2. Nature’s Cycles The Earth’s Natural Recycling Process

3. Nutrient Cycles Outline I. Water Cycle 1. evaporation 2. transpiration 3. precipitation II.Carbon 1. Plants 2. Animals III. Nitrogen 1. Air 2. Nitrogen-fixing bacteria

4.  Matter cycles from the environment to organisms then back to the environment.  ENERGY DOES NOT CYCLE!!!

5. WATER CYCLE  2 ways water enters the atmosphere: –Evaporation: water moves into the atmosphere as it changes from liquid to gas –Transpiration: evaporation of water from the leaves of plant through open stomata

6. Water Cycle  Clouds form as vapors cool and condense  Condensation – water changing from a gas to a liquid (e.g. clouds, water on a window)  Precipitation – water returning to earth in the form of rain, snow, sleet, hail.  Precipitation can return to oceans through runoff or groundwater

8. Glaciers

11. The Carbon Cycle

12. Carbon Cycle  The original atmosphere was 95% carbon dioxide but now less than 1%  Carbon entered the ecosystem as plants removed carbon dioxide from air during photosynthesis  Consumers eat plants (and therefore carbon) and release it back into the atmosphere in the form of carbon dioxide during respiration

13. The Carbon Cycle: The Circle of Life  Dirt becomes corn, which is eaten by cows.  The cows are then eaten by humans.  The humans are eaten by worms, which decompose what they eat.  The decomposed nutrients (i.e. carbon) return to the soil.  The cycle then repeats.

14.  Organisms: composed mainly of carbon  Ocean: carbon dioxide dissolves easily in water  Rocks: bodies of dead organisms that didn’t decompose; carbon dioxide released into the air when we burn fossil fuels So where is the rest?

15. Oil in Alaska

16. The Nitrogen Cycle  Why is nitrogen important? –All organisms need nitrogen to make proteins (amino acids)!  Air is 78% nitrogen (N 2 )!, However, there is a shortage!  If 78% of the atmosphere is nitrogen, why is there a shortage? –Plants can’t use nitrogen gas in that form

17. How do we solve the nitrogen shortage problem?  Bacteria to the rescue! Bacteria can use it!  Nitrogen fixing Bacteria: live on the roots of plants and “fix” nitrogen by turning it into a usable form (e.g. ammonia, nitrite, nitrate).  Example: Legumes (peanuts, beans, clover)

18. Nitrogen Cycle  Animals get nitrogen from eating plants  When animals die, decomposers break them down and release nitrogen gas back into the atmosphere and return some to the soil so plants can reuse it.  However, when there isn’t enough nitrogen available, fertilizer is necessary!!

19. The Nitrogen Cycle Animals eat plants and each other 1 2 4 5 Decomposers break down plants and animals 3

20. THE END!!!

21. Answer this question in your notes…  Explain why almost all biologists believe in re-incarnation from a scientific perspective.  Answer: Because matter is not created or destroyed – it is all recycled!