Question

What do you understand by the term 'evolution'? State Darwin's theory of evolution.

Answer 1

Evolution is the sequence of gradual changes which take place in the primitive organisms over millions of years, during which new species are produced.

Darwin's theory of evolution:
(a) Within any population, there is natural selection. Some individuals have more favourable variations than others.
(b) Even though all species produce a large number of offsprings, population remains fairly constant naturally.
(c) This is due to the struggle between members of the same species and different species for food, space and mate.
(d) the struggle within populations eliminates the unfit individuals. The fit individuals possessing favourable variations survive and reproduce. This is called natural selection.
(e) The individuals having favourable variations pass on these variations to their progeny from generation to generation.
(f) These variations when accumulated over a long period of time lead to the origin of new species.