6.8: Taxonomy

The process of naming and classifying organisms according to set of rules is called taxonomy. In some cultures, taxonomic rules are based on traditional uses for plants and animals, and the existence of a classification system facilitates the transfer of that knowledge through generations. In modern scientific culture, taxonomic rules are based on physical appearance as well as genetic and evolutionary relationships between species, but having a classification system serves a very similar purpose by allowing scientists to communicate efficiently and effectively about the nature of a given organism with only a few words.

Naturalists in the 17th century, such as John Ray, began to develop a scientific basis for recognizing species. Ray and others began to inventory species by arranging them into logical classes based on their appearance and characteristics. However, multiple names were given to a single species and names were created in different languages.

In the 18th century, the Swedish scientist Carolus Linnaeus more or less invented our modern system of taxonomy and classification. Linnaeus was one of the leading naturalists of the 18th century, a time when the study of natural history was considered one of the most prestigious areas of science.

Unlike his predecessors, Linnaeus adhered rigidly to the principle that each species must be identified by a set of names, which are termed the "genus" and "species," and classified on the basis of their similarities and differences. Although he was primarily a botanist, Linnaeus produced a comprehensive list of all organisms then known worldwide, some 7,700 plant and 4,400 animal species. He wrote one of the great classic works in the history of science, SystemaNaturæ, and revised it many times.

Under Linnaeus's system, every species is known by a unique Latin-sounding genus and species name that distinguishes it from other species. Linnaeus's work organized organisms into logical classes based on their appearance and characteristics, and thus provides a basis for comparing different species.

The solution that Linnaeus adopted was the consistent use of a two-name system called binomialnomenclature. He recognized that by giving every species a fixed pair of names, analogous to our "family" and "given" names, each one could be designated uniquely. The titles for the two official names were those that John Ray, a British naturalist, had proposed a century earlier, the genus and species. In practice, these terms are tied together and used in combination. The combination is presented as a sequence, first the genus name (plural genera, related to the word generic) and then the species name (plural species, related to the word specific), as in the binomial Homo sapiens Moving from the point of origin, the groups become more specific, until one branch ends as a single species. For example, after thecommon beginning of all life, scientists divide organisms into three large categories called a domain: Bacteria, Archaea, and Eukarya. Within each domain is a second category called a Kingdom. After Kingdoms, the subsequent categories of increasing specificity are: Phylum, Class, order, Family, Genus, and Species.

Figure \(\PageIndex{1}\): Species Classification. The illustration shows the classification of a dog, which belongs in the domain Eukarya, Kingdom Animalia, Phylum Chordata, Class Mammalia, Order Carnivora, Family Canidae, Genus Canis, and species Canis Lupus

http://www.oercommons.org/courses/taxonomy-what-s-in-a-name/view

http://www.oercommons.org/courses/taxonomy-ii-nomenclature-ruling-names-of-giants/view

https://www.oercommons.org/courseware/module/15036/overview

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