Original subtitles

In the vastness of the Pacific, there's a place unlike any other.

Enchanted volcanic islands that are home to a remarkable

collection of animals and plants.

Here, evolution is proceeding with spectacular speed.

Black lizards that swim in the ocean

and spit salt from their noses.

Penguins, thousands of miles from Antarctica.

And an abundance of unique plants.

Some animals are tiny,

and some have only just been discovered.

This is a place of wonders.

Galapagos.

Islands born of fire,

with inhabitants that have

transformed our understanding of the whole of life on Earth.

In a lifetime spent making natural history films,

I've been to many wonderful places

but none more extraordinary than here, the Galapagos Islands.

These have been called nature's greatest experiment, for here,

life has evolved in isolation and produced some extraordinary results.

The extraordinary creatures of Galapagos astounded

Charles Darwin when he first came here 200 years ago.

They led him to formulate his revelatory

theory of evolution by natural selection.

And now, 200 years later, there are still mysteries to be solved

and new discoveries to be made.

Teams of scientists are investigating unexplored regions of

the remote islands and discovering hitherto unknown animals.

On the peaks of its volcanoes,

inside networks of immense

tunnels within the lava flows

and in its crystal clear waters.

Among a population of giants,

and in the magical world that is revealed by the microscope.

New technologies are enabling scientists to investigate

the workings of evolution in new ways

and producing insights that would have astonished Darwin himself.

Today, we know a lot more about these islands.

The discovery of new species,

long-term studies extending over decades,

have given us new perspectives not just on this place,

but on the process of evolution worldwide.

The islands lie 600 miles from the coast of South America

and straddle the equator.

There are 16 of them, and a multitude of small islas,

all separated from the rest of the world by the huge expanse of ocean.

The biggest island is Isabela.

Lying in the centre of the group, it has a strange seahorse-like shape.

That is because it originated as six separate volcanoes which

eventually fused into one great island.

The most remote of them is Alcedo.

Its vast crater is four miles across.

The huge steep-sided walls,

still smoking with jets of volcanic gas and steam,

make this one of the most isolated places in the Galapagos.

And it has become a sanctuary for one of the islands'

most spectacular inhabitants.

Giant tortoises.

There are thousands of them.

These are the extraordinary creatures that gave their name

to the islands.

Galapagos in Spanish means tortoise and here,

in the pit of the volcano Alcedo, they've assembled in quite

some numbers to wallow in the warm volcanic mud.

A big one can weigh as much as a quarter of a ton.

They live for up to 100 years or more, which makes them

amongst the most long-lived of all vertebrates. And being reptiles,

they get their energy by basking in the sun.

But their bodies are so big that once they are warmed up,

they can carry on browsing for quite a long time.

The existence of creatures like these,

so far from the nearest continent, poses many questions.

How, for example,

did these enormous beasts get to the islands in the first place?

But perhaps the most extraordinary thing about the Galapagos

tortoises is that they're not all the same.

Different islands have different kinds.

In their heyday there were 15 species.

They seem to have appeared in an evolutionary blink of the eye

in this tiny cluster of islands.

And the tortoises are not alone in this.

Almost every animal and plant in the islands has a similar story.

The animal colonists began to change from the moment they arrived,

driven to do so by the harsh volcanic landscape around them.

There is evidence all around these islands of their direct

connection with the furnaces deep in the Earth's crust.

But it wasn't until recently that we

realised just how close those connections are, here.

Underneath the section of the Earth's crust

on which Galapagos sits, there is something extraordinary.

A gigantic column of super-heated molten rock rising upwards.

This hot spot is immense.

At least 60 miles across.

It extends downwards for 1800 miles

and connects the islands to the very centre of the Earth.

This image, based on the very latest seismological data,

shows the hot spot from underneath the crust.

This is the source of the islands' volcanic activity.

It began to build the Galapagos four million years ago.

A series of islands emerged from the sea.

Today, there are 16 of them, all of which are volcanoes.

Most are now extinct and the oldest are crumbling into the sea.

But the newer islands are still active and spitting fire.

The youngest is Fernandina.

It rose from the sea just 500,000 years ago.

And because it's still active,

the lava fields that cover it are still unweathered.

And here, in this desolate, barren place, we can see how the

ingredients of a great natural experiment came together.

Fate placed these islands in a unique spot on this planet.

They lie plumb on the equator, with its year-long warmth

and sunshine. But perhaps, more importantly,

they also lie at the crossroads between two competing winds.

The southeast trade winds blow up from South America

and the northeast trades come down

from the Caribbean and Central America.

These two winds are the lifeblood of the Galapagos.

They carried the earliest settlers to the emerging volcanic islands.

seeds falling from trees in south and central america

blown across hundreds of miles on ocean.

most lost in sea.

of those few that reach the islands,

many fell on steroid baking hot rocks, but just few who's luckier.

this extraordinary species is related to dandelions.

and its far away to grow where there is neither soil nor rain.

a wind blown seed arrives, and dropes in crevice in the lava.

Moisture collects and cause it to germinate.

with its tiny leaves that managed to collect more moisture.

and the infinite small quantities of nutrients that moisture from the skies might contain.

some of these leaves may look dead, and indeed they are.

the plant is deliberately shutting theme.

it's ensuring that nothing it produces is wasted, it's creating its own soil.

and eventually after 80 to 100 years, it produced this.

Scalisia, it seems to grow straight out of naked rock.

after such a tiny beginning, this extraordinary plant has gone from strength to strength.

today, whole forest of giant dandelion, blanket the high slopes of the island.

but some plants use a more direct mode of transport, than merre gust of wind.

A bird

The Albatross is the king of long distance flight

it spends most of its life on the wing

But each year it lands somewere, to breed and rise a chick.

The appearance of new island in the middle of the ocean, provide Albatrosss with new nesting site.

And oftenly huge birds broughts hitchhikers.

Seeds stock to their feets, and in their feathers.

They may even have give hitchhikers, a head start in life with a nice packet of fertilizer.

So gradually, small patches of vegetation begin to appear on the newly emerged islands.

The seeds of most trees, are too big to be cared far by birds or the wind.

But those that habitually grow along the coast, can use different form of transport.

This is the seed of Mangrove,

And when it falls, it drops in the sea and floats.

This part of it is green,

So can make food just like a leaf can, and the seed can remain made it at sea in life, for a very long time.

But eventually it may float into an estuary,

And then water is brackish, and less buoyant.

So the heavy end of the seed falls, and it hangs on the water like this.

And it's tip, and maybe low tide,

Trails into the mud, and sticks.

And the Mangrove has implanted itself.

This trees are very effective colonists of newly formed islands.

The young seedlings quickly established themselves,

Their tangled arching roots form a grid, wich slows down the tidal water searching through them,

cause in it to drop sediments as mud.

At low tide, all kinds of creatures come out to scavenge among the roots,

And when the tide is high, other creatures swiming to find a shelter.

The water's arround the tangle roots, serves as nest for many species of fish.

So plants created habitats

where animals could survive both in water,

and out of it.

Some of the very first animals here were spiders.

There are some 150 different known species of them

in the Galapagos today,

and they travel in a way that is all their own -

they balloon.

The hatchlings of many species use specially adapted silk.

A spiderling climbs to the tip of a leaf or a twig.

There, it produces a thread of silk from the spinnerets

at the end of its abdomen.

This 3D electron micrograph shows that this thread is actually

two filaments that are stuck together.

It's flattened like a blade.

The slightest wind will catch it.

Once a gust is strong enough,

the spiderling lets go with its feet and is carried up

and away.

Some can float up to an altitude of several thousand metres.

And up there in the trade winds millions of years ago,

and doubtless many times since,

some of them made the 600 mile journey to the Galapagos.

And spiders were not alone, floating through the skies.

Many different forms of life were brought

here by the wind from the South American continent -

seeds, pollen,

viruses, bacteria,

algae and insects.

Insects, of course, are extremely important in most ecosystems.

They pollinate plants

and they're food for many other kinds of animals.

The species that reached here are nearly all the smaller

South American species.

The bigger ones were too heavy to make the journey.

But one quite large insect did so.

And its arrival started a new phase in the colonisation

of the Galapagos.

It was a beetle.

Beetles are nature's great recyclers.

They chew up organic matter and that helps to create soil.

Beetles have sizable bodies but also large wings.

That made it possible for one species to make

a wind-assisted passage to the Galapagos.

Once here, these beetles began to change.

Later generations had smaller wings.

In fact, some Galapagos beetles lost their wings altogether.

Those individuals with smaller wings were much more likely to stay put.

That is because the big wings that brought the beetles here can

equally well carry them off again.

Insects and plants that were brought together in this very

arbitrary way now began to establish new relationships.

But one, in particular, had a very far-reaching effect.

Sometimes, surprisingly perhaps,

flying insects arrived in the Galapagos not by air, but by sea.

Inside this piece of wood,

there is a nest of a little carpenter bee, whose ancestors

must certainly have arrived here in that way.

This unimpressive little creature was to be of great help to

many of the newly-established plants.

It fed on their nectar and pollinated them.

Carpenter bees are still the main pollinators on the islands.

And the plants have adapted accordingly.

Nearly all the flowers on the Galapagos

are now either white

or yellow.

Those are the colours preferred by the carpenter bees,

so there's no point in being anything else.

So, land plants flourished.

In the sea, there was another factor that helped the colonists.

Amazingly, it came not from the nearest land, South America

but from 8,000 miles away,

across the Pacific in the other direction, to the West.

From the tropical rainforests of New Guinea.

here, there are heavy downpour of rain every day

The rain washes nutrients from the forest soil,

down streams into rivers

and finally, into the ocean.

And there, swept up by the currents,

they're carried across the Pacific to the Galapagos.

They travel not near the surface

but in the depths, by a cold water current.

It's one of three that converge on the islands.

Another comes from the Panama Basin,

and yet another originates near Peru.

This convergence of currents has had a remarkable

impact on life in the islands.

Scientests, led by marine biologist Stuart Banks,

are today investigating their effect

Well, Galapagos is unique in the sense that it's

a system in the Tropics, it's lying right on the equator under

the strong equatorial sun and these are usually systems

which are considered to be deserts for productivity.

But Galapagos is different.

There's a unique confluence of currents and most importantly,

a submarine undercurrent called the Cromwell current,

and these undercurrents are bringing micronutrients up into these

sunlit waters.

The Galapagos Islands in the open Pacific

lie in the path of these converging currents.

They deflect the cold,

nutrient-laden waters upwards to mingle with the warm water above.

This mixing creates ideal conditions for a vast

community of floating microscopic plants.

Phytoplankton.

Each tiny organism is only a few microns across

and invisible to the naked eye.

Yet these specks of life underpin the whole Galapagos ecosystem.

And here the fertilizer from New Guinea enables them

to hugely increase in both variety and number.

Scientists have now discovered that the islands themselves provide

the phytoplankton with something that is crucial for its growth.

A vital life-enhancing element -

iron.

Now the undercurrent which hits the western side of the archipelago,

it's a bit like, imagining, pointing a hose against the side of a wall.

It forms filaments that physically spread around the archipelago

and up into the surface.

And it's thought that it's the abrasion

and the leaching against the volcanic platform

of the islands which is bringing iron up into the surface waters.

So, thanks to that unique situation,

you tend to get these huge phytoplankton blooms and this

is literally millions of these tiny organisms coming together.

This extraordinary image, based on satellite data,

shows how blooms of phytoplankton grow and shrink over the seasons.

These astronomic numbers of microscopic plants support

another vast community.

Microscopic animals -

zooplankton.

Here, under the waves,

there is a living world of extraordinary complexity and beauty.

All these tiny creatures are dependent on the rich

blooms of the phytoplankton.

Some graze on them.

Others graze on the grazers.

Many equally extraordinary creatures feed on the rich soup.

From small crustaceans

and juvenile jellyfish,

to the young of many fish.

These tiny animals and plants, in turn, support shoals of larger

fish that swarm in such numbers and variety that they make

the Galapagos waters among the most diverse of all marine ecosystems.

Many extraordinary creatures feed directly on the plankton itself.

Garden eels are quite small,

some 15cm or so long.

But much bigger fish also feed on the plankton.

They, in turn, are food for hunters.

Among them, the Galapagos shark,

a relative of the tiger shark.

And scalloped hammerhead sharks, which today congregate

here in numbers that are unequalled anywhere else in the world.

Huge schools of females are often surrounded by an outer

ring of patrolling males.

No one is quite sure what's happening at these times.

It's probably part of their mating behaviour.

Many coastal species are unique to these islands.

This is the red-lipped batfish.

Its lower fins have been modified to enable it to

prowl across the seafloor.

The Galapagos sea robin can also walk

And flashes its bright petrol fins to frighten away predators

The Trumpetfish has such an elongated body that it's hard to see

so it's able to sneak up on its pray

And there are giants here too.

This is the Mola Mola, the sunfish.

It's huge,

three metres across and addicted to lying on its side at the surface.

It eats vast quantities of jellyfish.

And there are not only fish swimming in these waters, there are mammals.

Sea lions, whose ancestors originally came from the coasts of California.

The Galapagos plankton is so abundant,

it attracts some of the biggest of all ocean mammals -

humpback whales.

And rivalling them in size, the biggest of all fish,

the 20-ton whale shark.

Few parts of the world's oceans can equal these Galapagos

waters for sheer variety and abundance of marine life.

And this richness in turn has attracted a great

variety of sea birds.

Many are long-distance travellers.

The islands have become the best place in hundreds of square

miles of open ocean for many birds to rest and to breed.

The Nazca Boobies range across the whole of the Pacific

but this waved albatross lives nowhere else but here.

The male frigate bird has a pouch of scarlet skin hanging from his neck.

During the breeding season,

he inflates it to attract a mate or see off a rival.

There's also another kind of Booby -

the blue-footed.

His spectacular feet are the key elements in his courtship

display in which he tries to persuade his mate

that his really are the bluest feet around.

Boobies are superb fishermen.

Once they spot a shoal, they fly out to a height of 25 metres

and then they dive into the water at speeds of 60 miles per hour or more.

Hitting the water with such force could kill many birds

but boobies have special air sacs in their heads that cushion the impact.

Cormorants are coastal birds rather than ocean travellers

so they can only have arrived in the Galapagos by accident, having

probably been swept out to sea by a gale.

But they arrived a very long time ago

and they stayed.

Like cormorants worldwide,

the Galapagos species is a superb swimmer.

Its legs are powerful paddles.

And the body itself is beautifully streamlined.

In effect, the cormorant flies underwater

and it's certainly able to out-manoeuvre many a fish.

The Galapagos coast is a great place for a cormorant.

There are plenty of excellent nesting sites.

And there are no land predators that might threaten a bird

sitting in such a vulnerable place.

Its ancestors, when they first arrived, had wings

like any other cormorant.

But with no need to fly,

its wings over generations became smaller and smaller.

Now, they are mere stumps with a few tattered feathers.

So now, the bird can't fly even if it wanted to.

And since it's flightless,

there is no disadvantage in growing bigger and the Galapagos

cormorant is now heavier than any of its flying relatives.

With nothing to hassle it and plenty of fish in the sea alongside,

the cormorants can now concentrate on caring for their young.

And in fact, some manage to raise three broods each season.

But there is another permanent resident here whose history

is even more remarkable.

Its ancestors lived 5,000 miles away in the Antarctic.

That creature was a penguin.

Penguins are ocean-going swimmers

but a few thousand years ago some of them

got caught in the cold waters of the Humboldt current and were carried

northwards up the coast of South America and out to the Galapagos.

They could hardly have found anywhere more

different from their polar home

and in response, they changed.

The emperor penguin that lives near the South Pole stands over

a metre high.

The Galapagos penguin

is now only half as tall.

And that helps a lot in the Galapagos.

Small animals lose heat much faster than big ones.

And the penguins have developed behavioural tricks as well.

Bare feet are easily sunburnt

so they do their best to keep them covered.

And some parts of the sea around the islands are quite cool.

The Humboldt current, flowing up from the Antarctic and washing

around the western parts of the archipelago, is still quite chilly.

So, most of the penguins stay in the channel between the two

western-most islands.

And when things get really hot, they can still cool off with a swim.

They're quick to detect the slightest

variation in temperature and move around to find places where

an eddy might have brought a pleasing chill.

The arrival of penguins must be the most unlikely

event in the whole story of the colonisation of the Galapagos.

But the most important

and influential animals had yet to appear.

Not birds,

but reptiles.

Many million years ago, somewhere in South or Central America,

a reptile, an iguana,

was grazing close to the banks of one of the great rivers.

Perhaps it was feeding on floating vegetation.

Maybe it fell onto such a raft from a tree.

Patches of floating vegetation are still swept

out into the estuaries by flash floods or tropical storms.

Many are quite big,

and easily buoyant enough to support a metre-long iguana.

And sometimes, they don't break up but float out to the open ocean.

Who knows how many thousands of animals of many kinds have been

lost at sea on rafts like these, dying from thirst and exposure.

But reptiles are very tough.

They can go without food or water for days, weeks, even months.

No mammal can survive such hardships as long as they can.

And, at some point in the history of the Galapagos, the currents

carried an iguana across 600 miles of ocean to the islands.

No doubt it happened not once but several times.

And here, the iguanas settled and multiplied.

Today, there are thousands of them.

So many, and so widely distributed throughout the islands,

that they are now one of the Galapagos' most famous inhabitants.

But these are the most celebrated of all.

The ones that gave the islands their name -

giant tortoises.

Tortoises can't swim, but they can float.

And about three million years ago, one of them,

a large species from the South American forests,

was carried away perhaps by a flash flood and swept out to sea.

After weeks, maybe even months, they eventually landed on an island

and one of them, perhaps a gravid female, produced eggs.

As time passed, they spread into other islands in the archipelago.

Giant tortoises had arrived

in the Galapagos.

With this small selection of animals and plants in place,

nature's great experiment gathered pace.

Forged by fire,

fuelled by the ocean,

fanned by the winds

and seeded by a very few and very different species.

A new community was established here in the Galapagos,

and one with a very small but very oddly assorted cast of characters.

There were no amphibians. Because of their porous skin,

they are poisoned by seawater.

There were no mammals except for a small short-tailed rat.

Flying insects and seeds of plants had reached here,

brought by the wind.

But fundamentally, this was a land of birds which flew here

and reptiles which floated here.

And together, they had to make a living on this bare,

rocky island that was so crucially different from the well-watered,

luxuriant forests from which they had come.

In the next programme, we will discover how this strange,

oddly assorted cast of characters learned to colonise even the

most hostile parts of the Galapagos and to live with one another.

And how they changed in the process.

And we venture even deeper into the islands,

into places where even today,

new species are being discovered.