The organs P and Q of two animals have different structures but similar functions. On the other hand, the two organs R and S of two other animals have the same basic structure but different functions.

(a) What are the organs like P and Q known as?

(b) Name the organs like P and Q. Also name the animals which have such organs.

(c) What are the organs like R and S called?

(d) Name the organs like R and S. Also name the animals which have such organs.

(a) These organs that have different basic structure but perform similar functions are known as analogous organs. So organs P and Q are analogous organs.

(b) Wings of a Butterfly and wings of a sparrow; wing of an insect and wing of a bird.

(c) These organs that have similar basic structure but perform different functions are known as homologous organs. So organs R and S are homologous organs

(d) Forelimbs; Forelimbs of a frog and forelimbs of human are homologous.