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Chapter 5How Ecosystems Work
Lake Victoria   Freshwater lake in Africa   Formerly home to ≈ 400 species of cichlids   1960: Nile perch    introduced...
What Is Ecology?   Literally study of one’s “house”   Interactions   Two components      Biotic      Abiotic   Broad...
Ecological Organization   Organism   Population   Community   Ecosystem   Landscape   Biosphere
Goals Of Ecologists   Understand how ecosystems function   Make connections: landscape ecology     Connections among ec...
Energy   Capacity or ability to do work   Flows through ecosystems   Why do organisms need energy?   Different kinds  ...
First Law of Thermodynamics Energy cannot be  created or  destroyed Energy can be  changed from one  form to another
Second Law of       Thermodynamics When energy is changed from one form  to another, some is degraded into heat Heat is ...
Ecosystem Composition   Producers   Consumers   Decomposers
Producers   Make their own food   Photosynthesis   Examples?        Lii        L           gh            gh            ...
Consumers   Feed on other things   Herbivores   Carnivores   Omnivores   Detrivores
Decomposers   Break down dead organisms and waste    products   Examples?
Energy Flow   Energy passes from one organism to the    next   Trophic level: each step in this flow of    energy   Foo...
Food Chain
FoodWeb
Biogeochemical Cycles   Matter cycles through ecosystems   Five cycles     Carbon     Hydrologic (water)     Nitrogen...
Carbon Cycle   Essential component for life   Gas (CO2) in atmosphere   Several forms in ocean   Can take a long time—...
Carbon Cycle
Hydrologic CycleOcean   Atmosphere   Land   Ocean
Nitrogen Cycle    Proteins, DNA    Atmosphere is 78% N2     Five steps       Nitrogen fixation       Nitrification   ...
Nitrogen Fixation   Specialized bacteria   Split atmospheric nitrogen and combine it    with hydrogen
Nitrogen Cycle
Sulfur Cycle   Underground sedimentary rocks and    minerals   Erosion releases compounds to ocean   Volcanoes   Essen...
Sulfur Cycle
Phosphorus Cycle   No atmospheric component   Phosphates used in DNA and ATP    (chemical energy)   Phosphates move thr...
Phosphorus Cycle
Ecological Niche   Everything about an organism     Adaptations     Use of resources     Lifestyle     Habitat
Ecological Niche   Two species cannot occupy the same    niche: why?   Resource partitioning     Reduces niche overlap ...
Resource Partitioning At Work!
Species Interactions   No species lives in complete isolation   Symbiosis      Intimate relationship between members   ...
Mutualism   Both species benefit
Commensalism   One species benefits, other not affected
Parasitism   Parasite benefits, host is “harmed”   Ectoparasites & endoparasites
Species Interactions   Predation: consumption of one species by    another   Coevolution: “arms race”
Avoiding Predators   Mechanical defenses   Social groups   Camouflage   Protective chemicals
Species Interactions   Competition: two or more organisms    attempting to use the same resource   Intraspecific vs. int...
Keystone Species   Crucial to maintenance of an ecosystem   Loss affects many other    species   Examples?   This idea...
Case Study:        Global Climate Change Atmospheric CO2 increased dramatically.  Why? 10 warmest years have occurred si...
Case Study:          Global Climate Change   Kyoto Protocol – International climate change conference    – Kyoto, Japan 1...
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How ecosystems work.

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  1. 1. Chapter 5How Ecosystems Work
  2. 2. Lake Victoria Freshwater lake in Africa Formerly home to ≈ 400 species of cichlids 1960: Nile perch introduced 1990: water hyacinth invaded Today, ecological imbalance; why?
  3. 3. What Is Ecology? Literally study of one’s “house” Interactions Two components  Biotic  Abiotic Broadest biological field of study
  4. 4. Ecological Organization Organism Population Community Ecosystem Landscape Biosphere
  5. 5. Goals Of Ecologists Understand how ecosystems function Make connections: landscape ecology  Connections among ecosystems  Great blue heron
  6. 6. Energy Capacity or ability to do work Flows through ecosystems Why do organisms need energy? Different kinds Potential energy Kinetic energy
  7. 7. First Law of Thermodynamics Energy cannot be created or destroyed Energy can be changed from one form to another
  8. 8. Second Law of Thermodynamics When energy is changed from one form to another, some is degraded into heat Heat is a less usable form of energy Increases entropy in the universe
  9. 9. Ecosystem Composition Producers Consumers Decomposers
  10. 10. Producers Make their own food Photosynthesis Examples? Lii L gh gh tt e enne errg gyy 6CO2 + 6H2O + ------> C6H12O6 + 6O2
  11. 11. Consumers Feed on other things Herbivores Carnivores Omnivores Detrivores
  12. 12. Decomposers Break down dead organisms and waste products Examples?
  13. 13. Energy Flow Energy passes from one organism to the next Trophic level: each step in this flow of energy Food chain: straight path Food web  Interconnected food chains  More realistic than food chain; why?
  14. 14. Food Chain
  15. 15. FoodWeb
  16. 16. Biogeochemical Cycles Matter cycles through ecosystems Five cycles  Carbon  Hydrologic (water)  Nitrogen  Sulfur  Phosphorus
  17. 17. Carbon Cycle Essential component for life Gas (CO2) in atmosphere Several forms in ocean Can take a long time—think fossil fuels Photosynthesis Cellular respirationCO2 Sugar CO2
  18. 18. Carbon Cycle
  19. 19. Hydrologic CycleOcean Atmosphere Land Ocean
  20. 20. Nitrogen Cycle Proteins, DNA Atmosphere is 78% N2 Five steps  Nitrogen fixation  Nitrification  Assimilation  Ammonification  Denitrification
  21. 21. Nitrogen Fixation Specialized bacteria Split atmospheric nitrogen and combine it with hydrogen
  22. 22. Nitrogen Cycle
  23. 23. Sulfur Cycle Underground sedimentary rocks and minerals Erosion releases compounds to ocean Volcanoes Essential component of proteins
  24. 24. Sulfur Cycle
  25. 25. Phosphorus Cycle No atmospheric component Phosphates used in DNA and ATP (chemical energy) Phosphates move through the food chainLand Organism Organism Land
  26. 26. Phosphorus Cycle
  27. 27. Ecological Niche Everything about an organism  Adaptations  Use of resources  Lifestyle  Habitat
  28. 28. Ecological Niche Two species cannot occupy the same niche: why? Resource partitioning  Reduces niche overlap  Reduces competition
  29. 29. Resource Partitioning At Work!
  30. 30. Species Interactions No species lives in complete isolation Symbiosis  Intimate relationship between members of at least 2 species  Mutualism, commensalism, parasitism  Result of coevolution Other interactions  Predation, competition
  31. 31. Mutualism Both species benefit
  32. 32. Commensalism One species benefits, other not affected
  33. 33. Parasitism Parasite benefits, host is “harmed” Ectoparasites & endoparasites
  34. 34. Species Interactions Predation: consumption of one species by another Coevolution: “arms race”
  35. 35. Avoiding Predators Mechanical defenses Social groups Camouflage Protective chemicals
  36. 36. Species Interactions Competition: two or more organisms attempting to use the same resource Intraspecific vs. interspecific
  37. 37. Keystone Species Crucial to maintenance of an ecosystem Loss affects many other species Examples? This idea is being challenged; why?
  38. 38. Case Study: Global Climate Change Atmospheric CO2 increased dramatically. Why? 10 warmest years have occurred since 1990  2005 warmest  1998 second warmest  2002 third warmest Earth’s temperatures may rise 1.8o – 4.0o C (3.2o – 7.2o F) by end of 21st century What could occur?
  39. 39. Case Study: Global Climate Change Kyoto Protocol – International climate change conference – Kyoto, Japan 1997  Highly developed countries to cut CO2 emissions ~ 5.2% by 2012 US Department of Energy  Automotive vehicles designed for better gas mileage  High efficiency wind turbines
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