Final answer:
Early modern Homo sapiens evolved to have small jaws and teeth, a balanced molar size, and a more rounded skull with a less pronounced brow ridge than their predecessors. They were bipedal with humanlike feet and walked with a gait similar to that of modern humans. Significant changes included a larger brain, a well-developed chin, and the appearance of the canine fossa, a trait shared with modern humans.
Step-by-step explanation:
Anatomical Features of Early Modern Homo sapiens
The anatomical features of early modern Homo sapiens are distinguished from their predecessors by several significant characteristics. First and foremost, they developed small jaws and teeth, which reflect the changes in their diet and tool use. In contrast to australopithecines and some early Homo species that possessed a third molar larger than other molars, Homo sapiens had a more balanced dental size. Additionally, early Homo sapiens skulls began to resemble more closely that of Homo erectus or Homo habilis, albeit with modern human features like a rounded skull and steep forehead.
Another trait often found in Homo erectus, but also present in some Homo sapiens, was a sagittal keel—a small raised ridge on top of the skull. Despite these characteristics, early modern humans were unequivocally bipedal and walked with a humanlike gait, indicative of their well-adapted lower limb structure. Their feet showed humanlike features with arches and ankles that resemble those of contemporary humans.
Those identified as archaic H. sapiens, such as Homo heidelbergensis and Homo neanderthalensis, offered insight into our development with a larger brain size, averaging 1,200 to 1,400 cubic centimeters, yet they had thicker skulls and more pronounced brow ridges compared with the modern human's average cranial capacity. Over time, the brains of Homo sapiens increased in size, and significant changes in the cranium occurred, including the development of a well-defined chin and the reduction of heavy brow ridges. Transitioning from Homo erectus to Homo sapiens, anatomical features like a reduced prominence of brow ridges and a marked chin became more pronounced. The presence of a facial depression above the canine tooth, known as the canine fossa, also became a distinctive modern trait.