Biology test

3. material made up of decaying bits of plant and animal material
4. a series of steps in an ecosystem in which organisms transfer energy by eating and being eaten
8. single essential nutrient that limits productivity in an ecosystem
9. process of converting nitrogen gas into nitrogen compounds that plants can absorb and use
10. organism that obtains food by consuming other living things; also called a consumer
12. process in which chemical energy is used to produce carbohydrates
15. network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem
17. 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

1. organism that relies on other organisms for its energy and food supply; also called a heterotroph
2. Process in which element, chemical compounds, and other forms of matter are passed off from one organism to another and from one part of the biosphere to another.
3. process by which bacteria convert nitrates into nitrogen gas
5. photosynthetic algae found near the surface of the ocean
6. first poriducer of the energy-rich compounds that are later used by other organisms.
7. organism that is able to capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer
11. total amount of living tissue within a given trophic level
13. each step in a food chain or food web
14. illustration of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web
16. chemical substance that an organism needs to sustain life