Safety and evidence boundary
Use supplied ecological datasets, safe non-contact observation, and paper/digital food-web models. Do not disturb wildlife or reveal sensitive species locations. Energy-flow models are ecosystem approximations and should include units, area/time scales, and uncertainty.
Explicit science instruction
Energy enters food webs through producers and moves through consumers and decomposers. Ecological efficiency can be calculated as energy transferred to the next trophic level divided by energy available at the previous level ×100%.
Transfer varies because organisms differ in consumption, digestion, metabolism, temperature regulation and tissue composition.
Worked example with reasoning
Producer production=10,000 kJ; primary consumer production=1,200 kJ. Efficiency=12%. If secondary consumer production=96 kJ, next efficiency=8%. The two transfers need not match.
Guided question
Why is fixed 10% transfer a useful classroom approximation but a poor universal law?
Independent work
- Calculate three transfer efficiencies.
- Compare energy and biomass pyramids.
- Explain heat loss and uneaten material.
- State one aquatic exception in biomass shape.
Misconception check
Energy is not recycled indefinitely through trophic levels; usable energy degrades and dissipates as heat while matter cycles.
Formative understanding check
600 kJ from 5,000 kJ = what efficiency?
Worked response
12%.
Open-book formative practice only; not an official mastery attempt or grade.
Mentor evidence conference
Ask Archaemenes to challenge your model topology, evidence classification, calculation, and stated uncertainty without substituting belief or protected answers for science mastery.
Open ArchaemenesTeacher guidance
Foundation: use arrow-width energy diagrams. Core: calculate variable efficiencies. Extended: compare production efficiency among ectotherms/endotherms conceptually.
Preserve learning evidence
Keep models, data work, corrections, source classifications, and limitations in the matching Week 31 evidence field.