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Question #46048
The Question
In a large tropical continent, the species-area relationship for native angiosperms initially exhibits a Z-value of 1.1. Following the widespread invasion of an aggressive exotic weed (Parthenium hysterophorus), extensive competitive exclusion of native flora occurs. Based on the Species-Area relationship equation and Paul Ehrlich’s Rivet Popper hypothesis, which of the following statements correctly describes the subsequent impact on the ecosystem?
Options
- A.
The Z-value for native angiosperms will increase beyond 1.2, as the exotic weed introduces a new ecological niche, acting as a crucial 'rivet' that enhances ecosystem stability.
- B.
The Z-value for native angiosperms will decrease, reflecting a flattened slope due to reduced species richness, effectively 'popping rivets' and threatening ecosystem functioning.
- C.
The Y-intercept (C-value) will increase while the Z-value remains constant, because competitive exclusion only alters local species composition without affecting the regional species accumulation rate.
- D.
The Z-value will shift to the 0.1 - 0.2 range characteristic of small areas, because the exotic weed strictly acts as a 'rivet on the seats', leaving the ecosystem's overall flight safety uncompromised.
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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
Ecosystem Function|Functional Redundancy|Extinction Dynamics
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that Z-values for continents are 0.6 to 1.2, treating them as static constants.
The trap tests the understanding that the Z-value is a dynamic slope dependent on species richness (S).
An invasive species causing monodominance drastically reduces S, thereby flattening the slope (decreasing Z).
Furthermore, it synthesizes this mathematical concept with the theoretical Rivet Popper hypothesis to assess ecosystem stability.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biodiversity and Conservation - Class 12 |
| Concept | Z-value in Large Areas |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |