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Question #46121
The Question
In metameric organisms like earthworms, the coelom acts as a hydrostatic skeleton where segmental musculature facilitates movement. In contrast, mammals exhibit a highly specialized respiratory mechanism. Which of the following best describes the anatomical and functional departure of mammalian ventilation from the primitive metameric body plan?
Options
- A.
Mammals retain metameric compartmentalization of the coelom, but utilize the diaphragm instead of circular muscles for generating a hydrostatic pressure gradient.
- B.
The mammalian diaphragm completely partitions the coelom into thoracic and abdominal cavities, replacing ancestral segmental body wall ventilation with a singular muscular partition.
- C.
Unlike annelids, mammals utilize a continuous, unpartitioned coelom where the diaphragm acts as a hydrostatic skeleton to facilitate negative pressure breathing.
- D.
The diaphragm is a modified metameric septum that maintains the primitive segmental continuity of the coelom while assisting the external intercostal muscles in expiration.
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
Diaphragm_Mechanics|Segmentation|Body_Fluids_and_Circulation
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between metameric segmentation (repeating units for hydrostatic locomotion/ventilation in lower invertebrates) and specialized regional compartmentalization (diaphragm for negative pressure ventilation in mammals).
Students often falsely equate the annelid septa with the mammalian diaphragm or assume mammals retain a continuous coelom for ventilation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Animal Kingdom - Class 11 |
| Concept | Segmentation vs. Metamerism |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |