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Question #46682
The Question
An environmental economist uses Robert Costanza's model to predict a steady, linear decline in the US $33 trillion annual value of ecosystem services as species richness decreases. Based on Paul Ehrlich’s 'Rivet Popper Hypothesis' described in NCERT, why is this linear prediction biologically flawed?
Options
- A.
Because the loss of 'rivets' on the airplane wings (keystone species) causes a sudden, non-linear ecosystem collapse, whereas the loss of 'seat rivets' (redundant species) initially maintains stability.
- B.
Because Costanza's model attributes 50% of the value to soil formation, which is entirely independent of species richness and functional redundancy.
- C.
Because ecosystem services are driven solely by endemic species, meaning the economic value drops to zero only when the last endemic species goes extinct.
- D.
Because the Rivet Popper Hypothesis states that every species is equally critical to flight safety, resulting in an exponential, rather than linear, decline from the very first extinction.
Check Your Answer
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
Energy_Flow|Biomass|Trophic_Level_Efficiency|Primary_Succession
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize Costanza's $33 trillion figure and Ehrlich's airplane analogy separately without synthesizing them.
The pivot is understanding that Ehrlich's model describes 'functional redundancy' and 'threshold-based collapse' (non-linear), which directly challenges linear economic depreciation models.
The primary trap is Option D, which assumes all species are equally important, missing the crucial 'wing vs. seat' distinction that defines the hypothesis.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Primary Succession Facilitation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |