Biology: Chapter 4 Vocabulary Crossword

2. Network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem
5. Single essential nutrient that limits productivity in an ecosystem
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
8. Total amount of living tissue within a given trophic level
9. Series of steps in an ecosystem in which organisms transfer energy by eating and being eaten
14. Process by which bacteria convert nitrates into nitrogen gas
16. Organism that relies on other organisms for its energy and food supply; also called a heterotroph
17. Chemical substance that an organism needs to sustain life
18. Material made up of decaying bits of plant and animal material

1. Model of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web
3. Process in which chemical energy is used to produce carbohydrates
4. Process of converting nitrogen gas into nitrogen compounds that plants can absorb and use
6. Photosynthetic algae found near the surface of the ocean
10. 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
11. Process in which elements, chemical compounds, and other forms of matter are passed from one part of the biosphere to another
12. First producer of energy-rich compounds that are later used by other organisms
13. Organism that obtains food by consuming other living things; also called consumers
15. Each step in a food chain or food web