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Question #46871
The Question
A soil pollutant selectively paralyzes the enteronephric nephridia (septal and pharyngeal) of Pheretima in a terrestrial ecosystem, while exonephric nephridia remain functional. How will this specifically impact the earthworm's physiology and the local ecosystem's nutrient cycling?
Options
- A.
The earthworm will face severe dehydration due to the loss of intestinal water reabsorption, and the ecosystem's standing crop will decrease due to reduced nitrogen mineralization in worm casts.
- B.
The earthworm will shift to strict ammonotelism to conserve energy, causing a rapid spike in soil toxicity and a subsequent decline in the detritus food chain.
- C.
Excretion of nitrogenous waste onto the body surface will halt, reducing the direct diffusion of ammonia into the soil and slowing down the nitrogen cycle.
- D.
The earthworm's ability to mechanically breakdown detritus in the gizzard will cease, directly depleting the sedimentary phosphorus reservoir of the ecosystem.
Check Your Answer
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
Earthworm Nephridial Placement|Nutrient Cycling Reservoirs|Standing Crop quantification
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Integrating Animal Physiology (Excretory adaptations of earthworm) with Ecosystem Ecology (Nutrient cycling and standing crop).
Students often memorize the types of nephridia but fail to link 'enteronephric' with 'water conservation' and the production of 'nutrient-rich casts' that drive soil nitrogen mineralization.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Structural Organisation in Animals - Class 11 |
| Concept | Earthworm Nephridial Placement |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |