It is because of the 10% rule in the ecosystem, there are generally less biomass at the top.
The energy transfer in ecosystems:
It is found that only 10% of the energy stored as biomass in a trophic level is carried forward to the next trophic level. This is called the 10% rule, due to this rule, the number of trophic levels an ecosystem can support is limited.
As one goes up in the food chain, only 10% of the energy is passed on to the next level, that is, about 90% of the energy is lost in the form of heat. At the bottom of the trophic level, there are producers, that is, plants, they get their energy from the Sun.
Further the plants are consumed by the primary consumers, and the energy is passed on. However, in the process, only 10% of the energy is passed on and the rest is lost in the form of heat. Further the primary consumer is consumed by the predator, which comes at the top of the food chain.
During the consumption of primary consumer, the same 10% energy is passed on and the rest is lost. This process continues and the energy is lost in the form of heat. With less energy at the top of the trophic level, only few individuals can be supported. This is the reason of less predators in comparison to prey.
Thus, it is the 10% rule, which results in lesser number of tertiary consumers in comparison to producers.
Find out more information about energy transfer in ecosystems here:
https://brainly.com/question/21786633
