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Question #45826
The Question
Plant height in a wild population is a quantitative trait controlled by three independent polygenes (A, B, and C) and environmental factors, initially displaying a normal bell-shaped distribution. A permanent environmental shift introduces a strict survival threshold, where only plants with the shortest phenotypes survive a new herbivore. Over successive generations, which of the following statements is INCORRECT regarding the evolutionary and genetic response of this population?
Options
- A.
The peak of the phenotypic distribution curve will shift towards the left, demonstrating directional selection.
- B.
The intrinsic additive contribution of each dominant allele to the phenotype will decrease to adapt to the new environment.
- C.
The overall phenotypic variance of the population will decrease due to the elimination of taller phenotypes.
- D.
The Hardy-Weinberg equilibrium will be disrupted as the frequency of recessive alleles significantly increases.
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
Polygenic Inheritance Curve|Allele Frequency Drift|Phenotypic Plasticity
Why This Question Is Tricky
Common Mistakes
The Conceptual Pivot lies in distinguishing between 'Population Genetics' (allele frequencies changing due to selection) and 'Molecular Genetics' (the mechanism of gene expression).
Students often fall for the Lamarckian trap, assuming that the environment changes the fundamental physiological rule (additive effect) of how an allele builds the phenotype, rather than simply selecting which alleles survive.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Polygenic Inheritance Curve |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |