Biology Ch. 4 Vocab

1. organism that obtains food by consuming other living things
3. in which elements, chemical compounds, and other forms of matter are passed from one part of the biosphere to another
4. process by which bacteria convert nitrates into nitrogen gas
7. chemical substance that an organism needs to sustain life
9. process in which chemical energy is used to produce carbohydrates
11. series of steps in an ecosystem in which organisms transfer energy by eating and being eaten
14. each step in a food chain or food web
17. single essential nutrient that limits productivity in an ecosystem

2. model of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web
5. process used by plants and other autotrophs to capture light energy and use it to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates such as sugars and starches
6. process of converting nitrogen gas into nitrogen compounds that plants can absorb and use
8. total amount of living tissue within a given trophic level
9. organism that relies on other organisms for its energy and food supply
10. organism that is able to capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds
12. material made up of decaying bits of plant and animal material
13. network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem
15. photosynthetic algae found near the surface of the ocean
16. first producer of energy-rich compounds that are later used by other organisms