Ecology

4. any natural resource that can replenish itself naturally over time
6. the specific role of a species within its environment
7. the introduction of harmful substances or products into the environment
10. trees that lose all of their leaves in the fall and regrow them each spring
18. the place where an organism usually lives
20. a relationship where one organism is harmed and the other organism benefits
22. a species at risk of extinction because of human activity, changes in climate, changes in predator-prey ratios, etc
24. living components of the ecosystem
25. a relationship in which both organisms benefit

1. the coniferous evergreen forests of subarctic lands, covering vast areas of northern North America and Eurasia.
2. one of the vast, nearly level, treeless plains of the arctic regions of Europe, Asia, and North America.
3. the process of one community replacing another community that has been partially or completely destroyed
5. the part of earth where life exists; includes all living organisms on earth
8. any natural resource from the Earth that exists in limited supply and cannot be replaced if it is used up
9. a group of organisms that belong to the same species and live in a particular place at the same time
11. the study of the interactions between organisms and other living and nonliving components in their environment
12. the development of a community in an area that has never supported life
13. a relationship where one organism benefits while the other organism is not affected
14. an organism that lives by breaking down organic matter from dead organisms
15. a close, long-term relationship between two organisms
16. an organism that is able to make its own food
17. tropical or temperate grasslands that have scattered deciduous trees and shrubs
19. an organism, usually an animal, that feeds on plants or other animals.
21. a community of organisms and their abiotic environment
23. non-living components of the ecosystem; physical and chemical characteristics of the environment