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Question #46028
The Question
In a highly diverse forest ecosystem, a selective chemical agent eradicates a specific group of soil microarthropods and fungi. Over time, despite the continuous presence of a vast number of plant and herbivore species, the ecosystem's primary productivity crashes and severe nutrient immobility sets in. According to Paul Ehrlich’s Rivet Popper Hypothesis and principles of ecosystem functioning, how should this eradicated group be classified, and what is the primary cause of the ecosystem's collapse?
Options
- A.
They are 'seat rivets'; the collapse is due to the disruption of the grazing food chain (GFC) which indirectly halts the detritus food chain (DFC).
- B.
They are 'wing rivets'; the collapse is due to the loss of functional diversity, resulting in a biogeochemical bottleneck and failure of nutrient turnover.
- C.
They are 'seat rivets'; the collapse is due to a decrease in overall species richness, which directly reduces the ecosystem's resilience to alien species invasions.
- D.
They are 'wing rivets'; the collapse is due to a sudden increase in the standing crop of producers, which rapidly depletes the standing state of the ecosystem.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Diversity-Stability Relationship|Rivet Popper Hypothesis|Nutrient Immobility
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the Rivet Popper Hypothesis merely as 'loss of species = ecosystem decline' without connecting it to specific functional groups (like decomposers) and biogeochemical cycling.
The trap lies in assuming that high species richness (producers/consumers) alone guarantees stability.
This question forces the synthesis of Chapter 15 (Biodiversity - Rivet Popper) with Chapter 14 (Ecosystem - Decomposition and Nutrient Cycling), proving that ecosystem stability is fundamentally contingent on chemical cycling rather than just taxonomic richness.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Nutrient Immobility |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |