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Question #46486
The Question
In a small, geographically isolated population of early hominids, alleles associated with a higher cranial capacity rapidly reached fixation following a severe environmental bottleneck. According to the principles of population genetics and the Neutral Theory of evolution, which of the following statements is INCORRECT regarding this evolutionary shift?
Options
- A.
The fixation of the high cranial capacity alleles occurred due to random sampling errors rather than their specific adaptive advantage.
- B.
The new hominid population will demonstrate a perturbed Hardy-Weinberg equilibrium with significantly reduced overall genetic variability.
- C.
The rapid phenotypic shift represents a classic example of directional natural selection driven by the survival need for advanced cognitive abilities.
- D.
If this isolated paleo-deme expands and eventually diverges into a new species, the original bottleneck survivors would be considered the founders.
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
Hominid Cranial Capacity|Allele Frequency Drift
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students strongly associate 'increased cranial capacity in human evolution' exclusively with 'Directional Natural Selection' (adaptation for intelligence/tool use).
The trap exploits this adaptationist bias.
Students often fail to recognize that in small populations (bottlenecks), Genetic Drift is the dominant evolutionary force and can fix alleles by pure chance, regardless of their adaptive value.
Option C sounds like a standard NCERT fact about human evolution, making it a highly attractive 'True' statement, but it is fundamentally false in the specific context of a population bottleneck.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Evolution - Class 12 |
| Concept | Hominid Cranial Capacity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |