Question

On an average, the proportion of assimilated energy consumed by herbivores in respiration is

• A. 10%
• B. 20%
• C. 30%
• D. 60%

Answer 1

The correct option is C 30%

The energy assimilated by the herbivores is used in respiration and a fraction of unassimilated energy is transferred to decomposers. The herbivore level of energy either utilized by the carnivores or gets transferred to decomposers after the death of herbivores. In this way, again only a small fraction, that is about 10% of herbivore productivity is used to support carnivore productivity. In the same way, the energy available at carnivore trophic level is again divided, leaving a very small fraction to support the next trophic level, that is, top carnivore.

With increasing trophic levels, the respiration cost also increases sharply. On an average, producers consume about 20% of their gross productivity in respiration. The herbivores consume about 30% of assimilated energy consumed in respiration rises to about 60%.

Thus, there is a tremendous loss of energy at successively higher trophic levels.

So, the correct answer is option C.