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Question #46670
The Question
In a forest ecosystem, the gradual extinction of several herbivorous insect species does not significantly affect overall stability. However, the subsequent extinction of a specific keystone soil bacterium leads to a sudden, exponential decline in primary productivity due to a complete halt in the phosphorus cycle. Correlating this event with Paul Ehrlich’s Rivet Popper hypothesis and nutrient cycling principles, which of the following statements is INCORRECT?
Options
- A.
The initial stability of the ecosystem despite the loss of insect species illustrates functional redundancy, analogous to losing 'rivets on the seats' inside the airplane.
- B.
The soil bacterium acts as a 'rivet on the airplane wing', and its extinction causes severe nutrient immobilization, rendering essential elements inaccessible to primary producers.
- C.
The loss of this keystone recycler prevents the mobilization of phosphorus from its gaseous reservoir, abruptly halting the ecosystem's energy flow and biomass production.
- D.
Prior to the bacterium's extinction, the ecosystem maintained its functional integrity because the reservoir pool successfully met the deficit caused by any imbalance in the rate of influx and efflux.
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
Standing_Crop|Phytoplankton|Zooplankton|Trophic_Efficiency_Limits
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: The trap relies on 'Cognitive Overload'.
Students often focus so heavily on decoding the complex ecological analogy (Rivet Popper, functional redundancy, nutrient immobilization) that they gloss over a fundamental, foundational NCERT fact embedded in the option: the physical state of the nutrient reservoir.
Failing to strictly categorize nutrient cycles into Gaseous (Nitrogen, Carbon) and Sedimentary (Phosphorus, Sulphur) leads to selecting the wrong answer in multi-chapter synthesis questions.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Trophic Efficiency Limits |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |