Q.6 Describe types of Ecological Pyramids.
Answer:
Definition
Ecological pyramid can be defined as, “A representation of the number of individuals or amount of biomass or energy present in various trophic levels of a food chain”.
Explanation
In 1927, Charles Elton (an English ecologist) developed the concept of ecological pyramids. He noted that the animals present at the beginning of food chain are abundant in number while the animals present at the end of food chain are fewer in number.
Types of Pyramids
Ecological pyramids are of three types:
1) Pyramid of Numbers
It is the graphic representation of the number of individuals per unit area at various trophic levels of a food chain.
Example
Usually, producers are present in large number, primary consumers are in lesser number, and secondary consumers are fewer. So, the producers are of smallest size but maximum in number, while the tertiary consumers are larger in size but lesser in number.

2) Pyramid of Biomass 
It is the graphic representation of biomass present per unit area at various trophic levels of a food chain. Example
In a terrestrial ecosystem, the maximum biomass is of producers and there is progressive decrease in biomass from lower to higher trophic levels.
Biomass
The total amount of living or organic matter in an ecosystem at any time is called “biomass”.

3). Pyramid of Energy
It is a graphic representation of energy present in a biomass of living organisms at various trophic levels of a food chain.
Example
The amount of energy is decreased from producers to decomposers as some amount of energy is used by the organisms to perform work while some of it is lost.