Linnaean taxonomy classifies living things into a hierarchy, originally starting with kingdoms. Today, many biologists consider Domains to be a classification above Kingdoms. Kingdoms are divided into phyla (singular: phylum)—for animals; the term division, used for plants, is equivalent to the rank of phylum (and the current International Code of Botanical Nomenclature allows the use of either term). Phyla (or divisions) are divided into classes, and they, in turn, into orders, families, genera (singular: genus), and species (singular: species). Variety (varietas) and form (forma) are ranks below the level of subspecies that are unique to plant classification; "form" has largely fallen out of favor (although some botanists still cling to this rank), and many botanists now prefer to use "subspecies" instead of "variety" although the two are not, strictly speaking, of equivalent rank. Groups of organisms at any of these ranks are called taxa (singular: taxon), or phyla, or taxonomic groups. For the various types of hierarchy, see hierarchy (disambiguation) A hierarchy (in Greek: Ιεραρχία, it is derived from ιερός-hieros, sacred, and άρχω-arkho, rule) is a system of ranking and organizing things or people, where each element of the system (except for the top element) is subordinate to a single other element. ... In biology, a domain (also superregnum, superkingdom, or empire) is the top-level grouping of organisms in scientific classification, higher than a kingdom. ... Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (rhombozoans) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ... The International Code of Botanical Nomenclature (ICBN) is the set of rules that governs plant nomenclature, i. ...

Taxonomic ranks

A summary of this scheme, from most general to most specific, would be:

A large beetle collection

• Domain (or Superregnum) (not accepted by all biologists)
• Kingdom (or Regnum)
• Phylum (or division)
  • Subphylum
  • Superclass
• Class
  • Subclass
    • Infraclass
  • Superorder
• Order
  • Suborder
  • Superfamily
• Family
  • Subfamily
• Genus
  • Subgenus
• Species
  • Subspecies
    • Variety (plants only)
      • Form (plants only)

Download high resolution version (800x605, 164 KB) File links The following pages link to this file: Linnaean taxonomy Entomology ... Download high resolution version (800x605, 164 KB) File links The following pages link to this file: Linnaean taxonomy Entomology ... In biology, a domain (also superregnum, superkingdom, or empire) is the top-level grouping of organisms in scientific classification, higher than a kingdom. ... Ernst Haeckels presentation of a three-kingdom system (Plantae, Protista, Animalia) in his 1866 Generelle Morphologie der Organismen. ... Phylum (plural: phyla) is a taxon used in the classification of animals, adopted from the Greek phylai the clan-based voting groups in Greek city-states. ... In biology, the equivalent of a phylum in the plant or fungi kingdom is called a division. ... In biology, a subphylum is a taxonomic grade intermediate between phylum and superclass. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... In biology, a subclass is one level below a class. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... In biology, a superfamily is a taxonomic grade intermediate between suborder and family. ... Scientific classification or biological classification refers to how biologists group and categorize extinct and living species of organisms. ... ... In biology, a genus (plural genera) is a taxonomic grouping. ... In biology, a subgenus is a taxonomic grade intermediate between genus and species. ... In biology, a species is the basic unit of biodiversity. ... In zoology, as in other branches of biology, subspecies is the rank immediately subordinate to a species. ... Variety (linguistics) is a concept that includes for instance dialects, standard language and jargon. ... This article is about the meanings of the word form connected with shape or structure. ...

Example classification: humans

As an example, consider the Linnaean classification for modern humans: Trinomial name Homo sapiens sapiens Linnaeus, 1758 Humans, or human beings, are biologically classified as bipedal primates belonging to the mammalian species Homo sapiens (Latin for wise man or thinking man) under the family Hominidae (the great apes). ...

• Kingdom: Animalia (with eukaryotic cells having cell membrane but lacking cell wall, multicellular, heterotrophic)
• Phylum: Chordata (all animals with a notochord)
• Class: Mammalia (vertebrates with mammary glands that in females secrete milk to nourish young, hair, warm-blooded, bears live young)
• Order: Primates (collar bone, eyes face forward, grasping hands with fingers, two types of teeth: incisors and molars)
• Family: Hominidae (upright posture, large brain, stereoscopic vision, flat face, hands and feet have different specializations)
• Genus: Homo (s curved spine, "man")
• Species: Homo sapiens (high forehead, well-developed chin, skull bones thin)

Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (rhombozoans) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ... Multicellular organisms are those organisms containing more than one cell, and having differentiated cells that perform specialized functions. ... A heterotroph (Greek heteron = (an)other and trophe = nutrition) is an organism that requires organic substrates to get its carbon for growth and development. ... Typical Classes Subphylum Urochordata - Tunicatas Ascidiacea Thaliacea Larvacea Subphylum Cephalochordata - Lancelets Subphylum Myxini - Hagfishes Subphylum Vertebrata - Vertebrates Petromyzontida - Lampreys Placodermi (extinct) Chondrichthyes - Cartilaginous fishes Acanthodii (extinct) Actinopterygii - Ray-finned fishes Actinistia - Coelacanths Dipnoi - Lungfishes Amphibia - Amphibians Reptilia - Reptiles Aves - Birds Mammalia - Mammals Chordates (phylum Chordata) include the vertebrates, together with... The notochord is a flexible rod-shaped body found in embryos of all chordates. ... Orders Subclass Multituberculata (extinct) Plagiaulacida Cimolodonta Subclass Palaeoryctoides (extinct) Subclass Triconodonta (extinct) Subclass Eutheria (includes extinct ancestors)/Placentalia (excludes extinct ancestors) Afrosoricida Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Litopterna (extinct) Macroscelidea Mesonychia (extinct) Notoungulata (extinct) Perissodactyla Pholidota Plesiadapiformes... A glass of cow milk Milk most often means the nutrient liquid produced by the mammary glands of female mammals. ... For the ecclesiastical use of this term, see primate (religion) Families 13, See classification A primate is any member of the biological order Primates, the group that contains all lemurs, monkeys, and apes, including humans. ... Genera Subfamily Ponginae Pongo - orangutans Gigantopithecus† Sivapithecus† Lufengpithecus† Ankarapithecus† Subfamily Homininae Gorilla - gorillas Pan - chimpanzees Homo - Humans and their immediate ancestors Ouranopithecus† Paranthropus† Australopithecus† Sahelanthropus† Orrorin† Ardipithecus† Kenyanthropus† The hominids are the members of the biological family Hominidae (the great apes), which includes humans, chimpanzees, gorillas, and orangutans. ... Species Homo sapiens sapiens See text for extinct species. ... Two young girls Human beings are defined variously in biological, spiritual, and cultural terms, or in combinations thereof. ...

Nomenclature

A strength of Linnaean taxonomy is that it can be used to develop a simple and practical system for organizing the different kinds of living organisms. The greatest innovation of Linnaeus, and still the most important aspect of this system, is the general use of binomial nomenclature, the combination of a genus name and a single specific epithet ("sapiens" in the example above), to uniquely identify each species of organism. In the example, humankind is uniquely identified by the binomial Homo sapiens. No other species of animal can have this binomial. In this way, every species is given a unique and stable name (compared with common names that are often neither unique nor consistent from place to place and language to language). This uniqueness and stability are, of course, a result of the acceptance by working systematists (biologists specializing in taxonomy); not merely of the binomial nomenclature in itself, but of much more complex codes of rules and procedures governing the use of these names. In biology and ecology, an organism (in Greek organon = instrument) is a complex adaptive system of organs that influence each other in such a way that they function as a more or less stable whole and have properties of life. ... In biology, binomial nomenclature is the formal method of naming species. ...

These rules—or at least those governing the nomenclature and classification of plants and fungi—are contained in the International Code of Botanical Nomenclature, maintained by the International Association for Plant Taxonomy. The current code, the "Saint Louis Code" was adopted in 1999 and supersedes the "Tokyo code". Similar codes exist for animals and bacteria. Scientists follow these codes so that the names of organisms can be as clear and stable as possible. Nomenclature is a system of naming and categorizing objects in a given category. ... Divisions Chytridiomycota Deuteromycota Zygomycota Glomeromycota Ascomycota Basidiomycota Fungus growing on a tree in Borneo A fungus (plural fungi) is a eukaryotic organism that digests its food externally and absorbs the nutrient molecules into its cells. ... The International Code of Botanical Nomenclature (ICBN) is the set of rules that governs plant nomenclature, i. ... The International Association for Plant Taxonomy (IAPT) is devoted to plant systematics, taxonomy and nomenclature. ...

Later developments

Over time, our understanding of the relationships between living things has changed. The greatest change was the widespread acceptance of evolution as the mechanism of biological diversity and species formation. After this, it became generally understood that classifications ought to reflect the phylogeny of organisms, where each taxon should originate from a single ancestral form. Such taxa are designated as being monophyletic. In modern systems it is generally encouraged that taxa should be strictly monophyletic. A speculative phylogenetic tree of all living things, based on rRNA gene data, showing the separation of the three domains, bacteria, archaea and eukaryotes. ... In biology, phylogenetics (Greek: phylon = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e. ... In phylogenetics, a group is monophyletic (Greek: of one stem) if all organisms in that group are known to have developed from a common ancestral form, and all descendants of that form are included in the group. ...

Originally, Linnaeus established three kingdoms in his scheme, namely Plantae, Animalia and an additional group for minerals, which has since been abandoned. Since then, various life forms have been moved into three new kingdoms: Monera, for prokaryotes (i.e., bacteria); Protista, for protozoans and most algae; and Fungi. This five kingdom scheme is still far from the phylogenetic ideal and has largely been supplanted in modern taxonomic work by a division into three domains: Bacteria and Archaea, which contain the prokaryotes, and Eukaryota, comprising the remaining forms. This change was precipitated by the discovery of the Archaea. Divisions Land plants (embryophytes) Non-vascular plants (bryophytes) Marchantiophyta - liverworts Anthocerotophyta - hornworts Bryophyta - mosses Vascular plants (tracheophytes) Lycopodiophyta - clubmosses Equisetophyta - horsetails Pteridophyta - true ferns Psilotophyta - whisk ferns Ophioglossophyta - adderstongues Seed plants (spermatophytes) †Pteridospermatophyta - seed ferns Pinophyta - conifers Cycadophyta - cycads Ginkgophyta - ginkgo Gnetophyta - gnetae Magnoliophyta - flowering plants Adiantum pedatum (a fern... Phyla Subregnum Parazoa Porifera (sponges) Subregnum Agnotozoa Placozoa (trichoplax) Orthonectida (orthonectids) Rhombozoa (rhombozoans) Subregnum Eumetazoa Radiata (unranked) (radial symmetry) Ctenophora (comb jellies) Cnidaria (coral, jellyfish, anemones) Bilateria (unranked) (bilateral symmetry) Acoelomorpha (basal) Orthonectida (parasitic to flatworms, echinoderms, etc. ... Minerals are natural compounds formed through geological processes. ... A phylogenetic tree of living things, based on rRNA sequence data, showing the separation of bacteria, archaea, and eukaryotes. ... Domain Archaea - Archaebacteria Bacteria - Eubacteria Prokaryotes (from Old Greek pro- before + karyon nut or kernel, referring to the cell nucleus, + suffix -otos, pl. ... Typical phyla Rhodophyta (red algae) Chromista Heterokontophyta (heterokonts) Haptophyta Cryptophyta (cryptomonads) Alveolates Dinoflagellata Apicomplexa Ciliophora (ciliates) Excavates Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Amoebozoa Choanozoa Many others; classification varies Protists (IPA: [prəʊˌtɪst]) are a heterogeneous group of living things, comprising those eukaryotes that are neither animals, plants... Divisions Chytridiomycota Deuteromycota Zygomycota Glomeromycota Ascomycota Basidiomycota Fungus growing on a tree in Borneo A fungus (plural fungi) is a eukaryotic organism that digests its food externally and absorbs the nutrient molecules into its cells. ... In biology, phylogenetics (Greek: phylon = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e. ... Phyla/Divisions Actinobacteria Aquificae Bacteroidetes/Chlorobi Chlamydiae/Verrucomicrobia Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Nitrospirae Omnibacteria Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Bacteria (singular, bacterium) are a major group of living organisms. ... Phyla / Classes Phylum Crenarchaeota Phylum Euryarchaeota     Halobacteria     Methanobacteria     Methanococci     Methanopyri     Archaeoglobi     Thermoplasmata     Thermococci Phylum Korarchaeota Phylum Nanoarchaeota The Archaea (IPA: ), also called Archaebacteria (IPA: ), are a major division of living organisms. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Protista A eukaryote (also spelled eucaryote) is an organism with complex cells, in which the genetic material is organized into membrane-bound nuclei. ... Phyla / Classes Phylum Crenarchaeota Phylum Euryarchaeota     Halobacteria     Methanobacteria     Methanococci     Methanopyri     Archaeoglobi     Thermoplasmata     Thermococci Phylum Korarchaeota Phylum Nanoarchaeota The Archaea (IPA: ), also called Archaebacteria (IPA: ), are a major division of living organisms. ...

Reflecting truly evolutionary relationships, especially given the wide acceptance of cladistic methodology and numerous molecular phylogenies that have challenged long-accepted classifications, has proven problematic within the framework of Linnaean taxonomy, and some systematists have proposed a Phylocode to replace it. Greek clados = branch) or phylogenetic systematics is a branch of biology that determines the evolutionary relationships of living things based on derived similarities. ... Types of clade PhyloCode is a draft for a formal set of rules governing phylogenetic nomenclature. ...

See also: Evolutionary tree, which has further subdivisions and presents the most current taxonomic viewpoint. The evolutionary tree of living things is currently supposed to run something along the lines of that listed below. ...

Quotations

• "Taxonomy (the science of classification) is often undervalued as a glorified form of filing—with each species in its prescribed place in an album; but taxonomy is a fundamental and dynamic science, dedicated to exploring the causes of relationships and similarities among organisms. Classifications are theories about the basis of natural order, not dull catalogues compiled only to avoid chaos." Stephen Jay Gould (1990, p.98)

This article is in need of attention. ...

References

• Gould, S.J. (1990), Wonderful Life: The Burgess Shale and the Nature of History. Hutchinson Radius.
• Dawkins, Richard The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution. Houghton Mifflin.

Wonderful Life is a book on evolution by Stephen Jay Gould. ... The Ancestors Tale: A Pilgrimage to the Dawn of Life is a popular science book by Professor Richard Dawkins, with contributions from Dawkins research assistant Yan Wong. ...

External links

• Wikispecies
• International Code of Botanical Nomenclature (Saint Louis Code), Electronic version
• Tree of Life