Assessment Items from the Ecology 1 Small Group

Overall objective: Understand the relationship between energy and matter in ecological systems

Learning Outcome:

Be able to calculate biomass in varying trophic levels given trophic efficiencies and levels of incoming solar radiation

Formative Assessment Question:

Consider the following information: 1,200,000 kC of solar radiation per m2 per year is available, plants convert 1% of this energy to plant biomass, grasshoppers have 40% trophic efficiency, and cattle have 3% trophic efficiency.

Calculate the maximum possible biomass converted to plant biomass, to grasshopper biomass, and to cow biomass.

Assume that grasshopper meat and beef have a similar nutritional profile. If your goal is to use 1,000 hectares of grassland to support the maximum energy production for human consumption, should you raise grasshoppers or cattle?

Summative Assessment Questions:

  1. In a boreal forest, moose feed on aspen leaves and the primary predator feeding on moose’s the wolf. Let’s assume that moose have a trophic efficiency of 1% and wolves have a trophic efficiency of 3%. If 100,000 KJ of solar radiation hits aspen leaves, how much of this energy will eventually end up in new biomass of the wolf? To answer correctly, you need to remember the average percent of solar radiation that gets converted to NPP.

  1. 10,000
  2. 3,000
  3. 1000
  4. 300
  5. 3

  1. It is the year 2512, and moose have vanished from the earth due to the feeding preferences of the aliens who have landed and taken over. Wolves have adapted to feed on grasshoppers instead. Grasshoppers, as ectotherms, have lower maintenance energy. Predict the change in the energy converted into wolf biomass.

  1. It will increase.
  2. It will decrease.
  3. It will stay the same.

  1. Please explain why you chose the answer that you did.