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Question #46054
The Question
According to David Tilman’s long-term ecosystem experiments, increased species diversity contributes to higher productivity and greater ecosystem stability (less year-to-year variation in total biomass). However, when an aggressive alien species like Eichhornia crassipes (Water Hyacinth) invades a native aquatic ecosystem, which of the following ecological outcomes best describes the disruption of this Diversity-Stability relationship?
Options
- A.
The ecosystem achieves higher stability because the invasive species significantly increases the net primary productivity and total biomass of the water body.
- B.
The ecosystem becomes less stable because the invasive species reduces native species richness, leading to a loss of functional redundancy despite a potential temporary increase in total biomass.
- C.
The ecosystem stability remains unaffected as the invasive species merely replaces the native primary producers, maintaining the original level of species richness.
- D.
The ecosystem experiences a simultaneous decrease in both total biomass and year-to-year variation, directly violating Gause's Competitive Exclusion Principle.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Ecosystem Services|Species Richness|Paul Ehrlich
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often conflate 'High Productivity/Biomass' with 'High Ecosystem Stability'.
The trap relies on the misconception that if an invasive species increases the total photosynthetic output or biomass of a lake, the ecosystem is thriving.
However, Tilman's hypothesis specifically dictates that stability is a function of 'species richness' and 'functional redundancy'.
A high-biomass monoculture created by an invasive species is inherently unstable.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biodiversity and Conservation - Class 12 |
| Concept | Diversity-Stability Relationship |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |