Original subtitles

NARRATOR: They're dazzling.

Priceless.

At times, even glowing.

ROBERT HAZEN: How can one not fall in love with rocks and minerals?

I mean, the colors, the shapes...

NARRATOR: And they're the building blocks of modern civilization.

HAZEN: We wouldn't have televisions, we wouldn't have automobiles,

we wouldn't have buildings

without the mineral riches that we have.

NARRATOR: But could rocks and minerals

also solve the greatest mystery of all time--

the origin of life?

HAZEN: The rocks we pick up tell a story:

that life couldn't have occurred without rocks.

NARRATOR: Could cold, lifeless stone

hold the key to every living thing on Earth?

From Australia to Morocco,

NOVA goes around the world and back in time

to investigate the origin and evolution of life.

You look at a rock and you think, "Ah well, nothing,"

but this holds the signature of life.

NARRATOR: From its first spark...

JEFF BADA: People were saying they made Frankenstein in a test tube.

NARRATOR: ...to the survival of the fittest.

These were immense creatures--

sharks that may have been 50 or 60 feet.

NARRATOR: Was it the secret link between rocks and life

that made the difference?

"Life's Rocky Start," right now on NOVA.

Major fuNARRATOR: NOVA is The ancient market of Marrakech,

a chaotic, colorful gathering place

teeming with life for thousands of years.

The perfect place to ask, how did this exotic, beautiful,

and sometimes bizarre thing called life begin?

How did Earth go from a lifeless, molten rock

to a living planet

full of diverse and spectacular creatures?

It's a question that has long perplexed scientists.

Now Robert Hazen, a geologist, is trying to show

we are missing an essential ingredient

in the recipe for life...

HAZEN: Look at that vein of calcite.

NARRATOR: Rocks.

HAZEN: Nothing seems more lifeless than a rock.

It's inanimate, it's the antithesis of a living thing.

But we are beginning to realize that rocks played

an absolutely fundamental role in the origin of life.

Aw, yeah.

NARRATOR: Hazen is out to expose a secret relationship

between rocks and life that helped drive

both the origin of life

and its evolution into complex creatures.

HAZEN: This is a very new set of understandings

and the more we look, the more we see

that life depends on rocks, rocks depend on life

and this has been going on for four billion years.

NARRATOR: As a geologist, it's no surprise that Hazen is searching

for answers written in stone.

But is he right?

Are rocks the missing spark of life?

The history of Earth is unimaginably long.

If it were sped up to the equivalent of a single day,

all of humankind from the earliest skeletons...

(phone ringing)

...to the invention of the iPhone

would have occurred in only the last four seconds.

Dinosaurs were still roaming Earth

about 20 minutes before that.

But the creation of our planet

occurred more than 23 hours earlier--

two cycles on this clock-- or 4.5 billion years ago.

Comprehending Earth's vast history is a formidable task.

HAZEN: There's four and a half billion years of change.

But you can divide it into half a dozen ways

of describing Earth through time.

NARRATOR: Bob Hazen has come up with another way to visualize

Earth's long history that reveals

this special relationship between rocks and life.

He has divided it into six stages,

each represented by a different color.

To understand how we ended up with green Earth--

the planet we now know--

requires us to turn the clock back,

to before there was any life at all.

Stage one was the creation of black Earth.

(indistinct chatter)

Back in Morocco,

Hazen and Adam Aronson, a meteorite expert,

seek out a small rock from the beginning of our cosmos.

Wow, look at this pile here.

NARRATOR: These are meteorites, rocks that have fallen from space.

This is Tamdackht.

This is the one that fell 20 kilometers

up the road from here.

People saw it fall.

NARRATOR: A recent meteorite fall in Siberia was captured in videos

that have shown up on YouTube.

Other space rocks have ended up for sale here in Morocco.

So you'd buy this without doing tests?

I would drop the cash right now

if he would give me a good price.

(speaking Arabic)

NARRATOR: Meteorites here can sell for tens of thousands of dollars.

That may seem a steep price for a lump of rock,

but these are some of the very oldest objects

in our solar system.

HAZEN: This is the oldest object you could ever hold in your hand.

It's 4.6 billion years old

and it was formed before earth formed.

This is the very first solid material,

the very first rock in our solar system

and these came together to build all the planets.

NARRATOR: Our Earth was created out of the rocks and dust

present at the start of our solar system.

Over time, small fragments of orbiting rock collided,

coming together into the planets circling the sun.

At first, Earth was molten

with temperatures in the thousands of degrees.

But in the cold vacuum of space

this hot rock began to cool and change.

Nothing, not a speck of dust, is believed to have survived

from the period of black Earth.

It was a hellishly unpleasant time.

Volcanoes spewed hot lava from deep inside the planet.

When it cooled,

it covered Earth with its first rock, called basalt.

And it was black.

It seems like a desolate landscape.

But some ingredients that life will need

are already here in these rocks.

Look inside and you begin to understand how intriguing

even an ordinary rock is.

HAZEN: Every rock, you slice it open, you look inside,

there's something special.

NARRATOR: Rocks are made up mostly of minerals, which are crystals

like quartz or diamonds.

Looking through a microscope at super-thin slices of a rock

lets you see its mineral composition.

This is the rock peridotite, made up of small crystals

including olivine and pyroxene.

Even a simple black basalt rock spewed from a volcano

becomes a patchwork of colorful minerals.

It's sort of like a fruitcake.

You know, you slice it open, there's nuts,

and there is dried fruit, and maybe some lemon peel.

It's made of lots of little things.

And it's not until you slice into that fruitcake

that you see all the stuff inside that makes it special.

NARRATOR: What makes them special is not only their beauty.

Minerals have remarkable chemical and physical properties

and are a source of many of the elements--

nature's building blocks.

That is why they're essential in our modern world

to make everything from skyscrapers taller

to mobile phones smaller.

Extract the element molybdenum from the mineral molybdenite

to make steel harder,

or add a pinch of cobalt

and your iPhone battery will last longer.

HAZEN: Minerals are the fundamental building block of societies.

We wouldn't have televisions, we wouldn't have automobiles,

we wouldn't have buildings

without the mineral riches that we have.

NARRATOR: So were the remarkable chemical properties of minerals

also key in creating life?

If so, Earth would need more than it started with.

It's estimated that the meteorites that formed Earth

had only about 250 minerals,

sort of a chemical starter kit containing many of the elements.

Then in the intense heat and pressures

in the creation of our planet, new minerals began to form.

This changed the appearance of our Earth from black to gray.

Yosemite National Park is a relatively new piece of Earth.

But the kind of rock that makes up these dramatic cliffs

goes back much further.

These huge walls are granite,

containing minerals like quartz and feldspar.

Granite became the foundation of our continents,

leading Earth into the gray period.

At this point, Earth is still a long way

from the glorious diversity of plants and animals

that makes Yosemite so picturesque.

But the stage is set

for the next character in our planet's story:

water, which will turn Earth blue.

Water plays a central role in every model

for the origin of life.

That's because water is such a great solvent.

All these different kinds of molecules

can be floating around the water

and then they have the potential to interact together.

The starting point is the water.

NARRATOR: So when did Earth cool enough to have liquid water,

this element key to life?

HAZEN: One of the biggest unknowns in this whole idea

of going from black to gray to a blue water-covered Earth

is how quickly it happened.

The timing was a big mystery.

NARRATOR: The Pilbara in Western Australia

is one of the oldest places on Earth,

and so one of the best places to solve the mystery

of the planet's first oceans.

Hazen joins an all-star team of geologists

including Martin Van Kranendonk,

from the University of New South Wales

and John Valley of the University of Wisconsin.

Valley is collecting rocks that could hold clues

to when water first appeared.

We can get zircons and other minerals

that date all the way back to 4.4 billion years old.

Hopefully.

NARRATOR: Some rocks here contain sand-sized grains

that weathered from even older rocks.

One in a million-- literally-- is a crystal called zircon,

one of the longest-lasting materials in nature.

Zircon is a popular gemstone,

but the microscopic zircon found here

is even more precious.

HAZEN: Zircon crystals are especially amazing.

Gemstone zircons of course are valued,

but these tiny ones that geologists value

are microscopic.

They make a lousy ring, but they tell an incredible story.

NARRATOR: To tell that story,

John Valley must first find the tiny crystals--

the ultimate needle in a haystack.

VALLEY: If you want to find a needle in a haystack,

the first thing you do is you burn down the haystack.

Then you'd sift through the ash to look for the needle.

NARRATOR: Rocks are pulverized into sand-sized grains

and sorted by weight in a machine

developed to pan for gold.

The gold that Valley is looking for are heavy zircon crystals,

which get channeled into different tracks.

Then, grain by grain, with a very steady hand,

thousands of small crystals are sorted and analyzed.

The chemical structure of a zircon crystal

holds evidence of both the environment

and the age when it formed.

Some of these tiny crystals go very far back,

just over 100 million years after Earth formed.

They are the oldest pieces of Earth ever discovered,

so they could shed light on what our young planet looked like.

VALLEY (laughing): It's totally amazing to me.

To hold this grain of sand in the palm of your hand

is literally to see back through time.

It is a time machine.

NARRATOR: Valley expected these crystal time machines

would confirm the long-held view that the young Earth

was covered in molten lava,

still cooling after its violent formation.

I think the zircon on the left looks very promising.

NARRATOR: So what he discovered was shocking

because this type of zircon, created 4.3 billion years ago,

could only have formed in the presence of liquid water.

But how could there be water

if Earth was still hot and hell-like?

VALLEY: The implications were that the early Earth had water.

It was cooler and it was wet.

It's starting to look very much more familiar.

NARRATOR: And if water is a key starting point for life,

could there be life that early, too?

VALLEY: The science of the zircon is telling us that the Earth

for a very, very long time was a habitable environment.

Not necessarily that there was life then.

We don't know that yet.

But there's no reason why there couldn't have been life

as early as 4.3 billion years ago.

NARRATOR: So if life were possible that early, it begs the question,

how did life begin?

In 1871, Charles Darwin

speculated in a letter to a friend

th warm little pond might be life's birthplace.

A warm soup of chemicals bathed by energy from the sun

would have been, well, comfortable for molecules

to come together in new ways and create life.

Darwin was way, way ahead of his time.

A nice little warm soup is going to get you a long way.

NARRATOR: Jeff Bada of the Scripps Institution of Oceanography

in San Diego, has spent his career

working to understand the early Earth's soup of chemicals.

He began under the direction of perhaps

the most famous scientist in origin of life research--

Stanley Miller.

HAZEN: There are in the history of science turning points

where we suddenly see the history of Earth

and life differently.

In the early 1950s, Stanley Miller,

the eager graduate student, and Harold Urey,

the Nobel Prize winning mentor at the University of Chicago,

conducted this astonishing experiment

where they made an early Earth environment.

BADA: It looks like this sort of a Frankenstein-type apparatus.

But actually, it's a very carefully thought out design.

NARRATOR: Bada sets up a modern-day test of the 1950s experiment

on Miller's original lab equipment.

BADA: One flask contains water.

That's to simulate the ocean.

The other flask has just got the gases in it.

So this is the atmosphere.

(gas hissing)

NARRATOR: Just as it does in nature,

water from the ocean evaporates and rises into the atmosphere,

where it condenses and returns to the ocean.

Miller simulated what he believed to be the atmosphere

of early Earth with different gases like ammonia and methane.

Then, he added a spark of genius.

(electricity humming)

BADA: Miller and Urey decided to use a spark to simulate lightning

because that's such a ubiquitous process

in the atmosphere of the earth.

HAZEN: That was the real inspiration,

these little electric sparks

they acted like simulated lightning.

NARRATOR: The energy from the spark of lightning

breaks down the gas and water molecules

so they can undergo further chemical reactions.

HAZEN: To their astonishment, when they turned this apparatus on

after only a couple of days you started seeing

this pink color developing.

And then a few more days, black, oily goo

is forming around the electrodes.

NARRATOR: The electrodes get covered with new substances,

organic compounds usually associated with life.

And it wasn't just any organic compound,

it was amino acids that make proteins.

The ingredients for life.

NARRATOR: Amino acids are the building blocks of life.

They form proteins,

which are the key component of muscles and other tissues.

People thought, "Aha!

This is a key step in the origin of life."

And you really believe that you can bring life to the dead?

That body is not dead.

It has never lived.

I created it.

NARRATOR: The experiment raised the fear that a Frankenstein creation,

like in this classic film, was just around the corner.

It's moving.

BADA: People were saying they made Frankenstein in a test tube.

It's alive!

Now I know what it feels like to be God!

NARRATOR: Had Miller and Urey cooked up life in a test tube?

BADA: Many of the news headlines were saying,

"Life created in the laboratory!"

"Life created in a test tube!"

Well, of course that was wrong.

The real news was he'd made these compounds

that are part of life.

NARRATOR: By creating amino acids, the Miller-Urey experiment

seemed to confirm that Darwin was right--

life must have begun in a shallow pond.

But then, 24 years later, a shocking discovery

radically challenged that idea.

On the dark ocean floor,

more than a mile below the surface,

explorers found hot, mineral-rich hydrothermal vents,

like underwater volcanoes.

Temperatures reached more than 600 degrees,

and yet here life was thriving, not off the sun's energy,

but through chemical energy from the vents.

No one realized that life could thrive without sunlight.

Here you have this extreme temperature

and this extreme pressure,

and so you have to shift your perceptions

and realize that just because it's extreme to us

doesn't mean it's extreme to those microbes.

NARRATOR: Instead of the warm shallow pond,

could this dark and unlikely environment be where life began?

To answer that, Hazen decided to try creating

life's building blocks in the conditions of a deep sea vent.

HAZEN: My first thought was gee,

why don't we do a Miller-Urey experiment,

but do it at high temperature, high pressures?

NARRATOR: Hazen's laboratory

is at the Carnegie Institution for Science,

which is famous for experiments that simulate

the intense pressures deep inside Earth

with powerful tools called pressure bombs.

They're called bombs for a reason--

because things can explode.

(loud explosion)

NARRATOR: Hazen and his colleagues adapted these pressure bombs

to model the environment of the deep sea vents

in a small gold tube.

What they discovered came as a surprise.

Nothing happened.

HAZEN: You can take basic gases--

nitrogen, CO2, maybe some sulfur compounds.

You can mix those, you can put them in a gold tube,

you can heat them up.

You don't get much that's very interesting.

NARRATOR: Simply squeezing and heating the ingredients had little effect.

Hazen was missing the spark,

like in the Miller-Urey experiment,

the thing that kickstarts the chemistry.

HAZEN: So we said, "What's going on, what's different?"

Well, look at the natural environment,

there's all these rocks and minerals.

Let's try putting some rocks and minerals in.

NARRATOR: They recreate the early Earth cocktail,

but this time grind in powder from rocks and minerals.

But will Hazen's beloved rocks do the trick?

(air hissing)

They run the experiment again.

And this time the atoms reform into new organic molecules--

including amino acids.

HAZEN: As soon as you put powdered rocks and minerals

into the gold capsules,

then all sorts of really amazing things started happening.

You made organic molecules,

they became more stable, they lasted longer,

and it really pointed us in the direction of saying,

"Aha, this has got to be part of the story."

NARRATOR: While scientists still argue

if life began in shallow ponds or deep sea vents,

both sides wonder,

what part of the story did rocks and minerals play?

One possible answer may be found in London,

in the powerful properties of mud.

Most people will be familiar with the material.

It's very gungy.

That's perhaps a British word

that refers to something which is soft

and unpleasant, generally.

NARRATOR: Peter Coveney of University College London

is busy playing in mud-- at a very sophisticated level.

He has created powerful computer simulations

that can track the precise movement

of up to ten million atoms.

Mud can contain clay,

which is made up of some of Earth's most common minerals.

What makes it so gungy

and perhaps essential in the origin of life

can be seen deep in its atomic makeup.

COVENEY: You can see here the basic structure of any clay.

It's comprised of a large number of stacked sheets

like a deck of cards.

NARRATOR: Sheets of clay have spaces between them

that fill up with water and other molecules.

These extensive surface areas can help create

more complex molecules, potentially even RNA,

an essential part of life's genetic code.

COVENEY: One of the most challenging questions

in the origin of life

is how we get from the simple building blocks

to the complicated structures

we know are fundamental to living systems.

Clays provide a clear mechanism for achieving that.

NARRATOR: These simulations show that the secret to clay

lies in its surfaces.

The surfaces of these minerals are incredible.

They do all sorts of chemical tricks.

NARRATOR: Hazen says minerals, like clays,

illustrate a fascinating aspect of chemistry,

because the surface where reactions take place

can be as important as the ingredients themselves.

The most exquisite chemistry occurs at surfaces.

Your body, your cells are almost entirely surfaces

on which chemistry takes place.

So when we think about the origin of life,

the minerals sort of replace surfaces you have in your body

that do that chemical work.

NARRATOR: We are finally beginning to understand the secret role

minerals could have played in life's origin.

They provided some of the ingredients and surfaces

where important chemical reactions take place.

So when in Hazen's color phases did all this happen?

One of the best places

to figure that out is back in Australia,

where Hazen and team are now searching for signs

of Earth's earliest life.

HAZEN: I can't believe these rocks

are three and a half billion years old.

They look like they formed last week.

NARRATOR: Martin Van Kranendonk leads the team

to a very unusual rock formation.

You get your eye casting up, you see them,

all wrinkly, laminated, black.

Yeah!

VAN KRANENDONK: And then if you look a bit further back,

you see a very large domical structure.

HAZEN: There's no obvious way

that a chemical or physical process would form that.

VAN KRANENDONK: Exactly.

NARRATOR: These strange shapes

are fossilized remnants of life called stromatolites,

beautifully preserved in these ancient rocks.

VAN KRANENDONK: This is an amazing spot.

We're actually looking down on the surface

of the ancient Earth here.

This was the seafloor

3.4 billion years ago, and I can see it in action.

It's like a snap frozen instant of time.

NARRATOR: But billions of years have taken their toll.

To really understand stromatolites,

we have to go nearly 800 miles away.

David Flannery, a geologist, has come to Shark Bay

in search of their very distant descendants.

Just below the surface, he finds a series of round, black mounds:

living stromatolites.

FLANNERY: Modern environments like these,

they're very rare, but they are really the key

to interpreting what we see in the very early fossil record.

Without environments like these, we wouldn't know

how stromatolites were built.

NARRATOR: Stromatolites are something like coral,

a hard mineral structure that has been built layer by layer.

A closer look reveals the builders.

Microbes-- single-celled life.

FLANNERY: The living part of a stromatolite

is only the surface where the living microbial mat

is building up the structure layer by layer

at less than a millimeter per year.

NARRATOR: The top layer of these stromatolites is alive,

with microbes that perform a remarkable trick.

They capture minerals and sand in the water

and biologically cement them layer by layer

into the solid mounds.

The results can be seen in Shark Bay today

and in the ancient fossils.

Yeah, let me introduce you to this outcrop.

It's just spectacular to be able to see this.

NARRATOR: And this outcrop is unique.

Van Kranendonk has dated this stromatolite

to 3.5 billion years ago.

This is the very oldest fossil of life on Earth.

HAZEN: We all want to know where we come from,

where life originated, how long ago, in what form,

and this is the oldest direct evidence we have

for life on Earth.

NARRATOR: But while stromatolites

are the earliest fossil of life we've found,

that does not make them the very first living thing.

In fact, Van Kranendonk thinks

that by the time stromatolites appeared,

life's party was already in full swing.

There are whole communities and colonies

that are building fantastically complex structures,

so we've actually come in pretty late to the game.

There is a lot that's gone on before us to get to this stage,

and it's this complexity that tells us that life

probably originated on Earth very early.

NARRATOR: So if these very early fossils

are too complex to be the oldest form of life,

is it possible to find something earlier?

That is what Ruth Blake, a geologist at Yale University,

is trying to figure out

by turning to the geological equivalent

of a crime scene investigation.

BLAKE: The crime has been committed.

The criminal is gone,

but they've left behind some indicator

because they've changed their environment.

NARRATOR: Blake is analyzing some of the oldest rocks on Earth,

like this ground-up one from Greenland

that formed at the bottom of an ocean.

She is looking for a chemical signature of life

left by microbes, including bacteria.

What we start with is our ocean trapped in a rock,

and our bio-signature is somewhere in here.

We have to get it out.

NARRATOR: In the lab, Blake and her team

dissolve these rocks and extract molecules

that are the chemical signature left behind by ancient microbes.

All life, like these microbes,

consumes nutrients to produce energy.

The leftovers carry the chemical footprint of life.

Even today, we humans leave behind chemical footprints.

BLAKE: When we breathe, for example, we're taking in oxygen

and we're exhaling CO2 and water vapor.

That water vapor interacts with your environment.

NARRATOR: Amazingly, rocks from 3.5 billion years ago,

at the time of the stromatolites in Australia,

also carry a strong chemical footprint of life.

But when Blake analyzes the Greenland rocks

from 300 million years earlier,

she makes a tantalizing discovery.

BLAKE: As far back as 3.5 billion years,

we see a strong biological signature.

And the older rocks are approaching that,

but not quite there,

but we do believe that we see something there.

NARRATOR: Blake believes she has detected the faint signal of life

at 3.8 billion years ago, only 700 million years

after Earth was created, early in the blue phase.

There is still much that we don't know

about our early planet, but some things are becoming clearer.

If you could transport yourself back in time

about four billion years, parts of our Earth

might not look too different

than this Southern California beach,

minus the surfers and poodle.

You could stand on cliffs, probably of granite,

overlooking oceans that were increasingly rich

with minerals and early microbial life.

But you would quickly die in a great deal of pain,

suffocating in the heavy atmosphere

rich in nitrogen and carbon dioxide,

but lacking in life-giving free oxygen.

Then something truly astonishing happened.

Those harmless-looking microbes

floating in the water or on stromatolites

started to change everything, turning Earth red.

HAZEN: Wow.

Oh, my God, this is amazing!

There aren't many places on earth

you can see something like this.

NARRATOR: A remnant of red Earth can be seen in Australia

at the Hamersley Basin in Karijini National Park.

In these rocks, Hazen finds

a startling consequence of early life

as it began to thrive and evolve.

What we're seeing here is one of the greatest tricks

that life ever figured out.

And that was how to take sunlight

and convert it to energy.

NARRATOR: Microbes, like those in the stromatolites at Shark Bay,

eventually began to live off the sun's energy

through photosynthesis.

That led to a dramatic rise

in a gas that Earth was not accustomed to:

oxygen.

While to us, oxygen is a life-giving benign gas,

to a world not accustomed to it,

oxygen created a dangerously corrosive cocktail.

The early oceans were filled with dissolved iron.

The new oxygen reacted with that iron,

and it began to rust

and sank to the bottom of the sea.

HAZEN: These little microbes, they're microscopic things,

and you wouldn't think they could do all that much.

But when they produce that oxygen

and the oxygen reacts with the iron in the oceans,

you get the world's largest deposits of iron--

thousands of feet covering hundreds of square miles.

NARRATOR: These formations cover a vast area

with trillions of tons of iron ore.

That is an unimaginable consequence

of trillions upon trillions of microbes breathing.

HAZEN: It's a fundamental change in the chemistry of Earth.

It's a consequence of the rise of oxygen.

NARRATOR: The rise in oxygen that rusted iron

and sent Earth into the red phase

also created many new minerals.

HAZEN: As a mineralogist, when I look at Earth history,

I see big transitions.

I see the moon forming impact,

I see the formation of oceans and so forth.

But nothing, nothing matches

what life and oxygen did to create new minerals.

NARRATOR: Some estimate that the meteorites that formed Earth

began with only about 250 minerals.

Today, there are more than 5,000.

Hazen believes that two-thirds of all the minerals

that now make up our planet

were created by the introduction of oxygen.

And most of that was, in turn, created by life.

BOY: Amethyst.

HAZEN: It's mindboggling.

Rocks create life, life creates rocks.

They're intertwined in ways that are just now coming into focus.

NARRATOR: But the road ahead for life and for rocks

would not be easy.

As we head into the next phase of Earth,

new continents formed and broke apart,

which may have created dramatic extremes in the climate.

Earth plunged into an icy freeze, turning it white.

In these frozen conditions, life was nearly wiped out.

Fortunately, active volcanoes

still poked through the icy veneer,

billowing out carbon dioxide, or CO2.

Like a thermal blanket around our Earth,

this kept heat in and rescued life.

HAZEN: Life all but shut down.

And then the CO2 rises and rises

and the greenhouse effect gets hotter and hotter,

and suddenly the planet melts.

NARRATOR: Cycles of these snowball hothouse conditions

had profound consequences for life.

One result was more oxygen,

which eventually allowed for bigger animals.

The dramatic changes during white Earth

would bring us to the present phase

starting about 540 million years ago--

a living planet

filled with diverse plants and spectacular creatures.

But those life-forms are pitted against each other

in a survival of the fittest,

and rocks can make the difference

between life and death.

That struggle can be seen back in Morocco,

at the edge of the Anti-Atlas Mountains.

Here, Bob Hazen and Adam Aronson

are looking for evidence of an evolutionary trick

that shows once again how life and rocks

took a big leap forward together.

520 million years ago,

this valley was a shallow ocean filled with new forms of life.

This is when the diversity of life on Earth exploded,

all thriving in a living sea.

HAZEN: So if you were a scuba diver and you dove down to this reef,

you'd see all kinds of life swimming around,

really amazing, probably very colorful, too.

NARRATOR: There is one creature that dominates this ancient reef

that Hazen wants to find.

HAZEN: Nothing there.

Nothing there.

And nothing there.

NARRATOR: Fossil hunting is a game of luck and persistence,

but it doesn't take long for Hazen to strike geologic gold.

Whoa!

Jeez, look at that.

That is amazing.

NARRATOR: The trilobite.

HAZEN: Hey, look, there's another head there,

and the head there, two more.

Boy, this is rich rock.

The trilobites here are amazing

because these are the oldest animals that you can find

that are preserved as what you think of as a fossil

that you can hold in your hand.

NARRATOR: Some trilobites were like horseshoe crabs

scurrying about the ocean floor.

The reason they are found as fossils today

is because they developed

an astonishing evolutionary trick...

shells.

Trilobite shells were made of calcium carbonate,

the same mineral found in limestone,

the rock that built the pyramids.

In effect, life itself began to make rocks

for its own advantage.

And the idea went viral.

HAZEN: If you had a shell, you're going to survive a lot longer

than that soft-bodied animal that doesn't have a shell.

The trilobite had an advantage.

It's survival of the fittest.

NARRATOR: The trilobite's mineral shell

heralded a new phase in the evolution of animals,

catapulting our planet into the present stage,

green earth, one that is rich in diverse life.

From humans back to trilobites, we owe our evolution

and survival to the world of minerals--

with shells, then eventually with bones and teeth

that paved the way for life to grow taller and stronger.

All are evidence of life co-opting minerals

for its own evolutionary advantage.

HAZEN: We've thought for centuries,

"Animals, minerals, they're separate kingdoms, right?"

But it turns out they overlap,

they're intertwined, they co-evolved.

That life makes minerals,

and minerals have led to new life-forms.

You can't separate the two.

Life and rocks are totally intertwined

through billions of years of Earth history.

NARRATOR: One of Hazen's favorite places

to see this intertwined history of life and minerals

is at the Calvert Cliffs along the Chesapeake Bay.

He and his wife Margee

pick up shells and shark teeth from a time

18 million years ago when massive sea creatures swam here.

That's nice, isn't that pretty?

HAZEN: You find teeth

along the beach that are five, six, sometimes seven inches long

with serrated edges-- razor-sharp teeth.

These were immense creatures,

sharks that may have been 50 or 60 feet long.

NARRATOR: These giants of the sea

would have dwarfed today's great whites.

And it was the bones and teeth created with minerals

that enabled them to grow so large and powerful.

HAZEN: They were feeding on whales.

Dolphins would have been a snack.

NARRATOR: They are just one small part of a story of co-evolution

stretching back to Earth's beginning.

HAZEN: The life, the rocks, it's all part of the same story.

NARRATOR: Step by step, throughout Earth's evolution,

minerals and life have sparked chemical reactions

that sculpted the planet into what we see today

and helped create the life we know.

HAZEN: At this place, you get a sense of the immensity of time

and the constancy of change.

Life is creating and sculpting our surroundings

in ways that are quite wonderful.

And just to recognize the power of life to transform a planet.

(engine revving)

Of course, humans transform the planet too.

We build cities, we build roads,

we change the composition of the atmosphere

and change the composition of the oceans.

There are going to be global changes.

NARRATOR: These changes whose consequences are now beginning to unfold

are the latest chapter in Earth's epic story--

a story that began

four and a half billion years ago with a rock.

The exploration continues online,

This NOVA program is available on DVD.

To order, visit shopPBS.org, or call 1-800-PLAY-PBS.

NOVA is also available for download on iTunes.