Question

Which of the following statements about food chains are correct?
(a) Removal of 80% of tigers resulted in increased growth of vegetation.
(b) Removal of most carnivores resulted in an increased population of deer.
(c) Length of the food chain is limited to 3-4 trophic levels due to energy loss.
(d) Length of the food chain may vary from 2-3 trophic levels.

• A. a, d
• B. a, b
• C. b, c
• D. c, d

Answer 1

Answer: (C)

b, c

• In a food chain, the carnivores eat up herbivores, or in other words, the secondary consumers consume the primary consumers. So, we can say that if the number of carnivores decreases, the number of herbivores like deer go on increasing as they will not get eaten up. So, the removal of most of the carnivores will result in an increased population of deer.
• Apart from this, we also know that as we move from one tropic level to another, the amount of energy goes on decreasing. This is according to the 10% law according to which, at each trophic level, 10% energy is lost. So, each food chain is only 3-4 tropic levels long due to these energy losses.
  

Therefore, b and c are the correct statements.

So, the correct option is C.