The net primary production of all producers in the ecosystem is 5 tons. One kilogram of phytomass contains 800 kcal of energy.

The net primary production of all producers in the ecosystem is 5 tons. One kilogram of phytomass contains 800 kcal of energy. Calculate the maximum number of first-order consumers that can feed in a given ecosystem, if their average weight is 4 kg, 100 g of their body contains 500 kcal of energy. The transition of energy from one level to another occurs in accordance with the Lindemann rule.

5 tons = 5000 kg
Ecosystem energy intensity:
5000 kg x 800 kcal = 4,000,000 kcal
Energy intensity of consumers (consumers of the 1st order):
4000 g (4 kg) x 5 kcal (500 kcal / 100 g) = 20,000 kcal
Assimilated from the ecosystem: 10% of 4,000,000 = 400,000 kcal
The ecosystem will be able to feed: 400,000 kcal: 20,000 kcal = 20 individuals