Explain the theory of evolution and mention the proof supporting it.

Explanation

(i) According to the theory of evolution, first living material (protoplasm) has been formed in ocean.
(ii) In due course of time, unicellular organism was formed.
(iii) Gradually, changes occurred in the unicellular organism from which larger and more complex organisms were formed. ltbr (iv) All those changes were slow and gradual. Duration of all these changes is about 300 crore years.
(v) Changes and development in living organisms has been all round and multi-dimensional and this led to evolution of different types of organisms.
(vi) Hence, this overall process is called as evolution which is organizational.
(vii) Progressive development of plants and animals from the ancestors having different structural and functional organization is called evolution.
(viii) To support the theroy of evolution, various types of evidence are available.
(ix) Inspite of many adaptive differences in protoplasm and cell, the manifestation of life processes like growth, reproduction, metabolism are essentially same in all organisms.
(x) Morphological evidence support the theory. It is seen that all plants have stem, root, leaf and are green in colour and those having green colour carry out photosynthesis. Similarly, it is seen that animals have appendages, eyes, nose, ears, etc.
(xi) Anatomical evidences like the bone structure of a human arm, a bulls leg, a bat's wing and a whale fin have similar structures attributing that they have developed from common ancestors.
(xii) Vestigial organs like tail ond or coccyx present in humans indicate the link between humans who have lost a tail and monkeys who have a tail.
(xiii) At embryological level, similarities are observed during initial stage which indicates common origin.
(xiv) Thus, there are few evidences which support the fact that evolution in sequential.