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Question #46680
The Question
In a climax mesic forest, the localized extinction of a specific pollinator insect leads to the subsequent extinction of its host plant. Following this event, ecologists observe a drastic increase in the year-to-year variation of the total community biomass. Based on NCERT principles of biodiversity and succession, which of the following statements correctly synthesizes the ecological concepts at play?
Options
- A.
The event demonstrates co-extinction of obligate mutualists, acting as the loss of a 'wing rivet' that compromises the ecosystem stability defined by Tilman.
- B.
The pollinator acts as a 'seat rivet' in Ehrlich's analogy, and its loss initiates a retrogressive succession that ultimately increases the community's overall productivity.
- C.
The increased variation in biomass indicates that the ecosystem is highly resilient, successfully buffering the cascading loss caused by the co-extinction.
- D.
The co-extinction disrupts the climax community, accelerating its convergence toward a more diverse and stable pioneer seral stage.
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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
Pioneer_Species|Lichen|Invasive_Species|Ecological_Succession_Climax
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question requires the synthesis of three distinct NCERT concepts usually memorized in isolation: Co-extinction (Biodiversity loss), Ehrlich's Rivet Popper Hypothesis (Keystone vs. redundant species), and Tilman's definition of ecosystem stability (biomass variation).
The trap lies in misinterpreting Tilman's metric—students often forget that 'increased variation' means 'decreased stability', or they confuse the 'wing rivet' (critical) with the 'seat rivet' (minor) in Ehrlich's analogy.
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 |