Question

using the 10% rule when studying trophic pyramids, if the secondary consumers at the third trophic level obtain 500 joules of energy, how much energy do the primary consumers have at the second trophic level? 5,000 joules 500 joules 50 joules

Explanation:

Step1: Understand the 10% rule

The 10% rule states that only about 10% of the energy from one trophic level is passed on to the next trophic level. So, if we know the energy at a higher - level trophic (in this case, secondary consumers at the third trophic level), we can find the energy at the lower - level trophic (primary consumers at the second trophic level) by using the formula \(E_{lower}=\frac{E_{higher}}{0.1}\)

Step2: Calculate the energy of primary consumers

We are given that \(E_{higher}\) (energy of secondary consumers) is \(500\) Joules. Using the formula \(E_{lower}=\frac{E_{higher}}{0.1}\), we substitute \(E_{higher} = 500\) into the formula: \(E_{lower}=\frac{500}{0.1}=5000\) Joules

Answer:

5000 Joules