Question

Which statement best explains the decrease in energy availability in a food chain?

Answer 1

Answer: The correct answer is D) Some energy in each trophic level is used for life processes.  

Food chain represents the flow of energy through various living organisms (which lie at different trophic levels) in an ecosystem. The energy flows from one trophic level to the next and it is decreased with subsequent trophic levels.

As per the law of 10% energy transfer, only 10 % of the energy is transferred from one level to the next as the rest of the energy at every trophic level is utilized in various metabolic processes like respiration, digestion, excretion and also liberated as heat in the surrounding.

Due to this, the energy available at any trophic level is less than the previous trophic level.

Answer 2

Answer: Option D

A. Organisms use almost all the energy they receive. False

Organism use 90 percent of the energy they get from the previous trophic level. The amount of energy transferred to next trophic level is only 10 percent.

B. There are fewer organisms at higher trophic levels. False

There are both upright and inverted pyramids. So the number of organisms can vary from one ecosystem/community to another. Thus, the number of organisms can’t be related to energy decrease.

C. There is less biomass at higher trophic levels. False

Same reason as above. The biomass amount can’t be related to energy decrease.

D. Some energy in each trophic level is used for life processes. True

Since some of the energy is lost for maintaining the life processes, less energy is available for the next trophic level.