Earlier this year, I was driving
through the countryside with a little girl of 6
and she pointed out some flowers by the wayside.
I asked her what she thought flowers were for.
She gave a very thoughtful answer.
Two things, she said.
To make the world pretty
and to help the bees make honey for us.
I thought that was a very nice answer
and I was sorry
that I had to tell her that it wasn't true.
Her answer is not too different from the answer
that most people throughout history would have given.
The very first chapter of the Bible sets it out:
"Man has dominion over all living things."
The animals and plants are there for our benefit.
This attitude was unquestioned throughout the Middle Ages
and it really persists to this day.
One pious man in the Middle Ages thought
that weeds were there to benefit us,
because it's so good for our spirit to have to go and pull them up.
And another reverend gentleman thought
that the louse was indispensable,
because it provided a powerful
incentive to cleanliness.
There's also been the suggestion that animals
positively want to do their bit for the good of mankind
and even want to be eaten by us.
Well this idea reminds me of a brilliant passage
from one of my favorite works of fiction,
"The Hitchhiker's Guide to the Galaxy" by Douglas Adams.
In fact, I'm so fond of this passage
that I was wanting somebody to read it out.
Would anybody like to volunteer to?
Right, you, please.
Your name is?
Douglas
Douglas what?
Adams.
Douglas Adams! What an amazing coincidence.
"A large dairy animal approached
Zaphod Beeblebrox's table,
a meaty, bovine quadruped with watery eyes,
small horns and an ingratiating smile on its lips.
'Good evening', it lowed and sat back heavily on its haunches.
'I am the main dish of the day.
May I interest you in parts of my body?'
Its gaze was met by looks
of startled bewilderment by Arthur
and naked hunger from Zaphod Beeblebrox.
'Something off the shoulder, perhaps?', suggested the animal.
'braised, in a white wine sauce?'
'Uh, your shoulder,' said Arthur in a horrified whisper.
'But naturally my shoulder, sir',
mooed the animal contentedly.
'Nobody else's is mine to offer.'
Zaphod leaped to his feet and started
prodding and feeling the animal's shoulder appreciatively.
'Or the rump is very good',
murmured the animal.
'I've being exercising it and eating plenty of grain,
so there's a lot of good meat there.'
'You mean, this animal
actually wants us to eat it?',
exclaimed Arthur.
'That's absolutely horrible.
It's the most revolting thing I've ever heard.'
'What's the problem, earth man?', said Zaphod.
'I just don't want to eat an animal
that's standing there, inviting me to', said Arthur.
'It's heartless.'
'Better than eating an animal
that doesn't want to be eaten', said Zaphod.
'But that's not the point!',
protested Arthur.
Then he thought about it for a moment.
'All right', he said, 'maybe it is the point.
I don't care.
I don't want to think about it now.
I'll just have a green salad.'
'May I urge you to consider my liver?'
asked the animal.
'It must be very rich and tender by now.
I've been force-feeding myself for months.'
'A green salad', said Arthur firmly.
The animal looked at him disapprovingly.
'Are you going to tell me', snapped Arthur,
'that I shouldn't have a green salad?'
'Well', said the animal,
'I know many vegetables
that are very clear on that point.
Which is why it was eventually decided to
cut through the whole tangled problem and breed an animal
that actually wanted to be eaten
and was capable of saying so
clearly and unambiguously.
And here I am.'
'Glass of water, please', said Arthur.
'Look, are we hungry or not?', snapped Zaphod.
'We'll just have four steaks, please,
very, very rare, and quickly.'
The animal staggered to its feet.
'A very wise choice, sir, if I may say so.
Very good', it said with a mellow gurgle.
'I'll just nip off and shoot myself.'
He turned and gave a friendly wink to Arthur.
'Don't worry, sir', he said.
'I'll be very humane.'"
Thank you very much.
Well however outlandish that may sound,
this sort of idea still dominates our culture,
that animals are there for our benefit.
We need to find an entirely new view of the world.
We need to try to see things
through the eyes of other creatures,
instead of all the time through our own self-interested eyes.
Flowers, the bees might say,
are there to provide us
with pollen and nectar.
But even the bees haven't quite got it right.
They're a lot more right than we would be,
if we think that flowers are there for our benefit.
The fact is that flowers,
or at least the bright and showy ones,
are there because, in a sense,
bees have cultivated them, domesticated them.
When I say bees, I include butterflies and other
sorts of pollinators.
This is why I used the word "garden"
in the title of this lecture.
But why the ultraviolet garden?
Well that's a parable,
like the parable of the Good Samaritan, or the sower.
Ultraviolet light is a kind of light
that we can't see.
It's just like ordinary light
except that it's a different wavelength
and we can't see it.
Bees can see it,
they see it as a distinct color
and bees cannot see red.
So, flowers are bound to look
very different through the eyes of bees.
And in just the same way, the question
'what are flowers good for?' is a question
that we have to look at through the eyes of bees.
Well as I say, we can't see ultraviolet
and it's no use trying to capture
what it would be that a bee would see if it looked at flowers.
All we can do is to play with a few tricks
to get some flavor of what it might be like.
Now, here is a row of tubes containing
white substances, all different white substances
They all look alike, they all look white.
But if we now expose them
to ultraviolet light for a while,
they glow different colors.
Now, this is a bit of a cheat.
We're not actually seeing ultraviolet
and none of those colors is actually ultraviolet:
those are all visible colors
that we can see.
What we are doing though is using this as a kind of metaphor
to show how what we see is changed
in ultraviolet light.
That isn't what bees would see
but it gives us an idea
of how different things might look through the eyes of bees.
Actually, flowers probably
look even more different
because when bees see shape
they see shape in a very different way from us.
When a bee sees a complicated shape
like this set of leaves here, or any of these flowers,
it probably doesn't see it as a shape like that.
It probably sees this as something that we should call "flicker."
You see little light bulbs flickering in the flowers now
and once again, that almost certainly isn't quite
what the bees see.
But it's likely to be a bit more like
what the bees see than what we see
when we see complicated shapes like that.
And now we have a film here
which again is trying to give an impression
of what the ultraviolet garden might look like.
We're seeing whole set of flowers
both as we see them, and then as the bee
might see them, in ultraviolet.
So there's a flower
as we might see it, white and yellow,
there it is as a bee might see it
with the center picked out in ultraviolet.
Once again, we see a yellow flower
and to the bee it would appear to glow
with a strange, unearthly ultraviolet light.
Again a bit of a cheat,
because we don't actually know what ultraviolet would look like.
But it's just to try to give you some idea
of how different it would be for a bee.
And in any case, we're only using this strangeness
as a parable for changing our point of view
about who or what it is that flowers
and all other living creatures are for the good of.
So let's now ask
what bees are good for from the point of view of flowers?
Well, flowers are sex organs,
designed by natural selection
to make male and female cells
and bring them together.
There are good genetic reasons
that apply in most flowers, though not all,
for making sure that they don't mate with themselves.
It would be all too easy for a flower to mate with itself:
it's got pollen and a stigma in the same physical flower,
and they use bees,
butterflies, hummingbirds and other pollinators
to transport the pollen from one flower to another.
The usual way to do this
is to bribe them with nectar.
Here you see a hummingbird
feeding from a flower with nectar.
The bright colors are like Piccadilly Circus,
it's an advertisement telling the hummingbirds
or bees to come and feed from here.
Nectar is made specially for the purpose
and it's costly.
And there are some flowers that get away without producing nectar,
like this orchid, this is a hammerhead orchid.
It mimics a wasp, and a wasp comes
and thinks that it's a female wasp
and tries to mate with it.
There's a very spectacular hinge there
that you'll see the use of - there are the pollen sacs, they're the pollinia,
and there's the hinge,
and there's the fake female.
Now look what's happened,
a male bee's come and been dashed onto the pollen there.
It's going back and forth on that hinge,
banging away.
And sooner or later
the pollen sacs will come off onto his back.
There he is now, with his back there,
and there are the pollen sacs on his back.
And he flies off and then he will mate with another flower
and the same thing will happen.
This is the bucket orchid.
An even more ingenious trick it uses:
it's dropping fluid into the bucket there.
This is an attractive fluid.
There's a special kind of green bee
which is attracted by that fluid.
It comes to the flower and it falls into the bucket.
There.
It's trapped there. The only way it can get out
is through a special hole that's provided for it by the orchid.
There's the hole,
it's the only way out and the bee has found it.
It's forced out through that hole
and on its way out there is the pollen sac waiting.
So the only way is through this little passage.
There are the pollen sacs
and it's going to get straight off onto the bee's back on the way out.
Now, that same bee, when it finally escapes
with the pollen sacs on its back, is going to fly off
and it will eventually come to another bucket orchid
and exactly the same procedure will be repeated.
It will nearly drown, it will find the hole,
and on its way out the pollen sacs
will in this case be scraped off,
and they will fertilize the next orchid.
So this is deceiving bees
and using their wings to carry pollen about.
The pollination services offered by bees are truly massive.
Somebody in Germany calculated that in Germany alone
honeybees pollinated about 10 trillion flowers
in the course of a single summer day.
It's also been calculated that about 30%
of all human foods depend on bee pollination.
If bees were wiped out,
30% of our food plants would be wiped out as well.
The world of bees is totally dominated by flowers.
I don't just mean honeybees. There are lots and lots of species of bees,
many of them are solitary, not living in hives.
The larvae of bees are almost all fed on pollen.
We've got lots of flowers. Would anybody like to come and investigate the pollen here?
Yes, please.
Now, if you'd like to just come and sniff -
try sniffing that one. Get your nose well into it.
That's right. Get well in. That's right.
What's your name? Richard.
Let's have a look at Richard's nose. You can see the pollen all over it there.
If he would go and do it to another flower,
you see another one, let's not bother. Thank you very much, Richard.
So that's what bees are doing, millions of times over, every day.
They feed their larvae on it, their aviation fuel is nectar,
and that's entirely provided for them by flowers.
They work hard for their nectar award.
To make a 1 pound jar of honey,
it's been worked out the bees would have to visit about 10 million clover blossoms.
So, flowers use bees and bees use flowers.
Both sides in the partnership have been shaped by the other.
Both sides, in a way, have been domesticated, cultivated, by the other.
The ultraviolet garden is a two way garden.
But just because flowers and bees
have evolved towards partnership
we mustn't assume that creatures in general work in a friendly way for one another's good.
There are people who think that antelopes are there for the benefit of lions
and lions are there for the benefit of antelopes,
to keep their population down.
And that's just as much nonsense as the idea that oxen
come willingly to the slaughter for the benefit of us.
In some ways it might have been better if I talked about bats
instead of about bees and flowers.
Because bats have no interest in the welfare of the insects
that they eat. They just want to eat them.
And the flies have no interest in the welfare of bats.
They'd be happy if there weren't any more bats.
So although partnerships like bees and flowers are quite common,
un-partnerships like bats and flies
are far more common.
As a matter of fact, bats provide us with another fine lesson, similar to the ultraviolet garden,
because they have an even more different perspective on the world than bees do.
If this bat were flying about
it would be making little cries, which we couldn't hear.
There we are. Now we can't hear those but this is a bat detector.
It is an instrument that brings the bat cries down into our world.
Those are echolocation cries.
That bat is now getting a picture of the world,
a picture of Bryson's face.
It's aiming at Brysons's neck,
towards his ear,
to provide an extra earring.
Thank you very much, Bryson
and the bat.
So, if the world looks different to a bee,
because of its ultraviolet vision,
how much more different must the world look to a bat
since it sees through its ears.
Now, when we say something like, "Flowers use bees for their purposes"
or "Bats use flies for their purposes",
what are we really saying?
What are flowers and bees,
hummingbirds and bats really for?
Well, this is a profound question and it's one that I want to turn to now.
I want to begin with a computer demonstration,
so I have first of all to insert this disc into here.
Virus Alert!!! Virus Alert!!!
This disc is infected.
Virus Alert!!! Virus Alert!!!
This disc is infected.
How do I get it out?
Right. Well, that, as you may have guessed, was in fact a fake,
but it might not have been.
Computer viruses are a real menace.
But what is a computer virus?
Well, it's just a program like any other.
It's written by somebody, it's a very simple program.
Unlike, say, a word processor that does something clever and sophisticated,
a virus program just does one thing.
It just says one thing, it says, "copy me and spread me around."
Now, because computer users are always spreading their discs around,
a program that says, "copy me" - "begin > copy me > end" -
when it passes through one computer and makes lots of copies,
the disc gets spread to other people and then it gets spread to other people.
And so, sooner or later, the whole country becomes filled
with discs with programs that all say "copy me".
It just works automatically
and without realizing what it's doing.
A pointless sort of program. Of course, it's pointless.
But it's irrelevant that it's pointless.
It spreads because it spreads because it spreads because it spreads.
Why shouldn't it spread,
since computers do exactly what they're told,
and a virus tells it to spread itself around.
The fact that it does nothing useful on the way, may even do harm,
is neither here nor there.
Real viruses that cause diseases like flu,
are very much the same kind of thing.
They're not written in computer language, they're written in DNA language,
but apart from that they're really very similar.
They also say "copy me",
they're also the bare minimum sort of program to get themselves copied.
There is one further difference,
which is that computer viruses are written by people
whereas DNA viruses arise by natural selection.
Those strings of DNA that just happen to mean the instruction "copy me",
those strings of DNA are the ones that will happen, that will tend to spread around.
Once again, they appear pointless to us
but, once again, what seems pointless to us
is not the point.
They're there because they're there because they're there because they're there.
Now, viruses, whether they're made of DNA or computer instructions,
have things made very cushy for them.
There is readymade copying machinery already in the world.
In the case of DNA viruses that readymade copying machinery is our cells.
In the case of computer viruses
it's computers aided by people carting discs around,
constituting a kind of paradise for a self-copying computer program.
But where does all this lovely copying machinery come from?
It doesn't just happen. It has to be made.
In the case of computer viruses it's made by humans.
In the case of DNA viruses it's the cells of other creatures.
And who makes those other creatures?
Those humans and elephants and hippos
whose cells make life so easy for viruses?
Well, the answer is that other self-copying DNA makes those creatures.
The DNA that belongs to us, us humans, us hippos, us elephants.
So what are big creatures like us and trees?
What are big creatures for? For whose benefit are they?
Well, from the viruses' point of view,
they think we're put in the world for viruses' benefit.
But that's not a very satisfactory answer
because it doesn't explain why we should bother to be there in the first place.
So, once again we have to shift our perspective, shift our point of view.
Let's go back to the computer viruses to look for an answer.
Writing a computer virus program is child's play.
Any fool can do it, which is why the silly little twerps who do have nothing to be proud of.
But imagine something like a computer virus,
which instead for having a readymade computer, already set up to obey its instructions,
had to start from scratch.
Now, that's more of a challenge.
It couldn't just say, "copy me" because there's nothing there to do the copying.
To be truly self-copying
in a world without readymade computing and duplicating machines handed to it on a plate,
our computer program would have to be a lot more complicated.
It would have to say:
"Make the machinery needed to copy me."
And before that it would have to say:
"Make the parts with which to make the machinery
that you need to copy me".
And before that, it would have to say:
"Gather raw material you need to make the parts, etc."
Now, this more elaborate program needs a name
and I'm going to call it "The Total Self-Copying Program."
The Total Self-Copying Program
has to have control over more than just an ordinary computer.
It's got to have a hand,
it's got to have something like an industrial robot to pick things up and manipulate them.
Because it's got to assemble something like itself.
Here's an industrial robot picking things up and dropping them into a box.
It's very similar to the kind of industrial robot that's used in the factories for making cars.
And if you can have a factory to make cars like this,
you could have a factory to make robots exactly like itself.
But that's not enough,
because this robot can only pick up the things that are within reach.
In order to run our Total Self-Copying Program, it's got to
be able to move around the world to pick up its raw materials.
It's got to have something like legs.
In fact it would have to have something like this.
This is Robug 2 from the Portsmouth Polytechnic.
It has four legs, it looks a bit like an insect.
It can climb up a vertical wall, as you see, because it's got sucker legs
and it's fairly clever about what it does if it finds an obstacle.
I'm going to try and tease it in a minute.
I'm going to try to put my hand under its back leg to see what it does.
Now, watch it.
It tries to find another place to put its leg there.
I think it's trying to kick me out of the way. Right. There we are.
Robots like this, in fact, direct descendants of this robot are actually very useful.
Because there are some places where humans dare not go,
like radioactive places, nuclear power stations,
and robots like this are actually in use to go into nuclear power stations,
for they don't mind the radioactivity,
and do repairs that humans would never dare to do.
This robot has four brains,
there, there, there and there.
And each one of those brains is controlling just the one leg.
So it's doing a fairly low level operation,
like working out what to do if I put my hand under the foot.
That controls the tactics of the individual legs
but the strategy of the whole robot
is at present being controlled by a human outside, through this cable.
This is the real robot.
The imaginary robot that we have been trying to talk about
would do something other than that.
I'm going to talk about it when it's stopped
and it now just reached the top
and I hate to think what would happen if it went on any higher.
So, thank you very much, Robug 2 and the Portsmouth Polytechnic.
Robug is a real robot
and it has been controlled by a human with the computer outside.
But we were using it to stand in for our imaginary robot.
And our imaginary robot would have its own onboard computer,
running a master program. And that master program would be
the self-copying program, it would say:
"Make a duplicate copy not only of the program,
but also of the apparatus necessary to duplicate the program."
And it would do that by walking around the world,
and it would have on its back the equivalent of
the industrial robot with the hand and the eye, that we saw in the film.
So it would march around the world, picking up the bits that it needs
to make a copy of itself.
The master program would say:
"Make a copy of the robot itself,
and feed the same Total Self-Copying Program
into the onboard computer."
A self-duplicating robot, like we've been imagining,
has never yet been built.
It was discussed, as an important theoretical possibility
by John von Neumann,
who could be called the father of the modern computer,
but it has never been built.
But wait a minute, what am I talking about?
What on Earth do I think this is?
Or this?
Or, indeed, me, or any of us?
These creatures, walking around the world...
Let's see whether we can make this one walk. There we are.
Now, think of that stick insect as just the same as the robot we've just been imagining.
Not the one we've just been seeing but the one we've just been imagining.
With its own onboard computer,
carrying around the instruction,
"walk around the world,
pick up raw materials, eat plant material,
use that plant material to make new robots just like this one."
And then those ones will go out into the world and they will wander around,
picking up food and they will be making new stick insects just like this one.
And in every case the object of the exercise
is to pass on the program that does the instructing.
Chameleon is the same, we are the same, and elephant
is the same.
This is fundamentally what a human or an elephant is.
An elephant is a huge digression
in a computer program written in DNA language.
Our DNA builds its own self-copying machinery.
This is what we are, we are machines, built by DNA,
whose purpose is to make more copies of the same DNA.
Well, that process is all very well once it starts,
but how did it start originally?
To answer that, we have to go back a very long way.
Very long time, more than 3 thousand million years,
perhaps as much as four thousand million years.
In those days the world was very different.
There was no life, no biology, only physics and chemistry.
Some people think that life begun
in what's been called the primeval soup.
A weak broth of simple, organic chemicals in the sea.
Nobody knows how it happened
but somehow,
without violating the laws of physics and chemistry,
a molecule arose that just happened
to have the property of self-copying.
And after that Darwinian evolution and life took off.
That may seem a bit of a stroke of luck
but it only had to happen once.
What's more, it may have happened on only one planet
out of a billion billion planets in the Universe.
So the sort of lucky event we're talking about as happening on this Earth
could be so rare
that the chances of its happening in any one year
somewhere in the Universe were only 1 in a billion billion billion.
That was enough luck for it to have happened.
Of course, if it did happen only on one planet anywhere in the Universe,
that planet has to be our planet, because here we are, talking about it.
But I think, probably the origin of life was a much more probable event than that
and therefore there probably is life on lots of planets around the Universe.
It's even been suggested that the origin of life may have been a rare event,
but having started on one planet, it then spread to other planets
in a process called "panspermia"
by the Swedish chemist Arrhenius.
And this is a fanciful reconstruction of panspermia by Karl Sims,
using the supercomputer, "The Connection Machine".
He doesn't really believe in panspermia but it's a nice animation anyway.
Here is a spore arriving from another planet on some distant world.
The spore swells and bursts,
and its genetic material, its equivalent to DNA,
is raining down on the planet.
And now each one of these units is going to start sprouting
what we shall call a plant, for want of a better word.
These plants, by the way, Karl Sims didn't invent:
he evolved them in his computer by a process very similar, though more elaborate,
to the biomorph program that some of you may have seen in an earlier lecture.
So, on this planet different kinds of plants are growing up. They're going through their growth cycle.
And at the end of the growth cycle
they're going to reproduce again
and the whole cycle of growth and reproduction is going to be renewed.
Here's a forest of plants,
all waiting to reproduce,
and here's the reproduction.
They're going to be shot out into space. Spores going off,
there they go.
And the cycle is renewed,
and the genetic information is sent off into distant space
to re-colonize other worlds.
Well, that was, of course, pure fantasy
but it does make some serious points about life anywhere in the Universe.
There will always be, I think, some kind of recurring life cycle
which begins from information capsules of some sort,
going through phases of growth and elaboration
and then, finally, returning again to the original information capsule phase.
On our planet the original, self-replicating machines
must have been a lot simpler than bacteria,
but bacteria are the nearest idea we can get to what they might have been like.
Here is a little view of bacteria reproducing.
and each individual one of those bacteria is actually fairly complicated.
There's the cell wall around it.
It's got chromosomes of genetic material.
It's not just a bag of fluid, it's got some complicated structure to it.
And that is, on Earth today,
the sort of minimal self-replicating machine as we now know them.
At some stage in the early history of life,
things like bacteria, we should probably call them bacteria,
ganged up together, came together and formed what we now call the eukaryotic cell.
That is just a long word. It means the kind of cell that we are made of.
Our cells are eukaryotic cells.
So are plant cells, so are the cells of fungi and protozoa.
It's now known, almost for certain, that the eukaryotic cell
was formed by the ganging up of bacteria,
perhaps two thousand million years ago.
This model of a eukaryotic cell
shows various bits, like these mitochondria in orange,
which are bacteria,
or are at least linearly descended from ancient bacteria.
And they go on reproducing all by themselves
as though they were separate bacteria.
Now, just as bacteria ganged up together
to form a cell like that,
so, cells like that ganged up together
to form larger units.
And under this microscope here
we have Volvox,
which is a fairly simple kind of organism
composed of gangs of cells, eukaryotic cells,
formed into a hollow sphere.
Would anybody like to come down and operate this microscope?
Yes, in the front row there.
What's your name? Katy
Have you ever used a microscope before, Katy? No. No, okay.
In there are some Volvox and they are great, big, green globular things.
And this is how you move the stage about.
Come here, then you can see.
If you move that one there, it moves that way. If you move this one here, it moves that way.
And I think I've found one for you. Try focusing there.
There we are. The other way, I think.
There we are, that's got it. Now are we seeing that right?
Good. Well done, Katy, thank you very much indeed.
What Katy has found is one Volvox.
It's a globe of a few thousand, perhaps one thousand cells,
and each one of those cells is a little, separate entity
with little hairs that beat, called cilia, round the edge
and the whole globe moves as if it was one organism.
Now, Volvox is not our ancestor. Volvox is a modern animal,
but it's possible that something like that
originally gave rise to our ancestors.
We are, after all, colonies of cells.
And this ganging up together of cells to form larger organisms
has proceeded to truly colossal lengths.
I said that an elephant was a huge digression on a "copy me" program,
and I really did mean huge.
Because whereas a Volvox has a few hundred or thousand cells,
an elephant is made of about a thousand trillion cells.
So if an elephant is a robot carrying its own blueprint about,
it's almost an unimaginably colossal robot.
Of course, it's not particularly colossal in absolute terms,
it's not big compared with a star,
but it's colossal compared with the DNA molecules that built it.
To understand this
imagine that we humans set ourselves the task of building a great
Trojan horse to carry ourselves about in.
Well, since we built it, the horse would look like a robot.
It would have steel plates riveted together and it would have television cameras for eyes.
But how big would it be?
Well, the answer is
that if this horse was built by us
to the same scale as we are built by our DNA,
or a real horse is built by its DNA,
then this horse would dwarf Mount Everest.
So this is building on a truly colossal scale.
The real living body, like a horse or like us,
manages to be so big compared with the genes that built it,
because it grows by a very different process
from the way a man-made machine would grow.
A man-made machine is put together by people swarming all over it and riveting on plates of steel.
But the special way of growing, that living things have, is very different.
It's called exponential growth
or you could call it growing by local doubling.
And here's how it works.
You start with a single cell, and I'm going to represent that
by a
coin on the right hand side of the chessboard.
That's one cell. Now, that one cell divides and produces two, just like itself.
And because those two just like itself,
they also have the property of being able to divide and producing four cells.
And each of those cells can divide and produce eight.
And you can see what we are doing. We are going on, doubling up
and what we're going to try to do is estimate how high the pile of coins would be,
if we went on, doubling up.
This animal is growing and growing and growing.
We've managed to fill one row of the chessboard
and now we will have to go on and the next one will be that high, and the next one would be that high,
and so on. We're growing this animal doubling up, doubling up, doubling up.
Now, how big would the pile of coins be
if we got to the other end of the chessboard, to the 64th square? How tall would it be?
I don't suppose you worked it out in your head
I worked it out beforehand, and it's fairly impressive.
The pile of coins on that square of the chessboard
would stretch to the star Alpha Centauri.
It would be about four light years away.
Well, that's exponential growth.
Could you bring in the blue whale, please Bryson?
Thank you very much.
Well, this wants to be a blue whale when it grows up.
And if it succeeded
it would be somewhere out there on the 57th square.
Because it only takes about 57 cell generations
in order to build a blue whale
which is made of about 100 thousand trillion cells.
Would anybody like to know how many cells they consist of?
Right. Yes.
We've got a computer program which just converts weight into cells by a rough calculation.
What's your name? Sam
Would you like to stand on the scales, please, Sam.
Gosh, those boots are going to weigh a lot on their own, aren't they?
Fifty three kilograms.
That is, Sam has approximately
74.2 trillion. Yes, 74.2 trillion cells,
but it would only take about 46 cell generations to make Sam.
Thank you very much.
Let's now try doing that with somebody a bit bigger.
Douglas, would you like to come out and have a -
Right. Let's have a look now.
110 kilograms, how does that look?
154 trillion, only 47 cell generations though.
Thank you very much, Douglas.
So only one more cell generation is needed
to make Douglas compared with making Sam.
And only another 10 cell generations are needed to make a blue whale.
Well, 46 or 47, or whatever it is, is, by the way, a minimum figure.
In fact, it would take a bit more than that,
because different bits of people are going on dividing for different lengths of time.
The liver cell is going on a bit longer, kidneys a bit shorter and so on.
So it isn't quite as simple as that.
But it does suggest to you how the body manages to control the shape that it is.
Because all it has to do is to change the number of cell divisions,
in order to change the shape of that bit of body, relative to other bits of body.
For instance,
in human evolution compared with our ancestor, Homo habilis,
the modern human chin is a fairly pointed object.
Homo habilis has a rather blunt chin.
So, in evolution of, humans the chin elongated. I'll just show you that.
There's my ancestor, Homo habilis,
and there's my chin for comparison.
So, in human evolution we had an elongation of the chin
compared with the rest of the head.
We had other changes, but compared to rest of the head the chin elongated.
Now, that would be a very easy trick to do with the local doubling form of growth,
because all you do is you slightly change the number of cell generations
that went into building the jawbone there, and you have that effect.
The remarkable thing is
that cell lineagesstop dividing
just when they're supposed to.
In such a way that all our bits are about the right size relative to our other bits.
Of course, in some cases, cell lineages don't stop growing when they should.
And when that happens, we call it cancer.
Well, building colossal bodies,
like us or like horses,
colossal by the standard of their DNA,
can be called gigatechnology.
Gigatechnology means the art of building things that are
at leasta billion times bigger than you are.
It's not a thing that human engineers have any experience of.
But humans are already talking about the opposite of gigatechnology,
which they call nanotechnology.
Just as giga means a billion,
nano means a billionth.
Nanotechnology therefore means engineering things
that are a billionth of your own size.
Nanotechnology is taken seriously by some serious scientists, not just madmen.
And this is what they visualize may happen in a not too distant future.
These are red blood corpuscles, this is purely imaginary,
these are the red blood corpuscles, there is a virus,
and here's a nanotechnology robot
that's been sent in order to skewer that virus.
If nanotechnology ever works
then it will have very revolutionary effects upon our lives.
Take surgery, for example.
Modern surgeons are highly skilled and they have,
what we think of as, a very delicate instruments like these
But listen to Eric Drexler
the American scientist who is the leading apostle of nanotechnology.
He says: "Modern scalpels and sutures are simply too coarse
for repairing capillaries, cells and molecules.
Consider delicate surgery from a cell's perspective.
A huge blade sweeps down, chopping blindly, past and through
the molecular machinery of a crowd of cells, slaughtering thousands."
Now he turns to the suture,
the needle which is used to sew up, the needle and thread which is used to sew up the wound:
"Later a great obelisk plunges through the divided crowd, dragging a cable
as wide as a freight train" -
that's American for a goods train -
"behind it, to rope the crowd together again.
From a cell's perspective even the most delicate surgery,
performed with exquisite knives and great skill, is still a butcher job.
Only the ability of cells to abandon their dead, regroup and multiply
makes healing possible.
Yet, as many paralyzed accident victims know too well,
not all tissues heal."
Nanotechnology holds out the prospect of building surgical instruments
small enough to be on the same scale as the cells.
And these instruments would be far too tiny to be controlled by a human surgeon's fingers.
If that's the width of a goods train,
then imagine how wide a surgeon fingers would be on the scale of cells.
A robot as small as that, capable of doing that,
would be a very wonderful thing to have,
but it's only one and there are millions
and millions of,say, red blood corpuscles to repair.
It would only work if the nanotechnology machines
themselves were cloned up,
were reproduced in exactly the same way as the red blood corpuscles are themselves.
Like this immunoglobulin molecule,
which is what a doctor might inject into you
in the thousands to protect you from hepatitis.
It only works because it's in your blood stream in thousands and thousands and thousands of copies.
And that's what nanotechnology depends upon.
This is not really nanotechnology because it's a biological object.
But that's the kind of thing that nanotechnology would look like.
Nanotechnology seems to us very strange, scarcely believable.
The idea of machines down there, at the level of atoms, seems a very alien world.
More strange than the life that is imagined on other planets
by science-fiction writers.
Nanotechnology seems to us something new, something in the future.
But actually, far from nanotechnology being new and alien, it's old.
Vastly older than we,
whose bodies belong in the world of big things.
It's we, big things, that are new, alien, strange and futuristic.
We are products of a flashy new gigatechnology.
Fundamentally life is based in the world of nanotechnology.
Now, you remember I said that cells are made of bacteria
and we are made of cells ganging up.
Well, there are also colonies of individual bodies,
social insects,
in which the entire colony can be thought of as one,
big, "copy me" digression.
This is a bivouac of army ants from South America.
This is a great sheet of millions of ants.
And the next one.
Here are just two ants, not army ants, a different species.
That one is the sister of that one.
They're both members of the same colony, they're both workers,
both are needed by the colony and so both are there,
even though they are such colossally different sizes.
This is what it's all about.
This worker here is feeding a young queen with wings.
Those wings are for carrying the DNA of the colony into the next generation.
The entire colony is one machine,
geared to passing its DNA on into the future.
This is the queen of a termite colony.
You see, she's huge, she's a gigantic egg-laying machine,
a walking egg-laying machine, except that she can't walk.
She is too big to walk. There's a king termite to show the same scale.
She's producing eggs to go on into the future.
These are honey-pot ants.
Their workers specialize to act as honey stores.
These are the armor plates of the body and they've been stretched apart
by this gigantic honey-pot here, filled with honey.
All that this does is to hang in the roof of the nest, like a light bulb
and when times are good it gets filled up with food.
When times are poor, the food is drawn out again.
This is a part of the machinery of the entire colony.
These colonies are very impressive in what they can achieve.
This is the nest of a South American fungus ant.
A great underground structure, a huge underground cavity.
There's a man to the same scale.
This is the sort of things that can be achieved
when you have colonies of individual bodies ganging up together.
And this is another example. These are weaver ants,
stitching up together leaves to make their nest.
There's one worker holding on to the junction there.
Here is a different view. Now we are going to see another worker with a larva
which is used as a tube of glue or silk,
and it stitches across, like, see how it's moving across with the larva.
There's another one there, moving across with the larva,
stitching up the junction between these two leaves.
They're making the nest for the entire colony.
This you could think of as the body of the colony,
which is there for the purpose of carrying on the genes that made them do it.
We began by asking, what flowers were for?
We considered various answers and eventually concluded that flowers
are for the same thing as everything else in the living kingdoms:
for spreading "copy me" programs about,
written in DNA language.
Flowers are for spreading around instructions for making flowers.
Bees are for spreading around instructions for making bees.
Elephants for spreading instructions for making elephants.
And birds for making more birds.
And macaw's colored feathers
are for spreading copies of instructions
for making more colored feathers.
And that works, because the colored feathers are an advertisement
that attracts macaws of the opposite sex.
So genes that make colored feathers
tend to get passed on to future generations
because they are an effective advertisement
to get mates
who like those colored feathers.
And you could say the same about wings. Wings, too, are tools
for spreading genetic instructions for making wings
into future generations of birds.
They work by saving the lives of birds that have good wings
and so they are good at flying,
good at catching food, good at avoiding being eaten.
So genes that make good wings get passed on
and that's why most birds have wings that work.
So, thank you very much, macaw.
Plants don't have wings.
Plants can't fly.
But from the plant's point of view, it doesn't need wings
since it can borrow the bees and butterflies and hummingbirds' wings.
But now let's shift our perspective
and look at it from the point of view of the plant DNA.
From the point of view of the plant DNA
the bees' wings might as well be plant wings.
The bees' wings are organs of flight
that carry the plant's genes about.
Just as a macaw's wings are organs of flight
that carry macaw's genes about.
And we can say the same about the colors.
Flowers use bright colors in very much the same way
as macaws use their bright colors.
Both kinds of color are advertisements,
both are used to attract winged-gene vehicles.
In one case those winged-gene vehicles are female macaws,
in the other case they are bees.
But in both cases the result of the attraction
is that genes are carried about.
The macaws mate,
so the genes that made that the male have attractive feathers
are carried off in the female's body.
The bee gets dusted with pollen from a flower.
So the genes that made the flower attractive to the bee are carried off
on the body of the bee into the future, into future generations.
So if you look at them in the right way,
bees' wings can really be called
plant wings.
Now, that really is a different way of looking at things, isn't it?
A strange, and unfamiliar way.
Yet it is a way that makes perfect sense when you think about it.
A way of looking, which matches the strange
otherworldliness of the ultraviolet garden.
In the last of these five lectures, we shall be coming on to the human brain
and how it managed to get so big.
Thank you very much.
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