Fossils from Morocco complicate the story of modern humans(nature.com)
nature.com
Fossils from Morocco complicate the story of modern humans
https://www.nature.com/scientificamerican/journal/v317/n3/full/scientificamerican0917-12.html
57 comments
I'm reading the book Sapiens right now, which I highly recommend. Lots of interesting facts. But also a broad explanation of the theory of human development.
Most interesting fact I learned: At one point there were as many as 6 human species (Homo sapiens, homo errectus, etc) on earth at the same time!
Most interesting fact I learned: At one point there were as many as 6 human species (Homo sapiens, homo errectus, etc) on earth at the same time!
I really really recommend the sequel of Sapiens, Homo Deus. I can't really describe it in words.
Very interesting! I'm not sure I agree with your reasoning for the mitochondrial mutation point:
> * Mitochondrial DNA is passed by mothers only and so undergoes very little mutation
The mutation rate of mitochondrial DNA is much faster than in nuclear DNA [1]. But mitochondrial DNA does not have crossover, so the mutation tree is much easier to build.
[1] From: https://en.wikipedia.org/wiki/Mutation_rate#Variation_in_mut...
> Human mitochondrial DNA has been estimated to have mutation rates of ~3× or ~2.7×10−5 per base per 20 year generation (depending on the method of estimation); these rates are considered to be significantly higher than rates of human genomic mutation at ~2.5×10−8 per base per generation. Using data available from whole genome sequencing, the human genome mutation rate is similarly estimated to be ~1.1×10−8 per site per generation.
[1] From: https://en.wikipedia.org/wiki/Mutation_rate#Variation_in_mut...
> Human mitochondrial DNA has been estimated to have mutation rates of ~3× or ~2.7×10−5 per base per 20 year generation (depending on the method of estimation); these rates are considered to be significantly higher than rates of human genomic mutation at ~2.5×10−8 per base per generation. Using data available from whole genome sequencing, the human genome mutation rate is similarly estimated to be ~1.1×10−8 per site per generation.
Saw this after I posted.
I would expect the mutation rates of mitochondrial and nuclear DNA to be about the same, unless the mitochondria have additional repair proteins not involved with nuclear DNA, or the shorter length of the mitochondrial chromosome affects the rates, or some other process I'm not familiar with. I think maybe parent meant to refer to diversity, not mutation. With nuclear DNA, the offspring chromosomes are made up from a combination of the parents' DNA. There's a lot of swapping and mixing and matching that takes place. This adds diversity to the population.
Diversity! Not mutation. Thanks for clearing that up. I'd edit my original comment if I still could.
Wow. That last bullet point is particularly remarkable to me - both the implied level of 'technological understanding' and presumed foreplanning for significant journeys 30K years back and for the capacity of oral history to record what come today might not be the most pertinent information.
Also quite amusing in the context of contemporary Australia's philosophy where alien plants and animals are concerned! :)
Also quite amusing in the context of contemporary Australia's philosophy where alien plants and animals are concerned! :)
Citing that article:
> “It suggests that Aboriginal oral traditions may have endured for up to 30,000 years, and lends further weight to the idea that some Aboriginal myths pertaining to gigantic animals may be authentic records of extinct megafauna”
Wow ^ 2
> “It suggests that Aboriginal oral traditions may have endured for up to 30,000 years, and lends further weight to the idea that some Aboriginal myths pertaining to gigantic animals may be authentic records of extinct megafauna”
Wow ^ 2
I'm always extremely skeptical when someone suggests that oral traditions could possibly have survived for long periods of time. That's twelve hundred generations! Given what we know about the speed at which Chinese Whispers tend to drift, the idea that any story can last 1200 generations is an extraordinary claim that demands extraordinary proof.
Hundreds of Aboriginal tribes had hundreds of contradictory myths on hundreds of subjects. Most of them are verifiably false (e.g. those rocks over there are not, in fact, the remains of three young women who got turned into stone for disobeying their father). Some of them are probably correct by complete accident.
As for gigantic animals... well, they're a pretty common motif in myths and stories all around the world. Maybe it's some distant memory our cultures all have of the larger animals that used to live around here... or maybe it's just because giant animals are cool. In Aboriginal myths, giant animals are often really really giant, because they're used as explanations for geographic features -- e.g. rivers are caused by the meanderings of a giant snake.
Hundreds of Aboriginal tribes had hundreds of contradictory myths on hundreds of subjects. Most of them are verifiably false (e.g. those rocks over there are not, in fact, the remains of three young women who got turned into stone for disobeying their father). Some of them are probably correct by complete accident.
As for gigantic animals... well, they're a pretty common motif in myths and stories all around the world. Maybe it's some distant memory our cultures all have of the larger animals that used to live around here... or maybe it's just because giant animals are cool. In Aboriginal myths, giant animals are often really really giant, because they're used as explanations for geographic features -- e.g. rivers are caused by the meanderings of a giant snake.
I wouldn't take it as 'extremely skeptical', it's fact that this is junk 'science'
We can look at story drift even in non primitive societies where they have writing and it's huge within generations.
We can look at story drift even in non primitive societies where they have writing and it's huge within generations.
Some tribes in north of Australia have verifiable myths about the geography of the lands that have been under the sea off the north of Australia for 6-8 thousand years at least (meaning, the description of the land features matches the sea floor geography).
Has anyone quantified their myths properly? If not then they're just cherry picking.
Do you have any proof that they are just cherry picking?
No, I just assume they are until they provide data to prove otherwise. We don't even know if the same tribes were in the same area that long ago.
On a similar timescale, lots of cultures from the middle east have a flood myth, which is thought to be a real event from about 15k years ago.
I'm sorry, but that statement is very likely incorrect. 15kya was very soon after the last glacial maximum (24-18kya) and sea levels weren't significantly affected by then. The receding of the ice sheets started at cca 18kya, but was going slowly at first and only accelerated after 15kya.
Most of middle east cultures draw the myth from Mesopotamian cultures, whose flood myth most likely refers to the flooding of the Persian gulf (which Eufrat and Tigris drain to currently, but used to be a fertile lowland with multiple rivers) cca 8kya.
https://www.livescience.com/10340-lost-civilization-existed-...
Considering the map in this article, with abundance of rivers across the whole Persian gulf plain, I would suggest that the myth of exile from Eden is also related to it - after the flooding and subsequent move of people upriver between the Eufrat and Tigris there was a need to create irrigation channels to keep the agricultural production up at necessary levels. Creating and maintaining these channels is hard, back-breaking work, and it might have inspired the famous 'By the sweat of your brow you will eat your food' line.
Most of middle east cultures draw the myth from Mesopotamian cultures, whose flood myth most likely refers to the flooding of the Persian gulf (which Eufrat and Tigris drain to currently, but used to be a fertile lowland with multiple rivers) cca 8kya.
https://www.livescience.com/10340-lost-civilization-existed-...
Considering the map in this article, with abundance of rivers across the whole Persian gulf plain, I would suggest that the myth of exile from Eden is also related to it - after the flooding and subsequent move of people upriver between the Eufrat and Tigris there was a need to create irrigation channels to keep the agricultural production up at necessary levels. Creating and maintaining these channels is hard, back-breaking work, and it might have inspired the famous 'By the sweat of your brow you will eat your food' line.
> Most of middle east cultures draw the myth from Mesopotamian cultures, whose flood myth most likely refers to the flooding of the Persian gulf
I thought the GP was actually referring to this event. Do we have a time frame for that which negates that possibility, because otherwise I'm not sure how your evidence refutes rather than corroborates.
I thought the GP was actually referring to this event. Do we have a time frame for that which negates that possibility, because otherwise I'm not sure how your evidence refutes rather than corroborates.
I thought they were referring to the black sea deluge (https://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis). Some quick googling didn't reveal much, do we know when the persian gulf flooded?
No, I was not referring to the Black Sea deluge. That one is responsible for flood myths in Indo-European cultures (and also for the spread of the Indo-European cultures themselves), and it is more recent (6.5kya if I'm not mistaken).
The article I linked clearly states that it was a fertile land basin until 8kya. I decided to ignore kbenson's lack of reading comprehension hiding behind an attempt to insert himself as an arbiter through nitpicking about a thing he obviously knows nothing about, but I see he's not the only one refusing to read the article, so I'll restate my point:
My point of contention is the 15kya date. By 15kya the receding of ice age ice caps has barely started, so 15kya the ocean levels were not affected in any major way. The major geography-changing ocean level rise came a few thousand years later.
The linked article clearly states the following: "Then, about 8,000 years ago, the land would have been swallowed up by the Indian Ocean, the review scientist said." and "The Gulf Oasis would have been a shallow inland basin exposed from about 75,000 years ago until 8,000 years ago, forming the southern tip of the Fertile Crescent, according to historical sea-level records."
The article I linked clearly states that it was a fertile land basin until 8kya. I decided to ignore kbenson's lack of reading comprehension hiding behind an attempt to insert himself as an arbiter through nitpicking about a thing he obviously knows nothing about, but I see he's not the only one refusing to read the article, so I'll restate my point:
My point of contention is the 15kya date. By 15kya the receding of ice age ice caps has barely started, so 15kya the ocean levels were not affected in any major way. The major geography-changing ocean level rise came a few thousand years later.
The linked article clearly states the following: "Then, about 8,000 years ago, the land would have been swallowed up by the Indian Ocean, the review scientist said." and "The Gulf Oasis would have been a shallow inland basin exposed from about 75,000 years ago until 8,000 years ago, forming the southern tip of the Fertile Crescent, according to historical sea-level records."
> I decided to ignore kbenson's lack of reading comprehension hiding behind an attempt to insert himself as an arbiter through nitpicking about a thing he obviously knows nothing about
While I see how it's possible you could interpret me as trying to insert myself as and arbiter instead of expressing my own lack of knowledge and asking for clarification, it was fully your own choice to not only decide that was the interpretation you believed as fact, but to then broadcast that negative interpretation as fact to others. A little assumption of good faith goes a long way, and I don't think it's too much to ask for.
While I see how it's possible you could interpret me as trying to insert myself as and arbiter instead of expressing my own lack of knowledge and asking for clarification, it was fully your own choice to not only decide that was the interpretation you believed as fact, but to then broadcast that negative interpretation as fact to others. A little assumption of good faith goes a long way, and I don't think it's too much to ask for.
You literally didn't read a very short article I linked in the comment you objected to; in that article the date of cca 8kya is mentioned at least twice very clearly.
But like I said, that's ok.
But like I said, that's ok.
That's ok.
Maybe their digestive tract had carried the seeds ...
Do you happen to have a good source handy on the growing acceptance of the Multi-Regional theory vs the Out of Africa theory? This is obviously a topic with political implications so looking for something that is accepted as a neutral source.
It is not a case of one or the other, they are both right. All non-Africans are a hybrid between Africans and Neanderthals or Africans/Neanderthals/Denisovans.
You are right that this topic is politically sensitive - so sensitive that the data is basically ignored outside of science.
You are right that this topic is politically sensitive - so sensitive that the data is basically ignored outside of science.
Why is it politically sensitive? I can't see any obvious political implications ...
I'm not an expert, so just guessing, but I imagine it's something similar to the whole Arian stuff from the Nazis, ie: "look, our genes are more closely related to the most 'original' and 'pure' human lineage".
A lot of the Multi-regional stuff I learnt is from the University of California Youtube channel. There's a playlist here, it's quite big, but a lot of relevant videos are in there: https://www.youtube.com/watch?v=v0j77rODO3E&list=PL1B24EADC0...
> We certainly bred with Neanderthals and Denisovans
Another way of looking at it is that we are the Neanderthals and Denisovans.
The Neanderthals population is estimated at 70,000 at their peak. At 2% of 7 billion, we Neanderthals are now two thousand times more plentiful!
Another way of looking at it is that we are the Neanderthals and Denisovans.
The Neanderthals population is estimated at 70,000 at their peak. At 2% of 7 billion, we Neanderthals are now two thousand times more plentiful!
You missed what is probably the most important thing about human evolution and that is due to the rapid population rise after the invention of argriculture more human evolution has happened in the last 10,000 years than the previous million.
The other is that human population is filled with new genes that are under positive selection which have only partially spread through the population. Humans are probably the worst species to study genetically as all the normal assumptions you need to make don't hold.
One minor nitpick, your evidence of the oldest oral tradition is not very strong as there are only four major points on the compass. The likelihood of chance and cherry-picking is high.
The other is that human population is filled with new genes that are under positive selection which have only partially spread through the population. Humans are probably the worst species to study genetically as all the normal assumptions you need to make don't hold.
One minor nitpick, your evidence of the oldest oral tradition is not very strong as there are only four major points on the compass. The likelihood of chance and cherry-picking is high.
> your evidence of the oldest oral tradition is not very strong as there are only four major points on the compass. The likelihood of chance and cherry-picking is high.
I think the point is that the palms are introduced (not native) more than their cardinal direction (i dont believe they were using a western compass at the time so as to have four directions)
I think the point is that the palms are introduced (not native) more than their cardinal direction (i dont believe they were using a western compass at the time so as to have four directions)
If you read the articles linked the evidence that this "knowledge" has been passed down for 30,000 years is not strong. Firstly, the palms are native to Australia, just other populations are found 1000 km to the north. Secondly, the palms have only being separated for 15,000 years at most. Thirdly, the northern evidence is actually "gods brought the palms from the north".
The San people of southern Africa are claimed to be the living human group with the most ancient divergence from the rest of humanity, around 200,000 years ago. That they are so similar to the rest of humanity has always made me wonder if the commonly accepted divergence date ranges should be pushed back.
From the Wiki:
"A DNA study of fully sequenced genomes, published in September 2016, showed that the ancestors of today's San hunter-gatherers began to diverge from other human populations in Africa about 200,000 years ago and were fully isolated by 100,000 years ago, well before the first archaeological evidence of modern behaviour in humans."
https://en.wikipedia.org/wiki/San_people?wprov=sfla1
From the Wiki:
"A DNA study of fully sequenced genomes, published in September 2016, showed that the ancestors of today's San hunter-gatherers began to diverge from other human populations in Africa about 200,000 years ago and were fully isolated by 100,000 years ago, well before the first archaeological evidence of modern behaviour in humans."
https://en.wikipedia.org/wiki/San_people?wprov=sfla1
I guess evolutionary change is gradual so it's hard to have a cut off date for when pre homo sapien ancestors had kids that counted as homo sapiens. The origins of cooking going back 1.9 million years implies the ancestors must have been a bit human like. https://www.theguardian.com/science/2011/aug/22/cooking-orig...
Evolution is not single speed. For a relatively static population with no need to change their lifestyle it will run more slowly. For a dynamic population with bottlenecks it can run very quickly.
Not only that, their divergence date (cca 175kya-200kya), combined with the fact that they have language, culture and art disproves the 'behavioral modernity' theory which posits that human brains evolved to use language and produce culture and art relatively recently (30kya) based on the oldest currently available archeological finds of expressions of culture/art.
Do you know if they are related to the Berbers?
Well, we are all related to each other, the only question is how _closely_ related we are. And as for that, any non-Khoisan/non-Pygmy human subgroup is more closely related to any other non-Khoisan/non-Pygmy subgroup than they are to Khoisan or Pygmy people. In other words, Khoisan and Pygmyies are the most distant cousins to all other homo sapiens (diverged from us 175-200 thousand years ago).
Seems rather unlikely, given their appearance.
I was always surprised by the tendency of anthropologists to assign hard evolutionary 'milepoints' based on the very limited set of archeological data. Most egregious example is 'behavioral modernity' theory which claims that homo sapiens developed language, culture and art only relatively recently (30kya) because that's how old the currently oldest archeological finds of culture/art expression are. This doesn't stand up even to the simplest application of Occam's razor.
But then the question is why our ancestors didn't invent stuff 100 thousand years earlier.
Well, that's not what I'm arguing. What I am arguing is that lack of proof is not proof of lack - the fact that, for example, currently oldest artwork we know of is 30 000 years old does not prove that's when homo sapiens started making art and not any earlier, but instead that it proves that humans have been making art AT LEAST 30kya, AND that they must have started doing it earlier.
P.S. the 'oldest art is 30 thousand years old' bit is in the context of 'behavioral modernity' theory at the time it was posited, based on European cave art; in the meantime, we've found even older art in a cave in Indonesia (40 thousand years old).
P.S. the 'oldest art is 30 thousand years old' bit is in the context of 'behavioral modernity' theory at the time it was posited, based on European cave art; in the meantime, we've found even older art in a cave in Indonesia (40 thousand years old).
I've never really grasped where the surprise comes from with these kinds of discoveries - we know that our ancestry always had the potential to give rise to lines that look very much like us, since we look very much like us. Why should it be a surprise if it happened more than once? We're looking at a terribly long timescale, after all - at least by comparison to our recorded history.
Evolution is not linear. At each step there are multiple choices. If you split a population, each one will have different problems in it's environment to solve or they may "find" different solutions to the same problems.
After some time the changes in the ADN make the two population incompatible for reproduction, so they become different species. [An easy case is when the number of chromosomes changes in one of the part but it doesn't change in the others. But more subtle changes are more frequent.]
After some time the changes in the ADN make the two population incompatible for reproduction, so they become different species. [An easy case is when the number of chromosomes changes in one of the part but it doesn't change in the others. But more subtle changes are more frequent.]
> After some time the changes in the ADN make the two population incompatible for reproduction, so they become different species.
The time scales being discussed here are orders of magnitude too short to even consider speciation, evidenced by what we know about our human/Neanderthal hybrid ancestors, and the fact that a Pygmy or Khoi-San person can have viable offspring with any person of the opposite gender in the human diaspora today.
The time scales being discussed here are orders of magnitude too short to even consider speciation, evidenced by what we know about our human/Neanderthal hybrid ancestors, and the fact that a Pygmy or Khoi-San person can have viable offspring with any person of the opposite gender in the human diaspora today.
I think how you attribute the surprise matters. The order of discoveries brought forth a conventional story that stood for a seemingly long time. Now that story may need to be re-examined.
There is a difference between the discovery & subsequent scientific reports and the story drawn from them. The story is less accurate, tends to be more romantic and gets the widest exposure. Even the scientists subscribe to one version or another because they are human. The likely change in the common story is the source of the surprise and excitement.
This process guarantees that there will always be a surprise, and roughly speaking it will be directly proportional to how long the story has been in place and inversely proportional to the number of such competing stories.
There is a difference between the discovery & subsequent scientific reports and the story drawn from them. The story is less accurate, tends to be more romantic and gets the widest exposure. Even the scientists subscribe to one version or another because they are human. The likely change in the common story is the source of the surprise and excitement.
This process guarantees that there will always be a surprise, and roughly speaking it will be directly proportional to how long the story has been in place and inversely proportional to the number of such competing stories.
I'm surprised how much variations there are in the dating of the fossils. At first it's 40'000 years, then 160'000, then between 280'000 and 350'000.
Can someone explain to me why there's so much difference?
Can someone explain to me why there's so much difference?
I wish they'd go into more detail about how the shape of the brain case affects brain organization. Does anyone have a good layman-oriented source on that?
Edit: it looks like both are affected by differences in brain development. https://www.mpg.de/623578/pressRelease201011021
Edit: it looks like both are affected by differences in brain development. https://www.mpg.de/623578/pressRelease201011021
It doesn't seem like there's anything new in this article compared to the original announcement.
* In the last few years the Out Of Africa theory (modern humans originated solely in Africa) has received stiff competition from the Multi Regional theory. Namely that waves of human species have left Africa since we diverged from chimpanzees 4 million years ago and that our ancestors are from all the homo-inhabited regions of the world to a greater or lesser extent.
* Neanderthals and Denisovans are 2 known species that certainly inhabited much of the world (apart from the Americas) from around 2/300,000 to 50,000 years ago.
* We certainly bred with Neanderthals and Denisovans, some of us contain up to 4% of their DNA.
* Mammals generally take about 5 million years before they evolve far enough to be reproductively isolated. Of course before then there can still be breeding problems, for which there is evidence of in our breeding with the aforementioned.
* DNA from human skeletons several hunreds of thousands of years old can still be analysed.
* Mitochondrial DNA is passed by mothers only and so undergoes very little mutation. So it provides a stable and valuable signature for detecting ancient affinities between species/sub-species.
* By analysing the variation within genes certain characteristics can be interpreted like population size (eg; there were very few Denisovans) and that there are as yet unidentified species that humans have inherited from.
* Neanderthals possessed the FOXP2 gene known to be central in human speech.
* One of the oldest known oral traditions has evidence to verify a story from around 30,000 years ago: that Australian aboriginees brought the palm tree seeds with them from the north. See: http://www.abc.net.au/news/2015-04-03/aboriginal-legend-palm...
Forgive any errors in this amateur homework report.