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Introduction to Biological Classification

Author(s): Deanne Erdmann, MS

Binomial Nomenclature

Early naturalists identified plants and animals by observable structural similarities and referred to organisms using long complicated phrases. This was known as the "polynomial system."  In this system, a plant might be described by phrases of 12 or more words. It is not surprising that polynomial names could become very complex and were often misinterpreted when translated from one language to another.

In the 1700s, Carolus von Linnaeus, sometimes referred to as the Father of Classification, described a binomial system, which was published in his early work, System Naturae (1735). Although he created the two-word system as a short-cut for users of this work, the system was rapidly adopted as a manageable way of naming species.   

In the binomial nomenclature system, genus and species-just two names-replace the long string of words used in the polynomial system. The meaning of words can differ from language to language and from country to country.  For example, in Great Britain, the word "buzzard" refers to an organism Americans call a hawk. For this reason, scientific names are written in Latin to maintain a uniform system of naming across all languages.

In the binomial system, genus is always a noun, underlined (or italicized), and capitalized; species is a descriptive term, underlined (or italicized), and not capitalized. Some examples of binomial names include: Quercus rubra (red oak), Panthera pardus (leopard), or Homo sapiens (human).