CBSE · Class 10 · Science · Heredity and EvolutionWhat are analogous organs? How do they differ from homologous organs? Explain with an example.

Analogous organs are those organs in different species that perform the same functional role and superficially look similar, but they have completely different fundamental structural designs and embryonic origins. Unlike homologous organs which indicate common ancestry, analogous organs are the result of convergent evolution, where unrelated species adapt similarly to identical environmental pressures or living conditions. A well-known example of analogous organs is the wings of an insect and the wings of a bat or bird. The wing of a bat is formed by a membrane stretched across skeletal bones derived from mammalian forelimbs, whereas the wing of an insect is a thin membranous extension of the exoskeleton without any internal bone structure. However, both structures serve the common purpose of aerial flight. Similarly, the eyes of an octopus and a vertebrate mammal are analogous because they both function for vision despite having different evolutionary developmental pathways. Therefore, analogous organs illustrate how unrelated organisms can develop similar adaptations for survival.