Biomass, in ecology, is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms, plants or animals. The mass can be expressed as the average mass per unit area, or as the total mass in the community.
An ecological pyramid is a graphical representation which shows, for a given ecosystem, the relationship between biomass or biological productivity and trophic levels.
A biomass pyramid shows the amount of biomass at each trophic level.
A productivity pyramid shows the production or turn-over in biomass at each trophic level.
An ecological pyramid provides a snapshot in time of an ecological community.