| A | B |
|---|
| autotrophs | produce own food from sunlight or chemicals |
| producers | make their own food |
| chemosynthesis | use chemical energy to produce carbohydrates |
| heterotrophs | rely on other organisms for food source |
| consumers | heterotrophs are also called |
| food chain | series of steps where organisms transfer energy by eating and being eaten |
| food web | links all the food chains in an ecosystem together |
| trophic level | each step in a food chain or food web |
| ecological pyramid | shows the amount of energy at each trophic level |
| biomass | amount of living tissue in a trophic level |
| evaporation | water changes from liquid to gas |
| transpiration | water enters the atmosphere by evaporating from the leaves of plants |
| nutrients | chemical substances that nutrients need to sustain life |
| nitrogen fixation | process by which bacteria converts nitrogen gas into ammonia |
| denitrification | bacteria converts nitrates into nitrogen gaw that gets released into atmosphere |
| biotic factors | biological influences on an organism |
| abiotic factors | nonliving factors that shape ecosystems |
| resource | any necessity of life |
| ecological succession | predictable changes that occurs in a community over time |
| primary succession | on land, where no soil exists |
| pioneer species | first species to populate an area |
| secondary succession | after a disturbance, ecosystem is returned to original condition |
