Read Energy Transfer One Trophic Step at a Time
Energy enters ecosystems mainly as sunlight, is captured by producers, and moves one-way through trophic levels.
Living-system questions are solved by matching a structure or organism to its function, process and stated condition.
Calculate transfers
Only a fraction of incident solar energy is captured by producers. Under the 10% rule, about one-tenth of energy at one trophic level becomes available to the next. Apply the fraction repeatedly to estimate energy at consumers.
Explain direction and loss
Energy flows one way and dissipates as heat at each transfer. The first law states energy is conserved; the second law explains why not all energy remains available for work or the next level. Productive ecosystems support more energy across trophic levels.
Read energy arrows and heat loss
Sunlight reaches producer A; B is the first consumer, C the secondary consumer, and D the higher consumer. Energy is lost as heat at each transfer. Lindeman's 10% rule does not apply to sunlight capture by A, but both thermodynamic laws still apply. Producers are indispensable, yet a functioning ecosystem also depends on decomposers and abiotic conditions.
OlympIQ exam lens
- ✓Solar input → producers → consumers.
- ✓10% rule: multiply by 0.1 per step.
- ✓Flow is unidirectional.
- ✓Second law explains energy loss as heat.
Do not apply the 10% rule to the share of sunlight captured unless the stem explicitly says so.
Ready to try the pattern?
100% coverage across the 6 linked questions.
Practise 6 linked questions