All language subtitles for Eons Life and Death on Pangea S01E06 Who Survived the Great Dying and Why 1080p AMZN WEB-DL DDP5 1 H 264-RAWR_track3_[eng]

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Kallie Moore:
Around 250 million years ago,

at the dawn of
the Triassic Period,

life on Earth was on its knees.

This was the direct aftermath

of the most severe mass
extinction event in history--

the Great Dying--triggered by
colossal volcanic eruptions

and runaway global warming.

The Great Dying lasted
hundreds of thousands of years,

leaving the supercontinent of
Pangea scorched, desolate,

and unrecognizable from
the rich and dynamic world

of the Permian Period
that had preceded it.

More than 80% of the planet's
species had been wiped out,

and its shattered ecosystems--
both on land and in the water--

were now inhabited
only by a skeleton crew--

an eclectic band of survivors
from the Permian,

the last remnants
of the Paleozoic Era

of ancient life.

And foremost among them was

a tusked, beaked,
and stocky herbivore,

about the size of a pig at most,
called Lystrosaurus.

It's not the most immediately
impressive of ancient beasts,

but in the Early Triassic,
this little lumpy weirdo was

the poster child
for life on land,

or what remained of it,
at least.

Because, for a brief and,
frankly, pretty bizarre moment

in the history of life,

after Earth had suffered its
worst-ever mass extinction,

Lystrosaurus ruled
over the wreckage.

It was the big winner
of the apocalypse.

At some Early Triassic
fossil sites,

Lystrosaurus is so abundant--

and other species so rare--

that it alone makes up more than
75% of the vertebrate fossils

that researchers find,

and as much as 95%,
according to some estimates.

Lystrosaurus has earned
the title of a "disaster taxon,"

a term that scientists
give to groups that,

at least temporarily,

thrive in the aftermath
of an ecological crisis.

So few other survivors emerged

from the rubble of the
Great Dying that disaster taxa

like Lystrosaurus
were suddenly freed

from nearly all competition.

And even though much of
the Early Triassic was

still pretty hostile
to most life,

Lystrosaurus was lucky enough
to have

the right combination
of traits to eke out a living,

or at least a surviving.

Gabriel-Philip Santos: So for
a couple million years or so

following
the end-Permian mass extinction,

the surface of the Earth was
a mostly pretty bleak place:

hot, dry,
almost totally treeless.

And in the water,
a similar story was unfolding.

Marine life was devastated,

with only pockets of
surviving biodiversity

clinging on here and there
amongst the carnage.

The Triassic Period was
off to a rough start,

but it wouldn't stay
that way for long.

Blake de Pastino: Eventually,
those survivors from the Permian

would find themselves replaced
by a new wave of species,

and whole new complex ecosystems

unlike anything the world
had ever seen before.

The Age of Reptiles
was about to begin.

And while many features of
the era of ancient life were

lost forever,

many now familiar features of
the modern world emerged

as the planet recovered, too.

The aftermath of
the Great Dying was

not just the graveyard of
an old world

but also the cradle

of a new one.

Michelle Barboza-Ramirez:
The five times

when almost everything died--

or the Big Five mass
extinctions, as we call them--

are considered to be the most
destructive events in evolution.

But the fossil record also shows

that mass extinctions aren't
purely destructive forces.

By wiping the slate
almost totally clean,

mass extinctions open up
new opportunities

to surviving species that were
beyond their reach before,

suddenly catapulting
obscure groups

into the ecological spotlight.

And the pressure to survive
those extreme events

molds species in ways that leave
a lasting evolutionary legacy.

Ecosystems don't just
recover from mass extinctions,

they often reform in ways
that are radically different

from anything
that existed before.

And after the Great Dying, life
on Earth was changed forever.

This almost complete
reorganization

left such a clear signal
in the fossil record

that it literally marks

the end of the first era
of complex life on Earth,

the Paleozoic, which means

the era of ancient life.

And the ecosystems that rose
in life's middle era--

the Mesozoic--beginning

with the Triassic Period

were starkly different.

But that process took time,

and for basically
all of the Early Triassic,

the ecological recovery
on land was slow.

Having at least
one really abundant species

from the Early Triassic gives us
a rare and valuable window

into that world.

Because, while fossils of
other species from this time

are sparse, we have
thousands of Lystrosaurus.

Its tusks and beak
allowed it to access

and feed on tough,
dry-adapted vegetation,

and it could burrow
into the ground

to find shelter
from the elements

or from the occasional
surviving predator.

Plus,
its widespread distribution

across Pangea, from what's

now Russia to Antarctica,

suggests Lystrosaurus

colonized the far corners
of the supercontinent

relatively quickly,

thanks to its resilience

and ability to tolerate

a wide range

of environmental conditions.

All of these traits,

probably combined
with a healthy dose of luck,

allowed Lystrosaurus to survive
and even flourish

in the wake of the Great Dying,
when almost nobody else could.

Caroline Abbott:
One of the things

that makes Lystrosaurus

such a great animal
to study is that we

have it before
the extinction

in the latest Permian,

during the extinction
interval itself,

and then into
the earliest recovery

from the extinction,
the Triassic.

We have thousands of
fossils of this animal,

and Lystrosaurus survived

the end-Permian
mass extinction

in enormous numbers.

And in all those bones,

paleontologists have found clues
that paint a picture

of a world reeling
from environmental shock--

one so hostile that even
so-called disaster taxa

struggled at times.

Most of the fossils
that we find from Lystrosaurus

in the Triassic
are quite tiny.

We get this huge
overrepresentation

of juvenile specimens.

The fossil record shows
that Lystrosaurus

from before the Great Dying
lived up to around 14 years.

But after the event,
patterns of bone growth show

that most individuals were only
living around 2 to 3 years.

In the harsh, unforgiving
world of the Early Triassic,

Lystrosaurus evolved
to live fast and die young.

They likely reproduced
earlier and more often

because of their reduced
life expectancy

in these extreme conditions,

accounting for the abundance of
juveniles in the fossil record.

In fact, its flexibility

in adapting its development
and life cycle

may have been one of the key
reasons that Lystrosaurus

was able to persevere
as a disaster taxon.

But Lystrosaurus wasn't totally
alone in the wreckage,

and some of the other survivors

were just as dangerous
as the environment.

At the top
of the fragile food chain

of the Karoo basin and elsewhere

in the first million years or so
of the Early Triassic was

a leopard-sized therocephalian
called Moschorhinus.

Before the extinction,
Moschorhinus had been

just one of many medium-
and large-sized carnivores that

stalked the landscape of Pangea,

along
with the huge gorgonopsians

that were the apex predators
of the Late Permian.

But while
all those other big predators

disappear from the fossil record
around the mass extinction,

Moschorhinus persists--the last
large predator left standing.

Much like
the Lystrosaurus it hunted,

the fossils of Moschorhinus show

that it was forever changed by
the extinction event.

Remains of the predator
from before and after

show several
intriguing differences.

After the Great Dying,
individuals are smaller,

and studies of their bone growth
show that

while their growth period
was shortened,

their rate of growth
was actually faster.

This shrinkage seen
in Moschorhinus, Lystrosaurus,

and potentially
other Early Triassic species

has even been argued to
partly explain

a widespread
but little-understood

evolutionary phenomenon

dubbed the Lilliput Effect.

This is the same animal,

broadly speaking.
It's the same genus?

Yes, yeah.

Before and after?
Mm-hmm.

And that's significantly
smaller than this.

Yes, yeah.

In paleontology,
we find, oftentimes,

after mass extinctions,

small versions
of the fossils

that we were seeing
before the extinction.

But why? Like, what's
the advantage of that?

Animals that are investing
in a larger body plan

are not going to be able
to get the nutrients...

Oh.
to persist.

If you change your growth
trajectory such that you're

a smaller animal that
needs fewer resources,

you're growing fast
at a smaller size

and reproducing
more quickly.

That might be advantageous

to living in
a catastrophic environment.

Being smaller
but developing faster

might just be
the evolutionary strategy

that consistently works best
in a post-apocalyptic world.

But how did the ancestors of us
mammals--known as cynodonts--

survive?

Was it just luck?

Or did we have some evolutionary
tricks up our sleeves, too?

In the Permian,
the early cynodont species

had never ever gotten big

or committed
to highly specialized niches,

like so many other therapsids
had during their heyday.

Instead, our cynodont ancestors
had been

smallish generalist
carnivores that lived

fast, energetic,
and pretty scrappy lives,

chasing small prey
and dodging predators,

kind of like
the ferrets of their day.

You see, generalists
tend to be much better

at coping with environmental
instability than specialists,

who are highly adapted to and,
therefore, very dependent on

specific ecological conditions.

And in
the Early Triassic aftermath

lived cynodont survivors,
like Thrinaxodon,

a weasel-sized ancient relative
of ours that

shared its environment with
Moschorhinus and Lystrosaurus.

We've found
many of its fossil burrows,

sometimes with
a Thrinaxodon still inside.

In fact, Thrinaxodon is

the earliest known
burrowing cynodont.

This makes it
quite a trendsetter,

seeing as around 50% of modern
cynodonts--a.k.a. mammals--

still burrow today.

And scientists have
even proposed that burrowing

may have emerged in Thrinaxodon
and other cynodonts

as a direct adaptive response
to the hostile environment

of the Great Dying
and its aftermath.

It's a simple and common
mammal behavior today that

may have roots stretching back
to an ancient apocalypse,

and it's potentially
one of the main reasons

we're still around.

This skeleton
crew of animal life had it rough

for pretty much
the entire Early Triassic.

They were surviving,
but to even begin to recover

their former levels
of diversity and abundance,

they first needed their habitats
to recover.

And the geological
record suggests

that may have taken a while.

See, researchers have identified
a so-called "coal gap"

that spans about 5 million years

through
the entire Early Triassic

and into the Middle,

where no rock layers
from anywhere in the world

contain deposits of coal.

Now, coal is formed by
the compression of peat,

which, in turn, is formed by
accumulated plant material

in wetland swamps and forests.

So a lack of coal deposits
in the geologic record

suggests an almost total loss
of those plant ecosystems

for millions of years,

making it a pretty arid and
barren phase of Earth's history.

So Pangea had lost
its most diverse habitats--

forests and swamps--

and the marine realm had lost
its equivalent, too--reefs.

See, while the fossil record
on land shows a coal gap,

the marine fossil record shows
a reef gap

that also lasts throughout
the Early Triassic.

After being battered by
rising temperatures,

ocean acidification,
and a loss of oxygen,

80% of marine species died out.

From reef builders to trilobites
to sea scorpions,

many ancient features of
the world's oceans had vanished.

But there's evidence that
in certain places

and at certain times
during the aftermath,

a recovery was brewing
below the waves.

For a long time,
paleontologists thought

that while some groups achieved
unlikely success here and there

in the Early Triassic,

rich and complex ecosystems
still weren't really a thing

until 5 million to 10 million
years later.

But in recent years,
fossil discoveries

in places like here
in Paris Canyon, Idaho,

have complicated that picture
of Early Triassic Earth.

This site is way
more exciting

than it might seem.
Like, it's not that big--

it's only a couple
hundred feet long--

and it's here on the side
of the road, but it's

full of this really amazing
combination of animals that

are really surprising.

And those animals are really
important because they're

right in, like, the very
beginnings of the Triassic,

really not that long
after the Great Dying.

And they're helping us
understand, like,

how ecosystems were
really more complex

than we used
to understand.

In 2017,
paleontologists reported that

they had unexpectedly stumbled
on something amazing here

buried in the rocks--

the fossil remains of
a diverse marine ecosystem

from just around
249 million years ago,

less than three million years
after the extinction event,

when this area
was a warm, shallow sea

on the western edge of Pangea,
close to the equator.

It featured fishes, cephalopods,

crustaceans
and other arthropods,

sponges, bivalves, brachiopods,
and more,

all somehow thriving together

when they should have been,
well, dead.

This assemblage of species,
known as the Paris biota,

was a strange mix of ancient
holdovers from the Permian

and new species that
show up for the first time.

Brandon Peecook:
Oh, here we go.

Cool.

Right there. That spiral.

That's cool.
What is that?

Yeah, that's an ammonoid.

So it's an animal
called Tirolites.

It's super, super common.

We should find it
a bunch in here.

This is one of the animals
that actually lets us know

how old the site is.

There's another one
right there.

Oh, my g--Yeah, I told you.
They're everywhere.

They really are.

What other kind of
creatures

can we find in here?

So things
like squids and octopuses

and cuttlefish today,
they first show up

in the Triassic, and some of
the oldest fossils we have,

they're called coleoids.

That whole group are,
like, known

from this site,
like, right here.

But then there's also animals
we find here that, like,

shocked everybody
when they were first found

because some of them
are animals that,

like, disappeared hundreds
of millions of years ago,

or so we thought.
Uh-huh.

But here they are in
the early Triassic,

like, next to the lobsters.

Yeah, this is a little clam,
so, like, a bivalve.

Oh!
Like the little shell?

Yeah.
It's pretty cute.

We've seen some
brachiopods already,

but that's, like,
a nice, nice clam,

so a different kind of
little shelly guy.

This diverse community
somehow stitched together

a functioning complex ecosystem
in the wake of the Great Dying,

millions of years earlier

than many scientists had assumed
was possible.

And since the discovery
of the Paris biota,

similar evidence

of rapidly recovering
shallow marine ecosystems

have turned up elsewhere,

including in neighboring Nevada
and even as far away as China,

dating to as little
as just 1 million years

after the extinction event.

We understand
and expect to see

ecosystems not
really recovering

from the Great Dying
until, you know,

7 million, 8 million,
9 million years

after the event.

But this site's much,
much closer to the event

than that, and it's already,
like, really complicated.

So there's a lot of
surprises, right?

There's a lot of
geographic variety probably

in how life survived
and recovered

from the Great Dying,

which is really, really,
I think, exciting.

It means there's
so much more to learn.

We still have
a lot of open questions about

how such rich ecosystems
could recover so fast

from the worst disaster
of all time.

And in the years to come,

we may find the answers
to those questions.

But it's already clear that,

at least in pockets
of the marine realm,

life was showing just
how resilient it really was.

A new group of predatory
reptiles was on the rise

in the oceans of the Triassic:
ichthyosaurs.

Ichthyosaurs,
literally "fish-lizards,"

descended
from land-dwelling reptiles

that gave up on
the terrestrial realm entirely

and took to the water instead,

sometime around the Great Dying
or maybe even a little before.

The first real
ichthyosaur fossils we have

are coming, like,

right after the
end-Permian mass extinction.

And so you have to realize
that, like,

the extinction
is an opportunity,

and ichthyosaurs are
one of these groups that,

like, really takes
advantage

and becomes
full ocean reptiles.

With so little competition

in the aftermath
of the extinction,

ichthyosaurs diversified
rapidly,

as parts of many other
complex open-ocean food chains

were recovering.

And while they started small,

within just a few million years,
some of them would become

the largest animals
the world had ever seen.

And by the Late Triassic,

some even rivaled
modern whales in size.

The sudden rise of ichthyosaurs
in the wake of the Great Dying

led to the first true ocean
giants of Planet Earth,

a feature of our oceans
that we've had

in some form or another
ever since.

Eventually, above the waves,

life on land
began to recover, too.

About 10 million years
after the Great Dying,

we see evidence that
the landscape of Pangea

wasn't so desolate anymore.

Dense forests regrew
and spread across the world,

providing habitats
for new species.

This global reforestation left
signals in the geologic record,

like coal deposits
showing up again

as the vegetation that
formed them returned,

ending the coal gap.

And wood-boring beetles start
showing up again

in the fossil record, too,

reemerging after a gap
of their own at this time

as their
forest habitats recovered.

Complex terrestrial ecosystems
were reforming,

but this new era of life on land

would be different from anything
that had come before.

As the Triassic recovery
played out,

synapsids, including
our cynodont ancestors,

found themselves facing
intense competition,

and it came from
their ancient cousins

from the other side
of the amniote family tree.

The Triassic marked the start
of the Age of Reptiles,

and their dominance of
terrestrial ecosystems

would last for a very long time.

If Lystrosaurus
was so what,

resilient and adaptive
as a generalist

and it survived the thing

that destroyed almost
all of life on Earth...

Yeah.

then what happened to them?
How did their story end?

So Lystrosaurus

didn't live that far
after the Early Triassic.

It was really abundant
in the recovery interval

from the extinction.

But then as ecosystems
return to normal

and we start seeing a higher
diversity of species

going into the later parts
of the Triassic,

Lystrosaurus
disappears pretty quickly.

You would think that if
it's so good at surviving

the worst thing that has ever
happened to life on earth,

that it would be
fine competing

with a few reptiles
and Archosaurs

and other dicynodonts

that are persisting.
But, no.

That's really remarkable.
Yeah.

That's a heck of
an evolutionary strategy.

Like, when things go wrong,

that's when they're
really in their prime.

And then when things
settle down again,

the conditions become
more difficult for them.

Yes. Yeah.

It's like they're
adapted to chaos.

Just as ichthyosaurs were

the rising stars
of the Triassic oceans,

another group of reptiles was
vying for ecological prominence

on land--the archosaurs.

They started out as
a pretty obscure reptile lineage

that survived
through the Great Dying.

And as the planet recovered

over the course
of the Triassic Period,

they underwent an explosive
evolutionary radiation.

Archosaurs began filling
an array of ecological niches

that had been left mostly empty
by the mass extinction,

outcompeting and replacing
disaster taxa like Lystrosaurus.

Take the pseudosuchians,
for example,

a branch of ancient archosaurs
related to modern crocs.

They diversified into everything

from giant apex predators
to armored herbivores.

One group of archosaurs,
known as the pterosaurs,

even took to the skies,

becoming the first known
vertebrates in history

to master powered flight.

And somewhere in this explosion
of reptile diversity

was a lineage of
upright, slender archosaurs

that was about to give rise

to one of the most spectacular
animal dynasties

the world ever saw:
the dinosaurs.

The earliest
true dinosaurs arose

about 233 million years ago.

And they were
only side characters

compared to other branches
of the archosaur family tree.

But during the Late Triassic,
that suddenly changed.

Much of that archosaur
competition on land fell away,

and dinosaurs were catapulted
to the ecological forefront.

And just in time, too, because
Pangea was starting to break up,

and its fragments would carry
the dinosaurs over the globe

over the course
of the Mesozoic Era.

Their reign over Planet Earth
had begun,

but that's a story
for another time.

The Paleozoic Era
of ancient life was

well and truly over,

and life's middle era,
the Mesozoic, was in full swing.

But the story of the synapsids

that had lived and died on
Pangea continued

into the Age of Reptiles.

Because scurrying here
and there,

rustling through the undergrowth
of dense Late Triassic forests,

a pretty familiar group
had finally emerged: mammals.

They had evolved from a lineage
of cynodonts

that had been both lucky
and scrappy enough to survive

not just the Great Dying

but also the challenging

and increasingly competitive
world of the Triassic.

And by the Triassic's end,

cynodonts were
the only synapsids left.

Today, we mammals are
the last remaining branch

of what used to be
a huge, diverse,

and once-globally successful
synapsid family tree,

with roots stretching back
to the era of ancient life.

While synapsids had seemed
unstoppable in the Permian,

in this world dominated
by dinosaurs,

the earliest mammals became
mostly small and nocturnal

to survive--

quite literally
cast into the shadows.

Dimetrodon...

The Permian, in my eyes,

is more important
than the dinosaur age

because this is where
our roots come from.

You know, your cousin
is buried right here

290 million years ago.

Christopher Flis: This is where
humanity comes from in a sense,

and it's always
surprising us.

You know, every time we
think we know something new

about the Permian,
it changes our minds.

The Permian is
a really important

time period because
it is so early

in the evolution of
life on land.

And we're really getting
a snapshot

of how vertebrae animals

were exploring how to live
in this new place.

This is sort of where
the ancestors of the mammals

show up--our ancestors.

These dinosaurs that
aren't dinosaurs, really.

Rrr!

When you get, like,
a pack of dinosaur toys,

and it's in there
for some reason.

You know, you look at
a Dimetrodon,

you're like,
"Oh, that's a dinosaur."

But they're not dinosaurs.

They're actually a close
relative of mammals.

Dimetrodon
and the Edaphosaurus,

they are still very relevant.

The synapsid body plan,

the idea that something
could look and act

more or less like
the mammals would later on

simply isn't likely just
like any form of life.

And so the fact that
not only did that happen

but we have such a good
record of it here,

that success story is
just really cool.

Without this Great Dying,

we wouldn't have had Age
of Dinosaurs as we saw it.

So, you know,
for a paleontology person,

that's kind of cool.

But I'm a human first,
so I'm team synapsid.

So the fact that they
were knocked out,

some of the traits
that were required

to survive this event
led to us mammals--

assuming you're a mammal
watching this--

rising up again
and, in the Cenozoic,

taking it from there on.

And so that's why it's
such a big deal that

we were knocked back

to appreciate where
we are today.

With something as
terrifying as the Great Dying,

you know, when almost all life
was wiped out,

it's pretty inspiring in a way

to be able to see life
just carry on

and be resilient.

Studying the Permian
is really important

because we can really understand
so much of our story from that.

This is when so many things
go extinct.

This is when
so many things recover.

It's that really incredible
story of life on earth,

and being able to see it through
the lens of the Permian

and how life and death on Pangea
was happening,

it's... it's just really,
really cool!

Today, we're finally bringing

the epic saga
of the Permian Period

back into the light with us.

Because while the world
of the Permian is long gone,

it is no longer forgotten.

And while it
still doesn't always get

as much attention
as it deserves,

considering it was both
the best and the absolute worst

of evolutionary times--

its story is one that
we're slowly rediscovering.

252 million years
after the Permian ended,

at least some descendants

of the species that
lived and died on Pangea

are coming to know what it means
to be a living legacy

of one of the most pivotal and
radical chapters of deep time.