| A | B |
|---|
| producer | An organism that can make its own food. |
| consumer | An organism that obtains energy by feeding on other organisms. |
| herbivore | Consumer that eats only plants. |
| carnivore | Consumer that eats only animals. |
| omnivore | Consumer that eats both plants and animals. |
| scavenger | A carnivore that feeds on the bodies of dead organisms. |
| decomposer | An organism that breaks down wastes and dead organisms. |
| food chain | A series of events in which one organism eats another. |
| food web | The pattern of 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 a liquid absorb energy and change to the gas state. |
| condensation | The process by which a gas changes to a liquid. |
| precipitation | Rain, snow, sleet, or hail. |
| nitrogen fixation | The process of changing free nitrogen gas into a usable form. |
| nodules | Bumps on the roots of certain plants that house nitrogen-fixing bacteria. |
| biogeography | The study of where organisms live. |
| continental drift | The very slow motion of the continents. |
| dispersal | The movement of organisms from one place to another. |
| native species | Species that have naturally evolved in an area. |
| exotic species | Species that are carried to a new location by people. |
| climate | The typical weather pattern in an area over a long period of time. |
| biome | A group of ecosystems with similar climates and organisms. |
| canopy | A leafy roof formed by tall trees. |
| understory | A layer of shorter plants that grow in the shade of a forest canopy. |
| desert | An area that receives less than 25 cm of precipitation a year. |
| grassland | An area populated by grasses that gets 25 to 75 cm of rain each year. |
| savanna | A grassland close to the equator. |
| deciduous trees | Trees that shed their leaves and grow new ones each year. |
| hibernation | A low-energy state similar to sleep that some mammals enter in the winter. |
| coniferous trees | Trees that produce their seeds in cones and have needle-shaped leaves. |
| tundra | An extremely cold, dry biome. |
| permafrost | Soil that is frozen all year. |
| estuary | A habitat in which the fresh water of a river meets the fresh water of the ocean. |
| intertidal zone | The area between the highest high-tide line and lowest low-tide line. |
| neritic zone | The region of shallow ocean water over the continental shelf. |
| succession | The series of predictable changes that occur in a community over time. |
| primary succession | The changes that occur in an area where no ecosystem had existed. |
| pioneer species | The first species to populate an area. |
| secondary succession | The changes that occur after a disturbance in an ecosystem. |
