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Question #46018
The Question
The drivers of the 'Evil Quartet' cause a severe collapse of the detritivore and decomposer populations in a mature terrestrial ecosystem. All of the following will be systemic consequences of this collapse on the ecosystem's productivity and energy flow, EXCEPT:
Options
- A.
A drastic reduction in the primary pathway for energy flow within the terrestrial ecosystem.
- B.
A cascading decline in the secondary productivity of the Grazing Food Chain (GFC) due to impaired nutrient mineralization.
- C.
An accumulation of detritus that locks up essential inorganic nutrients, limiting the stoichiometric supply for autotrophs.
- D.
A compensatory increase in the trophic efficiency of the GFC, as it becomes the sole independent pathway for energy transfer.
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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
Detritus Food Chain Dominance | Secondary Productivity | Trophic Efficiency Limits | Evil Quartet Drivers
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often mistakenly believe that the Grazing Food Chain (GFC) and Detritus Food Chain (DFC) operate in complete isolation, and that secondary productivity is solely a function of herbivore-carnivore dynamics.
This question tests the NCERT-Plus synthesis that terrestrial GFC stability and secondary productivity are fundamentally constrained by the nutrient 're-loading' (mineralization) driven by the DFC.
Option D exploits the 'Functional Independence' misconception by falsely suggesting the GFC can independently compensate for a DFC collapse.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Detritus Food Chain Dominance |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |