Final answer:
Anatomically modern humans refer to early Homo sapiens with physical traits like ours who emerged around 200,000 years ago. They evolved from Homo erectus, passing through intermediate species such as Homo heidelbergensis and Homo neanderthalensis, with gradual changes in brain size and facial structure.
Step-by-step explanation:
Anatomically modern humans are those early members of the species Homo sapiens who are virtually indistinguishable in physical traits from contemporary humans but may not have exhibited what we consider modern behaviors. They emerged approximately 200,000 years ago and had characteristics such as rounded skulls, steep foreheads, an average cranial capacity of 1,400 cubic centimeters, well-developed chins, and moderately developed brow ridges. This period marked the transition from Homo erectus to more anatomically modern forms, leading eventually to humans with smaller faces, jaws, and teeth, but significantly larger brains.
Over time, several species evolved from H. erectus, including Homo heidelbergensis, Homo rhodesiensis, and Homo neanderthalensis, which are classified as archaic Homo sapiens. These species existed until about 30,000 to 10,000 years ago and had brain sizes similar to ours but featured thicker skulls and prominent brow ridges. Throughout this evolutionary journey, fossil evidence shows various intermediate forms between H. erectus and modern humans, with notable specimens such as Homo antecessor showing traits that overlap with modern human anatomy.