Question

Explain the term analogous and homologous organs with examples.

Answer 1

Hint: The comparative anatomical and morphological studies show some similarities and differences between the organisms that are present today and those that existed years ago; in other words, these are the evidence of how evolution might have occurred. The occurrence of homologous and analogous organs shows such evidence.

Complete answer:
Morphology means the external structure of an organism while anatomy points towards the internal structural and functional organization.
Homologous organs: These organs have similar anatomy i.e., similar structures but differ in their functions.
-These organs point towards common ancestry.
-Embryonic development is the same.
-The homologous organs show divergent evolution.
-They have different structures due to adaptations to different needs.
Examples-
a. Forelimbs of mammals like man, cheetah, whale and bat etc.
b. Thorns of Bougainvillea and tendril of Cucurbita.
c. Vertebrate heart and brains.
d. Mouth part of insects.
e. Testes and ovary- having the same origin.
Analogous organs: These organs are not similar anatomically but perform similar functions.
-These do not exhibit a common origin.
-They show convergent evolution.
Examples-
a. Wings of butterflies and birds.
b. Eye of Octopus and mammals.
c. Flippers of penguins and dolphins.
d. Potato (stem modification) and sweet potato (root modification).

Note: Convergent evolution is the process by which organisms with different evolutionary history evolve similar phenotypic adaptations in response to a common environmental challenge. Divergent evolution This evolution occurs in closely related species. Gradually, this kind of evolution gives rise to new species. Migration or environmental changes could be the reason behind this evolution.