KEY CONCEPT Matter cycles in and out of an ecosystem.

1. KEY CONCEPT Matter cycles in and out of an ecosystem.

2. precipitation condensation transpiration evaporation surface runoff lake water storage in ocean groundwater seepage Water cycles through the environment. • The hydrologic, or water, cycle is the circular pathway of water on Earth. • Organisms all have bodies made mostly of water.

3. Elements essential for life also cycle through ecosystems. • A biogeochemical cycle is the movement of a particular chemical through the biological and geological parts of an ecosystem. • The main processes involved in the oxygen cycle are photosynthesis and respiration.

4. oxygen photosynthesis respiration carbon dioxide • Oxygen cycles indirectly through an ecosystem by the cycling of other nutrients.

5. carbon dioxide in air respiration combustion photosynthesis respiration photosynthesis decomposition of organisms carbon dioxide dissolved in water fossil fuels • The carbon cycle moves carbon from the atmosphere, through the food web, and returns to the atmosphere. • Carbon is emitted by the burning of fossil fuels. • Some carbon is stored for long periods of time in areas called carbon sinks. • Carbon is the building block of life.

6. nitrogen in atmosphere animals plant nitrates nitrogen-fixing bacteria in roots decomposers nitrifying bacteria ammonification nitrites nitrogen-fixing bacteria in soil ammonium nitrifying bacteria denitrifying bacteria • Some bacteria convert gaseous nitrogen into ammonia through a process called nitrogen fixation. • Some nitrogen-fixing bacteria live innodules on theroots of plants;others livefreely inthe soil. • The nitrogen cycle mostly takes place underground.

7. nitrogen in atmosphere animals plant nitrates nitrogen-fixing bacteria in roots decomposers nitrifying bacteria ammonification nitrites nitrogen-fixing bacteria in soil ammonium nitrifying bacteria denitrifying bacteria • Nitrifying bacteria change the ammonium into nitrate. • Nitrogen moves through the foodweb and returnsto the soil duringdecomposition. • Ammonia released into the soil is transformed into ammonium.

8. rain geologic uplifting weathering of phosphate from rocks runoff plants animals phosphate in soil phosphate in solution leaching sedimentation forms new rocks decomposers • Phosphate is released by the weathering of rocks. • Phosphorus moves through the food web and returns to the soil duringdecomposition. • The phosphorus cycle takes place at and below ground level. • Phosphorus leaches into groundwater from the soil and is locked in sediments. • Both mining and agriculture add phosphorus into the environment.

9. The water cycle, in which water moves from the atmosphere, to the surface, below ground and back is called • Biogeochemical cycle • Oxygen cycle • Hydrologic cycle • Nitrogen cycle

10. Which two biogeochemical cycles depend directly on photosynthesis? • Hydrologic cycle and oxygen cycle • Carbon cycle and phosphorous cycle • Nitrogen cycle and phosphorous cycle • Oxygen cycle and carbon cycle

11. Fossil fuels are part of which of the following cycles? • Oxygen • Carbon • Nitrogen • Phosphorous

12. What happens during the process of nitrogen fixation? • Bacteria changes ammonium into nitrate • Bacteria grows on nodules on plant roots • Bacteria absorb ammonia and excrete ammonium • Bacteria convert gaseous nitrogen into ammonia

13. Where does most of the phosphorous cycle take place? • In the atmosphere • At and below ground level • On fungi near plant roots • Close to rocky terrain