The pond's energy budget
In a pond, algae capture sunlight, tiny shrimp eat the algae, and fish eat the shrimp — each level passing on only a sliver of the original energy. Trace that flow and you see why the pond can feed swarms of shrimp but only a handful of big fish.
Follow the energy
Energy enters an ecosystem from the Sun. Producers (plants) capture it; herbivores eat plants; carnivores eat herbivores. Each step is a trophic level, and only about 10% of energy passes to the next level — the rest is lost as heat.
grass → grasshopper → frog → snake (each arrow ≈ 10% energy passed on)
Lab · Build a food chain
- Start with the Sun and a producer (grass).
- Add a herbivore, then a carnivore.
- At each arrow, note that most energy is lost.
What you should see: Because ~90% of energy is lost per step, food chains rarely have more than 4–5 levels.