Question

Write a short note on Darwin’s theory of Natural Selection.

Answer 1

Hint: Leading to his contribution to the development of the theory of evolution, Charles Darwin is regarded as the father of evolution. The evolutionary theory of natural selection by Darwin offered a more logical explanation for the creation of new organisms.

Complete answer:
Darwin proposed Natural selection as a mechanism for evolution. Because resources are limited in nature, organisms that favour survival and reproduction with heritable characteristics will tend to leave more offspring than their peers, causing the characteristics to increase in frequency over generations.
The idea of natural selection by Darwin was based on several key observations:
1.Often, traits are inheritable. Many features are inherited, or passed from parent to offspring, in living organisms. (Darwin knew that even though he did not know that traits were inherited through genes, this was the case.)

2.More offspring than can survive are produced. Organisms are able to produce more offspring than can be supported by their environments. Thus, in each generation, competition for limited resources exists.

3.The offspring vary in their inherited characteristics. In their traits (colour, size, shape, etc the offspring in any generation will be slightly different from each other and many of these characteristics will be inheritable.

Darwin concluded the following on the basis of these easy observations:
a.Some individuals will have inherited characteristics in a population that help them survive and reproduce (given the environmental conditions, such as the predators and food sources present). In the next generation people with helpful characteristics will leave more offspring than their peers, as the characteristics make them more effective in surviving and reproducing.

b.Since the helpful characteristics are heritable, and because organisms with these characteristics leave more offspring, in the next generation the characteristics will tend to become more common (present in a larger fraction of the population).

c.The population will become adapted to its environment over generations (as people with characteristics helpful in that environment have consistently greater reproductive success than their peers).

Note: 1.Natural Selection is dependent on the environment.
2.Natural selection reflects current inherited variation
3.Heritable variation is attributed to random mutation.