Nova (1974–…): Season 43, Episode 2 - Life's Rocky Start - full transcript
Four and a half billion years ago, the young Earth was a hellish place-a seething chaos of meteorite impacts, volcanoes belching noxious gases, and lightning flashing through a thin, torrid atmosphere. Then, in a process that has ...
They're dazzling
Priceless
At times, even glowing
How can one not fall in love
with rocks and minerals?
I mean, the colors, the shapes
And they're the building blocks
of modern civilization
We wouldn't have televisions,
we wouldn't have automobiles,
we wouldn't have buildings
without the mineral riches
that we have
But could rocks and minerals
also solve the greatest mystery
of all time...
The origin of life?
The rocks we pick up
tell a story:
that life couldn't have occurred
without rocks
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
From its first spark
People were saying they made
Frankenstein in a test tube
to the survival of the fittest
These were immense creatures...
Sharks that may have been
50 or 60 feet
Was it the secret link
between rocks and life
that made the difference?
"Life's Rocky Start,"
right now on NOVA.
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
Look at that vein of calcite
Rocks
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
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
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
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
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
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
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
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
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
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
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
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
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
Every rock, you slice it open,
you look inside,
there's something special
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
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 stronger,
or add a pinch of cobalt
and your iPhone battery
will last longer
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
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
So when did Earth cool enough
to have liquid water,
this element key to life?
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
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
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
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
To tell that story,
John Valley must first find
the tiny crystals...
The ultimate
needle in a haystack
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
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
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
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
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?
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
And if water is a key
starting point for life,
could there be life
that early, too?
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
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
that a 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
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
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
It looks like this sort of a
Frankenstein-type apparatus
But actually, it's a very
carefully thought out design
Bada sets up a modern-day test
of the 1950s experiment
on Miller's original
lab equipment
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
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
Miller and Urey decided to use
a spark to simulate lightning
because that's such
a ubiquitous process
in the atmosphere of the earth
That was the real inspiration,
these little electric sparks
they acted like simulated
lightning
The energy from the spark
of lightning
breaks down
the gas and water molecules
so they can undergo
further chemical reactions
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
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
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
The experiment raised the fear
that a Frankenstein creation,
like in this classic film,
was just around the corner
It's moving
People were saying they made
Frankenstein in a test tube
It's alive!
Now I know what it feels
like to be God!
Had Miller and Urey cooked up
life in a test tube?
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
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
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
My first thought was gee,
why don't we do
a Miller-Urey experiment,
but do it at high temperature,
high pressures?
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
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
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
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
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
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?
They run the experiment again
And this time the atoms reform
into new organic molecules...
Including amino acids
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"
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
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
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
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
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
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
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
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
I can't believe these rocks
are three and a half billion
years old
They look like they formed
last week
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!
And then if you look
a bit further back,
you see a very large
domical structure
There's no obvious way
that a chemical or physical
process would form that
Exactly
These strange shapes
are fossilized remnants of life
called stromatolites,
beautifully preserved
in these ancient rocks
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
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
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
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
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
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
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
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
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
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
The crime has been committed
The criminal is gone,
but they've left behind
some indicator
because they've changed
their environment
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
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
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
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
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
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
Wow
Oh, my God, this is amazing!
There aren't many places
on earth
you can see something like this
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
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
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
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
It's a fundamental change
in the chemistry of Earth
It's a consequence
of the rise of oxygen
The rise in oxygen
that rusted iron
and sent Earth
into the red phase
also created many new minerals
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
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
Amethyst
It's mindboggling
Rocks create life,
life creates rocks
They're intertwined in ways that
are just now coming into focus
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
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
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
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
There is one creature that
dominates this ancient reef
that Hazen wants to find
Nothing there
Nothing there
And nothing there
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
The trilobite
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
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
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
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
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
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?
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
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
They were feeding on whales
Dolphins would have been a snack
They are just one small part
of a story of co-evolution
stretching back
to Earth's beginning
The life, the rocks,
it's all part of the same story
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
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
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
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
Priceless
At times, even glowing
How can one not fall in love
with rocks and minerals?
I mean, the colors, the shapes
And they're the building blocks
of modern civilization
We wouldn't have televisions,
we wouldn't have automobiles,
we wouldn't have buildings
without the mineral riches
that we have
But could rocks and minerals
also solve the greatest mystery
of all time...
The origin of life?
The rocks we pick up
tell a story:
that life couldn't have occurred
without rocks
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
From its first spark
People were saying they made
Frankenstein in a test tube
to the survival of the fittest
These were immense creatures...
Sharks that may have been
50 or 60 feet
Was it the secret link
between rocks and life
that made the difference?
"Life's Rocky Start,"
right now on NOVA.
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
Look at that vein of calcite
Rocks
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
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
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
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
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
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
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
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
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
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
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
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
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
Every rock, you slice it open,
you look inside,
there's something special
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
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 stronger,
or add a pinch of cobalt
and your iPhone battery
will last longer
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
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
So when did Earth cool enough
to have liquid water,
this element key to life?
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
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
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
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
To tell that story,
John Valley must first find
the tiny crystals...
The ultimate
needle in a haystack
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
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
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
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
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?
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
And if water is a key
starting point for life,
could there be life
that early, too?
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
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
that a 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
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
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
It looks like this sort of a
Frankenstein-type apparatus
But actually, it's a very
carefully thought out design
Bada sets up a modern-day test
of the 1950s experiment
on Miller's original
lab equipment
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
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
Miller and Urey decided to use
a spark to simulate lightning
because that's such
a ubiquitous process
in the atmosphere of the earth
That was the real inspiration,
these little electric sparks
they acted like simulated
lightning
The energy from the spark
of lightning
breaks down
the gas and water molecules
so they can undergo
further chemical reactions
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
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
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
The experiment raised the fear
that a Frankenstein creation,
like in this classic film,
was just around the corner
It's moving
People were saying they made
Frankenstein in a test tube
It's alive!
Now I know what it feels
like to be God!
Had Miller and Urey cooked up
life in a test tube?
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
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
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
My first thought was gee,
why don't we do
a Miller-Urey experiment,
but do it at high temperature,
high pressures?
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
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
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
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
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
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?
They run the experiment again
And this time the atoms reform
into new organic molecules...
Including amino acids
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"
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
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
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
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
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
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
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
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
I can't believe these rocks
are three and a half billion
years old
They look like they formed
last week
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!
And then if you look
a bit further back,
you see a very large
domical structure
There's no obvious way
that a chemical or physical
process would form that
Exactly
These strange shapes
are fossilized remnants of life
called stromatolites,
beautifully preserved
in these ancient rocks
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
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
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
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
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
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
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
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
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
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
The crime has been committed
The criminal is gone,
but they've left behind
some indicator
because they've changed
their environment
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
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
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
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
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
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
Wow
Oh, my God, this is amazing!
There aren't many places
on earth
you can see something like this
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
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
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
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
It's a fundamental change
in the chemistry of Earth
It's a consequence
of the rise of oxygen
The rise in oxygen
that rusted iron
and sent Earth
into the red phase
also created many new minerals
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
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
Amethyst
It's mindboggling
Rocks create life,
life creates rocks
They're intertwined in ways that
are just now coming into focus
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
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
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
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
There is one creature that
dominates this ancient reef
that Hazen wants to find
Nothing there
Nothing there
And nothing there
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
The trilobite
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
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
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
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
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
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?
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
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
They were feeding on whales
Dolphins would have been a snack
They are just one small part
of a story of co-evolution
stretching back
to Earth's beginning
The life, the rocks,
it's all part of the same story
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
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
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
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