Binomial nomenclature

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In biology, binomial nomenclature is the formal method of naming species. As the word "binomial" suggests, the scientific name of a species is formed by the combination of two terms: the genus name and the species descriptor. Although the fine detail will differ, there are certain aspects which are universally adopted:

Scientific names are usually printed in italics, such as Homo sapiens. When handwritten they should be underlined.
The first term (genus name / generic name) is always capitalized, while the specific descriptor (in zoology, the "specific name", in botany, the "specific epithet") will not be, even when derived from a proper name. For example, Canis lupus or Anthus hodgsoni. (But note that this is a modern convention: Linnaeus always capitalized the specific descriptor, and up to the early 20th century it was common to capitalize the specific descriptor if it was based on a proper name.)
When used with a common name, the scientific name usually follows in parentheses, for example, "the house sparrow (Passer domesticus) is endangered."
The scientific name should generally be written in full when it is first used or when several species from the same genus are being listed or discussed in the same paper or report. It may then be abbreviated by just using an initial (and period) for the genus; for example Canis lupus becomes C. lupus. In rare cases this abbreviation form has spread to more general use — for example the bacterium Escherichia coli is often referred to as just E. coli, and Tyrannosaurus rex is perhaps even better known simply as T. rex.
The abbreviation "sp." (or "spec.") is used when the actual specific name is not known: for example Canis sp. denotes "a species of the genus Canis". The abbreviation "spp." (plural) indicates "several unknown species".
The abbreviation "cf." is used when the identification is not confirmed: for example Corvus cf. splendens indicates that the species is in doubt.

1 History
2 Value of binomial nomenclature
3 Codes of nomenclature
4 Derivation of names
5 See also
6 External links

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History

The adoption of a system of binomial nomenclature is due to Swedish botanist and physician Carolus Linnaeus (1707–1778) who attempted to describe the entire known natural world and gave every species (mineral, vegetable or animal) a two-part name. However, binomial nomenclature in various forms existed before Linnaeus, and was used by the Bauhins, who lived nearly two hundred years before Linnaeus. Before Linnaeus hardly anybody used binomial nomenclature. After Linnaeus, almost everybody did.

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Value of binomial nomenclature

The value of the binomial nomenclature system derives primarily from its economy, its widespread use, and the stability of names it generally favors:

Every species can be unambiguously identified with just two words.
The same name can be used all over the world, in all languages, avoiding difficulties of translation.
Although such stability as exists is far from absolute, the procedures associated with establishing binomial nomenclature tend to favor stability. For example, when species are transferred between genera (as not uncommonly happens as a result of new knowledge), if possible the species descriptor is kept the same. Similarly if what were previously thought to be distinct species are demoted from species to a lower rank, former species names may be retained as infraspecific descriptors.

Despite the rules favoring stability and uniqueness, in practice a single species may have several scientific names in circulation, depending largely on taxonomic point of view (see synonymy).

A major source of instability is the resurrection of forgotten names, which can claim priority of publication. In this case, however, conservation according to the nomenclature Codes is possible.

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Codes of nomenclature

From the mid nineteenth century onwards it became ever more apparent that a body of rules was necessary to govern scientific names. In the course of time these became Nomenclature Codes governing the naming of animals (ICZN), plants (incl. Fungi, cyanobacteria) (ICBN), bacteria (ICNB) and viruses. These Codes differ.

For example, the ICBN, the plant Code does not allow tautonyms, whereas the ICZN, the animal Code does allow tautonymy.
The starting points, the time from which these Codes are in effect (retroactively), vary from group to group. In botany the starting point will often be in 1753, in zoology in 1758. Bacteriology started anew, with a starting point in 1980Template:Ref).

A BioCode has been suggested to replace several codes, although implementation is not in sight. There also is debate concerning development of a PhyloCode to name clades of phylogenetic trees, rather than taxa. Proponents of the PhyloCode use the name "Linnaean Codes" for the joint existing Codes and "Linnaean taxonomy" for the scientific classification that uses these existing Codes.

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Derivation of names

The genus name and species descriptor may come from any source whatsoever. Often they are Latin words, but they may also come from Ancient Greek, from a place, from a person (preferably a naturalist), a name from a local language, etc. In fact, taxonomists come up with specific descriptors from a variety of sources, including in-jokes and puns.

However, names are always treated grammatically as if they were a Latin sentence. For this reason the name of a species is sometimes called its "Latin name," although this terminology is frowned upon by biologists (and philologists), who prefer the phrase scientific name.

There is a separate list of Latin and Greek words commonly used in systematic names.

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