Explain the terms analogous and homologous organs with examples.

Explanation

(1) Homologous organs : Homologous organs are those organs which are structurally similar but functionally dissimilar. Homologous organs help in tracing the relationships and also lead to the divergent evolution. Forelimbs of frog, lizard, bird, bat, whale and man are homologous to each other. All the limbs are morphologically similar in construction but are dissimilar in function. Frog limbs are meant for hopping, lizard limbs help in crawling, birds and bats fly with the help of forelimbs while whale uses it for swimming and man for handling the objects.
(2) Analogous organs : Analogous organs are similar in function but dissimilar in structural details. They do not help to trace the relationship in the evolution but help to understand the convergent evolution. Structural modifications in the organs are due to similar habitat. E.g. wing of an insect and wing of a bird, both are useful in flight so they are functionally similar but are structurally different. Insect wing is formed by exoskeleton expansion while bird wing is the modified forelimb.