Question

List three factors that provide evidences in favour of evolution in organisms and state the role of each in brief.

 

 

Answer 1

Homologous organs:  The homologous organs are similar in form (or are embryologically similar), but perform different functions in different organisms. The bone structure observed in wings of birds, flippers of dolphins and arms of human beings is similar, but they perform different functions. They belong to the same group of animals, the vertebrates, and therefore, exhibit homology.
Analogous organs: The organs that perform similar functions in different organisms of different origins are analogous. For example, wings of birds and wings of bats (bird wings are made of feathers, while bat wings are folds of skin) exhibit analogy. Both are used for flight, but they are structurally different. Also, they are found in organisms which are not related.

Fossils: Fossils are the remains of organisms that once existed on Earth. They represent the ancestors of plants and animals, which are alive even today.

Vestigial organs: Organs that are present in a reduced form and do not play any role in the normal body functions are known as vestigial organs. These organs are remnants of the organs that were once complete and functional in the ancestors, but disappeared gradually either because of a change in the mode of life or because they became non-functional.