Allopatric speciation is said to occur when two groups of organisms are separated by a physical or geographical barrier. Examples of such barriers are ocean, mountain range, rivers, etc. A good example of allopatric speciation is Galapagos finch. Different species of this bird can be found in different islands at Galapos, which is located at Pacific Ocean off South America. The ocean is barrier that isolate the species from one another.
