Bio Ch. 4

2. chemical energy is used to produce carbohydrates and sulfur compounds
4. organisms that rely on other organisms for energy and nutrients
7. a series of organisms in which energy is transferred from one organism to another
8. each step in the food chain or web (each part of the pyramid)
12. can capture energy from nonliving sources and convert it into forms living cells can use
14. only certain types of bacteria can convert nitrogen gas into ammonia
15. elements that an organism needs to sustain life
16. must acquire energy from other organisms, usually by eating them
18. models that show the relative amount of energy or matter in each trophic level

1. a nutrient whose supply limits productivity
3. first producers of energy-rich compounds that can be used later by other organisms
5. when matter flows from one trophic level to another and elements are recycled within and among ecosystems
6. network of feeding interactions through which both energy and matter move
9. converting nitrates into nitrogen gas
10. tiny floating algea
11. small pieces of dead and decaying plant and animal remains
13. uses energy to convert carbon dioxide and water into oxygen and carbohydrates
17. the total amount of living tissue within a given trophic level