Question

How do reproductive barriers relate to the biological species concept?

Answer 1

The biological species concept is a theory that explains how the species are formed (a concept which is known as speciation). It states that a species is a group of organisms that can interbreed and produce fertile offspring.

Complete answer:
The biological species concept not only describes species as a reproductive group of organisms, but it also explains why an organism of one species cannot be reproduced by an organism of another species, as the integrity of a species is maintained only by interbreeding within the species. This phenomenon is known as the reproductive barrier. Thus, a species is a group of organisms that are reproductively isolated from the other organisms. The term “reproductively isolated” is therefore the correct definition of a species. Both pre-zygotic and post-zygotic barriers are useful for preventing interbreeding between different species.

The biological species concept depends upon the theory of group differentiation into different species when they cannot mate. When a species lives in two different geographical areas, they start developing distinct features according to their habitat, eventually, they become so different that interbreeding between them is favored very less, and this leads to the formation of two different species. Thus, reproductive barriers avoid two different populations of species from reproducing and favoring the production of unique species (species divergence).

Note: The biological species concept also describes that it is not always true that all the organisms of a species would be similar in appearance, but still, they would be able to reproduce naturally. Appearance is an important feature in identifying a species, however, it is not the only criteria to define a species.