In 1927, Charles Elton of England observed that the animals at the base of the food chain are relatively abundant than the animals at the end of the food chain. In other roads, he observed a progressive decease in the number of consumers in the food chain. It is so because at each step with food chain a considerable portion of the potential energy is lost as heat. As a result organization in each trophy level pas on lesser energy in the next trophy level than they actually receive. There are different types of ecological pyramid such as - pyramid of numbers, pyramid of biomass and pyramid of energy. Pyramid of numbers refers to the number of individuals in each trophy level. Pyramid of biomass indicates the decrease of biomass in each trophy level from base to apex. The pyramid of energy not only the amount of total energy utilized by the organism at the each trophy level of food chain but more important the actual role of various organisms in transfer of energy.