Vocabulary

4. a mixture of small autotrophic algae in the oceans
6. the nutrient that limits growth of producers
8. the steps in a food chain that represent the amount of energy available to that step
11. a collection of overlapping food chains of an ecosystem
12. the process of using sunlight to create food
14. the process of using chemical energy to create food
16. a collection of all the living tissue in a trophic level or ecosystem
17. the process of converting nitrogen compounds into nitrogen gas

1. all life on Earth and the parts of Earth where life exists
2. substances organisms need to sustain life
3. organisms that consume other organisms for food
5. organisms that create their own food
7. the process of converting nitrogen gas into nitrogen compounds
9. a mixture of small heterotrophic organisms in the oceans
10. nonliving parts of an ecosystem
13. a series of steps in which organisms transfer energy by eating or being eaten
15. living parts of an ecosystem