Explain the terms analogous and homologous organs with examples.

AcademicBiologyNCERTClass 10

Analogous organs:

Analogous organs are organs performing the same functions but have different origins or basic structures inherited from different ancestors.

For example, the wings of insects and birds have the same function of flying but different basic designs.

The organs perform the same function but have different structural designs as they do not share a common ancestor, thus termed convergent evolution. The repeated evolution of flight is a good example of convergent evolution. Flying insects, birds, pterosaurs, and bats all have the ability to fly on their own. 

Homologous organs

Homologous organs are those inherited from common ancestors, having similar basic structures but performing different functions.

For example, the forelimbs of humans, lizards, frogs, birds, etc. have a similar basic design but perform different functions.

The similarity in origin and basic structures is observed as they share a common ancestor, but they differ in functions due to evolution. This is also termed "divergent evolution."  Divergent evolution is the opposite of convergence. This is when similar species change in ways that are different from each other.

Parallel evolution is similar to convergent evolution. Parallel evolution happens when two different species evolve in the same direction and get similar traits. For example, gliding frogs come from different types of tree frogs.

Updated on 10-Oct-2022 13:19:08