Organs, which have a common fundamental anatomical plan and similar embroyonic origin whatever varied functions they may perform are regarded as homologous organs. For instances the flippers of a whale, a bats wing, fore-limb of a horse, a birds wing and forelimbs of human are structurally as well as functionally different . Whale’ this flippers help in swimming, wings of birds and bat are used in flying, horse’ this forelimb help in running and human’s hand is meant for grasping.
They are structurally modified accordingly. However, anatomically they have similar bones, humerus in the upper arm, radius ulna in the forearm, carpals and metacarpals in the wrist and hand. Presence of homologous organs in different groups of animals indicates their common origin or ancestry and degree of closeness to difference among various groups.