Linnaean taxonomy

This system is based on the number and arrangement of male (stamens) and female (pistils) organs.

In the tenth edition, 1758, of the Systema Naturae, the Linnaean classes were: This rank-based method of classifying living organisms was originally popularized by (and much later named for) Linnaeus, although it has changed considerably since his time.

The greatest innovation of Linnaeus, and still the most important aspect of this system, is the general use of binomial nomenclature, the combination of a genus name and a second term, which together uniquely identify each species of organism within a kingdom.

For example, the human species is uniquely identified within the animal kingdom by the name Homo sapiens.

Accordingly, Linnaeus's classification treats animal as a class including many genera (subordinated to the animal "kingdom" via intermediary classes such as "orders"), and treats homo as the genus of a species Homo sapiens, with sapiens (Latin for "knowing" or "understanding") playing a differentiating role analogous to that played, in the Scholastic system, by rationalis (the word homo, Latin for "human being", was used by the Scholastics to denote a species, not a genus).

Among the later subdivisions that have arisen are such entities as phyla, families, and tribes, as well as any number of ranks with prefixes (superfamilies, subfamilies, etc.).

The use of newer taxonomic tools such as cladistics and phylogenetic nomenclature has led to a different way of looking at evolution (expressed in many nested clades) and this sometimes leads to a desire for more ranks.

Originally, Linnaeus established three kingdoms in his scheme, namely for Plants, Animals and an additional group for minerals, which has long since been abandoned.

Since then, various life forms have been moved into three new kingdoms: Monera, for prokaryotes (i.e., bacteria); Protista, for protozoans and most algae; and Fungi.

This five-kingdom scheme is still far from the phylogenetic ideal and has largely been supplanted in modern taxonomic work by a division into three domains: Bacteria and Archaea, which contain the prokaryotes, and Eukaryota, comprising the remaining forms.

[31] Representing presumptive evolutionary relationships within the framework of Linnaean taxonomy is sometimes seen as problematic, especially given the wide acceptance of cladistic methodology and numerous molecular phylogenies that have challenged long-accepted classifications.