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]
O
- Obligate mutualism
- A condition in which a mutualistic relationship with other species is essential for a species to survive.
- Oligophagous
- Consuming a small range of types of food items.
- Omnivory
- Feeding on prey from more than one trophic level.
- Ontogenetic
- Occurring during the course of an organism's development.
- Opportunistic species
- One that is capable of exploiting spasmodically occurring environments.
- Optimal diet model
- Mathematical formulation of prey selection that would, in theory, provide the best energy returns to the consumer: used as a yardstick to assess actual performance.
- Optimum similarity
- The level of similarity between competing species, which, if either exceeded or reduced, would lead to a lowering of fitness for individuals in at least one of the species.
- Ordination
- Mathematical system for categorizing communities on a graph so that those that are most similar in species composition appear closest together.
- Osmoregulation
- Regulation of the salt concentration in cells and body fluids.
- Osmosis
- Diffusion of water across a semi-permeable membrane.
- Osmotic pressure
- The tendency of water to move across a semi-permeable membrane into a solution.
- Outbreeding
- In which genetically dissimilar organisms mate with each other.
- Overcompensating density dependence
- Density dependence which is so intense that increases in initial density lead to reductions in final density.
- Overexploitation
- Exploitation of (removal of individuals or biomass from) a natural population at a rate greater than the population is able to match with its own recruitment, thus tending to drive the population towards extinction.
- Overgrowth competition
- Competition amongst sessile organisms where the mechanism is the growth of one individual over another, preventing the efficient capture of light, suspended food or some other resource.
