| A | B |
|---|
| producer | an organism that can make its own food |
| consumer | an organism that obtains energy by feeding on other organisms |
| herbivores | consumers that eat only plants |
| carnivores | consumers that eat only animals |
| omnivores | consumers that eat both plants and animals |
| scavenger | a carnivore that feeds on the bodies of dead organisms |
| decomposers | break down wastes and dead organisms and return the raw materials to the ecosystem |
| food chain | a series of events in which one organism eats another and obtains energy |
| food web | consists of many overlapping food chains in an ecosystem |
| energy pyramid | a diagram that shows the amount of energy that moves from one feeding level to another in a food web |
| water cycle | the continuous process by which water moves from the Earth's surface to the atmosphere and back |
| evaporation | the process by which molecules of liquid water absorb energy and change to a gas |
| condensation | the process by which a gas changes into a liquid |
| precipitation | rain, snow, sleet, or hail that falls back to the Earth |
| nitrogen fixation | the process of changing free nitrogen into a usable form |
