Question

Below is shown a pond that represents a self-sustaining natural ecosystem with both biotic and abiotic components interacting in a balanced food web.

Based on the diagram, answer the questions :

Differentiate between the roles of producers and decomposers in such an ecosystem.

Hint:

Producers make food from sunlight. Decomposers break dead matter into simple nutrients and return them to the pond.

Answer 1

Step 1: Identify the two groups in the pond:
Producers are green organisms such as phytoplankton, algae and rooted water plants. They make their own food.
Decomposers are bacteria and fungi, shown at the lower left of the diagram. They feed on dead remains.

Step 2: Role of producers:
They trap solar energy by photosynthesis and change it into chemical energy stored in food.
They take in \( \mathrm{CO_2} \) and release oxygen into the water.
They form the first trophic level, so all consumers depend on them for food and energy.

Step 3: Role of decomposers:
They release enzymes on dead plants, dead animals and wastes, and break these down into simple inorganic substances.
This returns nutrients and \( \mathrm{CO_2} \) to the water and the bottom mud, so that producers can use them again.
They keep the nutrient cycle running and stop dead matter from piling up.

Step 4: Compare:
Producers bring energy into the pond, whereas decomposers recycle the materials locked in dead matter.

Final Answer:
Producers capture solar energy and make food for all other organisms. Decomposers break down dead organic matter and return nutrients to the pond for reuse.