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Question #47500
The Question
During the pioneer stage of primary succession on a bare rock (lithosere), an ecologist observes that while lichens actively drive pedogenesis, their standing crop remains extremely low. What is the primary ecological consequence of this negligible standing crop when the lichen colony undergoes senescence?
Options
- A.
It initiates a rudimentary detritus food chain but provides insufficient humus to sustain a complex grazing food chain, necessitating a transition to bryophytes.
- B.
It generates a high net primary productivity that directly establishes a complex grazing food chain before pedogenesis is complete.
- C.
It is quantified as the total inorganic nutrients dissolved from the rock, which immediately supports the invasion of higher vascular plants.
- D.
It shifts the ecosystem energy flow entirely to a grazing food chain, as the accumulated biomass provides sufficient soil depth for climax species.
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
Fungal Wall Chemistry|Lichen Symbiotic Logic|N-acetylglucosamine
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the 'ecological importance' of pioneer species (weathering rock) with their 'biomass contribution' (standing crop).
While lichens are critical for pedogenesis via acid secretion, their actual standing crop is negligible.
Failing to recognize that early lithosere energy flow is restricted to a rudimentary detritus food chain—due to insufficient biomass for a grazing food chain—leads to incorrect assumptions about succession rates and trophic complexity.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biological Classification - Class 11 |
| Concept | Lichen Symbiotic Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |