- The idea that there is an inevitable trajectory
towards complex life and perhaps towards
something like humans is a little bit wishful thinking.
The origin of complex cells happened just once on earth.
If we think about other planets,
the likelihood is we'll find bacteria.
And this idea that we are somehow more evolved
than bacteria is not really true.
I work on the deep history of life--
the origin of life
through to the evolution of early cells
and what that means for us today.
Why do we age?
Why do we get diseases?
Why are we conscious?
Why have there been long gaps, two or three billion years
where it's just bacteria and nothing else?
And you can't explain that just in terms of genes.
We wouldn't know anything about what happened
in the first two billion years of life on Earth
if it hadn't been for gene sequencing.
But life is not only about information.
It's about the structure of cells.
It's about the turnover of molecules,
how gases in the environment
are converted into more molecules.
None of this has anything to do with genes.
All of this happens spontaneously.
I think my work's important because it's asking
some of the biggest questions in science.
What I'm doing is putting back a side
that's been missing for a long time,
which is energy flow and its importance,
and how that changes the way that evolution happens.
The strange thing is very few people in the world
are thinking along those lines,
and it has an ability to come up with an almost
alternative view of the whole history of life.
If I say "origin of life" to you,
virtually everybody will say "primordial soup."
I think the idea of the primordial soup is a terrible idea.
It just won't go away.
The thing about life is it has structure.
It has movement.
It is a continuous chemical reaction,
and the problem with any kind of soup
is it's basically not reactive.
It doesn't have the flow of energy going through it.
And so I think it's a really bad way
of seeing the origin of life,
and I much prefer to think about,
"What are cells doing?"
And "What's the simplest version
of how cells become animated?"
"Are there geological environments that work that way?"
And the answer is yes, there are.
I think life started down in the deep oceans
in hydrothermal vents,
but the earth was very different four billion years ago
because there was no oxygen back then.
And if you're working on the origin of life, which I do,
then you're starting with really simple prebiotic chemistry.
We're trying to do it under strictly anoxic conditions.
So in the strict absence of oxygen.
But the questions are really very simple questions
about how can we have the simplest possible version
of a hydrothermal vent in a lab?
So we use, in a sense, as little technology
as we can get away with.
Nobody can agree about what complex life actually means.
What I mean is the difference between bacteria
and the kind of cells that make up animals and plants,
and single-celled organisms that eat other things.
Our kind of cell, it's called the eukaryotic cell
which just means it's got a nucleus
and the DNA's packaged away in the nucleus.
They're a lot bigger, a lot more complex than bacteria.
All these complex cells in plants, in animals, in fungi--
they all have basically the same structure.
Our kind of cell arose
once in four billion years of evolution.
And it seems to have been something
of a bit of a freak accident.
For two billion years we have just bacteria,
and the bacteria remain as bacteria.
Then we have an abrupt single origin
of all complex cells that happens
around two billion years ago.
And then we have another long period of stasis
until the Cambrian explosion where suddenly animals appear.
Nearly a hundred million years after that,
we finally get plants on land.
Hundreds of millions of years longer,
and then we are beginning to see humans evolving,
and consciousness, as we would recognize it.
What explains these long gaps?
What kind of evolutionary process gives rise
to two types of life that live in completely different ways?
Perhaps it's nothing to do with genes and information.
Perhaps it's something to do with the cell's structure.
So we have these mitochondria, which were bacteria once,
and they seem to have arisen around two billion years ago.
And the answer is almost certainly,
that another cell got inside,
and that changes the topology.
It changes the way that energy works in cells.
Now it's internalized, and that means you can expand.
You can do different things.
It opens up the floodgates to evolution.
We are a continuous chemical reaction
and we are continually burning food and oxygen.
Life has a very central logic, which is to do with growth.
Growth is really just doubling.
It's converting whatever's in the environment
into more of yourself.
And we've got a circulatory system
which is continually delivering oxygen
right to the mitochondria deep within cells.
Cells are tiny things
and the membrane is almost invisibly small.
If you were to iron out the membranes in the mitochondria
in our own body,
you'd get about four football pitches' worth of membranes,
and all those membranes have got a charge across it.
Which, if you were to shrink yourself down
to the size of a molecule,
is equivalent to a bolt of lightning.
That's what's animating us.
We're basically powered by electricity.
We would not be moving at all if it wasn't for energy flow.
That gives you different insights.
Genes work in a specific environment.
That environment is cells.
Cells have a particular structure
and that structure conditions
what the genes can and cannot do,
and so when we bring energy into it,
we begin to understand
this peculiar trajectory of life on earth.
See, one thing in biochemistry which is really striking,
the way that plant cells work,
the way that bacteria work,
the way that animals work,
it's all the same.
There is a commonality that gives me a very
strong fellow feeling with the rest of life.
This deep similarity in everything.
Then you have this amazing variation.
It's astonishing that you can use
these building blocks to come up with a world
which is so different.
That is the glory of evolution.