Unit 4 Biology Vocab

2. A 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
4. A series of steps in an ecosystem in which organisms transfer energy by eating and being eaten
7. A material made up of decaying bits of plant and animal material
8. An organism that relies on other organisms for its energy and food supply; also called a heterotroph
10. An organism that obtains food by consuming other living things; also called consumers
14. The process in which elements, chemical compounds, and other forms of matter are passed from one part of the biosphere to another
15. An 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
16. The process by which bacteria converts nitrates into nitrogen gas

1. Each step in a food chain or food web
3. A process of converting nitrogen gas into nitrogen compounds that plants can absorb and use
5. A chemical substance that an organism needs to sustain life
6. First producer of energy-rich compounds that are later used by other organisms
9. The total amount of living tissue within a given trophic level
11. A model of the relative amounts of energy or matter contained within each trophic level in a given food chain or food web
12. A network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem
13. A process in which chemical energy is used to produce carbohydrates