biological species concept

biological species concept (BSC) The concept of a species as a group of populations whose members are capable of interbreeding successfully and are reproductively isolated from other groups. This concept became influential during the late 19th and early 20th centuries, largely replacing the typological species concept favoured by pioneer naturalists. Central to the concept is the role of sexual reproduction. This maintains the broad uniformity of species' members through genetic recombination and sharing of a common gene pool. Isolating mechanisms prevent breeding, and hence gene flow, between different groups, thus ensuring genetic divergence between groups. However, the concept cannot be applied to exclusively asexual organisms, such as certain groups of fungi and bacteria. Nor does it account satisfactorily for the many instances in which interspecies mating does occur, especially in plants, fungi, and prokaryotes.