Adaptive Radiation - Practice Questions & MCQ

• The process of evolution of different species starting from a point in a geographical area and finally radiating to other areas of geography is called adaptive radiation.
• It involves the development of different functional structures from a common ancestral form.
• The presence of homologous organs are evident of adaptive radiation.

Examples of Adaptive Radiation:

1. Darwin’s Finches:

• Darwin observed an amazing diversity of Finches in the Galapagos Islands.
• Of all the varieties of finches, which were observed on the same island, he found that all of them had evolved from original seed-eating finches.
• He explained that after originating from a common ancestral seed-eating stock, the finches must have radiated to different geographical areas and undergone adaptive changes, especially in the type of beaks. 
• Therefore, due to the alternation in beaks gradually, some became insectivorous and some vegetarian. 
• Darwin differentiated thirteen species of finches and grouped them into sux main types:
  • Large ground finches
  • Cactus ground finches
  • Vegetarian tree finches
  • Insectivorous tree finches
  • Warbler finches
  • Wood-pecker finches
• Living in isolation for long, the new kinds of finches emerged that could function and survive in the new habitat.

2. Marsupials of Australia:

• A number of marsupials (pouched mammals) each evolved differently from an ancestral stock but all within the Australian continent.

3. Placental Mammals in Australia:

• Placental mammals in Australia also exhibit adaptive radiation in evolving into varieties of such placental mammals each of which appears to be ‘similar’ to a corresponding marsupial. 
• For example, placental wolf and Tasmanian wolf.