Before You Begin
Question #47521
The Question
Heterospory, considered a crucial precursor to the seed habit, is observed in certain pteridophytes but is entirely absent in bryophytes. Which of the following structural and physiological constraints fundamentally prevents the evolution of heterospory in bryophytes?
Options
- A.
The sporophyte is unbranched, non-vascular, and nutritionally dependent on the gametophyte, restricting the metabolic resource allocation required for megaspore provisioning.
- B.
The dominant, photosynthetic gametophyte generation actively suppresses the expression of heterosporous genes within the dependent sporophyte capsule.
- C.
Bryophytes strictly require external water for zooidogamous fertilization, a condition that is evolutionarily incompatible with the retention of a megaspore.
- D.
The sporophyte in advanced bryophytes lacks a foot and seta, preventing the adequate transfer of nutrients from the gametophyte to the developing sporangium.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Pteridophyte Heterospory Evolution|Aneuploidy vs Polyploidy|Sexual Reproduction Variations
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that 'heterospory begins in pteridophytes' without understanding the anatomical prerequisites.
The trap lies in Option C, as students heavily associate bryophytes with 'water for fertilization' and might falsely link this to the inability to form seeds/megaspores, forgetting that heterosporous pteridophytes share this exact water requirement.
The true limiting factor is the sporophyte's lack of independent vascular infrastructure and its parasitic nature.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Kingdom - Class 11 |
| Concept | Pteridophyte Heterospory Evolution |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |