Question

Many of the earliest hominins retain some features that would be helpful for tree climbing while also exhibiting derived features of bipedalism. Which of the following is a typical set of features you might see in the earliest hominins?

A) Large, curved fingers and toes, and long arms relative to legs
B) Large canines, a pronounced diastema, and quadrupedal locomotion
C) Reduced jaw size, brain expansion, and a forward-facing foramen magnum
D) Reduced thumb opposability, digitigrade feet, and large body size

Answer 1

The typical features of the earliest hominins include large, curved fingers and toes, long arms relative to legs, and adaptations for bipedalism, like a broader pelvis and longer legs. Over time, other traits such as reduced canine size, increased molar size, and larger brain size also developed.

Step-by-step explanation:

Among the earliest hominins, the typical set of features you might see include: A) Large, curved fingers and toes, and long arms relative to legs. This feature set signifies a transitional phase where hominins retained arboreal adaptations suggestive of their tree-climbing ancestry. However, over time, traits evolved to favor bipedalism, such as a broader pelvis, longer legs, and arched feet, indicative of efficient bipedal locomotion seen in species like Homo erectus. Other features such as smaller canine teeth compared to other primates, large molars, bipedal locomotion, and a progressive increase in brain size, especially in the frontal lobes, were also present in early hominins. These characteristics reflect a significant shift away from a tree-dwelling lifestyle towards one that is more adapted to life on the ground.