The species is a group of actually or potentially interbreeding natural populations which share in a common gene pool, but are reproductively isolated from other such groups. Interbreeding is very frequency among the individuals of a population and is occasional among the populations of a species, whereas interbreeding is absent among the individuals of different species.
It means there is a free gene flow within the members of a population and a free gene flow could be maintained among the members of different populations of a species, provided they have an opportunity to interbreed. Thus there is great potential of origin of new species.
There are two distinct ways of origin of species from the pre-existing one – splitting of the species into two or more species, known as speciation and transformation of the old species into a new one in due course of time known as transformation in time. Species population usually has a discontinuous distribution. Distance plays a significant role in the separation of species population in due course of time. The population of a given species grows in size generation after generation. As a result, the organism radiate into progressively larger territory.