Question

Explain with example how natural selection direct the survival of population.

Answer 1

That is, it is limited to the selection process itself, whereby individuals in a population experience differential survival and reproduction based on a particular phenotypic variation(s). ... More inclusive definitions define natural selection as the process and a resulting change in the gene-frequency of the population.

Answer 2

Explanation of how natural selection directs the survival of population by considering moth as an example:

In England before, industrialization the population of white winged moth was considerably high when compared to the black winged moth. In is because the thick growth of white colored lichens on the tree act as background in which white winged moths were invisible to the predators and black winged moth were visible and thus they were killed and eaten by the predators.

On the other hand, in the same scenario, post industrialization era, due to emission of smoke and gases, the trees were fully covered with black color due to which the white winged moths became visible and black winged moth became invisible to the predators.  

This shows that in a mixed population, the species which has the ability to adapt its natural environment can survive and increase in population and those without it will get extinct.