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Definition: taxonomy from Philip's Encyclopedia

Organization of plants, animals, and other organisms into categories based on similarities of genetic sequences, appearance, structure or evolution. The categories, from the most inclusive to the exclusive, are: kingdom, phylum, class, order, family, genus, species (the last two of which appear in italics), and sometimes variety. In some categories, there are also subphyla, subfamilies, and so on. Ancient and extinct animals and plants are included in detailed classifications. See also phylogenetics; plant classification


Summary Article: taxonomy from The Penguin Dictionary of Science

The branch of biology concerned with the classification of organisms. Organisms were formerly grouped into various taxa (singular taxon) on the basis of observable anatomical and morphological structures, but nowadays molecular and genetic information is used increasingly, and classification systems are continually being revised as more information becomes available. Cladistics is an approach to classification based on evolutionary relationships and the assumption that organisms that exhibit ➤homologous structures are derived from a common ancestor and are therefore related by genealogy. An organism is classified according to a hierarchical system as follows:

kingdom, phylum, class, order, family, genus, species.

Intermediate categories such as subphylum or superorder may be used in particularly large groups such as flowering plants, in which the term ‘division’ traditionally replaced phylum. The purpose of taxonomy is basically twofold: to provide a means of ready identification of organisms, and to infer and illustrate evolutionary relationships between them. Classification and the naming of organisms are closely related. All organisms have a binomial Latinized name based on the ➤Linnaean system. ➤➤Appendix table 8.

Copyright © M. J. Clugston, 1998, 2004, 2009, 2014

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