Question

Across trophic levels, energy flows from producers to primary consumers, and from primary consumers to secondary consumers. Which one of the following options best represents the percentage of energy that is transferred from producers to secondary consumers?

• A. Between 0.01 and 0.02 %
• B. Between 0.5 and 1.5 %
• C. Between 7.5 and 12.5 %
• D. Between 72.5 and 77.5 %

Hint:

When considering energy transfer in ecosystems, remember that energy loss increases with each trophic level, with only a small fraction transferred to higher levels.

Answer 1

The Correct Option is B

Step 1: Energy transfer across trophic levels.
The transfer of energy across trophic levels typically follows the 10% Rule, which states that only about 10% of the energy at one trophic level is passed on to the next. So, if energy is transferred from producers to primary consumers (10%) and then to secondary consumers (10% of that), only about 1% of the original energy from producers is available to secondary consumers.

Step 2: Explanation of the other options.

• Option (A): Too small — underestimates the energy passed on after two trophic steps.
• Option (C): Too high — doesn't account for energy lost at each level due to heat, respiration, and metabolic processes.
• Option (D): Represents 100% of the energy captured by producers and is not relevant to energy passed on to secondary consumers.

Conclusion: The correct answer is Option (B): 1%, representing the typical energy passed from producers to secondary consumers via primary consumers.