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Question #46021
The Question
According to ecological principles, both hydrarch and xerarch successions ultimately converge into a mesic climax community. However, in a specific region with optimal climatic conditions for a forest climax, succession permanently halts at a stunted shrubland stage. Soil analysis reveals an extreme acidic pH of 4.8. Which of the following best explains this arrested succession (edaphic climax)?
Options
- A.
The acidic pH causes rapid leaching of phosphorus into the lower soil horizons, making it unavailable to deep-rooted climax trees.
- B.
Phosphorus becomes biologically unavailable due to fixation by iron and aluminum oxides, halting the facilitation process required to support climax biomass.
- C.
The extreme pH shifts the phosphorus cycle from a sedimentary to a gaseous phase, rapidly depleting the ecosystem's nutrient reservoir.
- D.
Pioneer species in highly acidic soils exclusively follow the inhibition model, actively secreting allelochemicals that prevent mesic forest convergence.
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
Pioneer_Species|Climax_Community|Nutrient_Cycling|Sedimentary_Cycles
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume climate is the sole determinant of a climax community (climatic climax) and overlook 'edaphic climaxes' caused by soil properties.
Furthermore, a common misconception is confusing nutrient 'leaching' (washing away) with nutrient 'fixation/immobility' (chemical locking), which is the actual fate of phosphorus in extreme pH soils.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Ecosystem - Class 12 |
| Concept | Ecological Succession Climax |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |