Ecological Pyramids :
The ecological food chain consists of many food levels or tropic levels i.e. each tropic level is a step of food chain and many tropic levels are associated to each other.
The ecological pyramid is a graphical representation designed to show the biomass or bio productivity at each tropic level in a given ecosystem. The concept of pyramid was first given by Charls Elton (1927). Hence, they are also called as Elotonain Pyramids. The pyramids are triangular in shape (Pyramidal shape). The ecological pyramids are of three types viz.
(A) Pyramids of Number :
They represent number of organisms at each tropic level. They show that the number of large organisms is always less than the small organisms. These pyramids may be upright (eg. Grass land ecosystem) or inverted (eg. Parasitic ecosystem).
(B) Pyramids of Biomass :
Biomass is the amount of organic matter present in an organism. It shows how much biomass is present in the organisms of each tropic level. They may be upright (eg. Grassland ecosystem, Forest ecosystem, Crop field ecosystem) or inverted (eg. Aquatic ecosystem).
(C) Pyramids of Energy :
They shows the flow of energy through the food chain. The energy pyramids begins with the producers and ends in the top level of the food chain. They are always upright, as flow of energy is gradually reduced at every tropic level.
