Across
- 2. natural strips of land that allow the migration of organisms from one wilderness area to another.
- 3. nonnative species in an area; may take over niches of native species in an area and eventually replace them.
- 4. species that have rapidly decreasing numbers of individuals.
- 5. variety of life in an area; usually measured as the number of species that live in an area.
- 6. when members of a species are held by people in zoos or other conservation facilities.
- 8. programs that release organisms into an area where their species once lived in hopes of reestablishing naturally reproducing populations.
- 9. rain, snow, sleet, or fog with a pH below 7; causes the deterioration of forests, lakes, statues, and buildings.
- 10. field of biology that studies methods and implements plans to protect biodiversity.
- 12. a species in which the number of individuals falls so low that extinction is possible
- 13. philosophy that promotes letting people use resources in wilderness areas in ways that will not damage the ecosystem.
- 14. layer of the atmosphere that helps to protect living organisms on Earth's surface from damaging doses of ultraviolet radiation from the sun.
Down
- 1. when the last members of a species die.
- 2. damage to a habitat by air, water, and land pollution.
- 7. separation of wilderness areas from each other; may cause problems for organisms that need large areas for food or mating.
- 11. different environmental conditions that occur along the boundaries of an ecosystem.