1. U4 – How Ecosystems Work The cycling of materials

2. Carbon Cycle Consumers eat producers to get carbs. Consumers/Producers do cellular respiration (break food down), produce CO 2.

3. Long-Term C Cycle Carbonates (bones/shells) – don’t break down easily, build up to make carbon sinks (source) X. Limestone Fossil Fuels – stored carbon left from dead things…makes oil, coal, natural gas….

4. Human Impact Burning Fossil Fuels (fires, cars…)– makes excess CO 2. CO 2 – greenhouse gas (global warming)

6. Nitrogen Cycle N – needed to make proteins. N – 78% of atmosphere. Most organisms can’t use the N in the atmosphere. Nitrogen-fixing bacteria convert N into NH 3 (ammonia) so plants/animals can use it. X. Legumes Decomposers – break down wastes (leaves, dung, dead stuff…) to recycle N.

8. Phosphorus Cycle P – essential bones/teeth. Plants – get P from soil/water. Animals – get P from eating plants. P Cycle doesn’t normally occur in the atmosphere b/c P isn’t usually a gas.

10. Fertilizers Contain N and P (increase plant growth) Enters aquatic ecosystems through runoff (waterways). Excess N and P cause algal bloom. Algae deplete O in ecosystem.

12. Acid Precipitation Nitric Oxide – harmful gas produced by burning coal, wood, and oil. Nitric oxide combines with O 2 and H 2 O vapor in atmosphere to make acid precipitation.