Ecology - Chapter 5 Section 2


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Ecology - Chapter 5 Section 2

  1. 1. Chapter 5, Section 2<br />The Cycling of Materials<br />
  2. 2. The Carbon Cycle<br />
  3. 3. The Carbon Cycle<br />Carbon is an essential component of proteins, fats, and carbohydrates, which make up all organisms.<br />The carbon cycle is a process by which carbon is cycled between the atmosphere, land, water, and organisms.<br />
  4. 4. The Carbon Cycle<br />
  5. 5. The Carbon Cycle: Short-Term<br />Producers convert carbon dioxide in the atmosphere into carbohydrates during photosynthesis.<br />Consumers eat producers and obtain carbon from the carbohydrates.<br />During cellular respiration, some of the carbon is released back into the atmosphere as carbon dioxide.<br />
  6. 6. The Carbon Cycle: Long-Term<br />Carbon can be converted into carbonates.<br />Bones, shells, limestone rock<br />Carbon can be converted into molecules that store energy. <br />Fats and oils<br />This carbon is not released until the organism dies.<br />These dead organisms form coal, oil, and natural gas.<br />
  7. 7. How Humans Affect the Carbon Cycle<br />We alter the carbon cycle by…<br />Clear trees and plants that absorb CO2 through photosynthesis faster than they can grow back<br />Add large amounts of CO2 by burning fossil fuels and wood.<br />Increased concentrations of can enhance the planet’s natural greenhouse effect. <br />Global warming disrupts global food production and wildlife habitats, alter temperature and precipitation patterns, and raise the average sea level in various parts of the world.<br />
  8. 8. High<br />projection<br />Low<br />projection<br />CO2 emissions from fossil fuels<br />(billion metric tons of carbon equivalent)<br />Year<br />
  9. 9. The Nitrogen Cycle<br />
  10. 10. The Nitrogen Cycle<br />All organisms need nitrogen to build proteins which are used to build new cells.<br />Nitrogen makes up 78% of the gases in the atmosphere.<br />Most organisms cannot use atmospheric nitrogen.<br />
  11. 11. The Nitrogen Cycle<br />Nitrogen-fixing bacteria are the only organisms than can convert bacteria into usable chemical compounds.<br />Nitrogen-fixing bacteria live on the roots of legumes.<br />Use sugars to produce nitrogen-containing compounds.<br />Excess nitrogen is released into the soil<br />
  12. 12. The Nitrogen Cycle<br />All other organisms depend on these bacteria to supply the nitrogen they need for survival.<br />Animals get nitrogen from eating plants or other animals that contain usable sources of nitrogen.<br />The nitrogen cycle is a process in which nitrogen is cycled between the atmosphere, bacteria, and other organisms.<br />
  13. 13. The Nitrogen Cycle<br />
  14. 14. Decomposers and the Nitrogen Cycle<br />Decomposers break down wastes and decaying organisms to return nitrogen to the soil.<br />If decomposers did not exist, nitrogen would be stored forever in wastesand corpses.<br />
  15. 15. Effects of Human Activities on the Nitrogen Cycle<br />We add large amounts of nitric oxide (NO) into the atmosphere when N2 and O2 combine as we burn any fuel at high temperatures.<br />This gas can be converted to nitrogen dioxide gas (NO2) and nitric acid (HNO3) which can return to the Earth’s surface as acid rain.<br />We add nitrous oxide (N2O) to the atmosphere through the action of anaerobic bacteria on livestock wastes and commercial inorganic fertilizers applied to soil.<br />This gas can warm the atmosphere and deplete ozone in the stratosphere.<br />
  16. 16. Effects of Human Activities on the Nitrogen Cycle<br />Nitrate ions in inorganic fertilizers can leach through the soil and contaminate groundwater. <br />This is harmful to drink, especially for infants and small children.<br />We release large quantities of nitrogen stored in soils and plants as gaseous compounds into the troposphere through destruction of forests, grasslands, and wetlands.<br />We upset aquatic ecosystems by adding excess nitrates to bodies of water through agricultural runoff and discharges from municipal waste systems.<br />
  17. 17. Effects of Human Activities on the Nitrogen Cycle<br />We remove nitrogen from topsoil when we harvest nitrogen-rich crops, irrigate crops, and burn or clear grasslands and forests before planting crops.<br />Since 1950 human activities have more than doubled the annual release of nitrogen from the terrestrial portion of the earth into the rest of the environment.<br />This is a serious local, regional, and global environmental problem that has attracted little attention when compared to global warming and depletion of the ozone layer.<br />
  18. 18. The Phosphorus Cycle<br />
  19. 19. The Phosphorus Cycle<br />Phosphorus is needed to form bones and teeth.<br />Plants get phosphorus from soil and water.<br />Animals get phosphorus from eating plants or other animals who have eaten plants.<br />The phosphorus cycle is the movement of phosphorus from the environment to organisms and then back to the environment.<br />
  20. 20. The Phosphorus Cycle<br />Phosphorus may enter soil<br />When rocks erode, phosphorus dissolves in soil and water. Plants absorb the phosphates through their roots.<br />Phosphorus is added to soil and water when excess phosphorus is excreted in waste or when organisms die and decompose.<br />Phosphorus washes off the land and ends up in the ocean. These phosphate salts sink to the bottom of the ocean and accumulate as sediment.<br />
  21. 21. The Phosphorus Cycle<br />
  22. 22. Effects of Human Activities on the Phosphorous Cycle<br />We mine large quantities of phosphate rock to make commercial inorganic fertilizers and detergents.<br />We reduce the available phosphate in tropical soils when we cut down areas of tropical forests.<br />We disrupt aquatic systems with phosphates from runoff of animal wastes and fertilizers and discharges from sewage treatment systems.<br />Human activities have increased the natural rate of phosphorous about 3.7 times since 1900.<br />
  23. 23. Summary Questions<br />How can driving a car affect the carbon cycle?<br />Explain how the excessive use of fertilizer affects the nitrogen cycle and the phosphorus cycle.<br />Explain why the phosphorus cycle occurs more slowly than both the carbon cycle and the nitrogen cycle.<br />