Bihar BoardEnglish MediumSTD 12 ScienceBIOLOGYEvolution5 Marks
Question
Describe the evidence of evolution from comparative anatomy and morphology?
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Answer
Morphological and comparative anatomical evidences:
The phylogenetic history can be revealed by comparative study of external and internal structures.
The organs with same structural design and origin but different functions are called homologous organs. For example, the forelimbs of some animals like whales, bats and cheetah have similar anatomical structure, i.e., humerus, radius, ulna, carpals, metacarpals and phalanges.
Due to different needs, some structures developed differently. This is called divergent evolution.
Other examples include vertebrate hearts or brains in animals; thorn and tendrils of Bougainvillea and cucurbita in plants.
The organs which are anatomically different but functionally similar are called analogous organs. For example, wings of butterfly and birds.
Due to same function, different structures evolve similarly. This is called convergent evolution.
Other examples include eye of octopus and mammals; flippers of penguins and dolphins; sweet potato (root modification) and potato (stem modification).
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