Define ecological pyramids and describe with examples, pyramids of numbers and biomass.

Ecological pyramid is a graphical representation of the trophic structure and function of an ecosystem, first represented by Elton. There are three types of pyramids.

• Pyramid of numbers
• Pyramid of biomass
• Pyramid of energy

Pyramid of number: It represents number of organisms at each trophic level. The typical pyramid of numbers is upright, but pyramid of numbers in parasitic food chain is inverted.
 

Pyramid of Biomass: Biomass is the dry weight of organisms. This pyramid indicates the biomass of each trophic level in a food chain. The typical pyramid of biomass is upright, but in aquatic ecosystem it is inverted.