| A | B |
|---|
| abiotic factor | nonliving aspect of the environment such as sunlight and soil |
| biomass | total mass of organisms at a trophic level |
| biotic factor | living aspects of the environment, including organisms of the same and different species |
| carnivore | consumer that eats animals |
| chemoautotroph | producer that uses energy from chemical compounds to make food by chemosynthesis |
| competitive exclusive principle | principle of ecology stating that two different species cannot occupy the same niche in the same place for very long |
| decomposer | organism that breaks down the remains of dead organisms and other organic wastes |
| detritivore | decomposer that consumes detritus |
| detritus | substance composed of dead leaves, other plant remains, and animal feces that collects on the soil or at the bottom of a body of water |
| ecology | branch of biology that is the study of how living things interact with each other and with their environment |
| food chain | diagram that represents a single pathway through which energy and matter flow through an ecosystem |
| food web | diagram that represents multiple intersecting pathways through which energy and matter flow through an ecosystem |
| habitat | physical environment in which a species lives and to which it has become adapted |
| herbivore | consumer that eats producers such as plants or algae |
| niche | role of a species in its ecosystem that includes all the ways the species interacts with the biotic and abiotic factors of the ecosystem |
| omnivore | consumer that eats both plants and animals |
| photoautotroph | producer that uses energy from sunlight to make food by photosynthesis |
| saprotroph | decomposer such as a fungus or protozoan that feeds on any remaining organic matter that is left after other decomposers do their work |
| scavenger | decomposer that consumers the soft tissues of dead animals |
| trophic level | feeding position in a food chain or food web, such as producer, primary consumer, or secondary consumer |
| carbon cycle | interconnected pathways through which carbon is recycled through the biotic and abiotic components of the biosphere |
| nitrogen cycle | interconnected pathways through which nitrogen is recycled through the biotic and abiotic components of the biosphere |
| nitrogen fixation | process of changing nitrogen gas to nitrates that is carried out by nitrogen-fixing bacteria in the soil or in the roots of legumes |
| water cycle | interconnected pathways through which water is recycled through the biotic and abiotic components of the biosphere |
| aquatic biome | water-based biomes, defined by the availability of sunlight and the concentration of dissolved oxygen and nutrients in the water |
| terrestrial biome | a biome of or pertaining to land, as in terrestrial ecosystem |
| wetland | area that is saturated with water or covered by water for at least one season of the year |
| freshwater biome | aquatic biome such as a pond, lake, stream, or river in which the water contains little or no salt |
| marine biome | aquatic biome in the salt water of the ocean |
| dormancy | state in which a plant slows down cellular activity and may shed its leaves |
| estuary | a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the ocean |
