Which of the following food chain shows spindle shape pyramid

Options

A. Grass `to` Insects `to` Frog
B. Phytoplankton `to` Zooplankton `to` Small fish
C. Tree `to` Brids `to` Hawks
D. Tree `to` Birds `to` Insects `to` Bacteria

Answer

To determine which food chain shows a spindle shape pyramid, we need to analyze the options based on the concept of the pyramid of numbers. A spindle-shaped pyramid typically occurs when there are fewer individuals at the top of the food chain compared to the middle and base levels.

### Step-by-Step Solution:

1. **Understanding the Food Chains**:
- The first step is to examine each food chain option provided:
- Option 1: Grass → Insect → Frog
- Option 2: Phytoplankton → Zooplankton → Small Fish
- Option 3: Tree → Bird → Hawk
- Option 4: Tree → Bird → Insect → Bacteria

2. **Analyzing Each Food Chain**:
- **Option 1 (Grass → Insect → Frog)**:
- Grass (producers) have a large number, insects (primary consumers) have a moderate number, and frogs (secondary consumers) have fewer. This could resemble a pyramid but not a spindle shape.
- **Option 2 (Phytoplankton → Zooplankton → Small Fish)**:
- Similar to option 1, phytoplankton are abundant, zooplankton are less, and small fish are even fewer. This also does not create a spindle shape.
- **Option 3 (Tree → Bird → Hawk)**:
- Trees are numerous, birds are fewer, and hawks (top predators) are the least numerous. This creates a spindle shape as the numbers decrease significantly from base to top.
- **Option 4 (Tree → Bird → Insect → Bacteria)**:
- This chain is complex, but it does not create a clear spindle shape as the number of bacteria can be very high, disrupting the shape.

3. **Identifying the Correct Option**:
- After analyzing all options, **Option 3 (Tree → Bird → Hawk)** clearly shows a spindle shape pyramid due to the decreasing number of organisms from base to apex.

4. **Conclusion**:
- The food chain that shows a spindle shape pyramid is **Tree → Bird → Hawk**.