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Question #46483
The Question
According to the evolutionary ecology of parasitism, parasites and their hosts often engage in a co-evolutionary 'arms race'. If a highly virulent obligate intestinal parasite and its mammalian host co-evolve over millions of years, resulting in the host developing complete tolerance and the parasite evolving avirulence to maximize its own transmission, how does the classical biotic interaction matrix change, and why?
Options
- A.
It shifts from (+/-) to (+/0); natural selection favors reduced virulence to ensure host survival and continuous parasite transmission.
- B.
It remains (+/-); the parasite still derives nutrition, which inherently constitutes a negative metabolic drain on the host's fitness.
- C.
It shifts from (+/-) to (-/-); the continuous co-evolutionary arms race depletes the evolutionary fitness of both interacting species.
- D.
It shifts from (+/-) to (+/+); the avirulent parasite automatically provides competitive exclusion against other pathogens, benefiting the host.
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
Co-evolutionary Resistance|Biotic Interactions - Positive/Negative sign matrix|Evolutionary Ecology of Parasitism
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often view biotic interaction signs (like +/- for parasitism) as static, permanent taxonomic traits rather than fluid, evolutionarily dynamic states.
The trap lies in assuming that an organism historically classified as a 'parasite' must always exert a negative (-) pressure on the host, ignoring the Red Queen dynamics where natural selection favors avirulence to maximize obligate parasite transmission.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Evolution - Class 12 |
| Concept | Co-evolutionary Resistance |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |