The concept of a species as a group whose members share certain characteristics that distinguish them from other species. This Aristotelian concept was applied to the natural world by the early taxonomists, but by the late 19th century was being supplanted by other concepts, notably the biological species concept. These could better account for the many cases in which species appear to be virtually indistinguishable (see sibling species) or where intermediate phenotypes occur due to hybridization. However, taxonomists must use a typological approach when attempting to classify exclusively asexual organisms (see agamospecies). See also phylogenetic species concept.
Subjects: Biological Sciences.