(a) Explain the terms ‘analogous organs’ and ‘homologous organs’ with examples.

(b) In what way analogous organs give evolution?

(a) •Homologous organs are those organs which have the same internal structure but perform different functions. These organs share a common ancestry in multiple organisms. They possess a similar structure of origin.

•The arm of a human, the wing of a bird or a bat, the leg of a dog and the flipper of a dolphin or whale are homologous structures.

HOMOLOGOUS ORGANS

•The organs that have different internal structure but same appearance and also perform similar function to survive the prevailing environment are known as analogous organs. They do not share common ancestors and have different origin. They evolve independently of each other.

•The wings in bats, birds, and insects and fins of penguins and fish are examples of analogous structures.

(b) •The organs with different basic design but similar appearance and similar function in different organisms are called analogous organs.

•The wings of insects and the wings of birds have different structure but they perform similar function.

•The presence of analogous organs in different animals gives the evidence that they have not evolved from a common ancestor but they perform similar function to survive in prevailing environment. Analogous structures represent a case of convergent evolution.