What are vestigial organs ? Give examples.

Ans. 1. Ill developed structures or structures which are of no use are sometimes found in both plants and animals. They are referred to as vestigial organs. The same organ may be functional in one organism but vestigial in another. 

2. Vermiform appendix of man is one such organ. The reason could be that human ancestors were eating uncooked food with considerable amount of cellulose in it. The normal function of caecum and appendix in mammals is the digestion of cellulose. 

3. Man shows a number of other vestigial organs. About 100 have been named. A few examples are ear muscles, wisdom teeth, plica semilunaris (representing nictitating membrane of the eye), coccyx (reduced tail) etc.

4. In plants, the scale like leaves on the Indian pipe, a plant which has lost its chlorophyll and became saprophytic in nature, are vestigial. 

5. There are certain flowers in which stamens do not bear anthers.