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Activity #3 What’s your trophic level and ecological efficiency?

Activity #3 What’s your trophic level and ecological efficiency?. Use the tables handout from class to collect your dietary data and make calculations. List food items eaten during breakfast, lunch and dinner on a typical day. 

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Activity #3 What’s your trophic level and ecological efficiency?

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  1. Activity #3What’s your trophic level and ecological efficiency? Use the tables handout from class to collect your dietary data and make calculations. List food items eaten during breakfast, lunch and dinner on a typical day.  In the next column, list the source feeding category for each food item. Next, record the relative serving size or portion of each item.  Give a "1" for small, "2" for medium and reserve "3" for the largest portions.  Last record the predominant trophic level of each food item. Sum all the values for portion sizes; this will be used in the calculation table. Follow the steps given in the calculation table to derive your trophic level. Use your trophic level value to calculate your ecological efficiency.

  2. Data Collection Table

  3. Calculation Table for Your Trophic Level Step A: Add all portion values for each diet trophic level separately. The total of these three values should equal the sum of all portion values that you calculated above. Step B: Divide the sum of all portions for each diet TL by the total of all portions to yield the fraction of your diet coming from each trophic level (B = A ÷ total portions). Step C: Multiply the fraction by the diet trophic level value to yield the weighted contribution from each diet trophic level (C = diet TL * B). Step D: Sum the weighted diet trophic level contributions (i.e. sum all three values under “C”). Step E: Add one to the value in “D” to get your trophic level (E = D +1).

  4. My EE = 2.95%

  5. Some herbivores are more efficient than others. 6 % 33% 16 %

  6. Thought Questions: • How would eating more primary producers change your trophic level and ecologically efficiency? • If you ate more fish (secondary consumers), how would these values change? • Primary production represents an energy resource you consume via your diet, either directly like a herbivore or indirectly as a carnivore.  Fossil fuel combustion and nuclear power also represent energy resources used by man. How would total energy use differ for a vegetarian eating exotic vegetables versus someone who's diet is restricted to local harvests ("bioregional" diet)? • How would total energy use differ for someone who's diet is restricted to processed foods and prepackaged cooking kits versus the individual that eats the same diet, but makes their meals from scratch? • What do you imagine would be the most energy efficient diet? • How far are you from that ecologically high efficiency diet and what do you see as the cost and benefits to your normal diet?

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