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Question #45314
The Question
An alien insect species invades a stable forest ecosystem, competitively displacing the exclusive native pollinator of an endemic, bisexual plant species. This plant normally relies on protandry to ensure xenogamy but lacks genetic self-incompatibility. In the prolonged absence of its specific pollinator, the plant population survives by relying on overlapping maturation phases in some flowers. Which of the following best describes the subsequent genetic and ecological fallout?
Options
- A.
The population shifts to autogamy, leading to inbreeding depression and a gradual population decline that destabilizes the ecosystem, analogous to the 'Rivet Popper' hypothesis.
- B.
The population shifts to geitonogamy, which genetically mimics xenogamy, thereby maintaining niche stability and preventing co-extinction.
- C.
The plant undergoes competitive release, rapidly evolving dioecy to ensure obligate cross-pollination and restore ecosystem equilibrium.
- D.
The plant transitions to cleistogamy to ensure assured seed set, which increases genetic vigor and prevents the 'Rivet Popper' effect.
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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
Alien Species Invasion Impacts|Outbreeding Device Logic|Niche Overlap vs. Resource Partitioning
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often assume that outbreeding devices (like protandry) make a plant completely immune to selfing.
However, if the device is purely temporal (dichogamy) and not genetic (self-incompatibility), pollinator absence can force late-stage selfing.
This question tests cross-chapter synthesis, linking reproductive failure and inbreeding depression (Chapter 2) to ecosystem-level theories like the Rivet Popper hypothesis and Alien Species Invasion (Chapter 15).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Outbreeding Device Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |