Life

Plants have a family tree ...

stretching back nearly half a billion years.

They have developed an extraordinary range of strategies to survive.

This tree is a bristlecone pine.

It's taken thousands of years to reach this size.

It has seen empires rise and fall,

kings, queens and presidents come and go,

and may have seen the sun rise more than one and a half million times.

Bristlecone pines are the oldest living things on Earth.

Bamboo is the fastest growing plant.

It will be full-grown, 30 metres tall, in just 90 days.

Like animals, plants are constantly competing for food,

striving to produce offspring ...

and battling against predators.

They will deceive ...

and in some cases they will even hunt.

We often don't notice such dramatic behaviour ...

because to our eyes, it happens so slowly.

But if time is compressed and you shift perspective ...

to the plant's point of view, their world comes spectacularly to life.

The events in this woodland can build to a view of half a year ...

in less than a minute.

Like animals, plants need food and water.

But what sets them apart is their struggle for light.

Plants must have light in order to grow ...

and will do anything to get as much as they need.

The forest might appear to be the perfect place for plants to thrive.

Yet down here on the forest floor ...

is one of the hardest places imaginable for a young plant to begin its life.

The canopy above is so thick that only a little sunlight can filter through.

For this sapling, too little light means death.

But plants on the forest floor need not be passive.

If the light won't come to them, they can go to the light.

But they still have a problem.

The light is 50 metres above them.

So they must climb.

It's much easier to use another plant as scaffolding.

But they won't get very high unless they can hold on tight.

Like fingertips searching for a hold,

this ivy's adhesive pads grip the bark.

Instead of sticking to the trees, some climbers use sharp claws.

The cat's claw creeper hooks its tendrils into the tiniest crevices ...

and hauls itself to the top.

With every metre it climbs, the light gets a little stronger,

fuelling more growth.

This tendril of a passion flower seems to flail aimlessly in midair,

but in fact it's searching for an anchor point.

Its tendril coils on itself, pull- ing the plant towards its support.

In a matter of just days, these climbers make it to the canopy.

Now, with light in plentiful supply, these plants are able to flower.

Other plants have a different strategy to find the light they need ...

in the crowded forest.

These are air plants.

They grow on the upper branches of tall trees ...

and spend their whole lives basking in the light.

But growing 50 metres above the ground does have its drawbacks.

Most plants get water and nutrients through their roots in the ground.

For an air plant, with their roots planted in the treetops,

this isn't an option.

But they have a solution.

First, the bare roots have an extraordinary ability

to soak up water like blotting paper.

The slightest rain or mist, and they absorb every drop.

They also have a way of gathering nutrients.

Their roots trap falling leaves, which eventually rot

and provide the plants with their own personal supply of compost.

Twenty thousand different plants,

orchids, bromeliads and ferns have taken up this remarkable lifestyle.

For a plant to thrive, it must not only get enough nutrients

but also the right balance of nutrients.

The soil in this water-logged bog is very poor quality, lacking in nitrogen.

But these strange plants have an ingenious strategy.

Their leaves are covered in tentacles tipped with droplets ...

of what appears to be morning dew.

These droplets give the plant its name, the sundew.

They're sweet smelling and attractive to many insects.

But they're also extremely sticky.

Mosquitoes emerge in huge numbers from the boggy water ...

and the sundews are ready.

The sundew's tentacles are living flypaper.

Struggling only makes matters worse.

With each contact, the plant tightens its grip.

As more and more tentacles envelope the prey,

the droplets spread across its body.

Eventually the insect is smothered and drowns in sticky fluid.

Digestive enzymes break down the body into a nitrogen-rich meal,

which is absorbed by the plant.

Without animal tissues, this plant would not survive.

But there's another carnivorous plant ...

that's an even more sophisticated predator.

The Venus flytrap.

Like the sundew, it makes itself very attractive,

oozing nectar across the brim of each leaf.

But any visiting insect had better watch out for these six tiny hairs.

This fly has to tread carefully.

If it strikes one hair,

it can carry on feeding ...

but a timer has been set.

A second strike in less than 20 seconds and the fly is doomed.

An electrical impulse is triggered ...

and the leaf snaps shut in just a fraction of a second.

The tips lock together like prison bars.

If the fly is very big or very small, it may just manage to escape.

But most are trapped ...

and die.

Ten days later, the trap reopens.

All that remains is a husk.

The plant has finished its meal ...

and resets itself for its next victim.

But there is one time of year ...

when the Venus flytrap needs some of the visiting insects to live.

It needs their help to be pollinated.

It sends up flowers on tall stems,

well away from the danger of the traps below.

Here, insects can feed safely on nectar.

In return, they provide a vital service,

carrying pollen from flower to flower.

But the truce is only temporary.

When pollination is over, it's back to business as usual.

80% of plant species on Earth have flowers.

Flowers have just one role,

to enable the plant to produce offspring.

Colour, perfume, nectar and shape ...

all act to make a flower irresistible.

Sunflowers grow to face the rising sun.

The warmth of the rays speeds the production of nectar ...

and this lures pollinators.

One after another, hundreds of individual florets ...

produce pollen-covered stamens.

And like most flowers,

sunflowers establish a close relationship with animals ...

in order to ensure their reproduction.

As these bees busily feed on nectar,

they unwittingly brush against the stamens, collecting pollen,

and then carry it from flower to flower.

The sunflower is fertilised.

In the sun-drenched fields of southern France,

the flowering season is a long one.

But not all plants have this luxury.

Cradle Mountain in Tasmania is blasted by bitter Antarctic winds.

To reproduce, the richea honey bush must flower.

But the delicate parts of the flowers risk being damaged by the cold.

The plant appears to have an ingenious solution.

The flower petals fuse together,

forming an insulated protective case around its stamens.

However, this creates another problem.

The flower case is so well sealed ...

that unfortunately, it also keeps out pollinating insects.

During brief sunny spells, the flowers warm up ...

and suddenly start producing nectar.

This attracts a bird, the black currawong.

It has the strength to rip open the flowers' outer casing ...

and gets its reward of nectar.

At the same time, it exposes the delicate stamens to waiting insects.

With luck, there's enough time for pollination ...

before the biting wind kills the flowers.

For some plants, the relationship with their pollinators is not collaborative,

it's war.

Butterflies, and in such numbers,

would seem to be perfect pollinators for any flower.

The sandhill milkweed blooms every spring in the sandy meadows of Florida.

It times its flowering perfectly to match the arrival ...

of monarch butterflies migrating here from Mexico.

The monarchs search out milkweed plants,

but they have something other than pollination on their minds.

Rather than collect pollen, this female lays her eggs on the milkweed leaf.

This is the only plant the caterpillars can eat.

But the milkweed has a defence mechanism.

As a caterpillar bites into a vein,

a kind of latex swells out, engulfing it.

If the caterpillar isn't quick it will drown,

or find its jaws glued together.

The plant's defence is so effective that only one third ...

of the monarch caterpillars make it through the first day.

But the caterpillars that survive grow in size and strength.

And they go for the jugular.

By carefully chewing through the main vein,

the caterpillar drains the leaf of latex ...

and cuts off its supply.

The milkweed's leaf is now defenceless and the caterpillar eats in safety,

before preparing to pupate into a butterfly.

But after about 10 days,

it becomes clear why the plant has endured this onslaught.

A newly hatched monarch ...

simply can't resist the nectar-filled cups of the milkweed flowers.

As it moves across the flower heads,

its feet slide between grooves in the petals,

where the flower's pollen sacs are waiting.

As it flies off,

the monarch's feet hook out the pollen and carry it to the next flower,

and pollination is achieved.

Although the milkweed has paid a heavy price,

in the end, it used the monarch to get its way.

Here in Dominica, there's a plant that is so manipulative ...

that it has enslaved its pollinator.

The bright red structures of the heliconia ...

are actually modified leaves.

These are its flowers.

They may be small, but they play a very important role,

keeping nectar well-guarded at the very bottom of their long stems.