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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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{\an8}Over half a billion years ago,
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{\an8}this slab of rock...
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{\an8}..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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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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{\an8}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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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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{\an8}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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{\an8}It stretches forward
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{\an8}using those circular muscles,
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{\an8}and then contracts
its longitudinal muscles
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{\an8}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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{\an8}Something that I find
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{\an8}quite therapeutic.
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{\an8}You may consider it perverse,
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{\an8}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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{\an8}As they say, necessity
is the mother of invention,
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{\an8}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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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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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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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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Just like the rest of its kind,
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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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spending their energy just
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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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faster, stronger.
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Its remarkable athletic ability
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is thanks to an innovative use
of muscle
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that unlocked the full potential
of the heart.
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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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it requires a stimulus, an order,
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and that typically comes
in the form of a tiny electric zap.
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{\an8}And it's thought that some
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{\an8}muscle cells inside some of
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00:18:16,000 --> 00:18:19,000
{\an8}the earliest hearts took charge,
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{\an8}specialised and started to send out
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00:18:22,000 --> 00:18:25,000
a series of rhythmic zaps.
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And all of the surrounding muscle
cells complied by contracting,
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00:18:29,000 --> 00:18:33,000
generating a single powerful pulse.
272
00:18:35,000 --> 00:18:38,000
Now, these mutant zapping cells
273
00:18:38,000 --> 00:18:41,000
are called pacemakers,
and almost all animals have them.
274
00:18:41,000 --> 00:18:46,000
We have a single primary pacemaker
called the sinoatrial node.
275
00:18:46,000 --> 00:18:51,000
And as soon as those
ancient pacemakers began to pulse,
276
00:18:51,000 --> 00:18:54,000
they instigated a revolution.
277
00:18:58,000 --> 00:19:01,000
In the ancestor of the horse,
278
00:19:01,000 --> 00:19:04,000
those specialised pacemaker cells
279
00:19:04,000 --> 00:19:05,000
have now clustered together
280
00:19:05,000 --> 00:19:07,000
in a localised region...
281
00:19:07,000 --> 00:19:09,000
HEARTBEAT
282
00:19:11,000 --> 00:19:12,000
..giving its heart
283
00:19:12,000 --> 00:19:14,000
a more powerful beat.
284
00:19:20,000 --> 00:19:22,000
And over many generations...
285
00:19:24,000 --> 00:19:26,000
..the beat gets stronger.
286
00:19:30,000 --> 00:19:33,000
The muscle walls around
the pacemaker thicken...
287
00:19:36,000 --> 00:19:38,000
..chambers form...
288
00:19:40,000 --> 00:19:41,000
..and valves...
289
00:19:42,000 --> 00:19:44,000
..directing blood flow
290
00:19:44,000 --> 00:19:46,000
around the body...
291
00:19:51,000 --> 00:19:53,000
..becoming an iconic,
292
00:19:53,000 --> 00:19:55,000
life-sustaining organ.
293
00:19:58,000 --> 00:20:01,000
It's an ingenious use of muscle,
294
00:20:01,000 --> 00:20:05,000
one that transformed
animal locomotion.
295
00:20:07,000 --> 00:20:10,000
When hearts went from being
a simple pump to a more complex
296
00:20:10,000 --> 00:20:12,000
muscular mechanism,
297
00:20:12,000 --> 00:20:17,000
it led to a step change
in the evolution of movement.
298
00:20:17,000 --> 00:20:20,000
It allowed animals to become
bigger, stronger, faster.
299
00:20:20,000 --> 00:20:25,000
It allowed them to get off of
that seabed into the world above.
300
00:20:25,000 --> 00:20:27,000
And from that point on,
301
00:20:27,000 --> 00:20:30,000
life would become a slithering,
302
00:20:30,000 --> 00:20:32,000
crawling, walking, running,
303
00:20:32,000 --> 00:20:35,000
jumping and climbing adventure.
304
00:20:35,000 --> 00:20:37,000
Today...
305
00:20:38,000 --> 00:20:41,000
..across the globe,
306
00:20:41,000 --> 00:20:43,000
beating hearts are pumping oxygen
307
00:20:43,000 --> 00:20:45,000
through all sorts of bodies.
308
00:20:48,000 --> 00:20:51,000
Around 2.5 billion heartbeats
309
00:20:51,000 --> 00:20:53,000
will supply your muscles with
310
00:20:53,000 --> 00:20:55,000
the energy they need...
311
00:20:56,000 --> 00:20:59,000
..from your first breath
312
00:20:59,000 --> 00:21:02,000
till your last.
313
00:21:04,000 --> 00:21:08,000
It's a rhythm that connects us all
314
00:21:08,000 --> 00:21:11,000
to the first beats,
315
00:21:11,000 --> 00:21:14,000
over half a billion years ago.
316
00:21:18,000 --> 00:21:21,000
Time to take a leap forward...
317
00:21:22,000 --> 00:21:25,000
..as the descendants of those
318
00:21:25,000 --> 00:21:27,000
early swimmers get bigger,
319
00:21:27,000 --> 00:21:29,000
stronger and faster.
320
00:21:30,000 --> 00:21:33,000
They shapeshift through countless
321
00:21:33,000 --> 00:21:35,000
iterations until
322
00:21:35,000 --> 00:21:38,000
140 million years later...
323
00:21:41,000 --> 00:21:43,000
{\an8}..they have become...
324
00:21:44,000 --> 00:21:45,000
{\an8}..fish.
325
00:21:51,000 --> 00:21:55,000
This is an ocean
full of powerful bodies.
326
00:21:57,000 --> 00:22:00,000
But here, it's not how many muscles
327
00:22:00,000 --> 00:22:02,000
you've got that counts,
328
00:22:02,000 --> 00:22:04,000
it's how you use them.
329
00:22:08,000 --> 00:22:10,000
Now, there are many forces
330
00:22:10,000 --> 00:22:12,000
shaping evolution.
331
00:22:13,000 --> 00:22:16,000
The need to find food,
the need to find mates.
332
00:22:18,000 --> 00:22:22,000
But there are even greater forces
at play,
333
00:22:22,000 --> 00:22:24,000
those forces which shape
the entire universe.
334
00:22:24,000 --> 00:22:28,000
I'm talking about
the laws of physics.
335
00:22:28,000 --> 00:22:30,000
And when it comes to locomotion,
336
00:22:30,000 --> 00:22:33,000
harnessing these would be key.
337
00:22:33,000 --> 00:22:37,000
And fish have achieved that
with a remarkable innovation,
338
00:22:37,000 --> 00:22:40,000
something that's startling
in its simplicity,
339
00:22:40,000 --> 00:22:43,000
but significant in its importance.
340
00:22:47,000 --> 00:22:49,000
Something that, today,
341
00:22:49,000 --> 00:22:54,000
has helped make fish
the success story of our oceans.
342
00:22:57,000 --> 00:23:00,000
Attached to their
streamlined bodies,
343
00:23:00,000 --> 00:23:02,000
structures of flesh, cartilage
344
00:23:02,000 --> 00:23:04,000
and bone have evolved.
345
00:23:06,000 --> 00:23:08,000
Tools which their muscles
346
00:23:08,000 --> 00:23:13,000
can control, expanding the mechanics
347
00:23:13,000 --> 00:23:15,000
of movement available to them.
348
00:23:18,000 --> 00:23:20,000
They can be gliders,
349
00:23:20,000 --> 00:23:22,000
thrusters,
350
00:23:22,000 --> 00:23:24,000
rudders.
351
00:23:24,000 --> 00:23:28,000
I'm talking about fins.
352
00:23:34,000 --> 00:23:38,000
And 380 million years ago,
353
00:23:38,000 --> 00:23:40,000
the ancestor of the horse
354
00:23:40,000 --> 00:23:43,000
was a fish, with fins like this.
355
00:23:46,000 --> 00:23:49,000
You can see the fin here.
356
00:23:49,000 --> 00:23:50,000
But look at the base.
357
00:23:50,000 --> 00:23:52,000
It's made up of a series of
358
00:23:52,000 --> 00:23:55,000
robust, strong bones
which anchor it to the body,
359
00:23:55,000 --> 00:23:59,000
and they would have been covered
with powerful muscles.
360
00:23:59,000 --> 00:24:01,000
And it's this stalk, or lobe,
361
00:24:01,000 --> 00:24:04,000
which gives this group of fishes
their name.
362
00:24:04,000 --> 00:24:08,000
We call them the lobe-finned fishes.
363
00:24:08,000 --> 00:24:11,000
Now, I've got to be honest with you,
in the open ocean,
364
00:24:11,000 --> 00:24:14,000
this set-up probably didn't
confer them with much of
365
00:24:14,000 --> 00:24:15,000
a competitive advantage,
366
00:24:15,000 --> 00:24:17,000
but under certain circumstances,
367
00:24:17,000 --> 00:24:20,000
it proved to be a real bonus.
368
00:24:30,000 --> 00:24:32,000
This is Onychodus...
369
00:24:34,000 --> 00:24:35,000
..an ancient predator
370
00:24:35,000 --> 00:24:37,000
as big as a crocodile...
371
00:24:39,000 --> 00:24:42,000
..with muscular lobed fins.
372
00:24:46,000 --> 00:24:48,000
Now, its size and weight
373
00:24:48,000 --> 00:24:51,000
should be an advantage,
374
00:24:51,000 --> 00:24:54,000
making Onychodus a formidable foe.
375
00:24:56,000 --> 00:24:57,000
But when it swims...
376
00:25:00,000 --> 00:25:03,000
..the water around it is churned up,
377
00:25:03,000 --> 00:25:04,000
giving the game away.
378
00:25:10,000 --> 00:25:14,000
So how does this ocean giant
catch its dinner?
379
00:25:20,000 --> 00:25:23,000
The answer lies in those lobed fins.
380
00:25:23,000 --> 00:25:27,000
Inside there is a tool
that's just begging to be used,
381
00:25:27,000 --> 00:25:30,000
a tool with enormous potential.
382
00:25:30,000 --> 00:25:32,000
I'm talking about a lever.
383
00:25:38,000 --> 00:25:41,000
You see, the relatively small
distance travelled by my hand
384
00:25:41,000 --> 00:25:47,000
and arm here is magnified out there
at the tip of the oar,
385
00:25:47,000 --> 00:25:49,000
which is moving far further.
386
00:25:56,000 --> 00:25:59,000
{\an8}When it comes to
generating movement,
387
00:25:59,000 --> 00:26:01,000
{\an8}muscles are fantastic,
388
00:26:01,000 --> 00:26:03,000
{\an8}but they do have their limitations.
389
00:26:06,000 --> 00:26:11,000
The lever
is life's great multiplier.
390
00:26:16,000 --> 00:26:19,000
Look, a small amount of force
391
00:26:19,000 --> 00:26:22,000
applied by my arms in the boat
392
00:26:22,000 --> 00:26:24,000
is transferred to the tip of
those oars,
393
00:26:24,000 --> 00:26:29,000
and it allows me to propel
the boat forward.
394
00:26:29,000 --> 00:26:32,000
Not exactly with Olympic prowess,
I have to confess,
395
00:26:32,000 --> 00:26:35,000
but with a degree of efficiency.
396
00:26:41,000 --> 00:26:44,000
And it's thought this same principle
397
00:26:44,000 --> 00:26:46,000
helped this hulking fish
398
00:26:46,000 --> 00:26:48,000
to move with incredible delicacy...
399
00:26:50,000 --> 00:26:52,000
..by doing something
400
00:26:52,000 --> 00:26:54,000
very unfish-like.
401
00:26:59,000 --> 00:27:02,000
Using four of its lobed fins,
402
00:27:02,000 --> 00:27:05,000
along with the physics of levers,
403
00:27:05,000 --> 00:27:08,000
Onychodus turns minimum effort
404
00:27:08,000 --> 00:27:10,000
into maximum movement
405
00:27:10,000 --> 00:27:12,000
and propels itself
406
00:27:12,000 --> 00:27:16,000
stealthily across the seafloor.
407
00:27:30,000 --> 00:27:32,000
Swapping swimming for walking,
408
00:27:32,000 --> 00:27:38,000
it saves its energy for one final,
409
00:27:38,000 --> 00:27:40,000
powerful thrust.
410
00:27:47,000 --> 00:27:51,000
Thanks to its four lobed fins,
411
00:27:51,000 --> 00:27:54,000
Onychodus is a master of the ambush.
412
00:28:00,000 --> 00:28:03,000
So, with skills like these,
413
00:28:03,000 --> 00:28:07,000
you'd expect there to be plenty
of lobe-finned fish in the sea,
414
00:28:07,000 --> 00:28:13,000
{\an8}but today, they have almost entirely
vanished from our waters.
415
00:28:19,000 --> 00:28:21,000
My goodness!
416
00:28:22,000 --> 00:28:25,000
That was a bit of a workout.
417
00:28:25,000 --> 00:28:28,000
Now, look, levers
are very useful in water,
418
00:28:28,000 --> 00:28:32,000
but they could become
even more useful somewhere else.
419
00:28:36,000 --> 00:28:38,000
When fish like Onychodus begin
420
00:28:38,000 --> 00:28:41,000
to use their lobed fins to walk,
421
00:28:41,000 --> 00:28:43,000
rather than swim,
422
00:28:43,000 --> 00:28:46,000
they set off a chain reaction.
423
00:28:52,000 --> 00:28:55,000
Over millions of years...
424
00:28:56,000 --> 00:28:58,000
..the thick bridge of bones
425
00:28:58,000 --> 00:29:01,000
inside those four fins lengthen...
426
00:29:04,000 --> 00:29:06,000
..and the muscles surrounding them
427
00:29:06,000 --> 00:29:08,000
shift and alter...
428
00:29:10,000 --> 00:29:14,000
..creating strong, tough appendages.
429
00:29:15,000 --> 00:29:18,000
No longer fins at all...
430
00:29:20,000 --> 00:29:23,000
..but four levered limbs.
431
00:29:25,000 --> 00:29:29,000
This was the birth of the tetrapods.
432
00:29:31,000 --> 00:29:33,000
And today, there are more than
433
00:29:33,000 --> 00:29:36,000
30,000 species,
434
00:29:36,000 --> 00:29:37,000
inhabiting every continent.
435
00:29:45,000 --> 00:29:48,000
A diverse supergroup,
436
00:29:48,000 --> 00:29:50,000
all descendants of those fish
437
00:29:50,000 --> 00:29:52,000
{\an8}with four lobed fins,
438
00:29:52,000 --> 00:29:55,000
are now putting them to use
439
00:29:55,000 --> 00:29:57,000
in very different ways.
440
00:29:58,000 --> 00:30:01,000
Including the horse.
441
00:30:07,000 --> 00:30:09,000
For many tetrapods today,
442
00:30:09,000 --> 00:30:13,000
moving on land is second nature,
443
00:30:13,000 --> 00:30:17,000
but for their ancestors
crawling out of the sea,
444
00:30:17,000 --> 00:30:19,000
it was a very different story.
445
00:30:22,000 --> 00:30:25,000
Moving from one ecosystem
446
00:30:25,000 --> 00:30:27,000
to another
which is completely different,
447
00:30:27,000 --> 00:30:33,000
requires a painfully slow process
of adaptation.
448
00:30:33,000 --> 00:30:35,000
But the creatures that were making
that transition
449
00:30:35,000 --> 00:30:38,000
looked a little bit like this.
450
00:30:42,000 --> 00:30:44,000
Oh, yes.
451
00:30:46,000 --> 00:30:49,000
Look at that.
452
00:30:49,000 --> 00:30:50,000
That's special.
453
00:30:50,000 --> 00:30:53,000
One of nature's jewels.
454
00:30:53,000 --> 00:30:55,000
Absolutely beautiful.
455
00:30:55,000 --> 00:30:58,000
This is a marbled newt.
456
00:30:58,000 --> 00:31:02,000
You see how it got its name,
with that marbling running down
457
00:31:02,000 --> 00:31:04,000
its back there.
458
00:31:05,000 --> 00:31:07,000
It's an amphibian.
459
00:31:07,000 --> 00:31:11,000
It spends its spring in ponds
going through its breeding cycle
460
00:31:11,000 --> 00:31:13,000
and then at the end of summer,
it emerges onto land,
461
00:31:13,000 --> 00:31:15,000
where it spends
the rest of the year.
462
00:31:15,000 --> 00:31:20,000
But, of course, it's gone through
millions of years of evolution,
463
00:31:20,000 --> 00:31:23,000
which allow it to exploit
the best of both worlds -
464
00:31:23,000 --> 00:31:26,000
the wet and the dry.
465
00:31:26,000 --> 00:31:28,000
But what about its movement?
466
00:31:28,000 --> 00:31:31,000
Well, in the ponds, it's
a fairly good swimmer, to be fair.
467
00:31:31,000 --> 00:31:33,000
What about on land?
468
00:31:33,000 --> 00:31:35,000
Let's give it a go.
469
00:31:44,000 --> 00:31:47,000
They're tentative, they're slow,
470
00:31:47,000 --> 00:31:49,000
they're laborious,
they're calculated.
471
00:31:49,000 --> 00:31:52,000
Their little bodies
bending from side to side,
472
00:31:52,000 --> 00:31:54,000
as they rather lethargically
473
00:31:54,000 --> 00:31:56,000
move through the environment.
474
00:31:57,000 --> 00:32:00,000
I've never seen a newt
galloping or frolicking.
475
00:32:00,000 --> 00:32:02,000
I'm never going to. But this does
476
00:32:02,000 --> 00:32:05,000
tell us something very important.
477
00:32:07,000 --> 00:32:10,000
Movement on land is hard.
478
00:32:10,000 --> 00:32:11,000
Very hard.
479
00:32:18,000 --> 00:32:22,000
This newt can get away with having
480
00:32:22,000 --> 00:32:25,000
four left feet because in a pinch,
481
00:32:25,000 --> 00:32:28,000
it can retreat to a habitat
482
00:32:28,000 --> 00:32:30,000
it finds easier to negotiate.
483
00:32:37,000 --> 00:32:41,000
But 350 million years ago,
484
00:32:41,000 --> 00:32:43,000
if the ancestors of the horse
485
00:32:43,000 --> 00:32:44,000
were to pursue a life
486
00:32:44,000 --> 00:32:47,000
solely on solid ground,
487
00:32:47,000 --> 00:32:51,000
they would need to be
far more coordinated.
488
00:32:51,000 --> 00:32:56,000
And the answer to their coordination
conundrum came, once again,
489
00:32:56,000 --> 00:32:58,000
with an evolutionary innovation
490
00:32:58,000 --> 00:33:02,000
from the ever-adaptable muscle.
491
00:33:02,000 --> 00:33:06,000
Inside almost every muscle
in my body,
492
00:33:06,000 --> 00:33:09,000
I have something called
a stretch sensor.
493
00:33:09,000 --> 00:33:13,000
And stretch sensors
are highly specialised muscle fibres
494
00:33:13,000 --> 00:33:17,000
that are constantly monitoring
how and when
495
00:33:17,000 --> 00:33:19,000
those muscles are moving.
496
00:33:19,000 --> 00:33:24,000
The key thing is that they are all
linked together in a complex web,
497
00:33:24,000 --> 00:33:27,000
so each individual muscle knows
498
00:33:27,000 --> 00:33:30,000
exactly when every...other muscle
499
00:33:30,000 --> 00:33:34,000
is moving. Now, despite the fact
that this is an incredibly
500
00:33:34,000 --> 00:33:39,000
complicated system, I bet that
you've never even thought about it,
501
00:33:39,000 --> 00:33:41,000
and that's because
you don't have to,
502
00:33:41,000 --> 00:33:43,000
despite the fact that it's crucial
503
00:33:43,000 --> 00:33:46,000
for every single move that we make.
504
00:33:55,000 --> 00:33:59,000
Tiny stretch sensors allow
the muscles to communicate
505
00:33:59,000 --> 00:34:02,000
with the central nervous system,
506
00:34:02,000 --> 00:34:05,000
giving us and most living tetrapods
507
00:34:05,000 --> 00:34:07,000
the ability to co-ordinate movement
508
00:34:07,000 --> 00:34:09,000
with astonishing precision.
509
00:34:09,000 --> 00:34:13,000
Often, faster than you can think.
510
00:34:20,000 --> 00:34:21,000
Look at that.
511
00:34:28,000 --> 00:34:29,000
Just look at the legs there.
512
00:34:29,000 --> 00:34:33,000
Every part of them
is moving independently,
513
00:34:33,000 --> 00:34:35,000
in isolation, at the same time.
514
00:34:35,000 --> 00:34:38,000
And then the weight -
515
00:34:38,000 --> 00:34:42,000
that's got to be balanced
between all four feet.
516
00:34:42,000 --> 00:34:44,000
And running down those legs -
517
00:34:44,000 --> 00:34:47,000
just going to speed it up,
look at that -
518
00:34:47,000 --> 00:34:50,000
are ripples of muscles.
519
00:34:50,000 --> 00:34:52,000
That's the glutes, that's the quads,
520
00:34:52,000 --> 00:34:56,000
that's the hamstrings,
all working in unison.
521
00:34:59,000 --> 00:35:02,000
Without these little gizmos,
522
00:35:02,000 --> 00:35:04,000
these stretch sensors
hiding in muscles
523
00:35:04,000 --> 00:35:07,000
and the complex network
that joins them all together,
524
00:35:07,000 --> 00:35:11,000
animals with bodies like this simply
would not have been able to evolve.
525
00:35:15,000 --> 00:35:18,000
It was down to this innovation
526
00:35:18,000 --> 00:35:19,000
that animal bodies could become
527
00:35:19,000 --> 00:35:22,000
radically more coordinated,
528
00:35:22,000 --> 00:35:25,000
and those tiny little bones,
once hidden in those fish's fins,
529
00:35:25,000 --> 00:35:27,000
could really come into their own.
530
00:35:29,000 --> 00:35:33,000
Those fully terrestrial animals
531
00:35:33,000 --> 00:35:38,000
could put one foot in front of
the other with extreme precision...
532
00:35:40,000 --> 00:35:42,000
..and this was a game-changer.
533
00:35:47,000 --> 00:35:50,000
Time for us to motor on.
534
00:35:53,000 --> 00:35:56,000
Over the next 300 million years,
535
00:35:56,000 --> 00:35:59,000
the tetrapods
scattered across the Earth.
536
00:36:05,000 --> 00:36:08,000
Whilst life faced
some cosmic curveballs...
537
00:36:10,000 --> 00:36:12,000
..it was never fully derailed.
538
00:36:14,000 --> 00:36:16,000
And evolution carried on...
539
00:36:19,000 --> 00:36:21,000
..tumbling us...
540
00:36:24,000 --> 00:36:26,000
{\an8}..into a new world...
541
00:36:30,000 --> 00:36:32,000
{\an8}..where the way you move...
542
00:36:33,000 --> 00:36:37,000
..can be a matter of life
543
00:36:37,000 --> 00:36:39,000
and death.
544
00:36:44,000 --> 00:36:46,000
This is Phenacodus.
545
00:36:54,000 --> 00:36:57,000
Life looks pretty serene,
546
00:36:57,000 --> 00:37:00,000
but Phenacodus must constantly
547
00:37:00,000 --> 00:37:04,000
be on guard, because this world
548
00:37:04,000 --> 00:37:06,000
is full of expert movers...
549
00:37:06,000 --> 00:37:08,000
BRANCH SNAPS
550
00:37:08,000 --> 00:37:09,000
..whose bodies...
551
00:37:11,000 --> 00:37:14,000
..have evolved for the chase.
552
00:37:18,000 --> 00:37:20,000
When the hunt is on...
GROWLING
553
00:37:20,000 --> 00:37:23,000
..surging adrenaline,
thumping hearts
554
00:37:23,000 --> 00:37:26,000
and straining muscles
will only take you so far.
555
00:37:31,000 --> 00:37:33,000
Faced with a situation it can't
556
00:37:33,000 --> 00:37:34,000
muscle its way out of...
557
00:37:36,000 --> 00:37:38,000
..the secret to Phenacodus's
558
00:37:38,000 --> 00:37:43,000
survival lies in its feet.
559
00:37:47,000 --> 00:37:50,000
Come on, Siddy! Nance, come on!
560
00:37:50,000 --> 00:37:51,000
DOG BARKS
561
00:37:56,000 --> 00:38:00,000
Do you know, sometimes, people say,
"Why poodles?
562
00:38:00,000 --> 00:38:03,000
"Why poodles?" they say.
And I facetiously reply,
563
00:38:03,000 --> 00:38:05,000
"Are there other breeds of dog?"
564
00:38:05,000 --> 00:38:06,000
I mean, look at them.
565
00:38:06,000 --> 00:38:09,000
Boundless energy, incredibly loyal,
566
00:38:09,000 --> 00:38:11,000
and they can also help us
567
00:38:11,000 --> 00:38:14,000
with an important part of our story.
568
00:38:14,000 --> 00:38:15,000
You see, hidden beneath
569
00:38:15,000 --> 00:38:18,000
this curly fur here is a crucial
570
00:38:18,000 --> 00:38:21,000
step change in evolution.
571
00:38:21,000 --> 00:38:24,000
Now, I don't need to tell you
about my foot and leg,
572
00:38:24,000 --> 00:38:26,000
you've got your own.
Starts off at the toe,
573
00:38:26,000 --> 00:38:28,000
goes across the foot to the ankle,
574
00:38:28,000 --> 00:38:32,000
then you've got the shin,
the knee, the thigh.
575
00:38:32,000 --> 00:38:34,000
{\an8}We put our feet down
576
00:38:34,000 --> 00:38:35,000
{\an8}onto the ground, we plant them
577
00:38:35,000 --> 00:38:38,000
{\an8}flat on the ground like that.
578
00:38:38,000 --> 00:38:39,000
{\an8}We're what we call
579
00:38:39,000 --> 00:38:43,000
plantigrade animals. It's quite
an efficient way of walking.
580
00:38:43,000 --> 00:38:46,000
Nancy, on the other hand,
is altogether different.
581
00:38:46,000 --> 00:38:48,000
Let's take a look at her
back leg here.
582
00:38:48,000 --> 00:38:51,000
{\an8}You see, her toes stretch
583
00:38:51,000 --> 00:38:52,000
{\an8}from here to here.
584
00:38:52,000 --> 00:38:54,000
{\an8}The rest of her foot bones
585
00:38:54,000 --> 00:38:56,000
{\an8}all the way up to here, which looks
586
00:38:56,000 --> 00:38:57,000
{\an8}like a backward-pointing knee,
587
00:38:57,000 --> 00:39:00,000
{\an8}but this is, in fact, her ankle.
588
00:39:00,000 --> 00:39:02,000
Her knee is all the way
589
00:39:02,000 --> 00:39:04,000
up here. So Nancy
590
00:39:04,000 --> 00:39:06,000
{\an8}is effectively standing up
591
00:39:06,000 --> 00:39:09,000
{\an8}on her toe bones.
592
00:39:09,000 --> 00:39:13,000
She's a digitigrade animal,
593
00:39:13,000 --> 00:39:15,000
and that's altogether different.
594
00:39:15,000 --> 00:39:18,000
It means that you move in
a very different way, doesn't it?
595
00:39:18,000 --> 00:39:19,000
Shall we show them?
596
00:39:19,000 --> 00:39:22,000
Come on, let's go. Come on.
597
00:39:30,000 --> 00:39:33,000
Right, Sid, Nancy.
598
00:39:33,000 --> 00:39:35,000
Let's see them in action.
599
00:39:35,000 --> 00:39:36,000
{\an8}BARKING
600
00:39:41,000 --> 00:39:44,000
{\an8}BARKING
Woo-hoo-hoo!
601
00:39:44,000 --> 00:39:46,000
Look at them go! You see,
602
00:39:46,000 --> 00:39:50,000
this change in anatomy
allows the leg to become longer,
603
00:39:50,000 --> 00:39:52,000
the stride to become longer,
604
00:39:52,000 --> 00:39:55,000
and more efficient use of
all of that elastic energy
605
00:39:55,000 --> 00:39:58,000
stored in the muscles and tendons
606
00:39:58,000 --> 00:40:00,000
above their ankle.
607
00:40:00,000 --> 00:40:01,000
Look at that!
608
00:40:01,000 --> 00:40:03,000
{\an8}Bouncing about.
609
00:40:03,000 --> 00:40:04,000
{\an8}BARKING
610
00:40:04,000 --> 00:40:08,000
Alacrity, agility.
611
00:40:08,000 --> 00:40:10,000
Critically, speed.
612
00:40:10,000 --> 00:40:13,000
That is a happy poodle.
613
00:40:14,000 --> 00:40:17,000
And, you know, this adaptation
has occurred a number of times
614
00:40:17,000 --> 00:40:21,000
in terrestrial animals.
But having said that,
615
00:40:21,000 --> 00:40:24,000
if you really want to be a creature
living life in the fast lane,
616
00:40:24,000 --> 00:40:29,000
evolution can offer you
one more gear.
617
00:40:29,000 --> 00:40:31,000
Siddy, Nance, come on! Come on!
618
00:40:34,000 --> 00:40:38,000
When it comes to speed and
efficiency, plantigrade -
619
00:40:38,000 --> 00:40:41,000
that's us -
will get you from A to B.
620
00:40:41,000 --> 00:40:44,000
Digitigrade - like my dogs -
621
00:40:44,000 --> 00:40:46,000
ups the revs.
622
00:40:48,000 --> 00:40:51,000
But 56 million years ago,
623
00:40:51,000 --> 00:40:55,000
Phenacodus was
on the verge of something new.
624
00:40:56,000 --> 00:41:00,000
Not just bouncing
on the balls of its feet,
625
00:41:00,000 --> 00:41:05,000
but pushing off from the
very tips of its toes...
626
00:41:08,000 --> 00:41:11,000
..lengthening its stride
even further.
627
00:41:12,000 --> 00:41:16,000
So future generations
take the concept...
628
00:41:17,000 --> 00:41:18,000
..and run with it.
629
00:41:23,000 --> 00:41:25,000
As bones elongate
630
00:41:25,000 --> 00:41:27,000
and muscles bulk up...
631
00:41:28,000 --> 00:41:30,000
..they spend more
632
00:41:30,000 --> 00:41:32,000
and more time on tiptoe...
633
00:41:35,000 --> 00:41:37,000
..and in the process...
634
00:41:38,000 --> 00:41:40,000
..find the most efficiency
635
00:41:40,000 --> 00:41:42,000
in trading many toes
636
00:41:42,000 --> 00:41:45,000
for one large,
637
00:41:45,000 --> 00:41:47,000
powerful shock absorber.
638
00:41:52,000 --> 00:41:54,000
Look at this.
639
00:41:54,000 --> 00:41:57,000
This is clearly a cast
640
00:41:57,000 --> 00:41:59,000
of a fossil of a hoof.
641
00:41:59,000 --> 00:42:03,000
A hoof at the end of
a very long leg.
642
00:42:03,000 --> 00:42:07,000
A leg that's clearly
all about movement.
643
00:42:07,000 --> 00:42:11,000
A leg, though, that is surprisingly
different than ours.
644
00:42:11,000 --> 00:42:13,000
You see, essentially, it's foot
645
00:42:13,000 --> 00:42:15,000
all the way from here to here.
646
00:42:15,000 --> 00:42:18,000
This is the equivalent of our ankle.
647
00:42:18,000 --> 00:42:20,000
The bone here would be like those
in the sole of our foot.
648
00:42:20,000 --> 00:42:22,000
And down here,
649
00:42:22,000 --> 00:42:26,000
it's balancing on a single tiptoe.
650
00:42:26,000 --> 00:42:29,000
The hoof itself
would have been made of keratin,
651
00:42:29,000 --> 00:42:31,000
just like our fingernail.
652
00:42:31,000 --> 00:42:33,000
And also, what's interesting
is at the other end,
653
00:42:33,000 --> 00:42:36,000
the front legs weren't attached
to the skeleton.
654
00:42:36,000 --> 00:42:37,000
They were embedded
655
00:42:37,000 --> 00:42:40,000
in a heavy mass of powerful muscle,
656
00:42:40,000 --> 00:42:45,000
and this gave it the capacity
for a greater stride.
657
00:42:45,000 --> 00:42:47,000
You see this groove here?
658
00:42:47,000 --> 00:42:49,000
Running down here
would have been a tendon,
659
00:42:49,000 --> 00:42:51,000
perhaps half a metre long,
660
00:42:51,000 --> 00:42:54,000
a giant elastic band.
661
00:42:54,000 --> 00:42:57,000
But it is a leg with compromises.
662
00:42:57,000 --> 00:43:00,000
I mean, you can't pick anything up
with a hoof,
663
00:43:00,000 --> 00:43:01,000
you can't manipulate anything.
664
00:43:01,000 --> 00:43:04,000
It's lost all dexterity,
665
00:43:04,000 --> 00:43:06,000
at the expense of speed.
666
00:43:08,000 --> 00:43:12,000
This three-million-year-old hoof
667
00:43:12,000 --> 00:43:15,000
tells us of the arrival
668
00:43:15,000 --> 00:43:18,000
of a new group of animals.
669
00:43:18,000 --> 00:43:22,000
Animals we call Equus.
670
00:43:34,000 --> 00:43:36,000
{\an8}These single-hoofed mammals
671
00:43:36,000 --> 00:43:39,000
{\an8}first evolved on the plains of
North America...
672
00:43:41,000 --> 00:43:44,000
..before spreading across the globe.
673
00:43:46,000 --> 00:43:49,000
Among them
674
00:43:49,000 --> 00:43:52,000
was one remarkable species.
675
00:43:54,000 --> 00:43:57,000
{\an8}Equus ferus.
676
00:44:00,000 --> 00:44:04,000
Known to you and I as the horse.
677
00:44:10,000 --> 00:44:12,000
{\an8}Its body shaped
678
00:44:12,000 --> 00:44:14,000
{\an8}generation after generation...
679
00:44:19,000 --> 00:44:22,000
{\an8}..by the evolutionary drive to move.
680
00:44:25,000 --> 00:44:28,000
700 muscles, passed down
681
00:44:28,000 --> 00:44:31,000
over half a billion years,
682
00:44:31,000 --> 00:44:33,000
from a pioneer
who changed the world.
683
00:44:33,000 --> 00:44:37,000
A huge heart, with an ancient beat,
684
00:44:37,000 --> 00:44:40,000
that began deep beneath the waves.
685
00:44:40,000 --> 00:44:43,000
Long levered limbs
686
00:44:43,000 --> 00:44:46,000
that once helped a fish to walk...
687
00:44:48,000 --> 00:44:50,000
..and four large hooves,
688
00:44:50,000 --> 00:44:52,000
the legacy of ancestors
689
00:44:52,000 --> 00:44:56,000
who had to run for their lives.
690
00:44:57,000 --> 00:45:00,000
But there's one final twist
691
00:45:00,000 --> 00:45:03,000
in the story of the horse,
692
00:45:03,000 --> 00:45:05,000
because Equus ferus
693
00:45:05,000 --> 00:45:07,000
was about to encounter
694
00:45:07,000 --> 00:45:09,000
a new force of evolution.
695
00:45:17,000 --> 00:45:19,000
Another species
696
00:45:19,000 --> 00:45:22,000
on an evolutionary
journey of its own.
697
00:45:22,000 --> 00:45:24,000
A bipedal tetrapod,
698
00:45:24,000 --> 00:45:27,000
with opposable thumbs,
699
00:45:27,000 --> 00:45:31,000
and an overinflated
sense of self-worth.
700
00:45:48,000 --> 00:45:51,000
4,000 years ago, Homo sapiens -
701
00:45:51,000 --> 00:45:53,000
that's us - inhabited
702
00:45:53,000 --> 00:45:55,000
much of the planet.
703
00:45:55,000 --> 00:45:56,000
HORSE WHINNIES
704
00:45:56,000 --> 00:45:59,000
We had city states and agriculture.
705
00:45:59,000 --> 00:46:02,000
Empires were beginning to grow.
706
00:46:04,000 --> 00:46:07,000
And at this time,
in Europe and Asia,
707
00:46:07,000 --> 00:46:09,000
we begin to see evidence
708
00:46:09,000 --> 00:46:11,000
of a growing relationship
709
00:46:11,000 --> 00:46:13,000
between horses
710
00:46:13,000 --> 00:46:15,000
and humans.
711
00:46:18,000 --> 00:46:22,000
Now, no-one is exactly sure
how the first horse was tamed.
712
00:46:22,000 --> 00:46:25,000
Maybe someone caught
one of those wild horses,
713
00:46:25,000 --> 00:46:28,000
took it into captivity,
gave it shelter, food,
714
00:46:28,000 --> 00:46:32,000
cared for it, loved it
and trained it.
715
00:46:32,000 --> 00:46:35,000
But what we do know is that
in pretty short time,
716
00:46:35,000 --> 00:46:39,000
we took these strong, efficient,
powerful animals
717
00:46:39,000 --> 00:46:43,000
and turned them into
our perfect companions.
718
00:46:43,000 --> 00:46:46,000
And, you know,
we didn't just tame them.
719
00:46:46,000 --> 00:46:49,000
Over generation after generation,
we bred them,
720
00:46:49,000 --> 00:46:52,000
choosing those characteristics
which favoured the way
721
00:46:52,000 --> 00:46:55,000
we wanted horses to be.
722
00:46:55,000 --> 00:46:58,000
So in the end,
we took the wild horse
723
00:46:58,000 --> 00:47:01,000
and we turned it into the workhorse.
724
00:47:14,000 --> 00:47:16,000
We chose the strongest.
725
00:47:18,000 --> 00:47:19,000
We chose the most powerful.
726
00:47:21,000 --> 00:47:24,000
But we also chose the friendliest,
727
00:47:24,000 --> 00:47:26,000
the most amenable.
728
00:47:29,000 --> 00:47:32,000
And for better or for worse,
729
00:47:32,000 --> 00:47:34,000
over the generations,
730
00:47:34,000 --> 00:47:36,000
the horse was altered.
731
00:47:40,000 --> 00:47:42,000
The ancestors of the modern horse
732
00:47:42,000 --> 00:47:43,000
were a pretty wild bunch.
733
00:47:45,000 --> 00:47:47,000
Diverse not only in terms of
their physical appearance,
734
00:47:47,000 --> 00:47:50,000
but also, their genetic make-up.
735
00:47:50,000 --> 00:47:52,000
And about 4,000 years ago,
736
00:47:52,000 --> 00:47:55,000
we see two gene variants appear.
737
00:47:55,000 --> 00:47:56,000
HORSE WHINNIES
738
00:47:56,000 --> 00:47:59,000
Now, one of those appears to
make them less aggressive,
739
00:47:59,000 --> 00:48:01,000
more manageable.
740
00:48:03,000 --> 00:48:06,000
And the other, which appears
to give them a stronger back,
741
00:48:06,000 --> 00:48:09,000
making them easier to ride.
742
00:48:09,000 --> 00:48:11,000
Now, what's interesting is that
743
00:48:11,000 --> 00:48:13,000
within the space of
just a few hundred years,
744
00:48:13,000 --> 00:48:15,000
we'd spread those gene variants
745
00:48:15,000 --> 00:48:18,000
throughout the population.
746
00:48:20,000 --> 00:48:22,000
The wild horse was effectively gone.
747
00:48:22,000 --> 00:48:25,000
We had one global species,
748
00:48:25,000 --> 00:48:28,000
selected by humans.
749
00:48:28,000 --> 00:48:29,000
You.
750
00:48:29,000 --> 00:48:33,000
Yes. I know.
751
00:48:33,000 --> 00:48:35,000
It wasn't my fault.
752
00:48:35,000 --> 00:48:36,000
I wasn't around then.
753
00:48:48,000 --> 00:48:52,000
Today, the horse
goes by a new name.
754
00:48:53,000 --> 00:48:57,000
Equus ferus caballus.
755
00:48:57,000 --> 00:48:59,000
The domestic horse.
756
00:49:01,000 --> 00:49:03,000
Our relationship is a special one.
757
00:49:05,000 --> 00:49:07,000
Together, we've travelled to
758
00:49:07,000 --> 00:49:09,000
every corner of the globe.
759
00:49:11,000 --> 00:49:12,000
Step by step...
760
00:49:14,000 --> 00:49:15,000
..and side by side.
761
00:49:21,000 --> 00:49:23,000
We often think of evolution
762
00:49:23,000 --> 00:49:25,000
as a battle between species,
763
00:49:25,000 --> 00:49:27,000
a game of winners and losers,
764
00:49:27,000 --> 00:49:29,000
a game of survival of the fittest.
765
00:49:29,000 --> 00:49:32,000
But very occasionally,
species come together
766
00:49:32,000 --> 00:49:36,000
and the result is greater than
the sum of their parts.
767
00:49:36,000 --> 00:49:40,000
Now, there's no doubt we played
a hugely instrumental role
768
00:49:40,000 --> 00:49:42,000
in the evolution of the horse,
769
00:49:42,000 --> 00:49:45,000
but then the horse has had
an impact on us too,
770
00:49:45,000 --> 00:49:50,000
because without this remarkable
animal as our greatest partner,
771
00:49:50,000 --> 00:49:54,000
we simply wouldn't be
the species we are today.
772
00:49:58,000 --> 00:50:01,000
The horse's evolutionary journey
773
00:50:01,000 --> 00:50:03,000
is just one thread
774
00:50:03,000 --> 00:50:06,000
in an extraordinary tapestry...
775
00:50:07,000 --> 00:50:11,000
..that weaves together every animal,
776
00:50:11,000 --> 00:50:14,000
in fact, every living thing
777
00:50:14,000 --> 00:50:16,000
on our planet.
778
00:50:17,000 --> 00:50:20,000
It's taken four billion years
779
00:50:20,000 --> 00:50:23,000
to get here, but, boy,
780
00:50:23,000 --> 00:50:26,000
has life come a very, very long way!
781
00:50:29,000 --> 00:50:32,000
From the cell that began it all...
782
00:50:34,000 --> 00:50:36,000
..to sex...
783
00:50:37,000 --> 00:50:39,000
..to competition...
784
00:50:40,000 --> 00:50:42,000
..to predation and protection.
785
00:50:49,000 --> 00:50:52,000
From the oceans to the land
786
00:50:52,000 --> 00:50:56,000
and, for some, back again.
787
00:50:59,000 --> 00:51:03,000
For others, onwards to the skies.
788
00:51:05,000 --> 00:51:08,000
There was a bum
that changed the world.
789
00:51:09,000 --> 00:51:11,000
There were jaws, limbs,
790
00:51:11,000 --> 00:51:14,000
hearts and minds.
791
00:51:14,000 --> 00:51:17,000
Minds which have evolved to sense,
792
00:51:17,000 --> 00:51:20,000
to move, to love,
793
00:51:20,000 --> 00:51:21,000
to contemplate...
794
00:51:24,000 --> 00:51:27,000
..and, in our case,
795
00:51:27,000 --> 00:51:28,000
to begin to understand
796
00:51:28,000 --> 00:51:31,000
our own origins.
797
00:51:36,000 --> 00:51:39,000
A journey of knowledge
798
00:51:39,000 --> 00:51:41,000
that we're still on today.
799
00:51:44,000 --> 00:51:46,000
There's an outdated view,
800
00:51:46,000 --> 00:51:48,000
a mistaken idea,
801
00:51:48,000 --> 00:51:53,000
that we humans are the
be-all and end-all of evolution.
802
00:51:53,000 --> 00:51:56,000
That everything we've explored,
everything we've shown you
803
00:51:56,000 --> 00:52:02,000
in this series was just about
making us the perfect organism,
804
00:52:02,000 --> 00:52:04,000
the paragon of life on Earth.
805
00:52:04,000 --> 00:52:07,000
But it's simply not true.
806
00:52:07,000 --> 00:52:10,000
We're not perfect
and we weren't made.
807
00:52:10,000 --> 00:52:13,000
We've been shaped by
exactly the same forces
808
00:52:13,000 --> 00:52:19,000
that have shaped every organism
that's ever lived on this planet.
809
00:52:19,000 --> 00:52:21,000
And through a startling
twist of fate,
810
00:52:21,000 --> 00:52:24,000
we are now having a profound effect
811
00:52:24,000 --> 00:52:26,000
on evolution ourselves.
812
00:52:26,000 --> 00:52:29,000
A dramatic, rapid and scary one
813
00:52:29,000 --> 00:52:32,000
because of what we're doing
to our environment
814
00:52:32,000 --> 00:52:38,000
and because we're driving
a massive extinction event.
815
00:52:38,000 --> 00:52:43,000
Now, evolution
does feast on extinction.
816
00:52:43,000 --> 00:52:47,000
It loves the opportunities,
the vacancies.
817
00:52:47,000 --> 00:52:50,000
So whatever we do now,
life will go on.
818
00:52:50,000 --> 00:52:54,000
Life will be bright,
life will be beautiful,
819
00:52:54,000 --> 00:52:57,000
life will be wonderful.
820
00:52:57,000 --> 00:53:01,000
But in evolutionary terms,
what about us?
821
00:53:01,000 --> 00:53:04,000
Could we become shorter,
822
00:53:04,000 --> 00:53:06,000
slower, more short-sighted?
823
00:53:06,000 --> 00:53:10,000
Might we become smarter,
more stupid?
824
00:53:11,000 --> 00:53:16,000
I don't think it really matters
about our anatomy at this point.
825
00:53:17,000 --> 00:53:20,000
I think what matters
is how we think,
826
00:53:20,000 --> 00:53:25,000
imagine and create our way
out of our situation.
827
00:53:26,000 --> 00:53:31,000
I think that what needs to be
driving human evolution right now...
828
00:53:33,000 --> 00:53:34,000
..is hope.
829
00:53:57,000 --> 00:53:58,000
But before we go...
830
00:54:01,000 --> 00:54:03,000
..how did we bring the story
831
00:54:03,000 --> 00:54:05,000
of evolution to life?
832
00:54:08,000 --> 00:54:10,000
The way that one animal,
833
00:54:10,000 --> 00:54:11,000
over millions of years,
834
00:54:11,000 --> 00:54:14,000
can transform into something
radically different
835
00:54:14,000 --> 00:54:17,000
was once a mystery lost to time.
836
00:54:19,000 --> 00:54:21,000
If we think about a book,
we have lots of different pages
837
00:54:21,000 --> 00:54:23,000
that tell us the story
from start to finish.
838
00:54:24,000 --> 00:54:27,000
However, with evolution and fossils,
some of those pages are missing.
839
00:54:29,000 --> 00:54:31,000
But occasionally, evidence
840
00:54:31,000 --> 00:54:33,000
is unearthed of the process
841
00:54:33,000 --> 00:54:38,000
in action. In 2004, palaeontologists
842
00:54:38,000 --> 00:54:40,000
in the Canadian Arctic
843
00:54:40,000 --> 00:54:43,000
discovered a ground-breaking fossil.
844
00:54:43,000 --> 00:54:45,000
So this is a cast of Tiktaalik.
845
00:54:45,000 --> 00:54:49,000
Now, Tiktaalik lived about
375 million years ago,
846
00:54:49,000 --> 00:54:51,000
and it's got the scales very much
847
00:54:51,000 --> 00:54:53,000
like modern-day fish have today.
848
00:54:53,000 --> 00:54:56,000
And what's quite unusual
is that it actually has a neck.
849
00:54:56,000 --> 00:54:58,000
{\an8}And these bones
that are around there,
850
00:54:58,000 --> 00:54:59,000
{\an8}these are the sort of collar bone
851
00:54:59,000 --> 00:55:01,000
{\an8}or shoulder girdle. It looks like
852
00:55:01,000 --> 00:55:03,000
a cross between
a fish and an amphibian,
853
00:55:03,000 --> 00:55:06,000
and that's because
that's exactly what it is.
854
00:55:06,000 --> 00:55:08,000
{\an8}Tiktaalik was really this kind of
855
00:55:08,000 --> 00:55:10,000
{\an8}unique snapshot in evolutionary time
856
00:55:10,000 --> 00:55:12,000
{\an8}at this key moment
857
00:55:12,000 --> 00:55:14,000
{\an8}for the water-to-land transition.
858
00:55:15,000 --> 00:55:16,000
{\an8}So it's a perfect example of
859
00:55:16,000 --> 00:55:18,000
{\an8}a transitional fossil.
860
00:55:18,000 --> 00:55:20,000
Transitional fossils
are incredibly rare.
861
00:55:21,000 --> 00:55:23,000
{\an8}They play the really important role
of filling those gaps
862
00:55:23,000 --> 00:55:26,000
{\an8}between morphologies
that we kind of know are there,
863
00:55:26,000 --> 00:55:28,000
{\an8}but we don't really know exactly
864
00:55:28,000 --> 00:55:30,000
{\an8}what they might have looked like.
865
00:55:30,000 --> 00:55:33,000
{\an8}Transitional fossils represent
866
00:55:33,000 --> 00:55:35,000
{\an8}just one out of millions,
867
00:55:35,000 --> 00:55:37,000
possibly billions, of individuals
868
00:55:37,000 --> 00:55:39,000
that, over generations,
869
00:55:39,000 --> 00:55:41,000
contribute to evolutionary change.
870
00:55:41,000 --> 00:55:44,000
Coming up with a way
to illustrate this
871
00:55:44,000 --> 00:55:46,000
posed a huge challenge
872
00:55:46,000 --> 00:55:49,000
{\an8}to the visual effects team
behind the series.
873
00:55:49,000 --> 00:55:51,000
{\an8}Evolution does not move in
a straight line,
874
00:55:51,000 --> 00:55:54,000
{\an8}because it is purely opportunistic
875
00:55:54,000 --> 00:55:55,000
{\an8}and slightly haphazard.
876
00:55:55,000 --> 00:55:58,000
It's tinkering. It's messing with
what's already there,
877
00:55:58,000 --> 00:56:00,000
rather than kind of always
878
00:56:00,000 --> 00:56:03,000
necessarily inventing something
from scratch.
879
00:56:03,000 --> 00:56:05,000
It's all about
a great grand experiment
880
00:56:05,000 --> 00:56:07,000
and just seeing what happens.
881
00:56:08,000 --> 00:56:11,000
The team spent thousands of hours
882
00:56:11,000 --> 00:56:12,000
crafting and animating
883
00:56:12,000 --> 00:56:14,000
computer-generated models
884
00:56:14,000 --> 00:56:16,000
to bring ancient animals
885
00:56:16,000 --> 00:56:17,000
back to life.
886
00:56:17,000 --> 00:56:19,000
But to illustrate the randomness
887
00:56:19,000 --> 00:56:22,000
and variation seen as life evolves,
888
00:56:22,000 --> 00:56:25,000
they needed to experiment.
889
00:56:25,000 --> 00:56:28,000
After consulting scientists
to accurately model
890
00:56:28,000 --> 00:56:30,000
the key evolutionary changes,
891
00:56:30,000 --> 00:56:32,000
they used generative AI software
892
00:56:32,000 --> 00:56:36,000
to create hundreds of variations,
893
00:56:36,000 --> 00:56:39,000
representing countless generations.
894
00:56:39,000 --> 00:56:42,000
And by hand-selecting and merging
895
00:56:42,000 --> 00:56:44,000
the best results with their original
896
00:56:44,000 --> 00:56:46,000
animations, they were able
897
00:56:46,000 --> 00:56:48,000
to condense millions of years
898
00:56:48,000 --> 00:56:49,000
of evolution...
899
00:56:49,000 --> 00:56:51,000
Look at that! There's bones inside!
900
00:56:51,000 --> 00:56:52,000
No way!
901
00:56:52,000 --> 00:56:55,000
..into a matter of seconds.
902
00:56:55,000 --> 00:56:56,000
In reality, this would take
903
00:56:56,000 --> 00:56:58,000
millions of years.
904
00:57:00,000 --> 00:57:01,000
This is a fantastic way
905
00:57:01,000 --> 00:57:04,000
to illustrate the evolution of form.
906
00:57:04,000 --> 00:57:06,000
This is basically how I imagine it
playing out in my head.
907
00:57:17,000 --> 00:57:18,000
This series has been over
908
00:57:18,000 --> 00:57:21,000
four billion years in the making...
909
00:57:22,000 --> 00:57:24,000
..and as a certain Charles Darwin
910
00:57:24,000 --> 00:57:26,000
once wrote,
911
00:57:26,000 --> 00:57:29,000
"From so simple a beginning
912
00:57:29,000 --> 00:57:31,000
"endless forms most beautiful
913
00:57:31,000 --> 00:57:34,000
"and most wonderful have been,
914
00:57:34,000 --> 00:57:37,000
"and are being evolved."
915
00:57:37,000 --> 00:57:39,000
One of the big key life lessons that
916
00:57:39,000 --> 00:57:41,000
I've learned from studying evolution
917
00:57:41,000 --> 00:57:44,000
is that change is constant
918
00:57:44,000 --> 00:57:46,000
and change is the norm. So things
919
00:57:46,000 --> 00:57:48,000
have always changed and will always
920
00:57:48,000 --> 00:57:49,000
continue to change, and life
921
00:57:49,000 --> 00:57:50,000
will always continue to adapt.
922
00:57:53,000 --> 00:57:55,000
That's how it's always been,
923
00:57:55,000 --> 00:57:56,000
and there's no reason to believe
924
00:57:56,000 --> 00:57:58,000
that's not how
it's going to continue to be.
925
00:58:11,000 --> 00:58:14,000
Do you want to know how an elephant
is related to a clownfish?
926
00:58:14,000 --> 00:58:18,000
Discover more in a poster
from the Open University on
927
00:58:18,000 --> 00:58:20,000
{\an8}the tree of life.
To get your free copy,
928
00:58:20,000 --> 00:58:23,000
{\an8}scan the QR code
on-screen or ring...
929
00:58:26,000 --> 00:58:28,000
{\an8}..or visit...
67134
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