All language subtitles for BBC - 01 - Life Story.eng

There is one thing that everyone
on Earth has in common.

We all live, eat and breathe
within the human body.

For two years, I have been exploring
this unique dwelling place.

I want to show you what I have seen.

To come with me,
you'll have to cross the globe,

from Australia,

through Africa,

to America.

You'll have to journey into space,

and into a place as mysterious
but much closer to home.

We've developed new techniques
to help you get there.

New cameras to show you the way.

And we'll look at familiar things
with a fresh eye.

You'll journey with me
on the road that your body takes.

Through dangers.

Through miracles.

And through time.

We'll see the human body
in all its forms,

fom our beginning

to all our ends.

I'm a doctor and a scientist.

I've spent my working life
looking at the human body.

Now I'm going to see it
in a new light.

Come with me.

This is Charlotte.

She was born just a few hours ago.

Like most of us at birth,
there's really nothing to her.

A bit of fat, a little sugar.

A bit of protein.

She's really just a collection of chemicals.

And yet she's the most
complicated thing on Earth.

During her lifetime,
she'll achieve the most amazing things.

She'll eat for nearly three and a half years,

consuming 7,300 eggs

and 160 kg of chocolate.

She'll produce 40,000 litres of urine
and spend over six months on the loo.

She'll dribble 145 litres of saliva
before her first birthday.

She'll crawl 150 km before she's two.

Then she'll learn a new word
every two hours for the next 10 years.

By the time she's ten, her heart
will have beaten 368 million times.

She'll spend
a little over 12 years watching TV.

And two and a half years on the telephone.

She'll spend two weeks kissing.

She'll grow 28 metres of fingernails,

and 950 km of hair on her head...

and more than two metres up her nose.

By the age of twenty one,

she'll have breathed
over 31/2 million balloons of air.

She'll work for a total
of just over eight years.

She'll produce 200 billion
new red blood cells each and every day.

She'll be able to put a name to 2,000 people.

150 of them she'll call her friends.

She'll shed 19 kg of dead skin.

She'll have sex 2,580 times..

with five different people.

She'll fall in love twice.

She'll blink 415 million times.

Her eyes will be able
to distinguish over a million colours.

If she gets married,
she'll spend �6,809 on her wedding day.

to the same person for the rest of her life.

She'll have two children

and four grandchildren.

When they grow up,
only two of her eight great-grandchildren

will remember what her name was.

In Britain, she's likely to live for 79 years;

in France, 82 years; in the USA, 80 years;

and in Africa, only 55 years.

By that time,
she'll have walked over 22,000 km

and talked for 12 years.

It's an amazing list.

In fact, no life is an ordinary story.

We will each in our time
do an incredible amount.

And the driving force behind everything we do

is the most complicated and mysterious
organ in our bodies - it's our brain.

This is something
I've never done before in my life,

and I never thought I would.

Despite my brief experience,
I can do a bit of it on auto-pilot.

A little bit anyway!

(INSTRUCT0R) Braking. Braking.

Braking... No, no!

You were going too fast.

This kind of driving
takes a whole new range of skills.

And you need to be able
to use them almost automatically.

It's my brain that lets me do that.

My brain is now doing
half a dozen tricky new jobs all at once,

without my even thinking about it.

So much so that I can devote
some of my attention speaking to you.

(INSTRUCT0R) Lift off.
Get your brain into gear!

And that's what brains are so good at.

They manage things
without us being conscious of them.

Your brains are doing it right now,

because whilst I've been doing
six new things,

your brains have been doing
tens of millions of tasks,

just while you're watching television.

Put another way,
it's as if you're not just driving this car,

but driving every car,
bus, bike, taxi, lorry in the country

at the same time.

And you just thought
you were putting your feet up!

To see how busy your brain really is,

you have to look at the world differently.

Everything that's alive, and some
things that aren't, gives off heat.

That's what you're looking at now.

All your body
is burning up energy and creating heat

as it goes about the business of being you.

But the hottest bit of you is up here.

Your brain burns up
the most energy in your body,

almost a fifth of all the calories you consume.

And it uses up almost the same amount

whether you're concentrating
on something difficult

or just wondering whether to put the cat out.

Your brain is constantly challenged
with its most difficult task:

keeping you alive.

Right now,
there are a few things on your mind.

Tonight's dinner, for example.

For starters,

your brain is coordinating
a major haulage operation.

Though the route is usually downhill,
food doesn't fall to your stomach.

When you swallow,
your brain triggers muscle contractions.

They squeeze things along
in your oesophagus at 4 cm per second.

The first scheduled stop is the stomach.

It's essentially a biological liquidiser.

Its lining is covered in delicate folds

which allow it to expand with each mouthful.

Inside, a mixture
of enzymes and hydrochloric acid

start to digest your food.

Your dinner's probably still inside.
It churns away for about four hours.

Soon it will be released
into your small intestine,

and, at a cue from your brain,
bile will be added.

This will help you break down fats.

You'll be carrying tonight's dinner
for about 24 hours.

So I hope you liked it.

When it does leave you,

it will take about 25 grammes
of dead cells from your gut with it.

But don't worry.

You're constantly
replacing cells from head to toe.

Your brain is managing the body's
workforce of 50,000 billion cells.

And most of them
don't last more than a few years.

Cells are constantly dying...

and being replaced by new ones,

up to a billion new cells for old every hour.

This means that most of your body
is a good deal younger than you are!

But these cells aren't replaced
and they're particularly special.

Each one has a natural tendency to twitch.

They're heart cells, and millions
working at once is a heartbeat.

It's your head that rules your heart,

as it's your brain that decides
what rate your heart should beat at.

The part of the brain controlling your heart

is looking after the outside of you, too.

Your body must maintain
a temperature of 37 degrees Centigrade.

And your brain has a range
of tricks up its sleeve to do it.

This is skin magnified a thousand times.

If you look closely,
it's covered in holes.

They're the openings of tiny ducts,

tubes through which sweat can flow.

There are about 65,000 of them
on the palm of your hand alone.

If you're getting too hot,
your brain switches on your sweat glands.

As the sweat evaporates,
it will help cool you down.

Should your brain decide
that warmth is needed, it has another plan.

Goose pimples.

They trap warm air
near to the skin and so keep vital heat in.

So, all that is being controlled
from here, inside your head.

And don't think you'll get out
of all the hard work by nodding off.

Even when we're relaxed or asleep,

our brains don't let up.

This contraption is covered in electrodes,

picking up part of my own brain's activity.

128 sensors detect tiny signals
emitted as my brain cells fire.

This is the pattern produced when I am relaxed.

Even without a thought in my head,
my brainwaves show I'm busy.

The truth is our bodies are always busy.

They just don't tell us about it.

What we see
as the monotony of our daily lives,

when it seems that nothing happens,

is actually the result
of much activity inside our bodies.

We're performing thousands of tasks
every second of every day.

Simply being is part
of a complicated balancing act,

the mechanics of which
are completely hidden from us.

Just as our bodies hide
the miracle of everyday life,

so they hide from us
an even bigger surprise.

It's the story of how
we came to be the way we are.

And it is an amazing story.

It will change how you think about your body.

The way we live, the shape we are,
even the way we think,

was decided for us thousands,
millions, even billions of years ago,

when the human body didn't even exist
and planet Earth was unrecognisable.

Here we are, 8,000 feet above sea level

in America's Yellowstone National Park.

If you'd been on the planet
3 billion years ago,

it would have looked something like this.

The Earth was covered in volcanoes,
billowing steam and sulphurous water.

Had you been standing here,

you'd have been present
as the story of life was unfolding.

Had you been standing here,

you'd have been standing
by the planet's most advanced life form.

In this almost boiling water

there are thousands of long, thin strands.

They are colonies of tiny,
heat-loving creatures: bacteria.

0nce, long ago, this was
the most complex life form on Earth.

What's surprising is it's still here today,

just like 3 billion years ago.

Whilst dinosaurs came and went,
and many other species died out,

this has survived practically unchanged.

This is because
their environment has stayed the same.

The water comes from deep in the Earth

and so is always the same temperature.

Just metres away,
the environment is very different.

Away from the thermal vents,
the temperature fluctuates.

Billions of years ago,
bacteria were living here, too.

But as the conditions changed,
they changed as well.

From one generation to the next,
there were alterations.

They were almost insignificant,

but these tiny changes
started an amazing process.

Because if you add up enough
tiny changes through generations,

you get a revolutionary transformation.

From being simple bacteria,
they became more complicated.

Single cells became groups of cells

and then early plants and animals.

And the changes continued.

Dozens of species became hundreds,
hundreds into tens of thousands.

Parts of bodies were adapted
to meet new challenges.

Great leaps were made.

A fish's fins, over countless
generations, developed into legs,

and it became a reptile.

Some reptiles developed feathers
and became birds.

0thers became mammals in every shape
and size from blue whale to baboon,

every creature we see on the Earth today,
including ourselves.

All this happened.
It's the miracle of evolution.

The human body is just one branch
in the huge, spreading tree of life

that grew from those simple bacteria.

Yet we carry with us the remnants
of what has gone before us in our strange past.

And there is a place we can go
to see just one of those remnants,

shaped by one of evolution's
truly incredible transformations.

It's inside my own head.

All we need to do is go and find it.

This is my ear drum, a thin skin
stretched tight across my ear canal.

But what I want to show you
lies on the other side of my ear drum.

This device can take me there.

I'm inside a huge magnet with a field strong
enough to lift a car clean off the ground.

It's a Magnetic Resonance Scanner

It can reveal layer by layer
what's inside my head.

Up until now this has been
the forefront of medical imaging.

But we're about to take it one step further.

By putting the medical scans together,
we've created a 3-D picture of my own head,

and I can look at any part of it I want to.

I can see the muscles that make up my face.

My skull.

And my own brain.

So now I can take you
on that journey into my ear

in a way that's never been possible before.

This time we can fly
straight through my ear drum.

We're inside my head and at last
I can show you what we've come here to see.

0n the right it's my ear drum again.

But now we're looking at it from the back.

Attached to the middle of it
is what I want to show you.

It's a bone.

Though it's towering above us,
it's actually tiny,

about the size of a grain of rice.

It's the first in a chain of three bones

which transfer the vibrations of my ear drum

to receptors in my cochlea.

They are the smallest bones in my body

and they're perfectly engineered
to perform their task.

Yet these bones will reveal
how evolution has transformed us,

because they were once something
completely different.

Let me take you back, even before birth,

and the bones will tell us their story.

A foetus in the womb, just twelve weeks old,

and it's only a few centimetres long.

It would fit in an eggcup.

Deep inside its head,
its ear bones are forming.

Now let's look
at younger and younger foetuses.

Eight weeks.

Seven weeks.

Six weeks.

We are actually witnessing something amazing,

because at certain times
in this early development,

our human embryo
portrays the shapes of the embryos

of some of our distant
pre-human ancestors.

In other words, what we're looking at now
is like the embryo of a creature

which we evolved from
millions of years ago.

It's just as if we are journeying
back in time,

virtually rewinding evolution
to show episodes in the history of life.

If we use the magnetic scanner,

incredible detail is revealed.

We can see right through the skin at the brain
and the spinal chord beginning to form.

And the beginnings of an eye
behind the emerging hand.

Like some of the creatures
that preceded us on the evolutionary tree,

it has a curved spine

and what might be a tail.

And those amazing ear bones we saw earlier
are taking shape on the outside of the head.

The cells that will make them
are located here -

tiny grooves almost hidden behind that hand.

Millions of years ago,

the embryo of a distant ancestor of ours would
have shared with us many of these features.

As well as giving rise to us,

it gave rise to all sorts of other creatures.

In those creatures,

these features that we're looking at here
have evolved quite differently.

We can actually see it happening
with the ear bones,

because those very same grooves
that in us will become our ear bones

in this creature become something else entirely.

This is the embryo of a fish.

Here is its heart
and it, too, has a curved spine.

And the tiny grooves here,
just a fraction of a millimetre long,

have evolved to become not ear bones
but supports for its gills.

So, some time long, long ago,

this lot and I shared a common ancestor.

And like them, it, too, had little bones
around its gills which helped it to breathe.

But as we evolved,

these little bones were adapted
for an entirely different job:

to become the intricate mechanism
of our ears.

And our ear bones are not the only things
to have been transformed in this way.

Such apparent miracles
are in fact all around us.

The rest of our ears, that allow us to balance
and walk upright as well as hear,

our limbs and hands, our whole body
has been shaped by the process of evolution.

Everything about the human body
has been inherited and adapted

from something
our ancestors had a long time ago,

though they may have used it
for something different.

We are recycled from the past.

0nce we begin to understand
the source from which our bodies are derived,

the way we look at ourselves
can never be quite the same again.

So every part of the human body
bears a shadow from our distant past.

Evolution has adapted our bodies
from those of our ancestors,

all the way back since life was as simple as that
in the steaming pools of 3 billion years ago.

It is incredible,
and it's incredibly hard to believe, too,

because although we've changed so much,

we don't actually see
any of those changes happening.

Generation after generation,
we just look the same.

The problem is one of time.

The periods over which
even tiny changes happen are so long

they're almost beyond our imagination.

But to make sense of those time periods
and to see them in perspective,

I've brought you here,
to a cave deep in the French Pyrenees.

In the middle of the last century,

a bookseller from the nearby town
of Toulouse used to visit this cave,

and as a hobby he dug around for bones
and evidence of prehistoric remains.

And he did this for some forty years.

And then, late in the afternoon,
on June 11th, 1905,

having been digging all day, he prepared to go
but chose to go by a different route.

As he left, he was passing this wall
and something caught his eye.

He lifted up his lamp
and this is what he saw.

Stencils of human hands
from merely 30,000 years ago.

They are amongst the oldest images
made by human beings on the planet.

They are six times older
than the pyramids in Egypt

and eight times older than Stonehenge.

Quite what they signified to the people
who made them, no one knows.

They were a Stone Age people,

and they came here
at the coldest part of the last Ice Age.

And over here
are the most interesting images of all.

It is thought that these stencils here
were made by someone no bigger than a toddler:

a child in a primitive world,

the son or daughter of somebody
who we would think of as a caveman.

And yet if I had taken such a child
and brought it up as a baby in my own house,

it would be indistinguishable
from my own children.

Because by the time these people
pressed their hands against these walls,

all the changes which make us what we are
had already happened.

The evolution of the human body was,
to all intents and purposes, complete.

If this child were to be raised
with my own children,

it would look the same,
it would talk the same,

it would play the same computer games,

and it would grow up wanting to be a doctor,

a footballer or maybe even an astronaut.

What amazes me more is that,

although we've changed so little
in so many thousands of years,

each of us changes so much
in just one lifetime.

We tend to think of growing up
as just getting older and bigger.

But as we make our way through life,

our bodies change much more significantly
than we realise.

In fact, we change
just as dramatically as a caterpillar.

A caterpillar is an eating machine

and that's just what it needs to be,
to stockpile the energy it will need to reproduce.

Yet, to meet a suitable mate,
it may have to travel many miles

and it's hardly equipped for that!

But evolution has provided
the caterpillar with a solution.

0ne creature is recycled into another.

A new challenge has been met
with a new answer.

0ur bodies, too, face different challenges in life
and we are reworked to cope with each of them.

From the moment we are born,
we are changing...

and adapting to life's demands.

And every change we make
follows a plan drawn up for us

by the millions of generations
that have gone before.

In this series, I'm going to show you
the science of these changes throughout life.

How our brain cells are wired up
when we are children.

How hormones transform us at puberty.

What changes happen inside our bodies.

How our muscles become stronger.

How our brains mature as adults.

And how our bodies continue to alter
throughout our lives.

But if I were to tell you
just the science of these changes,

I'd be missing
the most important thing of all.

Let me show you what I mean.

This is the amount of tears
that an average person cries during a lifetime.

Just a fraction under sixty-five litres.

0r, to put it another way,

about one million,
eight hundred and fifty thousand drops.

So what do we know about them?

Well, each tear
weighs 35 thousandths of a gramme

and is about as salty
as this part of the River Thames at Greenwich.

Tears are produced by a gland above the eye
which is literally squeezed when we cry,

and the tears come down six tiny tubes
about the thinness of a human hair.

As far as we can tell,
of all the animals in the world

only humans actually cry
when we're hurt or upset.

About twenty-eight drops each time.

including sugar and antiseptics.

But what's the most important thing to know
if all these were your tears?

0f course, it's why you cried them.

How many of these thousands of droplets
were shed in fits of anger?

How many in pain?

How many in love? In grief?

How many in sorrow?
How many were shed by a baby?

And how many by an old man
facing the end of life?

The truth is a knowledge of the science of life
is only made complete

by a knowledge of those living it.

The human body
is not just a biological machine,

it's much more than that - it's a person.

In this series, it's people that will tell us
what the body's ever-changing story means.

Take Zak, for example. Having already
mastered the complexities of crawling,

he'll be taking his first steps.

When it comes to growing up, 12-year-old
Beatrice will ride the rollercoaster of puberty.

(BEATRICE) When you're a teenager,
apparently you go bolshie.

You get your periods, you get pubic hair,

you get taller, you get...sort of...
wider at the hips, I think. I can't remember.

(BEATRICE) It's painful to run,
I can tell you that,

because what happens up above, you have to
start wearing a bra. Sorry, had to mention it!

It gets really painful to run.

Month by month, Jeff and Phillippa will share
with us perhaps the body's greatest miracle.

(PHILLIPPA) I marvel at the fact that
this is going on with no intervention from me.

It's just my body taking over
and doing it all.

And I'm not in control of it at all really.

It just all happens.

In adulthood, we reach
the peak of human achievement.

Marcia, an astronaut, has scaled the heights.

(MARCIA) There is nothing in our experience,

genetic, metaphysical, emotional,

psychological experience, that prepares us
for being off the planet.

(MARCIA) You can look
at all of the pictures from space,

and there is something about looking out
the window that is not describable.

And we'll be living through the ravages of ageing
with 76-year-old Bud and his wife Viola.

They live and work on a farm
in the mid-west of America.

What I remember about Bud,
he had the prettiest, waviest hair.

- That's different now.
- Yes, it is!

And his skin was smooth, no wrinkles.

And he didn't have a little pot here.

And in our last chapter,
as his body slowly succumbs to cancer,

Herbie will take us on his final journey.

(HERBIE) I know I'll never see this film
in my lifetime.

I like this because everybody sees that
a human can manage an illness like mine.

Everybody can see in this film

there is a way to make the best
from the end of your life.

So this is the story of the human body,

a tale of fantastic changes
and amazing achievements,

written over millions of years of evolution

and told afresh
by each of us during our lifetime.

It surely is the greatest story ever told.

And every one of us has a part in it.

From new-born baby upwards,

this line follows the journey
we will all make through life.

Each person is one year older than the last.

All of us have a place
somewhere along this line,

looking forward, looking back,

or perhaps a bit of both.

Seen like this, stripped of the trappings
of wealth and status,

we have one thing in common,

the one place we all inhabit,
the one vehicle we all travel in:

it's the human body.

Seeing your body
in ways you've never seen before,

perhaps you'll share my sense of wonder
at how it shapes us all into who we are.