All language subtitles for Wonders of Life 1of5 What Is Life_Subtitles01.ENG

PROFESSOR BRIAN COX: 7fhis creature
is a wonder of life.

A voracious predator,

this male has lived under water
for nearly five months,

feeding, growing,

preparing for this moment.

He is about to undertake one of
the most remarkable transformations

in the natural world.

From ağuatic predator

to master of the air.

(BUZZING)

The brief adult life of a dragonfly

is amongst the most energetic in nature.

Dragonflies are
the most remarkable animals.

You can see their

incredible agility

in flight just watching them skim
across the surface of this pond.

They can pull two and a half G in a turn

and they can fly at 15 miles an hour
which is fast for something that big.

They've been around on Farth
since before the time of the dinosaurs.

And in that time they have been
fine-tuned by natural selection

to do what they do,

which is to catch their prey
on the wing.

So, dragonflies are beautiful pieces
of engineering.

They're intricate, complex machines.

But is that all they are?

Because once their brief lives
are over, their vitality will be goöne.

And this raises deep guestions.

What is it that makes something alive?

And how did life begin
in the first place?

So, what is the difference
between the living and the dead?

What is life?

(MYSTICAL MUSIC PLAYING)

I've come to one of the most
isolated regions of the Philippines,

to visit the remote hilltop town
of Sagada.

İt's a two-day drive
from the capital Manila,

over some of
the country's roughest roads

that wind their way
1,500 metres up into the hills.

This is a place
where the traditional belief

is that mountain spirits give us life

and that our souls return
to the mountain when we dlle.

And where the people who live here
still imagine

that the spirits of the dead
Walk among the living.

(OVERLAPPING CHATTER)

(CHILD LAUGHING)

Tonight is November the first

and here in Sagada,
in fact, across the Philippines,

that means that it's
the Day of the Dead.

That's a day when people come
to this graveyard on a hillside

and, well, celebrate the lives
of their relatives.

The people light fires to honour
and warm the departed,

inviting their souls
to commune with them.

No matter how
unscientific it sounds, this...

this idea that there's some
kind of soul or spirit or...

animating force that makes

us what we are, and that persists
after our death, is common.

Virtually every culture, every religion,

has that deeply-held belief.

And there is a reason for that.
Because it feels right.

I mean, just think aboutit.

İt's hard to accept that when you die,
you will just stop existing.

And that you are, your life,
the essence of you,

is just really something that emerges
from an inanimate bag of stuff.

(SPEAKING TAGALOG)

Don't get too close. Hooray!

You can see that these people feel

not only that they can celebrate
the lives of their relatives,

but they're coming, in some sense,
to communicate with their relatives,

even though
their physical bodies have died,

they are still, in some sense, here.

And when you think about it,
that's not so easy to dismiss.

I mean, if we are to state
that science can explain everything

about us, then it's incumbent
on science to answer the guestion -

what is it that animates living things?

What is the difference
between, er...

a piece of rock that's carved
into a gravestone and me?

From millennia, some form
of spirituality has been evoked

to explain what it means to be alive

and how life began.

İt's only recently that science
has begun to answer

these deepest of guestions.

In February, 1943,

the physicist Erwin Schrodinger
gave a series of lectures in Dublin.

Now, Schrodinger is almost certainly

most famous for being one of
the founders of guantum theory,

but, in these lectures,
which he wrote up in this little book,

he asked a very different guestion.

"What is life?"

And right up front on page one,

he says precisely what it isn't.

"It isn't something mystical,"
says Schrodinger.

There isn't some mağgical spark
that animates life.

Life is a process.

It is the interaction between matter
and energy described

by the laws of physics and chemistıy.

The same laws that describe
the falling of the rain

or the shining of the stars.

So, the guestion İs,

how is it that this magnificent
complexity that we call life

could have assembled itself
on the surface of the planet

which itself formed

from nothing more than
a collapsing cloud of gas and dust?

To Schrodinger, the answer had
to lie in the way living things process

öne of the universe's
most elusive properties.

Energy.

Energy is a concept
that's central to physics

but, because it's a word
that we use every day,

its meaning has got a bit woolly.

I mean, it's easy to say whatit is,
in a sense.

I mean, obviously this river
has got energy

because,
over the decades and centuries,

it's cut this valley
through solid rock.

But while this description
sounds simple,

in reality
things are a little more complicated.

For me, the best definition is that

it's the length of a space-time
core vector in the time direction.

But that's not very enlightening,
I'll grant you that.

Över the years, the nature of energy

has proved notoriously difficult
to pin down.

Not least because it has
the seemingly magğical property

that it never runs out.

It only ever changes
from one form to another.

So, take the water in that waterfall.
At the top of the waterfall,

it's got something called
gravitational potential energy,

which is the energy it possesses due to
its height above the EFarth's surface.

See, ifl...

scoop some water out of the river
into this beaker,

then I'd have to do work to carry it up
to the top of the waterfall.

I'd have to expend energy
to get it up there.

So, it would have that energy
as gravitational potential.

I can even do the sums for you.

Half a litre of water
has a mass of half a kilogram

multiplied by the height.
So, that's about five metres

and acceleration due to gravity
is about 10 metres per second sguared.

So, that's half times five times
10 is, uh, 25 joules.

So, I'd have to put in 25 joules

to carry this water
to the top of the waterfall.

Then, if I emptied it

over the top of the waterfall, then all
that gravitational potential energy

will be transformed into
other types of energy.

İt's sound,
which is pressure waves in the air.

There's the energy
of the waves in the river

and there's heat.

So, it will be a bit hotter down there

because the water İs cascading into
the pool at the foot of the waterfall.

But the key thing is

energy is conserved.
İt's not created or destroyed.

So, because energy is conserved

if I were to add up
all the energy in the water waves,

all the energy in the sound waves,

all the heat energy
at the bottom of the pool,

then I would find
that it would be precisely egual

to the gravitational potential energy
at the top of the falls.

What's true for the waterfali

is true for everything in the universe.

It's a fundamental law of nature

known as the
first law of thermodynamics.

And the fact that energy is neither
created nor destroyed

has a profound implication.

İt means energy is eternal.

The energy that's here now
has always been here.

And the story of the evolution
of the universe

is just the story of the transformation
of energy from one form to another,

from the origin of the first galaxies
to the ignition of the first stars

and the formation of the first planets.

Every single joule of energy
in the universe today

Was present at the Big Bang
13.7 billion years ago.

Potential energy held
in primordial clouds of gas and dust

Was transformed into kinetic energy,

as they collapsed to form stars

and planetary systems
Jjust like our own solar system.

In the sun, heat from the collapse
initiated fusion reactions at its core.

Hydrogen became helium.

Nuclear binding energy was released,
heating the surface of the sun,

producing the light that began
to bathe the young Farth.

And at some point in that story,
around four billion years ago,

that transformation of energy
led to the origin of life on Earth.

Around 350 kilometres
south of Sagada, this is lake Taal.

Despite its sleepy languid appearance,

this landscape has been
violentiy transformed by energy.

When I think of a volcano,
I usually think

of a pointy, fiery mountain
with a little crater in the top.

Probably a bit like that one.

But, actually, this entire lake is
the flooded crater of a giant volcano.

It began erupting only about
140,000 years ago.

And in that time, it's blown 120 billion

cubic metres of ash and rock
into the Earth's atmosphere.

This crater is 30 kilometres across

and, in places, 150 metres deep.

I mean, that's a cube of rock

five kilometres by five kilometres

by five kilometres just blown away.

İt's a big volcano.

Taal lake is testament
to the immense power

locked within the Earth
at the time of its formation.

Since the lake was createdi,
a serles of further eruptions

formed the island in the centre.

And at its heart is a place
where you can glimpse the turmorl

of the inner Farth,

where energy from the core
still bubbles up to the surface,

producing conditions similar

to those that may have provided
the very first spark of life.

Now, the water in this lake is different
from drinking water

in a very interesting way.

See, if I test this bottle of water

with this, which is called
universal indicator paper,

then you see immediately
that it goes green.

And that means that
it's completely neutral.

İt's called pH 7 in the jargon.

Then, look what happens when
I test the water from the lake.

Now the indicator paper stays orange,

in fact, it might have gone
a bit more orange.

So, that means that this is acid.
İt's about pH 3.

At the most basic level,

the energy trapped inside the Earth
is melting rocks.

And when you melt rock like this,
you produce gases.

A lot of carbon dioxide.

And, in the case of this volcano,
a lot of sulphur dioxide.

Now, sulphur dioxide dissolves in water

and you get H2SO4, sulphuric acid.

Now, what do I mean
when I say that the water is acidic?

Well, water is H20, hydrogen
and oxygen bonded together,

but actually when it's liguid,
it's a bit more complicated than that.

İt's actually a sea of ions.

So, H plus ions.
That's just single protons.

And OH minus ions. That's oxygen
and hydrogen bonded together.

ALI floating around.

Now when something is neutral,
when the pH is 7,

then that means that the concentrations
of those ions are perfectly balanced.

When you make water acidic,

then you change
the concentration of those ions,

and, to be specific,
you increase the concentration

of the H plus ions, of the protons.

So, this process
of acidification has stored

the energy of the volcano
as chemical potential eneragy.

The volcano transforms heat
from the inner Earth

into chemical energy and stores it
as a reservolrr of protons in the lake.

And this is the same way energy
is stored in a simple battery

or fuel cell.

These bottles contain a weak acid,

and are connected by
a semi-permeable membrane.

Passing an electric current through them
has a similar effect

to the volcano's energy
bubbling up into the lake.

İt causes protons to builld up
in one of the bottles.

You can think ofit, I suppose,
like a waterfall

where the protons are up here
waiting to Tlow down.

And all you have to do
to release that energy

and do something useful with it
is complete the circuit.

Which I can do

by just connecting a motor to İt.

There you go. Look at that.

That's the protons cascading down
the waterfall,

and driving the motor around.

(CHUCKLES) It actually works.

GOuite remarkable, actually.

Now, the fuel cell produces and exploits
its proton gradient artificially.

But there are places on EFarth

where that gradient occurs
completely naturally.

Here, for example.

So, we've got the proton reservoir
over there, the acidic volcanic lake.

If you look that way,
there's another lake

and the reaction of the water
with the rocks on the shore

make that lake slightly alkaline,
which is to say that there's a deficit

of protons down there.

So, here's the waterfall.

Reservoir of protons up there,
the deficit down there.

If you could just connect them,

then you'd have a naturally
occurring geological fuel cell.

And it's thought

that the first life on our planet
may have exploited the energy

released in those
natural proton waterfalls.

(CHİLDREN SHOUTING, LAUGHING)

What do you think? It's good, isn't it?

These are pictures from deep below
the surface of the Atlantic Ocean,

somewhere between Bermuda
and the Canarles.

And it's a place known as the Lost City.

You can see why. Look at these.

Huge towers of rocks, some of them
50, 60 metres high,

reaching up from the floor
of the Atlantic and into the ocean.

İt's what's known as
a hydrothermal vent system.

So these things are formed
by hot water and minerals and gases

rising up from deep within the Earth.

The reason it's thought that life
on Earth may have begun

in such structures is because
these are a very unigue kind

of hydrothermal vent
called an alkaline vent.

And about four billion years ago,
when life on Earth began,

sea water would have been mildly acidic.

So, here is that proton gradient,
that source of energy for life.

You've got a reservoir of protons
in the acidic sea water

and a deficit of protons
around the vents.

And the vents don't just provide
an energy source.

They're also rich
in the raw materials life needs.

Hydrogen gas, carbon dioxide

and minerals containing iron,
nickel and sulphur.

But there's more than that.
These vents are porous.

There are little chambers inside them

and they can act to concentrate
the organic molecules.

You've got everything
inside these vents.

You've got concentrated building
blocks of life trapped inside the rock.

And you've got that proton gradient.

You've got that waterfall
that provides the energy for life.

So this could be
where your distant ancestors come from.

Places like these could be
the places where life on Earth began.

The first living things
might have started out

as part of the rock that created them.

Simple organisms

that exploited energy from the naturally
occurring proton gradients in the venits.

And we think this because
living things still get their energy

using proton gradients today.

Deep within ourselves,

the chemistry the first life
exploited in the vents

is wrapped up in structures
called mitochondria.

Microscopic batteries

that power the processes of life.

This is a picture

of the mitochondria
from a little brown bat.

This is the picture of mitochondria
from a plant.

İt's actually a member
of the mustard family.

This, a picture of mitochondria
in bread mould.

And this, mitochondria inside
a malaria parasite.

So, the fascinating thing

is that all these animals and plants

and, in fact, virtually
every living thing on the planet

uses proton gradients
to produce energy tolive.

Why?

Well, the answer is probably

because all these radically
different forms of life

share a common ancestor.

And that common ancestor
was something that lived

in those ancient undersea vents
four billion years ago,

where naturally-occurring
proton gradients provided the energy

for the first life.

So, if you are looking
for a universal spark of life,

then this is it.

The spark of life is proton gradients.

In those four billion years,
that spark has grown

into a flame.

And a few simple organisms

clustered around a hydrothermal vent

have evolved to produce
all the magnificent diversity

that covers the Farth today.

(RUMBLING)

Today, life on Earth is so diverse.

İt covers so much of the planet,
that you can find places like this lake.

I mean, it's effectively
its own sealed ecosystem.

İt's salt water.
It's connected to the sea.

But it's only connected through
small channels through the rock.

So that means that the marine life
in the area is effectively isolated.

(BIRDS CHIRPING)

This is the golden jellyfish,

a unigğue subspecies only found
in this öone lake on this öone island

in the tiny Micronesian
Republic of Palav.

They used to live like most jellyfish.

Cruising the open ocean,
catching tiny creatures,

zooplarıkton, in their long tentacles.

But today, their tentacles
have all but disappeared.

Because the golden jellyfish
have evolved to do something

that very few other animals can do.

İt really is incredible.

There are... I want to say, millions
of jellyfish

as far as you can see,
all the way down

till the... till the light vanishes,
there are jellyfish.

And you can see them congregating
in the sun. If you go over there

to where the lake's in shade,
there are just none.

And then, in this pool of light

beneath the sun,
there are millions of them.

Beautifully elegant things
just floating around.

(CHUCKLES)

I'm not being unduly hyperbolic.
İt's gulite remarkable.

(MUFFLED MUMBLING)

This lake is home to
over 20 million jellyfish,

whose success comes down
to a remarkable adaptation.

Their bodies play host to
thousands of other organisms.

Photosynthetic algae that harvest
energy directly from sunliğht.

The jellyfish engulf the algae
as juveniles.

And, by adulthood, algal cells make up
around 1096 of their biomass.

Grouped into clusters
of up to 200 individuals,

they live inside
the jellyfish's own celis.

The gölden jellyfish uses algae to get
most of its energy from photosynthesis.

The ones at the surface are gentiy...

Wow! There's one there.
They're gently turning.

The reason they do that
is to give all their algae

an eğual dose of sunlight.

So they are guite democratic creatures,
just making sure

they get as much food as they can.

And they just come up to you

jellying around,

photosynthesising.

They tell me they don't sting.

But I'm sure I've got a tingling finger.

And it's not just their anatomy that's
adapted to harvest solar energy.

Every morning, as the sun rises,

the jellyfish begin to swim
towards the east.

And as the sun tracks across the sky,
they move back again

towards the west
where they spend their night.

So, the jellyfish have this...

beautiful, intimate
and complex relationship

with the position of the sun in the sky.

As sunliğht is captured by their algae,

it's converted into chemical energy.

Enerogy they use
to combine simple molecules,

Water and carbon dioxide,

to produce
a far more complex one -

glucose.

Önce absorbed by the jellyfish,
glucose and other molecules

not only power their daily voyage
across the lake,

they provide the basic building blocks
the jellyfish use to grow

the elegant and complex structures
of their bodies.

So the jellyfish,
through their symbiotic algae,

absorb the light, the energy from
the sun, and they use İt to...

to live,
to power their processes oflife.

And that's true, directly or indirectly,

for every form of life
on the surface of our planet.

But things are a little bit
more interesting than that,

because energy
is neither created nor destroyed.

So life doesn't eat it somehow.

İt doesn't use İit up.
It doesn't remove it from the universe.

So what does it do?

To understand how energy sustains life,

you have to understand exactiy
what happens to it

as the cosmos evolves.

In the first instance
after the Big Bang,

there was nothing in the universe
but energy.

(RUMBLING)

As it changed from one form to another,

galaxies, stars and planets were born.

But while the total amount of energy
in the universe stays constant,

With every single transformation,

something does change.

(CRACKLING)

The energy itself becomes
less and less useful.

It becomes ever more disordered.

And you can see this process in action

as energy from the sun hits
the surface of the Farth.

Think about this sand on the beach. It's
been under the glare of the sun all day.

İt's been absorbing its light,
which has been heating it up.

And now that the sun is dipping
below the horizon,

then the sand is still hot to the touch.

Because it's reradiating all the energy
that it absorbed as heat

back into the universe.

And the keyword there is "all".
AILL the eneragy.

See, ifit didn't do that, then it would
just gradually heat up

day after day after day and eventually,
I suppose, the whole beach would melt.

So, what's changed?

Well, it's the guality of the energy,
if you like.

I mean, think about it.

If as much energy
was coming back off this sand now

as İit absorbed from the sun, then
it should be giving me a suntan.

Right? I should need sun creamif I sit
looking at this beach all night

and obviously I don't.

The difference is that this energy
is of a lower guality.

It can do less.

İt's heat, which is a very low guality
of energy indeed.

So what the sand's done

is take highly-ordered,
high-guality energy from the sun

and convert it to an egual amount
of low-guality, disordered eneragy.

(WAVES CRASHING)

Ihis descent into disorder
is happening across the entire universe.

(EXPLODING)

As time passes,
every single joule of energy

is converted into heat.

The universe gradually cools
towards absolute zero

until with no öordered energy left,

the cosmos grinds to a hallt...

and every structure in it decays away.

Yet whilst the universe is dying,

everywhere you look, life goes on.

İt's a deep paradox
that Schrodinger was well aware of

when he wrote his book in 1943.

"How can it be," writes Schrodinger,

"that the living organism avoids decay?"
In other words,

how can it be that life
seems to continue to build

increasingly complex structures

when the rest of the universe
is falling to bits, is decaying away?

Now, that's a paradox

because the universe is falling to bits.

İt is tending towards disorder.

That is enshrined in a law of physics
called the second law of thermodynamics.

And I think most physicists believe

that it's the one law of physics
that will never be broken.

The key to understanding how life
obeys the laws of thermodynamics

is to look at both
the energy it takes in

and the energy it gives out.

This is a thermal camera,
so hot things show up as red

-and cold things show up as blue.
-(COCK CROWING)

So what you're seeing here

is that the chicken
is hotter than its surroundings.

Now heat is a
highly-disordered form of eneragy.

So the chicken is radiating disorder

out into the wider universe.

By converting chemical energy into heat,

life transforms energy from an öordered
to a disordered form

in exactiy the same way as every other
process in the universe.

(COCK CROWING)

In fact, every single
human being generates

6, 000 times more heat
per kilogram than the sun.

And it's by converting so much energy
from one form to another

that life is able to hang on

to a tiny amount of order for itself.

Just enougğh to resist the inevitable
decay of the universe.

So it's no accident
that living things are hot

and export heat to their surroundings,

because it's an essential part
of being alive.

The living things borrow order
from the wider universe

and then they export it again
as disorder.

But it's not precisely in balance.
They have to export more disorder

than the amount of order they import.

That is the content of
the second law of thermodynamics.

Living things have to obey
the second law

because they're physical structures.

They obey the laws of physics.

Just by being alive

we too are part of the process
of energy transformation

that drives the evolution
of the universe.

(RUMBLING)

We take sunliğht that has its origins
at the very start of time

and transform it into heat

that will last for eternity.

So far from being a paradox,

living things can be explained
by the laws of physics.

The very same laws that describe
the falling of the rain

and the shining of the stars.

The dragonfly draws its energy
from proton gradients,

the fundamental chemistry
that powers life.

But the real miracles are the structures

they build with that energy.

Borrowing order to generate cells,

arranging those cells into tissues

and those tissues into the intricate
architecture of their bodies.

So we've developed a guite
detailed understanding

of the underlying machinery
that powers these dragonflies

and, indeed, all life on Earth.

And, whilst we don't have
all the answers,

it is certainly safe to say
that there's no mysticism reduired.

You don't need some kind
of magical flame

to animate these little machines.

They operate according
to the laws of physics.

And I think they are no less
magical for that.

Yet the dragonfly will only maintain
this delicate balancing act for so long.

Because all living things
share the same fate.

Fach individual will die.

But life itself endures.

This is because there's something
that separates life

from every other process
in the universe.

(BIRDS CHIRPING)

(ELEPHANT TRUMPETIİNG)

This is the Malaysian state of Sabah

on the northern tip
of the island of Borneo.

It's öone of the most
biodiverse places on the planet.

Home to 15,000 plant species,

3,000 species of tree,

420 species of bird

and 222 species of mammals,

-including those.
-(TRUMPETS)

(ELEPHANT ROARS)

Borneo's rainforests contain trees

that are thought to live
for more than a thousand years.

But the forest itself has existed
for tens of millions of years.

The reason it persists is because
each generation of animal and plant

passes the information
to recreate itself

on to the next generation.

And that's possible

because of a molecule found
in every cell of every living thing.

A molecule called DNA.

Now, all I need to isolate my DNA
is some washing-up liguid...

a bit of salt...

and the chemist's best friend...

vodka.

Now, to get a sample of DNA,

İ can just use myself.
If I just swirl my tongue around

on the edge of my cheek,

I'll dislodge some cheek cells
into my saliva.

(CHUCKLES) I missed the test tube.

There we are.
İt's a physicist doing an experiment.

(CHUCKLING)

Then...
I add a bit of washing-up liguid.

Now, what this will do...

is it will break open those cheek cells

and it will also degrade the membrane
that surrounds the cell nucleus

that contains the DNA.

Salt will encourage the molecules
to clump together.

DNA is insoluble in alcohol.

So you should get a layer...

of alcohol...

with the DNA molecules precipitated out.

Yeah.

There, can you see?

Those strands of white.

And so, in that cloudy,
almost innocuous-looking solid,

are all the instructions needed

to build a human being.

So that is what makes life unigue.

Only living things have
the ability to encode

and transmit information in this way.

And the conseguences of that
profoundly affect our understanding

of what it is to be alive.

This rainforest is part of
the Sepilok Forest Reserve.

And in here somewhere are some
of our closest genetic relatives.

COX: Shh. Shh.

Oh, yeah. There. Can you see?

Orang-utans are highly specialised
for a life lived in the forest canopy.

Their arms are twice
as long as their legs.

And all four limbs
are incredibiy flexible,

each öone ending in a hand

whose curved bones are perfectliy
adapted for gripping branches.

These adaptations are encoded in
information passed down in their DNA.

(CHUCKLES) He's got a hat on.

He has actually just put a hat on.

(CHUCKLES)

This is the orang-utans' genetic code.

It was published in 2011.

And there are over
three billion letters in İt.

And if I flick through it...

Look at that.

Now, it's composed
of only four letters - A, C, T and G,

which are known as bases.

They're chemical compounds.
They're molecules.

And the way it works
is beautifully simple.

They are grouped into threes
called codons.

And some of them just tell
the code reader, if you like,

how to start or where to start
and where...

-(LEAVES RUSTLING)
-...and when it's gonna stop.

(COX CHUCKLES)

He's fast. (CHUCKLES)

So you would have a start and a stop

in between each group of three
codes for a particular amino acid.

Now amino acids
are the building blocks of proteins

which are the building blocks
of all living things.

So you would just read along.
You would find a start-stop.

And then you would go along in threes.
Build amino acid, build amino acid,

build amino acid, build amino acid.

Stitch those together into a protein.
And if you keep doing that,

eventually, you will come out
with one of those.

İ mean, it's not that simple, of course.

But the basics are there.

This code written in there...

are the instructions to make him.

To faithfully reproduce
those instructions,

for generation after generation,

the orang-utans,
and indeed all life on Farth,

rely on a remarkable property of DNA.

Its incredible stability
and resistance to change.

Every time a cell divides,
its DNA must be copied.

And the genetic code
is highly resistant to copying errors.

The little enzymes, the chemical
machines that do the copying,

on average make only one mistake
in a billion letters.

I mean, that's like copying out
the Bible about 280 times

and making just one mistake.

That fidelity means adaptations
are faithfully transmitted

from parent to offspring.

And so while we think of evolution
aS a process of constant change,

in fact, the vast majority
of the code is preserved.

So even though we are separated
from the orang-utans

by nearly 14 million years of evolution,

what's really striking is
Just how similar we are.

And those similarities
are far more than skin-deep.

Orang-utans are surely one
of the most human of animals.

And they share many of the behavioural
traits that you would define

as being uniguely human.

They nurture their young for eight years

before they let them go
on their own into the forest.

In that time, the infants learn
which roots are safe to eat

and which are poisonous,

which branches will hold their weight
and which won't.

And they can do all that
because they have memory.

They can remember things
that happened to them in their life.

They can learn from them
and they can pass them on

from generation to generation.

And that deep connection extends
far beyond our closest relatives

because our DNA contains the fingerprint

of almost four billion years
of evolution.

(BIRDS CHIRPING)

If I draw a tree of life
for the primates,

then we share a common ancestor
with the chimps and bonobos.

About four to six million years ago.

And if you compare
our genetic seguences,

you find that our genes
are 9996 the same.

We go back to the split

with gorillas, about six to eight
million years ago,

and, again, iİf you compare our genes

then you find that they are
98.496 the same.

Back in time again.

Common ancestor with our friends
over there, the orang-utans,

then our genes are 97.496 the same.

And you could carry on
all the way back in time.

You can look for our
common ancestor with a chicken

and you'd find that our codes
are about 6096 the same.

And, in fact, if you look for any animal
like him. A little fly or a bacteria,

something that seems superficially
completely unrelated to us,

then you will still find seguences
in the genetic code

which are identical
to seguences in my cells.

So this tells us that all life on Earth
is related. It's all connected

through our genetic code.

DNA is the blueprint for life.

But its extraordinary fidelity
means it also contains a story.

And what a story it is.

The entire history of evolution

from the present day, all the way back
to the very first spark of life.

And it telis us that we're connected.

Not only to every planet
and animal alive today,

but to every single thing
that has ever lived.

The guestion "What is life?" is surely
one of the grandest of guüestions.

And we've learnt that life
isn't really a thing at all.

İt's a collection of chemical processes

that can harness a flow of energy
to create local islands of order,

like me and this forest,

by borrowing order
from the wider universe.

And then transmitting it from
generation to generation

through the elegant chemistry of DNA.

And the origins of that chemistry can be
traced back four billion years,

most likely to vents
in a primordial ocean.

And, most wonderfully of all,
the echoes of that history

stretching back for a third
of the age of the universe

can be seen in every cell
of every living thing on Earth.

And that leads to what I think is
the most exciting idea of all.

Because far from being some chance event
ignited by a mystical spark,

the emergence of life on Earth

might have been an inevitable
conseduence of the laws of physics.

And, if that's true,

then a living cosmos
might be the only way our cosmos can be.

(GALAXY DNA SONG PLAYING)