Taxonomic rank . Taxonomic rank 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[1]. 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] Main ranks "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, Carl Linnaeus used a ranking scale limited to: kingdom, class, order, genus, species, and one lower rank, below species. Today, nomenclature is regulated by the Nomenclature Codes, which allow names divided into an indefinite number of ranks.

There are seven main taxonomic ranks: kingdom, phylum or division (see table), 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 1 used in zoology 2 used in botany A taxon is usually assigned a taxonomic rank (in a hierarchy), usually when it is given its formal name. The basic rank is that of species. The next most important rank is that of genus: if an organism is given a species name it will at the same time be assigned to a genus, as the genus name is part of the species name. The third-most important rank, although it was not used by Linnaeus, is that of family. The species name is sometimes called a binomial (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 refers to the genus; it is capitalized; sapiens indicates the species: it is written in lower case. Ranks in zoology 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: Superfamily Species Subspecies 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). Names of zoological taxa * A taxon above the rank of species gets a scientific name in one part (a uninominal name) * A species (a taxon at the rank of species) gets a name composed of two names (a binomial name or binomen : generic name + specific name; for example Panthera leo, the lion). * A subspecies (a taxon at the rank of subspecies) gets a name composed of three names (a trinomial name or trinomen : generic name + specific name + subspecific name; for example Canis lupus familiaris, the house dog). As there is only one rank below that of species, no connecting term to indicate rank is used.

Ranks in botany There are definitions of the following taxonomic ranks in the International Code of Botanical Nomenclature: kingdom (regnum), subregnum, division or phylum (divisio, phylum), subdivisio or subphylum, class (classis), subclassis, order (ordo), subordo, family (familia), subfamilia, tribe (tribus), subtribus, genus (genus), subgenus, section (sectio), subsectio, series (series), subseries, species (species), subspecies, variety (varietas), subvarietas, form (forma), subforma. There are definitions of following taxonomic ranks in International Code of Nomenclature for Cultivated Plants: cultivar group, cultivar. According to Art 3.1 of the ICBN 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 ICBN explicitly mentions: primary ranks form (forma) subforma The rules in the ICBN 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. Names of botanical taxa Of the botanical names 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 (ternary name). For hybrids getting a hybrid name, the same ranks apply, preceded by "notho", with nothogenus as the highest permitted rank.

(The hybrid's nothotaxon is an alias for a list of all of the taxa which are ancestral to the hybrid.) Examples 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 E. coli Notes: * The ranks of higher taxa, especially intermediate ranks, are prone to revision as new information about relationships is discovered. For example, the traditional classification of primates (class Mammalia — subclass Theria — infraclass Eutheria — order Primates) has been modified by new classifications such as McKenna and Bell (class Mammalia — subclass Theriformes — infraclass Holotheria) with Theria and Eutheria assigned lower ranks between infraclass and the order Primates. See mammal classification for a discussion.

These differences arise because there are only a small number of ranks available and a large number of branching points in the fossil record. * Within species further units may be recognised. Animals may be classified into subspecies (for example, Homo sapiens sapiens, modern humans) or morphs (for example Corvus corax varius morpha leucophaeus, the Pied Raven). Plants may be classified into subspecies (for example, Pisum sativum subsp. sativum, the garden pea) or varieties (for example, Pisum sativum var. macrocarpon, snow pea), with cultivated plants getting a cultivar name (for example, Pisum sativum var. macrocarpon 'Snowbird'). Bacteria may be classified by strains (for example Escherichia coli O157:H7, a strain that can cause food poisoning). * Mnemonics are available at[3] and.[4] Terminations of names 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 -ad /æd/ Table notes: * In botany and mycology names at the rank of family and below are based on the name of a genus, sometimes called the type genus of that taxon, with a standard ending. For example, the rose family Rosaceae is named after the genus Rosa, with the standard ending "-aceae" for a family. Names above the rank of family are formed from a family name, or are descriptive (like Gymnospermae or Fungi). * For animals, there are standard suffixes for taxa only up to the rank of superfamily.[7] * Forming a name based on a generic name may be not straightforward. For example, the Latin "homo" has the genitive "hominis", thus the genus "Homo" (human) is in the Hominidae, not "Homidae". * The ranks of epifamily, infrafamily and infratribe (in animals) are used where the complexities of phyletic branching require finer-than-usual distinctions.

Although they fall below the rank of superfamily, they are not regulated under the International Code of Zoological Nomenclature and hence do not have formal standard endings. The suffixes listed here are regular, but informal.[8] All ranks There is an indeterminate number of ranks, as a taxonomist may invent a new rank at will, at any time, if he or she feels 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:[9] Domain or Empire Subspecies (or Forma Specialis for fungi, or Variety for bacteria[13]) Variety (botany) or Form/Morph (zoology) Subvariety (botany) Form (botany) Subform (botany) 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 the phylogeny of the organisms under discussion, but in itself this is not a requirement. Notes 1. ^ International Code of Botanical Nomenclature Online, Vienna Code, 2005, articles 2 and 3 2. ^ International Commission on Zoological Nomenclature (1999) International Code of Zoological Nomenclature. Fourth Edition. - International Trust for Zoological Nomenclature, XXIX + 306 pp. 3. ^ mnemonic-device.eu 5. ^ Bacteriologocal Code (1990 Revision) 6. ^ For example, the chelonian infrafamilies Chelodd (Gaffney & Meylan 1988: 169) and Baenodd (ibid., 176). 7. ^ ICZN article 27.2 8. ^ As supplied by Gaffney & Meylan (1988). 9. ^ For the general usage and coordination of zoological ranks between the phylum and family levels, including many intercalary ranks, see Carroll (1988).

For additional intercalary ranks in zoology, see especially Gaffney & Meylan (1988); McKenna & Bell (1997); Milner (1988); Novacek (1986, cit. in Carroll 1988: 499, 629); and Paul Sereno's 1986 classification of ornithischian dinosaurs as reported in Lambert (1990: 149, 159). For botanical ranks, including many intercalary ranks, see Willis & McElwain (2002). 10. ^ a b c d e f g h In zoological classification, the cohort and its associated group of ranks are inserted between the class group and the ordinal group. In botanical classification, the cohort group is inserted between the division (phylum) group and the class group: see Willis & McElwain (2002: 100–101). The cohort has also been used between infraorder and family in saurischian dinosaurs (Benton 2005). 11.

^ a b c d These are movable ranks, most often inserted between the class and the legion or cohort. Nevertheless, their positioning in the zoological hierarchy may be subject to wide variation. For examples, see the Benton classification of vertebrates (2005). 12. ^ a b c d e The supra-ordinal sequence gigaorder-megaorder-capaxorder-hyperorder (and the microorder, in roughly the position most often assigned to the parvorder) has been employed in turtles at least (Gaffney & Meylan 1988), while the parallel sequence magnorder-grandorder-mirorder figures in recently influential classifications of mammals. It is unclear from the sources how these two sequences are to be coordinated (or interwoven) within a unitary zoological hierarchy of ranks. Previously, Novacek (1986) and McKenna-Bell (1997) had inserted mirorders and grandorders between the order and superorder, but Benton (2005) now positions both of these ranks above the superorder. 13.

^ Additionally, the terms biovar, morphovar and serovar designate bacterial strains (genetic variants) that are physiologically or biochemically distinctive. These are not taxonomic ranks, but are groupings of various sorts which may define a bacterial subspecies. Bibliography * Benton, Michael J. 2005. Vertebrate Palaeontology, 3rd ed. Oxford: Blackwell Publishing. ISBN 0-632-05637-1. ISBN 978-0-632-05637-8 * Brummitt, R.K., and C.E. Powell. 1992. Authors of Plant Names. Royal Botanic Gardens, Kew. ISBN 0947643443 * Carroll, Robert L. 1988. Vertebrate Paleontology and Evolution. New York: W.H. Freeman & Co. ISBN 0-716-7-1822-7 * Gaffney, Eugene S., and Peter A. Meylan. 1988. "A phylogeny of turtles". In M.J.

Benton (ed.), The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds, 157–219. Oxford: Clarendon Press. * International Association for Plant Taxonomy. 2000. International Code of Botanical Nomenclature (Saint Louis Code), Electronic version. Retrieved on 2007-07-21. * Haris Abba Kabara. Karmos hand book for botanical names. * Lambert, David. 1990. Dinosaur Data Book. Oxford: Facts On File & British Museum (Natural History). ISBN 0-8160-2431-6 * McKenna, Malcolm C., and Susan K. Bell (editors). 1997. Classification of Mammals Above the Species Level. New York: Columbia University Press. ISBN 0-231-11013-8 * Milner, Andrew. 1988. "The relationships and origin of living amphibians". In M.J.

Benton (ed.), The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds, 59–102. Oxford: Clarendon Press. * Novacek, Michael J. 1986. "The skull of leptictid insectivorans and the higher-level classification of eutherian mammals". Bulletin of the American Museum of Natural History 183: 1–112. * Sereno, Paul C. 1986. "Phylogeny of the bird-hipped dinosaurs (Order Ornithischia)". National Geographic Research 2: 234–56. * Willis, K.J., and J.C. McElwain. 2002. The Evolution of Plants. Oxford University Press. ISBN 0-19-850065-3 See also Taxonomic rank Privacy & Advertising Taxonomic rank This graph shows the main taxonomic ranks: domain, kingdom, phylum, class, order, family, genus, and species. Here it demonstrates how taxonomic ranking is used to classify animals and earlier life forms related to the red fox, Vulpes vulpes .

[1] The hierarchy of biological classification ‘s eight major taxonomic ranks. Intermediate minor rankings are not shown. In biological classification , rank is the relative level of a group of organisms (a taxon ) in a taxonomic hierarchy . Examples of taxonomic ranks are species , genus , family , order , class , phylum , kingdom , domain , etc. A given rank subsumes under it less general categories, that is, more specific descriptions of life forms. Above it, each rank is classified within more general categories of organisms and groups of organisms related to each other through inheritance of traits or features from common ancestors. The rank of any species and the description of its genus is basic; which means that to identify a particular organism, it is usually not necessary to specify ranks other than these first two. [2] Consider a particular species, the red fox Vulpes vulpes : its next rank, the genus Vulpes , comprises all the ‘true foxes’.

Their closest relatives are in the immediately higher rank, the family Canidae , which includes dogs, wolves, jackals, all foxes, and other caniforms such as bears, badgers and seals; the next higher rank, the order Carnivora , includes feliforms and caniforms (lions, tigers, hyenas, wolverines, and all those mentioned above), plus other carnivorous mammals . As one group of the class Mammalia , all of the above are classified among those with backbones in the Chordata phylum rank, and with them among all the animals in the Animalia kingdom rank. Finally, all of the above will find their earliest relatives somewhere in their domain rank Eukarya . 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) [3] Contents 9.1 Bibliography Main ranks 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. Also, this term represents a synonym for the category of dominion (lat. dominium), introduced by Moore in 1974. [4] Unlike Moore, Whoese et al. (1990) did not suggest a Latin term for this category, which represents a further argument supporting the accurately introduced term dominion. [5] Main taxonomic ranks 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. Ranks in zoology 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: Superfamily Subspecies 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). Names of zoological taxa A taxon above the rank of species has a scientific name in one part (a uninominal name). A species has a name composed of two parts (a binomial name or binomen ): generic name + specific name ; for example Canis lupus. A subspecies has a name composed of three parts (a trinomial name or trinomen ): generic name + specific name + subspecific name ; for example Canis lupus familiaris. As there is only one possible rank below that of species, no connecting term to indicate rank is needed or used.

Ranks in botany 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: [6] primary ranks There are definitions of the following taxonomic categories in the International Code of Nomenclature for Cultivated Plants : cultivar group , cultivar , grex . 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 . Names of botanical taxa Taxa at the rank of genus and above have a botanical name in one part (unitary name); those at the rank of species and above (but below genus) have a botanical name in two parts ( binary name ); all taxa below the rank of species have a botanical name in three parts (an infraspecific name ). To indicate the rank of the infraspecific name, a “connecting term” is needed.

Thus Poa secunda subsp. juncifolia, where “subsp.” is an abbreviation for “subspecies”, is the name of a subspecies of Poa secunda . 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, prefixed with notho (Greek: ‘bastard’), with nothogenus as the highest permitted rank. Outdated names for botanical ranks If a different term for the rank was used in an old publication, but the intention is clear, botanical nomenclature specifies certain substitutions: If names were “intended as names of orders, but published with their rank denoted by a term such as”: “cohors” [Latin for "cohort"; [7] see also cohort study for the use of the term in ecology], “nixus”, “alliance”, or “Reihe” instead of “order” (Article 17.2), they are treated as names of orders.

“Family” is substituted for “order” (ordo) or “natural order” (ordo naturalis) under certain conditions where the modern meaning of “order” was not intended. (Article 18.2) “Subfamily is substituted for “suborder” (subordo) under certain conditions where the modern meaning of “suborder” was not intended. (Article 19.2) In a publication prior to 1 January 1890, if only one infraspecific rank is used, it is considered to be that of variety. (Article 37.4) This commonly applies to publications that labelled infraspecific taxa with Greek letters, α, β, γ, … Examples 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 -ad or -iti Table notes In botany and mycology names at the rank of family and below are based on the name of a genus, sometimes called the type genus of that taxon, with a standard ending. For example, the rose family Rosaceae is named after the genus Rosa, with the standard ending “-aceae” for a family. Names above the rank of family are also formed from a generic name, or are descriptive (like Gymnospermae or Fungi ). For animals, there are standard suffixes for taxa only up to the rank of superfamily. [11] Forming a name based on a generic name may be not straightforward. For example, the Latin “homo” has the genitive “hominis“, thus the genus “Homo” (human) is in the Hominidae , not “Homidae”. The ranks of epifamily, infrafamily and infratribe (in animals) are used where the complexities of phyletic branching require finer-than-usual distinctions. Although they fall below the rank of superfamily, they are not regulated under the International Code of Zoological Nomenclature and hence do not have formal standard endings.

The suffixes listed here are regular, but informal. [12] All ranks 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: [13] Subform (botany) Significance and problems 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. [18] Furthermore, some groups have many described species not because they are really very diverse, but due to the fact of being more easily sampled and studied than other groups. 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, 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 taxon 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. [19] [20] There are no rules for how many species should make a genus, a family, or any other higher taxon (that is, a taxon in a category above the species level). [21] [22] It should be a natural group (that is, non-artificial, non- polyphyletic ), as judged by a biologist, using all the information available to them.

Equally ranked higher taxa in different phyla are not necessarily equivalent (e.g., it is incorrect to assume that families of insects are in some way evolutionarily comparable to families of mollusks). [22] For animals, at least the phylum rank is usually associated with a certain body plan , which is also, however, an arbitrary criterion. See also ^ For example, the chelonian infrafamilies Chelodd (Gaffney & Meylan 1988: 169) and Baenodd (ibid., 176). ^ ICZN article 29.2 ^ As supplied by Gaffney & Meylan (1988). ^ For the general usage and coordination of zoological ranks between the phylum and family levels, including many intercalary ranks, see Carroll (1988). For additional intercalary ranks in zoology, see especially Gaffney & Meylan (1988); McKenna & Bell (1997); Milner (1988); Novacek (1986, cit.

in Carroll 1988: 499, 629); and Paul Sereno ‘s 1986 classification of ornithischian dinosaurs as reported in Lambert (1990: 149, 159). For botanical ranks, including many intercalary ranks, see Willis & McElwain (2002). ^ a b c d These are movable ranks, most often inserted between the class and the legion or cohort. Nevertheless, their positioning in the zoological hierarchy may be subject to wide variation. For examples, see the Benton classification of vertebrates (2005). ^ a b c d In zoological classification, the cohort and its associated group of ranks are inserted between the class group and the ordinal group. The cohort has also been used between infraorder and family in saurischian dinosaurs ( Benton 2005).

In botanical classification, the cohort group has sometimes been inserted between the division (phylum) group and the class group: see Willis & McElwain (2002: 100–101), or has sometimes been used at the rank of order, and is now considered to be an obsolete name for order: See International Code of Nomenclature for algae, fungi, and plants, Melbourne Code 2012, Article 17.2. ^ a b c d e The supra-ordinal sequence gigaorder-megaorder-capaxorder-hyperorder (and the microorder, in roughly the position most often assigned to the parvorder) has been employed in turtles at least (Gaffney & Meylan 1988), while the parallel sequence magnorder-grandorder-mirorder figures in recently influential classifications of mammals. It is unclear from the sources how these two sequences are to be coordinated (or interwoven) within a unitary zoological hierarchy of ranks.

Previously, Novacek (1986) and McKenna-Bell (1997) had inserted mirorders and grandorders between the order and superorder, but Benton (2005) now positions both of these ranks above the superorder. ^ Additionally, the terms biovar , morphovar and serovar designate bacterial strains (genetic variants) that are physiologically or biochemically distinctive. These are not taxonomic ranks, but are groupings of various sorts which may define a bacterial subspecies. ^ Gingerich, P. D. (1987). “Evolution and the fossil record: patterns, rates, and processes”. Canadian Journal of Zoology. 65 (5): 1053–1060. doi : 10.1139/z87-169 . ^ Kluge N.J. 1999. A system of alternative nomenclatures of supra-species taxa. Linnaean and post-Linnaean principles of systematics. // Entomological Review 79(2): 133-147 ^ Kluge N.J. 2010.

Circumscriptional names of higher taxa in Hexapoda. // Bionomina 1: 15–55 ^ Stuessy, T.F. (2009). Plant Taxonomy: The Systematic Evaluation of Comparative Data. 2nd ed. Columbia University Press, p. 175. ^ a b Brusca, R.C. & Brusca, G.J. (2003). Invertebrates. 2nd ed. Sunderland, Massachusetts: Sinauer Associates, pp. 26-27. Bibliography Taxonomic rank - wikidoc Taxonomic rank Jump to: navigation , search Taxonomic rank (rank, category, taxonomic category) is an abstract term used in the scientific classification , or taxonomy , of organisms. Taxonomic rank indicates the level of a taxon in the taxonomic hierarchy. Taxa ranked at a particular taxonomic rank are groupings of organisms at the same classification level. The International Code of Zoological Nomenclature defines rank, in the taxonomic sense, 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). The ranks of the family group, the genus group, and the species group at which nominal taxa may be established are stated in Articles 10.3, 10.4, 35.1, 42.1 and 45.1. ” —International Commission on Zoological Nomenclature (1999) International Code of Zoological Nomenclature. Fourth Edition. - International Trust for Zoological Nomenclature, XXIX + 306 pp. Main taxonomic ranks Carl Linnaeus devised Linnaean taxonomy using a ranking scale: kingdom, class, order, genus, species, and variety. Today, nomenclature is regulated by the Nomenclature Codes , which allow names divided into exactly defined ranks. Despite this there are slightly different ranks for zoology and for botany. There are 8 main taxonomic ranks: domain, kingdom, phylum or division1, class, order, family, genus, species. Main taxonomic ranks 1 Phylum is used in zoology. It is at the same level as division in botany.

2 Preferred to phylum in botany, that is accounted as identical. In zoology and in botanical nomenclature , a taxon is usually assigned to a taxonomic rank in a hierarchy. The basic rank is that of species, and if an organism is named it most often will receive a species name. The next most important rank is that of genus : if an organism is given a species name it will at the same time be assigned to a genus, as the genus name is part of the species name. The third-most important rank, although it was not used by Linnaeus, is that of family . A binomial is a two-word name which is used to describe a particular species. For example, the binomial name for a human is Homo sapiens. This is italicised when typing, and underlined when writing. The first word refers to the genus, which is a broad grouping of closely related species, and is capitalized. The second word, in lower case, always indicates the species to which the organism is assigned within its genus.

Ranks in zoology 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: - - - superfamily species - - - subspecies 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 ranks 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 ). Ranks of taxa at lower levels may be denoted in their groups by adding the prefix "infra," meaning lower, to the rank. For example infraspecies or infrasubspecies. Infraspecific taxa then include all divisions of the species into subspecies or lower taxa.

Names of zoological taxa A taxon above the rank of species gets a scientific name in one part (a uninominal name) A species (a taxon at the rank of species) gets a name composed of two names (a binominal name or binomen : generic name + specific name ; for example Panthera leo ) A subspecies (a taxon at the rank of subspecies) gets a name composed of three names (a trinominal name or trinomen : generic name + specific name + subspecific name ; for example Felis silvestris catus, the house cat ). As there is only one rank below that of species, no connecting term to indicate rank is used.

Ranks in botany There are definitions of the following taxonomic ranks in the International Code of Botanical Nomenclature : kingdom (regnum), subregnum, division or phylum (divisio, phylum), subdivisio or subphylum, class (classis), subclassis, order (ordo), subordo, family (familia), subfamilia, tribe (tribus), subtribus, genus (genus), subgenus, section (sectio), subsectio, series (series), subseries, species (species), subspecies, variety (varietas), subvarietas, form (forma), subforma. There are definitions of following taxonomic ranks in International Code of Nomenclature for Cultivated Plants : cultivar group, cultivar. According to Art 3.1 of the ICBN 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 ICBN explicitly mentions: primary ranks - - - form (forma) - - - - - - - subforma The rules in the ICBN 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 . Names of botanical taxa Of the botanical names 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 ( ternary name ). For hybrids, getting a hybrid name , the same ranks apply, preceded by "notho", with nothogenus as the highest permitted rank.

Examples The usual 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 E. coli Table Notes: The ranks of higher taxa, especially intermediate ranks, are prone to revision as new information about relationships is discovered. For example, the traditional classification of primates (class Mammalia — subclass Theria — infraclass Eutheria — order Primates) has been modified by new classifications such as McKenna and Bell (class Mammalia — subclass Theriformes — infraclass Holotheria) with Theria and Eutheria assigned lower ranks between infraclass and the order Primates. See mammal classification for a discussion. These differences arise because there are only a small number of ranks available and a large number of branching points in the fossil record. Within species further units may be recognised.

Animals may be classified into subspecies (for example, Homo sapiens sapiens, modern humans) or morphs (for example Corvus corax varius morpha leucophaeus, the Pied Raven). Plants may be classified into subspecies (for example, Pisum sativum subsp. sativum, the garden pea) or varieties (for example, Pisum sativum var. macrocarpon, snow pea), with cultivated plants getting a cultivar name (for example, Pisum sativum var. macrocarpon 'Snowbird'). Bacteria may be classified by strains (for example Escherichia coli O157:H7 , a strain that can cause food poisoning ). A mnemonic for remembering the order of the taxa is: Do Koalas Prefer Chocolate Or Fruit, Generally Speaking? Another easy one is Damn, Kinky People Can Often Find Great Sex. Other mnemonics are available at [1] and. [2] Terminations of names 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. Rank -ad Table notes: In botany and mycology names at the rank of family and below are based on the name of a genus, sometimes called the type genus of that taxon, with a standard ending. For example, the rose family Rosaceae is named after the genus Rosa, with the standard ending "-aceae" for a family. Names above the rank of family are formed from a family name, or are descriptive (like Gymnospermae or Fungi ). For animals, there are standard suffixes for taxa only up to the rank of superfamily. [5] Forming a name based on a generic name may be not straightforward. For example, the Latin "homo" has the genitive "hominis", thus the genus "Homo" (human) is in the Hominidae , not "Homidae". The ranks of epifamily, infrafamily and infratribe (in animals) are used where the complexities of phyletic branching require finer-than-usual distinctions.

Although they fall below the rank of superfamily, they are not regulated under the International Code of Zoological Nomenclature and hence do not have formal standard endings. The suffixes listed here are regular, but informal. [6] All taxonomic ranks Taxonomic rank | Psychology Wiki | Fandom powered by Wikia Animals · Animal ethology · Comparative psychology · Animal models · Outline · Index Taxonomic rank (rank, category, taxonomic category) is abstract term used in taxonomy used in scientific classification of organism. Taxonomic rank indicates the level of taxon in taxonomic hierarchy. Taxons ranked in certain taxonomic ranks are real groups of real organisms at real classification level. Definition of taxonomic rank (there called only a rank) in International Code of Zoological Nomenclature: “ 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).

The ranks of the family group, the genus group, and the species group at which nominal taxa may be established are stated in Articles 10.3, 10.4, 35.1, 42.1 and 45.1. ” —International Commission on Zoological Nomenclature (1999) International Code of Zoological Nomenclature. Fourth Edition. - International Trust for Zoological Nomenclature, XXIX + 306 pp. Contents Edit Carl Linnaeus devised Linnaean taxonomy and he used five ranks: class, order, genus, species, and variety. Today, nomenclature is regulated by Nomenclature Codes , which allows names divided into exactly defined ranks. Despite this there are slightly different ranks for zoology and different ranks for botany . Ranks in zoology and in botany Main article: Rank (zoology) There are definitions of the following taxonomic ranks in International Code of Zoological Nomenclature : superfamily, family, subfamily, tribe, subtribe, genus, subgenus, species, subspecies.

There are definitions of the following taxonomic ranks in International Code of Botanical Nomenclature : kingdom (regnum), subregnum, division or phylum (divisio, phylum), subdivisio or subphylum, class (classis), subclassis, order (ordo), subordo, family (familia), subfamilia, tribe (tribus), subtribus, genus (genus), subgenus, section (sectio), subsectio, series (series), subseries, species (species), subspecies, variety (varietas), subvarietas, form (forma), subforma. There are definition of following taxonomic ranks in International Code of Nomenclature for Cultivated Plants : cultivar group, cultivar. Main taxonomic ranks There are 8 main taxonomic ranks: domain, kingdom, phylum or division1,class, order, family, genus, species. This article may require cleanup to meet Wikipedia's quality standards . E. coli Table Notes: The ranks of higher taxa, especially intermediate ranks, are prone to revision as new information about relationships is discovered.

For example, the traditional classification of primates (class Mammalia — subclass Theria — infraclass Eutheria — order Primates) has been modified by new classifications such as McKenna and Bell (class Mammalia — subclass Theriformes — infraclass Holotheria) with Theria and Eutheria assigned lower ranks between infraclass and the order Primates. See mammal classification for a discussion. These differences arise because there are only a small number of ranks available and a large number of branching points in the fossil record. Within species further units may be recognised. Animals may be classified into subspecies (for example, Homo sapiens sapiens, modern humans) or morphs (for example Corvus corax varius morpha leucophaeus, the Pied Raven). Plants may be classified into subspecies (for example, Pisum sativum subsp. sativum, the garden pea) or varieties (for example, Pisum sativum var. macrocarpon, snow pea), with cultivated plants getting a cultivar name (for example, Pisum sativum var. macrocarpon 'Snowbird').

Bacteria may be classified by strains (for example Escherichia coli O157:H7 , a strain that can cause food poisoning ). A mnemonic for remembering the order of the taxa is: Do Koalas Prefer Chocolate Or Fruit, Generally Speaking? Another easy one is Damn, Kinky People Can Often Find Great Sex. Other mnemonics are available at [1] and. [2] Terminations of names -ad Table notes: In botany and mycology names at the rank of family and below are based on the name of a genus, sometimes called the type genus of that taxon, with a standard ending. For example, the rose family Rosaceae is named after the genus Rosa, with the standard ending "-aceae" for a family. Names above the rank of family are formed from a family name, or are descriptive (like Gymnospermae or Fungi ). For animals, there are standard suffixes for taxa only up to the rank of superfamily. [4] Forming a name based on a generic name may be not straightforward.

For example, the Latin "homo" has the genitive "hominis", thus the genus "Homo" (human) is in the Hominidae , not "Homidae". The ranks of epifamily, infrafamily and infratribe (in animals) are used where the complexities of phyletic branching require finer-than-usual distinctions. Although they fall below the rank of superfamily, they are not regulated under the International Code of Zoological Nomenclature and hence do not have formal standard endings. The suffixes listed here are regular, but informal. [5] All taxonomic ranks There are written all taxonomic ranks including those ones that are not in use today or those ones that are identical with another ranks. All taxonomic ranks in more languages (zoology and botany) Latin Taxon - New World Encyclopedia Taxon Next (Taxonomy) The hierarchy of scientific classification's major eight taxonomic ranks. Intermediate minor rankings are not shown. Taxon (plural taxa) is the name designating a taxonomic grouping, such as species , genus , order, or phylum (or division), of either living or extinct organisms . Another name for taxon is taxonomic unit.

For example, the Lepus genus comprising the hares is a particular taxon of the kingdom Animalia ( animals ), and the division Pinophyta comprising the conifers is one of 13 or 14 division-level taxa within the kingdom Plantae ( plants ). Taxonomy in the field of biology involves categorizing like organisms into particular groups. Each taxonomic grouping, or taxon, is assigned a taxonomic rank and can be placed at a particular level in a systematic hierarchy, traditionally reflecting shared physical characteristics but more recently aiming to reflect evolutionary relationships. The eight major taxonomic ranks, starting from the individual organism, are species, genus, family, order, class, phylum (or division), kingdom, and domain. There also are intermediate minor rankings between these, such as subclass, subspecies, and superfamily. Classifying the members of the biological world into various taxa reflects the desire of human beings to group the great diversity of living and extinct organisms into natural categories—particularly identifying groupings according to their connectedness based on lineage or evolutionary relatedness. Contents 6 Credits Overview Biologists group and categorize both extinct and living species of organisms by using the conceptual framework of scientific (or biological) classification .

Scientific classifications, or taxonomies , are frequently hierarchical in structure. Taxon designates a particular taxonomic grouping of organisms. Mammals , for example, are a taxon of vertebrate animals. They comprise the class Mammalia. Taxonomic rank (rank, category, taxonomic category) refers to the level of a taxon in the taxonomic hierarchy. Taxa placed at a particular taxonomic rank are groupings of organisms at the same classification level. The eight major categories used to rank organisms are species, genus, family, order, class, phylum or division, kingdom, and domain. (In biology, the terms "division" and "phylum" occupy the same taxonomic rank: "phylum" is applied traditionally to animals while "division" is more commonly applied to plants and fungi.) A simple mnemonic phrase to remember the sequence of taxonomic levels is "Dignified Kings Play Chess On Fine Green Silk." Others include "King Philip's Class Orders the Family Genius to Speak," or Do Koalas Prefer Chocolate Or Fruit, Generally Speaking? Biologists use a prefix added to one of the eight major ranking categories to indicate finer distinctions of rank than are possible with the eight major categories.

The prefix super- indicates a rank above, the prefix sub- indicates a rank below. In zoology, the prefix infra- indicates a further rank distinction below sub-. For instance: Superclass The International Code of Zoological Nomenclature defines rank, in the taxonomic sense, 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). The ranks of the family group, the genus group, and the species group at which nominal taxa may be established are stated in Articles 10.3, 10.4, 35.1, 42.1 and 45.1. ” —International Commission on Zoological Nomenclature (1999) Whereas modern classification has its roots in the system of Carolus Linnaeus , who grouped species according to shared physical characteristics, modern groupings have been revised since Linnaeus to reflect the Darwinian principle of common descent .

In differentiating between the Linnaeus-based classification, which is used for biological naming, and modern classification, scientists make a distinction between taxa/taxonomy and classification/systematics. The former refers to biological names and the rules of naming. The latter refers to rank ordering of taxa according to presumptive evolutionary (phylogenetic) relationships. An organism's rank is relative and restricted to a particular systematic schema. For example, liverworts have been grouped, in various systems of classification, as a family, order, class, or division (phylum). Crustaceans ( Crustacea ) are variously grouped as a phylum, subphylum, superclass, or class. The use of a narrow set of ranks is challenged by users of cladistics . For example, the mere 10 ranks traditionally used between animal families (governed by the ICZN) and animal phyla (usually the highest relevant rank in taxonomic work) often cannot adequately represent the evolutionary history, as more about a lineage's phylogeny becomes known.

In addition, the class rank is quite often not an evolutionary but a phenetic and paraphyletic group and as opposed to those ranks governed by the ICZN, can usually not be made monophyletic by exchanging the taxa contained therein. This has given rise to phylogenetic taxonomy and the ongoing development of the PhyloCode, which is to govern the application of taxa to clades. Main taxonomic ranks Carolus Linnaeus devised Linnaean taxonomy using a six-level ranking scale: kingdom, class, order, genus, species, and variety. Today's nomenclature remains quite similar in its foundations to that established by Linnaeus, with the addition of the two major ranks of phylum and family and a de-emphasis on variety. The nomenclature is regulated by the Nomenclature Codes, which allow names divided into exactly defined ranks. Despite this there are slightly different ranks for zoology and botany . In both zoology and botany , a taxon is usually assigned to a taxonomic rank in a hierarchy and organisms are identified by combining the two lowest major ranks in today's nomenclature, genus and species. The resulting binomial, a two-word name, is widely used to describe a particular species.

For example, the binomial name for a human is Homo sapiens. This is italicized when typing, and underlined when writing. The first word refers to the genus, which is a broad grouping of closely related species, and is capitalized. The second word, in lower case, always indicates the species to which the organism is assigned within its genus. Ranks in zoology 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: - - - superfamily species - - - subspecies The rules in the Code apply to the ranks from 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 ranks 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 ). Ranks of taxa at lower levels may be denoted in their groups by adding the prefix "infra," meaning lower, to the rank. For example infraspecies or infrasubspecies. Infraspecific taxa then include all divisions of the species into subspecies or lower taxa. Note: A taxon above the rank of species gets a scientific name in one part (a uninominal name). A species (a taxon at the rank of species) gets a name composed of two names (a binominal name or binomen : generic name + specific name; for example Panthera leo). A subspecies (a taxon at the rank of subspecies) gets a name composed of three names (a trinominal name or trinomen : generic name + specific name + subspecific name; for example Felis silvestris catus, the house cat ).

As there is only one rank, subspecies, below that of species, the subspecific name follows the specific name directly with no intermediate term to identify the subspecific rank. Ranks in botany There are definitions of the following taxonomic ranks in the International Code of Botanical Nomenclature (ICBN): kingdom (regnum), subregnum, division or phylum (divisio, phylum), subdivisio or subphylum, class (classis), subclassis, order (ordo), subordo, family (familia), subfamilia, tribe (tribus), subtribus, genus (genus), subgenus, section (sectio), subsectio, series (series), subseries, species (species), subspecies, variety (varietas), subvarietas, form (forma), subforma. There are definitions of following taxonomic ranks in International Code of Nomenclature for Cultivated Plants: cultivar group, cultivar . According to Art 3.1 of the ICBN 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 ICBN explicitly mentions: primary ranks - - - form (forma) - - - - - - - subforma The rules in the ICBN apply primarily to the ranks of family and below, and only to some extent to those above the rank of family. Of the botanical names 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 (ternary name). For hybrids getting a hybrid name, the same ranks apply, preceded by "notho," with nothogenus as the highest permitted rank.

Examples The usual classifications of five representative 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 E. coli Table Notes: The ranks of higher taxa, especially intermediate ranks, are prone to revision as new information about relationships is discovered. For example, the traditional classification of primates (class Mammalia—subclass Theria—infraclass Eutheria—order Primates ) has been modified by new classifications such as McKenna and Bell (1997) (class Mammalia—subclass Theriformes—infraclass Holotheria, with Theria and Eutheria assigned lower ranks between infraclass and the order Primates). These differences arise because there are only a small number of ranks available and a large number of branching points in the fossil record. Within species further units may be recognized.

Animals may be classified into subspecies (for example, Homo sapiens sapiens, modern humans) or morphs (for example Corvus corax varius morpha leucophaeus, the Pied Raven). Plants may be classified into subspecies (for example, Pisum sativum subsp. sativum, the garden pea) or varieties (for example, Pisum sativum var. macrocarpon, snow pea), with cultivated plants getting a cultivar name (for example, Pisum sativum var. macrocarpon 'Snowbird'). Bacteria may be classified by strains (for example Escherichia coli O157:H7 , a strain that can cause food poisoning). Terminations of names 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. Rank -ad Table notes: In botany and mycology, names at the rank of family and below are based on the name of a genus, sometimes called the type genus of that taxon, with a standard ending.

For example, the rose family Rosaceae is named after the genus Rosa, with the standard ending "-aceae" for a family. Names above the rank of family are formed from a family name, or are descriptive (like Gymnospermae or Fungi ). For animals, there are standard suffixes for taxa only up to the rank of superfamily (ICZN 1999). Forming a name based on a generic name may be not straightforward. For example, the Latin "homo" has the genitive "hominis," thus the genus "Homo" (human) is in the Hominidae , not "Homidae." The ranks of epifamily, infrafamily, and infratribe (in animals) are used where the complexities of phyletic branching require finer-than-usual distinctions. Although they fall below the rank of superfamily, they are not regulated under the International Code of Zoological Nomenclature and hence do not have formal standard endings. The suffixes listed here are regular, but informal (Gaffney and Meylan 1988). Notes ↑ Bacteriologocal Code (1990 Revision) , J.P. Euzéby.

Retrieved May 2, 2008. ↑ For example, the chelonian infrafamilies Chelodd (Gaffney and Meylan 1988, 169) and Baenodd (Gaffney and Meylan 1988, 176). References Brummitt, R. K., and C. E. Powell. 1992. Authors of Plant Names. Royal Botanic Gardens, Kew. ISBN 0947643443 . Gaffney, E. S., and P. A. Meylan. 1988. A phylogeny of turtles. Pages 157-219 in M.J. Benton (ed.), The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds. Oxford: Clarendon Press. ISBN 0198577052 . International Botanical Congress (16th : 1999 : St. Louis, Mo.), W. Greuter, and J. McNeill. 2000.

International Code of Botanical Nomenclature (Saint Louis Code) Adopted by the Sixteenth International Botanical Congress, St. Louis, Missouri, July-August 1999. Prepared and Edited by W. Greuter, chairman, J. McNeill, et al.. Konigstein, Germany: Koeltz Scientific Books. ISBN 3904144227 . International Commission on Zoological Nomenclature (ICZN) and W. D. L. Ride. 1999. International Code of Zoological Nomenclature, 4th edition. London : International Trust for Zoological Nomenclature, c/o Natural History Museum. ISBN 0853010064 . McKenna, M. C., and S. K. Bell. 1997. Classification of Mammals Above the Species Level. New York, NY: Columbia University Press. ISBN 023111012X . Credits New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards .

This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here: Phylum A classic taxonomic rank above the class level and - BIO - 225 View Full Document • Phylum: A classic taxonomic rank above the class level and below the kingdom level. • Kingdom: A classic taxonomic rank above the phylum level and below the domain level. • Taxon: Any named group of species at any level of a classification system.

• Phylogeny: The evolutionary history of a group of organisms • Eukaryotes: A member of the domain Eukarya; an organism with complex cells with distinctive traits such as a nucleus, membrane-bound organelles, a cytoskeleton, and other features • Prokaryotes: A member of the domain Bacteria or Archaea; a unicellular organism lacking certain complex cell features, such as a membrane- bound nucleus and gene introns • Phylogenetic Tree: A diagram that depicts the evolutionary history of a group of organisms • Null Hypothesis: A hypothesis that specifies what the results of an experiment will be if the main hypothesis being tested is wrong.

Often states that there will be no difference between experimental groups • Control: In an experiment, a group of organisms or samples that do not receive the experimental treatment but are otherwise identical to the group that does Ch 2 Vocab • Chemical Evolution: The hypothesis that simple chemical compounds in the ancient atmosphere and ocean combined by spontaneous chemical reactions to form larger, more complex substances, eventually leading to the origin of life and the start of biological evolution • Radiometric Dating: • Electrons: • Nucleus: • Protons: • Neutrons: • Elements: • Isotopes: • Mass Number: • Atomic Mass Unit(amu): • Radioactive Isotopes: This preview has intentionally blurred sections. Sign up to view the full version. Life Science | Session 2 Taxonomic Classification How are organisms classified to the species level? A hierarchical system is used for classifying organisms to the species level. This system is called taxonomic classification. The broadest classifications are by domain and kingdom; the most specific classification is by genus and species. The hierarchical groupings in between include phylum, class, family, and order. What is a species? Species are the basic unit of classification.

While there are different views on what defines a species, in sexually reproducing organisms, a species has traditionally been defined by the ability of its members to reproduce together to form fertile offspring. This definition is trickier in asexually reproducing organisms like bacteria, archaea, and protists, where scientists look at the similarity in DNA among individuals to tell whether they are in the same “species.” When identifying an organism, familiar names — like human, fruit fly, or maple tree — are most likely the names you use. However, each type of organism has a scientific name — humans are called Homo sapiens, for example. Scientific names are derived from the genus and species names in a system known as binomial nomenclature (“bi” = two; “nom” = name). When species names appear in print, the genus is always capitalized and the species name is not, and both names appear in italics (or underlined). This system allows for a common language with which biologists can both classify and compare organisms. It also provides a basis for biologists to communicate their findings with other scientists. A key aspect of taxonomy is the ability to characterize each level of description with unifying features, thus relaying information about the organism(s).

For example, for Homo sapiens, the classification would break down as follows: Classification level A. rubrum Red maple As additional organisms are described and additional features are found which differentiate these groups, biologists have added taxonomic levels to distinguish groups from one another. As seen in the Homo sapiens table, there are “sub” and “super” groupings which come before or after the traditional taxonomic level. This further level of detail gives scientists more power to describe organisms. Not surprisingly, there are levels “below” species. Particularly common in bacteria and plants, “subspecies” are described which can produce viable offspring but possess one or more features which distinguish them from other members of that species. In plants, these sub groups are referred to as different “varieties” or “subspecies,” while in single-celled organisms, they are referred to as “strains.” Within the animal kingdom, subspecies may be termed “races” or “breeds.” For example, all domesticated dogs are grouped in the same species, Canis familiaris, though we all know there is a huge diversity of subspecies, or breeds. Ideally, the taxonomic classification reflects evolutionary relationships among organisms.

For example, it is accepted that all organisms included in the phylum Chordata descend from a common ancestor. Currently, many biologists are using DNA sequence data to verify taxonomic descriptions of organisms and determine the patterns of evolution within and between different groups.

Question: What taxonomic rank comes above phylum?
Answer: Kingdom