Question

What is speciation? What are the factors of speciation? Is geographical barrier a major factor in speciation of a self-pollinating plant species?

Answer 1

Hint: Evolution is modification in the inherited characteristics of biological populations over successive generations. Charles Darwin noted that living organisms change their physical and anatomical structure over generations for better adaptations to the changing environment.

Complete answer:
Speciation is an evolutionary process by which populations evolve to become new and distinct species. It occurs when a category within a species separates from other members of its species and develops its own unique characteristics. These species evolve by genetic modification. The new species are genetically different from one another and can no longer interbreed with the previous species. Speciation is how a new kind of species is created.
The factors of speciation are:
- Natural selection - Process of selection of characteristics and changes that occur during the lifetime of an organism can make better survival in nature than the other, which are passed onto the next generations, we can say they are selected naturally.
- Genetic drift - The change in the frequency of the allele or gene variation occurs randomly and the prevention of gene flow between the different populations is considered. Here mutations also play a chief role to create sudden shifts in gene frequencies.
- Geographical isolation - If geographical barriers are created like a mountain range, a large canyon, a body of water etc. between the groups of species, the gene flow between the different populations is prevented and different populations start evolving separately.
- Reproductive isolation - all the mentioned changes ultimately create enough variations in the organisms that these organisms can no longer interbreed with the older generation resulting in the blockage of gene flow between the members. Thus these individuals evolve into different species.
Geographical barriers won't be a major factor in self- pollinating species because they do not depend on other plants for their pollination. They pollinate in the same plant so no new species would be created. In self- pollinating plants geographical barriers can’t create reproductive isolation. However, there might be some variations due to some environmental changes.

Note: Transfer of pollen grains from a male part of a plant to a female part (stigma) of a plant is called pollination. It enables fertilisation and the production of seeds, often pollination occurs by an animal or by wind