Key Terms

3. The regions of Earth where living organisms exist
4. The non-living parts of an ecosystem
5. An ecosystem that is land-based
8. An ecosystem that is water-based, either fresh water or salt water
9. An ecosystem that is capable of withstanding pressure and giving support to a variety of organisms
12. A measure of the amount of energy or biomass transferred from one trophic level to the next higher trophic level
13. Atmospheric gases that prevent heat from leaving the atmosphere, thus increasing the temperature of the atmosphere
15. The hard part of Earth's surface
18. All the interacting parts of a biological community and its environment
19. The layer of gases above Earth
20. A chemical that is essential to living things and is cycled through ecosystems
21. A process that releases energy from organic molecules, especially carbohydrates in the absence of oxygen
22. The living parts of an ecosystem

1. The warming of Earth as a result of greenhouse gases which trap some of the energy that would otherwise leave Earth
2. A category of organisms that is defined by how the organisms gain their energy
6. The total mass of living organisms in a defined group or area
7. A process in which nutrient levels in aquatic ecosystems increase, leading to an increase in the populations of primary producers
10. A process that releases energy from organic molecules, especially carbohydrates in the presence of oxygen
11. Rain, snow, or fog that is unnaturally acidic due to gases in the atmosphere that react with water
14. All the water found on Earth, including lakes, oceans, and ground water
16. A process that changes solar energy into chemical energy
17. A process in which materials especially toxins, are ingested by an organism at a rate greater than they are eliminated