0:00:04 > 0:00:09Most fossils are just the hard bits that nature leaves behind,
0:00:09 > 0:00:11shells like these.
0:00:11 > 0:00:15The other parts of the organism, the soft parts if you like,
0:00:15 > 0:00:19feathers, guts and many kinds of organisms that are soft- bodied,
0:00:19 > 0:00:21leave no trace behind.
0:00:21 > 0:00:24Except in a few very special places.
0:00:25 > 0:00:28And it is to these places that we are going to travel
0:00:28 > 0:00:31in search of windows into the past.
0:00:35 > 0:00:37From 8,000 feet up in the Rocky Mountains...
0:00:39 > 0:00:42..to China's most eccentric museums.
0:00:42 > 0:00:47- What is going on here?- Yeah, yeah, yeah, this is a dinosaur egg.- Ah!
0:00:51 > 0:00:54To the richest seams of fossils discovered in Europe.
0:00:58 > 0:01:03Each of these unique fossil sites represents a snapshot
0:01:03 > 0:01:05of an ancient vanished world.
0:01:06 > 0:01:10A moment of time captured in rock.
0:01:10 > 0:01:14Ah!
0:01:14 > 0:01:16And filled with fossil treasures.
0:01:20 > 0:01:24We'll see fossils exposed by the latest techniques.
0:01:27 > 0:01:30And uncover those recently made to order.
0:01:30 > 0:01:33- You mean this is a fake? - It's a fake.
0:01:33 > 0:01:36Wow, look at that!
0:01:36 > 0:01:39We'll also reveal some spectacular surprises.
0:01:39 > 0:01:41Sometimes the scale of the show
0:01:41 > 0:01:45really does match the scale of geological time.
0:01:48 > 0:01:51To learn about these creatures from the past,
0:01:51 > 0:01:55we'll meet their distant descendants still living.
0:01:55 > 0:01:58This animal has tracked the habitat it liked.
0:01:58 > 0:02:03And, in the name of science, I'll eat a few too.
0:02:05 > 0:02:08These rare, exquisitely preserved fossils
0:02:08 > 0:02:12are found in just a few very special places in the world.
0:02:13 > 0:02:17Extraordinary sites that have revolutionised
0:02:17 > 0:02:19our ability to see into the past.
0:02:19 > 0:02:23- It looks as delicate as a ballet dancer, doesn't it?- Yes.
0:02:23 > 0:02:27- And yet this poor animal probably died in agony.- Yeah.
0:02:27 > 0:02:31But rather than see through a glass darkly,
0:02:31 > 0:02:35we will confront the ancient past face to face.
0:02:52 > 0:02:59At the beginning of the last century the origins of complex life were a mystery.
0:02:59 > 0:03:03But here, 8,000 feet up in the Rocky Mountains of Canada,
0:03:03 > 0:03:07a site was discovered that overturned our views
0:03:07 > 0:03:10of the origins of complex life.
0:03:12 > 0:03:18Canada's Burgess Shale is one of the greatest fossil sites in the world.
0:03:18 > 0:03:23Now elevated in the clouds, this ancient sea bed contains
0:03:23 > 0:03:26some of the most bizarre animals ever to be discovered,
0:03:26 > 0:03:30trapped in rock when they were buried alive
0:03:30 > 0:03:33more than 500 million years ago.
0:03:33 > 0:03:36But what were a series of catastrophes for them
0:03:36 > 0:03:39provided a miracle for our understanding.
0:04:01 > 0:04:04Until the early 20th century
0:04:04 > 0:04:07scientists knew little of complex early life.
0:04:11 > 0:04:16Then, in 1909, a fossil site was unearthed
0:04:16 > 0:04:19like none that had ever been found before.
0:04:26 > 0:04:30Buried within it were strange soft-bodied life forms
0:04:30 > 0:04:34that challenged previous assumptions about how animals evolved...
0:04:36 > 0:04:39..processes of fossilisation
0:04:39 > 0:04:41and the richness of early life.
0:05:06 > 0:05:09The place where this discovery was made
0:05:09 > 0:05:12lies in Canada's Yoho National Park.
0:05:17 > 0:05:21It's a rugged part of the Northern Rockies whose highest peaks
0:05:21 > 0:05:24rise nearly 12,000 feet into the clouds.
0:05:26 > 0:05:29Back in the late 1800s,
0:05:29 > 0:05:33the little village of Field was just starting out,
0:05:33 > 0:05:36built largely by railroad workers,
0:05:36 > 0:05:39making Canada's Transcontinental Railway.
0:05:42 > 0:05:45Long freight trains still run through here today.
0:05:48 > 0:05:51And it may have been surveyors working for the railroads
0:05:51 > 0:05:54that stumbled upon the first fossilised clues,
0:05:54 > 0:05:57that there was something special hidden in the mountains.
0:06:02 > 0:06:07It's a misty morning in the town of Field in Kicking Horse Pass
0:06:07 > 0:06:10in the Rocky Mountains of Canada.
0:06:10 > 0:06:15Behind me, the mountains rise, mysterious, invincible,
0:06:15 > 0:06:17unreachable, you might think.
0:06:19 > 0:06:22I'm full of admiration for those 19th century geologists
0:06:22 > 0:06:26who scaled these peaks in search of mineral treasure.
0:06:26 > 0:06:31Now I've got to go up there myself in search of the famous Burgess Shale.
0:06:39 > 0:06:42The discovery that changed our understanding of the origins
0:06:42 > 0:06:46of complex life was made by Charles Doolittle Walcott.
0:06:47 > 0:06:53Born into a poor family in 1850, Walcott worked himself up
0:06:53 > 0:06:56from being a self-educated geologist's assistant,
0:06:56 > 0:07:03to head of the Smithsonian Institution in Washington DC in 1907.
0:07:07 > 0:07:11Backed by the resources of the USA's wealthiest museum,
0:07:11 > 0:07:16that same year he launched a series of field expeditions
0:07:16 > 0:07:19deep into the Rocky Mountains, hunting for fossils.
0:07:29 > 0:07:32The site he eventually discovered a year later
0:07:32 > 0:07:34can be viewed from nearby Emerald Lake.
0:07:39 > 0:07:43It registers as little more than a tiny slash of exposed rock
0:07:43 > 0:07:46among the shaley slopes of Mount Burgess.
0:07:47 > 0:07:51And that's the nearest all but the hardiest hikers will ever get.
0:07:54 > 0:07:58To make the daunting journey up to 8,000 feet,
0:07:58 > 0:08:02I'm taking my chances with another mode of transport.
0:08:27 > 0:08:31Travelling with me is one of the world's foremost experts on the Burgess Shale.
0:08:33 > 0:08:37Jean-Bernard Caron from Canada's Royal Ontario Museum.
0:08:42 > 0:08:44The flight is wondrous.
0:08:46 > 0:08:50Rarely does the local weather allow such a panoramic view
0:08:50 > 0:08:52over the Canadian Rockies.
0:08:55 > 0:08:58I'm told conditions like this are so rare,
0:08:58 > 0:09:03no-one has landed a helicopter in the small mountainside quarry
0:09:03 > 0:09:06that now bears Walcott's name, for several years.
0:09:22 > 0:09:26It's a long time since I've been here and it still amazes me
0:09:26 > 0:09:30that Walcott was able to locate this fossil bed
0:09:30 > 0:09:34in this vast area of exposure
0:09:34 > 0:09:37and hone it down to one particular place.
0:09:40 > 0:09:44Walcott's quarry has since been expanded several times over.
0:09:46 > 0:09:50But the original wall he excavated still stands today.
0:09:51 > 0:09:56So this is one of the holy sites of palaeontology.
0:09:56 > 0:09:59Walcott's original quarry.
0:09:59 > 0:10:03That's right. This is the wall of this quarry as he left it
0:10:03 > 0:10:08when he last came to this place in the 1920s.
0:10:08 > 0:10:14And you can see all these bands here which represent like a rapid burial
0:10:14 > 0:10:18of, you know, mud that will have entombed a lot of fossils.
0:10:18 > 0:10:21And this dark band here, it looks like,
0:10:21 > 0:10:25almost like a layer of chocolate in a chocolate cake, doesn't it?
0:10:26 > 0:10:31- And like that chocolate, it's rich - in fossils.- Extremely rich.
0:11:02 > 0:11:05The richness of the discoveries Walcott would make
0:11:05 > 0:11:09over the next 15 years, would astound the scientific world.
0:11:13 > 0:11:17To understand their impact we must go to the other side of the world,
0:11:17 > 0:11:20to a few decades before Walcott was born.
0:11:23 > 0:11:25The rugged Pembrokeshire coast of Western Wales
0:11:25 > 0:11:28is a place I know well.
0:11:29 > 0:11:33It's composed of rocks as old as the Burgess Shale.
0:11:39 > 0:11:42These are some of the most magnificent cliffs in Britain,
0:11:42 > 0:11:45on the tip of Western Wales.
0:11:46 > 0:11:50In the 19th century they yielded some of the first fossils,
0:11:50 > 0:11:54the oldest fossils, that had ever been found in the United Kingdom.
0:11:55 > 0:12:01They were called Cambrian because Cambria was the Roman name for Wales.
0:12:01 > 0:12:06Nowadays, all around the world Cambrian is recognised
0:12:06 > 0:12:11for this very, very important early period in the history of evolution.
0:12:13 > 0:12:16Now we're going to sneak ashore to see if we can actually discover
0:12:16 > 0:12:19some of these very ancient fossils.
0:12:19 > 0:12:25And we're just hoping that the notoriously fickle Welsh weather holds out for us.
0:12:40 > 0:12:44Geologists first mapped these rocky Cambrian coves in the 1860s.
0:12:47 > 0:12:50They were the first to uncover some of the oldest fossils
0:12:50 > 0:12:56in the world - fossils that include my own speciality.
0:12:56 > 0:12:59The trilobites.
0:12:59 > 0:13:02Hard-shelled and with segmented bodies,
0:13:02 > 0:13:06they moulted as they grew like modern-day crabs or lobsters.
0:13:10 > 0:13:14These extinct marine invertebrates were one of the most successful
0:13:14 > 0:13:16and diverse groups that ever lived.
0:13:23 > 0:13:28But finding them usually involves a drenching of one kind or another.
0:13:28 > 0:13:31God!
0:13:34 > 0:13:36Ah-ha-ha!
0:13:38 > 0:13:40An empty rock.
0:13:40 > 0:13:42Trilobites have been preserved here
0:13:42 > 0:13:46because they possessed a hard exoskeleton.
0:13:46 > 0:13:50Such hard parts are the raw material of most fossils.
0:13:51 > 0:13:53But they are not common.
0:13:57 > 0:14:01Eventually my diligence and perseverance are rewarded.
0:14:01 > 0:14:03Ah-ha! Not a bad break, actually.
0:14:05 > 0:14:10But these are some of the hardest rocks to find fossils in.
0:14:10 > 0:14:14I've been looking for a solid hour and I've just found a hint,
0:14:14 > 0:14:20just a fragment, but a large fragment, of this trilobite animal.
0:14:20 > 0:14:23It's exciting to find even that - to think that it's survived
0:14:23 > 0:14:27more than 500 million years of the vicissitudes time can throw at it.
0:14:32 > 0:14:36Fortunately, thanks to the National Museum of Wales,
0:14:36 > 0:14:39here's one someone else found earlier.
0:14:39 > 0:14:46This magnificent specimen was found by a lucky collector in this very locality.
0:14:46 > 0:14:51It's a trilobite, of course. It's Britain's largest trilobite,
0:14:51 > 0:14:53which grew sometimes to nearly
0:14:53 > 0:14:55three quarters of a metre in length.
0:14:55 > 0:14:58It's name, Paradoxides,
0:14:58 > 0:15:00because the original discoverer
0:15:00 > 0:15:02found it somewhat paradoxical.
0:15:09 > 0:15:13A high number of trilobite fossils found here in Wales
0:15:13 > 0:15:19helped convince 19th century scientists that trilobites dominated the Cambrian world.
0:15:19 > 0:15:22Almost to the exclusion of anything else.
0:15:28 > 0:15:33Trilobites were also some of Walcott's first finds in the Rocky Mountains,
0:15:33 > 0:15:37though their unusual features piqued his curiosity.
0:15:47 > 0:15:51Today, the world's premier collection of Burgess Shale fossils
0:15:51 > 0:15:55is housed in Canada's Royal Ontario Museum.
0:15:59 > 0:16:03Almost all are tucked away behind the scenes,
0:16:03 > 0:16:06awaiting a new gallery to show them off in all their glory.
0:16:17 > 0:16:20In the meantime, while funds are raised,
0:16:20 > 0:16:23they're kept under the watchful eye of Peter Fenton,
0:16:23 > 0:16:27whose domain includes millions of years of fossil history.
0:16:32 > 0:16:35So we just come this way through the vert prep lab
0:16:35 > 0:16:39and we've got everything from people prepping casts, cleaning up casts
0:16:39 > 0:16:42and moulds, to actually prepping specimens.
0:16:42 > 0:16:47And then just everything requiring a lot of patience and a steady hand.
0:16:47 > 0:16:53I feel rather like a hungry boy in Willy Wonka's Chocolate Factory.
0:16:53 > 0:16:58And here we are! So these are the invertebrate fossil collections.
0:16:58 > 0:17:03- And then...- Oh, look at that! That is something.
0:17:03 > 0:17:06- That's one of our favourites. - Sea scorpions - a whole line.- Yes.
0:17:06 > 0:17:11It's a death assemblage, I think, because they're all just lying there
0:17:11 > 0:17:14un-moulted, all the bits and pieces still in place.
0:17:15 > 0:17:19Plus we've got, you know, plants, animals. It kind of...
0:17:19 > 0:17:24- Some of these things are like pieces of sculpture, aren't they? - Oh, they're beautifully prepared.
0:17:24 > 0:17:30So... This is just one of the many rows, upon rows, upon rows
0:17:30 > 0:17:34of Burgess material. We probably have upwards of 150,000.
0:17:34 > 0:17:41- 150,000?- Each specimen marked with the level it comes from.- Yeah.
0:17:41 > 0:17:44I know from my own experience if you don't mark every piece of rock,
0:17:44 > 0:17:46- you put it down in the wrong place, you're doomed!- Well that's it.
0:17:46 > 0:17:52So we have some beautiful specimens.
0:17:52 > 0:17:56Amid these vast collections are also some old friends,
0:17:56 > 0:17:59fossils and scholars alike.
0:17:59 > 0:18:02- Er, trilobites down this way.- Oh!
0:18:02 > 0:18:07Like myself, David Rudkin is a trilobite man.
0:18:07 > 0:18:14So this is the kind of slab that makes a trilobite man's mouth water.
0:18:14 > 0:18:17In fact, I want to take it home.
0:18:17 > 0:18:23Several specimens dotted at various angles,
0:18:23 > 0:18:28and it's this, isn't it, that brought Walcott out West?
0:18:28 > 0:18:32Eventually yes, after others had published and written on these,
0:18:32 > 0:18:35Walcott took some exception to both the identity
0:18:35 > 0:18:38of some of the trilobites and their age, and wanted to find out
0:18:38 > 0:18:43for himself what was really going on, and this is what he would have seen.
0:18:43 > 0:18:46But Walcott would soon discover trilobites
0:18:46 > 0:18:48like he'd never seen before.
0:18:48 > 0:18:52Well, this is the kind of regular Cambrian, if you like, isn't it?
0:18:52 > 0:18:58- Indeed it is yes.- And yet here we have a Burgess Cambrian,
0:18:58 > 0:19:00and there's the same trilobite, the hard parts,
0:19:00 > 0:19:04the shell which is all you normally get - but, in addition, limbs.
0:19:04 > 0:19:08Exactly yes. This is what sets the Burgess Shale apart
0:19:08 > 0:19:10from virtually all other Cambrian sites,
0:19:10 > 0:19:13or it certainly did at the time of its discovery,
0:19:13 > 0:19:18is that there are parts of animals, including trilobites, that preserve
0:19:18 > 0:19:21not only the hard shelly bits but the soft parts of the anatomy.
0:19:21 > 0:19:25So on this I can see antennae.
0:19:25 > 0:19:28Yes, and at the front of the animal there are a pair of limbs,
0:19:28 > 0:19:31but they're modified as antennae, so there's this pair
0:19:31 > 0:19:34of feeler-like structures that come out the front end of the trilobite,
0:19:34 > 0:19:39just like many modern arthropods that have that same set of structures of the front end.
0:19:39 > 0:19:42But there's something rather special about this particular trilobite?
0:19:42 > 0:19:46This particular one has not only a pair of antennae extending out,
0:19:46 > 0:19:49the feelers from underneath the head shield,
0:19:49 > 0:19:51but there's also a pair of antennae that stick out
0:19:51 > 0:19:54the back end of the animal, identical, or more or less identical,
0:19:54 > 0:19:56to the ones at the front.
0:19:56 > 0:19:59And these are the cerci,
0:19:59 > 0:20:02or antennae form like appendages sticking out the back end,
0:20:02 > 0:20:04presumably allowed the animal to sense
0:20:04 > 0:20:06what was going on behind it as well as in front.
0:20:06 > 0:20:09Which could have been useful in a sea in which there were...
0:20:09 > 0:20:12- Large predators. - ..quite serious predators.
0:20:12 > 0:20:14Yes indeed, yes that's right.
0:20:35 > 0:20:38The first fossil Walcott described to science
0:20:38 > 0:20:41is still to be found in his quarry today.
0:20:43 > 0:20:47He named this little creature, Marrella.
0:20:47 > 0:20:49Walcott knew he hadn't found a trilobite
0:20:49 > 0:20:52but still tried to compare it with something familiar,
0:20:52 > 0:20:55in this case a shrimp-like crustacean.
0:21:02 > 0:21:05I've got before me the lace crab.
0:21:05 > 0:21:08It's preserved as a kind of silvery sheen
0:21:08 > 0:21:10on the surface of the shale.
0:21:11 > 0:21:15It's an exquisite little thing. It's no bigger than a small coin.
0:21:15 > 0:21:18One of the things that Walcott noticed immediately
0:21:18 > 0:21:20was that it had segmented limbs...
0:21:21 > 0:21:23..which meant it was an arthropod.
0:21:23 > 0:21:27It was an early member of that great group that includes crabs
0:21:27 > 0:21:29and lobsters and insects and spiders today.
0:21:31 > 0:21:35'In fact, Walcott had not unearthed a relative of the trilobites
0:21:35 > 0:21:37or even another crustacean,
0:21:37 > 0:21:40but a different kind of arthropod altogether.
0:21:41 > 0:21:44But in the pursuit of trying to convince a sceptical world,
0:21:44 > 0:21:49he added artistic skills to his paleontological flair.
0:21:51 > 0:21:55This is the first scientific description of the lace crab
0:21:55 > 0:21:58in a publication of the Smithsonian Institution.
0:22:00 > 0:22:02They themselves are almost works of art.
0:22:04 > 0:22:07And to a certain extent works of artifice as well,
0:22:07 > 0:22:10because Walcott took photographs and then retouched them very,
0:22:10 > 0:22:13very carefully to make the limbs more obvious.
0:22:15 > 0:22:19They were generally very, very honest interpretations,
0:22:19 > 0:22:23but it is art slightly improving upon nature,
0:22:23 > 0:22:27and subsequent work showed where his errors were
0:22:27 > 0:22:30and where art had perhaps exceeded fact.
0:22:31 > 0:22:33But nonetheless, they still remain
0:22:33 > 0:22:36a pleasure to look at after all these years.
0:22:42 > 0:22:46It took Walcott three years to publish his account of Marrella
0:22:46 > 0:22:49and his carefully retouched photographs
0:22:49 > 0:22:51subtly emphasised crustacean features.
0:22:54 > 0:22:57One of the things that held him back was the apparently different
0:22:57 > 0:23:00appearance of the fossils of Marrella.
0:23:03 > 0:23:07Walcott later realised that this was a clue to the calamity
0:23:07 > 0:23:11that had miraculously preserved these soft bodied creatures.
0:23:15 > 0:23:19In search of the unusual event that created the Burgess Shale,
0:23:19 > 0:23:22I have come to University College, Dublin.
0:23:27 > 0:23:31Here, Dr Paddy Orr studies the geochemical processes
0:23:31 > 0:23:34of decay and preservation, called taphonomy.
0:23:36 > 0:23:38He's going to show me why being buried alive
0:23:38 > 0:23:40was key to their preservation.
0:23:42 > 0:23:46Well, it's an arthropod like many Burgess Shale fossils.
0:23:46 > 0:23:50- And it's Artemia, the brine shrimp.- Yeah.
0:23:50 > 0:23:52Sometimes called a sea monkey.
0:23:52 > 0:23:55- And this is one that's just died. - That was two days.
0:23:55 > 0:23:57- Two days.- Two days after death, yeah.
0:23:57 > 0:24:00- And at this stage I can see it's all nicely filled out.- Yeah.
0:24:00 > 0:24:03- You can see the limbs along here. - Yeah.
0:24:03 > 0:24:05- You can see the eyes, even the antennae.- Exactly.
0:24:05 > 0:24:08And you can see the flesh all the way along
0:24:08 > 0:24:11each of the antennae and the appendages on the trunk,
0:24:11 > 0:24:14and they're all neatly lined up in a steady row after each other.
0:24:15 > 0:24:19- Well, what happens when you allow time to take its course?- OK.
0:24:21 > 0:24:27So, these have been decaying for two weeks now, yeah.
0:24:27 > 0:24:32- Oh, goodness me, yes. - It's miserable looking, isn't it?
0:24:32 > 0:24:36The gut has completely disintegrated into a series of pieces
0:24:36 > 0:24:38and you see the way all the flesh inside the cuticle
0:24:38 > 0:24:40has essentially shrivelled up...
0:24:40 > 0:24:42- Turned to a mush. - ..mushed up, exactly.
0:24:42 > 0:24:45And all the appendages themselves are now all spread out...
0:24:45 > 0:24:48- On either side. - ..collapsed onto the surface, yeah.
0:24:48 > 0:24:51- It's flattened?- Exactly, and that tells us a very important point,
0:24:51 > 0:24:55which is these are all coming to rest in their most stable orientation.
0:24:55 > 0:24:58They're collapsing down onto the surface.
0:24:58 > 0:25:02So, if you had a situation where, inside a bed,
0:25:02 > 0:25:04the animals were in all sorts of different orientations,
0:25:04 > 0:25:07it's a sign they haven't settled down to the surface,
0:25:07 > 0:25:10they've been carried along in some sort of event bed
0:25:10 > 0:25:13and buried rapidly in all sorts of higgledy-piggledy orientations.
0:25:22 > 0:25:25The apparently random orientation of fossils
0:25:25 > 0:25:28suggests the creatures of the Burgess Shale
0:25:28 > 0:25:31were engulfed by undersea landslides,
0:25:31 > 0:25:33possibly triggered by earthquakes.
0:25:37 > 0:25:40If they had not been preserved at the moment of death,
0:25:40 > 0:25:44just a few weeks later there would have been nothing left of them.
0:25:50 > 0:25:55Well, let's run time on a little bit further and see...
0:25:55 > 0:25:58- OK. So that's three weeks. - Oh, my goodness!
0:25:58 > 0:26:01- That looks like brine shrimp soup to me.- Yes, it's not far off.
0:26:01 > 0:26:03It is absolutely right.
0:26:03 > 0:26:05Put it under the microscope and we'll see
0:26:05 > 0:26:08if we get any sort of detail out of it at all.
0:26:11 > 0:26:15- Oh, yeah, there's a few... - There we are.- ..little wisps.
0:26:15 > 0:26:18- The preservation window has now gone away.- Exactly.
0:26:18 > 0:26:21Look how little time it took to do that.
0:26:21 > 0:26:24Three weeks at a constant temperature. It's amazing, isn't it?
0:26:24 > 0:26:27So that shows what a miracle the Burgess Shale really is.
0:26:27 > 0:26:29Absolutely, absolutely.
0:26:37 > 0:26:39Often accompanied by his family,
0:26:39 > 0:26:42Walcott continued excavating the Burgess Shale
0:26:42 > 0:26:44until he was 74 years old.
0:26:47 > 0:26:51He had proved the Cambrian seas were thronging with life.
0:26:55 > 0:26:58But the sheer number of specimens Walcott discovered,
0:26:58 > 0:27:01some 65,000 in all,
0:27:01 > 0:27:03meant few questioned his efforts to relate them
0:27:03 > 0:27:06to animals already known to science.
0:27:08 > 0:27:11A case in point is Anomalocaris.
0:27:14 > 0:27:17This is a detective story and the story starts,
0:27:17 > 0:27:19like all good stories, with a clue.
0:27:21 > 0:27:25When the Canadian Pacific Railway was pushed through the Rockies,
0:27:25 > 0:27:27a fossil was discovered.
0:27:28 > 0:27:30It was called Anomalocaris,
0:27:30 > 0:27:33meaning something like anomalous or strange shrimp.
0:27:33 > 0:27:37And Walcott thought it was something to do with the arthropods,
0:27:37 > 0:27:40those animals with jointed legs.
0:27:40 > 0:27:44Could this be the leg of a very large arthropod?
0:27:46 > 0:27:48But nobody really knew what it was.
0:27:50 > 0:27:53Walcott, of course, named lots of other fossils
0:27:53 > 0:27:55from the Walcott quarry.
0:27:55 > 0:27:59And this is the second clue in the story.
0:28:00 > 0:28:02Which he called Peytoia.
0:28:02 > 0:28:05It's a strange kind of rather large round object.
0:28:05 > 0:28:08You can see why it might be thought to be a jellyfish
0:28:08 > 0:28:12because it's got radial symmetry and lots of creases running around it,
0:28:12 > 0:28:16and a sort of ziggy zaggy hole in the middle.
0:28:18 > 0:28:21There was even a third one.
0:28:21 > 0:28:23It's called Laggania.
0:28:23 > 0:28:26A sort of flappy, rather indefinite, flappy looking thing.
0:28:26 > 0:28:30And so the story remained for many years
0:28:30 > 0:28:33until the specimens were re-studied.
0:28:49 > 0:28:52It wasn't until 1966, long after Walcott's death,
0:28:52 > 0:28:57that a team led by Professor Harry Whittington of Cambridge University
0:28:57 > 0:29:00began to re-examine the Burgess Shale fossils.
0:29:04 > 0:29:07And what they found would turn our understanding
0:29:07 > 0:29:09of the Cambrian world on its head.
0:29:11 > 0:29:14By looking at the fossils with fresh eyes
0:29:14 > 0:29:18they were able to make unexpected connections Walcott had missed.
0:29:23 > 0:29:27And one of the first things they found was that Anomalocaris,
0:29:27 > 0:29:31Peytoia and Laggania were not, in fact, separate creatures at all.
0:29:34 > 0:29:38Now, even in palaeontology you have the equivalent of a Rosetta Stone,
0:29:38 > 0:29:40something that puts all things together
0:29:40 > 0:29:45and enabled you to translate and understand the meaning of a fossil.
0:29:46 > 0:29:49And so it was with this particular collection.
0:29:49 > 0:29:53My old prof, Harry Whittington, and his student,
0:29:53 > 0:29:56Derek Briggs, made the discovery.
0:29:56 > 0:29:59They found, on one and the same specimen,
0:29:59 > 0:30:05they found the Peytoia, the jellyfish mouthparts,
0:30:05 > 0:30:11the limb, as it now was, and at the back end, the third element.
0:30:12 > 0:30:15It was discovered that they actually
0:30:15 > 0:30:19all belonged to one very large fossil.
0:30:21 > 0:30:24But if we really want to see what this animal looked like...
0:30:28 > 0:30:33..we need to bring it back to life by gently...
0:30:35 > 0:30:38..putting some water on the specimen like this.
0:30:41 > 0:30:43And there, emerging from the rock...
0:30:46 > 0:30:51..the body, the great appendages, they are,
0:30:51 > 0:30:56great graspers at the front reveal what a huge animal this was.
0:30:58 > 0:31:03It was the top of the Cambrian food chain, a predator.
0:31:04 > 0:31:10In its own way as remarkable as Tyrannosaurus Rex.
0:31:10 > 0:31:12What a creature!
0:31:19 > 0:31:23'Anomalocaris Canadensis was the alpha predator in its day.
0:31:24 > 0:31:29'Still more than 250 million years before the dinosaurs.'
0:31:35 > 0:31:39The realisation that three separate creatures were all parts
0:31:39 > 0:31:43of one large predator helped change how the Cambridge team
0:31:43 > 0:31:46looked at the creatures of the Burgess Shale.
0:31:47 > 0:31:51Suddenly they weren't looking for relatives of trilobites
0:31:51 > 0:31:53or other known animals,
0:31:53 > 0:31:56they were looking at a lost world of designs for living
0:31:56 > 0:31:59previously unknown to science.
0:32:01 > 0:32:04Recreated here at several times their actual size,
0:32:04 > 0:32:07together they became known as Weird Wonders.
0:32:08 > 0:32:11Among the many animals of the Burgess Shales,
0:32:11 > 0:32:14there are one or two undoubted Weird Wonders,
0:32:14 > 0:32:18and one of the weirdest of all, no bigger than a shrimp, Opabinia.
0:32:19 > 0:32:23You see the blobs there at the front, those are the eyes,
0:32:23 > 0:32:25no fewer than five eyes.
0:32:27 > 0:32:31And at the front it has a great appendage that stretches out...
0:32:33 > 0:32:35..rather like an elephant's trunk,
0:32:35 > 0:32:38and seems to have a grasping organ at the front.
0:32:38 > 0:32:40So on this wonderful specimen,
0:32:40 > 0:32:44the trunk appendage is thrown back over its shoulder really,
0:32:44 > 0:32:49and along the side of the body a series of flaps, presumably used for
0:32:49 > 0:32:52propelling the animal through the water, so it looks like a predator.
0:32:52 > 0:32:54Of course it excited much debate
0:32:54 > 0:32:56about where it fitted
0:32:56 > 0:32:58into the animal kingdom.
0:32:58 > 0:33:01But whatever the answer is, this remains one of the most
0:33:01 > 0:33:05extraordinary and exciting animals from the Burgess Shale.
0:33:08 > 0:33:12This new world of bewildering creatures, all existing at a time
0:33:12 > 0:33:17previously thought to be dominated only by a handful of animals,
0:33:17 > 0:33:21provoked much hard thinking in the scientific community.
0:33:25 > 0:33:28One iconoclastic palaeontologist and best selling writer,
0:33:28 > 0:33:33Stephen Jay Gould, seized upon the findings and controversially
0:33:33 > 0:33:37argued they required a wholesale reassessment of evolutionary theory.
0:33:42 > 0:33:43If Gould was right
0:33:43 > 0:33:47and the Cambrian period explosively threw up new designs...
0:33:49 > 0:33:50..what could have triggered it?
0:34:05 > 0:34:08The Cambrian explosion has since been explained
0:34:08 > 0:34:13in a myriad of ways, from tectonic shifts to changes in DNA.
0:34:15 > 0:34:18But two of the most convincing theories are based on
0:34:18 > 0:34:21what can be thought of as small physical changes which had
0:34:21 > 0:34:24a massive knock-on evolutionary effect.
0:34:32 > 0:34:35My first stop is the British Optical Association
0:34:35 > 0:34:38and a tiny private museum
0:34:38 > 0:34:41that contains lenses of every conceivable type.
0:34:43 > 0:34:47Here, Dr Andrew Parker of the Natural History Museum,
0:34:47 > 0:34:50tries to convince me he has solved the mystery.
0:34:53 > 0:34:56What brought you particularly to be interested
0:34:56 > 0:34:58in this particular problem?
0:34:58 > 0:35:01It was looking at vision today, looking at eyes
0:35:01 > 0:35:02and looking at colour,
0:35:02 > 0:35:06and how far we could actually take that back through time.
0:35:06 > 0:35:10We can see that there are eyes through the fossil record.
0:35:10 > 0:35:12So I began to look at where was the first of those.
0:35:12 > 0:35:16And that took me right back to somewhere in the early Cambrian,
0:35:16 > 0:35:18to the very first trilobites.
0:35:18 > 0:35:21Well, of course we've got the trilobite here, this is
0:35:21 > 0:35:24a 400 million year old one
0:35:24 > 0:35:27and this shows the lenses on the eyes particularly well.
0:35:29 > 0:35:32Well, of course trilobite eyes are compound eyes,
0:35:32 > 0:35:34that is they're composed of many lenses,
0:35:34 > 0:35:37so they see the world in a slightly different way.
0:35:37 > 0:35:39I mean this toy...
0:35:39 > 0:35:41gives me lots and lots of different images.
0:35:42 > 0:35:46Each facet of the compound eye would have seen its own particular segment
0:35:46 > 0:35:49of the environment, and those segments would have been
0:35:49 > 0:35:53added together to form an image through a number of pixels.
0:35:53 > 0:35:58It's only when that lens evolved they have a whole image to decipher.
0:35:58 > 0:36:01Whereas previously it was just shades of light and dark.
0:36:05 > 0:36:09Before the evolution of complex lenses, some creatures had
0:36:09 > 0:36:13eyelike organs that could detect the difference between light and dark.
0:36:14 > 0:36:18But the ability to see shape and depth was revolutionary.
0:36:21 > 0:36:23So there was a time, what shall we say,
0:36:23 > 0:36:28a time almost of darkness, and then suddenly
0:36:28 > 0:36:31they could see the world and other things in the world could see them?
0:36:31 > 0:36:35Certainly an image was formed on their retina and they could see
0:36:35 > 0:36:38the animals around them and pinpoint them with accuracy.
0:36:39 > 0:36:43It could see all the other animals as basically chunks of protein
0:36:43 > 0:36:44waiting to be eaten.
0:36:44 > 0:36:47Well, of course the lumps of protein also would benefit from having eyes
0:36:47 > 0:36:49in order to run away.
0:36:49 > 0:36:51Absolutely, so this triggered a visual arms race,
0:36:51 > 0:36:55but basically the behaviour of animals were totally changing.
0:36:55 > 0:36:58It was becoming more similar to the system of animals today.
0:36:58 > 0:37:03So you would believe that the sight, the evolution of sight,
0:37:03 > 0:37:08complex sight, was the crucial spark that provoked this tremendous burst
0:37:08 > 0:37:10of evolution at the base of the Cambrian?
0:37:10 > 0:37:14Yes, I do, and a part of that is based on how important vision is
0:37:14 > 0:37:18today and how it's perhaps the most powerful universal sense
0:37:18 > 0:37:19on earth now.
0:37:19 > 0:37:22So in a nutshell, the eyes have it.
0:37:28 > 0:37:32So, did the development of the eye, and the massive advantage it gave
0:37:32 > 0:37:36predators, suddenly accelerate the rise of creatures that
0:37:36 > 0:37:40could defend themselves, and lead to the demise of those who could not?
0:37:43 > 0:37:44Perhaps.
0:37:44 > 0:37:47But a development of another kind altogether might have changed
0:37:47 > 0:37:50the very fabric of the Cambrian Seas.
0:37:54 > 0:37:57What I have in front of me is a slab of Burgess Shale
0:37:57 > 0:38:00and it's covered in what looks like spaghetti.
0:38:00 > 0:38:03Well, it's not spaghetti, it's worms.
0:38:04 > 0:38:07But the term worm is itself rather meaningless.
0:38:07 > 0:38:12It covers a whole range of sort of soft squiggly things
0:38:12 > 0:38:14that are zoologically speaking only very loosely related.
0:38:16 > 0:38:20There are bristle worms, there are acorn worms, there are penis worms,
0:38:20 > 0:38:23there are even worms that look like the ones you dig up
0:38:23 > 0:38:24in your garden,
0:38:24 > 0:38:27doing different jobs in the Burgess Shale sea,
0:38:27 > 0:38:30some of them burrowing, some of them eating sediment.
0:38:30 > 0:38:33They were a very, very important part of the ecology,
0:38:33 > 0:38:37and some people believe that they may be even the reason
0:38:37 > 0:38:39for the Cambrian explosion itself.
0:38:46 > 0:38:50My next potential answer to what triggered the Cambrian explosion
0:38:50 > 0:38:53takes me back to the coast of ancient Cambria to meet
0:38:53 > 0:38:56Dr Martin Brasier of Oxford University.
0:38:58 > 0:39:04His surprising solution to the puzzle takes guts - lots of them.
0:39:04 > 0:39:11Well, Martin, I can see on the shore here a lot of green slime or scum.
0:39:12 > 0:39:14Er, yes this is formed by phytoplankton.
0:39:14 > 0:39:18You can see that the hundreds of little cells have been caught
0:39:18 > 0:39:20to form bubbles that are blowing in the wind.
0:39:20 > 0:39:25So this is a very important lifestyle within the current
0:39:25 > 0:39:26marine habitat?
0:39:26 > 0:39:28It's absolutely fundamental to many of the things
0:39:28 > 0:39:30that are going on here, the sandy shore.
0:39:30 > 0:39:33Most of the food is coming from these algae,
0:39:33 > 0:39:35- this phytoplankton and just here in fact...- Ah!
0:39:35 > 0:39:40..we can see one of these creatures, in fact there are two here...
0:39:40 > 0:39:42- Oh, I can see them here. - ..just emerging from the sand.
0:39:42 > 0:39:45The worm is living inside the tube almost entirely made
0:39:45 > 0:39:47of tiny pieces of seashell.
0:39:49 > 0:39:52And waiting for this, for dinnertime to arrive
0:39:52 > 0:39:55and here it is, here's dinnertime coming out across the worms now.
0:39:59 > 0:40:02So here's a good example of a lugworm burrow here.
0:40:02 > 0:40:04Let's get down and have a look at it.
0:40:04 > 0:40:08And you can see this little depression here is where the worm
0:40:08 > 0:40:13takes the water and the sediment in, it's formed a great U-shaped
0:40:13 > 0:40:15burrow underneath.
0:40:15 > 0:40:19And there's a little worm called the lugworm sits at the bottom here,
0:40:19 > 0:40:22drawing the water in down here, and full of bacteria
0:40:22 > 0:40:26and organic matter and it actually uses its through gut,
0:40:26 > 0:40:30the digestive tract, and then it excretes it at the surface here.
0:40:30 > 0:40:32- It, er, extrudes it... - Extrudes it.
0:40:32 > 0:40:34- ..cos it comes out as a kind of pipe, doesn't it?- Yes.
0:40:36 > 0:40:40OK, you see the water being squeezed out here,
0:40:40 > 0:40:41I'm up to try and break it.
0:40:43 > 0:40:45Oh...
0:40:45 > 0:40:47It looks like an earthquake.
0:40:47 > 0:40:48Er...
0:40:54 > 0:40:55Could be...
0:40:57 > 0:40:58It must be in here somewhere.
0:41:05 > 0:41:08There's a lot of hard work trying to find this elusive worm.
0:41:10 > 0:41:12Ah, what's that, something?
0:41:12 > 0:41:15Oh, here we are, this is the lugworm, er...
0:41:15 > 0:41:19and you can see the sort of staining from the food and the bacteria
0:41:19 > 0:41:24and it's contracted now to try and make us... Make it less of a target.
0:41:24 > 0:41:26- I think we ought to put it back, don't you?- There we go.
0:41:27 > 0:41:29And it looks happy.
0:41:35 > 0:41:37So come and see these rocks.
0:41:37 > 0:41:39Oh, yeah, I can see it looking quite promising
0:41:39 > 0:41:41just at the back of the beach.
0:41:41 > 0:41:43Mind the slippery weed.
0:41:46 > 0:41:49A great mass, er, of worm burrows, you can see...
0:41:49 > 0:41:52It's a sort of tubular mottling, isn't it?
0:41:52 > 0:41:56It is. Each of these represents the activity of an individual worm,
0:41:56 > 0:41:59burrowing through the sediment,
0:41:59 > 0:42:03and it's thought to be the activity of a worm forming a very shallow
0:42:03 > 0:42:06U-shaped burrow, moving the burrow up and down...
0:42:06 > 0:42:10- A little bit like a lugworm? - A little bit like the lugworm.
0:42:10 > 0:42:13So it's gradually turning the shallow marine environment
0:42:13 > 0:42:18into something like a soil, so they're making the whole surface
0:42:18 > 0:42:21of the planet much more habitable.
0:42:21 > 0:42:24Yes and er, I would have thought that their bringing
0:42:24 > 0:42:28the nutrients up to the surface and changing the way that the oxygen
0:42:28 > 0:42:30was moved down into the sediment,
0:42:30 > 0:42:34absolutely transformed the nature of the marine world at this time.
0:42:38 > 0:42:42The development of the gut and the growth of a worm population
0:42:42 > 0:42:47extended the food chain into a new dimension - into the sea floor.
0:42:52 > 0:42:56In turn, this helped change the chemistry of the seas,
0:42:56 > 0:43:01creating opportunities for new species to thrive and, just maybe,
0:43:01 > 0:43:04stimulating fast evolution.
0:43:04 > 0:43:08Have you looked at any of the Burgess Shale...?
0:43:12 > 0:43:15A recently discovered Weird Wonder
0:43:15 > 0:43:18helps support just how important the evolution of the gut was.
0:43:20 > 0:43:24Lorna O'Brien of the University of Toronto talks me through
0:43:24 > 0:43:28a creature commonly known as the Tulip animal.
0:43:29 > 0:43:34Well, Lorna, the first thing to say is the Tulip animal,
0:43:34 > 0:43:36well, why isn't it a plant?
0:43:36 > 0:43:41It certainly looks very much like a plant, but it has features
0:43:41 > 0:43:46that lead us to believe that it has a stomach and a digestive tract.
0:43:46 > 0:43:49How is it actually put together then, this remarkable animal?
0:43:49 > 0:43:53So these are probably active filter feeders, so unlike many filter
0:43:53 > 0:43:57feeders that passively wait for water to pass over them to capture
0:43:57 > 0:44:00the food, these were probably actively pumping from
0:44:00 > 0:44:03- the base of it. - Oh, they suck water in?
0:44:03 > 0:44:07Yes, so we have one specimen which is beautifully preserved,
0:44:07 > 0:44:11actually the cross section of the base of the animal,
0:44:11 > 0:44:13and that shows six holes.
0:44:13 > 0:44:17And there was also another hole right at the top of the animal
0:44:17 > 0:44:23which is interpreted as the anus, so where the food particles are excreted
0:44:23 > 0:44:26once it has passed through the stomach and the digestive canal.
0:44:26 > 0:44:29So if I used the term, Weird Wonder,
0:44:29 > 0:44:33- I might actually be accurate.- Yes.
0:44:33 > 0:44:35I think definitely we could call these a Weird Wonder.
0:44:35 > 0:44:38We have nothing else like these at the Burgess Shale
0:44:38 > 0:44:40or in any deposit worldwide.
0:44:40 > 0:44:42And how big does it grow?
0:44:42 > 0:44:45They're actually one of the larger Burgess Shale animals, so...
0:44:45 > 0:44:48Oh, my goodness, it looks like a golf club there,
0:44:48 > 0:44:51- doesn't it, somewhat?- Yes, so this specimen here is 25cm in length
0:44:51 > 0:44:54and this is actually one of the largest Burgess Shale animals
0:44:54 > 0:44:56or specimens that you will find.
0:45:00 > 0:45:02But we also have ones that are
0:45:02 > 0:45:07no more than a centimetre or 15mm in length.
0:45:10 > 0:45:14And the Tulip animals often grew and reproduced in large groups.
0:45:17 > 0:45:21So we may not have a plant here
0:45:21 > 0:45:24- but we may have one of the earliest gardens?- Yes.
0:45:24 > 0:45:26And a stunning garden at that.
0:45:40 > 0:45:43So, in the final analysis,
0:45:43 > 0:45:47what triggered the explosion of life in the Cambrian seas?
0:45:48 > 0:45:52Was it a change in the levels of oxygen in the atmosphere
0:45:52 > 0:45:54or chemistry in the ocean?
0:45:54 > 0:45:58Was it perhaps the appearance of animals with sight?
0:45:58 > 0:46:01Or was it the activities of burrowing worms?
0:46:01 > 0:46:05Or maybe, at a fundamental level, a change in the genome?
0:46:05 > 0:46:10Perhaps we'll never know, but what we do know is that the Cambrian
0:46:10 > 0:46:14evolutionary explosion changed the course of life on earth forever.
0:46:20 > 0:46:24By the late 1980s many scientists agreed with Gould that the
0:46:24 > 0:46:28Burgess Shale proved the reality of the Cambrian evolutionary explosion.
0:46:30 > 0:46:33But questions remained about many of the creatures themselves
0:46:33 > 0:46:36and their relationship to known animals.
0:46:49 > 0:46:53By now responsibility for excavating at the site had passed
0:46:53 > 0:46:58from Whittington's Cambridge group to a new Canadian team
0:46:58 > 0:47:03led by Dr Desmond Collins of the Royal Ontario Museum, or ROM.
0:47:08 > 0:47:12The scale and scope of the ROM's fieldwork dwarfed anything
0:47:12 > 0:47:14that had gone before it...
0:47:15 > 0:47:17..extending the site several times over
0:47:17 > 0:47:21and amassing 150,000 new specimens.
0:47:26 > 0:47:30And helping the team of professional palaeontologists were fresh-faced
0:47:30 > 0:47:34volunteers, including a young Frenchman called Jean Bernard Caron,
0:47:34 > 0:47:37who would later take over as expedition leader.
0:47:46 > 0:47:51Ah, so here we are at the largest hole...
0:47:51 > 0:47:54the one below the Walcott level.
0:47:54 > 0:47:57Yeah, actually, we are standing here about 5m below
0:47:57 > 0:47:59the original floor of the Walcott quarry.
0:47:59 > 0:48:02This is older strata, newer strata up above us.
0:48:02 > 0:48:06And as you can see there's a lot of drill marks here, there were...
0:48:06 > 0:48:14By 2013 the number of identified species had risen to more than 200.
0:48:18 > 0:48:22And using pioneering techniques, the ROM has been able to analyse
0:48:22 > 0:48:26the Burgess fossils in more detail than ever before,
0:48:26 > 0:48:28with revealing results.
0:48:31 > 0:48:35This method using polarising photography achieves
0:48:35 > 0:48:39the sort of clarity only seen before with Walcott's famous,
0:48:39 > 0:48:42if slightly dubious, touched up photographs.
0:48:46 > 0:48:48Such techniques have enriched our understanding
0:48:48 > 0:48:51of the Burgess Shale's Weird Wonders.
0:48:56 > 0:49:00And recently the discovery of other Burgess Shale-like sites
0:49:00 > 0:49:05around the world has proved that the same marine fauna was widespread.
0:49:06 > 0:49:08They confirmed the Cambrian explosion
0:49:08 > 0:49:11because they include creatures comparable to those
0:49:11 > 0:49:13of the Burgess Shale.
0:49:14 > 0:49:17Some of the sites even help elucidate longstanding
0:49:17 > 0:49:19Burgess enigmas.
0:49:23 > 0:49:26As a result, many scientists now conclude that
0:49:26 > 0:49:31some of the famous Weird Wonders might not be so weird after all.
0:49:40 > 0:49:44I well remember when this animal was unveiled to the scientific public.
0:49:44 > 0:49:46Everybody laughed.
0:49:51 > 0:49:55It was the weirdest of the Weird Wonders.
0:49:55 > 0:50:00An animal called, Hallucigenia, as if it always belonged
0:50:00 > 0:50:02in the realm of the imagination.
0:50:02 > 0:50:06And then, of course, it defied classification
0:50:06 > 0:50:11and this animal was shown wandering around on spindly little spines
0:50:11 > 0:50:15with these strange organs on the back,
0:50:15 > 0:50:17feeding organs originally.
0:50:17 > 0:50:20That's right, the food was thought to be transported
0:50:20 > 0:50:23from one of these tentacles to the head.
0:50:25 > 0:50:27But we now know that was all wrong.
0:50:27 > 0:50:28It was wrong indeed,
0:50:28 > 0:50:33and the scientists discover a second row of structures like these ones
0:50:33 > 0:50:38here, with small spines at the ends, so now it was not just
0:50:38 > 0:50:43a single row, but two rows, and those structures were interpreted as legs.
0:50:43 > 0:50:49So in fact another row of these was found by excavating
0:50:49 > 0:50:51on the original fossils,
0:50:51 > 0:50:55and these became legs, so the animal...
0:50:55 > 0:50:57was turned over.
0:50:57 > 0:51:02That's right. The head and the back are still quite puzzling today.
0:51:02 > 0:51:05- You still don't know which is front and back?- No.
0:51:06 > 0:51:11So upside down certainly, and back to front possibly?
0:51:11 > 0:51:16That's correct. We still don't understand it very clearly.
0:51:16 > 0:51:20So this model is more than life-size.
0:51:20 > 0:51:21This is one of our specimens.
0:51:22 > 0:51:24- Is that all? - That's it.
0:51:27 > 0:51:29Ah, but under the microscope
0:51:29 > 0:51:33it reveals wondrous details.
0:51:33 > 0:51:36Absolutely, in fact it turns out that these spines are preserved
0:51:36 > 0:51:39in other fossil deposits all across the world,
0:51:39 > 0:51:43and so therefore we now understand this animal to have a much bigger
0:51:43 > 0:51:45family tree than previously thought.
0:51:51 > 0:51:56Today Hallucigenia's distant relatives live not in the sea,
0:51:56 > 0:51:57but on land.
0:51:58 > 0:52:03Like this charming velvet worm from the tropical forests of Australasia.
0:52:10 > 0:52:13It seems Walcott's attempt to make the Burgess fossils relate to
0:52:13 > 0:52:18known animals might not have been completely misguided after all.
0:52:21 > 0:52:25No matter how weird or wonderful these Burgess animals might seem,
0:52:25 > 0:52:29we now know that they are related to animals still living today.
0:52:35 > 0:52:37A list that includes species
0:52:37 > 0:52:39as varied as squid, starfish,
0:52:39 > 0:52:41scorpions and even
0:52:41 > 0:52:43backboned animals like ourselves.
0:52:49 > 0:52:52Not all of the new discoveries are ancient fossils.
0:52:53 > 0:52:54And Jean Bernard shows me
0:52:54 > 0:52:58some of the more unusual treasures that have been found near the site.
0:53:00 > 0:53:04Well, there's more history in the Walcott quarry,
0:53:04 > 0:53:07the history of the great man himself.
0:53:07 > 0:53:10That's right. All this memorabilia were collected by
0:53:10 > 0:53:14the Royal Ontario Museum expeditions, and they found this glove here
0:53:14 > 0:53:20which is a small glove and probably belonging to Helen Walcott.
0:53:20 > 0:53:24Oh, so, the expedition was a family affair.
0:53:24 > 0:53:29It was indeed. So Walcott took his wife and children
0:53:29 > 0:53:34to the quarries and they all participated in finding fossils.
0:53:34 > 0:53:38But here is a remarkable example of an artefact found in the quarry,
0:53:38 > 0:53:45and that was found in a block of ice in 1995, and...
0:53:45 > 0:53:49Oh, goodness, and a picture of Teddy Roosevelt on the front.
0:53:49 > 0:53:53So, when, when we find this, we can deduct that Walcott was actually
0:53:53 > 0:53:56using this newspaper to pack fossils,
0:53:56 > 0:53:58not just to read the news there, it would be...
0:53:58 > 0:54:00No, no, no, so it's... Well, some things never change,
0:54:00 > 0:54:04we still use high quality newspapers to wrap fossils today.
0:54:04 > 0:54:09Absolutely. The beauty with this is you know what Walcott
0:54:09 > 0:54:12was doing and what he was eating as well.
0:54:12 > 0:54:16Pure shamrock lard, it says.
0:54:16 > 0:54:20In National Parks the rules are that you have to leave the camp
0:54:20 > 0:54:23as you, you found it, so clean and pristine.
0:54:23 > 0:54:28But at the time that was not the case, so Walcott left, you know,
0:54:28 > 0:54:32all these piles of teapots and cans and so on and so forth.
0:54:32 > 0:54:34Well, I'm rather glad he did.
0:54:34 > 0:54:37It's given us more history that we wouldn't otherwise have had.
0:54:37 > 0:54:38Absolutely.
0:54:48 > 0:54:53It's a profound and rather edifying thought that many of the creatures
0:54:53 > 0:54:57that still swim in Pembrokeshire's rock pools owe their existence
0:54:57 > 0:55:01to the unusual creatures first discovered half a world away.
0:55:11 > 0:55:15Perhaps a good place to summarise our continuing connection
0:55:15 > 0:55:17with this ancient Cambrian past,
0:55:17 > 0:55:22can also be found on the menu of the local beach's snack bar.
0:55:24 > 0:55:28This might be the perfect spot for my Burgess buffet.
0:55:32 > 0:55:33Hello.
0:55:33 > 0:55:38Have you got per chance some arthropods, like crustaceans
0:55:38 > 0:55:44will do, maybe some molluscs and some famous Welsh laverbread?
0:55:44 > 0:55:46Yeah, yeah, we've got all three. You're in luck.
0:55:46 > 0:55:51Well, that would be a truly Cambrian repast.
0:55:51 > 0:55:53And I've actually got cooking here a little bit of lobster
0:55:53 > 0:55:55- and some spider crab. - Oh, well, that'll do just fine.
0:55:55 > 0:55:58- All fresh, just off the beach here. - Oh, lovely.
0:56:01 > 0:56:03Right.
0:56:05 > 0:56:08The seaweed of course, laver, has been around since before
0:56:08 > 0:56:11the Cambrian, and we can trace back
0:56:11 > 0:56:17the arthropods and the molluscs to the same time.
0:56:17 > 0:56:18There you go.
0:56:18 > 0:56:20Oh, well, so it's a small diet perhaps,
0:56:20 > 0:56:23but might be a tasty one, let's have a go.
0:56:26 > 0:56:28Mmm, delicious.
0:56:32 > 0:56:35Well, I suppose I ought to try the mollusc as well.
0:56:35 > 0:56:36There you are, there we go.
0:56:40 > 0:56:45Well, it's a wonderful thing to think of all of these organisms
0:56:45 > 0:56:48still being found just off the Cambrian coast.
0:56:50 > 0:56:51Delicious.
0:57:06 > 0:57:11Today, more than a century after Charles Doolittle Walcott
0:57:11 > 0:57:13first set out from Field,
0:57:13 > 0:57:18it is difficult to appreciate just how brave and lucky he was when
0:57:18 > 0:57:22he ventured into the wild peaks of the Rocky Mountains to find fossils.
0:57:27 > 0:57:31The site he found made scientific history,
0:57:31 > 0:57:35revealing the full experimental complexity of early animal life
0:57:35 > 0:57:38for the first time,
0:57:38 > 0:57:39and helping to change
0:57:39 > 0:57:42and deepen our understanding of how evolution works.
0:57:49 > 0:57:53These tiny, beautifully preserved, soft bodied creatures recall
0:57:53 > 0:57:56a time when our planet was still a water world.
0:57:58 > 0:58:02When animals were still a set of fully functioning prototypes,
0:58:02 > 0:58:08while we humans were an experiment still more than 500 million years
0:58:08 > 0:58:09in the future.
0:58:13 > 0:58:18In the next episode, I venture forth into the arid North of China,
0:58:18 > 0:58:23in search of more miraculous fossils from a hidden period of evolution.
0:58:23 > 0:58:26It's the oldest known feathered dinosaur.
0:58:28 > 0:58:31A lost world where dinosaurs sprouted feathers
0:58:31 > 0:58:34and evolved into the first true birds.