This memory aid covers Memory Aids for Ecosystems within Ecosystems Overview for GCSE Geography. Revise Ecosystems Overview in The Living World for GCSE Geography with 15 exam-style questions and 16 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 13 of 16 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
Topic position
Section 13 of 16
Practice
15 questions
Recall
16 flashcards
🧠 Memory Aids for Ecosystems
BLEND — The Five Components of an Ecosystem
- B — Biotic (living: plants, animals, fungi, bacteria, decomposers)
- L — Links (food webs, energy flow, feeding relationships)
- E — Energy (flows in one direction; 10% passes between trophic levels)
- N — Nutrient cycling (three stores: Biomass, Litter, Soil)
- D — Distribution (biomes: controlled by latitude, precipitation, ocean currents, altitude)
The 10% Rule — Visualised
Picture a leaky bucket. You pour in 10,000 kJ of sunlight. The bucket has a hole — 90% leaks out at each pour. After the first pour into the grasshopper, only 1,000 kJ remains. Pour again into the frog: 100 kJ. Pour into the snake: 10 kJ. Pour into the hawk: 1 kJ. After four links, you have only one ten-thousandth of the original energy. That is why food chains end — not because predators run out of space, but because they run out of energy.
BLS — The Nutrient Cycle Stores
Remember the three stores as BLS: Biomass → Litter → Soil. Nutrients flow: living things die (B→L), decomposers break them down (L→S), plants absorb nutrients through roots (S→B). The cycle restarts. In a TRF: giant B, tiny L, tiny S. In a desert: tiny B, tiny L, medium S.
LAODA — Why Biomes Are Where They Are
- Latitude (distance from equator → controls temperature)
- Atmospheric pressure belts (rising air at equator = rain; descending air at 25–30° = desert)
- Ocean currents (Gulf Stream warms NW Europe; cold currents create fog deserts)
- Distance from sea / continentality (coasts = moderate; interiors = extreme)
- Altitude (temperature falls 6.5°C per 1,000 m)