How are the hereditary changes responsibole for evolution?

Explanation

(i) Evolution is the gradual changes occuring in living organisms over a long duration.
(ii) Certain heritable sudden changes may occur in the genes of a individual resulting in genetic variations.
(iii) These genetic variations are responsible for the formation of new species from the earlier ones.
(iv) According to Darwin's theory, organisms with favourable or beneficial variations survive in competition and are selected by nature whereas the others with non-favourable variatioins are eliminated.
v. This leads to formation of new species due to specific changes in specific characters accumulated through serveral generations in sustained and selected organisms.