Final answer:
Le Gros Clark identified three primary tendencies of primates: a rotating shoulder joint allowing for brachiation, the presence of separated big toes and opposable thumbs for better grip, and stereoscopic vision for depth perception. These features have contributed significantly to primate evolution.
Step-by-step explanation:
The three main primate tendencies defined by Le Gros Clark, which are evident in various primate species including ourselves, encompass several key adaptations derived from their arboreal heritage. These traits have been crucial in the context of primate evolution.
- Rotating shoulder joint: This adaptation allows primates to have a wide range of motion in their arms, facilitating climbing and brachiation.
- Separated big toe and opposable thumbs: Apart from humans, primates have a big toe that is widely separated from the other toes, and opposable thumbs, which are separated from the fingers, enhancing their ability to grip and manipulate objects.
- Stereoscopic vision: Primates have two overlapping fields of vision that allow for depth perception, which is vital for assessing distances when navigating through the trees.
In addition to these adaptations, primates have other distinctive traits such as large brains relative to body size, nails instead of claws, usually giving birth to one offspring at a time, and a tendency to maintain an upright posture.