Chapter 3 · Try it yourself
The Energy Pyramid
Kelp and phytoplankton catch sunlight and turn it into food. Every time something eats something else, most of that energy is lost, burned up swimming, breathing and staying warm. Start with a million units of energy and see how much makes it to the top.
5% to 20%. About 10% is the classic rule of thumb.
Bar widths
The pyramid (choose a level to meet who lives there)
Energy that reaches a great white
100 of every 1,000,000 units
Simplified model: the same efficiency at every step, and each animal eats from only the level just below it. Real food webs are tangled: sea lions eat both anchovies and salmon, and whales skip straight to krill.