Question

A pasture of 40 hectares has a biomass of 40 kg/hectare, or roughly 1,000,000 calories of energy. Cattle grazing on this pasture are sold for beef. How many calories of energy from the pasture reach human consumers of the beef?
A.10,000
B.1000
C.100,000
D.1,000,000

Answer 1

Hint: A pasture is an area of land covered with grass so that cattle such as cows etc. can graze on it. It is also known as grassland or a meadow. Shrubs, bushes and plants constitute a pasture land. These lands serve as forage for different types of domestic livestock.


Complete step by step solution:
Cattle grazing on pastures or grasslands gain energy according to the distribution of energy in trophic levels. This energy then gets transferred to the consumers of these cattle in accordance with the same law of energy distribution in trophic levels.

Biomass is a unique, renewable source of energy where organic matter of plants and animals such as agricultural products, animal manure, wheat or barley straw etc are used to generate electricity or heat energy. A certain area of pasture land can produce a considerable amount of biomass.

In the ecosystem, organisms feed on each other and transfer of energy takes place. The law of distribution of energy is such that, only 10% of energy in the previous trophic level gets transferred to the next level.

Hence, the amount of calories of energy that will reach the consumers of beef will be only 10% of 1,000,000 i.e.100,000 calories of energy.

Note:
 In any food chain, energy is transferred among the various trophic levels but not all the energy goes to the subsequent levels. Only 10% of energy is transferred from one trophic level to another. The rest of the energy is lost in metabolic processes occurring in organisms in the form of heat.