Question

An ecological pyramid is sometimes used to show both the flow of matter and energy in an ecosystem. The pyramid narrows as matter and energy flow from the bottom to the top. What does this pyramid tell you about the energy in this ecosystem? A) Energy stays the same. Only the number of living things change. B) Energy decreases from the top to the bottom as organisms are larger in size. C) Energy increases from bottom to top because the organisms get larger in size. D) Energy decreases from bottom to top because some is used at each level for life processes.

Answer 1

Correct answer: D). Energy decreases from bottom to top because some is used at each level for life processes.

The pyramid of matter and energy in the ecosystem tells that when energy flows from one trophic level to another trophic level, then some amount of energy is always lost as a heat, which is lost to the atmosphere and it never comes back.

Therefore the primary consumers obtain 10% of energy from the autotrophs and secondary consumers get 1% of energy and that of tertiary consumers get 0.1%. It shows that top consumers receive the least energy. It is also called as10% law.

Answer 2

D
Organisms in each trophic level utilize the energy they have obtained and only about 10% from each trophic level is passed to the next.