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Question #46398
The Question
Aquatic birds such as penguins and ducks spend a significant portion of their lives in water-abundant environments. However, unlike aquatic amphibians or bony fishes, they excrete nitrogenous waste primarily as uric acid. Which of the following best explains this physiological phenomenon?
Options
- A.
Ammonia has a large molecular weight and cannot be effectively filtered by the avian glomerulus, forcing its conversion to uric acid.
- B.
The uricotelic pathway is phylogenetically locked due to the evolutionary requirement of the cleidoic egg, despite uric acid synthesis being highly ATP-intensive.
- C.
Uric acid synthesis requires significantly less metabolic energy (ATP) than urea synthesis, providing an energetic advantage in cold aquatic habitats.
- D.
Aquatic birds lack the Loop of Henle in their nephrons, making them incapable of concentrating urea and necessitating the excretion of uric acid.
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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
Uricotelic Birds|Adaptive Radiation Logic|Evolutionary_Strategy
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often mistakenly believe that an organism's excretory product is dictated solely and immediately by its current habitat's water availability.
This question tests the 'NCERT-Plus' understanding that evolutionary history (the cleidoic egg) creates irreversible metabolic pathways, forcing aquatic birds to bear the high ATP cost of uricotelism even when water conservation is no longer a strict ecological necessity.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Excretory Products and Their Elimination - Class 11 |
| Concept | Nitrogenous Waste Classification |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |