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Question #46914
The Question
The inclusion of the genus Selaginella within the traditional Pteridophyte hierarchy presents an evolutionary paradox: its vegetative morphology aligns with primitive vascular plants, yet its reproductive strategy foreshadows higher taxa. Which specific feature of Selaginella establishes this evolutionary bridge (precursor to the seed habit) and fundamentally differentiates its life cycle from homosporous genera like Pteris?
Options
- A.
The development of a free-living, monoecious macroscopic prothallus from morphologically distinct spores.
- B.
The permanent retention of the megaspore within an integumented megasporangium, forming a true seed.
- C.
The retention of the female gametophyte on the parent sporophyte for variable periods, where zygote development occurs.
- D.
The complete loss of the sporophytic generation's dependence on water for fertilization due to the evolution of heterospory.
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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
Taxonomic Hierarchical Rank|Pteridophyte Heterospory Evolution|Selaginella
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse 'precursor to the seed habit' with the actual possession of seed-like structures (integuments/ovules) or assume that heterospory automatically eliminates the need for water in fertilization.
Option B acts as an 'Over-extrapolation Trap' by introducing integuments, while Option D is a 'Functional Confusion Trap' that conflates heterospory with the siphonogamy (pollen tube formation) of higher seed plants.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | The Living World - Class 11 |
| Concept | Taxonomic Hierarchical Rank |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |