In a terrestrial ecosystem,

Options

A. A similar proportion of energy flows through the grazing food chain as compared to the detritus food chain.
B. A smaller proportion of energy flows through the detritus food chain as compared to grazing food chain.
C. Equal proportion of energy flows through detritus food chain and grazing food chain
D. No energy flows through detritus food chain and grazing food chain.

Answer

To solve the question regarding energy flow in a terrestrial ecosystem, we need to analyze the differences between the Grazing Food Chain (GFC) and the Detritus Food Chain (DFC).

### Step-by-Step Solution:

1. **Understanding the Food Chains**:
- **Grazing Food Chain (GFC)**: This food chain starts with producers (like plants) that convert sunlight into energy through photosynthesis. The energy flows from producers to herbivores (primary consumers) and then to carnivores (secondary consumers).
- **Detritus Food Chain (DFC)**: This food chain begins with dead organic matter (detritus) and involves decomposers like bacteria and fungi that break down this organic material. The energy in this chain primarily comes from the decomposition of organic matter.

2. **Energy Source Comparison**:
- In the GFC, the primary source of energy is sunlight, which is abundant and allows for a significant energy flow through the ecosystem.
- In the DFC, the energy source is the organic matter from dead organisms, which is less compared to the energy available from sunlight.

3. **Proportion of Energy Flow**:
- Since the GFC utilizes sunlight as its energy source, it generally has a higher energy flow compared to the DFC, which relies on the decomposition of organic matter.
- Therefore, a smaller proportion of energy flows through the DFC compared to the GFC.

4. **Evaluating the Options**:
- **Option 1**: Similar proportion of energy flow through both chains - **Incorrect** (GFC has more energy).
- **Option 2**: Smaller proportion of energy flow through DFC compared to GFC - **Correct**.
- **Option 3**: Equal proportion of energy flow - **Incorrect** (GFC has more energy).
- **Option 4**: No energy flow through either chain - **Incorrect** (both chains have energy flow).

5. **Conclusion**:
- The correct answer is that a smaller proportion of energy flows through the Detritus Food Chain (DFC) compared to the Grazing Food Chain (GFC).

### Final Answer:
The correct option is: **A smaller proportion of energy flows through the detritus food chain as compared to the grazing food chain.**