Final answer:
The dental arcade of modern humans is parabolic, a reflection of evolutionary changes related to diet and brain development, while that of apes is U-shaped, suitable for their fibrous plant-based and omnivorous diets that require different dental structures.
Step-by-step explanation:
The dental arcade of modern humans is parabolic, while that of apes is U-shaped. This distinction reflects the evolutionary changes in skull and jaw shape that accommodate different dietary habits and the development of speech in humans. Over time, Homo sapiens evolved with smaller faces, jaws, and front teeth, but with much larger brains compared to earlier Homo species. Our ancestors' transition to cooking food and eating a diet with processed, low-fiber contents has led to smaller teeth and jaws in humans compared to other apes that consume more fibrous plant material and occasionally meat, thus requiring different dental structures.
Australopithecines, an early hominid species, show a variety in tooth and jaw morphology, with some having robust features to chew tough plant materials, while others had smaller teeth and jaws. Modern human dentition consists of small front teeth (incisors and canines) with relatively large molars compared to other primates. This is partially due to the change from a herbivorous and omnivorous diet to one that includes a significant amount of cooked and processed foods. In contrast, most primates have a heterodont tooth structure that includes different types of teeth modified for ripping or grinding food based on their diverse diets.