B18.8 Trophic levels and biomass

A pyramid of numbers

The number of organisms in a food chain can be represented graphically in a pyramid. Each bar represents the number of individuals at each trophic level (feeding level) in the food chain.

In this example, a large number of caterpillars living in a single oak tree provide food for several blue ****, which in turn are consumed by a sparrowhawk.

The pyramid of numbers usually shows that the number of organisms at each trophic level gets smaller towards the top. This particular case is an exception – one tree provides food for many caterpillars.

It usually takes a large number of plants to provide sufficient energy for the consumers in the food…