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Question #46665
The Question
An ecologist observes a forest ecosystem that maintains a very high Net Primary Productivity (NPP). However, following the localized extinction of a single top-predator species, the ecosystem experiences a rapid cascade of co-extinctions and structural collapse, even though the initial NPP remained high. Based on Paul Ehrlich’s Rivet Popper hypothesis and principles of ecosystem stability, which of the following statements best explains this phenomenon?
Options
- A.
The lost predator was a 'rivet on the airplane seat', indicating that the ecosystem lacked functional redundancy at the producer level.
- B.
The predator acted as a 'rivet on the airplane wing', demonstrating that structural stability and resistance to co-extinction can be decoupled from the ecosystem's initial primary productivity.
- C.
The loss of the predator reduced species richness, which according to David Tilman's experiments, always results in an immediate and proportional drop in Net Primary Productivity.
- D.
The predator represented a 'rivet on the airplane wing', whose removal directly decreased the Gross Primary Productivity (GPP) by halting the 10% energy flow.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Decomposition Rate Modifiers|Nutrient Cycling Reservoirs
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between Ecosystem Productivity (energy capture) and Ecosystem Stability (resilience to species loss).
A common misconception is that high NPP automatically equals high stability.
The Rivet Popper hypothesis highlights that losing a keystone species (wing rivet) causes structural collapse via trophic cascades, regardless of the baseline productivity, effectively decoupling the two concepts in this specific scenario.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Decomposition Rate Modifiers |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |