**Becoming Human Part 2 of 3 "Birth of Humanity" HD (2011) โ€” Transcript & Summary | SozAI** Source: https://sozai.app/transcript/becoming-human-birth-of-humanity/ NOVA's 'Becoming Human' Part 2 traces Homo erectus, from Turkana Boy's discovery to the species' migrations, toolmaking, and the origins of human social life. ## Key Takeaways - Homo erectus was the first ancestor that closely resembled modern humans in body form and behavior. - Turkana Boy's skeleton and teeth provide direct evidence of growth, development, and possible causes of death in early humans. - Homo erectus's endurance running, toolmaking, and fire use enabled them to colonize large parts of the Old World. - Ancestral human social behaviors such as sharing food and communal care likely emerged during this period. ## What the video covers - Humans are tied to ape ancestors, and the video explores how the transition to our genus Homo began roughly 2 million years ago. - Lucy, a small-brained australopithecine from about 3.2 million years ago, illustrates the early upright-walking apes that preceded Homo. - Homo erectus appeared with longer legs, thinner arms, and larger brains, marking a major evolutionary step toward modern human bodies. - The 1984 discovery of Turkana Boy at Lake Turkana in Kenya by the Leakey team revealed the most complete early human skeleton ever found. - Paleo-artist Victor Deckers reconstructed Turkana Boy's face, showing a primitive skull with a lower forehead and smaller brain but a largely human-like body. - Dental analysis by Chris Dean showed that tooth enamel growth records can reveal age and childhood development, indicating Turkana Boy died around age 8 to 14. - Endocasts and brain studies by Ralph Holloway examine brain structure, including Broca's area, to infer early language and cognitive abilities. - Dan Lieberman's research suggests Homo erectus was adapted for long-distance running and cooling via sweating, which may have aided persistence hunting. - Molecular clock methods and fossil dating help place the timeline of Homo erectus migrations out of Africa and into Eurasia, including Georgia and the Caucasus. - Homo erectus used fire, shared food, and possibly developed communication and social bonds around hearths, marking early foundations of human society. ## Chapters 1. 00:00 Introduction: Our Ape Origins and the Question of Humanity 2. 04:05 The Great Rift Valley and the Dawn of the Genus Homo 3. 07:10 Discovering Turkana Boy at Lake Turkana 4. 10:00 Reconstructing Turkana Boy's Face and Body 5. 13:00 Age, Growth, and Dental Evidence 6. 23:00 Brain Evolution and Early Cognition 7. 28:20 Running, Hunting, and Migration Out of Africa 8. 40:00 Fire, Food Sharing, and the Birth of Social Life Answers ## Questions about this video What is Turkana Boy and why is he significant? Turkana Boy is a nearly complete Homo erectus skeleton discovered in 1984 at Lake Turkana, Kenya, dating to about 1.5 to 1.6 million years ago. He is the earliest and most complete early human skeleton found, revealing that early humans had body proportions close to modern humans. How do scientists determine the age of Turkana Boy at death? Dental specialist Chris Dean studied tooth enamel, which records daily growth lines like tree rings. These records, together with unfused growth plates on his limbs, indicate that Turkana Boy was still a juvenile, roughly 8 to 14 years old. Why might Homo erectus have been good long-distance runners? According to Dan Lieberman, Homo erectus had lost much of its body hair and could cool itself through sweating, allowing it to run long distances in hot conditions. This ability may have helped them hunt large animals through persistence hunting. ## Full Transcript โ€” Download SRT & Markdown 00:04 Speaker A humans without a doubt the smartest animal on earth yet we're unmistakably tied to our ape Origins millions of years ago we were Apes living ape lives in Africa so how did we get from that to this what happened what set us on the 00:29 Speaker A path to humanity the questions are huge but now there are answers at the threshold of humanity one ancestor contains tantalizing Secrets it is known as Homo erectus homoerectus had a slightly smaller brain slightly bigger jaw but it's basically 00:51 Speaker A us basically us almost 2 million years ago new finds are revealing the truth about the ancestors at the heart of our Evolution here were the Trailblazers who first left Africa the first fir makers the first Hunters these creatures were capable of 01:16 Speaker A analizing possible uses of tools and coming up with a technological solution to the problem how do you kill a big dangerous animal without getting killed yourself Homo erectus pioneered what it means to be human colonizing whole continents and creating the first human 01:33 Speaker A societies our ancestors began to care about what others thought and care about what that individual thought about them now new discoveries are bringing them alive as never before at last we come face to face with the ancestors at the 01:53 Speaker A birth of humanity right now on Nova major funding for Nova is provided by the [Music] following the Great Rift valy Valley of East Africa 2 million years ago these spectacular Plains and canyons witnessed a mysterious event the birth of the first ancestor we 02:45 Speaker A can really call human new discoveries are revealing a creature surprisingly like us a world traveler a tool maker a hunter Tamer of Fire creator of the first human societies amazingly the qualities that make us human began not with our own 03:09 Speaker A species Homo sapiens the true birth of humanity began much further back in time millions of years ago imagine the entire span of recorded human history about 5,000 years years taking us back to the Egyptian pyramids double it 10,000 years to the time when 03:38 Speaker A plants are domesticated and agriculture begins double it again 20,000 years Ice Age Hunters are painting stunning images on Cave walls and keep doubling six more times only then do we encounter our ancestor Homo erectus in Africa's great Rift 04:05 Speaker A Valley for millions of years this massive geological fault line running the length of East Africa was a stage on which our human evolution was played [Music] out it all started with the first Apes to walk upright on two legs about 6 04:24 Speaker A million years [Music] ago there were many different types all variations on the same theme aplike creatures with small brains the fossil known as Lucy is the most famous example here she is just 3' 8 in tall with a brain the size of a 04:51 Speaker A chimps for millions of years creatures like her roam the forests and grasslands of Africa but then something changed about 2 million years ago new creatures appeared with abilities never seen before in the animal kingdom meet Homo erectus a toolmaker 05:16 Speaker A and Hunter one of the first members of our genus the genus homo humans the transition to homo was probably one of the most important Transformations that occurred in human evolution arms got thinner legs got longer brains got bigger it was a huge evolutionary 05:38 Speaker A step from eight bodies to bodies like ours but what about the things that make us distinctly human creativity intelligence caring for each other how can we know when these got started with only skulls and Bone fragments to go on how could we ever 06:02 Speaker A know what those first humans were really like it would take a momentous find to shed light on their lives Lake turana Northern Kenya surrounded by volcanoes and vast expanses of baking desert in 1984 famed anthropologists Richard and me leaky were working at 06:30 Speaker A this remote Inland Sea I was actually on the east side of the lake and then Richard flew over and said you've got to come there's something really exciting as the first family of paleoanthropology the Leakes were used to Fossil 06:45 Speaker A fins but this was very special one of leak's team had found a skull fragment of one of those early humans he could tell from its size and shape it was Homo erectus and there was more than just a fragment so we started 07:03 Speaker A looking at this site on a on a more extensive basis and of course once we did we found the rest of the skull a complete skull was rare enough but it was just the beginning soon parts of the 07:14 Speaker A homo erectus skeleton which had never been found before started to emerge we couldn't believe it but we started getting pieces of ribs these were parts of hom Reus that nobody actually knew about nobody had ever seen before so 07:28 Speaker A every bone that came out of the ground was was something brand new to science and and we were looking at these things and it was really amazing and here they are the actual bones of a human ancestor who lived over 07:42 Speaker A 1 and A2 million years ago it's the earliest human skeleton ever discovered the Leaky called him turab boy his bones have revolutionized our understanding of the transition from a to human the really important thing about Turon boy is how complete he is 08:04 Speaker A we've got arms and legs and bits of his spine and his ribs and usually when we find these things we get very excited about one little bit of bone but that little bit can't tell us very much about 08:17 Speaker A an individual so having a nearly complete skeleton we can start to ask big questions the first big question was what did he look like his skeleton tells us he was 5' 3 in tall with a build closer to a man's than 08:36 Speaker A an ap's but how close paleo artist Victor deck specializes in painting and sculpting our human ancestors with precise anatomical [Music] accuracy Victor's going to add turab boy to his family of ancient faces at this stage of the game I know 09:07 Speaker A that turab boy is not an ape he is a very early true human and so here we have a modern human skull the faces are very similar to one another but turab boy's skull is a bit more primitive and 09:22 Speaker A has a lower forehead and a much smaller brain capacity Victor will build to boy's face muscle by muscle based on his studies of cadavers and modern Anatomy while his head may be primitive tono skeleton is surprisingly human his 09:49 Speaker A hips are a little wider his arms a little longer but his overall body shape is just like ours tonoy and erectus that's something that if you were to see from 100 ft away you would think well there's a large 10:05 Speaker A naked man there woman or or you know but it's a human it will take Victor a week to flush out tur boy's face meanwhile a team of animators is at work creating scenes that will bring tab boy and his people to life to make sure 10:29 Speaker A they they do it accurately they have Enlisted the help of Harvard Anthropologist Dan liberman they've had a more forward position of the PMS when they ran just slightly there you go the blue suited actors are there to create movement references for the 10:46 Speaker A artists in the final animations they will be replaced by Homo erectus bodies and action their heads and faces based closely on Victor's model as tab boy's forensically reconstructed head nears completion a face emerges that looks a lot like 11:11 Speaker A us now for the first time in a million and a half years here he is our ancestor the homo erectus called turab boy but what he looked like is only the beginning of his story to reconstruct his life we need to 11:30 Speaker A find out how old he was and if we look at his skeleton we can see that the growth plates on his limbs that would fuse when he's fully adult are all unfused so even though he's very tall we 11:45 Speaker A know that he's still growing the fact that toab boy was not fully grown has turned out to be a boon to researchers you can answer questions like did the boy grow up like a modern human or did he grow up more like an 12:02 Speaker A ape tur boy was already 5' 3 in tall when scientists compared his bones and teeth to ours he seemed to be about 14 years old but when dental specialist Chris Dean began to study his teeth he was in for a 12:21 Speaker A shock it turns out that all teeth fossil or not preserve a remarkably precise record of childhood this is a fossil tooth and we can see the enamel cap which covers the core of the tooth which is made of dentine uh 12:39 Speaker A dentine is just another word for Ivory and within the enamel you can see the rods which are running from the enamel denting Junction here out to the surface of the tooth enamel has a regular growth pattern like the rings of a 12:54 Speaker A tree under an electron microscope it looks like rods made of tiny beads each of the little beads along these prisms represent one day's growth because the cells which produce enamel are actually under the influence of a circadian or 13:10 Speaker A daily clock and those secretions during the day speed up and then slow down and there's a permanent record of that in every tooth so you can see rods running all the way through this tissue and every day along the rod there is a wobble 13:30 Speaker A where the tissue slows down and then speeds up so if you count the beads in these strings you can figure out exactly how many days that tooth has been growing when Chris looked at the fossilized teeth of tab boy he got a 13:47 Speaker A huge surprise turab boy wasn't 14 years old he was eight what that implies is that the growth of the takana boy resembled more closely than of chimpanzees today to be 5'3 at age 8 turab boy must have grown 14:06 Speaker A up very fast at a rate closer to chimps than us a chimpanzee's childhood is short it is sexually mature at about 7 human childhood is longer we reach puberty at about 12 so as humans evolved from apes childhood was extended 14:30 Speaker A but what advantage could be gained by having helpless children around to feed and care for who take so long to grow up the mystery of prolonged childhood is at the heart of human evolution it may be related to brain 14:51 Speaker A size we humans have the biggest brains in the animal kingdom in relation to our body size they're so big big that most of our brain growth has to happen outside the womb or our heads would never get through the birth 15:06 Speaker A canal a long slow childhood gives our brains time to grow after birth and time to learn everything we need to function in our complex human societies that's the advantage of prolonged childhood for us at least but what about turab boy 15:29 Speaker A his brain was 9900 cubic cm smaller than ours but more than twice as large as a chimp's so was he on the way to thinking and Talking Like Us Ralph Holloway believes he was he's been collecting the brain endocasts of 15:49 Speaker A human ancestors for over 30 years an endocast is a mold taken from the inside of the skull which reveals the shape of the brain Ralph is particularly interested in something called the brokas area brokas area involved with memory functions executive 16:10 Speaker A functions but it does have a very important role to play in the motor aspects of speech in the brain of turab boy Ralph believes he sees evidence for something remarkable a change in the broka area tied to communication broka cat regions on the 16:30 Speaker A turab boy are fully modern in terms of their appearance it is good solid evidence for the having the ability of symbolic Communication in other words language it's a controversial idea and we'll never know for sure if turab boy 16:49 Speaker A could speak but e e e e e e e e and Africa was filled with it the one highquality resource that's probably most important for the evolution of the genus homo is meat and meat bribe products such as brain and Marrow and 21:15 Speaker A fat they're high in protein they're high in calories and they're easy to digest but the one problem with getting meat is that it's hard to get most Predators rely on strength or speed to kill the prey our ancestors had 21:32 Speaker A neither today we are on top of the food chain so it's hard to imagine the predicament of those early humans here was a slow moving creature with no claws or fangs easy prey for the hungry Predators around him this is a fossil forehead and brow 21:55 Speaker A Ridge of a homo erectus and on the brow rid you can see the bite mark of a carnivore well this reminds us that these homoerectus individuals weren't at the top of the food chain so how did turab boy a weakling 22:12 Speaker A with a big brain which needed calories get his meat homoerectus faced a problem how do you kill a big dangerous animal that has lots of meat and fat in it without that animal also killing you I think the answer to that was a very 22:27 Speaker A clever set of Innovations and that is endurance running and high activity in the middle of the day the ancestors of homo erectus small hairy Apes like Lucy were bipedal but probably didn't do much running but tab boy kind were built to 22:47 Speaker A run like us a this is an accelerometer Dan liberman believes they could run long distances because like us they had lost their thick coat of body hair and could keep Cool by sweating ha's not on this was the key to their 23:06 Speaker A success but how do we know if these crucial changes go back all the way to toana boy's time over a million years ago skin and hair are rarely preserved in the fossil record so to find out we have to look to a creature that's been 23:24 Speaker A intimately connected with hair for a long time the LA all animals seem to have some type of lice to parasitize them mammals have them birds have them even fish have types of lice but most other creatures have only one type of Li that parasitize 23:41 Speaker A them humans have one kind of Lous on their heads and another in the pubic area geneticist Mark stoning asked himself why the answer that seems obvious is that when we had body hair all over our bodies we had one type of 23:56 Speaker A Lies but then we became hairless until we only add hair on our heads and in our pubic region and so therefore you would have this hairless Geographic barrier to contact between the two Mark was surprised to find out that 24:10 Speaker A the human pubic louse is very different from the human head louse somehow in the past it seems to have come from gorillas because the pubic Li that is actually more closely related to gorilla lice now how it is our ancestors got 24:25 Speaker A pubic lice from gorillas I wouldn't care to speculate nonetheless one needs gorilla life in order to really work this whole thing out the most likely scenario is that when we lost our body hair the original human louse migrated to our heads 24:45 Speaker A leaving the pubic area temporarily unpopulated by lice when our ancestors had contact with gorillas perhaps sleeping in their nests or Scavenging their bodies for meat the gorilla louse colonized their pubic region eventually it turned into the human pubic louse of 25:08 Speaker A today so if we could find out when the human pubic louse and the gorilla louse diverged we would have a rough idea of when we lost our body hair fortunately there's a way to figure that out the genetic dating technique 25:25 Speaker A known as the molecular clock it's based on the fact that the sequence of chemical bases which make up DNA mutate at a regular rate it's just a very simple idea that the rate of change in DNA sequences is more or less 25:43 Speaker A constant over time and that means that you have a way of determining when two species last Shar a common ancestor by counting the number of differences in the genetic code of two species scientists can determine how long they've been evolving away from 26:01 Speaker A each other when Mark used the molecular clock to count the differences between the DNA of gorilla lice and human pubic lice he came up with a date for their Divergence the estimated date for the Divergence is roughly 3 million years 26:18 Speaker A ago that means long before turab boy maybe even around Lucy's time our ancestors had slowly begun to lose their body hair turab boy was mostly hairless just like us and that may be what gave him an edge over other 26:43 Speaker A Predators most animals are at a disadvantage in the midday sun because they overheat they can only cool down by panting and when they run fast they can't pant that means they can only run in in short Sprints quadrupeds can G for about 10 to 27:03 Speaker A 15 minutes and then they overheat but hominids can cool down by sweating they use their entire body like like a dog's tongue our hairless bodies allow air to circulate freely on our skin and cool us down as sweat evaporates this makes us 27:21 Speaker A one of the best longdistance runners in the animal kingdom Dan liberman believes this gave our ancestors the ability to hunt in a very unusual way it's called persistence [Music] hunting and he believes the modern ethnographic record can show us how it 27:43 Speaker A was done the Bushmen of the Kalahari offer us an insight into how Homo erectus might have hunted 2 million years ago the Bushmen know that at midday animals rest in the shade which is why it's the perfect time to be 28:05 Speaker A hunting once they locate their prey in this case audo the marathon [Music] begins their strategy is simple run it to exhaustion every time the animal tries to rest the hunters track it down and get it moving again they never give it a 28:32 Speaker A chance to cool down and the reason they can keep going is that they can sweat so if the theory is right the Bushman hunt may help explain how tab boy got his meat Homo erectus had come up with an 28:54 Speaker A Innovative way of feeding his hungry brain in this modern hunt the Bushmen ran in the fierce heat for over 4 hours the kudu was finally immobilized by heat stroke turab boy wouldn't have had steel tip Spears like the Bushmen but he 29:22 Speaker A wouldn't have needed them hom is probably hunted with Close Quarters weapons with Spears that were thrown at animals from a short distance clubs thrown rocks weapons like that they weren't using longdistance projectile weapons that we know [Music] of the homo erectus hunt was simple but 29:46 Speaker A effective it fed not just their larger brains but the growing complexity of that early human society there are other social animals but none quite like [Music] us Society is in every corner of our lives our relationships communication rules symbolism all the 30:16 Speaker A things that bind us together what's behind it why do we become so social could it have something to do with another Innovation something unprecedented in our Evolution building fires and cooking here we got erectus the first species that looks like us and I think 30:42 Speaker A only cooking can explain the magnitude of this change the earliest evidence that our ancestors deliberately used fire for cooking dates to long after taboy time but Richard rangam is sure homeo erectus was building fires much earlier now for the first time we had a 31:05 Speaker A species that was committed to living on the ground because they lose their climbing adaptations well how were they sleeping they had to be able to protect themselves from wild animals on the African Savannah full of predators who hunt by Night Richard believes turab boy 31:24 Speaker A and his people couldn't have survived Without fire and he thinks only cooking which makes food more soft and digestible can explain why Homo erectus evolves smaller teeth and a much smaller gut these things are compatible with the reduced 31:43 Speaker A cost of digestion produced by cooking food nothing else is as our ancestors reaped the benefits of cooking something else happened too at least according to rangam we became more social humans have this wonderfully calm temperament compared to chimpanzees say where did it 32:04 Speaker A come from we were drawn to a common place the fireplace rum believes we learn to share and communicate sitting around fires waiting for food to cook it's speculative but one thing is for sure in the homo erectus World new 32:26 Speaker A social relationships had to be evolving the bonds between mothers and children must have been very different from the Apes for example a mother Oran will not allow any other individual to take her infant will be in constant skin-to-skin 32:48 Speaker A contact with that baby for at least the first 6 months of life not a moment out of contact secure in this unbreakable mother infant Bond ape babies need less capacity to read the intentions of others than human babies whose bond with their mothers is 33:07 Speaker A surprisingly less secure the shocking fact is that human mothers abandon their infants much more often than AP mothers infanticide by a mother is more common among humans than any other higher ape maternal commitment is a lot more contingent in humans than 33:27 Speaker A it seems to be in other Apes unlike most primates human mothers share parenting with others a child's survival can depend on making itself appealing to a number of caregivers perhaps that's why human infants have evolved a uniquely acute 33:50 Speaker A sensitivity human infants are born connoisseurs of mothers reading her facial expression looking for signs of commitment we are born hardwired with an awareness of the intentions and emotions of others which is unique in the animal world when did humans develop this gift 34:16 Speaker A for attributing mental States and feelings to others and for caring about what others thought about them could these social instincts have developed with Homo erectus along with Cooperative hunting bigger brains longer childhoods and the use of fire perhaps tab boy and his people 34:41 Speaker A already had social skills that would be familiar to us here were intelligent social beings with an increasing capacity for cooperation it may be this that made possible another great achievement The Exodus from Africa for millions of years our 35:07 Speaker A earliest ancestors stayed on the African savanas but at some point they started to leave ancient fossil skulls and tools have been found as far away as China and Indonesia the question is when did they leave Africa and why 35:29 Speaker A why when turab boy was found scientists thought they had the answer here was a strong large-brained ancestor capable of an arduous migration he had the look of a World Conqueror in the mid 1980s we were thinking that a homonid like this one 35:50 Speaker A had left Africa but had done it maybe about a million years ago for decades scientists believed big strapping humans like turab boy left Africa a million years ago but new discoveries are showing the migration may have started a lot earlier than 36:11 Speaker A that dimini Georgia the mountains and plains of the Caucasus thousands of miles from the Great Rift Valley had never produced any fossils of early human ancestors but then an astonishing Discovery was made it was a lower jaw with teeth 36:38 Speaker A downward this way in the ground so when I started to clean those front teeth came to light it became obvious to me that we had found some kind of homade but what kind the jaw seemed to be a primitive 36:57 Speaker A form of homo rectus but at first hardly anyone believed it in ' 91 when we found this Joe this was lot of scientists were quite skeptical about it was it was very hard to imagine georia Caucasus to be on 37:16 Speaker A the map of the human evolution since then demoni has been put on the map of human evolution in a big way the site has turned up a Treasure Trove of homo erectus fossils they've transformed our understanding of who left Africa and 37:37 Speaker A when they showed that the first humans to leave Africa were much more primitive than turab boy people thought that homin that left Africa were very tall like turab boy with big Brands advanced technology and the Mani proved the the 37:55 Speaker A opposite at 4 and 1/2 ft tall they were smaller than turab boy with more aplike shoulders and a simple stone technology they are much more primitive they have small brains and same time they were using very primitive stone 38:14 Speaker A tools the next surprise came when they dated the site the ancient dimini landscape has been built up layer by layer over millions of years 1.81 million years ago massive volcanic eruptions deposited a layer of Ash the fossils sat on top of this ash 38:39 Speaker A so must have been slightly younger around 1.8 million years old to the vast majority of scientists who believe that all our ancestors evolved in Africa this was a stunning surprise how had a small primitive home Homo erectus migrated to the caucuses 39:01 Speaker A almost 2 million years ago long before taboy scientists now accept that as soon as Homo erectus appeared on the savannas of Africa they started to leave suddenly with the origin of homo erectus we get this shift in body shape 39:20 Speaker A and then boom They're Out of Africa right away the Georgia fossils proved that homo erectus left Africa much earlier than previously thought an even more provocative find shows the migration may have started even earlier 5,000 mil from Africa the island of Flores 39:48 Speaker A Indonesia in 2003 researchers made a discovery so strange nobody knew what to make of it they found the B B of A tiny human ancestor just over 3 ft tall even smaller than the dimini fossils they called this baffling new ancestor homo 40:11 Speaker A floresiensis and because of its tiny size nicknamed it The Hobbit this has created a tremendous amount of grief because we're not really sure of what we're seeing here uh the size of the hoppit brain endic cast is roughly 400 40:31 Speaker A CC's that's barely bigger than the brain of Lucy the famous bipedal AE from 3 million years ago it's not just a small brain and A Primitive looking face but the foot is primitive the hand's primitive the leg is primitive the lower limb is very much 40:49 Speaker A like zy skeleton that was a big surprise and in the cave where this primitive creature was found they also uncovered stone tools something Lucy never had people have for a long time said well you need a big brain to make stone 41:07 Speaker A tools uh well okay if homop Anis is making stone tools this creature has a brain the size of an orange clearly that equation's gone everything about these creatures is an enigma where did they come from and what were they some researchers have argued 41:25 Speaker A that floresiensis is just a dwarf population of modern people that suffered some kind of disease that caused them to both dwarf and have relatively small brains but when scientists took a closer look most saw no evidence of disease the stone tools and the shape of 41:45 Speaker A the face moved the focus to our old friend Homo erectus some researchers think that homo fanis evolved from Homo erectus but how did they get so so small something called Island dwarfism may be the answer isolated on islands with limited 42:06 Speaker A food large mammals sometimes shrink over time on flues there were once pygmy elephants the size of cows could the same evolutionary pressure have acted on Homo erectus to produce The Hobbit or was this mysterious creature descended from an even more primitive 42:30 Speaker A ancestor so perhaps we're sampling a period which is at the very beginning of the homo lineage so whatever The Hobbit was perhaps its ancestors were the very first wave of migration Out of Africa some unknown creature part bipedal ape 42:50 Speaker A like Lucy and part Homo erectus [Music] so if that's the case then what we see in Indonesia makes sense it's kind of a body that existed before human bodies became more modern what would push such primitive creatures out of 43:21 Speaker A Africa a key driving force behind the migration was probably a climate shift which spread grasslands from Africa into [Music] Asia and with the grasses went the game animals animals are going to be moving out of Africa and the homs will just be 43:44 Speaker A keeping Pace with those animals after all that's their livelihood of course our ancestors didn't know they were leaving Africa they just followed the animals they depended on through the cyani up into the middle e East and Beyond it's often been called an exodus 44:04 Speaker A but it really wasn't like that when people think of Exodus they think of the Bible or they think of migration they think of Europeans coming over here to the new world it probably wasn't like any historical migration this dispersal 44:17 Speaker A of humans Out of Africa the process was probably very very slow much like the spread of any other animal species into new territories you could imagine a group of homo erectus moving their range a kilometer a year in One Direction and 44:38 Speaker A doing that continually over a long enough period of time you can get the distance from Africa to Indonesia covered in say 15,000 years by a million years ago our ancestors had populated Asia from the caucuses to Indonesia and they were in Europe too as 45:03 Speaker A a recent discovery in Spain has [Music] shown Homo erectus had conquered the old world the fact that they made it so far with limited technology and relatively small brains makes them seem even more remarkable and their longevity was astonishing a 45:31 Speaker A few pockets of homo erectus may have been still Clinging On in Asia just 50,000 years ago that's a span of 2 million years our own species has only been around for 200,000 what was the secret of homo erectus 45:56 Speaker A success the amazing finds at dimini have given us one last clue one of the skulls belonged to an old man his Jawbone revealed he had lost all his teeth well before he died that was a real surprise it means that this 46:14 Speaker A individual survived two years without teeth for an elder to have survived that long without teeth must mean that others in the group were feeding him perhaps perhaps even chewing his food for him I love this story this was a remarkable 46:34 Speaker A testimony from the past about the quality of emotional life that may have characterized Homo erectus here is a tantalizing clue to what may be this ancestor's most important Legacy the instinct to look after each other and it helps us imagine tab boy's 46:58 Speaker A final day on Earth in the animator's scenario he starts the day out on a hunt but he has trouble keeping up with the hunting party why the evidence from his skeleton is that he was sick and in pain at the time 47:25 Speaker A he died if we look at his lower jaw we can see right here under the teeth that we've got a bit of an abscess and an infection that kind of an infection could have entered the rest of his body 47:38 Speaker A could have killed him an abscess that ate away that much of his Jawbone would have been agonizing turab boy is in so much pain he's unable to continue the hunt knowing he would be looked after perhaps he returned to his campsite to 48:00 Speaker A find Comfort among the females I think he was probably a miserable fellow um in a lot of pain and very dependent on on support and handouts so it was a species that already felt that he one of our 48:16 Speaker A weaklings that you know we love and must must protect and care for to have got him that far but however much they may have wanted to help him they would nothing they could do about the infection that was probably spreading through his 48:35 Speaker A body from what the evidence suggests I just always imagined him not knowing what was wrong with him and there's a sadness to it but ultimately from that comes this Immortal being his skeleton was so complete it is likely he died in water which would have 48:59 Speaker A protected [Music] him it's very unusual to get a skeleton because normally these things are eaten by Carnival and in this case it seems that the boy's body was washed into a swamp and so the carnivals never saw it 49:15 Speaker A and never destroyed it and it gradually decomposed and as the rivers flooded brought in more sediment buried it and you could see Footprints of hippos that had walked all over the bones and and some of the ribs and things were 49:29 Speaker A standing vertically instead of lying flat on the ground and you could sort of reconstruct the situation and how how the boy what had happened after he died and and why he was complet it was just it really was it was an amazing 49:41 Speaker A experience to see [Music] it for almost 2 million years his bones were preserved by the Earth their Discovery opened a window for us on an unknown world the world of the most successful human ancestor of all time Homo 50:04 Speaker A [Music] erectus they've revealed to us that mysterious moment when almost everything human was born our bodies Our Minds our emotions think of all we've become [Music] trace the threads of our Origins through the ancestors who went before they all 50:34 Speaker A lead back to taboy and His Kind the first humans [Music] this Nova program is available on DVD and Blu-ray at shop pbs.org or call 1800 play PBS [Music] [Applause] [Music] [Music] Topics: Homo erectus Turkana Boy human evolution paleoanthropology Leakey Lake Turkana Nova human origins early hominins fire use Study this video - [Flashcards from this video](https://sozai.app/tools/flashcard-maker/?from=transcript&id=92482) - [Quiz on this video](https://sozai.app/tools/quiz-generator/?from=transcript&id=92482) - 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