Lost Worlds, Vanished Lives (1989–…): Season 1, Episode 4 - The Rare Glimpses - full transcript

The sunlit waters of a shallow sea.

Life here is rich and varied.

Jellyfish, sea gooseberries and all kinds
of larvae drift in the dappled waters.

On the bottom, sea anemones wave among the
rocks and small worms wriggle within crannies.

Everywhere you look,
there seems to be life of some kind.

Creatures like these
have a very ancient ancestry.

They were among the first
forms of life to appear on earth

and they existed for several hundred million
years before the development of fish,

the first animals with backbones.

But when such creatures with no bones
in them die, what remains of them?

Almost nothing. Their soft tissues
simply disintegrate and dissolve in the water,



and there's hardly anything left of them
but a little slime in the mud.

Only a minority, a few molluscs with hard shells,
crustaceans like crabs with external skeletons,

only they leave any signs of their existence
after their flesh has vanished.

So of all that multitude of creatures,

only one or two could leave behind in the mud
any evidence that they had ever existed.

This, too, was once mud at the bottom of a sea
but that was over 500 million years ago

and now it's mudstone
and high in the Canadian Rockies.

And these rocks, too, contain the remains
of the hard parts of sea animals,

and very extraordinary animals, too.

They're now totally extinct
and we call them trilobites.

But there's virtually nothing else
but trilobites in these rocks,

so what did the trilobites live on
and, maybe, what hunted the trilobites?

The answers to questions like those
could only be guesswork

until, that is, the year 1901.



In that year, an American geologist,
Charles Walcott,

was exploring here in the Rocky Mountains
of British Columbia,

travelling on horseback
with a train of pack mules.

He was in his 60th year and coming towards
the end of a long and distinguished career

in which he had made a special study of the
ancient fossil-bearing rocks of North America.

When he got to this precise point on the trail,

where this slip of loose rocks crosses it,
one of his horses stumbled.

Walcott dismounted to clear the path,
and when he did so,

he hit one of the boulders with his hammer,
as he must have done ten thousand times before.

Only this time, when the boulder fell apart

it revealed a fossil the like of which he had
never seen before in all his experience.

To his amazement,
he saw that it had its soft parts preserved:

Tentacles, the head and a row of small legs
on either side of its body.

If he didn't do so then,
he must have realised very soon afterwards

that this was the most important
discovery of his life.

So the next season,
he and his sons returned to this place

to try and find out
where that boulder had come from.

They climbed up the rock tip,
looking for fossils as they went

and knowing that the highest level at which
they found any fragments with fossils in them

must be the place
from which all the fossils were coming.

And that proved to be just here,

and this place has been
the site of research ever since.

A band of these shales just seven foot thick
produced all the fossils.

Walcott came here for the next eight seasons,
and in that time he collected 61,000 specimens,

and two-thirds of the species that he found
proved to be new to science.

Animals such as these, with delicate legs,
with tiny gills and threadlike antennae,

must have been living throughout the seas
of this very ancient period.

They had never been seen before
because everywhere else, being soft-bodied,

they had simply dissolved
and disappeared without trace.

Only here, for some extraordinary reason,
had they been preserved,

and preserved, what's more, in amazing detail.

This was some kind of worm,
presumably a burrower in the mud,

with an extendible proboscis.

And here a most remarkable find,
a worm with fleshy legs,

a possible link between true worms

and more complex invertebrates
such as centipedes and insects.

These rocks are known as the Burgess Shales.

How is it that one thin band of them
on this particular mountainside

preserved signs of life
that are found nowhere else in the world?

That was one of the questions Walcott and his
successors spent a long time trying to answer.

The latest group of scientists
to work on the site here

come from the Royal Ontario Museum
and are led by Des Collins.

530 million years ago, this was
a muddy sea floor about 400 feet deep

and was directly in front of a massive, sheer cliff

that you can see
in this light-coloured material here.

The reef front rose
in a sheer cliff about 300 feet high.

You can see at the top the bedded rock,
which is where the animals lived in a lagoon

about 100 feet deep or less.

Every so often, the mud at the top
would come down in a slump,

picking up the animals, bringing them down here,

killing them and burying them
and preserving them in the mud.

This happened at a time when
complex animals had only just appeared,

so the ultimate ancestors of all life today
must therefore be among them.

This worm, with an internal rod
running along its length,

may be the ancestor of all backboned animals.

And this, with five pairs of claws on its head,

may be the creature from which scorpions
and spiders have evolved,

for it shares some of their
most significant characters.

This, with what seems a protrudable proboscis,
is more of a puzzle.

It may be related to certain kinds of living worms.

And this bizarre creature
is quite unlike anything alive today.

It had seven pairs of legs,
seven tentacles on its back, each with a mouth.

It seems to have been one of evolution's
experiments that simply didn't work very well,

and it's left no descendants.

By examining the best of these specimens,

it's possible to deduce from the flattened outlines
what it was like before it was squashed flat,

and to reconstruct it in three dimensions.

The liquid mud often penetrated
the insides of the animals,

separating each tiny organ from the other
by a microscopic film of mud particles,

and then it's possible to work out
details of internal anatomy.

This creature swam by waving flaps beneath it
and it sensed its food with long feelers.

But some specimens are so strange,
it's difficult to make head or tail of them.

This, for example, three or four inches long,
looks like some kind of shrimp,

except that none
has ever been found with a head.

And this, rather like a slice of pineapple.
Could this be some kind of jellyfish?

Though there are still some speculations,

we now have a picture
of a large and varied community.

But if there were so many
of these mud munchers and filter feeders,

there must surely have been some hunter
that preyed on them. What was that?

That question troubled a British palaeontologist,
Harry Whittington,

as he worked on some of Walcott's specimens.

Searching through many thousands of them,

he found one in which that pineapple slice
seemed to be attached to some other structure.

What is more, there were
several other specimens rather like it,

including one that was
not completely cleared of matrix,

and he started very carefully to investigate it.

...if you think this is the underside of the body,

to look and see, is there anything perhaps
attached to the underside

that goes down into the rock?

And there was a little area here.

And using a little drill, you could
very delicately work along the edge here

and remove flakes of rock.

And gradually this thing became exposed

and I realised, particularly when I got to this end
and saw the characteristic spines on it,

that was this thing
that had been described many years before,

anomalocaris, the strange shrimp,

and people thought this was part of an animal
and envisaged it having a little shell here,

but no whole one had ever been found.

Now here was one
attached under the front end of this animal.

Was that an accident? If there was one
one side, there ought to be one the other.

Indeed, there was a layer in the rock here

and I exposed parts of that chiselling around here,

and there exposed is part of the companion one
that was attached there.

That predator was revealed.

The headless shrimps were its claws
and the pineapple slice was its muscular mouth.

This was the terror of the trilobites.

So now we have an even more complete picture

of the life that flourished on the sea floor
530 million years ago.

We knew it must have contained
the ancestors of all subsequent life,

but now we have some idea
of what they looked like.

The next exceptionally detailed glimpse
we get of the progress of life

comes from this valley in southern Germany,
near a village called Solnhofen.

140 million years ago, that's 400 million years
after the time of the Burgess Shales,

this part of Europe lay under the sea,
as we know because it's covered by limestone,

but this valley is lined by cliffs of a special kind.

When you examine the rock
of these huge towers,

you see that it's composed
not of thin, horizontal layers of sediment,

but of curving plates.

And these are, in fact, the fossilised remains
of sponges and other reef-building organisms

which, growing one on top of the other,

over centuries
slowly built these huge, pillar-like reefs.

While they were living, beneath the sea,

they sheltered the water
lying between them and the shore

from the waves and currents of the open ocean

and they created a shallow lagoon.

Conditions then must have been rather like
they are today in other shallow tropical lagoons

where the water evaporates so fast
that it becomes extremely salty,

and calcium carbonate in solution
starts to precipitate

as an extremely fine, limy mud, layer upon layer.

Over millions of years,
the mud compacted and turned to stone.

The land level rose and the sea drained away.

The river in the Solnhofen valley eroded
much of it, exposing those coral cliffs again.

But elsewhere, the limestone remains.

And now, as stone, those layers
can be separated, where it's weathered,

into plates almost as thin as paper.

And where it's not weathered,
it formed a magnificent building stone

that's been worked in places like these
since Roman times.

If the rock splits into plates an inch or so thick,
it can be used for roofing.

Where it's more massive, it's cut into blocks
for masonry of such quality

that it has been used all over Germany.

In the 19th century, a local man
discovered yet another use for it.

If you draw a picture on it with wax pencil,

you can, using a special ink, take
an almost unlimited number of copies from it.

He called the process lithography,

and it was widely used to print illustrations
for a hundred years or more, all over Europe.

But every now and again,
when the quarrymen come to split a block,

they open it and find that there's an illustration
already printed within it,

an illustration that's 140 million years old,

like this one

A fish.

Fossils are not abundant, for few animals could
live in this inhospitable, near-sterile lagoon.

These fish were swept into it,
past the reefs, by sudden storms.

But though there are few of them,
their preservation is near-perfect,

for the storm that carried them in
also stirred up the mud

and, as they died, that settled back
and covered them like a shroud.

A fish with grinding teeth,
like a parrot-fish of today,

which presumably fed in the same way,
pulverising coral to extract the little polyps.

A kind of garfish.

A bottom-living ray,

a species that seems to have survived
almost unaltered until today.

This lobster, too, had ancestors
that strayed into the Solnhofen lagoon.

Crustaceans, with their hard external skeletons,

make excellent subjects for preservation
under these conditions.

And backboned animals, too,
with their skeletons of bone,

are also beautifully preserved.

A turtle, its flesh gone but its bones very clear.

Another reptile, with an amazingly long body
and an even longer tail.

Yet, because of the infrequency
of the currents in the lagoon,

all its bones remained perfectly positioned
while the flesh decayed around them.

And because of that extreme stillness,

even a jellyfish settling gently on the limy mud
has left the delicate impress of its soft body.

Tracks on the lagoon floor
have also remained clear.

This one was obviously made
by an animal with several long legs.

The scratches between the footprints
suggest that it also had a spiky tail.

And it seems to have been lost,
for it's wandering aimlessly about.

We're looking at the story of one small death
that took place 140 million years ago,

for here's the body,
complete with that trailing tail.

It's a horseshoe crab,
virtually identical with the horseshoe crabs

that still today swim
in the seas off North America.

Other tracks are not so easily interpreted.

What about, for example, this extremely rare
but rather mysterious mark?

Is it perhaps some kind of worm?

Well, it seems to have been caused
by an empty ammonite shell

that fell down into the mud, making a dent,

and then, carried by a current,
rolled until it came to the mouth again,

which caused it to leap up, fall again,
and then roll again.

Insects flying over the lagoon
sometimes flopped into the water and sank.

A dragonfly.

A winged grasshopper.

And a much bigger flying animal, a pterosaur,

the membrane of its skinny wings plainly visible.

But there's one animal in particular,

whose remains drifted down through the salty
water and settled on the mud of the lagoon,

that has made the name Solnhofen
famous worldwide.

Its remains are so excessively rare,
and so important to science,

that they've been called
"the most valuable fossils in the world".

The most perfect of them,
which is kept here in East Berlin,

is so valuable that it's kept locked away
in a safe, away from public view,

and exhibited only as a replica.

This is a rare privilege to see the real thing.

Archaeopteryx, a creature that represents
a link between reptiles and birds.

It's birdlike because it's covered
not by fur but by feathers.

Their intricate structure, each with a central quill
and barbs coming off it on either side,

can be clearly seen.

They are virtually identical to modern feathers.

Its wings are modified front legs,

but not as greatly altered
as the wings of modern birds,

for three of their five toes
still have claws at their tips,

projecting from the front edge of the wings.

The feet had backward-pointing big toes,
which gave the animal a firm grip on a branch,

and that, too, is characteristic of birds.

The head, however, is not at all birdlike.

It had no beak,
but a bony, reptilian jaw lined with teeth.

And here, reptilian and bird characteristics
combined in one feature, the tail.

No bird has bones in its tail like this,

and while reptiles do,
none of them has feathers on it.

In recent years, the question was raised
as to whether these really were feathers,

but the closest examination
of another specimen in London

has proved conclusively that they certainly are.

So, thanks to the limy burial shrouds
of Solnhofen

we can make a detailed reconstruction

of this key creature
in the history of the evolution of life.

But reptiles were still, at this time,
the dominant animals.

Gigantic seagoing crocodiles like this one
roamed the seas.

Huge pterosaurs bigger than any eagle
soared through the air.

And on land, there were the dinosaurs.

The reason we know so much about dinosaurs
is that many were very big,

with tough bones that could survive
being washed down by the rivers

and buried in the deposits of the delta.

But 67 million years ago,
the last of the dinosaurs died.

For some time, the land
was comparatively underpopulated,

but then the early mammals began to spread.

But they were not big creatures
with tough bones

but small animals with delicate skeletons
that were easily destroyed.

Neither did they live in a lagoon
where there were regular deposits,

but on land, where there was virtually none.

So they were comparatively
poor candidates for fossilisation

and we knew very little about them until, at last,

another of these extraordinary
fossil sites was discovered.

At Messel, near Frankfurt, in Germany,
there's a deposit of shales so rich in oil

that quite spontaneously,
they catch fire and burn underground.

The oil comes from the tissues
of animals and plants

living in the lake
that lay here 48 million years ago.

The shales were once
worked commercially for their oil,

but they contain
much more valuable things than that.

48 million years is a comparatively short time
for mud to turn to rock.

Solnhofen limestone is three times as old,
the Burgess Shales over ten times,

and these shales are still soft and moist.

The excavators have spotted
the remains of a fish,

but it mustn't be fully exposed to the air
because if it dries out, it'll disintegrate,

so the slab is carefully cut out
and taken to a laboratory.

There it's kept moist while the compressed mud
is delicately scraped from the flank of the fish.

Once that side has been cleaned
as far as possible, liquid resin is poured over it.

When that sets, it's perfectly transparent,

so now specimens treated in this way
can be worked on from the other side.

Eventually, virtually all the mud can be removed,

and the fragile bones are held firmly
in a block of transparent plastic.

This is one of the early mammals
for which Messel is now famous,

a tiny horse that was no bigger than a spaniel.

Gerhard Storch,
from the Senckenberg Museum in Frankfurt,

is one of the team working on these finds.

Unlike recent horses,
they possess four digits in the forefeet,

one, two, three, four.

- Both legs are there, aren't they?
- Yeah, there are both legs, side by side.

- And perfect little hooves.
- And perfect little hooves, yeah.

The grinding teeth are not tall and high
in the jaw like those of a modern horse,

but low, indicating that the animal
ate soft leaves and fruit,

and that's confirmed by examining the stomach.

With a scanning microscope,
we can investigate the last diet of these horses.

In this specimen,
the gut contained soft leaves from tropical plants.

- So it was living, what, in the woodlands?
- It was living in a dense, tropical forest.

And there are even stranger things in the muds
of Messel than spaniel-sized horses.

This is a mammal that belongs
to a very archaic group close to insectivores

and this group became extinct.

The forelimbs are very small, very reduced.

The hind limbs are long, elongated.

The tail is very long.
It's a world record for mammals.

It consists of about 50 single vertebrae.

And all of these body proportions tell us

that this animal was moving on its hind limbs,

but not in a way that is familiar to us
from kangaroos or jerboas,

running fast and very manoeuvrable
on the hind limbs but with alternating steps.

(ATTENBOROUGH) So really
there's no equivalent alive today?

(STORCH) There is no analogue today.

There is also, believe it or not,
an ancestor of hedgehogs.

The texture of bone on the front of the skull

shows that the flesh there
was particularly thick with blood vessels,

which suggests that there was
some kind of gland or shield on its forehead.

And there are true birds, many kinds,

some so excellently preserved that almost
the only detail you can't make out is their colour.

And not only birds, but bats,
and several kinds of them as well.

But why should so many flying animals
have fallen dead into the lake?

Something must have happened to these bats
while they were hunting on the wing,

and my idea is that there were
poisonous gases on the Messel lake

and a bat which went down drinking
came to such a gas bubble

and fell down to the water's surface.

So, because of those freakish conditions
40 million years ago,

the vanished lake of Messel
now yields evidence

about not only the animals
that swam in its waters and lived in its forests,

but even those that populated the skies.

Los Angeles, in America.

Hardly world-famous for its fossils,
but it should be,

for in the heart of this most modern of cities

is a site that gives another wholly
exceptional picture of a vanished world.

40,000 years ago,

this was the appearance of the land
on which hotels and freeways now stand.

Firm evidence for every single detail
in this most detailed painting

comes from a small park close by
one of the city's main avenues, La Brea.

In one corner of it, through the harmless grass,

oozes a substance that kills - la brea, tar.

It wells up from the ground here
to form these black pools.

When it rains, water lies on top of it,

and it looks like a place
where you might get a drink.

But any animal that came here to do so
would be lucky to escape alive.

Feet sink into the tar, feathers get entangled in it,
and the animal is fatally trapped.

That's been happening
for 40,000 years and more,

and it's still happening today.

Tar, like oil, is derived
from the bodies of animals and plants

that accumulated in swamps.

The sand that was deposited on top of them
squeezed their remains

so that droplets of oil
were expelled from their tissues.

That accumulated in basins
within the texture of the porous sandstone

and then, where there is a fault,
this substance is forced up to the surface.

The earlier flows of tar,
containing the most ancient animals,

have now been covered by later flows,

so to reach them,
you have to dig down into the tar pit,

and excavations which started
back at the beginning of this century

are now being carried on some 30 feet down,

while the tar still rises
around the excavating platform.

The work is supervised by trained scientists,

but most of the team
is made up of local volunteers.

(MAN) 0K. This is ready to go. Got the bag?
(W0MAN) Yes, I do.

(MAN) That's a sabre-toothed cat femur.
(W0MAN) Right or left?

(MAN) That's a right.

(W0MAN) And without his epiphysis.
(MAN) Right.

(MAN) What you got over there, Jerry?
(JERRY) I've got this ulna uncovered here.

- What's it lying on top of?
- It's lying right across a sabre-tooth cat skull.

The finds have been put on display
in a museum recently built on the site,

and very spectacular they are.

In addition to this magnificent imperial mammoth,

the biggest of all the prehistoric elephants
that lived in North America,

there were extinct horses and camels
which grazed on these plains.

Huge, long-horned bison.

There were over 20 species
of eagles and falcons.

Ground sloths the size of small elephants.

These huge animals are now totally extinct.

They browsed the trees and,
like the rest of these plant-eaters,

only rarely and accidentally
strayed into the tar pits.

But once an animal like this
was mired and stuck,

it made the pits a positive attraction
to packs of wolves.

These dire wolves were
about the same size as living wolves

but with more massive heads.

Struggling, trapped animals
were obviously something they couldn't resist,

for wolves, in fact, are the commonest
of all the victims of the tar pits.

The most frequently trapped
grass-eaters were the bison,

so there were probably big herds of them,

but, again, the pits contain more bones
of the animal that preyed on them,

the American lion.

The females were about the same size
as African lions,

but the males were 25% bigger.

And there was an even more impressive cat,
the sabre-tooth.

At one time it was thought that these
extraordinary teeth were daggers for stabbing,

but now it's believed that they were used
to slit open the belly of the prey.

You might wonder how the animal
managed even to close its jaws,

and I asked a scientist at the museum,
George Jefferson, to explain.

I think we can illustrate that best with
the specimen here that was preserved closed.

That will give us an idea
what that mouth looked like.

As you can see, the incisors actually interlaced,
allowing the jaw to fully close.

I'm surprised how much space there is

between those huge sabre teeth
and the lower jaw.

That gap is the same gap as between
the meat-slicing teeth on the side of the face.

What that meant is,
the animal would disengage the incisors,

drop the jaw down, move it slightly sideways,

and guide the slicing blades here

by running the inside of this flange
against the canine tooth.

- Is that a new discovery?
- It is. In fact,

we didn't know this gap was that way
until we found this specimen.

As well as big animals, the tar preserved
a whole range of organisms that lived here.

Even pollen grains can be obtained from it,

and it's they that have enabled the artist
who painted the reconstructed landscape

to show the correct species
of flowering bush, Californian sage.

The museum's laboratory
is surrounded by glass windows,

so that those working on the finds
become exhibits themselves.

I think this rib's going in like that,

and if you look at the top,
the way it angles round,

- I think there's probably a little edge.
- So it's going back under.

Once you've discovered what animals
were present, why go on digging up more?

Well, the museum has over 200 jaws of bison.

As George Jefferson explained,
their sheer number gives new information.

With these three specimens here,

we can see an animal three years old,
two years old and one year old.

We can tell that
from the eruption stage of the teeth.

Here we see this tooth being pushed out -
this animal is three years old.

We don't have specimens
representing intermediate ages

between three years old and two years old,
nor two and one year old.

That tells us that these animals are coming here
periodically at a certain time of year.

We can determine that season by comparing
the stage of wear on these teeth

with modern bison who have
a very restricted calving period.

They're here in the late springtime.

- So they're migrating?
- Yes.

The multitudes of jaws, therefore,
prove that once in California,

great herds of bison
made long migratory journeys,

and that every year, after the rains, when the
grass began to sprout on the Hollywood hills,

there was great carnage around the tar pits.

The sheer abundance of the dire-wolf skulls
also yields information.

They are not, of course, all the same,
and the differences are not all due to age.

The lumps and distortions that are apparent,
compared to the smooth forehead on this animal,

indicate an infection
in the frontal sinuses of the forehead,

probably as the result
of being kicked in the face,

maybe by a bison or a camel.

This animal was obviously
going after its prey and getting injured.

We also see injuries in the sabre cats.

We see chronic injuries to the back.

Here we have three lumbar or back vertebrae

that have been fused together
by a mass of bony tissue.

This bony tissue grows along the ligaments
and muscles where they're injured and stretched

while this animal is lunging for its prey.

In this hip...

...we have a fairly normal hip socket here,

but on this side you can see a lot of knobbly bone,

a distortion and break,

there are flanges of extra bone in here.

This animal was obviously in a lot of pain
while this healing was going on.

We think it may have been butted
by a bison, hit very hard,

or even, possibly, by a mammoth elephant.

- So he's really a cripple.
- Yes.

It's astounding it lived as long as it did.

Some researchers believe this is evidence

that the injured and infirm were being tolerated
within the population and possibly cared for.

- So social behaviour among the sabre cats?
- Social behaviour.

It seems almost miraculous
that any remains of animals

could survive for tens of thousands of years,
let alone hundreds of millions.

In exceptional circumstances, like the tar pits
of La Brea or the volcanic lake of Messel,

the hot lagoons of Solnhofen and the muddy
submarine avalanches of the Burgess Shales,

they leave clues that tell us
not only about their appearance,

but their detailed internal anatomy,
their daily habits, even their social life.

Fossils have been forming
ever since life appeared on this planet

and lie in the earth all around us.

They provide us with irrefutable and wonderful
evidence of what existed before we did.

Sometimes the latest high-tech apparatus
is needed to reveal it,

sometimes it needs nothing more
than a simple blow from a hammer

and logical, clear-minded thought.

But slowly, piece by piece,

we're putting together
the history of the long procession of life

that preceded mankind's appearance
upon this planet,

and of which, indeed, we are a part.