Glossary
[A]
[B] [C]
[D] [E]
[F] [G]
[H] [I]
[J] [K]
[L] [M]
[N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]
[N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]
H
- Habitat
- Place where a microorganism, plant or animal lives.
- Habitat diversity
- The range of habitats present in a region.
- Halophyte
- A plant that tolerates very salty soil.
- Handling time
- The length of time a predator spends in pursuing, subduing and consuming a prey item and then preparing itself for further prey searching.
- Hardening
- A process by which the tolerance of extreme conditions, e.g. cold or drought, is increased by prior exposure to the same but less extreme conditions.
- Haustoria
- Branches of parasitic plants or fungi which enter the tissues or cells of the host.
- Hemiparasite
- Plants which are photosynthetic but form connections with the roots or stems of other plant species, drawing most or all of their water and mineral nutrient resources from their host.
- Herbicide
- A chemical or biological preparation which kills plants.
- Herbivory
- The consumption of living plant material.
- Heritable variation
- The proportion of variation in a trait due to the effects of genetic factors.
- Heterotroph
- An organism with a requirement for energy-rich organic molecules (animals, fungi and most bacteria).
- Heterotrophic succession
- A temporal succession of species at a location, principally involving animals.
- Heterozygote
- An organism carrying different alleles at the corresponding sites on homologous chromosomes.
- Hibernate
- To remain dormant during the winter period.
- Holoparasite
- Parasitic plants which lack chlorophyll and are therefore wholly dependent on their host plant for the supply of water, nutrients and fixed carbon.
- Homeostasis
- Maintenance of relatively constant internal conditions in the face of a varying external environment.
- Homeotherm
- An organism which maintains an approximately constant body temperature, usually above that of the surrounding medium.
- Homing
- To return accurately to the place of origin, e.g. the return of salmon, after migration to the sea, to the same river in which they originally hatched.
- Homologous structures
- Similarity in structure assumed to result from a common ancestry, e.g. the wing of a bird and the foreleg of a mammal.
- Homozygote
- An organism carrying identical alleles at the corresponding sites on homologous chromosomes.
- Host
- An organism which is parasitized by a parasite.
- Host density dependence
- Applied to the aggregation of risk to hosts from parasitoid attacks: hosts in either higher or lower host density patches tend to be at a greater risk of attack (direct and inverse host density dependence, respectively). Could also be applied to other predator - prey interactions. (See also Aggregation of risk and cf. Host density independence.)
- Host density independence
- Applied to the aggregation of risk to hosts from parasitoid attacks: risk varies from patch to patch but is not related to host density in a patch. Could also be applied to other predator - prey interactions. (See also Aggregation of risk and cf. Host density dependence.)
- Hydrological cycle
- The movement of water from ocean, by evaporation, to atmosphere, to land and back, via river flow, to ocean.
- Hydrophilia
- An overwhelming desire for water.
- Hydrospheric
- Pertaining to the water in soil, river, lake and ocean.
