Comments on: The end of "archaic" H. sapiens

By: Mike McNally

Mike McNally — Mon, 19 Sep 2011 15:06:14 +0000

As a complete ignoramus (but also an avid reader), I have some curiosity about the implications of the 35,000ya “split” between European and East Asian humans, and it’s this: though we don’t know who it was, it’s clear that *some* group of humans produced cave paintings in Europe that (in some cases) date to approximately the same time. If there was some sort of population separation that happened at roughly that same time, does that imply that the progenitors of today’s East Asians wandered eastward from the opposite end of the land mass? Or could it mean that a (presumably pretty widely-scattered) genetically coherent group was somehow forcibly split by (say) climate change?

I’ve been reading a lot about migration dynamics since I started reading this blog (incl. Peter Heather’s “Empires and Barbarians”) but issues like this still leave me scratching my head in search of some comprehension. Of course I realize that a conclusive answer is probably unavailable.

By: Jean M

Jean M — Mon, 19 Sep 2011 12:57:52 +0000

we should be cautious about inferring a qualitative difference between Neandertals and AMH, where the former is bracketed as “archaic”.

Archaic does not refer to time period, but to anatomy. Neanderthals and early AMH shared parts of the planet, as we are all hearing on a regular basis these days. That chronological crossover makes no difference to their anatomy. They were different from Homo sapiens. In fact Neanderthals had developed many of these differences outside Africa. They are on a separate branch-line from Homo sapiens and not ancestral to them.

The earliest AMHs were exactly that, no matter what their age. They were Homo sapiens anatomically and our ancestors.

By: Eurologist

Eurologist — Mon, 19 Sep 2011 05:12:17 +0000

Finally a paper with somewhat more reasonable dates — although again, only the oldest ones within the given intervals and methods make sense. Using the oldest human-pan divergence time (7.6 Mya) leads to an intra-African split at 147–157 ka.

Climate was very cold and dry between ~140,000 – 160,000 ya – the *beginning* of this period is certainly a plausible time for a split into two isolated populations in Africa. Furthermore, during the subsequent wet and warm phase 115,000-130,000 ya (Green Sahara and a likely wet South Africa) these populations would have undergone separate growth, fixing their differences.

The oldest Pan-human divergence time (7.6 Ma) also leads to an ooA time that is more believable (51 to 64 ka) than earlier divergence times. Climate was reasonably warm and wet before about 70,000 ya; so again, the oldest possible date within the intervals and methods (perhaps plus 10-20%) makes some sense.

The oldest time (from all intervals and methods) for the European-Asian split is 44,000 y, which of course makes perfect sense, given the European fossil record (well, again, adding 10-20%, given that the population split before migration, and considering an earlier exodus to SE Asia).

As to Neanderthals, I have stated on numerous occasions that heidelbergensis and Neanderthal of course had the same periodic (~50,000 or 100,000 y) warm/wet climatic opportunities to meet with Africans in the Levant and in North Africa, and exchange genes. So, I find the apparent “convergent evolution” during the past ~million years no surprise. However, the event 250,000 ya was unusually brief and may not have helped. The last one before is 350,000 ya – matching the purported Neanderthal-AMH split perfectly (well, again, the oldest one within the interval).