Select the correct set of homologous organs - 

• Homologous structures refer to the similar structures that differ in functions.
• Example - Forelimbs of man, wings of birds and flippers of whales.
  • They are all made of humerus, radius, ulna, carpels, metacarpels and phalanges.
  • Flippers are used for swimming, wings for flying and forelimbs of man for grasping.
• These structures have evolved from a common ancestor.
• They show divergent evolution, meaning that they have undergone evolutionary modifications to perform different functions due to varying needs.
• Example - Thorns of Bougainvillea and tendrils of Cucurbita both evolved from branches by modification into thorns for protection and tendrils for support.
• Homologous structures provide evidence in support of biological evolution.

Important Points

• Forelimb of man, wings of birds and flippers of whale: CORRECT
  • ​These are homologous organs because they have similar structures and different functions.
• Forelimb of man, wings of insects and wings of birds: INCORRECT
  • ​These are not homologous because wings of insects membranous and not made of bones.
• Forelimb of man, hind legs of horse, wings of birds: INCORRECT
  • ​The hindlegs of horse does not have same bone structure as the forelimbs of man or wings of birds.
• Forelimb of man, tail of horse, wings of bat: INCORRECT
  • ​The tail of horse does not have similar bone structure as the forelimb of man or wings of bat.

Additional Information

• Analogous structures refer to different structures that perform similar functions.
• It indicates convergent evolution, directed towards a common need.
• Examples -
  • Sweet potato and potato are root and stem modifications respectively but both function as storage organ.
  • Wings of birds are made of bones and feathers while wings of butterfly are membranous, but both are used for flying.