There are some good arguments that make me a little skeptical towards the Out of Africa theory. What is the Out of Africa theory?
The general idea is that Homo sapiens came out of East Africa and moved into the Middle East. After this they continued to expand, spreading first into India and Asia and Australia, before spreading up into Europe. After moving from Asia into Russia they were then able to reach North America and eventually travelled down into South America.
That map is slightly misleading even though it is from the Wikipedia page, the official theory is that modern humans left Africa about 65kya (thousand years ago), not 100kya. Wikipedia says:
Note the sentence about modern humans in China, we will come back to that. Anyway here are the arguments.
1. Replacing native populations is hard
Usually natives know the land better, and defend it desperately. Invaders typically need far greater numbers, or much better technology.
Not only is invasion difficult, but Europe and Russia are exceptionally difficult because these places are very cold. This would explain why they reached Australia before Europe, so at least that part of the theory is logical.
The north was not just cold, but the last ice age occurred from around 100kya to 12kya. There were many fluctuations in levels of glaciation at this time, but we know that the last glacial maximum was around 22kya. Modern humans (Homo sapiens) did not pick a good time to break out of Africa, and certainly not a good time to advance anywhere into Russia.
Neanderthals (Europe) and Homo erectus (Asia) had tools and weaponry going back hundreds of thousands of years:
Hunting spears found in Germany and England - 400kya
Hearths found in Israel, France, England, China - 200k to 800kya
Stone axes found in Spain- 900kya1
Wolves were likely domesticated in North Eurasia over 100kya2
Homo floresiensis used rafts to reach an Indonesian island - 900kya3
The oldest stone tools on Flores island are over 1 million years old. Considering their small brain, some researchers theorize that Homo floresiensis inherited their tools from Homo erectus. In other words, Homo erectus may have used primitive boats 900k years ago. In contrast, no islands off the coast of Africa were ever colonised before modern times, despite the fact they can be seen from the mainland. In fact, Homo sapiens first arrived in Madagascar about 10kya, not from Africa, but from Indonesia.
Not only did populations outside Africa have equally advanced, or even more advanced cultures, they also had physical adaptations to the cold that would make replacement extremely difficult. The invaders would have had a difficult time obtaining food and staying alive in the new environment, let alone warring with the natives.
2. Inconsistent evolution
Africans are the most isolated race, genetically speaking. Every single race of people are closer to each other than they are to Africans. Europeans are closer to Australian Aborigines, Eskimos, Indians and Japanese than they are to Africans. The Chinese are genetically closer to South Americans and Saudi Arabians than they are to Africans.
How can we explain this genetic gap? Man supposedly became modern inside Africa, and then when some of these modern humans left Africa, the ones remaining must have stopped evolving completely.
You might say that the Africans actually continued evolving but just in a different direction. This cannot be true, because Africans are genetically the closest race to chimpanzees, by far. So why did African erectus evolve into modern Africans, and then suddenly stop evolving?
3. Evidence for migration INTO Africa
Generally migratory patterns go like this:
Populations in colder climates undergo harsher selection criteria (more population bottlenecks), and usually evolve for greater intelligence
These populations become more cohesive (better social skills) and have better technology
These populations run out of room (either due to glaciation or too many people/not enough food) and expand into warmer climates, using their superior culture to replace the native population
African populations have greater genetic variation. The claim is that this is because they are an older population. If they are older, they must have been the founder population, or so the logic goes. However, another reason could be that Africans experienced several waves of migrations from populations outside Africa, who entered Africa and interbred or replaced them.
A study found that “African populations are shown to experience low levels of mitochondrial DNA gene flow, but high levels of Y chromosome gene flow.”4 This could be due to high levels of inter-African population replacement by males, or due to males entering Africa from the Arabian peninsula.
Another study found Neanderthal DNA in Africans:
For 10 years, geneticists have told the story of how Neanderthals—or at least their DNA sequences—live on in today's Europeans, Asians, and their descendants. Not so in Africans, the story goes, because modern humans and our extinct cousins interbred only outside of Africa. A new study overturns that notion, revealing an unexpectedly large amount of Neanderthal ancestry in modern populations across Africa. It suggests much of that DNA came from Europeans migrating back into Africa over the past 20,000 years. … The researchers found that African individuals on average had significantly more Neanderthal DNA than previously thought—about 0.3% of their genome.5
Furthermore, all archaeological findings of modern man (skulls etc) in Africa are found in East Africa, close to the Arabian peninsula. Therefore, the findings of all these modern skulls could be due to:
Populations entering INTO Africa
The large amount of volcanoes in the East African rift, since volcanic ash helps preserve artefacts
5. Asian erectus
This picture shows a skull found in Liujiang County, China. It is unequivocally modern. The top of the skull is smooth and evenly domed and shows not even a hint of a thickening or a saggital keel. There are no brow ridges and the face is refined with small teeth. The Liujiang skull was initially dated at 87kya but it was found in sediment dated at 110kya to 138kya and some experts believe it is over 150kya. Its skull capacity is a remarkable 1480cc, higher than today’s Caucasians (1441 cc), much higher than today’s Africans (1338 cc), and only slightly less than today’s Asians (1491 cc).6 The Liujiang skull proves that modern man was in China long before modern humans supposedly left Africa (65kya).
Another fact about the Chinese skull that is not as easily seen, is that the Chinese skulls have “shoveled” incisors. Shoveled incisors are seen only rarely in living Caucasians and almost never in living Africans (except for Bushmen), but they are common in living Asians and Native Americans that came from Asia. But where did the Asians get them from? All of the Chinese fossils (that have incisors) have shoveled incisors, dating back to the earliest Asian Homo erectus (Java Man) about 1.8 mya. Hmmm.
Now if the Chinese Homo erectus had shoveled incisors, Peking Man, Dali, Jinniushan, and Liujiang had shoveled incisors, and many of the Chinese alive today have shoveled incisors, and a significant percentage of no other living population outside of Asia commonly has them, it doesn’t take a Sherlock Holmes to figure out what’s going on here. Modern Chinese evolved from an Asian erectus, long before “modern man” ever left Africa.
In addition to shoveled incisors, all Chinese skulls from erectus to the present show a remarkable similarity in head shape and facial characteristics, as well as a gradual change in features. The table below summarizes the skulls presented in this chapter; Java Man is from Indonesia, but hominin fossils of about the same date have been found in China.
6. Orangutans vs Chimpanzees
Humans are genetically closer to chimps than orangutans. Since chimps live in Africa and orangutans live in Asia, this supports the OoA theory. However, this could be due to archaic humans breeding back into the chimp line, not necessarily because we are descended from chimps.
In fact, there are many fascinating similarities between humans and orangutans (and bonobos) that makes our genetic proximity to chimps seem less significant:
Orangutans walk on their palms, as they have not evolved specific traits for knuckle-walking (like being able to lick the wrist). Humans also do not possess these traits while Chimpanzees do.
Chimps don’t walk bipedally, but bonobos and orangutans do occasionally. The orangutan is the only ape with a knee joint similar to that of humans.
Unlike common chimps, female bonobos have more prominent breasts and are sexually receptive throughout most of their estrus cycle.
Nipples in humans are farther apart than in African apes, and even farther apart in orangutans.
Only humans and orangutans, of all the great apes (including even the gibbon), have a thick layer of enamel on the teeth.
Female chimp genitals swell during ovulation, signaling to males that she is ready to copulate, which does not occur in humans and orangutans.
Orangutans display more K-selected traits than chimps, such as copulation outside the ovulation period, greater female-driven mate selection, stronger mother-infant bonds, longer life expectancy, less polygamy and slower maturation rates.
Orangutans and humans lack brow ridges.
Orangutans and humans have long hair and some orangutans grow long beards and have a receding hairline.
Next to humans, orangutans have the greatest amount of left-right asymmetry in their brains, which is related to the acquisition of language and handedness (orangutans are predominately right handed; chimps use either hand).
Orangutans have culture, use human tools, copy human behavior, and have a mechanical ability that anticipates humans. They are the Houdinis of the primate world, able to escape cages by tinkering with their locks. Unlike chimpanzees, orangutans construct shelters with roofs and sometimes even sides. They whistle and attempt to imitate human speech.
During pregnancy, both orangutans and humans excrete 4 or 5 times more estriol than the African apes; estriol may spur fetal brain growth.
Orangutans are more altruistic, more expressive, and more intelligent, although it was long-believed that chimps were the smartest ape.
Only humans and orangutans smile with a closed mouth.
Conclusion
There are other arguments that can be made, like how there was nowhere near enough time for all the races to evolve their specific traits that we see today.78 However, these arguments require in-depth knowledge of genetic science and archaeology, which I do not have, and I’m not sure its necessary.
Most information in this article was taken from one of my all-time favourite books. It has the humorously provocative title Erectus Walks Amongst Us, with an equally provocative cover picture. The book is extremely well researched. I strait up just copied some paragraphs, but took out all the citations because I cannot be bothered putting all the references in. The book has over 900 references, although it is from 2008 so some of the studies are a little dated for genetic science. A pdf link is here.
I don’t really know or care if OoA is wrong, although I suspect it is. It doesn’t make much difference to any research about race differences. Another theory is that man evolved in Eurasia, and repeatedly entered into Africa and interbred with apes and archaic humans.
Something like this. I forgot about Neanderthals but you get the general idea.
https://www.sciencenews.org/article/europes-oldest-stone-hand-axes-emerge-spain
Wayne's research, which is based on complete nuclear DNA (rather than segments of only mtDNA), shows that dogs are over 100,000 years old. The oldest known remains of a dog, however, date to only about 14,000 ya in Russia, with another 14,000 ya find in Germany, where a dog was buried with two people. The bones of wolves have been found with hominoid bones in China, dated 500,000 ya. The cat started living with humans as early as 130,000 ya in the Middle East, protecting stores of grain from rodents.
Wayne, R.K. (June, 1993). Molecular evolution of the dog family. Trends in Genetics, 9(6):218-224.
https://archive.archaeology.org/9805/newsbriefs/mariners.html
Garrigan, D., Kingan, S. B., Pilkington, M. M., Wilder, J. A., Cox, M. P., Soodyall, H., Strassmann, B., Destro-Bisol, G., de Knijff, P., Novelletto, A., Friedlaender, J., & Hammer, M. F. (2007). Inferring human population sizes, divergence times and rates of gene flow from mitochondrial, X and Y chromosome resequencing data. Genetics, 177(4), 2195–2207. https://doi.org/10.1534/genetics.107.077495
https://www.science.org/content/article/africans-carry-surprising-amount-neanderthal-dna
I am pretty sure that these average cranial capacity numbers are slightly wrong. It is hard to find racial brain size studies because it is so taboo now, but older studies were reliable enough. Whites actually have larger brains than Asians, but all the studies automatically adjusted cranial capacity according to body size by default, so the Asians then had larger numbers, because they have significantly smaller bodies than Europeans, and only slightly smaller brains. As for the cranial capacity for the archaic humans, I suppose they are unadjusted.
Eswaran V, Harpending H, Rogers AR. Genomics refutes an exclusively African origin of humans. J Hum Evol. 2005 Jul;49(1):1-18. doi: 10.1016/j.jhevol.2005.02.006. PMID: 15878780.
Harding, R. M., Healy, E., Ray, A. J., Ellis, N. S., Flanagan, N., Todd, C., Dixon, C., Sajantila, A., Jackson, I. J., Birch-Machin, M. A., & Rees, J. L. (2000). Evidence for variable selective pressures at MC1R. American journal of human genetics, 66(4), 1351–1361. https://doi.org/10.1086/302863
"Africans are genetically the closest race to chimpanzees, by far"
I have never heard anyone saying that before and it sounds... implausible. What is your source?
Another fascinating and original story Windsor, on an otherwise taboo subject. So if I understand correctly there could be another "missing link" Asian archaic, or Erectus, ape (maybe related to the Orangutan, or maybe other ape species) we have yet to discover as direct common ancestor? Also, can you point me to other resources to understand these theories better (apart from your generous list of references) -- or is it the case the book you recommend, and references within, are only what's available in the public literature today on this theory?