Final answer:
Anatomically modern humans, or Homo sapiens sapiens, have been around for approximately 200,000 years, with origins in Africa. They displayed physical traits similar to current humans and had spread to most of the globe by 40,000 years ago, after arising from predecessors such as H. erectus.
Step-by-step explanation:
Anatomically modern humans, known as Homo sapiens sapiens, are estimated to have been in existence for about 200,000 years. These early humans exhibited physical characteristics similar to those of people today, with rounded skulls, steep foreheads, an average cranial capacity of around 1,400 cubic centimeters, well-developed chins, and only moderately developed brow ridges. Fossil evidence shows that by 40,000 years ago, modern humans had spread throughout Africa, Asia, Europe, and Australia, and there is a consensus that they originated from Africa.
The debate on the emergence of anatomically modern humans is ongoing, as new fossil discoveries and genetic analyses continue to provide fresh insights. The predecessor of modern humans, H. erectus, had already migrated out of Africa and into Asia and Europe about 1.5 million years ago. It is thought that modern humans arose in Africa from H. erectus and made a second migration out of Africa approximately 100,000 years ago, during which they replaced earlier human species in Asia and Europe.
Understanding the timeline of human evolution is complicated by intermediate fossils found in Europe and Africa, which are dated between 300,000 and 800,000 years ago. These remains appear to bridge the gap between Homo erectus and modern humans but pose questions about earlier and later human forms. Further research is continually refining our knowledge of when anatomically modern humans first appeared.