4.5c Pyramids

There are 3 different types of food pyramids:

-Pyramids of number

-Pyramids of biomass

-Pyramids of energy transfer

Pyramids of number:

These pyramids illustrate the number of organisms per trophic level, however there are problems with using this method. The pyramids sometimes goes against the laws of thermodynamics and fails to show the energy transfer between trophic levels. They can be effective but are highly limited.

Pyramids of biomass:

Bio=living and mass=g/kg

Biomass is based on dry mass and tends to be measured in kg/area. It is difficult to find out the dry biomass of each organism per trophic level.

Pyramids of energy transfer:

This measures the movement of energy from on trophic level to another. It follows the laws of thermodynamics and cannot be inverted. It is measured in Joules or KJ/m squared/time (seconds/minutes/years). This method is also extremely hard to calculate.