Today's lecture is about the problem of design.
So the obvious place to begin is with things
that are clearly not designed.
This is just a plain, ordinary stone.
The laws of physics, left on their own, will produce something like that.
They can also produce something like this,
which looks superficially like a boot,
but the resemblance is purely accidental,
it means absolutely nothing.
Nor does the resemblance of this to a fish mean anything,
nor the resemblance of that to a duck's head.
This is slightly more interesting
but it is still purely fortuitous.
It looks like an egg and inside is a little dummy embryo,
but again, it is pure luck that is just produced by physics alone.
That is also true of these rather beautiful looking crystals.
But this is rather more interesting
because crystals are what you get
when atoms, all of the same kind,
are allowed to stack up together in a way that they "want to do".
This is a different kind of crystal, a desert rose.
Almost looks as if it might have been made by a jeweler.
But all these objects are fortuitous.
None of them is designed.
All the stones belong in the category I am going to call
"simple."
The same is true of clouds and stars.
Nobody designed them,
they came to be the way they are
by the simple consequences of unaided laws of physics.
They're examples of the way things just happen to be.
Now we are ready to look at some objects
that really are designed.
This microscope,
nobody could possibly mistake that
for an object which just happens to be the way it is.
Everything about it has "design" written all over it.
It has a long tube
to look down, a lens this end, another lens that end,
a mirror to reflect light up through the tube,
knobs to change the focus,
other knobs to move the slide
from side to side and back and forth.
Even the knobs themselves are roughened
to make them easier to grip.
A designed object.
The same is true of this calculating machine,
the same is true of this watch.
There are some slightly more difficult cases.
These flint arrowheads.
There is not much doubt that they are designed.
They are shaped in a way you would'nt normally expect
a stone on the beach to be shaped.
This one is a bit more doubtful.
Experts tell us, archaeologists tell us,
that that is a designed object,
that some primitive people did indeed shape that
for a purpose. I'm prepared to believe them.
But that is a slightly more difficult case.
Never mind about them.
There are plenty of objects which are absolutely, obviously designed
What do they all have in common, these designed objects?
They are all good for some purpose, and they couldn't have come to be the way they are by luck.
The microscope is obviously very good at its purpose
of greatly magnifying objects
and most certainly it couldn't have come about by luck.
If you take a lot of atoms and shake them up at random
then you may get a crystal
but you will not in a billion billion billion years get a microscope.
This is a guzunder, so called because it goes under,
and it clearly has a more humble purpose then the microscope,
but it works very well for its purpose, it's clearly designed.
Once we realize what its purpose is,
which is to hold water,
we can come up with crude measure of how good it is.
We can measure, we can say the cost of the pot
is the amount of clay that goes into it
and the benefit of it is amount of water that it holds.
And so its efficiency is the ratio of the weight of water that it holds
to the weight of clay that goes into making it.
We compare it with this pot
which is not made by man
but is a natural stone.
It also would hold water but it would not hold very much water
for the amount of stone that goes into it.
Its efficiency ratio is not very high
and indeed it is not a designed object.
It is a simple object which just happened to be.
So we have divided these objects into those that are designed
and those that I'm calling "simple."
But now I want to introduce
a large and very important category of objects
that are certainly not simple
and I shall argue that they are not designed.
But they look overwhelmingly and compellingly as though they were designed.
And I'm going to call them "designoid" objects.
Designoid objects look designed
but they actually got their designed look
from a very different process
which we will come onto later.
You may find it hard at this stage to believe
that designoid objects are not designed but just wait.
So, let's have our first designoid object.
This is Andrew, isn't it? And what's the snake called?
Squeeze.
The snake is called Squeeze.
It's a boa constrictor and it is a magnificent example of a designoid object.
It looks as though it has been beautifully designed for a purpose.
One of those purposes is swallowing prey
which look very much too large for it to swallow.
And one of the ways in which it achieves this is by the head -
The bones of the head, the bones of the skull are capable of detaching,
coming apart, under the skin, of course,
so that the head swells to a huge size relatively to what it starts.
And there is a great gaping maw
which is capable then of swallowing very much larger prey than you'd think.
The skin here is a beautiful mottled color
which you can imagine would be
very, very highly camouflaged in a forest.
The snake has lost its legs.
Losing legs is a very common thing among reptiles.
There are many lines of evolution of reptiles which have lost their legs.
What the boa constrictor is best at is throttling its prey
and I think both Andrew and Squeeze deserve a round of applause.
Thank you very much.
Just looking at the outside of Squeeze gives us no real idea at all
of what an extraordinarily complicated structure
he and all other living things are.
A living thing like Squeeze is not just
more complicated than the microscope.
It is billions of times more complicated than the microscope.
Let's come back to pots.
We have seen a designed pot
and we have seen a simple, accidental pot.
Now, here is a designoid pot.
This is a pitcher plant.
Here you see the individual pitchers.
There is an enlargement.
They are filled with water and they are traps for insects.
Insects fall into the trap and drown.
This is how a pitcher begins,
this is the next stage in development.
It begins as a leaf.
You see the hole just beginning to form.
This is a young pitcher
and then we are going to see the full pitcher.
There is a fly climbing up it.
There is a slippery area at the top.
The fly is down, into the water.
It's now going to drown and in due course its products will be digested by the plant.
Here is a live pitcher plant.
Here is one of its pitchers.
You can see the little lid over it.
There is the slip zone there, and inside is the water.
It appears to be a well designed object,
a well designed pot.
If we were to do our cost/benefit ratio,
our measure of the amount of water that it holds
over the weight of the plant material itself,
we would find that it is a very efficient pot indeed.
But we would also find that if we looked inside, cut sections of it,
it would have a very complicated structure.
This is the inside of a single cell of a pitcher plant
through an electron microscope.
And you can see the complexity of it.
What is more interesting is that this internal structure is very well fitted
to make a lot of oxygen and secrete it into the water of the pitcher.
And this has a very useful effect
because in the water of the pitcher are living
a motley crew of little maggots and other insects.
Now, what are they doing?
Well, it is all very well eating insects,
like a pitcher plant does,
but a plant doesn't have any teeth
and it is difficult to eat insects if you haven't got teeth.
So what the pitcher plant in effect does is to borrow the teeth of these maggots in its pitcher.
For what the maggots do is they eat the prey that fall into the pitcher
and then their excretory products are what are finally absorbed by the pitcher plant.
So really the pitcher plant is just getting
the same thing as any other plant gets when it eats manure, in effect.
But what the pitcher plant is doing is sequestering for itself a private supply of manure
by luring insects and by supplying
the maggots that live in the pot with a nice, oxygen rich, fresh water atmosphere
which otherwise they wouldn't like to live in.
Here is another sort of pot, a designoid pot.
This is made by a trapdoor spider, you see the trapdoor at the top.
The spider lives inside.
And another one here.
This is the pot of a potter wasp.
That's a solitary wasp, not like the social wasps
which build combs, more like this honey comb here.
The potter wasp, female, builds a pot like that out of mud
and lays her eggs in it and then the larvae grows up inside the pot.
Look how beautifully it resembles this designed pot.
This is a truly designed pot,
made by somebody in Mexico.
See how similar it is to the pot made by the potter wasp.
Yet another animal pot.
This was made by a mason bee.
Exquisite little thing.
It is used for the same purpose as a potter wasp's pot
buy has a different structure.
It is just like a house built by humans.
These are little individual stones which the bee, the female bee, has gathered and has cemented together
to build up this delightful pot structure.
And the story doesn't end there
because we can only see one pot,
but underneath here are four more pots.
And they've been carefully covered up by the bee
who has gone to the river and gathered clay to cover over her pots.
The clay is exactly the same color and texture as the rock
on which the pot is placed,
so that bee's predators,
the predators who might come and eat larvae out of the pot,
would never know in a million years that there were any pots under there.
Here is another beautiful example of designoid architecture.
These gigantic megaliths, like Avebury or Stonehenge,
are built by the compass termite of Australia.
They are huge structures, like blocks of flats.
Certainly, on termite's scale, they are like blocks of flats.
They are all pointing exactly north-south,
which is another very cunning feature
because that means that they get the morning sun on one side
and they get the evening sun on the other,
so they get nicely warmed up in the cool parts of the day.
But in the hot part of the day,
the midday sun hits them end on,
and so they don't heat up too much,
which is why all these termite nests, they're called compass termites,
when you are in the desert, you can always tell which direction
is north-south by looking for a compass termites' nest.
Even larger is this other kind of termites' nest.
You can see the scale there.
This is a most colossal structure.
The Austrian ethologist, Karl von Frisch, remarked
that if humans built structures on the same scale as termites do
the structures would be four times as high as the Empire State Building.
So termites are very, very impressive architects.
These designoid objects are very impressive indeed.
We are switching now from objects which are apparently designed by animals
to the design of animals themselves.
The apparent design of animals themselves.
And I am beginning with camouflage.
If you are walking through the desert you will probably think,
to casual look, that that was a stone.
But it's not a stone, it's a grasshopper.
It just looks like a stone and it gets protection from looking like a stone.
And the next example.
This looks to me exactly like seaweed.
It is one of my favorite of all designoid objects.
It is, in fact, a fish.
It's a seahorse.
There's its head, there is its neck, there's its body.
And these objects sticking out here are parts of the fish's body.
But anybody would think that they were parts of a seaweed.
They look exactly like parts of a seaweed,
and the seahorse hides among seaweed of just the right type.
It is almost perfectly camouflaged.
And we have a few more examples.
This is a film of a leaf insect.
There's the shield over the thorax, there's the head.
Here come the wings,
and when it isn't moving, perhaps even when it is moving,
it looks exactly like leaves.
It's just flown off.
Here is another.
The thing looks just like a plant.
Turns out to be a green snake.
And this you would think was a plant, with a bud on the end,
a long, green stem. More buds.
Only when we get to the front end
do we just about spot that it has an eye, antennae and legs.
It is, in fact, a stick insect.
Look at these leaves here.
Autumn leaves.
Look at the vein up the middle of the leaves.
Look at the veins on either side.
Look at the little splotches of dark colored mold on the leaves.
But those are not leaves.
Those are butterflies.
Look, you can just see the body, there, there, there, there.
That's what these butterflies look like when they open their wings.
This is what they look like on the underside of the wings.
And they normally sit with the wings folded
so that you only see the underside of the wings.
And you are very hard put to it to see that they are not dead leaves.
Only when they open their wings you get this flash of brilliant coloration.
Camouflaged animals resemble inedible objects.
Designoid objects sometimes resemble other designoid objects for other reasons.
Because they are doing the same job.
And this is called "convergent evolution."
This is an ordinary hedgehog.
That is nothing whatever to do with a hedgehog
but superficially it looks like it.
This is a spiny anteater.
It is a mammal
but you might say, only just a mammal.
It's an egg laying mammal, a very primitive mammal
from Australia and New Guinea.
As a matter of fact its way of life is not that close to a hedgehog's way of life
This is an ant eater whereas hedgehogs eat more general things: insects and worms and things.
But both of them gain protection from having spiny skins.
And so they both superficially look very alike.
An example of convergent evolution.
An even better example of convergent evolution
is the so called marsupial wolf.
Now, if you saw that going along on a lead down the street you would think it was a dog.
A slightly odd sort of dog, perhaps.
There are not many dogs that have quite that structure at the tail end.
But you would think that that would not really be out of place at Crofts.
But this is not a dog.
It has nothing whatever to do with dogs.
This is a marsupial.
It's much more closely related to kangaroos and wombats and koalas.
It's now, most unfortunately, extinct.
Only fairly recently extinct. It went extinct this century in Tasmania.
It went extinct some thousands of years ago on the mainland of Australia.
And the reason it looks so like a dog
is that it does the same job as a dog
or did the same job as a dog.
It ran and hunted prey in the same sort of way as a dog does.
And that is why it has the same shape as a dog.
The structure inside also resembles that of a dog.
This is a dog skull.
And this is the skull of the Tasmanian wolf.
It's a bit larger
but the size of a skull would depend on how big the dog is
And we could easily get a bigger dog's skull than this.
The only reliable way to tell that this is a marsupial and not a real dog
is if you look underneath.
Those two holes in the palate there
give the game away. Those are the telltale clues
that tell us that this is a marsupial and not a real dog.
Real dog doesn't have the same kind of holes there.
Well, that's convergent evolution among designoid objects.
Designed objects, too, sometimes resemble each other
because they are doing the same job.
Two airplanes closely resemble one another
not because of industrial espionage not because of imitation
but because the wind tunnel is a great leveler of differences.
These planes have both been designed for the same purpose
and when you design planes for the same purpose of flying very fast through air
and carrying a large payload of passengers,
those planes are going to come out looking pretty similar,
in just the same way as the dog and the marsupial wolf come out looking similar.
So we have seen convergence between two designoid objects
and we have seen convergence between two designed objects.
How about convergence between designed and designoid objects?
Well, here is a camera, which is a designed object,
and here is an eye, a designoid object.
They both do something very similar.
They both have a lens at the front
which focuses an image on a light sensitive surface at the back.
In the eye it is called the retina: in the camera it is a film.
There are detailed resemblances as well.
Both of them have an iris diaphragm.
It opens and closes to regulate the amount of light that goes in.
In an automatic camera the amount of light that goes in and out is automatically regulated by a light meter,
which when it gets brighter
closes down the hole, when it gets darker, opens up the hole.
And the human eye also has an automatic light meter.
I wonder whether we could have a volunteer?
Right. In the front row there. Yes. Right.
What is your name?
Gillian.
Would you like to take your glasses off, Gillian.
Thank you. Come and sit down here, please.
Now, what you do is look into the camera there
and they are going to take a picture of your eye, of your iris.
What I'm going to do is I'm going to shine this light into the other eye.
And I hope it won't be too bright.
And what we hope to see is that your iris will contract when I shine the light in.
So, look into the camera and I'm going to shine the light.
Did you see it contract?
Look into the camera.
There, it contracts. Did you see it?
I think it's best perhaps to look into the eye that I'm actually shining the light into.
No, not you.
Look into the camera. Is it too bright for you?
No, okay, look into the camera.
There it goes. Did you see it?
Thank you very much, Gillian.
And there are numerous other examples of living things
being exactly the way a human engineer would have designed them.
I hope that's enough to convince you
that there's something special about living objects.
They look designed,
they look overwhelmingly as though they're designed.
I call them "designoid"
and I ask you to accept this different title.
But it is terribly, terribly tempting to use the word "designed".
Time and again I have to bite my tongue and stop myself saying,
for example, that this swift is designed
for rapid, high speed, highly maneuverable flight.
And, as a matter of fact, when talking to other biologists
we none of us bother
to bite our tongues, we just use the word "designed".
But I've told you that they're actually not designed
and coined a special word "designoid"
and I said that there is a special process
that brings designoid objects into existence
and gives them their apparently designed look.
What is that special process?
The answer to this question was discovered surprisingly recently,
in the middle of the last century.
One of the greatest discoveries of all time,
made by one of the greatest scientists of all time - Charles Robert Darwin.
A surprisingly long time after he discovered
his principle of evolution by natural selection,
he wrote this famous book, The Origin of Species.
This is an original first edition, inscribed by the author.
Very valuable.
Darwin began his argument on natural selection,
he introduced it, in terms of another process called artificial selection
or selective breeding.
All these vegetables here
have been bred
by human breeders for different food purposes.
There is an ordinary cabbage, cauliflower,
red cabbage, broccoli, Brussels sprouts, kohlrabi.
Each of these different sorts of plants has emphasized
a different aspect of the original wild ancestor - the wild cabbage.
So kohlrabi for example has a greatly swollen stem.
Cauliflower has a greatly enlarged flower.
So does broccoli but in a different way.
They're all descended over the last couple of thousand years
from the same wild ancestor, the wild cabbage.
Now that's the wild cabbage as grown by Bryson.
Bryson has many virtues but green fingers are not among them.
Nevertheless, if you were to take this home
and grow it for a little while,
water it properly, look after it, it would grow up into a wild cabbage.
It wouldn't look very like any of those cabbages.
That's the point I'm making: they've all come from the wild cabbage
but they are all very different from the wild cabbage.
All the breeds of domestic dogs have been bred from
the same common ancestor, namely a wolf.
Those dogs look terribly different.
You would never think they were the members of the same species
but they all, in fact, come from the same species, a wolf.
Now, what is this artificial selection, this selective breeding
that enables you to go from a wolf to something like that
or that or that?
Well, I'll tell you very, very briefly what it is.
You start with the ancestor, the wolf.
And I am going to suppose for simplicity
that everybody on this side of the room is going to imagine breeding
for smaller and smaller wolves,
and everybody that side is going to imagine breeding
for larger and larger wolves.
So in every litter of wolves that we get,
if you are on the small side - what you do is to look out
for those individual puppies that are a bit smaller than the average
Those are the ones that you breed from,
and on this side you breed from the larger ones.
Now, it is going to take a long time,
generation after generation.
You mate together relatively small dogs, wolves.
And on this side you mate together relatively large wolves.
And after many generations, perhaps hundreds, perhaps thousands of generations,
perhaps a couple of thousand years of this selective breeding,
because there are genes involved in controlling the differences between the cubs,
eventually you may end up with something like
...what I hope is now going to come in.
That would be the end product of breeding for larger and larger sized wolves.
That would be something like the original
ancestor that you started from,
and that would be the end product of breeding for smaller and smaller wolves.
What are their names?
Jemima and Wilf
Jemima is a smooth coat Chihuahua. Wilf is a rough coat Chihuahua
and both of them comparatively recently are descended from a wild wolf.
What's her name?
Sequin
This is Sequin, a German shepherd
and I think we could say that Sequin
is the one who most resembles the ancestral wolf.
And this is Archie, that's a fine name,
Archie, a great Dane,
and he is what you get from breeding for larger and larger size
but they all descended from a wolf,
they're all cousins of one another and Sequin is showing great interest.
Thank you very much indeed. Thank you.
Charles Darwin was very interested in dogs.
He was also very interested in pigeons.
Thank you.
You're on my notes, pigeon.
This is a Marchenero cropper.
It's a pigeon which has been bred by artificial selection
from the wild rock dove
and in this case it has been bred for the thickness of feathers and for size of crop.
You see the great big crop at the front
which is blowing up like
that and see how big the feathers are.
In the cage here - we didn't quite trust these ones to be let out.
We trust this one.
This is a domestic flight pigeon and you see how it has been bred
for this curious little ruff round the back of the neck.
And also the red ring around the eye.
The other one is an English short-faced tumbler pigeon.
You see the extraordinary short face and the tiny small beak.
That again is a product of artificial selection,
just like in the case of dogs and cabbages.
The beak is so short in the case of English short-faced tumbler
this breed is no longer capable of feeding its own young.
And so the only way that breed can be reared
is by its babies being reared by pigeons of another breed.
That sort of thing often happens, by the way, with artificial selection.
It's true of bulldogs.
You probably know that the bulldog breed of dog has a head that is so big
that it can't be born
and the only way a bulldog can be born is by Cesarean section.
So the entire breed depends upon humanity to keep it going.
If we went extinct, bulldog would go extinct.
Artificial selection,
the process that produces these dogs, these pigeons, and these cabbages,
is too slow for us to see during the course of one lecture.
But we can imitate it on a computer.
And I'm going to do it with a program called "arthromorphs."
These are arthromorphs.
This is the parent arthromorph
and round the edge of it are eight child arthromorphs.
They resemble the parent very closely
but there may be a genetic change, a mutation,
a random genetic change,
as you go from parent to child.
So that one, for example, has longer legs,
that one has got legs up instead of down.
The way you breed arthromorphs - Could I have a volunteer -
My goodness.
Right. Yes. Yes.
Have you ever used a computer with a mouse?
Yes.
What you do is you choose the one you want to breed from
and just click it once.
So you are going for the long legged one, I think.
Click it.
It goes to the center and becomes the parent of the next generation.
Now you see, all in the next generation have longer legs.
What's your name, by the way?
Lawrence.
Lawrence seems to be breeding for longer legs.
I wonder if he is going to continue that.
That's right. Keep going. Don't wait for me. Just keep on breeding.
Okay, Lawrence likes long legs and they are getting longer and longer.
Okay.
What I said was that these creatures have genes which are going from parent to child.
What would I mean by talking about genes in a computer?
In a computer, of course, genes would just be numbers.
They are not real genes, they are not made of DNA,
but nevertheless they are genes in the sense that they are what go through from generation to generation.
There is no sex in these creatures, by the way,
these are all reproducing asexually,
like stick insects and like aphids.
Carry on.
Breed as fast as you can to get through a lot of generations.
So what we are seeing now, what Lawrence is doing,
is artificial selection,
just like our ancestors did
with dogs and pigeons.
But he is managing to achieve in a couple of minutes
what would have taken several centuries for our ancestors to have achieved.
What are you going for, Lawrence?
You're trying to get a lot of zigzags in the legs, are you?
All right. Perhaps we better proceed now,
so thank you very much indeed, Lawrence.
I think that we are all convinced by now that artificial selection works.
We've seen the results of it in dogs, cabbages and pigeons,
and we have seen it happening before our eyes in the computer arthromorphs.
But this is just artificial selection.
We began talking about artificial selection
because we're really interested in natural selection.
Natural selection is like artificial selection
except that instead of humans doing the choosing, nature does the choosing.
Of all the puppies in a litter, wolf cubs in a litter,
instead of our choosing which one shall breed,
what happens is that nature chooses which one shall breed.
The ones that have
what it takes to survive will be the ones that breed, automatically chosen.
The ones that are good at running fast,
the ones whose legs are not too short and not too long.
The ones whose teeth are not too blunt and not too sharp,
because if they are too sharp they might break easily.
Natural selection,
nature, is constantly choosing
which individual shall live,
which individual shall breed.
And the result, after many generations of natural selection,
is much the same as the result
after many generations of artificial selection.
So what would it take to change
the arthromorph program
so that it simulated natural selection instead of artificial selection?
Because at present the arthromorphs are just being chosen by the eyes of a human.
Could we somehow make the computer do its own choosing?
Choosing on the basis of quality of arthromorphs.
The trouble is, it's not easy to judge
what quality in a arthromorph might mean,
because these arthromorphs are living in a very strange environment:
a two dimensional computer screen.
They don't have a real world in which to live,
they don't have predators, they don't have prey,
they don't have food they've got to catch.
Perhaps we'd do better if we made a computer model of a two dimensional designoid object.
Like a spider web.
Now if we could have the lights down,
I think we might be able to see -
There is a spider in the middle
of its web and that, I think, shows quite nicely.
Good.
You know what the spider web is for:
it is for catching flies and other prey.
It is a net and it works in two dimensions.
We would've liked to actually shown you a spider building its web
but this one seems to be pretty satisfied with the web it has already got.
So what I'm going to do instead is to show you a computer reconstruction
of a spider's movements while it builds a web. Do watch carefully.
This is rather speeded up.
Can we have that more slowly now, Peter?
What the spider is now doing is the radii of the web.
Now it's doing the structural spiral,
which is a kind of scaffolding.
And now it is doing the sticky spiral
which is the bit that actually does the business of catching the flies.
Let's have it once more, slowly.
There are the radii.
Now it's doing the scaffolding.
And now it is doing the real sticky spiral.
What we've seen there is not actually a picture of a web itself.
That's a picture of the movements of a spider
that were recorded on a particular day. That's a particular spider on a particular day.
Its movement were all fed into the computer and now the computer is playing it back to us.
But that's just a recording of the web of a real, particular spider.
In order to do our trick of making an arthromorph-like program out of spider webs
we've got to make the computer behave like a spider.
And this is the program written by Peter Fuchs who is next door,
controlling the computer.
And what his program does
is to make the computer build the web
as if it was a spider.
So the computer is holding in its little head the rules,
that we know something about, of how a spider builds a web.
So the computer does the radii like that. It does the spiral like that.
Just as in the case of the arthromorphs,
what Peter has done is to make the building rules of the computer spider, under genetic control.
There are genes in the computer, just as they were for the arthromorphs,
and just as they were for the arthromorphs, the genes are simply numbers.
That is the parent web,
these are the daughter webs more strictly,
that's the web that was build by the parent spider,
these are the webs that were built by the daughter spiders.
To begin with we can treat this just as if it was
an arthromorph program.
So we want another volunteer,
let's have a girl this time.
Yes, please.
What's your name?
Ursula.
Ursula,
Come here, Ursula, please.
have you ever used a computer with a mouse?
Yes.
Yes, good.
So this time is just like the other one only
you have to click twice instead of once
to choose which one you think is the best web.
Okay, now that web has gone up to the top there.
That's now become the parent.
And here are the daughter webs that are being drawn.
And now you can choose another one, another generation.
So you see we're doing just the same as we did for the arthromorphs
but now we have got spider webs coming.
But the point we were going to go for
was not artificial selection.
The whole point of doing this with spider's web is to do something like natural selection.
And to do that
we simply make the computer work out
how good each web would be at catching flies.
And we can do that
because, unlike the case of the arthromorphs,
the webs are two dimensional structures
and we know what they are for. They're for catching flies.
So the benefit is simply going to be the number of flies caught
and the cost we can calculate
because the webs are made of silk. as the amount of silk used,
So the cost of a web is the amount of silk
used and the benefit is the flies.
If you would like to stop now, Ursula. Thank you very much.
Now, we no longer have a human selector,
we now have the flies doing the selecting.
So the flies are going to hit the web
and Peter gets to start it up again.
Now we've got a new generation of webs being built
and we are now going to see the flies hitting the webs.
There come the flies. Flies again.
Now the computer is going to calculate
which of the webs is best at catching flies and it's that one that has gone dark.
So that one will now become the parent of a next generation.
And now, once again.
The webs are being built, the child webs are being built.
Once again. the flies will come, the computer will measure which one of them is the best.
There it is.
And that becomes the parent of the next generation.
It wouldn't take very long for us to see the evolution
starting from nowhere at all and going to a nice
web that works very well,
but we haven't quite got time for it.
So instead, what we did, was to let the computer run all night, all last night,
and we've got a "fossil record" of all the webs that were built during that time.
This was the starting web,
the thing that started at the beginning of the night's run
and then, every 20 generations,
we have a printout of the shape of the web.
So you see, we start with almost no spiral at all,
and you could imagine the fly just whizzing straight through and not getting caught.
But then natural selection in the computer
led to a gradual improvement in the web,
more and more spiral, more and more flies caught,
and so evolution went in the direction of a nice full web
with a nice full spiral like that, catching lots of flies.
That all went on in the computer last night,
very fast, telescoping into one night
what would have taken thousands of years, perhaps millions of years in nature.
In nature, the successful and the unsuccessful webs
would not, of course, be judged by the computer doing a calculation,
about how many flies would have been caught - would be expected to be caught -
the webs would be judged automatically and without any thought by the flies themselves.
The flies themselves that fly into webs,
thereby choosing webs for breeding.
The flies don't know they're choosing the webs for breeding.
They don't particularly want to fly into the webs,
but nevertheless the consequence of their inadvertently flying into webs
is, that the spider that built the successful web,
is a spider that is more likely to breed
and therefore more likely to pass on the genes for building that sort of web.
So, as the generations go by,
webs get better and better and better,
just as they did in the computer in our overnight run.
That's natural selection in the case of spider webs and exactly the same principle works
for every living creature, for the bodies of every living creature.
Every lion and tiger, every camel,
every dog,
every human, every giraffe.
They all have evolved by the same process
of evolution by natural selection.
So the Darwinian view
is that designoid objects are not designed at all.
They have evolved by natural selection.
The most popular alternative
to the Darwinian view is called "creationism."
Creationists believe that designoid objects are really designed objects.
The only difference is that whereas
these designed objects were designed by humans,
these designed objects were designed by a divine creator.
And the favorite argument of
creationists is the so called "argument from design,"
which was most famously expressed by Archdeacon William Paley,
in 1802, in the book, Natural Theology.
Paley begins his book:
"In crossing a heath,
suppose I pitched my foot against a stone,
and were to ask how the stone came to be there;
I might possibly answer that, for anything I knew to the contrary,
it had lain there forever."
In other words, the stone is the kind of object
which had always been there and doesn't need any special kind of explanation.
But, Paley goes on:
What if I accidentally kicked a watch?
The watch, I open it up, I see the mechanism, I see the cogwheels, and the springs,
everything about it looks designed.
It had to have a designer.
It had to have a watchmaker.
And if the watch had to have a watchmaker,
then how much more - Paley argued -
must these objects, these living objects,
including ourselves, have had a "Divine watchmaker."
For Paley it follows, as clearly
as the night follows the day,
that just as the watch had to have a designer,
so do we have to have a designer.
But, of course, just to show that animals and plants look as though they have got a designer
begs the question. I've spent much of this lecture trying to persuade you
that animals and plants look as though they've got a designer.
But I've spent the other half of the lecture showing you
that there's another very good alternative explanation
for why they look as though they had a designer,
namely, natural selection.
Well, Paley, of course, lived before Darwin,
so he couldn't be expected to know about the alternative.
Nevertheless, it was even without knowing about Darwin, it was possible
back in the 18th century to know
that Paley's argument was a pretty bad argument.
And this was pointed out by David Hume,
one of the greatest philosophers of all time.
Hume made the point
that the argument from design,
which was Paley's argument,
is that things like elephants and humans are too complicated
to have come about by chance. They have many parts, just like a watch,
too complicated to come about by chance.
A designer, a watchmaker, an engineer
is certainly one way
in which these objects could come about.
But a watchmaker or a designer or an engineer,
if he is to be any good as a watchmaker or an engineer,
must be pretty complicated object himself.
It's no good just postulating a designer
because a designer is just the very kind of thing,
just the very kind of complicated, ordered thing,
that seems to need the very kind of explanation that we are searching for.
If a human is too complicated
to have come about by luck
or if a swift is too complicated to have come about by luck
then a thousand times more so any being capable of creating humans
must be too complicated to have come about by luck.
The argument from design
certainly proves that living things couldn't have come about by chance,
but by the same token, and even more strongly, it shows
that the divine creator couldn't have just come about either.
The creator would have needed an even bigger creator, and so on.
The argument from design is a powerful seeming argument
and it powerfully shoots itself in the foot.
The Darwinian argument of evolution by natural selection, of course, doesn't suffer from this problem.
The Darwinian argument
does not explain things as due to chance.
Chance, in form of random genetic mutations, comes into it,
but by far the most important part of the Darwinian explanation
is the non-random process of natural selection.
There's another, rather interesting, little curiosity
which is that natural objects, designoid objects, have imperfections
which you wouldn't expect to get
in objects which were designed by a real designer.
This is a flatfish, a halibut.
Its ancestors once
swam normally in the water like a normal fish does, like that.
But the ancestors of the halibut settled down on the bottom of the sea,
one side down.
They lie on the bottom of the sea,
and now a modern flatfish moves along like that.
You have probably seen them doing it.
But when it did that the ancestor found that one of its eyes was looking straight into the sand.
Only the other one was looking up.
And so, gradually in evolution,
the other eye, the one that was looking into the sand,
migrated round the side of the head and came up to the top.
With the result that the skull of the halibut
is now an extremely distorted object.
It's like a sort of Picasso painting of a fish. It's got its two eyes on one side.
Anybody who was going to design a flatfish wouldn't do it that way.
You would do it like a skate, which is another kind of shark, which is also a flatfish.
And it flattened itself, its ancestors flattened itself, by going on to its belly
so that both its eyes were looking upwards and it had no need
to do any kind of distortion.
But by some kind of historical accident the ancestors of the halibut
and the sole and the plaice
all did it by lying on their side
and that meant that they had this distortion.
So this is an imperfection in design.
Which is just the kind of thing you'd expect to see
if these creatures had evolved,
but is very much not the kind of thing you'd expect to see
if these creatures had been created.
Evolution starts from simple beginnings.
The starting point of evolution
is the kind of thing we see here.
Something like crystals, something at least as simple as crystals
And it builds upon simplicity
to get towards complexity.
We start with a simple foundation,
simple things are easy to understand. We do not have to start
with a complicated thing,
like a creator.
On this simple foundation are built designoid objects by natural selection.
And only when we have designoid objects with brains
as big as human brains,
does design finally emerge.
But why do I say just humans for design?
Isn't it rather unfair
to the wasps that built
these pots, and bees and spiders and things,
rather unfair to this ovenbird that built that mud nest
or that nest of social wasps,
which is very similar to that convergently,
also built of mud?
Why do I use the word "designed" only for human creations
and not for the manufactures of these animals?
The difference is that human designs
get their goodness and efficiency
from conscious human foresight.
Wasp pots and ovenbird nests
get their efficiency directly from natural selection
by a kind of hindsight rather than foresight.
Gene are selected which influence the bodies
of the ovenbird and the wasps
and particularly the nervous systems which influence the building behavior.
The birds and the wasps have no idea of why they are doing what they do.
Natural selection simply favors those that build
good nests.
Humans, on the other hand,
do build with foresight.
At least they do usually.
This is an engineer called Ingo Rechenberg from Germany who designs windmills and he claims
that he designs his windmills by a kind of natural selection.
He does it by putting his windmills in a wind tunnel,
measuring how good they are
and then - as he calls it - breeding
from those windmills that are good at spinning around in a wind tunnel.
The windmills have genes, and again, not real genes,
but they are numerical attributes, they're numbers
that are used to make other windmills
that resemble the parent windmill.
And in every generation of windmills he breeds from the ones
that do best in the wind tunnel.
And after many generations of testing them
and breeding, testing and breeding, he ends up with a windmill, he claims, is better
than you would get by the ordinary processes of engineering design.
But you could say that all engineering design and even all art
has a certain Darwinian component.
I want to illustrate this with another computer program
called "biomorphs".
So, can we have a volunteer to run the biomorphs?
What's your name?
Rachel
Rachel. Have you ever used the mouse before?
Yes. Good.
Now,
there you have some biomorphs.
Try one of those now.
What she is doing is guiding the evolution of biomorphs.
The biomorphs are controlled by genes, just like the arthromorphs and just like the spider webs.
And they are coming by random mutation
but the direction of the evolution is being guided by the human eye.
Just like the direction of breeding cabbages or dogs.
In this case we are just looking for pure aesthetic appeal.
Just looking for the prettiest ones.
I think you might imagine
breeding wall paper or bathroom tiles or something like this.
Okay, thank you very much indeed, Rachel.
But in any case, all creation,
all design, all machines, houses and paintings and computers and airplanes,
everything designed and made by us,
everything made by other creatures,
is only made possible
because there are already brains put together as designoid objects.
And designoid objects come about only through gradual evolution.
Creation, when it does occur in the universe,
is an afterthought.
When creation appeared on this planet, it came locally
and it came late.
Creation does not belong in any account of the fundamentals of the universe.
Creation is something that, rather late in the day, grows up in the Universe.
Thank you very much!
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