Chapter 54, Problem 1TYK

Summary Introduction

Introduction:

Food chain is a path through which nutrients and energy move through the ecosystem. Food web is a network of linked/interconnected food chains in an ecosystem. Food web consists of trophic levels based on feeding habits of organisms. Primary producers form the first trophic level of food chain, herbivores form the second level, and carnivores feeding on herbivores are present on the third trophic level. Detritivores and decomposers link all trophic levels.

Answer to Problem 1TYK

Correct answer:

When a robin catches and eats an earthworm, it will transfer the energy and nutrients from detritivores to the higher trophic level.

Explanation of Solution

Justification/explanation for the correct answer:

Option (c) states that when a robin catches and eats an earthworm, it transfers energy and nutrients from the detritivores level to the higher trophic level. This is correct because earthworm is a detritivore that feeds on wastes of other organisms. In the given case, Robin is a carnivorous bird and belongs to a higher trophic level. Thus, when a robin catches and eats an earthworm, energy and nutrients from a detritivore gets transferred to a higher trophic level. Hence, option (c) is correct.

Explanation for the incorrect answers:

Option (a) states that when a beetle eats the leaves of a living plant, it transfers energy and nutrients from the detritivores level to a higher trophic level. This is incorrect because living plants are the producers belonging to the first trophic level. When beetle eats the leaves of a living plant, energy and nutrients gets transferred from first trophic to the second trophic level. So, it is an incorrect option.

Option (b) states that when an earthworm eats dead leaves on the forest floor, it transfers energy and nutrients from the detritivores level to the higher trophic level. This is incorrect because here earthworm is getting energy and nutrients from dead leaves, which are wastes from plants or producers, and not from a detritivore. So, it is an incorrect option.

Option (d) states that when a falcon eats a robin, it transfers energy and nutrients from the detritivores level to a higher trophic level. This is incorrect because falcon is a carnivore that is, it gets energy and nutrients from robin, which is also a carnivore and not a detritivore. So, it is an incorrect option.

Option (e) states that when a bacterium decomposes the feces of an earthworm, it transfers energy and nutrients from the detritivores level to a higher trophic level. This is incorrect because the bacterium belongs to decomposers and is not a part of higher trophic level. So, it is an incorrect option.

Hence, options, (a), (b), (d), and (e) are incorrect.

Conclusion

Thus, it can be concluded that when a robin catches and eats an earthworm, energy and nutrients from a detritivore gets transferred to a higher trophic level. In this case, the earthworm is a detritivore, while the Robin is a carnivore.