All language subtitles for Making North America Series 1 NOVA 2of3 Life 1080p

KIRK JOHNSON:
North America,
the land that we love.

It looks pretty familiar,
don't you think?

(explosion)

Well, think again!

The ground we walk on
is full of surprises

if you know where to look.

As a geologist,
the Grand Canyon is perhaps

the best place in the world.

Every single one of these layers
tells its own story

about what North America
was like

when that layer was deposited.

So are you ready
for a little time traveling?

I'm Kirk Johnson, the director

of the Smithsonian National
Museum of Natural History.

And I'm taking off onthe field trip of a lifetime...

Wow, look at that rock
right there.

That is crazy!

...to unlock the secrets of our
continent's incredible past.

In this episode, we going
to jump back millions of years

to a North America that's full

of all kinds
of unusual creatures...

Yikes!

...turning up in the most
unexpected places.

A 14-foot-long fish in Kansas?

MAN:
That's what I'm telling you!

JOHNSON:
It's a time when much of
the Midwest was underwater.

I'm on the hunt for clues
to the amazing connection

between our land and everything
that's ever lived here.

From the rise of early life...

NOAH PLANAVSKY:
What I'm holding in my hands

is a fossil that's
two billion years old.

Wow.

JOHNSON:
...to the destruction of the
biggest, baddest beasts

of all time.

(explosion)

It doesn't look like much,
but this layer is Armageddon.

"Making North America: Life,"
right now on
NOVA.

Major funding for
NOVA is pwith gleaming cities,ing:ld

almost half a billion people,

and still, some spectacular
wildlife.

But if we could rewind the clock

and travel back in time
millions of years,

life on our continent gets
a whole lot wilder.

Yikes!

That makes a grizzly bear
look like nothing.

This land is filled
with the bones

of some mind-blowing ancient
creatures that once roamed

and swam across a continent

that was completely different
from the familiar place

we call home today.

When you dig deep
and follow the clues,

you uncover
an incredible fact...

That powerful forces
in the ground beneath our feet

and the rocks all around us
have shaped every plant

and animal that's
ever lived here.

You just have to look to follow
the twists and turns,

the ups and the downs...

of North America's
incredible life story.

In an empty corner of Utah
lies a very special landscape.

I'm flying over a remote regioncalled the Kaiparowits Plateau.

I love this place because its
rocks contain a record

of one of the most important
chapters

in the history of life
in North America.

My guide for the day is
paleontologist Joe Sertich,

an old friend from the Denver
Museum of Nature and Science.

SERTICH:
Pretty good place to be
a paleontologist, huh?

JOHNSON:
Oh yeah, this is awesome.

JOHNSON:
What makes the Kaiparowits so
amazing for paleontologists

is that it's jam-packed full
of dinosaur fossils.

They're sticking out everywhere.

Hey, look at that!

All sorts of chunks of little
bone here, it looks like.

JOHNSON:This is a great place for using
my favorite little trick

for testing fossils.

Uh-uh, it sticks on the end
of the tongue.

It actually sticks really hard.

The little pores in the bone
will try and pull the water

out of your tongue,

and a real piece of fossil bone

will stick really hard
to the tip of your tongue.

But Joe hasn't brought me
all the way out here

to suck on a few broken bones.

He's got something much cooler
to show me,

the cast of a skull belonging
to a new species of dinosaur

discovered right here
that Joe helped identify.

SERTICH:
I think you're going
to like this.

Whoa, look at that.

Yeah.

This is the lower jaw.

Well, there's no doubt
that guy's a meat-eater.

Look at that, little
steak knives in his face.

Exactly.

Yikes.

That makes a grizzly bear
look like nothing.

SERTICH:
This is a dinosaur
called Lythronax.

JOHNSON:
Lythronax?

Lythronax isa pretty cool name.

It actually meansthe king of gore.

The king of gore?

Yeah.

JOHNSON:
Who came up with that name?

I did.
You did.

(both laughing)

That's one of the things
about finding dinosaurs,

you get to name them.

You get to come upwith the name-- exactly.

JOHNSON:
The really exciting thing
about the King of Gore

is that when you put flesh on
the bones that Joe found...

Lythronax looks a lot

like the much more famousand fearsome
Tyrannosaurus rex.

But it's ten million years
older.

Maybe he was
T. rex's
gr
eat-great-great-granddaddy.

80 million years ago,
all of North America,

not just the Kairparowits,

was home to creatures
like Lythronax.

And for the next
14 million years,

our continent was like
a dinosaur movie set

with a cast list featuring some
of the biggest superstars,

like
T. rex,
the hadrosaurs,

and my favorite dinosaur,
triceratops.

We know this because we find
their fossils

all over the place.

In fact, of all the dinosaur
species discovered worldwide,

fossils of more than a quarter
of them have been found here

in North America.

So the big question
for me is, why?

What was it about North America

that made it such
a dinosaur factory?

What was the continent like back
then that it could produce

such a diverse cast
of dino characters?

Well, before we can unravel this
mystery, we need to understand

the intimate connection between
life and the land.

It's a process that's been going
on since life first emerged

more than three-and-a-half
billion years ago,

long before the dinosaurs roamed
the land,

in a time before North America
even existed

and the earth was covered
almost entirely in ocean.

There's some intriguing evidence
for this link

in an unexpected corner
of the North American plate:

the Bahamas.

I've come here to see a rare
living fossil,

one that helped change
the earth itself.

Without it, life as we know it
might not even exist.

My guides are marine scientistsNoah Planavsky and Pamela Reid.

So what did you think whenyou first saw these things?

You feel like you've stepped
back in time

to early earth.

It's another world.
You'll see.

I've been waiting my whole lifeto see these things.

JOHNSON:But to see anything, first we'vegot to dive down about 20 feet,

where we'll have
a brief window of time

before powerful currents
threaten to sweep us away.

We're looking for one of theoldest organisms on our planet,

but as we descend, there is not
much sign of life.

Could it be hiding
behind these strange rocks?

Actually these rocks are the
very things I've come to see.

They're called stromatolites,

and believe it or not,
they're alive.

You can't see them,

but just beneath the surface
of these boulders

is a thin coating of bacteria.

Over thousands of years,
these microbes accumulated

layer after layer
of mud and sand

to build mounds
up to eight feet tall.

Today, living, growing
stromatolites like these

are extremely rare,

but these precious examples hold
the key to the evolution

of virtually all complex life.

I could stay down here
for hours,

but the current is getting
stronger,

and we don't want to get pulled
out to sea.

That was amazing down there.

The current really picked up.

It was rippingthrough there, too.

And that is actually why,

important reason for why
we have these stromatolites.

What's special about this spotthat allows them to be here?

Well, you noticed
a very strong current?

We were being hauled alongby that current.

REID:
And you also noticed

there were sand waves that were
going over the stromatolites.

That sand will actually bury
the stromatolites

for months at a time

And then unbury them again.

And unbury them again,

and that burial is
really important

to the existence
of the stromatolites.

JOHNSON:
When the sand is swept away,

the stromatolites are vulnerable
to seaweed and corals

that block the sun.

The sand protects them.

REID:
It keeps away the higher
organisms,

the seaweeds, the corals.

In early earth, there were
no corals and seaweeds

to compete, so they actually had

a much bigger territory,
and they dominated the planet.

For about 80%
of earth history,

stromatolites were kings.

JOHNSON:
That's a long, long time
to rule.

Stromatolites are the earliest
fossilized form of life

we've ever found.

NOAH PLANAVSKY:
What I'm holding in my hands
is a fossil,

a stromatolite
from North America.

It's two billion
years old,

almost two billion
years old.

Wow.

JOHNSON:
So how old do these things
actually get?

PLANAVSKY:The oldest examples we find are
3.5 billion years old.

JOHNSON:3.5 billion years-- I love that.

That's time, man.

3.5 is almost three quarters

of the entire history
of the planet.

So these organisms
have seen it all.

PLANAVSKY:
They're a continuous recordof life thriving on our planet.

JOHNSON:
So why were stromatolites
so successful?

Three billion years ago,

our planet was almost
unrecognizable.

Covered by enormous oceans,
there were no continents,

just hundreds of small
volcanic islands

belching out huge amounts
of carbon dioxide...

and even toxic substanceslike sulfur dioxide and arsenic.

Most creatures today would
suffocate in these conditions,

but the microbes that built
stromatolites

used them to their advantage.

PLANAVSKY:
The really clever thing
about these organisms

is they developed
a way to thrive

in the conditions back then,

in an atmosphere that would have
been toxic to life

as we know it today.

JOHNSON:
But how did they do it?

To find out, Noah and I wade
into the slime

of this shallow lake.

This stuff is slippery, man.

JOHNSON:
This place is teeming
with bacteria,

similar to the ones that live
on stromatolites.

Oh, look at that.

PLANAVSKY:
The same type of organisms

that form the stromatolitesare forming these mats.

Looks like kind of
a nasty black lasagna.

Smells bad too.

There's also some bubbles coming
off in the water, seems like.

PLANAVSKY:
Let's see what they are.

So I have a gas probe here.

Let's bury it in the microbialmat here and see what we get.

Very uppermost portion.

And it's what gas?

Oxygen.

Oxygen-- this is coming
out of the mat?

Exactly.

The waste product thattransformed our planet

is oxygen.

JOHNSON:
Oxygen a waste product?

That's what we breathe.

But these little microbes do
the opposite:

they take in carbon dioxide
and water and release oxygen.

It's called photosynthesis,

the chemical reaction
at the heart

of every green plant alive
on earth today.

This was the contribution
of the stromatolite bacteria

to early Earth.

In a place filled with volcanoes
and water,

over the courseof more than two billion years,

they pumped out so much oxygen

that the atmosphere changed from
what would have been

a deadly poison for us

into something that made it
possible

for life as we know it to exist.

So these things didn't onlyjust live in their environment,

they actually transformedthe environment

and made it livablefor other things.

Absolutely.

JOHNSON:It was a critical turning point.

Now a new kind of lifeform could
finally join the party:

creatures that didn't produceoxygen, but instead consumed it.

About 640 million years ago,
complex life took off,

with the evolution of primitive
animals like sponges,

followed a little later

by a group of jellyfish-like
creatures called Cnidaria,

the first animals to possess
nerves and muscles.

Over millions of years,
life grew ever more complex.

Fish got a skull and backbone
420 million years ago.

By this time, land had emerged,
so it wasn't long

before the first amphibians
hauled themselves

out of the water
and onto the shore.

This led to the evolution
of reptiles,

and then, more than 200 million
years ago, to the dinosaurs.

Which brings us right back
to where we started--

the big mystery.

What was it about this continent

that allowed so many kinds
of dinosaurs to thrive?

You can find one clue rightsmack in the middle of the U.S.,

in the Great Plains
of central North America.

For most people,

a drive across the Great Plains
is an exercise in boredom.

For me it's just the opposite.

As a geologist I think about
what's beneath the plains,

the stories that lie
beneath the prairie.

Just outside the town of Oakley
in western Kansas,

some strange but spectacular
shapes burst up

out of the plains.

They're called Monument Rocks.

This place is so cool.

The story goes that early
settlers crossing the plains

used these as landmarks
to help them navigate.

One of the most amazing things
about this place

is how much time it represents.

Just one inch of this chalk
is 700 years.

That means that a foot of the
chalk is 8,400 years,

or roughly the entire duration
of human civilization.

There's about 40 feet of this
stuff above me,

and there's another 300 feet
below me.

There's literally millions
of years represented

in this one place.

It's a snapshot of a time

when North America was going
through some major changes.

This place is filled
with fossils.

Hey, Chuck!

Long time no see.

Good seeing you.

Hey, Barb, how are you doing?

Good to see you.

JOHNSON:
And nobody is better
at finding them

than Chuck Bonner
and rbara Shelton,

who've hunted for fossils in
these rocks for over 40 years.

Let's go findsome fossils.

All right,
sound good.

Well, come on.

JOHNSON:
When I told them I was coming
by, they offered to show me

their newest discovery.

That's pretty cool.

How did you find
this thing, Chuck?

Well, I was searching alongthese slopes here

and found somebig bones sticking out.

That's cool.

What did you think when you
first saw this, Barb?

Lot of digging,
that's what I think.

Let's put a little
water on here, huh?

Yeah, let's bring it to life.

JOHNSON:
A little water reveals a skull
with some major-league teeth,

no question a vicious predator.

But this was no dinosaur.

These jaws belong to an
80-million-year-old fish

called Xiphactinus.

This jaw is huge.

This must have been
an immense fish.

Probably close to 14 feet long.

14-foot-long fish in Kansas.

Name me a living
14-foot-long fish.

Well, if you count the billon a marlin, maybe.

We're in Kansas, Chuck.

So a 14-foot-long fish
in Kansas?

Yeah, sure.

JOHNSON:
What is this ancient marine
predator doing

750 miles
from the nearest ocean?

Well, it turns out,

80 million years ago,
the ocean was here,

right on top of Kansas.

It was teeming with mighty
sea creatures

like Chuck and Barbara's
14-foot Xiphactinus.

But it wasn't just Kansas
that was covered in water.

About 130 million years ago,

the ocean began to invade
North America.

Water flooded in and formed
a massive inland sea

up to a thousand miles wide.

It split the continent
into two landmasses:

Laramidia in the west
and Appalachia in the east.

The big inland sea would have
huge consequences

for life on our continent,

especially
North America's dinosaurs.

Back in the Kaiparowits in Utah,

where scientists have discovered

an amazing new collection
of dinosaurs,

paleontologist Joe Sertich shows
me his latest find

from this extraordinary
dinosaur graveyard.

That's pretty clearlya horn.

SERTICH:
Yep.

Here you can see where
the eye would have been.

There's a large section
of the horn coming off.

There's the tip
of the horn there.

It's starting to look more and
more like a brand new species.

This is so Jurassic Park.

It is.

JOHNSON:
The new dinosaurs here
are remarkably different

from other dinosaurs that livedfarther north at the same time.

So what is it
with all this diversity?

From around a hundred million
years ago,

our continent was split down
the middle by the inland sea.

Over time, sea levels changed,
shifting the coastline

back and forth all the time.

And keeping the dinosaurs of
North America on their toes.

With their home turf
constantly changing,

groups of dinosaurs evolved
over time and adapted

to their local surroundings.

Joe and his colleagues
have collected

an amazing variety of dinosaurs
and fossil plants,

showing how different
environments

drove dinosaur diversity.

So what you're saying

is that these differentenvironments along the coastline

create different landscapes

for dinosaurs to evolve in.

Exactly.

SERTICH:
We suspect that these
different ecosystems

are driving dinosaur
diversification

as dinosaurs and other animalsadapt to their local conditions.

And that makes North Americaa dinosaur factory.

Exactly.

JOHNSON:
As a paleontologist,

it's really exciting to think
that 75 million years ago,

this land was full of dinosaurs
of every description.

They all lived along
this huge inland sea

that split America down themiddle and created a whole bunch

of different habitats.

But 70 million years ago,
something dramatic happened.

The great North American seaway
began to drain away.

So what happened to make this
enormous body of water

totally vanish?

To solve that mystery,

I've got to head east
from Utah to Colorado.

This place was also once covered
by the vast inland sea.

With a big sky overhead,
you can see for miles.

Ah, it's really great views
up here.

Three sixty.

But I didn't climb this hill
just for the view.

I'm on the hunt for some
strange-looking objects

that I'm hoping to find
right under my feet.

That's what I'm looking for,
but it's not a very good one.

These hollowed-out rocks are
clues that help explain

why North America's giant
inland sea disappeared.

Here's a pretty good one.

After a rain, the water pools
in them like this

and the birds come and bathe
in these things,

and the locals call these things
birdbaths,

but they're actually somethingmuch more interesting than that.

JOHNSON:
These rocks once contained
fossils of ancient shellfish

called ammonites.

You can pretty clearly see
the shape of the shell

if you start in the center here,

and the spiral goes all
the way out.

And in the middle, there wouldhave been a series of chambers.

The fleshy part of the animal
would have stuck out

of the shell here
and it would have looked

something like a squid
or an octopus.

For more than 40 million years,
North America's inland sea

was filled with giant ammonites
like these.

But it's one thing to find
marine fossils

in the flatlands of Kansas.

It's another to find them inthe mountains high above Denver.

The big question here is,
what's going on?

But I've got an altimeter here
and the altimeter says

that I'm 7,703 feet
above sea level.

That means that something took
marine creatures

and brought them to an elevation

that's more than a mile above
sea level.

It's the same thing

that made North America's
inland sea disappear.

And driving it all

is the constant motion
of the ground itself.

Because the surface of ourplanet is broken up into pieces

that slowly slide along a
conveyor belt of hot rock

miles beneath us
at about two inches a year.

Around 70 million years ago,

a piece of crust under the
Pacific Ocean was diving down

at the western edge
of North America.

We think that it then began toslide right under the continent,

making it rise, forcing it up
inch by inch

to create an icon of the
North American landscape...

the Rocky Mountains.

The birth of this majestic
mountain range

was the death of North America's
great inland sea.

As the Rockies began to rise,
the land under the Inland Sea

was forced up and
all of its waters drained

into what is now the Arctic
Ocean and the Gulf of Mexico.

This left the marine creatures
living in the Inland Sea

literally high and dry.

It's mind-boggling to think that
the bottom of the sea

could be found at the top
of a mountain range,

but here are all these fossils
that say that it's so.

The forces under the earth are
so slow, but so relentless.

Over millions of years,

they completely altered theshape and form of the continent

and changed the fates of the
millions of plants and animals

that were living there.

From the very beginning, rocksand life have been intertwined.

But this process doesn't always
move slowly.

And change doesn't always come
from below,

as our old friends the dinosaurs
were about to find out.

So I pack my bags
and head north...

to track down a 66-million-
year-old smoking gun.

Thanks so much.

These are the North Dakota
Badlands.

Thousands of square miles
of arid gullies and buttes.

I'm driving deep
into the badlands here,

on what is called the state
highway, but it's actually

a gravel road.

And right around us here is
what's called

the Hell Creek formation.

It's a 300-foot-thick layer of
rock that stretches

over four states,

and it's a spot that I just keepcoming back to again and again.

And here's a cow
I'm about to hit.

I just can'tet enough
of this place,

because hidden in these hills is
evidence of an earth-shaking,

life-changing event.

To find it, I'm going to have
to do a little digging.

I've actually got a couple ofpieces of fossil charcoal here,

and that's pretty common in
these layered rocks--

you find evidence
of the ancient world,

whether it's the mud at a bottom
of a lake,

the coal from a swamp,

or the charcoal
from an ancient forest fire.

And every layer used to be

the surface of the earth
at a certain point in time.

Now there's a stack
of these layers,

and I'm looking for one layer
in particular--

one very thin, one very special,
one very scary layer.

After a few minutes of digging,

I find the 66-million-year-old
layer I've been searching for.

There it is, right along here.

It's a little rusty orange
layer.

It doesn't look like much,
but this layer is Armageddon.

To show you why,
I need to get in closer.

What I'll do is just set upmy handy-dandy field microscope.

I'm looking at this layer
under the microscope

and what I'm seeing is that
it's actually composed

of little round ballsabout a millimeter in diameter.

And these things are what used
to be little glass beads.

So what you've got basically issome sort of geologic phenomenon

that's dropping beads of glass
onto an ancient landscape.

So what could have
happened here?

One way you get a layer of glass
beads on a landscape

is to have a violent event

that melts rock and blasts it
in the air.

As the molten rock flies through
the air,

it cools into glass and rains
down on the landscape

as glass beads.

If all we found in this layer
were glass beads,

the most likely
explanation might be

a massive volcanic eruption.

But there's something else
hidden within this layer

that changes the story...

tiny crystals
called shocked quartz.

Quartz is an extremely
common mineral.

You can find it
all over the planet.

But when it shows up
with these parallel lines

as shocked quartz,
that means it's been exposed

to huge amounts of energy...

Like you get
at nuclear test sites.

But when this layer of earth
was laid down,

there were no atomic bombs.

There was only one thing
that could have made

a big enough bang
to shock quartz.

About 66 million years ago,

an asteroid the size of Mount
Everest was headed for Earth.

It entered the atmosphere

at over 20 times the speed
of a rifle bullet

and exploded with more power
than a billion atomic bombs,

sending a superheated plume
of vaporized rock

shooting across North America

and over a hundred miles
up into space.

This cloud of doom carried
droplets of molten glass

and shocked quartz all the way
to where I found them

in North Dakota and beyond,

bringing death and destruction
to our planet.

But what effect did it have
on the dinosaurs?

For the last 30 yearsit's been pretty widely thought

that one of the main groupsof animals that were the victims

of this event
were the dinosaurs.

If this is the case,

it's useful to have some
real scientific data.

30 miles down the road is a guy
who can help me with this.

Tyler Lyson is a paleontologist

who's been digging up dinosaur
fossils in these badlands

for more than 20 years.

It's been a long time,buddy.

Yeah, how's it going?

Always good in dinosaur land.

What have you got going?

Have a look at this.

Here we have a thescelosaur.

JOHNSON:
Tyler and his crew have pulled
dozens of dinosaur skeletons

from these rocks,
among them big names

like triceratops
and
Tyrannosaurus rex.

All told, how many different
kinds of dinosaurs

have you found in this area?

Two dozen.

We've found allthe major players here.

Just happens to be oneof the best places in the world

to find dinosaurs.

It's a rich, rich area.

JOHNSON:
But where do we find
these dinosaurs?

Are they below the impact layer
or above?

Before the asteroid struck?

Or after?

So where is the asteroidimpact layer here?

It's right at the layer
of that boulder right there.

So what do you get below that?

LYSON:
Well, we have some
really big dinosaurs.

We have the big plant-eating
dinosaurs

like triceratops, edmontosaurus,
thescelosaurus.

And then the thing that ate
those dinosaurs, like
T. rex.

JOHNSON:
So above the asteroid
impact layer,

what do you get?

LYSON:
Well, we get a few turtles,
we get crocodiles, some birds,

a few lizards and fish.

You find any dinosaursat all above there?

No dinosaurs above
that black line right there.

JOHNSON:
So below is dinosaurs
and above is no dinosaurs.

Absolutely right.

JOHNSON:Nobody has ever found dinosaursabove the asteroid impact layer

in North America or anywhere
else on the planet.

To me, that's
pretty convincing evidence

that this catastrophic collision
wiped out the dinosaurs.

And they weren't the only
living things to suffer.

This amazing fossil leaf just
popped out of this rock.

Tap a little bit more,
expose it.

There's a leaf that hasn't seen
the sun for 66 million years.

You can even see holes
in the leaf

where cretaceous insects fed
on the leaf

when it was growing in a forest
that was full of dinosaurs.

And it's this world
that was terminated

by the impact of the asteroid.

We lost more than half
the species of plants

and more than half
the species of insects.

It was truly an ecosystem-wide
devastating event.

But even with all this globaldestruction, among the survivors

was one special group of animals
that managed to hang on:

the mammals.

It was little mammals not unlike
these chipmunks

that survived the asteroid
impact, and they survived

because they had small body
size, a large population size,

they could reproduce fast,
they lived in burrows.

They were almost pre-adapted
to survive an event

like the asteroid impact.

And once the dinosaurs were gone

they had the world
to themselves.

In the millions of years
that followed,

mammals evolved and changed,
spread and diversified.

They filled every available
niche on land, sea, and air

here in North America
and all over the planet.

But it's the evolution of one
particular group of mammals,

the primates, that's of special
importance to us.

But there's a huge mystery.

Today, except for some monkeys
in Central America,

the only primates native to ourcontinent are us: human beings.

If you want to see
other primates,

like gorillas, baboons,
and monkeys,

you have to visit a zoo.

Or come to a place like this:

the Duke University
Lemur Center.

Whoa!

Look how high
that thing is going.

It's an 80-acre site

dedicated to the study
and preservation of lemurs,

a group of primates
that evolved in Madagascar.

Here they come, there's a bunch
coming at me right now.

That one's eating
one peanut in each hand.

It's like he's eating
ice cream cones.

Wow, this is awesome to be
so close to these things.

Incredible how well they move
through the forest

and to actually see them
moving around the trees.

They'll go straight up
a tree 40 feet

and then jump probably 25,
30 feet between the trees.

Seeing these little guys leap
from tree to tree,

you quickly realize that almost
everything about primates

is perfectly adapted
to a tree-filled environment.

And that kind of makes
you wonder.

We've got plenty of forests
here in North America.

Why don't we have primates
like these lemurs

jumping through our trees?

Well, the fact is, we did.

And paleontologist Doug Boyer
can show us.

Ah, that's a nice one.

JOHNSON:
One example is now

a jumble of bones encased in ablock of sandstone from Wyoming.

This particular accumulation
of bones happens to be

about 48 million years old.

There's still a lot of rock
on it though.

Well, instead of extracting
every bone physically,

we can scan it.

JOHNSON:
As the scanner gets to work,
a faint image comes into view.

Now we can see somethingstarting to come through.

JOHNSON:
Oh, wow, look at that.

There's the elbow
coming into view.

It's so tantalizing.

You just see those...there's sort of shapes in there.

JOHNSON:
From the scan data,

Doug builds upa full 3-D image of the fossil.

It reveals an amazing feature.

We have some of the hand here.

Here's some of
the finger bones.

JOHNSON:
How long those fingers are!

They're really long.

BOYER:
This animal had
incredibly long fingers.

If we were to scale this animal
up to your size...

My fingers would be,like, that long.

Freakishly long fingers.

You'd have fingers that were
about nine inches long.

Wow.

JOHNSON:
Those long fingers,
perfect for grasping,

are a tell-tale sign
of a primate.

And thousands of early primate
specimens have been found

all over America.

These little guys were
about two feet long.

Like the lemurs,
they were great tree-climbers

and probably lived on fruit.

When you watch these guys moving
around the forest,

you realize what all these
adaptations are for:

the long fingers, the long toes,
the tail, the ability to jump.

When you look at the fossils,

it's the same features
preserved in the bones.

It doesn't take
an expert to realize

that those fossils belonged

to animals that were
like these animals

and lived and moved in forests.

So, how did all these
ancient primates get here?

Where did they come from?

56 million years ago,
a huge, fiery rift opened up

in what's now
the North Atlantic.

An event with dramatic
consequences

for North America
and our entire planet.

Volcanic eruptions poured huge
amounts of lava

for thousands of years.

Releasing colossal amounts
of greenhouse gases,

like carbon dioxide and methane.

Like a blanket
in the atmosphere,

they kept in the heat,
leading to an intense period

of global warming
that changed the vegetation

across North America.

The cool forests
covering the north

turned into dense
subtropical rainforests

stretching all the way
to Alaska.

These trees kept their leaves
all year round,

providing food and shelter
for primates

so they could make the leapfrom Asia across a land bridge,

a leafy highway
to North America.

They hung around for more
than 20 million years,

spreading all over
our continent.

But then temperatures
dropped sharply,

wiping out
the subtropical forests

and their leaping inhabitants.

For millions of years,

nearly all of North America
would remain primate-free.

Then, around 14,000 years ago,

almost a blink
in geological time,

a certain two-legged primate
made its entrance.

That primate, of course, was us,

and our arrival changed
everything.

The first humans to arrive
in America

found a land full
of untold riches.

They'd really have a whole new
world open in front of them.

They could move down the coast,
which was full of resources:

fish, whales, seals, deer.

And the coastline is like
an open pathway, a gateway

into a continent four billion
years in the making...

providing us with an enormous
geological bounty.

Gifts of the earth hidden
in the landscape--

gold, iron, oil, and more--

harnessed to build
the vast civilization

that surrounds us today.

For the first time

in the history of life
in North America,

here was a species that wouldnot just adapt to the landscape,

but transform it.

The investigation continues
online

MAN:
Ready for this?

10,000 years ago, our continent
was locked in ice.

So how did we get here?

JOHNSON:
It's hard to imagine
somebody crossing

even one ice field like this.

What challenges did we face?

And how do we turn the rocks
of our homeland into riches?

Oh man, this thing
is phenomenal.

Making North America,
next time on

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NOVA is provided by the following...

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