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Question #46477
The Question
Ecologists are monitoring two distinct habitats: Habitat X (a terrestrial forest near a newly established coal-fired power plant) and Habitat Y (a freshwater lake receiving untreated domestic sewage). Over time, they observe the phenomenon of industrial melanism in Habitat X and a massive fish kill in Habitat Y. Which of the following statements correctly synthesizes the principles of biological monitoring and selective pressure in these habitats?
Options
- A.
The disappearance of lichens in Habitat X indicates high SO2 levels, driving directional selection, analogous to how a sharp rise in BOD in Habitat Y indicates high organic loading, leading to the elimination of sensitive aquatic species.
- B.
In Habitat X, the survival of melanic moths is a result of stabilizing selection due to soot deposition, whereas in Habitat Y, an increase in dissolved oxygen (DO) due to high BOD causes the fish kill.
- C.
Lichens in Habitat X and methanogenic bacteria in Habitat Y both serve as primary bio-indicators of heavy metal toxicity, triggering disruptive selection in their respective food webs.
- D.
The environmental stress in Habitat X directly alters the genotype of the moths to produce melanin, just as the high BOD in Habitat Y induces mutations in fish to tolerate low oxygen levels.
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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
Lichens|BOD|Industrial Melanism
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: The question parallels terrestrial and aquatic bio-indicators representing anthropogenic stress, coupled with the mechanism of natural selection.
The primary traps are the inverse relationship between BOD and DO (students often confuse high BOD with high DO) and the Lamarckian misconception that environmental stress 'induces' specific mutations rather than 'selecting' pre-existing ones.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Evolution - Class 12 |
| Concept | Industrial Melanism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |