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I find it fascinating modern humans are thought to have evolved 300k years ago, but we haven't got any idea what happened before last ice age. I find it hard to

I find it fascinating modern humans are thought to have evolved 300k years ago, but we haven't got any idea what happened before last ice age. I find it hard to believe people would just "stay in Africa" prior to last ice age (120k years ago and before) when the moment climate allowed it (~10k years ago) they spread out all over the planet.

kjkjadksj 3y ago
That narrative is changing. Scientists are starting to think the peopling of the americas happened a lot earlier than we previously to believed. https://www.science.org/doi/10.1126/science.abg7586 https://www.science.org/doi/10.1126/science.abg7586
- idoubtit 3y ago
  What is funny is that there's been a consensus for many years in Europe that Hominids arrived in America at least 30,000 years ago. There were several artefacts that made the hypothesis very plausible. But most North American scientist were vigorously opposed to it, until this recent proof that's harder to deny. By the way, this is unrelated to the GP post which was about hominids walking out of Africa, more than 1M years before entering America.
  - AlotOfReading 3y ago
    Well that's certainly one hell of a claim. It's one I feel like I should know about considering I've worked with European researchers on human presence in the arctic in the LGM, but I've never heard of this "consensus". Can you provide some more info? As an aside, the white sands footprints aren't "proof". They're interesting and highly suggestive, but significant concerns remain about the quality of the dating, let alone transbering crossings in the LGM without implicating things like the sketchy refugia hypothesis. It'll be a few years before all that shakes out and we have anything approaching consensus on the matter.
  - cco 3y ago
    In the early 2000's my anthropology courses at a large US university presented 13kya as basically certain and that maybe up to 27kya but that the evidence was pretty early. Perhaps there was more pushback in archeology?
spaceman_2020 3y ago
A big part of the challenge is that most of the areas that might have been inhabited before the last ice age are now underwater. Really hard for early artefacts to survive being under the ocean for 10k years. Nonetheless, I think its fair to say now that we can at least push back the timeline for early civilized settlements to at least the time of Gobekli Tepe (~10k years).
CorrectHorseBat 3y ago
We know a bit more than that https://en.m.wikipedia.org/wiki/List_of_first_human_settlements https://en.m.wikipedia.org/wiki/List_of_first_human_settleme...
ledgerdev 3y ago
You should check out Randal Carlson on Joe Rogan, and this is a very interesting video on the topic. https://youtu.be/3qXuAzzVOTQ https://youtu.be/3qXuAzzVOTQ
lkrubner 3y ago
At this point the argument isn't that people stayed in Africa, but that everyone outside of Africa died. At this point the 3 oldest fossils we have that look like homo sapiens are all from Morocco or the Levant or Greece, suggesting homo sapiens first evolved near the Mediterranean. But at some time between 50k and 20k years ago, all humans outside of Africa seemed to have died: Neanderthals, Denisovans, and Sapiens, all of them. Regarding the older finds of Sapiens, when we find DNA traces and compare them to modern DNA, we are not able to find any modern population that is descended from any of this Sapien DNA, outside of Africa, that is older than even 25k. It is well known that Sapiens arrived in Spain 40k years ago and that they demonstrated modern behavior: arts, music, advanced hunting tools, but DNA analysis suggests this group disappeared entirely, no trace of their DNA is found in existing European populations. The picture then is that 75k ago Eurasia was covered with humans, of at least 3 or 4 different species, and all of them died, and then Eurasia was repopulated by a burst of homo sapiens that radiated out from Africa. Of course, this picture would change if we ever found some old DNA, outside of Africa, that could also be matched to DNA in a surviving group of humans.
- Ericson2314 3y ago
  Are you saying it is less that homo sapiens out-competed the others than the ice age knocked out everyone? How does that comport with modern humans still having some admixture from them?
  - CogitoCogito 3y ago
    Modern humans having some admixture from them doesn't contradict the idea that the ice age was the bigger problem than direct competition.
  - lkrubner 3y ago
    My own guess would be the final years of the Ice Age saw too many changes in the northern hemisphere, erratic weather that wiped out everyone, but I have not seen that in an official source, except in discussions of Neanderthals. Modern Humans can be an admixture of several species if the ancestors to modern humans either migrated south to Africa or continued to survive in some place like Arabia, but perhaps we just haven't found the right fossil yet. Assuming Sapiens and Neanderthals mixed together in the Levant then they either survived in the Levant or they moved south into Africa and then later expanded out of Africa.
idoubtit 3y ago
As pointed by https://en.wikipedia.org/wiki/Recent_African_origin_of_modern_humans#Proposed_waves https://en.wikipedia.org/wiki/Recent_African_origin_of_moder... it seems that modern humans went of out Africa in many waves at various eras. It's not surprising, the other Homo genus did the same.
xkjyeah 3y ago
The book Pathogenesis published this year has a hypothesis -- diseases from the Neanderthals and other hominids who populated the regions outside Africa earlier wiped out the earlier waves of Sapiens. Until diseases spread back and forth enough that Sapiens had enough immunity to non-Sapien diseases, but not vice versa (due to lower population density or less diverse fauna outside Africa) which wiped out the non-Sapiens populations outside Africa.
philwelch 3y ago
Razib Khan’s Substack has a lot of pieces about the complexities of out-of-Africa; here are a few that aren’t paywalled: https://www.razibkhan.com/p/out-of-africas-midlife-crisis https://www.razibkhan.com/p/out-of-africas-midlife-crisis https://www.razibkhan.com/p/yo-mamas-mamas-mamas-mama-etc https://www.razibkhan.com/p/yo-mamas-mamas-mamas-mama-etc https://www.razibkhan.com/p/current-status-its-complicated https://www.razibkhan.com/p/current-status-its-complicated
opportune 3y ago
After 300k years ago people are called anatomically modern humans, not “final copy” humans. Evolution never stopped. And even if evolution did stop, consider that developing primitive technology, language, and culture (eg wearing of clothes, a notion of “fairness” or “justice” so conflicts can be resolved without killing people) into something that’d allow humans to be as environmentally adaptable as they are today could itself take a long time. Humans didn’t “stay in Africa” and early Homo sapiens certainly didn’t wait until 10k years ago to spread across the planet. Going off memory here but pretty sure the current theory is early Homo sapiens started to spread out of Africa about ~70-60k years ago. 10k years ago is around when agriculture and “civilization” began. Also other hominids, arguably a kind of human, like Neanderthals and homo erectus had left Africa well before 100k years ago - considering they were probably more adapted to their environment in many cases it’s not that far fetched to think their presence generally made it harder for early Homo sapiens to displace them or coexist with them, given they’d occupy similar ecological niches.
edgyquant 3y ago
People definitely didn’t “stay in Africa”[1] we find skulls and the like from ancient humans all over Eurasia basically at every point in time for the last 1-2 million years. Any claim that Homo sapiens didn’t exist outside of Africa is disputed. 1. https://en.m.wikipedia.org/wiki/Petralona_skull https://en.m.wikipedia.org/wiki/Petralona_skull

kjkjadksj 3y ago

That narrative is changing. Scientists are starting to think the peopling of the americas happened a lot earlier than we previously to believed. https://www.science.org/doi/10.1126/science.abg7586 https://www.science.org/doi/10.1126/science.abg7586

idoubtit 3y ago
What is funny is that there's been a consensus for many years in Europe that Hominids arrived in America at least 30,000 years ago. There were several artefacts that made the hypothesis very plausible. But most North American scientist were vigorously opposed to it, until this recent proof that's harder to deny. By the way, this is unrelated to the GP post which was about hominids walking out of Africa, more than 1M years before entering America.
- AlotOfReading 3y ago
  Well that's certainly one hell of a claim. It's one I feel like I should know about considering I've worked with European researchers on human presence in the arctic in the LGM, but I've never heard of this "consensus". Can you provide some more info? As an aside, the white sands footprints aren't "proof". They're interesting and highly suggestive, but significant concerns remain about the quality of the dating, let alone transbering crossings in the LGM without implicating things like the sketchy refugia hypothesis. It'll be a few years before all that shakes out and we have anything approaching consensus on the matter.
- cco 3y ago
  In the early 2000's my anthropology courses at a large US university presented 13kya as basically certain and that maybe up to 27kya but that the evidence was pretty early. Perhaps there was more pushback in archeology?

spaceman_2020 3y ago

A big part of the challenge is that most of the areas that might have been inhabited before the last ice age are now underwater. Really hard for early artefacts to survive being under the ocean for 10k years. Nonetheless, I think its fair to say now that we can at least push back the timeline for early civilized settlements to at least the time of Gobekli Tepe (~10k years).

CorrectHorseBat 3y ago

We know a bit more than that https://en.m.wikipedia.org/wiki/List_of_first_human_settlements https://en.m.wikipedia.org/wiki/List_of_first_human_settleme...

ledgerdev 3y ago

You should check out Randal Carlson on Joe Rogan, and this is a very interesting video on the topic. https://youtu.be/3qXuAzzVOTQ https://youtu.be/3qXuAzzVOTQ

lkrubner 3y ago

At this point the argument isn't that people stayed in Africa, but that everyone outside of Africa died. At this point the 3 oldest fossils we have that look like homo sapiens are all from Morocco or the Levant or Greece, suggesting homo sapiens first evolved near the Mediterranean. But at some time between 50k and 20k years ago, all humans outside of Africa seemed to have died: Neanderthals, Denisovans, and Sapiens, all of them. Regarding the older finds of Sapiens, when we find DNA traces and compare them to modern DNA, we are not able to find any modern population that is descended from any of this Sapien DNA, outside of Africa, that is older than even 25k. It is well known that Sapiens arrived in Spain 40k years ago and that they demonstrated modern behavior: arts, music, advanced hunting tools, but DNA analysis suggests this group disappeared entirely, no trace of their DNA is found in existing European populations. The picture then is that 75k ago Eurasia was covered with humans, of at least 3 or 4 different species, and all of them died, and then Eurasia was repopulated by a burst of homo sapiens that radiated out from Africa. Of course, this picture would change if we ever found some old DNA, outside of Africa, that could also be matched to DNA in a surviving group of humans.

Ericson2314 3y ago
Are you saying it is less that homo sapiens out-competed the others than the ice age knocked out everyone? How does that comport with modern humans still having some admixture from them?
- CogitoCogito 3y ago
  Modern humans having some admixture from them doesn't contradict the idea that the ice age was the bigger problem than direct competition.
- lkrubner 3y ago
  My own guess would be the final years of the Ice Age saw too many changes in the northern hemisphere, erratic weather that wiped out everyone, but I have not seen that in an official source, except in discussions of Neanderthals. Modern Humans can be an admixture of several species if the ancestors to modern humans either migrated south to Africa or continued to survive in some place like Arabia, but perhaps we just haven't found the right fossil yet. Assuming Sapiens and Neanderthals mixed together in the Levant then they either survived in the Levant or they moved south into Africa and then later expanded out of Africa.

idoubtit 3y ago

As pointed by https://en.wikipedia.org/wiki/Recent_African_origin_of_modern_humans#Proposed_waves https://en.wikipedia.org/wiki/Recent_African_origin_of_moder... it seems that modern humans went of out Africa in many waves at various eras. It's not surprising, the other Homo genus did the same.

xkjyeah 3y ago

The book Pathogenesis published this year has a hypothesis -- diseases from the Neanderthals and other hominids who populated the regions outside Africa earlier wiped out the earlier waves of Sapiens. Until diseases spread back and forth enough that Sapiens had enough immunity to non-Sapien diseases, but not vice versa (due to lower population density or less diverse fauna outside Africa) which wiped out the non-Sapiens populations outside Africa.

philwelch 3y ago

Razib Khan’s Substack has a lot of pieces about the complexities of out-of-Africa; here are a few that aren’t paywalled: https://www.razibkhan.com/p/out-of-africas-midlife-crisis https://www.razibkhan.com/p/out-of-africas-midlife-crisis https://www.razibkhan.com/p/yo-mamas-mamas-mamas-mama-etc https://www.razibkhan.com/p/yo-mamas-mamas-mamas-mama-etc https://www.razibkhan.com/p/current-status-its-complicated https://www.razibkhan.com/p/current-status-its-complicated

opportune 3y ago

After 300k years ago people are called anatomically modern humans, not “final copy” humans. Evolution never stopped. And even if evolution did stop, consider that developing primitive technology, language, and culture (eg wearing of clothes, a notion of “fairness” or “justice” so conflicts can be resolved without killing people) into something that’d allow humans to be as environmentally adaptable as they are today could itself take a long time. Humans didn’t “stay in Africa” and early Homo sapiens certainly didn’t wait until 10k years ago to spread across the planet. Going off memory here but pretty sure the current theory is early Homo sapiens started to spread out of Africa about ~70-60k years ago. 10k years ago is around when agriculture and “civilization” began. Also other hominids, arguably a kind of human, like Neanderthals and homo erectus had left Africa well before 100k years ago - considering they were probably more adapted to their environment in many cases it’s not that far fetched to think their presence generally made it harder for early Homo sapiens to displace them or coexist with them, given they’d occupy similar ecological niches.

edgyquant 3y ago

People definitely didn’t “stay in Africa”[1] we find skulls and the like from ancient humans all over Eurasia basically at every point in time for the last 1-2 million years. Any claim that Homo sapiens didn’t exist outside of Africa is disputed. 1. https://en.m.wikipedia.org/wiki/Petralona_skull https://en.m.wikipedia.org/wiki/Petralona_skull