The energy pyramid below represents the trophic levels in a food web.
image c648e61eab1d4c9f9d1b7beee4239cee
Assume that the producers in this ecosystem have 100,000 kcal of stored energy.
About how much of this energy would reach the tertiary consumers in the ecosystem?
a
100 kcal
b
1000 kcal
c
70,000 kcal
d
73.000 kcal
The correct answer is c) 70,000 kcal.
In an energy pyramid, energy is lost as it moves up each trophic level. Typically, only about 10% of the energy from one trophic level is transferred to the next trophic level. This is known as the 10% rule.
In this scenario, if the producers have 100,000 kcal of stored energy, the primary consumers would receive about 10% of this, which is 10,000 kcal. The secondary consumers would then receive about 10% of the energy from the primary consumers, which is 1,000 kcal. Finally, the tertiary consumers would receive about 10% of the energy from the secondary consumers, which is 100 kcal.
Therefore, about 100 kcal of the original 100,000 kcal of energy would reach the tertiary consumers in the ecosystem.