When did our ancestors split into races?

Firstly, I would like to apologise for my ignorance on this subject. I am going to display my astounding lack of knowledge in this thread, but hey, I have to learn somehow!

I’m curious. As I understand it, the modern census is that humans, or at least our ancestors, originally came from Africa, and migrated from there into the rest of the world. Now as we all know, humans have at some point evolved to match their environments, this being displayed with the slight differences between the human races. For example, people with roots in hotter countries tend to have darker skin as protection against the sun.

What I want to know is…

  1. At what stage did we first split (or evolve to our environment) into the different races? Presumably we were all the same at one point since we all came from the same place? I’m interested in rough dates or eras here.

  2. How recognisable would our ancestors have been as humans today at that time? Were we at modern human stage before the migration from Africa or after? If we were at modern human stage, what race characteristics would we likely all have shown? Dark skin if Africa had a similar climate to today? If, as I suspect, the migration was before humans in the modern sense evolved, what stage were we at? I read that anatomically modern humans evolved around 90,000 years ago (although I also read some people believe as early as 200,000 years ago). So did we split as races after this, or did the races reach the anatomically modern human level independently of each other?

I realise people’s opinions may vary on these matters (squabbling between scientists, not to mention science verses religion), so I would really just like the most popular scientific view.

Thanks in advance for any answers!

It’s important to point out right away that the human race never did “split” into races.

The “races” aren’t biologically distinct from each other. There is typically more genetic and physical diversity (genotypic and phenotypic diversity) within the “races” than between them.

So really, the underlying assumption on which you frame your question is wrong from the start.

Well okay, that’s a fair point but I didn’t want to confuse things by getting pedantic so I used the common “day to day” wording.

I realise we are all very much the same and I’m not really interested in the specific minor differences, I’m just trying to understand our history and when/how we evolved little quirks to match our environments.

Since we are all the same it would suggest that we had fully evolved to modern humans before the migration and the resulting minor differences, but surely Africa wasn’t the only populated place just 90,000 years ago? Does this mean the rest of the world was empty of humans before this, or perhaps populated with an early, now extinct hominid?

I’m just a bit confused with it all.

Biologically, humans inhabiting the world today have so much more in common with each other that the minor differences in appearance that we call race are all irrelevant in any day-to-day context. At least that is how it should be.

However, the small differences in peoples from different parts of the world are of interest because it seems to be a source of information about early human pre-history. DNA evidence suggests that we all have a common ancestry from a small group of humans who existed some 100,000 years ago or so. It seems reasonable to assume that the differences between peoples of the world today must have developed only in the intervening time.

From my understanding, it seems that humans have primarily evolved in Africa and have spread from that continent out into the rest of the world in a series of waves. The extent to which each successive wave displaced or interbred with earlier African emigrants is a controvercial subject which further DNA studies may yet be able to answer.

It seems to me that the physical characteristics of a people in any particular part of the world (outside of africa itself) have been determined by which wave of emigrants happen to settle that place plus a few minor evolutionary adaptations to local conditions that would have had time to evolve - changes to skin pigmentation for example.

I think the question is something like “when did the set of genes that suppresses melanin production change to allow people with white skin to be born.” Or “when did the genes for fat in the eye skin folds first mutate?”

I dunno the answers, though.

Ah, thanks, G. Cornelius, that makes a lot more sense to me now. I hadn’t thought of multiple waves of migration. That fits into what I have previously read much better. It had looked like the dates I read were contradicting each other before!

Thanks again! :slight_smile:

Oh, just saw Biggirl’s post…

Yep, in my ignorance I had kind of asked two questions without even realising it! I think I understand the timeline and how people evolved a bit more after G. Cornelius’ kind post, but a rough date for when people recognisable as today’s “races” came about would be interesting.


There is some evidence that the white skinned peoples of northern Europe are quite recent by anthropological standards, having evolved probably not much more than 5000 years ago.

The chain of reasoning is spelled out in The Sacred Cow and the Abominable Pig: Riddles of Food and Culture by Marvin Harris (originally published as Good to Eat).

In very shortened form, the farmers who moved to northern Europe several thousand years ago (pushing north out of the Middle East) had a difficult time getting enough calcium in their diets. Dairy products were a prime source of calcium. But to digest calcium efficiently you need at least one of two things, preferably both: vitamin D and lactase. The vitamin D can be gotten by exposing skin to sunlight. Too much melanin filters out the sun so whiter skin was preferably selected. (This did not happen elsewhere because the incidence of skin cancer remained too high.) The same with lactase, the enzyme that digests lactose, the sugar in milk. People with the mutant gene that allowed them to digest lactose as adults had a selective advantage over those who did not. Therefore northern Europeans eventually became white-skinned milk drinkers. We think that is normal because that is where American culture predominantly comes from, but it is an anomaly elsewhere in the world.

Exapno, I hadn’t heard that one before.

If it were the case, then why would there be “white” (Caucasian-type) peoples originating from areas where they did NOT raise or herd cattle? I am thinking of the ancient peoples of the horse cultures of Southern Russia; some of their preserved artifacts (and even bodies) show them to be a “European” as any modern European, yet there is no evidence at all to suggest they were cattle herders. I would think there are other examples as well.

And then, if light skin = milk drinkers, why would there be dark pigmented people in east Africa who have been herding and drining milk for millenia? Or Asians, who aren’t dark and don’t drink milk?

And could only 5000 years select out all the African (or at least non-modern-Eurpoean) features of a population, particularly given the fact that the human population of the world was quite small until the last few centuries?

Sorry, I have to be skeptical on Marvin Harris’ claims.

FWIW, Discovery or TLC did a bit on the origins of the various human population groups recently.


The system just ate a long post of mine, brilliantly refuting post point by point because it said I wasn’t logged in. How could I be logged in on every other thread except this one? Mods, what gives?

All right. I will pull my shattered nerves together and try again.

My argument is a specific one, using specific circumstances on a specific population. I do not say that milk drinking = white skins, but that white skins and milk drinking evolved symbiotically in these circumstances. That outcome will not develop in places where these circumstances do not apply.

First, milk does not have to come from cattle, and historically seldom did. Goats, sheep, mares, yaks, camels, and many other animals were used for dairying. There are even distinct names for the otherwise identical fermented milks made from different animals’ milks. The horse cultures made extensive use of mare’s milk. The Mongols even developed the first dried milk, which powder could be carried with them and later reconstituted with water into a thin milk.

Several lines of evidence, including the spread of the Indo-European languages, appear to show that the farmers who moved north and then west across Europe (and also west and then north, i.e. through Greece, Rome and Spain), stem from areas near the Caucasus region. They are ancestral, but the peoples there today do not have the same level of lactose tolerance or whiteness of skin tone as say the Scandinavians. Whiteness is a continuum, not a state of being. But of course they were European. White skins change nothing about that.

The several tribes along the fringes of the Sahara and the Sahal are also a fascinating case of peoples who became milk drinkers through selection pressures. They were herders in areas in which hardly any other food source exists. Naturally those who could drink milk as adults had an advantage. But they lived near the equator and spent their lives outdoors. Why would they need to select for lightness of skin when they got all the vitamin D they needed by exposing their skin to the sun.

Asians are too large a category to pigeonhole. The Chinese, in dense populations, choose the pig rather than grazing animals as their primary meat source. Pigs are not milkable. The Chinese had to get their calcium from other sources, soybeans, e.g. Those farther west did have cattle and better tolerated milk. Indians had cattle and did indeed use their milk. Yogurt and cheese are common items in the Northern Indian cooking, areas which also were influenced by Indo-European speaking peoples. Southern Indians had different food sources and did not need the extra nutrients they could get from milk.

There is no need at all to posit that 5000 years separates Northern Europeans from Africans. As I said, they are descended from peoples elsewhere who had many more thousands of years of separation from African populations. Interestingly, present day Semitic populations have lactose tolerance levels halfway between northern Europeans and eastern Asians.

I admitted that I shortened a complex set of arguments, but there are answers for all the other groups you mention. They just have nothing to do with the particulars of the one case. Harris (who died earlier this year) was probably the foremost anthropological authority on the effect that food had on culture. He also wrote a great many books for the popular audience, some of which cover the other areas I’ve gone into here. In addition to the one mentioned above, an interesting source is the chapter “The Origin of the Sacred Cow” in Cannibals and Kings. There are other writers on the subject as well, although you need to do some digging into the anthro literature to find them.

Minor quibble: skin cancer is probably not the reason, or at least not the primary reason, why people in more tropical regions tended to have evolutionary pressure towards darker skin. Far more likely is that excessive UV penetrating the skin will break down folic acid, which can cause anemia as well as increasing the risk of birth defects in pregnant women.

That’s an interesting conjecture. Harris’ argument refers to skin cancer and I was citing his theories. Do you have a cite for more information for future research?

Most of the features we think of as differing among “races” have no obvious evolutionary advantage (IIRC the technical jargon is “maladaptive”). So sexual selection probably played a major role in producing groups with particular color/size/shape body parts.

Don’t forget also that some non-visible ethnic differences have evolutionary origins. The blood condition that makes people of African and Indian origin prone to sickle cell disease is linked to a desirable inherited system providing protection against malaria.

Good article on the role of vitamins and skin color …