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Question #45984
The Question
Two sympatric angiosperm species, X and Y, share the same fundamental niche and rely on a single, limited pollinator species. Historically, they avoided Gause's competitive exclusion via temporal resource partitioning: Species X flowers in early spring, strictly triggered by a specific critical photoperiod, while Species Y flowers in late spring, triggered by seasonal temperature accumulation. If rapid global warming causes the required temperature accumulation for Species Y to occur much earlier in the year, while the astronomical photoperiod remains unchanged, which of the following is the most likely ecological consequence?
Options
- A.
Species X will undergo a rapid phenotypic shift in its phytochrome system to flower earlier, thereby maintaining temporal resource partitioning.
- B.
The decoupling of environmental cues will cause simultaneous flowering, leading to maximum niche overlap, intense interspecific competition, and a decline in Darwinian fitness for the inferior competitor.
- C.
Both species will transition exclusively to cleistogamous reproduction to bypass the pollinator shortage, ensuring their continued indefinite coexistence.
- D.
The temporal gap between their flowering times will widen, further reducing niche overlap and increasing the carrying capacity for both species.
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
Photoperiodism Thresholds|Niche Overlap vs. Resource Partitioning|Ecological Fitness
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often fail to distinguish between the immutability of astronomical cues (photoperiodism) and the plasticity of climate-dependent cues (temperature accumulation).
The trap lies in assuming both species will adapt equally or that the temporal gap will widen.
By understanding that photoperiod is fixed while temperature shifts, students can deduce that climate change forces a phenological collision, directly violating MacArthur's resource partitioning and invoking Gause's competitive exclusion.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Plant Growth and Development - Class 11 |
| Concept | Photoperiodism Thresholds |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |