Across
- 2. Nonnative species in an area
- 4. Variety of life in an area
- 7. When the last members of a species die
- 8. Field of biology that studies methods and implements plans to protect biodiversity
- 11. When members of a species are held by people in zoos or other conservation facilities
- 12. Separation of wilderness areas from each other
- 14. Species that have rapidly decreasing numbers of individuals
- 15. Rain, snow, sleet, or fog with a pH below 7
Down
- 1. Philosophy that promotes letting people use resources in wilderness areas in ways that will not damage the ecosystem
- 3. Different environmental conditions that occur along the boundaries of an ecosystem
- 5. Programs that release organisms into an area where their species once lived in hopes of reestablishing naturally reproducing populations
- 6. Layer of the atmosphere that helps to protect living organisms on earths surface from damaging doses of ultra violent radiation from the sun
- 9. Damage to a habitat by air, water, and land pollution
- 10. A species in which the number of individuals falls so low that extinction is possible
- 13. Natural strips of land that allow the migration of organisms from one wilderness area to another