Ecosystems — BIOLOGY STD 12 Science — Question

Ecomposition It is the process of breaking down of complex organic matter into inorganic substances like water, carbon dioxide and nutrients by decomposers. Detritus is the raw material for decomposition. It includes dead remains of plants (leaves, bark and flowers) and animals including faecal matter.Different steps involved in the process of decomposition are:

1. Fragmentation: It is process of breakdown of detritus into smaller particles by detritivores (e.g. earthworm).
2. Leaching: It is the process by which water-soluble inorganic nutrients go down into the soil horizon and get precipitated as unavailable salts.
3. Catabolism: It is the process of degradation of detritus into simple organic material by the action of bacterial and fungal enzymes and then their further conversion into simpler inorganic compounds.

3. Humification: It is a process that leads to accumulation of a dark coloured amorphous and colloidal substance called humus, which is highly resistant to microbial action and undergoes decomposition at a very slow rate. Being colloidal in nature, it serves as a reservoir of nutrients.
4. Mineralisation: It is process of degradation of humus by microbial action and release of inorganic nutrients