Explanation

Adaptive radiation. Examples of adaptive radiation are (i) Darwin’s Finches of Galapagos Island They had common ancestors but different types of modified beaks according to their food habits. Darwin differentiated thirteen species of the finches according to their food habits (ii) Australian Marsupials Darwin explained that adaption radiation gave rise to the varieties of marsupials (pouched mammals) in Australia by the same process of adaptive radiation as found in the finches of Galapagos Islands. (iii) Placental mammals in Australia exhibit adaptive radiation in evolving into varieties of placental mammals each of which appears to be similar to corresponding marsupials