Question

Choose the correct sequence of steps involved in decomposition

• A. Fragmentation $\rightarrow$ Mineralisation $\rightarrow$ Humification $\rightarrow$ Leaching $\rightarrow$ Catabolism
• B. Fragmentation $\rightarrow$ Leaching $\rightarrow$ Catabolism $\rightarrow$ Humification $\rightarrow$ Mineralisation
• C. Fragmentation $\rightarrow$ Catabolism $\rightarrow$ Leaching $\rightarrow$ Humification $\rightarrow$ Mineralisation
• D. Fragmentation $\rightarrow$ Leaching $\rightarrow$ Catabolism $\rightarrow$ Mineralisation $\rightarrow$ Humification

Hint:

Decomposition follows Fragmentation $\rightarrow$ Leaching $\rightarrow$ Catabolism $\rightarrow$ Humification $\rightarrow$ Mineralisation for nutrient cycling.

Answer 1

The Correct Option is B

• Definition of Decomposition: Decomposition is the process by which organic matter is broken down into simpler substances, involving several sequential steps.
• Step-by-Step Analysis:
  • Fragmentation: Physical breakdown of detritus into smaller pieces by detritivores.
  • Leaching: Water-soluble nutrients are washed away from the detritus.
  • Catabolism: Decomposers (e.g., bacteria, fungi) break down complex compounds into simpler ones through enzymatic action.
  • Humification: Formation of humus, a dark, stable organic material, from partially decomposed matter.
• Option Analysis:
  • (1) Fragmentation → Mineralisation → Humification → Leaching → Catabolism: Incorrect sequence; mineralisation occurs last.
  • (2) Fragmentation → Leaching → Catabolism → Humification → Mineralisation: Follows the natural progression of decomposition. This is correct.
  • (3) Fragmentation → Catabolism → Leaching → Humification → Mineralisation: Catabolism precedes leaching, which is unnatural.
  • (4) Fragmentation → Leaching → Catabolism → Mineralisation → Humification: Humification occurs before mineralisation, which is incorrect.
• Conclusion: The correct answer is (2) Fragmentation → Leaching → Catabolism → Humification → Mineralisation, as it reflects the ecological sequence.