In biological classification, rank is the level (the relative position) in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, and class.
Each rank subsumes under it a number of less general categories. The rank of species, and specification of the genus to which the species belongs is basic, which means that it may not be necessary to specify ranks other than these.
The International Code of Zoological Nomenclature defines rank as:
The level, for nomenclatural purposes, of a taxon in a taxonomic hierarchy (e.g. all families are for nomenclatural purposes at the same rank, which lies between superfamily and subfamily)
"2.1. Every individual plant is treated as belonging to an indefinite number of taxa of consecutively subordinate rank, among which the rank of species (species) is basic."
In his landmark publications, such as the Systema Naturae, Carolus Linnaeus used a ranking scale limited to: kingdom, class, order, genus, species, and one rank below species. Today, nomenclature is regulated by the nomenclature codes. There are seven main taxonomic ranks: kingdom, phylum or division, class, order, family, genus, species. In addition, the domain (proposed by Carl Woese) is now widely used as one of the fundamental ranks, although it is not mentioned in any of the nomenclature codes.
| Main taxonomic ranks | |||
| Latin | English | ||
| regio | domain | ||
| regnum | kingdom | ||
| phylum | divisio | phylum | division |
| classis | class | ||
| ordo | order | ||
| familia | family | ||
| genus | genus | ||
| species | species | ||
A taxon is usually assigned a rank when it is given its formal name. The basic ranks are species and genus. When an organism is given a species name it is assigned to a genus, and the genus name is part of the species name.
The species name is also called a binomial, that is, a two-term name. For example, the zoological name for the human species is Homo sapiens. This is usually italicized in print and underlined when italics are not available. In this case, Homo is the generic name and it is capitalized; sapiens indicates the species and it is not capitalized.
There are definitions of the following taxonomic ranks in the International Code of Zoological Nomenclature: superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies.
The International Code of Zoological Nomenclature divides names into "family-group names", "genus-group names" and "species-group names". The Code explicitly mentions:
The rules in the Code apply to the ranks of superfamily to subspecies, and only to some extent to those above the rank of superfamily. In the "genus group" and "species group" no further ranks are allowed. Among zoologists, additional terms such as species group, species subgroup, species complex and superspecies are sometimes used for convenience as extra, but unofficial, ranks between the subgenus and species levels in taxa with many species (e.g., the genus Drosophila).
At higher ranks (family and above) a lower level may be denoted by adding the prefix "infra", meaning lower, to the rank. For example infraorder (below suborder) or infrafamily (below subfamily).
According to Art 3.1 of the International Code of Nomenclature for algae, fungi, and plants (ICN) the most important ranks of taxa are: kingdom, division or phylum, class, order, family, genus, and species. According to Art 4.1 the secondary ranks of taxa are tribe, section, series, variety and form. There is an indeterminate number of ranks. The ICN explicitly mentions:
primary ranks
kingdom (regnum)
division or phylum (divisio, phylum)
class (classis)
order (ordo)
family (familia)
genus (genus)
species (species)
There are definitions of the following taxonomic ranks in International Code of Nomenclature for Cultivated Plants: cultivar group, cultivar.
The rules in the ICN apply primarily to the ranks of family and below, and only to some extent to those above the rank of family. Also see descriptive botanical names.
Of the botanical ranks used by Linnaeus only names of genera, species and varieties are still used.
Taxa at the rank of genus and above get a botanical name in one part (unitary name); those at the rank of species and above (but below genus) get a botanical name in two parts (binary name); all taxa below the rank of species get a botanical name in three parts (an infraspecific name).
Hybrids can be specified either by a "hybrid formula" that specifies the parentage, or may be given a name. For hybrids getting a hybrid name, the same ranks apply, preceded by "notho", with nothogenus as the highest permitted rank.
If a different term for the rank was used in an in old publication, but the intention is clear, botanical nomenclature specifies certain substitutions:
Classifications of five species follow: the fruit fly so familiar in genetics laboratories (Drosophila melanogaster), humans (Homo sapiens), the peas used by Gregor Mendel in his discovery of genetics (Pisum sativum), the "fly agaric" mushroom Amanita muscaria, and the bacterium Escherichia coli. The eight major ranks are given in bold; a selection of minor ranks are given as well.
| Rank | Fruit fly | Human | Pea | Fly Agaric | E. coli |
|---|---|---|---|---|---|
| Domain | Eukarya | Eukarya | Eukarya | Eukarya | Bacteria |
| Kingdom | Animalia | Animalia | Plantae | Fungi | Bacteria |
| Phylum or Division | Arthropoda | Chordata | Magnoliophyta | Basidiomycota | Proteobacteria |
| Subphylum or subdivision | Hexapoda | Vertebrata | Magnoliophytina | Agaricomycotina | |
| Class | Insecta | Mammalia | Magnoliopsida | Agaricomycetes | Gammaproteobacteria |
| Subclass | Pterygota | Theria | Rosidae | Agaricomycetidae | |
| Order | Diptera | Primates | Fabales | Agaricales | Enterobacteriales |
| Suborder | Brachycera | Haplorrhini | Fabineae | Agaricineae | |
| Family | Drosophilidae | Hominidae | Fabaceae | Amanitaceae | Enterobacteriaceae |
| Subfamily | Drosophilinae | Homininae | Faboideae | Amanitoideae | |
| Genus | Drosophila | Homo | Pisum | Amanita | Escherichia |
| Species | D. melanogaster | H. sapiens | P. sativum | A. muscaria | E. coli |
Taxa above the genus level are often given names based on the type genus, with a standard termination. The terminations used in forming these names depend on the kingdom, and sometimes the phylum and class, as set out in the table below. Pronunciations given are the most Anglicized; more Latinate pronunciations are also common, particularly /ɑː/ rather than /eɪ/ for stressed a.
| Rank | Bacteria | Plants | Algae | Fungi | Animals |
|---|---|---|---|---|---|
| Division/Phylum | -phyta /ˈfaɪtə/ | -mycota /maɪˈkoʊtə/ | |||
| Subdivision/Subphylum | -phytina /fɨˈtaɪnə/ | -mycotina /maɪkɵˈtaɪnə/ | |||
| Class | -ia /iə/ | -opsida /ˈɒpsɨdə/ | -phyceae /ˈfaɪʃiː/ | -mycetes /maɪˈsiːtiːz/ | |
| Subclass | -idae /ɨdiː/ | -phycidae /ˈfɪsɨdiː/ | -mycetidae /maɪˈsɛtɨdiː/ | ||
| Superorder | -anae /ˈeɪniː/ | ||||
| Order | -ales /ˈeɪliːz/ | ||||
| Suborder | -ineae /ˈɪnɨ.iː/ | ||||
| Infraorder | -aria /ˈɛəri.ə/ | ||||
| Superfamily | -acea /ˈeɪʃə/ | -oidea /ˈɔɪdi.ə/ | |||
| Epifamily | -oidae /ˈɔɪdiː/ | ||||
| Family | -aceae /ˈeɪʃiː/ | -idae /ɨdiː/ | |||
| Subfamily | -oideae /ˈɔɪdɨ.iː/ | -inae /ˈaɪniː/ | |||
| Infrafamily | -odd /ɒd/ | ||||
| Tribe | -eae /ɨ.iː/ | -ini /ˈaɪnaɪ/ | |||
| Subtribe | -inae /ˈaɪniː/ | -ina /ˈaɪnə/ | |||
| Infratribe | -ad /æd/ | ||||
There is an indeterminate number of ranks, as a taxonomist may invent a new rank at will, at any time, if they feel this is necessary. In doing so, there are some restrictions, which will vary with the nomenclature code which applies.
The following is an artificial synthesis, solely for purposes of demonstration of relative rank (but see notes), from most general to most specific:
Ranks are assigned based on subjective dissimilarity, and do not fully reflect the gradational nature of variation within nature. In most cases, higher taxonomic groupings arise further back in time: not because the rate of diversification was higher in the past, but because each subsequent diversification event results in an increase of diversity and thus increases the taxonomic rank assigned by present-day taxonomists.
Of these many ranks, the most basic is species. However, this is not to say that a taxon at any other rank may not be sharply defined, or that any species is guaranteed to be sharply defined. It varies from case to case. Ideally, nowadays, a taxon is intended to represent a clade, that is, the phylogeny of the organisms under discussion, but this is not a requirement.
Classification, in which all taxa have formal ranks, cannot adequately reflect our knowledge about phylogeny; at the same time, if taxa names are dependent on ranks, rank-free taxa can't be supplied with names. This problem is dissolved in cladoendesis, where the specially elaborated rank-free nomenclatures are used.
HOT DESIGNS ▪ Premium designs ▪ Designs by country ▪ Designs by U.S. state ▪ Most popular designs ▪ Newest, last added designs ▪ Unique designs ▪ Cheap, budget designs ▪ Design super sale DESIGNS BY THEME ▪ Accounting, audit designs ▪ Adult, sex designs ▪ African designs ▪ American, U.S. designs ▪ Animals, birds, pets designs ▪ Agricultural, farming designs ▪ Architecture, building designs ▪ Army, navy, military designs ▪ Audio & video designs ▪ Automobiles, car designs ▪ Books, e-book designs ▪ Beauty salon, SPA designs ▪ Black, dark designs ▪ Business, corporate designs ▪ Charity, donation designs ▪ Cinema, movie, film designs ▪ Computer, hardware designs ▪ Celebrity, star fan designs ▪ Children, family designs ▪ Christmas, New Year's designs ▪ Green, St. Patrick designs ▪ Dating, matchmaking designs ▪ Design studio, creative designs ▪ Educational, student designs ▪ Electronics designs ▪ Entertainment, fun designs ▪ Fashion, wear designs ▪ Finance, financial designs ▪ Fishing & hunting designs ▪ Flowers, floral shop designs ▪ Food, nutrition designs ▪ Football, soccer designs ▪ Gambling, casino designs ▪ Games, gaming designs ▪ Gifts, gift designs ▪ Halloween, carnival designs ▪ Hotel, resort designs ▪ Industry, industrial designs ▪ Insurance, insurer designs ▪ Interior, furniture designs ▪ International designs ▪ Internet technology designs ▪ Jewelry, jewellery designs ▪ Job & employment designs ▪ Landscaping, garden designs ▪ Law, juridical, legal designs ▪ Love, romantic designs ▪ Marketing designs ▪ Media, radio, TV designs ▪ Medicine, health care designs ▪ Mortgage, loan designs ▪ Music, musical designs ▪ Night club, dancing designs ▪ Photography, photo designs ▪ Personal, individual designs ▪ Politics, political designs ▪ Real estate, realty designs ▪ Religious, church designs ▪ Restaurant, cafe designs ▪ Retirement, pension designs ▪ Science, scientific designs ▪ Sea, ocean, river designs ▪ Security, protection designs ▪ Social, cultural designs ▪ Spirit, meditational designs ▪ Software designs ▪ Sports, sporting designs ▪ Telecommunication designs ▪ Travel, vacation designs ▪ Transport, logistic designs ▪ Web hosting designs ▪ Wedding, marriage designs ▪ White, light designs E-COMMERCE DESIGNS ▪ Magento store designs ▪ OpenCart store designs ▪ PrestaShop store designs ▪ CRE Loaded store designs ▪ Jigoshop store designs ▪ VirtueMart store designs ▪ osCommerce store designs ▪ Zen Cart store designs CMS DESIGNS ▪ Flash CMS designs ▪ Joomla CMS designs ▪ Mambo CMS designs ▪ Drupal CMS designs ▪ WordPress blog designs ▪ Forum designs ▪ phpBB forum designs ▪ PHP-Nuke portal designs ANIMATED WEBSITE DESIGNS ▪ Flash CMS designs ▪ Silverlight animated designs ▪ Silverlight intro designs ▪ Flash animated designs ▪ Flash intro designs ▪ XML Flash designs ▪ Flash 8 animated designs ▪ Dynamic Flash designs ▪ Flash animated photo albums ▪ Dynamic Swish designs ▪ Swish animated designs ▪ jQuery animated designs WEBSITE DESIGNS ▪ WebMatrix Razor designs ▪ HTML 5 designs ▪ Web 2.0 designs ▪ 3-color variation designs ▪ 3D, three-dimensional designs ▪ Artwork, illustrated designs ▪ Clean, simple designs ▪ CSS based website designs ▪ Full design packages ▪ Full ready websites ▪ Portal designs ▪ Stretched, full screen designs ▪ Universal, neutral designs CORPORATE ID DESIGNS ▪ Corporate identity sets ▪ Logo layouts, logo designs ▪ Logotype sets, logo packs ▪ PowerPoint, PTT designs ▪ Facebook themes VIDEO, SOUND & MUSIC ▪ Video e-cards ▪ After Effects video intros ▪ Special video effects ▪ Music tracks, music loops ▪ Stock music bank GRAPHICS & CLIPART ▪ Pro clipart & illustrations, $19/year ▪ 5,000+ icons by subscription ▪ Icons, pictograms |
| Super Offers |
| Super Offers |
| Custom Logo Design $149 ▪ Web Programming ▪ ID Card Printing ▪ Best Web Hosting ▪ eCommerce Software ▪ Add Your Link |
| © 1996-2013 MAGIA Internet Studio ▪ About ▪ Portfolio ▪ Photo on Demand ▪ Hosting ▪ Advertise ▪ Sitemap ▪ Privacy ▪ Maria Online
|
