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IB ESS HL 2.2.28 Hl Ecological Efficiency Questions

Calculate ecological efficiency from trophic-level energy data, then interpret variable transfer rates and compare terrestrial and aquatic food-production systems.

Syllabus
First assessment 2026
Course
ESS HL
Level
HL

Exam points

  • calculate ecological efficiency as energy passed to the next trophic level ÷ energy received × 100
  • interpret variable efficiency values across trophic levels, species or ecosystems and reject a fixed 10% assumption
  • discuss terrestrial and aquatic food-production efficiency using trophic losses and energy-conversion evidence

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Study 2.2.28 (HL)—Ecological efficiency conceptsOpen the corresponding Concept lesson for explanations, examples and exam connections.

IB ESS HL 2.2.28 Hl Ecological Efficiency Questions question 1

[Maximum number: 1]
Figure A sample food chain from a marine ecosystem to show the concentration of persistent organic pollutants (POPs) and the energy within each trophic level

Figure A sample food chain from a marine ecosystem to show the concentration of persistent organic pollutants (POPs) and the energy within each trophic level

Calculate, as a percentage, the efficiency of energy transfer between zooplankton and herring.

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