Original subtitles

[gentle music]

NARRATOR: The story of life on Earth...

[chirps]

[roaring]

...has been marked by a series

of catastrophic extinction events.

Natural disasters which have threatened to wipe out

many of the creatures that call our planet home.

[snarling]

But with each brush with death,

life has come back even stronger.

[dramatic music]

One of the planet’s first great extinctions

took place 444 million years ago.

[majestic music]

In the shallow seas, life had established an exotic foothold.

♪

But then, suddenly,

the climate cooled,

sea levels plummeted,

and 85% of all life died out.

♪

Eventually, the seas rose again...

♪

...the survivors rebuilt their world...

♪

...and some discovered a whole new one.

[theme music]

[dramatic music]

NARRATOR: This is Earth, 444 million years ago.

This is a world that will not see the first dinosaur

for another 200 million years.

The continents are mostly in the southern hemisphere,

and all of them are barren wildernesses,

devoid of all but microscopic life.

No roars, no barking,

not even a chirp sounds across the empty landscape.

[wind gusts howl]

Carbon dioxide is a staggering 14 times higher

in the atmosphere than it is today,

and the days are three hours shorter.

[mysterious music]

It is a truly alien world,

and yet, there is a place where life is thriving.

[gentle music]

Hidden in the warm, shallow sea,

lives a magical world,

[waves crash]

♪

Thousands of miles of spectacular reefs.

These dazzling corals are home to newly-evolved

complex creatures like starfish, and horseshoe crabs.

Bug-eyed trilobites swim upside down,

sifting the water for food.

♪

Yet one animal,

whose descendants will one day fill the seas,

and a forerunner of every bird, mammal,

and reptile on Earth,

is surprisingly hard to find.

[water laps gently]

[whimsical music]

This guy, a fish.

These are Sacabambaspis,

one of the first animals on Earth to evolve a backbone.

These two young males are here for lunch.

♪

The reefs are full of things to eat,

but most creatures here have hard shells,

and all these young fellas can do is suck.

♪

[dramatic music]

Their search for food takes them into a field of sea lilies.

These graceful lilies aren’t actually plants,

they’re animals, filter feeders,

that open their arms to catch plankton in the water.

[majestic music]

Finally, one of our little guys finds a snack.

He doesn’t have jaws or teeth,

so he has to get his head right inside.

[whimsical music]

And now, he’s stuck.

♪

It is just not his day.

[music turns suspenseful]

His awkward jam has caught the eye

of some squid-like predators.

♪

They don’t know what this strange object is,

just that it’s worth fighting over.

[thuds]

♪

Our hungry little Sacabambaspis makes a break for it,

and finds a place to hide.

This cave should keep him safe.

[ominous music]

What he doesn’t know is that he has company.

[ominous music swells]

Hiding in the shadows is the reef’s top predator.

NARRATOR: 444 million years ago,

the land is empty,

but these shallow seas are filled with coral reefs.

[dramatic music]

It is the only place on the whole planet

that teems with complex life.

[ominous music]

Our little fish has taken refuge in a cave,

only to discover he’s not alone.

A giant sea scorpion.

This reef’s apex predator.

But this scorpion isn’t hunting in this cave.

She’s here to molt.

She can only get bigger by shedding

one armored skin and growing another,

but this makes her soft and vulnerable

for a few hours.

[gentle music]

Sometimes, even apex predators have to hide.

Looks like it’s this guy’s lucky day.

♪

These endless shallow seas have proved

the perfect nursery for early life,

but something is happening on land

that is about to spoil this prehistoric paradise.

Across the empty landscapes,

the absence of vegetation means wind and water

tear at its surface.

[waves splashing]

[thunder rumbling]

Massive dust storms,

and rivers laden with sediment

are dumping vast quantities of materials into the sea.

[majestic music]

This onslaught of minerals is feeding marine algae

on an explosive scale,

generating enormous blooms across the oceans.

These algae blooms, in turn,

absorb carbon dioxide from the atmosphere,

and the levels of this greenhouse gas

are now plummeting.

♪

Earth has reached a tipping point.

It’s cooling down fast.

Even the warmest seas will soon feel the change.

[waves crashing]

Back at the reef, our little guy

has returned to the sea lily field.

[gentle music]

This time he is here looking for something else.

His bright red tail is a sign he’s ready to mate,

and he’s searching for the right spot to build a nest,

so he can attract a female.

♪

At last, a clearing amongst the lilies.

Except all these other guys had the same idea.

The competition is already fighting over the best spots.

[intriguing music]

A female.

Her silvery stomach signaling she’s ready to lay her eggs.

So now, it’s showtime.

♪

The males start to dance.

They’re all trying to woo her, to lay her eggs in their nest.

♪

She’s chosen.

Our little guy is late to the party.

To stand a chance, he needs to find his own space.

♪

At last, an empty spot.

[music swells]

Our little fish can only watch as a larger male settles in.

[ominous music]

A predatory bristle worm.

But it’s bitten off more than it can chew.

No wonder that bit of sand wasn’t taken.

[gentle music]

These coastlines might look tranquil.

[waves crashing]

But twice a day, beneath the water,

it’s a different story.

[waves crashing]

The water is so shallow that when the tides change,

they produce massive rip currents.

[water roaring]

The nesting males hunker down, protected by the sea lilies.

These early fish are not strong swimmers.

So they stick close to the seafloor.

[water roaring]

[tense music]

The giant sea scorpion.

Now that she’s finished her molting,

she’s bigger and hungrier than ever.

[ominous music swells]

But she’s after a bigger meal.

The bristle worm.

But in the chaos,

our hapless little fish is thrown up into the riptide.

[dramatic music]

The current up here is too strong.

[dramatic music swells]

It drags him away over the reef.

Soon, he is swept out to sea.

[waves roar]

By the time the tide releases him,

he is over a mile from the reef.

Exhausted and alone, it looks like his luck has run out.

Even worse, here be monsters.

[majestic music]

NARRATOR: For millions of years,

Earth has had high levels of carbon dioxide,

which have heated the atmosphere, and warmed the seas.

These shallow waters have been perfect

for complex life to evolve.

But now, they are cooling fast.

♪

This crisis has not reached our young fish yet,

but he is still in trouble.

[dramatic music]

He has been dragged off the reef by strong tides.

Now, he is lost in the open ocean,

a long, long way from home.

[somber music]

The waters here are an unfamiliar deep green.

♪

He’s on the edge of a vast algae bloom,

one of many that are drawing carbon dioxide

out of the atmosphere, and cooling the planet.

The consequences of this climate shift are extreme.

[tense music]

At this time, most of the world’s land masses

sit over the South Pole,

and as temperatures plummet,

a giant ice cap is formed.

All this ice is reflecting the sunlight,

making the planet cool even faster.

Even for the warmer seas further north, change is coming.

[gentle music]

By sunset, our little fish

still hasn’t found his way back to the reef.

He will not last much longer.

Then, in the middle of nowhere,

he discovers something he can rest on,

and there’s food on it.

Things are looking up.

Clustered with hundreds of clam-like Brachiopods,

it looks just like part of a reef.

♪

[music turns ominous]

A giant orthocone.

At 30 feet long,

this is the largest creature on the planet,

the ocean’s top predator.

It has 10 long tentacles that feed a powerful beak-like mouth.

Fortunately, our fish is too small to be in any danger.

Sometimes, it pays to be tiny.

Orthocones are normally solitary,

but now is a time of gathering.

Tonight, there is a supermoon.

[reverent music]

This long ago in prehistory,

the moon is closer to the Earth,

and larger in the sky.

It has a huge influence on the rhythms of life in the ocean.

On this special night,

the moon signals the start of one of the sea’s weirdest

and most spectacular events,

a mass mating.

♪

Our lost fish decides to take a chance, and hitches a ride.

Luck is with him again.

The orthocones are heading into shallower waters to mate.

They’re taking our little adventurer back to the reef.

♪

Under the light of the supermoon,

the reef is putting on its biggest annual spectacle,

as most of the animals prepare to mate.

But is it all too late for the little fish?

[waves crashing]

NARRATOR: 444 million years before modern humans evolve,

most creatures on Earth do not live by the seasons.

[reverent music]

Instead, it is the moon and tides

that have the most profound effect on the rhythms of life.

♪

Tonight, there is a supermoon,

and it is a time of mating for all creatures.

♪

All along the reef,

every animal triggers a glowing trail of phosphorescence

as their motion disturbs algae in the water.

♪

Our lucky little Sacabambaspis is right back where he started.

There’s no place like home.

♪

It’s mating time for many.

The corals and sea lilies are spawning.

♪

Generating clouds of eggs and sperm

that cloak the entire reef.

♪

Our eager youngster heads back to his mating site.

It looks like he’s too late.

But after all he’s been through, he isn’t giving up yet.

He gets to work making a nest.

Just beyond the reef,

hundreds of orthocones have now gathered.

Normally, these giants would see another of their kind

as a threat, and attack.

But not tonight.

The males must woo a mate,

and they do this with a spectacular light show.

[majestic music]

He lights up with luminescent patches on his skin.

Then he spreads his tentacles wide,

and begins a gentle, mesmerizing dance.

♪

She accepts.

♪

Mating is brief.

He doesn’t want to push his luck.

[gentle music]

Our plucky Sacabambaspis seems to have missed out.

Then, a solitary female appears.

This is his moment, his last chance to dance.

[energetic music]

♪

With no other challengers to distract her,

she lays her eggs.

And then our young male fertilizes them.

Mission accomplished.

[waves lap gently]

All across the reef,

millions of animals have begun their next generation.

But daybreak reveals a sinister arrival.

[tense music]

A warning from the frozen south.

An iceberg has drifted all the way up from the polar ice cap.

Life on this reef is about to change forever.

[waves crashing]

NARRATOR: As temperatures drop across the planet,

the oceans are cooling down fast,

and a huge ice cap is growing over the south pole.

[ice creaking]

Icebergs are breaking off,

and one has made it all the way to the tropics.

[waves crashing]

Life here is living on borrowed time.

[gentle music]

A female orthocone is looking for somewhere to lay her eggs.

♪

She’s not used to these shallow waters,

and is a little unsteady on her tentacles.

[upbeat music]

She’s also being watched.

[music turns ominous]

A predatory sea scorpion has picked up the scent

of her new eggs.

♪

They’d make a tasty meal.

♪

But this...

is the wrong mother to mess with.

[gentle music]

Orthocones do not abandon their eggs.

Standing guard, she will not eat

or leave this spot for six months.

Which means, by the time they hatch,

she will have died.

A mother’s ultimate sacrifice.

[somber music]

Back in the clearing,

the Sacabambaspis adults have all moved on.

[gentle music]

But under the sand,

lie their abandoned, translucent eggs.

[waves crashing]

As the days pass,

the iceberg that broke off thousands of miles away

floats ever closer to the reef.

And the freezing cold fresh water cascading down its sides

pours directly into the shallows.

[dramatic music]

For these creatures used to warm saltwater,

it means death.

Those that can move try to escape,

like these trilobites.

♪

Eventually, the cold water hits the Sacabambaspis nesting site.

They hatch at the worst moment.

But at least these newborns are mobile.

♪

The damage caused by this iceberg is only local.

The bigger threat is that the entire planet is cooling.

As the polar ice cap in the south grows,

it captures water as ice.

[wind gusts howl]

Eventually, reaching eight times the size of today’s Antarctica,

it locks away so much water that global sea levels

drop by 300 feet.

♪

Thousands of miles of vibrant and colorful reefs

are left high and dry,

deprived of the one and only habitat

in which it has evolved to thrive.

85% percent of all the life on Earth

is driven to extinction.

♪

[gentle music]

Ultimately, it is the Earth itself that comes to life’s aid.

Over hundreds of thousands of years,

volcanic activity from beneath the ice

spews out carbon dioxide, warming the atmosphere.

The giant ice cap melts.

[water splashes]

and sea levels rise as fast as they fell.

From their scattered sanctuaries,

survivors begin to recolonize,

and new versions of the old animal groups return.

♪

♪

15 million years later,

life roars back.

But there is a crucial difference.

[waves roar]

For the first time,

creatures are leaving the water for the land.

[dramatic music]

NARRATOR: It is 15 million years

since the oceans suddenly cooled.

Volcanic activity warmed the planet and its oceans again,

but the temperature shock caused a catastrophic mass extinction.

However, enough life survived to recolonize,

and now, at last, the shallow seas

are teeming with exotic creatures again.

[gentle music]

Many remain unchanged.

But one group has been through a revolution,

the descendant of our little Sacabambaspis.

Fish.

There are now many, many more of them.

♪

These new fish have jaws and teeth.

Unlike the timid Sacabambaspis,

they are strong swimmers,

and are the fastest predators in the sea.

The scorpion is now their prey.

♪

But these scorpions have a trick up their sleeves,

and there is still a place where they can rule.

Scorpions are among the first complex lifeforms

to leave the sea behind, and crawl up onto land.

[majestic music]

Or at least, the first predators.

♪

Up here, there’s new prey to hunt.

An array of hard-shelled animals have followed plants onto land.

And animals aren’t the only ones thriving.

Both plants and fungi have started

to break down the rock,

creating soil,

[reverent music]

towering over it all.

Giant fungi, called Prototaxites,

the largest living things on the planet,

forming Earth’s first forests.

♪

Plant growth has raised oxygen levels in the atmosphere.

[thunder booms]

High enough to fuel fire.

In fact, the first forest fire is a sign of life’s success.

[thunder booms]

[fire crackles]

It is the start of a journey

that will take living things to every habitat on Earth.

[gentle music]

Today, one of the most challenging habitats for life

remains the coasts.

Every day, they change with the tides.

Every year, they grow or shrink from erosion.

And on a much longer timescale,

they are drowned,

or left high and dry by changing sea levels.

♪

Since the last ice age,

sea levels have risen 300 feet.

Around the world,

low-lying coastal plains were replaced by shallow seas.

In Australia, this proved an ideal habitat for coral.

♪

We now call it the Great Barrier Reef.

♪

Life has evolved to cope with changing sea levels.

For humans, the story is different.

During the short period of recorded history,

sea levels have been quite stable.

Vast cities have spread along our coasts,

some even below sea level.

[majestic music]

But now, because of global warming, that is changing.

Sea levels are predicted to rise

by around three feet by the end of the century.

We can build barriers against storms.

[water roaring]

But we cannot protect all cities

from the relentless power of rising oceans.

However, we are learning from nature.

♪

In some coastal cities,

rather than fighting the threat,

they aim to let the water in, and manage it.

They are taking a strategic approach to the future.

[gentle music]

Life has shown us the way.

To survive, we must adapt.

♪

♪ I see trees of green ♪

♪ Red roses too ♪

♪ I watch them bloom for me and you ♪

♪ And I think to myself ♪

♪ what a wonderful world ♪

♪ Yes, I think to myself ♪

♪ what a wonderful world ♪