Question

The pyramid of ________ is always upright and can never be inverted.

Hint:

Thermodynamics dictates that energy flow is unidirectional and dissipative; hence energy pyramids can {never} be inverted.

Answer 1

Step 1: Understanding the Concept:
Ecological pyramids represent the relationship between trophic levels in an ecosystem.
Step 2: Detailed Explanation:
The pyramids of numbers and biomass can sometimes be inverted (e.g., in a single large tree supporting many insects or biomass in marine ecosystems).
However, the pyramid of energy is always upright.
This is because according to the second law of thermodynamics, energy is lost as heat at every trophic level transfer.
Typically, only 10% of the energy is transferred to the next higher level. Thus, the energy at a lower level is always greater than the energy at a higher level.
Step 3: Final Answer:
Pyramid of energy.