Biogeography
Both Darwin and Wallace gave a great deal of attention to oceanic islands as offering examples of evolution, especially speciation. Darwin visited the Galapagos Islands and studied its fauna. Wallace spent years on the islands of S.E. Asia. This interest was revived by The theory of island biogeography by Robert MacArthur and E.O. Wilson in 1967. They showed that the variation in species in a single area could be predicted if one knew the habitat area, immigration rate, and extinction rate.