Question

Which of the following statements is false?

(i) The lower the trophic level at which an organism feeds, the lesser is the energy available.
(ii) All organisms that are not producers are consumers.
(iii) A single organism can feed at several trophic levels.
(iv) Detritus feeders, e.g., earthworms, feed at all trophic levels except the producer level.
a. (i) and (iii)
b. (ii) and (iv)
c. (i) and (ii)
d. (ii) and (iii)

Answer 1

The false statements in the question are (i) and (ii). The lower the trophic level, the more energy is available, and there are decomposers in addition to producers and consumers in ecosystems. The correct option is C.

Step-by-step explanation:

The correct answer is c. (i) and (ii).

Statement (i) is false because the lower the trophic level, the more energy is available. Energy decreases with each step up in trophic level, as outlined in the energy pyramid concept. This is due to the fact that, on average, only about 10% of the energy at one trophic level is passed up to the next level, with the other 90% being used for metabolism, growth, or lost as heat.

Statement (ii) is also false because, in addition to producers and consumers, there are decomposers (like fungi and bacteria) in an ecosystem that break down dead organic material, forming a distinct category separate from consumers.

Statement (iii) is true as a single organism, such as humans, can indeed feed at multiple trophic levels. For example, humans can be primary consumers when eating plants, secondary consumers when eating herbivores, and tertiary consumers when eating carnivores like fish that themselves eat other fish.

Statement (iv) is true because detritus feeders primarily consume dead organic material, which comes from all trophic levels except for producers, who are the living autotrophs.