Michael:

I’ve been reading an interesting book, “The Journey of Man: A Genetic Odyssey” by Spencer Wells. (This can be bought here.) Wells, a former postdoctoral fellow of Luca Cavalli-Sforza’s at Stanford, uses genetics to lay out the general migrations of anatomically modern humans out of Africa and across the world over the past 50,000-60,000 or so years.

Granted, it may be exaggerating a bit to call Mr. Wells’ (Dr. Wells, one presumes) reconstruction “history” at this point, as his account is not based on written records. Nonetheless, it would appear—assuming that he and the rest of the scientific community has done their work right—that we now possess a sort of roughed-in view of what’s been happening over that time span.

And because we believe in public service here at 2blowhards, we’ve decided to share a brief outline with you. Making only one, albeit much larger, assumption: that I’ve succeeded in taking accurate notes from his book, the following maps should give you some ideas of how and when the various parts of the globe were inhabited. Remember, there will be a quiz.

Please note: the red ellipses represent the areas historically populated by anatomically modern humans at roughly the date shown, while the green ellipses are the new areas being colonized at that time. Neither set of ellipses attempts to show the precise area of settlement or the size of the population that it contains; heck, they’re entirely schematic. In fact, the word “population” might be a gross overstatement in this case. Some of these migrations may have been undertaken by ludicrously small groups of people, at least by modern standards. To take one example, a breeding pool of a mere 10 or 20 individuals crossing the land bridge into North America 15,000 years ago could have provided for all the existing genetic variety of modern Native American populations. North America may have been 'settled' by a group of no more than a few hundred people.

Map #1—c. 60,000+ Years Before the Present

Anatomically modern humanity is confined to Africa, where it arose from 300,000 to 160,000 years ago.

Map #2—c. 50-60,000 Years Before the Present

The first group to head out of Africa (which was apparently suffering drought) did so by taking the “beach” route along the South Asian coast and reached Australia in remarkably short order. This was the easiest road out of Africa at the time as sea-level was 100 meters lower than today because of the Ice Age. Consequently, many modern water barriers—like the Persian Gulf —were river deltas and passable on foot. Also, the skills necessary to survive in a coastal setting had been mastered by anatomically modern humans in Africa and were easily transferable to their new geographical setting. (Venturing into the interior of the Eurasian landmass, with its largely temperate climate, would involve developing a whole new set of hunting and gathering skills, and was thus a much tougher nut to crack.)

Map #3—c. 45,000 Years Before the Present

Brief, wetter periods when the Sahara would have been more hospitable may have enticed settlers into the coastal regions of North Africa. However, when the climate became abruptly drier, the anatomically modern humans had to leave--fast--and found that an extremely nasty barrier of sand now barred their return. This may have forced our ancestors to make the first successful effort to settle the Levant, the Eastern shore of the Mediterranean.

Map #4—c.40,000 Years Before the Present

By this period, anatomically modern humanity has penetrated east to the plains of Iran. Smallish groups of anatomically modern humans (known as the Chattelperronians from their distinctive stone toolkit) attempted to colonize Europe via the Balkans, but seem to have had only very limited success.

Map #5—c.35,000 Years Before the Present

Anatomically modern humanity got serious about spreading out. Their previous eastward advance was blocked by the three giant mountain chains of central Asia (the Hindu Kush, the Himalayas, and the Tien Shan.) Reasonably enough, the ‘pioneers’ split up. One group went north to Central Asia, a second group went south to India, and a third group with serious wanderlust seems to have made it through the Dzhungarian Gap into Western China and eventually all the way to Korea and Japan. The Australian group, sticking with their coastal ways, also chose this era to expand up into East Asia along the ocean route. (Interestingly, they didn’t encounter more primitive hominids, which had died out in East Asia, possibly from a changing climate, long before anatomically modern humanity left Africa.)

Map #6—c.30,000 Years Before the Present

The Central Asian ‘clan’ apparently followed the steppe band across Asia and into what is now Germany, thus becoming the parents of modern Europeans. They seem to have arrived in force and swamped both the Neanderthals and the small numbers of anatomically modern humans already living there (the Chattelperronians), driving the first to extinction and the absorbing the latter.

Map #7—c. 20,000 Years Before the Present

That ultra-mobile Central Asian ‘clan’ colonized the Southern Siberian zone and moved eastward to the shores of the Pacific Ocean.

Map #8—c. 15,000 – 10,000 Years Before the Present

Hey, things suddenly go crazy! Let’s do this by the numbers, first clicking on the pop-up map so you can see the detail better: #1: Neolithic farmers from the Middle East carry agriculture into Europe along the Mediterranean. #2-#3: Members of the European Clan speaking PIE (proto-Indo-European) and having developed a horse-based (chariot) culture expand eastwards across Russia, move into Iran and ultimately invade India. Genetics suggests that this was accomplished with relatively small numbers although the cultural impacts were obviously great. #4: North Chinese agriculturalists, having domesticated rice, increase substantially in population and ‘invade’ southern China. #5: The Australian Clan, possibly pressured by the invading North Chinese agriculturalists, continues to move north to Siberia. #6: The Australian Clan then colonizes North America, apparently by boat, where its descendants are most numerous in the Western United States. This probably happened somewhat later than #7: the branch of the Central Asian clan living in Southern Siberia followed a land bridge first into Alaska and eventually crossed the Canadian glaciers and spread out through the remainder of the Americas. This group made the greatest genetic contribution to modern Native Americans in North America and is exclusively responsible for the native American population of South America.

So that’s simple enough, right? We managed it in a lot fewer words than the account in Genesis, anyway.

Speaking of Genesis, there are a number of parallels between the Biblical account and Mr. Wells’ account. Both, for example, cover the period between the historical ‘present’ and the birth of humanity’s common male ancestor, known as ‘Adam.’ (According to what Mr. Wells refers to as ‘absolute’ genetic dating methods, it appears that this figure lived approximately 60,000 years ago in Africa.)

Granted, the Bible’s 6,000 year-span from Adam to the ‘present day,’ has been expanded, but only by a mere 10-fold. The resulting 60 millennia are really, in comparison to geologic or astronomical time, quite a humanly graspable span. It’s odd that 150 years of science has somehow brought us back so close to where we started.

Heck, maybe this new account will form the basis of a new literary and cinematic genre: sort of a Paleolithic Western: How the World Was Won.

“Okay, boys, cue the Mammoth stampede!”

“Yes, Mr. Ford.”

Cheers,

Friedrich

Are you referring to the Elohist creation account in Genesis 1 where the world and all plant and animal life are created in five days, and God makes "men and women" together on the sixth?

Or are you referring to the Yahwist creation account in Genesis 2, in which Adam is created first (not in Africa per se, but somewhere around present-day Iraq) and the other animals emerge from a mist on the ground?

Posted by: Tim Hulsey on April 20, 2004 1:10 PM

Well, I like to keep my options open. Remember, consistency is the hobgoblin of small minds...

Posted by: Friedrich von Blowhard on April 20, 2004 1:14 PM

Thanks. Most helpful.

One caveat is that recent evidence suggests that the population of Australia wasn't quite so anomalously early as was previously believed. Certainly the Indian Ocean shore route was very important at the beginning of the Out of Africa surge, but the "express train to Australia" model isn't really necessary if the new dating of Australian remains as not quite as old stands up. More likely, people got to Australia at a more reasonable pace.

Posted by: Steve Sailer on April 20, 2004 5:04 PM

Isn't this kind of stuff fasincating ? Its interesting that Spencer Wells is using the Clovis date for the settlement of the Americas, and your diagram shows the settlers coming exclusively over the land bridge from Asia.

I was under the impression - although I should point out that I'm a total amateur here - that the most recent evidence pointed to several migrations, with the oldest probably being in 30,000 years BP, and from several different sources, including Ainu-like people from Asia, and people from Western Europe. There are, for instance, traces of European mitochondrial DNA in the native American population pool that date back to 20,000 BP or so. Given that evidence, several scholars now seem to be working on the assumption that the Clovis culture, with its characteristic blades, was linked to the Solutrean culture in Europe where they had similar flint working techniques.

It seems the whole Clovis/pre-Clovis thing is still controversial with many archaeologists, but from my utterly uninformed perspective it looked as if the evidence - genetic and archaeological - was starting to pile up againt Clovis being the earliest migration. Does Wells not mention the pre-Clovis arguments at all ?

Posted by: Simon Kinahan on April 20, 2004 5:14 PM

I am, obviously, completely unqualified to opine on the accuracy of Mr. Wells' account. Here, however, are two quotes from him on the dates of settlement of Australia:

...a man was buried [at Lake Mungo in Australia.] Called Mungo 3 by his discoverer, Jim Bowler, the find was dated to around 30,000 years ago when it was discovered in 1974. More recent dating methods have pushed the age back to 45,000 years, and human artefacts from sedimentary layers below Mungo 3 hint at dates as ancient as 60,000 years before the present. If confirmed, these dates will make Mungo the earliest site in the world outside Africa to be inhabited by anatomically modern humans.

And:

Richard Roberts and his colleagues at the Australian National University, investigating the relatively unsophisticated tools used by these early [settlers], have inferred dates as great as 60,000 years ago for one site in the Northern Territory.

On the controversy over the settlement date of the New World:

In the 1970s and 1980s, though... archaeological digs... turned up evidence for a human presence before Clovis. The Meadowcroft Rockshelter in Pennsylvania yielded artefacts that were originally dated using radiocarbon to roughly 14,000 years ago, predating Clivis by 3,000 years. The care with which Meadowcroft was excavated was impressive and while the dates for the earliest occupation have been revised downward (to around 12,500 years ago), they are accepted by many anthropologists. The site at Monte Verde in southern Chile yielded similar dates to those at Meadowcroft, roughly 13,000 years, although nearby hearths have been estimated to be as old as 33,000 years. The earlier date has not been widely accepted, and thus Monte Verde is thought to date--like Meadowcroft--to around 13,000 years ago.

And his contribution to the debate, which utilizes genetic polymorphisms on the Y chromosomes (given "M" numbers to identify them):

A recent analysis of the M45 lineage by Mark Seielstad and myself has defined a further marker, known as M242, which is a descendant of M45 [the key polymorphism identifying the Central Asian clan.] It appears to have arisen in central Asia or southern Siberia around 20,000 years ago, and is distrubted across Asia...as well as throughout the Americas. It is found at highest frequency in Siberia...It is also immediately ancestral to M3 [the key polymorphism for most North American and all South American Native Americans]...M242 appears to be the oldest genetic marker in the Americas...Clearly an entry prior to 20,000 years ago is inconsistent with the genetic results, since M242 was still in Central Asia at that time. A more recent migration from Siberia is overwhelmingly likely, consistent with the archaeological evidence...[Even once in the New World, however] these first Americans of 15-20,000 years ago had one more obstacle to overcome. They would almost certainly have been barred from southward expansion by a continuous sheet of ice that covered most of northern Canada and eastern Alaska. It was only as the ice age began to abate, after 15,000 years ago, that it would have become possible to transit the formerly icy interior and enter the North American plains...It is around this time that grizzly bears first enter North America from Siberia, showing that humans weren't the only species to have been stopped by the Alaskan ice.

Hey, even if Wells isn't the last word on this subject, you have to admit this stuff is very interesting, no?

Posted by: Friedrich von Blowhard on April 20, 2004 9:02 PM

Oops, forgot something:

There are, for instance, traces of European mitochondrial DNA in the native American population pool that date back to 20,000 BP or so. Given that evidence, several scholars now seem to be working on the assumption that the Clovis culture, with its characteristic blades, was linked to the Solutrean culture in Europe where they had similar flint working techniques.

This sounds fascinating, but I have to wonder; given that in Mr. Wells' account the dominant strain of Native Americans and the Europeans both are 'descendants' of the Central Asian clan, isn't it possible that such genetic and cultural similarities arose without needing European immigrants to spread them? Maybe we should try to contact Mr. Wells via Random House and put the question to him!

Posted by: Friedrich von Blowhard on April 20, 2004 9:12 PM

Good lord, well done, thanks.

Posted by: Michael Blowhard on April 20, 2004 10:47 PM

Has anyone written a SF story about how the Australians got to Australia so early on yet?

Posted by: Tracy on April 21, 2004 12:09 AM

Stephen Baxter, noted British SF writer, has written a novel called "Evolution" (amazon link: http://www.amazon.com/exec/obidos/tg/detail/-/0345457838/qid=1082528229/sr=1-1/ref=sr_1_1/103-8118362-0295007?v=glance&s=books). It reconstructs humanity's key migrations, including the early human island hopping to Australia.

Posted by: Zachary Latif on April 21, 2004 1:40 AM

Fascinating! You've made me really want to go out and buy the book myself. Thanks much!

Posted by: Robert the Llama Butcher on April 21, 2004 11:14 AM

Interesting stuff. However, I was struck by your use of "Humanity" and "Native American" instead of "Man" and "Indians" or perhaps "American Indians" or even "Amerinds". A "Native American" is of course, anyone who is born in America, not just an Amerind. Irrational. Well, at least you didn't use BCE instead of BC, avoiding that silliness by using "Before the Present". Makes more sense when you're talking about events before 3000 BC or so. As to the chronology, has anyone got a guess why Man arose in Africa? Reminds me of the question as to whether there is life elsewhere in the universe. Why couldn't life have arisen first on this planet if Man could originate in one small part of this world? Tempting analogy, eh?

Posted by: Robert Speirs on April 21, 2004 2:05 PM

Thank you very much for quotes from Wells book, Freidrich. Sounds like I'm a bit out of date. A view that is confirmed by this recent paper (unfortunately in PDF), which classifies some of the speculation about a Solutrean-Clovis link, with classic academic contempt, as "premature". It would appear that the "X" mtDNA marker thought to be present only in Europe and North America is also present in Siberian populations around Lake Baikal.

Posted by: Simon Kinahan on April 21, 2004 3:59 PM

Take a look at Out of Africa and back as "Mongoloids" on:

http://klevius.info/Humandiaspora.html?1085339285543

and, pleae, contribute constructively to this free, new and rudimentary site.

Posted by: Peter Klevius on June 25, 2004 3:59 PM






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