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Sunday, August 16, 2015

Prehistoric (?) Man, Part III

I should make clear, I'm no expert on human evolution. I don't know which branches of the family tree contributed to the current gene pool, and which turned out to be dead ends. I'm merely an interested layman trying to learn about it.

But the more I read, the more it becomes apparent that the experts don't really know all that much, either. Virtually every major aspect of human evolution is still a subject of debate. For instance, we now know that all non-sub-Saharan peoples average between 1 and 4% Neanderthal genes. But why did the Neanderthals disappear? Were they killed by the Cro Magnons or simply absorbed into their gene pool?

Likewise, no one is really sure whether Homo erectus originated in Africa and then migrated elsewhere, or whether he evolved in Asia and then migrated back to Africa. There are also differing opinions on whether Homo erectus is in fact the same species as Homo ergaster. If so, then it seems much more likely that Homo erectus was a direct ancestor of Homo heidelbergensis, Neanderthals, and Homo sapiens (us).

But, no one knows for sure.

A more emotionally-tinged topic seems to be, how long ago did the current races separate? Was it closer to 50,000, or 200,000 years ago? The debate continues.

In any case, I don't even know enough to have an opinion. All I can do is look at the forensic reconstructions from the skulls of primitive man and marvel at the directions evolution has taken us. Sometimes, I also marvel at how much similarity "primitive" man has to modern day humans.

A few examples of the latter:

An artist's reconstruction of a Neanderthal:

American singer, pianist, comedian, and actor Jimmy Durante:

Here is an actual life mask of Durante's face:

Another artist's conception of Neanderthal man --

-- who looks like a cross between pro wrestler Triple H --

-- and Beach Boy Dennis Wilson:

Another conception of Neanderthal --

-- who resembles Javier Bardem:

A Neanderthal --

-- who somehow looks like John Amos:

A Neanderthal --

-- who looks like Charlton Heston:

This Neanderthal --

-- could be a slightly older version of Feral Boy from Road Warrior:

And this Neanderthal --

-- bears a passing resemblance to actor Robert Forster:

Even earlier species of Homo look a little like modern people. This Homo erectus --

-- does not look all that different from a modern day Australian aborigine:

Other early humans call to mind various recent celebrities. This Homo ergaster --

-- has the same vestigial sagittal crest as actor Michael Clarke Duncan:

This Homo ergaster --

-- has a sneer not unlike Gary Coleman's:

This Homo erectus --

-- calls to mind both Patrick Ewing --

and Willem Dafoe:

This Homo erectus --

-- bears a resemblance to Pablo Picasso:

This Homo erectus --

-- looks a little like Don Cheadle:

And this picture of a modern human with a Homo erectus looks --

-- a little like two boxers facing off while receiving their instructions at the start of a match. (Somehow you just know the guy on the left is going to lose.)

The official line is that all of these early precursors to mankind have disappeared. But is it really that clear?

It doesn't seem entirely coincidental that most of the Neanderthals call to mind various whites, whereas the representations of Homo ergaster and Homo erectus make one think mostly of various blacks.

The more I look at these pictures, the more I see the current racial tensions as not so much as the Jets vs. the Sharks from West Side Story, but as Neanderthals vs. Cro Magnons, Part II. It's happening in slow motion; but that's how evolution always appears to those undergoing it.

(One wonders if the Neanderthals ever had a leader, like Bill Clinton, who said he looked forward to the day when his type was in the minority.)


Steven said...

We apparently only have 1-4% neanderthal dna. If a white person had 4% African dna, you wouldn't be able to tell by looking at them, would you? Not usually, anyway...So how can we look so similar to neanderthals and do we really?

IF modern European features have an extensive similarity to neanderthal features, could that be because both they and us adapted to a cold climate?

I'm sure that modern Europeans are genetically much closer to modern Africans than to neanderthals, and modern Africans genetically closer to modern Europeans than to ergaster/erectus. Not just genetically but in skull shape. Africans will have some greater facial similarity to ergaster based on both being adapted to a tropical climate but in reality their skulls will be much more like ours than like ergaster skulls.

Finally, by comparing the whites that looks like neanderthals and the blacks that look most like ergaster/erectus, you may be looking at the more archaic looking whites and blacks rather than the average.

John Craig said...

Steven --
That 1 to 4% figure is why it's so striking that whites look so much more like these artists' conceptions of Neanderthals: there must be something more at play here.

The differences you're talking about -- the adaptation to tropical climates which are also shown by Melanesians, who aren't closely related to sub-Saharan Africans -- are the superficial ones, like darker skin and wider nostrils. There are more basic differences between the races which have nothing to do with climate. First, blacks have more prognathous faces (where the teeth are set further forward than the forehead) than whites; this was also a trait of Homo erectus. And second, brain size: Asians have an average brain size of 1364 cubic centimeters, white 1347, and blacks 1267. These correlate with the average IQ's of the races, respectively, of 106, 100, and 85 (this last number is for American blacks; African blacks average significantly lower). And this also correlates with skull size: corrected for body size, Asians have skulls an average of 3 cubic inches larger than Europeans, who in turn have 5 inches more cranial capacity than Africans.

Yes, I used examples of artists' renderings which reminded me of (mostly specific) modern day people. But I suggest you Google-image "Homo erectus," "Homo ergaster," and "Neanderthal," and see what your general impression is.

Gilbert Ratchet said...

Could you fix:

I should make clear, I'm no human evolution.


It doesn't seem entirely coincidence that most of the Neanderthals...


John Craig said...

Gilbert --
Will do, thank YOU.

Steven said...

Hi John,

I never said that Europeans and Africans never differed. I'm well aware of the numbers you quoted. I just said that modern Europeans and Africans are genetically and morphologically more alike each other than they are like prehistoric hominid species you are comparing them to.

Using your stats, assuming they are correct: white 1347; black 1267; ergaster 700-900, later specimens 900-1100. Its not just size but European's and African's skull shape is radically more similar, especially the cranium and brow. I doubt you could mistake an ergaster skull for a modern African one but you could mistake a modern African one for a European one. Though you can often tell race from skull, I don't think its always possible.

Africans are more prognathous than Europeans and prognathism is an archaic trait, that's true. But even in this trait, I would bet that the average modern African has a degree facial flatness than is closer to the average modern European than the average ergaster (certainly the earlier ones). Some Africans have prognathism that appears quite extreme and looks archaic but many Africans have only a small degree of prognathism or practically none at all.

When we see ergaster prognathism, yes, it definitely brings to mind the more prognathous of the modern Africans, and their facial features are certainly alike, due to climate. I totally get what you are seeing. Nevertheless, I'd maintain that an average modern African is a lot more like me than like ergaster (skin colour and nose shape notwithstanding.)

If you compare a particularly archaic looking African with a late ergaster, they might be more similar then.

As for neanderthals, these are the kind of reconstructions I trust and hold to be typical:

As for the following guy, he does looks very like a modern European to the point where he could fit in:

But why does he look so different to the other neanderthal reconstructions? If neanderthals and cro-magnon interbred, you could be looking at a cross breed! Or are we looking at early and late neanderthals and modern Europeans have more late neanderthal dna than we currently think?

Here is cro-magnon:

(Cro-magnon man was handsome).

Mark Caplan said...

Steven wrote: "We apparently only have 1-4% neanderthal dna. If a white person had 4% African dna, you wouldn't be able to tell by looking at them, would you? Not usually, anyway...So how can we look so similar to neanderthals and do we really?"

There is a fundamental confusion going on here, which I recognize but don't have the education in genetics to straighten out.

Half my DNA came from Mom and half from Dad. Or 25% from each of my four grandparents. Or 12.5% from each of my 8 great grandparents. Or 6.25% from each of my 16 great great grandparents.

So one great great grandparent contributed about as much to my DNA as my Neanderthal ancestor from 40,000 years ago.

See what I'm getting at? The 4% Neanderthal DNA must be fundamentally different in effect from the 6.25% DNA from my great great grandparent. The contribution from even more distant ancestors becomes vanishingly small, while the DNA from extremely distant uncle Neanderthal somehow remains constant.

Steven said...

...actually I'm not sure about the facial flatness part, though at the cranium where it counts most we are definitely very much more similar.

It is worth noting that many modern Africans have not much prognathism.

Here at three photos I found quickly from one search:

All flat faces, not unusual for Africans.

John Craig said...

Steven --
Okay, first, if I put words in your mouth, sorry. But the traits you originally mentioned were the more superficial ones. As far as primitiveness goes, whites have several I've noticed. First, you see more brow ridges (a trait of both neanderthals and Homo erectus) on whites. And if you go back far enough, chimpanzee hair is straight and brown, like that of a white person. But, on the other measures I mentioned, it goes the other way.

Yes, prognathism does vary among blacks, just like skull size and other measures, just as there is variance between whites. But there's also an overall difference between the races. And you have to keep in mind, with many of the blacks you see in England or in the US, they often have a significant percentage of white blood.

Of the examples you used of reconstructions you trust, I actually used two of them in the post. (There are a limited number, and I kept coming across the same images when Googling them.) One of them was the Javier Bardem example, and one of them was actually the side view of the one I used for Jimmy Durante. (The girl pretending to kiss that Neanderthal was a real girl photographed at whichever museum he is displayed at.)

It's my guess that if they ever recover a usable sample ofHomo Erectus DNA, which is entirely possible given that he only disappeared 70,000 years ago, they'll find that, as with Neanderthals, some races have more DNA in common with him than others do. (I'm not suggesting that any race is still EXACTLY erectus.)

John Craig said...

Steven --
PS -- My understanding is that the skulls of pure Africans and pure Caucasians are very easy to tell apart.

Steven said...

No doubt different human races have more or less dna contribution from different earlier hominid species.

Do you agree with me that modern Africans have much more similar skulls and are genetically closer to modern Europeans than to their homo ergaster or homo erectus ancestors?

John Craig said...

Mark --
I think what Steven was saying was not all that dissimilar to what you're saying, though you're somewhat at cross purposes: that if you DO have one great great grand parent in your line who was somehow different, that difference will be lost in the mix. For instance, if an American has one great great grand parent who is black, that blackness will no longer be recognizable. (In fact, with many people who are only 1/8th black, it's no longer visible.)

Steven said...


I see the point you are making but I'm not sure you're right there.

All modern humans have 99.9% of dna in common and differ on average at 1 in 1000 places in the genome. So when you say you have 50% of your parents dna, that is 50% of that 0.1% on top of the 99.9% you have in common with all humans.

If modern Europeans have 1-4% neanderthal dna, then it isn't constant for all Europeans in every generation, is it? It must be part of the 0.1% we inherit from our parents...the part that makes humans differ. That's why some humans have neanderthal brow ridges but most don't...they are literally more neanderthal than other humans.

Humans and zebra fish have 85% dna in common, humans and chimps 98% so most of our common dna will be in common with neanderthals, not just 4%.

Steven said...

...actually I made a mistake there...its not part of the 0.1% we inherit from our parents....that's the human part. Humans and neanderthals differ at about 3 places in 1000 in the genome I think, so some Europeans are more neanderthal. Its not constant though because you could have one parents with more neanderthal dna and than the other and it depends what bits of dna you get from each. Whereas, the part we all have in common with neanderthals is constant for all humans.

I think that's right??

John Craig said...

Steven --
You just gave three examples of straight on photographs. You have to have a profile view to be able to tell; and I'm guessing the guy in the second photograph is pretty prognathous.

As far as the answer to your other question, I just don't know. It would depend on which samples you used, and whether you used the most modern Erectus skulls or more primitive ones. From the pictures of both Neanderthals and erectus, it looks as if each was the precursor to each race. But of course artists have a lot of latitude, and who knows how accurate all these reproductions are. Plus it would depend on how long ago the races actually separated. Some say 50,000 years ago, some think it's more like 150,000 years or even 200,000 years ago. And bear in mind, Erectus was around until just 70,000 years ago. One thing I will say, those people who say that the races are different species are wrong, given all races ability to interbred and have viable offspring. I'm proof of that.

Steven said...

I guess the neanderthals and humans weren't a different species either then, given they could interbreed. Its all interesting anyway...I just think all the erectus and ergaster drawings I've seen look very alike Africans facially but their craniums look way different and below the eyes, yes..above the eyes, no.

p.s. I'm obviously not clear on the issue of neanderthal dna and whether its part of/ cuts into the 0.1%...but suffice to say it is not constant, it differs between people, may or may not be inherited from a parent, and is above and beyond the 99+% all humans have in common with neanderthals and so the analogy with African admixture holds.

Anonymous said...

This was awesome!

One note: these all seem to be very masculine features. I don't see myself and my daughters (big eyes, pale skin, small noses) in any of these faces at all. So when did that happen? And why?

- Gardner

John Craig said...

Gardner --
Thank you….For some reason, when you Google-image "Neanderthal" or "Homo erectus" or the various other early hominids, most of the pictures that come up are those of men. There are some women too, but fewer. As far as the neanderthals becoming feminized, that was probably mostly a function of them interbreeding with the Cro Magnons. As to why the Cro Magnons had more feminine features (and contours to their bodies), I don't know, your guess is as good as mine. I'm not even sure where the Cro Magnons came from; nothing in my readings so far has made that clear. I guess they evolved from Homo erectus at some point up in the colder latitudes.

Anonymous said...

Have you always been interested in prehistoric man or is this a recent development? Because of your posts on the subject, it's got me thinking more about the evolution of man.


John Craig said...

Birdie --
I've always been interested in evolution and what it teaches us about human nature. The one course that ever really set me on fire in college was the one I took my senior year on sociobiology. But I never really pursued it after college, this current interest is basically just a temporary kick I'm on. (And I think I'm pretty much blogged out on the subject.)

AIDS-HIV Info Blog said...

I like this post. I do think that comparing skulls with facial skin and muscles and especially with facial hair hides the differences. Look at the chin, cheeks, front teeth and brow ridge on this modern skulls.

Compare each of those with the neanderthal.

While they don't look that different at first, if you look in detail, you could immediately train yourself to pick one from another.

John Craig said...

AIDS-HIV Info Blog --
Thanks. I think that first set of photos is a little misleading in that those skulls are not represented to scale. Generally the Caucasian and Asian skulls tend to be a little bit bigger, but that's not apparent from the photo.

You're right, the Neanderthal skull looks quite different from the modern human's skull, and that's apparent at a glance. I've heard that forensic types can also tell almost immediately which race a skull is from.