Biog 2: Trophic hierarchies 09

  1. Trophic level:
    • the position an organism occupies in a food chain
    • Where we live: trees/plants are the most important
  2. Laws of Thermodynamics:
    • 1. Energy is not created or destroyed in a closed system
    • 2. When energy is transferred or transformed between units in a system, parts of the energy assumes a form that cannot pass any further
  3. Ecological efficiency:
    the rate at which energy or biomass is transferred from one trophic level to the next
  4. Primary producers energy:
    • 5.6% of energy converted to biomass, the rest lost to respiration
    • the further up the chain, the less biomass is available
  5. 10% rule:
    only about 10% of energy from 1 trophic lvl to the next is converted into biomass (90% lost)
  6. Producers and Consumers MN Ex:
    • Primary producers, primary, 2ndary consumers
    • Bur Oak acorns, Muskrat, gold eagle
  7. Biomass pyramid:
    • 10g m2   (2ndary consumers)
    • 100g m2  (primary consumers)
    • 1000g m2  (producers)
  8. Carrying capacity:
    • ('K'): estimates how many individuals of a particular organism can be supported by a specific habitat.
    • (Ex: Producers- many; 2ndary consumers- few)
  9. From one trophic lvl to the next:
    • size and number of individuals often scale by approx. factor of 10
    • Ex: #1000, size 1; #100, size 10, etc)
Card Set
Biog 2: Trophic hierarchies 09