| A | B |
|---|
| ecology | the study of relationships between different organisms and their environment |
| population | all the members of one species in a given area |
| community | the collection of the members of the different species in a given area |
| species | a group of similar individuals able to reproduce fertile offspring |
| niche | an organisms specific role and position in an ecosystem; includes feeding and living habits |
| symbiosis | a relationship between two species of organisms where at least one species benefits |
| mutualism | a symbiotic relationship where both species benefit |
| commensalism | a symbiotic relationship where one species benefits and the other is unaffected |
| parasitism | a symbiotic relationship where one species benefits and the other is harmed |
| predation | when one species (predator) kills and eats the other (prey) |
| competition | when two individuals compete for the same resource |
| intraspecies competition | when two individuals of the same species compete for the same resource (such as living space or mate) |
| interspecies competition | when two individuals of different species compete for the same resource (such as living space, food or water) |
| evolution | the change in the inheritable characteristics of a species over many generations |
| natural selection | the mechanism of evolution where individuals better adapted to their environment survive and pass on traits to offspring |
| artificial selection | the mechanism of evolution where humans intentionally choose organisms with desirable traits to reproduce |
| invasive species | a species introduced to a new ecosystem where it is able to aggressively reproduce; its population is insufficiently controlled by native members of the ecosystem |
| native species | a species that naturally occurs in a given ecosystem; it is part of the food web and its population is controlled by other members of the ecosystem |
| biodiversity | the number of different kinds of organisms in a given area |
| keystone species | species that has an unusually large impact on its ecosystem |
