All action, all movement, is driven by energy. Nothing can happen without energy.

Jeffrey West is a physicist at the Santa Fe Institute in America.

Not just the motion of the planets around the Sun or the motion of your automobile,

but even to have a dream at night requires energy. Energy is underlying everything.

Hello, I'm Justin Rollatt and welcome to the first episode in the Pyra Technic History of Humanity

here on the BBC World Service. In this series, I'll be exploring our species' unique relationship

with energy, which I believe explains our ascent to global domination.

What makes a special is how we've managed to harness ever more powerful sources of energy.

In each episode, I look at one of three energy revolutions that created us and our civilization

plus a fourth revolution which we hope will save us from ourselves.

And the first of these revolutions takes us right back to the dawn of our species.

The discovery of fire by prehistoric man was the initial discovery

that stored in wood is energy. The sun's energy grew trees by photosynthesis and when they die,

we can release that energy.

But when our ancestors first learned to strike sparks from a flint or just grabbed a burning branch

from a wildfire, what would they have used it for? The energy released all that heat and light

could be put to some pretty obvious uses, keeping warm at night, seeing in the dark,

warding off predators, but the most significant use was probably none of these.

Instead, it may have been something we all take for granted today, something that uses the

energy of fire to release even more energy in our food. Anything that allows in organism

to get energy more efficiently is going to have huge effects on the evolutionary trajectory of that

organism. And I believe that cooking has played an essential role in shaping the way that humans are

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