In the aquatic ecosystem of a pond, which of the following components is represented by fungi, bacteria and flagellates?
- (a)Autotrophic components
- (b)Consumers
- (c)Decomposers
- (d)Abiotic components
Correct — B or C (both accepted). Fungi and bacteria are the classic decomposers (saprotrophs) of a pond: they break down dead organic matter and release nutrients back into the water. Flagellates, though, are typically heterotrophic protozoans that ingest bacteria and organic particles rather than decomposing dead matter enzymatically — which places them functionally among the consumers (micro-grazers) of the pond's food web. Because the named trio spans both roles (bacteria/fungi as decomposers, flagellates as consumers), the commission granted grace and accepted both (b) Consumers and (c) Decomposers.
- (a)Autotrophic components — Autotrophs (producers) are photosynthetic organisms such as phytoplankton, algae and aquatic plants that fix their own energy from sunlight — fungi, bacteria and flagellates as a group are not photosynthetic producers.
- (d)Abiotic components — Abiotic components are non-living factors — water, dissolved nutrients, temperature, light. Fungi, bacteria and flagellates are all living organisms, so this option is wrong.
A pond's living (biotic) community is conventionally split into three functional groups: autotrophic producers (phytoplankton, algae, submerged/floating plants) that fix energy; consumers (zooplankton, insects, fish, and heterotrophic protozoans) that feed on other organisms; and decomposers (chiefly saprotrophic bacteria and fungi) that break down dead organic matter and recycle nutrients.
This question tests whether a student can place named organisms (fungi, bacteria, flagellates) into their correct ecological role. The trap is assuming every microbe in a pond is automatically a 'decomposer' — decomposition specifically means enzymatic breakdown of dead matter (bacteria, fungi), while many flagellates are particulate feeders that graze on bacteria, functioning more like consumers.
- Decomposers (saprotrophs) in a pond: chiefly bacteria and fungi — break down dead organic matter
- Consumers: zooplankton, insects, fish, and heterotrophic protozoans (including many flagellates) that feed on other organisms
- Producers/autotrophs: phytoplankton, algae, aquatic plants — fix energy via photosynthesis
- MPPSC granted grace on this question, accepting both 'Consumers' and 'Decomposers' as correct
Fungi and bacteria are classic decomposers; flagellates lean toward consumers — which is why both (b) and (c) were accepted.
- Treating every microorganism in a pond as a 'decomposer' by default
- Missing that some flagellates (e.g., Euglena) are photosynthetic while others are heterotrophic consumers
MPPSC/UPSC test ecosystem-component classification by naming specific organisms and asking which functional group (producer/consumer/decomposer/abiotic) they belong to.
No directly related past PYQ was found (a matching prior question exists but isn't attemptable yet).
- practice — not a real PYQ
Which of the following is the correct example of decomposer organisms in an ecosystem?
- (a)Phytoplankton and algae
- (b)Zooplankton and fish
- (c)Bacteria and fungi
- (d)Insects and birds
Answer(c) Bacteria and fungi.
- practice — not a real PYQ
The progressive decline in energy as it passes from one trophic level to the next in an ecosystem is best described by:
- (a)Hardy-Weinberg principle
- (b)Ten percent law
- (c)Law of the minimum
- (d)Competitive exclusion principle
Answer(b) Ten percent law (Lindeman's trophic efficiency rule).