| A | B |
|---|
| abiotic factor | a nonliving part of an organism's habitat |
| adaptation | a behavior or physical characteristic that allows an organism to survive or reproduce in its environment |
| autotroph | an organism that makes its own food |
| biotic factor | a living part of an organism's habitat |
| carnivore | a consumer that eats only animals |
| chlorophyll | a green pigment found in the chloroplasts of plants, algae, and some bacteria |
| chloroplast | a structure in the cells of plants and some other organisms that captures energy from sunlight and uses it to produce food |
| commensalism | a relationship between two species in which one species benefits and the other is neither helped nor harmed |
| community | all the different populations that live together in an area |
| competition | the struggle between organisms to survive as they attempt to use the same limited resource |
| consumer | an organism that obtains energy by feeding on other organisms |
| decomposer | an organism that breaks down chemicals from wastes and dead organisms, and returns important materials to the soil and water |
| ecology | the study of how organisms interact with their environment |
| ecosystem | the community of organisms that live in a particlular area, along with their nonliving surroundings |
| energy pyramid | a diagram that shows the amount of energy that moves from one feeding level to another in a food web |
| food chain | a series of events in which one organism eats another and obtains energy |
| habitat | the specific enviornment that provides things an organism needs to live, grow, and reproduce |
| herbivore | a consumer that eats only plants |
| heterotroph | an organism that cannot make its own food |
| host | the organism that a parasite or virus lives in or on |
| lichen | the combination of a fungus and algae that live together in a mutualistic relationship |
| life science | the study of living things |
| mutualism | a close relationship between organisms of two species in which both organisms benefit |
| natural selection | a process by which individuals that are better adapted to their environment are more likely to survive and reproduce than others of the same species |
| niche | the role of an organism in its habitat or how it makes its living |
| omnivore | a consumer that eats both plants and animals |
| organism | a living thing |
| parasite | the organism that benefits by living on or in a host in a parasitism interaction |
| parasitism | a relationship in which one organism lives on or in a host and harms it |
| photosynthesis | the process in which some organisms use water along with sunlight and carbon dioxide to make their own food |
| population | all the members of one species in a particular area |
| population density | the number of individuals in an area of a specific size |
| precipitation | rain, snow, sleet, or hail |
| predation | an interaction in which one organism kills another for food |
| predator | the organism that does the killing in a predation interaction |
| prey | an organism that is killed and eaten by another organism |
| producer | an organism that can make its own food |
| scavenger | a carnivore that feeds on the bodies of dead organisms |
| species | a group of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce |
| symbiosis | a close relationship between two organisms of different species that benefits at least one of the organisms |
| water cycle | the continuous process by which water moves from Earth's surface to the atmosphere and back |
| nitrogen fixation | the process of changing nitrogen gas into forms that plants can use |
| carbon cycle | the movement of carbon from the nonliving environment into living things and then back into the nonliving environment: producers take in carbon dioxide gas from the air during photosynthesis |
| nitrogen cycle | nitrogen moves from the air to the soil, into living things, and back into the air |
| evaporation | the process by which molecules of a liquid absorb energy and change it to a gas |
