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Question #46936
The Question
Early artificial systems of classification often grouped plants based on their economic importance or specific functional traits (e.g., secondary metabolites). Modern phylogenetic systematics rejects this approach, particularly for traits governed by pleiotropy. Which of the following statements best explains why pleiotropic traits are unreliable markers for determining true phylogenetic relationships?
Options
- A.
They undergo independent assortment during meiosis, leading to the continuous reshuffling of taxonomic characters in every generation.
- B.
A single genetic mutation can simultaneously alter multiple functional and morphological phenotypes, creating a false perception of large evolutionary divergence.
- C.
Pleiotropic genes are highly conserved across all domains of life, making it impossible to distinguish between closely related species or genera.
- D.
They are exclusively expressed as polygenic traits, meaning their phenotypic expression is entirely dependent on environmental selection pressures.
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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
Systematic Classification Scope|Pleiotropy Logic|Economic Importance Matrix
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize the definitions of 'Pleiotropy' (Genetics) and 'Artificial Classification' (Taxonomy) in isolation.
The trap lies in failing to synthesize them.
The core misconception is assuming that a large phenotypic difference always equals a large evolutionary (genetic) distance.
Pleiotropy proves this false, as one minor genetic change can drastically alter an organism's 'economic' or 'functional' classification, demonstrating why modern taxonomy relies on stable, derived molecular markers rather than highly variable pleiotropic traits.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | The Living World - Class 11 |
| Concept | Systematic Classification Scope |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |