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 Int ...

'' 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 taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

, 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 pairs ...

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

binomen In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

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 ternar ...

. 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 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 ...

. ''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 Polymorphism, polymorphic, polymorph, polymorphous, or polymorphy may refer to: Computing * Polymorphism (computer science), the ability in programming to present the same programming interface for differing underlying forms * Ad hoc polymorphis ...

). 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 subpopulation at a given time. The peppered moth is a famous example. *

Botanical nomenclature Botanical nomenclature is the formal, scientific naming of plants. It is related to, but distinct from taxonomy. Plant taxonomy is concerned with grouping and classifying plants; botanical nomenclature then provides names for the results of this ...

is much more complex, with the use of varieties,

subvarieties Algebraic varieties are the central objects of study in algebraic geometry, a sub-field of mathematics. Classically, an algebraic variety is defined as the set of solutions of a system of polynomial equations over the real or complex numbers. Mo ...

, and forms 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