0:00:33 > 0:00:35When I first started making programmes,
0:00:35 > 0:00:38the origin of life
0:00:38 > 0:00:41and the structure of DNA was unknown
0:00:41 > 0:00:44The fact that continents might drift across the surface
0:00:44 > 0:00:46of the planet was ridiculed.
0:00:48 > 0:00:52Then, science was something you did in museums and laboratories.
0:00:52 > 0:00:54Today, that's very different.
0:00:54 > 0:00:58Today, scientists travel to the farthest ends of the Earth.
0:01:00 > 0:01:05As a result of their discoveries, we can now make sense of what
0:01:05 > 0:01:08not so long ago seemed baffling mysteries.
0:01:09 > 0:01:12And for the last 60 years, I've been travelling in their footsteps,
0:01:12 > 0:01:16trying to translate some of their insights into film.
0:01:42 > 0:01:44Early in my television career,
0:01:44 > 0:01:48I met the distinguished Austrian scientist Konrad Lorenz,
0:01:48 > 0:01:52who was one of the first to try and understand animal behaviour.
0:01:53 > 0:01:55He worked with geese,
0:01:55 > 0:01:57and he discovered that
0:01:57 > 0:01:59if he was the first thing young goslings saw when they hatched,
0:01:59 > 0:02:02they would follow him wherever he went.
0:02:08 > 0:02:11It was as if he had become their parent.
0:02:15 > 0:02:20He called as this process imprinting and as a result of it,
0:02:20 > 0:02:23the young continued to follow him, even as adults.
0:02:27 > 0:02:33In 1952, Professor Lorenz published a book explaining how
0:02:33 > 0:02:37he could talk to animals and, in particular, to greylag geese.
0:02:37 > 0:02:41It was called King Solomon's Ring, and this is it.
0:02:41 > 0:02:43And I was given the job of interviewing him
0:02:43 > 0:02:45on live television about it.
0:02:45 > 0:02:49And I started by saying, now Professor Lorenz, I understand
0:02:49 > 0:02:51you can speak greylag goose language,
0:02:51 > 0:02:53and I actually have a greylag goose here
0:02:53 > 0:02:55for you to have a few words with.
0:02:55 > 0:02:57And the goose was very upset,
0:02:57 > 0:02:59flapped its wings and went, phhhhht, like this,
0:02:59 > 0:03:04and Lorenz said, "Oh, dear, oh, dear! All over ze trousers!"
0:03:04 > 0:03:07And, very embarrassed, took his handkerchief
0:03:07 > 0:03:12and then blew his nose which produced a great smear
0:03:12 > 0:03:14of goose droppings all down his cheek.
0:03:14 > 0:03:17And I had to continue asking him serious questions
0:03:17 > 0:03:21about animal behaviour while he was covered in goose droppings.
0:03:21 > 0:03:25But at least he saw the joke, because after it was all over,
0:03:25 > 0:03:28he took his book and he drew a nice little cartoon of the whole event
0:03:28 > 0:03:30in the front for me.
0:03:34 > 0:03:37Today, film-makers use this imprinting
0:03:37 > 0:03:39technique for their own purposes.
0:03:42 > 0:03:46The first living creature these young goslings saw was Rose Buck,
0:03:46 > 0:03:50and they stayed with her. They even shared her bed with her.
0:03:53 > 0:03:55Who am I?
0:03:58 > 0:04:00Off you go, then.
0:04:00 > 0:04:02Good boys! Come on, then!
0:04:02 > 0:04:06So now they too follow her everywhere.
0:04:06 > 0:04:07On foot...
0:04:08 > 0:04:12..and, eventually, even in flight.
0:04:35 > 0:04:37These are greylag geese,
0:04:37 > 0:04:42the same species that Konrad Lorenz worked with.
0:04:42 > 0:04:44And they are following me because, like his geese,
0:04:44 > 0:04:47they've been imprinted on a human being.
0:04:50 > 0:04:53And that human being, of course, is Rose.
0:05:15 > 0:05:16HE LAUGHS
0:05:23 > 0:05:27You see, they're all flying straight in line behind one another,
0:05:27 > 0:05:31just as they do in the wild.
0:05:31 > 0:05:32That's because there's a little turbulence
0:05:32 > 0:05:35from the end of the wing there,
0:05:35 > 0:05:39which makes it easier for that one to get lift,
0:05:39 > 0:05:42so they save energy by flying in this way.
0:05:42 > 0:05:46But who could have dreamt that it would have been possible
0:05:46 > 0:05:51to be sitting alongside one as they do that?
0:05:51 > 0:05:52Look at them.
0:05:52 > 0:05:53Isn't it wonderful?
0:06:13 > 0:06:16The discovery of imprinting, of course,
0:06:16 > 0:06:19was more than just a boon to film-makers.
0:06:19 > 0:06:23It threw a new light not only on the behaviour of many birds,
0:06:23 > 0:06:25but of animals of all kinds,
0:06:25 > 0:06:28including mammals and, indeed, ourselves.
0:06:30 > 0:06:32But back in the '50s,
0:06:32 > 0:06:36other scientists were tackling some even more mind-boggling problems.
0:06:39 > 0:06:44For example, we knew next to nothing about that great mystery of all,
0:06:44 > 0:06:46the origin of life.
0:06:46 > 0:06:51And then in 1952, the year I happened to join television,
0:06:51 > 0:06:54a young postgraduate student at the University of Chicago,
0:06:54 > 0:06:56Stanley Miller, decided to try
0:06:56 > 0:07:01and recreate the conditions of the early Earth in the laboratory.
0:07:05 > 0:07:09It was a remarkably ambitious project for a 22-year-old student.
0:07:17 > 0:07:20He used apparatus like this.
0:07:20 > 0:07:23In the bottom flask is boiling water.
0:07:23 > 0:07:27Steam from it rises up here through these tubings
0:07:27 > 0:07:30and goes to this flask here,
0:07:30 > 0:07:32which he'd filled with a mixture of gases,
0:07:32 > 0:07:34methane, ammonia and hydrogen,
0:07:34 > 0:07:38which are thought to have been present in the early atmosphere.
0:07:38 > 0:07:42And through that, he passed an electric discharge
0:07:42 > 0:07:47from these two electrodes, mimicking lightning.
0:07:47 > 0:07:51Stanley Miller was working against a deadline.
0:07:51 > 0:07:54His professor had given him six months.
0:07:54 > 0:07:56If by the end of that time he had gone no results,
0:07:56 > 0:07:59he had to abandon these experiments
0:07:59 > 0:08:03and return to working on his PhD, which was about meteorites.
0:08:19 > 0:08:21But his intuition proved correct.
0:08:36 > 0:08:40A week later, he found a brown liquid in the bottom of the flask.
0:08:40 > 0:08:44It contained amino acids, the building blocks of life.
0:08:44 > 0:08:49Stanley Miller had demonstrated that the first steps on the path
0:08:49 > 0:08:52leading to life could have happened spontaneously.
0:09:03 > 0:09:05Conditions very similar to those
0:09:05 > 0:09:10created by Miller in his laboratory do actually
0:09:10 > 0:09:14exist in the natural world today, in volcanic hot springs.
0:09:15 > 0:09:20So when, in 1979, we came to make a series called Life on Earth,
0:09:20 > 0:09:24it seemed a good idea to start our story beside
0:09:24 > 0:09:27just such a hot spring in Yellowstone National Park, Wyoming.
0:09:29 > 0:09:33And in these springs, staining them a whole variety of colours,
0:09:33 > 0:09:36there flourish micro-organisms.
0:09:36 > 0:09:39Micro-organisms that look to be almost identical
0:09:39 > 0:09:42with some of the earliest fossils that we know.
0:09:45 > 0:09:47But even as we were filming Life on Earth,
0:09:47 > 0:09:50there was a momentous discovery,
0:09:50 > 0:09:54one that suggested a different location for the origin of life.
0:09:58 > 0:10:01In 1979, the deep-water submersible Alvin,
0:10:01 > 0:10:05working near the Galapagos Islands, descended more than 2,000 metres
0:10:05 > 0:10:08to the floor of the Pacific Ocean.
0:10:10 > 0:10:13Its mission was to film volcanic activity.
0:10:16 > 0:10:18But instead of a barren volcanic landscape,
0:10:18 > 0:10:22its searchlights revealed a whole community of hitherto-unknown
0:10:22 > 0:10:25animals that were living in this blackness.
0:10:26 > 0:10:31There were giant tube worms nearly a metre long, and among them,
0:10:31 > 0:10:32small fish and crabs.
0:10:35 > 0:10:38But what were all these creatures feeding on,
0:10:38 > 0:10:40so far from the energy of the sun?
0:10:43 > 0:10:46Plumes of water superheated by the molten rock
0:10:46 > 0:10:50deep in the Earth's crust were spouting into the cold sea,
0:10:50 > 0:10:53and the chemical compounds they carried
0:10:53 > 0:10:56were being deposited as great, rocky towers.
0:11:01 > 0:11:05Some of the dissolved chemicals were serving as food for bacteria.
0:11:07 > 0:11:10The bacteria nourished the tube worm and they, in turn,
0:11:10 > 0:11:13were food for crabs and fish.
0:11:17 > 0:11:19More of these astonishing ecosystems
0:11:19 > 0:11:22have now been discovered elsewhere in the world's oceans,
0:11:22 > 0:11:26each with its own unique inhabitants.
0:11:32 > 0:11:37Clearly events such as these could have supported
0:11:37 > 0:11:42the first micro-organisms that appeared in the primeval seas
0:11:42 > 0:11:43nearly 4,000 million years ago.
0:11:47 > 0:11:50But, if so, how did those early forms of life give rise
0:11:50 > 0:11:53to the great diversity of creatures that live today?
0:11:55 > 0:11:59That problem has puzzled thinkers since the very beginning of science.
0:12:05 > 0:12:08In the 19th century, zoology was still at stage
0:12:08 > 0:12:12of collecting and identifying species.
0:12:12 > 0:12:15People went out to the wilder parts of the world
0:12:15 > 0:12:17and shot an animal, often the bigger, the better,
0:12:17 > 0:12:22and then brought them back in order to be measured and identified.
0:12:22 > 0:12:26And here in the storerooms of London's Natural History Museum,
0:12:26 > 0:12:29you can see some of the fruits of their endeavours.
0:12:30 > 0:12:35These specimens, carefully arranged in groups of similar species,
0:12:35 > 0:12:38together form a catalogue of life on the planet.
0:12:41 > 0:12:45It was Charles Darwin who made sense of this vast catalogue
0:12:45 > 0:12:48with his theory of evolution by natural selection.
0:12:48 > 0:12:51And in 1979,
0:12:51 > 0:12:55we used that theory as the basis of that television series
0:12:55 > 0:12:59surveying the whole of the natural world which we called Life on Earth.
0:13:06 > 0:13:08There are some four million
0:13:08 > 0:13:10different kinds of animals and plants in the world.
0:13:10 > 0:13:15Four million different solutions to the problems of staying alive.
0:13:15 > 0:13:19This is the story of how a few of them came to be as they are.
0:13:27 > 0:13:28Early on in the series,
0:13:28 > 0:13:32I went to the Galapagos to have a look at the animals that had
0:13:32 > 0:13:36provided Darwin with evidence for his theory, the giant tortoises.
0:13:41 > 0:13:42This one, for example,
0:13:42 > 0:13:46with its deep rounded shell, comes from a well-watered island
0:13:46 > 0:13:49where it can feed mainly on vegetation on the ground.
0:13:51 > 0:13:55This one, on the other hand, has a peak to the front of its shell
0:13:55 > 0:13:59that enables it to stretch its long neck upwards.
0:13:59 > 0:14:02It comes from an arid island where the tortoises often have to crane up
0:14:02 > 0:14:07to reach the only food available, the branches of trees and cactus.
0:14:07 > 0:14:11The suspicion grew in Darwin's mind that species were not fixed forever.
0:14:11 > 0:14:15Perhaps these tortoises were all descended from common ancestors
0:14:15 > 0:14:19and had changed to suit their particular islands.
0:14:23 > 0:14:26The differences that Darwin had noticed amongst these
0:14:26 > 0:14:29Galapagos animals were, of course, more tiny.
0:14:29 > 0:14:32But if they could develop, wasn't it possible that,
0:14:32 > 0:14:35over the thousands or millions of years,
0:14:35 > 0:14:37a whole series of such differences
0:14:37 > 0:14:40might add up to one revolutionary change?
0:14:41 > 0:14:46He gave the idea irresistible force by suggesting a mechanism
0:14:46 > 0:14:48which might have bought that about.
0:14:48 > 0:14:50He called the mechanism natural selection.
0:14:53 > 0:14:57So, Darwin had explained how different species evolved.
0:14:58 > 0:15:01But he also proposed that all life was inter-related,
0:15:01 > 0:15:03having come from a common origin.
0:15:05 > 0:15:08That, of course, implied the existence of intermediate forms,
0:15:08 > 0:15:10links between the great animal groups.
0:15:12 > 0:15:17One leading candidate connecting fish to amphibians had already
0:15:17 > 0:15:21been discovered in the rivers of northern Australia, the lungfish.
0:15:22 > 0:15:25Although it lives in water, just like an ordinary fish,
0:15:25 > 0:15:28it can also breathe air through a pouch in its throat,
0:15:28 > 0:15:29like a simple lung.
0:15:31 > 0:15:35And it punts itself along the river bottom using two pairs
0:15:35 > 0:15:40of muscular fins, placed low on its body, just like simple legs.
0:15:40 > 0:15:44But the actual ancient creature that linked fish
0:15:44 > 0:15:48and the first land-living creatures wasn't found until very recently.
0:15:49 > 0:15:53Fossils of fish very like these Australian lungfish
0:15:53 > 0:15:59are known from rocks that are some 400 million years old.
0:15:59 > 0:16:03And we can be pretty sure that those ancient fish could breathe air.
0:16:04 > 0:16:08But could they manage to get out of the water and up onto the land?
0:16:09 > 0:16:13How could they have managed that? Nobody could be sure.
0:16:13 > 0:16:15There was a missing link.
0:16:16 > 0:16:20And then, this turned up in 2004.
0:16:23 > 0:16:27This was found in Arctic Canada
0:16:27 > 0:16:30and was called tiktaalik.
0:16:31 > 0:16:34You see, it's about the same size as a lungfish but it's got
0:16:34 > 0:16:40a skull which is flattened that way, and a row of formidable teeth.
0:16:40 > 0:16:42But what about its limbs?
0:16:42 > 0:16:45Well, a number of specimens of its limbs have been found,
0:16:45 > 0:16:47and here's one of them.
0:16:47 > 0:16:51It had a fleshy base, just like a lungfish,
0:16:51 > 0:16:56but it also had a joint in the middle of that limb.
0:16:56 > 0:17:01An elbow. And at the end, a range of digits.
0:17:01 > 0:17:04This, almost certainly, was the first limb
0:17:04 > 0:17:08to move a creature up onto land.
0:17:11 > 0:17:15So, tiktaalik probably looked a bit like present-day amphibians,
0:17:15 > 0:17:16such as salamanders.
0:17:16 > 0:17:19The link between fish and land-living animals
0:17:19 > 0:17:22had now been found.
0:17:22 > 0:17:25Another piece in the jigsaw of life had been put in place.
0:17:28 > 0:17:32But, 60 years ago, there was another baffling puzzle.
0:17:32 > 0:17:35The odd way in which animals are distributed on our planet.
0:17:38 > 0:17:42For example, why is it that closely related groups of animals
0:17:42 > 0:17:45can occur on both sides of an ocean,
0:17:45 > 0:17:49in West Africa and South America, for example?
0:17:49 > 0:17:51Well, birds could fly across the ocean, yes.
0:17:51 > 0:17:54Mammals and reptiles, well, conceivably they might have
0:17:54 > 0:17:59floated across on rafts of vegetation, but what about frogs?
0:17:59 > 0:18:02Frogs like this one.
0:18:02 > 0:18:05Frogs have permeable skins, and they're poisoned by salt water,
0:18:05 > 0:18:09so they couldn't have floated across.
0:18:09 > 0:18:15But maybe it wasn't the frogs that moved, maybe it was the continents.
0:18:20 > 0:18:23That was the suggestion that was being debated
0:18:23 > 0:18:26when I was a geology student at Cambridge in 1945.
0:18:28 > 0:18:32Could it be that the continents of the Earth were fragments of a much
0:18:32 > 0:18:36larger super-continent that, over millions of years, had drifted apart?
0:18:39 > 0:18:44So, I asked the Professor of Geology here at Cambridge University
0:18:44 > 0:18:48why he didn't tell us students about that possibility.
0:18:48 > 0:18:51And he replied, rather loftily,
0:18:51 > 0:18:54"When you can demonstrate that there is a force
0:18:54 > 0:18:59"that will move a continent by a millimetre, I will consider it.
0:18:59 > 0:19:03"But until then, the idea is moonshine, dear boy."
0:19:05 > 0:19:10But, by the time I came to make The Living Planet in 1984,
0:19:10 > 0:19:12the answer had become clear.
0:19:12 > 0:19:13And I thought
0:19:13 > 0:19:15that one of the most dramatic ways to reveal it
0:19:15 > 0:19:18would be to stand high up in the greatest mountain
0:19:18 > 0:19:20range on earth, the Himalayas.
0:19:22 > 0:19:28They were raised to their present height about 65 million years ago
0:19:28 > 0:19:30from the bottom of the sea.
0:19:30 > 0:19:34And what is the evidence for that extraordinary statement?
0:19:34 > 0:19:38Well, it can be found all over the place, just up here.
0:19:43 > 0:19:47These slopes are littered...
0:19:48 > 0:19:50..with fragments...
0:19:52 > 0:19:53..like these.
0:19:54 > 0:19:59This is obviously a shell that has been turned to stone, a fossil.
0:19:59 > 0:20:03But I'm about as far as possible as it is to be from the sea.
0:20:03 > 0:20:05Not only am I in the middle of Asia,
0:20:05 > 0:20:07hundreds of miles from the sea,
0:20:07 > 0:20:11but I'm over two vertical miles above its level.
0:20:11 > 0:20:16What forces could possibly have raised the seabed to these heights?
0:20:16 > 0:20:19Well, we now know that those forces are still in action.
0:20:25 > 0:20:30These Icelandic volcanoes erupt from huge cracks, or fissures,
0:20:30 > 0:20:33which regularly open up in the line which runs
0:20:33 > 0:20:36right across the width of the island.
0:20:36 > 0:20:39And that line itself is only the northern end
0:20:39 > 0:20:44of a huge line of weakness that runs for thousands of miles
0:20:44 > 0:20:47southwards from Iceland, right round the side of the globe.
0:20:50 > 0:20:54And the sheer weight of these molten ingots of rock prevents them
0:20:54 > 0:20:57from being swept away from the vent by the gale,
0:20:57 > 0:21:01so there's little danger of them suddenly coming our way.
0:21:01 > 0:21:05Well, there were pieces of lava the size of a suitcase landing
0:21:05 > 0:21:08with a thud into the ash plain as we stood.
0:21:08 > 0:21:12And you could see them glowing red hot and thumping down
0:21:12 > 0:21:17into the ash, and the question is just how close could you get.
0:21:17 > 0:21:20Well, we got quite close enough, and when a lump of lava
0:21:20 > 0:21:24did actually land only about three or four feet behind me,
0:21:24 > 0:21:26I thought the time had come to leave.
0:21:29 > 0:21:32Now we know that it was eruptions like these,
0:21:32 > 0:21:36but at the bottom of the sea, that explain the mystery.
0:21:38 > 0:21:41Molten rock rises from the Earth's core.
0:21:44 > 0:21:48Near the surface, the rock spreads in two directions and go sideways.
0:21:49 > 0:21:50It begins to lose heat.
0:21:52 > 0:21:57Eventually the much-cooler rock sinks back down.
0:21:58 > 0:22:00Through this spreading process,
0:22:00 > 0:22:03the Earth's crust is very slowly dragged apart.
0:22:05 > 0:22:09And it is this that ultimately makes the continents move.
0:22:12 > 0:22:16So, what in my youth was no more than a speculative theory
0:22:16 > 0:22:18is now fully accepted.
0:22:18 > 0:22:20Continents do drift.
0:22:22 > 0:22:25The Indian sub-continent has moved north,
0:22:25 > 0:22:29pushing up the sediments that had accumulated on the sea floor
0:22:29 > 0:22:31ahead of it to form the Himalayas.
0:22:32 > 0:22:36Which is how my fossilised sea shell came to rest in mountains
0:22:36 > 0:22:38over two miles high.
0:22:41 > 0:22:45So, continental drift explains why animals
0:22:45 > 0:22:48are distributed in the way they are around the world.
0:22:48 > 0:22:52But why do they behave in the way they do?
0:22:52 > 0:22:56Well, that has also been the subject of investigation
0:22:56 > 0:22:57in the last few decades.
0:22:57 > 0:23:01In particular, how do they communicate with one another?
0:23:01 > 0:23:05Filming that gave me a chance to join in those conversations.
0:23:08 > 0:23:12A double knock on a tree is a statement used by
0:23:12 > 0:23:17a Patagonian woodpecker to say, "This patch of the forest is mine."
0:23:17 > 0:23:19And if someone else claims it,
0:23:19 > 0:23:21he'll certainly knock out a challenge and come to investigate.
0:23:40 > 0:23:43North American male cicadas, singing their deafening song,
0:23:43 > 0:23:46can be summoned by the noise of a female's wing flick
0:23:46 > 0:23:48that sounds like a finger snap.
0:23:55 > 0:23:56Now, can I bring you back?
0:23:57 > 0:24:00And a male wants to investigate that.
0:24:00 > 0:24:03How about coming this way?
0:24:07 > 0:24:12Oh, the noise is awful!
0:24:14 > 0:24:17In Minnesota, it's not difficult to summon a wolf.
0:24:17 > 0:24:21HE HOWLS
0:24:25 > 0:24:26HE HOWLS
0:24:27 > 0:24:30HE IMITATES BIRD
0:24:30 > 0:24:32On Australia's Lord Howe Island,
0:24:32 > 0:24:35there are other conversations to be had.
0:24:35 > 0:24:37HE IMITATES BIRD
0:24:40 > 0:24:43Nobody knows why it happens,
0:24:43 > 0:24:46but when you make strange noises here,
0:24:46 > 0:24:48seabirds fall from the sky.
0:24:49 > 0:24:52HE IMITATES BIRD
0:24:54 > 0:24:57HE IMITATES BIRD
0:25:05 > 0:25:06And in Florida,
0:25:06 > 0:25:11you can get little lizards to reply to a mirror.
0:25:11 > 0:25:14And there, that's it.
0:25:14 > 0:25:17The full works.
0:25:20 > 0:25:23All those signals are fairly simple,
0:25:23 > 0:25:28but by the 1990s, long-term studies were showing that some monkeys
0:25:28 > 0:25:31even have the beginnings of a vocabulary.
0:25:33 > 0:25:37At dawn, vervet monkeys come down from the trees
0:25:37 > 0:25:40to search for food on the ground.
0:25:43 > 0:25:45Down here, of course, they are much more vulnerable
0:25:45 > 0:25:50than they were up in the trees, but there's always a sentinel on watch.
0:25:55 > 0:25:58A python.
0:25:58 > 0:26:01The sentinel gives a call which means "snake".
0:26:01 > 0:26:05MONKEY CHATTERS
0:26:11 > 0:26:14The meaning is very precise and is only made when a snake appears.
0:26:14 > 0:26:18It could be called a word and when other vervets hear it,
0:26:18 > 0:26:20they know exactly what the danger is.
0:26:24 > 0:26:29Calls and such specific meanings are very rare in the animal world,
0:26:29 > 0:26:32but vervets have developed several of them.
0:26:37 > 0:26:40A call that means danger from the air.
0:26:41 > 0:26:43And the vervets run into the denser branches
0:26:43 > 0:26:47where the eagle won't pursue them for fear of damaging its wings.
0:26:53 > 0:26:57From the safety of the thorny branches,
0:26:57 > 0:27:00the vervets scream furiously and one is even brave enough
0:27:00 > 0:27:02to launch a lightening attack.
0:27:10 > 0:27:14Communication between males and females of a species,
0:27:14 > 0:27:17not only by sound, but by visual signals,
0:27:17 > 0:27:20has, of course, long fascinated naturalists,
0:27:20 > 0:27:23particularly in the 19th century.
0:27:24 > 0:27:26When I was a boy of about nine,
0:27:26 > 0:27:31I read a book that thrilled me to the core. This is it.
0:27:31 > 0:27:33It's called The Malay Archipelago,
0:27:33 > 0:27:37The Land of the Orang-utan and The Bird of Paradise,
0:27:37 > 0:27:41by Alfred Russel Wallace.
0:27:41 > 0:27:45It contained one particularly exciting illustration,
0:27:45 > 0:27:49this is it, it shows native tribespeople
0:27:49 > 0:27:53hunting birds of paradise, which are displaying in the tree.
0:27:53 > 0:27:55And I dreamt that sometime
0:27:55 > 0:28:00I might get there to see it for myself.
0:28:00 > 0:28:02Well, in 1957, I did.
0:28:07 > 0:28:09From the capital of New Guinea, Port Moresby,
0:28:09 > 0:28:11we chartered a plane
0:28:11 > 0:28:12and flew inland,
0:28:12 > 0:28:16heading for territory that was still regarded as being pretty wild.
0:28:16 > 0:28:19After an hour's flight, we were nearing the middle
0:28:19 > 0:28:21of the mountains when suddenly,
0:28:21 > 0:28:26we saw a wide, fertile valley, ringed with mountains.
0:28:26 > 0:28:29This was our destination, the place in which we planned to work
0:28:29 > 0:28:33for the next few months, the valley of the Waghi River.
0:28:35 > 0:28:38The Waghi people knew about birds of paradise all right!
0:28:38 > 0:28:40They used their plumes as money
0:28:40 > 0:28:44and they were essential elements in all important transactions.
0:28:48 > 0:28:50I watched a ceremonial dance
0:28:50 > 0:28:52in which each man had decorated himself
0:28:52 > 0:28:57with the plumes of at least 30 birds of paradise.
0:28:57 > 0:29:01Here, I was looking at the remains of 20,000 dead birds.
0:29:01 > 0:29:03They were clearly so keenly hunted,
0:29:03 > 0:29:06we stood little chance of finding them here.
0:29:08 > 0:29:11So, cameraman Charles Lagus and I
0:29:11 > 0:29:14decided to go into wilder country to the north.
0:29:16 > 0:29:18It was hard walking, but when we reached the top of the ridge
0:29:18 > 0:29:22that formed the wall of the valley, we ran into trouble.
0:29:22 > 0:29:27I found, to my horror, that the men were refusing to go any further.
0:29:27 > 0:29:32They told me firmly that this was the end of their tribal frontier.
0:29:32 > 0:29:35I thought we weren't paying them enough so I thought,
0:29:35 > 0:29:38another cake of salt all round, that'll be all right.
0:29:38 > 0:29:43But no, it turned out that they said the people who lived beyond there
0:29:43 > 0:29:48were bad men, they eat people, they said,
0:29:48 > 0:29:49we won't go there.
0:29:49 > 0:29:54And I said, "Come along, lads, we can manage this."
0:29:54 > 0:29:57When suddenly I noticed a white feather
0:29:57 > 0:29:58flickering behind a boulder
0:29:58 > 0:30:00and I looked and there was another one behind a tree
0:30:00 > 0:30:03and while I was wondering what this meant,
0:30:03 > 0:30:05suddenly these men leapt out of hiding
0:30:05 > 0:30:08and came charging down the path towards us,
0:30:08 > 0:30:11waving stone axes and spears
0:30:11 > 0:30:14and I simply couldn't think of what to do
0:30:14 > 0:30:17except to go towards them
0:30:17 > 0:30:20and stick out my hand and said, "Good afternoon".
0:30:21 > 0:30:25And to my astonishment, they seized my hand, pumped it up and down,
0:30:25 > 0:30:27and said, "Good afternoon."
0:30:28 > 0:30:31And it turned out that the reason was that this tribal frontier
0:30:31 > 0:30:36was where, when the two people met, they made sure the other person
0:30:36 > 0:30:40thought they were still warlike and tough, because if they didn't,
0:30:40 > 0:30:42and appeared to be soft and peaceable,
0:30:42 > 0:30:46obviously they were ready for a bit of rape and pillage.
0:30:46 > 0:30:50So whenever the two people met, they always looked ferocious.
0:30:50 > 0:30:51It certainly convinced me.
0:30:54 > 0:30:55Much relieved, we carried on.
0:30:57 > 0:31:00We heard calls of birds of paradise, but we just couldn't find a place
0:31:00 > 0:31:02where we could film them.
0:31:04 > 0:31:09And then, after three weeks, one morning at dawn, our luck changed.
0:31:10 > 0:31:14Low-down, in a tree, a plumed bird of paradise.
0:31:14 > 0:31:16And there, his unplumed female.
0:31:17 > 0:31:20As far as I knew, this was the first film
0:31:20 > 0:31:24ever taken of a bird of paradise displaying in the wild.
0:31:26 > 0:31:28The pictures were OK, as far as they went.
0:31:28 > 0:31:32But Charles's camera was an old clockwork one,
0:31:32 > 0:31:34and it made a noise like a cement mixer,
0:31:34 > 0:31:37so I couldn't record the sound while he was filming.
0:31:37 > 0:31:41But when he had finished, I turned on the recorder
0:31:41 > 0:31:43and I got two sets of calls,
0:31:43 > 0:31:45one which went "wah-wah" with two,
0:31:45 > 0:31:48and one, "wah-wah-wah", with three.
0:31:48 > 0:31:51And when we came back I joined the two together so they ran
0:31:51 > 0:31:54and we could play it throughout the display.
0:32:00 > 0:32:03And after the show had gone out, I got a letter from my old
0:32:03 > 0:32:06professor of zoology, and he said, "Many congratulations on this
0:32:06 > 0:32:10wonderful documentation of bird of paradise displays.
0:32:10 > 0:32:16But had I noticed that, in fact, this bird did its two-note call
0:32:16 > 0:32:19and then its three-note call, alternating, never two together,
0:32:19 > 0:32:21then three together.
0:32:21 > 0:32:24Would I perhaps write a learned paper
0:32:24 > 0:32:26about this strange phenomenon?"
0:32:26 > 0:32:29I had to explain to him that, actually,
0:32:29 > 0:32:33it was a limitation of early natural history photography.
0:32:33 > 0:32:38But the pictures produced by our primitive equipment
0:32:38 > 0:32:42were black-and-white and fuzzy, so 40 years later, I made another
0:32:42 > 0:32:45attempt to film the birds that Wallace had described so vividly.
0:32:45 > 0:32:47As far as I know,
0:32:47 > 0:32:51Wallace wasn't able to climb the tree to get a closer view
0:32:51 > 0:32:55of the birds, but these days we have ways of doing so relatively simply.
0:32:57 > 0:33:01You fire a thin line with a catapult over one of those higher
0:33:01 > 0:33:05branches, haul up a thicker rope, attach a system of counterweights,
0:33:05 > 0:33:08and all you have to do is clip yourself on and off you go.
0:33:22 > 0:33:24And here's the top.
0:33:28 > 0:33:32The birds are in another emergent tree, just like this one,
0:33:32 > 0:33:36and I've got an absolutely clear view of them.
0:33:39 > 0:33:42This, at last, is Wallace's picture come to life.
0:33:42 > 0:33:46He was the first European to glimpse this extraordinary spectacle,
0:33:46 > 0:33:49and he knew well, in general terms, what was happening.
0:33:49 > 0:33:52This is a female, and she has come to pick
0:33:52 > 0:33:56a mate from among the gorgeous males who are displaying.
0:34:01 > 0:34:04The female has hopped on to the perch of the male of her choice,
0:34:04 > 0:34:07that's a straight invitation to mate.
0:34:11 > 0:34:12This is all he does as a father.
0:34:14 > 0:34:18Now she'll fly away and raise her young unaided.
0:34:20 > 0:34:22The females are comparatively drab.
0:34:22 > 0:34:25It's only the male that have extravagant plumes.
0:34:27 > 0:34:31Each of the 40-odd species has its own kind.
0:34:31 > 0:34:33Growing them and displaying them
0:34:33 > 0:34:36must take a huge amount of a male's energy.
0:34:41 > 0:34:45Can it really be worth all this just to mate with a female?
0:34:50 > 0:34:53Well, it seems that it is.
0:34:53 > 0:34:57At least for the male who puts on the most impressive performance,
0:34:57 > 0:35:00for he will mate with virtually all the females in the area.
0:35:08 > 0:35:11So, generation after generation, it is
0:35:11 > 0:35:14only the winner whose genes are passed on,
0:35:14 > 0:35:17and it is this, over many generations,
0:35:17 > 0:35:20that produces such great extravagance of plumage and display.
0:35:23 > 0:35:26It's a process known as sexual selection.
0:35:33 > 0:35:35The males of another family of New Guinea birds
0:35:35 > 0:35:38impress their females not with feathers, but with brightly
0:35:38 > 0:35:42coloured objects, which they collect and display in bowers.
0:35:44 > 0:35:50And this is the work of the master builder among bowerbirds.
0:35:50 > 0:35:54I'm in the Vogelkop on the far western tip of New Guinea,
0:35:54 > 0:35:57and this is the bower of the Vogelkop bowerbird.
0:35:59 > 0:36:02And what an astonishment it is,
0:36:02 > 0:36:04surely one of the wonders of the natural world.
0:36:04 > 0:36:08The bower has been completely roofed over.
0:36:08 > 0:36:12Their orange fruit, these glowing orange dead leaves,
0:36:12 > 0:36:16behind me, there are black fruits,
0:36:16 > 0:36:18all of which has been bought specially by the bird.
0:36:36 > 0:36:41A further step in our understanding of such spectacular behaviour
0:36:41 > 0:36:46came in 1976 when Richard Dawkins published this book,
0:36:46 > 0:36:48The Selfish Gene.
0:36:48 > 0:36:54In it he brings together evolution, genetics and animal behaviour,
0:36:54 > 0:36:59and argues that it is that the gene that drives evolution.
0:37:00 > 0:37:05The survival of an individual animal is of less importance
0:37:05 > 0:37:06than the survival of its genes.
0:37:08 > 0:37:11And thinking about selection at the level of the gene
0:37:11 > 0:37:15also enables us to understand why it is that some animals,
0:37:15 > 0:37:19sometimes, behave in an unselfish way.
0:37:24 > 0:37:28These ants are all female. And they are prepared... Ow!
0:37:28 > 0:37:34They're prepared to attack me in defence of their colony
0:37:34 > 0:37:38and to die in the process, because the genes that they carry are
0:37:38 > 0:37:43the same as their sister workers and indeed, their mothers.
0:37:43 > 0:37:48So in attacking me, they are, in fact, doing their best to help
0:37:48 > 0:37:51ensure that their genes are passed to the next generation.
0:37:51 > 0:37:55You don't have to breed yourself to pass on your own genes.
0:37:55 > 0:38:00All the female worker and soldier ants in this nest are sisters,
0:38:00 > 0:38:03and they share 75% of their genes.
0:38:03 > 0:38:08So the colony acts as a kind of single super-organism,
0:38:08 > 0:38:11and, amazingly, it was discovered that some mammals
0:38:11 > 0:38:13live in a similar kind of community.
0:38:17 > 0:38:20Meerkats in the Kalahari Desert.
0:38:22 > 0:38:25They spend the night in burrows,
0:38:25 > 0:38:29they find all the food they need on the ground.
0:38:29 > 0:38:32They are swift and expert runners.
0:38:32 > 0:38:35But, oddly enough, they also climb,
0:38:35 > 0:38:39and they have very good reasons for doing so.
0:38:39 > 0:38:44But, first of all, they have to warm up in the early morning sun.
0:38:51 > 0:38:55They live in groups in which the only dominant pair breeds,
0:38:55 > 0:38:58and some of their offspring, even when adult, do not breed
0:38:58 > 0:39:01but stay around to help rear the young.
0:39:05 > 0:39:08While one helper watches out for danger, another catches a scorpion
0:39:08 > 0:39:11and encourages one of the youngsters to eat it.
0:39:18 > 0:39:21These helpers appear to be very unselfish,
0:39:21 > 0:39:25but they're acting this way, probably because they share the same genes
0:39:25 > 0:39:28as their charges and by helping them,
0:39:28 > 0:39:33they're ensuring the transmission of those genes to the next generation.
0:39:35 > 0:39:38The first meerkat film we made turned these animals
0:39:38 > 0:39:43into stars, not, I must admit, because of their selfish genes,
0:39:43 > 0:39:46but because of their enchanting personalities.
0:40:04 > 0:40:07The factors that make these animals behave in the way they do
0:40:07 > 0:40:11are transmitted in their genes.
0:40:11 > 0:40:14But what kind of physical structure
0:40:14 > 0:40:17could carry all this information?
0:40:17 > 0:40:19That was one of the great puzzles
0:40:19 > 0:40:22that had intrigued geneticists ever since
0:40:22 > 0:40:26the beginnings of their science a century ago.
0:40:26 > 0:40:30But that mystery too was about to be solved.
0:40:30 > 0:40:33In 1953, here in the Cavendish Laboratories,
0:40:33 > 0:40:38two young researchers, Francis Crick and James Watson,
0:40:38 > 0:40:41were building models like this.
0:40:41 > 0:40:46It was their way of thinking about and investigating the structure
0:40:46 > 0:40:51of a complex molecule that's found in the genes of all animals,
0:40:51 > 0:40:53DNA.
0:40:53 > 0:40:56The crucial bit are these chains
0:40:56 > 0:41:00which encircle the rod, one...
0:41:00 > 0:41:06and here is the second and entwine.
0:41:06 > 0:41:09This is the double helix.
0:41:09 > 0:41:13An extraordinary feat of intellectual deduction.
0:41:13 > 0:41:16And it led to a whole new branch of science,
0:41:16 > 0:41:18molecular genetics.
0:41:18 > 0:41:22More recently, DNA has given us new insights
0:41:22 > 0:41:25into the family relationship of animals
0:41:25 > 0:41:29using a technique called DNA finger-printing.
0:41:29 > 0:41:32It was developed by Sir Alec Jeffreys
0:41:32 > 0:41:34of Leicester University in 1984.
0:41:34 > 0:41:38And using just a simple smear of blood, it's possible not only
0:41:38 > 0:41:41to identify one particular individual,
0:41:41 > 0:41:45but to establish whether or not it's closely related to another.
0:41:46 > 0:41:48For example, we used to think
0:41:48 > 0:41:51that most birds lived in straightforward pairs.
0:41:51 > 0:41:53We watched them courting and mating
0:41:53 > 0:41:56and rearing their young and so we assumed
0:41:56 > 0:41:59that they were faithful to one another.
0:41:59 > 0:42:03But DNA fingerprinting showed us how wrong we were,
0:42:03 > 0:42:06as I explained in The Life of Birds.
0:42:06 > 0:42:08Perhaps the most
0:42:08 > 0:42:10bizarre behaviour of all
0:42:10 > 0:42:14takes place in the suburban gardens of England.
0:42:14 > 0:42:19And it seems that until very recently, nobody even noticed.
0:42:20 > 0:42:24A young female hedge sparrow, a dunnock, ready to lay.
0:42:25 > 0:42:27This is her mate, Alpha,
0:42:27 > 0:42:30singing lustily, declaring his ownership of the nest
0:42:30 > 0:42:34and the territory around it from which he gathers food.
0:42:36 > 0:42:42The pair often feed together, a devoted couple if ever you saw one.
0:42:45 > 0:42:48He seldom lets her out of his sight,
0:42:48 > 0:42:51but she is not as faithful as she might be...
0:42:53 > 0:42:55There's a third bird around,
0:42:55 > 0:42:59Beta, another younger male.
0:42:59 > 0:43:04He's not popular with Alpha and they're continually squabbling.
0:43:05 > 0:43:10Sometimes the fights can get quite vicious and feathers fly.
0:43:11 > 0:43:15But in spite of that, Beta stays around,
0:43:15 > 0:43:17skulking in the hedge.
0:43:20 > 0:43:24Alpha, it seems, has the female to himself once more.
0:43:25 > 0:43:28But she has got her eye cocked.
0:43:28 > 0:43:33Beta is still in the hedge, calling quietly to her.
0:43:36 > 0:43:38She joins him.
0:43:38 > 0:43:42And now, while Alpha is preoccupied with feeding,
0:43:42 > 0:43:45she and Beta get together.
0:43:45 > 0:43:49Twirling her tail is an invitation and, in a split second, they mate.
0:43:55 > 0:43:57Beta flies away.
0:43:59 > 0:44:01But now, out in the open,
0:44:01 > 0:44:05she is courting Alpha with that same old tail twirling.
0:44:05 > 0:44:07And now, he mates with her.
0:44:14 > 0:44:16She has kept two males happy,
0:44:16 > 0:44:20both of whom will help to feed the young when they hatch.
0:44:23 > 0:44:26DNA fingerprinting has now revealed
0:44:26 > 0:44:30that only about a fifth of the apparently monogamous birds
0:44:30 > 0:44:34are actually genuinely faithful to one another.
0:44:35 > 0:44:38Molecular genetics combined with long-term studies
0:44:38 > 0:44:41of animals in the wild have challenged our preconceptions
0:44:41 > 0:44:45about how animals live their lives.
0:44:46 > 0:44:49And there are also long-term studies that have shed light
0:44:49 > 0:44:52on our own evolution and ancestry,
0:44:52 > 0:44:56in particular, those by Jane Goodall,
0:44:56 > 0:45:01who started her work in 1960 in Tanzania on chimps.
0:45:04 > 0:45:08The 26-year-old Jane Goodall arrived in Africa
0:45:08 > 0:45:10with no scientific training
0:45:10 > 0:45:13and had to patiently follow the chimps for two years
0:45:13 > 0:45:17before they allowed her to get close to them.
0:45:21 > 0:45:22In order to identify them,
0:45:22 > 0:45:25she gave them the sort of names we use for one another,
0:45:25 > 0:45:29which got her into a lot of trouble with more conventional scientists,
0:45:29 > 0:45:33who accused her of crediting her animals with human characteristics,
0:45:33 > 0:45:35for which there was no evidence.
0:45:38 > 0:45:41But she made some revolutionary discoveries,
0:45:41 > 0:45:44including proving that chimps use tools
0:45:44 > 0:45:46and even modify them for particular purposes.
0:45:49 > 0:45:52They fish for termites with twigs,
0:45:52 > 0:45:55which they make more effective by stripping off the leaves.
0:46:01 > 0:46:05Manufacturing tools in such a way had, until then,
0:46:05 > 0:46:08been thought to be something that only human beings could do.
0:46:11 > 0:46:13But in the late 1970s,
0:46:13 > 0:46:17chimps on the other side of the continent, in West Africa,
0:46:17 > 0:46:21were discovered using different tools in a different way.
0:46:22 > 0:46:25Placing the nuts in a hole in the root,
0:46:25 > 0:46:28they crack them open with specially selected hammers.
0:46:32 > 0:46:35Repeated use has deepened the hole
0:46:35 > 0:46:38and produced an anvil, which holds the nut in place.
0:46:42 > 0:46:47Using these tools, experienced chimps can crack two nuts a minute.
0:46:51 > 0:46:56For the hardest nuts, they keep and transport rare stone hammers.
0:46:59 > 0:47:01Cracking is not easy.
0:47:01 > 0:47:04You have to choose both a good anvil...
0:47:06 > 0:47:07..and a good hammer.
0:47:16 > 0:47:20Only West African chimpanzees have developed this nut-cracking ability,
0:47:20 > 0:47:24and it takes more than ten years to learn the technique.
0:47:30 > 0:47:34It's now known that chimps use up to 20 different types of tools.
0:47:37 > 0:47:40Nut-cracking was first discovered by Christophe Boesch,
0:47:40 > 0:47:43who had been studying these chimps since 1976.
0:47:45 > 0:47:49And in 1989, I went out to the Ivory Coast to visit him.
0:47:50 > 0:47:54How did you manage to get these animals so accustomed to you,
0:47:54 > 0:47:57so that we could stand as close to them as this?
0:47:59 > 0:48:01Oh, just patience.
0:48:01 > 0:48:03- It took us five years.- Five years?
0:48:03 > 0:48:07Five years, just following them, being always very quiet,
0:48:07 > 0:48:11never aggressive, always the same colours and clothes
0:48:11 > 0:48:13and patience, patience.
0:48:15 > 0:48:18But Christophe wasn't entirely sure
0:48:18 > 0:48:21that he wanted a 63-year-old with him in the forest.
0:48:21 > 0:48:23- IN FRENCH ACCENT: - "Who is this old man?", he said,
0:48:23 > 0:48:25"Who is this old man who want to come?"
0:48:25 > 0:48:27"Is he fit? Can he run?"
0:48:27 > 0:48:29The answer to those was no, on both,
0:48:29 > 0:48:32but, nonetheless, I managed to get there.
0:48:32 > 0:48:36And his technique was that he would travel with them all day,
0:48:36 > 0:48:39wherever they went, and when they moved, he moved.
0:48:39 > 0:48:42And he didn't leave them until they had made their nests at night.
0:48:43 > 0:48:47And only then would he go back to his camp,
0:48:47 > 0:48:49but then get up at four o'clock the next morning
0:48:49 > 0:48:52in order to run back there and sketch them
0:48:52 > 0:48:53before they went off again.
0:48:53 > 0:48:56And he was... Christophe was quite right...
0:48:56 > 0:49:00I mean, it's hugely demanding. I've never been so tired in all my life.
0:49:02 > 0:49:05But Christophe had also discovered a darker side
0:49:05 > 0:49:07to chimps' personalities.
0:49:08 > 0:49:12You don't normally think of them as hunters.
0:49:12 > 0:49:16More as...gentle vegetarians,
0:49:16 > 0:49:19munching fruit and picking leaves.
0:49:19 > 0:49:23But if you follow them for any length of time in their true home,
0:49:23 > 0:49:26these forests in West Africa,
0:49:26 > 0:49:29you discover that they ARE hunters.
0:49:29 > 0:49:32What's more, they hunt in teams
0:49:32 > 0:49:37and have a more complex strategy than any other hunting animal
0:49:37 > 0:49:39except...
0:49:39 > 0:49:41CHIMP SCREECHES LOUDLY
0:49:41 > 0:49:43..except, of course...
0:49:43 > 0:49:44man.
0:49:48 > 0:49:51The technique they will almost certainly use
0:49:51 > 0:49:56is that one of them will be driving the Colobus ahead of him
0:49:56 > 0:50:00and there will be others that go up on either side, who are blockers,
0:50:00 > 0:50:03who won't make any attempt to catch the monkeys,
0:50:03 > 0:50:06and then there are chasers, who go and grab at the monkey if they can
0:50:06 > 0:50:12and, finally, there's one male who will go up ahead and ambush it.
0:50:12 > 0:50:15So, bringing the whole trap closed.
0:50:17 > 0:50:19The monkeys are now getting alarmed.
0:50:21 > 0:50:24A driver's going up, to prevent the group from settling
0:50:24 > 0:50:29and to drive them towards an area where they're more easily trapped.
0:50:29 > 0:50:31Now, it looks as though they're all in position.
0:50:31 > 0:50:34The drivers have gone up, the blockers have gone up and now,
0:50:34 > 0:50:38the one who's going to make the ambush and close the ring,
0:50:38 > 0:50:39he's gone up too.
0:50:39 > 0:50:43The Colobus will be very lucky if they escape now.
0:50:43 > 0:50:45RUSTLING
0:50:47 > 0:50:49MONKEYS SCREECH
0:50:54 > 0:50:56They've got one!
0:51:02 > 0:51:04And now, the kill is brought down,
0:51:04 > 0:51:08so that the females and others can share it.
0:51:12 > 0:51:15And there's the reward for that long chase.
0:51:16 > 0:51:18The divided body of a Colobus monkey.
0:51:19 > 0:51:21These...
0:51:21 > 0:51:23blood-stained faces...
0:51:23 > 0:51:26may well horrify us.
0:51:26 > 0:51:29But we might also see in them
0:51:29 > 0:51:33the face of our long-distant hunting ancestors.
0:51:34 > 0:51:36And if we are...
0:51:36 > 0:51:38appalled...
0:51:38 > 0:51:41by that mob violence and blood lust,
0:51:41 > 0:51:44we might also see in that too, perhaps,
0:51:44 > 0:51:48the origins of the teamwork...
0:51:48 > 0:51:49that have, in the end,
0:51:49 > 0:51:53brought human beings many of their greatest triumphs.
0:51:59 > 0:52:02But the studies of chimpanzees
0:52:02 > 0:52:06started by Jane Goodall, continued by Christophe Boesch and others
0:52:06 > 0:52:08have shown us something else.
0:52:09 > 0:52:11It's not just that chimpanzees are capable
0:52:11 > 0:52:15of developing their own techniques for hunting or tool-making,
0:52:15 > 0:52:18but that each community of chimps
0:52:18 > 0:52:22is capable of developing its own version.
0:52:22 > 0:52:28In other words, chimpanzees' communities have their own cultures.
0:52:28 > 0:52:32And that was thought to be something that was uniquely human.
0:52:32 > 0:52:36Everyone knew, of course, that chimps are our biological cousins,
0:52:36 > 0:52:40but it's only in the last 20 years that we've discovered
0:52:40 > 0:52:45that we share of about 95% of our DNA with them.
0:52:45 > 0:52:48And that's because we now have the tools to find out
0:52:48 > 0:52:50exactly how closely we are all related.
0:52:55 > 0:52:59In 1990, scientists in 20 labs around the world
0:52:59 > 0:53:05set out to identify all the 3,000 million separate chemical units
0:53:05 > 0:53:07that make up the human genetic code.
0:53:12 > 0:53:14It took nearly 13 years, and then,
0:53:14 > 0:53:17exactly 50 years after Crick and Watson had worked out
0:53:17 > 0:53:19the structure of DNA,
0:53:19 > 0:53:22the human genome was cracked.
0:53:22 > 0:53:24And this is it.
0:53:32 > 0:53:36In these volumes is all the information needed
0:53:36 > 0:53:39to define the genetic structure of the human species.
0:53:41 > 0:53:45Each number refers to one of our 23 chromosomes.
0:53:56 > 0:53:58If I open it up,
0:53:58 > 0:54:01you can see that the text consists of
0:54:01 > 0:54:07just one very, very, very long list of just four letters...
0:54:07 > 0:54:09A, C, T, G.
0:54:09 > 0:54:12Each combination represents instructions
0:54:12 > 0:54:16for one element in the human design.
0:54:16 > 0:54:20This is the secret language of DNA.
0:54:20 > 0:54:22This is the book of life.
0:54:24 > 0:54:28And each one of us has our own edition.
0:54:47 > 0:54:49When I first heard, back in 1953,
0:54:49 > 0:54:52that the structure of DNA had been worked out,
0:54:52 > 0:54:56I could scarcely have imagined that it would ever be possible
0:54:56 > 0:54:59to print out the whole of one genome in a book.
0:54:59 > 0:55:02But, today, the process has been so speeded up,
0:55:02 > 0:55:06that it's possible for anyone to have it done in half a day.
0:55:07 > 0:55:12And the comparison between the genome of one species and another
0:55:12 > 0:55:14has proved very revealing.
0:55:16 > 0:55:18The hot chemical springs of Yellowstone
0:55:18 > 0:55:23contain the very simplest form of life, single-celled bacteria,
0:55:23 > 0:55:26about as far removed from our complex selves
0:55:26 > 0:55:28as any organism could be.
0:55:30 > 0:55:36But we share some 200 of our genes with those very early life forms.
0:55:36 > 0:55:38Indeed, there are some genes
0:55:38 > 0:55:42that are common to every single species of life on the planet.
0:55:42 > 0:55:47Our DNA extends in an unbroken chain
0:55:47 > 0:55:51right to the beginning of life, 4,000 million years ago.
0:55:51 > 0:55:55So, now, we can trace our evolutionary heritage
0:55:55 > 0:55:58back through geological time.
0:56:00 > 0:56:03Back to the age of dinosaurs...
0:56:05 > 0:56:08..and further still to the early amphibians.
0:56:10 > 0:56:13Back to the fish...
0:56:17 > 0:56:21..and the first back-boned animals.
0:56:24 > 0:56:27And further still, to the single-celled organisms
0:56:27 > 0:56:32that were the very earliest form of life to appear on this planet.
0:56:39 > 0:56:43So, in my lifetime, science has solved many of the riddles
0:56:43 > 0:56:47which, 60 years ago, seemed so baffling.
0:56:47 > 0:56:50How mountain ranges are formed.
0:56:50 > 0:56:53Why animals are distributed in the way they are,
0:56:53 > 0:56:55and how they communicate with one another.
0:56:55 > 0:56:58How a complex chemical molecule
0:56:58 > 0:57:03can transfer the characteristics of one generation to the next.
0:57:03 > 0:57:07It's even shed some light on that deepest of mysteries,
0:57:07 > 0:57:10the very origin of life.
0:57:10 > 0:57:16So, now, the natural world makes more sense than it ever did,
0:57:16 > 0:57:21which is why studying it is so rewarding and so delightful.