. Explain with an example for each, how the following provides evidences in favour of evolution in organisms:

(a) Homologous organs (b) Analogous organs (c) Fossils


Best Answer

Ans.(a) Homologous organs. Those organs, which have the same basic structure but different functions, are called homologous organs.

For example: The forelimbs of a man, a frog, a lizard, a bird and a bat have the same basic design of bonus but they perform different functions.

The presence of homologous organs in different animals provides evidence for evolution that they are derived from the same ancestor who has the basic design of the organs on which all the homologous organs are based.

(b) Analogous organs. Those organs, which have different basic structure but

have similar appearance and perform similar functions are called analogous organs.

For example: The wings of an insect and a bird have different structure but they perform the same function of flying.

Analogous organs provide evidence for evolution that the organisms from different ancestors perform similar functions to survive, flourish and keep on evolving in prevailing environment.

(iii) Fossils. The remains of dead animal or plants that lived in

the remote past are known as fossils. The fossils provide evidence for evolution.

For example: A fossil of a bird called archaeopteryx looks like a bird but it has many other features found in reptiles. Therefore archaeopteryx is a connecting link between the reptiles and birds hence suggests that the bird have evolved from the reptiles.


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