Question

Describe Darwin's theory of organic evolution. Add a note on Neo-Darwinism.

Answer 1

Darwin formulated and tested the organic evolution in which the evolution is brought about by the changes in genetic makeup of the individuals, differential behaviour of the environment over the time period and fixation of the character that confers the survival advantage to the individuals. He suggested that all the species have descended from a common ancestor but with gradual modification. Depending on the environment they inhabited, the species accumulated different characters to maintain the fitness and survive. The process of natural selection decided the survival and ultimately a species evolved to another type of species.

Neo-Darwinism brings in the cytological factors, meiotic factors, biochemical factors for the developement of random variations that confer survival advantage or disadvantage. Heritable variations are considered to be important in deciding the survivability. Natural selection was remodelled as successful event of sexual reproduction, giving rise to fertile offsprings.