| A | B |
|---|
| Ecosystem | living and nonliving things in the same environment |
| Population | a group of organisms, all the same species |
| Immigration | to enter a population, not by birth |
| Water cycle | the movement of water through the biosphere |
| Carbon cycle | the mvement of carbon through the biosphere, mainly through respiration and photosynthesis |
| Nitrogen cycle | the movement of nitrogen through the biosphere with the help of bacteria fixing the nitorgen |
| Abiotic Factor | a nonliving part of an ecosystem |
| Biotic Factor | a living part of an ecosystem |
| Decomposers | a group of organisms that put the nutrients of dead organisms back into the biosphere |
| Producers | a group of organisms, also called autotrophs, that make their own food, usually through photosynthesis |
| Food web | a diagram showing the feeding relationships and energy flow in an ecosystem |
| Energy pyramid | a diagram showing the energy levels in an ecosystem |
| Biodiversity | the variety of life in an area |
| Habitats | the area where an organism lives |
