Nat 5 Biology Unit Three Life On Earth Key Area 4 Energy in ecosystems

As heat, by movement an in undigested materials

90% of energy is lost, 10% retained Growth (10%) Undigested materials (60%) Heat and movement (30%)

It represents the number of organisms at each trophic level. Producers at the base, Primary consumers above, followed by secondary consumers and tertiary consumers at the top. The length of each bar proportional to the number of individuals at the level. A Pyramid of Numbers may have an irregular shape when the number producers is less than the number of props art consumers e.g. One Oak tree feeds on hundreds of Aphids and Caterpillars etc.

It shows the quantity to energy stored in the biomass of the organisms at each level in the food chain. Because energy is always lost between each level of food chain, a Pyramid of Energy always has a regular pyramid shape.