NCERT · Class 12 · Biology · EvolutionWhat is Adaptive Radiation? Explain this process with two classic biological examples.

Adaptive Radiation

Adaptive radiation is an evolutionary process in which a single ancestral species rapidly evolves into a variety of different species, each possessing structural and behavioral adaptations that allow them to occupy diverse ecological niches.

Classic Examples:

1. Darwin’s Finches:

   • On the Galápagos Islands, Charles Darwin observed various species of finches that evolved from a common ancestral seed-eating finch from mainland South America.
   • Over time, to utilize different available food sources on different islands, finches developed diverse beak shapes and sizes specialized for eating insects, seeds, fruits, and cacti.

2. Australian Marsupials:

   • Within the isolated Australian continent, a single ancestral marsupial underwent adaptive radiation to give rise to a wide variety of marsupial species.
   • These species evolved to fill distinct ecological roles, such as the marsupial mole (burrowing), Tasmanian wolf (carnivorous), koala (arboreal), and kangaroo (herbivorous leaping).