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Binomial nomenclature

life science Maturity 11-13 Next article →

Binomial nomenclature is a formal system used to name every species of living thing. This two-term naming system provides a unique, stable, and verifiable label for organisms. It is essential because common names often change depending on the language or region. A scientific name, also called a binomial or binomen, ensures scientists worldwide understand exactly which species is being discussed.

E coli at 10000x, original
E coli at 10000x, original

The system works by combining two distinct parts into one name. The first part is the generic name, which identifies the genus. A genus is a group of closely related species. The second part is the specific name, or specific epithet, which distinguishes one species from others within that genus. For example, modern humans belong to the genus *Homo*. Our specific name is *sapiens*, making our full binomial name *Homo sapiens*.

Killerwhales jumping
Killerwhales jumping

Writing these names requires following strict rules of formatting. Both parts of the name must be italicized in regular text. If you are writing by hand, you should underline the name instead. The first letter of the generic name is always capitalized. However, the specific epithet always starts with a lowercase letter. This remains true even if the name is derived from a person or a place. For instance, the annual phlox is written as *Phlox drummondii*.

Starr 070320-5799 Echinopsis pachanoi
Starr 070320-5799 Echinopsis pachanoi

Before this system, scientists used polynomial nomenclature. These names were long strings of words used as a diagnosis or description. For example, one plant had a name describing its leaves and spikes. These names were unwieldy and became too long as more species were discovered. Gaspard Bauhin helped transition away from this in 1622 by pruning these long descriptions. However, the modern system was officially introduced by Carl Linnaeus.

Carl von Linné
Carl von Linné

Carl Linnaeus was a Swedish botanist and physician. He began consistently using this two-part system in his 1753 work, *Species Plantarum*. Linnaeus introduced the idea that a name could simply be a unique label. It did not need to be a long description of the organism's features. Because of this, names could be derived from people or places. For example, *Tradescantia virginiana* honors the botanist John Tradescant the Younger.

In scientific works, researchers often include the authority for a name. The authority is the person who first published the name and its description. The year of publication is also often included. For example, "Patella vulgata Linnaeus, 1758" tells us Linnaeus named the species in 1758. If a species is moved to a different genus, parentheses are used. This indicates the species was originally placed in a different group.

The system is governed by international codes to ensure global agreement. The International Code of Zoological Nomenclature (ICZN) manages rules for animals. The International Code of Nomenclature for algae, fungi, and plants (ICNafp) manages the others. These codes provide stability through the principle of priority. This means the earliest published name is generally the correct one. If a species is moved to a new genus, the specific epithet usually stays the same. This keeps the identity of the species constant even as scientific knowledge evolves.

Binomial nomenclature is highly efficient and widely used. It is much shorter and easier to remember than the old polynomial system. Some scientific names have even entered common speech. You may recognize *Tyrannosaurus rex*, *E. coli*, or *Aloe vera*. While there are occasional problems, such as homonyms where names are duplicated, the system remains the standard. It connects naming to the broader field of taxonomy, which is the ordering of items into groups based on similarities.

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🖼️ Images & Media (6)
File:Killerwhales jumping.jpg
Killerwhales jumping.jpg
File:Starr 070320-5799 Echinopsis pachanoi.jpg
Starr 070320-5799 Echinopsis pachanoi.jpg
File:Carl von Linné.jpg
Carl von Linné.jpg
File:E coli at 10000x, original.jpg
E coli at 10000x, original.jpg
File:Petirrojo (Erithacus rubecula superbus ) (6178023045).jpg
Petirrojo (Erithacus rubecula superbus )...
File:Talauma hodgsonii.jpg
Talauma hodgsonii.jpg
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