Chapter 31, Problem 44A

Summary Introduction

To Analyze:

The amount of energy that would be available to the fifth level of an energy pyramid if $41,900$ J represents $100$ percent of the energy at the producer level.

Introduction:

An energy pyramid is a graphical representation used to show the energy flow at the different trophic levels of an ecosystem. The width of every level represents the units of energy available in that particular trophic level, the height is the same always. It shows the production of biomass at each trophic level.

Explanation of Solution

      Figure 1

As per the $10\%$ rule of energy transfer if the producer has $41,900$ J of energy at the producer level. Then $10\%$ of it will move to the first tropic level.

  $\begin{array}{l}10\%of41,900\\ \frac{41900}{100}\times 10=4190\end{array}$

Then $10\%$ of it will move to the second tropic level.

  $\begin{array}{l}10\%of4190\\ \frac{4190}{100}\times 10=419J\end{array}$

Then $10\%$ of it will move to the third tropic level.

  $\begin{array}{l}10\%of419\\ \frac{419}{100}\times 10=41.9J\end{array}$

Then $10\%$ of it will move to the fourth tropic level.

  $\begin{array}{l}10\%of41.9\\ \frac{41.9}{100}\times 10=4.19J\end{array}$

Then $10\%$ of it will move to the fifth tropic level.

  $\begin{array}{l}10\%of4.19\\ \frac{4.19}{100}\times 10=0.419J\end{array}$

Conclusion

So, $0.419J$ of energy is moved to the fifth tropic level.