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MODEL PAPER 7 — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceMODEL PAPER 72 Marks
Question
i. Construct a terrestrial food chain comprising four trophic levels.
ii. What will happen if we kill all the organisms in one trophic level?
iii. Calculate the amount of energy available to the organisms at the fourth trophic level if the energy available to the
organisms at the second trophic level is 2000 J.
✓

Answer

Gross $\longrightarrow$ Rabbit $\longrightarrow$ Wolf $\longrightarrow$ Tiger
b. If all organisms of any one trophic level are killed then its previous trophic level organisms will increase in number to such an
extent that their previous trophic level will also become extinct and the next trophic level organisms will also get extinct. For
e.g., if we remove all wolves then rabbits will increase and will eat up all the grass, at the same time tigers will also perish
because of lack of their food.
c. Energy is transferred as per 10% law : Hence, if energy available at second trophic level is 2000 J then third trophic level will
have
$\frac{10}{100} \times 2000=200 J$ and fourth trophic level will have $\frac{10}{100} \times 200=20 J$

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