South Asia In Human Evolution (India, Pakistan, Bangladesh, Sri Lanka, Nepal)

South Asia In Human Evolution (India, Pakistan, Bangladesh, Sri Lanka, Nepal)

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Sponsored by nordvpn Let's take a look at a map of some key Asian  archaeological sites that are between 100 and   200,000 years old, roughly. A time period  called the middle to late pleistocene. A   cold time in the earth's climate.  A period of frequent glaciations,   woolly mammoths, the whole  shebang. It's the Ice Age. Over in modern Israel and Palestine you have  Skhul and Qafzeh caves. Humming with the activity   of homo sapiens. Groups like these were probably  hunting and fishing along the shores of an ancient  

lake, now the Nefud desert in Saudi Arabia.  Leaving behind nothing but their footprints. North and east in modern Iraq and Iran  neanderthals are making their home in   Shanidar cave and the Zagros Mountains. Hunting  wild goats, which can't have been easy, for sure.   Further east in the mountains of Uzbekistan,   Teshik Tash cave became the final resting  place of this young Neanderthal child. To the north of here neanderthals and  denisovans occupied Denisova cave,   sometimes on their own sometimes  together evolutionary cousins   raising hybrid families. Though they almost  certainly didn't think about it like that,   I would bet. Denisovans lived further east too,  according to the proteins recovered from this jaw  

found in Baishiya Karst cave. Breathing  in the thin air of the Tibetan plateau. In warmer climates though, tucked away on the  island of java, Homo erectus was still living   along the Solo River. No doubt living a similar  life to their ancestors who entered the region   well over a million years before. Probably unaware  that they were just over the seas from two other   groups of hominin, Homo floresiensis and Homo  luazonensis, from Flores and Luzon respectively. As you can see this is a really incredible  moment in the evolution of our species,   there's just so much going on, so  many different forms of hominin   leading slightly different lives in in  different regions, all Around the World. In between all of these finds, all these  various forms of ancient human sits   South Asia. Modern India, Pakistan, Nepal,  Bangladesh, Sri Lanka. So who lived there?

For the past three months I've  been working away at this problem,   reading paper after paper, interviewing experts  from different fields, and uh it's complicated,   it's really complicated. I think South Asia  is often sidelined in discussions of human   evolution. For some reason it just doesn't  get the same attention as Africa or Europe   or southeast Asia but I have come to believe that  it is in many ways the most interesting region. A   region that gives us a real insight into just  how messy and convoluted human evolution was. Obviously the first line of evidence we  have when we're trying to discuss who   was living in a specific region, what kind of  human, what kind of hominin are the fossils,   the literal remains of humans that  lived in that place in that time,   and this is what makes studying  South Asia so challenging. Hominins have lived in the region for probably  two million years, maybe even 2.6 million years  

and yet from that early time down through  to when modern Homo sapiens arrived. We   only have one cranium, one fossil. The  Narmada cranium. Fortunately for me   and this video I got to chat to Professor  Sheela Athreya who's studied it in depth.

[Stefan] okay let me share  my screen here so we can see,   so yep, so who is this who are we looking at here? [Sheela] We are looking at a hominin  from the pleistocene in central India   and those are the three most definitive  things that I can say about it. [Stefan narration] At 1300 kilometers long  the Narmada is India's fifth longest river.   The source of the River springs from the  ground at the Narmada Kund temple in Madhya   Pradesh before winding its way down through  the mountains, into the state of Gujarat,   and out into the Indian Ocean. On December  5th 1982, outside the village of Hathnora,  

Arun Sonakia unearthed the only archaic human  remains found in South Asia. Unfortunately the   skull was found in a secondary deposit which  means the river had washed it away from its   original location and deposited it elsewhere, so  it's been removed from its original context and as   a result the date range for this skull is really  quite broad, between 46 and 236,000 years old. [Stefan] Even though it's the only fossil  that we have, it's a sample size of one,   I think we are fortunate it does  seem to be a really interesting   fossil though there does seem  to be a lot going on with it. [Sheela] Yeah that's definitely fair to say. I  mean one of the uh the first morphometric study   of it that, you know, did a complete statistical  multivariate statistical analysis of the specimen   by Kenneth Kennedy at Cornell University,  demonstrated that it has one of the highest   cranial heights and that's measured from the  base of the cranium at a point called basion   at the back of the foramen magnum, up to the top  of the cranium. It has one of the highest basion   bregma heights, so one of the highest crania  of, if it's a homo erectus of homo erectus,   it's outside the range actually. But at the same  time you can see it has a very sloping frontal  

bone behind those big brow ridges and it has um a  very rounded kind of angular back of the cranium.   So living humans have a more vertical back of  the cranium and that's what makes our skulls   look so round and this one, even though it's  got very rounded features at the top which do   make it seem globular, at the back it's still  angular which is more like Homo erectus. This   individual is inferred to be a female but that's  that's based on a limited reference sample, it is   assuming that there are more robust individuals  out there and then this is less robust. [Stefan narration] The cranial capacity is also  within the range of modern humans, the average of   different estimates works out to about 1288 cubic  centimeters which is basically the average for a   modern woman now. So where does narmada fit on our  evolutionary tree, approximately, you know these  

things are nuanced but where approximately  does it fit on our evolutionary tree? [Sheela] If we treat treat the African Homo  erectus as one group and we treat the Asian Homo   erectus as a completely separate group and the  Europeans as a third group, Narmada is not typical   of any of them. But it's not so different that we  want to come up with yet another species name, and   so when the analyses are run that both the African  and Asian specimens from a certain time period   are called Homo erectus, Narmada the fits right,  in it has some African and some Asian features. [James] But also just thinking about  how how you might have interactions   between adjacent populations South Asia is  kind of interesting, because to the West   it can get cut off during arid phases  because the deserts. It's very difficult   to move east west. On the Eastern  side you've got the other problem,  

you've got some of the wettest landscapes in  the world and when they get wetter that must   be very difficult, you've got mountainous  really humid forest to try and traverse,   but those areas might be accessible during more  arid phases. So you've got this pulse , when you   know when you might have interactions from either  side and that could fit well with what Sheela   would suggest of that oh actually you've got  some some Western contact some Eastern contact. [Stefan] What do you think that says about  South Asia's position in our human evolution? [Sheela] You know the title of the paper I  think South Asia was a geographic crossroads   the other thing I think it says is more  about how we partition variation. And so   if we partition variation based on the  geographic um you know, things that are   very geographically disparate. We're going  to say lo and behold they are very different   and if you ignore all the all the population  areas, so South Asia and Central Asia,   um then your you know your models are obviously  lacking something but you're also missing the   point of what we're supposed to be studying  which is how did humans vary in the past,   I think that's what we're supposed to be  studying, I don't think we're supposed to   be asking how many categories were there  in the past. What we should be asking,  

what is interesting to ask, if we really want  to understand the evolutionary history of humans   isn't the labels again, it's the processes  what are that evolutionary processes that   are shaping us, right? To me that's more  fascinating. I would love to know what   environmental and climatic factors, maybe even  technological factors, raw material availability,   subsistence patterns, what were the things that  were shaping these populations in the past? [Stefan] So there we go, the only human cranium  from the middle pleistocene in South Asia really   shows it to be a bridge between two groups of  distant hominins, what's going on in Africa,   what's going on in in East Asia. It's  mix of features East and West, modern,   archaic really resists an easy classification and  that's probably the point we should be taking away   from it. Whoever lived in South Asia during the  middle pleistocene was really at a crossroads   both in in time and geography. They're  going to be influenced by a lot of factors,   some of them external but also some of them  internal, this was no evolutionary dead end. With only one fossil we have to look elsewhere  for Clues as to what was going down in South Asia.

Naturally, this being the Stone Age we're  going to look at stone tools. Now assigning   stone tools to a particular hominin in  the absence of fossils is really tough,   absolutely fraught with nuance but we  can paint with some really broad strokes. In this middle Pleistocene there are two  families of tools that really stand out.  

The first are Achulean stone tools,  the absolute classic achelean artifact   are these large bifacial hand axes,  but they did also produce cleavers,   they did also use flakes, but the  hand axe is really characteristic. Early examples start to appear around  1.75 million years ago in Africa and   are associated with the evolution of bigger  brained hominins like Homo erectus and later   homo heidalbergensis. That's family  number one, that's the Acheulean. The next family of stone tools the next  development occurred between 400 and 200,000   years ago these are called middle Paleolithic  tools. The idea here is that now flakes are   the star of the show. The knapper would create  a striking platform on the bottom of the rock,   they would then shape the core to create the  outline of a tool, then with one precise bosh   the perfectly shaped flake is removed and now  you have your spear point or whatever you wanted.  

Archaeologists call this the levallois  technique and it's associated with the   evolution of homo sapiens, neanderthals  and denisovans. Multiple groups used them.   These changes may seem kind of small to  us but as archaeologist Gopesh Jah and   James Blinkhorn will explain, these are legit  technological breakthroughs, no doubt about it. [James] To explain and particularly  this shift from Acheulean technology   to accomplish levallois and middle politic  technology. Acheulean tools are bifaces,   you can imagine it a bit more like a sculpture,  in that you start off your block of marble,   you chip things away until you realize this is  the shape that I wanted in the end. Whereas,   you're doing a lot of that shaping of levallois  technology but then you've got this one final   strike which is make or break it, into the thing  that you're you've been preparing towards. So it's  

cognitively more complex to do that, you've got to  think the steps in advance and all the different   parameters you can control, but it gives you a lot  more control of the shape and size of the flake   that you're removing. Presumably because that's  desirable for the tool that you want to make. [Gopesh] and throughout the middle pleistocene  you have so many industries where people are   shifting from this heavy tools to the lighter  tools, and that may have something to do with   localized adaptation. Like when there is a  huge scarcity of resources, I don't want to   travel with these huge artifacts. I I want to  be more efficient in terms of adaptation and   hence I rather focus on these smaller flakes than  these heavy artifacts and these smaller flakes   can be of an amount of types like that made in  different technique, this and that, this and that. [Stefan] Okay let's look at some South Asian stone  tools. These are stone tools from Attirampakkam,   these are argued to be middle Paleolithic tools,  those levallois stone tools. These are cores that  

have had flakes removed. In the middle here we've  got these levallois points and at the bottom here   we've still got some hand axes being produced.  What's so tantalizing about Attirampakkam is that   the oldest layer where these stone tools have  been excavated dates to 385,000 years ago which   is extremely old. Making it one of the oldest  middle Paleolithic sites in the entire world,   maybe even the oldest middle Paleolithic site in  the entire world. These are some more stone tools   from slightly further north in Andhra Pradesh,  apologies for almost certainly saying that wrong.   Again here we've got some cores here, G and H  some levallois points. C, D, E and F are again  

hand axes, that tradition is still going on here.  Quick note here though, notice how E and F are   very small hand axes, that's going to be important  later. These all date to 247,000 years ago. So there you go we have very early  levallois technology in South Asia   probably made by a hominin that was  like us Homo sapiens, like neanderthals,   like denisovans. The hard thing is without human  remains we can't really say much more than that. [James] There's absolutely no reason why,  you know, the middle middle pleistocene   homo population that we've got at Narmada is  broadly similar to Neanderthals to denisovans,   and to my mind probably not that different from  Homo sapiens either. So probably under the right   circumstances would have would be in a position  to innovate similar sorts of technologies.

[Stefan narration] As you can see though  these industries are kind of transitional   there's still some Acheulean tools being  produced alongside middle Paleolithic tools.   This suggests that this is really a local  innovation, independent innovation going   on down here in South Asia. But how long that  transition lasted and the factors influencing   it is uh subject to huge debate because the  picture is actually even more complicated.

[Stefan] Do the Acheulean and the middle  Paleolithic overlap for a long time in South Asia? [James] Yeah, yeah that's one of the key areas  where South Asia is really quite weird. It's   got the youngest Acheulean industries in the  world. So in East Eastern Africa it's at Mieso   around 214,000 years ago is the youngest latest  Acheulean there. In Arabia you see something   slightly younger around Dawadmi it's 170, 180  uh. At Bamburi and Patpara in the middle of Son   Valley uh, which is in central India, you're  dating to 140 to 120,000 years ago. So that's,   you know a hundred thousand years ago  after it's disappeared from Eastern Africa.

[Stefan Narration] So we have a site  with the earliest examples of middle   Paleolithic technology, other sites  with the youngest examples of Acheulean   technology. What kind of forces  could have driven this variation ? [James] So and I think one of the things that  kind of muddies this issue and even, again I'll   probably refer quite a lot to Eastern Africa  here but actually even in the young Acheulean,   like some of the most recent Acheulean in Eastern  Africa you find the appearance of levallois   Technology, this key key aspect of the middle  paleolithic, but often in low frequencies compared   to this focus on bifacial technology which is  still the dominant aspect of the assemblage. At   some point that's that switches, so it's not just,  it's not always just a presence or absence sort of   argument is my point. Sometimes it's proportional  with reference to the assemblage that it's in. [Stefan narration] The existence of  these two technologies alongside each   other for such a long time is challenging though.

[James] and this is where the findings from  Attirampakkam kind of jar with that otherwise   quite simple model as it's suggesting that  there's perhaps within the region what 250,000   years of overlap between Acheulean technology  and middle paleolithic technology yeah um [Stefan] which is just such a colossal,  it's easy to get lost in the numbers,   but that's such a colossal amount of time. [James] I mean uh it's almost as long as we  would, you know, recognize our species to exist,   existed for, that there could have  been this overlap, which is is huge   and it I find it difficult, I  find that difficult to explain. [Stefan narration] My first instinct upon  learning that there was two different   technological traditions surviving  for a long time alongside each other   was that there was multiple  different hominins producing them. [James] I don't see the immediate need to jump  that they must be different populations doing   that. um I think that's partly because, you  know, without either genetics or some fossils   to go on we can keep on populating with more and  more different hominins if we like. So for me,  

it's why was it happening down on the south  east, and why didn't it spread elsewhere and   that's that question of was it a was it really  an enduring thing, that always persisted there   or was it momentary and related  to some very specific conditions? [Stefan narration] Climate  and environment obviously   two huge factors that could have played a role. [Gopesh] So India or South Asia comes under  this school called oriental z,one Oriental okay   which is which has just so many pockets of natural  resources which are evergreen, okay. In a way like   even when there's certain kind of a table turning  environmental shift is happening around the globe,   becoming super arid conditions but you always  have these pockets which can support hominin   populations and India has, not India I would say  south Asia, has multiple set of these pockets.   We are not traveling for sake of traveling, we  are traveling in search of resources or better   habitats but when you have one which supports  your needs, which nourishes you, caters you   what you seek, which you don't need to go far off  regions. You can be or you can build that cocoon   or ecological cocoon where you grow and grow  and grow and does not have to be in contact. [Stefan narration]as I said at the start Homo  erectus was still around at this time one hundred   thousand years ago on Java. But that's sort of  easy to explain because Java is so tucked away  

on the southeast of Eurasia. It wasn't an island  at this time but it's still extremely remote,   extremely mountainous region. So their survival  in that area is sort of simple to explain in a   way. But explaining the Persistence of Acheulean  technologies in South Asia uh is more difficult. [James] uh because when you note 250,000 years  of overlap or potential overlap between middle   paleolithic in the southeast and late Acheulean in  kind of north and west, what was separating them? Even after the disappearance  of Acheulean it doesn't get   any easier to untangle what's going on.  Archaeologist Praveen Kumar talked me   through some of the most important sites at  this time one hundred thousand years ago. [Praveen] That is the middle Son valley,  right now I'm working in this area,   this eastern part of the India.

[Stefan narration] Sites like Sandhav, which has  pretty good evidence of a homo sapiens population. [Praveen] it's an interesting Discovery  from the Sandhav because tanged point   is in Africa North Africa, Aterian points  are actually associated with modern humans. [Stefan narration] The tanged points  that Praveen and others excavated here   at Sandhav called Aterian points are  especially interesting because at the   same time they're found across North  Africa and are associated with modern   Homo sapiens. Could this population also have  been present at the same time in South Asia? [Praveen] Yeah so in in Western India  and coastal region this time discovery   of this tanged point uh a date, the date  of this tanged point is very interesting.   So this tanged point is byproduct of modern  human? I I don't know it's it's big question? [Stefan narration] This point is great  evidence of homo sapiens in South Asia   at that time but at other locations middle  Paleolithic assemblages still have small   diminutive bifaces, just like the ones from  Andhra Pradesh that was 247,000 years old.

The youngest of these diminutive bifaces was found   just down the road from Sandhav  and dates to 69,000 years old. [Gopesh] it's 69 kilo years [Stefan]oh wow that's really young [Gopesh] 1.5 to 69. yeah that's  what we are talking about. [Stefan]damn.

I think the real archeology nerds in my  audience out here can see why this region   is so interesting. At every single step  it just forbids us from forming any simple   conclusion. It's like oh we have Aterian  points so homo sapiens are in the region,   right? Well maybe but somebody's also  still producing bifaces and they're found   alongside middle Paleolithic tools. It's just  a it's just so complex, I absolutely love it. There's probably only one technology which is   really going to help us get to  grips with all this diversity. Okay this paper is what started my whole obsession  my whole South Asian rabbit hole, deep dive,   'Using hominin integration to trace modern human  dispersals'. Basically using evidence of archaic   genetics in modern populations, modern Asian  and Oceanian populations to try and peel back   history a little bit and and understand  what was going on deep in pre-history.  

I reached out to Joao Teixeira  author of the paper to learn more. [Joao] The paper we wrote was essentially  focusing, or the idea was to focus on Island   Southeast Asia. When we, when we try to unpack  sort of the signals of Archaic introgression in   island southeast Asia we realized, we just have  to, you know, pull the movie backwards and sort   of like look of what what was happening before,  to try to fit it all together and one thing that   I want to make clear is that there's a myriad  of alternative models that could explain the   data and we have to sort of combine the pieces  that we find with models that make sense from an   archaeological point of view. Because this  is a perspectives paper it's really taking   other people's work and sort of combine  different lines of evidence to sort of make,   try and make a cohesive you know view. But I  mean it's mostly going to be wrong. Probably  

somebody's gonna show us that they're very wrong  in maybe you know, one year or two years but   for now I would say most things that are there  genetically, I think they're they're holding. [Stefan] As you can see from all of those  caveats the picture is very complex,   but the clues that geneticists have  unearthed are really intriguing. [Joao] There are a couple of papers that had come  out just before we wrote our paper, one of them   by Browning et al in in cell provided evidence  for two episodes of admixture with Denisovans,   uh and the way they saw this or the  way they infer these two episodes   is that the the admixing Denisovan  populations were genetically distinct.

So they found that mixture with like a  high affinity population to the altai   genome, right? From the fossil or from the  pinky finger. But we yeah but they also   found evidence for a more distant sort of real  distantly related Denisovan like group which   they reported in Australopapuans, so people from  New Guinea and Australia, but also South Asians,   Gujarati you know Punjab. Okay so that's one  paper, and then another paper tried to model   Neanderthal and Denisovan admixture with modern  humans using multiple demographic modelling and   deep learning and so they tested like different  plausible scenarios given what we know,   more or less, you know with these processes  or like sort of limiting to a decent amount   of models that would would be plausible, and they  they found support for two distinct models which   both included admixture from a group which was  equidistant between neanderthals and denisovans,   in the ancestors of South Asians,  East Asians and Australopapuans. So you can imagine as that sort of  radiation of modern humans went East   in Eurasia and before they split they sort of  received this genetic input from a population   that sort of, you know, was genetically  in between neanderthals and Denisovans. [Stefan narration] So there you have it, possible  genetic signals of a denisovan-like population   or something in between a denisovan and a  neanderthal, equally related to those groups.  

They gave this group The placeholder name extinct  hominin one and based on the modern populations   that have this admixture they propose that extinct  hominin one lived in the region of of South Asia,   everyone east of that point seems to have uh that  genetic signal. So that makes a lot of sense .   When we consider South Asia's position  geographically it does sit right in between where   we know neanderthals are living, where we know  denisovans are living. So some population that   is is related to both is entirely plausible. It's  entirely plausible that extinct hominin one was   making those tools in South Asia, though obviously  we do have to interpret these results cautiously. [Joao] But now people move. [Stefan] yeah [Joao] So we're most likely wrong, but what I  think it's important is that yes that that is   possible that some of the the these mixing events  that we're detecting are not necessarily like   from these discrete groups from which we have  like sort of a couple of genomes or a handful   of Neanderthals, but it's there's more to it  than this. It gets more reticulated than that,  

and we need, Now is that a fossil group that's  going to correspond to that? Maybe, maybe not. What this really shows is that neanderthals  and denisvans are not really a separate   species they're like two points on a spectrum  and in between those two points is obviously   going to be a group that is related to both  of them and that group may well have lived in   South Asia, that group may well have been  producing these middle Paleolithic tools. I've had to come for a walk to process all  my thoughts about this issue. This has been   the hardest video I've ever had to make, bar none.  You can see how long it's taken me by how often my   facial has changed, how often the background's  changed. I've tried to maintain a consistent   facial hair for the whole time and absolutely  failed. Every time I tried to create like a  

simple but but honest narrative about  what was going on in South Asia, I failed,   I absolutely failed. I couldn't construct  all of this information into a simple tale   and I realized that's because what makes South  Asia so special is the complexity. Sometimes   we can get so focused on what a neanderthal is  doing, what were Homo sapiens doing, what was   Homo erectus doing blah blah blah blah. We focus  in on one group doing something at one particular   time and it sort of creates this false impression  in our mind that these were truly distinct groups.   When we study South Asia, when we study the  literal geographic bridge between all of these   populations we can see human evolution  for the truly complex Beast that it was.  

From the Narmada cranium which is archaic and  modern and like Homo sapiens and like Homo   erectus, and to the tools where the transition  from Acheulean to Middle Paleolithic is so drawn   out over hundreds of thousands of years. DNA  evidence of admixture with a population that   isn't a neanderthal or a denisovans,  something in between these two groups,   you know. With South Asia there's no  easy answers, there's no simple models,   you have to confront the reality of evolution the  complexity of evolution, there's no way around   it. There's absolutely no line of evidence  will provide you with a simple conclusion.   It's incredible, I love it, it's  fantastic. Imagine what we're   gonna learn in 20 years more studying this  region. Mind-blowing, mind-blowing stuff. Making such long, research intensive videos would  not be possible without the help of nordvpn. I've  

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2022-10-28 17:15

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