Write notes on:
(a) Biological species concept.
(b) Evolutionary species concept.

(a) The biological species concept defines a species taxon as a group of organisms that can successfully interbreed and produce fertile offspring. According to this concept, the integrity of a species  is maintained by interbreeding within a species as well as by reproductive barriers between organisms in different species.

(b) According to an evolutionary species concept, a species evolves from a single lineage of ancestors.