This is Earth. Four point four billion years ago.
A toxic world with no hope of life.
Then everything changed.
Another planet, Thea, smashed into Earth
and the two planets fused,
creating a brand new world.
Even today, Thea lies right beneath our feet.
A smaller chunk of Thea became our moon.
And slowly our oceans formed.
Until life on Earth was ready to begin.
But who would inherit this blue planet?
This series tells the extraordinary story of life before the dinosaurs.
A time when strange and savage
creatures fought a ruthless battle to rule the Earth.
Amongst them were our own earliest ancestors,
whose survival would decide whether we humans would exist at all.
As they evolved,
these bizarre creatures created the blueprint
not only for our bodies,
but for everything living today.
This is life's forgotten story.
An epic war for our world.
A war between monsters.
This is our planet,
five hundred and thirty million years ago.
Nothing yet lives on land,
but in the ocean it's a different story.
Life has already been evolving for millions of years
at a slow and steady pace.
The seas are full of simple,
soft bodied creatures,
blindly drifting in the currents.
Now, however, in the coastal shallows below,
evolution has stepped on the accelerator.
Predators have taken their first bite.
This is Anomalocaris, Earth's first super predator.
This two metre long monster owes his success
to a monumental evolutionary landmark.
They may look bizarre but they're not unique.
Many predators in the Cambrian seas
have also evolved eyes.
And so have their prey.
The consequences have been explosive.
Being able to see and react to enemies
has triggered an arms race between hunter and hunted.
This battle continues today
and is a major force behind the variety of life.
To combat being visible and vulnerable,
eighty percent of creates in these shallow seas
have sturdy skeletons on the outside of their bodies.
These armoured animals are called Arthropods.
In the future,
they'll give rise to insects and spiders.
But in these crowded waters
there's competition everywhere,
and even the mighty Anomalocaris's defences are constantly put to the test.
Rigid armour splits if bent too far,
leaving the loser vulnerable.
To a completely different threat.
This is Haikouichthys.
He's the size of your thumbnail,
but he's an evolutionary giant.
He's the first ever fish.
Our earliest known ancestor.
because instead of having armour on the outside,
he's tough inside.
He's evolved a primitive backbone.
He's the very first vertebrate.
Forerunner of all future backboned animals,
from the dinosaur, to the elephant, to us.
His flexible backbone makes him
more manoeuvrable than spineless Anomalocaris.
He can scavenge flesh, then dart away unharmed.
Our tiny backboned ancestors have survived a sea of monsters,
but there are still many more battles ahead.
They must adapt or die.
Evolution takes over.
As millions of years pass,
fish build on their basic design.
The muscles around their backbone
evolve into a powerful tail and fins appear.
They evolve a distinct head.
He may not look like you or I,
but this odd fish is becoming the blueprint for our own bodies.
This is Cephalaspis.
She's a peaceful grazer who sucks up algae through her jawless mouth.
But she's also developed a tough protective head and thick scales.
Our ancestor's arthropod enemies have also been evolving
and they're ready for round two.
A hundred million years have passed
and the fight for survival has filled the Silurian seas with variety.
Some creatures here would be recognisable today.
Sponges filter food alongside sea urchins.
The orthocone is a distant relative of squid and cuttlefish,
but he's as long as a truck.
This world is terrorised by
a new improved generation of armoured arthropods.
He's a metre long monster scorpion with gills
and a stinger the size of a light bulb.
He zeros in on his next meal.
But Cephalaspis has evolved an early warning system.
Special sensors on her skin detect the tiniest vibrations in the water.
We've inherited similar senses.
They make us sensitive to touch.
With her defensive headgear, Cephalaspis can't swim fast for long.
She must rest frequently.
Soon she'll tire completely.
Cephalaspis suddenly changes her path.
She's picking up bad vibrations.
Something Brontoscorpio can't detect.
Pterygotus is the Titan of sea scorpions.
The biggest arthropod of all time.
More than three metres long,
she's the size of a crocodile.
She has turned the tables on Brontoscorpio.
He'll make a good meal for her young.
In such dangerous seas there's nowhere to hide.
When breeding seasons comes,
the Cephalaspis congregate to head for the one place
they might escape a scorpion's grasp.
Fresh water, inland.
Land at this time is like an alien planet.
It's a barren expanse of roasting rock hotter than the Sahara.
The air would be toxic to us.
It has much less oxygen
and three hundred times more carbon dioxide than today.
But some forms of life have gained a foothold in this furnace.