Which organisms recycle nutrients by breaking down dead organic matter?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Decomposers
Nutrients in an ecosystem are used again and again. Plants take them from the soil, animals get them by eating, and dead bodies and wastes lock them up in complex organic matter. Decomposition breaks this dead matter down and returns the nutrients to the soil for plants to use again.
Option (1) Producers — Incorrect. Producers (green plants) make food from simple inorganic materials by photosynthesis. They take up the released nutrients but do not break down dead matter.
Option (2) Decomposers — Correct. Decomposers, mainly fungi and bacteria, break down complex organic matter into inorganic substances such as carbon dioxide, water and nutrients. This mineralisation releases nutrients back for reuse by plants.
Option (3) Primary consumers — Incorrect. Primary consumers are herbivores. They feed on living plants, not on dead organic matter.
Option (4) Secondary consumers — Incorrect. Secondary consumers are carnivores that eat herbivores. They pass energy up the food chain but do not decompose dead matter.
NCERT Extract:
Ecosystem – Structure and Function – “… The decomposers are the fungi, bacteria and flagellates especially abundant in the bottom of the pond. This system performs all the functions of any ecosystem and of the biosphere as a whole, i.e., conversion of inorganic into organic material with the help of the radiant energy of the sun by the autotrophs; consumption of the autotrophs by heterotrophs; decomposition and mineralisation of the dead matter to release them back for reuse by the autotrophs, these event are repeated over and over again.”
Decomposition – “You may have heard of the earthworm being referred to as the farmer’s ‘friend’. This is so because they help in the breakdown of complex organic matter as well as in loosening of the soil. Similarly, decomposers break down complex organic matter into inorganic substances like carbon dioxide, water and nutrients and the process is called decomposition.”