Decomposers
Explanation
Decomposition is the process by which complex organic matter is broken down into simpler inorganic substances like carbon dioxide, water, and nutrients. This process is primarily carried out by organisms known as decomposers. The process involves steps such as fragmentation, leaching, catabolism, humification, and mineralization. Humification specifically leads to the accumulation of a dark-coloured, amorphous substance called humus, which is highly resistant to microbial action and serves as a reservoir of nutrients.
Option Analysis
- Primary consumers is incorrect: Primary consumers are herbivores that feed directly on living producers (plants). They do not feed on dead organic matter to convert it into humus.
- Secondary consumers is incorrect: Secondary consumers are carnivores that feed on primary consumers. They occupy the third trophic level and are not involved in the decomposition of dead matter.
- Decomposers is correct: Decomposers (primarily bacteria and fungi) are heterotrophic organisms that meet their energy and nutrient requirements by degrading dead organic matter or detritus. They secrete digestive enzymes that break down complex organic substances into simpler ones. This activity results in the formation of humus (humification) and the release of inorganic nutrients (mineralization) back into the soil.
- Autotrophs is incorrect: Autotrophs are producers (e.g., green plants, algae) capable of synthesizing their own food using sunlight or chemical energy. They generate organic matter rather than breaking it down.
Key Takeaway
Decomposers (bacteria and fungi) are the primary agents of humification and mineralization in an ecosystem. They recycle nutrients by converting dead organic matter (detritus) into humus and inorganic substances, maintaining the stability of the ecosystem.