0:00:05 > 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 part if you like,
0:00:15 > 0:00:19feathers, guts and many kinds of organisms that are soft-bodied,
0:00:19 > 0:00:25leave no trace behind, except in a few very special places.
0:00:25 > 0:00:28And it is to these places that we are going to
0:00:28 > 0:00:31travel in search of windows into the past.
0:00:33 > 0:00:39So far in this series we've been 8000 feet up in the Rocky Mountains to discover the fossilised
0:00:39 > 0:00:42remains of the earliest complex life in the seas.
0:00:47 > 0:00:51And travelled to China to see the newly discovered feathered dinosaurs
0:00:51 > 0:00:55that are revolutionising our understanding of the origin of birds.
0:00:58 > 0:01:02Now in this final episode, I'm heading to the heart of Europe
0:01:02 > 0:01:06in search of a lost world from 50 million years ago.
0:01:17 > 0:01:22This site in central Germany opens a window back in time
0:01:22 > 0:01:25to a strange, yet oddly familiar world.
0:01:26 > 0:01:29A site of special preservation
0:01:29 > 0:01:32that demands unorthodox techniques of excavation.
0:01:32 > 0:01:34And...
0:01:34 > 0:01:37reveals the extraordinary story of the early mammals.
0:01:42 > 0:01:46The area behind me was once a huge lake in the middle
0:01:46 > 0:01:50of a rainforest, through which wondered little horses,
0:01:50 > 0:01:53not much bigger than a cat, early predators,
0:01:53 > 0:01:55relatives of the living hedgehogs
0:01:55 > 0:01:59and maybe even our own earliest ancestor.
0:02:10 > 0:02:1465 million years ago, the dinosaurs disappeared from the world forever.
0:02:16 > 0:02:20But it wasn't a simple tale of the takeover by mammals,
0:02:20 > 0:02:23it was complicated and interesting.
0:02:24 > 0:02:29And to discover details to look into this early world of mammals and birds,
0:02:29 > 0:02:31we have to come to this pit of Messel, in Germany.
0:02:42 > 0:02:48The former quarry at Messel is one of the most remarkable fossil sites in the world,
0:02:48 > 0:02:51an entire ecosystem trapped in time
0:02:51 > 0:02:54with unparallel perfection of preservation.
0:02:57 > 0:03:01Most famous for its fossil mammals, many of them still covered in fur.
0:03:03 > 0:03:07Alongside them have been found the insects,
0:03:07 > 0:03:10plants and fish that many of them ate.
0:03:12 > 0:03:16And the reptiles and amphibians they sometimes competed with for food.
0:03:18 > 0:03:23As well as the birds and bats that flew above what was a lake now lost in time.
0:03:29 > 0:03:33First mined in the 18th and 19th centuries for brown coal,
0:03:33 > 0:03:38the rich oil shale later helped power the German industrial revolution.
0:03:43 > 0:03:46But, despite tantalising reports of fossils,
0:03:46 > 0:03:50intensive mining prevented any serious scientific excavation.
0:03:52 > 0:03:55When the machinery fell silent in the 1970s,
0:03:55 > 0:03:59the fossil hunters rushed in,
0:03:59 > 0:04:04and many paleontological riches hidden within the oily rock were revealed.
0:04:10 > 0:04:15This is the metal shale - it's black, very black.
0:04:15 > 0:04:18It's black because it's absolutely full of organic material.
0:04:19 > 0:04:23And the organic material, of course, is what gives rise to the
0:04:23 > 0:04:26oil for which this was commercially exploited.
0:04:27 > 0:04:31The rock is divided into terribly fine layers,
0:04:31 > 0:04:34sometimes less than a millimetre,
0:04:34 > 0:04:40and each one of those layers represents a season in a year called varves.
0:04:41 > 0:04:46But of course the rock also is famous for its fossils, and
0:04:46 > 0:04:51each one of these layers potentially could trap the remains of past life.
0:04:55 > 0:04:59Its softness also means it's possible to cut out great slabs
0:04:59 > 0:05:03of the shale rather like cutting up a giant chocolate brownie.
0:05:03 > 0:05:05CHAINSAW WHIRRS
0:05:13 > 0:05:17'With me, to explain the process is Dr Stephan Schaal, the site's director.'
0:05:18 > 0:05:21So they're taking the blocks out for today?
0:05:21 > 0:05:23Right, we are taking one, two blocks,
0:05:23 > 0:05:27one or two metres thick, er, with a chain saw and try to, to bring
0:05:27 > 0:05:31them up to the hill and cut them layer by layer looking for fossils.
0:05:31 > 0:05:34So that's all day's work from these two blocks here?
0:05:34 > 0:05:36This is, er, three or four blocks per day, yes.
0:05:42 > 0:05:48All together more than 100,000 fossils have been unearthed from the Messel pit.
0:05:48 > 0:05:52And up to several thousand more are discovered every digging season.
0:05:55 > 0:05:59Most are like this small fish, beautiful in their own right,
0:05:59 > 0:06:03though so numerous, their to science is not now newsworthy.
0:06:06 > 0:06:12But, once in a while new treasure is unearthed that has the potential to rewrite history.
0:06:15 > 0:06:19Such as the claims for Messel's most famous fossil mammal.
0:06:22 > 0:06:23I wonder what's in here.
0:06:23 > 0:06:26LAUGHTER
0:06:30 > 0:06:31Oh!
0:06:32 > 0:06:36This is the best fossil and rarest fossil of bird life.
0:06:36 > 0:06:37Yeah.
0:06:37 > 0:06:39- Ever seen from Messel. - Yeah, yeah.
0:06:39 > 0:06:46In 2009, after 26 years of being hidden from the world, an anonymous seller parted with
0:06:46 > 0:06:49the fossil known as Ida, for 1 million.
0:06:53 > 0:06:56Her skeleton is brilliantly preserved,
0:06:56 > 0:07:00possessing not just fossilised fur but even her last meal.
0:07:02 > 0:07:05The buyers, the Natural History Museum in Oslo,
0:07:05 > 0:07:09thought they'd spotted something that had been missed before -
0:07:09 > 0:07:13clear evidence of an advanced primate characteristic, an opposable thumb.
0:07:21 > 0:07:25'The discovery was claimed as revolutionary and it was
0:07:25 > 0:07:31'proposed that Ida was our oldest known ancestor, a missing link.
0:07:31 > 0:07:35'Dr Sandra Engels shows me two perfect replicas -
0:07:35 > 0:07:38'one for each side of Ida's body.'
0:07:38 > 0:07:41So both belong to the same individual
0:07:41 > 0:07:42but split in half.
0:07:44 > 0:07:48And in contrast to the other one, you can see the hands
0:07:48 > 0:07:51and the feet with opposable thumbs.
0:07:51 > 0:07:53- On both hands and feet? - On both hands and feet.
0:07:53 > 0:07:55- That's the sticky up one here. - This is true.
0:07:55 > 0:07:58You can see it very good on this foot here.
0:07:58 > 0:08:01And by this you can directly see it as a primate.
0:08:02 > 0:08:06And since it is so complete, one of the most complete
0:08:06 > 0:08:08primates in the world, er,
0:08:08 > 0:08:11it got very famous of course.
0:08:11 > 0:08:12Well, we can see its fur
0:08:12 > 0:08:16and we can see quite a lot about how the animal lived.
0:08:16 > 0:08:22Yes, typical for a primate is it has a bony ring around the eye socket,
0:08:22 > 0:08:26and we can see that the eyes look, as we call it rostrally,
0:08:26 > 0:08:31so it looks in front of it, as typical for primates...
0:08:31 > 0:08:34- Yes. - ..which is important for 3D vision.
0:08:34 > 0:08:36And these have pretty large eyes,
0:08:36 > 0:08:39so is that an indication they were nocturnal?
0:08:39 > 0:08:40Yes, it is.
0:08:40 > 0:08:42It is a nocturnal animal.
0:08:42 > 0:08:44Er, is this a broken bone?
0:08:44 > 0:08:49Yes, er, it's a broken wrist bone, but, erm,
0:08:49 > 0:08:52we can also see that it healed again.
0:08:52 > 0:08:56Erm, it happens often that primates fall off trees
0:08:56 > 0:08:58and break their wrist bones or legs.
0:08:58 > 0:09:01But what we can probably say for sure is that this primate,
0:09:01 > 0:09:04this perfect primate, fell off a tree that happened to be
0:09:04 > 0:09:08hanging over the water, so that it would fall down...
0:09:08 > 0:09:11- Sometime, sometime this happened. - ..into that preservation layer.
0:09:11 > 0:09:13This is why we have her now, this is true.
0:09:17 > 0:09:20Ida is definitely a primate,
0:09:20 > 0:09:23but whether she's our ancestor is still a matter of debate.
0:09:25 > 0:09:29'But rather than get caught up in arguments about evolution.
0:09:29 > 0:09:33'Dr Engels would like science to focus on Ida herself,
0:09:33 > 0:09:37'and the beautiful way she has been preserved.'
0:09:37 > 0:09:39It still is not clear where
0:09:39 > 0:09:43Ida or this whole group of early primate belongs to,
0:09:43 > 0:09:48but I think now it's time to look at the completeness of the specimen
0:09:48 > 0:09:52and to analyse it in detail rather than being
0:09:52 > 0:09:56concerned about its evolution or where it belongs to in detail.
0:10:01 > 0:10:07'Produced from a micro CT scan is a computer model of Ida's skull.
0:10:07 > 0:10:10'It allows us to dissect her virtually,
0:10:10 > 0:10:13'and see previously hidden parts of her anatomy.'
0:10:13 > 0:10:18So you can see, here, the 3D surface model of all teeth.
0:10:18 > 0:10:24Each tooth takes about five days for one tooth in this case.
0:10:24 > 0:10:25That's an awful lot of work...
0:10:25 > 0:10:27- Yes, it is.- ..in that jaw.
0:10:27 > 0:10:33So this is of course only done for very unique fossils as Darwinius.
0:10:33 > 0:10:37So, er, now you've reconstructed the teeth, what's the next stage, you
0:10:37 > 0:10:39see how the teeth actually work together?
0:10:39 > 0:10:43We arranged the teeth in a functional way,
0:10:43 > 0:10:47so what we do, I can show you the newest results...
0:10:47 > 0:10:49- Oh!- I can present to you.
0:10:49 > 0:10:53And we have a special software programme
0:10:53 > 0:10:57and it can calculate on the basis of the surface of the teeth
0:10:57 > 0:10:59how they operated and worked together.
0:10:59 > 0:11:03So they're like a piece of machinery really for processing food?
0:11:03 > 0:11:06Yes, we let Ida chew again.
0:11:06 > 0:11:13We know when we look at the morphology at the teeth that it ate probably leaves, fruit, seeds.
0:11:13 > 0:11:18Er, so not ideally suited to being, for example, a carnivore?
0:11:18 > 0:11:19Not at all.
0:11:27 > 0:11:30Sometimes you can learn still more about fossils by studying
0:11:30 > 0:11:32their modern counterparts.
0:11:33 > 0:11:37'At Battersea Children's Zoo, Anita Halligan cares for creatures
0:11:37 > 0:11:40'bear a noticeable similarity to Ida.'
0:11:45 > 0:11:48Of course, not everything is preserved as a fossil.
0:11:50 > 0:11:53If you want to understand more about extinct animals,
0:11:53 > 0:11:57sometimes the best way is to come and look at their living relatives.
0:11:59 > 0:12:01In the wild or even in a zoo.
0:12:13 > 0:12:15Pst, pst, come on guys.
0:12:16 > 0:12:20- One of the things you notice is their wet noses.- Yes.
0:12:20 > 0:12:22Well of course one of the things that would never
0:12:22 > 0:12:24preserve in the fossil record is the wetness of a nose.
0:12:24 > 0:12:26No, it would be very difficult.
0:12:26 > 0:12:30But I guess the, the characters of the feet and the hands would
0:12:30 > 0:12:33- preserve because they're, they're visible in the bones.- Yeah.
0:12:33 > 0:12:37And what is it about the, the hands of these animals?
0:12:37 > 0:12:40They've got five, er, fingers, very similar to our hands, erm,
0:12:40 > 0:12:43but they don't have an opposable thumb, erm,
0:12:43 > 0:12:46and they have nails rather than claws.
0:12:46 > 0:12:50Er, but on their, on their feet they have a, a large big toe,
0:12:50 > 0:12:53erm, which is opposable which helps them to climb.
0:12:53 > 0:12:56Well certainly those kinds of things could infer
0:12:56 > 0:12:58something about the arboreal habits, for example?
0:12:58 > 0:12:59Definitely, definitely.
0:13:03 > 0:13:07'Although these lemurs have evolved to become omnivores, their diet
0:13:07 > 0:13:11'is still largely the same as Ida's, eating mostly leaves and fruit.'
0:13:12 > 0:13:16So I notice they take the food mostly directly from
0:13:17 > 0:13:22our hands to their mouth, rather than taking it in their hands
0:13:22 > 0:13:23and manipulating it,
0:13:23 > 0:13:26in what we might think of as the typical monkey fashion.
0:13:26 > 0:13:28Yes, they prefer to take things directly, erm,
0:13:28 > 0:13:31with their mouth rather than holding it in their hand.
0:13:33 > 0:13:35And a lot of these primates have very good sight
0:13:35 > 0:13:38- and very sensitive hearing.- Mm-hm.
0:13:38 > 0:13:41Er, and perhaps, I don't know how sensitive the nose is as well?
0:13:41 > 0:13:46Smell is very important for lemurs, it's how they mark their territory.
0:13:46 > 0:13:50- So they will use their smell.- To deter other males?- To deter, yeah.
0:13:50 > 0:13:54They can also do a stare as well, erm, which, er...
0:13:54 > 0:13:57- I can think of one or two human males who do exactly the same.- Yeah.
0:14:01 > 0:14:05So now we have an image of Ida, but what about the climate and
0:14:05 > 0:14:10ecosystem in which she lived, with whom did she share the Messel world?
0:14:17 > 0:14:22The Messel site has revealed all sorts of other remarkably preserved fossils which help us
0:14:22 > 0:14:26piece together the flora and fauna from 50 million years ago.
0:14:28 > 0:14:32'The fossil flora is housed under the care of Dr Volker Wilde.'
0:14:32 > 0:14:36It's all here. So we've got a vast collection here?
0:14:36 > 0:14:40Yes, er, for more than 30,000 individual specimens from Messel
0:14:40 > 0:14:43- and...- From Messel alone? - Yeah.
0:14:43 > 0:14:48- And, er, how many species represented that you know about anyway?- Far more than 200.
0:14:48 > 0:14:52- So it might outnumber all, well it does outnumber all the mammals and reptiles...- Yes.
0:14:52 > 0:14:54- ..put together.- Yes, definitely.
0:14:56 > 0:14:59Now we, we must look at some of these plants and...
0:14:59 > 0:15:03- Yes.- I think maybe a flower because, you know in poetry...
0:15:03 > 0:15:07- Yes.- ..in every other way a flower is the definition of what doesn't last.
0:15:09 > 0:15:12OK, so all you can see at the moment is black on black,
0:15:12 > 0:15:14under glycerine to stop decay,
0:15:14 > 0:15:18but if I tilt the light just in the right way, can you see?
0:15:20 > 0:15:21It's a fossil flower.
0:15:21 > 0:15:25And, er, the pollen grains are preserved in situ which is
0:15:25 > 0:15:27extremely rare in the fossil record.
0:15:34 > 0:15:39This amazingly well preserved flower is an ancient relative of the water lily.
0:15:40 > 0:15:44Many other flowering plants, angiosperms,
0:15:44 > 0:15:45flourished in the Messel period.
0:15:50 > 0:15:54Flowering plants of course are arguably the most important organisms
0:15:54 > 0:15:59- on the surface of the land today. - Yes, and in Messel times, er,
0:15:59 > 0:16:02you have to imagine a situation which is quite similar to today.
0:16:02 > 0:16:09The diversity of angiosperms was similar to the diversity of flowering plants today.
0:16:09 > 0:16:12- That's, it's one example where plants win over animals.- That's it.
0:16:12 > 0:16:15- Even though the animals tend to be cuddly.- Yes.
0:16:18 > 0:16:19This anatomy, er...
0:16:20 > 0:16:24'These rare fossilised records of plant life suggest'
0:16:24 > 0:16:27that the average temperature was well above 20 degrees Centigrade.
0:16:31 > 0:16:36And the water lily isn't the only specimen which is surprisingly familiar.
0:16:37 > 0:16:40I can recognise that, that's a bean pod.
0:16:40 > 0:16:41Yeah. That's it.
0:16:41 > 0:16:44Erm, and, er, it, well it looks like a bean pod.
0:16:44 > 0:16:46- Yes, they do.- And I think I could probably say that is a bean pod.
0:16:46 > 0:16:49- It is, definitely. - Er, and of course the bean family
0:16:49 > 0:16:52- is enormously widespread today, isn't it?- Yeah.
0:16:52 > 0:16:54Well this is an extinct bean,
0:16:54 > 0:16:57so I suppose might one might refer to it as a "has bean".
0:16:59 > 0:17:03Wherever you find plants you normally find insects.
0:17:03 > 0:17:08And another fossil takes us into the insect world that surrounded Ida.
0:17:08 > 0:17:12Dr Sonja Wedmann studies another fossil which has modern descendants.
0:17:15 > 0:17:16- Hello.- Hello, Richard.
0:17:16 > 0:17:18So this is the home of the fossil insects?
0:17:18 > 0:17:20Yes, it is.
0:17:20 > 0:17:22And, well I can see...
0:17:25 > 0:17:28there's a thin little outline,
0:17:28 > 0:17:32as I go back I can see the body expanding.
0:17:35 > 0:17:36So what sort of insect is it?
0:17:36 > 0:17:40Yeah, it's a leaf insect, it, it's the only one worldwide,
0:17:40 > 0:17:42it's, it's a really amazing.
0:17:42 > 0:17:46- So this IS the fossil record of the leaf insects?- Yes.
0:17:46 > 0:17:48- And you have pet ones? - Yes, I have.
0:17:48 > 0:17:49- So we can have a look?- Yes.
0:17:54 > 0:17:55They're hiding very well.
0:17:59 > 0:18:01This is a, a young leaf insect.
0:18:05 > 0:18:08You, you don't have to be an expert entomologist to see that
0:18:08 > 0:18:11- fossil is very similar to this... - Yes!
0:18:13 > 0:18:16And look how it's rocking. Is that a fo...
0:18:16 > 0:18:18Er, does that have a purpose, do you think?
0:18:18 > 0:18:23It's part of their camouflage, they move like a leaf moving in,
0:18:23 > 0:18:26in the wind and that they are camouflaged.
0:18:26 > 0:18:30And of course the wonderful thing about these is today they're found
0:18:30 > 0:18:33in South East Asia so we, we have another example, yet another example
0:18:33 > 0:18:38in Messel of something that today has their relatives scattered all
0:18:38 > 0:18:42over the world, erm, particularly in the Americas and Africa.
0:18:43 > 0:18:46Er, but in Eocene times here they were in Germany.
0:19:09 > 0:19:14If you want to get a visual impression of Messel
0:19:14 > 0:19:21you could do worse than coming here, in deepest Berkshire, to, er, the living rainforest.
0:19:24 > 0:19:27Er, here are a, a whole range of tropical trees
0:19:27 > 0:19:30and animals live together in glorious profusion.
0:19:38 > 0:19:43The world of Messel was a strange mixture, in part familiar, in part unfamiliar.
0:19:43 > 0:19:47It was undoubtedly a rainforest and like rainforests today there
0:19:47 > 0:19:51were large reptiles living in the trees and on the ground.
0:19:53 > 0:19:55There were also a variety of birds.
0:19:56 > 0:19:59Some of them were large ground-dwelling predators.
0:20:01 > 0:20:07And there were mammals that were related to familiar species today, but they were different,
0:20:07 > 0:20:09often they were small compared with their living relatives.
0:20:14 > 0:20:16It was a greenhouse earth.
0:20:18 > 0:20:20Carbon dioxide levels were higher.
0:20:22 > 0:20:24There were probably no polar icecaps.
0:20:25 > 0:20:29As a whole it as known as the Eocene Thermal Maximum.
0:20:34 > 0:20:38Amid the plants and insects of this warm and humid rainforest,
0:20:38 > 0:20:41Ida certainly wasn't the only mammal forging a niche for herself.
0:20:50 > 0:20:5330 minutes north of the Messel Pit, is a museum that shows very
0:20:53 > 0:20:59clearly how over the last 65 million years mammals have evolved to fill
0:20:59 > 0:21:04almost every ecological vacancy left by the extinction of the dinosaurs.
0:21:08 > 0:21:11But some of the early mammals who shared Ida's ecosystem,
0:21:11 > 0:21:13whilst perhaps recognisable,
0:21:13 > 0:21:16looked very different from those that roam the earth today.
0:21:23 > 0:21:26One of the very best examples of this strange combination
0:21:26 > 0:21:32of similarity and dissimilarity, is a mammal that has helped shape the course of civilisation.
0:21:32 > 0:21:36- And this is one of the so-called... - The horse.
0:21:36 > 0:21:39In here is one of the primitive small horses.
0:21:39 > 0:21:42Oh, that is absolutely beautiful.
0:21:43 > 0:21:47- It's, er...- It's one of these ones that's been completely separated from the oil shale.
0:21:47 > 0:21:51The preparation is very nicely done, you can see every detail.
0:21:54 > 0:22:00This is Propalaeotherium sometimes known as the Dawn Horse.
0:22:01 > 0:22:03Standing at the same height as a mid-sized dog,
0:22:03 > 0:22:07it's the creature from which our modern horse ultimately descended,
0:22:07 > 0:22:09as Dr Sandra Engels explains.
0:22:11 > 0:22:12So what about diet?
0:22:12 > 0:22:15What can we tell from this specimen about diet?
0:22:15 > 0:22:19You can see that they have teeth that are suited for leaves,
0:22:19 > 0:22:24- but they also have blunt cusps that crush, yes...- Like this?
0:22:24 > 0:22:28And we also have gut content and when you look at it under
0:22:28 > 0:22:34a microscope you can find particles of leaves or seeds inside.
0:22:36 > 0:22:41But it's not like the living horses because it's eating leaves and nuts if it can find them.
0:22:41 > 0:22:44- Yeah.- So this started out, the horse started out more like say
0:22:44 > 0:22:46a living deer which mostly browses in their habits.
0:22:46 > 0:22:50- Something like this.- And then moved into the grasslands later on.
0:22:50 > 0:22:53As we know from Messel, it was, er, a rainforest.
0:22:55 > 0:22:58This Dawn Horse lived in dense rainforests
0:22:58 > 0:23:0115 million years before wide grasslands had developed.
0:23:05 > 0:23:09Early horse species had yet to evolve the prominent physical characteristic
0:23:09 > 0:23:13which many of us assume to be the defining feature of a horse.
0:23:15 > 0:23:16The single hoof.
0:23:21 > 0:23:25It seems to me that we've got rather a large number of toes
0:23:25 > 0:23:30- compared with the living horse.- Yes, they have four digits at the front
0:23:30 > 0:23:33and three toes at their back legs.
0:23:35 > 0:23:39That the third digit, the middle digit is already pronounced here.
0:23:39 > 0:23:42And so this is a many-toed horse,
0:23:42 > 0:23:45- but it's already showing horsiness...- That is true.
0:23:45 > 0:23:46..by that enlarged digit.
0:23:49 > 0:23:51As the environment changed,
0:23:51 > 0:23:55this third toe would evolve into the hoof of the modern horse.
0:24:02 > 0:24:05Here in the Royal Veterinary College north of London,
0:24:05 > 0:24:10horses are diagnosed and treated for all kinds of ailments under
0:24:10 > 0:24:12the watchful eye of Dr Renate Weller.
0:24:14 > 0:24:18This gives us a perfect opportunity to get down to the details of horse anatomy.
0:24:23 > 0:24:27So you're looking at one particular foot of this particular horse?
0:24:27 > 0:24:30- Yes.- Because there's something wrong with it?
0:24:30 > 0:24:34Indeed, and so we have many, many parts in there that can go
0:24:34 > 0:24:40wrong, bones, joint, er, several ligaments, a tendon running
0:24:40 > 0:24:43on the back of the horse's leg and into the foot, and this allows us
0:24:43 > 0:24:48to evaluate all of them and then choose appropriate treatment.
0:24:50 > 0:24:52By using the latest technology,
0:24:52 > 0:24:55we can see how far the modern horse has evolved since his
0:24:55 > 0:25:00diminutive relative scampered through the rainforests of Messel.
0:25:06 > 0:25:12This is our MRI scan of the foot and of course one toe.
0:25:12 > 0:25:16Er, absolutely which makes it actually easier to look at it
0:25:16 > 0:25:17if you only have one toe.
0:25:19 > 0:25:20When you look very carefully
0:25:20 > 0:25:25we can see the tendon has ruptured er, some of its fibres,
0:25:25 > 0:25:28so this is a very common injury we see in
0:25:28 > 0:25:33horses and, well one of the reasons is because the way it has evolved.
0:25:34 > 0:25:40But why one toe compared with our little several digited Dawn Horse?
0:25:40 > 0:25:47Well, one is much more stable, it doesn't have that splay effect,
0:25:47 > 0:25:52it also gives the horse the opportunity to have a very light foot.
0:25:52 > 0:25:57And so, er, speed and endurance were part of the story?
0:25:57 > 0:25:59Yes, the horse is, is an amazing creature.
0:26:01 > 0:26:06The evolution of the horse's hoof is almost unique among grazing mammals.
0:26:06 > 0:26:09For the horse is both sprinter and long distance runner.
0:26:12 > 0:26:16But humans of course have capitalised on that speed part...
0:26:16 > 0:26:21- Yeah.- ..and changed the horse in certain ways.
0:26:21 > 0:26:24If you look at, at, at this, er, section, er,
0:26:24 > 0:26:28- that's of, of a horse's, er, leg, this, this...- So bred for length.
0:26:28 > 0:26:31This is bred for length, er, can I borrow your finger.
0:26:32 > 0:26:36Then we have, you have a relatively tiddly, er, metacarpals
0:26:36 > 0:26:38whereas in a horse, this is very long.
0:26:39 > 0:26:44We have the toe bones which start here, er, corresponding to this.
0:26:46 > 0:26:48The next bone is here, corresponding to this one
0:26:48 > 0:26:53and then the final bone with your fingernail corresponding to
0:26:53 > 0:26:55that horned capsule that surrounds the horse's foot.
0:26:55 > 0:26:57So that's my, my hoof...
0:26:57 > 0:26:59- That's your hoof... Absolutely. - ..in a way.
0:27:06 > 0:27:11The story of the horse demonstrates the Mammalian ability to adapt to changing ecosystems.
0:27:13 > 0:27:16So when the Messel rainforest eventually gave way to
0:27:16 > 0:27:19grasslands, the horse changed with it.
0:27:22 > 0:27:25And side by side we can really appreciate just how far
0:27:25 > 0:27:28they've come over the past 50 million years.
0:27:35 > 0:27:38The sheer number of extraordinary fossils through which
0:27:38 > 0:27:40we can bring to life the Messel world,
0:27:40 > 0:27:43means it's all too easy to take them for granted.
0:27:48 > 0:27:52Yet each one is actually the product of painstaking conservation skills.
0:28:01 > 0:28:05These shales, they dry up very, very quickly.
0:28:05 > 0:28:09This is a, a bowfin fish coming out here and the, the specimen
0:28:09 > 0:28:13has dried out and is now very, very difficult to conserve.
0:28:18 > 0:28:21Fortunately in this World Heritage Site,
0:28:21 > 0:28:25techniques are available which make these specimens permanent
0:28:25 > 0:28:28and save their scientific information for future generations.
0:28:32 > 0:28:36As soon as a new find is made it is quickly brought from the pit
0:28:36 > 0:28:38to this storeroom just a few minutes away.
0:28:39 > 0:28:43Here, these treasures of Messel are kept sealed until
0:28:43 > 0:28:47they are ready to be removed from the oil shale that encases them.
0:28:57 > 0:29:02Once exposed, the fossils must be kept wet at all times to stop the oil shale from drying out.
0:29:15 > 0:29:19So the, er, specimen has come out of storage...
0:29:19 > 0:29:22'Dr Krister Smith, of the Senckenberg Museum,
0:29:22 > 0:29:24'takes me through this delicate process.'
0:29:24 > 0:29:27And a very long process it is.
0:29:27 > 0:29:30Of course it's not like the preparation I've done because it's under water.
0:29:30 > 0:29:31Absolutely.
0:29:31 > 0:29:34A specimen must be kept moist at all times,
0:29:34 > 0:29:38the oil shale here has a water content of about 40%
0:29:38 > 0:29:42and if left to dry out, the entire fossil will crumble away.
0:29:42 > 0:29:44And the matrix, the oil shale itself is being
0:29:44 > 0:29:47scraped off little by little to expose the fossil.
0:29:47 > 0:29:51So he's very carefully removing flake by flake every little
0:29:51 > 0:29:52bit of mineral in there.
0:29:54 > 0:29:57And for a big specimen this can take days?
0:29:57 > 0:29:58- Months.- Months.
0:30:02 > 0:30:06This technique is perfect for preserving the fossils of Messel.
0:30:08 > 0:30:12But perhaps somewhat surprisingly it relies on a bit of British
0:30:12 > 0:30:16ingenuity, first set out in 1950 by Harry Toombs
0:30:16 > 0:30:18at the Natural History Museum.
0:30:22 > 0:30:27Toombs had been using acids to extract fish fossils from various soft rocks.
0:30:27 > 0:30:31But deprived of the rock they were held by, the bones could fall apart.
0:30:35 > 0:30:37To keep their structural integrity,
0:30:37 > 0:30:39Toombs hit upon the idea of stripping out one
0:30:39 > 0:30:43side of the rock and then replacing it with a plastic resin.
0:30:48 > 0:30:51So the specimen here is still a little bit moist
0:30:51 > 0:30:54and what we need to do is first dry the surface
0:30:54 > 0:30:56so that the epoxy can adhere.
0:30:57 > 0:31:00That's the kind of, er, technical...
0:31:00 > 0:31:03equipment I can cope with quite... confidently.
0:31:07 > 0:31:08I guess you gotta make sure you don't get air bubbles
0:31:08 > 0:31:13trapped in there because that would be both unsightly
0:31:13 > 0:31:17- and could obscure some scientifically important detail. - Absolutely.
0:31:25 > 0:31:28Once one side of the fossil is set in dried epoxy,
0:31:28 > 0:31:30the clay is delicately removed
0:31:30 > 0:31:34and the process can then be repeated for the other side of the fossil.
0:31:42 > 0:31:44And this is the finished result.
0:31:44 > 0:31:51A fossil bowfin removed from its rocky matrix after 47 million years.
0:31:54 > 0:31:56It's a wonderful way of studying extinct life.
0:32:02 > 0:32:06It might be hard to realise just how unusual this
0:32:06 > 0:32:07level of preservation is.
0:32:09 > 0:32:14A different extraction process at the Natural History Museum in London makes it clear.
0:32:19 > 0:32:22I take a journey into the vaults.
0:32:28 > 0:32:33So this is the scruffy part of the Natural History Museum that people don't usually get to see.
0:32:33 > 0:32:37We're off to see a special kind of washing machine.
0:32:38 > 0:32:43It's operated by the museum's mammal man, Dr Jerry Hooker.
0:32:43 > 0:32:45Ah, Jerry this is where you hide out?
0:32:45 > 0:32:48That's right, it's a very special washing machine, it's a
0:32:48 > 0:32:51clay washing machine, and it's for washing this sort of stuff.
0:32:51 > 0:32:56- Lumps of mud?- That's right and we wash the mud away and we find little tiny fossils.
0:32:56 > 0:32:58- So I'll load it in. - Take it away.
0:33:04 > 0:33:06Right, if I give you that.
0:33:06 > 0:33:08The lid goes down.
0:33:08 > 0:33:09Go and turn the tap on.
0:33:10 > 0:33:12And...
0:33:18 > 0:33:21Here we are in the inner sanctum.
0:33:21 > 0:33:22Yes, this is where the...
0:33:22 > 0:33:26'In Jerry's office, I see the next stage of the painstaking process.'
0:33:28 > 0:33:30So this is a typical residue, erm,
0:33:30 > 0:33:34after the clay machine has washed the mud away.
0:33:34 > 0:33:36Erm, it's, we haven't got there yet, er,
0:33:36 > 0:33:39what you see there is, is almost all shell,
0:33:39 > 0:33:44and there will be little tiny teeth and bones in there as well.
0:33:44 > 0:33:47But it takes forever to actually, er, pick them out,
0:33:47 > 0:33:51so we concentrate it further, and you can do that with acetic acid.
0:33:51 > 0:33:53- So you dissolve the shell? - We detach the shells, yep.
0:33:53 > 0:33:55- But doesn't touch the teeth, or bones?- That's right.
0:33:55 > 0:33:59- Then you're left with something like this? - That's exactly what's happened,
0:33:59 > 0:34:02It's the same sample, er, and that's been treated and that hasn't.
0:34:04 > 0:34:07Occasionally if you're really lucky you, you get jaws...
0:34:07 > 0:34:10- A whole jaw, well I can see... - A whole jaw
0:34:10 > 0:34:11and this is a jaw of a rodent, so.
0:34:11 > 0:34:15- So you must have been absolutely thrilled when that turned up? - Absolutely.
0:34:17 > 0:34:20Well they're very hard one, they're beautiful three dimensions,
0:34:20 > 0:34:22but of course it's not quite the same as having...
0:34:22 > 0:34:25- It's not the same as having... - ..all the fur and the gut contents.
0:34:25 > 0:34:28..the whole animal, that's right. You, you need both.
0:34:30 > 0:34:33'Finding mammal fossils in the UK is the paleontological
0:34:33 > 0:34:36'equivalent of finding a needle in a haystack.
0:34:36 > 0:34:38'A tooth in a clay bed perhaps.
0:34:38 > 0:34:42'And helps to remind us how detailed and miraculous the Messel discoveries are.'
0:34:48 > 0:34:53Messel rodents, for example, can be found with three different designs.
0:34:57 > 0:35:02One was built for speed with long back legs.
0:35:02 > 0:35:08One elaborately protected with bristles.
0:35:08 > 0:35:10And one with an unlikely combination of both.
0:35:15 > 0:35:18The mammals of the Eocene period were already beginning to
0:35:18 > 0:35:22display the traits that would help them surpass many competitors.
0:35:25 > 0:35:30Most importantly they were rapidly adapting to their surroundings.
0:35:34 > 0:35:38There is one familiar mammal that shows just how similar animals
0:35:38 > 0:35:42could evolve into subtly different species, all able to occupy
0:35:42 > 0:35:45and exploit a different niche within the same ancient environment.
0:35:47 > 0:35:51- Oh!- They are also the most abundant mammals found at Messel.
0:35:53 > 0:35:54Bats.
0:35:59 > 0:36:02'Dr Jorg Habersetzer shows me his collection.'
0:36:03 > 0:36:08So here you have the smallest species, this is, er,
0:36:08 > 0:36:12one extinct family represented by two different species.
0:36:12 > 0:36:14This one was flying very close to the surface
0:36:14 > 0:36:16of the former Messel Lake.
0:36:16 > 0:36:19And we have a second family, and...
0:36:19 > 0:36:21And is that also a low flyer?
0:36:21 > 0:36:25No, this er, er, bat was flying in a middle corridor,
0:36:25 > 0:36:29that means in-between trees and in a flight altitude of,
0:36:29 > 0:36:32let us say eight to 15 metres.
0:36:32 > 0:36:37And, finally, here these are already very highly sophisticated
0:36:37 > 0:36:39specialist by means of echolocation.
0:36:39 > 0:36:42So that's the same echolocation that living bats use?
0:36:42 > 0:36:45- Yes.- And is that actually a member of a living group?
0:36:45 > 0:36:46This is also true.
0:36:46 > 0:36:51When you, erm, when you unfold, er, all this skeletal elements here...
0:36:51 > 0:36:53So that's like an umbrella that's spread out?
0:36:53 > 0:36:58Yeah, it is a bat with a very narrow slender wing, it is
0:36:58 > 0:37:02- a typical morphology of a rapid and high flying.- A high flyer.
0:37:04 > 0:37:08Every bat species living today can trace a line back to the
0:37:08 > 0:37:11characteristic wing forms and echolocation
0:37:11 > 0:37:13present in the seven species found in the Messel Pit.
0:37:17 > 0:37:20And just from a common sense point of view, people might think a bat
0:37:20 > 0:37:25is an extraordinarily specialised mammal and yet here we have bats...
0:37:25 > 0:37:30- Yeah.- ..in Messel, whereas some of the other perhaps more familiar mammals, predators...
0:37:30 > 0:37:32- Yeah.- ..large herbivores have yet to appear.
0:37:34 > 0:37:37So, if we're got seven species of bats
0:37:37 > 0:37:42and we've got a whole ecology from low, middle and high altitude.
0:37:42 > 0:37:46- Yeah.- Obviously there must have been a lot of previous bat evolution.
0:37:46 > 0:37:49- Yes. - About which we know nothing.
0:37:54 > 0:38:00By the time of the Eocene, these bats had already become finely-tuned specialists.
0:38:02 > 0:38:06Flying at three distinctly different heights they would have been
0:38:06 > 0:38:09able to find food where other competing animals could not.
0:38:14 > 0:38:19But however well adapted these bats, Ida and other mammals were
0:38:19 > 0:38:22they were not without competitors.
0:38:22 > 0:38:26Some people might think that the demise of the dinosaurs was
0:38:26 > 0:38:28also the decline of the reptiles.
0:38:28 > 0:38:31Nothing could be further from the truth.
0:38:31 > 0:38:37The Messel fauna proves the reptiles were evolving as vigorously
0:38:37 > 0:38:41alongside the early mammals as ever in their history.
0:38:43 > 0:38:46I've come to talk reptiles with Dr Krister Smith.
0:38:48 > 0:38:51- Richard.- Lovely to see you. - And you as well.
0:38:51 > 0:38:52And we're gonna talk reptiles?
0:38:52 > 0:38:56We are. I have just the specimen to show you.
0:39:05 > 0:39:06Fantastic!
0:39:08 > 0:39:10It's a snake and more besides.
0:39:10 > 0:39:17Indeed, this on a superficial view looks to be a lovely specimen
0:39:17 > 0:39:22of a snake, it also happens to be a yet un-described species of snake.
0:39:22 > 0:39:25- So it doesn't have a name yet? - It doesn't even have a name.
0:39:25 > 0:39:28And if you look more closely as you've just done,
0:39:28 > 0:39:32you'll notice that there is something more inside it.
0:39:32 > 0:39:35I, er, er, it's sort of lizard like?
0:39:35 > 0:39:40It is in fact a lizard which is found inside the...belly of the snake.
0:39:40 > 0:39:44Now when the specimen is first prepared, you will also see
0:39:44 > 0:39:47this black content inside the belly of the lizard.
0:39:49 > 0:39:52OK, I can see it more as a black smudge here.
0:39:52 > 0:39:53That's right.
0:39:53 > 0:39:57And the paleo-entomologists tells us that this is a beetle
0:39:57 > 0:40:01inside the belly of the lizard, inside the belly of the snake.
0:40:01 > 0:40:04So what we have here is a one-specimen food chain?
0:40:04 > 0:40:08That's exactly what it is, something like a Russian doll, if you will.
0:40:08 > 0:40:11The poor beetles, they've been food ever since they evolved.
0:40:11 > 0:40:12HE LAUGHS
0:40:17 > 0:40:22Then as now, insects were a rich source of nutrition,
0:40:22 > 0:40:25high in protein for reptiles, mammals and birds.
0:40:30 > 0:40:34The extraordinary thing about Messel is that it contains not just
0:40:34 > 0:40:39the large fossils like mammals and birds and a host of reptiles
0:40:39 > 0:40:44but also the fossils of small things, particularly insects.
0:40:45 > 0:40:50And in the tropical rainforests of Messel they came in all shapes and sizes.
0:40:53 > 0:40:55So, Sonja, what have we got first?
0:40:55 > 0:41:01Yeah, we have here a nice big cockroach. Yeah, it's really big.
0:41:01 > 0:41:03Almost five centimetres long.
0:41:05 > 0:41:09- So cockroaches did then what they do now...- Yes.
0:41:09 > 0:41:11..which is scuttle along on the forest floor
0:41:11 > 0:41:14- eating almost anything that's edible?- Exactly.
0:41:15 > 0:41:18And they're the great survivors, they've already been around
0:41:18 > 0:41:21- for 200 million years or something like that...- Yes.
0:41:21 > 0:41:23- ..by the time they arrive at Messel. - Yes.
0:41:25 > 0:41:29Moving...delicately on.
0:41:29 > 0:41:31These are so-called giant ants.
0:41:31 > 0:41:36- They are indeed. And, er, aren't they called something like...?- Yes.- That's right.
0:41:36 > 0:41:39Which obviously means the titanic ant,
0:41:39 > 0:41:46- and very special indeed and, may I pick it up?- If you want.
0:41:47 > 0:41:52There we are, we can see through this slab to see these gigantic,
0:41:52 > 0:41:57- and these are queens, are they? - Yes, they are.- So this is the big flying generation for these ants.
0:41:57 > 0:42:01Erm, and in fact the, this is the smaller species,
0:42:01 > 0:42:05we have two species in Messel of these ex...extinct giant ants.
0:42:05 > 0:42:07- They get bigger?- Yes.
0:42:11 > 0:42:13And perhaps the most surprising thing of all...
0:42:15 > 0:42:20- This is a jewel beetle. - A jewel, oh my goodness, yes.
0:42:20 > 0:42:25We can see why a jewel beetle. Because it's got iridescence.
0:42:28 > 0:42:31And when you think that that is caused by structures
0:42:31 > 0:42:37that are, er, microns across, thousandths of a millimetre across,
0:42:37 > 0:42:42- that just testifies to the extraordinary preservation at Messel.- Yeah, that's really true.
0:42:46 > 0:42:50And the supreme quality of preservation doesn't end there.
0:42:53 > 0:42:57These insects even retain fossil colour, and new research is
0:42:57 > 0:43:01illuminating the secrets of such preservation in surprising detail.
0:43:08 > 0:43:13Working at the forefront of fossil science, studying colour and how
0:43:13 > 0:43:17it's preserved, is Dr Maria McNamara from the University of Cork.
0:43:23 > 0:43:26She's trying to understand the role and evolution of colour in nature.
0:43:29 > 0:43:33And she's devised an innovative method of recreating the past.
0:43:34 > 0:43:36Baking.
0:43:40 > 0:43:43This is what the beetles look like before cooking.
0:43:47 > 0:43:51I've seen a beautiful fossil beetle in Messel which shows colour,
0:43:51 > 0:43:55and this is a living relative, a jewel beetle, so can
0:43:55 > 0:44:00I believe my eyes with what I saw on the Messel fossil, is it real?
0:44:00 > 0:44:04That's a really good question because, erm, it's possible
0:44:04 > 0:44:07when you look at the fossils that the colour you see could have been
0:44:07 > 0:44:11generated during the fossilisation process, an artefact, and they
0:44:11 > 0:44:16may not be related to the original colour of the insect at all.
0:44:16 > 0:44:21Erm, however when we look at the fossil beetles using powerful
0:44:21 > 0:44:25electro-microscopes, we find the exact same evidence of colour
0:44:25 > 0:44:28that we see in these modern beetles.
0:44:28 > 0:44:32You see these modern beetles, the colour we see, it's not made by pigments,
0:44:32 > 0:44:36it's made by very fine layers.
0:44:36 > 0:44:39And these layers act like mirrors, so they reflect light, erm,
0:44:39 > 0:44:46and they actually reflect light in such a way that we get a very pure, a very bright colour.
0:44:50 > 0:44:52But nonetheless time has done something to the colours?
0:44:52 > 0:44:57Exactly, the, the, the interesting twist in the story is, are the
0:44:57 > 0:45:01colours we see preserved today, the original colours of these insects?
0:45:03 > 0:45:04- Well let's have a look.- OK.
0:45:08 > 0:45:11'By using high pressure, high temperature ovens,
0:45:11 > 0:45:15'Maria can replicate the process of millions of years of fossilisation.
0:45:17 > 0:45:21'And reconstruct the original colour of the Messel fossils.'
0:45:22 > 0:45:28We have one of these modern jewel beetles that has been in the oven for one hour.
0:45:31 > 0:45:34I can see that that's, er, much bluer,
0:45:36 > 0:45:39a brighter blue compared with the original one.
0:45:39 > 0:45:44It is, so the colour is changing, and here's what the colour
0:45:44 > 0:45:47looks like after it's been in the oven for 24 hours.
0:45:47 > 0:45:50- And it's gone quite indigo in colour?- Yes.
0:45:50 > 0:45:55So what's going on is we have a very clear progressive colour change.
0:45:55 > 0:45:58Our green colours are being blue shifted,
0:45:58 > 0:46:03gradually turning blue, indigo. Eventually, if you were to leave it in for several days,
0:46:03 > 0:46:05it would turn black, the colour would be destroyed.
0:46:07 > 0:46:11But that's also a shift in time isn't it, this is a, a, a...
0:46:11 > 0:46:18We're going back in time and as the insects get buried, the heat increases.
0:46:18 > 0:46:21Exactly, the deeper you go, the hotter it gets.
0:46:21 > 0:46:23So we know the fossils have been buried,
0:46:23 > 0:46:26we know they have been heated up, so now
0:46:26 > 0:46:29we can actually start to quantify how much the colour has changed.
0:46:30 > 0:46:34So when we look at a, a Messel fossil, which is
0:46:34 > 0:46:38sort of up this end of the colour, we know that
0:46:38 > 0:46:42when it was alive, it had the same colour as our living jewel beetle?
0:46:42 > 0:46:46Exactly. To work, to backtrack and get back to the original colours,
0:46:46 > 0:46:48we have to work in this direction.
0:46:48 > 0:46:52So regardless of how much the colour has changed,
0:46:52 > 0:46:56we know for a fact that they had these wonderful metallic
0:46:56 > 0:46:59iridescent colours, and they were probably using them
0:46:59 > 0:47:02for the same purpose that the modern relatives use them for.
0:47:02 > 0:47:07- Such as?- Such as, erm, well in this case, we would say sexual signalling,
0:47:07 > 0:47:09we'd say to attract mates.
0:47:09 > 0:47:12But in other cases these metallic colours can actually be used
0:47:12 > 0:47:16to, erm, to deter predators, to scare off predators.
0:47:16 > 0:47:19So for once you could say that cooking the results is
0:47:19 > 0:47:21- the right thing to do? - That's it.
0:47:26 > 0:47:29It's an unusual thought that the same technique that insects
0:47:29 > 0:47:33use today to repel mammal predators
0:47:33 > 0:47:36date back 50 million years or more into the past.
0:47:42 > 0:47:46Yet none of these insights would be possible were it not for the
0:47:46 > 0:47:50ancient Messel Lake that became a watery grave for so many animals.
0:47:53 > 0:47:57The lake was formed during a period of heavy volcanic activity.
0:47:59 > 0:48:02'And as Dr Stephan Schaal tells me,
0:48:02 > 0:48:06'Eocene Germany was a particularly volatile place.'
0:48:06 > 0:48:10And the volcanic rock is implicated in the formation of this great hole.
0:48:10 > 0:48:12- Right.- What happened?
0:48:12 > 0:48:16The hot magma came up and got in contact with the ground water,
0:48:16 > 0:48:19and the, er, er, there followed a lot of explosions and the
0:48:19 > 0:48:24result was a big hole, an enormous hole, a natural catastrophe it was.
0:48:24 > 0:48:27And that was followed by the hole being filled which made
0:48:27 > 0:48:31- the lake where our animals lived and died?- Yes.
0:48:31 > 0:48:32We've still got a well here, have we?
0:48:35 > 0:48:37'In 2001...
0:48:37 > 0:48:42'the team at the pit drilled down half a kilometre into the earth's crust,
0:48:42 > 0:48:46'to confirm the theory that the lake was created by volcanic activity.'
0:48:49 > 0:48:51- And we use this...hole. - Ah!
0:48:57 > 0:49:02The borehole still remains and pumps out ancient Messel water.
0:49:02 > 0:49:05- Let's, let's, let's see what it tastes like?- Yeah.
0:49:05 > 0:49:06If I can get near enough.
0:49:10 > 0:49:11Not terribly nice.
0:49:13 > 0:49:16No. It tastes of iron, iron and sulphur.
0:49:16 > 0:49:21And the sulphur is the last little gasp of that volcanic eruption.
0:49:21 > 0:49:24And the age of this water may be around 14,000 years.
0:49:32 > 0:49:35So, what caused the presence of such a wealth of fossils
0:49:35 > 0:49:38at the bottom of this ancient lake?
0:49:44 > 0:49:48One theory which accounts for the killing of the animals at Messel
0:49:48 > 0:49:51is connected with the volcanic activity.
0:49:51 > 0:49:53Although the active volcano had ceased,
0:49:53 > 0:49:58from time to time belches of carbon dioxide were released,
0:49:58 > 0:50:04a heavy colourless gas that lay over the Messel Lake like a blanket.
0:50:04 > 0:50:07Any bat that dipped down into would be suffocated
0:50:07 > 0:50:10and fall into the water and down to be preserved in the mud.
0:50:10 > 0:50:15The same applied to animals perhaps drinking at the edge of the lake.
0:50:15 > 0:50:20These were periodic, so that through time generation of animals
0:50:20 > 0:50:23were sampled in an irregular way to be preserved.
0:50:29 > 0:50:31There is a modern analogy for this theory.
0:50:33 > 0:50:39In 1986, a huge eruption of carbon dioxide from the bottom of Lake Nyos in Cameroon
0:50:39 > 0:50:42crept silently through surrounding towns and villages,
0:50:42 > 0:50:47killing 1700 people and 3500 livestock.
0:50:51 > 0:50:54But there is an alternative killing theory.
0:50:54 > 0:50:58'It's put forward by former Director of the Messel Pit.
0:50:58 > 0:51:00'Wighart Von Konigswald.'
0:51:00 > 0:51:02Erm, turtles, they've obviously...
0:51:02 > 0:51:04'He believes one clue is the number of fossils
0:51:04 > 0:51:07'preserved in the act of mating.'
0:51:13 > 0:51:18Er, the main question is how did these animals come to, er, to die?
0:51:21 > 0:51:26It was not a catastrophe. This occurred again and again and again.
0:51:26 > 0:51:29- A regularity, then?- A regularity.
0:51:29 > 0:51:32Let's, erm, er, we've got a, a, a lovely fossil turtle here,
0:51:32 > 0:51:35let's cast some light on the subject.
0:51:36 > 0:51:39So this is... we're looking at fossil sex here?
0:51:39 > 0:51:41We look at fossil sex.
0:51:41 > 0:51:45I do not know exactly which one is male and which one is female.
0:51:45 > 0:51:49And turtles are likely to have mated at one particular time of year.
0:51:49 > 0:51:52So this was a seasonal effect?
0:51:52 > 0:51:55Yeah, a signal for a season.
0:51:55 > 0:51:58But this is not only specimen,
0:51:58 > 0:52:04we have seven or eight specimens of the turtles in mating position.
0:52:06 > 0:52:12This is an indicator that we have not a volcanic gas eruption
0:52:12 > 0:52:17which has no reason to be related to seasons,
0:52:17 > 0:52:20but there's something else.
0:52:27 > 0:52:30Von Konigswald thinks an annual bloom of cyanobacteria -
0:52:30 > 0:52:37blue/green algae - would have released poisons that formed a deadly scum on the lake surface.
0:52:40 > 0:52:45When these cells die, they produce gas inside the cell,
0:52:45 > 0:52:50so the gas floats up to the surface of the water body,
0:52:50 > 0:52:54and form a foam called a scum.
0:52:54 > 0:52:58- A poisonous foam? - And this is highly poisonous.
0:52:58 > 0:53:01If you have animals drinking from that water
0:53:01 > 0:53:04they will die immediately.
0:53:09 > 0:53:1550 million years later it's a difficult theory to prove, but research continues.
0:53:21 > 0:53:24The Messel Pit has provided palaeontologists with
0:53:24 > 0:53:27an unrivalled insight, not just into early mammals,
0:53:27 > 0:53:30but the entire ecosystem within which they evolved.
0:53:36 > 0:53:39Yet perhaps surprisingly this legacy was almost lost.
0:53:40 > 0:53:44And I gather were it not for the actions of some of you
0:53:44 > 0:53:47and some of your colleagues, there might be no pit at all here?
0:53:47 > 0:53:49That is possible, yes.
0:53:55 > 0:54:00In the 1970s, just as the true significance of the site was being realised,
0:54:00 > 0:54:04the local government tried to sell off this great pit for landfill.
0:54:08 > 0:54:12'Dr Stephan Schaal was at the forefront of a 20-year struggle that came to an end
0:54:12 > 0:54:17'when the pit was awarded the status of a World Heritage site.'
0:54:17 > 0:54:20So how did you feel after nearly 20 years of campaigning
0:54:20 > 0:54:23when suddenly you'd won a Unesco site?
0:54:23 > 0:54:27Er, it was a wonderful feeling indeed, if you're fighting for
0:54:27 > 0:54:31something for 10, 20 years and then suddenly from one day to the other
0:54:31 > 0:54:34that you have the decision, you have to read it two times to believe it.
0:54:34 > 0:54:38It was a great feeling and it lasts till today.
0:54:38 > 0:54:44- And so now, well, I'm happy to say this is safe, as safe can possibly be.- Yes.
0:54:46 > 0:54:50Their efforts saved a unique window into an ancient time,
0:54:50 > 0:54:52and possibly the origin of the human line.
0:54:58 > 0:55:02The Messel menu almost brings the bill of fare up to date.
0:55:05 > 0:55:08What have we got for Messel munchies, practically a modern smorgasbord.
0:55:08 > 0:55:11Er, remember the giant ants in Messel,
0:55:11 > 0:55:14well, I guess this is their modern equivalent.
0:55:18 > 0:55:19They were food for the...
0:55:19 > 0:55:24mammals at Messel, but, and they can still be food, but they are a bit dry.
0:55:26 > 0:55:31Well, I think I'm gonna tuck into some grub or in this case actually some caterpillar.
0:55:31 > 0:55:33So now we've got pollinators.
0:55:34 > 0:55:35Oh, goodness me.
0:55:37 > 0:55:41Erm, well, I mean if I'm honest it tastes just like wood.
0:55:42 > 0:55:45Oh! Well, main course is...
0:55:46 > 0:55:50Of course we've now got a variety. This is lamb.
0:55:50 > 0:55:51Heart possibly.
0:55:53 > 0:55:55Hm. Quite succulent.
0:55:56 > 0:56:02And, of course, the ubiquitous pig that formed so much of modern society's diet.
0:56:08 > 0:56:14And all washed down with the, the essence of mammal milk,
0:56:14 > 0:56:17well this could be horse, it could be cow, it could be goat.
0:56:21 > 0:56:22Ah!
0:56:22 > 0:56:25And perhaps afterwards, well maybe some fruit, because of course
0:56:25 > 0:56:28the flowering plants and fruits have evolved by then.
0:56:28 > 0:56:29But what's missing?
0:56:31 > 0:56:33Bread, the staff of life,
0:56:33 > 0:56:37because those kinds of cereals have not yet evolved.
0:56:37 > 0:56:41So this particular slice of life had to await the future.
0:56:49 > 0:56:56In this series, we have sought out and revealed the secrets of three long vanished worlds.
0:56:57 > 0:56:58Wow!
0:57:01 > 0:57:05Each represents a key moment in the narrative of the deep past.
0:57:08 > 0:57:14And reveals new insights into the design of life and the story of evolution.
0:57:25 > 0:57:29There may be a vision of evolution as a kind of steady progression,
0:57:29 > 0:57:33almost like a train that moves inexorably from station to station,
0:57:33 > 0:57:39perhaps reaching a junction where two branches diverge into different directions.
0:57:39 > 0:57:43We know now that evolution happened in bursts of creativity.
0:57:44 > 0:57:49We know that small worm-like animals could evolve to walk on land.
0:57:50 > 0:57:54We know that dinosaurs acquired feathers that became
0:57:54 > 0:57:58capable of flight and produced birds.
0:57:58 > 0:58:04We know that mammals no bigger than a mouse could evolve into a mammoth.
0:58:04 > 0:58:05Transmutation is all.
0:58:06 > 0:58:10We've seen life trapped in stone, we've seen events
0:58:10 > 0:58:17trapped in time, but evolution can only work with what it's given,
0:58:17 > 0:58:23which is why there will never be a mermaid nor sadly an angel.