Question

Which one is the detritus food chain?

• A. Grass → Insects → Snake
• B. All of the above.
• C. Organic matter → Bacteria → Molluscs
• D. Plankton → Small fish → Large fish

Answer 1

The correct option is C Organic matter → Bacteria → Molluscs

Introduction to the detritus food chain
The detritus food chain usually operates in soil or benthic zones where the first trophic level is made up of dead and decaying organic matter. The second trophic level is made up of microbes that are decomposers. They obtain energy by degrading complex organic matter formed by primary producers into simpler inorganic compounds.

Grass → Insects → Snake
The given food chain represents a grazing food chain as the first trophic level is occupied by grass which is a producer. The second trophic level is occupied by an insect that feeds on the grass and the third trophic level is occupied by a carnivorous snake that feeds on the insects.

Plankton → Small fish → Large fish
The given food chain is considered to be an oceanic food chain where the phytoplanktons are the producers, zooplanktons are the primary consumers, small fishes are the secondary consumers and large fishes are the tertiary consumers or top carnivores.

Organic matter → Bacteria → Molluscs
This is an example of a detritus food chain that starts with the decomposition of dead organic matter by bacteria.
Bacteria convert the complex organic molecules into simpler inorganic molecules which are then passed to aquatic organisms like molluscs.

Final answer
(C) Organic matter → Bacteria → Molluscs