Final answer:
Homo sapiens first appeared in Africa around 200,000 years ago and by 40,000 years ago, had spread globally except for the Americas, which were populated by humans between 16,000 to 13,000 years ago.
Step-by-step explanation:
The species Homo sapiens, to which all modern humans belong, appeared in Africa around 200,000 years ago. Early Homo sapiens were anatomically similar to people today with their rounded skulls, steep foreheads, and a cranial capacity averaging about 1,400 cubic centimetres. They are distinguished from their predecessors by the development of more sophisticated stone and bone tools, mastering the use of fire, and making clothing from animal skins which allowed them to adapt to various climates and spread globally.
There are two main models that explain the spread of Homo sapiens. The "out of Africa" model proposes that modern humans first emerged in Africa and then expanded, replacing other hominid species. In contrast, the multiregional evolution model suggests parallel evolution of Homo sapiens from Homo erectus in various parts of the world.
By about 40,000 years ago, Homo sapiens had spread throughout Africa, Asia, Europe, and Australia. It wasn't until between 16,000 to 13,000 years ago that they are believed to have arrived in the Americas, where they developed distinct agricultural practices and cultural traditions.