Final answer:
Human craniums and dentition are distinguished from those of chimps by higher cranial capacity, smaller front teeth, upright posture, shorter arms, and increased dexterity of hands. Despite close genetic ties, anatomical differences are significant, including less protrusive jaws and different limb proportions in humans.
Step-by-step explanation:
The differences in cranium and dentition between chimps and humans can be characterized by several features. Humans have small front teeth, which includes the canines and incisors, and very large molars when compared to other primates. Our cranial capacity is significantly larger, approximately 1,400 cubic centimeters (cc), while a chimpanzee's is about 350 cc, similar to the found remains of Sahelanthropus tchadensis, which lived about 7 million years ago (MYA). Humans also have a fully upright posture, which leads to bipedalism; consequently, our arms are shorter relative to our legs when compared to chimpanzees, and our hands are more dexterous.
Chimp jaws, as seen in Figure 12.7, protrude much more significantly than human jaws. Australopithecines, which existed before modern humans, show a combination of traits, such as bipedalism and human-like feet, yet they had larger teeth and a more prominent jaw. While humans and chimps are very closely related genetically, our anatomical differences, such as jaw protrusion and limb proportions, are considerable. Early human ancestors like Homo habilis also demonstrate increasing brain size and the use of tools.