Final answer:
Biological anthropologists distinguish anatomically modern humans from archaic Homo populations by features such as the absence of a thick skull and prominent brow ridges, and the presence of a pronounced chin in modern humans. Brain size may overlap, but the shape of the skull tends to be different. These variations, along with others, are seen as adaptations to diverse environmental challenges over time.
Step-by-step explanation:
Biological anthropologists identify several key anatomical characteristics to differentiate anatomically modern humans from archaic Homo populations. Anatomically modern humans lack the pronounced thick skull and prominent supraorbital ridges (brow ridges) that are characteristic of archaic Homo. Moreover, modern humans have a distinct chin, which is not prominent in archaic species. Archaic Homo, which include species such as Neanderthals, had brain sizes averaging 1,200 to 1,400 cc, within the range of modern humans. However, their braincases often showed a longer and lower shape compared to the round, globular skull typical of modern humans.
The anatomical distinctions are underpinned by differences in environmental conditions that these species experienced. Archaic Homo populations may have seen evolutionary changes in anatomy and material culture due to various environmental pressures, including dramatic climatic shifts, which required rapid biological and cultural adaptation.
In the field of biological anthropology, researchers compare fossilized remains and genetic data to understand the evolution of early hominins and the emergence of traits that are unique to modern humans, such as language capabilities. While there is ongoing debate about the precise ways environmental factors shaped human biology and culture, it is clear that the genus Homo developed a remarkable ability to adapt to diverse environments.