Linné’s binomial nomenclature

Portrait of Carl Linnaeus

Science requires a language of it’s own to differentiate from colloquial language. In order to study life, scientists must utilize a common precise language to describe organisms. The Swedish physician and scientist Carl von Linné developed a systematic hierarchy to organize life and binomial nomenclature to precisely name organisms in his publication Systema Naturae. Linné’s binomial nomenclature named individual species of organisms using two-part Latin names consisting of a genus and species (Homo sapiens). Inspired by this system, he applied this to himself and wrote under the Latinized name Carolus Linnæus. A species name must be written as capital Genus and lower case species in italics or underlined to properly illustrate a species name.

Carolus Linnæus was not the first to use a binomial system, but he used it consistently across Systema Naturae and is known as the father of taxonomy for organizing life into a nested hierarchy of relatedness. Modern taxonomy classifies organisms from broadest to most specific: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species. These divisions can further be divided by using the prefix super- and sub-.

Main taxonomic ranks of the red fox

All life on earth follow the same basic instruction sets and are utilize chemical information transfer in a similar fashion. Three domains exist: Archaea, Bacteria and Eukarya. Archaea and Bacteria are also grouped together as Prokaryotes (pro– before; karya– nucleus). Eukarya (eu– true; karya– nucleus), or eukaryotes, is a group of of organisms that have nuclei. The second most inclusive or broad category is Kingdom. Humans are in the Kingdom of animals.  The third most inclusive or broad category is Phylum. Humans are in the phylum called chordata. Each level of organization can be further subdivided and you may be more familiar with the subphylum called vertebrata. Within the this division, humans fall in the class of mammals. Amongst the mammals, humans are in the order of primates. Humans are categorized into a narrower group of organisms in the family of great apes or hominids. Within this family, humans fall into the genus of Homo. Biologists use a method of identifying specific organisms called binomial nomenclature. Binomial nomenclature  uses the most specific groupings of taxonomy (genus and species) as a two part name. While humans are of the species sapiens, the species name of humans using binomial nomenclature is Homo sapiens.

Disambiguation

The precision of binomial nomenclature allows a common language to name organisms without ambiguity of vernacular or regional language. In the US, the word buzzard denotes a carrion consuming bird like a vulture. However, in the UK, buzzard describes an active hunting bird.

Pale Male w/ dinner
Pale Male, a red-tailed hawk (Buteo jamaicensis). In the United States he is identified as a hawk. In the United Kingdom he is identified as a buzzard. Credit: Jeremy Seto [CC-BY-NC-SA]

Relationship of all life

“A phylogenetic tree of living things, based on RNA data and proposed by Carl Woese, showing the separation of bacteria, archaea, and eukaryotes. Trees constructed with other genes are generally similar, although they may place some early-branching groups very differently, thanks to long branch attraction. The exact relationships of the three domains are still being debated, as is the position of the root of the tree. It has also been suggested that due to lateral gene transfer, a tree may not be the best representation of the genetic relationships of all organisms. For instance some genetic evidence suggests that eukaryotes evolved from the union of some bacteria and archaea (one becoming an organelle and the other the main cell).”