National Geographic: Rhythms of Life (1995)

[bunniefuu]

From the first dawn of creation

to the end of time

our world, our lives,

and every living thing

are attuned to a cosmic song

a celestial cadence

of light and dark

of ebb and flow

of heat and cold

all set into motion by the epic

dance of the sun, moon, and earth.

These are the rhythms of life itself.

Before there could be day or night

before there was a spring or fall

a star, our sun,

had to flare into life.

From the seething stuff of stars,

over time, the planets of

our solar system took shape.

Four billion years ago, or more,

one such place was born

the planet called, Earth,

our home.

But for nearly a billion years,

it would be a home inhospitable

to any form of life

a red and angry globe

a churning mass of fire, poison gas,

and molten rock

At the core of the planet

raged an inferno.

For thousands upon thousands

of centuries,

this infant planet suffered the

violent pains of growth and change,

as it formed and reformed itself.

From the very beginning,

the earth knew night and day.

But a night and day

not like any we know now.

Fueled by the forces of creation,

the earth raced through

its daily cycle,

spinning five times as fast

as it does today.

A few brief hours of starlight.

A few brief hours of sun.

Day followed night at a dizzying pace.

Earth and sun were not alone

in their orbits.

But cosmic visitors

rarely came to stay

until one cataclysmic encounter

transformed the heavens

and earth forever.

One theory tells of a cosmic accident

a huge asteroid

on a collision course.

It may have been the birth of the moon

and so many of

the rhythms of life.

But first, the moon would have been

a cloud of fragments,

circling the planet like

the rings of Saturn

before coming together into

a huge, barren satellite.

Too small to hold a

protective atmosphere,

the moon itself has long been

bombarded by debris ever since.

Without wind or rain

to smooth the scars,

its face bears everlasting witness to

the violent nature of outer space.

On the earth below,

an atmosphere was brewing from endless

clouds of poison gasses

and water vapor,

expelled from beneath the crust.

Closer to the sun, the precious water

might have boiled away.

On a colder planet it would be

locked into eternal ice.

But on the earth,

water vapor condensed

falling back as rain upon the land.

And so the first oceans were born.

Over millions of years,

the seas rose to flood the earth.

But these were not the cool,

life-giving waters we know today.

The primal atmosphere provided

little protection.

It had no blanket of ozone

to filter out lethal radiation.

Virtually unobstructed,

the sun's unforgiving rays seared

whatever they touched.

Much closer than now,

the moon also played a violent part,

tugging at the seas with a force

countless times greater than today.

The first tides were mountains

of water, miles high.

Torn by sun and moon, the surface

waters offered no hope for life.

Still, there was sanctuary below.

In the ocean, the first building

blocks of life amino acids emerged.

They incubated in water heated by

the planet's internal fires

and fed on a bubbling broth

of nutrients

straight from the heart of the earth.

But even the ocean's depths were not

safe from a cataclysmic universe.

In a galaxy still littered

with the debris of genesis,

asteroid strikes may have vaporized

the oceans, laying the seabed bare.

More than once, life on earth

may have been snuffed out.

Yet the fire and rains of creation

kept their hold on earth,

and the oceans rose again.

Life has proven stubborn here.

Some three billion years ago, as the

earth cooled and calmed once again,

new forms appeared, the heralds

of life as we understand it.

In quiet, sheltered pools,

algae spread.

Colonies of single-celled organisms,

they thrived off abundant sunlight

and carbon dioxide.

And in their waste they left behind

oxygen, the precious breath of life.

This was the birth of photosynthesis,

a new, life-giving cycle

that transformed the earth.

For countless millennia,

algae flourished in the brief days

so bright with sun.

And now the cosmic rhythms

were changing.

Gradually, the moon and its tides

slowed the earth's mad spinning,

and the forces that bound planet and

satellite together loosened their hold.

The moon retreated to

where she stands today,

still slipping imperceptibly

away over time.

With the moon more distant,

the tides fell.

Calmer waters bred more algae

and more oxygen.

And with the oxygen came ozone,

protection from the sun's

most lethal rays.

At last, the stage was set

for the next phase of creation.

Like the fire of a new sun, the spark

of new life appeared in the waters.

Still just single-celled plants,

but organisms far more complex

than any that had come before.

Within each was a genetic code

that reflected the rhythms

of earth and heaven,

a biological clock

to guide their lives.

Daytime would be the time

to feed on the power of the sun.

Reproduction would be saved

for the shelter of night.

Millions of years later,

this clock still synchronizes almost

all life to the very spin of the planet.

From the depths of a steep-walled

lagoon

in the South Pacific island of Palau,

a herd of underwater farmers

rises to meet the dawn.

A swarm of jellyfish,

tens of thousands strong.

Without eyes, the jellyfish do not

use the light to see.

They need it to grow their food

gardens of brown algae

that flourish within their

transparent bodies.

Denied sunshine,

they would starve.

As the sun arcs overhead,

shadows of the surrounding walls

darken the surface of the lagoon.

Just below, the jellyfish ferry their

microscopic passengers,

keeping them always in the light.

When the sun sinks,

so do the jellyfish,

dropping down to the ocean floor

where the algae can find their own

nourishment.

Even without sight, the jellyfish will

know when the sun returns again.

In the surface waters of the oceans

most creatures take their cue

to feed or rest

from the rhythm

of light and dark.

Now, members of the night

shift hurry to take the stage.

Roused by light-sensitive cells that

announce the return of darkness,

these prickly browsers

set out to graze.

Sea urchins find their prey

and their way around

by touch and by taste.

Each night clouds of plankton rise

from the deep to feed

drawing out the coral who fish

the waters with feathery nets.

A few, sharp-eyed fish operate by

sight in the dim light before dawn.

Like a cat in the dark, the lionfish

can pick out its prey.

The lionfish will slip into a crevice

to hide from the daytime;

eyes sensitive enough for half light

may be too delicate for bright sun.

Daybreak brings the morning

rush hour to the reef.

Far more complex than jellyfish

or sea urchins,

most fish depend on sight to survive.

Without the sun they are virtually

blind to navigate their world,

to find their food,

or signal to their kind.

A kaleidoscope of colors enhances

the play of daylight on the reef.

For the fish, stripe and hue holds

clues and communications,

helping them to identify mates,

predators, and prey

in the busy rainbow of the reef.

Trailing twilight in its wake,

a manta ray flies in,

to harvest plankton when again

they rise with evening.

Sunlight fades, taking with it

the world of color,

and the day shift streams off the

reef for the safety of deeper water.

And once again,

the great earth wheels round.

The line between light and darkness

divides those that live by land

as well as the creatures of the sea.

And even the land and sea themselves

breathe with the rhythms

of day and night.

Given off by day,

water vapor now rises, cools,

and condenses in the night air.

From earth, through plants,

into the air,

and back to the earth again

the endless cycles of replenishment

and renewal.

The plants of this Australian

rain forest

have been in tune with the rhythms

of the sun for eons.

Here, an acacia tree wakes up

and stretches for the dawn.

Like a sundial in the trees,

the play of light and shadow

across the forest floor marks

the turning of the planet.

A shifting pool of light holds

treasure for plants and animals alike.

Sunbathers under the leafy canopy,

many plants collect much of their

energy during brief interludes of light.

A boastful bird takes this spotlight

for a stage.

In the dark, his finery is invisible,

meaningless.

Only by day can the male riflebird

capitalize on his gaudy attire.

His appearance, like a feathered,

black-and-white rose,

has been calculated by evolution to

entice females to his side.

A vibrant, sunlit display,

all about sex,

as crisp as the snapping of a fan.

The last hours before sunset often

inspire a flurry of movement.

Once the sun fails,

most birds will lose their powers

of sight and of flight.

They gorge in preparation

for the fast to come.

Color and flair are an advertisement

for plants too.

Their brightly hued fruit

attracts birds,

and with the feast the cycle of life

and rebirth will continue.

For after eating,

the birds will spread the seeds

of new plants far and wide.

While most creatures of the air

depend on the bright of day,

others like fruit bats, are tuned to

more nocturnal rhythms.

All day they had been invisible,

sleeping in the shadows,

saving their energy against

the hot sun.

Now twilight signals to them,

a silent summons.

The bats scramble and take control of

the air the birds have left behind.

Millions crowd the sky,

ever graceful, never colliding.

Foraging in darkness,

the bats have turned to senses

other than sight to find their way.

They navigate the night by sound,

until they find a likely spot

for a meal.

By moonlight,

plants need a different lure

to attract visitors' perfume.

Little is more savory to these bats

than the scent of

ripe blossoms and fruit.

And once they take their fill,

like birds,

they carry seeds everywhere they fly,

assuring the future of

their favorite foods.

The rising moon offers

a gentle promise,

cooling relief from the heat

of the day.

And many creatures bide their time

until the evening hours.

Other mammals have also learned

to maneuver through the midnight air,

like Australia's sugar gliders.

With their built-in parachute,

a sugar glider can span the length

of a football field.

It may seem a bold leap of faith,

but they're only following

family footsteps.

By smearing their scent

upon the branches,

they blaze invisible trails

for their kin to follow.

Their search for insects, sap,

and nectars

carries the gliders into the night.

Like bats, they survey the dark

with sensitive noses.

This evening harvest keeps

these squirrel-like creatures

safe from the predators of day.

Instinct warns them to be back

in their nests by dawn,

before sharp-eyed hawks and eagles

take to the skies.

For millions of years,

mammals were the masters of the night.

In prehistoric days dominated by

dinosaurs, smaller, warm-blooded animals

took advantage of the relative safety

of the darker hours.

But the days when mammals were forced

to hide from the coning of the light

are long since over.

Now, in rain forests round the world,

near the top of the evolutionary ladder,

you'll find agile tree-toppers ready

and willing to celebrate their place

in the sun.

These proud primates,

central American howler monkeys,

inaugurate each day

with a morning chorus,

staking their claim to the trees

and life at the top.

Higher still cling their smaller

cousins, the spider monkeys.

With few natural enemies

they rule the roost.

Grasping hands and feet give them

confidence to live life out on a limb.

And evolution has given them

a whole new point of view

stereoscopic vision.

It gives them the ability to judge

distance precisely an.

And invaluable skill

when hurtling through the treetops

Somewhere deep

in the prehistoric past,

the human line diverged from

that of monkeys and apes.

And even if we no longer get to

work vine to vine,

we still share common genes

and heritage,

and an attachment to

the daytime hours.

It's programming imprinted on us both

by the ever circling sun

and its cold celestial partner.

Lunar rhythms cast long shadows

over daily life on earth.

Though the mile-high tides of creation

have shrunk to swells of mere feet,

the rise and fall of the oceans

still exerts a powerful force.

From 240,000 miles away,

the moon's pull wields power

enough to carve the coastline

and buoy up the polar ice.

Four times a day,

the sea scours the coast,

always retreating, always returning.

It's a force both destructive

and life-giving.

Many creatures thrive here, on the

shifting boundary between sea and land.

On gentler shorelines,

each time the tide retreats,

it leaves behind a feeding ground

replenished by the sea.

The lull between high tides

sees a race for survival,

a race against the lunar clock.

These scavengers must

feed their fill now.

Sand-bubbler crabs pick food

from the net of the sand,

sorting out trapped particles of

seaweed and other plants.

They leave behind

delicate spheres of sand.

It's a temporary testament

to their labors.

Combing the territory

around their burrow,

they scar the sand with their tracks,

each lone scavenger attending to

its own hunting ground.

Other creatures march boldly forward

with the strength of numbers.

Soldier crabs sweeping the shore

in battalions.

Mostly males,

they work together by the hundreds,

exhausting each plot of land

before moving on.

An army of crabs,

a living tide of hungry hunters.

But no army can defend against

the moon, and they know it.

The crabs' parade grounds

will be deserted

by the time the tide marches back

to claim it.

As water replaces land, those

that can, take to the air.

Here the moon is mistress.

She sets the rhythm of life

at all hours,

low tide is time to eat;

high tide, the time to rest.

Wading birds make the best of life

at the shore.

Stilts for legs let them follow the

waters' edge as it ebbs and flows.

Beyond the sandy shore,

the tide floods up

through the clutching fingers,

the roots, of mangrove trees.

Here in the muddy flats,

the fiddlers dig their wells,

preparing for the tide's return.

For these engineers,

the last act before the flood

is to batten down the hatches

with a fresh cut plug of mud.

They'll wait out the flood submerged

in underground burrows.

Like wading birds, the mangroves

will weather the waves on stilts.

The rhythm of the tides beats

both night and day.

For whenever the tide is low,

the shore's inhabitants

will come out to feed,

by sunlight, moonlight,

or in the glimmer of the stars.

Behind this constant ebb and flow

beats a second, slower tidal rhythm,

a cadence that for many,

spurs the times of mating and of birth.

This is the lunar cycle,

the month-long dance of earth,

satellite, and sun

that paints the changing faces

of the moon.

Twice each month,

the sun and moon conspire

to raise the level of the tides.

At the new moon and at the full,

the gravity of both our star

and our satellite aligns,

lifting the tide to its

greatest height.

In between,

the tides are at their weakest.

This monthly cycle of tides touches

creatures of the sea

in a place deeper then the daily

rhythms of feeding and rest.

A pair of male parrot fish swirl around

each other, jockeying for supremacy.

Their competition is a sure sign

that the full moon is on the rise.

This dance heralds the

spawning season.

When the full moon tide begins to ebb,

the females will release their eggs.

With the tug of the ebb tide,

the mating frenzy begins.

Thousands of fish, male and female,

dash through each others' wakes,

casting clouds of eggs and

sperm together into the tide.

One breed's spawn is another's feast.

Predators join the tumult,

to feed their fill on eggs.

But the spawning fish know

how to play the odds.

They have fertilized tens of

millions of eggs.

Millions will escape, pulled out to

deeper waters by the outgoing tide.

At high water, the surf storms back

over the reef,

sweeping schools of tiny fish

into the lagoon.

A silvery cloud flashing on

a watery wind.

For many, this will be

the last moment in the sun.

Trapped in quiet,

shallow waters,

they make easy prey for hunters

circling above the surface.

Moon, fish, and birds all whirling

in their own perfect harmony.

This black-naped tern lives a life

scored to the music of the tides.

On the shore, females have laid

claim to nesting sites

and some have already begun

to lay eggs as well.

While one bird minds the nest,

its mate fishes the shallows.

These seabirds time their breeding

cycle to coincide with the easy prey

washed into the lagoon

by the full moon tides.

Now is the time to eat heartily.

Soon the chicks will hatch.

And soon the moon will come

full circle,

the tides again filling the shallows

with tiny fish.

All in time to feed newly-hatched

chicks.

Although barren herself,

the moon prompts the sexual life

of many animals,

both above and below the surface.

Just after the full moon, the corals of

the Great Barrier Reef begin to spawn.

In a week, the tides will reach

their slackest point.

And over 200 different

species of coral

will launch their seed into

a galaxy of eggs and sperm.

In the still water,

there is time to drift and mix,

time for eggs and sperm

of the same species to mingle

and create a new generation.

Sea worms,

who live imbedded in the coral,

cast off their tails,

adding to the blizzard.

Writhing bags of sex cells,

the castoffs dance among a veritable

Milky Way of new life.

These celebrations are orchestrated

by the music of the spheres,

the distant dance of the solar system.

Like the moon,

the sun also sings to us

in rhythms slower than

the everyday of rise and set.

Around this star journeys the earth

at a stately, year-long pace,

initiating the cycle of the seasons,

ferrying winter and summer

from south to north, and back again.

Even at the poles,

the sun makes her mark

with the shimmering aurora,

the wake of the solar wind.

In the Antarctic,

the cycle of the seasons becomes one

with the rhythms of the day and night.

Here six months of sunlight are followed

by six months of dark and dusk,

summer followed by winter.

Even in the extremes of Antarctica,

life is tenacious.

Throughout the dark

of the polar night,

each male emperor penguin

guards a single precious egg.

Hardly moving, never hunting,

they've not eaten since autumn.

In temperatures reaching 70 below,

winds up to 50 miles an hour,

they huddle together for warmth

and protection, and wait for the sun.

In a land where evening lasts for six

months, dawn can seem to take forever.

Finally the penguin chicks will hatch,

and like their fathers,

they will be desperate for food.

Males can lose nearly half their body

weight during this incubation time.

But help is on the way.

Mother's coming.

For months, they have been feeding

on the bounty of winter seas.

Nature's biological clock is

at work here, too.

The females seem to sense the exact time

to leave for the nesting grounds,

for they have a huge trek

across the ice to get here.

Even tired and hungry, the males

may be slow to give up their chicks.

Temperatures on the ice

can be k*lling.

Babies left exposed too long will die.

The guard successfully changed,

males are free, at last,

to head to the sea,

and to feed.

The chicks will be fed by mother

and kept warm until the sun

climbs high into the sky.

Ever and always,

the coming of summer

depends on the swing of the earth

as it circles the sun,

and as it reels on its tilted axis.

As the earth spins through the year,

the sun's strongest rays sweep across

the globe, bringing change in its wake.

Near the equator,

the angle of the sun's rays

varies little through the year.

Still, it's enough to give the tropical

regions their own seasonal rhythm,

the cycle of drought and flood,

the wet and the dry.

September in Australia.

The air above the baking northern

plains rises with the heat.

With it comes cloud banks full of

moisture, pulled inland from the coast.

The wheeling clouds bring drama,

but no relief to a thirsty land.

They are not rainmakers,

but sky painters.

The monsoons are still months away.

Even so, deep in their nature,

plants and animals seem

to feel the rains coming.

A new cloud stirs-plant suckers rising

with the rhythms of the spring.

What looks like the bark of a tree

breathes with life,

a frill-necked lizard,

waiting out the drought.

For months it rations energy,

moving little, feeding less.

Wallabies are rainy day lovers.

While they wait for the wet season,

males joust for the chance to mate.

Now even the plants take a chance

that the drought is on the wane,

greening with fresh leaves.

Soon, all their preparations

will be rewarded.

The wet, the season of the rains

is coming at last.

From deep in their shadowy castles,

colonies of termites rouse

to the reveille.

One storm brings another,

a rain of flying termites.

They take to the air by the millions,

in the quest to found new colonies

in rain-softened soil.

And as always, the rhythms of one

life mesh and turn with others.

Wide-eyed possums in the trees,

and bandicoots on the ground below,

end the fasting of the dry months

with a welcome late-night feast.

At the end of their migration,

termites shed their now useless wings.

Many will fail to ever find a mate

and burrow safely underground.

With the coming of daylight, there

will be others to join the feast.

Conservative no more, the

frill-necked lizard becomes a glutton,

storing up protein for

the breeding time to come.

But it may face competition

for the spoils.

Undaunted, the lizard takes his fill,

working alone.

The green ants do it differently,

working together in groups.

Both species tend to the harvest with

a persistence that is single minded.

Little disturbs the teamwork of ants.

They scavenge night and day,

dry or wet.

At the peak of the rainy season,

the storms are now more than

most animals might care to see.

But their only choice

is to wait the cycle out.

Like the rhythm of the tides,

the rolling seasons of wet and dry

shape life for every plant

and animal on this land.

Not one of them can stop the rain,

or light the black of night,

no more than the fish command

the seas to rise and fall.

One creature only dares

to fight the night

the bold and restless dreamer

hunter, builder, man.

But even in our cars and castles,

we submit to the rhythms of the earth.

Dawn and the sun summons us to work.

We swarm like schools of fish

to the cities,

flashing to feed and mingle

on the reef.

Beneath the canopy of urban forests,

we hunt and gather

what we need to live.

And dusk still calls us home again

a flock of birds

returning to the roost.

But over the millennia,

we have learned

how to fight the darkness

with fires of our own design.

We strain against the boundaries,

reshaping the border

between night and day.

We create our own complex orbits,

drawn to the sky

and the distant heavens.

Yet finally,

for all our powers and wisdom

man is still just a player

on a vast stage.

Hour by hour, year by year,

the cosmic clock

marks our time on earth.

Seasons turn.

Tides rise and fall.

One generation passes on to the next.

Nothing lasts forever,

not even the stars themselves.

Night by night,

over countless years,

the earth will slow on its axis.

The moon will drift yet further away.

Days will lengthen,

the tides grow quiet.

Billions of years from now,

the seemingly endless cycles

will come to a close

as the fires of creation at last

consume the sun.

Yet ours is but one small star,

in one tiny galaxy,

in a universe beyond measure.

Perhaps there are other

rhythms of life,

unseen by our eyes,

yet as grand and majestic

as our own.