(a) Define 'speciation'. Explain how speciation occurs.
(b) Will geographical isolation be a major factor in the speciation of a self-pollinating plant species? Give the reason for your answer.
(a) The process by which new species develop from the existing ones is known as speciation. Speciation occurs when the population of the same species splits into two separate groups, which then get isolated from each other geographically by barriers such as mountain ranges, rivers or the sea. The geographical isolation of the two groups of the population leads to their reproductive isolation due to which no genes are exchanged between them. However, breeding continues within the isolated populations producing more and more generations. Over the generations, the processes of genetic drift and natural selection operate in different ways in the two isolated groups of population and make them more and more different from each other. After thousands of years, the individuals of these isolated groups of the population become so different that they will be incapable of reproducing with each other, even if they happen to meet again. In this way, two new species have been formed.
(b) Geographical isolation cannot be a major factor in the speciation of self-pollinating plant species, as it does not have to look to other plants for its process of reproduction to be carried out.