The graphical representation of certain characteristics of an ecosystem such as number, biomass and energy provide pictures with broad base and tapering apex and these constitute ecological pyramids or Eltonian pyramids. In ecological pyramids, producers occupy the base of the pyramid and top consumers occupy the apex of the pyramid. The pyramids are of three types, namely pyramid of numbers, pyramid of biomass and pyramid of energy.
- Pyramid of numbers is a pyramid constructed on the basis of number of individuals that occupy each tropic level in a given area of the ecosystem at a given period of time.
- Pyramid of biomass is a pyramid constructed on the basis of the total body weight (biomass) of individuals that occupy each tropic level.
- Pyramid of energy is a pyramid constructed based on the amount of energy available to each trophic level.