1. Cycles of Nature

2. Water Cycle: Review: As we have already learned, water is constantly being cycled and recycled in an ecosystem

3. Nitrogen Cycle: Animals and plants need nitrogen to make protein for growth and development. We rely on nitrogen- fixing bacteria in the soil to change nitrogen into a form plants can use. Animals get nitrogen from eating plants or from eating animals that eat plants.

4. Nitrogen Cycle

5. Oxygen Cycle: Plants release oxygen during photosynthesis, animals release carbon dioxide during respiration. Animals need oxygen for respiration, plants need carbon dioxide for photosynthesis.

6. Oxygen Cycle

7. Carbon Cycle: Plants need carbon dioxide for photosynthesis. Animals release carbon dioxide during respiration into the atmosphere. When plants and animals die, they release carbon dioxide into the soil. Carbon fuels such as coal and oil form over millions of years from the carbon dioxide in the soil. When these fuels are burned they release carbon dioxide into the atmosphere.

8. Carbon Cycle

9. Cycle of Energy: Starts with photosynthesis Formula for photosynthesis: carbon dioxide + water + sunlight = sugar + oxygen

10. Photosynthesis: This process is the single most important energy transformation on earth – changing light energy to chemical energy Producers use photosynthesis to get their energy, which is then passed on from one organism to another in a food chain/web.