Question

What is adaptive radiation? Explain it with reference to Australian marsupials. Can this fauna indicate its parallel evolution with placental mammals? How do you explain their geographic distribution?

Answer 1

Adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches. This can be observed These are other examples of adaptive radiation. A number of marsupials (pouched mammals) each evolved differently from an ancestral stock but all within the Australian continent.

These marsupials evolve with the placental mammals. Close to 70% of the 334 extant species occur on the Australian continent (the mainland, Tasmania, New Guinea, and nearby islands). The remaining 100 are found in the Americas — primarily in South America, but thirteen in Central America, and one in North America, north of Mexico.