Which of the following statements is wrong ?

Options

A. A stable community should show much variation in productivity from year to year
B. According to Tilman's long term ecosystem experiments increased diversity contributed to higher productivity.
C. Stable community must be resistant to occasional disturbances
D. Rich biodiversity is essential for ecosystem health but imperative for the very survival of the human race on this planet

Answer

To determine which statement is wrong, we need to analyze each statement provided regarding stable communities and biodiversity.

### Step-by-Step Solution:

1. **Understand the Concept of Stability in Biotic Communities**:
- A stable community is characterized by consistent productivity over the years, meaning there should be minimal variation in biomass production from year to year.
- Stability also includes resistance to environmental disturbances and resilience, which is the ability to recover from adverse effects.

2. **Evaluate the Statements**:
- **Statement A**: "A stable community shows a lot of variation in year-to-year productivity."
- This statement contradicts the definition of stability. A stable community should have little variation in productivity, making this statement incorrect.

- **Statement B**: "According to Tillman's long-term ecosystem experiments, the higher the diversity, the higher the productivity."
- This statement is correct as it reflects the findings of David Tilman’s experiments, which show a positive correlation between biodiversity and productivity.

- **Statement C**: "Stable community shows resistance against occasional disturbances and environmental stresses."
- This statement is also correct, as stable communities are known to withstand disturbances without significant changes.

- **Statement D**: "To maintain the health of ecosystems, we need rich biodiversity, and for the survival of the human race, biodiversity is imperative."
- This statement is correct as biodiversity is crucial for ecosystem services that support human life.

3. **Identify the Incorrect Statement**:
- After evaluating all the statements, it is clear that **Statement A** is the only incorrect statement. A stable community should not show a lot of variation in productivity.

### Conclusion:
The wrong statement is **Statement A**: "A stable community shows a lot of variation in year-to-year productivity."

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