A pyramid of biomass is a graphical representation of biomass present in a unit area of various trophic levels. [½ mark]
The pyramid of biomass can be inverted or upright. In aquatic ecosystem the mass of the producers, will always be lower than the mass of the heterotrophs like fish and insects. So, the pyramid of biomass is inverted. [½ mark]
In terrestrial ecosystem, the pyramid of biomass is upright since the producers or the green plants have more biomass than the consumers. [½ mark]
A pyramid of energy is a graphical representation of energy present in a unit area of various trophic levels. [½ mark]
Pyramid of energy is always upright. As energy flows from one trophic level to the next trophic level some amount of energy is lost in each trophic level in the form of heat. Therefore, the pyramid of energy is always upright and can never be inverted. [1 mark]