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Ecosystems

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Question 25

An ecologist investigated the energy transfer in a population of primary consumers (caterpillars) in a woodland ecosystem. The energy values recorded for this population over one year were:

  • Energy in ingested food (III) = 2.40×105 kJ m−2 yr−12.40 \times 10^5 \text{ kJ m}^{-2}\text{ yr}^{-1}2.40×105 kJ m−2 yr−1
  • Energy lost in faeces and urine (FFF) = 1.32×105 kJ m−2 yr−11.32 \times 10^5 \text{ kJ m}^{-2}\text{ yr}^{-1}1.32×105 kJ m−2 yr−1
  • Net production (NNN) = 1.80×104 kJ m−2 yr−11.80 \times 10^4 \text{ kJ m}^{-2}\text{ yr}^{-1}1.80×104 kJ m−2 yr−1

What percentage of the energy ingested by these primary consumers is lost as heat to the surroundings due to cellular respiration?

7.5%7.5\%7.5%

37.5%37.5\%37.5%

45.0%45.0\%45.0%

55.0%55.0\%55.0%

Ecosystems Questions

  1. A Level
  2. /Biology
  3. /Ecosystems