'Of all the animals that live on our planet,
'one extraordinary group dominates.
'It has produced the largest...'
The blue whale!
'..the fastest,
'and the most intelligent creatures
'that have ever lived.
'They're known as the vertebrates,
'and they all share one vital feature.
'A backbone.
'Now, I want to travel back in time to explore their ancient origins.
'And investigate the key advances that led to their amazing success.'
Advances that can also reveal
how we came to acquire the characteristic features
of our own vertebrate bodies.
Jaws that bite, lungs that breathe, ears that can hear.
Because the story of the rise of animals
is also the story of how you and I came to be as we are.
'I will find evidence in a series of spectacular fossil discoveries
'around the world and within living animals.'
That's it.
'With the latest scientific analysis,
'we can bring our ancient ancestors back to life.'
And understand how, over 500 million years,
they developed the bodily features needed to master the seas...
..colonise the land, and take to the skies.
This is the story of the rise of animals.
The history of life on Earth
has been known in outline for many years,
but there were a number of tantalising gaps in it,
particularly in the history of animals with backbones.
When, for example, did the first signs of a backbone appear?
And is it really true that dinosaurs developed feathers
and turned into birds?
Well, in recent decades,
answers have been found to those extraordinary questions,
here, in China, and I'm here to look at them.
China is the new frontier for fossil discoveries.
Excavations here are unearthing links in the story
of the vertebrates that have so far eluded us.
I have long wanted to see this sensational evidence for myself.
I will be travelling to the frozen north of the country,
and to the capital, Beijing.
But to search for the first step in our journey,
I'm heading south, to Yunnan Province.
This is the site of a thrilling discovery that has given us
new evidence for the very first vertebrates.
Excavators here are exposing a rich seam of rocks
known as the Chengjiang fossil beds.
Remarkably, they contain the remains of creatures that once swam
in the ancient seas 525 million years ago.
'Palaeontologist, Hou Xianguang, was the first to discover
'the unique features of these beds,
'an astonishing perfection of preservation.'
Are these mouth parts?
Yeah. That's very beautiful.
You can see it's got striations on it.
'To find complete bodies like this is extremely rare.'
When an animal dies in the sea,
normally bacteria destroy the soft parts very quickly
so that all we can find afterwards are the hard parts, bone or shell.
Why that didn't happen here in this particular part
of this particular sea is something of a mystery.
It may be something to do with the lack of oxygen,
but whatever it was, it has given us a privileged view
into one of the most exciting chapters
in the whole history of life.
The beds have so far yielded over 200 separate species.
This was a time period known as the Cambrian.
The land was still bare and lifeless,
but, underwater, it was exploding into a multitude of forms.
The major animal groups we know today were appearing on the planet
for the very first time.
They built their bodies entirely of soft tissue.
Some protected and supported it with a hard outer casing.
But none had anything that resembled a backbone.
These were the invertebrates.
'Then, Professor Hou and his team found one intriguing exception.'
Oh, yes, yes, yes.
It's a fossil called Myllokunmingia.
But to examine it in detail,
you've got to look at it under the microscope.
Its features reveal evidence of a new type of support,
not outside the body, but inside.
This is one of about 30 specimens that have already been found
of this tiny little creature.
Under the microscope, it contains an extraordinary amount of detail.
Those marks are marks that have been made by the excavator's needle.
This is the animal itself. This is its head, the top of its back.
And nearly every one of them have these two little black spots
at the front, eye spots.
Looking farther down the animal,
there are just some striations here,
little bars which are thought to have been the gill bars,
the little constructions that carry blood vessels
which enabled the animal to extract oxygen
from the waters it flowed over and breathe.
And behind them, farther down the animal, there are these bars...
..bands of muscle, and they were probably attached to a gristly rod
somewhere in the middle there.
This is called the notochord,
which was the forerunner of the backbone.
Myllokunmingia is the earliest creature we know of
that we can truly call a vertebrate.
And it seems clear that it used its strong inner rod
to move in an entirely new way.
As the muscles contract, they bend the rod from side to side.
This movement pushes against the water and creates forward thrust.
Here was a revolutionary new way to get around.
It allowed Myllokunmingia to roam far and wide and escape
the dangerous invertebrate predators that were prowling the seas.
The vertebrates would diversify over millions of years
to create the spectacular variety of backboned creatures we see today
in every environment on the planet.
Fish dominate the seas, lakes and rivers.
The amphibians live in both water and land.
The reptiles can survive in the driest places on Earth.
The birds rule the skies...
..and the mammals have insulated their bodies
to adapt to every climate.
We humans have used our greater intelligence to overrun the planet.
This astonishing journey
was built on a series of key evolutionary steps
that helped our ancient ancestors to exploit their environments
and overcome huge challenges.
The first of these advances was the development
of that inner support - the notochord.
Back in Europe, you can find a creature that represents
the next critical step in our story.
It lives unobtrusively and often ignored in British rivers.
And it sheds light on the challenges those first vertebrates faced.
Ah, there it is!
This is a lamprey.
You might think at first sight that it was a kind of fish, but it's not.
It's something much, much more primitive.
It has no fins, and even its tail
is nothing more than a flattened blade.
But what is most remarkable about it
is that it doesn't really have a true mouth.
Its mouth is just a simple hole
with little bristles about it.
And it feeds by sucking in water through that mouth
and then filtering out little particles of food.
So this little animal takes