(gentle guitar music)
I 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.
(gentle guitar music)
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.
Just look at this seed.
It's small, it's brown,
it weighs hardly anything.
Looks pretty ordinary.
But actually, nothing could be further from the truth,
because what it will become
is truly extraordinary.
(uptempo music)
These are giant sequoias.
Some are over 3,000 years old.
And sequoias are the largest single life form on Earth.
All from a tiny seed.
Yet, even that pales into insignificance
when compared to what the whole
the plant kingdom's done
throughout the history of our planet.
It's a whole new story about our Earth,
told through remarkable images,
captured for the very first time,
and the latest scientific discoveries.
I love this. This is just fantastic.
(uptempo music)
This program is about just one type of plant,
the most underrated but perhaps the most important of all.
One that, by taking on and conquering
the rest of the plant kingdom,
shaped the face of the planet
and went on to help create human civilization.
This is the story of the rise of that underdog.
(uptempo music)
(gentle music)
For hundreds of millions of years,
throughout the time of the dinosaurs,
forests ruled the land.
(gentle music)
It was so warm, trees extended over most of the Earth.
Imagine the Arctic and Antarctic without ice,
carpeted with forests.
(gentle music)
Welcome to the planet of the trees.
(gentle music)
Today, isolated remnants of those
expansive forests still exist,
and here in East Africa is one of the most impressive.
The Kasagu cloud forest
rises out of the dry plains of Kenya.
(gentle music)
Cloaked in moisture, it's much the same as it was then.
Oh, at last. Look at that.
But millions of years ago,
a challenger to the old dominant trees
came on to the scene.
And the best way to find it is to climb right down,
into the depths of the forest.
There's never really elegantness.
This is when the adrenaline thrill starts to come in.
To be honest, I'm not quite sure after you get to,
there's a little lip.
Just seems to go straight down.
This is the oldest forest in Africa up here.
A relic, really, of the time when
trees dominated the planet.
So, this really has a feeling of descending
into that ancient lost world.
(slow tempo music)
Back then, trees ruled
because wood gave them the strength to grow ever taller
and to gorge on the sunlight all plants need.
As you descend, you get a real sense
of how trees bully and overshadow everything below.
We've come about 10 meters just into the canopy.
And (chuckles) I've nicked the cameraman's light meter
just to see what the light levels are doing.
And already, we've dropped by about a third.
Oh God, finally.
Now, let's see.
See how that light's doing.
That's gone down by a half.
These huge trees here have stolen half the light.
Down here, the trees are intimidating.
But it's not complete gloom.
Patches of sunlight do break through to the forest floor.
And those shafts of precious light
offer the chance for a new type of plant,
one that would come to take on the trees.
So, how did scientists
discover the identity of the challenger?
It's all thanks to a rather enchanting piece of research
involving what's inside this little box.
You'll never guess what it is.
This is a piece of fossilized dinosaur poo.
It stinks.
It's from a titanosaur sauropod
which is kind of like a brontosaurus,
my favorite dinosaur as a kid.
It weighed about 100 tons which makes me think
that this is just a fragment
of something the size of, I don't know really.
Something big anyway.
Scientists love fossil poo, coprolites, we call it
because they tell us about the diet of animals
and particularly in this case,
about the plants that were around
when dinosaurs were here.
And when scientists analyzed this one a few years ago,
they found it contained something really strange.
Under the microscope,
the scientists saw a fragment of a plant.
It had a distinctive pattern,
these figure of eight nodules.
They turned out to be the defining feature
of a family of plants they were astonished to see.
The grasses.
It was from 66 million years ago,
evidence for the earliest grass ever found called matleitis.
From its humble birth,
grass would eventually become
one of the most dominant forces on our planet.
(calm instrumental music)
But its rise would be a David and Goliath
battle with the trees.
You can still find descendants
of those early challengers today.
Plants like this.
And we think these are similar
to what the first grasses must have looked like.
You can just imagine them
struggling away on the forest floor,
just feeding off little scraps of light
making it through the canopy.
It's wonderful to think that dinosaurs
the size of houses were trampling through forests like this,
just grazing on little patches of grass.
But the dinosaurs' days of grazing
were about to end abruptly.
(slow tempo music)
65 million years ago,
an asteroid 10 kilometers across killed them off.
The grasses survived.
But in turn, they would face their own crisis.
What was coming had nothing to do
with the plants and animals that lived on Earth.
It was all to do with the atmosphere,
and that was changing for the most surprising of reasons.
Our air contains carbon dioxide.
It's the gas that plants need to breathe to stay alive.
But between 50 and 30 million years ago,
this gas began to disappear,
threatening all plants.
(intense orchestral music)
The crisis started with the creation
of huge mountain ranges like the Himalayas.
(rumbling)
The biggest period of mountain building in Earth's history.
(intense orchestral music)
The freshly exposed rock was washed away.
(rumbling)
Some of the minerals ended up in the sea.
(waves crashing)
And here they sucked the carbon dioxide gas out of the air
combining with it to form an entirely new type of rock.
(rock breaking)
Limestone.
I can show you that limestone's got carbon dioxide in it
because if i put a little bit of acid on it,
it should fizz like mad.
(acid fizzing)
What this is doing is it's liberating carbon dioxide
that had been in the ancient atmosphere
and has now for the last few million years
been locked away in this rock.
(slow tempo music)
By 30 million years ago,
as the mountains had risen,
the level of carbon dioxide fell.
In fact, carbon dioxide levels dropped to a sixth
of what they were beforehand,
which is an enormous fall,
and for the plant kingdom it meant crisis.
Without enough vital carbon dioxide,
many plants including the grasses
were struggling to survive.
(fizzing)
(slow tempo guitar music)
One way to reveal the impact this had on plants
is to look at a clever bit of human machinery.
The car engine.
Because what's under the bonnet
shares surprising similarities with plants.
(slow tempo music)
A car engine relies on two things to work.
It needs petrol and it needs oxygen from the air.
Inside the engine, these two are combined
to release the energy to power the car.
It's called combustion.
(engine buzzing)
Like the engine, plants also need
a gas from the air to work,
in their case, the carbon dioxide.
So for plants,
(engine buzzing)
the collapse of carbon dioxide levels
were similar to car engine starved of oxygen.
If I block the air intake,
you can feel the engine stuttering away
because it's struggling to get the oxygen
that it needs to work.
With less carbon dioxide in the atmosphere,
plants also began to stutter.
But the grasses were evolving
a new and ingenious invention.
Again, the engine provides a parallel.
But there's a piece of shiny machinery here
that any petrol-head will recognize.
What that does is the opposite of my hand.
It forces more oxygen into the engine.
It's called a turbocharger.
More oxygen means that
the petrol burns more fiercely
and that means more power.
Power enough to do this.
(car buzzes)
(laughs)
(howls)
(slow tempo music)
Evolution often comes up with our cleverest solutions
during desperate times.
And one group of plants, the grasses,
turned this crisis into an opportunity.
Grasses like this, this is elephant grass
which is one of the fastest-growing plants in the world.
In three months, right,
this stuff grows four meters.
That's that much every day.
This phenomenal growth rate was only possible
because of a technology that evolved 30 millions years ago.
A design so effective that if you're a mechanic,
you'd be blown away.
The new grasses came up with the equivalent
of a turbocharger inside the leaves.
It's in the cells of the leaves
that photosynthesis occurs,
where carbon dioxide is combined
with water to make sugar.
But the new grasses created an add-on,
rings of specialist cells known as bundles.
It all acts as a miniature pump,
sucking in and concentrating vital carbon dioxide.
So, although there was less carbon dioxide in the air,
the grasses had the edge over other plants.
(soothing piano music)
You know, when you study the planet,
you're so used to seeing the big events like
I don't know, ice sheets melting and volcanoes erupting.
But with the rise of turbocharge grasses
you've got something that's the tinniest of events.
It's something almost invisible
tucked away inside the leaf of a plant.
It's what makes the story of plants just so fascinating.
(lively orchestral music)
The grasses had found a way to survive the crisis.
(lively orchestral music)
But forests still ruled the world.
(lively orchestral music)
The huge trees had also survived.
Then the underdog unleashed a devastating new weapon.
Eight million years ago,
by now the climate had altered.
Much of the earth was dryer than ever before.
It was the moment grasses had been waiting for.
The grasses had evolved unique properties
that made them especially flammable.
When dry, they became like a tinderbox.
All they needed was the spark.
(thunder rumbling)
(intense orchestral music)
Today there's an ideal place to see
what happened eight million years ago.
Here in the national parks of South Africa,
rangers deliberately start huge fires to manage the land.
And for me, it's the perfect opportunity
to see how back then grasses exploited fire.
So, we're gonna get a chopper coming right down this lane
dropping incendiaries all the way along here.
(helicopter flying overhead)
Chief fire starter is Chris Austin.
Thanks for the treat.
He coordinates the helicopter crew
as they drop fire pellets onto the grass.
Artificial lightning strikes.
Now, what's gonna happen is they just sit there,
they just open up, ignite
and then you will just see them erupt.
(helicopter flying overhead)
Next 46 seconds which is
quite a long time. 46 seconds.
That's nice and precise.
There we go, there's one.
Come and have a look.
Yeah, there's probably another one there but.
13.
This should ignite now.
Behind this. Chris: It should go.
It should go.
There.
And then over here, we got ourselves another one.
So, this lane, this whole lane now
is just gonna go up into a wall of flames,
another one there.
Is it safe now here?
She's gonna go up slope, yeah?
She's gonna go away from us?
And of course, if the wind's pushing it it'll accelerate.
You can see that's now being pulled by the slope.
Oh, I can feel it.
It's burning my face already.
(fire crackling)
Look at that. That's amazing.
It's just a wall of smoke and flame.
Unbelievable.
(fire crackling)
The most aggressive fire that I've seen
moved at more than three meters a second which is--
Three meters a second, that's phenomenal.
It's really quick.
You can't outrun it.
The fires that kill people are grassland fires
because they're so fast-moving.
And that's not all.
Grass burns in a special way,
a way that was devastating to its enemies.
(giggles)
I've kind of fallen into it.
To discover more about its properties,
I've volunteered to enter into the heart of the fire.
This stuff that's going in now is not
kind of medical monitoring,
this is actually for monitoring the temperature of the fire.
It's a thermocouple wire that's gonna go
running down, in this case down my leg.
I think this is probably the first time
this has been done, really.
First time I've ever done this with a guy.
(laughs)
First time you put your hand down a man's trousers.
If you get stuck, that's us virtually married.
Once in the flames,
we hope to combine readings
from the heat sensors on my suit
with a thermal imaging camera
to reveal the secrets of a grass fire.
(fire crackling)
The fire is picking up speed.
(oxygen hissing)
I can't believe I'm seeing this.
It's starting to come towards us.
This just seems like one of the daftest things I've done.
(fire crackling)
Look at the flames!
Grass fires are very different from other fires.
The readings show that the hottest area of the fire,
the white parts on this image,
is not in the burning grass but a meter above it.
The temperature here is over 360 degrees.
(fire crackling)
Grass ignites more easily than other plants
and it's transformed into a volatile gas.
This gas rises and burns even hotter than the grass itself,
making it one of the fiercest
and fastest fires in nature.
(oxygen hissing)
(fire crackling)
(oxygen hisses)
Oh, I know this feels, sounds really strange but
it was actually quite a privilege to be in there.
You know, normally if you're stuck in one of them
you just don't come out.
It was great, at one point the flames comes up
and I just looked down,
and it was just lapping against the mask.
You kind of feel sorry for the trees.
(gentle piano music)
The next day, the fire still smolders.
It's so strange.
Why did grasses evolve
to encourage fires to take hold,
ripping through the landscape and destroying plant life?
It seems suicidal.
Grasses don't just encourage fires to start,
they're also designed to survive them.
In fact, they're the most fire-resistant plant on earth
and you can see here, this all looks scorched.
Look at it, it's still...
Look at the charcoal and smoke there.
But the thing is, if you just peel this back,
you quickly find that, look at that.
There's a lot of that that's still alive.
In fact, the trick really,
the solution to why grasses can survive
isn't on the surface, it's just below the surface.
If you open up these stalks,
you can see that right here there's a little bud.
It's stuck under a kind of insulated thick coating.
It's kind of tucked away in its underground bunker.
It's still alive.
So you look around here
and you just think everything's dead,
and that tree, that tree certainly is.
But the grass, the grass is just biding its time.
It's very much alive.
You know this scene, this could easily be a scene
from eight million years ago,
where the grasses just really quickly
recover and recolonize,
and the sneaky bit is they do it much faster than trees.
(gentle music)
(helicopter flying overhead)
In the wake of this onslaught,
the forest started breaking up.
The grasses were on a land grab,
conquering the territory once held by the trees.
The expanding grasses turned the Earth
into a flammable planet, a fireball world.
It must have seen about a million million trees burned
and black ash filled the sky
for hundreds of thousands of years.
And for the trees, this was apocalypse.
The world was ablaze.
The challenger had sparked a revolution
that was changing the face of the planet.
(intense orchestral music)
But the global rise of grasses
wasn't just reshaping plant life.
It was transforming the animal kingdom, too.
So, how do we know this?
(gentle instrumental music)
The effects of the spreading grasses
have been revealed by
one of the most elegant pieces of forensic science.
Part of the evidence had been discovered
here in North America
and it comes literally straight from the horse's mouth.
Come on.
(horse snorts) Whoa!
(gentle instrumental music)
When an animal eats a plant,
the carbon of the plant is absorbed into its teeth.
Studying the teeth tells you whether
the herbivore has eaten the leaves of trees
or the new grasses.
And the fossil teeth from millions of years ago
tell a remarkable story.
This is the result of the scientific analysis
of tooth enamel from herbivores in North America.
You can see down here this is us
going back in time in millions of years.
Now, the thing is, up to about
eight millions year to about here
you could see that herbivores are largely
eating shrubs and trees.
But then there's a really dramatic change about
between seven and six million years ago.
And after that, they're eating grasses.
And the thing is this sudden switchover
isn't confined to North America.
Here's a graph for South America
and here's a graph for Africa and also for Asia.
You put them together, look at that.
What these graphs tell is the same story
and that is in a period of about one million years,
a geological instant,
the world's herbivores dramatically change their diet
so that they're eating the new grasses.
This discovery proves that by six million years ago,
grasses were dominating the land.
It was a domination that would have
striking consequences for many animals.
(thunder rumbling)
And it's involved another piece of clever engineering
from the grasses.
This is it.
This is the stuff I've been looking for.
This is the sharp stuff, I'm pretty sure of it.
Let's have a little look.
Ah, you...
Oh, that's something we've all done in the past.
Cut ourselves on a blade of grass.
Look at that.
I'm bleeding.
But have you ever wondered why that happens?
It's actually all to do with something
that coats the edge of the leaf.
Grass extracts a mineral called silica from the soil.
This silica is built into row upon row
of tiny daggers along the leaf.
It's a defense to discourage animals from eating it.
Although tiny, these weapons
led to one of the biggest extinctions
of mammals in Earth's history.
The world had been full of many
different plant eaters,
including the vast Baluchitherium.
(snorting and grunting)
These 20-ton beasts were the largest
mammals ever to exist.
They fed off trees and shrubs
but as their food source disappeared,
these animals died out.
(snorting)
In North America alone,
grasses led to the extinction of over half
of all plant-eating mammals.
But some herbivores thrived.
It's all down to the teeth again.
Who would have thought that
gnashers could be so important?
You could see how the survivors coped
with this skull here.
They developed harder teeth
to bite through that silica-edged grass
and also longer grinding teeth
to that it didn't matter if they get worn down.
The creatures adapted
and this is one of the results.
The jaw of a modern-day horse, like Tank here.
By six million years ago,
the triumph of grasses had caused the death
of many types of animals,
while creating vast herds of new ones,
the more familiar plant eaters we know today.
(intense orchestral music)
But that's just the start
because if you've got herbivores
consuming silica-rich grasses,
all that mineral has to go somewhere.
As manure.
The herds of herbivores were producing
millions of tons of manure everyday.
It's washed away into rivers
until finally it reached the ocean.
And within it was all that silica.
It's out in the oceans that
things really began to take off
because it's out here that there's creatures
that are addicted to this silica.
These creatures are microscopic.
A few hundredths of a millimeter across.
They're diatoms, a type of green algae.
Diatoms are wonderfully delicate,
like some kind of alien architecture.
But essentially for the construction
of their tiny skeletons is silica.
Five million years ago,
they were feasting on huge amounts
of silica from the grasses.
For the diatoms, it was like Christmas.
Their numbers exploded.
(uptempo music)
And diatoms are crucial because they form
the foundation of the ocean's food chain.
With more diatoms came huge shoals
of anchovies and herring that eat them.
This in turn attracts predators like seabirds and dolphins
and even bigger hunters.
But it's from space you really appreciate their importance.
They appear as vast green blooms.
When they bloom, they cover over a tenth of the oceans.
They're green because like plants
diatoms contain chlorophyll,
and like plants, they all release oxygen.
(squawking)
Those photosynthesizing diatoms
produce about a quarter of the oxygen in the atmosphere.
So if you like, every fourth breath you take on average
has been exhaled by the diatoms.
They really are the lungs of the ocean.
It's remarkable what the humble grasses had achieved
by five million years ago.
A once-forested planet was now dominated by open plains.
(uptempo music)
8,000 different species of grasses
covering a quarter of all land.
They'd selected which animals would live or die.
(uptempo music)
And they'd fundamentally altered the oceans
playing a crucial role
in the make-up of our atmosphere.
Yet, perhaps the most important impact
of this remarkable plant was still to come.
The impact on our story.
(vehicle buzzing)
Human beings.
(gentle music)
And that's why I've come to the savanna of West Africa.
I'm in Senegal to see a scientific first.
It's a discovery that's got profound implications
for our understanding of our own past,
because it's here in Africa
that our earliest ape ancestors emerged.
Five million years ago,
why did one group of apes leave the trees for the savanna
and develop so differently eventually becoming human?
Well, the chimpanzees here might provide some answers.
Because unlike almost all other chimps in Africa,
the ones here in Fongoli live on grasslands.
Jill!
Hey!
Welcome.
I'm Iain.
It's what makes them so fascinating
to anthropologist Jill Pruetz.
This is HQ, chimp HQ. Jill: Yeah.
This is home base.
Everyday we take off wherever they're at.
Jill has spent 10 years studying the Fongoli chimps
She's most interested in parallels
between the unusual behaviors of these chimps
and what might have happened
during the evolution of human beings.
Settled around the waterhole like that.
(chimps screeching)
I wasn't expecting that.
I guess I was expecting them kind of
swinging through the trees, but look at them,
they're just ambling along on all fours.
Perfectly happy down here on the ground
walking through the grass.
And they look so human.
I know, it's obvious, really obvious thing to say
but they just look so human.
The Fongoli chimps have other human attributes.
They are proficient at using tools
like sticks for collecting termites.
Many chimps in Africa catch termites this way,
although these chimps do it more than any others.
But what makes them really special
is a hunting technique, one that is unique.
I think that probably the most exciting discovery made
was that they hunt with tools,
which before we had thought only humans did.
How is that?
They'll fashion branches into sort of like a spear
and they'll use it to jab into these tree holes
where you have another kind of primate, a bush baby.
And then they jab it into the hole.
Jill's filmed this remarkable behavior,
the first time it's ever been recorded.
It shows a chimp using a spear he's made
to stab and kill a mammal, a bush baby.
Yeah, that was something that
again, we sort of had used that to define humans.
Really? Jill: Yeah.
So that's starting to blur the boundary.
Yeah.
(chimps screeching)
The chimps of Fongoli are the only ones
in the world that have been observed
using spears to hunt mammals.
(chimps screeching)
Jill believes they've had to come up with this behavior
to cope with the harsh and dry grasslands.
It's a more hostile habitat than the forest
so the chimps here have to be smarter.
And Jill has discovered a final
extraordinary behavior of these chimps.
It also reveals more about how
our ancient ancestors might have evolved
as they moved out of the forests.
This is a nice one I think from the wet season.
So, this is a grassland.
I can see a group of them in there.
Yeah, about three, four of them.
You can see them just above the grass but watch.
Watch what they'll need to do here.
(laughs)
One of them just stood up.
Yeah.
I mean, he obviously has to do that to see over the grass.
I want to see that again, yeah, let me see that.
(gentle instrumental music)
Many scientists think this is perhaps a mirror
of what happened as our own forebears
stood up on the grasslands for the first time.
It allowed them to keep an eye out for predators and prey.
And eventually to evolve walking.
That's incredible to see chimps in the wild standing proud
in the savanna grassland. Yeah, yeah.
And looking incredibly comfortable as well.
It's exciting to see it.
It's the grasslands that's kind of
driving and encouraging them
to develop that way. Yeah, yeah.
What, to be more resourceful, more resilient?
I think so.
They have to be creative and resilient.
I've just got this weird feeling
that I'm looking at a bit of video
from four, five million years ago.
Do you know what I mean?
That could be the scene. Mm-hmm.
Here at Fongoli you can actually see
what scientists think happened when
grasses shaped our ancient ancestors,
and encouraged them to make those first
upright steps onto the savanna.
And it really brings home how our human journey
began on the grasslands.
(gentle instrumental music)
Over the next five million years,
these ape men continued to evolve in Africa.
Until eventually they became homo sapiens.
And then 100,000 years ago, these new people,
for there really were people now, like you and me,
began to migrate across the rest of the world.
At this point in time,
our ancestors were hunter-gatherers.
They were living a tough life in small family groups,
killing wild animals
and collecting berries and roots to eat.
But grasses hadn't finished with us
because they trigger the greatest revolution
in humankind's existence.
(calm instrumental music)
It's not in Africa but here in Southern Turkey
that archaeologists believe
they have discovered why that revolution happened.
The place is called Gobekli Tepe.
For me, this is one of the most
exciting sites of modern archeology
because here at Gobekli Tepe
are some of the oldest buildings in the world.
They date to nearly three times the age
of the first Egyptian pyramids.
And there's a real mystery here.
Who built this place?
And more importantly, how could they have done it?
(slow tempo music)
This astonishing structure is 12,000 years old.
It lay buried and undiscovered until 1994.
Hello.
Hello Iain.
The archaeologist who unearthed it
is Klaus Schmidt.
Well, it's great to be here.
Hi. Welcome in enclosure C.
(laughs) Enclosure C.
What a place! It's spectacular, isn't it?
I mean, these are great.
Big question is who are they?
One thing is very important.
Never a face is depicted,
they are always faceless.
I saw you as you came down,
you were working on a very sophisticated
one here. Yeah, yeah.
This looks amazing, what is it?
It is a masterpiece of craftsmanship.
It's one stone, it's one made from one stone.
We have a flat relief of a boar
and we have this high relief of a leopard.
This is an extremely complex society.
Yes, yes and this is a surprise.
We didn't know this, we didn't expect this.
What we are doing here,
we're at a chapter in world history,
a chapter which we didn't know it exist before.
To construct Gobekli Tepe with its 50-ton megaliths
would have needed a huge army
of well-organized workers.
Yet, 12,000 years ago was the Stone Age,
a time when people were supposed to be
hunter-gatherers living in small groups.
How did they sustain the numbers
essential to build such a vast temple?
The answer lies a short distance away.
(slow tempo music)
Within sights of Gobekli Tepe
are the Karacadag Mountains.
Here something happened at this time
that would change our world forever.
It was all to do with one particular type of grass.
It's an ancient type of wheat
which grew totally wild, just as it does today.
it's called einkorn wheat.
12,000 years ago was a time before farming.
The people here would have been desperate
for whatever nutrition they could gather.
Yet collecting it presented a huge problem.
Let me show you why.
When the head of the wheat is ripe
then just the tinniest of touches and look what happens.
It just scatters everywhere.
And that's because the seed is
attached to the plant so precariously.
Imagine if you were trying to collect
enough seed for a meal.
I mean, I can hardly even see where they are.
Here's one. Ah, dropped it.
It would drive you mad.
Frankly, it's hard to believe anyone would bother.
But everything was about to change,
triggered by a crucial event.
A tiny alteration in the genetic makeup
of a wild wheat plant.
Just one gene in just one single plant.
That mutation has been traced back to here,
just 30 kilometers from Gobekli Tepe.
If you look closely, you can see the difference
between the two types of wheat.
In the original wild wheat, a special ridge of cells
between the stalk and the seed
breaks down as the plant ripens,
and this allows the seed to fall away.
But in the wheat with the genetic mutation,
these cells remain as a solid band.
It means the new wheat never lets go of its seeds.
Under normal circumstances in the wild
that would doom the plant
because it just couldn't scatter the seeds.
Look, you bang it and nothing happens.
But it turns out that for one animal species
this trait was really beneficial.
Us.
(gentle music)
Because the seed remained on the stalk after it ripened,
it meant that not only could the people who lived here
collect more grain, they could also begin to farm it.
In other words, they can take
some of the spare seeds at the end of a season,
put it back in the ground
and then harvest the new plants the following year.
It was the dawn of domesticated wheat.
(wheat rustling)
And this wheat gave us bread.
A fabulously concentrated form of energy.
It could be carried,
it could be divided up, it could be stored.
And in turn, bread would lead to something even bigger.
(slow tempo music)
In order to build Gobekli Tepe,
the Stone Age people turned their back on hunter-gathering.
They became the first farmers.
12,000 years ago, they began
to sustain themselves with bread
made from the grass we call wheat.
Now they could feed the huge workforce
required to construct such a vast
and sophisticated temple.
The mystery of Gobekli Tepe was solved.
People had been hunter-gatherers
and now this site marks the end of that time,
the end of the period and the beginning of a new age.
So Gobekli Tepe is part of that chain reaction?
It's a cultural--
The people being in Gobekli Tepe
are the first people having bread also in the villages,
not only here but also in the villages.
That's incredible, isn't it?
To think that these were the first people
that's gonna taste bread Yeah.
And it was (mumbles). Klaus: Yeah, for sure.
And the idea then that it was bread
that was the kind of energy source essentially,
the sustenance.
Exactly, exactly.
It's a turning point in world history.
(lighthearted piano music)
There's one last thing that I find intriguing.
Our ancestors must have felt
that they were the masters of this new crop,
in the same way that we still feel today.
But in farming we are in control of the plants
that we grow and harvest.
But think of it for a minute from the wheat's point of view.
I mean, here's a plant that's done something really clever.
It's attracted an animal that's prepared
to sow it, to nurture it,
to protect it from competitors and scavengers.
It's also prepared to disperse its seed by hand
without the plant having to do a single thing.
So, it begs the question, who's using who?
(lighthearted music)
Human beings had now invented
a way of harnessing the power of plants,
and once invented, it could never be reversed.
Because farming allowed us to come together
in bigger and bigger groups,
to build villages, towns and eventually cities.
(lighthearted music)
A world once dominated by forests and dinosaurs
had given way to a world of our own making.
(lighthearted music)
I've always been fascinated by how our planet
changes over time,
over the 4 1/2 billion years of Earth history.
And what's astounding is how important plants have been
in changing that original lifeless rock
into this vital and vibrant world that we live in today.
Our home.
Over this series, we've seen how plants
gave us the oxygen in the atmosphere.
We've watched as the rise of flowers
painted a drab world with brilliant color.
And we've discovered how plants
shape the animal kingdom.
And for us, the humble grasses
play the most important role of all.
They drove the rise of our ape-like ancestors
and ultimately, triggered the birth of civilization.
Plants made us and the world we live in.
(lighthearted music)