Original subtitles

Pegasus, Bucephalus, Champion,

Trigger, Seabiscuit, Red Rum.

I'm talking about the stuff

of myth and legend.

Just look at her.

She's absolutely

gorgeous, aren't you?

Equus ferus caballus - the horse, to you and I.

A statuesque pinnacle

of natural art.

This is a creature

supremely shaped to move.

Thanks to 700 mighty muscles...

..and a heart the size of a football...

..the horse is one of the fastest

and most powerful animals on the planet.

They don't call it horsepower for nothing.

So how did the horse

become one of nature's

greatest athletes?

To answer that...

..we must travel back in time...

..to meet the key

movers and shakers...

..before hooves thundered...

..or hearts raced.

Back to a time

when almost nothing at all

moved.

The story of the horse

and, in fact, the story of movement

can be traced, incredibly,

right to our own doorstep.

This is a quintessential

English landscape, a rural idyll of

rolling hills and ancient woodlands.

But I've got to tell you

that I was standing here just over half a billion years ago,

the view would have been very different. In fact, I wouldn't

have been standing, I'd have been submerged deep beneath the waves

on the ocean floor. And over millions of years,

these rocks have been pushed up and laid bare.

And they tell us of the history of that time,

a history written in sand and silt.

A history with some fascinating clues.

Hiding in plain sight

are some of the most precious

fossils on the planet.

But millions of years of weathering have warped these rocks,

making them very hard to spot.

Now, I did tell you they were tricky to see,

but there is one right in front of me here.

Just follow my fingers.

It starts up here,

then it arches down.

You can see the ridges in the rock,

particularly visible here.

And then it comes up towards

my shoulder, and this bit follows

right up past my ear.

These would have been made by fronds

and they would have been attached

around a centre point, which

could have been somewhere here.

This is a fossil of Bradgatia.

And I know it doesn't look like much, it might look like

an old cabbage that's been pressed in the rock to you,

but it wasn't an old cabbage.

It wasn't a plant at all.

And this is a very, very important fossil

because it's a fossil of one of the earliest animals

that ever lived on Earth.

Over half a billion years ago,

this slab of rock...

..was home to some of the very first animals.

Theirs is a peaceful life.

But this strange community

does have a problem.

When animals with large, complex

bodies first evolved,

they couldn't move.

We call them sessile.

Rooted to the ground,

they must rely on the ocean

to bring them what they need...

..and they're powerless

if it doesn't.

Animal life could have remained

stuck in this way forever,

if it wasn't for an evolutionary maverick.

This is a cast of a fossil that's about 565 million years old,

which means it formed around the same time as Bradgatia. Now,

when the scientists first looked at it, they were initially confused.

It's quite difficult to see.

Look, it starts up here and it runs down here.

It's almost as if someone has been running their fingertip

over some soft mud,

and then it terminates down here.

But if you look here,

you can see there are a few little

half-moon shapes. Now, the reason

those scientists were initially confused is they were probably

looking for a fossil of an animal, but this is not that.

What it is is a fossil of something

an animal left behind.

Now, we think the story goes something like this.

In amongst the creatures stuck to the seabed is a tiny animal,

little more than a gelatinous blob.

Like other animals here,

it eats specks of food

that drift on the ocean currents.

But today, the current has shifted...

..and is now carrying the meagre morsels just out of reach.

Deprived of food, the only option

for this stationary population

is to sit and wait for their luck

and the currents to change.

But this animal is a pioneer.

You see, this little blob

can do something

that the other animals can't.

Abandon the safety of its home...

..and move.

With every heave...

..it leaves a mark.

Some of the earliest animal tracks on the planet.

One small step for this tiny blob,

one giant leap for animalkind.

Now, we'll never know exactly when the first step was taken.

We can presume that there were some missteps -

evolutionary stumbles, if you like -

but that leap between being sessile and motile was a profound one.

Today...

..whether they are finding food...

..or mates...

..or shelter...

..our planet is an extravaganza

of motion.

An estimated 97% of animals

moving in weird and wonderful ways.

And none of this would be possible

without one key ingredient.

Muscle.

HORSES WHINNY

To understand just how powerful muscle can be,

we need a demonstration from an expert.

I give you...the leech.

I know, not everyone's favourite animal,

but it won't surprise you to know

that I'm rather a fan of the leech.

What are they?

Well, they're a type of worm,

and there are about 700 species

in the world.

Many, like this one, are parasitic.

This is a medicinal leech,

and it's been used by

medical practitioners

to suck the blood from humans for 3,500 years.

But I digress.

What about its movement?

Well, let's take a look at their body.

First thing you'll notice - no legs.

Its body is made up almost

entirely of muscles.

Muscles are built from tiny cells called myocytes.

We sometimes call them muscle fibres.

Within the leech,

there are thousands,

while an animal like the horse

contains millions

and millions of them.

They work thanks to their superpower -

their ability to contract.

Now, this leech's muscle cells

are arranged in opposing sets.

There are circular muscles

that run around its body

and longitudinal muscles,

which run from one end to the other.

So how exactly does it move? Well,

I'll try and demonstrate that here.

Come on.

It stretches forward

using those circular muscles,

and then contracts its longitudinal muscles

and pulls itself forward...

..so that it can slowly inch across

the palm of my hand

and down my fingers.

Something that I find

quite therapeutic.

You may consider it perverse,

but I'm rather enjoying this.

Today, it's easy to take muscles for granted...

..but half a billion years ago,

it was primitive muscle cells

that turned contraction

into action...

..allowing pioneering animals

to take a leap into the unknown.

And the importance of this

simply can't be underestimated,

because from this point on, movement would become

one of the most powerful driving forces in animal evolution.

To reach the next step in the story of the horse,

we must hit fast-forward.

For the next 40 million years,

evolution gallops on.

THUNDERCLAP

Muscles stretch

and shape animal life,

and more and more time is spent...

..on the go.

As they say, necessity is the mother of invention,

and that was certainly the case for animals experimenting

with early locomotion.

Down here, every trip across

the seafloor demands energy,

and lots of it.

And to get from A to B,

it's thought that ancestors of the horse had evolved to use muscle

in a totally new way. Incredibly,

evidence of this

can still be seen today.

Inside this little plastic tub here,

I have a beautiful animal.

It's called a sea squirt, or a tunicate,

and it's a chordate, which means we're actually related to this.

I know it's difficult to believe, but it's true.

And the benefit of looking at this particular species

is that it's transparent.

I can see inside it.

And I can see a tube running around its body,

and that tube is filled full of

oxygen, minerals and sugar.

It's its blood.

And that tube is contracting.

Waves of muscle contraction are pushing that blood around the body.

Fundamentally,

this is a simple heart.

It's thought that systems like this

allowed this ancestor of the horse

to enjoy an active lifestyle.

Just like the rest of its kind,

nutrient-rich blood

is being pumped through its body,

making its muscles fizz with energy.

Now, most of these creatures

wouldn't win any races,

spending their energy just

wriggling along the seabed.

But the ancestor of the horse

seems to have had an extra boost,

meaning...

..it can swim harder, better,

faster, stronger.

Its remarkable athletic ability

is thanks to an innovative use of muscle

that unlocked the full potential of the heart.

At this point, evolution all starts to go a bit Frankenstein.

You see, for any muscle to contract,

it requires a stimulus, an order,

and that typically comes in the form of a tiny electric zap.

And it's thought that some

muscle cells inside some of

the earliest hearts took charge,

specialised and started to send out

a series of rhythmic zaps.

And all of the surrounding muscle cells complied by contracting,

generating a single powerful pulse.

Now, these mutant zapping cells

are called pacemakers, and almost all animals have them.

We have a single primary pacemaker called the sinoatrial node.

And as soon as those ancient pacemakers began to pulse,

they instigated a revolution.

In the ancestor of the horse,

those specialised pacemaker cells

have now clustered together

in a localised region...

HEARTBEAT

..giving its heart

a more powerful beat.

And over many generations...

..the beat gets stronger.

The muscle walls around the pacemaker thicken...

..chambers form...

..and valves...

..directing blood flow

around the body...

..becoming an iconic,

life-sustaining organ.

It's an ingenious use of muscle,

one that transformed animal locomotion.

When hearts went from being a simple pump to a more complex

muscular mechanism,

it led to a step change in the evolution of movement.

It allowed animals to become bigger, stronger, faster.

It allowed them to get off of that seabed into the world above.

And from that point on,

life would become a slithering,

crawling, walking, running,

jumping and climbing adventure.

Today...

..across the globe,

beating hearts are pumping oxygen

through all sorts of bodies.

Around 2.5 billion heartbeats

will supply your muscles with

the energy they need...

..from your first breath

till your last.

It's a rhythm that connects us all

to the first beats,

over half a billion years ago.

Time to take a leap forward...

..as the descendants of those

early swimmers get bigger,

stronger and faster.

They shapeshift through countless

iterations until

140 million years later...

..they have become...

..fish.

This is an ocean full of powerful bodies.

But here, it's not how many muscles

you've got that counts,

it's how you use them.

Now, there are many forces

shaping evolution.

The need to find food, the need to find mates.

But there are even greater forces at play,

those forces which shape the entire universe.

I'm talking about the laws of physics.

And when it comes to locomotion,

harnessing these would be key.

And fish have achieved that with a remarkable innovation,

something that's startling in its simplicity,

but significant in its importance.

Something that, today,

has helped make fish the success story of our oceans.

Attached to their streamlined bodies,

structures of flesh, cartilage

and bone have evolved.

Tools which their muscles

can control, expanding the mechanics

of movement available to them.

They can be gliders,

thrusters,

rudders.

I'm talking about fins.

And 380 million years ago,

the ancestor of the horse

was a fish, with fins like this.

You can see the fin here.

But look at the base.

It's made up of a series of

robust, strong bones which anchor it to the body,

and they would have been covered with powerful muscles.

And it's this stalk, or lobe,

which gives this group of fishes their name.

We call them the lobe-finned fishes.

Now, I've got to be honest with you, in the open ocean,

this set-up probably didn't confer them with much of

a competitive advantage,

but under certain circumstances,

it proved to be a real bonus.

This is Onychodus...

..an ancient predator

as big as a crocodile...

..with muscular lobed fins.

Now, its size and weight

should be an advantage,

making Onychodus a formidable foe.

But when it swims...

..the water around it is churned up,

giving the game away.

So how does this ocean giant catch its dinner?

The answer lies in those lobed fins.

Inside there is a tool that's just begging to be used,

a tool with enormous potential.

I'm talking about a lever.

You see, the relatively small distance travelled by my hand

and arm here is magnified out there at the tip of the oar,

which is moving far further.

When it comes to generating movement,

muscles are fantastic,

but they do have their limitations.

The lever is life's great multiplier.

Look, a small amount of force

applied by my arms in the boat

is transferred to the tip of those oars,

and it allows me to propel the boat forward.

Not exactly with Olympic prowess, I have to confess,

but with a degree of efficiency.

And it's thought this same principle

helped this hulking fish

to move with incredible delicacy...

..by doing something

very unfish-like.

Using four of its lobed fins,

along with the physics of levers,

Onychodus turns minimum effort

into maximum movement

and propels itself

stealthily across the seafloor.

Swapping swimming for walking,

it saves its energy for one final,

powerful thrust.

Thanks to its four lobed fins,

Onychodus is a master of the ambush.

So, with skills like these,

you'd expect there to be plenty of lobe-finned fish in the sea,

but today, they have almost entirely vanished from our waters.

My goodness!

That was a bit of a workout.

Now, look, levers are very useful in water,

but they could become even more useful somewhere else.

When fish like Onychodus begin

to use their lobed fins to walk,

rather than swim,

they set off a chain reaction.

Over millions of years...

..the thick bridge of bones

inside those four fins lengthen...

..and the muscles surrounding them

shift and alter...

..creating strong, tough appendages.

No longer fins at all...

..but four levered limbs.

This was the birth of the tetrapods.

And today, there are more than

30,000 species,

inhabiting every continent.

A diverse supergroup,

all descendants of those fish

with four lobed fins,

are now putting them to use

in very different ways.

Including the horse.

For many tetrapods today,

moving on land is second nature,

but for their ancestors crawling out of the sea,

it was a very different story.

Moving from one ecosystem

to another which is completely different,

requires a painfully slow process of adaptation.

But the creatures that were making that transition

looked a little bit like this.

Oh, yes.

Look at that.

That's special.

One of nature's jewels.

Absolutely beautiful.

This is a marbled newt.

You see how it got its name, with that marbling running down

its back there.

It's an amphibian.

It spends its spring in ponds going through its breeding cycle

and then at the end of summer, it emerges onto land,

where it spends the rest of the year.

But, of course, it's gone through millions of years of evolution,

which allow it to exploit the best of both worlds -

the wet and the dry.

But what about its movement?

Well, in the ponds, it's a fairly good swimmer, to be fair.

What about on land?

Let's give it a go.

They're tentative, they're slow,

they're laborious, they're calculated.

Their little bodies bending from side to side,

as they rather lethargically

move through the environment.

I've never seen a newt galloping or frolicking.

I'm never going to. But this does

tell us something very important.

Movement on land is hard.

Very hard.

This newt can get away with having

four left feet because in a pinch,

it can retreat to a habitat

it finds easier to negotiate.

But 350 million years ago,

if the ancestors of the horse

were to pursue a life

solely on solid ground,

they would need to be far more coordinated.

And the answer to their coordination conundrum came, once again,

with an evolutionary innovation

from the ever-adaptable muscle.

Inside almost every muscle in my body,

I have something called a stretch sensor.

And stretch sensors are highly specialised muscle fibres

that are constantly monitoring how and when

those muscles are moving.

The key thing is that they are all linked together in a complex web,

so each individual muscle knows

exactly when every...other muscle

is moving. Now, despite the fact that this is an incredibly

complicated system, I bet that you've never even thought about it,

and that's because you don't have to,

despite the fact that it's crucial

for every single move that we make.

Tiny stretch sensors allow the muscles to communicate

with the central nervous system,

giving us and most living tetrapods

the ability to co-ordinate movement

with astonishing precision.

Often, faster than you can think.

Look at that.

Just look at the legs there.

Every part of them is moving independently,

in isolation, at the same time.

And then the weight -

that's got to be balanced between all four feet.

And running down those legs -

just going to speed it up, look at that -

are ripples of muscles.

That's the glutes, that's the quads,

that's the hamstrings, all working in unison.

Without these little gizmos,

these stretch sensors hiding in muscles

and the complex network that joins them all together,

animals with bodies like this simply would not have been able to evolve.

It was down to this innovation

that animal bodies could become

radically more coordinated,

and those tiny little bones, once hidden in those fish's fins,

could really come into their own.

Those fully terrestrial animals

could put one foot in front of the other with extreme precision...

..and this was a game-changer.

Time for us to motor on.

Over the next 300 million years,

the tetrapods scattered across the Earth.

Whilst life faced some cosmic curveballs...

..it was never fully derailed.

And evolution carried on...

..tumbling us...

..into a new world...

..where the way you move...

..can be a matter of life

and death.

This is Phenacodus.

Life looks pretty serene,

but Phenacodus must constantly

be on guard, because this world

is full of expert movers...

BRANCH SNAPS

..whose bodies...

..have evolved for the chase.

GROWLING When the hunt is on...

..surging adrenaline, thumping hearts

and straining muscles will only take you so far.

Faced with a situation it can't

muscle its way out of...

..the secret to Phenacodus's

survival lies in its feet.

Come on, Siddy! Nance, come on!

DOG BARKS

Do you know, sometimes, people say, "Why poodles?

"Why poodles?" they say. And I facetiously reply,

"Are there other breeds of dog?"

I mean, look at them.

Boundless energy, incredibly loyal,

and they can also help us

with an important part of our story.

You see, hidden beneath

this curly fur here is a crucial

step change in evolution.

Now, I don't need to tell you about my foot and leg,

you've got your own. Starts off at the toe,

goes across the foot to the ankle,

then you've got the shin, the knee, the thigh.

We put our feet down

onto the ground, we plant them

flat on the ground like that.

We're what we call

plantigrade animals. It's quite an efficient way of walking.

Nancy, on the other hand, is altogether different.

Let's take a look at her back leg here.

You see, her toes stretch

from here to here.

The rest of her foot bones

all the way up to here, which looks

like a backward-pointing knee,

but this is, in fact, her ankle.

Her knee is all the way

up here. So Nancy

is effectively standing up

on her toe bones.

She's a digitigrade animal,

and that's altogether different.

It means that you move in a very different way, doesn't it?

Shall we show them?

Come on, let's go. Come on.

Right, Sid, Nancy.

Let's see them in action.

BARKING

Woo-hoo-hoo! BARKING

Look at them go! You see,

this change in anatomy allows the leg to become longer,

the stride to become longer,

and more efficient use of all of that elastic energy

stored in the muscles and tendons

above their ankle.

Look at that!

Bouncing about.

BARKING

Alacrity, agility.

Critically, speed.

That is a happy poodle.

And, you know, this adaptation has occurred a number of times

in terrestrial animals. But having said that,

if you really want to be a creature living life in the fast lane,

evolution can offer you one more gear.

Siddy, Nance, come on! Come on!

When it comes to speed and efficiency, plantigrade -

that's us - will get you from A to B.

Digitigrade - like my dogs -

ups the revs.

But 56 million years ago,

Phenacodus was on the verge of something new.

Not just bouncing on the balls of its feet,

but pushing off from the very tips of its toes...

..lengthening its stride even further.

So future generations take the concept...

..and run with it.

As bones elongate

and muscles bulk up...

..they spend more

and more time on tiptoe...

..and in the process...

..find the most efficiency

in trading many toes

for one large,

powerful shock absorber.

Look at this.

This is clearly a cast

of a fossil of a hoof.

A hoof at the end of a very long leg.

A leg that's clearly all about movement.

A leg, though, that is surprisingly different than ours.

You see, essentially, it's foot

all the way from here to here.

This is the equivalent of our ankle.

The bone here would be like those in the sole of our foot.

And down here,

it's balancing on a single tiptoe.

The hoof itself would have been made of keratin,

just like our fingernail.

And also, what's interesting is at the other end,

the front legs weren't attached to the skeleton.

They were embedded

in a heavy mass of powerful muscle,

and this gave it the capacity for a greater stride.

You see this groove here?

Running down here would have been a tendon,

perhaps half a metre long,

a giant elastic band.

But it is a leg with compromises.

I mean, you can't pick anything up with a hoof,

you can't manipulate anything.

It's lost all dexterity,

at the expense of speed.

This three-million-year-old hoof

tells us of the arrival

of a new group of animals.

Animals we call Equus.

These single-hoofed mammals

first evolved on the plains of North America...

..before spreading across the globe.

Among them

was one remarkable species.

Equus ferus.

Known to you and I as the horse.

Its body shaped

generation after generation...

..by the evolutionary drive to move.

700 muscles, passed down

over half a billion years,

from a pioneer who changed the world.

A huge heart, with an ancient beat,

that began deep beneath the waves.

Long levered limbs

that once helped a fish to walk...

..and four large hooves,

the legacy of ancestors

who had to run for their lives.

But there's one final twist

in the story of the horse,

because Equus ferus

was about to encounter

a new force of evolution.

Another species

on an evolutionary journey of its own.

A bipedal tetrapod,

with opposable thumbs,

and an overinflated sense of self-worth.

4,000 years ago, Homo sapiens -

that's us - inhabited

much of the planet.

HORSE WHINNIES

We had city states and agriculture.

Empires were beginning to grow.

And at this time, in Europe and Asia,

we begin to see evidence

of a growing relationship

between horses

and humans.

Now, no-one is exactly sure how the first horse was tamed.

Maybe someone caught one of those wild horses,

took it into captivity, gave it shelter, food,

cared for it, loved it and trained it.

But what we do know is that in pretty short time,

we took these strong, efficient, powerful animals

and turned them into our perfect companions.

And, you know, we didn't just tame them.

Over generation after generation, we bred them,

choosing those characteristics which favoured the way

we wanted horses to be.

So in the end, we took the wild horse

and we turned it into the workhorse.

We chose the strongest.

We chose the most powerful.

But we also chose the friendliest,

the most amenable.

And for better or for worse,

over the generations,

the horse was altered.

The ancestors of the modern horse

were a pretty wild bunch.

Diverse not only in terms of their physical appearance,

but also, their genetic make-up.

And about 4,000 years ago,

we see two gene variants appear.

HORSE WHINNIES

Now, one of those appears to make them less aggressive,

more manageable.

And the other, which appears to give them a stronger back,

making them easier to ride.

Now, what's interesting is that

within the space of just a few hundred years,

we'd spread those gene variants

throughout the population.

The wild horse was effectively gone.

We had one global species,

selected by humans.

You.

Yes. I know.

It wasn't my fault.

I wasn't around then.

Today, the horse goes by a new name.

Equus ferus caballus.

The domestic horse.

Our relationship is a special one.

Together, we've travelled to

every corner of the globe.

Step by step...

..and side by side.

We often think of evolution

as a battle between species,

a game of winners and losers,

a game of survival of the fittest.

But very occasionally, species come together

and the result is greater than the sum of their parts.

Now, there's no doubt we played a hugely instrumental role

in the evolution of the horse,

but then the horse has had an impact on us too,

because without this remarkable animal as our greatest partner,

we simply wouldn't be the species we are today.

The horse's evolutionary journey

is just one thread

in an extraordinary tapestry...

..that weaves together every animal,

in fact, every living thing

on our planet.

It's taken four billion years

to get here, but, boy,

has life come a very, very long way!

From the cell that began it all...

..to sex...

..to competition...

..to predation and protection.

From the oceans to the land

and, for some, back again.

For others, onwards to the skies.

There was a bum that changed the world.

There were jaws, limbs,

hearts and minds.

Minds which have evolved to sense,

to move, to love,

to contemplate...

..and, in our case,

to begin to understand

our own origins.

A journey of knowledge

that we're still on today.

There's an outdated view,

a mistaken idea,

that we humans are the be-all and end-all of evolution.

That everything we've explored, everything we've shown you

in this series was just about making us the perfect organism,

the paragon of life on Earth.

But it's simply not true.

We're not perfect and we weren't made.

We've been shaped by exactly the same forces

that have shaped every organism that's ever lived on this planet.

And through a startling twist of fate,

we are now having a profound effect

on evolution ourselves.

A dramatic, rapid and scary one

because of what we're doing to our environment

and because we're driving a massive extinction event.

Now, evolution does feast on extinction.

It loves the opportunities, the vacancies.

So whatever we do now, life will go on.

Life will be bright, life will be beautiful,

life will be wonderful.

But in evolutionary terms, what about us?

Could we become shorter,

slower, more short-sighted?

Might we become smarter, more stupid?

I don't think it really matters about our anatomy at this point.

I think what matters is how we think,

imagine and create our way out of our situation.

I think that what needs to be driving human evolution right now...

..is hope.

But before we go...

..how did we bring the story

of evolution to life?

The way that one animal,

over millions of years,

can transform into something radically different

was once a mystery lost to time.

- If we think about a book, we have lots of different pages

that tell us the story from start to finish.

However, with evolution and fossils, some of those pages are missing.

- But occasionally, evidence

is unearthed of the process

in action. In 2004, palaeontologists

in the Canadian Arctic

discovered a ground-breaking fossil.

- So this is a cast of Tiktaalik.

Now, Tiktaalik lived about 375 million years ago,

and it's got the scales very much

like modern-day fish have today.

And what's quite unusual is that it actually has a neck.

And these bones that are around there,

these are the sort of collar bone

or shoulder girdle. It looks like

a cross between a fish and an amphibian,

and that's because that's exactly what it is.

- Tiktaalik was really this kind of

unique snapshot in evolutionary time

at this key moment

for the water-to-land transition.

- So it's a perfect example of

a transitional fossil.

- Transitional fossils are incredibly rare.

They play the really important role of filling those gaps

between morphologies that we kind of know are there,

but we don't really know exactly

what they might have looked like.

- Transitional fossils represent

just one out of millions,

possibly billions, of individuals

that, over generations,

contribute to evolutionary change.

Coming up with a way to illustrate this

posed a huge challenge

to the visual effects team behind the series.

- Evolution does not move in a straight line,

because it is purely opportunistic

and slightly haphazard.

- It's tinkering. It's messing with what's already there,

rather than kind of always

necessarily inventing something from scratch.

- It's all about a great grand experiment

and just seeing what happens.

- The team spent thousands of hours

crafting and animating

computer-generated models

to bring ancient animals

back to life.

But to illustrate the randomness

and variation seen as life evolves,

they needed to experiment.

After consulting scientists to accurately model

the key evolutionary changes,

they used generative AI software

to create hundreds of variations,

representing countless generations.

And by hand-selecting and merging

the best results with their original

animations, they were able

to condense millions of years

of evolution...

- Look at that! - There's bones inside!

- No way!

- ..into a matter of seconds.

- In reality, this would take

millions of years.

- This is a fantastic way

to illustrate the evolution of form.

This is basically how I imagine it playing out in my head.

- This series has been over

four billion years in the making...

..and as a certain Charles Darwin

once wrote,

"From so simple a beginning

"endless forms most beautiful

"and most wonderful have been,

"and are being evolved."

- One of the big key life lessons that

I've learned from studying evolution

is that change is constant

and change is the norm. So things

have always changed and will always

continue to change, and life

will always continue to adapt.

- That's how it's always been,

and there's no reason to believe

that's not how it's going to continue to be.

- Do you want to know how an elephant is related to a clownfish?

Discover more in a poster from the Open University on

the tree of life. To get your free copy,

scan the QR code on-screen or ring...

..or visit...