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Lecture #2 Outline

Lecture #2 Outline. Energy Flow in Biology Limits and Efficiency Trophic Pyramids . Energy and Matter in Nature Energy Flow: Open System Matter Flows: Recycling. Laws of Thermodynamics 1st Law: Energy Cannot be Made or Destroyed

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Lecture #2 Outline

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  1. Lecture #2 Outline Energy Flow in Biology Limits and Efficiency Trophic Pyramids

  2. Energy and Matter in Nature Energy Flow: Open System Matter Flows: Recycling

  3. Laws of Thermodynamics 1st Law: Energy Cannot be Made or Destroyed 2nd Law: Energy Conversions are Never Perfectly Efficient

  4. Secondary Production Energy Utilization Only a fraction of total energy available actually goes into net production (growth and reproduction)

  5. Efficiency Within Trophic Level Production Efficiency percentage of assimilation energy going to net production (biomass)

  6. Efficiency Within Trophic Level Production Efficiency percentage of assimilation energy going to net production (biomass)

  7. Production Efficiency two basic patterns Birds and Mammals (endotherms) 1% - 3% Insects (ectotherms) 10% - 41%

  8. Efficiency Between Trophic Levels Trophic Level Assimilation Efficiency (Lindeman’s Efficiency)

  9. Between Trophic Level Efficiency Terrestrial systems: approximately 10% Aquatic and Marine systems: 15% - 20%

  10. Birds and mammals have much lower production efficiency than do all other organisms. The energy that endotherms do not put into production goes to: Infrared radiation Urinary wastes Fecal wastes Hair and fur

  11. Trophic Relation Efficiency Graphical Form: Trophic Pyramids Numbers (#/unit area) Biomass (biomass/unit area) Standing Crop energy (kcal/unit area) Energy Flow Rate (kcal/unit area/yr)

  12. 1ha = 10,000m2 or 100m x 100m 0.1 ha = 1000m2 or 100m x 10m

  13. Food chains and trophic pyramids are generally short because: Nutrient limitations Temperature limitations Predators eat too much Energy limitations

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