zoology Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the animal kingdom, including the structure, embryology, evolution, classification, habits, and ...

, 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 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 ...

'' 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.

Usage of the term

Some zoologists use the word "form" or "forma" to describe variation in animals, especially

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three ...

s, as part of a series of terms and abbreviations that are appended to the binomen or

trinomen 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. In zoology In zoological nomenclature, a trinomen (), trinominal name, or ternary ...

. 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

cline Cline may refer to: Science * Cline (biology), a measurable gradient in a single trait in a species across its geographical range * Cline (hydrology), a fluid layer with a property that varies * Cline (mathematics) or generalised circle, a circl ...

s. As opposed to morphs (see below), a

subpopulation In statistics, a population is a Set (mathematics), set of similar items or events which is of interest for some question or experiment. A statistical population can be a group of existing objects (e.g. the set of all stars within the Milky Way g ...

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

; 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 Small populations can behave differently from larger populations. They are often the result of population bottlenecks from larger populations, leading to loss of heterozygosity and reduced genetic diversity and loss or fixation of alleles and s ...

. ''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,

albino Albinism is the congenital absence of melanin in an animal or plant resulting in white hair, feathers, scales and skin and pink or blue eyes. Individuals with the condition are referred to as albino. Varied use and interpretation of the term ...

s). : 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: * A morph is a similar concept with a less restricted occurrence (''see also'' Polymorphism). As neither forms nor morphs are officially recognised terminology in zoology, application can vary but, generally, morphs occur without geographical or seasonal restriction, and may constitute a significant part of the population; usually, several morphs co-occur in a single

at a given time. The

peppered moth The peppered moth (''Biston betularia'') is a temperate species of night-flying moth. It is mostly found in the northern hemisphere in places like Asia, Europe and North America. Peppered moth evolution is an example of population genetics an ...

is a famous example. * Botanical nomenclature is much more complex, with the use of

varieties Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

, subvarieties, and

forms Form is the shape, visual appearance, or configuration of an object. In a wider sense, the form is the way something happens. Form also refers to: *Form (document), a document (printed or electronic) with spaces in which to write or enter data * ...

being formally regulated by the ''

ICBN The ''International Code of Nomenclature for algae, fungi, and plants'' (ICN) is the set of rules and recommendations dealing with the formal botanical names that are given to plants, fungi and a few other groups of organisms, all those "trad ...

''.

References

{{reflist Zoological nomenclature Forma taxa