and ecology.
Some fundamentals in biogeography are
- evolution (change in genetic composition of a population)
- extinction (disappearance of a species)
- dispersal (movement of populations away from their point of origin)