1. Ecosystems and Livig Organisms Chapter 4

2. The Gaia Theory Dynamic Equilibrium Negative Feedback Positive Feedback The Gaia Theory: The organic and inorganic components of Planet Earth have evolved together as a single living, self-regulating system. In a phrase, “life maintains conditions suitable for its own survival.”

3. Biogeochemical Cycle The complete path a chemical takes through the three primary reservoirs or “sinks” of Earth’s systems: 1.Atmosphere 2.Hydrosphere 3.Lithosphere

4. Cycles Carbon 1.Lipids 2.Nucleic Acids 3.Carbohydrates 4.Amino Acids Nitrogen 1.Amino Acids Phosphorus 1.ATP 2.DNA 3. Cell Membranes Sulfur 1.Amino Acids 2.Keratin Fixed amounts of all elements on earth * Oxidation describes the loss of electrons by a molecule, atom or ion * Reduction describes the gain of electrons by a molecule, atom or ion

5. Carbon Cycle Billions of Tons http://www.youtube.com/watch?v= 0Vwa6qtEih8&feature=related

6. Carbon Silicate A weathering Cycle: 1.Atmospheric CO 2 forms H 2 CO 3 (Carbonic Acid) precipitation which moves through soil 2.H 2 CO 3 dissociates & forms H + & HCO - 3 (bicarbonate) 3.Silicate rich minerals interact with the free H + to release Ca 2+ 4.Shellfish 5.Subduction – silicate formation at temperatures above 300 °C

7. Carbon Silicate Believed to provide important negative feedback mechanisms that control the temperature of the atmosphere.

8. Nitrogen cycle Nitrogen cycle: Atmospheric nitrogen (N 2 ) Nitrogen fixation by humans Biological nitrogen 1. fixation 2. Nitrification NH 3 & NH 4 - NO 3 - 3. Assimilation 5.Denitrification Plant & animal proteins Decomposition - urea 4. Ammonification Internal cycling (Ammonia) Lightning Volcanoes Bacteria (Nitrates & Nitrites) (Oxidation) NO 3 - → NO 2 - → NO → N 2 O → N 2 gas

9. Nitrogen Cycle & Steps 1.Nitrogen Fixation is the conversion of elemental nitrogen(N 2 ) to organic ammonia(NH 3 ) by bacteria, lightning, industry, volcanoes. 2.Nitrification - conversion of ammonia or ammonium (NH 4 ) into nitrites(NO - 2 ) and then into nitrates (NO - 3 ) by bacteria 3.Assimilation- plants absorb nitrates or ammonia 4.Ammonification - nitrogen is converted into ammonia from animal waste or dead organisms by aerobic bacteria 5.Denitrification - anaerobic bacteria convert nitrates & nitrites to nitrogen gasses off to atmosphere 1.Nitrogen is not a reactive molecule 2.78% atmosphere N 2 & 21% oxygen &.038% CO 2 YouTube: http://www.youtube.com/watch?v=m4YToXw724w&feature=relatedhttp://www.youtube.com/watch?v=m4YToXw724w&feature=related

10. Phosphorus Cycle Does not include the atmosphere YouTube: http://www.youtube.com/watch?v=RKkC2JpjaGc&feature=related http://www.youtube.com/watch?v=RKkC2JpjaGc&feature=related

11. Phosphorus Cycle

12. Phosphorus Brazil

13. Guano

14. Accelerated Eutrophication

15. Cycling of Materials within Ecosystems Sulfur cycle: YouTube: http://www.youtube.co m/watch?v=BzPeA9oQ Nl8 http://www.youtube.co m/watch?v=BzPeA9oQ Nl8

17. Cycling of Materials within Ecosystems Hydrologic cycle: