Question

Explain why a progressive decline is seen in the population size from the first to the fourth trophic level in the above pyramid.

 

 

Answer 1

In the above example, the primary producers can support less number of primary consumers, which in turn support lesser number of secondary and tertiary consumers. In a food chain, as the size of an organism at any trophic level increases, its number decreases. This happens because according to the 10% law, only 10% of the energy is transferred from one trophic level to the next. So in order to sustain life, the number of organisms keeps decreasing at each trophic level. Thus, there is a progressive decline in the population size from the first to the fourth trophic level in the above pyramid.