Classification [Based in part on the previous version of this eLS article ‘Classification’ (2012) by Alessandro Minelli].

A biological classification is a hierarchical arrangement of species, subspecific units and higher taxa, with the corresponding scientific nomenclature; classification is also the part of systematic biology concerned with generating such an arrangement. Scientific classifications have ancient roots in folk taxonomies. Between the classical Antiquity and the Renaissance, major conceptual advancement was due to Aristotle and Cesalpino, but modern classifications owe mainly to John Ray and eventually to Linnaeus, who introduced binomial nomenclature. Modern classifications are increasingly aiming to mirror phylogenetic relationships, an effort that may eventually require abandoning the traditional Linnaean ranks such as the genus, the family, the order and the class. Nomenclature is disciplined by international codes – these provide rules for introducing new names and for selecting the names to be used in the case of conflict between synonymous or homonymous names.