Original subtitles

When I first started making programmes,

the origin of life

and the structure of DNA was unknown

The fact that continents might drift across the surface

of the planet was ridiculed.

Then, science was something you did in museums and laboratories.

Today, that's very different.

Today, scientists travel to the farthest ends of the Earth.

As a result of their discoveries, we can now make sense of what

not so long ago seemed baffling mysteries.

And for the last 60 years, I've been travelling in the footsteps,

trying to translate some of their insights into film.

Early in my television career,

I met the distinguished Austrian scientist Konrad Lorenz,

who was one of the first to try and understand animal behaviour.

He worked with geese,

and he discovered that

if he was the first thing that young goslings saw when they hatched,

they would follow him wherever he went.

It was as if he had become their parent.

He called as this process imprinting and as a result of it,

the young continued to follow him, even as adults.

In 1952, Professor Lorenz published a book explaining how

he could talk to animals and, in particular, to greylag geese.

It was called King Solomon's Ring, and this is it.

And I was given the job of interviewing him

on live television about it.

And I started by saying, now Professor Lorenz, I understand

you can speak greylag goose language,

and I actually have a greylag goose here

for you to have a few words with.

And the goose was very upset,

flapped its wings and went, phhhhht, like this,

and Lorenz said, "Oh, dear, oh, dear! All over ze trousers!"

And, very embarrassed, took his handkerchief

and then blew his nose which produced a great smear

of goose droppings all down his cheek.

And I had to continue asking him serious questions

about animal behaviour while he was covered in goose droppings.

But at least he saw the joke, because after it was all over,

he took his book and he drew a nice little cartoon of the whole event

in the front for me.

Today, film-makers use this imprinting

technique for their own purposes.

The first living creature these young goslings saw was Rose Buck,

and they stayed with her. They even shared her bed with her.

Who am I?

Off you go, then.

Good boys! Come on, then!

So now they too follow her everywhere.

On foot...

..and, eventually, even in flight.

These are greylag geese,

the same species that Konrad Lorenz worked with.

And they are following me because, like his geese,

but they've been imprinted on a human being.

And that human being, of course, is Rose.

HE LAUGHS

You see, they're all flying straight in line behind one another,

just as they do in the wild.

That's because there's a little turbulence

from the end of the wing there,

which makes it easier for that one to get lift,

so they save energy by flying in this way.

But who could have dreamt that it would have been possible

to be sitting alongside one as they do that?

Look at them.

Isn't it wonderful?

The discovery of imprinting, of course,

was more than just a boon to film-makers.

It threw a new light not only on the behaviour of many birds,

but of animals of all kinds,

including mammals and, indeed, ourselves.

But back in the 50s

other scientists were tackling some even more mind-boggling problems.

For example, we knew next to nothing about that great mystery of all,

the origin of life.

And then in 1952, the year I happened to join television,

a young postgraduate student at the University of Chicago,

Stanley Miller, decided to try

and recreate the conditions of the early Earth in the laboratory.

It was a remarkably ambitious project for a 22-year-old student.

He used apparatus like this.

In the bottom flask is boiling water.

Steam from it rises up here through these tubings

and goes to this flask here,

which he'd filled with a mixture of gases,

methane, ammonia and hydrogen,

which are thought to have been present in the early atmosphere.

And through that, he passed an electric discharge

from these two electrodes, mimicking lightning.

Stanley Miller was working against a deadline.

His professor had given him six months.

If by the end of that time he had gone no results,

he had to abandon these experiments

and return to working on his PhD, which was about meteorites.

But his intuition proved correct.

A week later, he found a brown liquid in the bottom of the flask.

It contained amino acids, the building blocks of life.

Stanley Miller had demonstrated that the first steps on the path

leading to life could have happened spontaneously.

Conditions very similar to those

created by Miller in his laboratory do actually

exist in the natural world today, in volcanic hot springs.

So when, in 1979, we came to make a series called Life on Earth,

it seemed a good idea to start our story beside

just such a hot spring in Yellowstone National Park, Wyoming.

And in these springs, staining them a whole variety of colours,

there flourish micro-organisms.

Micro-organisms that look to be almost identical

with some of the earliest fossils that we know.

But even as we were filming Life on Earth,

there was a momentous discovery,

one that suggested a different location for the origin of life.

In 1979, the deep-water submersible Alvin,

working near the Galapagos Islands, descended more than 2,000 metres

to the floor of the Pacific Ocean.

Its mission was to film a volcanic activity.

But instead of a barren volcanic landscape,

its searchlights revealed a whole community of hitherto-unknown

animals that were living in this black this.

There were giant tube worms nearly a metre long, and among them,

small fish and crabs.

But what were all these creatures feeding on,

so far from the energy of the sun?

Plumes of water superheated by the molten rock

deep in the Earth's crust were spouting into the cold sea,

and the chemical compounds they carried

were being deposited as great, rocky towers.

Some of the dissolved chemicals were serving as food for bacteria.

The bacteria nourished the tube worm and they, in turn,

were food for crabs and fish.

More of these astonishing ecosystems

have now been discovered elsewhere in the world's oceans,

each with its own unique inhabitants.

Clearly events such as these could have supported

the first micro-organisms that appeared in the primeval seas

nearly 4,000 million years ago.

But, if so, how did those early forms of life give rise

to the great diversity of creatures that live today?

That problem has puzzled thinkers since the very beginning of science.

In the 19th century, zoology was still at stage

of collecting and identifying species.

People went out to the wilder parts of the world

and shot an animal, often the bigger, the better,

and then brought them back in order to be measured and identified.

And here in the storerooms of London's Natural History Museum,

you can see some of the fruits of their endeavours.

These specimens, carefully arranged in groups of similar species,

together form a catalogue of life on the planet.

It was Charles Darwin who made sense of this vast catalogue

with his theory of evolution by natural selection.

And in 1979,

we used to that theory as the basis of that television series

surveying the whole of the natural world which we called Life on Earth.

There are some four million

different kinds of animals and plants in the world.

Four million different solutions to the problems of staying alive.

This is the story of how a few of them came to be as they are.

Early on in the series,

I went to the Galapagos to have a look at the animals that had

provided Darwin with evidence for his theory, the giant tortoises.

This one, for example,

with its deep rounded shell, comes from a well-watered island

where it can feed mainly on vegetation on the ground.

This one, on the other hand, has a peak to the front of its shell

that enables it to stretch its long neck upwards.

It comes from an arid island where the tortoises often have to crane up

to reach the only food available, the branches of trees and cactus.

The suspicion grew in Darwin's mind that species were not fixed forever.

Perhaps these tortoises were all descended from common ancestors

and had changed to suit their particular islands.

The differences that Darwin had noticed amongst these

Galapagos animals were, of course, more tiny.

But if they could develop, wasn't it possible that,

over the thousands or millions of years,

a whole series of such differences

might add up to one revolutionary change?

He gave the idea irresistible force by suggesting a mechanism

which might have bought that about.

He called the mechanism natural selection.

So, Darwin had explained how different species evolved.

But he also proposed that all life was inter-related,

having come from a common origin.

That, of course, implied the existence of intermediate forms,

links between the great animal groups.

One leading candidate connecting fish to amphibians had already

been discovered in the rivers of northern Australia, the lungfish.

Although it lives in water, just like an ordinary fish,

it can also breathe air through a pouch in its throat,

like a simple lung.

And it punts itself along the river bottom using two pairs

of muscular fins, placed low on its body, just like simple legs.

But the actual ancient creature that linked fish

and the first land-living creatures wasn't found until very recently.

Fossils of fish very like these Australian lungfish

are known from rocks that are some 400 million years old.

And we can be pretty sure that those ancient fish could breathe air.

But could they manage to get out of the water and up onto the land?

How could they have managed that? Nobody could be sure.

There was a missing link.

And then, this turned up in 2004.

This was found in Arctic Canada

and was called tiktaalik.

You see, it's about the same size as a lungfish but it's got

a skull which is flattened that way, and a row of formidable teeth.

But what about its limbs?

Well, a number of specimens of its limbs have been found,

and here's one of them.

It had a fleshy base, just like a lungfish,

but it also had a joint in the middle of that limb.

An elbow. And at the end, a range of digits.

This, almost certainly, was the first limb

to move a creature up onto land.

So, tiktaalik probably looked a bit like present-day amphibians,

such as salamanders.

The link between fish and land-living animals

had now been found.

Another piece in the jigsaw of life had been put in place.

But, 60 years ago, there was another baffling puzzle.

The odd way in which animals are distributed it on our planet.

For example, why is it that closely related groups of animals

can occur on both sides of an ocean,

in West Africa and South America, for example?

Well, birds could fly across the ocean, yes.

Mammals and reptiles, well, conceivably they might have

floated across on rafts of vegetation, but what about frogs?

Frogs like this one.

Frogs have permeable skins, and they're poisoned by salt water,

so they couldn't have floated across.

But maybe it wasn't the frogs that moved, maybe it was the continents.

That was the suggestion that was being debated

when I was a geology student at Cambridge in 1945.

Could it be that the continents of the Earth were fragments of a much

larger super-continent that, over millions of years had drifted apart?

So, I asked the Professor of Geology here at Cambridge University

why he didn't tell us students about that possibility.

And he replied, rather loftily,

"When you can demonstrate that there is a force

that will move a continent by a millimetre, I will consider it.

But until then, the idea is moonshine, dear boy."

But, by the time I came to make The Living Planet in 1984,

the answer had become clear.

And I thought

that one of the most dramatic ways to reveal it

would be to stand high up in the greatest mountain

range on earth, the Himalayas.

They were raised to their present height about 65 million years ago

from the bottom of the sea.

And what is the evidence for that extraordinary statement?

Well, it can be found all over the place, just up here.

These slopes are littered...

..with fragments...

..like these.

This is obviously a shell that has been turned to stone, a fossil.

But I'm about as far as possible as it is to be from the sea.

Not only am I in the middle of Asia,

hundreds of miles from the sea,

but I'm over two vertical miles above its level.

What forces could possibly have raised the seabed to these heights?

Well, we now know that those forces are still in action.

These Icelandic volcanoes erupt from huge cracks, or fissures,

which regularly open up in the line which runs

right across the width of the island.

And that line itself is only the northern end

of a huge line of weakness that runs for thousands of miles

southwards from Iceland, right round the side of the globe.

And the sheer weight of these molten ingots of rock prevents them

from being swept away from the vent by the gale,

so there's little danger of them suddenly coming our way.

Well, there were pieces of lava the size of a suitcase landing

with a thud into the ash plain as we stood.

And you could see them glowing red hot and thumping down

into the ash, and the question is just how close could you get.

Well, we got quite close enough, and when a lump of lava

did actually land only about three or four feet behind me,

I thought the time had come to leave.

Now we know that it was eruptions like these,

but at the bottom of the sea, that explain the mystery.

Molten rock rises from the Earth's core.

Near the surface, the rock spreads in two directions and go sideways.

It begins to lose heat.

Eventually the much-cooler rock sinks back down.

Through this spreading process,

the Earth's crust is very slowly dragged apart.

And it is this that ultimately makes the continents move.

So, what in my youth was no more than a speculative theory

is now fully accepted.

Continents do drift.

The Indian sub-continent has moved north,

pushing up the sediments that had accumulated on the sea floor

ahead of it to form the Himalayas.

Which is how my fossilised sea shell came to rest in mountains

over two miles high.

So, continental drift explains why animals

are distributed in the way they are around the world.

But why do they behave in the way they do?

Well, that has also been the subject of an investigation

in the last few decades.

In particular, how do they communicate with one another?

Filming that gave me a chance to join in those conversations.

A double knock on a tree is a statement used by

a Patagonian woodpecker to say that this patch of the forest is mine.

And if someone else claims it,

he'll certainly knock out a challenge and come to investigate.

North American male cicadas, singing their deafening song,

can be summoned by the noise of a female's wing flick

that sounds like a finger snap.

Now, can I bring you back?

And a male wants to investigate that.

How about coming this way?

Oh, the noise is awful!

In Minnesota, it's not difficult to summon a wolf.

HE HOWLS

HE HOWLS

HE IMITATES BIRD

On Australia's Lord Howe Island,

there are other conversations to be had.

HE IMITATES BIRD

Nobody knows why it happens,

but when you make strange noises here,

seabirds fall from the sky.

HE IMITATES BIRD

HE IMITATES BIRD

And in Florida,

you can get little lizards to reply to a mirror.

And there, that's it.

The full works.

All those signals are fairly simple,

but by the 1990s, long-term studies were showing that some monkeys

even have the beginnings of a vocabulary.

At dawn, vervet monkeys come down from the trees

to search for food on the ground.

Down here, of course, they are much more vulnerable

than they were up in the trees, but there's always a sentinel on watch.

A python.

The sentinel gives a call which means snake.

MONKEY CHATTERS

The meaning is very precise and is only made when a snake appears.

It could be called a word and when other vervets hear it,

they know exactly what the danger is.

Calls and such specific meanings are very rare in the animal world,

but vervets have developed several of them.

A call that means danger from the air.

And the vervets run into the denser branches

where the eagle won't pursue them for fear of damaging its wings.

From the safety of the thorny branches,

the vervets scream furiously and one is even brave enough

to launch a lightening attack.

Communication between males and females of a species,

not only by sound, but by visual signals,

has, of course, long fascinated naturalists,

particularly in the 19th century.

When I was a boy of about nine,

I read a book that thrilled me to the core. This is it.

It's called the Malay Archipelago,

The Land of the Orang-utan and The Bird of Paradise,

by Alfred Russel Wallace.

It contained one particularly exciting illustration,

this is it, it shows native tribes' people

hunting birds of paradise, which are displaying in the tree.

And I dreamt that sometime

I might get there to see it for myself.

Well, in 1957, I did.

From the capital of New Guinea, Port Moresby,

we chartered a plane

and flew inland,

heading for territory that was still regarded as being pretty wild.

After an hour's flight, we were nearing the middle

of the mountains when suddenly,

we saw a wide, fertile valley, ringed with mountains.

This was our destination, the place in which we planned to work

for the next few months, the valley of the Waghi River.

The Waghi people knew about birds of paradise all right!

They used their plumes as money

and they were essential elements in all important transactions.

I watched a ceremonial dance

in which each man had decorated himself

with the plumes of at least 30 birds of paradise.

Here, I was looking at the remains of 20,000 dead birds.

They were clearly so keenly hunted,

we stood little chance of finding them here.

So, cameraman Charles Lagus and I

decided to go into wilder country to the north.

It was hard walking, but when we reached the top of the ridge

that formed the wall of the valley, we ran into trouble.

I found, to my horror, that the men were refusing to go any further.

They told me firmly that this was the end of their tribal frontier.

I thought we weren't paying them enough so I thought,

another cake of salt all round, that'll be all right.

But no, it turned out that they said the people who lived beyond there

were bad men, they eat people, they said,

we won't go there.

And I said, "Come along, lads, we can manage this."

When suddenly I noticed a white feather

flickering behind a boulder

and I looked and there was another one behind a tree

and while I was wondering what this meant,

suddenly these men leapt out of hiding

and came charging down the path towards us,

waving stone axes and spears

and I simply couldn't think of what to do

except to go towards them

and stick out my hand and said, "Good afternoon".

And to my astonishment, they seized my hand, pumped it up and down,

and said, "Good afternoon."

And it turned out that the reason was that this tribal frontier

was where, when the two people met, they made sure the other person

thought they were still warlike and tough, because if they didn't,

and appeared to be soft and peaceable,

obviously they were ready for a bit of rape and pillage.

So whenever to people met, they always looked ferocious.

It certainly convinced me.

Much relieved, we carried on.

We heard calls of birds of paradise, but we just couldn't find a place

where we could film them.

And then, after three weeks, one morning at dawn, our luck changed.

Low-down, in a tree, a plumed bird of paradise.

And there, his unplumed female.

As far as I knew, this was the first film

ever taken of a bird of paradise displaying in the wild.

The pictures were OK, as far as they went.

But Charles's camera was an old clockwork one,

and it made a noise like a cement mixer,

so I couldn't record the sound while he was filming.

But when he had finished,

I turned on the recorder and I got two sets of calls,

one which went "wah-wah" with two,

and one, "wah-wah-wah", with three.

And when we came back I joined the two together so they ran

and we could play it throughout the display.

And after the show had gone out, I got a letter from my old

professor of zoology, and he said, "Many congratulations on this

wonderful documentation of bird of paradise displays.

But had I noticed that, in fact, this bird did its two-note call

and then its three-note call, alternating, never two together,

then three together.

Would I perhaps write a learned paper

about this strange phenomenon?"

I had to explain to him that, actually,

it was a limitation of early natural history photography.

But the pictures produced by our primitive equipment

were black-and-white and fuzzy, so 40 years later, I made another

attempt to film the birds that Wallace had described so vividly.

As far as I know,

Wallace wasn't able to climb the tree to get a closer view

of the birds, but these days we have ways of doing so relatively simply.

You fire a thin line with a catapult over one of those higher

branches, haul up a thicker rope, attach a system of counterweights,

and all you have to do is clip yourself on and off you go.

And here's the top.

The birds are in another emergent tree, just like this one,

and I've got an absolutely clear view of them.

This, at last, is Wallace's picture come to life.

He was the first European to glimpse this extraordinary spectacle,

and he knew well, in general terms, what was happening.

This is a female, and she has come to pick

a mate from among the gorgeous males who are displaying.

The female has hopped on to the perch of the male of her choice,

that's a straight invitation to mate.

This is all he does as a father.

Now she'll fly away and raise her young unaided.

The females are comparatively drab.

It's only the male that have extravagant plumes.

Each of the 40 of species has its own kind.

Growing them and displaying them

must take a huge amount of a male's energy.

Can it really be worth all this just to mate with a female?

Well, it seems that it is.

At least for the male who puts on the most impressive performance,

for he will mate with virtually all the females in the area.

So, generation after generation, it is

only the winner whose genes are passed on,

and it is this, over many generations,

that produces such great extravagance of plumage and display.

It's a process known as sexual selection.

The males of another family of New Guinea birds

impress their females not with feathers, but with brightly

coloured objects, which they collect and display in bowers.

And this is the work of the master builder among bowerbirds.

I'm in the Vogelkop on the far western tip of New Guinea,

and this is the bower of the Vogelkop bowerbird.

And what an astonishment it is,

surely one of the wonders of the natural world.

The bower has been completely roofed over.

Their orange fruit, these glowing orange dead leaves,

and behind me there are black fruits

All of which has been bought specially by the bird.

A further step in our understanding of such spectacular behaviour

came in 1976 when Richard Dawkins published this book,

The Selfish Gene.

In it he brings together evolution, genetics and animal behaviour,

and argues that it is that the gene that drives evolution.

The survival of an individual animal is of less importance

than the survival of its genes.

And thinking about selection at the level of the gene

also enables us to understand why it is that some animals,

sometimes, behave in an unselfish way.

These ants are all female. And they are prepared... Ow!

They're prepared to attack me in defence of their colony

and to die in the process, because the genes that they carry are

the same as their sister workers and indeed, their mothers.

So in attacking me they are, in fact, doing their best to help

ensure that their genes are passed to the next generation.

You don't have to breed yourself to pass on your own genes.

All the female worker and soldier ants in this nest are sisters,

and they share 75% of their genes.

So the colony acts as a kind of single super-organism,

and, amazingly, it was discovered that some mammals

live in a similar kind of community.

Meerkats in the Kalahari Desert.

They spend the night in burrows,

they find all the food they need on the ground.

They are swift and expert runners.

But, oddly enough, they also climb,

and they have very good reasons for doing so.

But, first of all, they have to warm up in the early morning sun.

They live in groups in which the only dominant pair breeds,

and some of their offspring, even when adult, do not breed

but stay around to help rear the young.

While one helper watches out for danger, another catches a scorpion

and encourages one of the youngsters to eat it.

These helpers appear to be very unselfish,

but they're acting this way, probably because they share the same genes

as their charges and by helping them,

they're ensuring the transmission of those genes to the next generation.

The first meerkat film we made turned these animals

into stars, not, I must admit, because of their selfish genes,

but because of their enchanting personalities.

The factors that make these animals behave in the way they do

are transmitted in their genes.

But what kind of physical structure

could carry all this information?

That was one of the great puzzles

that had intrigued geneticists ever since

the beginnings of their science a century ago.

But that mystery too was about to be solved.

In 1953, here in the Cavendish Laboratories,

two young researchers, Francis Crick and James Watson

were building models like this.

It was their way of thinking about and investigating the structure

of a complex molecule that's found in the genes of all animals,

DNA.

The crucial bit are these chains

which encircle the rod, one...

and here is the second and entwine.

This is the double helix.

An extraordinary feat of intellectual deduction.

And it led to a whole new branch of science,

molecular genetics.

More recently, DNA has given us new insights

into the family relationship of animals

using a technique called DNA finger-printing.

It was developed by Sir Alec Jeffreys

of Leicester University in 1984.

And using just a simple smear of blood it's possible not only

to identify one particular individual,

but to establish whether or not it's closely related to another.

For example, we used to think

that most birds lived in straightforward pairs.

We watched them courting and mating

and rearing their young and so we assumed

that they were faithful to one another.

But DNA fingerprinting showed us how wrong we were.

As I explained in The Life of Birds.

Perhaps the most

bizarre behaviour of all

takes place in the suburban gardens of England.

And it seems that until very recently, nobody even noticed.

A young female hedge sparrow, a dunnock, ready to lay.

This is her mate, Alpha,

singing lustily, declaring his ownership of the nest

and the territory around it from which he gathers food.

The pair often feed together, a devoted couple if ever you saw one.

He seldom lets her out of his sight,

but she is not as faithful as she might be...

There's a third bird around,

Beta, another younger male.

He's not popular with Alpha and they're continually squabbling.

Sometimes the fights can get quite vicious and feathers fly.

But in spite of that, Beta stays around,

skulking in the hedge.

Alpha, it seems, has the female to himself once more.

But she has got her eye cocked.

Beta is still in the hedge, calling quietly to her.

She joins him.

And now, while Alpha is preoccupied with feeding,

she and Beta get together.

Twirling her tail is an invitation and, in a split second, they mate.

Beta flies away.

But now, out in the open,

she is courting Alpha with that same old tail twirling.

And now, he mates with her.

She has kept two males happy,

both of whom will help to feed the young when they hatch.

DNA fingerprinting has now revealed

that only about a fifth of the apparently monogamous birds

are actually genuinely faithful to one another.

Molecular genetics combined with long-term studies

of animals in the wild have challenged our preconceptions

about how animals live their lives.

And there are also long-term studies that have shed light

on our own evolution and ancestry,

in particular, those by Jane Goodall,

who started her work in 1960 in Tanzania on chimps.

The 26-year-old Jane Goodall arrived in Africa

with no scientific training

and had to patiently follow the chimps for two years

before they allowed her to get close to them.

In order to identify them,

she gave them the sort of names we use for one another,

which got her into a lot of trouble with more conventional scientists,

who accused her of crediting her animals with human characteristics,

for which there was no evidence.

But she made some revolutionary discoveries,

including proving that chimps use tools

and even modify them for particular purposes.

They fish for termites with twigs,

which they make more effective by stripping off the leaves.

Manufacturing tools in such a way had, until then,

been thought to be something that only human beings could do.

But in the late 1970s,

chimps on the other side of the continent, in West Africa,

were discovered using different tools in a different way.

Placing the nuts in a hole in the root,

they crack them open with specially selected hammers.

Repeated use has deepened the hole

and produced an anvil, which holds the nut in place.

Using these tools, experienced chimps can crack two nuts a minute.

For the hardest nuts, they keep and transport rare stone hammers.

Cracking is not easy.

You have to choose both a good anvil...

..and a good hammer.

Only West African chimpanzees have developed this nut-cracking ability,

and it takes more than ten years to learn the technique.

It's now known that chimps use up to 20 different types of tools.

Nut-cracking was first discovered by Christophe Boesch,

who had been studying these chimps since 1976.

And in 1989, I went out to the Ivory Coast to visit him.

How did you manage to get these animals so accustomed to you,

so that we could stand as close to them as this?

Oh, just patience.

- It took us five years. - Five years?

Five years, just following them, being always very quiet,

never aggressive, always the same colours and clothes

and patience, patience.

But Christophe wasn't entirely sure

that he wanted a 63-year-old with him in the forest.

- IN FRENCH ACCENT: - "Who is this old man?", he said,

"Who is this old man who want to come?"

"Is he fit? Can he run?"

The answer to those was no, on both,

but, nonetheless, I managed to get there.

And his technique was that he would travel with them all day,

wherever they went, and when they moved, he moved.

And he didn't leave them until they had made their nests at night.

And only then would he go back to his camp,

but then get up at four o'clock the next morning

in order to run back there and sketch them

before they went off again.

And he was... Christophe was quite right...

I mean, it's hugely demanding. I've never been so tired in all my life.

But Christophe had also discovered a darker side

to chimps' personalities.

You don't normally think of them as hunters.

More as...gentle vegetarians,

munching fruit and picking leaves.

But if you follow them for any length of time in their true home,

these forests in West Africa,

you discover that they ARE hunters.

What's more, they hunt in teams

and have a more complex strategy than any other hunting animal

except...

CHIMP SCREECHES LOUDLY

..except, of course...

man.

The technique they will almost certainly use

is that one of them will be driving the Colobus ahead of him

and there will be others that go up on either side, who are blockers,

who won't make any attempt to catch the monkeys,

and then there are chasers, who go and grab at the monkey if they can

and, finally, there's one male who will go up ahead and ambush it.

So, bringing the whole trap closed.

The monkeys are now getting alarmed.

A driver's going up, to prevent the group from settling

and to drive them towards an area where they're more easily trapped.

Now, it looks as though they're all in position.

The drivers have gone up, the blockers have gone up and now,

the one who's going to make the ambush and close the ring,

he's gone up too.

The Colobus will be very lucky if they escape now.

RUSTLING

MONKEYS SCREECH

They've got one!

And now, the kill is brought down,

so that the females and others can share it.

And there's the reward for that long chase.

The divided body of a Colobus monkey.

These...

blood-stained faces...

may well horrify us.

But we might also see in them

the face of our long-distant hunting ancestors.

And if we are...

appalled...

by that mob violence and blood lust,

we might also see in that too, perhaps,

the origins of the teamwork...

that have, in the end,

brought human beings many of their greatest triumphs.

But the studies of chimpanzees

started by Jane Goodall, continued by Christophe Boesch and others

have shown us something else.

It's not just that chimpanzees are capable

of developing their own techniques for hunting or tool-making,

but that each community of chimps

is capable of developing its own version.

In other words, chimpanzees' communities have their own cultures.

And that was thought to be something that was uniquely human.

Everyone knew, of course, that chimps are our biological cousins,

but it's only in the last 20 years that we've discovered

that we share of about 95% of our DNA with them.

And that's because we now have the tools to find out

exactly how closely we are all related.

In 1990, scientists in 20 labs around the world

set out to identify all the 3,000 million separate chemical units

that make up the human genetic code.

It took nearly 13 years, and then,

exactly 50 years after Crick and Watson had worked out

the structure of DNA,

the human genome was cracked.

And this is it.

In these volumes is all the information needed

to define the genetic structure of the human species.

Each number refers to one of our 23 chromosomes.

If I open it up,

you can see that the text consists of

just one very, very, very long list of just four letters...

A, C, T, G.

Each combination represents instructions

for one element in the human design.

This is the secret language of DNA.

This is the book of life.

And each one of us has our own edition.

When I first heard, back in 1953,

that the structure of DNA had been worked out,

I could scarcely have imagined that it would ever be possible

to print out the whole of one genome in a book.

But, today, the process has been so speeded up,

that it's possible for anyone to have it done in half a day.

And the comparison between the genome of one species and another

has proved very revealing.

The hot chemical springs of Yellowstone

contain the very simplest form of life, single-celled bacteria,

about as far removed from our complex selves

as any organism could be.

But we share some 200 of our genes with those very early life forms.

Indeed, there are some genes

that are common to every single species of life on the planet.

Our DNA extends in an unbroken chain

right to the beginning of life, 4,000 million years ago.

So, now, we can trace our evolutionary heritage

back through geological time.

Back to the age of dinosaurs...

..and further still to the early amphibians.

Back to the fish...

..and the first back-boned animals.

And further still, to the single-celled organisms

that were the very earliest form of life to appear on this planet.

So, in my lifetime, science has solved many of the riddles

which, 60 years ago, seemed so baffling.

How mountain ranges are formed.

Why animals are distributed in the way they are,

and how they communicate with one another.

How a complex chemical molecule

can transfer the characteristics of one generation to the next.

It's even shed some light on that deepest of mysteries,

the very origin of life.

So, now, the natural world makes more sense than it ever did,

which is why studying it is so rewarding and so delightful.

I've lived through an era

of extraordinary scientific discoveries.

But we've also, in that time,

profoundly changed the way we view the natural world.

And that will be the subject of next week's programme.

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