Question

Explain the occurrence of vestigial organs on the basis of Lamarck's theory of use and disuse.

Answer 1

Organs which are found in reduced or rudimentary condition and do not perform any function in the possessor are called vestigial organs or non-functional organs. They help in understanding the history of evolution and continuity of life.

 

1. Wisdom teeth: They are the last molars which appear last at the age of 17-20 years.

 

2. Vermiform appendix: It projects from the blind end of the caecum and is a functionless organ in humans. It is helpful in herbivorous mammals.

 

3. Pinna: It is the lobe-like part of the external ear which humans cannot move as in other mammals. As it is poorly developed, it is a vestigial organ.