Science a GoGo's Home Page Forums General Discussion General Science Discussion Forum All Humans Descended From Same Group

Ellis,
Thanks so much for listening. I'm sorry to have dredged it up, with so much very exciting (and wonderous) stuff to spend time on.

rede,
About the 110,000 dates in China. Modern humans came out of Africa (possibly continuously) during that period, but the thought is that they were wiped out; and only the groups that came out after 70,000 yr ago went on to spread and survive.

Roughly,
-gotta go watch Daily show..

Cool stuff though.
Thanks,
~Samwik

Rede. From your second link:

"the "out of Africa" dispersal of modern humans may not have been as simple as once thought...This morphological pattern implies that a simple spread of modern humans from Africa is unlikely"

As you note:

"I find conflicting affirmations of the time of the migration out of Africa."

Dates actually range between 200,000 and 40,000 years. To me this is a huge weakness in the single recent out of Africa model. If the model was correct we should have no trouble dating the migration. Perhaps many of us are influenced by the possibility of an ancient Moses.

I went to a lecture by Alan Thorne in Auckland in 2001. What he said then coincided with conclusions I had come to through transfering information about cattle breeding to human evolution. I agree with him that a date for Mungo man as recent as 40,000 years is irrelevant. It's still older than the more Homo erectus-looking Kow swamp fossils. Modern Aborigines appear to be a hybrid with neither extreme being still present. This is exactly what we would expect.

Regarding Mike's list. Leaving out Paranthropus, the specialised H. floresiensis and early East Asian fossils you get this order of evolution:

Australopithecus afarensis
Australopithecus africanus
Homo habilis
Homo ergaster
Homo erectus
Cro-Magnon man
Neanderthal man
Peking Man China.

H. ergaster and H. erectus are almost certainly just opposite ends of a cline that stretched from Southeast Asia, through China and the Middle East into Africa. Ergaster in Africa, erectus in SE Asia with other regions somewhere between. Subspecies at most. Humans have been moving back and forth through the world since they first evolved. This accounts for the regular replacement of mtDNA and Y-chromosome lines. These lines are much younger in humans than they are in most other mammals. As you say, Cro-Magnons may have "looked fairly identical to modern humans" but they certainly didn't look like modern Europeans. Modern Europeans have regained some Neanderthal traits. I wonder how they did that?

Hiya Terry,



Okay, I've been meaning get back about this. It was written at 3-4 am, so it sounds too blunt; and is a poorly written sentence (two disparate points related).

But you asked about why, so I wanted to point to the next line, "It's too limiting," as an answer.
Just the idea that a single gene (or even genes) could explain the fossil observations (and thus draw other conclusions) seemed to downplay other capabilities that the genome possesses, as well as other possible explanations of the fossils.

I enjoy thinking about anthropology and genetics, and I sure enjoy these threads. I wouldn't have felt comfortable being so loose with my language with many other people on these fora, and I think you know that; but I didn't want to leave that question hanging. Overall, at worst, it was written as an excuse to post those neat genome refs; and at best it was just a bad attempt to encourage more ideas about the topic.

Thanks for the Mungo info. too, everyone; I'd never heard about that stuff before.

~Later
~SA

Yes. That Mungo stuff is generally ignored because it doesn't fit the theory. You can prove anything if you ignore enough evidence.

Samwik. My bit about the genes not springing up overnight was, of course, because I agree with your comments regarding the complex interplay between genes.

Terry: "H. ergaster and H. erectus are almost certainly just opposite ends of a cline that stretched from Southeast Asia, through China and the Middle East into Africa. Ergaster in Africa, erectus in SE Asia with other regions somewhere between."

The Smithsonian chart (link below) shows H. erectus as having evolved from H. ergaster, apparently with no evidence of H. ergaster since well over a million years ago. Do you disagree with that?

http://www.mnh.si.edu/anthro/humanorigins/ha/a_tree.html

Thanks rede. I followed the link to H. ergaster and found this:

"By 1.9 million years ago, another lineage of the genus Homo emerged in Africa. This species was Homo ergaster. Traditionally, scientists have referred to this species as Homo erectus and linked this species name with a proliferation of populations across Africa, Europe, and Asia. Yet, since the first discoveries of Homo erectus, it had been noted that there were differences between the early populations of "Homo erectus" in Africa, and the later populations of Europe, Africa and Asia."

How much later? I think the last I'd heard was the other way round anyway, ergaster evolved from erectus in Africa. They're pretty near contemporaries because erectus had got to SE Asia at least soon after 1.9 million years ago. It's my guess erectus in Africa results from a back movement out of Asia.

Terry, your guess looks pretty good. From that same H. Ergaster link:

"By 1.6 million years ago, an advance in stone tool technology is identified with H. ergaster. Known as the Achulean stone tool industry, it consisted of large cutting tools, primarily hand axes and cleavers. Originally thought to be responsible for the spread of early humans beyond Africa, it is now known that the migration out of Africa predates this tool industry."

Maybe I'm missing something important, but this seems to be making a mockery of the significance of migrations 70,000-40,000 yrs ago.

As I said elsewhere I believe the "out of Africa" theory gains support from a wish to stress the complete separation of modern humans from other animals and even earlier humans. If we can believe we suddenly changed at some stage in our evolution it allows us to consider we are totally different to other species, and therefore special. The theory also fits ideas of a chosen group. There is a lot in our belief systems that encourages support for the theory.

If you're right, it's incredibly bad science. The contradictions appear to be so obvious for all to see. Can some of the smartest modern humans still be so bogged down by that kind of irrational anthropocentricity? Surely there's a valid argument for sticking to the late migration dates.

Red- When you have a nice elegant theory that enables interesting research and discussion to take place, and indeed, whole eminent careers to be built on it, why rock the boat. Science and other disciplines are full of examples of this. And the Out of Africa theory is tidy and emotionally appealing, so the tendency will be to iron out the irritating contradictions and have it all nice and flat and tidy again, in time for the next dig in the Rift Valley.

Good way of putting it Ellis. I wonder if I should mention it's my birthday today? Won't say how old.

Well, yes...I'm no stranger to cynicism - but if this particular issue is what it seems, then I'm frankly disgusted. It may be difficult for researchers to discover evidence, but I'm a complete greenhorn in this, and if I see what I think I see, how can a scientist tolerate such nonsense? Indeed, how can they live with themselves? There HAS to be something I'm missing...

HAPPY 75th BIRTHDAY TERRY

Redewenur wrote:

"if this particular issue is what it seems, then I'm frankly disgusted."

It's not a conspiracy, Rede. It's just that we're only capable of viewing the evidence through the lense of what we already believe. Old Testament myths and Victorian econmomics has settled deep within even atheists' subconcious. Your mission, should you accept it, is to now explain to people how evolution actually works. Good luck.

P.S. I've just put a comment on the Not Quite Science - Evidence for God thread you might like.

I don't hold with conspiracy theories in general, and I certainly don't entertain such an idea here. What I do, on consideration, find unlikely, is that the 'late migration' which could, at best, only loosely parody a defunct mythology, could be based on anything but concrete evidence. No, I'm convinced that I simply don't have enough data in my head just yet.

Rede,

You should check out page 2 of a thread called Neanderthal DNA illuminates split with humans [which is on page 8 of NQSci].

...from that thread.
"Anyway, I haven't looked at the links yet but do any of them refer to how all the populations that left Africa before 70,000 yr. ago were probably wiped out by the big volcano back then. Was it Tambura, in Indonesia? I'll go check the web, but there was a sort of "nuclear winter" back then which would explain why our diversity mainly traces back 70,000, except within Africa. Neanderthals probably did survive, being far enough away and better adapted. Basically, they could easily be the only [earlier] 'out of Africa' group, from our lineage, that survived the volcano.
~Sam" -15584

Toba, actually (the volcano).

There's also no reason that survivors in Asia might have then been replaced by the later emmigration from Africa ( as the Neanders were).

I'm not sure I still agree with all that I wrote back last Fall,
but there are a couple of good links to articles on the subject.
TerryT has a link on that page (which I was finally able to access with my newer computer). [~Later ttnz, ]

Cheers,
~Samwik

So were the Neanderthals involved in the migration through Asia. I had wrongly assumed that they were mainly in the Northern Hemisphere. I asked a while ago here whether any Neanderthal DNA had been recovered and the answer was, if I remember rightly, no. Has enough been analysed to be able to state confidently that their migration had been stopped by something when it is so uncertain where in fact they travelled, if at all?

Happy yesterday terry- I am sure you are ageless!

Thanks for the info, samwik. I've been reading about the 'YTT' Event. It is an intriguing suggestion that at least some of the earlier human migrant communities could have been eliminated. Whether or not it stands up to future research remains to be seen. Very interesting. I noticed in that earlier thread, "Neaderthal DNA...", good support for its placement in NQSci! (Keep up the good work Dr. Dawkins)

Ellis,
I was trying to find info about Neanders in Asia (guess not?), and came across this!

https://www3.nationalgeographic.com/genographic/atlas.html

...and their genographic project, newsletter, kits, etc.

Looks as if this is a new project (still kinda incomplete or i just don't know how to use it), but still lotsa info. Click on the slide at top of atlas to pick era < 200Kya.
Wow, will check out later....

-rede, there's a tab for Toba too.

Enjoy!
~SA

sam -The video wouldn't play but I'll try again when I have more time.

I'm pretty certain that it used to be agreed that Neanderthals were never in Asia or Australia, and it is in these areas that the most annoying aberrations seem to appear, eg, recently, Mungo and Flores.

Agreed Ellis. Neanderthals were a European evolutionary branch. There is disagreement as to how long ago they first appeared. Fossils dating to more than 200,000 years look Neanderthal but other fossils the same age in the region don't look Neanderthal. The gene pool narrowed over the millenia. But if you use a narrow definition of the Neanderthal type you finish up having to accept there were at least two, and really more, species of human living in Europe 200,000 years ago. About 70,000 years ago Neanderthals expanded into the Middle East, what is now Israel. They gradually retreated until the last pure looking ones died out in Spain perhaps as recently as 25,000 years ago.

Regarding the National Geographic link. It's not actually a video. Click on "Genetic Markers" or "Journey Highlights" at the bottom and check it out. You can follow any mitochondrial DNA or Y-chromosome line or look at any event in human evolution.

The site is very good. The distribution maps are especially great. I looked at the site quite a bit before I did my Adam and Eve thread (that's now on page 4 on the not quite science forum). But I'll make a few comments about the site because it illustrates my point.

If you check through either the Y-chromosome or mtDNA markers you'll notice that NG claims all the lines, apart from a few African ones, originate somewhere near the Middle East. This is actually unlikely to be the case. I'll start with the first one on the list, mtDNA haplogroup A. National Geographic claims the mutation occurred between the Caspian Sea and Lake Baikal. However most of her descendants now live in the Far East or America. Therefore almost certainly the mutation occurred somewhere in East Asia. I could carry on through both the mtDNA and Y-chromosome lists and find poblems with most of their arguments.

On their "Journey Highlights". Regarding Adam they say for a start that all humans are descended from him. They then say Adam was not literally the first man. What do they mean? Who did he have children with?