Question

A food web is a diagram that shows the interaction of organisms in an ecosystem. Which statement best describes the transfer of energy in a food web?


The amount of energy transferred at each trophic level decreases because some is lost as heat.


The amount of energy transferred at each trophic level is the same because energy is conserved in a system.


The amount of energy transferred at each trophic level increases because the size of the organisms increases.


The amount of energy transferred at each trophic level is different in land and marine ecosystems because the animals are different.

Answer 1

The correct answer is A. The amount of energy transferred at each trophic level decreases because some is lost as heat.

Explanation:

In food webs and food chains, there are different trophic levels, this includes producers such as plants, primary consumers such as herbivores, tertiary consumers such as carnivores, among others. These levels are closely related in terms of energy as most organisms obtain energy by consuming others at a lower trophic level. For example, herbivores such as rabbits obtain energy by consuming plants (producers).

However, the energy transferred at each trophic level is lower than the total energy and it decreases at each trophic level, this occurs because part of the energy is lost as heat due to biological processes such as cellular respiration. Thus only about 10% of the energy is transferred.