Explanation

Darwin’s theory of natural selection based on the following observation (i) Limited natural resources (ii) Stable population size except seasonal fluctuation (iii) Varying characteristics of the members of a population (iv) Most variation are inherited (v) Varying characteristics enable some population or individuals to survive better in natural condition (survival of the fittest) (vi) Those population which better fit (reproductive fit) in an environment will be selected by the nature and will surive more (natural selection) Examples Industrial melanism Chemical resistance But this theory does not explains the origin of new variation, because Darwin was unaware about the genetics