Before You Begin
Question #47406
The Question
The human radiocarpal (wrist) joint is a condyloid synovial joint that allows biaxial movement. In cetaceans (e.g., whales), the forelimb is homologous to the human arm but functions analogously to a fish fin. Which of the following statements correctly identifies the structural modification of the carpal region in cetaceans to achieve hydrodynamic stability, and its evolutionary context?
Options
- A.
The carpal joints retain their ancestral condyloid synovial structure to allow complex steering, illustrating convergent evolution with cartilaginous fishes.
- B.
The carpal bones are rigidly bound by fibrous tissue, losing synovial mobility to form a stiff paddle, illustrating divergent evolution of the pentadactyl limb.
- C.
The wrist joint has modified into a highly flexible saddle joint to counteract high fluid pressure, demonstrating an analogous adaptation to aquatic life.
- D.
The carpal bones have completely degenerated and are replaced by cartilaginous rays to mimic the flexibility of a fish fin, showing convergent evolution.
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
Synovial_Joint_Varieties|Analogous_Organ_Structure|Hominid_Cranial_Capacity
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the functional analogy of the whole flipper (convergent evolution with fish fins) with the structural homology of its internal bones (divergent evolution from mammals).
A common misconception is assuming that aquatic appendages require highly flexible internal joints for swimming, failing to realize that hydrodynamic efficiency in cetacean flippers relies on a rigid, fibrously bound skeletal axis distal to the highly mobile shoulder joint.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Locomotion and Movement - Class 11 |
| Concept | Synovial Joint Varieties |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |