The two-part scientific name assigned to every organism provides a universally recognized label that transcends language barriers and regional common names. This naming convention, known as binomial nomenclature, was developed by Swedish botanist Carl Linnaeus in the 18th century. Scientific names ensure that a researcher referring to Homo sapiens, for instance, is discussing the exact same species, avoiding the confusion of common names.
The Genus Name
The first component of an organism’s scientific name is the Genus name, which acts as a broad categorization for a group of closely related species. This name is always capitalized and is treated grammatically as a noun in Latin form. For example, the genus Canis groups together species like the grey wolf (Canis lupus) and the coyote (Canis latrans).
A genus can contain many different species, or it may be monotypic, containing only a single recognized species. The genus name is foundational to biological classification, ranking above the species level and below the family level.
The Species Epithet
The second part of the scientific name is the species epithet, which serves to distinguish a species from others within the same genus. This epithet is never capitalized, even when derived from a proper noun, such as a place or a person’s name. For example, in the name Escherichia coli, the epithet coli refers to the colon, where the bacterium was first identified.
The specific epithet is meaningless without the genus name preceding it. Numerous unrelated species may share the same epithet, such as albus (meaning white). The full species name, or binomen, requires the combination of both the capitalized genus and the lowercase epithet to be a unique identifier.
The Naming Authority
A third, optional element is the Naming Authority, which identifies the person who first formally described and published the species. This component is included in scientific literature to track the history of the name and ensure taxonomic verification. The authority is typically the surname of the original describer, sometimes followed by the year of publication.
Naming conventions differ slightly between fields. In botanical nomenclature, the authority’s name is usually abbreviated, such as “L.” for Linnaeus, and the year is optional. Zoological nomenclature traditionally cites the full surname followed by the year, as in Patella vulgata Linnaeus, 1758. If the species has been moved to a different genus, the original author’s name is placed in parentheses.
Formatting Rules and Usage
The presentation of a scientific name is governed by precise mechanical rules. The most recognizable formatting rule is the mandatory use of italics for both the genus and the species epithet when typed. When handwritten, this is indicated by underlining the two parts separately.
The full two-part name must be written out upon the first mention in a document, but it can be abbreviated in subsequent references. Abbreviation involves using only the first letter of the genus name, followed by a period and the full species epithet, such as changing Canis lupus to C. lupus.
The capitalization rules remain constant, with the genus initial capitalized and the species epithet lowercase, even when abbreviated. The genus name must be spelled out in full if it begins a sentence.