Final answer:
Anatomically modern humans are defined by characteristics like a tall stature, rounded skull, well-developed chin, low forehead, and adaptations for bipedal locomotion. They have a larger brain capacity compared to earlier Homo species, with an average size of about 1,400 cubic centimetres. Physical variations among modern human populations also reflect adaptation to different environmental conditions.
Step-by-step explanation:
Modern humans, classified as Homo sapiens, exhibit specific anatomical features that have evolved over approximately 2.8 million years. These characteristics are evident in the fossil records and distinguish us from our early ancestors as well as other members of the animal kingdom, particularly primates. Among the defining characteristics of anatomically modern humans are a tall stature with an upright bipedal locomotion, a rounded skull with a steep forehead, an average cranial capacity of about 1,400 cubic centimetres, well-developed chins, and only moderately developed brow ridges. Our anatomy includes a protruding occipital bun, a low forehead, and visible facial features like the canine fossa above the canine tooth. The skeleton of modern humans reflects adaptations to walking on two feet, evidenced by our broader pelvis, longer legs, and arched feet. The development of smaller jaws and teeth, reduced prognathism, and an increase in brain size over 600 cc also mark significant changes from earlier Homo species. Furthermore, differences in human biological variation, such as height, jawline, eye sockets, and skin pigmentation, have evolved in response to diverse environmental conditions and are used to evaluate physical similarities and differences between human populations over time and space.