The biological species concept defines species by the ability to interbreed and produce fertile offspring, emphasizing gene flow within a species. Its limits include extinct organisms, asexual species and cases where distinct forms exchange genes.
Discuss the definition of the term species.
meaning of species has changed over time / no longer just based on morphological features/phenotype
species members also resemble each other in physiology/biochemistry/DNA sequences/use of habitat/behaviour
but species can evolve and features change/species gradually split up
definition now based on ability to interbreed/produce viable, fertile offspring
gene flow among populations of the species maintains the species' uniqueness
some interspecific hybrids are fertile making categorization difficult