Explain Darwin’s theory of natural selection.

Answer: Charles Darwin explained evolution by the theory of natural selection in his book ‘On the Origin of Species’ (1859). According to it, nature selects the organisms best suited to the environment, and new species form over a long time.

1. Overproduction: all organisms produce far more offspring than can survive.
2. Struggle for existence: food and space are limited, so organisms struggle with members of their own species, with other species and with the environment.
3. Variation: no two organisms are exactly alike; some have variations that are more useful for survival.
4. Survival of the fittest (natural selection): organisms with useful variations survive and reproduce; the others die out.
5. Origin of new species: useful variations are passed on and add up generation after generation, so that over a long period a new species is formed.