All language subtitles for BBC.How.to.Grow.a.Planet.2of3.The.Power.of.Flowers.PDTV.x264.AC3.MVGroup.org.eng

I've spent most of my life
trying to understand

the forces that shaped our planet,

and as a geologist,
it always seemed to me

that rocks were right
at the heart of things.

But now, I'm discovering it's not
only volcanoes
and colliding continents

that have driven
the Earth's greatest changes,

because at crucial moments
in its history,

another force has helped create
the planet we live on...

...plants.

It's a whole new story
about the Earth,

revealing how,
from its earliest history,

plants have shaped our world.

So far, we've seen how plants
and their ancestors began

by producing
our life-giving atmosphere.

I'm breathing oxygen that was made
two-and-a-half billion years ago.

They'd harnessed light from the sun,

bringing energy to the world.

And they'd formed the fertile soil,

allowing life to colonise the land.

But the next chapter
will take us even further,

because a powerful newcomer
to the plant world was on its way.

It would conquer every corner
of the planet.

It would shape the very surface
of the Earth

and it would drive the evolution
of animal life,

including our own ancestors.

This is its story.

These buildings are
nearly 1,000 years old.

The largest religious site
in the world,

covering 200 square kilometres.

This is the temple of Angkor Wat
in Cambodia.

I am here to witness the importance

of one of the most powerful symbols
known to humankind.

A symbol central to an ancient
Buddhist ceremony.

Flowers.

(BUDDHIST CHANTING)

You see lotus flowers and jasmine
just arranged beautifully up there.

The lotus are the big ones
and the jasmine the trail
of little flowers.

See how the lotus petals are all
folded in amongst themselves,

the different layers representing
the various levels of heaven.

For these monks,
flowers have a crucial role.

And this is just one ceremony
from one religion.

Flowers are central to cultures
throughout the world.

They're deeply woven
into all our lives.

But it's not only a human obsession.

Because since they evolved,

flowers have been the driving force
for the whole of life on Earth.

They've become enmeshed
in the lives

of virtually the entire animal
kingdom in all its rich diversity.

From the smallest insect to
some of the largest mammals,

they've all been shaped by flowers.

But how did this happen?

And why?

The emergence of flowers

is one of the biggest turning points
in Earth's history.

To understand how
they changed our planet,

we need to go right back
to a prehistoric time...

...to the moment when
the very first flower appeared.

Up until around 140 million years
ago, the Earth was very different.

The animal kingdom was dominated
by dinosaurs.

And the separate continents
we know today didn't exist.

Instead, there had been a single
huge continent, Pangaea.

I'm heading for a place that's about
as close as you can get

to that ancient supercontinent.

It's in the remote South Pacific,
1,500km from Australia.

The island of New Caledonia.

It looks like Paradise, doesn't it?

What makes New Caledonia
just so interesting

is that it's like a Noah's Ark
of ancient plants.

This little journey is going to take
us back in time 140 million years.

Because this part of the world
is so isolated,

it gives a glimpse of the plant
world before flowers existed.

Back then, the plant kingdom
had two mighty rulers.

One of them was the tall conifers,

like this prehistoric species
of pine.

Look at these trees.
Bizarre, aren't they?

They're huge.

Araucaria, Cook pine,

named after Captain Cook
who explored this corner
of the world.

Pine trees are a family of conifers
that are amongst the oldest
in the world

so when the dinosaurs were around,
these were nature's real giants.

What made flowers so revolutionary

was the limitations of the ancient
plants that came before them.

To reproduce, conifers like these
relied on the vagaries of the wind.

This is pollen, the male sex cells
of conifers.

Each grain has to be magnified
1,000 times to really see it.

The two air sacs, one in each side,
catch the breeze.

With luck, the male pollen
will be blown

to a female cone on a nearby tree.

But for that to happen,
each conifer needs vast amounts.

It's very wasteful.

Up to 10 billion grains have to be
released by a single tree.

The other big player back then
was the ferns.

Their method of reproduction
was also restricting.

Because ferns evolved in wet,
swampy conditions,

they needed water to transport
their sex cells.

And they use a surprising device.

What they do is they release
a sperm,

which swims through the water
and mud to a nearby plant

and fertilises the egg.

Under a microscope, you can see
that by thrashing around,

the male sperm cell can propel
itself through water.

It's able to swim
for over two hours.

It's amazing to think that a plant

produces something
like a human sperm.

But the downside was that ferns
had to live near water.

It was hugely limiting.

All this meant something was lacking
in the world of Pangaea...

..diversity.

There were few species of ferns
and even fewer types of conifers.

Just 1% of the range of plants
we have today.

And the animal kingdom
was also limited.

Scientists have found evidence
of 700 different dinosaurs.

It sounds a lot,

but today there are over 5,500
species of mammals alone.

There was little variety.

It was a monotonous green world.

And that's how life on the planet
would have continued.

140 million years ago,
somewhere in Pangaea,

one plant of one species happened to
chance on a new way of reproducing.

And it would change the Earth
for ever.

I've pushed further into
New Caledonia's jungle.

The plant I'm after is really rare,
which is why I've come so far.

This is the only place that you find
it. It's died out everywhere else.

Mind you, amongst all of this,
it's like a needle in a haystack.

Hang on a minute.

That looks like the leaves.

That wood.

Got them.

I've come all the way round
the world to find that.

That is the Amborella plant.

Amborella trichopoda
is the closest living relative

of the first flower to evolve.

All flowers today have descended
from its ancestor.

Botanists believe it began
when a single plant mutated

to have leaves that became petals
which, instead of being green,

were probably white
like those of Amborella.

We now consider them to be
the very first petals
of the very first flower.

To grasp the significance of this
plant, you have to imagine a scene

in some primordial forest where
everything's just completely green.

And then there's this flash
of colour and glint of white.

Some chance mutation.

And the thing is that scurrying
amongst it is a little beetle.

Certainly not a bee because
bees hadn't evolved yet,

but a beetle spies this dash
of white and scurries across
to have a look.

And then munches
on these little white buds

that are just packed full of pollen.

But not all the pollen is eaten.

Some sticks to the beetle,
and on it goes to other plants.

Unknowingly, it's become a courier,
delivering pollen
from plant to plant,

pollinating them
as it looks for food.

Plants had evolved
an ingenious way of reproducing

that no longer relied
on haphazard methods,

like the wind for conifers
or water for ferns.

Instead it was reliable.

Insects carried pollen directly
to other plants.

It was the birth of flowers.

It's hard to grasp just how
revolutionary this was.

I'm used to thinking of momentous
changes in the Earth

as occurring through huge events -

vast continents colliding
or mountains uplifting,

but this was the tiniest of events.

A subtle alteration
of how a plant looked

and a chance encounter
with a curious beetle.

And on the back of that,
the world changed for ever.

Back then, the supercontinent
of Pangaea was splitting up.

Smaller continents were forming...

...creating countless new
landscapes...

..with new climates
and environments -

rising mountain ranges...

..and dry inhospitable deserts.

For conifers and ferns,
so dependent on wind and water,

the new landscapes
were impregnable.

But for flowering plants, it was
the chance they'd been waiting for.

Because they had a powerful
in-built advantage.

This is a monkey puzzle tree.

Like most conifers, monkey puzzles
live for hundreds of years,

and crucially, they don't reach
sexual maturity till they're 40.

Now...this is a campion flower,

which in the shadow of this thing
looks pretty puny,

but the campion flower
has the last laugh

because this, like most flowers,
matures much quicker.

In fact, the campion flower can
reproduce after just four months.

It means that in the time
that it takes this conifer

to produce just one generation,

the flowers can go through
120 generations.

What's so fascinating is the impact
that this has got on evolution

because every time
there's a new generation,

there's a possibility
of a genetic mutation,

a mutation that might give a
characteristic that helps survival.

So the faster the life cycles,

the more species can adapt
to new environments,

which, of course,
is crucial to our story.

140 million years ago,
these rapid life cycles

helped flowers exploit
the most hostile environments.

Just like Tankwa Karoo
in South Africa.

Because beneath this desert
is a hidden carpet of flowers.

Each year, it rains
for just two months.

The plants only have
this brief window to reproduce.

So how do they ensure
they are pollinated in time?

They evolved colour.

Each type of flower that you see
is using colour

in a struggle to get noticed
by insects.

And there isn't much time.

In a few weeks or days
the rains will be gone,

and if these flowers aren't
fertilised by then,
the plants will die

and the opportunity to reproduce
will be lost.

Hundreds of different flowers,
dozens of different colours,

whether it be orange gazanias,

purple dew flowers,

or the red balloon pea plant.

And it wasn't random.

Many used a different specific
colour to attract insects.

They became targets,

using insects to transfer
the right pollen to the right plant,

even over great distances.

And flowers evolved a clever way
to enhance this colour.

To the naked eye,
a petal looks smooth.

But magnify it 1,000 times
and you can see its real structure.

It's not a flat surface at all.

Instead, the petal is made up
of countless nodules.

Each acts like a tiny prism,
which reflects and diffracts light.

It gives the petal an iridescence,
to attract passing insects.

And in their use of colour,
flowers went even further.

It's a heck of a contraption,
isn't it?

A special camera to give you
a kind of...

insect's view of what
a flower looks like.

That's nice. Look at that.

Insects and this camera

can see a part of the light spectrum
called ultraviolet

that's normally invisible
to us humans.

The camera reveals how flowers
that appear plain to us

look completely different to insects

And the markings
are really important

because they are like
airport runway lights

that guide the insect down
onto the petals.

Like neon signs that say
"free food here".

But once the flowers
were pollinated, they still faced
a big challenge

because their offspring
then had to make it through
the rest of the year.

Here in the Karoo, that could be
ten months of drought.

To survive, flowers perfected
another trick,

which had a powerful impact
on life on Earth.

Seeds.

Because seeds have
this remarkable ability

that we don't normally think about.

These are seeds of the Canna
indica flower, and this...

This is an empty shotgun cartridge.

I'm going to pack the seeds in where
the lead pellets would have been.

(GUNSHOTS)

(BANG)

Oh! It's gone right through.

Look at that!

That looks perfectly intact.

The story goes that during
the Indian Mutiny
of the 19th century...

soldiers used these seeds
instead of lead shot.

They're hard enough to be blasted
out of a barrel and through wood.

These seeds are so tough, in fact,

that it's said that despite being
fired from a gun,
they can still germinate.

Sounds unlikely, I know,

though we'll see.

But a tough shell wasn't all,
because seeds from flowering plants

developed a further
evolutionary advantage

that no other plant possessed.

It all starts at the moment
of pollination.

Having been delivered by an insect,

two cells from the pollen burrow
deep into the flower's ovary.

Here, one fertilises an egg
to create an embryonic plant.

But, and here's the clever bit,

the second cell from the pollen
does a completely different job.

Instead of becoming a new plant,

it grows into a food source
for the fertilised egg.

A kind of packed lunch.

It's called double fertilisation

and it's unique
to the seeds of flowers.

It meant seeds could lie dormant
for months or even years

until conditions were right.

As for my Canna indica seeds,
well, this is how they fared.

Despite being blasted
from a shotgun,

four weeks later,
here they are now...

..successfully germinating
into a tiny flowering plant.

Remarkable!

By 100 million years ago,

flowers were redrawing the global
map of where plants could live.

They were turning once infertile
areas into oases of life.

And it wasn't just about plants.

Because these flower oases were now
luring animals, too.

There was one ability above all
that gave flowers the power
to do this.

Plants can do something unique

that marks them out amongst all
other living things on the planet.

Their leaves can capture energy
from our nearest star, the sun,

and turn it into food.

And the total amount of energy
photosynthesis brings to the Earth

is staggering.

I know this is a bit odd,

but just imagine
that this little scooter
and all the fuel that it uses

represents all the energy that
the USA consumes in just one year.

Now imagine that you take
all the plants in the world,

all the trees,
flowers and grasses...

..all the jungles, forests
and savannas

and you add up the total energy

harnessed by plants
from the sun every year.

It's not two scooters' worth or ten.

It's all of this.

40 times the amount of energy
consumed by America every year.

It's 100 trillion watts
of energy every year.

Astonishing as this is,
flowers took all this energy
and went even further.

An adaptation that would have
enormous repercussions

for the animal kingdom.

They developed this
ingenious method

of making the sugars available
to their pollinators,

and if I take this syringe here
and just slide it delicately
in here...

..I can show you
what they came up with.

It's this really sweet-tasting
liquid, nectar, of course.

One of the most energetic sources
of food on the planet

and something animals found
utterly irresistible.

The nectar from this
bird of paradise flower

has three times the sugar
concentration of Coca-Cola.

Flowers were now pumping bite-sized
packets of liquid energy

into the food chain.

And this began driving the evolution
of entirely new insects.

Just take a look at this.

Isn't it beautiful?

For me, this is one of the most
incredible fossils ever found.

It's such intricate detail.

The material is amber.

And inside it is a bee.

It's a very primitive bee
that got stuck in liquid tree resin

which then solidified
and preserved the hapless insect.

Bee fossils like these
began appearing
roughly 100 million years ago.

And what they show
is the incredible impact

flowering plants were now
having on evolution.

What I love about this fossil
is that it's like a snapshot
of an ancient past,

just captured in time.

And it makes you realise that
there was a particular point

when bees first arrived on Earth.

Bees evolved from carnivorous wasps

which had turned their backs on meat
in favour of pollen and nectar.

As they evolved, their whole bodies
became covered in hair,

to collect more pollen.

They developed sophisticated
compound eyes,

with hundreds of tiny lenses
to spot the flowers.

Inside were special cells
to detect UV light.

There are more types of early bees
in South Africa

than anywhere else in the world so
it's thought they originated here.

And if you think about it,

without the power of flowers,
you'd have no bees at all.

But by creating insects
to pollinate them,

the flowers introduced
a new problem for themselves.

There was a risk that after
an insect picked up pollen
from a flower,

it would then travel on to
a different species of flower
and fail to fertilise it

The pollen would be wasted.

The solution of flowers
was inspired.

Down under these cliffs
on the South African coast,

you can see what they came up with.

This lovely pink flower
is Orphium frutescens...

..which flourishes here in these
salty conditions near the sea,

but what's truly amazing
about this plant

is that it's struck
up this exclusive relationship
with a particular bee.

Orphium flowers
don't contain nectar.

The payment they provide is pollen.

But strangely,
they keep it locked up.

Special twisted stamens stop it
being stolen by visiting insects.

All, that is, except one -

the female carpenter bee.

Only she has the key.

Let me show you what the bee has to
do, using these tuning forks here.

When the bee lands on the flower,

it changes the rate at which
it beats its wings to just
the right frequency.

From this note...

(HIGH NOTE)

..to this one.

(LOWER NOTE)

Middle C.

And it's these vibrations that are
the key to unlocking the stamens

which open up at the top here and
just shower the bee with pollen.

(TUNING FORK BUZZES)

Ah! Look at that.

Look at the amount of yellow pollen
on there. Fantastic!

(BEE BUZZES)

Now watch the bee do the same,

hitting the middle C note...

(BUZZING DROPS)

..with the beat of its wings...

..and unlocking the pollen.

No other insect does this.

It's incredible, isn't it?

One single species of flower,
one particular type of bee

have evolved together
to give this intimate partnership.

It ensured that a flower's pollen
was successfully taken

to a plant of the same species.

But these increasingly
tight relationships

between insects and flowers
had another impact on life on Earth.

Because they led to tighter
and more isolated populations,

that started creating gaps
in the overall ecosystem.

This, in turn, encouraged
new species to evolve,
filling in those spaces.

Flowers were now driving a huge
increase in the diversity of life.

And they were fuelling this increase
by pumping nectar
into the food chain.

The insects, bees, butterflies
and moths, such as the hawk moth,

were eating it with long,
probing tongues.

There were new species of birds,
like the Calliope hummingbird,

with beaks perfect
for trumpet-shaped flowers.

And predators, such as
these toucans, that ate
the pollinators.

Between 120 and about
90 million years ago,

all thanks to flowering plants,

evolution had entered
the most explosive phase
in the Earth's history.

By now Pangaea had split up,

creating the continents
so familiar to us today,

and flowers dominated them.

They'd conquered the ancient
conifers and ferns,
and covered half the Earth.

But it wasn't just life
they were changing.

Because they started altering
the very shape of the planet itself.

This is Ha Long Bay in Vietnam.

I'm here because it's evidence
of how flowers unleashed

some of the most powerful
forces on Earth.

This whole landscape
just dwarfs you.

You can see these pinnacles
of limestone just soaring upwards,

limestone that you get
all over Vietnam.

And it gives this
really distinctive, even iconic
landscape called karst.

The thing is, when you look
at things as huge as that

you look for huge geological
processes to create them,

but it's not always the case.

That's because 90 million years ago,

flowers began to build an empire
across the planet...

..in a totally unexpected way.

They did it by creating vast
tropical rainforests.

Almost all the trees are really
giant flowering plants.

You can see one here in flower.

And all the trees
are doing one thing.

Breathe out on a piece of glass

and it's pretty obvious that
there's moisture in your breath.

And in a funny kind of way,
plants are breathing out
moisture too.

It's just much harder to see.

But take a look at this. If I tie
a clear plastic bag
over this big leaf,

then we should be able to actually
see the plant breathing away.

And all we need to do now is...
wait a couple of hours.

Look how much moisture this single
banana leaf produces.

It's losing water, or transpiring,

through tiny pores in the leaf
called stomata.

Close up, you can see the veins
of the leaf,

which transport water
around the plant.

Leaves of flowering plants contain
four times more veins

than other plants.

Because they share the same type
of special vein leaves,

trees like these act as kind of
giant water pumps

drawing moisture up from the soil
and pumping it into the atmosphere.

Some of these trees chuck out
five tonnes of water every day.

All this transpiration meant
that 90 million years ago,

flowering plants were creating
more clouds...

..which led to more rain.

(THUNDER CRACKS)

Water that, when it fell,

was then drawn up from
the forest floor by the same trees,

forming a self-sustaining cycle
of almost perpetual rainfall.

In fact, 80% of the water
in the rainforests

came from the flowering plants
themselves.

In this new age of rain,

water became an ever powerful
sculpting force.

And today, you can see its effects
in an astonishing hidden world.

Deep beneath the rainforest
in central Vietnam

are the caverns of Hang Son Doong.

We are the first British film crew
to explore them.

Hang Son Doong is the largest
cave passage ever discovered

anywhere on Earth.

This single cavern
is nearly two kilometres long.

All carved from solid rock
by nothing more than water.

All of which has trickled down
from a single source -

the vast jungle above.

It is a relentless force that has
carved out a dozen enormous caverns.

An underground monument
to the power of flowering plants.

And deep in this labyrinth is what,
for me, is perhaps the greatest

of all the wonders
of the plant world.

Here, at the heart of the cave,
a whole rainforest.

Where the roof has collapsed,

flowering plants have made
their home...

..200 metres below ground level.

It is like a lost world.

The thing is,
just a few minutes ago,
there was me in a cool, dark cave,

and then ejected into this place
with streaming sunlight.

Hot and sticky rainforest.

And where there's water and light,
flowers have produced life.

Plants such as this
banana flower thrive,

which in turn attracts butterflies
and other animals.

It's a thriving ecosystem here.

And the whole thing is fed, really,

everything, this whole food chain,
is fed by the flowering plants.

Flowering plants have created
a small but perfect version

of the rainforest above.

Look at that mist.

There's a whole weird microclimate
in here.

Clouds of moisture
envelope everything.

And the plants just soak up
that moisture,

just draw it up
and then pass it out.

So that cycle of transpiration

that we see on a big scale
up in the tropical forests

is captured in miniature down here.

Caves formed under all the world's
great rainforests.

And this extra water even began
to transform the global climate.

As water evaporates, it absorbs heat
and cools the planet.

The Amazon rainforest alone
keeps its whole region
five degrees colder.

Across the planet,
water injected into the water cycle

was eroding deep canyons,

carving high mountains,

and sculpting the karst towers
so iconic of Asia.

It's extraordinary, isn't it?

Especially when you think
that all this

comes not from huge forces
deep underground,

but in part from tiny changes
on the leaves of flowering plants.

65 million years ago was
the age of the rainforests.

They'd spread from the equator
to cover most of the Earth.

It meant three quarters
of all plants were now flowers.

A rich, lush home for millions
of new animals.

The dominance of the flowering
plants seemed unassailable.

But it was not to last.

A 10km-wide asteroid coming
from deep space was on
a collision course.

It hit the Earth with a force
of a billion Hiroshima bombs.

70 billion tonnes of pulverised rock
were blasted into a low orbit.

Scientists called it ejector
and travelling at supersonic speeds

its friction with the atmosphere
heated the Earth up

by over 200 degrees Celsius.

It spontaneously triggered fires
across the land.

It was one of the worst mass
extinctions in the history
of the Earth.

And famously killed off
the dinosaurs.

But less well known
is the immediate impact on plants.

Scientists believe that for them,

the effect of the asteroid
was also devastating.

Not only were there fires,

but the ejector created clouds
of nitric and sulphur dioxide...

..which fell as acid rain...

..destroying plants
from the roots up.

I think it's really hard to imagine

what the most recent and powerful
extinction event must've been like,

but perhaps the closest you can get
to it is a newly-erupted volcano,

like here in White Island,
New Zealand.

I think it's just the desolation,
really.

The bleakness, that sense that
life's just been...obliterated.

For plants,

the aftermath of the asteroid impact
must have been similar.

Here on White Island,

vegetation has been incinerated
by successive eruptions.

And the volcanic fumes create
acid rain, just like after
the asteroid.

For flowering plants,
it was a disaster.

That close, almost inseparable
relationship with insects

was now their Achilles heel,

because even if a flowering plant
had survived the initial calamity,

it needed a specific animal
to pollinate it,

and often they'd simply
been wiped out.

But flowers weren't beaten yet.

All those evolutionary devices

that had allowed them to thrive
on a hostile planet
in the first place

now became their ultimate
tools for survival.

Coloured petals to attract
the few surviving pollinators.

Nectar to repay them
in desperate times.

Above all, flowers could rely on
those superb survival capsules

that could have been purpose-built
for just such an apocalypse...

..seeds.

Now, following the asteroid impact,

seeds helped flowers
to re-colonise the Earth.

And as they did so,

once again flowers formed
an inseparable relationship
with animals.

The dinosaurs had gone, but another
type of animal had replaced them...

..mammals.

This time, flowers used mammals
to help them distribute their seeds.

Here in Thailand, this whole
floating market celebrates

the clever evolutionary device
flowers came up with.

More sophisticated flowers
developed a really sneaky way

of spreading their seeds.

A method that didn't just disperse
at metres, but kilometres.

And to do that, they again harnessed
the hunger of animals.

They developed fruit.

What is that?

Durian. This is durian?

I cut. You taste. OK, yeah.

You can't come to Asia
without trying the smelliest,

most notorious fruit on Earth.

Beautiful!

I hope it tastes better
than it smells, though.

Ah! There's the seeds in there.

And then this flesh.

Texture's...

THEY LAUGH

They're all laughing.
They're laughing.

It's like an off avocado, really.

I think that's what they call
an acquired taste.

The botanical definition of a fruit

is that it must actually develop
from the flower itself.

The fleshy coating was once
the ovary, as it grew around
the maturing seeds.

Lovely. Incredibly sweet.

Very subtle.

Isn't that great? The way all
of them hide this inside,
this little seed.

You can see why some warm-blooded
mammal or bird

would want to eat this -
it's just packed with nutrition.

And of course, as you do that...

you...

you swallow the seed.

And then later on you pass that out
somewhere, miles away,

dumped in some little dollop
of manure.

But that's really the point
of all of these different types.

All this diversity is designed
to attract animals to eat it.

Fruit is one of the most remarkable
transformations in nature.

What begins as an advertisement
for an insect, a flower,

becomes a protective covering
for the seeds inside.

And then a final burst...
swells into the juicy flesh
of a fruit.

55 million years ago, one group
of early mammals was evolving

that relied almost entirely
on fruit.

In fact, without it, they'd probably
never have existed.

It was an animal which
would directly link flowers
to our human story.

They live here in Thailand's
Khao Sok National Park.

Somewhere in these trees
there are primates.

GIBBONS CALLING

I'm sure they're up there.

You see the trees just...
The branches moving but...

trying to pinpoint the actual
gibbons is...really tricky.

Oh, there's one.

Do you see it? It's kind of
silhouetted in the branches
just up there.

I'm sure it... Yeah, it's moving.

My first gibbon.

The primates - lemurs, monkeys
and apes -

evolved an inseparable partnership
with the fruit from flowers.

And it determined
their whole anatomy.

Primates have got the perfect tools
for reaching fruit.

They've got these really
strong hands which,

along with their powerful chest
and shoulder muscles,

allow them to get up into the trees.

All these are important traits
that we human primates
have inherited today.

And all came from the need

for the first primates to reach
the fruit of flowering plants.

Norberto Asensio is a primatologist.

He studies the crucial role fruit
plays in the diet of monkeys.

For most primates, fruit is
important. It's part of their diet -
so what?

Is it the core of the diet?
The essential core, do you think?

I would say so.

I would say that most of the primates
will have 70% to 90% of their diet

on fruit. It's quite a lot.

But back then, flowering plants
created a problem for themselves.

Primates were so hungry for fruit...

..they would pick it long before
the seeds inside were mature.

It meant seeds were being wasted.

So flowers came up with a solution.

When fruit was ripe, they made it
sweet, juicy and brightly coloured.

It was a colour-coded time delay.

And it encouraged primates to take
only fruit that was fully mature.

Norberto studies how
this colour coding

drove changes in
our ancient ancestors.

Before now, primates,
like all mammals, were colour-blind.

This made spotting ripe fruit
difficult, as I'm about to find out.

Let's do an experiment.

Here you have glasses that are going
to turn you into a simple mammal.

Let's see.

Oh, gosh!

The glasses simulate
colour blindness by removing
red from the picture.

I can kind of tell the difference
in contrast between some of them.

That's gone a very funny shade
of bluishness.

The interesting ones are these reds.

I know they're red but they
just don't seem red at all.

Overall it's just got a very...
almost bland greyness to it all.

For primates to perceive red,

they had to evolve a more
sophisticated vision system.

In the retina are special photo
receptor cells that detect colour,

called cones.

There are 150,000 per square mm.

Early mammals only had two types
of cone, one for green
and one for blue.

It meant they were colour-blind.

But primates evolved a third type.

It was sensitive to red.

Now they could spot ripe fruit.

Colour vision helped give primates
the advantage,

kick-starting the evolutionary
journey that resulted in us humans.

That's why we have colour vision now

and we have this wonderful
rainbow of colours

that we can see now and enjoy it.

Fruit drove the evolution
of so many of the traits
of our ancient ancestors,

but this simple need, the ability
to see if fruit was ready
to eat or not,

had given primates perhaps
for the first time on our planet

this capacity to see in full
glorious technicolour.

And it's something that I think
we just take for granted.

Since they'd evolved
140 million years ago,

flowers had transformed our planet.

They'd come to dominate
the plant kingdom,

sculpting the Earth itself.

Above all, flowers drove
the evolution of animals,

especially primates,

shaping our human evolution.

It seems to me that we are
rather animal-centric.

That by being members
of the animal kingdom ourselves,

we somehow see them as the thing
that's at the heart

of driving changes to life on Earth,

but I don't think that's true.

Most of the big changes
to life on the planet

have been brought around by flowers.

They are the ones that are more
manipulative, more inventive,

more powerful than any
of the animals that they
are interacting with.

Most animals are only here
because of flowers, including us.

It's an intriguing thought for next
time you're out doing the roses.

Next, we reveal the epic battle
between the forests

and their greatest challenger,
a new type of plant...

the grasses.

It was a conflict that would
set the world on fire.

The victor would force our ancient
ape ancestors out of the forests

and into the savanna.

And go on to trigger the birth
of human civilisation.

Subtitles by Red Bee Media Ltd

Email subtitling@bbc.co.uk