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[Music]
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humans without a doubt the smartest
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animal on earth yet we're unmistakably
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tied to our AP
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Origins millions of years ago we were
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Apes living ape lives in Africa so how
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did we get get from
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that to
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this what happened what set us on the
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path to
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humanity the questions are huge but now
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there are
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answers at the threshold of humanity one
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ancestor contains tantalizing Secrets it
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is known as Homo erectus homoerectus had
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a slightly smaller brain slightly bigger
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jaw but it's basically
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us basically
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us almost 2 million years
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ago new finds are revealing the truth
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about the ancestors at the heart of our
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Evolution here were the Trailblazers who
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first left Africa the first fir makers
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the first
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Hunters these creatures were capable of
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analyzing possible uses of tools and
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coming up with a technological solution
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to the the problem how do you kill a big
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dangerous animal without getting killed
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yourself Homo erectus pioneered what it
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means to be human colonizing whole
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continents and creating the first human
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societies our ancestors began to care
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about what others thought and care about
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what that individual thought about them
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now new discoveries are bringing them
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alive as never before at last we come
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face to face with the ancestors at the
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birth of humanity right now on Nova
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[Music]
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the Great Rift Valley of East
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Africa 2 million years ago these
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spectacular Plains and canyons witnessed
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a mysterious
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event the birth of the first ancestor we
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can really call
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human new discoveries are revealing a
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creature surprisingly like us a world
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traveler a tool maker a hunter Tamer of
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fire creator of the first human
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societies amazingly the qualities that
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make us human began not with our own
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species Homo
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sapiens the true birth of humanity began
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much further back in time millions of
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years
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ago imagine the entire span of recorded
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human history about 5,000 years taking
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us back to the Egyptian pyramids double
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it 10,000 years to the time when plants
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are domesticated and agriculture
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begins double it again 20,000 years Ice
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Age Hunters are painting stunning images
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on Cave walls and keep doubling six more
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times only then do we encounter our
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ancestor Homo erectus in Africa's Great
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Rift
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Valley for millions of years this
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massive geological fault line running
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the length of East Africa was a stage on
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which our human evolution was played
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[Music]
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out it all started with the first Apes
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to walk upright on two legs about 6
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million years
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[Music]
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ago there were many different types all
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variations on the same theme aplike
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creatures with small
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brains the fossil known as Lucy is the
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most famous
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example here she is just 3' 8 in tall
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with a brain the size of a chimps
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for millions of years creatures like her
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roam the forests and grasslands of
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Africa but then something
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changed about 2 million years ago new
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creatures appeared with abilities never
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seen before in the animal
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kingdom meet Homo erectus a tool maker
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and
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Hunter one of of the first members of
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our genus the genus homo
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humans the transition to homo was
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probably one of the most important
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Transformations that occurred in human
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evolution arms got thinner legs got
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longer brains got bigger it was a huge
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evolutionary step from eight bodies to
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bodies like
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ours but what about the things that make
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us distinctly human creativity
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intelligence caring for each other how
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can we know when these got
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started with only skulls and Bone
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fragments to go on how could we ever
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know what those first humans were really
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like it would take a momentous find to
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shed light on their
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lives Lake turana Northern
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Kenya surrounded by volcanoes and vast
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expanses of baking
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desert in 1984 famed anthropologists
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Richard and me leaky were working at
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this remote Inland Sea I was actually on
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the east side of the lake and then
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Richard flew over and said you've got to
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come there's something really
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exciting as the first family of
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paleoanthropology the Leaky were used to
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Fossil
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fines but this was very special
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one of ley's team had found a skull
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fragment of one of those early humans he
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could tell from its size and shape it
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was Homo erectus and there was more than
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just a fragment so we started looking at
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this site on a on a more extensive basis
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and of course once we did we found the
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rest of the skull a complete skull was
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rare enough but it was just the
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beginning soon parts of the homo erectus
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skeleton which had never been found
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before started to emerge we couldn't
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believe it but we started getting pieces
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of ribs these were parts of hom rectus
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that nobody actually knew about nobody
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had ever seen before so every bone that
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came out of the ground was something
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brand new to science and and we were
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looking at these things and it was
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really
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amazing and here they are the actual
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bones of a human ancestor who lived over
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1 and 1/2 million years ago it's the
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earliest human skeleton ever discovered
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The Leaky called him tur
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boy his bones have revolutionized our
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understanding of the transition from
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eight to human the really important
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thing about turab boy is how complete he
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is we've got arms and legs and bits of
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his spine and his ribs and usually when
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we find these things we get very excited
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about one little bit of bone but that
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little bit can't tell us very much about
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an individual so having a nearly
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complete skeleton we can start to ask
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big
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questions the first big question was
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what did he look like his skeleton tells
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us he was 5' 3 in tall with a build
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closer to a man's than an
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Apes but how
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close paleo artist Victor deck
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specializes in painting and sculpting
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our human ancestors with precise
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anatomical
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[Music]
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accuracy Victor's going to add turab boy
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to his family of ancient
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faces at this stage of the game I know
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that taboy is not an ape he is a very
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early true human and so here we have a
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modern human skull the faces are very
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similar to one another but turab boy's
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skull is a bit more primitive and has a
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lower forehead and a much smaller brain
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capacity Victor will build T boy's face
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muscle by
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muscle based on his studies of cadavers
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and modern
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Anatomy while his head may be primitive
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turoy skeleton is surprisingly human his
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hips are a little wider his arms a
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little longer but his overall body shape
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is just like
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ours ton boy and erectus that's
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something that if you were to see from
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100 ft away you would think well there's
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a large naked man there woman or or you
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know but it's a
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human it will take Victor a week to
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flush out turab boy's face
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meanwhile a team of animators is at work
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creating scenes that will bring tab boy
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and his people to life to make sure they
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do it accurately they have Enlisted the
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help of Harvard Anthropologist Dan
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Lieberman they had a more forward
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position of the Palms when they ran just
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slightly there you
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go the blue suited actors are there to
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create movement references for the
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artists in the final animation
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they will be replaced by Homo erectus
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bodies and action their heads and faces
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based closely on Victor's
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model as tab boy's forensically
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reconstructed head nears
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completion a face emerges that looks a
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lot like
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us now for the first time in a million
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and a half years here he is our ancestor
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the Homo erectus called turab
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boy but what he looked like is only the
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beginning of his
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story to reconstruct his life we need to
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find out how old he was and if we look
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at his skeleton we can see that the
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growth plates on his limbs that would
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fuse when he's fully adult are all
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unfused so even though he's very tall we
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know that he's still
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growing the the fact that tab boy was
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not fully grown has turned out to be a
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boon to researchers you can answer
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questions like did the boy grow up like
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a modern human or did he grow up more
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like an
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ape turana boy was already 5' 3 in tall
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when scientists compared his bones and
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teeth to ours he seemed to be about 14
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years old but when dental specialist
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Chris Dean began to study his teeth he
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was in for a
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shock it turns out that all teeth fossil
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or not preserve a remarkably precise
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record of
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childhood this is a fossil tooth and we
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can see the enamel cap which covers the
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core of the tooth which is made of
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dentine uh dentine is just another word
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for Ivory and within the enamel you can
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see the rods which are running from the
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enamel denting Junction here out to the
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surface of the tooth
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enamel has a regular growth pattern like
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the rings of a
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tree under an electron microscope it
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looks like rods made of tiny beads each
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of the little beads along these prisms
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represent one day's growth because the
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cells which produce enamel are actually
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under the influence of a circadian or
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daily clock and those secretions during
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the day speed up and then slow down and
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there's a Perman record of that in every
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tooth so you can see rods running all
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the way through this tissue and every
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day along the rod there is a wobble
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where the tissue slows down and then
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speeds
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up so if you count the beads in these
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strings you can figure out exactly how
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many days that tooth has been
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growing when Chris looked at the
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fossilized teeth of tonoy he got a huge
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surprise turab boy wasn't 14 years old
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he was
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eight what that implies is that the
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growth of the T boy resembled more
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closely that of chimpanzees today to be
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5'3 at age 8 turab boy must have grown
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up very fast at a rate closer to chimps
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than
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us a chimp's childhood is short it is
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sexually mature at about 7
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human childhood is longer we reach
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puberty at about
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12 so as humans evolved from apes
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childhood was
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extended but what advantage could be
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gained by having helpless children
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around to feed and care for who take so
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long to grow
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up the mystery of prolonged childhood is
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at the heart of human evolution it may
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be related to brain size
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we humans have the biggest brains in the
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animal kingdom in relation to our body
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size they're so big that most of our
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brain growth has to happen outside the
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womb or our heads would never get
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through the birth
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canal a long slow childhood gives our
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brains time to grow after
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birth and time to learn everything we
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need to function in our complex Human
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Society
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ities that's the advantage of prolonged
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childhood for us at
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least but what about turab
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boy his brain was 900 cubic cm smaller
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than ours but more than twice as large
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as a
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chimps so was he on the way to thinking
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and Talking Like
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Us Ralph Holloway believes he was he's
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been collecting the brain endocasts of
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human ancestors for over 30
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years an endocast is a mold taken from
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the inside of the skull which reveals
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the shape of the brain Ralph is
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particularly interested in something
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called the broka area broka area is
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involved with memory functions executive
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functions but it does have a very
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important role to play in the motor
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aspects of
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speech in the brain of tur a boy Ralph
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believes he sees evidence for something
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remarkable a change in the brokas area
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tied to
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communication brokas caps regions on the
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turab boy are fully modern in terms of
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their appearance it is good solid
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evidence for the having the ability of
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symbolic Communication in other words
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language it's a controversial idea and
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we'll never know for sure if tur boy
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could speak but there are other Clues to
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his intelligence the stone tools he left
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behind Homo erectus made tools like this
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hand ax here it's been chipped
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extensively on both sides the point
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enables one to do piercing tasks the
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heavy bit here can be used from cracking
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bone or or chopping wood it's a very
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very versatile tool and a sharp one it
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may not look like much but the stone
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hand axe marks the birth of Technology
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Homo erectus has left us many signs of
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his
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inventiveness here in central Kenia Rick
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pots has been studying a treasure Trove
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of homo erectus Stone
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tool stone tools represented a momentous
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change because once you had Tools in
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your hands all the foods in the world
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could open up to you that represented a
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tremendous survival advantage
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here is a cache of over 500 stone hand
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axes made by Homo erectus just a mile
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away Rick visits the Quarry where for
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thousands of years these ancestors came
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to shape Stone into tools leaving behind
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unused fragments in the crevices at my
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feet there were thousands of fragments
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of Stone from Tool making and there were
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several scars where Homo rectus struck
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huge flakes
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we also see evidence that they could
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recognize flaws they could see which
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ones would break if they took them away
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so they simply discarded them here
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what's amazing about that is you could
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imagine an early homoerectus sitting
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right here making
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decisions the kind of decisionmaking it
00:18:47
takes to create a stone tool has been
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researched extensively by John
00:18:53
Shay I'm just going to tap it a little
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bit I'm just checking it out to see if
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there's any any internal flow pause
00:18:59
before I do it there might be one in
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here it feels like there might be
00:19:02
something in there but I like a
00:19:04
challenge so I'll map it
00:19:06
anyway even for an expert making a hand
00:19:09
ax is not easy yeah there's a flaw but
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we got around it a good tool maker has
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to understand the properties of stone to
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make this thing nice and thin easier to
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carry easier to transport and more of
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the sharp Cutting Edge I'm going to do
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something kind of counterintuitive I'm
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going to dull The Edge so that the next
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time I strike it it won't fail until I
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have a lot of pressure on it until I've
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hit it really hard the fracture will go
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much further than otherwise would so the
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home erectus did this tells us they were
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capable of thinking ahead of planning
00:19:41
the consequences of their actions so
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let's have a look here what'll this what
00:19:44
will happen here many of these stones
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have hidden defects failing to spot them
00:19:49
could spell disaster there's still a
00:19:51
flaw in there I can hear it I can tell
00:19:54
you see this it's right there now I've
00:19:57
worked around it but if I were an early
00:19:59
human and spotted this I would stop
00:20:01
making the hand ax right now if I'm out
00:20:03
running around the savanas chasing a
00:20:05
rhinoceros and you know or butchering a
00:20:07
rhinoceros as the lions are circling and
00:20:08
my handaxe breaks I'm in trouble so you
00:20:11
know I go home tonight I'm still going
00:20:12
to get fed even though I didn't make a
00:20:13
perfect handaxe as Homo rectus I might
00:20:16
end up being the meal instead you
00:20:19
know a skilled Craftsman Homo erectus
00:20:23
had evolved a new type of
00:20:27
intelligence but his big brain came with
00:20:30
hidden
00:20:31
costs modern brains consume 25% of our
00:20:35
body's energy our brain happens to be
00:20:38
the hungriest organ in the body and in
00:20:40
order to support a brain our size we
00:20:42
need lots of
00:20:43
calories with his big brain and body a
00:20:46
homo erectus like tab boy needed more
00:20:50
nutrition from his Savannah
00:20:52
environment T boy had he grown to
00:20:55
adulthood would probably stood around 6
00:20:57
feet tall this is a big strong creature
00:20:59
that would have had a huge energy
00:21:01
budget one can satisfy an energy budget
00:21:03
like that by eating plants but you have
00:21:06
to eat a lot a lot
00:21:08
plants but there's one food that can
00:21:10
supply the nutrients a growing brain and
00:21:13
body need and Africa was filled with it
00:21:17
the one highquality resource that's
00:21:19
probably most important for the
00:21:20
evolution of the genus homo is meat and
00:21:23
meat Bri products such as brain and
00:21:25
Marrow and fat they're high in protein
00:21:28
they're high in calories and they're
00:21:29
easy to digest but the one problem with
00:21:32
getting meat is that it's hard to get
00:21:35
most Predators rely on strength or speed
00:21:38
to kill their prey our ancestors had
00:21:42
neither today we are on top of the food
00:21:45
chain so it's hard to imagine the
00:21:48
predicament of those early
00:21:51
humans here was a slow moving creature
00:21:54
with no claws or fangs easy prey for the
00:21:58
hry Predators around
00:22:02
him this is a fossil forehead and brow
00:22:05
Ridge of a
00:22:07
homoerectus and on the brow Ridge you
00:22:09
can see the bite mark of a carnivore
00:22:12
well this reminds us that these
00:22:14
homoerectus individuals weren't at the
00:22:17
top of the food
00:22:18
chain so how did turab boy a weakling
00:22:22
with a big brain which needed calories
00:22:25
get his meat homus based problem how do
00:22:29
you kill a big dangerous animal that has
00:22:31
lots of meat and fat in it without that
00:22:33
animal also killing you I think the
00:22:35
answer to that was a very clever set of
00:22:38
Innovations and that is endurance
00:22:40
running and high activity in the middle
00:22:42
of the
00:22:44
day the ancestors of homo erectus small
00:22:48
hairy Apes like Lucy were bipedal but
00:22:52
probably didn't do much
00:22:54
running but turab boy kind were built to
00:22:57
run like
00:23:00
us this an accelerometer Dan liberman
00:23:03
believes they could run long distances
00:23:06
because like us they had lost their
00:23:08
thick coat of body hair and could keep
00:23:11
Cool by sweating not on this was the key
00:23:14
to their
00:23:16
success but how do we know if these
00:23:19
crucial changes go back all the way to
00:23:22
TOA boy's time over a million years
00:23:25
ago skin and hair are rarely preserved
00:23:29
in the fossil record so to find out we
00:23:32
have to look to a creature that's been
00:23:34
intimately connected with hair for a
00:23:36
long time the Lous all animals seem to
00:23:40
have some type of lice to parasitize
00:23:42
them mammals have them birds have them
00:23:45
even fish to have types of lice but most
00:23:48
other creatures have only one type of
00:23:49
lice that parasitize them humans have
00:23:52
one kind of Lous on their heads and
00:23:55
another in the pubic area geneticists
00:23:58
Mark ston King asked himself why the
00:24:01
answer that seems obvious is that when
00:24:03
we had body hair all over our bodies we
00:24:06
had one type of lice then we became
00:24:08
hairless until we only had hair on our
00:24:10
heads and in our pubic region and so
00:24:12
therefore you would have this hairless
00:24:14
Geographic barrier to contact between
00:24:16
the
00:24:17
two Mark was surprised to find out that
00:24:20
the human pubic louse is very different
00:24:23
from the human head louse somehow in the
00:24:26
past it seems to have come from from
00:24:29
gorillas because the pubic lice that is
00:24:31
actually more closely related to gorilla
00:24:33
lice now how it is our ancestors got
00:24:35
pubic lice from gorillas I wouldn't care
00:24:38
to
00:24:40
speculate nonetheless one needs gorilla
00:24:42
Li in order to really work this whole
00:24:44
thing
00:24:46
out the most likely scenario is that
00:24:49
when we lost our body hair the original
00:24:52
human Lae migrated to our heads leaving
00:24:56
the pubic area temporarily unpopulated
00:24:59
by lice when our ancestors had contact
00:25:03
with gorillas perhaps sleeping in their
00:25:05
nests were Scavenging their bodies for
00:25:08
meat the gorilla Lae colonized their
00:25:11
pubic region eventually it turned into
00:25:15
the human pubic louse of
00:25:18
today so if we could find out when the
00:25:21
human pubic louse and the gorilla louse
00:25:24
diverged we would have a rough idea of
00:25:27
when we lost our body
00:25:29
hair fortunately there's a way to figure
00:25:32
that out the genetic dating technique
00:25:35
known as the molecular
00:25:38
clock it's based on the fact that the
00:25:41
sequence of chemical bases which make up
00:25:44
DNA mutate at a regular rate it's just a
00:25:48
very simple idea that the rate of change
00:25:51
in DNA sequences is more or less
00:25:53
constant over time and that means that
00:25:56
you have a way of determining when two
00:25:59
species last shared a common
00:26:01
ancestor by counting the number of
00:26:04
differences in the genetic code of two
00:26:06
species scientists can determine how
00:26:09
long they've been evolving away from
00:26:11
each other when Mark used the molecular
00:26:14
clock to count the differences between
00:26:16
the DNA of gorilla lice and human pubic
00:26:20
lice he came up with a date for their
00:26:23
Divergence the estimated date for the
00:26:25
Divergence is roughly 3 million years
00:26:29
that means long before turab boy maybe
00:26:32
even around Lucy's time our ancestors
00:26:36
had slowly begun to lose their body
00:26:40
hair turab boy was mostly hairless just
00:26:44
like
00:26:47
us and that may be what gave him an edge
00:26:51
over other
00:26:53
Predators most animals are at a
00:26:55
disadvantage in the midday Sun because
00:26:58
they overheat they can only cool down by
00:27:02
panting and when they run fast they
00:27:05
can't pant that means they can only run
00:27:08
in short
00:27:10
Sprints quad pets can get out for about
00:27:13
10 to 15 minutes and then they overheat
00:27:15
but hominids can cool down by sweating
00:27:19
they use their entire body like like a
00:27:20
dog's
00:27:22
tongue our hairless bodies allow air to
00:27:25
circulate freely on our skin and cool us
00:27:28
down as sweat evaporates this makes us
00:27:31
one of the best longdistance runners in
00:27:34
the animal
00:27:35
kingdom Dan liberman believes this gave
00:27:38
our ancestors the ability to hunt in a
00:27:41
very unusual way it's called persistence
00:27:46
[Music]
00:27:48
hunting and he believes the modern
00:27:50
ethnographic record can show us how it
00:27:53
was
00:27:56
done the Bushmen of the Kalahari offer
00:27:59
us an insight into how Homo erectus
00:28:03
might have hunted 2 million years
00:28:06
ago the Bushmen know that at midday
00:28:10
animals rest in the shade which is why
00:28:12
it's the perfect time to be
00:28:15
hunting once they locate their prey in
00:28:18
this case audu the marathon begins
00:28:28
their strategy is simple run it to
00:28:33
exhaustion every time the animal tries
00:28:36
to rest the hunters track it down and
00:28:39
get it moving again they never give it a
00:28:42
chance to cool
00:28:43
down and the reason they can keep going
00:28:47
is that they can
00:28:51
sweat so if the theory is right the
00:28:54
Bushman hunt may help explain how taboy
00:28:58
got his
00:29:01
meat Homo erectus had come up with an
00:29:04
Innovative way of feeding his hungry
00:29:07
[Music]
00:29:12
brain in this modern hunt the Bushmen
00:29:15
ran in the fierce heat for over 4
00:29:19
hours the kudu was finally immobilized
00:29:23
by heat
00:29:26
stroke tur boy wouldn't have had steel
00:29:29
tipped Spears like the Bushman but he
00:29:32
wouldn't have needed
00:29:36
them homore is probably hunted with
00:29:39
Close Quarters weapons with Spears that
00:29:40
were thrown at animals from a short
00:29:42
distance clubs thrown rocks weapons like
00:29:45
that they weren't using longdistance
00:29:47
projectile weapons that we know
00:29:49
[Music]
00:29:51
of the homo erectus hunt was simple but
00:29:56
effective it fed not just their larger
00:29:59
brains but the growing complexity of
00:30:02
that early human
00:30:07
society there are other social animals
00:30:11
but none quite like
00:30:13
[Music]
00:30:16
us Society is in every corner of our
00:30:20
lives our relationships communication
00:30:24
rules symbolism all the things that bind
00:30:27
us
00:30:29
together what's behind it why do we
00:30:32
become so
00:30:35
social could it have something to do
00:30:37
with another
00:30:39
Innovation something unprecedented in
00:30:42
our
00:30:43
Evolution building fires and
00:30:47
cooking here we got erectus the first
00:30:49
species that looks like us and I think
00:30:52
only cooking can explain the magnitude
00:30:54
of this
00:30:56
change the earliest evidence that our
00:30:58
ancestors deliberately used fire for
00:31:01
cooking dates to long after taby's
00:31:05
time but Richard rangam is sure Homo
00:31:08
erectus was building fires much
00:31:13
earlier now for the first time we had a
00:31:15
species that was committed to living on
00:31:17
the ground because they lose their
00:31:19
climbing
00:31:20
adaptations well how were they sleeping
00:31:24
they had to be able to protect
00:31:25
themselves from wild animals on the
00:31:28
African Savannah full of predators who
00:31:30
hunt by Night Richard believes turab boy
00:31:34
and his people couldn't have survived
00:31:37
Without
00:31:38
fire and he thinks only cooking which
00:31:41
makes food more soft and digestible can
00:31:44
explain why Homo erectus evolves smaller
00:31:47
teeth and a much smaller gut these
00:31:51
things are compatible with the reduced
00:31:53
cost of digestion produced by cooking
00:31:55
food nothing else is as our ancestors
00:31:59
reaped the benefits of cooking something
00:32:01
else happened too at least according to
00:32:05
Rum we became more social humans have
00:32:09
this wonderfully calm temperament
00:32:11
compared to chimpanzees say where did it
00:32:14
come from we were drawn to a common
00:32:17
place the
00:32:19
fireplace rum believes we learned to
00:32:21
share and
00:32:23
communicate sitting around fires waiting
00:32:26
for food to cook
00:32:29
look it's speculative but one thing is
00:32:32
for sure in the homo erectus World new
00:32:36
social relationships had to be
00:32:39
evolving the bonds between mothers and
00:32:42
children must have been very different
00:32:44
from the
00:32:47
Apes for example a mother aratan will
00:32:51
not allow any other individual to take
00:32:54
her infant will be in constant SK skin
00:32:58
to- skin contact with that baby for at
00:33:00
least the first 6 months of life not a
00:33:03
moment out of contact secure in this
00:33:06
unbreakable mother infant Bond ape
00:33:09
babies need less capacity to read the
00:33:11
intentions of others than human
00:33:14
babies whose bond with their mothers is
00:33:17
surprisingly less
00:33:19
secure the shocking fact is that human
00:33:23
mothers abandon their infants much more
00:33:25
often than eight mothers infanticide by
00:33:29
a mother is more common among humans
00:33:32
than any other higher ape maternal
00:33:35
commitment is a lot more contingent in
00:33:37
humans than it seems to be in other Apes
00:33:41
unlike most primates human mothers share
00:33:44
parenting with
00:33:46
others a child's survival can depend on
00:33:49
making itself appealing to a number of
00:33:53
caregivers perhaps that's why human
00:33:56
infants have evolved a uniquely acute
00:34:00
sensitivity human infants are born
00:34:03
connoisseurs of mothers reading her
00:34:06
facial expression looking for signs of
00:34:12
commitment we are born hardwired with an
00:34:15
awareness of the intentions and emotions
00:34:17
of others which is unique in the animal
00:34:22
world when did humans develop this gift
00:34:26
for a attributing mental States and
00:34:29
feelings to others and for caring about
00:34:32
what others thought about
00:34:34
them could these social instincts have
00:34:37
developed with Homo erectus along with
00:34:41
Cooperative hunting bigger brains longer
00:34:44
childhoods and the use of
00:34:48
fire perhaps toab boy and his people
00:34:51
already had social skills that would be
00:34:54
familiar to
00:34:56
us here were intelligent social beings
00:35:00
with an increasing capacity for
00:35:06
cooperation it may be this that made
00:35:09
possible another great achievement The
00:35:11
Exodus from
00:35:14
Africa for millions of years our
00:35:17
earliest ancestors stayed on the African
00:35:20
savanas but at some point they started
00:35:23
to
00:35:25
leave ancient fossil skulls and tools
00:35:29
have been found as far away as China and
00:35:33
Indonesia the question is when did they
00:35:36
leave Africa and
00:35:39
why when turab boy was found scientists
00:35:43
thought they had the
00:35:44
answer here was a strong large-brained
00:35:48
ancestor capable of an arduous
00:35:51
migration he had the look of a World
00:35:54
Conqueror in the mid 1980s we were
00:35:58
thinking that a homid like this one had
00:36:00
left Africa but had done it maybe about
00:36:02
a million years
00:36:04
ago for decades scientists believed big
00:36:08
strapping humans like turab boy left
00:36:11
Africa a million years ago but new
00:36:14
discoveries are showing the migration
00:36:17
may have started a lot earlier than
00:36:21
that dimini
00:36:24
Georgia the mountains and plains of the
00:36:26
caucuses thousands of miles from the
00:36:29
Great Rift Valley had never produced any
00:36:32
fossils of early human
00:36:36
ancestors but then an astonishing
00:36:39
Discovery was
00:36:45
made it was a lower jaw with teeth
00:36:48
downward this way in the
00:36:51
ground so when I started to clean those
00:36:54
front teeth came to light it became
00:36:57
obvious to me that we had found some
00:36:59
kind of
00:37:01
homade but what
00:37:04
kind the jaw seemed to be a primitive
00:37:07
form of homo
00:37:08
erectus but at first hardly anyone
00:37:11
believed
00:37:13
it in 91 when we found this
00:37:16
jaw this was lot of scientists were
00:37:20
quite skeptical about it was it was very
00:37:23
hard to imagine Georgia Caucasus to be
00:37:26
on the map of the human
00:37:29
evolution since then demoni has been put
00:37:32
on the map of human evolution in a big
00:37:35
way the site has turned up a treasure
00:37:38
Trove of homo erectus
00:37:41
fossils they've transformed our
00:37:43
understanding of who left Africa and
00:37:47
when they showed that the first humans
00:37:49
to leave Africa were much more primitive
00:37:52
than turab boy people thought that the
00:37:55
homins that left Africa were very tall
00:37:59
like turab boy with big Brands advanced
00:38:02
technology and the Mani proved the the
00:38:05
opposite at 4 and 1/2 ft tall they were
00:38:09
smaller than turab
00:38:11
boy with more aplike shoulders and a
00:38:14
simple stone technology they are much
00:38:17
more primitive they have small brains
00:38:20
and same time they were using very
00:38:23
primitive stone
00:38:25
tools the next surprise came when they
00:38:27
dated the
00:38:29
site the ancient dimini landscape has
00:38:32
been built up layer by layer over
00:38:35
millions of
00:38:37
years 1.81 million years ago massive
00:38:42
volcanic eruptions deposited a layer of
00:38:46
Ash the fossils sat on top of this ash
00:38:49
so must have been slightly younger
00:38:52
around 1.8 million years
00:38:56
old to the vast majority of scientists
00:38:59
who believe that all our ancestors
00:39:01
evolved in Africa this was a stunning
00:39:05
surprise how had a small primitive Homo
00:39:08
erectus migrated to the Caucasus almost
00:39:11
2 million years ago long before toab
00:39:16
boy scientists now accept that as soon
00:39:19
as Homo erectus appeared on the savanas
00:39:21
of Africa they started to
00:39:25
leave suddenly with the origin of
00:39:27
erectus we get this shift in body shape
00:39:30
and then boom They're Out of Africa
00:39:32
right
00:39:33
away the Georgia fossils proved that
00:39:36
homo erectus left Africa much earlier
00:39:39
than previously thought an even more
00:39:42
provocative find shows the migration may
00:39:45
have started even
00:39:48
earlier 5,000 m from
00:39:53
Africa the island of Flores Indonesia
00:39:59
in 2003 researchers made a discovery so
00:40:02
strange nobody knew what to make of
00:40:06
it they found the bones of a tiny human
00:40:09
ancestor just over 3 ft tall even
00:40:13
smaller than the dimini fossils they
00:40:17
called this baffling new ancestor homo
00:40:21
floresiensis and because of its tiny
00:40:23
size nicknamed it The Hobbit
00:40:29
this has created a tremendous amount of
00:40:31
grief because we're not really sure of
00:40:33
what we're seeing here uh the size of
00:40:36
the hoppit brain endocast is roughly 400
00:40:41
CC's that's barely bigger than the brain
00:40:44
of Lucy the famous bipedal Ape from 3
00:40:47
million years
00:40:51
ago it's not just a small brain and A
00:40:54
Primitive looking face but the foot's
00:40:55
primitive the hands primitive the leg is
00:40:57
primitive the lower limb is very much
00:40:59
like the Lucy skeleton that was a big
00:41:04
surprise and in the cave where this
00:41:06
primitive creature was found they also
00:41:09
uncovered stone tools something Lucy
00:41:12
never
00:41:13
had people have for a long time said
00:41:16
well you need a big brain to make stone
00:41:17
tools uh well okay homop Anis is making
00:41:20
stone tools this creature has the brain
00:41:21
the size of an orange clearly that
00:41:23
equation's
00:41:25
gone everything about these creatures is
00:41:28
an
00:41:29
enigma where did they come from and what
00:41:32
were they some researchers have argued
00:41:35
that floresiensis is just a dwarfed
00:41:38
population of modern people that
00:41:40
suffered some kind of disease that
00:41:42
caused them to both dwarf and have
00:41:44
relatively small
00:41:46
brains but when scientists took a closer
00:41:49
look most saw no evidence of
00:41:52
disease the stone tools and the shape of
00:41:55
the face moved the focus to to our old
00:41:57
friend Homo
00:41:59
erectus some researchers think that
00:42:02
homofloriensis evolved from Homo
00:42:05
erectus but how did they get so
00:42:08
small something called Island dwarfism
00:42:12
may be the
00:42:13
answer isolated on islands with limited
00:42:16
food large mammals sometimes shrink over
00:42:20
time on flues there were once pygmy
00:42:24
elephants the size of cows
00:42:28
could the same evolutionary pressure
00:42:30
have acted on Homo erectus to produce
00:42:33
The
00:42:34
Hobbit or was this mysterious creature
00:42:37
descended from an even more primitive
00:42:40
ancestor so perhaps we're sampling a
00:42:43
period which is at the very beginning of
00:42:46
the homo
00:42:47
lineage so whatever The Hobbit was
00:42:51
perhaps its ancestors were the very
00:42:53
first wave of migration Out of Africa
00:42:57
some unknown creature part bipedal AP
00:43:00
like Lucy and part Homo
00:43:04
[Music]
00:43:08
erectus so if that's the case then what
00:43:11
we see in Indonesia makes sense it's
00:43:14
kind of a body that existed before human
00:43:17
bodies became more
00:43:19
[Music]
00:43:21
modern what would push such primitive
00:43:24
creatures out of Africa
00:43:32
a key driving force behind the migration
00:43:35
was probably a climate
00:43:37
shift which spread grasslands from
00:43:40
Africa into
00:43:42
[Music]
00:43:45
Asia and with the grasses went the game
00:43:50
animals animals are going to be moving
00:43:52
out of Africa and the hominids will just
00:43:54
be keeping Pace with those animals after
00:43:56
all that's their livelihood
00:43:58
of course our ancestors didn't know they
00:44:00
were leaving Africa they just followed
00:44:03
the animals they depended on through the
00:44:06
canani up into the Middle East and
00:44:10
Beyond it's often been called an exodus
00:44:14
but it really wasn't like that when
00:44:17
people think of Exodus they think of the
00:44:18
Bible or they think of migration they
00:44:20
think of Europeans coming over here to
00:44:21
the new world it probably wasn't like
00:44:24
any historical migration this this
00:44:27
dispersal of humans Out of
00:44:29
Africa the process was probably very
00:44:33
very
00:44:34
slow much like the spread of any other
00:44:36
animal species into new
00:44:39
territories you could imagine a group of
00:44:42
homo erectus moving their range a
00:44:45
kilometer a year in One Direction and
00:44:48
doing that continually over a long
00:44:51
enough period of time you can get the
00:44:53
distance from Africa to Indonesia
00:44:56
covered in and say 15,000
00:45:00
years by a million years ago our
00:45:03
ancestors had populated Asia from the
00:45:06
caucuses to
00:45:10
Indonesia and they were in Europe too as
00:45:13
a recent discovery in Spain has
00:45:15
[Music]
00:45:16
shown Homo erectus had conquered the old
00:45:25
world the fact that they made it so far
00:45:28
with limited technology and relatively
00:45:31
small brains makes them seem even more
00:45:37
remarkable and their longevity was
00:45:40
astonishing a few pockets of homo
00:45:42
erectus may have been still Clinging On
00:45:45
in Asia just 50,000 years ago that's a
00:45:49
span of two million
00:45:53
years our own species has only been
00:45:56
around for
00:46:00
200,000 what was the secret of homo
00:46:02
erectus
00:46:04
[Music]
00:46:06
success the amazing finds at dimini have
00:46:09
given us one last
00:46:11
clue one of the skulls belonged to an
00:46:14
old man his Jawbone revealed he had lost
00:46:18
all his teeth well before he died that
00:46:21
was a real surprise it means that this
00:46:24
individual survived 2 years without
00:46:28
teeth for an elder to have survived that
00:46:31
long without teeth must mean that others
00:46:34
in the group were feeding him perhaps
00:46:37
even chewing his food for him I love
00:46:41
this story this was a remarkable
00:46:44
testimony from the past about the
00:46:46
quality of emotional life that may have
00:46:50
characterized Homo
00:46:52
erectus here is a tantalizing clue to
00:46:55
what may be this ancestors most
00:46:58
important
00:46:59
Legacy the instinct to look after each
00:47:05
other and it helps us imagine tab boy's
00:47:08
final day on
00:47:10
[Music]
00:47:15
Earth in the animator's scenario he
00:47:18
starts the day out on a
00:47:23
hunt but he has trouble keeping up with
00:47:25
the hunting party
00:47:30
why the evidence from his skeleton is
00:47:33
that he was sick and in pain at the time
00:47:35
he
00:47:36
died if we look at his lower jaw we can
00:47:39
see right here under the teeth that
00:47:42
we've got a bit of an abscess and an
00:47:44
infection that kind of an infection
00:47:47
could have entered the rest of his body
00:47:48
could have killed him an abscess that
00:47:51
ate away that much of his Jawbone would
00:47:53
have been agonizing
00:47:57
turab boy is in so much pain he's unable
00:48:01
to continue the
00:48:04
hunt knowing he would be looked after
00:48:08
perhaps he returned to his campsite to
00:48:10
find Comfort among the
00:48:13
females I think he was probably a
00:48:15
miserable fellow um in a lot of pain and
00:48:18
very dependent on on support and
00:48:22
handouts so it was a species that
00:48:24
already felt that his one of our
00:48:26
weaklings that you know we love and must
00:48:29
must protect and care for to have got
00:48:30
him that
00:48:32
far but however much they may have
00:48:35
wanted to help him there was nothing
00:48:37
they could do about the infection that
00:48:40
was probably spreading through his
00:48:42
[Music]
00:48:45
body from what the evidence suggests I
00:48:48
just always imagined him not knowing
00:48:51
what was wrong with him and there's a
00:48:54
sadness to it but all ultimately from
00:48:57
that comes this Immortal
00:49:02
being his skeleton was so complete it is
00:49:06
likely he died in water which would have
00:49:09
protected
00:49:10
[Music]
00:49:14
him it's very unusual to get a skeleton
00:49:17
because normally these things are eaten
00:49:18
by Carnival and in this case it seems
00:49:21
that the boy's body was washed into a
00:49:23
swamp and so the carnivals never saw it
00:49:25
and never destroyed it and it gradually
00:49:28
decomposed and as the rivers flooded
00:49:30
brought in more sediment buried it and
00:49:33
you could see Footprints of hippos that
00:49:35
had walked all over the bones and and
00:49:37
some of the ribs and things were
00:49:39
standing vertically instead of lying
00:49:40
flat on the ground and you could sort of
00:49:43
reconstruct the situation and how what
00:49:45
boy what had happened after he died and
00:49:47
and why he was complete it was just it
00:49:49
really was it was amazing experience to
00:49:52
see
00:49:55
it for almost 2 million years his bones
00:49:59
were preserved by the Earth their
00:50:02
Discovery opened a window for us on an
00:50:05
unknown
00:50:07
world the world of the most successful
00:50:10
human ancestor of all
00:50:12
time Homo
00:50:14
[Music]
00:50:16
erectus they've revealed to us that
00:50:19
mysterious moment when almost everything
00:50:22
human was born our bodies Our Minds our
00:50:30
emotions think of all we've
00:50:34
[Music]
00:50:38
become trace the threads of our Origins
00:50:41
through the ancestors who went before
00:50:44
they all lead back to taboy and His Kind
00:50:48
the first humans
00:50:51
[Music]
00:51:01
Nova's got a brand new Evolution website
00:51:04
with lots to explore about our ancestors
00:51:07
we want to know what you think bookmark
00:51:09
it today and give us your feedback find
00:51:12
it at
00:51:15
pbs.org for millions of years our
00:51:18
ancestors shared the planet with other
00:51:20
human
00:51:21
species why were we the sole survivors
00:51:25
could the fate of the neander hold the
00:51:27
key this is one of the main goals of
00:51:30
sequencing the nandal genome
00:51:33
groundbreaking evidence tells a new
00:51:34
story of human evolution our story part
00:51:38
three of becoming human last human
00:51:40
standing next time on Nova
00:51:51
[Music]
00:52:08
this Nova program is available on DVD
00:52:10
and Blu-ray at shop
00:52:12
pbs.org or call 1 1800 playay PBS
00:52:17
[Music]
00:52:33
[Music]