CBSE Class 10 Science 2017 · Paper 31/1/C · Question 17

Homologous organs are organs of different organisms that have the same basic structure and the same origin but may perform different functions. Example: the forelimbs of a frog, a lizard, a bird, a bat and a human, which share the same basic arrangement of bones but are used for different purposes, such as supporting the body, flying and grasping. No, the wings of a butterfly and the wings of a bat cannot be regarded as homologous. Both are used for flying, but their basic structure and origin are different: a bat's wing is a modified forelimb, a fold of skin stretched mainly between long finger bones, whereas a butterfly's wing is a thin membrane of the body wall, stiffened by veins, with no bones. Organs with the same function but a different structure and origin are analogous, so these wings are analogous organs.