In Taxonomy, a taxon (of the Greek ταξινομία taxis , “placement”, “put in order”. Greek plural: taxed; French plural: let us tax) is a conceptual entity which is supposed to gather all the Living organisms having jointly certain characters Taxinomique S or diagnostic well defined.
These characters are famous Homogène S according to their row taxinomic, their “weight”, relative taxinomic value, being left with the appreciation of the systematician S.
The species constitutes the basic taxon systematic classification . The more the row of the taxon is raised and the more the degree of resemblance (the number of characters which they have in common) between the individuals concerned (Plante S, animal, Champignon S, Bactérie S) decreases, and conversely.
Definition nomenclaturale
In traditional nomenclature (control by the Codes of nomenclature ), a taxon is:- defined by its district, based on Scientific or taxinomic information , in particular the characters which distinguish it from its close close relations. This information can be of any nature: morphological (anatomical), Biomolecular, Biochemical, Genetic, farming behaviors, etc
- identified by its correct name (name validates sanctioned , with the detriment of the synonymous ). It is information primarily nomenclaturale, concerned with the international codes of nomenclature specific to each discipline.
Row taxinomic
The traditional Classification proposes a hierarchy codified in seven principal rows and five secondary rows, presented, in the decreasing order, in the following way:- alive World: reign → junction, division or Phylum → class → order → family → tribe → kind → section → series → species → variety → form
The Mnemotechnical means to remember it is RECOFGE or RDCOFGE.
The majority of the disciplines admit rows lower than the species (infraspecific): variety (or Race in zoology) and form, to still distinguish more finely and to separate the individuals presenting from the common characters considered stable, but from taxinomic low value. An anatomical difference (for example spores coming by two or Bisporie), or even a simple variation of color of the coating, etc, not requiring the creation of a distinct species. Here than with other rows the personal sensitivity of the taxonomist to the differences and the similarities intervenes more, according to the importance (the weight taxinomic) which it allots to certain characters.
Secondary rows are envisaged by adding the prefix “under” to these principal rows (sub-genus, under variety, etc).
For the rows of kind and above (suprageneric), the “names” are simple names: Agaricales , Asteraceae , Canidae , Bacillus .
Below the row of kind, all the names of let us tax are called combinations. One distinguishes several categories of combinations:
- between kind and species (sub-genus, section, sub-section, series, under-series, etc), the combinations are infrageneric and binominales: name of kind, then after indication of the row, a infrageneric epithet, for example the Cèpe belongs to the section “ Boletus sect. Edules ”;
- with the row of species, the combinations are specific and binominales;
- below the species the combinations are infraspecific and trinominales.
Examples of rows (borrowed from the Zoology):
- Canis lupus , the Wolf, is a taxon with the row of species, lower than that of kind.
- Canis is the taxon immediately higher than the row of kind , which gathers several species: Dog, Wolf, Chacal…
- Canidé S is the taxon immediately higher than the row of family, which gathers several kinds: Canis (Dog, Wolf, Jackal), Vulpes (Fox), Lycaon (lycaon)…
Related articles
- scientific Taxonomy
- Classification (Systematic traditional)
- phylogenetic Classification
- Phylogenetic tree
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