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