11.1 Classification and Cladistics

Taxonomy is the science of identifying, naming and grouping organisms. In binomial nomenclature, each species receives a two-part scientific name: the genus followed by the specific epithet. The genus begins with a capital letter, the second word is lower case, and both are italicized when printed, as in Homo sapiens. After the first complete use, the genus may be abbreviated, as in H. sapiens. A standardized name avoids the ambiguity of local common names and signals a proposed relationship to other members of the genus.

A species is often defined as a group whose members can interbreed and produce fertile offspring. This biological species concept emphasizes gene flow and reproductive isolation. Species boundaries remain scientific hypotheses and may be revised when independent evidence reveals a different history.