Question

Choose the correct answers from the alternatives given:
Which of the following is not characteristic of apes?

• A. Movement on the trees by brachiation
• B. Wrists that bend backward
• C. Movement on the ground by knuckle-walking
• D. Highly mobile shoulder joints

Answer 1

The correct option is B Wrists that bend backward

All ape species possess adaptations for climbing trees, as they all descended from tree-dwellers. This arboreal heritage of primates has resulted in hands and feet that are adapted for brachiation, or climbing and swinging through trees. These adaptations include:

1) A rotating shoulder joint.

2) A big toe that is widely separated from the other toes and thumbs, which are widely separated from fingers (except humans), which allow for gripping branches.

3) Knuckle-walking is a form of quadrupedal walking in which the forelimbs hold the fingers in a partially flexed posture that allows body weight to press down on the ground through the knuckles. It is seen in gorillas and chimpanzees.

4) Stereoscopic vision, two overlapping fields of vision from the eyes, which allows for the perception of depth and gauging distance.

However few features are exclusive to humans. The human hand is much more mobile than the primate hand. Humans can fully rotate their hands as well as extend and flex their hands at the wrist. Primates especially ape that walk on the knuckles of their hands are not as flexible with their hand movements. The wrist bones of the knuckle-walkers keep their hands from bending or extending while they put pressure on their knuckles.

Hence, the correct answer is 'Wrists that bend backwards'.