Ecosystem Ecology

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  1. Ecosystem
    interactions of all organisms plus abiotic factors at a given time and place
  2. What are Trophic Levels?
    Feeding niches
  3. Different Trophic Levels
    • autotrophs
    • heterotrophs
  4. Autotrophs
    • "self-feeding"
    • photosynthetic - light energy
    • E.g. plants, algae, blue-green algae
    • chemosynthetic - inorganic chemical energy
    • E.g. certain bacteria
  5. Heterotrophs
    • "other feeding"
    • outside source of organic substances (food)
  6. Energy Flow
    • Movement of Energy
    • Non-cyclic
    • All incoming energy radiated back to outer space
    • Level to level in food chains
  7. Food Chain
    • Series of trophic levels
    • Account of who eats who
  8. Food Chain Levels
    • Primary Producers - Autotrophs
    • Consumers - Heterotrophs
    • Decomposers
  9. Primary Producers (Food Chain)
    • fix light energy into chemical energy (organics)
    • algae, plants, photo- and chemosynthetic bacteria
    • entry point of energy into ecosystem
  10. Consumers (Food Chain)
    • herbivores - eat plants (eat primary producers)
    • carnivores - eat animals (eat consumers)
    • omnivores - eat both plants and animals
  11. Decomposers (food chain)
    • fungi, bacteria, and some animals (e.g. vulture)
    • feed on wastes and dead organisms
  12. Food Web
    Interconnected Food Chains
  13. What percentage is energy used in each trophic level?
    • 70% respiration
    • 20% deaths and waste material
    • 10% growth
  14. What is the 10% rule mean?
    • In energy allocation, 10% of energy is available in the next trophic level
    • 90% energy unavailable to the next level
  15. Energy Pyramid
    • Bar graph
    • Energy at each trophic Level
    • Reflects 10% rule
  16. Should cattle be a food source? (both arguments)
    • Yes: Cattle fed on grass convert food unavailable to humans (grass to available food), and meat contains complete protein while grains do not
    • No: Meat is energetically expensive due to 10% rule; grain that could feed ten humans will, if fed to a cow, feed only one human
  17. Nutrient Cycling
    • Use of materials by organisms
    • Cyclical: reuse of nutrients by organisms
    • Decay of dead organisms and wastes releases nutrients back into the environment for use by other organisms
  18. Types of Nutrient Cycles
    • Local Cycles
    • Global Cycles
  19. Local Cycles
    • No mechanism for Long distance transfer
    • E.g. phosphorus cycle
  20. Global Cycles
    • Long Distance transfer
    • Biosphere
    • E.g. Carbon Cycle
  21. Reservoir
    Available to the organisms
  22. Source
    Not available to organisms
  23. Role of Decomposers in Nutrient Cycle
    • Decay releases nutrients from wastes and dead organisms into the environment for reuse
    • Major difference between energy flow and nutrient cycling
  24. Other Types of Nutrient Cycles
    • Gaseous - reservoir is atmosphere
    • Geological - reservoir is soil
    • Combined - reservoirs in atmosphere and soil
  25. As substances move up food chain, substances are
    • absorbed by organisms
    • do not break down
    • not excreted (stored in fatty tissues)
Card Set:
Ecosystem Ecology
2014-10-18 21:23:19
BIO 181 Exam II
W00t, energy flow and all that funky junk
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