Explain the structure and functions of a pond ecosystem.

1. 1 · Define in one line. An ecosystem is a functional unit of nature where organisms interact with each other and with their physical environment.
2. 2 · Describe the abiotic components. Water with dissolved inorganic and organic substances, the soil deposit at the bottom, sunlight, temperature and day-length.
3. 3 · Describe the biotic components.
   • Producers: phytoplankton, algae, floating, submerged and marginal plants.
   • Consumers: zooplankton, free-swimming and bottom-dwelling animals.
   • Decomposers: fungi, bacteria and flagellates at the bottom.
4. 4 · Explain the functions.
   • Autotrophs convert inorganic into organic matter using sunlight.
   • Heterotrophs consume the autotrophs.
   • Decomposers mineralise dead matter for reuse.
   • Energy moves one way to higher trophic levels and is lost as heat.
5. 5 · Draw a flow chart. [Flow chart: Sun → producers → consumers → dead matter → decomposers → nutrients back to producers]
6. 6 · Link to real life. A village tank works the same way: lotus and algae, fish and frogs, and bacteria in the mud.
7. 7 · Close in one line. So even a small pond performs all the functions of the biosphere.

Scoring tip: Write the pond's components under four headings: abiotic, producers, consumers and decomposers. Then add the one-way energy line.