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 :

Draw a simple food chain operating in such an ecosystem and label each trophic level.

Hint:

Start with a producer, add a primary consumer, then a secondary and a tertiary consumer, and label the trophic levels 1 to 4.

Answer 1

Step 1: Recall what a food chain is:
A food chain shows who eats whom in a straight line. Each step in the chain is a trophic level.

Step 2: Build the chain from pond organisms:
The first level is the producer: phytoplankton (algae).
The second level is the primary consumer: zooplankton or a small snail that eats the algae (diagram label: primary consumers).
The third level is the secondary consumer: a small fish that eats the zooplankton.
The fourth level is the tertiary consumer: a large fish.

Step 3: Write it with labels:
Phytoplankton \( \rightarrow \) Zooplankton \( \rightarrow \) Small fish \( \rightarrow \) Large fish.
Trophic levels: producer (first), primary consumer (second), secondary consumer (third), tertiary consumer (fourth).
A labelled sketch of this chain with arrows is expected in the answer script.

Final Answer:
Phytoplankton (producer, I) to zooplankton (primary consumer, II) to small fish (secondary consumer, III) to large fish (tertiary consumer, IV).