Across
- 2. nonnative species in an area.
- 3. layer of the atmosphere that helps to protect the living organisms on Earth's surface from damaging doses of ultraviolet radiation from the Sun.
- 5. a species that is in danger of becoming extinct.
- 6. damage to a habitat by air, water, and land pollution
- 10. different environmental conditions that occur along the boundaries of an ecosystem.
- 11. when members of a species are held by people in zoos or other conservation facilities.
- 12. when the last members of the species dies.
- 13. separation of wilderness areas from each other.
- 14. philosophy that promotes letting people use resources in the wilderness areas in ways that will not damage the ecosystem.
Down
- 1. species that have rapidly decreasing numbers of individuals.
- 4. programs that help release animals back into their old habitats.
- 6. natural strips of land that allow the migration of organisms from one ecosystem to another.
- 7. variety of life in an area.
- 8. rain, snow, sleet, or fog with a pH below 7.
- 9. field of biology that studies methods and implements plans to protect biodiversity.