What happens to the energy as it moves up the trophic levels in a food chain?

• A. Energy decreases at higher trophic levels.
• B. Energy increases at higher trophic levels.
• C. Energy is completely lost at higher trophic levels.
• D. Energy remains constant across trophic levels.

Answer: (A)

Verified step by step guidance

1. Begin by understanding the concept of trophic levels in a food chain. Trophic levels represent the hierarchical levels in an ecosystem, comprising producers at the base, followed by primary consumers, secondary consumers, and so on.
2. Recognize that energy transfer in a food chain is governed by the laws of thermodynamics, particularly the second law, which states that energy transformations are not 100% efficient.
3. As energy moves from one trophic level to the next, a significant portion of it is lost as heat due to metabolic processes. This is why higher trophic levels receive less energy than the levels below them.
4. Consider the energy pyramid model, which visually represents the decrease in available energy as you move up the trophic levels. The base of the pyramid is wide, indicating more energy available to producers, while the top is narrow, showing less energy available to top consumers.
5. Conclude that energy decreases at higher trophic levels because only a fraction of the energy is transferred from one level to the next, with the rest being lost primarily as heat.