In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralize the defining features of that particular taxon. In older usage (pre-1900 in botany), a type was a taxon rather than a specimen.
A taxon is a scientifically named grouping of organisms with other like organisms, a set that includes some organisms and excludes others, based on a detailed published description (for example a species description) and on the provision of type material, which is usually available to scientists for examination in a major museum research collection, or similar institution.
According to a precise set of rules laid down in the International Code of Zoological Nomenclature (ICZN) and the International Code of Nomenclature for algae, fungi, and plants (ICN), the scientific name of every taxon is almost always based on one particular specimen, or in some cases specimens. Types are of great significance to biologists, especially to taxonomists. Types are usually physical specimens that are kept in a museum or herbarium research collection, but failing that, an image of an individual of that taxon has sometimes been designated as a type. Describing species and appointing type specimens is part of scientific nomenclature and alpha taxonomy.
When identifying material, a scientist attempts to apply a taxon name to a specimen or group of specimens based on his or her understanding of the relevant taxa, based on (at least) having read the type description(s), preferably based on an examination of all the type material of all of the relevant taxa. If there is more than one named type that all appear to be the same taxon, then the oldest name takes precedence, and is considered to be the correct name of the material in hand. If on the other hand the taxon appears never to have been named at all, then the scientist or another qualified expert picks a type specimen and publishes a new name and an official description.
This process is crucial to the science of biological taxonomy. People's ideas of how living things should be grouped change and shift over time. How do we know that what we call "Canis lupus" is the same thing, or approximately the same thing, as what they will be calling "Canis lupus" in 200 years' time? It is possible to check this because there is a particular wolf specimen preserved in Sweden and everyone who uses that name – no matter what else they may mean by it – will include that particular specimen.
Depending on the nomenclature code applied to the organism in question, a type can be a specimen, a culture, an illustration, or (under the bacteriological code) a description. Some codes consider a subordinate taxon to be the type, but under the botanical code the type is always a specimen or illustration.
For example, in the research collection of the Natural History Museum in London, there is a bird specimen numbered 18126.96.36.199. This is a specimen of a kind of bird commonly known as the spotted harrier, which currently bears the scientific name Circus assimilis. This particular specimen is the holotype for that species; the name Circus assimilis refers, by definition, to the species of that particular specimen. That species was named and described by Jardine and Selby in 1828, and the holotype was placed in the museum collection so that other scientists might refer to it as necessary.
Note that at least for type specimens there is no requirement for a "typical" individual to be used. Genera and families, particularly those established by early taxonomists, tend to be named after species that are more "typical" for them, but here too this is not always the case and due to changes in systematics cannot be. Hence, the term name-bearing type or onomatophore is sometimes used, to denote the fact that biological types do not define "typical" individuals or taxa, but rather fix a scientific name to a specific operational taxonomic unit. Type specimens are theoretically even allowed to be aberrant or deformed individuals or color variations, though this is rarely chosen to be the case, as it makes it hard to determine to which population the individual belonged.
In some older taxonomic works the word "type" has sometimes been used differently. The meaning was similar in the first Laws of Botanical Nomenclature, but has a meaning closer to the term taxon in some other works:
Ce seul caractère permet de distinguer ce type de toutes les autres espèces de la section. … Après avoir étudié ces diverses formes, j'en arrivai à les considérer comme appartenant à un seul et même type spécifique.
Translation: This single character permits [one to] distinguish this type from all other species of the section ... After studying the diverse forms, I came to consider them as belonging to the one and the same specific type.
In botanical nomenclature, a type (typus, nomenclatural type), "is that element to which the name of a taxon is permanently attached." (article 7.1) In botany a type is either a specimen or an illustration. A specimen is a real plant (or one or more parts of a plant or a lot of small plants), dead and kept safe, "curated", in a herbarium (or the equivalent for fungi). Examples of where an illustration may serve as a type include:
Note that a type does not determine the circumscription of the taxon. For example, the common dandelion is a controversial taxon: some botanists consider it to consist of over a hundred species, and others regard it as a single species. The type of the name Taraxacum officinale is the same whether the circumscription of the species includes all those small species (Taraxacum officinale is a "big" species) or whether the circumscription is limited to only one small species among the other hundred (Taraxacum officinale is a "small" species). The name Taraxacum officinale is the same and the type of the name is the same, but the extent of what the name actually applies to varies greatly. Setting the circumscription of a taxon is done by a taxonomist in a publication.
The ICN provides a listing of the various kinds of type (article 9 and the Glossary), the most important of which is the holotype. These are
Note that the word "type" appears in botanical literature as a part of some older terms that have no status under the ICN: for example a clonotype.
In zoological nomenclature, the type of a species or subspecies is a specimen, or series of specimens. The type of a genus or subgenus is a species. The type of a suprageneric taxon (e.g., family, etc.) is a genus. Names higher than superfamily rank do not have types. A "name-bearing type" is a specimen or image that "provides the objective standard of reference whereby the application of the name of a nominal taxon can be determined."
Although in reality biologists may examine many specimens (when available) of a new taxon before writing an official published species description, nonetheless, under the formal rules for naming species (the International Code of Zoological Nomenclature), a single type must be designated, as part of the published description.
A type description must include a diagnosis (typically, a discussion of similarities to and differences from closely related species), and an indication of where the type specimen or specimens are deposited for examination. The geographical location where a type specimen was originally found is known as its type locality. In the case of parasites, the term type host (or symbiotype) is used to indicate the host organism from which the type specimen was obtained.
Zoological collections are maintained by universities and museums. Ensuring that types are kept in good condition and made available for examination by taxonomists are two important functions of such collections. And, while there is only one holotype designated, there can be other "type" specimens, the following of which are formally defined:
When a single specimen is clearly designated in the original description, this specimen is known as the holotype of that species. The holotype is typically placed in a major museum, or similar well-known public collection, so that it is freely available for later examination by other biologists.
When the original description designated a holotype, there may still be additional specimens listed in the type series and those are termed paratypes. These are not name-bearing types.
An allotype is a specimen of the opposite sex to the holotype, designated from among paratypes. It was also formerly used for a specimen that shows features not seen in the holotype of a fossil. The term is not regulated by the ICZN.
A neotype is a specimen later selected to serve as the single type specimen when an original holotype has been lost or destroyed or where the original author never cited a specimen.
A syntype is any one of two or more specimens that is listed in a species description where no holotype was designated; historically, syntypes were often explicitly designated as such, and under the present ICZN this is a requirement, but modern attempts to publish species description based on syntypes are generally frowned upon by practicing taxonomists, and most are gradually being replaced by lectotypes. Those that still exist are still considered name-bearing types.
A lectotype is a specimen later selected to serve as the single type specimen for species originally described from a set of syntypes. In zoology, a lectotype is a kind of name-bearing type. When a species was originally described on the basis of a name-bearing type consisting of multiple specimens, one of those may be designated as the lectotype. Having a single name-bearing type reduces the potential for confusion, especially considering that it is not uncommon for a series of syntypes to contain specimens of more than one species.
A paralectotype is any additional specimen from among a set of syntypes, after a lectotype has been designated from among them. These are not name-bearing types.
A special case in Protistans where the type consists of two or more specimens of "directly related individuals representing distinct stages in the life cycle"; these are collectively treated as a single entity, and lectotypes cannot be designated from among them.
An illustration on which a new species or subspecies was based. For instance, the Burmese python, Python bivittatus, is one of many species that are based on illustrations by Albertus Seba (1734).
Recently, some species have been described where the type specimen was released alive back into the wild, such as the Bulo Burti boubou (a bushshrike), described as Laniarius liberatus, in which the species description included DNA sequences from blood and feather samples. Assuming there is no future question as to the status of such a species, the absence of a type specimen does not invalidate the name, but it may be necessary in the future to designate a neotype for such a taxon, should any questions arise. However, in the case of the bushshrike, ornithologists have argued that the specimen was a rare and hitherto unknown color morph of a long-known species, using only the available blood and feather samples. While there is still some debate on the need to deposit actual killed individuals as type specimens, it can be observed that given proper vouchering and storage, tissue samples can be just as valuable should disputes about the validity of a species arise.
The various types listed above are necessary because many species were described one or two centuries ago, when a single type specimen, a holotype, was often not designated. Also, types were not always carefully preserved, and intervening events such as wars and fires have resulted in destruction of original type material. The validity of a species name often rests upon the availability of original type specimens; or, if the type cannot be found, or one has never existed, upon the clarity of the description.
The ICZN has existed only since 1961, when the first edition of the Code was published. The ICZN does not always demand a type specimen for the historical validity of a species, and many "type-less" species do exist. The current edition of the Code, Article 75.3, prohibits the designation of a neotype unless there is "an exceptional need" for "clarifying the taxonomic status" of a species (Article 75.2).
There are many other permutations and variations on terms using the suffix "-type" (e.g., allotype, cotype, topotype, generitype, isotype, isoneotype, isolectotype, etc.) but these are not formally regulated by the Code, and a great many are obsolete and/or idiosyncratic. However, some of these categories can potentially apply to genuine type specimens, such as a neotype; e.g., isotypic/topotypic specimens are preferred to other specimens, when they are available at the time a neotype is chosen (because they are from the same time and/or place as the original type).
The term fixation is used by the Code for the declaration of a name-bearing type, whether by original or subsequent designation.
Each genus must have a designated type species (the term "genotype" was once used for this but has been abandoned because the word has become much better known as the term for a different concept in genetics). The description of a genus is usually based primarily on its type species, modified and expanded by the features of other included species. The generic name is permanently associated with the name-bearing type of its type species.
Ideally, a type species best exemplifies the essential characteristics of the genus to which it belongs, but this is subjective and, ultimately, technically irrelevant, as it is not a requirement of the Code. If the type species proves, upon closer examination, to belong to a pre-existing genus (a common occurrence), then all of the constituent species must be either moved into the pre-existing genus, or disassociated from the original type species and given a new generic name; the old generic name passes into synonymy and is abandoned unless there is a pressing need to make an exception (decided case-by-case, via petition to the International Commission on Zoological Nomenclature).
A type genus is that genus from which the name of a family or subfamily is formed. As with type species, the type genus is not necessarily the most representative, but is usually the earliest described, largest or best known genus. It is not uncommon for the name of a family to be based upon the name of a type genus that has passed into synonymy; the family name does not need to be changed in such a situation.
Allotype can refer to:
In zoological nomenclature, a designated paratype that is a specimen of the opposite sex to the holotype
In biology, a variant protein sequence that is genetically determined, particularly:
in immunology, an immunoglobulin allotypeArchetype
The concept of an archetype appears in areas relating to behavior, historical psychological theory, and literary analysis.
An archetype can be:
a statement, pattern of behavior, a prototype, a first form or a main model which other statements, patterns of behavior, and objects copy, emulate or "merge" into. (Frequently used informal synonyms for this usage include "standard example", "basic example", and the longer form "archetypal example". Mathematical archetypes often appear as "canonical examples".)
a Platonic philosophical idea referring to pure forms which embody the fundamental characteristics of a thing in Platonism
a collectively-inherited unconscious idea, pattern of thought, image, etc., that is universally present, in individual psyches, as in Jungian psychology
a constantly recurring symbol or motif in literature, painting, or mythology (this usage of the term draws from both comparative anthropology and from Jungian archetypal theory). In various seemingly unrelated cases in classic storytelling, media, etc., characters or ideas sharing similar traits recur.Archetypes are also very close analogies to instincts in the sense that it is impersonal and inherited traits that present and motivate human behavior long before any consciousness develops. They also continue to influence feelings and behavior even after some degree of consciousness developed later on.Archetypes are mostly related to linear thinking in it's creation process, but can be; from a philosophical point of view a non-linear process. Albert Einstein's; everything is relative opens for this idea as a concept of creation.Biology (song)
"Biology" is a song performed by British-Irish all-female pop group Girls Aloud, taken from their third studio album Chemistry (2005). The song was written by Miranda Cooper, Brian Higgins and Higgins' production team Xenomania, and produced by Higgins and Xenomania. Composed of distinct sections, it avoids the verse-chorus form present in most contemporary pop music. "Biology" was released as a single in November 2005, ahead of the album's release. Following the disappointment of "Long Hot Summer", "Biology" returned Girls Aloud to the top five of the UK Singles Chart and became their tenth top ten hit.
The music video, consisting only of group shots, witnesses Girls Aloud seamlessly move through various sequences while performing disjointed choreography. "Biology" was promoted through a number of live appearances and has since been performed on all of Girls Aloud's subsequent concert tours. The song, which includes a variety of styles, received widespread acclaim from contemporary music critics. Considered Girls Aloud's signature song, The Guardian referred to "Biology" as "the best pop single of the last decade".Holotype
A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several such, but explicitly designated as the holotype. Under the International Code of Zoological Nomenclature (ICZN), a holotype is one of several kinds of name-bearing types. In the International Code of Nomenclature for algae, fungi, and plants (ICN) and ICZN the definitions of types are similar in intent but not identical in terminology or underlying concept.
For example, the holotype for the butterfly Lycaeides idas longinus is a preserved specimen of that species, held by the Museum of Comparative Zoology at Harvard University. An isotype is a duplicate of the holotype and is often made for plants, where holotype and isotypes are often pieces from the same individual plant or samples from the same gathering.
A holotype is not necessarily "typical" of that taxon, although ideally it should be. Sometimes just a fragment of an organism is the holotype, particularly in the case of a fossil. For example, the holotype of Pelorosaurus humerocristatus (Duriatitan), a large herbivorous dinosaur from the early Jurassic period, is a fossil leg bone stored at the Natural History Museum in London. Even if a better specimen is subsequently found, the holotype is not superseded.Isalaux
Isalaux is a trilobite in the order Phacopida (family Pterygometopidae), that existed during the upper Ordovician in what is now the United States. It was described by Frederickson and Pollack in 1952, and the type species is Isalaux canonensis. The type locality was the Harding Formation in Colorado.Niebla dilatata
Niebla dilatata is a fruticose lichen that grows on rocks on Guadalupe Island and the foggy coast of the Baja California peninsula. The epithet, dilatata, is in reference to the broadly expanded (dilated) lobes of the thallus.Niebla dissecta
Niebla dissecta is a fruticose lichen that grows on rocks along the Pacific Coast of California, in San Mateo County and in the Channel Islands. The epithet, dissecta is in reference to the thallus repeatedly divided into branches.Niebla fimbriata
Niebla fimbriata is a fruticose lichen that grows on volcanic rocks in the Channel Islands of California and along the foggy Pacific Coast of Baja California from near San Antonio del Mar south to Arroyo Sauces, which is located south of Punta Canoas. The epithet, fimbriata is in reference to the fringed branches of the thallus.Niebla halei
Niebla halei is a fruticose lichen that grows on rocks along the foggy Pacific Coast of northern California on San Bruno Mountain The epithet, halei is in honor of Mason Hale who encouraged taxonomic revision of the genus Niebla.Niebla isidiaescens
Niebla isidiaescens is a species of fruticose lichen in the family Ramalinaceae. It was originally described in 1994 from specimens collected in Baja California. The lichen grows on rocky outcrops in open maritime scrub habitats.Niebla rugosa
Niebla rugosa is a fruticose lichen that grows on rocks along the foggy Pacific Coast of Baja California in the Vizcaíno Desert. The epithet, rugosa is in reference to the wrinkled reticulated surface of the thallus.Outline of evolution
The following outline is provided as an overview of and topical guide to evolution:
Evolution – change in heritable traits of biological organisms over generations due to natural selection, mutation, gene flow, and genetic drift. Also known as descent with modification. Over time these evolutionary processes lead to formation of new species (speciation), changes within lineages (anagenesis), and loss of species (extinction). "Evolution" is also another name for evolutionary biology, the subfield of biology concerned with studying evolutionary processes that produced the diversity of life on Earth.Principle of Typification
In biological nomenclature, the Principle of Typification is one of the guiding principles.The International Code of Zoological Nomenclature provides that any named taxon in the family group, genus group, or species group have a name-bearing type which allows the name of the taxon to be objectively applied. The type does not define the taxon: that is done by a taxonomist; and an indefinite number of competing definitions can exist side by sided . Rather, a type is a point of reference. A name has a type, and a taxonomist (having defined the taxon) can determine which existing types fall within the scope of the taxon. He or she can then use the rules in the Code to determine the valid name for the taxon.Syntype
In biological nomenclature, a syntype is any one of two or more biological types that is listed in a description of a taxon where no holotype was designated. Precise definitions of this and related terms for types have been established as part of the International Code of Zoological Nomenclature and the International Code of Nomenclature for algae, fungi, and plants.Taxonomy (biology)
In biology, taxonomy (from Ancient Greek τάξις (taxis), meaning 'arrangement', and -νομία (-nomia), meaning 'method') is the science of naming, defining (circumscribing) and classifying groups of biological organisms on the basis of shared characteristics. Organisms are grouped together into taxa (singular: taxon) and these groups are given a taxonomic rank; groups of a given rank can be aggregated to form a super-group of higher rank, thus creating a taxonomic hierarchy. The principal ranks in modern use are domain, kingdom, phylum (division is sometimes used in botany in place of phylum), class, order, family, genus, and species. The Swedish botanist Carl Linnaeus is regarded as the founder of the current system of taxonomy, as he developed a system known as Linnaean taxonomy for categorizing organisms and binomial nomenclature for naming organisms.
With the advent of such fields of study as phylogenetics, cladistics, and systematics, the Linnaean system has progressed to a system of modern biological classification based on the evolutionary relationships between organisms, both living and extinct.Type genus
In biological classification, especially zoology, the type genus is the genus which defines a biological family and the root of the family name.Vermilacinia howei
Vermilacinia howei is a fruticose lichen that grows on trees and shrubs in the fog regions along the Pacific Coast of North America in the coastal scrub region of the Channel Islands of California, and around Bahía de San Quintín, Baja California and further south in the Vizcaíno Desert. The epithet is in honor of Reginald Heber Howe, Jr. for his contributions to lichenology, especially acknowledged for providing images of the type (biology) specimens in his revision of the genus Ramalina.Vermilacinia leopardina
Vermilacinia leopardina is a fruticose lichen usually that grows abundantly on the branches of shrubs in the fog regions along the Pacific Coast of North America, in the Channel Islands and on the mainland of California from Santa Barbara County south to the Vizcaíno Peninsula of Baja California. The species is also reported to occur in Chile, based on a single specimen mounted on a large index card off to one corner with the type (biology) of Usnea tumidula (variant of V. ceruchis) in the center and bottom (plate 45.2 in Spjut 1996); it is possible that the specimen of V. leopardina was from North America and placed on the card for the purpose of making a comparison to the type for Usnea tumidula, which was annotated Ramalina ceruchis var. gracilior Muell.Arg., a name of uncertain status. The epithet, leopardina, is in reference to the black transverse bands and irregularly shaped black spots commonly seen on the thallus branches that obviously imply a similarity to the leopard animal, while also making comparative distinctions to other black banded species: V. tigrina and V. zebrina, obviously to a tiger and zebra, and to V. leonis, obviously a lion, which has no black stripes.