When a new species form by geographic isolation, it is called geographical speciation or allopatric speciation. Geographical isolation is a physical separation which prevents gene flow between distinct populations. The populations on three land masses from this example, will eventually diverge from individuals of the single species that migrated to those land masses. The members of the populations, which once belonged to the same species, will no longer be able to mate and produce offspring. Eventually, the formation of new species will occur, in this example three new species on three land masses from the ancestral Adansonia species.
