(a) By an ecological pyramid, trophic structure can be redescribed. The interaction of food chain and the size and metabolism relationship between the linearly arranged various biotic components of an ecosystem is characteristic of each type of ecosystem.
For example : In a pond ecosystem, small phytoplanktons are served as producer. These are taken by zooplanktons; these are in small number than phytoplanktons. Zooplanktons are eaten by small fishes and in turn small fishes are eaten by big fishes. Therefore, the number of individuals successively reduces from phytoptanktons to big fishes. It makes a pyramidal structure.
(b) Pyramid of energy is always upright as only 10% energy is transferred from one trophic level to the next. Inverted pyramid shows less number/ biomass of producers when compared to primary consumers.
