Form (zoology)

Last updated

In zoology, the word "form" or forma (literally Latin for form) is a strictly informal term that is sometimes used to describe organisms. Under the International Code of Zoological Nomenclature the term has no standing (it is not accepted). In other words, although form names are Latin, and are sometimes wrongly appended to a binomial name, in a zoological context, forms have no taxonomic significance at all.[ citation needed ]

Contents

Usage of the term

Some zoologists use the word "form" or "forma" to describe variation in animals, especially insects, as part of a series of terms and abbreviations that are appended to the binomen or trinomen. Many 'typical specimens' may be described, but none should be considered absolute, unconditional or categorical. Forms have no official status, though they are sometimes useful in describing altitudinal or geographical clines. As opposed to morphs (see below), a subpopulation usually consists of a single form only at any given point of time.

forma geographica - f. geogr.

If used, nowadays usually denotes a part of a cline; for example for intergrades between subspecies in their area of contact.

forma localis - f. loc.

As "f. geogr." but only local, more restricted in occurrence. See also small population size.

forma alta - f. alt.

Altitudinal features are not necessarily inherited, but may entirely be due to environment. The same applies to temperature or humidity-generated forms, such as:
forma vernalis - f. vern. (spring form)
forma aestivalis - f. aest. (summer form)
forma autumnalis - f. autumn. (autumn form)

aberratio - ab.

May be used for a single individual, for a small group such as an individual and its offspring, or for atypical individuals (for example, albinos).
Also used for commonly observed forms of a species, but in this case use of forma (f.) or morpha, accompanied by a descriptive name, is more conventional.

Notes:

See also

Related Research Articles

Linnaean taxonomy A rank based classification system for organisms

Linnaean taxonomy can mean either of two related concepts:

  1. the particular form of biological classification (taxonomy) set up by Carl Linnaeus, as set forth in his Systema Naturae (1735) and subsequent works. In the taxonomy of Linnaeus there are three kingdoms, divided into classes, and they, in turn, into orders, genera, and species, with an additional rank lower than species.
  2. a term for rank-based classification of organisms, in general. That is, taxonomy in the traditional sense of the word: rank-based scientific classification. This term is especially used as opposed to cladistic systematics, which groups organisms into clades. It is attributed to Linnaeus, although he neither invented the concept of ranked classification nor gave it its present form. In fact, it does not have an exact present form, as "Linnaean taxonomy" as such does not really exist: it is a collective (abstracting) term for what actually are several separate fields, which use similar approaches.
Binomial nomenclature System of identifying species of organisms using a two-part name

Binomial nomenclature, also called binominal nomenclature or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, both of which use Latin grammatical forms, although they can be based on words from other languages. Such a name is called a binomial name, a binomen, binominal name or a scientific name; more informally it is also called a Latin name.

The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the International Commission on Zoological Nomenclature. The rules principally regulate:

Subspecies Taxonomic rank subordinate to species

In biological classification, the term subspecies refers to one of two or more populations of a species living in different subdivisions of the species' range and varying from one another by morphological characteristics. A single subspecies cannot be recognized independently: a species is either recognized as having no subspecies at all or at least two, including any that are extinct. The term may be abbreviated to subsp. or ssp. The plural is the same as the singular: subspecies.

In botanical nomenclature, variety is a taxonomic rank below that of species and subspecies, but above that of form. As such, it gets a three-part infraspecific name. It is sometimes recommended that the subspecies rank should be used to recognize geographic distinctiveness, whereas the variety rank is appropriate if the taxon is seen throughout the geographic range of the species.

Holotype The example of an organism used to describe its species

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example 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.

In biology, trinomial nomenclature refers to names for taxa below the rank of species. These names have three parts. The usage is different in zoology and botany.

Type (biology) Specimen(s) to which a scientific name is formally attached

In biology, a type is a particular specimen 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, a type was a taxon rather than a specimen.

Form (botany) one of the secondary taxonomic ranks, below that of variety, in botanical nomenclature

In botanical nomenclature, a form is one of the "secondary" taxonomic ranks, below that of variety, which in turn is below that of species; it is an infraspecific taxon. If more than three ranks are listed in describing a taxon, the "classification" is being specified, but only three parts make up the "name" of the taxon: a genus name, a specific epithet, and an infraspecific epithet.

Ecotype

In evolutionary ecology, an ecotype, sometimes called ecospecies, describes a genetically distinct geographic variety, population or race within a species, which is genotypically adapted to specific environmental conditions.

Numeral or number prefixes are prefixes derived from numerals or occasionally other numbers. In English and other European languages, they are used to coin numerous series of words, such as:

unicycle – bicycle – tricycle, dyad – triad – decade, biped – quadruped, September – October – November – December, decimal – hexadecimal, sexagenarian – octogenarian, centipede – millipede, etc.

NatureServe conservation status conservation status assigned by the NatureServe

The NatureServe conservation status system, maintained and presented by NatureServe in cooperation with the Natural Heritage Network, was developed in the United States in the 1980s by The Nature Conservancy (TNC) as a means for ranking or categorizing the relative imperilment of species of plants, animals, or other organisms, as well as natural ecological communities, on the global, national and/or subnational levels. These designations are also referred to as NatureServe ranks, NatureServe statuses, or Natural Heritage ranks. While the Nature Conservancy is no longer substantially involved in the maintenance of these ranks, the name TNC ranks is still sometimes encountered for them.

Race (biology) informal rank in the taxonomic hierarchy, below the level of subspecies

In biological taxonomy, race is an informal rank in the taxonomic hierarchy, below the level of subspecies. It has been used as a higher rank than strain, with several strains making up one race. Various definitions exist. Races may be genetically distinct populations of individuals within the same species, or they may be defined in other ways, e.g. geographically, or physiologically. Genetic isolation between races is not complete, but genetic differences may have accumulated that are not (yet) sufficient to separate species. The term is recognized by some, but not governed by any of the formal codes of biological nomenclature.

In botany, an infraspecific name is the scientific name for any taxon below the rank of species, i.e. an infraspecific taxon. The scientific names of botanical taxa are regulated by the International Code of Nomenclature for algae, fungi, and plants (ICN). This specifies a 'three part name' for infraspecific taxa, plus a 'connecting term' to indicate the rank of the name. An example of such a name is Astrophytum myriostigma subvar. glabrum, the name of a subvariety of the species Astrophytum myriostigma.

A Group is a formal category in the International Code of Nomenclature for Cultivated Plants (ICNCP) used for cultivated plants (cultivars) that share a defined characteristic. It is represented in a botanical name by the symbol Group or Gp. "Group" or "Gp" is always written with a capital G in a botanical name, or epithet. The Group is not italicized in a plant's name. The ICNCP introduced the term and symbol "Group" in 2004, as a replacement for the lengthy and hyphenated "cultivar-group", which had previously been the category's name since 1969. For the old name "cultivar-group", the non-standard abbreviation cv. group or cv. Group is also sometimes encountered. There is a slight difference in meaning, since a cultivar-group was defined to comprise cultivars, whereas a Group may include individual plants.

In zoological nomenclature, author citation refers to listing the person who first makes a scientific name of a taxon available. This is done in a scientific publication while fulfilling the formal requirements under the International Code of Zoological Nomenclature, hereinafter termed "the Code". According to the Code, "the name of the author does not form part of the name of a taxon and its citation is optional, although customary and often advisable", however Recommendation 51A suggests: "The original author and date of a name should be cited at least once in each work dealing with the taxon denoted by that name. This is especially important in distinguishing between homonyms and in identifying species-group names which are not in their original combinations". For the purpose of information retrieval, the author citation and year appended to the scientific name, e.g. genus-species-author-year, genus-author-year, family-author-year, etc., is often considered a "de facto" unique identifier, although for a number of reasons discussed below, this usage may often be imperfect.

In botanical nomenclature, author citation refers to citing the person or group of people who validly published a botanical name, i.e. who first published the name while fulfilling the formal requirements as specified by the International Code of Nomenclature for algae, fungi, and plants (ICN). In cases where a species is no longer in its original generic placement, both the author(s) of the original genus placement and those of the new combination are given.

Forma specialis, abbreviated f. sp. without italics, is an informal taxonomic grouping allowed by the International Code of Nomenclature for algae, fungi, and plants, that is applied to a parasite which is adapted to a specific host. This classification may be applied by authors who do not feel that a subspecies or variety name is appropriate, and it is therefore not necessary to specify morphological differences that distinguish this form. The literal meaning of the term is 'special form', but this grouping does not correspond to the more formal botanical use of the taxonomic rank of forma or form.

Taxonomic rank Level in a taxonomic hierarchy

In biological classification, taxonomic rank is the relative level of a group of organisms in a taxonomic hierarchy. Examples of taxonomic ranks are species, genus, family, order, class, phylum, kingdom, domain, etc.

This is a list of terms and symbols used in scientific names for organisms, and in describing the names. For proper parts of the names themselves, see glossary of scientific names. Note that many of the abbreviations are used with or without a stop.

References