The Pleistocene Meets Middle Earth: The Significance of the Indonesian Hobbits in Human Evolution

okay well well thanks very much uh yes I I used to play a lot of Blues piano but that was mostly while I was a graduate student because it's a lot easier to get the blues uh but since my involvement uh working with uh the remains of homophoresiensis and this very exciting Topic in our field of paleoanthropology I don't really have much reason to play the blues so without further Ado uh I'll get started here this is one of the most exciting topics in in paleoanthropology or human evolution today and one of the reasons for that is just because of how so totally unexpected it was to the entire field when this discovery was announced uh most of us in the in the in the scientific world became aware uh in late October of 2004. when this uh publication in nature came out and on the cover is this small Cranium and jaw associated with the type specimen of what is now known as the species homo floresiensis or nicknamed The Hobbits for short uh and this uh skull was discovered along with a partial uh post Cranium or partial uh set of Bones from the neck down from this cave known as Liang bua which in the local language means cool cave uh and it it is a very wonderful place to work in the sense that uh it's almost got natural built-in air conditioning uh and so in the popular press this discovery not only shocked the scientific world because it was so strange it also caught the the attention of the General Public and because it was coinciding in some ways with the um the distribution of the of the three remain of the three Lord of the Rings movies uh it quickly became easy to refer to them as the hobbits uh being uh with their short stature and some scientists thought this was a really bad idea uh they thought and some still think the nickname isn't a good one but I tend to disagree with that I think even though I had nothing to do with the term uh Hobbits I think most people that are at least familiar with the Lord of the Rings understand what that means that it's uh a kind of human that is very different from us but uh still very special and if you think of the other human species that we're most familiar with that being the Neanderthals Neanderthal carries a a certain derogatory uh effect with it partly due to the historical circumstances of the discoveries and that sort of thing whereas Hobbits don't have that and so I think it's a very positive term in in relating to the general public who may not have uh all the knowledge about what goes on in in evolutionary biology it's a great way to get that concept across but also what's totally fascinating about the hobbits was that not just their Anatomy but what they were found with a whole collection of other animals that have uh are clearly extinct on the island like these pygmy stegadon which are a form of elephant as well as uh giant Marabou storks vultures things animals that we we had no idea were living together on Floors this recently as well as the fascinating animals such as the Komodo dragon which are still around today on Flores the world's largest living lizard uh and so this combination if we if we look to see where this is this was part of the the strange the strangeness of this was that I I admit I certainly didn't know uh where Flores was or Flores was an island in Indonesia until after this uh most of us know uh the islands of Komodo like I just mentioned the Komodo dragon is is known worldwide and the island of Komodo is actually just an off I just off the coast of Florida so if you go to visit uh to see Komodo dragons in the wild you actually go to Flores uh and then this is Indonesia in general this is where Jakarta the capital is so you can see it's on one of these Eastern Islands uh and you have to cross several sea barriers to get there uh either from west to east or from north to south now I want to point out you can see this light blue area from this Google Maps this is outlying uh the depth of the oceans here and so those light blue areas are much shallower and that's really important because during times of low sea level in the past these islands were connected up with the mainland with the Asian mainland and similarly Australia connected up with with New Guinea whereas these islands in here uh often termed the wallacian islands were never connected to either Mainland now that that has tremendous effects on the kinds of animals that live there and many years ago a very brilliant man named Alfred Wallace traveled around these islands studying the the animals and plants and other uh on a living there and for those of you who don't know Alfred Wallace was the co-discoverer of of natural selection with Charles Darwin and he independently came up with the same idea that Charles Darwin did although he didn't uh have the same degree of evidence to back it up but they actually co-published the initial paper presented at the Royal Society in in England on natural selection and Wallace came up with the idea from working in this part of the world but he also is considered the father of what we call biogeography or using the biological communities in the world around us to understand that history because everything has to come from somewhere and what he noticed he made the prediction a long time ago with without being able to go and actually measure the depth of the oceans here he used the distribution of the animals and plants to say you know what if we draw a line down here even though these islands are really close they've never been connected to each other it must be really really deep there because when we cross these this line here the numbers of mammalian and bird and reptile taxa diminish considerably and of course now we know that Wallace was correct this is very deep and so the fact that these islands here contain relatively small numbers of animals compared to either Mainland is really interesting and so it's not that easy for animals to get across either this line on this side or The Wallace Line on this side and prior to homophoresiensis it was generally thought that the only humans to ever make it across Wallace's line were Homo sapiens our species and basically the first time that occurred was probably around 50 to 55 000 years ago when members of our species dispersed and colonized Australia as well as many of the other Indonesian islands and others in Southeast Asia now it's not exactly true that we didn't know or or people in our discipline didn't know that there might be earlier human species living on Flores prior to this discovery it just wasn't very well accepted and in that respect I'll just tell a very short story this this could be a presentation in itself but approximately 50 years ago a Dutch priest by the name of father verhoven was stationed on Flores now he was a a Roman Catholic priest but his his other love was archeology and he would travel around Flores looking for sights and he would excavate them and at one site in the middle of Flores he found stone tools along with the bones of stegadon this uh extinct form of elephant and he also found uh tektites uh and with that evidence he made the claim that pre-modern humans must have made it to Flores and he referenced sort of java Java Man uh known as Homo erectus that we know we're on the more Western islands in Indonesia and he said that somehow a pre-modern human species probably Homo erectus must have got across Wallace's line 750 000 years ago no one believed him no one took it seriously this was followed up uh roughly 30 years later in the 90s by a group of Dutch paleontologists along with Indonesian counterparts and they confirmed that observation they use the technique to date The Remains called paleo magnetism and by itself paleomagnetism looks at the way the Earth's magnetic fields are pointing at any given one time and because of that it's a relative dating technique and you need to sort of know the whole sequence and so again people really didn't take it seriously until this paper was published led by Mike morewood here in 1998 where they dated the same sediments and the same areas where verhoven worked and they did some new excavations found the stone tools found the stegadon bones and this time used a radiometric technique to date the sediments and were able to show that these sediments were at least eight hundred thousand years old Bingo now the scientific Community starts thinking this is really interesting so with that finding more wood joined up with a group of other Indonesian scientists and began looking for another site on Flores to search for some of these early pre-modern humans they knew that they were there from the stone tools but they wanted to try and find some remains and one site that seemed promising was Liang bua which had been excavated many times since the 60s including by father verhoven himself but those excavations never went deeper than about two meters partly because they were hitting sediments that were sterile there wasn't anything in them and it's pretty dangerous to dig a hole much deeper than that unless you start Shoring up the the sides but with this in mind now the goal was to dig deeper see what's what's there this is sort of what it looks like outside of the cave uh looking outside from the cave and like I said it can be very hot and dry or very uh wet and humid depending on the season but inside the cave it's really quite comfortable and digging very deep excavation squares generally two by two meters wide and going down approximately 10 centimeters at a time okay very slowly uh recording everything that's found uh as the excavations proceed and every meter or so reinforcing the walls with with wooden Shoring to ensure that the sides do not collapse and roughly approximately between five and six meters they in 2003 uncovered this Cranium and mandible along with the skeleton that goes with it and what's really remarkable here is this is your hip bone this is uh your thigh bone the femur and this is your lower leg bone the tibia and then the fibula which is your other lower leg bone is right there and then the kneecap is still right there now why that's significant is because the bones are still articulated together a lot of times when we find very old old fossils you know many of the bones have long since been scattered around the surface and only a couple of them get preserved but this indicates that this particular individual after they died likely got buried quite quickly there's no evidence that it was buried intentionally but likely it sank down into some mud and was protected against scavengers coming by that might have moved things around and so when they pulled out all the bones that uh came from this particular area they had a reasonably complete skeleton missing a lot of the upper upper body but at least some many of the bones at least represented from one side but almost complete lower limbs from the hips down to the tips of the toes only a handful of Bones missing now the extraordinary thing about this skeleton is in that its stature was roughly about three and a half feet tall and that that is predicted by uh uh estimates based on various bones of its lower limb uh it would have weighed between 30 and 40 kilograms so for a modern human of of uh that side they're they're much heavier uh and that's based on some of the robusticities of the bones and most extraordinary the brain size approximately 400 cubic centimeters typically modern humans uh range between 12 and 1800. uh cubic centimeters neanderthals on average actually have slightly larger brains than we do often that's thought to be related to them uh living in in a cold climate for hundreds of thousands of years but in general humans earlier human ancestral species uh with brains this big we haven't seen in the fossil record uh you have to go back about two million years ago to find this and so when the charcoal that was found reasonably close to the skeleton was dated and the dates came back at 18 000 years old this is a real head scratcher sure if if the dates matched the dates coming from the other part of Florida is where the stone tools were 800 000 years ago this could be a little bit more palatable but this recent wow this had pretty much everyone in the field of paleoanthropology and related disciplines scratching their heads and so generally we we now know that although there's a lot of work being done on this to to uh uh find out exactly what the time period within this uh that these these Hobbits are occurring and generally these sediments there's no question they're all within the last hundred thousand years there's no doubt about that the question exactly is where uh within this range uh are they occurring and like I mentioned earlier lots of interesting fauna fauna being the other uh animals and and plants there uh of course the fauna that's there today is very different because Neolithic Farmers within the last three to four thousand years when they came to Flores and basically at many other Islands within Island Southeast Asia and on into Polynesia brought many animals with them pigs chickens uh grains for farming they also brought macaque monkeys Javanese porcupines civet cats all of these animals only show up in the sequence in the very top of the sequence within the last three to four thousand years when we get underneath these uh particular volcanic uh Tufts is evidence of volcanic activity on the island then we see stegadon we see Komodo dragon we see the hobbits we see these giant Marabou storks these vultures very very interesting group of animals and of course although we only find proportionally small numbers of human bone of the of The Hobbit bones we find tremendous amounts of evidence of their behavior which is from the stone tools Stone preserves much better than bone always guaranteed to find stone tools and in this case we have tens of thousands of stone tools basically in any given 10 centimeter layer within the layers that homophoresiensis has found we find so far well over a hundred individuals of stegadon uh along with thousands of stone tools and some of the the stegodon Bones have cut marks so there's no question that there's some butchering of these large stegodone remains and of course that also makes sense relative to finding the big Marabou storks and the vultures which are also scavengers and so with all this evidence the The Hobbit suddenly became by by no wish of their own both important and renowned and they troubled the councils of the wise and the great now this has this is not a scientific quote but I I picked it out uh and I think it's a great thing to describe uh how the scientific community and the general public reacted to this story and this this discovery I mean we have to keep in mind that it was really only in 2003 that the skeleton was found within a year from that point it was published in nature which is very fast in our field uh and of course now it's only uh eight years almost eight years since that time and and not only myself but many other scientists go around the world uh every year talking about this people are really interested uh in this story and part of it is because it's so bizarre and unexpected but partly it's because we still don't know a lot about it and we're going to learn more and more uh as we keep studying on it it sort of opened up an area within the field that we always knew that there was things going on in Asia but Africa since Raymond dart's discovery of the tong child when the shift moved from Europe uh in terms of looking for human ancestors to Africa Asia kind of has always taken a bit of a back seat even though there have been some tremendous discoveries there and so homophreiensis has sort of opened that up again and given us uh some more impetus to get out there and and get the job done to figure out what was going on in Asia now of course I wasn't I had no involvement with the discovery team uh no connection whatsoever I was as as interested in the homophoresiensis story as anyone else and was as at the time I was a graduate student at Arizona Arizona State University and as many of you were probably here for Dr Don johannson's talk uh Arizona state is known for its its program in in paleoanthropology so this was an exciting time so we sort of went from reading a bunch of Articles from what happened 50 years ago and this species being discovered and thinking that all these exciting discoveries always happened far in the past to all of a sudden have this exciting discovery that was really debated no one knew for sure what was going on it was a very exciting time and apart from just following it that way I mainly sort of went out my went about my business focusing on my field of specialization which is the evolution of the hand and in particular for my PhD dissertation I focused on the on the wrist uh and which may even be more of a surprise to really focus in I focus just on this part of the wrist which is which is the side of the wrist where your thumb is on and partly what I was interested in doing was understanding the changes that have occurred during human evolution and obviously we like to use our thumbs and we tend to think of our thumbs as being pretty important uh and so I wanted to look at that uh those changes partly because uh one thing you may or may not know but there's 27 bones in in each one of our hands and so that makes up over a quarter of all the bones in our skeleton and if you add your feet half of us in terms of our bony skeleton our hands and feet uh and obviously those are the areas that connect not only with the substrate in terms of locomotor behavior whether we walk on two legs or we move around on all fours they're also directly involved in locomotion so anyone that goes to the zoo to observe animals you'll know when you look at a giraffe or a zebra or you know you don't see them using their forelimbs to pick things up because their hands and feet are highly specialized for moving around on the ground uh but you go and see any primate and you'll see them grabbing and picking things up and pulling each other uh hair because they have their hands or or more manipulative and we also know that the anatomy of their wrist is a good just it's good Anatomy to to distinguish between apes and monkeys also great apes from lesser apes so those are chimpanzees gorillas and orangutans compared to Gibbons and siames and also African apes and humans from orangutans I was explaining earlier today that uh Thomas Huxley who was Darwin's Bulldog if you will who went around championing uh Darwin's idea of natural selection and evolution uh because he had great anatomical knowledge and one of the features that he used in those debates was the wrist because Darwin had suggested that because both chimpanzees and gorillas came from Africa that we might expect to find human ancestors in Africa and that were likely more closely related to African Apes than we are to orangutans and dar and and Huxley used anatomical knowledge and part of that was in the wrist because African apes and humans have eight bones in their wrist but orangutans and all other non-human primates have nine okay and so what what's happened uh within the human and African ape families two of those bones have fused to become one and so this makes it important that the risk can give us clues about uh who's more closely related to whom uh in terms of a group of closely related animals and so again as I mentioned for my dissertation I was focusing in on this this region so here's your your thumb metacarpal that's this bone right here your index finger metacarpal here and then this collection of four wrist bones here the trapezium trapezoid scaphoid and capitate there'll be a a quiz as you're leaving and you're not allowed to leave until you you name all these correctly no I'm just teasing uh well here's what it looks like in a chimpanzee okay and chimpanzees are our closest living relative almost 99 genetically identical uh but any one of us can can tell them apart that's the nice thing about genes versus morphology even though we can share all that genetic material there's a lot of differences uh morphologically that we can look to and so again you can see that apart from their changes in proportions and subtle changes in shape it's very easy to see that they're the same bone that we've inherited these from a common ancestor now the trapezoid when we look at it from the Palm has a very different shape to it basically the way that it articulates with all the bones around it in in US is very different than what it is in chimpanzees and chimpanzees are also look very similar to gorillas in this context orangutans and and other non-human primates so when we look at that evidence what that tells us is either that all of those other animals have independently time and again in each one of those lineages evolved this almost identical morphology right or more likely that's what the ancestral morphology is for all of primates especially for all of apes and that somewhere on the human lineage these changes have occurred now of course we can only test that for sure with the fossil record but in this case given how many lineages we have outside of the human lineage seems a pretty safe bet and so I was interested in using this Anatomy because one of the initial questions was well maybe it's because we just use our hands more and so that that shapes some of the morphology sort of as we're growing up uh because we're always grabbing things maybe it's having effect on how the bones grow but we actually have a huge amount of evidence from the developmental literature that that cannot be the case because by the time you're a 10 to 12 week old embryo these bones the trapezium trapezoid and capitate even though they're not even bone yet but the cells that will later become that shape have already organized themselves into those shapes okay so it's not just a question of hey we start banging pots and pans as soon as uh our mothers let us move around the kitchen no this stuff is already well in place and so I used a a three-dimensional technique because these bones are are hard they're not just you can't just take sort of a maximum length a width sort of the traditional measurements that we use in other parts of the body to understand these differences it was one of the reasons why they hadn't been studied a lot because it was really hard to figure out a way of quantifying that morphology and being consistent and so what I did was I I used laser scanners to create three-dimensional models digital models so just like you take a digital photograph in this case I was making a three-dimensional photograph of the of the bones and then using that digital information to it I'm always embarrassed to say but it's it's like in in kindergarten you learn to color in the lines so I basically colored in the lines for each part of those joint surfaces so in that case it it was very uh a little bit subjective but at the same time by doing that and following the curvatures that digital information could then be Quantified because it was it's actually already a mathematical model I may have just drawn on the delimitations of a particular surface but then I can calculate its area I can calculate its area relative to the whole bone I can also calculate its relationships with all the other surfaces by fitting planes to those surfaces and so it enabled you know we can look at this bone and this one and say yeah they look different but this was a way that then allowed me to quantify those differences and test them across some of these species and of course looking at every individual in any given species always looks a little bit different now I'm just going to show you quickly uh these were the bones that were recovered with the type specimen of homophoresiensis and in the original Publications uh all that was said was that there were some hand and foot bones and as I said that this discovery you know it made a lot of scientists scratch their heads because many scientists thought there's no way that that can be a primitive pre-modern human on Flores it just has to be a member of our own species that suffered from some sort of pathology that uh you know they were living 18 000 years ago but we know modern humans should be on the island by then they're on Australia 55 000. maybe there's some other explanation now in 2006 I got the opportunity to study uh the wrist bones from the skeleton now as I mentioned to you I had spent uh I guess around six years of my life uh focused in going around the world scanning these bones from different species uh without having a big fossil record and many of my friends and colleagues would tease me saying yeah you got no fossils you know and I kept saying Yeah but I know but apes are just so different we know that something had to have happened in the human lineage and it's only a matter of time we're going to find some evidence I expected that it it wouldn't happen until much much later but I really got lucky because here like I said here's the trapezoid again this is from that view from the Palm this is the same bone but just looking at it from a different direction uh and then same here and you can see that we look very different and and this is an early modern human kavsa from Israel roughly about a hundred thousand years ago this is kibara which is about an 80 000 year old neanderthal we can see that neanderthals and modern humans even modern humans from a hundred thousand years ago have this type of bone shape but chimpanzees gorillas orangutans that you can go on and on with other non-human primates have this other shape to them and this was very easy to then quantify with the samples so that although I'm just showing one individual here down here are their reciprocal parts for each individual that I measured so well over uh 250 modern humans and early neanderthals and upper palethic humans this is a pituitary dwarf modern human this is a pituitary giant very different from all the Apes and other non-human primates and of course if we look at the bone from the skeleton found at liangbua Cave I don't think you have to understand multivariate statistics to see that it looks a lot more like these ones than it does look like and if we move through the other bones that were preserved remember what I said earlier you know someone could say oh that trapezoid yeah it looks like an ape trapezoid well maybe it's an orangutan orangutans are in Indonesia this was actually a a reviewer's comment when we first were trying to publish this um but orangutans never crossed The Wallace Line at least there's no evidence of it but we also have the scaphoid and remember earlier I told you about Huxley and how he argued that orangutans have two bones called the Centralia and the scaphoid and they're not fused together they're joined by ligaments tough ligaments but African Apes including gorillas and chimps and other early hominin fossils this is from old of I uh referred to uh Homo habilis the handyman these bones have fused right and sure enough here on this Indonesian Island we find a fused scaphoid but with Anatomy that looks a lot more like apes than it does like us because these changes to this articular facet in modern humans and Neanderthals is due to that difference in the shape of the trapezoid because these bones all go together they all stick together they've got to get along right I often use the example to University students it's like when you live you move in with a bunch of other students right unless one of you kind of starts building outside of the house you've got to figure out a way of carving up all the space and the same is true within your hand once you've changed the shape of one bone the other ones all have reciprocal changes around them and so similarly with all the bones of the wrist from homophresiensis it shows the pattern that we haven't seen in in our lineage for well over a million years and of course many of these bones get missed because they're odd they kind of look like small stones we don't have a lot of them but after I was involved I I went to Indonesia and started going through a lot of the bones that were unidentified from every layer and so here's just an example this is coming from just one 10 centimeter layer this is the amount of bone that's in some of these layers and from this this is the the decapitate the wrist bone in sort of the middle of your hand from the main specimen well this is a second capitate that we're about to publish on which is identical in the morphology but it's actually even a little bit smaller and this one is associated with another Jawbone and no pathology gives you two lower jaws and and two of the same wrist bones those aren't in the pathological literature uh and yet so now we we do have evidence of this in more Avengers and that makes it a lot harder to explain that oh it's just because otherwise you've got mythology in all the individuals and if that's the case how how are they surviving remember Komodo dragons can can hunt they they can find you uh um and similarly uh we found additional uh wrist bones as well so this is one of the exciting Parts is that even from some of those initial excavations we're actually pulling out a lot more remains small ones but uh some of these small bones tell very big big stories so again sort of to summarize you know we have uh the morphology in in our species as well as neanderthals we have the morphology in in chimpanzees and other apes and then you know we have the morphology represented in homophoresiensis and of course it looks a lot more uh like the Apes now that doesn't necessarily mean that it's more closely related to them because it's just one part of the anatomy and keep in mind that on a superficial level gorillas and chimps and orangutans look a lot more alike each other than any of them do to us but were in fact more closely related to chimpanzees and then to gorillas and then to orangutans so again it's not ju it's not necessarily an indication similarity uh doesn't indicate close uh genetic relationships in terms of morphology and so if we map on the morphology that we see in Apes as I said earlier it suggests that this is the Primitive condition so at the times where the ancestral species began to diverge into the lineages that led to the species we see today the common morphology was likely the morphology in the ancestor and that the changes that we see in US probably evolved after we diverged our ancestors diverged uh from this from the the uh chimp human ancestor and so by looking at the morphology that we know from the hominin fossil record again we can see that this change these changes to the hand probably occurred sometime before the lineage that led to neanderthals and the lineage that led to us diverged unless of course that same morphology evolved independently in both lineages sometimes that can happen uh but in this case it seems more likely that it was already there and so some of these earlier human species that also happen to be tool makers happen to diverge before this evolutionary change took place and so with relation to the the bones of homophoresiensis we can say with confidence that its ancestors diverged from our common ancestor with them before this evolutionary change happened exactly when we can't be positive but given what we know about when humans and and Neanderthals diverged and we share a common ancestor somewhere between 500 000 in a million years ago that likely it was at a time before then now of course the key missing element in here is is the anatomy of homo erectus which we know is in Africa and Asia and spanned a large portion of this time from about two million years ago up until a few hundred thousand years ago and so but we don't have any wrist bones from Homo erectus I call it job security of course I really want to know what it looks like but all I can do is make the best predictions we can with the available evidence uh and so we we can't be sure but again the wrist is very important here because it it helps demonstrate that it's extremely unlikely that we can explain these these individuals as pathological members of our own species because they have Anatomy that essentially goes far far back in our shared human evolutionary history and so yes we can use hand morphology and risk morphology to distinguish between these different evolutionary lineages including Hobbits India and uh from modern humans and Neanderthals now why do we have these changes that's often a uh you know and my honest answers we still don't know for sure but we have some pretty good ideas about it and one of them has to do with if we sort of measure put on these bones these are essentially the lines of force from various muscles so when you move your thumb there's different muscles that your brain is telling to move well the way these joints all line up with one another is very different the the basic anatomy is the same but the way that they're positioned is very different kind of like an engine of a Toyota versus a Ferrari right it has the same components but one is a lot better for certain things uh so when we when we take a look at this we can see that this Anatomy that we see in modern humans and Neanderthals is a lot better for Distributing forces whenever we're engaged our hand in a in a grip that doesn't mean that this Anatomy can't do those grips but it means it's less efficient so a good example a good way to think about it is you can go to a zoo and you can see chimpanzees and gorillas in some cases uh go walk on two legs some of them do it for long periods of time and this happens in the wild as well and so there's nothing in their Anatomy that stops them from doing it but the energy that their bodies consume doing it is considerable compared to when we do it because from our neck all the way down to our lower back to our knee to our ankle all those joint surfaces shifted and the anatomy has adjusted itself so that we're very efficient when we walk around and distribute our weight right you can also look at it this way we're still capable of walking around on all fours right or climbing trees but when we do it it costs us more than when an ape does it because of these small specializations and I think the same is true here in the hand and so even though we know that stone tool behavior that we know that these early hominins are making and using tools they still have the Primitive Anatomy and it makes sense in this in this when we lay all this evidence out we can see that roughly around three million years ago we have very little evidence of stone tool behavior in in hominins at that time in hominins being early human species roughly about two and a half million years ago we begin to see it all over especially within Africa and we begin to see some changes within that uh tool complex around one and a half million years ago but we don't see clear indication of the the changes I've described to you in the wrist until the earliest evidence we have for it is about 800 000 years ago which coincides with the inference based on how we're related to Neanderthals this could be present earlier we just haven't found it in the fossil record but we do know that given the anatomy of homophoresiensis and also it makes tools that are more similar to these tools that its particular lineage was already on floor as a million years ago our species and Neanderthals just prior to when we we diverge uh start making what are known as Middle Stone Age tools which are a lot more complex but here we can see that this technology already evolves in a context where the evolutionary changes occurred to the wrist so it is a complex scenario but you have sort of a feed these feedback things happening where you're getting change in Behavior hominins begin using stone tools for a long time but within that context because the stone tools are helping them survive relative to their close relatives that aren't using stone tools if variation shows up in the wrist and it it helps with those tools there's a chance that selection can grab hold of it but clearly it's not that easy because otherwise we would have seen these changes happen a lot earlier because this is a lot of time we're talking millions of years here for some of these changes to occur and if we go back to the cave itself uh for the evidence you know we see that in the tools the tools that we find at Liang bua associated with homophoresiensis as well as the tools we find at the other sites on floor is the date to eight hundred thousand a million years ago are broadly similar to the tools that we find in Africa from Two and a half million years ago up until about 400 000 years ago when the Middle Stone Age shows up and if you or I got trapped somewhere in the in the wilderness these are the kind of tools that we first make right it's the simplest way you grab two rocks and you bang them against each other and you get a sharp piece it's it's not that difficult uh and a lot of times it's economic and many modern human hunter-gatherer groups still do this today and so again this final sequence the fact that even though we don't have a lot of evidence yet in between these times from a million years and 800 000 years ago on Flores up until the last hundred thousand the story at least is starting to make some sense it's not as incredibly bizarre as it was uh when the discovery was first announced and again we also don't have to go too far to try and envision what it must have looked like for most of the pleistocene on Flores does that mean yeah are we okay the uh the hobbits are trying to speak to you uh so remember that we we seem to have this this ecosystem of of a large herbivore which is an elephant-like animal accompanied by these scavengers both the the giant Marabou store and the vultures we know this from the work of Dr Hanukkah Meyer who's a postdoc at the Smithsonian who's a specialist in Birds uh and so you can you know there's a big debate in human evolution about the role of hunting versus Scavenging even for us and it's it's a hotly contested debate but for a large part of our evolutionary history we were likely more often than not scavengers it's just easier you know you don't want to go and bring down a stegodon right it's a lot easier to wait until it's almost on its last legs and so in this context this is just a scene from Modern Day Africa where you have a large elephant that's died and you have here are the Marabou storks here are the vultures you add in Komodo dragon and these small-bodied small brain Hobbits and you have a good idea of the large body part of the ecosystem that remain fairly constant at least it looks like from the false record that we have right now from at least about a million years ago up until uh the last two uh within the last 20 to 30 000 years now I can't you know I focused on the on the wrist evidence because that's my specialty and that's how I got involved in the project but and and the risk evidence sort of played a big role just because of the timing of when it it came out in terms of this whole big debate and it helped convince a lot of people within the field of paleoanthropology because they they all study human osteology and they understand what those bones are supposed to look like uh but you know we also have a broad range of evidence from all the parts of the body uh from the brain work that Dean Falk has published showing that the inside of the cranium of homophraesiensis looks a lot like Homo erectus and not like modern humans with microcephaly or pathologies that result in small brain sizes we have a large number of Publications that have focused on the anatomy of the skull uh and in all cases this Anatomy groups homophresiensis with earlier hominins not with large-brained hominins like humans and Neanderthals new evidence uh dealing with the mandible the lower jaw and the teeth within showing even small bodied uh some of the smallest bodied modern humans today look very different than the two lower Jaws we have from leandua similarly the shoulder is more like what we see in Homo erectus and not like what we see in humans and the hip bones again look like pre-modern humans so it's not like we just have one piece of the evidence but there's multiple lines of this evidence and all of these are coming from different scientific experts that are experts in those fields and trust me we don't all get along uh in this case we we agree on some things but uh it's important to point that out that these aren't necessarily people that were all associated with the original discovery and finally also with the lower limb and and the feet and of course this is when you know we they were they were nicknamed The Hobbits because they were short right well it turns out they have big feet although that wasn't known at the beginning but it's a proportional thing where it's not that their feet are necessarily large but what's happened in in us because we're really good at walking upright what's happened in in the lineage that's led to uh humans and Neanderthals is that our thighs basically our lower limbs got elongated relative to our upper body and so that's why our legs are longer than our arms whereas if you look at Apes it's the other way around right so it's that difference in proportion all the bones are the same but those differences relate to those differences in our evolutionary histories but prior to that lengthening of the lower limb right it makes the feet then look proportionally large even though if you scaled the foot of homophoresiensis to its hip it would look just like us it's really that our thighs are so long that make it our feet look relatively smaller but for The Hobbit part it makes it it makes it a cute little story because as we all know habitat big hairy feet and so all of this evidence clearly shows that you know the hobbits are a close evolutionary cousin to us right we're more closely related to them than either of us is to living chimps but we're actually more closely related to Neanderthals and so again it raises the possibility which we're also learning from the genetic evidence as the one of these former speakers in this series like we talked about there were many lineages that went extinct in many different ways of Being Human and some of those ways clearly overlapped with our own species now we're the only species here now but we're beginning to get some glimpses both from DNA but also the fossil evidence that give us some of the highlights and hints of what how diverse are the Human family has been in the past uh five to six million years since we we diverged from the common ancestors of chimps so in this respect all of this evidence uh shows and these are the reconstructions done by John gerci of various fossils that are on display uh in the Hall of human Origins at the Smithsonian uh and and so you know we can see that yes homophresiensis in in many ways does look more similar to us uh and Neanderthals relative to some of the earlier hominin species like uh Australopithecus afarensis that Dr Johansen would have spoke about again we see some of these changes because we're more closely related we share a more recent common ancestor with the hobbits than we do with Lucy's species uh but again not all of the changes you know again showing that there's been an incredible amount of diversity within human evolution and we actually have lost a lot of that diversity and it's one of the reasons why all of us are so closely alike genetically and so having you know until you know how diverse the family has been it's hard to recognize how special it is and how uh unique we are as a species uh and it tells us a lot about what it means to be human because there's more than one way uh at least within our evolutionary history to be human and we're one example so with that I guess that's pretty but I I ended before it happened so that's good but anyway many many acknowledgments uh I want to thank my my colleagues at the national Center for archeology in Indonesia uh several colleagues in Australia at the University of Wollongong Stony Brook from uh New York obviously at the smithsonian's national museum of natural history and several credits for images so [Applause] we have time for a few questions if you raise your hand I'll come by with a microphone apologize for the noise and the speakers we have a wireless system we must have had some interference from somewhere yes you leveraged the Neanderthal Geon project and chance of a Hobbit Geon project yeah uh excellent excellent question obviously that's been a big uh uh it's been a big interest from the from the beginning of the discovery uh of wanting to get DNA uh so far several of the major Labs uh in the world both Max the laboratory at Max Planck in Germany as well as Alan Cooper's lab in Australia have tried on multiple attempts to extract DNA from the main specimens and so far no success now part of that is likely it's due to the tropical environment that the remains are found in right the reason why we have a neanderthal Genome Project and why it's been a success is because many of these fossils have essentially been buried in the freezer for fifty thousand years right so when you get into those Northern climates and you have that consistent uh lower temperatures it preserves the genetic material whereas when you're in a tropical equatorial environment where you're constantly shifting between hot and wet to dry the DNA degrades very very quickly and uh so in in terms of the remains from homo crazyensus I think most people right now scientists involved both on the genetic side and those of us that are working to find more evidence on the ground we're not hopeful at least in the in the short term for getting DNA unless we come across a very well preserved and sort of a uniquely preserved situation uh so I think for now we're going to have to relate relay uh rely on the on the morphological evidence uh before we get the molecularly but I think if we ever do get the molecular evidence it will be fascinating because if if we're right then we're going to get a window into the DNA of the ancestor that we share with homophysians because they would have had less changes relative to our genetic code since that time of Divergence so we'll see the pictures I've seen are pygmies their heads are proportional to their bodies how does their brain size compare to the habits uh well exactly uh all all modern humans of short body uh a short stature whether they're considered pygmies or whether they have some sort of pathology still have modern human body proportions and their brains are still very large relative to the body mass so in this way that's why uh homophoresiensis really stands out because it it basically has the anatomy that we predict generally for hominins when we consider all the earlier species their brains tend to be a lot smaller for their body mass and so in that respect uh homophoresiensis is an outlier and whether or not you find a modern human small body populations you know they have large brains they have long legs relative to their upper and they have these proportional changes that are shared among humans in neanderthals and other archaic members of the genus homo uh and that's another reason why we think homofresiensis must have diverged you know much earlier and simply diverge before many of these changes evolve was there any time before a million years ago when I understood you to say The Hobbit appears in the fossil record when sea level was low enough that it would have allowed them to walk onto Flores and if not what is the proposed method of arrival yeah uh well we don't have any evidence of homophoresiensis a million years ago what we have are the is the evidence of stone tools so we know we know from the fossil record that our own species right we know this from the genetics as well but our own species doesn't show up in Africa until about 200 000 years ago okay so one million years ago as long before we have anything like modern humans uh but somehow earlier pre-modern humans got to Flores now there's no indication whatsoever that if sea levels dropped to to a level that hominins could walk there right then we would predict that all sorts of other animals terrestrial animals would have gotten there too particularly small bodied animals now almost all the small body ecological mammalian niches on Flores are filled up by rats okay and one of the reasons there are rats that are you know small like your regular uh probably maybe the rat you have in in Kansas City I don't know uh but in in Washington DC and in New York we get these larger Rats the Norway rats sort of your medium-sized rats but Flores also has these gigantic rats that still live there today uh and so here you're looking at a a rat that's the size of a small dog or cat uh they you know they live in the forest they they filled up these different uh niches because no other small-bodied mammals were able to get there in the past and so because of that impoverished fauna sort of like what Wallace had noted uh there's no reason to suspect that at any time in the past the the sea levels were low enough for terrestrial animals including early humans to get there terrestrially so how did they do it well we don't know for sure but the main ideas are that somehow you would have had these natural colonizations which is the same way probably the rats got there and possibly the stegadon that at various times sometimes you get small chunks of land that break off other islands and can get swept down to another Island and sometimes these areas can be quite large and the issue here though is that the way that the sea currents flow in this part of the world even though they the distances between say the islands of Bali to lombok lombok to symbala symbolic to Flores are not very far the sea currents are so strong there that anything going east west to east is going to get swept South almost down to Australia so the more likely uh possibility is coming from sulawesi to the north right so maybe uh let me uh let me pull up a map quickly on that one oh the weights yeah that was a bad idea yeah maybe uh this one works a little bit so again The Wallace Line here there like I showed earlier there's actually been a lot more animals that have been able to get across The Wallace Line to sulawesi then there is evidence for Flores so it makes sense that you probably could have had something from Borneo Java sundaland yet across to sulawesi and then at some point swept down from the north here on to Flores because the as I said the currents are flowing north south uh but even with that in combination with when you think of things like tsunamis where uh you know people were transported to other Islands during the the uh tsunami disaster a few years ago and including uh a pregnant female who survived and and ended up giving birth uh so these things can happen now we're taught you know you need millions of years to foresee something like this and then a lot of luck for enough individuals that it happened a group to then be able to survive it still is very hard to figure out how it happened and you know the honest answer is right now that's all we've got just that those possible answers but it's the reason why I now spend about six months of every year in Indonesia trying to figure out how that happened find the evidence that will help us answer those very interesting questions any any ideas about um The evolutionary forces that caused them to be so diminutive in stature sure this has been a big debate in the uh in the scientific world because if we and it depends on what what we think uh they descended from right and so if we we consider bioge geographically the only choice is Homo erectus right but Homo erectus has many of the Adaptive changes in proportion that I was just talking about they have larger brains relative to earlier hominins in Africa not as big as ours but they're uh larger than 400 cubic centimeters they have the elongated hind limb and they're also found in this part of Asia so it makes reasonable sense that perhaps Homo erectus got here now if that's the case then we would assume that when they got to the island they looked a lot different than what they uh what homophoresiensis looks like and in that case then we would infer that these particular hominins underwent some insular adaptations due to the island environment they were living in but we also have to consider that we also have earlier hominins from Africa like Homo habilis uh and also outside of Africa at diminishi Georgia that don't quite have all the changes that we usually associate with Homo erectus and yet also had slightly smaller brains and so there's a possibility that there were other prominent species living in Asia the same time as Homo erectus that were slightly adapted slightly differently and so we just don't know that and it really will depend on the fossil evidence we recover from the sites on Flores that date to a million years ago so right now for instance we have a a five-year Grant through the Australian research Council that Mike morewood is leading where we're searching for that piece of evidence because we won't need much evidence but if we recover some of the physical evidence of the pre-modern hominin there we'll know was it large-bodied or not and that will allow us to make more specific predictions about what we think happened through the lineage that then ultimately resulted in homo residensis is the only place you've found the the hobbits that three or four meter squared excavation pin we saw and if so then you have so much more potential in just in that one cave now you know the level they're at um why should they be just a net cave no no exactly uh but but if that is the only excavation that you have found Hobbits the actual skeletal remains yes is that is that liangua in that particular cave now like I said uh uh that's not because we don't think they're in not anywhere else uh obviously they have to be but it's it is difficult to find sites that preserve the sediments that are the right date and then even then a lot of times most of our sites in in uh paleoanthropology are sites of human behavior right you're more likely to find the stone tools that are left behind uh or the butchered bones because humans generally uh are smaller in numbers and their overall population size is relative to other uh animal species they're just rarer and it can be hard to find them uh but obviously we're we're surveying on Flores uh my colleagues are also Excavating now on sulawesi trying to look for sites that have sediments in the appropriate ages uh to look for this whole because in essence that's the really great thing about this discovery right the fact of what it predicts for all the other potential within some of these islands and all the different evolutionary pressures that may have affected early hominins on those islands it really is uh uh a spectacular potential for looking at the ways that humans have adapted to prehistoric ecosystems uh and it's it's a it's a part of the world that we just never considered because we thought only when our species was able to build boats and figure out that oh yeah there's land over there let's start let's start moving over there we never considered that earlier humans could have colonized some of these islands even without advanced technology but clearly it happened and so if it happened once they had to get from somewhere and it's more likely they actually came from another relation Island so probably over the next 10 to 50 to 100 years we're going to see a lot of interesting examples come from this area of the world and what what I like about it relative to typically in our discipline in the in the history of paleoanthropology it's always about finding the ancestor the oldest uh you know we want the granddaddy right but sometimes in this case we're not searching for the ancestors because these these species over here are more like our cousins but they help show us the diversity of what it means to be our species and in that way we're not so much looking for the earliest this so that we can say that this is where we came from this is like saying hey we're trying to find our evolutionary cousins that we've lost touch with and sometimes they can tell us just as much about our own evolutionary history uh from their remains as something that is our Direct ancest or to Sherry we have a question over here on your left and due to the time this will be uh this will have to be the last question this evening uh very much correlating to the question about how they got to be diminutive uh does the tool size you say there's been the longer record and plenty of evidence of the tools yeah is there a scaling of them getting smaller through the uh stratigraphy or anything along those lines no uh but remember what I mentioned about the feet right their feet look big right but it's a proportional thing because the reason why they're diminutive is because of their their thighs their their lower limbs are short so homophresiensis at least from what we have the evidence of it is about the same size as Lucy okay but in this case uh its arms are still quite big and so it's it's hands it's although they're smaller than our hands absolutely proportionally they're not that small and so we don't see anything from the tools necessarily in the size of the tools to think that no that their hands were somehow so tiny uh that that would have uh affected the types of tools that they made we we don't see that uh and and generally again I think it's this proportional issue I mean yes they're diminutive uh and they're small relative to us but you know you know three and a half feet is small for our species but that's still a pretty large animal uh and and uh you know we're not talking about things that uh are really really tiny so in general I think in in terms of their hands and feet their hand and feet sizes are going to be more close to a small bodied modern human uh and just it's just that proportion because of their short lower limbs that make your stature look a lot smaller but also interesting along those lines is the small brain size right because uh we've always expected even though we know that at two and a half million years ago when we find the first evidence of stone tools in the fossil record we know that the early humans at that point did have brain size is roughly comparable so we know it's not impossible but we've always had this assumption that well yeah once they start making tools then the brains get big and it just naturally flows that we you know they evolved into us and the tools get more sophisticated the brain gets bigger they start moving around different continents and that's what's so exciting about homophoresiensis is it shows us it didn't necessarily have to happen that way because there we see what looks like reasonably evolutionary stasis even if they ended up did even if they did get smaller and evolve secondarily from slightly larger bodied and larger brain hominins it's still something that we would never have predicted uh based on our human egos right but based on everything else we know about evolution in the animal kingdom it seems perfectly reasonable so it's again it's a good way of how sometimes our evolutionary cousins can kind of uh pull us in a little bit on the way we tend to interpret our own evolutionary history thank you Dr taseri and thank you for attending tonight's lecture be sure to visit lindahall.org and sign up for the June 14th lecture on the history of the building of the first Transcontinental Railroad thank you and good night

Channel: Linda Hall Library

Views: 10,249

Keywords: paleoanthropology, Flores, Indonesia, human evolution, evolution, hobbits, Homo floresiensis, science, engineering, technology

Id: cyl_Z7_fr7A

Length: 72min 8sec (4328 seconds)

Published: Mon May 01 2023