The Secret of Life on Earth Page #2

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One more relationship between the

plants and animals can be found here.

After pollination, the flowers

are transformed into fruits...

...succulent and often colorful,

they have evolved to be eaten.

Here, wild figs attract

large fruit-eating mammals...

...known as flying foxes.

While the fruit's

fleshy part is digested...

...the seeds will pass through

the animal's body to be dispersed...

...and germinate where they fall.

This is very effective

for dispersing seeds...

...and so creating

and regenerating forests.

Each seedling will struggle

to become a fruit tree...

...and compete for a place

in the sunlight.

Fruits and berries were an important

survival food for our early ancestors.

But more crucial

to human development...

...were the seeds of another

special group of flowering plants...

...which provided the staple food

of grazing animals: the grasses.

Most plants grow from the tip,

but grass leaves grow from the base.

So after they have been cropped

by grazing animals...

...the grass will continue to grow

and make more food.

All grasses and sedges are flowering

plants. lt's easy to overlook that.

No need for insects.

Grass pollen is carried by the wind.

When the seeds are set...

...they contain a nutritious substance

which gives them a good start.

Grind it up and it becomes flour...

...a basic human food

that can be stored for months.

The wild grasses that we know

as rice, oats, barley and wheat...

...were the key to the growth

of human civilization.

What drives the combine harvesters

is energy from the sun...

...processed and stored...

...in billions of microscopic marine

plants in prehistoric times...

...as oil,

one of the so-called fossil fuels.

Another fossil fuel is coal...

...the carbonized remains

of some of the earliest forests.

lt provides more than 40%

of the world's industrial energy.

And it takes energy to operate

the great thrust into the depths...

...where the prized black seam lies.

Fossil fuels, coal and oil...

...contain energy which can

be released so easily by fire.

ln 1 991 , the Gulf War focused

our attention on what happens...

...when nature is wantonly put

into reverse.

Originally, when plants first gathered

this energy from the sun...

...carbon dioxide was used and oxygen

given off to enrich the atmosphere.

Now, fire uses up oxygen...

...while carbon gases

pour back into the air.

Less violently, it goes on

in peacetime too.

Modern transport relies

on the burning of oil.

The carbon gases discharged

by city traffic and industry...

...build in the atmosphere and prevent

the release of heat by radiation...

...thereby causing

a greenhouse effect.

Other harmful chemicals

attack the ozone...

...which shields us

from ultraviolet rays...

...damaging to human skin and also

to the plant life of the oceans.

Trash, garbage, litter.

The dead end of life.

What is biodegradable is transformed

into a new life cycle...

...but mankind has introduced

the non-biodegradable...

...the junk outside

nature's regeneration...

...which poisons land and sea.

For the first time, a single species,

the human species...

...is threatening

the life-support systems.

We have broken the green contract.

But we are learning

to be less wasteful.

As the world's resources shrink,

we are recycling more and more.

This factory already uses 30%

wastepaper.

Soon it will recycle 60% waste

into new paper.

We are also learning to capture energy

without burning fossil fuels or timber.

Besides nuclear energy,

there is tidal power...

...solar panels, wind power.

We can harness the elements.

Our space-age technology can monitor

the damage we are inflicting.

Satellites report the frightening speed

of loss of vegetation...

...particularly in the rainforests.

This is a stretch of forest in Brazil,

about 1 00 miles across.

Forest clearance and roads

are clearly visible.

Three years later, the view provides a

grim record of the rate of destruction.

Time is running out

for research scientists...

...at work in the canopy

of a threatened forest.

Locked away in the rare plants

and insects the scientists collect...

...are secrets, perhaps, of medical

cures still to be discovered.

Our heritage is a pool

of genetic material beyond price.

This periwinkle comes

from the forests of Madagascar...

...not very important, we might think.

But now it is cultivated

and harvested...

...to make a drug used

to treat leukemia in children.

Any species we exterminate

may be an opportunity lost.

Lost forever.

By discovering how plants

and animals relate...

...we can enrich our

own understanding of life.

The rainforest shows us that true life

sustains itself...

...within the available resources

that it can recycle perpetually.

Living in harmony with nature

instead of abusing and degrading it...

...may demand a change in our habits,

but it will bring new benefits.

Some of our world's most beautiful

sights are under the sea.

Even these are no longer denied to us.

lt seems to be a natural human desire

to make contact with wild animals.

This desire is gratified each day...

...for visitors to a remote beach

in Western Australia by wild dolphins.

Oh, yes. He's so beautiful.

You wanna step out, young man,

and feed this dolphin?

They're encouraged with food...

...but the dolphins do seem to enjoy

contact with humans...

...as much as the humans enjoy it.

She's saying hello again.

She wants some more dinner.

Know what her name is?

What?

Our world has developed

over many millions of years.

What gave it stability

and increasing variety...

...was an unwritten contract

between plants and animals...

...acknowledging

their interdependence...

...within a system nourished

entirely by the sun.

But we can no longer take for granted

the age-old rhythms of nature.

The growth of human knowledge has given

us a decisive influence everywhere.

From the depths of the oceans...

...to the sky's final, delicate skin

of our atmosphere.

lt is our actions which will change

the world for good...

...or for evil.

ln the sheer joy of our existence,

we must love and cherish...

...those delicately balanced forces of

nature enshrined in the green contract.

They formed the rules

of the created world...

...before we joined the long march

of evolution.

They hold the secret

of our life on Earth.

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