| Term | Definition |
|---|---|
| abiotic factor | nonliving thing in an ecosystem |
| atmosphere | layer of gases surrounding Earth |
| biotic factor | living thing in an ecosystem |
| climate | average weather conditions in an area over time |
| ecosystem | living and nonliving things in a given area |
| bacteria | unicellular organisms without a membrane-bound nucleus |
| condensation | process during which water vapor changes into liquid water |
| element | cannot be separated by chemical means |
| evaporation | process during which liquid water changes into water vapor |
| nitrogen fixation | process that changes atmospheric nitrogen into compounds usable by living things |
| precipitation | water that falls from clouds to the Earth's surface |
| release | to set free |
| chemosynthesis | process using chemical energy in matter to make food |
| food chain | model showing how energy flows in an ecosystem |
| food web | model of energy transfer showing how the food chains in a community are interconnected |
| energy pyramid | model showing the amount of energy available in each step of a food chain |
| photosynthesis | series of chemical reactions that convert light energy, water, and carbon dioxide into the food-energy molecule glucose and give off oxygen |
