Food chains involving various living organisms in a community can also be represented in a graphical manner by drawing pyramids called ecological pyramids. An ecological pyramid is the graphical representation of a specific parameter (such as number, biomass, and energy) of a food chain. Ecological pyramids have various levels. The producer level is represented by the base of the pyramid. And as the trophic level increase the pyramid goes on tapering upwards. The carnivores are on the top of the pyramid.
Biomass is the total weight of organisms per unit area. The graphic representation of biomass of organisms of the successive trophic levels of an ecosystem in the form of a pyramid is called pyramid of biomass. In most ecosystems the biomass at the successive higher levels decreases. For example, in a forest ecosystem, there is a gradual decrease in biomass of organisms at successive food levels from producers to the consumers.
In most of the ecosystems, the pyramid of biomass is upright. It is because of the biomass at the successive higher levels of the ecosystem decreases. For example, forest ecosystem. In a forest ecosystem, there is a gradual decrease in biomass of organisms at successive food levels from producers to carnivores.
In certain ecosystems, the pyramid of biomass is inverted .Example: deep water bodies. The pyramid of biomass for a lake ecosystem is inverted because, the biomass of a number of short –lived producers (standing crop of phytoplankton) at a particular time is less than the biomass of large standing crop of zooplankton.