| A | B |
|---|
| natural resource | anything in the environment that is used by people |
| renewable resource | a natural resource that is either always available or naturally replaced in a relatively short time |
| nonrenewable resource | a natural resource that is not replaced in a useful time frame |
| pollution | the contamination of earth's land, water, or air |
| environmental science | the study of natural processes in the environment and how humans can affect them |
| clear-cutting | the process of cutting down all the trees in an area |
| selective cutting | cutting down only some trees in a forest and leaving a mix of tree sizes and species behind |
| sustainable yield | an amount of a renewable resource such as trees that can be harvested regularly without reducing future supply |
| fishery | an area with a large population of ocean organisms |
| aquaculture | the practice of raising fish and other water-dwelling organisms for food |
| biodiversity | the number of different species in an area |
| keystone species | a species that influences the survival of many other species in an ecosystem |
| extinction | the disappearance of all members of a species from earth |
| endangered species | a species in danger of becoming extinct in the near future |
| threatened species | species that could become endangered in the near future |
| habitat destruction | a loss of natural habitat |
| habitat fragmentation | the breaking of larger habitats into smaller, isolated pieces or fragments |
| poaching | the illegal killing or removal of wildlife from their habitats |
| captive breeding | the mating of animals in zoos or wildlife preserves |
