Darwin's Tree of Life

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0:00:02 > 0:00:06I've been making natural history films for over 60 years.

0:00:06 > 0:00:10And in the process, I've been to some very interesting places.

0:00:10 > 0:00:14But every now and again I've been allowed to make a film

0:00:14 > 0:00:18about my other enthusiasms, about the history of exploration,

0:00:18 > 0:00:22about tribal objects, or the life of a great scientist.

0:00:22 > 0:00:25You could call them my passion projects.

0:00:56 > 0:00:59Well, the year 2009 was

0:00:59 > 0:01:02the bicentenary of Charles Darwin's birth.

0:01:03 > 0:01:05And I think any naturalist,

0:01:05 > 0:01:09any biologist will agree that his theory,

0:01:09 > 0:01:11and his thought,

0:01:11 > 0:01:17is the most important step forward in zoological science.

0:01:22 > 0:01:26Before this book, the natural world and natural history,

0:01:26 > 0:01:28and zoology, could be regarded as

0:01:28 > 0:01:30a glorified form of stamp collecting.

0:01:30 > 0:01:33You've got one animal, and then you've got another animal,

0:01:33 > 0:01:35and you said it was slightly different from this animal.

0:01:35 > 0:01:39But that was all. But this book made sense of those differences.

0:01:41 > 0:01:44You know, if you look in the garden and you see a coal tit,

0:01:44 > 0:01:47and a great tit, and a blue tit,

0:01:47 > 0:01:51it just makes common sense to think that they are related.

0:01:51 > 0:01:54And what Darwin showed you is that, of course they're related.

0:01:54 > 0:01:57They evolved one from the other.

0:01:57 > 0:01:59And not only that but actually,

0:01:59 > 0:02:02birds as a whole evolved from reptiles,

0:02:02 > 0:02:06and reptiles as a whole evolved from amphibians,

0:02:06 > 0:02:09and amphibians as a whole developed from fish.

0:02:10 > 0:02:12So it...

0:02:12 > 0:02:17But he explains the mechanisms in which this happens in this book.

0:02:17 > 0:02:21Which is one of the great books of the world.

0:02:21 > 0:02:24So it was obvious I had to make a film about it.

0:02:26 > 0:02:30Our earth is the only known planet that sustains life -

0:02:30 > 0:02:32and it does so in abundance.

0:02:46 > 0:02:51I have been fortunate enough, over the years, to travel to some of the

0:02:51 > 0:02:56most extraordinary and remote places on earth to find and film animals.

0:02:56 > 0:03:00This is the biggest flower in the world.

0:03:00 > 0:03:02The Blue Whale!

0:03:02 > 0:03:06It's the biggest creature that exists on the planet.

0:03:08 > 0:03:12The sheer number and variety of animals and plants is astonishing.

0:03:13 > 0:03:17Estimates of the number of different species vary from six million

0:03:17 > 0:03:19to 100 million.

0:03:20 > 0:03:22Nobody knows exactly how many different

0:03:22 > 0:03:24kinds of animals there are here.

0:03:24 > 0:03:26Wherever you look there's life.

0:03:26 > 0:03:31There are often a multitude of variations on a single pattern.

0:03:31 > 0:03:36Nearly 200 different kinds of monkeys, for example.

0:03:37 > 0:03:40And 315 hummingbirds.

0:03:42 > 0:03:44Nearly a thousand bats.

0:03:51 > 0:03:57And beetles - at least 350,000 species of them.

0:03:57 > 0:03:58Not to mention,

0:03:58 > 0:04:02a quarter of a million different kinds of flowering plants.

0:04:10 > 0:04:12The variety is astounding.

0:04:20 > 0:04:22Even in this one small English woodland,

0:04:22 > 0:04:26you might see four or five different kinds of finches.

0:04:32 > 0:04:36Why should there be such a dazzling variety?

0:04:36 > 0:04:40And how can we make sense of such a huge range of living organisms?

0:04:43 > 0:04:48200 years ago, a man was born who was to explain

0:04:48 > 0:04:51this astonishing diversity of life.

0:04:51 > 0:04:55In doing so, he revolutionised the way in which we see the world

0:04:55 > 0:04:58and our place in it.

0:04:58 > 0:05:01His name was Charles Darwin.

0:05:22 > 0:05:24This book - the Holy Bible -

0:05:24 > 0:05:29explains how this wonderful diversity came about.

0:05:29 > 0:05:33On the third day after the creation of the world,

0:05:33 > 0:05:36God created plants.

0:05:36 > 0:05:40On the fifth day, fish and birds.

0:05:40 > 0:05:46And then on the sixth day - mammals, and finally man.

0:05:46 > 0:05:48And when God had finished,

0:05:48 > 0:05:51he said to Adam and Eve,

0:05:51 > 0:05:57"Be fruitful and multiply and replenish the earth and subdue it,

0:05:57 > 0:05:59"and have dominion over the fish of the sea

0:05:59 > 0:06:01"and over the fowl of the air,

0:06:01 > 0:06:07"and over every living thing that moveth upon the earth."

0:06:07 > 0:06:10That made it clear that, according to the Bible,

0:06:10 > 0:06:14humanity could exploit the natural world, as they wished.

0:06:19 > 0:06:22This view of mankind's superiority

0:06:22 > 0:06:27still stood when, in 1831, a British surveying ship, The Beagle,

0:06:27 > 0:06:30set off on a voyage around the world.

0:06:30 > 0:06:33On board, as a companion to the captain,

0:06:33 > 0:06:36was the 22-year-old Charles Darwin.

0:06:38 > 0:06:42They crossed the Atlantic and made landfall on the coast of Brazil.

0:06:45 > 0:06:48There the sheer abundance of tropical nature

0:06:48 > 0:06:50astonishes the new-comer,

0:06:50 > 0:06:54as I discovered when I retraced Darwin's steps 30 years ago,

0:06:54 > 0:06:58for a television series about the diversity of nature.

0:06:59 > 0:07:04Darwin, as a boy, had been a fanatical collector of insects,

0:07:04 > 0:07:08and here he was enthralled, almost to the point of ecstasy.

0:07:08 > 0:07:09In one day,

0:07:09 > 0:07:11in a small area,

0:07:11 > 0:07:15he discovered 69 different species of beetle.

0:07:16 > 0:07:18As he wrote in his journal,

0:07:18 > 0:07:20it's enough to disturb

0:07:20 > 0:07:23the composure of the entomologist's mind,

0:07:23 > 0:07:27to contemplate the future dimension of a complete catalogue.

0:07:30 > 0:07:33They went south, rounded Cape Horn

0:07:33 > 0:07:34and so reached the Pacific.

0:07:38 > 0:07:42And then, in September 1835,

0:07:42 > 0:07:45after they had been away for almost four years,

0:07:45 > 0:07:48they landed on the little known islands of the Galapagos.

0:07:50 > 0:07:53Here they found creatures that existed nowhere else in the world.

0:07:53 > 0:07:58Cormorants that had lost the power of flight.

0:07:58 > 0:08:01Lizards that swam out through the surf to

0:08:01 > 0:08:03graze on the bottom of the sea.

0:08:03 > 0:08:07Darwin, who had studied Botany and Geology at Cambridge University,

0:08:07 > 0:08:12collected specimens of the animals and plants.

0:08:12 > 0:08:15The British resident in the Galapagos claimed that he

0:08:15 > 0:08:18knew from the shape of a giant tortoise's shell,

0:08:18 > 0:08:20which island it had come from.

0:08:20 > 0:08:22If it had a rounded front,

0:08:22 > 0:08:28it came from a well watered island where it fed on lush ground plants.

0:08:28 > 0:08:32Whereas one from a drier island had a peak at the front which

0:08:32 > 0:08:35enabled it to reach up to higher vegetation.

0:08:39 > 0:08:44Were these tortoises, each on their separate islands, different species?

0:08:45 > 0:08:49And if so, was each one a separate act of Divine creation?

0:08:53 > 0:08:56The differences that Darwin had noticed amongst

0:08:56 > 0:09:00these Galapagos animals were, of course, all tiny,

0:09:00 > 0:09:03but if they could develop, wasn't it possible that over

0:09:03 > 0:09:07the thousands or millions of years, a whole series of such differences

0:09:07 > 0:09:11might add up to one revolutionary change?

0:09:14 > 0:09:15On his voyage home,

0:09:15 > 0:09:19Darwin had time to ponder on these things.

0:09:19 > 0:09:23Could it be that species were not fixed for all time,

0:09:23 > 0:09:25but could in fact slowly change?

0:09:32 > 0:09:36On his return, he sorted out his specimens and sent them

0:09:36 > 0:09:41off to relevant experts so that each could be identified and classified.

0:09:46 > 0:09:52Most of the mammal bones and fossils he sent to Richard Owen.

0:09:52 > 0:09:55Owen was one of the most brilliant zoologists of his time.

0:09:55 > 0:09:58He was the first to recognise dinosaurs -

0:09:58 > 0:10:01and indeed had invented their very name.

0:10:01 > 0:10:03And he would later become the

0:10:03 > 0:10:07creator and first director of the Natural History Museum in London.

0:10:12 > 0:10:16Many of the specimens that Darwin collected are still preserved,

0:10:16 > 0:10:20and treasured - here, among the 70 million other specimens

0:10:20 > 0:10:23housed in the museum that Owen founded.

0:10:28 > 0:10:31And here is one of them.

0:10:33 > 0:10:36It's obviously the lower jaw of some great animal,

0:10:36 > 0:10:39and when Darwin discovered it, it had bits of skin

0:10:39 > 0:10:42and hair attached to it, so that at first it was thought to be

0:10:42 > 0:10:46the remains of some unknown living species.

0:10:46 > 0:10:48But now we know that it is a species that was

0:10:48 > 0:10:53extinct for some 10,000 years - a giant ground sloth.

0:10:53 > 0:10:59Owen examined it in great detail and eventually described it and

0:10:59 > 0:11:05gave it the name of Mylodon Darwinii in honour of its discoverer.

0:11:05 > 0:11:09But that mutual respect between two great men of science

0:11:09 > 0:11:11was not to last.

0:11:16 > 0:11:19Soon after his return from his voyage,

0:11:19 > 0:11:23Darwin made his home here in Down House in Kent.

0:11:23 > 0:11:26Here he wrote an account of his travels

0:11:26 > 0:11:30and worked on detailed scientific treatises about corals

0:11:30 > 0:11:34and barnacles, and the geology and fossils of South America.

0:11:37 > 0:11:40But he also pondered deeply on what he had

0:11:40 > 0:11:42seen in the Galapagos and elsewhere.

0:11:42 > 0:11:45Maybe species were not fixed.

0:12:02 > 0:12:06Every day, he took a walk in this small spinney that he

0:12:06 > 0:12:08had planted at the end of his garden.

0:12:10 > 0:12:13And it was here that he came to ponder

0:12:13 > 0:12:15on the problems of natural history,

0:12:15 > 0:12:18including that mystery of mysteries -

0:12:18 > 0:12:22how could one species turn into another?

0:12:24 > 0:12:27He noted that most, if not all, animals produce

0:12:27 > 0:12:31many more young than live to breed themselves.

0:12:33 > 0:12:36This female blue tit, for example,

0:12:36 > 0:12:40may well lay a dozen eggs a year - perhaps 50 or so in her lifetime.

0:12:40 > 0:12:43Yet only two of her chicks need to survive

0:12:43 > 0:12:45and breed themselves,

0:12:45 > 0:12:47to maintain the numbers of the blue tit population.

0:12:47 > 0:12:51Those survivors, of course, are likely to be the healthiest

0:12:51 > 0:12:54and best suited to their particular environment.

0:12:55 > 0:12:57Their characteristics are then inherited.

0:12:57 > 0:13:01So, perhaps over many generations - and particularly

0:13:01 > 0:13:05if there are environmental changes - species may well change.

0:13:06 > 0:13:12Only the fittest survive - and that was the key.

0:13:12 > 0:13:16He called the process "natural selection".

0:13:24 > 0:13:27That would explain the differences that he had

0:13:27 > 0:13:32noted in the finches that he had brought back from the Galapagos.

0:13:32 > 0:13:36They were very similar except for their beaks.

0:13:36 > 0:13:41This one has a very thin, delicate beak which it uses to catch insects.

0:13:42 > 0:13:44This one, on the other hand,

0:13:44 > 0:13:48which came from an environment where there were a lot of nuts,

0:13:48 > 0:13:52has a big heavy beak which enables it to crack them.

0:13:53 > 0:13:57maybe, over the vastness of geological time,

0:13:57 > 0:14:01and particularly if species were invading new environments,

0:14:01 > 0:14:06those changes would amount to very radical changes indeed.

0:14:17 > 0:14:22Darwin drew a sketch in one of his notebooks to illustrate his idea.

0:14:23 > 0:14:28Showing how a single ancestral species might give rise to several

0:14:28 > 0:14:33different ones and then wrote above it a tentative,

0:14:33 > 0:14:35"I think".

0:14:43 > 0:14:46Now he had to prove his theory -

0:14:46 > 0:14:51and he spent years gathering abundant and convincing evidence.

0:14:51 > 0:14:54He was an extraordinary letter writer.

0:14:54 > 0:14:58He wrote as many as a dozen letters a day to scientists

0:14:58 > 0:15:00and naturalists all over the world.

0:15:12 > 0:15:13He also realised,

0:15:13 > 0:15:17that when people had first started domesticating animals,

0:15:17 > 0:15:21they had been doing experiments for him - for centuries.

0:15:26 > 0:15:29All domestic dogs are descended from a single

0:15:29 > 0:15:32ancestral species - the wolf.

0:15:32 > 0:15:34Dog breeders select those pups

0:15:34 > 0:15:38that have the characteristics that happen to please them.

0:15:38 > 0:15:40Nature, of course, selects those young animals

0:15:40 > 0:15:43that are best suited to a particular environment,

0:15:43 > 0:15:46but the process is essentially the same

0:15:46 > 0:15:50and in both cases, it has produced astonishing variety.

0:15:58 > 0:16:00In effect,

0:16:00 > 0:16:04many of these different breeds could be considered different species

0:16:04 > 0:16:07because they do not - indeed they cannot inter-breed.

0:16:07 > 0:16:09For purely mechanical reasons,

0:16:09 > 0:16:13there's no way in which a Pekinese can mate with a Great Dane.

0:16:20 > 0:16:21Of course it's true that

0:16:21 > 0:16:24if you used artificial insemination you could get

0:16:24 > 0:16:27crosses between almost any of these breeds,

0:16:27 > 0:16:30but that's because human beings have been

0:16:30 > 0:16:33selecting between dogs for only a few centuries.

0:16:33 > 0:16:39Nature has been selecting between animals for millions of years,

0:16:39 > 0:16:42tens of millions, even hundreds of millions of years.

0:16:42 > 0:16:46So what might have started out as we would consider to be breeds

0:16:46 > 0:16:50have now become so different, they are species.

0:17:11 > 0:17:14Darwin, sitting in Down House,

0:17:14 > 0:17:17wrote to pigeon fanciers and rabbit breeders,

0:17:17 > 0:17:19asking all kinds of detailed questions

0:17:19 > 0:17:21about their methods and results.

0:17:21 > 0:17:26He himself, being a country gentleman and running an estate,

0:17:26 > 0:17:29knew about breeding horses and sheep and cattle.

0:17:29 > 0:17:32And he also conducted careful experiments with

0:17:32 > 0:17:34plants in his greenhouse.

0:17:39 > 0:17:42But Darwin knew that the idea that species could

0:17:42 > 0:17:47appear without divine intervention would appal society in general,

0:17:47 > 0:17:51and it was also contrary to the beliefs of his wife Emma,

0:17:51 > 0:17:52who was a devout Christian.

0:17:54 > 0:17:55Perhaps for that reason,

0:17:55 > 0:17:58he was keen to keep the focus of his work scientific.

0:18:01 > 0:18:03He made a point of not being drawn in public

0:18:03 > 0:18:05about his religious beliefs,

0:18:05 > 0:18:07but in the latter part of his life

0:18:07 > 0:18:09he withdrew from attending church.

0:18:11 > 0:18:14On Sundays he would escort Emma and the children here,

0:18:14 > 0:18:16to the parish church in Downe,

0:18:16 > 0:18:19but while they went into the service,

0:18:19 > 0:18:23he remained outside and went for a walk in the country lanes.

0:18:31 > 0:18:33Perhaps because he feared

0:18:33 > 0:18:36that his theory would cause outrage in some quarters,

0:18:36 > 0:18:41he delayed publishing it year after year after year.

0:18:41 > 0:18:44But he wrote a long abstract of it

0:18:44 > 0:18:49and then on July the 5th 1844, he wrote this letter to his wife.

0:18:49 > 0:18:51"My dear Emma.

0:18:51 > 0:18:56"I have just finished this sketch of my species theory -

0:18:56 > 0:18:58"some sketch - it was 240 pages long.

0:18:59 > 0:19:03"I therefore write this in case of my sudden death that you will

0:19:03 > 0:19:07"devote 400 pounds to its publication."

0:19:07 > 0:19:11He then goes on to list his various naturalist friends

0:19:11 > 0:19:14who would be asked to edit it and check it,

0:19:14 > 0:19:17and he ends the letter charmingly,

0:19:17 > 0:19:23"My dear wife, - yours, affectionately, CR Darwin."

0:19:32 > 0:19:35He continued to accumulate evidence

0:19:35 > 0:19:38and refine his theory for the next 14 years.

0:19:43 > 0:19:46But then his hand was forced.

0:19:46 > 0:19:52In June 1858, 22 years after he got back from the Galapagos,

0:19:52 > 0:19:55here in his study in Down, he received

0:19:55 > 0:20:00a package from a naturalist who was working in what is now Indonesia.

0:20:01 > 0:20:05His name was Alfred Russell Wallace.

0:20:08 > 0:20:12He had been corresponding with Darwin for some years.

0:20:12 > 0:20:15But this package was different.

0:20:15 > 0:20:18It contained an essay that set out exactly the same

0:20:18 > 0:20:22idea as Darwin's - of evolution by natural selection.

0:20:25 > 0:20:29The idea had come to Wallace as he lay in his hut,

0:20:29 > 0:20:31semi-delirious in a malarial fever.

0:20:32 > 0:20:37But although his idea of natural selection was the same as Darwin's,

0:20:37 > 0:20:38he had not spent 20 years gathering

0:20:38 > 0:20:42the mountain of evidence to support it, as Darwin had done.

0:20:44 > 0:20:47But whose idea was it?

0:20:47 > 0:20:50In the end, the senior members of the Linnean Society

0:20:50 > 0:20:53decided that the fairest thing was for a brief

0:20:53 > 0:20:56outline of the theory from each of them to be read out,

0:20:56 > 0:20:57one after the other,

0:20:57 > 0:21:01at a meeting of the Society, here in Burlington House, in London.

0:21:03 > 0:21:06The Linnean, then as now, was the place where scientists

0:21:06 > 0:21:10studying the natural world held regular meetings,

0:21:10 > 0:21:14to present and discuss papers about their observations and thoughts.

0:21:16 > 0:21:20The one held on July 1st, 1858

0:21:20 > 0:21:24was attended by only about 30 people.

0:21:24 > 0:21:27Neither of the authors were present.

0:21:27 > 0:21:31Wallace was 10,000 miles away in the East Indies,

0:21:31 > 0:21:35and Darwin was ill and devastated by the death, a few days earlier,

0:21:35 > 0:21:41of his infant son - so he was still at his home in Kent.

0:21:41 > 0:21:46As a consequence, the two papers had to be read by the secretary and,

0:21:46 > 0:21:51as far as we can tell, they made very little impression on anyone.

0:21:53 > 0:21:58Darwin spent the next year writing out his theory in detail.

0:21:58 > 0:22:00Then he sent the manuscript

0:22:00 > 0:22:03to his publisher, John Murray, whose firm, then as now,

0:22:03 > 0:22:08had offices in Albemarle Street, just off Piccadilly in London.

0:22:08 > 0:22:12Murray was the great publisher of his day,

0:22:12 > 0:22:16and dealt with the works of Jane Austen and Lord Byron,

0:22:16 > 0:22:20whose first editions still line these office walls.

0:22:20 > 0:22:27Darwin regarded his work as simply a summary, but even so it's 400 pages.

0:22:27 > 0:22:32It was published on November 24th, 1859.

0:22:33 > 0:22:36This is not a first edition - more's the pity.

0:22:36 > 0:22:40First editions are worth literally hundreds of thousands of pounds.

0:22:40 > 0:22:45This is a sixth edition - my copy, which I bought as a boy -

0:22:45 > 0:22:51when I was 18 I notice, and it cost me the princely sum of one shilling.

0:22:56 > 0:23:01The first edition of 1,250 copies sold out immediately

0:23:01 > 0:23:05and it went for a reprint, and then another reprint and another reprint.

0:23:05 > 0:23:08It's a book that contains very few technical terms -

0:23:08 > 0:23:11it's easily understood by anybody,

0:23:11 > 0:23:15and predictably it caused an outrage,

0:23:15 > 0:23:19not only throughout this country but indeed all the civilised world.

0:23:22 > 0:23:24What scandalised people most, it seems,

0:23:24 > 0:23:27was the implication that human beings

0:23:27 > 0:23:30were not specially created by God,

0:23:30 > 0:23:32as the Book of Genesis stated,

0:23:32 > 0:23:35but were descended from ape-like ancestors -

0:23:35 > 0:23:39a notion that provided a lot of scope for cartoonists.

0:23:41 > 0:23:44The leaders of the Church, headed by Samuel Wilberforce,

0:23:44 > 0:23:48the Bishop of Oxford, attacked it on the grounds that it demoted God

0:23:48 > 0:23:52and contradicted the story of creation as told by the Bible.

0:23:55 > 0:23:58"That Mr Darwin should have wandered from this broad

0:23:58 > 0:24:00"highway of nature's works

0:24:00 > 0:24:03"into the jungle of fanciful assumption,

0:24:03 > 0:24:05"is no small evil."

0:24:05 > 0:24:08"I have read your book with more pain than pleasure."

0:24:08 > 0:24:13"It is the frenzied inspiration of the inhaler of mephitic gas."

0:24:13 > 0:24:14"Fails utterly."

0:24:18 > 0:24:23Darwin's theory implied that life had originated in simple forms

0:24:23 > 0:24:27and had then become more and more complex.

0:24:27 > 0:24:31He knew perfectly well that the whole idea of evolution

0:24:31 > 0:24:34raised a lot of questions.

0:24:34 > 0:24:38In fact, some of those questions would not be answered

0:24:38 > 0:24:40until comparatively recently,

0:24:40 > 0:24:44but in his own time many distinguished scientists raised

0:24:44 > 0:24:47what seemed to be insuperable difficulties.

0:24:47 > 0:24:50And foremost among them was Richard Owen, the man who,

0:24:50 > 0:24:5320 years earlier,

0:24:53 > 0:24:57had named the extinct ground sloth in honour of Darwin.

0:24:59 > 0:25:02Over the years the two men had developed a deep

0:25:02 > 0:25:07personal dislike of one another and had quarrelled frequently.

0:25:08 > 0:25:12It wasn't that Owen thought that the story of the Garden of Eden was

0:25:12 > 0:25:17literally correct, but nonetheless he was a deeply religious man.

0:25:20 > 0:25:24He had, after all, ensured that his museum which

0:25:24 > 0:25:28would display the wonders of creation, echoed in its design

0:25:28 > 0:25:32the great Christian cathedrals of medieval Europe.

0:25:41 > 0:25:46And Owen knew about the diversity of life.

0:25:46 > 0:25:50Indeed he had spent his whole career cataloguing it.

0:25:50 > 0:25:52But even so, he refused to believe

0:25:52 > 0:25:55that a species could change over time.

0:26:00 > 0:26:03Owen did not deny the sequence in which all these

0:26:03 > 0:26:05different species appeared.

0:26:05 > 0:26:10But he believed that each was separate, each divinely created.

0:26:10 > 0:26:14Darwin's theory, however, required that there should be connections

0:26:14 > 0:26:19not just between similar species, but between the great animal groups.

0:26:22 > 0:26:25If fishes and reptiles and birds

0:26:25 > 0:26:30and mammals had all evolved from one another, then surely there must be

0:26:30 > 0:26:34intermediate forms between those great groups -

0:26:34 > 0:26:36and they were missing.

0:26:36 > 0:26:37And then,

0:26:37 > 0:26:41just two years after the publication of The Origin of Species,

0:26:41 > 0:26:44Richard Owen himself purchased

0:26:44 > 0:26:48the most astonishing fossil for his museum.

0:26:51 > 0:26:55It had been found in this limestone quarry in Bavaria.

0:26:55 > 0:26:59The stone here splits into flat smooth leaves that have been

0:26:59 > 0:27:02used as roofing tiles since Roman times.

0:27:04 > 0:27:07Most are blank.

0:27:07 > 0:27:10But occasionally, when you split them apart,

0:27:10 > 0:27:12they reveal a shrimp or a fish.

0:27:14 > 0:27:16It's almost impossible to resist

0:27:16 > 0:27:21the temptation of pulling down almost every boulder you see

0:27:21 > 0:27:25and then opening it, like a book, to look at each unopened

0:27:25 > 0:27:31page to see whether maybe it contains yet another fossil.

0:27:37 > 0:27:40But this fossil was something unprecedented.

0:27:41 > 0:27:44It is still one of the greatest of the treasures

0:27:44 > 0:27:47that are stored in the Natural History Museum.

0:27:48 > 0:27:53And this is it, it's called Archaeopteryx.

0:27:53 > 0:27:59It has unmistakable feathers on its wings and down its tail.

0:28:00 > 0:28:04So Owen had no hesitation in calling it a bird,

0:28:04 > 0:28:08but it was unlike any other bird that anyone knew of.

0:28:08 > 0:28:12Because it had claws on the front of its wings and -

0:28:12 > 0:28:14as was later discovered -

0:28:14 > 0:28:18it didn't have a beak but jaws with teeth in it.

0:28:18 > 0:28:22And a line of bones supporting its tail.

0:28:23 > 0:28:27So it was part reptile, part bird.

0:28:28 > 0:28:32Here was the link between those two great groups

0:28:32 > 0:28:34that was no longer missing.

0:28:35 > 0:28:38Gosh, you really can see the filaments there.

0:28:44 > 0:28:46Other examples of the same creature

0:28:46 > 0:28:49show its feathers even more clearly.

0:28:50 > 0:28:55We know from the bones of Archaeopteryx that it was,

0:28:55 > 0:28:57at best, a very poor flyer.

0:28:57 > 0:29:00So it's not surprising that eventually it was

0:29:00 > 0:29:05superseded by more modern, more efficient birds.

0:29:05 > 0:29:09And that's the fate of these links between great groups.

0:29:09 > 0:29:14Eventually they become extinct and the only way we know

0:29:14 > 0:29:18they existed is from their fossilised remains.

0:29:18 > 0:29:23Even so, there is a bird alive today that illustrates

0:29:23 > 0:29:27the link between modern birds and reptiles.

0:29:30 > 0:29:34The hoatzin nests in the swamps of tropical South America.

0:29:34 > 0:29:37There are caiman in the water beneath,

0:29:37 > 0:29:40ready to snap up any chick that might fall from its nest,

0:29:40 > 0:29:43so an ability to hold on tight is very valuable.

0:29:43 > 0:29:47And the nestlings have a very interesting way of doing that.

0:29:48 > 0:29:51The young still have claws on the front

0:29:51 > 0:29:54of their wings, as Archaeopteryx did.

0:29:54 > 0:29:57Here is vivid evidence that the wings of birds are modified

0:29:57 > 0:30:00forelegs and once had toes with claws on them.

0:30:02 > 0:30:05There's another creature alive today that represents

0:30:05 > 0:30:08a link between the great animal groups,

0:30:08 > 0:30:11a descendant of a group of reptiles that took a different

0:30:11 > 0:30:15evolutionary course and evolved not feathers but fur -

0:30:15 > 0:30:17the platypus.

0:30:17 > 0:30:20When specimens of this creature first reached

0:30:20 > 0:30:24Europe from Australia at the very end of the 18th century,

0:30:24 > 0:30:26people refused to believe their eyes.

0:30:28 > 0:30:31They said it was a hoax - bits

0:30:31 > 0:30:36and pieces of different creatures rather crudely sewn together.

0:30:36 > 0:30:39And yet in a way those early sceptics were right.

0:30:39 > 0:30:42The platypus is the most extraordinary

0:30:42 > 0:30:43mixture of different animals.

0:30:43 > 0:30:47It's part mammal and part reptile, and so it can give us

0:30:47 > 0:30:50some idea of how the first mammals developed.

0:30:52 > 0:30:55When it comes to breed it does something that separates

0:30:55 > 0:30:58it from all other mammals except one.

0:30:58 > 0:31:03In its nest, deep in a burrow, it lays eggs.

0:31:03 > 0:31:06It's this that links the platypus with the reptiles,

0:31:06 > 0:31:09and this that entitles it to be regarded

0:31:09 > 0:31:11as the most primitive living mammal.

0:31:14 > 0:31:17So the links between the great animal groups are not,

0:31:17 > 0:31:23in fact, missing - but exist both as fossils and as living animals.

0:31:24 > 0:31:27Although the fossil record provides

0:31:27 > 0:31:34an answer to the problem of missing links it also posed a major problem.

0:31:34 > 0:31:37It started very abruptly.

0:31:37 > 0:31:40The earliest known fossils in Darwin's time came

0:31:40 > 0:31:46from a formation called the Cambrian and there were two main kinds,

0:31:46 > 0:31:50these, which look like fretsaw blades and are called graptolite

0:31:51 > 0:31:55and these like giant woodlice which are called trilobites.

0:31:56 > 0:31:57Could it really be,

0:31:57 > 0:32:02that life on Earth started with creatures as complex as these?

0:32:18 > 0:32:22As a boy, I was a passionate collector of fossils.

0:32:22 > 0:32:27I grew up in the city of Leicester and I knew

0:32:27 > 0:32:31that in this area, not far from the city called Charnwood Forest,

0:32:31 > 0:32:36there were the oldest rocks in the world, older even than the Cambrian.

0:32:36 > 0:32:41So therefore, by definition, they would be without fossils.

0:32:41 > 0:32:46There was no point in me looking for fossils in these ancient rocks.

0:33:02 > 0:33:05There were, it's true, very rarely,

0:33:05 > 0:33:09some rather odd shapes in these rocks, like this one here.

0:33:11 > 0:33:16But they were dismissed as being some kind of mechanical aberration.

0:33:16 > 0:33:20I mean, after all, how could there be anything living in these

0:33:20 > 0:33:22extremely ancient rocks?

0:33:24 > 0:33:30And then in 1957, a schoolboy with rather

0:33:30 > 0:33:36more patience and perspicacity than I had, found something really

0:33:36 > 0:33:41remarkable and undeniably the remains of a living creature.

0:33:44 > 0:33:47And here it is in Leicester Museum,

0:33:47 > 0:33:49where it's been brought for safe keeping.

0:33:49 > 0:33:51It's called Charnia.

0:33:51 > 0:33:57Who could doubt that this is the impression of a living organism?

0:33:58 > 0:34:02It has a central stem, branches on either side.

0:34:02 > 0:34:07In fact, it seems to have been something like the sea pens

0:34:07 > 0:34:09that today grow on coral reefs.

0:34:11 > 0:34:15Since its discovery a whole range of organisms have been

0:34:15 > 0:34:20found in rocks of this extreme age, not only here

0:34:20 > 0:34:24in the Charnwood Forest but in many other different parts of the world.

0:34:26 > 0:34:30Fossil hunters, searching these rocks in the Ediacara Hills

0:34:30 > 0:34:34of Australia had also been discovering other strange shapes.

0:34:36 > 0:34:40At first many scientists refused to believe that these

0:34:40 > 0:34:43faint impressions were the remains of jellyfish.

0:34:43 > 0:34:48But by now enough specimens had been discovered to make quite sure

0:34:48 > 0:34:50that, that indeed is what they are.

0:34:58 > 0:35:01So now we know that life did not begin suddenly with

0:35:01 > 0:35:04those complex animals of the Cambrian.

0:35:06 > 0:35:11It started much, much earlier, first with simple microscopic forms

0:35:11 > 0:35:15which eventually became bigger but which were still so soft

0:35:15 > 0:35:19and delicate that they only very rarely left any mark in the rocks.

0:35:22 > 0:35:26The question of the age of the earth posed another

0:35:26 > 0:35:28problem for Darwin's theory.

0:35:28 > 0:35:33In the 17th century, an Irish bishop had used the genealogies

0:35:33 > 0:35:37recorded in the Bible that lead back to Adam to work out that the

0:35:37 > 0:35:43week of creation must have taken place in the year 4004 BC.

0:35:43 > 0:35:47That may seem to us to be a very naive way of doing things

0:35:47 > 0:35:49but what other method was there anyway?

0:35:50 > 0:35:54The Victorian geologists had already concluded that the

0:35:54 > 0:35:56earth must be millions of years old.

0:35:56 > 0:35:59But how many millions, no-one could say.

0:36:00 > 0:36:04Then, less than 50 years after the publication

0:36:04 > 0:36:07of The Origin, a discovery was made in what seemed a totally

0:36:07 > 0:36:12disconnected branch of science that would ultimately provide the answer.

0:36:13 > 0:36:17A Polish woman working in Paris, Marie Curie,

0:36:17 > 0:36:21discovered that some rocks contained an element called uranium that

0:36:21 > 0:36:26decays over time at a steady rate through a process called radiation.

0:36:28 > 0:36:32Today, a century after she made her extraordinary

0:36:32 > 0:36:35discovery, the method of dating by measuring

0:36:35 > 0:36:38changes in radioactivity has become greatly refined.

0:36:42 > 0:36:45This is a sample taken from those very ancient

0:36:45 > 0:36:47rocks in Charnwood Forest...

0:36:48 > 0:36:51..and these tiny crystals are revealed to be

0:36:51 > 0:36:56562 million years old.

0:36:56 > 0:37:00That provides more than enough time for natural selection to

0:37:00 > 0:37:04produce the procession of fossils that eventually leads to the

0:37:04 > 0:37:06living animals and plants we know today.

0:37:08 > 0:37:11But there was another objection.

0:37:11 > 0:37:16If all animals within a group have a common origin, how is it that

0:37:16 > 0:37:20some kinds of animals are distributed throughout

0:37:20 > 0:37:24the continents of the world except for Antarctica.

0:37:24 > 0:37:30How is it that, for example, frogs in Europe and Africa are also found

0:37:30 > 0:37:34in South America on the other side of the Atlantic Ocean, bearing in

0:37:34 > 0:37:39mind that frogs have permeable skins and can't survive in sea water?

0:37:41 > 0:37:44Darwin himself had a couple of suggestions.

0:37:44 > 0:37:48One was that they might have floated across accidentally on rafts

0:37:48 > 0:37:51of vegetation and the other is that maybe there were land

0:37:51 > 0:37:54bridges between the continents,

0:37:54 > 0:37:57but even he was not convinced by either explanation.

0:38:04 > 0:38:09Even as late as 1947 when I was a geology student

0:38:09 > 0:38:13here at Cambridge there was no convincing explanation.

0:38:13 > 0:38:20It's true that back in 1912 a German geologist had suggested that at one

0:38:20 > 0:38:26time in the very remote distant past all the continents of the earth that

0:38:26 > 0:38:31we know today were grouped together to form one huge supercontinent

0:38:31 > 0:38:36and that over time this broke up and the pieces drifted apart.

0:38:37 > 0:38:40That would have provided an answer.

0:38:41 > 0:38:45But when I asked the Professor of Geology here who was

0:38:45 > 0:38:48lecturing to us why he didn't tell us about that in his lectures

0:38:48 > 0:38:51he replied, rather loftily I must say,

0:38:51 > 0:38:55"When you can demonstrate to me that there is a

0:38:55 > 0:39:00"force on earth that can move the continents by a millimetre I

0:39:00 > 0:39:05"will consider it but until then the idea is sheer moonshine, dear boy!"

0:39:08 > 0:39:12But then in the 1960s it became possible to map

0:39:12 > 0:39:17the sea floor in detail and it was discovered not only that the

0:39:17 > 0:39:21continents have shifted, in just the way that the German geologist

0:39:21 > 0:39:24had suggested but that they were still moving.

0:39:26 > 0:39:30New rock wells up from deep below the earth's crust

0:39:30 > 0:39:33and flows away on either side of the mid ocean ridges,

0:39:33 > 0:39:35carrying the continents with it.

0:39:37 > 0:39:41Amphibians had originally evolved on this super continent

0:39:41 > 0:39:43and had then travelled on each of its various

0:39:43 > 0:39:45fragments as they drifted apart.

0:39:46 > 0:39:47Problem solved!

0:39:52 > 0:39:55Perhaps the biggest problem of all for most people

0:39:55 > 0:40:01was the argument put forward for the existence of God at the beginning

0:40:01 > 0:40:06of the 19th century by an Anglican clergyman called William Paley.

0:40:06 > 0:40:09He said supposing you were walking in the countryside

0:40:09 > 0:40:12and you picked up something like this.

0:40:13 > 0:40:18You would know from looking at it that it had been designed to

0:40:18 > 0:40:19tell the time.

0:40:23 > 0:40:26There must, therefore, be a designer

0:40:26 > 0:40:29and the same argument would apply if you

0:40:29 > 0:40:32looked at one of the intricate structures found in nature, such as

0:40:32 > 0:40:38the human eye and the only designer of the human eye could be God.

0:40:39 > 0:40:43Anti-evolutionists maintain that the eye would

0:40:43 > 0:40:47only work if it was complete in all its details.

0:40:48 > 0:40:51Darwin on the other hand argued that the eye had developed,

0:40:51 > 0:40:57becoming increasingly complex over a long period of time.

0:40:57 > 0:41:01That would only work if each stage of development was

0:41:01 > 0:41:04an improvement on the previous one and today we know

0:41:04 > 0:41:09enough about the animal kingdom to know that, that is indeed the case.

0:41:11 > 0:41:14Some very simple animals have nothing more

0:41:14 > 0:41:17than light-sensitive spots that enable them

0:41:17 > 0:41:20to tell the difference between light and dark.

0:41:20 > 0:41:25But if a patch of such spots formed even the shallowest of pits,

0:41:25 > 0:41:27one edge of the pit would throw a shadow

0:41:27 > 0:41:30and so reveal the direction of light.

0:41:31 > 0:41:34If the pit got deeper and started to close,

0:41:34 > 0:41:38then light would form a blurred image.

0:41:38 > 0:41:42Mucus secreted by the cells would bend the light and focus it.

0:41:42 > 0:41:46If this mucus hardened it would form a proper lens

0:41:46 > 0:41:49and transmit a brighter and clearer image.

0:41:51 > 0:41:54All these different fully functional stages at different

0:41:54 > 0:41:58levels of complexity are found in living animals today.

0:41:59 > 0:42:02This single-celled creature has one of those

0:42:02 > 0:42:03light-sensitive spots.

0:42:04 > 0:42:09Flatworms have a small pit containing light spots,

0:42:09 > 0:42:12so they can detect the shadow of a predator.

0:42:12 > 0:42:15A snail's blurry vision is good enough to enable

0:42:15 > 0:42:18it to find its way to food, and the octopus

0:42:19 > 0:42:24has an eye with a proper lens and can see as much detail as we can.

0:42:29 > 0:42:32So the structure of the human eye does not demand

0:42:32 > 0:42:35the assistance of a supernatural designer.

0:42:35 > 0:42:38It can have evolved gradually with each stage bringing a real

0:42:38 > 0:42:42advantage - as Darwin's theory demands.

0:42:48 > 0:42:51Natural selection, of course, requires that an

0:42:51 > 0:42:55animal's characteristics are handed from one generation to the next.

0:42:56 > 0:42:59It's obvious that children resemble their parents.

0:42:59 > 0:43:01Anyone knows that.

0:43:01 > 0:43:04But when you come to think of it, how does that come about?

0:43:06 > 0:43:09In Darwin's time nobody had the faintest

0:43:09 > 0:43:13idea about the mechanism or the rules that governed that

0:43:13 > 0:43:17process, except perhaps for one man who was

0:43:17 > 0:43:22working in the city of Brno in what is now the Czech Republic

0:43:22 > 0:43:27at exactly the same time that Darwin was writing his book in Kent.

0:43:27 > 0:43:30That man's name was Gregor Mendel.

0:43:32 > 0:43:35He discovered the laws of inheritance by breeding

0:43:35 > 0:43:37thousands of pea plants

0:43:37 > 0:43:40and observing how they changed from one generation to the next.

0:43:42 > 0:43:45He found that while many characteristics were

0:43:45 > 0:43:48passed down directly from one generation to another,

0:43:48 > 0:43:51others could actually skip a generation.

0:43:51 > 0:43:52How could that happen?

0:43:54 > 0:43:58Mendel explained this by suggesting that each plant,

0:43:58 > 0:44:02each organism, contained within it factors which were

0:44:02 > 0:44:06responsible for creating those particular characteristics.

0:44:08 > 0:44:13Today we call those things genes but nobody had any idea how

0:44:13 > 0:44:17they worked until 100 years after Mendel's time

0:44:17 > 0:44:21and then the answer was discovered in Cambridge.

0:44:26 > 0:44:28In 1953, here in the Cavendish laboratories,

0:44:30 > 0:44:32two young researchers, Francis Crick

0:44:32 > 0:44:36and James Watson were building models like this.

0:44:37 > 0:44:42It was their way of thinking about and investigating the structure

0:44:42 > 0:44:48of a complex molecule that's found in the genes of all animals - DNA.

0:44:50 > 0:44:55The crucial bit are these chains, which encircle the rod.

0:44:59 > 0:45:06And here is a second and entwine. This is a double helix.

0:45:08 > 0:45:12The workings of the DNA molecule are now understood in

0:45:12 > 0:45:16such detail that we can demonstrate something that is truly astounding.

0:45:18 > 0:45:21A gene taken from one animal can function in another.

0:45:23 > 0:45:27The gene that causes a jellyfish to be luminous, for example,

0:45:27 > 0:45:31transplanted into a mouse, will make that mouse luminous.

0:46:35 > 0:46:38So, 150 years after the publication of Darwin's

0:46:38 > 0:46:45revolutionary book, modern genetics has confirmed its fundamental

0:46:45 > 0:46:51truth - all life is related and it enables us to construct with

0:46:51 > 0:46:57confidence the complex tree that represents the history of life.

0:46:58 > 0:47:03It began in the sea, some 3,000 million years ago.

0:47:04 > 0:47:09Complex chemical molecules began to clump together to form

0:47:09 > 0:47:12microscopic blobs.

0:47:12 > 0:47:13Cells.

0:47:14 > 0:47:18These were the seeds from which the tree of life developed.

0:47:18 > 0:47:23They were able to split, replicating themselves as bacteria do

0:47:23 > 0:47:27and as time passed they diversified into different groups.

0:47:29 > 0:47:31Some remained attached to one another

0:47:31 > 0:47:35so that they formed chains, we know them today as algae.

0:47:36 > 0:47:41Others formed hollow balls which collapsed upon themselves

0:47:41 > 0:47:43creating a body with an internal cavity.

0:47:44 > 0:47:47They were the first multi-celled organisms -

0:47:47 > 0:47:50sponges are their direct descendents.

0:47:52 > 0:47:54As more variations appeared,

0:47:54 > 0:47:57the tree of life grew and became more diverse.

0:47:58 > 0:48:00Some organisms became more mobile

0:48:00 > 0:48:03and developed a mouth that opened into a gut.

0:48:07 > 0:48:10Others had bodies stiffened by an internal rod.

0:48:11 > 0:48:16They, understandably, developed sense organs around their front end.

0:48:17 > 0:48:20A related group had bodies that were

0:48:20 > 0:48:23divided into segments with little projections on either side that

0:48:23 > 0:48:25helped them to move around on the sea floor.

0:48:27 > 0:48:29Some of these segmented creatures developed hard

0:48:29 > 0:48:33protective skins which gave their bodies some rigidity.

0:48:34 > 0:48:38So now the seas were filled with a great variety of animals.

0:48:40 > 0:48:44And then around 450 million years ago, some of these

0:48:44 > 0:48:49armoured creatures crawled up, out of the water and ventured onto land.

0:48:52 > 0:48:53And here,

0:48:53 > 0:48:56the tree of life branched into a multitude of different

0:48:56 > 0:49:00species that exploited this new environment in all kinds of ways.

0:49:03 > 0:49:06One group of them developed elongated flaps on their

0:49:06 > 0:49:10backs which over many generations eventually developed into wings.

0:49:12 > 0:49:14The insects had arrived.

0:49:15 > 0:49:19Life moved into the air and diversified into myriad forms.

0:49:22 > 0:49:26Meanwhile, back in the seas, those creatures with the stiffening

0:49:26 > 0:49:32rod in their bodies had strengthened it by encasing it in bone.

0:49:32 > 0:49:37A skull developed with a hinged jaw that could grab and hold on to prey.

0:49:39 > 0:49:40They grew bigger

0:49:40 > 0:49:44and developed fins, equipped with muscles that enabled them to swim

0:49:44 > 0:49:50with speed and power so fish now dominated the waters of the world.

0:49:52 > 0:49:53One group of them

0:49:53 > 0:49:56developed the ability to gulp air from the water surface.

0:50:00 > 0:50:03Their fleshy fins became weight-supporting legs

0:50:03 > 0:50:08and 375 million years ago a few of these backbone creatures

0:50:08 > 0:50:11followed the insects onto the land.

0:50:12 > 0:50:16They were amphibians with wet skins and they had to return to water

0:50:16 > 0:50:22to lay their eggs, but some of their descendents evolved dry, scaly skins

0:50:22 > 0:50:27and broke their link with water by laying eggs with watertight shells.

0:50:29 > 0:50:32These creatures, the reptiles, were the ancestors of today's

0:50:32 > 0:50:35tortoises, snakes, lizards and crocodiles.

0:50:36 > 0:50:40And, of course, they included the group that back

0:50:40 > 0:50:43then, came to dominate the land - the dinosaurs.

0:50:46 > 0:50:50But 65 million years ago a great disaster overtook the earth.

0:50:56 > 0:50:57Whatever its cause,

0:50:57 > 0:51:00a great proportion of animals were exterminated.

0:51:00 > 0:51:03All the dinosaurs disappeared except for one

0:51:03 > 0:51:06branch, whose scales had become modified into feathers.

0:51:08 > 0:51:10They were the birds.

0:51:10 > 0:51:14While they spread through the skies a small, seemingly

0:51:14 > 0:51:16insignificant group of survivors began to

0:51:16 > 0:51:19increase in numbers on the ground beneath.

0:51:20 > 0:51:23These creatures differed from their competitors

0:51:23 > 0:51:28in that their bodies were warm and insulated with coats of fur,

0:51:28 > 0:51:30they were the first mammals.

0:51:30 > 0:51:34With much of the land left vacant after the great catastrophe

0:51:34 > 0:51:36they now had their chance.

0:51:37 > 0:51:39Their warm insulated bodies enabled them

0:51:39 > 0:51:44to be active at all times, at night as well as during the day

0:51:44 > 0:51:49and in all places, from the Arctic to the tropics.

0:51:49 > 0:51:53In water as well as on land.

0:51:53 > 0:51:56On grassy plains and up in the trees.

0:52:37 > 0:52:41There can be no doubt about our close relationship

0:52:41 > 0:52:43to these chimpanzees.

0:52:43 > 0:52:48Our bodies are so similar, the proportions of our limbs

0:52:48 > 0:52:53or our faces may differ, but otherwise we are very, very similar.

0:52:53 > 0:52:57The arrangement of our internal organs, the chemistry of our blood,

0:52:57 > 0:53:03the way our bodies work, all these are almost identical

0:53:03 > 0:53:06and DNA confirms that.

0:53:06 > 0:53:11Indeed we are as closely related to chimpanzees

0:53:11 > 0:53:15and the rest of the apes and monkeys as say lions are to tigers

0:53:15 > 0:53:18and to the rest of the cat family.

0:53:42 > 0:53:46Suddenly an image from our remote past comes vividly

0:53:46 > 0:53:49to light at the time when our distant

0:53:49 > 0:53:52ancestors, in order to keep up with the changing environment, had

0:53:52 > 0:53:58to wade and keep their heads above water in order to find food.

0:53:58 > 0:54:03That crucial moment when our far distant ancestors took a step

0:54:03 > 0:54:07away from being apes and a step towards humanity.

0:54:23 > 0:54:26The Natural History Museum is one of the most

0:54:26 > 0:54:29important museums of its kind in the world.

0:54:29 > 0:54:31Richard Owen brought it into existence,

0:54:31 > 0:54:35but over a century later, discoveries from many

0:54:35 > 0:54:39branches of science have shown that his belief that species can

0:54:39 > 0:54:43never change but always remain exactly the same was mistaken.

0:54:58 > 0:55:02It was Charles Darwin's profound insights that have

0:55:02 > 0:55:04proved to be true.

0:55:04 > 0:55:08And now, to mark the 200th anniversary of his birth,

0:55:08 > 0:55:13his statue is being taken from its out-of-the-way location to be

0:55:13 > 0:55:16placed centre stage in the main hall.

0:55:28 > 0:55:30Darwin's great insight revolutionised

0:55:30 > 0:55:33the way in which we see the world.

0:55:33 > 0:55:36We now understand why there are so many different species,

0:55:36 > 0:55:40why they are distributed in the way they are around the world

0:55:40 > 0:55:44and why their bodies and our bodies are shaped in the way that they are.

0:55:46 > 0:55:49Because we understand that bacteria evolve,

0:55:49 > 0:55:53we can devise methods of dealing with the diseases they cause

0:55:53 > 0:55:57and because we can disentangle the complex relationships between

0:55:57 > 0:56:01animals and plants in a natural community we can foresee some

0:56:01 > 0:56:05of the consequences when we start to interfere with those communities.

0:56:07 > 0:56:11But above all Darwin has shown us that we are not

0:56:11 > 0:56:16apart from the natural world - we do not have dominion over it.

0:56:17 > 0:56:22We are subject to its laws and processes as are all other

0:56:22 > 0:56:27animals on earth to which indeed we are related.

0:56:29 > 0:56:31HE LAUGHS

0:56:50 > 0:56:55He was an extraordinary person living there in Downe in Kent.

0:56:55 > 0:56:58And yet communicating with naturalists

0:56:58 > 0:57:03all over the world by post which took weeks

0:57:03 > 0:57:06to meet different people and to produce

0:57:06 > 0:57:10at the end this very beautifully written book.

0:57:12 > 0:57:15The last paragraph of this book, you know,

0:57:15 > 0:57:18is a great piece of literature.

0:57:18 > 0:57:20It's a great piece of prose

0:57:20 > 0:57:25and it contains a really profound truth

0:57:25 > 0:57:29that's worth pondering. Should I read it?

0:57:45 > 0:57:50"There is grandeur in this view of life, with its several powers,

0:57:50 > 0:57:54"having been originally breathed by the Creator

0:57:54 > 0:57:58"into a few forms or into one;

0:57:58 > 0:58:03"and that, whilst this planet has gone cycling on according

0:58:03 > 0:58:10"to the fixed law of gravity, from so simple a beginning endless forms

0:58:10 > 0:58:17"most beautiful and most wonderful have been, and are being, evolved."