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Pegasus, Bucephalus, Champion,
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Trigger, Seabiscuit, Red Rum.
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I'm talking about the stuff
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of myth and legend.
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Just look at her.
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She's absolutely
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gorgeous, aren't you?
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Equus ferus caballus - the horse, to
you and I.
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A statuesque pinnacle
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of natural art.
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This is a creature
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supremely shaped to move.
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Thanks to 700 mighty muscles...
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..and a heart the size of a
football...
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..the horse is one of the fastest
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and most powerful animals on the
planet.
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They don't call it horsepower for
nothing.
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So how did the horse
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become one of nature's
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greatest athletes?
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To answer that...
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..we must travel back in time...
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..to meet the key
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movers and shakers...
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..before hooves thundered...
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..or hearts raced.
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Back to a time
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when almost nothing at all
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moved.
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The story of the horse
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and, in fact, the story of movement
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can be traced, incredibly,
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right to our own doorstep.
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This is a quintessential
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English landscape, a rural idyll of
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rolling hills and ancient woodlands.
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But I've got to tell you
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that I was standing here just over
half a billion years ago,
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the view would have been very
different. In fact, I wouldn't
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have been standing, I'd have been
submerged deep beneath the waves
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on the ocean floor. And over millions
of years,
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these rocks have been pushed up and
laid bare.
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And they tell us of the history of
that time,
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a history written in sand and silt.
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A history with some fascinating clues.
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Hiding in plain sight
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are some of the most precious
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fossils on the planet.
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But millions of years of weathering
have warped these rocks,
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making them very hard to spot.
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Now, I did tell you they were tricky
to see,
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but there is one right in front of me
here.
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Just follow my fingers.
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It starts up here,
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then it arches down.
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You can see the ridges in the rock,
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particularly visible here.
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And then it comes up towards
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my shoulder, and this bit follows
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right up past my ear.
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These would have been made by fronds
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and they would have been attached
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around a centre point, which
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could have been somewhere here.
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This is a fossil of Bradgatia.
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And I know it doesn't look like much,
it might look like
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an old cabbage that's been pressed in
the rock to you,
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but it wasn't an old cabbage.
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It wasn't a plant at all.
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And this is a very, very important
fossil
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because it's a fossil of one of the
earliest animals
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that ever lived on Earth.
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Over half a billion years ago,
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this slab of rock...
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..was home to some of the very first
animals.
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Theirs is a peaceful life.
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But this strange community
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does have a problem.
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When animals with large, complex
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bodies first evolved,
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they couldn't move.
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We call them sessile.
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Rooted to the ground,
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they must rely on the ocean
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to bring them what they need...
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..and they're powerless
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if it doesn't.
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Animal life could have remained
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stuck in this way forever,
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if it wasn't for an evolutionary
maverick.
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This is a cast of a fossil that's
about 565 million years old,
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which means it formed around the same
time as Bradgatia. Now,
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when the scientists first looked at
it, they were initially confused.
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It's quite difficult to see.
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Look, it starts up here and it runs
down here.
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It's almost as if someone has been
running their fingertip
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over some soft mud,
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and then it terminates down here.
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But if you look here,
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you can see there are a few little
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half-moon shapes. Now, the reason
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those scientists were initially
confused is they were probably
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looking for a fossil of an animal, but
this is not that.
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What it is is a fossil of something
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an animal left behind.
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Now, we think the story goes something
like this.
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In amongst the creatures stuck to the
seabed is a tiny animal,
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little more than a gelatinous blob.
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Like other animals here,
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it eats specks of food
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that drift on the ocean currents.
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But today, the current has shifted...
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..and is now carrying the meagre
morsels just out of reach.
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Deprived of food, the only option
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for this stationary population
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is to sit and wait for their luck
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and the currents to change.
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But this animal is a pioneer.
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You see, this little blob
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can do something
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that the other animals can't.
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Abandon the safety of its home...
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..and move.
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With every heave...
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..it leaves a mark.
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Some of the earliest animal tracks on
the planet.
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One small step for this tiny blob,
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one giant leap for animalkind.
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Now, we'll never know exactly when the
first step was taken.
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We can presume that there were some
missteps -
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evolutionary stumbles, if you like -
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but that leap between being sessile
and motile was a profound one.
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Today...
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..whether they are finding food...
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..or mates...
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..or shelter...
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..our planet is an extravaganza
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of motion.
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An estimated 97% of animals
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moving in weird and wonderful ways.
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00:10:06,880 --> 00:10:09,080
And none of this would be possible
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without one key ingredient.
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Muscle.
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HORSES WHINNY
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To understand just how powerful muscle
can be,
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we need a demonstration from an
expert.
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I give you...the leech.
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I know, not everyone's favourite
animal,
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but it won't surprise you to know
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that I'm rather a fan of the leech.
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What are they?
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Well, they're a type of worm,
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and there are about 700 species
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in the world.
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Many, like this one, are parasitic.
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This is a medicinal leech,
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and it's been used by
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medical practitioners
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to suck the blood from humans for
3,500 years.
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00:11:07,600 --> 00:11:09,200
But I digress.
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What about its movement?
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Well, let's take a look at their body.
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First thing you'll notice - no legs.
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Its body is made up almost
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entirely of muscles.
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Muscles are built from tiny cells
called myocytes.
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We sometimes call them muscle fibres.
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Within the leech,
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there are thousands,
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while an animal like the horse
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contains millions
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and millions of them.
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They work thanks to their superpower -
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their ability to contract.
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Now, this leech's muscle cells
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are arranged in opposing sets.
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There are circular muscles
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that run around its body
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and longitudinal muscles,
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which run from one end to the other.
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So how exactly does it move? Well,
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I'll try and demonstrate that here.
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Come on.
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It stretches forward
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using those circular muscles,
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and then contracts its longitudinal
muscles
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and pulls itself forward...
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..so that it can slowly inch across
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the palm of my hand
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and down my fingers.
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Something that I find
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quite therapeutic.
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You may consider it perverse,
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but I'm rather enjoying this.
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Today, it's easy to take muscles for
granted...
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..but half a billion years ago,
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it was primitive muscle cells
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that turned contraction
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into action...
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..allowing pioneering animals
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to take a leap into the unknown.
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And the importance of this
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simply can't be underestimated,
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because from this point on, movement
would become
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one of the most powerful driving
forces in animal evolution.
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To reach the next step in the story of
the horse,
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we must hit fast-forward.
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For the next 40 million years,
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evolution gallops on.
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THUNDERCLAP
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Muscles stretch
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and shape animal life,
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and more and more time is spent...
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..on the go.
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As they say, necessity is the mother
of invention,
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and that was certainly the case for
animals experimenting
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with early locomotion.
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Down here, every trip across
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the seafloor demands energy,
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and lots of it.
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And to get from A to B,
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it's thought that ancestors of the
horse had evolved to use muscle
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in a totally new way. Incredibly,
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evidence of this
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00:15:13,880 --> 00:15:16,800
can still be seen today.
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Inside this little plastic tub here,
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I have a beautiful animal.
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It's called a sea squirt, or a
tunicate,
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and it's a chordate, which means we're
actually related to this.
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I know it's difficult to believe, but
it's true.
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And the benefit of looking at this
particular species
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is that it's transparent.
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I can see inside it.
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And I can see a tube running around
its body,
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00:15:46,160 --> 00:15:48,600
and that tube is filled full of
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oxygen, minerals and sugar.
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It's its blood.
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And that tube is contracting.
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Waves of muscle contraction are
pushing that blood around the body.
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00:16:06,920 --> 00:16:08,960
Fundamentally,
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this is a simple heart.
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It's thought that systems like this
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allowed this ancestor of the horse
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to enjoy an active lifestyle.
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00:16:30,920 --> 00:16:33,200
Just like the rest of its kind,
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00:16:33,200 --> 00:16:34,960
nutrient-rich blood
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is being pumped through its body,
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making its muscles fizz with energy.
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Now, most of these creatures
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wouldn't win any races,
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00:16:49,560 --> 00:16:51,040
spending their energy just
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00:16:51,040 --> 00:16:53,640
wriggling along the seabed.
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But the ancestor of the horse
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seems to have had an extra boost,
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meaning...
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..it can swim harder, better,
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00:17:10,880 --> 00:17:13,080
faster, stronger.
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00:17:39,560 --> 00:17:42,360
Its remarkable athletic ability
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00:17:42,360 --> 00:17:46,120
is thanks to an innovative use of
muscle
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that unlocked the full potential of
the heart.
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00:17:58,840 --> 00:18:03,280
At this point, evolution all starts to
go a bit Frankenstein.
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You see, for any muscle to contract,
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00:18:05,440 --> 00:18:07,480
it requires a stimulus, an order,
264
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and that typically comes in the form
of a tiny electric zap.
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00:18:13,520 --> 00:18:15,120
And it's thought that some
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muscle cells inside some of
267
00:18:16,680 --> 00:18:19,480
the earliest hearts took charge,
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00:18:19,480 --> 00:18:22,520
specialised and started to send out
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00:18:22,520 --> 00:18:25,520
a series of rhythmic zaps.
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00:18:25,520 --> 00:18:29,280
And all of the surrounding muscle
cells complied by contracting,
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00:18:29,280 --> 00:18:33,280
generating a single powerful pulse.
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00:18:35,680 --> 00:18:38,360
Now, these mutant zapping cells
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are called pacemakers, and almost all
animals have them.
274
00:18:41,840 --> 00:18:46,840
We have a single primary pacemaker
called the sinoatrial node.
275
00:18:46,840 --> 00:18:51,720
And as soon as those ancient
pacemakers began to pulse,
276
00:18:51,720 --> 00:18:54,840
they instigated a revolution.
277
00:18:58,400 --> 00:19:01,280
In the ancestor of the horse,
278
00:19:01,280 --> 00:19:04,320
those specialised pacemaker cells
279
00:19:04,320 --> 00:19:06,160
have now clustered together
280
00:19:06,160 --> 00:19:07,960
in a localised region...
281
00:19:07,960 --> 00:19:09,680
HEARTBEAT
282
00:19:11,560 --> 00:19:13,120
..giving its heart
283
00:19:13,120 --> 00:19:15,080
a more powerful beat.
284
00:19:20,240 --> 00:19:22,920
And over many generations...
285
00:19:24,440 --> 00:19:26,920
..the beat gets stronger.
286
00:19:30,960 --> 00:19:34,000
The muscle walls around the pacemaker
thicken...
287
00:19:36,840 --> 00:19:38,320
..chambers form...
288
00:19:40,400 --> 00:19:41,760
..and valves...
289
00:19:42,920 --> 00:19:44,840
..directing blood flow
290
00:19:44,840 --> 00:19:46,640
around the body...
291
00:19:51,440 --> 00:19:53,920
..becoming an iconic,
292
00:19:53,920 --> 00:19:56,040
life-sustaining organ.
293
00:19:58,440 --> 00:20:01,640
It's an ingenious use of muscle,
294
00:20:01,640 --> 00:20:05,560
one that transformed animal
locomotion.
295
00:20:07,520 --> 00:20:11,160
When hearts went from being a simple
pump to a more complex
296
00:20:11,160 --> 00:20:12,840
muscular mechanism,
297
00:20:12,840 --> 00:20:17,320
it led to a step change in the
evolution of movement.
298
00:20:17,320 --> 00:20:21,080
It allowed animals to become bigger,
stronger, faster.
299
00:20:21,080 --> 00:20:25,440
It allowed them to get off of that
seabed into the world above.
300
00:20:25,440 --> 00:20:27,360
And from that point on,
301
00:20:27,360 --> 00:20:30,200
life would become a slithering,
302
00:20:30,200 --> 00:20:32,520
crawling, walking, running,
303
00:20:32,520 --> 00:20:35,600
jumping and climbing adventure.
304
00:20:35,600 --> 00:20:37,400
Today...
305
00:20:38,960 --> 00:20:41,520
..across the globe,
306
00:20:41,520 --> 00:20:43,520
beating hearts are pumping oxygen
307
00:20:43,520 --> 00:20:45,360
through all sorts of bodies.
308
00:20:48,320 --> 00:20:51,520
Around 2.5 billion heartbeats
309
00:20:51,520 --> 00:20:53,840
will supply your muscles with
310
00:20:53,840 --> 00:20:55,360
the energy they need...
311
00:20:56,920 --> 00:20:59,720
..from your first breath
312
00:20:59,720 --> 00:21:02,960
till your last.
313
00:21:04,840 --> 00:21:08,680
It's a rhythm that connects us all
314
00:21:08,680 --> 00:21:11,400
to the first beats,
315
00:21:11,400 --> 00:21:14,400
over half a billion years ago.
316
00:21:18,520 --> 00:21:21,280
Time to take a leap forward...
317
00:21:23,160 --> 00:21:25,360
..as the descendants of those
318
00:21:25,360 --> 00:21:27,320
early swimmers get bigger,
319
00:21:27,320 --> 00:21:29,640
stronger and faster.
320
00:21:31,040 --> 00:21:33,360
They shapeshift through countless
321
00:21:33,360 --> 00:21:35,200
iterations until
322
00:21:35,200 --> 00:21:39,000
140 million years later...
323
00:21:41,920 --> 00:21:43,280
..they have become...
324
00:21:44,680 --> 00:21:46,080
..fish.
325
00:21:51,240 --> 00:21:55,200
This is an ocean full of powerful
bodies.
326
00:21:57,240 --> 00:22:00,320
But here, it's not how many muscles
327
00:22:00,320 --> 00:22:02,800
you've got that counts,
328
00:22:02,800 --> 00:22:04,760
it's how you use them.
329
00:22:08,400 --> 00:22:10,480
Now, there are many forces
330
00:22:10,480 --> 00:22:12,320
shaping evolution.
331
00:22:14,080 --> 00:22:16,920
The need to find food, the need to
find mates.
332
00:22:19,080 --> 00:22:22,320
But there are even greater forces at
play,
333
00:22:22,320 --> 00:22:25,000
those forces which shape the entire
universe.
334
00:22:25,000 --> 00:22:28,920
I'm talking about the laws of physics.
335
00:22:28,920 --> 00:22:31,040
And when it comes to locomotion,
336
00:22:31,040 --> 00:22:33,760
harnessing these would be key.
337
00:22:33,760 --> 00:22:38,000
And fish have achieved that with a
remarkable innovation,
338
00:22:38,000 --> 00:22:40,800
something that's startling in its
simplicity,
339
00:22:40,800 --> 00:22:43,400
but significant in its importance.
340
00:22:48,080 --> 00:22:49,960
Something that, today,
341
00:22:49,960 --> 00:22:54,640
has helped make fish the success story
of our oceans.
342
00:22:57,880 --> 00:23:00,600
Attached to their streamlined bodies,
343
00:23:00,600 --> 00:23:02,960
structures of flesh, cartilage
344
00:23:02,960 --> 00:23:04,840
and bone have evolved.
345
00:23:06,800 --> 00:23:09,160
Tools which their muscles
346
00:23:09,160 --> 00:23:13,200
can control, expanding the mechanics
347
00:23:13,200 --> 00:23:15,360
of movement available to them.
348
00:23:18,360 --> 00:23:21,000
They can be gliders,
349
00:23:21,000 --> 00:23:22,560
thrusters,
350
00:23:22,560 --> 00:23:25,040
rudders.
351
00:23:25,040 --> 00:23:28,520
I'm talking about fins.
352
00:23:34,600 --> 00:23:38,280
And 380 million years ago,
353
00:23:38,280 --> 00:23:40,400
the ancestor of the horse
354
00:23:40,400 --> 00:23:43,840
was a fish, with fins like this.
355
00:23:46,480 --> 00:23:49,320
You can see the fin here.
356
00:23:49,320 --> 00:23:51,040
But look at the base.
357
00:23:51,040 --> 00:23:52,960
It's made up of a series of
358
00:23:52,960 --> 00:23:56,120
robust, strong bones which anchor it
to the body,
359
00:23:56,120 --> 00:23:59,640
and they would have been covered with
powerful muscles.
360
00:23:59,640 --> 00:24:02,080
And it's this stalk, or lobe,
361
00:24:02,080 --> 00:24:04,760
which gives this group of fishes their
name.
362
00:24:04,760 --> 00:24:08,240
We call them the lobe-finned fishes.
363
00:24:08,240 --> 00:24:11,440
Now, I've got to be honest with you,
in the open ocean,
364
00:24:11,440 --> 00:24:14,440
this set-up probably didn't confer
them with much of
365
00:24:14,440 --> 00:24:15,680
a competitive advantage,
366
00:24:15,680 --> 00:24:18,080
but under certain circumstances,
367
00:24:18,080 --> 00:24:20,960
it proved to be a real bonus.
368
00:24:30,320 --> 00:24:32,640
This is Onychodus...
369
00:24:34,360 --> 00:24:36,040
..an ancient predator
370
00:24:36,040 --> 00:24:37,840
as big as a crocodile...
371
00:24:39,960 --> 00:24:42,880
..with muscular lobed fins.
372
00:24:47,080 --> 00:24:49,080
Now, its size and weight
373
00:24:49,080 --> 00:24:51,240
should be an advantage,
374
00:24:51,240 --> 00:24:54,240
making Onychodus a formidable foe.
375
00:24:56,240 --> 00:24:57,840
But when it swims...
376
00:25:00,280 --> 00:25:03,240
..the water around it is churned up,
377
00:25:03,240 --> 00:25:05,120
giving the game away.
378
00:25:11,080 --> 00:25:14,440
So how does this ocean giant catch its
dinner?
379
00:25:20,880 --> 00:25:24,080
The answer lies in those lobed fins.
380
00:25:24,080 --> 00:25:27,240
Inside there is a tool that's just
begging to be used,
381
00:25:27,240 --> 00:25:30,200
a tool with enormous potential.
382
00:25:30,200 --> 00:25:32,840
I'm talking about a lever.
383
00:25:38,240 --> 00:25:41,920
You see, the relatively small distance
travelled by my hand
384
00:25:41,920 --> 00:25:47,400
and arm here is magnified out there at
the tip of the oar,
385
00:25:47,400 --> 00:25:50,000
which is moving far further.
386
00:25:56,880 --> 00:25:59,600
When it comes to generating movement,
387
00:25:59,600 --> 00:26:01,920
muscles are fantastic,
388
00:26:01,920 --> 00:26:03,960
but they do have their limitations.
389
00:26:06,480 --> 00:26:11,360
The lever is life's great multiplier.
390
00:26:16,520 --> 00:26:19,480
Look, a small amount of force
391
00:26:19,480 --> 00:26:22,360
applied by my arms in the boat
392
00:26:22,360 --> 00:26:24,800
is transferred to the tip of those
oars,
393
00:26:24,800 --> 00:26:29,280
and it allows me to propel the boat
forward.
394
00:26:29,280 --> 00:26:33,080
Not exactly with Olympic prowess, I
have to confess,
395
00:26:33,080 --> 00:26:35,200
but with a degree of efficiency.
396
00:26:41,280 --> 00:26:44,200
And it's thought this same principle
397
00:26:44,200 --> 00:26:46,280
helped this hulking fish
398
00:26:46,280 --> 00:26:49,080
to move with incredible delicacy...
399
00:26:50,800 --> 00:26:52,480
..by doing something
400
00:26:52,480 --> 00:26:54,480
very unfish-like.
401
00:26:59,680 --> 00:27:02,360
Using four of its lobed fins,
402
00:27:02,360 --> 00:27:05,440
along with the physics of levers,
403
00:27:05,440 --> 00:27:08,280
Onychodus turns minimum effort
404
00:27:08,280 --> 00:27:10,920
into maximum movement
405
00:27:10,920 --> 00:27:13,160
and propels itself
406
00:27:13,160 --> 00:27:16,240
stealthily across the seafloor.
407
00:27:30,240 --> 00:27:33,080
Swapping swimming for walking,
408
00:27:33,080 --> 00:27:38,520
it saves its energy for one final,
409
00:27:38,520 --> 00:27:41,000
powerful thrust.
410
00:27:47,600 --> 00:27:51,760
Thanks to its four lobed fins,
411
00:27:51,760 --> 00:27:54,960
Onychodus is a master of the ambush.
412
00:28:01,120 --> 00:28:03,200
So, with skills like these,
413
00:28:03,200 --> 00:28:07,920
you'd expect there to be plenty of
lobe-finned fish in the sea,
414
00:28:07,920 --> 00:28:13,240
but today, they have almost entirely
vanished from our waters.
415
00:28:19,800 --> 00:28:21,360
My goodness!
416
00:28:22,960 --> 00:28:25,360
That was a bit of a workout.
417
00:28:25,360 --> 00:28:29,040
Now, look, levers are very useful in
water,
418
00:28:29,040 --> 00:28:33,040
but they could become even more useful
somewhere else.
419
00:28:36,600 --> 00:28:39,000
When fish like Onychodus begin
420
00:28:39,000 --> 00:28:41,360
to use their lobed fins to walk,
421
00:28:41,360 --> 00:28:43,720
rather than swim,
422
00:28:43,720 --> 00:28:46,800
they set off a chain reaction.
423
00:28:53,120 --> 00:28:55,640
Over millions of years...
424
00:28:57,120 --> 00:28:58,840
..the thick bridge of bones
425
00:28:58,840 --> 00:29:01,600
inside those four fins lengthen...
426
00:29:04,640 --> 00:29:06,640
..and the muscles surrounding them
427
00:29:06,640 --> 00:29:08,400
shift and alter...
428
00:29:10,400 --> 00:29:14,200
..creating strong, tough appendages.
429
00:29:15,800 --> 00:29:18,360
No longer fins at all...
430
00:29:20,520 --> 00:29:24,080
..but four levered limbs.
431
00:29:25,440 --> 00:29:29,400
This was the birth of the tetrapods.
432
00:29:31,240 --> 00:29:33,960
And today, there are more than
433
00:29:33,960 --> 00:29:36,600
30,000 species,
434
00:29:36,600 --> 00:29:38,080
inhabiting every continent.
435
00:29:45,960 --> 00:29:48,200
A diverse supergroup,
436
00:29:48,200 --> 00:29:50,800
all descendants of those fish
437
00:29:50,800 --> 00:29:52,400
with four lobed fins,
438
00:29:52,400 --> 00:29:55,520
are now putting them to use
439
00:29:55,520 --> 00:29:57,480
in very different ways.
440
00:29:59,040 --> 00:30:01,480
Including the horse.
441
00:30:07,720 --> 00:30:09,960
For many tetrapods today,
442
00:30:09,960 --> 00:30:13,400
moving on land is second nature,
443
00:30:13,400 --> 00:30:17,480
but for their ancestors crawling out
of the sea,
444
00:30:17,480 --> 00:30:19,640
it was a very different story.
445
00:30:22,760 --> 00:30:25,320
Moving from one ecosystem
446
00:30:25,320 --> 00:30:28,000
to another which is completely
different,
447
00:30:28,000 --> 00:30:33,280
requires a painfully slow process of
adaptation.
448
00:30:33,280 --> 00:30:35,920
But the creatures that were making
that transition
449
00:30:35,920 --> 00:30:39,040
looked a little bit like this.
450
00:30:43,160 --> 00:30:45,080
Oh, yes.
451
00:30:46,960 --> 00:30:49,240
Look at that.
452
00:30:49,240 --> 00:30:51,040
That's special.
453
00:30:51,040 --> 00:30:53,720
One of nature's jewels.
454
00:30:53,720 --> 00:30:55,440
Absolutely beautiful.
455
00:30:55,440 --> 00:30:59,120
This is a marbled newt.
456
00:30:59,120 --> 00:31:02,720
You see how it got its name, with that
marbling running down
457
00:31:02,720 --> 00:31:04,280
its back there.
458
00:31:05,960 --> 00:31:07,880
It's an amphibian.
459
00:31:07,880 --> 00:31:11,240
It spends its spring in ponds going
through its breeding cycle
460
00:31:11,240 --> 00:31:13,960
and then at the end of summer, it
emerges onto land,
461
00:31:13,960 --> 00:31:16,080
where it spends the rest of the year.
462
00:31:16,080 --> 00:31:20,560
But, of course, it's gone through
millions of years of evolution,
463
00:31:20,560 --> 00:31:23,920
which allow it to exploit the best of
both worlds -
464
00:31:23,920 --> 00:31:26,200
the wet and the dry.
465
00:31:26,200 --> 00:31:28,320
But what about its movement?
466
00:31:28,320 --> 00:31:32,120
Well, in the ponds, it's a fairly good
swimmer, to be fair.
467
00:31:32,120 --> 00:31:33,920
What about on land?
468
00:31:33,920 --> 00:31:35,360
Let's give it a go.
469
00:31:44,560 --> 00:31:47,360
They're tentative, they're slow,
470
00:31:47,360 --> 00:31:49,480
they're laborious, they're calculated.
471
00:31:49,480 --> 00:31:52,200
Their little bodies bending from side
to side,
472
00:31:52,200 --> 00:31:54,600
as they rather lethargically
473
00:31:54,600 --> 00:31:56,320
move through the environment.
474
00:31:57,840 --> 00:32:00,760
I've never seen a newt galloping or
frolicking.
475
00:32:00,760 --> 00:32:03,160
I'm never going to. But this does
476
00:32:03,160 --> 00:32:05,640
tell us something very important.
477
00:32:07,800 --> 00:32:10,720
Movement on land is hard.
478
00:32:10,720 --> 00:32:12,160
Very hard.
479
00:32:18,960 --> 00:32:22,240
This newt can get away with having
480
00:32:22,240 --> 00:32:26,160
four left feet because in a pinch,
481
00:32:26,160 --> 00:32:28,560
it can retreat to a habitat
482
00:32:28,560 --> 00:32:31,040
it finds easier to negotiate.
483
00:32:37,840 --> 00:32:41,520
But 350 million years ago,
484
00:32:41,520 --> 00:32:43,440
if the ancestors of the horse
485
00:32:43,440 --> 00:32:45,040
were to pursue a life
486
00:32:45,040 --> 00:32:47,240
solely on solid ground,
487
00:32:47,240 --> 00:32:51,480
they would need to be far more
coordinated.
488
00:32:51,480 --> 00:32:56,400
And the answer to their coordination
conundrum came, once again,
489
00:32:56,400 --> 00:32:59,000
with an evolutionary innovation
490
00:32:59,000 --> 00:33:02,440
from the ever-adaptable muscle.
491
00:33:02,440 --> 00:33:06,600
Inside almost every muscle in my body,
492
00:33:06,600 --> 00:33:09,800
I have something called a stretch
sensor.
493
00:33:09,800 --> 00:33:13,480
And stretch sensors are highly
specialised muscle fibres
494
00:33:13,480 --> 00:33:17,520
that are constantly monitoring how and
when
495
00:33:17,520 --> 00:33:20,000
those muscles are moving.
496
00:33:20,000 --> 00:33:25,040
The key thing is that they are all
linked together in a complex web,
497
00:33:25,040 --> 00:33:27,360
so each individual muscle knows
498
00:33:27,360 --> 00:33:30,920
exactly when every...other muscle
499
00:33:30,920 --> 00:33:35,080
is moving. Now, despite the fact that
this is an incredibly
500
00:33:35,080 --> 00:33:39,240
complicated system, I bet that you've
never even thought about it,
501
00:33:39,240 --> 00:33:41,920
and that's because you don't have to,
502
00:33:41,920 --> 00:33:43,880
despite the fact that it's crucial
503
00:33:43,880 --> 00:33:46,200
for every single move that we make.
504
00:33:55,800 --> 00:33:59,960
Tiny stretch sensors allow the muscles
to communicate
505
00:33:59,960 --> 00:34:02,360
with the central nervous system,
506
00:34:02,360 --> 00:34:05,240
giving us and most living tetrapods
507
00:34:05,240 --> 00:34:07,560
the ability to co-ordinate movement
508
00:34:07,560 --> 00:34:10,120
with astonishing precision.
509
00:34:10,120 --> 00:34:13,360
Often, faster than you can think.
510
00:34:20,360 --> 00:34:22,000
Look at that.
511
00:34:28,200 --> 00:34:30,160
Just look at the legs there.
512
00:34:30,160 --> 00:34:33,960
Every part of them is moving
independently,
513
00:34:33,960 --> 00:34:36,000
in isolation, at the same time.
514
00:34:36,000 --> 00:34:38,600
And then the weight -
515
00:34:38,600 --> 00:34:42,640
that's got to be balanced between all
four feet.
516
00:34:42,640 --> 00:34:44,760
And running down those legs -
517
00:34:44,760 --> 00:34:47,520
just going to speed it up, look at
that -
518
00:34:47,520 --> 00:34:50,560
are ripples of muscles.
519
00:34:50,560 --> 00:34:52,880
That's the glutes, that's the quads,
520
00:34:52,880 --> 00:34:57,040
that's the hamstrings, all working in
unison.
521
00:35:00,040 --> 00:35:02,200
Without these little gizmos,
522
00:35:02,200 --> 00:35:04,560
these stretch sensors hiding in
muscles
523
00:35:04,560 --> 00:35:07,400
and the complex network that joins
them all together,
524
00:35:07,400 --> 00:35:11,840
animals with bodies like this simply
would not have been able to evolve.
525
00:35:15,880 --> 00:35:18,320
It was down to this innovation
526
00:35:18,320 --> 00:35:19,960
that animal bodies could become
527
00:35:19,960 --> 00:35:22,360
radically more coordinated,
528
00:35:22,360 --> 00:35:25,800
and those tiny little bones, once
hidden in those fish's fins,
529
00:35:25,800 --> 00:35:27,680
could really come into their own.
530
00:35:29,680 --> 00:35:33,280
Those fully terrestrial animals
531
00:35:33,280 --> 00:35:38,320
could put one foot in front of the
other with extreme precision...
532
00:35:40,320 --> 00:35:42,680
..and this was a game-changer.
533
00:35:48,040 --> 00:35:50,440
Time for us to motor on.
534
00:35:53,560 --> 00:35:56,760
Over the next 300 million years,
535
00:35:56,760 --> 00:35:59,320
the tetrapods scattered across the
Earth.
536
00:36:05,240 --> 00:36:08,400
Whilst life faced some cosmic
curveballs...
537
00:36:10,200 --> 00:36:12,320
..it was never fully derailed.
538
00:36:14,640 --> 00:36:16,440
And evolution carried on...
539
00:36:19,600 --> 00:36:21,280
..tumbling us...
540
00:36:25,080 --> 00:36:26,720
..into a new world...
541
00:36:30,920 --> 00:36:32,560
..where the way you move...
542
00:36:34,080 --> 00:36:37,720
..can be a matter of life
543
00:36:37,720 --> 00:36:39,360
and death.
544
00:36:44,400 --> 00:36:46,640
This is Phenacodus.
545
00:36:54,280 --> 00:36:57,560
Life looks pretty serene,
546
00:36:57,560 --> 00:37:00,600
but Phenacodus must constantly
547
00:37:00,600 --> 00:37:04,200
be on guard, because this world
548
00:37:04,200 --> 00:37:06,880
is full of expert movers...
549
00:37:06,880 --> 00:37:08,400
BRANCH SNAPS
550
00:37:08,400 --> 00:37:10,120
..whose bodies...
551
00:37:12,080 --> 00:37:14,640
..have evolved for the chase.
552
00:37:18,280 --> 00:37:20,640
GROWLING
When the hunt is on...
553
00:37:20,640 --> 00:37:23,920
..surging adrenaline, thumping hearts
554
00:37:23,920 --> 00:37:26,800
and straining muscles will only take
you so far.
555
00:37:31,280 --> 00:37:33,360
Faced with a situation it can't
556
00:37:33,360 --> 00:37:35,040
muscle its way out of...
557
00:37:36,920 --> 00:37:39,080
..the secret to Phenacodus's
558
00:37:39,080 --> 00:37:43,320
survival lies in its feet.
559
00:37:48,000 --> 00:37:50,200
Come on, Siddy! Nance, come on!
560
00:37:50,200 --> 00:37:51,760
DOG BARKS
561
00:37:56,880 --> 00:38:00,960
Do you know, sometimes, people say,
"Why poodles?
562
00:38:00,960 --> 00:38:03,680
"Why poodles?" they say. And I
facetiously reply,
563
00:38:03,680 --> 00:38:05,200
"Are there other breeds of dog?"
564
00:38:05,200 --> 00:38:06,400
I mean, look at them.
565
00:38:06,400 --> 00:38:09,800
Boundless energy, incredibly loyal,
566
00:38:09,800 --> 00:38:11,400
and they can also help us
567
00:38:11,400 --> 00:38:14,200
with an important part of our story.
568
00:38:14,200 --> 00:38:16,000
You see, hidden beneath
569
00:38:16,000 --> 00:38:18,960
this curly fur here is a crucial
570
00:38:18,960 --> 00:38:21,880
step change in evolution.
571
00:38:21,880 --> 00:38:24,720
Now, I don't need to tell you about my
foot and leg,
572
00:38:24,720 --> 00:38:27,000
you've got your own. Starts off at the
toe,
573
00:38:27,000 --> 00:38:28,560
goes across the foot to the ankle,
574
00:38:28,560 --> 00:38:32,400
then you've got the shin, the knee,
the thigh.
575
00:38:32,400 --> 00:38:34,400
We put our feet down
576
00:38:34,400 --> 00:38:36,040
onto the ground, we plant them
577
00:38:36,040 --> 00:38:38,200
flat on the ground like that.
578
00:38:38,200 --> 00:38:39,560
We're what we call
579
00:38:39,560 --> 00:38:43,520
plantigrade animals. It's quite an
efficient way of walking.
580
00:38:43,520 --> 00:38:46,720
Nancy, on the other hand, is
altogether different.
581
00:38:46,720 --> 00:38:48,920
Let's take a look at her back leg
here.
582
00:38:48,920 --> 00:38:51,280
You see, her toes stretch
583
00:38:51,280 --> 00:38:52,760
from here to here.
584
00:38:52,760 --> 00:38:54,640
The rest of her foot bones
585
00:38:54,640 --> 00:38:56,280
all the way up to here, which looks
586
00:38:56,280 --> 00:38:57,840
like a backward-pointing knee,
587
00:38:57,840 --> 00:39:01,120
but this is, in fact, her ankle.
588
00:39:01,120 --> 00:39:02,840
Her knee is all the way
589
00:39:02,840 --> 00:39:04,520
up here. So Nancy
590
00:39:04,520 --> 00:39:07,120
is effectively standing up
591
00:39:07,120 --> 00:39:10,040
on her toe bones.
592
00:39:10,040 --> 00:39:13,280
She's a digitigrade animal,
593
00:39:13,280 --> 00:39:15,320
and that's altogether different.
594
00:39:15,320 --> 00:39:18,240
It means that you move in a very
different way, doesn't it?
595
00:39:18,240 --> 00:39:19,920
Shall we show them?
596
00:39:19,920 --> 00:39:22,400
Come on, let's go. Come on.
597
00:39:30,880 --> 00:39:33,760
Right, Sid, Nancy.
598
00:39:33,760 --> 00:39:35,520
Let's see them in action.
599
00:39:35,520 --> 00:39:37,040
BARKING
600
00:39:42,000 --> 00:39:44,840
Woo-hoo-hoo!
BARKING
601
00:39:44,840 --> 00:39:46,560
Look at them go! You see,
602
00:39:46,560 --> 00:39:50,360
this change in anatomy allows the leg
to become longer,
603
00:39:50,360 --> 00:39:52,400
the stride to become longer,
604
00:39:52,400 --> 00:39:56,080
and more efficient use of all of that
elastic energy
605
00:39:56,080 --> 00:39:58,800
stored in the muscles and tendons
606
00:39:58,800 --> 00:40:00,720
above their ankle.
607
00:40:00,720 --> 00:40:01,880
Look at that!
608
00:40:01,880 --> 00:40:03,200
Bouncing about.
609
00:40:03,200 --> 00:40:05,160
BARKING
610
00:40:05,160 --> 00:40:08,320
Alacrity, agility.
611
00:40:08,320 --> 00:40:10,320
Critically, speed.
612
00:40:10,320 --> 00:40:13,240
That is a happy poodle.
613
00:40:14,480 --> 00:40:17,680
And, you know, this adaptation has
occurred a number of times
614
00:40:17,680 --> 00:40:21,280
in terrestrial animals. But having
said that,
615
00:40:21,280 --> 00:40:25,120
if you really want to be a creature
living life in the fast lane,
616
00:40:25,120 --> 00:40:29,640
evolution can offer you one more gear.
617
00:40:29,640 --> 00:40:32,080
Siddy, Nance, come on! Come on!
618
00:40:34,280 --> 00:40:38,360
When it comes to speed and efficiency,
plantigrade -
619
00:40:38,360 --> 00:40:41,760
that's us - will get you from A to B.
620
00:40:41,760 --> 00:40:44,920
Digitigrade - like my dogs -
621
00:40:44,920 --> 00:40:47,040
ups the revs.
622
00:40:48,760 --> 00:40:51,520
But 56 million years ago,
623
00:40:51,520 --> 00:40:55,440
Phenacodus was on the verge of
something new.
624
00:40:56,480 --> 00:41:00,800
Not just bouncing on the balls of its
feet,
625
00:41:00,800 --> 00:41:05,440
but pushing off from the very tips of
its toes...
626
00:41:08,920 --> 00:41:11,680
..lengthening its stride even further.
627
00:41:13,040 --> 00:41:16,200
So future generations take the
concept...
628
00:41:17,320 --> 00:41:18,920
..and run with it.
629
00:41:23,920 --> 00:41:25,960
As bones elongate
630
00:41:25,960 --> 00:41:27,560
and muscles bulk up...
631
00:41:28,800 --> 00:41:30,320
..they spend more
632
00:41:30,320 --> 00:41:32,600
and more time on tiptoe...
633
00:41:35,920 --> 00:41:37,320
..and in the process...
634
00:41:38,840 --> 00:41:40,600
..find the most efficiency
635
00:41:40,600 --> 00:41:42,480
in trading many toes
636
00:41:42,480 --> 00:41:45,600
for one large,
637
00:41:45,600 --> 00:41:47,600
powerful shock absorber.
638
00:41:52,720 --> 00:41:54,520
Look at this.
639
00:41:54,520 --> 00:41:57,520
This is clearly a cast
640
00:41:57,520 --> 00:41:59,880
of a fossil of a hoof.
641
00:41:59,880 --> 00:42:04,120
A hoof at the end of a very long leg.
642
00:42:04,120 --> 00:42:08,080
A leg that's clearly all about
movement.
643
00:42:08,080 --> 00:42:11,800
A leg, though, that is surprisingly
different than ours.
644
00:42:11,800 --> 00:42:13,840
You see, essentially, it's foot
645
00:42:13,840 --> 00:42:15,680
all the way from here to here.
646
00:42:15,680 --> 00:42:18,480
This is the equivalent of our ankle.
647
00:42:18,480 --> 00:42:21,120
The bone here would be like those in
the sole of our foot.
648
00:42:21,120 --> 00:42:22,480
And down here,
649
00:42:22,480 --> 00:42:26,480
it's balancing on a single tiptoe.
650
00:42:26,480 --> 00:42:29,520
The hoof itself would have been made
of keratin,
651
00:42:29,520 --> 00:42:31,560
just like our fingernail.
652
00:42:31,560 --> 00:42:33,640
And also, what's interesting is at the
other end,
653
00:42:33,640 --> 00:42:36,640
the front legs weren't attached to the
skeleton.
654
00:42:36,640 --> 00:42:38,080
They were embedded
655
00:42:38,080 --> 00:42:40,880
in a heavy mass of powerful muscle,
656
00:42:40,880 --> 00:42:45,360
and this gave it the capacity for a
greater stride.
657
00:42:45,360 --> 00:42:47,480
You see this groove here?
658
00:42:47,480 --> 00:42:50,040
Running down here would have been a
tendon,
659
00:42:50,040 --> 00:42:51,920
perhaps half a metre long,
660
00:42:51,920 --> 00:42:54,920
a giant elastic band.
661
00:42:54,920 --> 00:42:57,360
But it is a leg with compromises.
662
00:42:57,360 --> 00:43:00,480
I mean, you can't pick anything up
with a hoof,
663
00:43:00,480 --> 00:43:02,040
you can't manipulate anything.
664
00:43:02,040 --> 00:43:04,440
It's lost all dexterity,
665
00:43:04,440 --> 00:43:06,720
at the expense of speed.
666
00:43:09,000 --> 00:43:13,160
This three-million-year-old hoof
667
00:43:13,160 --> 00:43:15,720
tells us of the arrival
668
00:43:15,720 --> 00:43:19,080
of a new group of animals.
669
00:43:19,080 --> 00:43:22,360
Animals we call Equus.
670
00:43:34,560 --> 00:43:37,040
These single-hoofed mammals
671
00:43:37,040 --> 00:43:40,040
first evolved on the plains of North
America...
672
00:43:42,160 --> 00:43:44,440
..before spreading across the globe.
673
00:43:47,160 --> 00:43:49,600
Among them
674
00:43:49,600 --> 00:43:52,560
was one remarkable species.
675
00:43:54,720 --> 00:43:57,200
Equus ferus.
676
00:44:00,360 --> 00:44:04,560
Known to you and I as the horse.
677
00:44:10,720 --> 00:44:12,400
Its body shaped
678
00:44:12,400 --> 00:44:14,680
generation after generation...
679
00:44:19,520 --> 00:44:22,200
..by the evolutionary drive to move.
680
00:44:25,560 --> 00:44:29,080
700 muscles, passed down
681
00:44:29,080 --> 00:44:31,240
over half a billion years,
682
00:44:31,240 --> 00:44:34,040
from a pioneer who changed the world.
683
00:44:34,040 --> 00:44:37,440
A huge heart, with an ancient beat,
684
00:44:37,440 --> 00:44:41,000
that began deep beneath the waves.
685
00:44:41,000 --> 00:44:43,240
Long levered limbs
686
00:44:43,240 --> 00:44:46,800
that once helped a fish to walk...
687
00:44:48,360 --> 00:44:51,120
..and four large hooves,
688
00:44:51,120 --> 00:44:53,160
the legacy of ancestors
689
00:44:53,160 --> 00:44:56,280
who had to run for their lives.
690
00:44:57,600 --> 00:45:01,000
But there's one final twist
691
00:45:01,000 --> 00:45:03,360
in the story of the horse,
692
00:45:03,360 --> 00:45:05,240
because Equus ferus
693
00:45:05,240 --> 00:45:07,560
was about to encounter
694
00:45:07,560 --> 00:45:09,960
a new force of evolution.
695
00:45:17,400 --> 00:45:19,200
Another species
696
00:45:19,200 --> 00:45:22,760
on an evolutionary journey of its own.
697
00:45:22,760 --> 00:45:25,000
A bipedal tetrapod,
698
00:45:25,000 --> 00:45:27,240
with opposable thumbs,
699
00:45:27,240 --> 00:45:31,360
and an overinflated sense of
self-worth.
700
00:45:48,720 --> 00:45:51,960
4,000 years ago, Homo sapiens -
701
00:45:51,960 --> 00:45:53,840
that's us - inhabited
702
00:45:53,840 --> 00:45:55,320
much of the planet.
703
00:45:55,320 --> 00:45:56,840
HORSE WHINNIES
704
00:45:56,840 --> 00:45:59,880
We had city states and agriculture.
705
00:45:59,880 --> 00:46:02,640
Empires were beginning to grow.
706
00:46:04,840 --> 00:46:07,720
And at this time, in Europe and Asia,
707
00:46:07,720 --> 00:46:09,520
we begin to see evidence
708
00:46:09,520 --> 00:46:12,040
of a growing relationship
709
00:46:12,040 --> 00:46:14,160
between horses
710
00:46:14,160 --> 00:46:15,960
and humans.
711
00:46:18,640 --> 00:46:23,160
Now, no-one is exactly sure how the
first horse was tamed.
712
00:46:23,160 --> 00:46:25,560
Maybe someone caught one of those wild
horses,
713
00:46:25,560 --> 00:46:28,520
took it into captivity, gave it
shelter, food,
714
00:46:28,520 --> 00:46:32,240
cared for it, loved it and trained it.
715
00:46:32,240 --> 00:46:35,400
But what we do know is that in pretty
short time,
716
00:46:35,400 --> 00:46:40,080
we took these strong, efficient,
powerful animals
717
00:46:40,080 --> 00:46:43,920
and turned them into our perfect
companions.
718
00:46:43,920 --> 00:46:46,520
And, you know, we didn't just tame
them.
719
00:46:46,520 --> 00:46:49,840
Over generation after generation, we
bred them,
720
00:46:49,840 --> 00:46:52,560
choosing those characteristics which
favoured the way
721
00:46:52,560 --> 00:46:55,600
we wanted horses to be.
722
00:46:55,600 --> 00:46:58,520
So in the end, we took the wild horse
723
00:46:58,520 --> 00:47:01,800
and we turned it into the workhorse.
724
00:47:14,640 --> 00:47:16,760
We chose the strongest.
725
00:47:18,320 --> 00:47:20,000
We chose the most powerful.
726
00:47:21,560 --> 00:47:24,640
But we also chose the friendliest,
727
00:47:24,640 --> 00:47:26,880
the most amenable.
728
00:47:29,840 --> 00:47:32,480
And for better or for worse,
729
00:47:32,480 --> 00:47:34,560
over the generations,
730
00:47:34,560 --> 00:47:36,960
the horse was altered.
731
00:47:40,560 --> 00:47:42,520
The ancestors of the modern horse
732
00:47:42,520 --> 00:47:44,160
were a pretty wild bunch.
733
00:47:45,280 --> 00:47:47,800
Diverse not only in terms of their
physical appearance,
734
00:47:47,800 --> 00:47:50,760
but also, their genetic make-up.
735
00:47:50,760 --> 00:47:52,880
And about 4,000 years ago,
736
00:47:52,880 --> 00:47:55,800
we see two gene variants appear.
737
00:47:55,800 --> 00:47:57,160
HORSE WHINNIES
738
00:47:57,160 --> 00:47:59,960
Now, one of those appears to make them
less aggressive,
739
00:47:59,960 --> 00:48:01,520
more manageable.
740
00:48:03,680 --> 00:48:07,080
And the other, which appears to give
them a stronger back,
741
00:48:07,080 --> 00:48:09,760
making them easier to ride.
742
00:48:09,760 --> 00:48:11,520
Now, what's interesting is that
743
00:48:11,520 --> 00:48:14,000
within the space of just a few hundred
years,
744
00:48:14,000 --> 00:48:16,040
we'd spread those gene variants
745
00:48:16,040 --> 00:48:18,400
throughout the population.
746
00:48:20,200 --> 00:48:22,960
The wild horse was effectively gone.
747
00:48:22,960 --> 00:48:25,840
We had one global species,
748
00:48:25,840 --> 00:48:28,600
selected by humans.
749
00:48:28,600 --> 00:48:30,080
You.
750
00:48:30,080 --> 00:48:33,320
Yes. I know.
751
00:48:33,320 --> 00:48:35,320
It wasn't my fault.
752
00:48:35,320 --> 00:48:37,040
I wasn't around then.
753
00:48:49,160 --> 00:48:52,480
Today, the horse goes by a new name.
754
00:48:54,160 --> 00:48:58,160
Equus ferus caballus.
755
00:48:58,160 --> 00:49:00,080
The domestic horse.
756
00:49:01,560 --> 00:49:04,120
Our relationship is a special one.
757
00:49:05,960 --> 00:49:07,560
Together, we've travelled to
758
00:49:07,560 --> 00:49:09,480
every corner of the globe.
759
00:49:11,400 --> 00:49:12,960
Step by step...
760
00:49:14,320 --> 00:49:15,960
..and side by side.
761
00:49:21,520 --> 00:49:23,400
We often think of evolution
762
00:49:23,400 --> 00:49:25,360
as a battle between species,
763
00:49:25,360 --> 00:49:27,520
a game of winners and losers,
764
00:49:27,520 --> 00:49:29,880
a game of survival of the fittest.
765
00:49:29,880 --> 00:49:33,000
But very occasionally, species come
together
766
00:49:33,000 --> 00:49:36,880
and the result is greater than the sum
of their parts.
767
00:49:36,880 --> 00:49:40,440
Now, there's no doubt we played a
hugely instrumental role
768
00:49:40,440 --> 00:49:42,200
in the evolution of the horse,
769
00:49:42,200 --> 00:49:45,800
but then the horse has had an impact
on us too,
770
00:49:45,800 --> 00:49:50,880
because without this remarkable animal
as our greatest partner,
771
00:49:50,880 --> 00:49:55,040
we simply wouldn't be the species we
are today.
772
00:49:59,000 --> 00:50:01,800
The horse's evolutionary journey
773
00:50:01,800 --> 00:50:03,680
is just one thread
774
00:50:03,680 --> 00:50:06,360
in an extraordinary tapestry...
775
00:50:07,880 --> 00:50:11,800
..that weaves together every animal,
776
00:50:11,800 --> 00:50:14,520
in fact, every living thing
777
00:50:14,520 --> 00:50:16,240
on our planet.
778
00:50:17,920 --> 00:50:21,080
It's taken four billion years
779
00:50:21,080 --> 00:50:23,560
to get here, but, boy,
780
00:50:23,560 --> 00:50:27,000
has life come a very, very long way!
781
00:50:30,080 --> 00:50:33,000
From the cell that began it all...
782
00:50:35,160 --> 00:50:36,640
..to sex...
783
00:50:37,760 --> 00:50:39,560
..to competition...
784
00:50:40,840 --> 00:50:43,120
..to predation and protection.
785
00:50:49,560 --> 00:50:52,920
From the oceans to the land
786
00:50:52,920 --> 00:50:56,320
and, for some, back again.
787
00:50:59,680 --> 00:51:03,320
For others, onwards to the skies.
788
00:51:05,520 --> 00:51:08,560
There was a bum that changed the
world.
789
00:51:09,800 --> 00:51:11,880
There were jaws, limbs,
790
00:51:11,880 --> 00:51:14,600
hearts and minds.
791
00:51:14,600 --> 00:51:17,720
Minds which have evolved to sense,
792
00:51:17,720 --> 00:51:20,400
to move, to love,
793
00:51:20,400 --> 00:51:22,080
to contemplate...
794
00:51:25,160 --> 00:51:27,560
..and, in our case,
795
00:51:27,560 --> 00:51:29,000
to begin to understand
796
00:51:29,000 --> 00:51:31,320
our own origins.
797
00:51:37,040 --> 00:51:39,840
A journey of knowledge
798
00:51:39,840 --> 00:51:41,880
that we're still on today.
799
00:51:44,520 --> 00:51:47,000
There's an outdated view,
800
00:51:47,000 --> 00:51:48,960
a mistaken idea,
801
00:51:48,960 --> 00:51:53,960
that we humans are the be-all and
end-all of evolution.
802
00:51:53,960 --> 00:51:56,480
That everything we've explored,
everything we've shown you
803
00:51:56,480 --> 00:52:02,280
in this series was just about making
us the perfect organism,
804
00:52:02,280 --> 00:52:05,000
the paragon of life on Earth.
805
00:52:05,000 --> 00:52:07,760
But it's simply not true.
806
00:52:07,760 --> 00:52:10,680
We're not perfect and we weren't made.
807
00:52:10,680 --> 00:52:13,760
We've been shaped by exactly the same
forces
808
00:52:13,760 --> 00:52:19,440
that have shaped every organism that's
ever lived on this planet.
809
00:52:19,440 --> 00:52:22,040
And through a startling twist of fate,
810
00:52:22,040 --> 00:52:24,480
we are now having a profound effect
811
00:52:24,480 --> 00:52:26,920
on evolution ourselves.
812
00:52:26,920 --> 00:52:30,160
A dramatic, rapid and scary one
813
00:52:30,160 --> 00:52:33,120
because of what we're doing to our
environment
814
00:52:33,120 --> 00:52:38,800
and because we're driving a massive
extinction event.
815
00:52:38,800 --> 00:52:43,760
Now, evolution does feast on
extinction.
816
00:52:43,760 --> 00:52:47,320
It loves the opportunities, the
vacancies.
817
00:52:47,320 --> 00:52:51,160
So whatever we do now, life will go
on.
818
00:52:51,160 --> 00:52:54,280
Life will be bright, life will be
beautiful,
819
00:52:54,280 --> 00:52:57,720
life will be wonderful.
820
00:52:57,720 --> 00:53:01,880
But in evolutionary terms, what about
us?
821
00:53:01,880 --> 00:53:04,360
Could we become shorter,
822
00:53:04,360 --> 00:53:06,640
slower, more short-sighted?
823
00:53:06,640 --> 00:53:10,720
Might we become smarter, more stupid?
824
00:53:12,160 --> 00:53:16,360
I don't think it really matters about
our anatomy at this point.
825
00:53:17,680 --> 00:53:20,760
I think what matters is how we think,
826
00:53:20,760 --> 00:53:25,520
imagine and create our way out of our
situation.
827
00:53:27,000 --> 00:53:31,880
I think that what needs to be driving
human evolution right now...
828
00:53:33,400 --> 00:53:34,720
..is hope.
829
00:53:57,200 --> 00:53:58,920
But before we go...
830
00:54:01,560 --> 00:54:03,280
..how did we bring the story
831
00:54:03,280 --> 00:54:05,240
of evolution to life?
832
00:54:08,600 --> 00:54:10,400
The way that one animal,
833
00:54:10,400 --> 00:54:11,720
over millions of years,
834
00:54:11,720 --> 00:54:14,680
can transform into something radically
different
835
00:54:14,680 --> 00:54:17,520
was once a mystery lost to time.
836
00:54:19,240 --> 00:54:21,680
- If we think about a book, we have
lots of different pages
837
00:54:21,680 --> 00:54:23,600
that tell us the story from start to
finish.
838
00:54:25,040 --> 00:54:28,080
However, with evolution and fossils,
some of those pages are missing.
839
00:54:30,080 --> 00:54:32,080
- But occasionally, evidence
840
00:54:32,080 --> 00:54:34,040
is unearthed of the process
841
00:54:34,040 --> 00:54:38,640
in action. In 2004, palaeontologists
842
00:54:38,640 --> 00:54:40,400
in the Canadian Arctic
843
00:54:40,400 --> 00:54:43,240
discovered a ground-breaking fossil.
844
00:54:43,240 --> 00:54:45,440
- So this is a cast of Tiktaalik.
845
00:54:45,440 --> 00:54:49,640
Now, Tiktaalik lived about 375 million
years ago,
846
00:54:49,640 --> 00:54:51,720
and it's got the scales very much
847
00:54:51,720 --> 00:54:53,960
like modern-day fish have today.
848
00:54:53,960 --> 00:54:56,920
And what's quite unusual is that it
actually has a neck.
849
00:54:56,920 --> 00:54:58,480
And these bones that are around there,
850
00:54:58,480 --> 00:54:59,800
these are the sort of collar bone
851
00:54:59,800 --> 00:55:01,480
or shoulder girdle. It looks like
852
00:55:01,480 --> 00:55:04,000
a cross between a fish and an
amphibian,
853
00:55:04,000 --> 00:55:07,000
and that's because that's exactly what
it is.
854
00:55:07,000 --> 00:55:08,400
- Tiktaalik was really this kind of
855
00:55:08,400 --> 00:55:10,480
unique snapshot in evolutionary time
856
00:55:10,480 --> 00:55:12,480
at this key moment
857
00:55:12,480 --> 00:55:14,240
for the water-to-land transition.
858
00:55:15,680 --> 00:55:17,160
- So it's a perfect example of
859
00:55:17,160 --> 00:55:18,400
a transitional fossil.
860
00:55:18,400 --> 00:55:20,440
- Transitional fossils are incredibly
rare.
861
00:55:21,640 --> 00:55:24,080
They play the really important role of
filling those gaps
862
00:55:24,080 --> 00:55:26,880
between morphologies that we kind of
know are there,
863
00:55:26,880 --> 00:55:28,720
but we don't really know exactly
864
00:55:28,720 --> 00:55:30,840
what they might have looked like.
865
00:55:30,840 --> 00:55:33,400
- Transitional fossils represent
866
00:55:33,400 --> 00:55:35,200
just one out of millions,
867
00:55:35,200 --> 00:55:37,760
possibly billions, of individuals
868
00:55:37,760 --> 00:55:39,240
that, over generations,
869
00:55:39,240 --> 00:55:42,040
contribute to evolutionary change.
870
00:55:42,040 --> 00:55:45,040
Coming up with a way to illustrate
this
871
00:55:45,040 --> 00:55:47,040
posed a huge challenge
872
00:55:47,040 --> 00:55:49,760
to the visual effects team behind the
series.
873
00:55:49,760 --> 00:55:52,160
- Evolution does not move in a
straight line,
874
00:55:52,160 --> 00:55:54,440
because it is purely opportunistic
875
00:55:54,440 --> 00:55:55,880
and slightly haphazard.
876
00:55:55,880 --> 00:55:58,960
- It's tinkering. It's messing with
what's already there,
877
00:55:58,960 --> 00:56:00,440
rather than kind of always
878
00:56:00,440 --> 00:56:03,200
necessarily inventing something from
scratch.
879
00:56:03,200 --> 00:56:05,800
- It's all about a great grand
experiment
880
00:56:05,800 --> 00:56:07,280
and just seeing what happens.
881
00:56:08,600 --> 00:56:11,240
- The team spent thousands of hours
882
00:56:11,240 --> 00:56:12,960
crafting and animating
883
00:56:12,960 --> 00:56:14,760
computer-generated models
884
00:56:14,760 --> 00:56:16,200
to bring ancient animals
885
00:56:16,200 --> 00:56:17,520
back to life.
886
00:56:17,520 --> 00:56:19,800
But to illustrate the randomness
887
00:56:19,800 --> 00:56:23,160
and variation seen as life evolves,
888
00:56:23,160 --> 00:56:25,680
they needed to experiment.
889
00:56:25,680 --> 00:56:28,720
After consulting scientists to
accurately model
890
00:56:28,720 --> 00:56:30,960
the key evolutionary changes,
891
00:56:30,960 --> 00:56:33,120
they used generative AI software
892
00:56:33,120 --> 00:56:36,480
to create hundreds of variations,
893
00:56:36,480 --> 00:56:39,280
representing countless generations.
894
00:56:39,280 --> 00:56:42,440
And by hand-selecting and merging
895
00:56:42,440 --> 00:56:44,520
the best results with their original
896
00:56:44,520 --> 00:56:46,440
animations, they were able
897
00:56:46,440 --> 00:56:48,200
to condense millions of years
898
00:56:48,200 --> 00:56:50,120
of evolution...
899
00:56:50,120 --> 00:56:51,600
- Look at that!
- There's bones inside!
900
00:56:51,600 --> 00:56:52,800
- No way!
901
00:56:52,800 --> 00:56:55,600
- ..into a matter of seconds.
902
00:56:55,600 --> 00:56:57,160
- In reality, this would take
903
00:56:57,160 --> 00:56:58,520
millions of years.
904
00:57:00,440 --> 00:57:01,920
- This is a fantastic way
905
00:57:01,920 --> 00:57:04,440
to illustrate the evolution of form.
906
00:57:04,440 --> 00:57:06,640
This is basically how I imagine it
playing out in my head.
907
00:57:17,440 --> 00:57:18,960
- This series has been over
908
00:57:18,960 --> 00:57:21,200
four billion years in the making...
909
00:57:22,680 --> 00:57:25,080
..and as a certain Charles Darwin
910
00:57:25,080 --> 00:57:26,840
once wrote,
911
00:57:26,840 --> 00:57:29,280
"From so simple a beginning
912
00:57:29,280 --> 00:57:32,120
"endless forms most beautiful
913
00:57:32,120 --> 00:57:34,480
"and most wonderful have been,
914
00:57:34,480 --> 00:57:37,320
"and are being evolved."
915
00:57:37,320 --> 00:57:40,120
- One of the big key life lessons that
916
00:57:40,120 --> 00:57:42,000
I've learned from studying evolution
917
00:57:42,000 --> 00:57:44,360
is that change is constant
918
00:57:44,360 --> 00:57:46,640
and change is the norm. So things
919
00:57:46,640 --> 00:57:48,240
have always changed and will always
920
00:57:48,240 --> 00:57:49,800
continue to change, and life
921
00:57:49,800 --> 00:57:51,160
will always continue to adapt.
922
00:57:54,160 --> 00:57:55,880
- That's how it's always been,
923
00:57:55,880 --> 00:57:57,120
and there's no reason to believe
924
00:57:57,120 --> 00:57:58,960
that's not how it's going to continue
to be.
925
00:58:11,520 --> 00:58:15,040
- Do you want to know how an elephant
is related to a clownfish?
926
00:58:15,040 --> 00:58:18,760
Discover more in a poster from the
Open University on
927
00:58:18,760 --> 00:58:20,760
the tree of life. To get your free
copy,
928
00:58:20,760 --> 00:58:23,360
scan the QR code on-screen or ring...
929
00:58:27,040 --> 00:58:28,520
..or visit...
66715
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