Expert: John Shea - 3/25/2005

Question
Hello John!

I have several questions:

1) Where and when did the Homo sapiens (archaic) evolve, and where had he migrate to?

2) Where and when did the Homo sapiens sapiens evolve?

3) How come the Homo sapiens sapiens is the only one that left among the Homo familiy? Or Why did the rest hominids got extinct, and we survived?

Sincerely,
Tom.

Answer
Hi Tom
All three are complicated questions, so I'll do my best with a quick answer to each.  Should you wish to learn more, consult any good college-level text on human evolution or visit either the Smithsonian or BBC web pages, both have excellent guides to human evolution.
1. origins of archaic Homo sapiens.  This is an old term, not much used among experts, for a group of fossils dating to between 700-200 Kyr (Kyr = 1000s of years ago).  For a long time, we did not have many groups of fossils from any one region during this period, and so paleoanthropologists began calling them "archaic Homo sapiens", implying that some of them were ancestral to us.  Nowadays, we have better fossil samples are recognize different regional species for this period, Homo heidelbergensis (Europe, W. Asia), Homo rhodesiensis (Africa), and others in Asia (including late-surviving Homo erectus).  The simple answer to your question is that these populations emerged from late Homo erectus populations that had dispersed into Africa and Eurasia some time after 500-700 Kyr.  We have not clear evidence for any of these new species migrating anywhere very far from their differnt zones of origination.
2. origins Homo sapiens.  Right now, both the genetic and fossil evidence point towards our species originating in Africa, probably East Africa around 150-200 Kyr.  At 195 Kyr, the fossils Omo Kibish in Ethiopia are the oldest-dated Homo sapiens fossils thus far known.
3. Why only Homo sapiens survives.  My opinion is that our ancestors developed such a broad ecological niche, aided by technology and complex social organization, that they out-competed all other hominid species that they encountered in dispersing from Africa.  Some species, like Homo floresiensis, seem to have persisted late in areas our ancestors were late to colonize, but other species, like the Neandertals, who inhabited ecozones more like those our ancestors inhabited in Africa disappeared very quickly once Homo sapiens shows up.  But, you have to keep in mind that species become extinct for many other reasons that competition.  Many Neandertal populations, and earlier species, may have died out as the result of rapid climate change, rather than competition.  We do appear to be on the end of a long-term trend over the last 4 million years in the reduction of species diversity among hominids. I guess we'd better be careful.
That's my take on the three questions you asked.  As I said, though, these are complex issues and there are, understandably, debates among experts about them.
Cheers,
John Shea