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Question #47543
The Question
In certain homosporous pteridophytes (e.g., Lycopodium), the prothallus is subterranean and achlorophyllous. If a specific soil fungal population is eradicated from their habitat, the pteridophyte population eventually collapses despite optimal soil moisture, temperature, and shade. Which of the following best explains this phenomenon?
Options
- A.
The sporophyte fails to undergo meiosis due to the absence of fungal-derived growth regulators.
- B.
Co-extinction occurs because the gametophyte is obligately mycoheterotrophic and fails to establish without the fungi.
- C.
The absence of fungi prevents the retention of capillary water required for the chemotactic movement of antherozoids.
- D.
Amensalism between the pteridophyte and the remaining soil microbes prevents the germination of haploid spores.
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
Cleistogamy|Chasmogamy|Prothallus|Gametophyte
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' bridges the Plant Kingdom (prothallus independence and nutritional requirements) with Biodiversity and Conservation (Co-extinction).
Students typically associate co-extinction strictly with plant-pollinator mutualisms (like the Pronuba moth and Yucca) and often falsely assume all pteridophyte prothalli are green and photosynthetic, missing the obligate fungal dependency of subterranean gametophytes.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Kingdom - Class 11 |
| Concept | Pteridophyte Prothallus Nature |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |