Final answer:
The first fossils of modern humans, Homo sapiens, appeared around 200,000 years ago with defining features like taller stature, rounded skulls, and a prominent chin. Their facial structure included a modern trait, the canine fossa. As human evolution progressed, facial and cranial features evolved, distinguishing species such as Homo neanderthalensis and Homo erectus from modern humans.
Step-by-step explanation:
First Fossils of Modern Humans
The first fossils that represent the physical characteristics of modern humans, or Homo sapiens, date back to approximately 200,000 years ago. These early humans had notable features that distinguished them from their predecessors. They were taller, had rounded skulls with steep foreheads, and an average cranial capacity of about 1,400 cubic centimeters. They also had well-developed chins, and their brow ridges were moderately developed in comparison to earlier hominids.
Facial Features of Early Modern Humans
One of the most fascinating aspects of early modern humans is their facial structure. They exhibited modern traits such as a facial depression above the canine tooth called the canine fossa, which is found in today's humans. Other anatomical features include a protruding occipital bun, a low forehead, and a cranial capacity of about 1,000 cc, as observed in species like Homo antecessor.
Evolution of Human Facial Features
Over time, human facial features have evolved significantly. Earlier forms such as Homo erectus had larger jaws and teeth, a sloping forehead, and a smaller brain compared to modern humans. Conversely, the Neanderthals, Homo neanderthalensis, who lived around 200,000 years ago, were stockier with flattish skulls and a pronounced brow ridge, exhibiting a larger brain volume than that of Homo sapiens.