Habit (biology)

This cultivar of Japanese Maple has a dome-like habit.

In biology, habit has different senses according to its branches. In zoology (particularly in ethology) it usually refers to the instinctive actions of animals. In botany it refers to the form in which a given species of plant grows.^[1]

Behavior

In zoology, this term most often refers to specific behavioral characteristics, even when directly related to physiology. For example:

• The spider monkey has an arboreal habit and rarely ventures onto the forest floor.
• The brittlestar has the habit of breaking off arms as a means of defense.

Mode of life (or lifestyle, modus vivendi) is a concept related to habit. It may refer to the locomotor capabilities (motile, sessile, errant, sedentary), feeding behaviours and mechanisms, nutrition mode (free-living, parasitic, holozoic, saprotrophic, trophic type), type of habitat (terrestrial, arboreal, aquatic, marine, freshwater, seawater, benthic, pelagic, nektonic, planktonic, etc), period of activity (diurnal, nocturnal), types of ecological interaction, etc.

The habits of plants and animals can change because of changes in their environment. For example: if a species develops a disease, then the normal habits may change. Such changes may be either pathological, or adaptive.^[2]

Structure

In botany, the term is used most often to describe the general appearance, growth form, or architecture. For example:

• Many species of maple have a shrubby habit and may form bushes or hedges rather than trees.
• Certain alpine plants have been chosen for cultivation because of their dwarf habit.

Plants can be woody or herbaceous. The main types of woody plants are trees, shrubs and lianes. Climbing plants (vines) can be woody (lianas) or herbaceous (nonwoody vines). Plants can also be categorized as subshrubs (dwarf shrub, bush), cushion plants and succulents.

There is some overlap between the classifications of plants according to their habit and their life-form.

Other terms in biology refer similarly to various taxa; for example:

• Fungi are described by their growth patterns: molds, yeasts, mushrooms and dimorphic fungi.
• Lichens structure is described their growth form: foliose, crustose, fruticose or gelatinous.
• Bryophytes structure is described as foliose or thallose.
• The structure of a given species of algae is referred to as its type or level of organization.
• Bacteria are described by their morphology or shape.
• Animal structure is described by its body plan, which encompasses the body symmetry, the type of germ layers and of body cavities. Animal general appearance is termed habitus.

Since both concepts – mode of behavior and morphological form – are significant in zoology, the term habitus (from which the word habit derives) is used to describe form as distinct from behaviour (habit). The term habitus also occurs in botanical texts, but there it is used interchangeably with habit, because plant behaviour generally does not correspond closely to the concept of habits in the zoological sense.

See also

• Habitat
• Animal migration
• Habit (psychology)

References

External links

• The Columbia Encyclopedia, Sixth Edition. 2001-05
• Biology-Online.org