- 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.
