All language subtitles for History.Of.Life.Series.2013.S01E05.1080p.AMZN-WEB.DL.DDP20.H.264-iND_track3_[eng]

*

*

A life has expired.

Most species that ever
existed on the Earth,

maybe even 99 percent
of them, are extinct.

This kangaroo is no
longer of this earth.

Oftentimes, death comes at
the most unexpected hour.

Of course it does remove
sometimes, whole groups.

But, it is also a
creative force.

Five mass extinctions
have occurred during the

4-billion-year
history of life on Earth.

Species died off
because they were weak,

or because they could
not adapt to changes

in the environment.

Some succumbed to
sudden disasters which had

never before occurred.

But the extinction
of one species was an

opportunity for another.

This is the story of the
destruction and creation

brought on by
mass extinctions.

*

*

We are on our way in search
of Earth's first animals.

This is the Flinders Ranges,
a mountain range

in Southern Australia.

There is no
human presence here.

Instead, the area is
populated by wild animals.

Dr. Jim Gehling hangs
precariously from a cliff

looking for something.

He is a paleontologist from
South Australian Museum

who has been
researching the fossils found

here for the past 30 years.

He finally
discovers something.

This is the fossil of
a creature belonging

to the Ediacara biota.

Before the time of
the Ediacaran fossils,

we only had
microscopic fossils.

For 3 billion years, nothing
that you could see with the

naked eye, and
then, very rapidly,

we see these strange creatures
appear in the fossil record.

These creatures which look
like leaves might have been

rooted to the ocean floor.

They swayed in the current
while subsisting on the

nutrients
floating in the water.

Although some
had heads and tails,

many of the creatures seem to
have no means of locomotion.

Dickinsonia is the
most common species

amongst the Ediacara biota.

They were flat, creased
creatures which had neither

a mouth nor muscles.

The smallest were as
tiny as a grain of rice,

while the largest creatures
grew as large as a cushion.

None of them so much as
resembles the creatures

living on Earth today.

So, what was the environment
they lived in like?

They lived in the sea
600 million years ago.

Species of the
Ediacara biota lived in all

the oceans of the world.

Most of the biota
lived stationary lives,

secured to the ocean floor.

And they
subsisted on the plankton

floating around in the water.

While there was a diverse
array of these creatures,

they were completely
different from the creatures

living on earth today.

Within the Ediacara
biota, we have some

truly weird creatures.

And we see
nothing like that today.

So we assume that
these things did not survive

into the Cambrian period.

They were only known in
the Ediacaran period.

Although they were the first
animals to inhabit the oceans

some 6 hundred
million years ago,

they all became extinct before
the Cambrian period arrived.

Next, we set out for a place
where clues to their mass

extinction can be found.

This is another area of the
Flinders Ranges where fossils

from the Ediacara
biota have been found.

These slanting
geological strata record the

history of life on Earth.

These sandstone rocks are
like pages in the geological

history of the
evolution of life.

On my right, we have the
sandstones of the Ediacaran

period with the soft-bodied
fossils of the Ediacara biota.

And here I stand
on a boundary.

We move across a most
important boundary.

The base of the Cambrian
and the beginning of the

Cambrian explosion of life.

This is a geological stratum
from the Cambrian period.

Although they merely look
like fissures in the rock,

the cracks are evidence that
a new page had been turned

in the history of evolution.

This is a fossil from
the Ediacaran period.

They are trails left by
a creature that crawled

around on the ocean floor.

They are noticeably different
from the trace fossils from

the Cambrian period.

This difference reflects
the end of one period and

the beginning of another.

Once animals evolved that
could eat other soft-bodied

animals, then, the only
animals that could survive

could either swim fast, make a
protective cover or a shell,

or if they had
neither of those abilities,

they had the muscles to dig into
the seafloor and hide there.

As it turns out, the fissures
in the rock are actually

fossilized holes that
creatures dug into the sand in

order to hide from predators.

Here in the Flinders Ranges,
there is a borderline between

the Ediacaran and
Cambrian periods.

There is another Cambrian
fossil on this rock that

Dr. Gehling is kneeling on.

This creature had a hard
covering around its body.

In this way, life evolved
in order to adjust to the

changing environment.

500 million years ago, Earth's
oceans were teeming with

creatures in a wide
array of shapes and sizes.

But something
changed in the relationship

between the creatures.

Suddenly, they realized
that there was food to be had

besides the plankton
floating in the water.

They could prey on each other.

In this way, animals began
to prey and be preyed upon.

And it was around this time
that hard protective shells

and muscles appeared.

So, what effect did such a
change have on the creatures

of the Ediacara biota?

This is a fossil
of two Dickinsonia.

They are spaced apart, as if
uninterested in each other.

Animals from the Ediacara biota
did not prey on other animals.

Instead, they subsisted on
nutrients floating in the sea.

But the change in
the environment

proved to be fatal to them.

An animal which was
soft-bodied like Dickinsonia,

a big sheet of meat
lying on the sea floor,

it's dinner waiting for an
animal that could eat it.

In the end, the
Ediacara biota became extinct.

While these once microscopic
creatures managed to grow

significantly in size,
they could not adjust to the

appearance of predators.

That's why they are
called 'a failed experiment'.

This rocky and barren terrain
was once the stage for the

rise and fall of
Earth's first animals.

They are testament to the
transient nature of life.

So, were the species that
adjusted more actively to this

change able to
avoid extinction?

The trilobite which first
appeared during the Cambrian

period and survived for 300
million years could be called

'a witness of Evolution.'

These creatures were able to
survive and flourish through

two mass extinctions
thanks to their quick and

varied adaptations to changes
in the Earth's environment.

Trilobites are capable of
very rapid evolution and this

applied even towards
the end of their history.

Some of the trilobites that
went out at the end of the

Ordovician had been
around in the oceans

since the Cambrian period.

So one could say that
they were themselves already

tremendous survivors.

Trilobite fossils
are extremely common.

When one takes into account
that the average species lasts

for 5 million years
before it goes extinct, the

trilobite's 300 million years
of survival is an amazing feat.

As their name indicates,
trilobites can be

divided into 3 sections.

They wore a hard shell over
their backs for protection

from hungry predators.

Also, they were equipped
with jointed appendages which

allowed them to
move very quickly.

Even the earliest of
their species had

well-developed eyes.

And they came in a
wide variety of sizes,

with the smallest being as
small as a fingernail and the

largest being as
large as a cushion.

These creatures were most likely
heavily preyed on in the seas.

Some fossilized trilobites
have chunks bitten out of them.

So, how did they
protect themselves?

Many of the trilobites that
survived the End-Ordovician

extinction event were
capable of rolling up.

This shows you how beautifully
adapted they are, the head and

the tail actually lock together
in some of these forms.

So if you're like that, you're
protected from the action

of an attacking predator.

Its soft underbelly was the
most vulnerable to attack.

But by rolling up
in this manner,

the trilobite could
keep safe from predators.

This was the first feature the
trilobite evolved in order to

survive in the predatory
waters of the ancient seas.

But that wasn't all.

This is the head of the
trilobite as seen from above.

This trilobite has a
pair of compound eyes.

It probably saw the world
through thousands of tiny

hexagonal windowpanes.

The waters that the trilobite
lived in were full of

predators hungry for a meal.

So it was extremely
advantageous to be able to

detect the movements of
potential predators and prey.

They had really quite
sophisticated visual systems,

even the early ones.

But some of the later ones
evolved really sophisticated.

Under a microscope, the
eyes of the trilobite are as

intricate and beautiful as
a finely-carved sculpture.

The eyes were so advanced that
they could focus on objects.

This was another adjustment
necessary for survival.

But the evolution of the
trilobite did not stop here.

It protected itself using
fearsome spines and hard armor.

Sometimes, the protective
spines were so large and

elaborate that they
looked lugubrious.

But even these were attempts
to adjust to the hostile

environment surrounding them.

So, were these heavily armored
creatures the last to survive?

Professor Suzuki Yutaro
of Shizuoka University,

an expert on trilobites,
offers us an entirely

unexpected answer.

The trilobite that managed to
survive as its more elaborately

armed kin slowly died off
was in fact quite ordinary.

This tiny 4-centimeter-long
trilobite was the last to

remain until the
species died off completely.

Instead of specifically
adapting itself to various

conditions around it, the
trilobite proliferated quickly

thanks to its small size,
and was able to survive longer

than its more
elaborately designed cousins.

Earth changed constantly
during the 300 million years

of the trilobite's existence,
but the creature was able to

adapt to these
changes and survive.

Nevertheless, there were
some changes that were all but

impossible to prepare for.

It's just bad luck if you're
in the wrong place at the

wrong time, and certainly
at the end of the Permian,

as much as 90 percent
of species went extinct.

So this is almost all of
life and is probably

more sensible to think
about the 10 percent who

survived as just being lucky.

Next, let us investigate an
incident that occurred at the

end of the Permian
period 250 million years ago.

This is a geological stratum
from the Permian period

located in Meishan, in
Zhejiang Province, China.

This band of dark rock
indicates the passage from one

geological period to another.

The slanted layers of
rock are marked with

letters and numbers.

They indicate the era
when the layer formed.

It is here that traces of
Earth's most devastating mass

extinction can be found.

These rocky mountains harbor
clues of a chilling past.

So, what exactly happened on
Earth 250 million years ago?

Around the end of
the Permian period,

great cascades of lava began
to gush out of a volcano near

what is modern-day Siberia.

The lava flow covered the Ural
Mountains and Lake Baikal,

and reached all the way to
Kazakhstan in the south.

This endless river of
lava solidified to create

a layer 20 meters thick.

The lava from this greatest
volcanic eruption in Earth's

history covered an
area roughly equal to

the American continent.

Creatures were helpless in
front of this massive disaster

whose scale was unprecedented.

This disaster
triggered even more disasters.

The smoke and ash which
gushed out with the lava

filled Earth's atmosphere.

The planet's temperature rose
by 6 degrees Celsius due to

the greenhouse effect
brought on by carbon dioxide.

Sulfur dioxide and
chlorine mixed with the air,

causing acid rain to drench
the earth and make its soil

uninhabitable to any
form of plant life.

Also, with the balance
of the atmosphere broken,

the solid methane in
the oceans began to melt,

causing earth's ecosystem
to spiral into chaos.

This was the greatest
mass extinction in the

history of life, with 97
percent of aquatic animals

succumbing to extinction
and 70 percent of terrestrial

vertebrates dying off.

When natural disaster
rears its ugly head,

no creature can withstand it.

But, it is only a matter of
time before life takes root

once more and flourishes.

This was not so with the mass
extinction that occurred at

the end of the Permian period.

What was the reason that this
extinction event was so much

more devastating than
similar events in the past?

Professor David Jablonsky of
the University of Chicago is

an internationally-renowned
expert on mass extinctions.

We asked him what factor played
the biggest role in determining

whether a species would
survive a global disaster.

So it's a real difference
in being widespread,

having your evolutionary
eggs in more than one basket,

as opposed to being concentrated
in just one small area.

Even if those lineages are
very well adapted to the

conditions before
the mass extinction,

unless they're widespread,
they're in serious trouble.

Earth's plate
shifts endlessly,

moving the continents with it.

Sometimes, the continents
become clustered together.

Such was the situation at
the end of the Permian period.

In other words, animals were
clustered together as well,

leading to a
disastrous result.

Broad geographic ranges of
entire evolutionary lineages

whether they are found
on multiple continents,

seems to control the
survival of major evolutionary

lineages, and other features
that used to matter go away.

So, that means that
the short, sharp,

extinction events have a
disproportionate effect on

the evolutionary process.

So, how did life
resurface after the demise of

most of Earth's creatures?

First, a single seed
must have been carried

onto shore by the waves.

Full of vitality, such seeds
became vast plains of grass

and lush forests, creating an
environment hospitable to life.

This newly created
ecology opened the doorway

for new species, attracting
animals such as small

reptiles that fed on plants.

Also, birds flittered in
to feed on the berries and

fruits, spreading
their seeds even farther.

Sometimes, during the endless
evolutionary cycle of life and

death, the fate of life on
earth takes an unexpected turn.

This is Gubbio, a town
located in Northeastern Italy.

People stroll leisurely
amongst medieval buildings.

Past and present coexist
in peaceful harmony here.

But in the mountain on
the fringes of the town,

there are vestiges of a mass
extinction event that took

place 65 million years ago.

This is part of the
Apennine Mountains,

which were once the seabed
until they rose up around the

time the
Mediterranean appeared.

There is a geological stratum
from the end of the Cretaceous

period located on the roadside
in the Bottaccione Valley.

These slanted
geological strata bear the

traces of scientific research.

The strata harbor the secrets
of a truly horrific event.

Called the K-T boundary, the K
and T stand for the Cretaceous

and Tertiary
periods respectively.

This ordinary looking layer of
rock drew scientific interest

due to the
presence of a rare metal.

The K-T boundary contained
10 times the iridium found in

other geological strata.

Meteorites which fall from the
sky often contain metals that

are extremely rare on Earth.

Iridium is one such metal.

Some scientists even claim
that all the iridium on Earth

is the result of collisions
with asteroids and meteorites.

The iridium concentrations found
in Bottaccione Valley are also

traces of an asteroid impact
which occurred 65 million

years ago and had a devastating
effect on life on Earth.

Let us find out more
about this incident.

After the mass extinction that
occurred at the end of the

Permian period, the
new masters of the

Earth were giant reptiles.

They ruled supreme
over land, air and sea,

and were Earth's
dominant predators for

nearly 200 million years.

Although the predators' large
size was an advantage when

hunting prey, it left
them vulnerable to sudden

changes in the environment.

Moreover, there was no way
that they could prepare for a

catastrophe caused by an
extra-terrestrial event.

This is a crater 1.6
kilometers in diameter and 170

meters deep, located in the
middle of the Arizonan desert.

It's the impact site of a
meteor that collided with

Earth around 50,000 years ago.

The vertical geological
strata are testament to the

awesome power of the impact.

Scientists calculate that the
crater was created by a meteor

50 meters in diameter
travelling at over 10

kilometers per second.

What would happen if an
asteroid 200 times larger

than the meteor that
created this crater,

collided with the Earth?

Some 65 million years ago,
that is exactly what happened.

The asteroid fell in what
is known as Mexico today.

At the time, North and South
America were divided by a sea.

Scientists say that the
impact was similar to having

Mt. Everest collide
with Earth travelling

at the speed of a bullet.

Countless dinosaurs were
killed by the great ball of

fire that fell from the sky.

None could prepare for
such a cataclysmic disaster.

But the initial impact
was just the beginning

of an extended tragedy.

Great plumes of black
ash rose up into the sky,

causing acid rain to fall.

And clouds of sulfur
dioxide hid the sunlight,

causing the
temperature to plummet.

The plants were the first
to succumb to the sudden

change in the environment.

But they were quickly followed
by plant-eating dinosaurs and

the predators
that fed on them.

With the sudden
scarcity of food,

the large size of the dinosaurs
proved to be a tragic weakness.

But this most recent mass
extinction was a blessing in

disguise for one species.

It also was an important
event for humankind.

People might tend to think
of extinction as a disaster.

Well, it is a disaster for a
short time for the organisms

that exist prior
to the extinction,

and of course it does remove,
sometimes, whole groups.

But it is also a creative
force because after the

extinction, ecological
opportunities are open.

Niches are vacant for new
organisms to move into,

for new adaptations to occur.

65 million years ago,
an asteroid which was 10

kilometers in diameter,
collided with the Earth.

While the dinosaurs were
powerless to avoid the

resulting chaos, Eomaia, the
tiny mammal, sought shelter.

Even before the disaster,
these tiny creatures only came

out at night in order to avoid
the much larger dinosaurs.

They were at the
bottom of the food chain.

Years passed by.

And around the time when the
effects of the most recent

disaster began to fade, this
mammal was preparing to open a

new chapter in the
history of life.

Unlike dinosaurs whose large
size proved to be a fatal

shortcoming, the tiny,
warm-blooded mammals were able

to survive the
mass extinction.

Ironically, the tiny
size of the creatures,

which was a
weakness in the past,

was the factor which
allowed it to survive.

And when the predatory
dinosaurs became extinct,

it was these mammals that
began their dominance of earth.

The mass extinction turned out
to be a gift for these small

and frail creatures.

After the demise
of the dinosaurs,

the mammals began to
spread at a breakneck pace.

Their warm blood helped
them adapt to the increasingly

seasonal climate of the Earth.

The mammals took on a diverse
array of sizes and shapes,

and each species developed
characteristics which helped

it adapt to its
new environment.

Mammals whose defining
characteristic was the fact

that they gave birth to
live young and reared them,

continued to evolve.

Until finally man, the
crowning achievement of

mammalian evolution appeared.

So, what effect did man with
his hyper-developed brain,

have on the
natural environment?

have on the
natural environment?

This is Naracoorte
Caves National Park in

Southern Australia,
which has been designated as

a UNESCO World Heritage.

Professor Gavin Prideux of
Flinders University passes a

dark and narrow passageway
and climbs down into a cave.

This is Victoria Fossil Cave.

Thought to be a giant
sink hole in the past,

the floor of this cave is strewn
with countless animal bones.

The fossilized
remains of some 45,000

animals are preserved
in this cave alone.

One can ascertain from the
large size of the bones that

the animals
themselves were quite large.

There are remains of a
kangaroo that was over two

meters in height as well as
bones of a 6 meter long lizard.

So, how did these animals
meet their death on this cave

floor, 50 meters below
the surface of the earth?

After the animals fall
in, they can't escape,

and they either die on
impact or they die of thirst

or starvation or injuries.

Their remains get incorporated
into the sediments and they

sort of slide down
through water and just gravity,

and mixed up also from other
animals trampling on top and

that is how we excavate them.

Australia possesses a
fascinating ecosystem.

It was originally part of a
massive supercontinent called

Gondwana located in
the southern hemisphere.

This continent
also included Africa,

Antarctica, South
America and India.

But 35 million years ago,
Australia became separated

from this continent, and became
home to a unique ecosystem.

There are many species
in Australia that cannot

be found anywhere else.

This is the result of millions
of years of isolation.

This is also the case
with the animals fossilized

in Victoria Fossil Cave.

For some reason,
placental mammals could

not take root in Australia.

Instead, a wide
array of marsupials,

that is mammals with pouches,
proliferated on the continent.

Such animals include a
kangaroo with a much shorter

face than the
kangaroos of today.

Thylacoleo carnifex, the
marsupial lion which was the

apex predator of the
Australian continent.

And Diprotodon, the giant
wombat whose massive size can

be gleaned by the size
of its enormous jawbones.

So, how were these
animals able to grow so large?

A hundred thousand years
ago, Earth's climate became

increasingly cold and dry.

And the only plants able to
survive in this environment

were nutrient-poor.

In other words, herbivores had
to eat large amounts of food

in order to gain the
necessary nutrients,

and this resulted in
their growing larger in size.

The predators that fed
on these herbivores also

had to grow larger in size.

The marsupial lion which
was the apex predator in the

Australian ecosystem weighed
more than 150 kilograms.

It would hide in the
bushes and pounce on prey,

slashing the victim's neck
with its large saber teeth.

The largest
kangaroo in Earth's history

grew over 2 meters in height.

It fed by picking and feeding
on leaves using its front legs.

Diprotodon, an herbivore
which weighted 3 tons,

usually lived in
herds by the water.

The large size of these
animals was the result of

adapting to an
environment which was

becoming increasingly barren.

But this adaptation alone
proved to be insufficient.

This was because of a new
species which hunted and lived

in an entirely
different manner.

What was this species
which caused the downfall

of these large animals?

One is that they were
hunted to extinction by

people when they
first arrived in Australia.

People arrived 60, 50-thousand
years ago and make the fauna

become extinct after that.

One of the other explanations
is that it was the lighting of

fires by people that changed
the nature of the vegetation,

wiped out the food plants
the mega fauna were adapted to

eating and then they
became extinct and then their

predators became extinct.

Even the marsupial lion
which once ruled supreme,

was no match for this
new species which was

armed with sharp spears.

To man, these giant
mammals were merely a rich

source of fat and protein.

The fire that early man
used to hunt would spread

uncontrollably, destroying
the habitats of these animals.

To make matters worse, the
climate changed drastically.

Man coexisted with these
giant animals for 20,000 years.

But in the end, the
animals fell victim to

man's fire and spears.

Unlike other animals, humans
stood and walked upright.

So their hands were free to
make the fire and tools with

which to overcome
their weaknesses.

Although man's only advantage
was his highly developed

brain, he used it to make the
tools necessary to hunt and

kill animals much
stronger than him.

Man was not an especially
vicious or violent animal.

He merely did what he needed
in order to survive, and this

brought about the unfortunate
demise of other species.

So, was this an unavoidable
course in evolutionary history?

Humans used different devices
to encourage its own species

to increase and if this
has an impact on totally

unrelated species,
then so be it.

The whole process of evolution
is an all encompassing

complex panorama.
that takes advantage of

every conceivable
niche and opportunity.

It's the most opportunistic
and selfish system that

you can possibly imagine.

Man's tools have
become far more advanced,

but even now, he is
in constant struggle

with the nature around him.

It is all but impossible to
draw the boundary between the

destruction that is
necessary for man's survival,

and the destruction wrought
by man's unnecessary greed.

All we can be sure of is that
if this destruction continues,

man's days on
earth will be limited.

Whether man exists or not,
life on this planet will go on

as it has even through
the 5 mass extinctions

that have come and gone.

We are now back in the
Flinders Ranges where earth's

first life forms were born.

Dr. Jim Gehling is
investigating something.

It is a trace fossil, a
petrified trail that was left

by some unknown creature.

There's no way to know
what the creature was

doing or where it was headed.

Was on its way to find food?

It could have been
looking for a mate or running

away from a hungry predator.

There is no way to tell.

All we know is that this
creature is now extinct.

Maybe 9 out of every 10 of
these species went extinct but

the 10%, one in ten, are
enough to take that genetic

material into the future.

These may be the ancestors
of all modern animals.

The life form which was
born 600 million years ago,

grew in size,
proliferated and diversified,

only to disappear once more,
leaving all but a few traces.

And with its disappearance, it
made room for a new generation

of life to take
root and flourish.

In this way, the history of
life has been an endless cycle

of birth and death,
creation and destruction.

Extinction is an end of
everything but at the same

time, it is also a
beginning of everything.