Chapter 4 Vocabulary

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Across
  1. 4. process by which bacteria convert nitrates into nitrogen gas
  2. 5. An organism that makes its own food
  3. 8. process of converting nitrogen gas into nitrogen compounds that plants can absorb and use
  4. 11. A community of organisms where there are several interrelated food chains
  5. 13. Microscopic, free-floating, autotrophic organisms that function as producers in aquatic ecosystems
  6. 16. organism that obtains energy from the foods it consumes; also called a consumer
  7. 17. An organism that obtains energy by feeding on other organisms
Down
  1. 1. total amount of living tissue within a given trophic level
  2. 2. diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web
  3. 3. A series of steps in which organisms transfer energy by eating and being eaten
  4. 6. Each step in a food chain or food web
  5. 7. single essential nutrient that limits productivity in an ecosystem
  6. 9. chemical substance that an organism needs to sustain life
  7. 10. Plants use the sun's energy to convert water and carbon dioxide into sugars
  8. 12. process in which elements, chemical compounds, and other forms of matter are passed from one part of the biosphere to another
  9. 14. Dead organic matter
  10. 15. producer first producer of energy-rich compounds that are later used by other organisms
  11. 17. process in which chemical energy is used to produce carbohydrates