Consider the following food chains:

(i) Plants Mice Snakes Hawks


(ii) Plants Mice Hawks


If energy available at the producer level in both the food chains is 100 J, in which case will hawks get more energy as food and by how much? Justify your answer.

i) Plants—Mice—Snakes—Hawks.


If 100J is available at producer level (plants); mice will receive 10% of it- 10J.


10% of energy transfer will take from mice to snakes. 10% of 10J=1J. Snake will receive 1J of energy.


10% of energy will be transferred from snake to hawks. 10% of 1J=0.1J. Hawk will receive 0.1J of energy in this food chain.



ii) Plants—Mice—Hawks.


If 100J is available at producer level (plants); mice will receive 10% of it-10J


10% of 10J energy will be transferred from mice to hawks. 10% of 10J=1J.


The Hawks will receive 1J energy in this food chain.



Therefore, hawks will get more energy in the food chain which is equal to 1J and is more than 10% than the energy it is receiving in the first food chain. This is because in the first food chain Mice were being eaten by snakes, and hawks had to eat snakes, so it received less energy. In the second food chain, hawks directly ate mice, there were no snakes to consume energy in between so hawks received more energy.


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