In the following food chain, vertical arrows indicate the energy lost to the environment and horizontal arrows indicate energy transferred to the next trophic level. Which one of the three vertical arrows (A, C and E) and which one of the two horizontal arrows (B and D) will represent more energy transfer? Give reason for your answer.

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A will represent more energy transfer as compared to C and E. 

B will represent more energy transfer as compared to D. 

When green plants are eaten by primary consumers, a great deal of energy is lost as heat to the environment, some amount goes into digestion and in doing work and the rest goes towards growth and reproduction. An average of 10% of the food eaten is made available for the next level of consumers. This loss of energy takes place at every trophic level. 

Alternatively accept - In accordance with 10% law of transfer of energy in a food chain only 10% of energy available at one trophic level is transferred to the next trophic level.


According to 10% Law

Only 10% energy available at particular trophic level is available for transfer to other trophic level

Remaining 90% energy is reflected back to the environment


Now in our question

There are 3 trophic level

Plants ------> Deer -------> Tiger

Suppose energy available with Plant is 100 joules

Out of this, only 10% of 100=10 joules will be transferred to Deer

Remaining 90 Joules will be reflected back to the environment




Now, energy available with Deer is 10 Joules

Out of this ,Only 1 Joule is transferred to Tiger

Remaining 9 joules is lost to the environment



D= 1

Now, coming to tiger, he has 1 Joule energy

Out of this,90% will be lost to environment =90%*1=0.9

So E=0.9

Comparing Vertical arrows




Hence, A has highest energy lost to environment

Comparing Horizontal Rows



B has highest energy transfer'


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CA Maninder Singh is a Chartered Accountant for the past 14 years and a teacher from the past 18 years. He teaches Science, Economics, Accounting and English at Teachoo