Free response · Unit 1 Beta

Energy flow in a grassland reserve

Q3: Analyze an environmental problem with calculations · scientific calculator allowed · 10 points

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The question

Name: ______________________   Date: ____________   Energy flow in a grassland reserve (10 points)

Data

Producer data for a grassland reserve

Measurements for the producers of a 3 km² grassland reserve (invented data for practice). 1 km² = 1,000,000 m².
MeasurementValue
Gross primary productivity (GPP)6,000 kcal/m²/yr
Energy used by the producers in respiration (R)3,000 kcal/m²/yr
Area of the reserve3 km²
Food chaingrasses → grasshoppers → meadowlarks → hawks

  1. (a) Calculate the net primary productivity (NPP) of the grassland. Show your work and include units. [2 points]

  2. (b) Using your answer to part (a) and the 10% rule, calculate the energy available to the meadowlarks. Show your work and include units. [2 points]

  3. (c) Calculate the total energy available to the meadowlarks in the whole 3 km² reserve each year. Show your work and include units. [2 points]

  4. (d) Explain why only about 10% of the energy in the grasshoppers is available to the meadowlarks. [2 points]

  5. (e) A rancher proposes removing the hawks from the reserve. Describe the most likely effect on the meadowlark population, and explain one effect this could have on the grasshoppers. [2 points]