Question
Q28. Which of the following are detritivores?
1. Earthworms
2. Jellyfish
3. Millipedes
4. Seahorse
5. Woodlice
Select the correct answer using the code given below.
A. 1, 2 and 4 only
B. 2,3,4 and 5 only
C. 1,3 and 5 only
D. 1,2,3,4 and 5
Answer: C
Detailed Explanation
Detritivores are the organism that feeds on detritus.
A detritivore is a heterotrophic organism, which obtains its nutrition by feeding on detritus.
Detritus is the organic matter made up of dead plant and animal material.
Detritivores may also obtain nutrition by coprophagy, which is a feeding strategy involving the consumption of faeces.
Detritivores are often invertebrate insects such as mites, beetles, butterflies and flies; mollusks such as slugs and snails; or soil-dwelling earthworms, millipedes and woodlice. Hence 1, 3 and 5 are correct.
A seahorse gains energy by eating other live organisms, meaning it is a carnivore.
A seahorse is not a decomposer because decomposers gain energy from breaking down dead organisms.
Jellyfish are carnivores and excellent predators. They sting with tentacles to subdue small aquatic fish and eat the eggs and invertebrates that stick to their tentacles. Hence 2 and 4 are not correct.
Extra:
Detritivores and decomposers contribute to the breakdown of all of the dead and decaying material in any ecosystem.
In this way, they play an important role in the cycling of nutrients and are an essential part of most biogeochemical cycles, such as the carbon cycle, nitrogen cycle and phosphorus cycle.
Examples of detritivores in marine environments are crustaceans such as crabs and lobsters, echinoderms such as sea stars or sea cucumbers.
Many of these marine detritivores occupy a similar niche to terrestrial soil-dwellers, living on or within the seabed known as the benthos.
