Original subtitles

(dramatic music)

Earth is born out of chaos and catastrophe.

(object banging)

Despite such hostile conditions,

life emerges on our planet.

(water flowing)

but it must withstand deadly disasters again and again.

(wind whooshing)

Planet Earth is a wild world

shaken by unimaginable impacts,

volcanic eruptions that flood the landscape

and drastic climate changes that lead to ice ages

that freeze the world from pole to pole.

Yet each assault creates a path for something new.

(birds chirping)

Life always finds a way

despite being constantly put to the test.

Without these catastrophes, life as we know it

would not exist on our fateful planet.

Life evolved on earth four billion years ago

when a series of severe ice ages froze our planet.

They almost destroyed everything alive,

but when the last glaciation ended,

earth became a giant greenhouse.

Oceans turned tropical

and made way for an unprecedented explosion of life.

This profound change marked the beginning

of the Paleozoic era 541 million years ago.

(water splashing)

Life experienced significant evolutionary developments

and took on much larger dimensions,

thriving in new forms and conquering new habitats.

But during this era, which lasted close

to 300 million years, the planet was stuck

by deadly catastrophes.

The last and worst was a mass extinction

that wiped out almost all life on earth.

(animal growling)

Scientists around the world are investigating

how life in the Paleozoic evolved

and which events ultimately resulted in the disaster

known as the Great Dying.

Morocco, in this dry, dusty north African landscape

there is fossilized evidence of the biological revolution

that became known as the Cambrian explosion.

Paleontologist Philipe Havlik is here to find out more

about how that complex life evolved.

The story unfolded underwater

and what was once a vast ocean.

The Cambrian explosion being the beginning

of the Cambrian period is the most exciting thing

for any evolutionary researcher.

It was the moment when almost all invertebrate animal groups

suddenly appeared overnight, as if out of nowhere

they started to divide into all kinds of species.

We found hundreds of species

within a very short period of time.

We still require an enormous amount of research on this

and still don't know exactly what happened.

Philipe has arranged

to meet with a local fossil trader

who will help him decipher the story.

Like many people in the area,

Mohan Imati has traded in fossils his entire life.

We can look at this layer.

Maybe first some on the rocks, huh?

Soon the experts find something interesting.

What do you think about this one?

Yeah, yeah, that is good fossil, it's trilobyte.

It's almost complete, huh?

Yes, it's complete, yeah.

Trilobites

are kind of like cockroaches among fossils.

Their body is divided into three parts.

We have the head, the cephalon, the thorax,

the body, and the pyridium.

Basically, the rear end of the Trilobites.

Trilobites emerged

at the beginning of the Cambrian.

These arthropods are one of the earliest

and most diverse groups of multicellular organisms on earth.

(water flowing)

Along with their unique body shape,

Trilobites had a hard exoskeleton made of chitin.

This protected their soft bodies

and allowed their fossils to be well preserved.

While Trilobites were a huge part of the marine ecosystem,

they weren't the apex predators at the time.

(water flowing)

A terrifying giant shrimp like creature

known as Anomalocaris claimed that honor.

Anomalocaris was the fighting machine

of the Cambria, four feet long

equipped with long eye stalks,

giving it 360 degree vision.

It had large grappling arms at the very front.

Anything that came close to it was eaten.

(speaking in foreign language)

(gentle music)

(water flowing)

Philipe sees the Cambrian

as more of a revolution than an explosion

because it marked the beginning of competition

among living things.

Some developed a shell

and others developed weapons to crack this shell,

and so it came to an extreme arms race.

One had stronger tools.

The next had spikes and used them to fight back,

and in the end, the sea creatures we know today emerged.

Life exploded in the oceans.

Rising oxygen levels, genetic inventions

and environmental changes created a complex cocktail

that led to new and abundant diversity.

Within just a few million years,

mats of microbes covering the sea floor

evolved into complex life.

Simple unicellular organisms were replaced

by highly mobile creatures

that sported advanced anatomical features

like legs and eyes.

The Cambrian lasted until 485 million years ago.

It was followed by the Ordovician,

a second period of the Paleozoic,

where life continued to diversify through the emergence

of new marine species and ecosystems.

Organisms that were dominant in the Cambrian

were now replaced by a wide range

of new marine invertebrates.

The Moroccan rocks have an exquisitely preserved

record of the Ordovician.

Mohan takes Philipe to a site

where he recently found a Cephalopod,

a squid like creature

that was even larger than Anomalocaris.

That's what we found.

Oh, whoa, whoa, whoa, whoa, whoa.

It's actually a pretty nice piece.

And do you know the biggest of this one?

They reached up to nine meters

and just to shell its Camarasaurus, it was found in Russia.

Camarasaurus was the largest predator

in the Ordovician.

10 tentacles projected from its cone like body,

allowing it to catch and feed

on Trilobites and other creatures.

(water whooshing)

(dramatic music)

The tentacles grabbed the prey,

then sucked it inwards to be devoured.

This massive increase in size

is attributed to the evolutionary pressures

that develop in predator, prey dynamics.

Being big can help creatures avoid predators

or become more effective predators themselves.

Scientists believe the environment

also affected this growth.

In the Ordovician,

the first plants emerged on land,

which increased the oxygen levels

and thereby led to climate fluctuations.

This, of course, is a trigger

that significantly advances evolution.

Life must deal with new situations time and time again.

(gentle music)

The Moroccan fossil record

reveals a bustling Ordovician world

full of increasingly complex creatures.

But about 444 million years ago,

things suddenly changed.

The fossils show that there was a massive die off.

Even with their new adaptations, more than 85%

of marine life was wiped out.

(vehicle whirring)

Philipe is searching for clues about what happened

on the northern edge of the Sahara desert.

Here we have a seabed

in which numerous different fossils are preserved.

They indicate that we are exactly

at the right point in time.

(object banging)

But then he finds something unusual.

Here I have a stone within a stone,

and that shouldn't happen in this marine deposit.

We are relatively far out at sea here,

so there simply shouldn't be any pebbles,

especially not angular ones.

There's only one way to get them so far into the sea.

A small iceberg must have drifted out here.

(gentle music)

When glaciers move over land, they grind rocks

beneath them, picking up and transporting bits

and pieces until the ice melts.

Havlik believes that when an iceberg melted

in the Ordovician ocean, it dropped this pedal here

about 444 million years ago.

A glaciation event seems to be the only explanation

for the pebble trapped in older stone.

We also find such evidence in other places

around the world, not only in North Africa,

it's also in South America.

It's the same in Southern Europe.

It's something that appears everywhere.

That means the moment there is large scale cooling,

most creatures, at that time only sea creatures,

have no chance of survival.

In other words, most of them simply go extinct.

Complex life was flourishing

until suddenly everything changed.

Because the glacial deposits occurred at the same time

as the mass extinction event,

it seems plausible that an ice age was responsible

for the death of so many new species.

But how did the climate suddenly change

from tropical to Arctic?

Iceland, to uncover what could have caused

such a huge glacial event,

geologist Professor Colin Devey has come to a unique place.

We're in the Silfra gap,

and this is where you can really see

plate tectonics in action.

You can really see one side

of the earth moving away from the other side of the earth.

This is where tectonics really happens.

Rocks here reveal how earth

is shaped by internal forces

deep below its crust, the thin outer shell of our planet.

Collin believes these forces played a crucial role

in the extinction event at the end of the Ordovician.

Iceland is a place on the planet

where you can see wet tectonic plates, where the surface

of the earth actually splits apart.

Tectonic plates provide clues

about what's happening beneath the surface of earth.

Today we have seven major plates and numerous smaller ones.

They all rest on the molten rock of earth's mantle

and fit closely together.

The tectonic plates move due to heat

from radioactive processes inside earth.

At times, they move closer together

and at others, farther apart.

(dramatic music)

This is the edge of a plate.

This continental drift is what this is all about.

This is the result of Europe going that way

and America going that way, not very fast.

It's about as fast as your fingernail grows.

The gap is part of the Mid-Atlantic ridge

between the North American and the Eurasian tectonic plates.

Okay, that was the easiest

transatlantic flight I've ever done

and the quickest, probably not the warmest,

but hey, you can't have everything.

When the plates move apart from each other,

the land between them suffers enormous tension.

A major earthquake eventually rips through the rock

to release pressure, creating enormous fissures

like the Silfra gap.

What's happening here normally happens on the sea floor

at about 2,500 meters depth,

in the Atlantic, even deeper, 4,000, 5,000 meters.

This is how the earth has changed its face,

has changed life on earth,

has changed everything about the earth.

Since they first formed,

the tectonic plates have continued

to move around the planet.

Over time, the continents they create also change.

About 444 million years ago,

our world looked very different, which could be important

to the Ordovician mass extinction

Plate tectonics is the thing that drives the puzzle.

It moves the continents around.

At the end of the Ordovician,

plate tectonics had pushed the continents together

into a big lump,

into a big mass of continent called Gondwana.

Gondwana was a super continent

covering almost 1/3 of the earth's surface.

The giant landmass almost stretched from the equator

to the south pole,

and included the modern continents of South America, Africa,

most of Antarctica and Australia and some of India.

And life in the Ordovician

was mainly on the shelves around the Gondwanan continent.

Gondwana had moved quite a long way down south,

so it was at the South Pole,

or part of it was at the South Pole,

and that seems to have set the world up

for very bad environmental conditions

for life in the oceans.

(dramatic music)

Life thrived on the super continent.

Sea animals like Conodonts and Trilobites flourished.

But as the continent began

to move farther towards the South Pole,

it had a catastrophic effect on living things.

And if the ice builds up, sea level drops,

then those shallow water regions

around the continent are all of a sudden dry land

and there's no place to live.

And it seems like that is probably one of the pressures

that really hurt life in the Ordovician earth.

Major glaciation at the end

of the Ordovician caused sea levels to drop.

The consequences were dire.

85% of marine species were wiped out.

It was a colossal loss of life.

(water whirring)

The Ordovician mass extinction led to the Silurian period

that began 443 million years ago.

It is characterized by the recovery

and triumphant reemergence of life

after just a few million years,

creatures were rapidly evolving

and becoming even more complex.

They exploited new habitats, found new sources of food,

and moved in new ways.

The Silurian ended 419 million years ago

and gave rise to the Devonian period.

Back in Morocco,

Philipe Havlik has rejoined fossil trader, Mohan Imati

to investigate how life evolved

in this important chapter in Earth's history.

The Devonian is also well preserved in Moroccan rocks.

Over the years, Mohan has collected many fossils

from this period, especially Trilobites.

It is my Devonian stuff I collect long time ago.

(person laughing)

So this is 20 years of collecting or how much?

More, yes.

The Trilobites in the Devonian in particular,

show an incredible diversity.

There are some that have huge eyes

with many complex facets on them.

They can basically see everything.

Some even have appendages on their heads

so that they can swim through open water.

There is really everything you can imagine,

a biodiversity that we have never seen before,

and probably the greatest variety of trilobite species ever.

But other animal groups also evolved rapidly

during the Devonian to become more dominant.

You could call it the age of the fish.

These had an exoskeleton that consisted of a certain number

of plates, and so did the chewing tools.

Dunkleosteus

was one of the largest of these armored fish.

It was a colossal sea creature

that may have reached 26 feet in length

while ruling the oceans

and devouring everything in its path.

Dunkleosteus had a huge pair

of crushing shears at the front,

which it could consistently resharpen.

They simply crushed on top of each other.

It cut through everything that got in its way.

(water whooshing)

As the oceans grew busier during the Devonian,

some creatures began looking

for alternative, less crowded environments.

A fish known as Tiktaalik

attempted a revolutionary strategy.

It tried to transition out of the water, onto land.

For a vertebrate, life in the water

cannot be compared with life on land.

If you make a swimming movement,

you can have wobbly fins,

but on land, it's a completely different situation.

You need a rigid frame so that you can move around.

That's exactly what Tiktaalik had.

It had fingers, it had arm bones.

It had an internal skeleton, a spine that allowed it

to use its four legs to move around perfectly.

(speaking in foreign language)

Tiktaalik was challenged

to develop the ability to breathe air,

but was successful becoming the first vertebra

to conquer land.

But just as animals

and plants were gaining a foothold on land,

a new threat emerged once again.

(tense music)

Effenberg, Germany.

Geology professor David De Vleeschouwer

and a team of students are searching a quarry

for clues about the fateful events

that took shape at the end of the Devonian.

(gentle music)

This is the wall that we're going to sample,

today, as you can see,

there are two very pronounced black shale layers

that you can readily see.

So when we find a black shale like this one

in the geological record, it's a clear indication

that we had low oxygen

or even no oxygen condition in the sea water.

And of course, that means that all the life

that was living in the water column had a difficult time

because all Devonian life,

late Devonian life in the water column

was dependent on oxygen.

(gentle music)

David and his team must collect rock samples

to understand how the Devonian climate changed over time.

They are time capsules of an ancient apocalypse.

(gentle music)

Back at the University of Münster in Germany, David

and PhD student Nina Visan use a special x-ray device

that allows them to analyze the rocks

and draw conclusions about the prehistoric climate.

So the sample we just analyzed came from a rock layer

just below the black shale level.

And what we've seen is very sharp transitions

between humid phases and arid phases.

So climate change was certainly going on

and playing its role in the dynamics

just prior to the anoxic event.

(gentle music)

David suspects

that the alternating phases of wet and dry climates

and the black layers of death follow a certain pattern,

a rhythm that can be linked to a cosmic event.

By the 17th century, scientists already realized

that earth doesn't follow

a perfectly stable orbit around the sun.

And Serbian mathematician Milutin Milanković

later calculated how the Earth's astronomical position

relative to the sun changes over time,

including the shape of its orbit.

That's what we call eccentricity,

and it's changing from a perfect circle

towards a more elliptical form

every 100,000 and every 400,000 years.

This leads to fluctuations

in how the sun's energy gets distributed on the planet,

which in turn triggers climate changes.

In addition, the elliptical orbit

coincided with an evolutionary development.

During the late Devonian vegetation on land flourished,

and some trees grew to heights of more than 100 feet.

Over time, ancient forest became established,

transforming land

that was once barren into a lush landscape.

Our planet gradually emerged as the familiar green

and blue earth we recognize today.

So during the Devonian, land plants really evolved widely

and developed deep root systems.

And that is important

because deep roots, they create a lot of area

where weathering and erosion can take place,

and a lot of weathering and erosion,

that means that a lot of nutrients

and detrital material can be transported, for example,

by rivers from the continent towards the ocean,

towards the seas.

(tense music)

At the same time,

Earth's orbit was becoming more elliptical,

which led to climate chaos.

The combination triggered a catastrophic chain of events.

And that is what we think is going on.

An enhanced hydrological cycle, much stronger monsoons

during those high eccentricity orbits,

bringing those extreme precipitation events

and flushing those nutrients towards the ocean,

they're acting as food for everything

that was alive in the water column.

When that life decomposed, when it was sinking

to the sea floor, it was consuming oxygen.

Thereby the oxygen levels in the oceans

were going down and suffocating life in the oceans.

Ironically, it was the evolution

of life on land

that was responsible for the demise of life in the oceans.

The astronomically forced climate change acted as a trigger,

pushing the system past a tipping point and into chaos.

Every animal in the intricate food web felt the impact

as four extinction events took their toll.

Ultimately, between 70

and 80% of all Devonian species vanished.

(gentle music)

Yet life was not to be defeated.

Despite the devastating mass extinctions

during the Devonian, these catastrophic events

paved the way for new species to emerge.

It was the start of an evolutionary pathway

that would one day forge the beginning of our own species.

A pathway Philipe Havlik

is especially interested in exploring.

Around 360 million years ago

in the Carboniferous period,

life had really arrived on land.

There were extensive swamp forests

and everything was lush and green.

And in the undergrowth, there was a lot of life,

including huge insects.

One of the most impressive

is this little dragonfly I am holding here.

Meganeura, an animal that had a wingspan of 20 inches,

so it was at least five times the size of today's dragonfly.

They really got big.

But while insects became supersized

and amphibians ruled the ancient swamps, a new group

of animals would make the most important evolutionary jump

during this era.

In the Carboniferous period,

vertebrates had already conquered

the entire coastal areas of the continent.

However, a very important step was still missing

in order to venture deeper onto land.

(speaking in foreign language)

Reptiles would make this leap.

For the first time in the history of life,

creatures would be able to fully live away from water.

But how?

The solution was as ingenious as it was simple,

the vertebrates simply took the ocean with them.

They packed it into a small bowl,

and were able to put it down anywhere on the continent.

We still recognize the shell and the small ocean today,

it is the egg, the amniotic egg.

(gentle music)

(object banging)

A key property of reptile eggs

is an amniotic membrane.

It's a protective envelope

that surrounds the growing life from external influences.

But another substance inside the egg

is also critical to this evolutionary step.

(speaking in foreign language)

What's inside the egg is the ocean,

what we call egg white.

This transparent liquid enables the developing life

to swim around in a small sea.

Not only does this ocean contain the embryo,

which is somewhere in the slippery stuff here,

it also contains huge food storage.

The egg yolk must be enough to feed the little one

until it is big enough to go ashore, survive on its own,

crack the shell, and start its own life.

(speaking in foreign language)

This key innovation

represented a major transition in evolution,

and because of it, reptiles were ready to conquer land.

The continents aligned to form a new super continent

known as Pangaea at the end of the Carboniferous period.

(tense music)

This heralded the beginning of the Permian

299 million years ago,

and would be the final chapter in the Paleozoic era.

South Africa,

the Karoo Basin is one of the best places in the world

to search for remnants of the Permian Period.

Paleontologist Professor Roger Smith

is trying to piece together

the evolution of terrestrial ecosystems

by searching for fossils that illustrate changes.

This level is at about 253 million years ago,

you would've been standing on a vast flat,

featureless alluvial plane,

but way off in the distance

you would've seen a mountain range.

The Gondwanan mountains.

The mountains were formed when the continent

of Gondwana came together.

Huge peaks were pushed up

as the continental plates converged

into a gigantic landmass.

Millions of years later,

when Gondwana began to break up into smaller continents,

it created a huge rift valley.

The rift widened and deepened over time,

filling with sediments washed down

from the surrounding mountains.

What is left today is known as the Karoo Basin.

In the late 1960s, near the town of Fraserburgh,

an incredible fossil site was discovered by accident.

It reveals a rare peak into the ancient past here.

This is really an amazing paleo surface.

It's a part of the ancient floodplain

that has been captured and frozen in time.

It's like a paleo Polaroid

of the middle Permian period showing us everything

that was happening on those ancient Karoo floodplains.

Look at these ripples, they are just as fresh

and as sharp as if they were made just the other day.

And there's the other right hand there.

So it would've been a movement like this,

rotate this, rotate this,

rotate this.

(gentle music)

The footprints may have been left by,

an herbivore that weighed as much as two tons

and reached 15 feet in length.

This species belongs to the Therapsids, a group of animals

that represents a crucial step in the evolution of mammals.

While not fully erect, Therapsids already had

a more upright posture and other mammal like features.

There was an abundance

of food in this area 260 million years ago

and life thrived in the warm climate.

Vegetation along the river banks

fed the fast herds of grazing herbivores,

which were dominated by moscops,

but there were carnivorous Therapsids too.

Towards the end of the Permian, a new type

of predatory evolved, the gorgonopsians.

They were large beasts with powerful jaws

and distinct saber like teeth.

The masses of herbivores were the perfect prey for them.

This is a gorgonopsian.

It's is a carnivore, clearly

because of its sharp saber like tusk or canine.

And these intermission sharp incisors.

With predatory carnivores

and a vast array of potential prey,

a dynamic and diverse food chain thrived here

for millions of years.

(animal growling)

But the Karoo Basin also reveals that something changed

around 252 million years ago.

A dramatic shift that can clearly be seen in the rocks.

(gentle music)

We're now up at this dramatic color change,

which I could see from a distance.

And you can now see that this blue, gray,

wet floodplain mud rocks here

have rapidly transitioned, rapidly at this point here

into something very red, very semi arid if you like.

And the most likely cause of that drying out

is climate change, rapid climate change,

and the effect that that rapid climate change had

on the environment and then on the animals

and plants is quite dramatic.

We can see that it's abrupt.

It's very fast, and it could be as little as 10,000 years

or up to 100,000 years,

but it's in that timeframe.

The change in color

not only marks a change in climate,

it also marks a change in the amount of fossils.

It's simple, below this line, there are abundant fossils

and above it, almost none.

This only mean one thing.

The change in climate led to a mass extinction.

The effect of that rapid climate change

on the animals and plants was dramatic.

So dramatic that 95%

of species worldwide went extinct.

The worst mass extinction that has been recorded on earth.

The once lush Permian environment

suddenly dried up.

Something drastic happened that caused the extinction

of most species on our planet.

An event that became known as the Great Dying.

(animal growling)

(tense music)

Iceland, the land of fire and ice

offers scientists a firsthand glimpse

of the tremendous forces our planet can unleash.

In the barren landscape of Laki,

geologist Colin Devey hopes to uncover remnants

of a historic volcanic event.

The great dying at the end of the Permian

coincided with a huge volcanic eruption.

And to get an idea of what might have happened then,

I've come here to Laki on Iceland, where in 1783,

a massive eruption covered the land here

with lava affecting the local population,

but actually affecting half the globe.

That's Mount Laki.

And I'm gonna go to the top

so I can get an overview of what this looks like.

(gentle music)

The event was called a fissure eruption.

It occurs when an elongated linear crack

opens on the earth's surface, which allows magma

to rise and erupt.

Look at that, it's amazing.

It's a row of volcanoes.

They disappear into the horizon.

I mean, that's got to be 20, 30 kilometers long.

The whole countrysides just covered in lava.

I presume the lava's come out of these volcanoes.

The eruption lasted eight months

and is thought to be one

of the largest volcanic events ever recorded.

I'm standing here right on the crack.

This is where the magma came out.

When the eruption was taking place,

you couldn't be anywhere in here

'cause it's all full of magma.

This was a magma channel.

This one obviously produced a lot of magma, a lot of lava

that got out of this crack

and covered the landscape around

what we saw from the top of the volcano.

The amount of lava produced

by the Laki fissure volcano in 1783 over the course

of eight months is staggering.

It produced 14 cubic kilometers of magma,

which is impossible to imagine.

But if you were to actually spread that out over the whole

of the USA, you'd have about like the icing on a cake,

1.4 millimeters of lava over the whole USA.

It's a lot.

But it's nothing

compared to what took place at the end of the Permian.

(fire whirring)

252 million years ago,

a massive volcanic event created one

of the most extensive volcanic landscapes in the world,

known as the Siberian Traps.

This is minuscule compared to the Siberian Traps.

This was 14 cubic kilometers.

The Siberian Traps were four million cubic kilometers.

So if you were to spread

the Siberian Traps all over the USA,

you'd not have 1.4 millimeters like you have with Laki.

You'd have 400 meters of lava.

It's a different beast altogether.

(gentle music)

Colin is looking closely

at data from the Laki eruption

to better understand the monumental impact

of the ancient eruption.

I found it really interesting,

but also very important document

on what happened here at Laki.

Normally, we geologists

get to situations like this after the event.

We can look at the rocks when everything's happened

and try and find out what happened.

But here, the pastor in a church 50 kilometers away

from here, so near enough to be influenced

by the eruption, wrote down what happened.

He describes how the lava advances down the valley

towards his church, towards his congregation,

destroying farms, destroying people's livelihoods

and actually killing those people

'cause they just died of hunger.

They died of starvation.

(fire whirring)

In the summer of 1783, the Earth shook

with fury when Mount Laki erupted in Iceland,

a 15 mile long fissure tore open,

spewing molten lava into the air.

Villages were engulfed by the flows.

People ran for their lives

as their surroundings went up in flames

and the sky turned blood red.

The pastor also describes how both the animals

and the people at that time, at the same time,

started to develop

what appeared to be strange diseases.

The animals had deformed claws

or very deformed teeth.

The people also had lumps under their skin, also problems

with their mouths and their teeth and were dying.

The animals were dying and the people were dying as well.

And of course, for people at that time,

this was like a visitation from God.

This was something they'd never before.

This was the wrath of God is what they thought.

I really don't think that's the correct explanation.

I think it's to do with how volcanoes work.

Colin Devey examines the volcanic rocks

for clues about why both humans

and animals succumb to this strange, mysterious disease.

What I can read in the rocks is that they're full

of bubbles, and that's probably the most important thing

'cause it says that these were very gas rich lavas.

Obviously, the gas is no longer in these bubbles now,

but people have been able to analyze

what gases came out of there.

Along with carbon dioxide,

traces of two other gases were found.

The first one was fluorine, it's a poison.

And the symptoms of fluorine poison are exactly the things

that the pastor wrote about.

That's what caused those deformities of animals and humans.

The second gas was sulfur,

sulfur dioxide.

Now, sulfur dioxide spread around half the globe

and caused in Europe, for example, a year without summer.

Now it does that because sulfur dioxide in the atmosphere

connects to water, makes tiny, tiny droplets

of sulfuric acid, which block the sunlight.

So they reduce the temperature of the earth,

a year without summer, the plants don't grow as well.

Harvests fail, people starve.

These gases were also emitted

at the end of the Permian,

but on a completely different scale.

(gentle music)

Now imagine that happening over a million years,

over and over again.

We know the Siberian Traps are a great big pile

of huge lava flows.

So maybe every 100 years, 1000 years,

the world was faced with a global catastrophe of cooling,

of no sunlight.

(gentle music)

Because of the simultaneous emission of CO2,

a warm greenhouse climate was repeatedly established

before it would give way to the next cold phase.

And you've just got adapted to that.

And then the world turns into a balmy paradise.

I mean, how do you make that U-turn?

It's like riding a rollercoaster.

You're on the steep hill

and all of a sudden you're going up the other side

in terms of climate and your environment.

And that's probably, it's probably like a heavyweight boxer.

You know, the sulfur dioxide kind of pummeled you

and then the carbon dioxide took your chin off.

This could be one explanation

for the global mass extinction on land.

But the great dying

had an even greater impact on marine life.

So, were the volcanic eruptions truly responsible

for the catastrophe?

Kiel, Germany,

at the GEOMAR Helmholtz Center for Ocean Research,

geochemist, Dr Hana Jurikova

takes a close look at certain marine animals

for clues about what led to the disaster.

So what we have here are Brachiopods.

These are really unique animals

that have been around on earth for more than 500 million

of year since the beginning of Cambrian.

And they have changed very little since.

By analyzing the Brachiopods,

Hana hopes to find out

how the worst mass extinction in Earth's history unfolded.

So these fossils that we have here were deposited

at the bottom of the TEUs Ocean 252 million of years ago.

And what is really important is that some of them deposited

before the Permiandransic mass extinction,

and some of them like this one right after.

The fossil remains

of organisms like Brachiopod contain clues

about what happened on earth in the past.

By comparing the chemical composition of Brachiopod shells

that lived before the mass extinction

and after the mass extinction, I hope to find out

what caused a great dying.

The Brachiopod record a history

of the ocean's acidity in their shells,

and the analysis reveals that it increased significantly

at the end of the Permian, Hana can determine

historic acidification in an experiment

with living brachial pots, by measuring the pH levels.

(water bubbling)

Now I know that the ocean pH in the late Permian Ocean

was around eight.

In fact, very similar to what we have in the oceans today.

Right after the mass extinction,

the oceans have become very acidic

and the pH have dropped values of 7.5.

This has happened in a very short time,

only maybe 10,000s of years.

This is just a habit in the geological time.

It's way too fast for any organisms to really adapt to it.

This was way too swift, this was a death sentence.

Acid has dire consequences for animals

that build calcium carbonate shells.

Many organisms living in the late Permian Ocean

build calcium carbonate shells

just like this coral over here.

When the ocean becomes way too acidic,

they can no longer build their shells or skeletons.

Let's see what happens if we put some acid

on this coral here.

Hana wants to show

how acidic waters impact marine life.

The experiment reveals the devastating effects

of acidification on organisms

that rely on calcium carbonate shells,

the coral dissolves.

Countless animals were doomed to die in the acidic oceans

of the late Permian.

(tense music)

Food chains began to collapse

and one species after another died out.

It was the last gasp for prehistoric life on earth

and the deadliest time in our planet's history.

But what caused this massive acidification?

Increased levels of CO2

in the atmosphere would certainly acidify the oceans.

But was the CO2 released

by the Siberian Traps significant enough?

From research we know today

that the Siberian Traps released more than 387 billion

of tons CO2 to the atmosphere.

For comparison,

this is more than 40 times the amount of carbon

if we were to fire up all the fossil fuels on earth today.

Despite the huge amount of CO2, Hana knows

that it wouldn't have been enough.

Something else must have happened.

Although this was unbelievably extreme, I do not think

that the Siberian Traps were enough

to acidify the oceans in such a short time.

The huge amount of CO2 must have come from lava burning

available fossil fuel reserves on Earth

during that time, I think

that the Lake Permian world was just burning.

When ancient fuels ignite,

they set off widespread wildfires

that release even more carbon into the atmosphere.

As the oceans acidified, the land burned.

It was hell on earth.

How could any life survive this inferno?

(birds chirping)

In South Africa, paleontologist Roger Smith

is trying to answer this question.

The famous South African fossil hunter James Kitching

left notes about a Gorgonopsian

that he found in a Triassic formation.

The scientific community believes

that this predatory species

did not survive the Permian mass extinction.

So finding one in Triassic soil would be incredible.

(gentle music)

Here we are on Fairydale,

and this is that point on the map on James Kitching's map

where he put the pencil mark

and he had marked where the Gorgonopsian had come from.

And that mark is just down over there,

that's the position of it.

So our job now is to see whether we can find another one.

So students, this is a Gorgonopsian.

This was the apex predator.

And your mission today is to find more of this, so let's go.

(gentle music)

Dr. Julian Benoit from the University of

has done the research.

His students have scanned the entire area,

marked by James Kitching,

but didn't find anything resembling a Gorgonopsian fossil.

Roger and Julian decide to examine the area themselves.

So what's this, Roger?

Yes, look at this.

This is a sandstone tube going down

into the floodplain mud drops.

You can see the levels of the floodplain,

and this is definitely cutting down through it.

It used to be an open hole, so it must have been dug

by an animal.

And if that animal was digging holes here,

it must have been a survivor of the mass extinction.

So we need to find this animal.

The team hasn't found anything yet,

but they are certain that the fossil remains

of the tunnel building animal

in the Triassic formation will be found nearby.

(gentle music)

Look this bone over there, Roger,

here, some bone there.

Look at that.

Yeah, something exposed right here.

Okay.

What is that?

I think that is a skull.

Yes, this is the right orbit or the right eyeball.

And that's the top of the skull.

And this must then be the snout.

Yeah, it's the mouth coming in here.

You know, I think this is Lystrosaurus

and it could well have been the animal

that dug that burrow.

(upbeat music)

Like other Dicynodons, Lystrosaurus

only had two tusk like teeth, which had used for defense

and to tear apart small predators.

Even though it was a herbivore,

it had a horny beak for snipping off parts of plants

and was about the size of a powerfully built pig.

Its shoulders and hip structures

indicate that it moved with a semi crawling gate.

Its front legs were even more robust than the hind ones,

and were used to create burrows

where it sheltered and nested.

Roger decides to bring the fossil

to the University of Cape Town.

Here, Poaleo biologist, Professor Anusuya Chinsamy-Turan

will look at it to see if there are clues

as to how the animal survived the mass extinction.

Hey, Anusuya.

Roger, wow, what have you got this?

Yes, so I've just been out in the field

and collected this for you.

I haven't actually looked underneath it yet.

It's all there, and lower jaw.

Wow, that's amazing.

While Lystrosaurus lived in the Permian,

this one clearly survived the Great Dying.

By taking thin slices of its bone, Anusuya is able

to learn more about the animal.

So when we look at the bones of the Triassic Lystrosaurus,

it clearly indicates

that they had a faster growth rate

than the Permian relatives.

And this is an important adaptive strategy

because it means that they would be able

to grow more quickly, reach adulthood quicker,

and be able to reproduce quickly.

And this is a very classic strategy for survivors

of such a catastrophic event.

But Professor Chinsamy-Turan

can determine more about this Lystrosaurus

from the makeup of its head.

So one of the very distinctive characteristics

of Lystrosaurus

as compared to any other Dicynodons is the fact

that it's snout turns downward.

So if you look at the skull here,

these would've been the orbits

and the snout actually turns down.

So compared to the other Dicynodons where the skull,

where the snout actually projects forward,

this immediately tells us

that they were eating different food substances.

The paleo biologist is certain

that diet played a key role in the Lystrosaurus survival.

When we think about the end of the Permian, we know

that it was a very tough time

for both the plants and the animals.

And during the drying out times,

only the really tough vegetation probably would've survived.

So if Lystrosaurus survived,

we think that it probably survived

because it was able to eat the tough vegetation

that may also have survived at the end of the Permian.

The ability to dig tunnels

for shelter from harsh climate shifts,

along with the capacity to feed

on the few things that remained were essential for survival.

Lystrosaurus is a prime example of how life

always seems to find a way.

Even in the face of the worst catastrophes.

Throughout the Paleozoic era,

many fascinating animals emerged

and the three major extinction events

wiped out most of them.

But even the great dying,

the worst extinction in Earth's history

couldn't destroy all life.

The emerging Mesozoic era would see the rise of the largest

and most fearsome of all land creatures

that ever roamed our planet.

The dinosaurs, each catastrophe

and its extinction event drove evolution forward

and ultimately led to the life we know today.

(dramatic music)

(dramatic music)