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Our Earth is the only known planet
that sustains life,

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and it does so in abundance.

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I have been fortunate enough,
over the years,

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to travel to some of the most
extraordinary and remote places
on Earth

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to find and film animals.

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This is the biggest
flower in the world.

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The blue whale!

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It's the biggest creature
that exists on the planet.

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The sheer number and variety of
animals and plants is astonishing.

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Estimates of the number of
different species vary from
six million to 100 million.

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Nobody knows how many different
kinds of animals there are here.

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Wherever you look, there's life.

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There are often a multitude of
variations on a single pattern -

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nearly 200 different kinds
of monkeys, for example.

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And 315 hummingbirds.

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Nearly a thousand bats.

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And beetles...
at least 350,000 species of them.

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Not to mention
a quarter of a million
different kinds of flowering plants.

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The variety is astounding.

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HE CHUCKLES

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Even in this one small
English woodland,

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you might see four or five
different kinds of finches.

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Why should there be such
a dazzling variety?

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And how can we make sense of such
a huge range of living organisms?

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200 years ago,

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a man was born who was to explain
this astonishing diversity of life.

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In doing so, he revolutionised
the way in which we see the world

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and our place in it.

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His name was Charles Darwin.

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This book, the Holy Bible,

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explains how this wonderful
diversity came about.

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On the third day after the creation
of the world, God created plants.

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On the fifth day, fish and birds,

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and then on the sixth day, mammals,

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and finally, man.

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That explanation was believed,
literally,

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by pretty well
the whole of Western Europe
for the best part of 2,000 years,

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and generations of painters
pictured it for the faithful.

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This version was painted in
Italy in the 16th century.

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Here is God in the Garden of Eden,

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which is now filled
with all kinds of animals.

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Here he is pulling Adam
out of the Earth.

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And here, creating the first
woman by putting Adam to sleep,

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and then taking one of his ribs
and extracting Eve from his side.

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She comes out,
assisted by two angels.

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And when God had finished,
he said to Adam and Eve,

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"Be fruitful and multiply and
replenish the earth and subdue it,

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"and have dominion
over the fish of the sea
and over the fowl of the air,

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"and over every living thing
that moveth upon the Earth."

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That made it clear that,
according to the Bible,

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humanity could exploit
the natural world as they wished.

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This view of mankind's superiority
still stood when, in 1831,

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a British surveying ship,
the Beagle, set off on a voyage
around the world.

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On board,
as a companion to the captain,

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was the 22-year-old Charles Darwin.

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They crossed the Atlantic and made
landfall on the coast of Brazil.

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There, the sheer abundance
of tropical nature
astonishes the newcomer,

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as I discovered when I retraced
Darwin's steps 30 years ago

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for a television series about
the diversity of nature.

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Darwin, as a boy, had been a
fanatical collector of insects,

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and here he was enthralled,
almost to the point of ecstasy.

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In one day, in a small area,

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he discovered
69 different species of beetle.

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As he wrote in his journal,

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"It's enough to disturb the
composure of the entomologist's mind

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"to contemplate the future
dimension of a complete catalogue."

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They went south, rounded Cape Horn
and so reached the Pacific.

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And then, in September 1835,

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after they had been away
for almost four years,

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they landed on the little-known
islands of the Galapagos.

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Here they found creatures that
existed nowhere else in the world.

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Cormorants
that had lost the power of flight.

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Lizards that swam out
through the surf

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to graze on the bottom of the sea.

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Darwin, who had studied botany and
geology at Cambridge University,

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collected specimens of
the animals and plants,

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and as usual,
when he went ashore to investigate,

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described what he
found in his journal.

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"My servant and self were landed
a few miles to the northeast,

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"in order that I might examine
the district mentioned above

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"as resembling chimneys."

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Volcanic chimneys, presumably.

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"The comparison
would have been more exact

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"if I had said, 'the iron
furnaces near Wolverhampton.' "

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HE CHUCKLES

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The British resident
in the Galapagos

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claimed that he knew from the
shape of a giant tortoise's shell,

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which island it had come from.

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If it had a rounded front,

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it came from a well-watered island,
where it fed on lush ground plants.

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Whereas one from a drier island
had a peak at the front,

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which enabled it to reach up
to higher vegetation.

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Were these tortoises, each on their
separate islands, different species?

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And if so, was each one
a separate act of divine creation?

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The differences
that Darwin had noticed

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amongst these Galapagos animals
were, of course, all tiny,

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but if they could develop,

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wasn't it possible that over the
thousands or millions of years

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a whole series of such differences
might add up

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to one revolutionary change?

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On his voyage home, Darwin had
time to ponder on these things.

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Could it be that species
were not fixed for all time,
but could, in fact, slowly change?

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On his return, he sorted out
his specimens and sent them off

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to relevant experts so that each
could be identified and classified.

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Most of the mammal bones and fossils
he sent to Richard Owen.

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Owen was one of the most
brilliant zoologists of his time.

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He was the first
to recognise dinosaurs,

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and indeed had
invented their very name,

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and he would later become the
creator and first director of the
Natural History Museum in London.

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Many of the specimens that Darwin
collected are still preserved
and treasured

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here among the 70 million
other specimens housed
in the museum that Owen founded.

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And here is one of them.

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It's obviously the lower jaw of
some great animal,
and when Darwin discovered it,

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it had bits of
skin and hair attached to it,

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so that at first it was thought
to be the remains of
some unknown living species.

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But now we know that it is a species
that was extinct for some 10,000
years, a giant ground sloth.

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Owen examined it in great detail

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and eventually described it and gave
it the name of Mylodon darwinii,

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in honour of its discoverer.

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But that mutual respect
between two great men of science
was not to last.

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Soon after his return from his
voyage, Darwin made his home here,
in Down House, in Kent.

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Here he wrote an account
of his travels

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and worked on detailed
scientific treatises about corals

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and barnacles and the geology
and fossils of South America.

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But he also pondered deeply
on what he had seen in the Galapagos
and elsewhere.

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Maybe species were not fixed.

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Every day, he took a walk
in this small spinney

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that he had planted
at the end of his garden.

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And it was here that he came to
ponder on the problems of
natural history,

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including that
mystery of mysteries -

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how could one species
turn into another.

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He noted that most,
if not all, animals

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produce many more young
than live to breed themselves.

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This female blue tit, for example,
may well lay a dozen eggs a year -

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perhaps 50 or so in her lifetime.

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Yet only two of her chicks need
to survive and breed themselves

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to maintain the numbers
of the blue tit population.

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Those survivors, of course,
are likely to be the healthiest

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and best suited
to their particular environment.

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Their characteristics
are then inherited.

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So perhaps, over many generations,

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and particularly if there are
environmental changes,
species may well change.

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Only the fittest survive,
and that was the key.

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He called the process
"natural selection".

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That would explain the differences
that he had noted in the finches

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that he had brought back
from the Galapagos.

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They were very similar,
except for their beaks.

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This one has a very thin, delicate
beak which it uses to catch insects.

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This one, on the other hand,

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which came from an environment
where there were a lot of nuts,

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has a big, heavy beak
which enables it to crack them.

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So maybe,

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over the vastness
of geological time,

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and particularly if species
were invading new environments,

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those changes would amount to
very radical changes indeed.

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Darwin drew a sketch in one of his
notebooks to illustrate his idea,

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showing how a single ancestral
species might give rise to
several different ones,

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and then wrote above it
a tentative "I think".

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Now he had to prove his theory,

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and he spent years gathering
abundant and convincing evidence.

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He was an extraordinary
letter writer.

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He wrote as many as a dozen letters
a day to scientists and naturalists
all over the world.

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He also realised,

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that when people had first started
domesticating animals,

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they had been doing
experiments for him - for centuries.

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All domestic dogs are descended
from a single ancestral species -
the wolf.

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Dog breeders select those pups
that have the characteristics
that happen to please them.

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Nature, of course, selects those
young animals that are best suited
to a particular environment,

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but the process
is essentially the same,

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and in both cases
it has produced astonishing variety.

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In effect,
many of these different breeds

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could be considered different
species because they do not,
indeed they cannot, inter-breed.

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For purely mechanical reasons,
there's no way in which a Pekingese
can mate with a Great Dane.

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Of course, it's true that
if you used artificial insemination,

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you could get crosses
between almost any of these breeds,

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but that's because human beings
have been selecting between dogs

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for only a few centuries.

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Nature has been selecting between
animals for millions of years -

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tens of millions,
even hundreds of millions of years,

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so what might have started out
as we would consider to be breeds

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have now become so different
they are species.

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Darwin, sitting in Down House,
wrote to pigeon fanciers and
rabbit breeders,

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asking all kinds of
detailed questions
about their methods and results.

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He himself, being a country
gentleman and running an estate,

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knew about breeding
horses and sheep and cattle.

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And he also conducted
careful experiments with
plants in his greenhouse.

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But Darwin knew that the idea that
species could appear without divine
intervention

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would appal society in general,

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and it was also contrary
to the beliefs of his wife, Emma,

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who was a devout Christian.

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Perhaps for that reason,
he was keen to keep the focus
of his work scientific.

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He made a point
of not being drawn in public
about his religious beliefs,

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but in the latter part of his life,
he withdrew from attending church.

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On Sundays, he would escort Emma
and the children here to
the parish church in Down,

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but while they went
into the service,

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he remained outside and went for
a walk in the country lanes.

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Perhaps because he feared that his
theory would cause outrage
in some quarters,

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he delayed publishing it
year after year after year.

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But he wrote a long abstract of it,

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and then on July 5th 1844,
he wrote this letter to his wife.

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"My dear Emma.

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"I have just finished this
sketch of my species theory..."

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Some sketch - it was 240 pages long.

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"I therefore write this
in case of my sudden death,

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"that you will devote
£400 to its publication."

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He then goes on to list his
various naturalist friends

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who would be asked to edit it
and check it,

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and he ends the letter charmingly,

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"My dear wife...

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"yours affectionately, CR Darwin."

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He continued to accumulate
evidence and refine his theory
for the next 14 years.

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But then, his hand was forced.

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In June 1858, 22 years after he got
back from the Galapagos,

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here in his study in Down,
he received a package

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from a naturalist who was working
in what is now Indonesia.

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His name was Alfred Russell Wallace.

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He had been corresponding
with Darwin for some years.

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But this package was different.

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It contained an essay that set out
exactly the same idea as Darwin's...

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of evolution by natural selection.

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The idea had come to Wallace
as he lay in his hut,
semi-delirious in a malarial fever.

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But although his idea of natural
selection was the same as Darwin's,

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he had not spent 20 years gathering
the mountain of evidence to
support it, as Darwin had done.

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But whose idea was it?

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In the end, the senior members of
the Linnean Society decided that
the fairest thing

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was for a brief outline of the
theory from each of them to be
read out, one after the other,

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at a meeting of the society,
here in Burlington House in London.

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The Linnean, then as now,

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was the place where scientists
studying the natural world
held regular meetings

230
00:20:25,140 --> 00:20:29,260
to present and discuss papers about
their observations and thoughts.

231
00:20:31,140 --> 00:20:38,900
The one held on July 1st 1858 was
attended by only about 30 people.

232
00:20:38,900 --> 00:20:41,660
Neither of the authors were present.

233
00:20:41,660 --> 00:20:45,420
Wallace was 10,000 miles away
in the East Indies,

234
00:20:45,420 --> 00:20:52,540
and Darwin was ill
and devastated by the death a
few days earlier of his infant son,

235
00:20:52,540 --> 00:20:55,940
so he was still at his home in Kent.

236
00:20:55,940 --> 00:21:00,820
As a consequence, the two papers
had to be read by the secretary,

237
00:21:00,820 --> 00:21:06,260
and as far as we can tell, they made
very little impression on anyone.

238
00:21:08,340 --> 00:21:12,300
Darwin spent the next year
writing out his theory in detail.

239
00:21:12,300 --> 00:21:16,740
Then he sent the manuscript to
his publisher, John Murray,

240
00:21:16,740 --> 00:21:23,140
whose firm - then as now - had
offices in Albemarle Street,
just off Piccadilly in London.

241
00:21:23,140 --> 00:21:27,420
Murray was
the great publisher of his day

242
00:21:27,420 --> 00:21:31,260
and dealt with the works of
Jane Austen and Lord Byron,

243
00:21:31,260 --> 00:21:35,220
whose first editions still
line these office walls.

244
00:21:35,220 --> 00:21:39,220
Darwin regarded his work
as simply a summary,

245
00:21:39,220 --> 00:21:42,060
but even so, it is 400 pages.

246
00:21:42,060 --> 00:21:47,340
It was published
on November 24th 1859.

247
00:21:47,340 --> 00:21:51,300
This is not a
first edition, more's the pity.

248
00:21:51,300 --> 00:21:55,220
First editions are worth literally
hundreds of thousands of pounds.

249
00:21:55,220 --> 00:21:58,300
This is a 6th edition - my copy,

250
00:21:58,300 --> 00:22:02,780
which I bought as a boy,
when I was 18, I notice.

251
00:22:02,780 --> 00:22:05,780
And it cost me the princely sum
of one shilling.

252
00:22:10,540 --> 00:22:15,820
The first edition of 1,250 copies
sold out immediately,

253
00:22:15,820 --> 00:22:17,740
and it went for a reprint.

254
00:22:17,740 --> 00:22:20,260
And then another reprint
and another reprint.

255
00:22:20,260 --> 00:22:26,020
It's a book that contains
very few technical terms -
it's easily understood by anybody.

256
00:22:26,020 --> 00:22:29,980
And predictably,
it caused an outrage,

257
00:22:29,980 --> 00:22:34,020
not only throughout this country,
but indeed all the civilised world.

258
00:22:37,340 --> 00:22:40,980
What scandalised people most,
it seems, was the implication

259
00:22:40,980 --> 00:22:44,900
that human beings
were not specially created by God,

260
00:22:44,900 --> 00:22:46,460
as the Book of Genesis stated,

261
00:22:46,460 --> 00:22:49,900
but were descended
from ape-like ancestors -

262
00:22:49,900 --> 00:22:54,580
a notion that provided a
lot of scope for cartoonists.

263
00:22:56,420 --> 00:23:00,820
The leaders of the Church,
headed by Samuel Wilberforce,
the Bishop of Oxford,

264
00:23:00,820 --> 00:23:03,740
attacked it on the grounds
that it demoted God

265
00:23:03,740 --> 00:23:07,660
and contradicted the story of
Creation as told by the Bible.

266
00:23:09,820 --> 00:23:14,260
"That Mr Darwin should have
wandered from this broad highway

267
00:23:14,260 --> 00:23:20,380
"of nature's works
into the jungle of fanciful
assumption is no small evil."

268
00:23:20,380 --> 00:23:23,420
"I have read your book with more
pain than pleasure..."

269
00:23:23,420 --> 00:23:28,060
"It is the frenzied inspiration
of the inhaler of mephitic gas."

270
00:23:28,060 --> 00:23:29,580
"Fails utterly."

271
00:23:33,780 --> 00:23:38,860
Darwin's theory implied that life
had originated in simple forms,

272
00:23:38,860 --> 00:23:42,500
and had then become
more and more complex.

273
00:23:42,500 --> 00:23:49,140
He knew perfectly well
that the whole idea of evolution
raised a lot of questions.

274
00:23:49,140 --> 00:23:55,100
In fact, some of those questions
would not be answered until
comparatively recently.

275
00:23:55,100 --> 00:23:58,140
But in his own time,
many distinguished scientists

276
00:23:58,140 --> 00:24:02,620
raised what seemed to be
insuperable difficulties.

277
00:24:02,620 --> 00:24:05,740
And foremost among them
was Richard Owen,

278
00:24:05,740 --> 00:24:12,260
the man who 20 years earlier had
named the extinct ground sloth
in honour of Darwin.

279
00:24:14,020 --> 00:24:19,820
Over the years, the two men
had developed a deep
personal dislike of one another

280
00:24:19,820 --> 00:24:23,020
and had quarrelled frequently.

281
00:24:23,020 --> 00:24:28,860
It wasn't that Owen thought that
the story of the Garden of Eden
was literally correct,

282
00:24:28,860 --> 00:24:32,780
but nonetheless,
he was a deeply religious man.

283
00:24:38,860 --> 00:24:45,620
He had, after all, ensured that
his museum, which would display
the wonders of Creation,

284
00:24:45,620 --> 00:24:51,140
echoed in its design the great
Christian cathedrals of
medieval Europe.

285
00:25:00,300 --> 00:25:04,140
And Owen knew about
the diversity of life.

286
00:25:04,140 --> 00:25:07,900
Indeed, he had spent his
whole career cataloguing it.

287
00:25:07,900 --> 00:25:12,660
But even so, he refused to believe
that a species could change
over time.

288
00:25:15,140 --> 00:25:18,580
He, and other pioneer
Victorian geologists,

289
00:25:18,580 --> 00:25:21,860
as they established
their comparatively new science,

290
00:25:21,860 --> 00:25:26,500
recognised that the outlines of the
history of life could be deduced

291
00:25:26,500 --> 00:25:29,180
by examining the land around them.

292
00:25:31,380 --> 00:25:35,340
Look at these rocks
in northern Scotland.

293
00:25:35,340 --> 00:25:41,220
We know from fossils that
are associated with them
that they are very ancient.

294
00:25:41,220 --> 00:25:43,380
And they are sand stones.

295
00:25:43,380 --> 00:25:47,460
Compacted sand that was laid
down at the bottom of the sea,

296
00:25:47,460 --> 00:25:51,100
layer upon layer upon layer.

297
00:25:51,100 --> 00:25:53,500
But look how many layers there are!

298
00:26:09,980 --> 00:26:12,980
Clearly, those at the top
must have been laid down

299
00:26:12,980 --> 00:26:15,780
after those beneath them.

300
00:26:15,780 --> 00:26:22,180
So as you descend from layer to
layer, you are in effect
going back in time.

301
00:26:22,180 --> 00:26:26,820
So a fossil species,
if it comes from a particular layer,

302
00:26:26,820 --> 00:26:29,340
is of a particular age.

303
00:26:29,340 --> 00:26:36,580
And if you can recognise each one,
then you can begin to piece together
the outlines of life's history.

304
00:26:39,420 --> 00:26:41,060
Ah, Micraster...

305
00:26:41,060 --> 00:26:45,940
The ability to identify fossils
and place them in their
geological time zone

306
00:26:45,940 --> 00:26:52,260
was still an essential skill when I
was at university a century later.

307
00:26:52,260 --> 00:26:55,980
We worked our way through drawers
like these,

308
00:26:55,980 --> 00:26:58,940
which are full of fossils
of one sort or another -

309
00:26:58,940 --> 00:27:02,780
but none of them
have labels, only numbers.

310
00:27:02,780 --> 00:27:06,820
So you were expected
to be able to pick up one...

311
00:27:08,100 --> 00:27:11,860
..and say,
"Yes, that's a belemnite."

312
00:27:11,860 --> 00:27:14,900
Now, actually which belemnite
it is, I can't remember now.

313
00:27:14,900 --> 00:27:18,860
And when you came to
your practical exam,

314
00:27:18,860 --> 00:27:21,660
your examiners would produce
one of these and say,

315
00:27:21,660 --> 00:27:23,740
"OK, what's that?"

316
00:27:23,740 --> 00:27:25,900
And you either knew
or you didn't,

317
00:27:25,900 --> 00:27:32,220
and the way you knew was because of
all the work you did in drawers
like these, hour after hour.

318
00:27:37,260 --> 00:27:42,220
Owen did not deny the sequence
in which all these different
species appeared.

319
00:27:42,220 --> 00:27:47,700
But he believed that each was
separate, each divinely created.

320
00:27:47,700 --> 00:27:53,900
Darwin's theory, however, required
that there should be connections
not just between similar species,

321
00:27:53,900 --> 00:27:56,420
but between the great animal groups.

322
00:27:58,820 --> 00:28:04,900
If fishes and reptiles and birds
and mammals had all evolved
from one another,

323
00:28:04,900 --> 00:28:10,540
then surely there must be
intermediate forms
between those great groups.

324
00:28:10,540 --> 00:28:12,620
And they were missing.

325
00:28:12,620 --> 00:28:18,580
And then, just two years after
the publication of
The Origin Of Species,

326
00:28:18,580 --> 00:28:25,340
Richard Owen himself purchased
the most astonishing fossil
for his museum.

327
00:28:27,460 --> 00:28:32,180
It had been found in this
limestone quarry in Bavaria.

328
00:28:32,180 --> 00:28:35,220
The stone here splits into
flat, smooth leaves

329
00:28:35,220 --> 00:28:39,500
that have been used
as roofing tiles since Roman times.

330
00:28:41,940 --> 00:28:43,700
Most are blank.

331
00:28:43,700 --> 00:28:47,380
But occasionally,
when you split them apart,

332
00:28:47,380 --> 00:28:50,660
they reveal a shrimp or a fish.

333
00:28:50,660 --> 00:28:54,580
It's almost impossible to
resist the temptation

334
00:28:54,580 --> 00:28:58,420
of pulling down
almost every boulder you see,

335
00:28:58,420 --> 00:29:03,460
and then opening it like a book,
to look at each unopened page

336
00:29:03,460 --> 00:29:08,260
to see whether maybe
it contains yet another fossil.

337
00:29:13,900 --> 00:29:17,700
But this fossil
was something unprecedented.

338
00:29:17,700 --> 00:29:23,700
It is still one of the greatest
of the treasures that are stored
in the Natural History Museum.

339
00:29:24,980 --> 00:29:29,860
And this is it -
it's called archaeopteryx.

340
00:29:29,860 --> 00:29:34,100
It has unmistakable feathers
on its wings

341
00:29:34,100 --> 00:29:36,980
and down its tail.

342
00:29:36,980 --> 00:29:41,380
So Owen had no hesitation
in calling it a bird.

343
00:29:41,380 --> 00:29:45,100
But it was unlike any other bird
that anyone knew of,

344
00:29:45,100 --> 00:29:49,580
because it had
claws on the front of its wings,

345
00:29:49,580 --> 00:29:54,420
and, as was later discovered,
it didn't have a beak,
but jaws with teeth in it.

346
00:29:54,420 --> 00:29:59,300
And a line of bones
supporting its tail.

347
00:29:59,300 --> 00:30:03,740
So it was part reptile, part bird.

348
00:30:04,820 --> 00:30:08,460
Here was a link
between those two great groups

349
00:30:08,460 --> 00:30:11,100
that was no longer missing.

350
00:30:11,100 --> 00:30:15,420
Gosh, you really can see
the filaments there.

351
00:30:21,100 --> 00:30:27,340
Other examples of the same creature
show its feathers even more clearly.

352
00:30:27,340 --> 00:30:34,260
We know from the bones
of archaeopteryx that it was,
at best, a very poor flyer.

353
00:30:34,260 --> 00:30:38,540
So it's not surprising that
eventually it was superseded

354
00:30:38,540 --> 00:30:41,620
by more modern,
more efficient birds.

355
00:30:41,620 --> 00:30:46,940
And that's the fate of these
links between great groups.

356
00:30:46,940 --> 00:30:49,340
Eventually they become extinct,

357
00:30:49,340 --> 00:30:54,540
and the only way we know
they existed is from
their fossilised remains.

358
00:30:54,540 --> 00:30:58,420
Even so, there is a bird alive today

359
00:30:58,420 --> 00:31:04,500
that illustrates the link
between modern birds and reptiles.

360
00:31:07,780 --> 00:31:11,380
The hoatzin nests in the
swamps of tropical South America.

361
00:31:11,380 --> 00:31:17,460
There are cayman in the water
beneath, ready to snap up any chick
that might fall from its nest,

362
00:31:17,460 --> 00:31:19,940
so an ability to hold on
tight is very valuable.

363
00:31:19,940 --> 00:31:23,900
And the nestlings have a very
interesting way of doing that.

364
00:31:24,980 --> 00:31:30,940
The young still have claws on
the front of their wings,
as archaeopteryx did.

365
00:31:30,940 --> 00:31:35,380
Here is vivid evidence that the
wings of birds are modified forelegs

366
00:31:35,380 --> 00:31:38,220
and once had toes
with claws on them.

367
00:31:39,260 --> 00:31:44,260
There's another creature alive today
that represents a link between the
great animal groups,

368
00:31:44,260 --> 00:31:48,980
a descendant of a group of reptiles
that took a different
evolutionary course

369
00:31:48,980 --> 00:31:52,420
and evolved not feathers, but fur -

370
00:31:52,420 --> 00:31:54,300
the platypus.

371
00:31:54,300 --> 00:31:58,620
When specimens of this creature
first reached Europe from Australia

372
00:31:58,860 --> 00:32:00,980
at the very end of the
18th century,

373
00:32:00,980 --> 00:32:04,740
people refused to
believe their eyes.

374
00:32:04,740 --> 00:32:07,300
They said it was a hoax -

375
00:32:07,300 --> 00:32:12,820
bits and pieces of
different creatures
rather crudely sewn together.

376
00:32:12,820 --> 00:32:15,860
And yet in a way
those early sceptics were right.

377
00:32:15,860 --> 00:32:20,460
The platypus is the most
extraordinary mixture
of different animals.

378
00:32:20,460 --> 00:32:23,940
It's part mammal and part reptile.

379
00:32:23,940 --> 00:32:27,580
And so it can give us some idea
of how the first mammals developed.

380
00:32:29,140 --> 00:32:35,580
When it comes to breed,
it does something that separates it
from all other mammals except one.

381
00:32:35,580 --> 00:32:39,580
In its nest,
deep in a burrow, it lays eggs.

382
00:32:39,580 --> 00:32:43,060
It's this that links the
platypus with the reptiles,

383
00:32:43,060 --> 00:32:45,940
and this that entitles it
to be regarded

384
00:32:45,940 --> 00:32:49,100
as the most primitive
living mammal.

385
00:32:51,180 --> 00:32:53,980
So the links between
the great animal groups

386
00:32:53,980 --> 00:32:56,460
are not, in fact, missing,

387
00:32:56,460 --> 00:33:00,820
but exist both as fossils
and as living animals.

388
00:33:00,820 --> 00:33:05,580
Although the fossil record provides
an answer to the problem

389
00:33:05,580 --> 00:33:11,100
of missing links,
it also posed a major problem.

390
00:33:11,100 --> 00:33:13,700
It started very abruptly.

391
00:33:13,700 --> 00:33:16,740
The earliest known fossils in
Darwin's time

392
00:33:16,740 --> 00:33:20,700
came from a formation
called the Cambrian,

393
00:33:20,700 --> 00:33:22,860
and there were two main kinds -

394
00:33:22,860 --> 00:33:27,940
these, which look like fretsaw
blades and are called graptolite,

395
00:33:27,940 --> 00:33:32,620
and these, like giant woodlice,
which are called trilobites.

396
00:33:32,620 --> 00:33:36,260
Could it really be
that life on Earth started

397
00:33:36,260 --> 00:33:40,100
with creatures as complex as these?

398
00:33:54,740 --> 00:33:59,500
As a boy, I was a
passionate collector of fossils.

399
00:33:59,500 --> 00:34:02,860
I grew up in the city of Leicester,

400
00:34:02,860 --> 00:34:08,100
and I knew that in this area,
not far from the city,
called Charnwood Forest,

401
00:34:08,100 --> 00:34:13,740
there were the oldest rocks in the
world, older even than the Cambrian.

402
00:34:13,740 --> 00:34:18,180
So therefore, by definition,
they would be without fossils.

403
00:34:18,180 --> 00:34:23,260
There was no point in me looking
for fossils in these ancient rocks.

404
00:34:38,780 --> 00:34:41,860
There were, it's true,
very rarely,

405
00:34:41,860 --> 00:34:45,380
some rather odd shapes
in these rocks,

406
00:34:45,380 --> 00:34:47,700
like this one here.

407
00:34:47,700 --> 00:34:53,140
But they were dismissed as being
some kind of mechanical aberration.

408
00:34:53,140 --> 00:34:54,540
I mean, after all,

409
00:34:54,540 --> 00:34:59,620
how could there be anything living
in these extremely ancient rocks?

410
00:35:00,780 --> 00:35:04,260
And then in 1957,

411
00:35:04,260 --> 00:35:10,460
a schoolboy
with rather more patience
and perspicacity than I had

412
00:35:10,460 --> 00:35:13,700
found something really remarkable -

413
00:35:13,700 --> 00:35:18,380
and undeniably, the remains
of a living creature.

414
00:35:21,020 --> 00:35:23,700
And here it is
in Leicester Museum,

415
00:35:23,700 --> 00:35:26,740
where it's been
brought for safekeeping.

416
00:35:26,740 --> 00:35:29,580
It's called Charnia.

417
00:35:29,580 --> 00:35:35,860
Who could doubt that this is the
impression of a living organism?

418
00:35:35,860 --> 00:35:39,660
It has a central stem,
and branches on either side.

419
00:35:39,660 --> 00:35:43,980
In fact, it seems to have been
something like the sea pens

420
00:35:43,980 --> 00:35:47,500
that today grow on coral reefs.

421
00:35:47,500 --> 00:35:52,900
Since its discovery, a whole range
of organisms have been found

422
00:35:52,900 --> 00:35:56,420
in rocks of this extreme age,

423
00:35:56,420 --> 00:36:01,660
not only here in the Charnwood
Forest, but in many other
different parts of the world.

424
00:36:03,060 --> 00:36:08,180
Fossil hunters searching these rocks
in the Ediacra Hills of Australia

425
00:36:08,180 --> 00:36:11,420
had also been discovering other
strange shapes.

426
00:36:13,260 --> 00:36:16,660
At first, many scientists
refused to believe

427
00:36:16,660 --> 00:36:20,780
that these faint impressions
were the remains of jellyfish.

428
00:36:20,780 --> 00:36:24,460
But by now, enough specimens had
been discovered to make quite sure

429
00:36:24,460 --> 00:36:27,140
that that indeed is what they are.

430
00:36:35,220 --> 00:36:41,180
So now we know that life
did not begin suddenly with those
complex animals of the Cambrian.

431
00:36:43,700 --> 00:36:45,860
It started much, much earlier,

432
00:36:45,860 --> 00:36:50,820
first with simple microscopic forms
which eventually became bigger,

433
00:36:50,820 --> 00:36:56,020
but which were still so soft and
delicate that they only very
rarely left any mark in the rocks.

434
00:36:59,180 --> 00:37:04,860
The question of the age of the Earth
posed another problem for
Darwin's theory.

435
00:37:04,860 --> 00:37:11,380
In the 17th century, an Irish bishop
had used the genealogies
recorded in the Bible

436
00:37:11,380 --> 00:37:15,220
that lead back to Adam to work out
that the week of Creation

437
00:37:15,220 --> 00:37:19,900
must have taken place
in the year 4004 BC.

438
00:37:19,900 --> 00:37:23,340
That may seem to us to be a very
naive way of doing things,

439
00:37:23,340 --> 00:37:25,780
but what other method
was there anyway?

440
00:37:27,260 --> 00:37:33,100
The Victorian geologists had
already concluded that the Earth
must be millions of years old.

441
00:37:33,100 --> 00:37:37,380
But how many millions,
no-one could say.

442
00:37:37,380 --> 00:37:41,420
Then, less than 50 years after
the publication of The Origin,

443
00:37:41,420 --> 00:37:46,460
a discovery was made
in what seemed a totally
disconnected branch of science

444
00:37:46,460 --> 00:37:49,100
that would ultimately
provide the answer.

445
00:37:50,580 --> 00:37:53,820
A Polish woman
working in Paris, Marie Curie,

446
00:37:53,820 --> 00:37:58,700
discovered that some rocks contained
an element called uranium

447
00:37:58,700 --> 00:38:04,380
that decays over time
at a steady rate through a process
called radiation.

448
00:38:04,380 --> 00:38:09,420
Today, a century after she made
her extraordinary discovery,

449
00:38:09,420 --> 00:38:11,580
the method of dating by measuring

450
00:38:11,580 --> 00:38:15,580
changes in radioactivity
has become greatly refined.

451
00:38:19,460 --> 00:38:25,180
This is a sample taken from
those very ancient rocks
in Charnwood Forest.

452
00:38:25,180 --> 00:38:31,780
And these tiny crystals are revealed
to be 562 million years old.

453
00:38:31,780 --> 00:38:35,460
That provides more than enough time

454
00:38:35,460 --> 00:38:39,580
for natural selection to produce
the procession of fossils

455
00:38:39,580 --> 00:38:44,380
that eventually leads to the living
animals and plants we know today.

456
00:38:45,380 --> 00:38:47,860
But there was another objection.

457
00:38:47,860 --> 00:38:52,300
If all animals within a group
have a common origin,

458
00:38:52,300 --> 00:38:55,780
how is it that some
kinds of animals are distributed

459
00:38:55,780 --> 00:39:00,860
throughout the continents of
the world, except for Antarctica?

460
00:39:00,860 --> 00:39:06,340
How is it that, for example,
frogs in Europe and Africa

461
00:39:06,340 --> 00:39:09,380
are also found here
in South America,

462
00:39:09,380 --> 00:39:11,620
on the other side of the
Atlantic Ocean,

463
00:39:11,620 --> 00:39:17,700
bearing in mind that frogs
have permeable skins
and can't survive in sea water?

464
00:39:17,700 --> 00:39:21,380
Darwin himself
had a couple of suggestions.

465
00:39:21,380 --> 00:39:25,780
One was that they might have
floated across accidentally
on rafts of vegetation,

466
00:39:25,780 --> 00:39:30,700
and the other is that
maybe there were land bridges
between the continents,

467
00:39:30,700 --> 00:39:34,340
but even he was not convinced
by either explanation.

468
00:39:40,860 --> 00:39:47,380
Even as late as 1947, when I was a
geology student here at Cambridge,

469
00:39:47,380 --> 00:39:50,380
there was no convincing
explanation.

470
00:39:50,380 --> 00:39:56,220
It's true that back in 1912,
a German geologist had suggested

471
00:39:56,220 --> 00:40:00,140
that at one time
in the very remote, distant past,

472
00:40:00,140 --> 00:40:04,820
all the continents of the Earth
that we know today
were grouped together

473
00:40:04,820 --> 00:40:07,660
to form one huge super-continent,

474
00:40:07,660 --> 00:40:13,700
and that over time this broke up
and the pieces drifted apart.

475
00:40:13,700 --> 00:40:17,300
That would have provided an answer.

476
00:40:17,300 --> 00:40:22,060
But when I asked
the professor of geology here
who was lecturing to us

477
00:40:22,060 --> 00:40:24,860
why he didn't tell us
about that in his lectures,

478
00:40:24,860 --> 00:40:29,020
he replied,
rather loftily I must say,

479
00:40:29,020 --> 00:40:36,220
"When you can demonstrate to me that
there is a force on Earth that can
move the continents by a millimetre,

480
00:40:36,220 --> 00:40:42,980
"I will consider it,
But until then, the idea is
sheer moonshine, dear boy!"

481
00:40:44,620 --> 00:40:47,420
But then, in the 1960s,

482
00:40:47,420 --> 00:40:51,780
it became possible to map
the sea floor in detail,

483
00:40:51,780 --> 00:40:55,620
and it was discovered not only
that the continents have shifted

484
00:40:55,620 --> 00:40:59,500
in just the way that the
German geologist had suggested,

485
00:40:59,500 --> 00:41:01,780
but that they were still moving.

486
00:41:03,620 --> 00:41:07,100
New rock wells up from deep below
the Earth's crust,

487
00:41:07,100 --> 00:41:13,700
and flows away on either side
of the mid-ocean ridges,
carrying the continents with it.

488
00:41:13,700 --> 00:41:17,580
Amphibians had originally evolved
on this super-continent

489
00:41:17,580 --> 00:41:22,980
and had then travelled
on each of its various fragments
as they drifted apart.

490
00:41:22,980 --> 00:41:24,460
Problem solved!

491
00:41:29,220 --> 00:41:32,220
Perhaps the biggest problem of all
for most people

492
00:41:32,220 --> 00:41:37,060
was the argument
put forward for the existence of God

493
00:41:37,060 --> 00:41:42,940
at the beginning of the 19th century
by an Anglican clergyman called
William Paley.

494
00:41:42,940 --> 00:41:50,100
He said, supposing you were walking
in the countryside and you picked up
something like this.

495
00:41:50,100 --> 00:41:52,820
You would know from looking at it

496
00:41:52,820 --> 00:41:57,580
that it had been designed
to tell the time.

497
00:41:59,180 --> 00:42:02,660
There must, therefore,
be a designer.

498
00:42:02,660 --> 00:42:08,300
And the same argument would apply if
you looked at one of the intricate
structures found in nature,

499
00:42:08,300 --> 00:42:10,780
such as the human eye.

500
00:42:10,780 --> 00:42:15,660
And the only designer
of the human eye could be God.

501
00:42:15,660 --> 00:42:20,860
Anti-evolutionists maintain
that the eye would only work

502
00:42:20,860 --> 00:42:24,580
if it was complete
in all its details.

503
00:42:24,580 --> 00:42:29,060
Darwin, on the other hand,
argued that the eye had developed,

504
00:42:29,060 --> 00:42:33,420
becoming increasingly complex
over a long period of time.

505
00:42:33,420 --> 00:42:37,500
That would only work
if each stage of development

506
00:42:37,500 --> 00:42:40,260
was an improvement
on the previous one,

507
00:42:40,260 --> 00:42:47,100
and today we know enough
about the animal kingdom to know
that that is indeed the case.

508
00:42:48,180 --> 00:42:53,220
Some very simple animals
have nothing more than
light-sensitive spots

509
00:42:53,220 --> 00:42:57,380
that enable them to tell the
difference between light and dark.

510
00:42:57,380 --> 00:43:02,220
But if a patch of such spots formed
even the shallowest of pits,

511
00:43:02,220 --> 00:43:04,900
one edge of the pit
would throw a shadow,

512
00:43:04,900 --> 00:43:08,340
and so reveal
the direction of light.

513
00:43:08,340 --> 00:43:14,740
If the pit got deeper and
started to close, then light
would form a blurred image.

514
00:43:14,740 --> 00:43:19,300
Mucus secreted by the cells
would bend the light and focus it.

515
00:43:19,300 --> 00:43:23,100
If this mucus hardened,
it would form a proper lens

516
00:43:23,100 --> 00:43:26,540
and transmit
a brighter and clearer image.

517
00:43:26,540 --> 00:43:30,300
All these different
fully-functional stages

518
00:43:30,300 --> 00:43:36,140
at different levels of complexity
are found in living animals today.

519
00:43:36,140 --> 00:43:41,740
This single-celled creature has
one of those light-sensitive spots.

520
00:43:41,740 --> 00:43:45,420
Flatworms have a small pit
containing light spots,

521
00:43:45,420 --> 00:43:50,060
so they can detect
the shadow of a predator.

522
00:43:50,060 --> 00:43:55,540
A snail's blurry vision
is good enough to enable it
to find its way to food.

523
00:43:55,540 --> 00:44:01,460
And the octopus has an eye
with a proper lens and can
see as much detail as we can.

524
00:44:06,380 --> 00:44:12,140
So the structure of the human eye
does not demand the assistance
of a supernatural designer.

525
00:44:12,140 --> 00:44:14,500
It can have evolved gradually,

526
00:44:14,500 --> 00:44:19,340
with each stage bringing
a real advantage,
as Darwin's theory demands.

527
00:44:25,020 --> 00:44:26,820
Natural selection, of course,

528
00:44:26,820 --> 00:44:32,460
requires that an animal's
characteristics are handed from
one generation to the next.

529
00:44:32,460 --> 00:44:35,980
It's obvious that children
resemble their parents.

530
00:44:35,980 --> 00:44:38,460
Anyone knows that.

531
00:44:38,460 --> 00:44:42,900
But when you come to think of it,
how does that come about?

532
00:44:42,900 --> 00:44:46,420
In Darwin's time,
nobody had the faintest idea

533
00:44:46,420 --> 00:44:51,260
about the mechanism or the rules
that governed that process,

534
00:44:51,260 --> 00:44:57,140
except perhaps for one man
who was working in the city of Brno,

535
00:44:57,140 --> 00:45:03,820
in what is now the Czech Republic,
at exactly the same time that Darwin
was writing his book in Kent.

536
00:45:03,820 --> 00:45:06,940
That man's name was Gregor Mendel.

537
00:45:08,500 --> 00:45:11,340
He discovered the
laws of inheritance

538
00:45:11,340 --> 00:45:13,780
by breeding thousands of pea plants

539
00:45:13,780 --> 00:45:18,660
and observing how they changed
from one generation to the next.

540
00:45:18,660 --> 00:45:21,700
He found that
while many characteristics

541
00:45:21,700 --> 00:45:24,820
were passed down directly
from one generation to another,

542
00:45:24,820 --> 00:45:30,060
others could actually skip a
generation. How could that happen?

543
00:45:30,060 --> 00:45:36,140
Mendel explained this by suggesting
that each plant, each organism,

544
00:45:36,140 --> 00:45:40,540
contained within it
factors which were responsible

545
00:45:40,540 --> 00:45:45,460
for creating
those particular characteristics.

546
00:45:45,460 --> 00:45:48,260
Today, we call those things genes,

547
00:45:48,260 --> 00:45:54,340
but nobody had any idea how they
worked until 100 years after
Mendel's time.

548
00:45:54,340 --> 00:45:59,220
And then the answer was discovered
in Cambridge.

549
00:46:02,300 --> 00:46:08,420
In 1953, here in the Cavendish
laboratories, two young researchers,

550
00:46:08,420 --> 00:46:13,940
Francis Crick and James Watson,
were building models like this.

551
00:46:13,940 --> 00:46:19,500
It was their way of thinking about
and investigating the structure

552
00:46:19,500 --> 00:46:26,620
of a complex molecule that's found
in the genes of all animals - DNA.

553
00:46:26,620 --> 00:46:31,220
The crucial bit are these chains,

554
00:46:31,220 --> 00:46:33,060
which encircle the rod -

555
00:46:35,820 --> 00:46:39,620
and here is a second - and entwine.

556
00:46:39,620 --> 00:46:42,740
This is a double helix.

557
00:46:44,980 --> 00:46:49,940
The workings of the DNA molecule
are now understood in such detail

558
00:46:49,940 --> 00:46:53,780
that we can demonstrate
something that is truly astounding.

559
00:46:54,940 --> 00:46:58,780
A gene taken from one animal
can function in another.

560
00:46:59,900 --> 00:47:03,900
The gene that causes a jellyfish
to be luminous, for example,

561
00:47:03,900 --> 00:47:08,740
transplanted into a mouse,
will make that mouse luminous.

562
00:47:15,860 --> 00:47:21,060
The genetic code can
also reveal relationships.

563
00:47:21,060 --> 00:47:24,740
Even our law courts accept
that DNA fingerprinting

564
00:47:24,740 --> 00:47:28,820
can establish whether a man is
the father of a particular child.

565
00:47:30,900 --> 00:47:35,980
And it can also reveal
whether one kind of animal
is related to another.

566
00:47:41,860 --> 00:47:44,820
It proves, for example,
that kangaroos -

567
00:47:44,820 --> 00:47:48,980
ground-living animals
that run with great leaps -

568
00:47:48,980 --> 00:47:54,220
are closely related to koalas
that have taken to climbing trees.

569
00:47:54,220 --> 00:47:59,500
That insect-eating shrews
have cousins that took to the air

570
00:47:59,500 --> 00:48:01,780
in search of insects - bats.

571
00:48:01,780 --> 00:48:06,460
And that one branch of the
elephant family,
way back in geological history,

572
00:48:06,460 --> 00:48:11,180
took to the water
and became sea cows.

573
00:48:11,180 --> 00:48:18,140
So, 150 years after the publication
of Darwin's revolutionary book,

574
00:48:18,140 --> 00:48:22,820
modern genetics has confirmed
its fundamental truth -

575
00:48:22,820 --> 00:48:25,820
all life is related.

576
00:48:25,820 --> 00:48:29,180
And it enables us
to construct with confidence

577
00:48:29,180 --> 00:48:35,420
the complex tree
that represents the history of life.

578
00:48:35,420 --> 00:48:37,820
It began in the sea,

579
00:48:37,820 --> 00:48:41,220
some 3,000 million years ago.

580
00:48:41,220 --> 00:48:45,460
Complex chemical molecules
began to clump together

581
00:48:45,460 --> 00:48:49,860
to form microscopic blobs - cells.

582
00:48:51,420 --> 00:48:55,620
These were the seeds from
which the tree of life developed.

583
00:48:55,620 --> 00:49:00,180
They were able to split, replicating
themselves as bacteria do.

584
00:49:00,180 --> 00:49:04,340
And as time passed, they
diversified into different groups.

585
00:49:05,420 --> 00:49:09,820
Some remained attached to one
another, so that they formed chains.

586
00:49:09,820 --> 00:49:13,180
We know them today as algae.

587
00:49:13,180 --> 00:49:17,260
Others formed hollow balls
which collapsed upon themselves,

588
00:49:17,260 --> 00:49:21,180
creating a body
with an internal cavity.

589
00:49:21,180 --> 00:49:24,460
They were the first
multi-celled organisms -

590
00:49:24,460 --> 00:49:28,780
sponges are their direct
descendents.

591
00:49:28,780 --> 00:49:35,020
As more variations appeared,
the tree of life grew
and became more diverse.

592
00:49:35,020 --> 00:49:40,660
Some organisms became more mobile
and developed a mouth
that opened into a gut.

593
00:49:43,540 --> 00:49:48,540
Others had bodies
stiffened by an internal rod.

594
00:49:48,540 --> 00:49:52,860
They understandably developed
sense organs around their front end.

595
00:49:54,420 --> 00:49:58,020
A related group had bodies
that were divided into segments

596
00:49:58,020 --> 00:50:03,620
with little projections on
either side that helped them
to move around on the sea floor.

597
00:50:03,620 --> 00:50:07,700
Some of these segmented creatures
developed hard protective skins

598
00:50:07,700 --> 00:50:10,900
which gave their bodies
some rigidity.

599
00:50:10,900 --> 00:50:15,420
So now the seas were filled
with a great variety of animals.

600
00:50:16,980 --> 00:50:20,260
And then,
around 450 million years ago,

601
00:50:20,260 --> 00:50:26,140
some of these armoured creatures
crawled up, out of the water and
ventured onto land.

602
00:50:28,860 --> 00:50:33,460
And here, the tree of life
branched into a multitude
of different species

603
00:50:33,460 --> 00:50:37,340
that exploited this new
environment in all kinds of ways.

604
00:50:39,460 --> 00:50:43,660
One group of them developed
elongated flaps on their backs,

605
00:50:43,660 --> 00:50:48,500
which, over many generations,
eventually developed into wings.

606
00:50:48,500 --> 00:50:51,980
The insects had arrived.

607
00:50:51,980 --> 00:50:56,980
Life moved into the air
and diversified into myriad forms.

608
00:51:00,300 --> 00:51:01,940
Meanwhile, back in the seas,

609
00:51:01,940 --> 00:51:07,900
those creatures with the stiffening
rod in their bodies had strengthened
it by encasing it in bone.

610
00:51:09,620 --> 00:51:15,980
A skull developed, with a hinged jaw
that could grab and hold on to prey.

611
00:51:15,980 --> 00:51:18,620
They grew bigger,
and developed fins

612
00:51:18,620 --> 00:51:22,860
equipped with muscles that enabled
them to swim with speed and power.

613
00:51:24,140 --> 00:51:28,700
So fish now dominated
the waters of the world.

614
00:51:28,700 --> 00:51:34,220
One group of them developed
the ability to gulp air
from the water surface.

615
00:51:36,820 --> 00:51:42,980
Their fleshy fins became
weight-supporting legs
and 375 million years ago,

616
00:51:42,980 --> 00:51:49,100
a few of these backboned creatures
followed the insects onto the land.

617
00:51:49,100 --> 00:51:54,980
They were amphibians with wet skins
and they had to return to
water to lay their eggs,

618
00:51:54,980 --> 00:51:59,140
but some of their descendents
evolved dry, scaly skins

619
00:51:59,140 --> 00:52:04,260
and broke their link with water by
laying eggs with watertight shells.

620
00:52:06,180 --> 00:52:13,340
These creatures, the reptiles, were
the ancestors of today's tortoises,
snakes, lizards and crocodiles.

621
00:52:13,340 --> 00:52:20,340
And of course they included the
group that back then came to
dominate the land - the dinosaurs.

622
00:52:22,980 --> 00:52:27,500
But 65 million years ago,
a great disaster overtook the Earth.

623
00:52:32,820 --> 00:52:36,620
Whatever its cause,
a great proportion of
animals were exterminated.

624
00:52:36,620 --> 00:52:40,820
All the dinosaurs disappeared,
except for one branch

625
00:52:40,820 --> 00:52:43,740
whose scales had
become modified into feathers.

626
00:52:45,340 --> 00:52:47,220
They were the birds.

627
00:52:47,220 --> 00:52:49,660
While they spread through the skies,

628
00:52:49,660 --> 00:52:55,940
a small, seemingly insignificant
group of survivors began to increase
in numbers on the ground beneath.

629
00:52:57,740 --> 00:53:00,580
These creatures differed
from their competitors

630
00:53:00,580 --> 00:53:04,540
in that their bodies were warm
and insulated with coats of fur -

631
00:53:04,540 --> 00:53:07,420
they were the first mammals.

632
00:53:07,420 --> 00:53:13,660
With much of the land left
vacant after the great catastrophe,
they now had their chance.

633
00:53:13,660 --> 00:53:18,020
Their warm, insulated bodies enabled
them to be active at all times,

634
00:53:18,020 --> 00:53:21,300
at night as well as during the day.

635
00:53:21,300 --> 00:53:26,340
And in all places,
from the Arctic to the Tropics.

636
00:53:26,340 --> 00:53:30,020
In water as well as on land.

637
00:53:30,020 --> 00:53:33,980
On grassy plains and up
in the trees.

638
00:54:09,340 --> 00:54:11,020
HE CHUCKLES

639
00:54:14,540 --> 00:54:20,420
There can be no doubt
about our close relationship
to these chimpanzees.

640
00:54:20,420 --> 00:54:22,820
Our bodies are so similar,

641
00:54:22,820 --> 00:54:26,860
the proportions of our limbs
or our faces may differ,

642
00:54:26,860 --> 00:54:29,260
but otherwise
we are very, very similar.

643
00:54:30,780 --> 00:54:34,620
The arrangement of our internal
organs, the chemistry of our blood,

644
00:54:34,620 --> 00:54:39,660
the way our bodies work...
All these are almost identical.

645
00:54:39,660 --> 00:54:43,140
And DNA confirms that.

646
00:54:43,140 --> 00:54:47,700
Indeed, we are as closely related
to chimpanzees

647
00:54:47,700 --> 00:54:52,900
and the rest of the apes and monkeys
as, say, lions are to tigers

648
00:54:52,900 --> 00:54:54,900
and to the rest of the cat family.

649
00:55:18,700 --> 00:55:23,980
Suddenly, an image from our remote
past comes vividly to light -

650
00:55:23,980 --> 00:55:26,180
the time when our distant ancestors,

651
00:55:26,180 --> 00:55:29,460
in order to keep up with
the changing environment,

652
00:55:29,460 --> 00:55:33,060
had to wade and keep their heads
above water

653
00:55:33,060 --> 00:55:35,340
in order to find food.

654
00:55:35,340 --> 00:55:39,380
That crucial moment
when our far distant ancestors

655
00:55:39,380 --> 00:55:45,580
took a step away from being apes
and a step towards humanity.

656
00:55:59,540 --> 00:56:05,340
The Natural History Museum is one
of the most important museums
of its kind in the world.

657
00:56:05,340 --> 00:56:10,260
Richard Owen brought it into
existence, but over a century later,

658
00:56:10,260 --> 00:56:14,980
discoveries from many branches of
science have shown that his belief

659
00:56:14,980 --> 00:56:20,580
that species can never change,
but always remain exactly the same
was mistaken.

660
00:56:40,660 --> 00:56:46,820
It was Charles Darwin's
profound insights
that have proved to be true.

661
00:56:46,820 --> 00:56:50,260
And now, to mark the 200th
anniversary of his birth,

662
00:56:50,260 --> 00:56:54,420
his statue is being taken
from its out-of-the-way location

663
00:56:54,420 --> 00:56:59,220
to be placed centre stage
in the main hall.

664
00:57:14,900 --> 00:57:20,180
Darwin's great insight
revolutionised the way in
which we see the world.

665
00:57:20,180 --> 00:57:23,620
We now understand why there
are so many different species,

666
00:57:23,620 --> 00:57:28,100
why they are distributed in the
way they are around the world.

667
00:57:28,100 --> 00:57:32,980
And why their bodies and our bodies
are shaped in the way that they are.

668
00:57:32,980 --> 00:57:36,420
Because we understand that
bacteria evolve,

669
00:57:36,420 --> 00:57:40,500
we can devise methods of dealing
with the diseases they cause.

670
00:57:40,500 --> 00:57:44,140
And because we can disentangle
the complex relationships

671
00:57:44,140 --> 00:57:47,260
between animals and plants
in a natural community,

672
00:57:47,260 --> 00:57:52,820
we can foresee some of the
consequences when we start
to interfere with those communities.

673
00:57:54,340 --> 00:58:00,220
But above all, Darwin has shown us
that we are not apart
from the natural world.

674
00:58:00,220 --> 00:58:04,220
We do not have dominion over it.

675
00:58:04,220 --> 00:58:08,100
We are subject
to its laws and processes,

676
00:58:08,100 --> 00:58:14,340
as are all other animals on Earth -
to which indeed we are related.

677
00:58:15,820 --> 00:58:17,820
HE CHUCKLES

678
00:58:42,860 --> 00:58:45,220
For your Tree Of Life poster,

679
00:58:45,220 --> 00:58:47,860
and to find out more
about Charles Darwin

680
00:58:47,860 --> 00:58:54,780
and Open University
programmes on the BBC, call -

681
00:58:54,780 --> 00:58:59,060
Or go to -

682
00:59:01,900 --> 00:59:04,940
Subtitles by Red Bee Media Ltd

683
00:59:04,940 --> 00:59:07,980
Email subtitling@bbc.co.uk