Ecosystem Ques 24
24. Decomposers are organisms that
[1994]
(a) elaborate chemical substances, causing death of tissues
(b) operate in living body and simplifying organic substances of cells step by step
(c) attack and kill plants as well as animals
(d) operate in relay terms, simplifying step by step the organic constituents of dead body
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Answer : d
Hints & Solutions
(d) Decomposers act on dead bodies converting complex organic constituents into simpler soluble form. They obtain their energy from dead organisms. Decomposers themselves are organisms (often fungi, earthworms, or bacteria) that break down organic materials to gain nutrients and energy. Decomposers accelerate the natural process of decomposition. They supply the required nutrients for other trophic levels. The fungi found on the tree are decomposers. When an organism dies, it leaves behind nutrients that are tightly bound together. A scavenger might eat the carcass, but its feces would still contain a considerable amount of unused energy and nutrients. Decomposers will later induce further breakdown. This last step releases raw nutrients (such as nitrogen, phosphorus and magnesium) in a form usable to plants, which quickly incorporates the chemicals into their own cells. This process greatly increases the nutrient-load of an ecosystem, in turn allowing for greater biodiversity.
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