A food-chain arrow points from food to eater. It represents transfer of matter and chemical energy. Sunlight is an energy input, not an organism. Organisms use energy, and some spreads as heat; not all energy reaches the next consumer. Safety: Use written organisms only; do not feed or remove wildlife. Stop: Stop after the revised prediction; no feeding experiment or population test is needed.

Materials: Paper; Pencil 1. Write four illustrative woodland-edge cards: oak leaf; leaf-eating caterpillar; caterpillar-eating small bird; bird-eating hawk. Write each food link exactly as given. Arrange them from producer to top consumer. 2. Draw oak → caterpillar → small bird → hawk. Add sunlight → oak separately. Label oak producer, caterpillar primary consumer, and bird and hawk predators. Mark the prey for each predator. 3. Beside each animal, draw a small heat arrow leaving the chain. Write why a food chain does not pass all its incoming energy to its last animal. Do not invent a fixed transfer percentage. 4. Cross out caterpillars on a second copy. Write one likely pressure on birds and one possible effect on oak leaves if these were the only feeding links. Then add: birds can eat other insects. Revise the certainty of your prediction. Done: There is one correct four-organism chain, producer and predator/prey labels, and a qualified removal prediction. Proof: Keep both chain versions and the revised prediction. Record any adult help with arrow direction or the meaning of primary consumer. Stop: Stop after the revised prediction; no feeding experiment or population test is needed.