WEBVTT

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More than four billion years
ago, the most important event

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in the history of the
earth took place.

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The ocean was born.

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It completely transformed the
planet, creating a watery

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oasis that gave rise to the air
we breathe, our climate,

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and a stunning array of life,
including the critical species

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that first crawled out of the
ocean to inhabit land.

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We\'re looking at an animal
that\'s really at the base of

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the branch in the tree
of life that leads

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to all limbed animals.

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And we\'re a limbed animal.

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The story of the ocean is the
story of mass extinctions and

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of astonishing survival in one
of the most beautiful and

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mysterious parts
of the planet.

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Ultimately, the history of the
ocean is our own history.

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And today, we are just beginning
to understand its

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complexity, and the immense
influence it has on the

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planet, and on our
own survival.

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Our vast ocean stretches out
over space and time.

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It\'s almost as old as
the planet itself.

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Yet for most of us, the ocean
is a shoreline, a watery

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surface, a mystery.

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There\'s an amazing world beneath
these waves, but it\'s

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fragile and threatened.

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In this four part series, we\'ll
join the scientists who

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are unlocking the secrets, and
exploring the wonders of this

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most critical life force on
the planet, the ocean.

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We live on a blue planet which
is almost all ocean.

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A water planet that is unique
among the cosmos.

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But where did all this
water come from?

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And how did it transform
our planet?

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Nick Eyles, a professor of
geology at the University of

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Toronto, has a good idea of what
this planet looked like

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four and a half billion
years ago.

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He\'s traveling into the Afar
Depression, through Ethiopia\'s

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Rift Valley in the searing hot,
hot heat to descend into

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the Erta Ale, one of the
planet\'s most active

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volcanoes, to see what early
Earth must have looked like as

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it was being forged.

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It formed out of dust particles
collecting together,

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brought together by gravity.

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Meteorites bringing
in more material.

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And it was a cluster.

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Think of it as a giant, red-hot
snowball, gathering

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material from space.

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It was a red planet.

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It wasn\'t a blue planet.

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There were no oceans, there
were no atmospheres.

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A giant ball of red-hot magma
flashing through space.

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Will you just look at that?

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That\'s incredible.

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This is what the
earth once was.

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That\'s amazing.

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A planet of lava, where gases
belch up from deep within, and

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molten rock sloshes back
and forth like water.

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So if the earth started like
this, how could an ocean ever

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have formed?

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And where did all the
water come from?

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Well, there\'s been a lot of
scientific debate about the

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origin of the oceans.

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And surprisingly, the answer
appears to be that the ocean

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water came from within
the planet.

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It was water that was squeezed
out under huge, unimaginable

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pressures from rocks
and minerals.

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Imagine the forces that
are taking place

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deep within the planet.

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And the water outgassed from
the deep interior of the

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planet, and pooled on
the hot surface.

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The water vapor entered
the atmosphere

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as superheated steam.

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As it cooled, it condensed,
and rained down upon the

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planet, cooling the surface,
ponding in the depressions,

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and slowly creating the
first bodies of water.

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And eventually, an ocean.

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The ocean reshaped the Earth\'s
surface, and ultimately

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transformed it into a livable,
temperate planet that could

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support life.

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Half of the oxygen we breathe
comes from plants

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living in the ocean.

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And they absorb half of the
carbon dioxide we produce.

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The ocean acts as the
planet\'s thermostat.

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It regulates the temperature,
and prevents the Earth\'s

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surface from getting too
hot or too cold.

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The ocean not only shaped the
earth\'s surface and created

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our temperate climate.

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It nurtured life itself on this
planet, when one single

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cell first formed some 3.5
billion years ago.

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Peter Ward, a paleontologist
with the University of

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Washington, has traveled here
to Shark Bay in Western

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Australia to see what that early
life in the ocean might

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have looked like.

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Yeah, I really think this is a
view of what the world looked

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like, all the world\'s oceans,
from three and a half billion

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years ago to a half
billion years ago.

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They may look like rocks, but
these stromatolites are very

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much alive.

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They are made up of layer
upon layer of

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tiny, sticky bacteria.

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Sand and dirt particles adhere
to the bacteria, building it

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up, and giving it this
rock-like appearance.

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Stromatolites like these, here
in Shark Bay, once covered the

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ancient ocean floor.

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Every time we find fossils
of marine rocks, there\'s

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stromatolites in them.

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But they\'re gone now.

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And the disappearance of them
really can be thought of as

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perhaps one of the first and
most disastrous of all mass

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extinctions for life.

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So what happened to the
ubiquitous stromatolites?

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What forces wiped them out?

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For billions of years, this
planet was oxygen-free.

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The ocean was filled with
anaerobic bacteria that

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thrived without oxygen,
obtaining all their energy

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from rocks and minerals.

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We can think of early life
itself in ways somewhat

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analogous to energy
in our society.

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Right now we are fueled mostly
by coal and oil.

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But we\'re switching to
solar, aren\'t we?

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Well, early life
was like that.

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Early life took its energy right
out of rocks as we take

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it right out of oil wells.

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But very quickly, all that solar
power, that untouched

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resource, became available,
simply through the evolution

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of one specialized
type of cell.

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A pigment that could take
sunlight, combine it with

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carbon dioxide in the
atmosphere, and build cell

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living material.

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Stromatolites used these
pigmented cells to harness the

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sun\'s energy.

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This reaction, called
photosynthesis, released one

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revolutionary byproduct.

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Oxygen.

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The presence of oxygen was, in
reality, just a mistake.

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It is a byproduct.

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Simply a metabolic byproduct.

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It\'s not as if any plant
really cares much

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about oxygen at all.

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It just tossed it away during
photosynthesis.

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The oxygen emitted by
stromatolites accumulated in

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the ocean and the atmosphere
over hundreds

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of millions of years.

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Oxygen allowed more and more
complex life to evolve into

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the ocean\'s earliest
creatures.

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The stromatolites around me
were really the agents of

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their own destruction,
in a way.

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Animals themselves duly evolved
about 550 million

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years ago, could not
photosynthesize, obviously.

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They\'re not plants.

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But they needed energy.

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They need food.

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Well, food is all around us.

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The most reliable food at that
time were stromatolites.

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And so, the early animals
which were capable

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of motion, had jaws.

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They had little rasping tongues
if they were mollusks.

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And they just grazed.

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They grazed these stromatolites

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right out of existence.

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Although today there is only a
small sample remaining, it

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would be difficult to find a
species of life that had a

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greater impact on this planet
than these humble looking

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stromatolites.

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We animals, of course, would
not be here without these

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stromatolites, or at least
their great deep time

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forebearers.

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They gave us the oxygen
atmosphere.

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Stromatolites made earth
an earth-like planet.

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Charles Darwin recognized that
all life on earth today came

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from one first cell somewhere.

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Each of us is at the top
of a great rich tree.

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[? Our ?] family tree of ours
has these stromatolites way

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down, down near it\'s
very base.

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We should revere these things.

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They did their job, if
you want to say that.

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But certainly without them,
we would not be here.

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Life on this planet started
in the ocean.

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And to this day, scientists
are still discovering new

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species of life at every turn
in some of the most extreme

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environments imaginable.

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Doctor Verena Tunnicliffe, an
ocean biologist with the

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University of Victoria, has
traveled to a part of this

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planet that few of us will ever
get to see, a place where

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the energy of the sun doesn\'t
reach, and where oxygen-hating

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bacteria still rule.

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The first time our expedition
discovered hydrothermal vents

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was actually the first time
on the Juan de Fuca

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ridge out off Canada.

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And that was about
25 years ago.

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And the feeling was just like
walking into another world.

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I was in a man submersible, so
you\'re down under the ocean

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nearly 2000 meters.

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And it\'s totally alien, quiet
world that\'s crystal clear.

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And then you go from black lavas
into this vents with

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black smokers, and animals
all over the place.

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It\'s just like going
into an oasis.

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It may look lush and alive,
but if there is a harsher

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place to live than a
hydrothermal vent, it hasn\'t

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been found yet.

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Poisonous gas, searing hot
water, heavy metals, extreme

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acidity, enormous underwater
pressure.

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This seafloor ecosystem seems
more like something from deep

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space than our own deep sea.

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Yet amazing communities of life
have taken hold around

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these vents.

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Black smokers are powered by
volcanoes, but that isn\'t

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smoke billowing out.

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It\'s hot, mineral-laced water.

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Water seeps down into the
Earth\'s hot mantle through

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cracks on the ocean floor, where
it gets superheated and

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starts to dissolve minerals
and toxic, heavy metals.

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The water, now heated to 400
degrees Celsius, boils back up

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through the sea floor.

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When the toxic mixture hits
the frigid seawater, the

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dissolved minerals and heavy
metals precipitate out,

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creating the billowing black
flumes, and building up these

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chimney-like structures.

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That life can exist under these
conditions is amazing,

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but even more so when we
consider that these creatures,

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the tubeworm, clams, and crabs,
are all sustained by

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one tiny bacterium that feeds
off this toxic chemical stew.

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So the hydrothermal vent
ecosystem is an ecosystem that

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works on something called
chemosynthesis.

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Not photosynthesis like the
rest of the planet does.

00:15:10.220 --> 00:15:13.140


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The chemical energy that powers
this remote ecosystem

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is harnessed by anaerobic
bacteria, similar to the first

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life in the ocean, who literally
eat the dissolved

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rocks and minerals belching
out of these vents.

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So the fundamental grass in
this system are microbes.

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That\'s the basis of the
whole ecosystem.

00:15:35.660 --> 00:15:42.110


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These hardy microbes that
survive on the fuel provided

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by the black smokers in turn
attract a range of

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extraordinarily adapted
creatures to

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this deep, dark site.

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So the basic food source in
this system is bacteria.

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And all of these animals have
to figure out some way of

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getting that bacteria.

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There are some animals that
have gotten to the point

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where, well, I don\'t want
to spend all my

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energy grazing bacteria.

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There\'s some crabs that grow the
bacteria on their claws.

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And they put their front claws
out into the water flow, and

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they sit there growing the
bacteria like grass.

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And then they bring them in and
they just lick their hands

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and then they put them
back out again.

00:16:34.990 --> 00:16:38.690


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An even more ingenious strategy
of getting at those

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life-sustaining microbes is
employed by the red tubeworm.

00:16:46.210 --> 00:16:50.750


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They\'re very special to many
biologists because they

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represent almost a pinnacle of
the evolutionary process.

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Apparently lowly worm has done
something that is quite

00:17:02.690 --> 00:17:04.460
extraordinary.

00:17:04.460 --> 00:17:07.060
It has no mouth, has no gut.

00:17:07.060 --> 00:17:11.109
Instead, its taken microbes,
bacteria from the environment,

00:17:11.109 --> 00:17:14.910
and inserted them in its body,
and the bacteria do all the

00:17:14.910 --> 00:17:19.099
work in terms of making
food for them.

00:17:19.099 --> 00:17:22.660
Bacteria enter young, developing
worms through an

00:17:22.660 --> 00:17:24.579
opening at the end
of their tube.

00:17:24.579 --> 00:17:29.700
But as the worm matures, the
openings in the tube close,

00:17:29.700 --> 00:17:32.552
trapping the bacteria inside.

00:17:32.552 --> 00:17:37.720
And so this has become almost a
poster child of adaptation,

00:17:37.720 --> 00:17:39.920
of how evolution has
gone through to a

00:17:39.920 --> 00:17:41.750
very extreme limit.

00:17:41.750 --> 00:17:44.190
And when we look at these
tubeworms, we can understand

00:17:44.190 --> 00:17:47.360
many of these kinds of
intriguing adaptations to very

00:17:47.360 --> 00:17:48.610
unusual conditions.

00:17:48.610 --> 00:17:54.950


00:17:54.950 --> 00:17:59.160
A harsh environment like this
promotes adaptation.

00:17:59.160 --> 00:18:02.100
There is no easy way
to make a living.

00:18:02.100 --> 00:18:04.730
For creatures to survive
down here,

00:18:04.730 --> 00:18:05.980
they have to be creative.

00:18:05.980 --> 00:18:09.460


00:18:09.460 --> 00:18:11.800
When we look at an ecosystem
like the hydrothermal vents,

00:18:11.800 --> 00:18:17.035
we realize that life often
can make the most

00:18:17.035 --> 00:18:19.970
of almost any setting.

00:18:19.970 --> 00:18:22.900
And so, given just the slightest
chance, life is

00:18:22.900 --> 00:18:26.820
probably going to take it.

00:18:26.820 --> 00:18:31.420
When it has to, life can adapt
to extreme environments.

00:18:31.420 --> 00:18:34.270
But given a more forgiving
and bountiful

00:18:34.270 --> 00:18:36.210
ecosystem, life explodes.

00:18:36.210 --> 00:18:44.240


00:18:44.240 --> 00:18:49.260
Around 600 million years ago,
multicellular animals started

00:18:49.260 --> 00:18:51.230
to take over the ocean.

00:18:51.230 --> 00:18:57.740
The first coral and sponge reefs
provided the ideal home.

00:18:57.740 --> 00:19:02.060
The tight spaces and maze-like
design feed and protect a

00:19:02.060 --> 00:19:06.150
multitude of species, and offer
a steady diet for the

00:19:06.150 --> 00:19:07.400
many predators.

00:19:07.400 --> 00:19:12.470


00:19:12.470 --> 00:19:15.780
This is what a coral reef
looks like from above.

00:19:15.780 --> 00:19:19.340
It\'s an inviting image of
crystal clear blue water,

00:19:19.340 --> 00:19:22.730
teeming with life of every
shape, size, and color.

00:19:22.730 --> 00:19:29.460


00:19:29.460 --> 00:19:32.790
And this is what a coral reef
looks like after it\'s been

00:19:32.790 --> 00:19:36.555
left out in the sun for over
400 million years.

00:19:36.555 --> 00:19:39.550


00:19:39.550 --> 00:19:44.000
Professor Peter Ward has come to
Western Australia to study

00:19:44.000 --> 00:19:47.830
this ancient reef and try to
unlock the secrets it holds.

00:19:47.830 --> 00:19:50.410


00:19:50.410 --> 00:19:52.350
I\'ve seen plenty of
Devonian reefs.

00:19:52.350 --> 00:19:55.830
But every single Devonian reef
I\'ve ever seen has been

00:19:55.830 --> 00:20:00.510
subjected to millions of years
of insult by the planet,

00:20:00.510 --> 00:20:04.242
tilted up, or squished, or
turned into some other rock.

00:20:04.242 --> 00:20:07.610
The extraordinary aspect of this
place, this reef lived

00:20:07.610 --> 00:20:10.300
and died, and then was
left completely

00:20:10.300 --> 00:20:11.550
alone by Mother Earth.

00:20:11.550 --> 00:20:16.580


00:20:16.580 --> 00:20:21.460
These razor sharp formations are
gravestones for what was

00:20:21.460 --> 00:20:24.800
once a global network
of reefs.

00:20:24.800 --> 00:20:29.170
During the Devonian period, over
400 million years ago,

00:20:29.170 --> 00:20:32.550
barrier reefs built up in the
shallow waters around the

00:20:32.550 --> 00:20:33.800
continents.

00:20:33.800 --> 00:20:44.000


00:20:44.000 --> 00:20:46.970
We could go to the Great Barrier
Reef in Australia,

00:20:46.970 --> 00:20:49.940
look at that clear water,
examine those reefs, and we

00:20:49.940 --> 00:20:51.730
would have a very good
picture of what it

00:20:51.730 --> 00:20:53.720
would have looked like.

00:20:53.720 --> 00:20:55.830
Biodiversity is enormous.

00:20:55.830 --> 00:20:58.260
The water would be
crystal clear.

00:20:58.260 --> 00:20:59.280
We would see a wall.

00:20:59.280 --> 00:21:01.770
The wall would be covered
with corals.

00:21:01.770 --> 00:21:03.980
But way more than that, there\'d
be archaic creatures

00:21:03.980 --> 00:21:05.542
now extinct.

00:21:05.542 --> 00:21:09.290
We\'re looking at a time before
we had all the fish of today.

00:21:09.290 --> 00:21:12.640
These are archaic, they have
big scales, they\'re clunky.

00:21:12.640 --> 00:21:15.340
They kind of look like
swimming tanks.

00:21:15.340 --> 00:21:19.330
But it would be so colorful,
so diverse, so filled with

00:21:19.330 --> 00:21:22.175
life, that we could compare it
to the modern day reefs.

00:21:22.175 --> 00:21:26.330


00:21:26.330 --> 00:21:28.080
I\'m holding a piece of
reef that came from

00:21:28.080 --> 00:21:29.740
this rock behind me.

00:21:29.740 --> 00:21:32.500
Every bit of white that you see
in this hunk of rock was

00:21:32.500 --> 00:21:33.740
formed by an animal.

00:21:33.740 --> 00:21:35.180
Not just an animal.

00:21:35.180 --> 00:21:37.690
Thousands of species
of animals.

00:21:37.690 --> 00:21:40.650
Coral-like animals entered
corals themselves, building

00:21:40.650 --> 00:21:43.780
skeletons, growing up into
sunlight, making

00:21:43.780 --> 00:21:45.620
a giant coral city.

00:21:45.620 --> 00:21:47.270
Now look right behind that.

00:21:47.270 --> 00:21:48.610
The rocks turn black.

00:21:48.610 --> 00:21:51.630
The rocks above us, the younger
rocks, have been taken

00:21:51.630 --> 00:21:53.430
over by something entirely
different.

00:21:53.430 --> 00:21:56.700


00:21:56.700 --> 00:21:58.900
It\'s no longer an animal reef.

00:21:58.900 --> 00:22:01.130
It\'s now a microbial reef.

00:22:01.130 --> 00:22:02.390
The animals are wiped out.

00:22:02.390 --> 00:22:05.560
What takes over was what
was present on

00:22:05.560 --> 00:22:07.070
earth before animals.

00:22:07.070 --> 00:22:08.320
Microbes.

00:22:08.320 --> 00:22:11.180


00:22:11.180 --> 00:22:12.960
It was one of the greatest
mass extinctions in the

00:22:12.960 --> 00:22:14.470
history of the planet.

00:22:14.470 --> 00:22:16.060
This place is a graveyard.

00:22:16.060 --> 00:22:17.490
And we are just now
beginning to

00:22:17.490 --> 00:22:19.360
understand what caused that.

00:22:19.360 --> 00:22:22.430
And personally, it scares the
holy business out of me.

00:22:22.430 --> 00:22:24.460
Because what caused that
very much could happen

00:22:24.460 --> 00:22:27.620
again in our world.

00:22:27.620 --> 00:22:32.810
Over 99.9% of species that ever
lived on this planet are

00:22:32.810 --> 00:22:34.320
now extinct.

00:22:34.320 --> 00:22:36.090
They\'ve come, and
they\'ve gone.

00:22:36.090 --> 00:22:38.950


00:22:38.950 --> 00:22:43.360
Over the past 540 million years,
there have been five

00:22:43.360 --> 00:22:47.770
major extinctions when over
50% of the planet\'s animal

00:22:47.770 --> 00:22:50.830
species were wiped out.

00:22:50.830 --> 00:22:53.620
When I began my career, we
thought that every one of the

00:22:53.620 --> 00:22:56.565
mass extinctions had been caused
by a large body impact,

00:22:56.565 --> 00:22:59.035
a comet or an asteroid
hitting the planet.

00:22:59.035 --> 00:23:01.360
It made great sense.

00:23:01.360 --> 00:23:05.320
But Professor Ward and many
other paleontologists now

00:23:05.320 --> 00:23:08.660
believe that the extinctions
weren\'t caused by a huge

00:23:08.660 --> 00:23:13.320
asteroid, but by a
tiny bacterium.

00:23:13.320 --> 00:23:16.660
The edge of this really stagnant
river in Australia is

00:23:16.660 --> 00:23:19.330
a great place to illustrate what
happened at the end of

00:23:19.330 --> 00:23:21.090
the Devonian.

00:23:21.090 --> 00:23:24.120
All over the edge of this,
we find bacteria.

00:23:24.120 --> 00:23:26.550
This is blue green algae,
we call it.

00:23:26.550 --> 00:23:27.450
But it is a bacterium.

00:23:27.450 --> 00:23:30.330
It\'s here because there\'s almost
no oxygen in this water

00:23:30.330 --> 00:23:31.950
because it\'s so hot.

00:23:31.950 --> 00:23:34.950
These things cover over whatever
animals were present

00:23:34.950 --> 00:23:36.125
and suffocate them.

00:23:36.125 --> 00:23:38.190
Well, the same thing happened
at the end of the Devonian

00:23:38.190 --> 00:23:39.760
with these coral reefs.

00:23:39.760 --> 00:23:42.340
The water got so warm,
it lost its oxygen.

00:23:42.340 --> 00:23:44.620
The microbes grew over
the top of the corals

00:23:44.620 --> 00:23:46.300
and smothered them.

00:23:46.300 --> 00:23:48.360
Microbes, which love hot.

00:23:48.360 --> 00:23:52.270
Microbes, which love dirty,
oxygen-free water.

00:23:52.270 --> 00:23:57.150
Microbes, which use slime to
build, and to build upon what

00:23:57.150 --> 00:23:59.470
the animals left behind.

00:23:59.470 --> 00:24:02.530
These bacteria are anaerobic.

00:24:02.530 --> 00:24:04.990
Oxygen is like kryptonite
to them.

00:24:04.990 --> 00:24:08.640
It kills them on contact.

00:24:08.640 --> 00:24:11.890
So if the ancient coral reefs
were covered with

00:24:11.890 --> 00:24:16.010
oxygen-hating microbes, the
ocean must have lost all of

00:24:16.010 --> 00:24:17.460
its oxygen.

00:24:17.460 --> 00:24:19.000
But how could that
have happened?

00:24:19.000 --> 00:24:24.600


00:24:24.600 --> 00:24:28.640
Oxygen gets mixed into the ocean
by the churning action

00:24:28.640 --> 00:24:32.520
of waves, currents, and
tides on the surface.

00:24:32.520 --> 00:24:36.510
But it\'s the great ocean
conveyor that takes oxygen to

00:24:36.510 --> 00:24:39.330
the ocean\'s deepest depths.

00:24:39.330 --> 00:24:43.500
The conveyor moves surface water
warmed at the equator

00:24:43.500 --> 00:24:45.180
toward the poles.

00:24:45.180 --> 00:24:49.510
As the water cools, it becomes
denser and sinks to the deep

00:24:49.510 --> 00:24:52.960
ocean, taking life sustaining
oxygen with it.

00:24:52.960 --> 00:24:56.100


00:24:56.100 --> 00:24:58.240
How do we turn off
the conveyor?

00:24:58.240 --> 00:25:00.830
We simply remove the difference
in temperature

00:25:00.830 --> 00:25:03.210
between the poles
and the tropics.

00:25:03.210 --> 00:25:04.490
We warm the poles.

00:25:04.490 --> 00:25:06.860
We keep the tropics the
same temperature.

00:25:06.860 --> 00:25:11.940
That conveyor, which is driven
by heat differences, stops.

00:25:11.940 --> 00:25:15.450
When it stops, we lose oxygen
on the bottom, and we start

00:25:15.450 --> 00:25:17.060
the mechanism to mass
extinction.

00:25:17.060 --> 00:25:23.920


00:25:23.920 --> 00:25:27.310
Once the conveyor shuts down
and the ocean becomes

00:25:27.310 --> 00:25:31.346
stagnant, a deadly chain
reaction is put in motion.

00:25:31.346 --> 00:25:34.420


00:25:34.420 --> 00:25:37.660
The reefs were in water that
became warmer and warmer.

00:25:37.660 --> 00:25:39.680
Warm water holds less oxygen.

00:25:39.680 --> 00:25:41.990
The animals strangled
and died.

00:25:41.990 --> 00:25:45.430
The microbes grew right
over the top.

00:25:45.430 --> 00:25:47.400
Worse things then started
to happen.

00:25:47.400 --> 00:25:50.790
In that warm water, not only did
we get green microbes like

00:25:50.790 --> 00:25:54.140
this, but a second entire
type began to grow.

00:25:54.140 --> 00:25:56.410
A microbe that produces
the very toxic

00:25:56.410 --> 00:25:59.250
poison hydrogen sulfide.

00:25:59.250 --> 00:26:01.300
Hydrogen sulfide is a killer.

00:26:01.300 --> 00:26:05.530
This lethal form of bacterium
gets its energy by breaking

00:26:05.530 --> 00:26:07.210
down sulfur.

00:26:07.210 --> 00:26:11.460
However in doing so, it creates
hydrogen sulfide, a

00:26:11.460 --> 00:26:13.232
deadly byproduct.

00:26:13.232 --> 00:26:16.200
These microbes began to take
over not just the reefs, not

00:26:16.200 --> 00:26:18.700
just the shallow waters,
but all the oceans.

00:26:18.700 --> 00:26:22.280


00:26:22.280 --> 00:26:24.930
Huge bubbles of hydrogen sulfide
come out of solution.

00:26:24.930 --> 00:26:28.500
They hit the surface, they pop
out, they rise into the sky.

00:26:28.500 --> 00:26:32.140


00:26:32.140 --> 00:26:34.660
In so doing, they poison
the animals.

00:26:34.660 --> 00:26:37.290
They poison plants on land.

00:26:37.290 --> 00:26:40.090
They fill the atmosphere with
toxic hydrogen sulfide.

00:26:40.090 --> 00:26:44.470


00:26:44.470 --> 00:26:46.760
The bodies are stacked up
on the beach or on the

00:26:46.760 --> 00:26:47.920
bottom of the ocean.

00:26:47.920 --> 00:26:49.870
But the ocean itself has
changed, changed

00:26:49.870 --> 00:26:51.420
entirely in its color.

00:26:51.420 --> 00:26:52.560
It\'s purple now.

00:26:52.560 --> 00:26:54.563
It\'s totally filled with
purple sulfur bacteria.

00:26:54.563 --> 00:26:57.870


00:26:57.870 --> 00:27:00.740
This sky takes on a vaguely
greenish cast.

00:27:00.740 --> 00:27:03.920
A purple ocean, a green sky, a
world without animals, a world

00:27:03.920 --> 00:27:05.980
replete, filled with microbes.

00:27:05.980 --> 00:27:09.530
That\'s the aftermath of a
greenhouse mass extinction.

00:27:09.530 --> 00:27:13.220
Scientists now believe that
this catastrophic chain of

00:27:13.220 --> 00:27:17.930
events caused all but one of
the five major extinctions.

00:27:17.930 --> 00:27:21.210
Well the mass extinctions, we
now believe, were times when

00:27:21.210 --> 00:27:23.730
the evil empire, if you will,
the first life on earth, the

00:27:23.730 --> 00:27:26.750
microbial life, fights back.

00:27:26.750 --> 00:27:28.950
It makes a huge comeback.

00:27:28.950 --> 00:27:30.560
We animals think with our

00:27:30.560 --> 00:27:32.000
complexity, we\'re here forever.

00:27:32.000 --> 00:27:33.640
But that\'s not the case.

00:27:33.640 --> 00:27:37.840
Environmental conditions are
so narrow for we animals.

00:27:37.840 --> 00:27:40.110
Our conditions for temperature
are narrow.

00:27:40.110 --> 00:27:42.700
For acidity, for the
salt in the water.

00:27:42.700 --> 00:27:45.170
Slight variation, and we die.

00:27:45.170 --> 00:27:47.270
Microbes can take hotter
temperatures, colder

00:27:47.270 --> 00:27:47.840
temperatures.

00:27:47.840 --> 00:27:50.980
Greater acid, less acid, greater
salt, less salt.

00:27:50.980 --> 00:27:56.710
In all ways, they\'re much more
widely adapted and adaptable.

00:27:56.710 --> 00:28:00.230
Microbes will be the last
life on this planet.

00:28:00.230 --> 00:28:02.620
But are there certain creatures
that are better

00:28:02.620 --> 00:28:05.225
suited for surviving
mass extinctions?

00:28:05.225 --> 00:28:09.000


00:28:09.000 --> 00:28:12.136
Extinction is the fate
of all species.

00:28:12.136 --> 00:28:16.530
However, there are creatures
called living fossils that are

00:28:16.530 --> 00:28:20.210
somehow able to survive the
constant onslaught of new

00:28:20.210 --> 00:28:22.550
predators and drastically
changing

00:28:22.550 --> 00:28:24.125
conditions in the ocean.

00:28:24.125 --> 00:28:26.750


00:28:26.750 --> 00:28:28.780
Just like in any good
army movie,

00:28:28.780 --> 00:28:29.870
there\'s always some survivors.

00:28:29.870 --> 00:28:31.960
You can\'t wipe out everybody.

00:28:31.960 --> 00:28:35.540
In the mass extinctions, not all
the animals got wiped out.

00:28:35.540 --> 00:28:37.267
Obviously, here we are,
surrounded by

00:28:37.267 --> 00:28:38.517
this animal-rich world.

00:28:38.517 --> 00:28:43.560


00:28:43.560 --> 00:28:46.500
Living fossils are just examples
of the fact that once

00:28:46.500 --> 00:28:49.590
in a while, evolution gets
it supremely right

00:28:49.590 --> 00:28:51.100
early in the game.

00:28:51.100 --> 00:28:52.850
You never have to
change anything.

00:28:52.850 --> 00:29:01.440


00:29:01.440 --> 00:29:04.365
But really, one of the most
interesting areas of research

00:29:04.365 --> 00:29:06.386
is to figure out why.

00:29:06.386 --> 00:29:10.290
Why did some die and
why did some live?

00:29:10.290 --> 00:29:14.300
To answer that question,
Professor Peter Ward is going

00:29:14.300 --> 00:29:17.500
in search of one of the greatest
survivors this planet

00:29:17.500 --> 00:29:19.510
has ever known, the nautilus.

00:29:19.510 --> 00:29:22.520


00:29:22.520 --> 00:29:24.350
It wasn\'t the biggest, or the

00:29:24.350 --> 00:29:27.080
deadliest, or even the fastest.

00:29:27.080 --> 00:29:30.780
And yet somehow, it outlasted
them all.

00:29:30.780 --> 00:29:35.140
Here\'s an animal, 500
million years.

00:29:35.140 --> 00:29:38.820
I put my 500 million year old
nautilus up against any other

00:29:38.820 --> 00:29:40.930
animal on this planet.

00:29:40.930 --> 00:29:43.910
How do you survive
500,000 years?

00:29:43.910 --> 00:29:46.240
I mean, humans are only
200,000 years.

00:29:46.240 --> 00:29:47.810
We\'re not a million.

00:29:47.810 --> 00:29:48.840
500 million.

00:29:48.840 --> 00:29:49.650
They\'ve got secrets.

00:29:49.650 --> 00:29:50.600
They know something.

00:29:50.600 --> 00:29:51.620
They\'re doing something right.

00:29:51.620 --> 00:29:53.480
Well, and what have they got
to teach us about surviving

00:29:53.480 --> 00:29:54.930
mass extinctions?

00:29:54.930 --> 00:29:57.270
So could be some pretty
important things to learn.

00:29:57.270 --> 00:30:03.850


00:30:03.850 --> 00:30:07.150
Professor Ward and Andy Dunstan
from the University of

00:30:07.150 --> 00:30:11.680
Queensland have come to Osprey
reef to trap nautilus and

00:30:11.680 --> 00:30:15.036
study their unique adaptations
for survival.

00:30:15.036 --> 00:30:16.494
OK, here you go Pete.

00:30:16.494 --> 00:30:16.980
Got it.

00:30:16.980 --> 00:30:18.438
One piggy-back trap.

00:30:18.438 --> 00:30:19.688
Got it.

00:30:19.688 --> 00:30:32.560


00:30:32.560 --> 00:30:37.570
The traps will be lowered into
the Coral Sea 150 meters down,

00:30:37.570 --> 00:30:39.320
the depth at which
the nocturnal

00:30:39.320 --> 00:30:40.880
nautilus like to feed.

00:30:40.880 --> 00:30:43.900


00:30:43.900 --> 00:30:47.130
During the day, the nautilus
stay undercover.

00:30:47.130 --> 00:30:49.860
But as night approaches,
they venture out

00:30:49.860 --> 00:30:51.193
onto the reef to feed.

00:30:51.193 --> 00:30:56.640


00:30:56.640 --> 00:31:00.190
The nautilus can\'t see in the
dark, but they use their

00:31:00.190 --> 00:31:03.370
tentacles to smell and track
down their prey.

00:31:03.370 --> 00:31:07.070


00:31:07.070 --> 00:31:11.790
Hard to imagine today, but 500
million years ago, these

00:31:11.790 --> 00:31:16.490
humble looking creatures ruled
as the ocean\'s top predator.

00:31:16.490 --> 00:31:20.680
The nautilus use their mobility
to silently stalk

00:31:20.680 --> 00:31:24.290
crab-like creatures called
trilobites, attacking from

00:31:24.290 --> 00:31:27.700
above and snapping through their
thin armour with their

00:31:27.700 --> 00:31:28.950
powerful jaws.

00:31:28.950 --> 00:31:31.380


00:31:31.380 --> 00:31:33.550
Evolution is very
much like a war.

00:31:33.550 --> 00:31:36.190
And we can think of the
nautiloids as the first

00:31:36.190 --> 00:31:38.355
airplanes coming in
on ground troops.

00:31:38.355 --> 00:31:43.340
And so, the ability of them to
crunch through creatures with

00:31:43.340 --> 00:31:46.110
their armour, thought they
were already impervious.

00:31:46.110 --> 00:31:48.130
No, these are like
big tank busters.

00:31:48.130 --> 00:31:50.740
These things are coming in,
swooping down, busting open

00:31:50.740 --> 00:31:53.130
these trilobites, and then
eating the crew.

00:31:53.130 --> 00:31:58.480


00:31:58.480 --> 00:32:02.420
The nautilus is no longer the
top predator on this reef.

00:32:02.420 --> 00:32:03.800
It\'s the shark.

00:32:03.800 --> 00:32:06.950
Another living fossil that
has defied the odds.

00:32:06.950 --> 00:32:11.980


00:32:11.980 --> 00:32:16.040
Sharks have been around for at
least 400 million years, and

00:32:16.040 --> 00:32:18.770
have flourished in every
part of the ocean.

00:32:18.770 --> 00:32:21.280


00:32:21.280 --> 00:32:25.180
Like the nautilus, they respire
while swimming, and

00:32:25.180 --> 00:32:26.845
can survive low oxygen.

00:32:26.845 --> 00:32:32.560


00:32:32.560 --> 00:32:36.780
But it\'s their hydrodynamic,
streamlined body design that

00:32:36.780 --> 00:32:40.000
gives them such a tactical
advantage over all of the

00:32:40.000 --> 00:32:42.640
other creatures in the ocean.

00:32:42.640 --> 00:32:46.770
All sharks have a pliable
skeleton made from cartilage,

00:32:46.770 --> 00:32:48.750
with no bones.

00:32:48.750 --> 00:32:51.550
It gives them strength
without weight.

00:32:51.550 --> 00:32:55.690
And it helps that sharks will
eat just about anything.

00:32:55.690 --> 00:32:58.820
During the mass extinctions,
sharks fed off the dead

00:32:58.820 --> 00:33:02.090
species piling up on
the ocean bottom.

00:33:02.090 --> 00:33:05.980
And when most of the fish were
gone, well, there were always

00:33:05.980 --> 00:33:07.230
other sharks.

00:33:07.230 --> 00:33:13.340


00:33:13.340 --> 00:33:16.980
This nautilus is going to be
fitted with a transmitter that

00:33:16.980 --> 00:33:19.790
will allow the scientists
to monitor its every

00:33:19.790 --> 00:33:21.040
move along the reef.

00:33:21.040 --> 00:33:35.320


00:33:35.320 --> 00:33:38.870
With this particular
transmitter, it will give us

00:33:38.870 --> 00:33:40.930
two very important bits
of information.

00:33:40.930 --> 00:33:44.690
At any time, we can find out
what depth he is at, and also

00:33:44.690 --> 00:33:46.490
his position.

00:33:46.490 --> 00:33:49.740
And it\'s the depth where the
nautilus live and reproduce

00:33:49.740 --> 00:33:52.530
that is the key to understanding
how they

00:33:52.530 --> 00:33:55.115
survived what the dinosaurs
couldn\'t.

00:33:55.115 --> 00:33:57.310
A deadly asteroid impact.

00:33:57.310 --> 00:34:09.760


00:34:09.760 --> 00:34:12.520
The environmental impact of an
asteroid or comet on the

00:34:12.520 --> 00:34:14.909
surface is that the surface
of the sea really

00:34:14.909 --> 00:34:16.820
got fried and acidified.

00:34:16.820 --> 00:34:21.000


00:34:21.000 --> 00:34:24.800
If the nautilus were living in
the shallow ocean, they too

00:34:24.800 --> 00:34:26.739
would have been wiped out.

00:34:26.739 --> 00:34:28.070
But they weren\'t.

00:34:28.070 --> 00:34:31.650
They had already been
chased away.

00:34:31.650 --> 00:34:34.489
After millions of years of
being preyed upon by the

00:34:34.489 --> 00:34:39.110
nautilus, the trilobites and
early fish had evolved.

00:34:39.110 --> 00:34:43.980
They became the bigger,
faster predators.

00:34:43.980 --> 00:34:47.790
The nautilus was now
under attack.

00:34:47.790 --> 00:34:50.630
If they could, they would
live at the surface.

00:34:50.630 --> 00:34:52.260
That\'s where they evolved.

00:34:52.260 --> 00:34:55.219
But they have been shoved
down by the predators.

00:34:55.219 --> 00:34:58.920
Shoved down by changing
conditions in the ocean.

00:34:58.920 --> 00:35:03.370
Ironically, those prehistoric
predators saved the nautilus

00:35:03.370 --> 00:35:06.613
from extinction when they
pursued it into the depths.

00:35:06.613 --> 00:35:09.390


00:35:09.390 --> 00:35:11.190
There was this big asteroid
collision.

00:35:11.190 --> 00:35:13.500
The surface oceans
are wiped out.

00:35:13.500 --> 00:35:17.560
Deep down, 600 feet deep, the
tiny little nautilus\' are just

00:35:17.560 --> 00:35:19.290
biding their time.

00:35:19.290 --> 00:35:21.260
When they finally come up,
the arthropods and the

00:35:21.260 --> 00:35:23.050
fish are all gone.

00:35:23.050 --> 00:35:25.900
So what we have is this one
survivor of that one great

00:35:25.900 --> 00:35:27.150
catastrophe.

00:35:27.150 --> 00:35:31.630


00:35:31.630 --> 00:35:35.310
Professor Ward contends that
ultimately, the nautilus

00:35:35.310 --> 00:35:39.650
survival record is based on
unique adaptations, good

00:35:39.650 --> 00:35:43.080
genes, and a measure
of good luck.

00:35:43.080 --> 00:35:47.470
Luck which may now
be running out.

00:35:47.470 --> 00:35:50.320
They\'ve gone through there for
every single one of the big

00:35:50.320 --> 00:35:52.910
five mass extinctions.

00:35:52.910 --> 00:35:55.290
They\'ve gotten through
greenhouses extinctions.

00:35:55.290 --> 00:35:57.630
They\'ve gotten through
asteroid extinctions.

00:35:57.630 --> 00:36:00.910
They\'ve done it through a
multiplicity of ways, and luck

00:36:00.910 --> 00:36:03.150
was certainly one of them.

00:36:03.150 --> 00:36:05.200
The real question now for a
lot of these animals and

00:36:05.200 --> 00:36:07.280
plants is, yeah, they\'ve gotten
through the past.

00:36:07.280 --> 00:36:09.240
But will they get through
the near future?

00:36:09.240 --> 00:36:12.770
And a lot of people say that we
are in a sixth extinction.

00:36:12.770 --> 00:36:15.530
I don\'t know if we are,
or we are not.

00:36:15.530 --> 00:36:18.580
But the chances are that
biodiversity is dropping and

00:36:18.580 --> 00:36:19.740
dropping fast right now.

00:36:19.740 --> 00:36:22.050
So you ask, can these long-term

00:36:22.050 --> 00:36:24.510
survivors survive us?

00:36:24.510 --> 00:36:28.820
Living fossils stopped evolving,
while other species

00:36:28.820 --> 00:36:32.520
made incredible adaptations that
would allow them to crawl

00:36:32.520 --> 00:36:34.970
out of the ocean
and onto land.

00:36:34.970 --> 00:36:56.790


00:36:56.790 --> 00:37:01.190
In 2004, Ted Daeschler, a
paleontologist with the

00:37:01.190 --> 00:37:05.560
Academy of Natural Sciences in
Philadelphia, had the chance

00:37:05.560 --> 00:37:11.490
to travel back in time, back
to when the first creature

00:37:11.490 --> 00:37:14.360
crawled out of the ocean
and onto land.

00:37:14.360 --> 00:37:16.060
Or onto the mud,
more precisely.

00:37:16.060 --> 00:37:25.930


00:37:25.930 --> 00:37:29.730
It was up in the high Canadian
Arctic where Ted uncovered a

00:37:29.730 --> 00:37:33.340
375 million year old fossil.

00:37:33.340 --> 00:37:37.250
It was a missing link that
reinforced Darwin\'s original

00:37:37.250 --> 00:37:43.110
theory that land-based animals
originally came from the sea.

00:37:43.110 --> 00:37:45.740
When we went up to Ellesmere
Island and we first started to

00:37:45.740 --> 00:37:48.370
see it in our quarry, and we
were first excavating and

00:37:48.370 --> 00:37:53.260
realizing we actually
had found something.

00:37:53.260 --> 00:37:58.670
One of our colleagues saw two
jaws stuck to a merge from the

00:37:58.670 --> 00:38:00.270
rock and called us over.

00:38:00.270 --> 00:38:03.310
And we all got very excited,
because when you see two jaws

00:38:03.310 --> 00:38:07.460
coming together in articulation,
as we say, then

00:38:07.460 --> 00:38:09.790
perhaps the whole skull
is going to be there.

00:38:09.790 --> 00:38:13.260
And indeed, as we started to
excavate a little further, we

00:38:13.260 --> 00:38:14.230
saw these two jaws.

00:38:14.230 --> 00:38:15.470
We saw a piece of a snout.

00:38:15.470 --> 00:38:19.130
And we knew that we\'d found a
complete skull with jaws.

00:38:19.130 --> 00:38:21.445
And if we were lucky, even
more of the body.

00:38:21.445 --> 00:38:24.770
And that was the first big
find of Tiktaalik.

00:38:24.770 --> 00:38:32.130


00:38:32.130 --> 00:38:35.750
There were many of those Eureka
moments, but it\'s one

00:38:35.750 --> 00:38:38.410
the reasons I\'m in paleontology
is for those

00:38:38.410 --> 00:38:39.720
discovery moments.

00:38:39.720 --> 00:38:42.290
It\'s really exciting.

00:38:42.290 --> 00:38:46.250
They dubbed the fossil
Tiktaalik, or fishapod, half

00:38:46.250 --> 00:38:50.870
fish and half four-footed
animal, the iconic creature

00:38:50.870 --> 00:38:53.920
that changed the earth forever
when it crawled out of the

00:38:53.920 --> 00:38:56.630
primordial ooze and onto land.

00:38:56.630 --> 00:38:58.330
So when we look at
the Tiktaalik.

00:38:58.330 --> 00:39:01.620
We see an animal that has a lot
of features of fish, but

00:39:01.620 --> 00:39:04.640
also many features of the
earliest limbed animals.

00:39:04.640 --> 00:39:08.170
And that\'s what makes Tiktaalik
very important.

00:39:08.170 --> 00:39:12.580
It shows us that transition
between finned animals and

00:39:12.580 --> 00:39:15.720
limbed animals.

00:39:15.720 --> 00:39:19.780
Ted has come to this coastal
estuary here in Delaware Bay

00:39:19.780 --> 00:39:23.630
along the Atlantic Ocean, to
get a better idea of the

00:39:23.630 --> 00:39:28.421
natural environment where
Tiktaalik first emerged.

00:39:28.421 --> 00:39:31.230
One of the questions that always
interests us is to

00:39:31.230 --> 00:39:33.740
understand the selective
pressures that would have

00:39:33.740 --> 00:39:37.200
created animals like Tiktaalik
And the environments where we

00:39:37.200 --> 00:39:40.950
find the fossils are ancient
settings, not unlike where I\'m

00:39:40.950 --> 00:39:45.510
standing right now, the flood
plains of streams, very muddy.

00:39:45.510 --> 00:39:47.830
Lots of these sort of
backwater settings.

00:39:47.830 --> 00:39:50.110
And these are places where it
would\'ve been a selective

00:39:50.110 --> 00:39:53.980
advantage to be able to move
through shallow water, around

00:39:53.980 --> 00:39:57.510
plants, around stumps,
and find your prey.

00:39:57.510 --> 00:40:00.110
And also to escape the
larger predators.

00:40:00.110 --> 00:40:06.000


00:40:06.000 --> 00:40:09.580
In Tiktaalik, we see the
emergence of several physical

00:40:09.580 --> 00:40:12.160
characteristics for
the first time.

00:40:12.160 --> 00:40:15.620
Characteristics that would
be incorporated by many

00:40:15.620 --> 00:40:17.970
subsequent species.

00:40:17.970 --> 00:40:21.170
Looking at Tiktaalik, we\'re
looking at an animal that\'s

00:40:21.170 --> 00:40:25.990
really at the base of the branch
in the tree of life

00:40:25.990 --> 00:40:29.280
that leads to all
limbed animals.

00:40:29.280 --> 00:40:30.520
And we\'re a limbed animal.

00:40:30.520 --> 00:40:34.450
In fact, there\'s many features
of Tiktaalik that we see in

00:40:34.450 --> 00:40:38.550
all of the subsequent limbed
animals, including ourselves.

00:40:38.550 --> 00:40:41.000
Turn your head from
side to side.

00:40:41.000 --> 00:40:43.810
This simple movement
all started with

00:40:43.810 --> 00:40:46.620
this ancient creature.

00:40:46.620 --> 00:40:50.030
Tiktaalik is the first
vertebrate to develop a free

00:40:50.030 --> 00:40:52.770
neck that allows the
head to move

00:40:52.770 --> 00:40:54.875
independently of the shoulders.

00:40:54.875 --> 00:40:59.380
A good adaptation for catching
prey in confined environments

00:40:59.380 --> 00:41:00.920
like a swamp.

00:41:00.920 --> 00:41:02.600
And there were other anatomical

00:41:02.600 --> 00:41:04.950
innovations that stuck.

00:41:04.950 --> 00:41:08.840
Tiktaalik developed mobility
in its wrist joint.

00:41:08.840 --> 00:41:12.430
It could flex the wrist to
propel itself forward, a

00:41:12.430 --> 00:41:15.780
physical trait that was passed
down through all limbed

00:41:15.780 --> 00:41:20.380
animals, all the way to us.

00:41:20.380 --> 00:41:23.190
It\'s important to realize that
Tiktaalik was an animal that

00:41:23.190 --> 00:41:26.580
was developing features that
were useful for survival in

00:41:26.580 --> 00:41:31.170
that environment, to catch prey
and to escape predation.

00:41:31.170 --> 00:41:33.480
And then later on,
as new ecological

00:41:33.480 --> 00:41:35.090
opportunities occurred--

00:41:35.090 --> 00:41:39.130
and we\'re talking millions
and millions of years--

00:41:39.130 --> 00:41:42.720
descendants of Tiktaalik
developed additional features

00:41:42.720 --> 00:41:46.320
that allowed them to exploit
the land, and eventually be

00:41:46.320 --> 00:41:48.410
free of the water completely.

00:41:48.410 --> 00:41:51.080
So what we see in Tiktaalik is
an animal that was still

00:41:51.080 --> 00:41:54.930
primarily aquatic, but
developing the features that

00:41:54.930 --> 00:41:58.140
would become useful in the
future for animals that would

00:41:58.140 --> 00:42:00.840
exploit the land.

00:42:00.840 --> 00:42:04.590
Each of us carries over three
and a half billion years of

00:42:04.590 --> 00:42:07.120
history inside of us.

00:42:07.120 --> 00:42:12.010
In every organ, cell, and gene
in our bodies is a physical

00:42:12.010 --> 00:42:15.700
connection to the rest of
life on our planet.

00:42:15.700 --> 00:42:19.260
To make sense of our own
bodies, we need only to

00:42:19.260 --> 00:42:22.970
examine the evolutionary
history we share with

00:42:22.970 --> 00:42:27.690
everything, from microbes
to mammals.

00:42:27.690 --> 00:42:30.130
When we look at our own bodies,
we can see that we

00:42:30.130 --> 00:42:33.410
share an awful lot in common
with our closest relatives,

00:42:33.410 --> 00:42:34.180
the great apes.

00:42:34.180 --> 00:42:37.460
And further down to amphibians
and even fishes.

00:42:37.460 --> 00:42:40.660
And Tiktaalik is that connection
to fishes.

00:42:40.660 --> 00:42:44.600
But we can go even deeper in the
evolutionary tree, and we

00:42:44.600 --> 00:42:46.700
can see even more
primitive forms.

00:42:46.700 --> 00:42:50.490
And the innovations and the
adaptations of those primitive

00:42:50.490 --> 00:42:52.970
forms for life in the oceans.

00:42:52.970 --> 00:42:55.810
It\'s something that we
still carry with us.

00:42:55.810 --> 00:42:58.590
And so I think we really
do have this deep, deep

00:42:58.590 --> 00:43:02.890
connection to our history, which
started in the ocean.

00:43:02.890 --> 00:43:04.520
And it\'s here in
our own bodies.

00:43:04.520 --> 00:43:06.195
We can see it.

00:43:06.195 --> 00:43:07.650
And it\'s in our psyche
as well.

00:43:07.650 --> 00:43:20.550


00:43:20.550 --> 00:43:51.472
[MUSIC PLAYING]