DARWIN’S THEORY OF EVOLUTION:
Charles Darwin was an English biologist. He was the first person to propose the theory of evolution in his book, On the Origin of Species (1859). Darwin’s theory of evolution, along with the concepts of genetics, is known as “modern evolutionary synthesis.”
Darwin noted that all living organisms change their physical and anatomical structure over a long period of time to adapt to the changing environment. He also proposed that this change is by natural process and those organisms which do not adhere to it will find difficulty in their survival and named it as ‘Survival of the fittest.’
Darwin’s theory of evolution can be described as follows:
- Within any population, there is natural variation. Some individuals have more favourable variations than others.
- Even though all species produce a large number of offsprings, populations remain fairly constant naturally.
- This is due to the struggle between members of the same species and different species for food, space and mate.
- The struggle for survival within populations eliminates the unfit individuals. The fit individuals possessing favourable variations survive and reproduce. This is called natural selection (or survival of the fittest).
- The individuals having favourable variations pass on these variations to their progeny from generation to generation.
- These variations when accumulated over a long period of time, lead to the origin of a new species.