Question

Assertion (A) : In terrestrial ecosystem much larger fraction of energy flows through grazing food chain.
Reason (R) : Grazing food chain may be connected to Detritus food chain at some levels.

• A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
• B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
• C. Assertion (A) is true, but Reason (R) is false.
• D. Assertion (A) is false, but Reason (R) is true.

Hint:

Aquatic Ecosystem $\rightarrow$ GFC is major.
Terrestrial Ecosystem $\rightarrow$ DFC is major.
This is a high-yield comparison for ecology exams.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Ecosystems have two main types of food chains: the Grazing Food Chain (GFC), which starts with producers, and the Detritus Food Chain (DFC), which starts with dead organic matter.
Step 2: Detailed Explanation:
Assertion (A): In a terrestrial ecosystem, a much larger fraction of energy actually flows through the Detritus Food Chain (DFC) rather than the Grazing Food Chain (GFC). In contrast, in aquatic ecosystems, GFC is the major conduit for energy flow. Thus, Assertion (A) is false.
Reason (R): In nature, food chains are rarely isolated. The GFC and DFC are interconnected. For example, an animal from the GFC (like a bird) might eat an earthworm from the DFC. These interconnections form a food web. Thus, Reason (R) is true.
Step 3: Final Answer:
Since the assertion is false and the reason is true, the correct code is (D).