Glossary: H

Home range

The area over which an animal or group of animals normally travels to access food, mates, or shelter. Home ranges often overlap substantially with the home ranges of other individuals and they are not defended, as are territories.

habitat

The natural characteristics of the area where an organism lives; the particular location where an organism normally lives.

hallux

The single, backwards pointing toe possessed by many birds

haul out

Referring to an animal such as a seal pulling itself ashore.

heath

An area dominated by low-growing shrubs with woody stems and narrow leaves (e.g. heather), which often predominate on acidic or upland soils.

hectocotylus

the arm of a male cephalopod (Phylum Mollusca, Class Cephalopoda, including squid, cuttlefish, and octopi) which is used to transfer a spermatophore into a female's mantle chamber. This arm is specialized as an intromittent organ.

helper

An animal, usually without young of its own, which contributes to the survival of the offspring of others by behaving parentally towards the offspring.

hemimetaboly

Metamorphosis in which the organism grows by continual molting to change from a young nymph into an adult without a pupal stage. Synapomorphy of the Pterygota.

hemocoel

the primary body cavity of most invertebrates, containing circulatory fluid.

herbaceous

Referring to a plant that has little or no woody tissue and usually persists for a single growing season.

herbivore

An animal that eats mainly plants or parts of plants.

hermaphroditic

an animal which possesses both male and female functioning sex organs and can, therefore, mate both as a male or as a female. Common in invertebrates but rare in vertebrates.

heteronomy

Having segments that differ in function and appearance. Synapomorphy of the Insecta, convergent in the Branchiopoda+Maxillopoda+Malocostraca.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

heterozygosity - average

Sum the number of heterozygous individuals for each gene, divide this by the total number of individuals in the sample, and average over all genes.

heterozygous

Referring to an individual in which the alleles of a given gene are different.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

holarctic

a distribution that more or less circles the Arctic, so occurring in both the Nearctic and Palearctic biogeographic regions.

World Map

Found in northern North America and northern Europe or Asia.

holoblastic

a pattern of egg cleavage in early development in which the entire egg is divided with each cell division. Contrast to meroblastic cleavage.

holometaboly

Complete metamorphosis during development, from a growing larvae to a differentiating pupa to a reproducing adult. Synapomorphy of the Holometabola.

home range

The area in which an animal normally lives, whether or not it defends the area from other animals; the area that an animal learns thoroughly and habitually patrols.

homeotherm

see homoiotherm

homeothermic

animals that regulate their body temperature independently of ambient temperature fluctuations.

See Also: heterothermic
homoiothermic

having a body temperature that is maintained at a relatively constant level and is typically higher than the surroundings

host

an organism that provides food or shelter for another organism; often refers to parasitic relationships.

humerus

Upper (proximal) bone in the forelimb of tetrapods. Synapomorphy of the Tetrapoda+Eusthenopteron.

hybrid

The offspring of parents of different species.

hygrophilous

Living or growing in moist places.