What is speciation? Explain in brief the role of natural selection and genetic drift in this process.

Explanation

Speciation : Origin of new species from pre- existing ones.
Role of Genetic drift and natural selection : Genetic drift is flow of genes from one population to another by chance factor or randomly. Over generation it will accumulate different changes in different population.
In addition, natural selection operates differently in different population selecting the fittest/ favourable feature in both the population. Over a long period of time the differences in the two population may become so drastic that they no longer reproduce with each other and thus give rise to new species.