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Question #45484
The Question
A plant population exposed to prolonged industrial pollution (acidic particulate matter and elevated UV-B) exhibits a heritable evolutionary shift: the average thickness of its pollen exine significantly increases over several generations. Correlating this adaptation with pollen biology and evolutionary principles, which of the following statements is INCORRECT?
Options
- A.
This phenomenon represents directional selection, where chemical stress acts as a selection pressure analogous to industrial melanism in Biston betularia.
- B.
The enhanced exine provides a superior shield, as its primary component, sporopollenin, can withstand high temperatures, strong acids, and alkalis.
- C.
The selection pressure favors genotypes with a highly active tapetum, which synthesizes and secretes greater amounts of sporopollenin precursors.
- D.
To compensate for the environmental stress, the microspores upregulate the secretion of sporopollenin from their pecto-cellulosic intine layer.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
Pollen Wall Chemistry|Industrial Melanism|Evolution
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the origin of the pollen wall layers.
While the intine is secreted by the microspore itself (gametophytic origin), the exine's sporopollenin is primarily derived from the tapetum (sporophytic origin).
The trap relies on mixing the location (intine) with the chemical (sporopollenin).
Furthermore, linking this micro-anatomical fact to macro-evolutionary concepts (directional selection/industrial melanism) tests true NCERT-Plus synthesis.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Pollen Wall Chemistry |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |