24x08 - Odyssey of Life: The Unknown World (2)

[bunniefuu]

Stiers: there is a world
unknown to most of us.

It exists side by
side with our own...

A world of radically
different perspectives

Where a drop of
water can be home.

Those who live here
eat the books we prize

Devour our plants

Stalk each other without mercy.

They even stalk us

Through the strange and
eerie landscapes of our bodies.

Tiny monsters

Revealed by special optics
and microphotography...

Our next-door neighbors

The stuff of nightmares,
if we dare to look.

In their world, even a
head is unfamiliar terrain.

And the palm of a hand
is like a furrowed field.

This unknown world is just
too small for us to take notice.

We see only our world,
built on our scale...

Large, open and familiar.

We don't even know
what we're missing.

In the unknown world, our
chest hair is an overgrown jungle.

Our scalp is a
tropical rain forest.

And here are the fertile
hillsides of the forearm...

The desolate desert of
the inside of the wrist...

The vast wasteland
of the sole of the foot.

The body we think we
know is really an illusion

Born of our limited perspective.

Sometimes, of course,
ignorance is bliss.

It's not easy accepting the fact

That billions of other
organisms live on and in us.

Most of them are
bacteria like these.

A microscopic swarm
in a drop of sweat.

Some of our closest companions

Have never been
introduced to us.

The hair follicle mite

Lives in holes in our scalp
through which hair grows...

A kind of tiny, parasitic mole.

It looks like a science
fiction creature

But it's only 1/250
of an inch long.

That's small enough

To escape the attention
of our nerve cells.

Otherwise, we'd
never stop scratching.

Just knowing they
exist is bad enough.

The mites especially like

The large follicles
of our eyelashes.

They thrive on fat and dirt

And have even developed
a taste for mascara.

But for other denizens
of the unknown world

There's a much more
abundant food source nearby.

It's our skin,
constantly renewed

By new cells pushing
up older ones.

The top layer is made up
of dead, compacted cells.

Every hour, we shed one
and a half million skin flakes

And each one has its own
colony of hitchhiking bacteria.

The air is full of these
small pieces of ourselves

And the microorganisms
that call them home.

What we see in the mirror

Is a layer of dead cells
soon to be cast off.

Still, even dead cells
have their appeal.

How do I look?

Absolutely beautiful.

Stiers: but change the perspective,
and it's a different story.

When we're finally
forced to face reality

We find that dead skin

Makes up 90% of the
dust on our floors

Not to mention an army of
creeping, crawling creatures.

This is the front
end of a dust mite

Seen through an
electron microscope.

It's about 1/80
of an inch long...

Impossible to see
with the naked eye.

Its diet is mostly skin flakes

And there are more than
enough to go around.

It's a never-ending feast

And we are the
purveyors, like it or not.

Dust mites are
everywhere we are.

Here we see one of
them enjoying his dinner

Although his table manners
could use a bit of improvement.

Clearly, his parents
never cautioned him

Against playing with his food.

If you think you can get away
from dust mites, think again.

Even in our beds
they keep us company.

They move easily through the
weave of blankets and sheets

In search of more food.

They scavenge when we're
awake and when we're asleep.

They are insatiable.

But why not go to the
source itself... Our own skin?

Food is everywhere,
waiting to be harvested.

But before you run to
take a shower, consider this:

Dust mites are really
sanitation workers

Who help clean up our mess.

Mites play an essential role
in the ecological process

Turning our biological
waste into their food.

So when we eat breakfast,
they eat breakfast, too.

In fact, for every
source of food

There's a group of hungry
organisms scanning the menu.

If we're not the
specialty of the house

Then something else will be.

See you tonight, darling.

I'll be home by 6:00.

Stiers: this may
look like a closet

But it's really a restaurant
for insect gourmets.

You can tell if they really
like an entree by the holes.

These small white larvae
of the common clothes moth

Are especially fond
of wool and fur.

When they're fully mature,
these well-fed larvae

Will reach the final
stage of their development

Becoming moths who will produce
the next hungry generation.

But wool and cotton aren't
the only things on the menu.

There's also a tasty fur coat,
which the fur beetle swears by.

It lives deep within
the fibers of the coat

And it lays its eggs there.

For the yellowish
brown larvae that hatch

Home is also breakfast,
lunch, and dinner.

They move using
three pairs of legs

And their jointed bodies.

Between their eyes
are powerful jaws

That can saw off
the hairs of the fur

As their legs grip
them securely.

Fur beetles are discreet
animals whom we seldom see.

We only know they're here
when we see their handiwork

Especially when their
favorite meal is a favorite dress.

But there's no point
in taking it personally.

Like us, they eat to survive.

Even in our prestigious
halls of learning

There's a legion of
ravenous creatures

Waiting for us
to turn our backs.

No door, no lock
can keep them out.

When we leave at the end
of our day, their day begins.

To these creatures

Precious books are
nothing but dead wood

No different from a
stump or fallen branch.

The subjects are irrelevant

The fine leather bindings
just more organic material...

Material to break
down and recycle.

You wouldn't know it
from looking at them

But silverfish have
an ancient pedigree.

They haven't changed
much in 500 million years.

They grow to about
a third of an inch long

And prefer old, yellowed paper.

With the help of an enzyme

They break down the
cellulose in paper into food.

Unfortunately,
they're quite illiterate

And make no distinction
between hamlet

And yesterday's newspaper.

They like them both equally.

The printed page has a number
of aficionados in the insect world

Including the pseudoscorpion

A miniature predator
always on the prowl.

It lives on a diet of book
lice, another lover of paper.

The louse is k*lled by poison

Secreted by the
scorpion's claws.

Then the scorpion is
off to the next victim

Wherever it may be browsing.

Our finest museums

Also have an unknown
world of hungry organisms

And they're everywhere,
even if we never see them.

Their victims can do nothing
but stare at us reproachfully.

Mighty once, they
are helpless now.

Imagine the indignity of it.

In every museum
of natural history

Stuffed animals, long
dead, are food for the living.

In the lion's fur,
hidden from sight

The microscopic
museum beetle is busy

Admiring the taxidermist's art.

The museum beetle is a close
relative of the fur beetle

With similar tastes
but only half the size.

It loves the protein
in hair and feathers

And relishes fat and dirt.

It eats delicately,
one hair at a time.

But in the long run, it's the
scourge of every curator.

The museum beetle doesn't
limit itself to stuffed lions.

Instead, it savors all
sorts of collections.

Dried insects are
a prime target.

The museum beetle has
no respect for science.

A rare specimen is
just another snack.

A collection that took
decades to assemble

Can be ravaged in days.

Not that most of these specimens

Wouldn't have done the
same, given the chance.

But there's more here to
eat than just dead animals.

There's also a vast quantity
of other organic material.

The exhibition cases
are framed with wood...

And wood can be food,
or shelter, or both

To a wide range of organisms.

The holes signal the presence
of an army of tiny wood eaters.

Beneath the surface

You can find an endless
system of tunnels

And the creatures
that make them.

The white larvae of
the old house borer

Will stick around as long
as there's wood to gnaw.

This is the old house borer's
colleague, the carpenter ant

For whom wood isn't
food, but shelter.

It tunnels through the
wood to make its nest.

Then it carries away
the chewed wood

Leaving space in which to live.

The result is wood
destroyed from within...

Business as usual in the
cycle of life and death.

Nothing is safe in
the unknown world.

Even our own bloodstream
can be a highway for invaders.

But that doesn't mean
we have no defenses.

Within seconds of a cut

A net of threads called
fibrin slows the loss of blood.

The net forms when a
substance in the torn skin

Reacts with another
substance in the blood.

The blood coagulates
with a kind of natural glue.

The glue then forms a scab

Which covers the wound
until the skin can heal itself.

Skin cells divide
again and again

To form the first layer of
new skin beneath the scab.

Other layers are then
built up from beneath.

The most common
invaders are bacteria

One of the simplest
forms of independent life.

They come in a variety
of shapes and sizes.

They exist practically
everywhere

In incredible numbers.

There are one hundred
thousand billion in a human body.

Not that all bacteria
are dangerous.

In our intestines, they play
an essential role in digestion.

They combine with
stomach fluids and enzymes

To break down
food into nutrients.

This salad will need their help

As it makes its way
through the digestive tract.

But other bacteria are
long-standing enemies

Like the ones that
attack our teeth

Causing cavities and plaque.

Enzymes in our saliva
usually keep them in check

But if we forget to brush,
the battle may be lost.

Enemy manpower is unlimited.

These bacteria are moving
among the cells of the mouth

Swimming down microscopic
rivers in our mucus membranes.

The bacteria thrive on the
rough surfaces of our teeth

Where a toothbrush can't reach.

A single bacterium
can divide itself

Into one million new
bacteria in just eight hours.

Without our defenses, we would
never survive the onslaught.

But each of us has billions
of cells patrolling our body.

An army of soldiers often
stronger than our enemies

Working together
on the front line.

The first wave of troops
are the macrophages

Which literally
means "big eaters."

Hundreds of thousands of them

Travel through the blood
vessels and lymphatic system

Ready to attack.

With long, retrieving arms

They capture
bacteria and k*ll them.

Macrophages deal with
invaders simply by eating them.

They can tell a bacterium
from a normal body cell

By scanning its surface.

The cell's chemical
structure reveals

Whether it's friend or foe,
to be left alone or devoured.

Macrophages ultimately
eat themselves to death

Taking the
trespassers with them.

Together, millions of dead
macrophages and their victims

Make up the
substance we call pus.

A macrophage will attack
any foreign body it finds.

Here, asbestos fibers that
entered the bloodstream

Through the lungs
are marked for disposal.

Even another macrophage

Who has died in the
line of duty is devoured.

Our defender cells
are always on patrol

But some invaders

Are more difficult to
deal with than others

And some seem
nearly impregnable.

This is a virus, a tiny
piece of genetic material

Surrounded by protein.

Recreated using electron
microphotography

They're visible here as blue
dots on the surface of a cell

Only 100th the size
of a bacterium.

Because a virus can't
reproduce without a host cell

It isn't considered
a living organism.

But it can k*ll.

It forces its way
into the cell nucleus

And programs the cell to make
more viruses... Copies of itself.

This is a recreation
of the inside of a cell.

The red structures
are mitochondria...

The cell's power plants.

The yellow ba*ls are
ribosomes, which make protein.

But now, hidden among them, is
an enemy factory hard at work.

When the cell has made
enough copies of the virus, it dies

And thousands of
new viruses leave

In search of new
cells to invade.

This is that happens
when we catch a cold...

And far worse diseases.

A cell nucleus is
seen here in the middle.

Surrounding it are viruses.

The smaller mitochondria
are still working away

Protected inside
the cell membrane.

But their fate is
already sealed.

Using a unique
photographic process

We can now catch the viruses
in the act of entering the cell.

About 100 of them are
grouped on the cell's surface.

Then suddenly, as
if on a given signal

They force their way
through the cell membrane.

A few days later, they
leave in the thousands

Just as these mast cells
empty their contents.

Our most important
weapons against viruses

Are the lymphocytes.

They bombard the
enemy with antibodies...

Small molecules made of protein.

The antibodies are visible as a
corona surrounding the cell.

But as effective as
these lymphocytes are

They are no match for the
viral disease we call A*DS...

The most feared
plague of our time.

This is h.i.v., The
virus that causes A*DS.

H.i.v. Uses lymphocytes
themselves as host cells

To make copies of itself.

So the cell we count
on to k*ll the enemy

Becomes, instead, its victim.

The virus spreads, and we die.

This parasite causes another
deadly threat: snail fever.

All it takes is one
misstep in a water hole.

The parasite lives in
the stomach of a snail.

It waits patiently for
another host animal to pass by.

The parasite larvae then
leave for greener pastures

Penetrating the
skin of the foot.

Inside the blood stream,
the larvae mature into worms.

Stuck to the walls
of arteries and veins

They feed on our blood.

Here you can see the parasite's
mouth sucking up blood cells.

The female parasite is
thinner than the male

And lives attached to his body.

Their eggs are then carried
away by the bloodstream.

They leave our body in urine

Returning to the
water and other snails

Completing the cycle.

Another parasite
lives in a mosquito

And causes malaria, a chronic
and often fatal disease.

When the mosquito bites

The parasite is injected
through the skin

And into the bloodstream.

It lives among our
red blood cells

Feeding upon them and
reproducing in them.

The blood cells die and the
young parasites pour out

To be sucked up by
other mosquitoes

Which then bite other victims,
spreading the disease further.

Parasites affect
animals and humans alike.

They do more damage to both

Than any other
microscopic enemy.

This fight for survival binds
all creatures together...

Animals, humans, microorganisms.

It's just that some
battles are more visible.

The struggle to eat
or be eaten is universal...

Timeless...

Inescapable.

But when it comes
to the unknown world

We humans seldom pay attention
if we ourselves are not at risk.

And yet all we have to
do is take a closer look.

Beneath our very noses, we
can find a myriad of creatures

Like these scale bugs

Who can live their
lives in a flower pot

On a single plant.

Every inch of this
greenhouse jungle is inhabited.

The same kind of drama played
out on the african savanna

Is found here, even if the
protagonists are humbler.

These aphids are sucking
the sap from a leaf.

Here, an offspring
climbs on the back of one

With its siphon-like tubes.

That's quite handy
for these ants

Who treat the aphids like cattle

Herding them from
pasture to pasture.

The aphids are then
milked of their sap.

But this ladybug
wants steak, not milk.

It feasts upon
the grazing aphids.

And this red predator
mite isn't just hitching a ride.

Another aphid is the target
of this hover fly larva

Which literally
sucks out its life.

All that's left
is an empty shell.

The large butterfly
larva on the top

Is eyed by a land bug.

He's just waiting for the
right moment to strike.

Now he's ready...

And goes in for the k*ll.

To eat or be eaten.

It's no different from
the w*r within our body

Between viruses, bacteria,
and our immune system.

In this case, the
winner takes all.

Sometimes the battle is between
members of the same species.

These two male stag beetles
are fighting over a female.

From this unique perspective

They're as fearsome
as tyrannosaurus rex.

The combat ends with a lethal
cut in the loser's neck shield.

The winner celebrates
with the female

Waiting beside the b*ttlefield.

They mate, passing on their
genes to the next generation.

Evolution rules in the
unknown world, too.

The heart of the
winner still beats.

The fittest survive.

The sperm of the winner
helps shape the future.

Sometimes it's
animal versus animal

And sometimes
animal versus plant.

These ants have
learned to form chains

To pull together the
edges of giant fern leaves.

The result is a nest... Food
and shelter in one neat package.

The fern is helpless to resist.

This butterfly larva is
also free to do as it pleases.

But other plants can give as
good as they get, and then some.

Turnabout is fair play
in the unknown world.

This ant has picked
the wrong plant to eat.

Now he's the meal.

There's no mercy here.

Other plants have developed
less deadly defenses

Against intruders.

This digitalis leaf is really
a trap for unwitting insects

Foolish enough to land.

Each fiber has a sack
of glue at the end

A sack that bursts on contact

Much to the dismay
of these aphids.

On the potato plant,
the fibers are so long

That insects get tangled
well above the surface.

This aphid can't reach the
leaf to suck up its juice.

But other insects, like this
plant bug, have come to adapt.

Special claws allow it
to walk across the leaf.

All organisms have a part
to play in this struggle

Whether they know it or not.

A struggle in which life
itself will always triumph

Even in the face
of death and decay.

It's true in our world
and the unknown world.

The more we study them both

The more we see how
similar they really are.

The only difference
is one of perspective.

If we choose, we can see nature

Through the eyes of
a rhinoceros beetle

And be grateful
we aren't his size.

We can see the garden
as an obstacle course.

We change our
entire sense of scale

And imagine ourselves as the
worm instead of the farmer.

We can learn to
look beneath our feet

To see the small, the
overlooked, the insignificant...

Unusual teachers with
different points of view.

We can find a new
way of looking at life

One that's more down to earth.

We can even learn
more about our own past

From the unknown world.

In every pool of water
there are tiny organisms

Whose beginnings
are linked to ours

Distant relatives to the
cells that make up our bodies.

They tell us how life
developed and flourished...

Representatives of the
first primitive life forms

That led to all the
creatures on earth.

The unknown world can also teach
us how our own bodies function.

Like us, the water flea
reproduces through live birth...

A microscopic version of
our own reproductive system.

Above the eggs of
the next generation

We see her narrow
green digestive tract

And her beating heart.

The processes of
life that govern us

Can be found everywhere,
on the very ground we walk.

Sometimes we're the ant
and sometimes the beetle.

The trick, of course, is to
be the predator, not the prey.

The trick is to
live another day.

The tunnels of insects

Can provide a model of
our circulatory system...

Arteries in the soil

Making possible the
flow of nutrients.

An earthworm can help us
understand our immune system.

Inside, the same struggle
between attacker and defender.

On the forest floor lie clues
to our own digestive system.

Here, dead plants and animals
are broken down by the living.

In the soil of
just one footprint

There are millions of
decomposers hard at work.

Up above, the cycle of
life takes another turn.

A new generation must
always replace the old.

The dove may not ponder the
processes of life and death

But its fate is the
same nonetheless.

There is only one
direction in which to fly

No matter how
extraordinary the journey.

Just as life has
sent us on our way

Death awaits us all: the
mite, the dove, ourselves.

But the end of the story
is also the beginning

As insects and bacteria
turn death into life.

Flies lay eggs that
hatch into larvae.

Ants, wasps and beetles arrive
on the scene, along with others.

Watch as a process
that takes a few weeks

Is compressed into 30 seconds,
through time-lapse photography.

In 14 days, what was
once a beautiful dove

Has been broken down
by an army of organisms

Until only a pile
of feathers is left.

And yet everything
remains in a different form.

Other animals and plants

Are using the dove
to build new life.

Here, over five weeks

In the same small
patch of ground

Spring flowers grow and bloom.

And when they die

There are always
others to take their place.

The soil passes on
what it has gotten

Only to get it back
again in an endless cycle...

A cycle of water and nourishment

A cycle of day and night

A cycle of seasons.

Every day, our world and
the unknown world meet.

They meet on our teeth...

They meet in our museums...

They meet in our bloodstream...

For better and for worse.

They meet wherever we are.

And so it becomes clear

That our world and
the unknown world

Are really one and the same
and we are all in it together.