"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." "ORIGIN" "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." "(GRUNTING)" "Giant tortoises." "(GRUNTING)" "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." "Millions of years ago, Galapagos was born of fire." "An eruption deep under the Pacific spewed lava from the sea floor." "Layers of rock built up towards the surface over several hundred thousand years." "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." "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." "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." "Marine biologists, led by Stuart Banks, are asking why it is that Galapagos is so rich in wildlife." "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." "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." "It's the smallest of the whole penguin family." "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." "Subtitles by Red Bee Media Ltd"