Question

(i) Compare the two ecological pyramids of biomass I and II given below and explain the situations in which this is possible.

(ii) Construct an ideal pyramid of energy if 2,00,000 joules of sunlight are available.

Answer 1

(i) Figure I is an upright pyramid of biomass, typical of a terrestrial ecosystem. Here, producers like trees and shrubs have a large biomass, followed by herbivores, then carnivores, showing a gradual decrease at higher trophic levels.

Figure II is an inverted pyramid of biomass, commonly seen in aquatic ecosystems. Phytoplankton have a very low standing biomass, but they reproduce rapidly and support a much larger biomass of zooplankton and fishes. Hence, biomass at higher trophic levels is larger than that of producers.

(ii)