Adaptive radiation: This process of evolution of different species in a given geographical area starting from a point and literally radiating to other areas of geography (habitats) is called adaptive radiation. It is an example of biogeographic evidence.

1) During his journey Darwin went to Galapagos Islands. There he observed an amazing diversity of creatures, small black birds (Darwin’s Finches).  

2) He realised that there were many varieties of finches in the same island, from the original seed-eating  to  insectivorous and vegetarian finches .

3) Darwin’s finches represent one of the best examples of this phenomenon.

4) Another example is Australian marsupials. A number of marsupials, each different from the other  evolved from an ancestral stock, but all within the Australian island continent. When more than one adaptive radiation appeared to have occurred in an isolated geographical area, this is called convergent evolution.